Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp @ 6026:9f059abe8cf2
7131629: Generalize the CMS free list code
Summary: Make the FreeChunk, FreeList, TreeList, and BinaryTreeDictionary classes usable outside CMS.
Reviewed-by: brutisso, johnc, jwilhelm
Contributed-by: coleen.phillimore@oracle.com
| author | jmasa |
|---|---|
| date | Thu, 29 Mar 2012 19:46:24 -0700 |
| parents | b632e80fc9dc |
| children | f69a5d43dc19 |
| rev | line source |
|---|---|
| 0 | 1 /* |
|
4876
be649fefcdc2
7134655: Crash in reference processing when doing single-threaded remarking
stefank
parents:
4728
diff
changeset
|
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1521
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1521
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1521
diff
changeset
|
21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "classfile/symbolTable.hpp" | |
| 27 #include "classfile/systemDictionary.hpp" | |
| 28 #include "code/codeCache.hpp" | |
| 29 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp" | |
| 30 #include "gc_implementation/concurrentMarkSweep/cmsCollectorPolicy.hpp" | |
| 31 #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp" | |
| 32 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.inline.hpp" | |
| 33 #include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp" | |
| 34 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.inline.hpp" | |
| 35 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" | |
| 36 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp" | |
| 37 #include "gc_implementation/parNew/parNewGeneration.hpp" | |
| 38 #include "gc_implementation/shared/collectorCounters.hpp" | |
| 39 #include "gc_implementation/shared/isGCActiveMark.hpp" | |
| 40 #include "gc_interface/collectedHeap.inline.hpp" | |
| 41 #include "memory/cardTableRS.hpp" | |
| 42 #include "memory/collectorPolicy.hpp" | |
| 43 #include "memory/gcLocker.inline.hpp" | |
| 44 #include "memory/genCollectedHeap.hpp" | |
| 45 #include "memory/genMarkSweep.hpp" | |
| 46 #include "memory/genOopClosures.inline.hpp" | |
| 47 #include "memory/iterator.hpp" | |
| 48 #include "memory/referencePolicy.hpp" | |
| 49 #include "memory/resourceArea.hpp" | |
| 50 #include "oops/oop.inline.hpp" | |
| 51 #include "prims/jvmtiExport.hpp" | |
| 52 #include "runtime/globals_extension.hpp" | |
| 53 #include "runtime/handles.inline.hpp" | |
| 54 #include "runtime/java.hpp" | |
| 55 #include "runtime/vmThread.hpp" | |
| 56 #include "services/memoryService.hpp" | |
| 57 #include "services/runtimeService.hpp" | |
| 0 | 58 |
| 59 // statics | |
| 60 CMSCollector* ConcurrentMarkSweepGeneration::_collector = NULL; | |
| 61 bool CMSCollector::_full_gc_requested = false; | |
| 62 | |
| 63 ////////////////////////////////////////////////////////////////// | |
| 64 // In support of CMS/VM thread synchronization | |
| 65 ////////////////////////////////////////////////////////////////// | |
| 66 // We split use of the CGC_lock into 2 "levels". | |
| 67 // The low-level locking is of the usual CGC_lock monitor. We introduce | |
| 68 // a higher level "token" (hereafter "CMS token") built on top of the | |
| 69 // low level monitor (hereafter "CGC lock"). | |
| 70 // The token-passing protocol gives priority to the VM thread. The | |
| 71 // CMS-lock doesn't provide any fairness guarantees, but clients | |
| 72 // should ensure that it is only held for very short, bounded | |
| 73 // durations. | |
| 74 // | |
| 75 // When either of the CMS thread or the VM thread is involved in | |
| 76 // collection operations during which it does not want the other | |
| 77 // thread to interfere, it obtains the CMS token. | |
| 78 // | |
| 79 // If either thread tries to get the token while the other has | |
| 80 // it, that thread waits. However, if the VM thread and CMS thread | |
| 81 // both want the token, then the VM thread gets priority while the | |
| 82 // CMS thread waits. This ensures, for instance, that the "concurrent" | |
| 83 // phases of the CMS thread's work do not block out the VM thread | |
| 84 // for long periods of time as the CMS thread continues to hog | |
| 85 // the token. (See bug 4616232). | |
| 86 // | |
| 87 // The baton-passing functions are, however, controlled by the | |
| 88 // flags _foregroundGCShouldWait and _foregroundGCIsActive, | |
| 89 // and here the low-level CMS lock, not the high level token, | |
| 90 // ensures mutual exclusion. | |
| 91 // | |
| 92 // Two important conditions that we have to satisfy: | |
| 93 // 1. if a thread does a low-level wait on the CMS lock, then it | |
| 94 // relinquishes the CMS token if it were holding that token | |
| 95 // when it acquired the low-level CMS lock. | |
| 96 // 2. any low-level notifications on the low-level lock | |
| 97 // should only be sent when a thread has relinquished the token. | |
| 98 // | |
| 99 // In the absence of either property, we'd have potential deadlock. | |
| 100 // | |
| 101 // We protect each of the CMS (concurrent and sequential) phases | |
| 102 // with the CMS _token_, not the CMS _lock_. | |
| 103 // | |
| 104 // The only code protected by CMS lock is the token acquisition code | |
| 105 // itself, see ConcurrentMarkSweepThread::[de]synchronize(), and the | |
| 106 // baton-passing code. | |
| 107 // | |
| 108 // Unfortunately, i couldn't come up with a good abstraction to factor and | |
| 109 // hide the naked CGC_lock manipulation in the baton-passing code | |
| 110 // further below. That's something we should try to do. Also, the proof | |
| 111 // of correctness of this 2-level locking scheme is far from obvious, | |
| 112 // and potentially quite slippery. We have an uneasy supsicion, for instance, | |
| 113 // that there may be a theoretical possibility of delay/starvation in the | |
| 114 // low-level lock/wait/notify scheme used for the baton-passing because of | |
| 115 // potential intereference with the priority scheme embodied in the | |
| 116 // CMS-token-passing protocol. See related comments at a CGC_lock->wait() | |
| 117 // invocation further below and marked with "XXX 20011219YSR". | |
| 118 // Indeed, as we note elsewhere, this may become yet more slippery | |
| 119 // in the presence of multiple CMS and/or multiple VM threads. XXX | |
| 120 | |
| 121 class CMSTokenSync: public StackObj { | |
| 122 private: | |
| 123 bool _is_cms_thread; | |
| 124 public: | |
| 125 CMSTokenSync(bool is_cms_thread): | |
| 126 _is_cms_thread(is_cms_thread) { | |
| 127 assert(is_cms_thread == Thread::current()->is_ConcurrentGC_thread(), | |
| 128 "Incorrect argument to constructor"); | |
| 129 ConcurrentMarkSweepThread::synchronize(_is_cms_thread); | |
| 130 } | |
| 131 | |
| 132 ~CMSTokenSync() { | |
| 133 assert(_is_cms_thread ? | |
| 134 ConcurrentMarkSweepThread::cms_thread_has_cms_token() : | |
| 135 ConcurrentMarkSweepThread::vm_thread_has_cms_token(), | |
| 136 "Incorrect state"); | |
| 137 ConcurrentMarkSweepThread::desynchronize(_is_cms_thread); | |
| 138 } | |
| 139 }; | |
| 140 | |
| 141 // Convenience class that does a CMSTokenSync, and then acquires | |
| 142 // upto three locks. | |
| 143 class CMSTokenSyncWithLocks: public CMSTokenSync { | |
| 144 private: | |
| 145 // Note: locks are acquired in textual declaration order | |
| 146 // and released in the opposite order | |
| 147 MutexLockerEx _locker1, _locker2, _locker3; | |
| 148 public: | |
| 149 CMSTokenSyncWithLocks(bool is_cms_thread, Mutex* mutex1, | |
| 150 Mutex* mutex2 = NULL, Mutex* mutex3 = NULL): | |
| 151 CMSTokenSync(is_cms_thread), | |
| 152 _locker1(mutex1, Mutex::_no_safepoint_check_flag), | |
| 153 _locker2(mutex2, Mutex::_no_safepoint_check_flag), | |
| 154 _locker3(mutex3, Mutex::_no_safepoint_check_flag) | |
| 155 { } | |
| 156 }; | |
| 157 | |
| 158 | |
| 159 // Wrapper class to temporarily disable icms during a foreground cms collection. | |
| 160 class ICMSDisabler: public StackObj { | |
| 161 public: | |
| 162 // The ctor disables icms and wakes up the thread so it notices the change; | |
| 163 // the dtor re-enables icms. Note that the CMSCollector methods will check | |
| 164 // CMSIncrementalMode. | |
| 165 ICMSDisabler() { CMSCollector::disable_icms(); CMSCollector::start_icms(); } | |
| 166 ~ICMSDisabler() { CMSCollector::enable_icms(); } | |
| 167 }; | |
| 168 | |
| 169 ////////////////////////////////////////////////////////////////// | |
| 170 // Concurrent Mark-Sweep Generation ///////////////////////////// | |
| 171 ////////////////////////////////////////////////////////////////// | |
| 172 | |
| 173 NOT_PRODUCT(CompactibleFreeListSpace* debug_cms_space;) | |
| 174 | |
| 175 // This struct contains per-thread things necessary to support parallel | |
| 176 // young-gen collection. | |
| 177 class CMSParGCThreadState: public CHeapObj { | |
| 178 public: | |
| 179 CFLS_LAB lab; | |
| 180 PromotionInfo promo; | |
| 181 | |
| 182 // Constructor. | |
| 183 CMSParGCThreadState(CompactibleFreeListSpace* cfls) : lab(cfls) { | |
| 184 promo.setSpace(cfls); | |
| 185 } | |
| 186 }; | |
| 187 | |
| 188 ConcurrentMarkSweepGeneration::ConcurrentMarkSweepGeneration( | |
| 189 ReservedSpace rs, size_t initial_byte_size, int level, | |
| 190 CardTableRS* ct, bool use_adaptive_freelists, | |
| 6026 | 191 FreeBlockDictionary<FreeChunk>::DictionaryChoice dictionaryChoice) : |
| 0 | 192 CardGeneration(rs, initial_byte_size, level, ct), |
|
1571
2d127394260e
6916623: Align object to 16 bytes to use Compressed Oops with java heap up to 64Gb
kvn
parents:
1521
diff
changeset
|
193 _dilatation_factor(((double)MinChunkSize)/((double)(CollectedHeap::min_fill_size()))), |
| 0 | 194 _debug_collection_type(Concurrent_collection_type) |
| 195 { | |
| 196 HeapWord* bottom = (HeapWord*) _virtual_space.low(); | |
| 197 HeapWord* end = (HeapWord*) _virtual_space.high(); | |
| 198 | |
| 199 _direct_allocated_words = 0; | |
| 200 NOT_PRODUCT( | |
| 201 _numObjectsPromoted = 0; | |
| 202 _numWordsPromoted = 0; | |
| 203 _numObjectsAllocated = 0; | |
| 204 _numWordsAllocated = 0; | |
| 205 ) | |
| 206 | |
| 207 _cmsSpace = new CompactibleFreeListSpace(_bts, MemRegion(bottom, end), | |
| 208 use_adaptive_freelists, | |
| 209 dictionaryChoice); | |
| 210 NOT_PRODUCT(debug_cms_space = _cmsSpace;) | |
| 211 if (_cmsSpace == NULL) { | |
| 212 vm_exit_during_initialization( | |
| 213 "CompactibleFreeListSpace allocation failure"); | |
| 214 } | |
| 215 _cmsSpace->_gen = this; | |
| 216 | |
| 217 _gc_stats = new CMSGCStats(); | |
| 218 | |
| 219 // Verify the assumption that FreeChunk::_prev and OopDesc::_klass | |
| 220 // offsets match. The ability to tell free chunks from objects | |
| 221 // depends on this property. | |
| 222 debug_only( | |
| 223 FreeChunk* junk = NULL; | |
| 187 | 224 assert(UseCompressedOops || |
| 225 junk->prev_addr() == (void*)(oop(junk)->klass_addr()), | |
| 0 | 226 "Offset of FreeChunk::_prev within FreeChunk must match" |
| 227 " that of OopDesc::_klass within OopDesc"); | |
| 228 ) | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
229 if (CollectedHeap::use_parallel_gc_threads()) { |
| 0 | 230 typedef CMSParGCThreadState* CMSParGCThreadStatePtr; |
| 231 _par_gc_thread_states = | |
| 232 NEW_C_HEAP_ARRAY(CMSParGCThreadStatePtr, ParallelGCThreads); | |
| 233 if (_par_gc_thread_states == NULL) { | |
| 234 vm_exit_during_initialization("Could not allocate par gc structs"); | |
| 235 } | |
| 236 for (uint i = 0; i < ParallelGCThreads; i++) { | |
| 237 _par_gc_thread_states[i] = new CMSParGCThreadState(cmsSpace()); | |
| 238 if (_par_gc_thread_states[i] == NULL) { | |
| 239 vm_exit_during_initialization("Could not allocate par gc structs"); | |
| 240 } | |
| 241 } | |
| 242 } else { | |
| 243 _par_gc_thread_states = NULL; | |
| 244 } | |
| 245 _incremental_collection_failed = false; | |
| 246 // The "dilatation_factor" is the expansion that can occur on | |
| 247 // account of the fact that the minimum object size in the CMS | |
| 248 // generation may be larger than that in, say, a contiguous young | |
| 249 // generation. | |
| 250 // Ideally, in the calculation below, we'd compute the dilatation | |
| 251 // factor as: MinChunkSize/(promoting_gen's min object size) | |
| 252 // Since we do not have such a general query interface for the | |
| 253 // promoting generation, we'll instead just use the mimimum | |
| 254 // object size (which today is a header's worth of space); | |
| 255 // note that all arithmetic is in units of HeapWords. | |
|
1571
2d127394260e
6916623: Align object to 16 bytes to use Compressed Oops with java heap up to 64Gb
kvn
parents:
1521
diff
changeset
|
256 assert(MinChunkSize >= CollectedHeap::min_fill_size(), "just checking"); |
| 0 | 257 assert(_dilatation_factor >= 1.0, "from previous assert"); |
| 258 } | |
| 259 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
260 |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
261 // The field "_initiating_occupancy" represents the occupancy percentage |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
262 // at which we trigger a new collection cycle. Unless explicitly specified |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
263 // via CMSInitiating[Perm]OccupancyFraction (argument "io" below), it |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
264 // is calculated by: |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
265 // |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
266 // Let "f" be MinHeapFreeRatio in |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
267 // |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
268 // _intiating_occupancy = 100-f + |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
269 // f * (CMSTrigger[Perm]Ratio/100) |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
270 // where CMSTrigger[Perm]Ratio is the argument "tr" below. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
271 // |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
272 // That is, if we assume the heap is at its desired maximum occupancy at the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
273 // end of a collection, we let CMSTrigger[Perm]Ratio of the (purported) free |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
274 // space be allocated before initiating a new collection cycle. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
275 // |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
276 void ConcurrentMarkSweepGeneration::init_initiating_occupancy(intx io, intx tr) { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
277 assert(io <= 100 && tr >= 0 && tr <= 100, "Check the arguments"); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
278 if (io >= 0) { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
279 _initiating_occupancy = (double)io / 100.0; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
280 } else { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
281 _initiating_occupancy = ((100 - MinHeapFreeRatio) + |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
282 (double)(tr * MinHeapFreeRatio) / 100.0) |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
283 / 100.0; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
284 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
285 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
286 |
| 0 | 287 void ConcurrentMarkSweepGeneration::ref_processor_init() { |
| 288 assert(collector() != NULL, "no collector"); | |
| 289 collector()->ref_processor_init(); | |
| 290 } | |
| 291 | |
| 292 void CMSCollector::ref_processor_init() { | |
| 293 if (_ref_processor == NULL) { | |
| 294 // Allocate and initialize a reference processor | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
295 _ref_processor = |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
296 new ReferenceProcessor(_span, // span |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
297 (ParallelGCThreads > 1) && ParallelRefProcEnabled, // mt processing |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
298 (int) ParallelGCThreads, // mt processing degree |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
299 _cmsGen->refs_discovery_is_mt(), // mt discovery |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
300 (int) MAX2(ConcGCThreads, ParallelGCThreads), // mt discovery degree |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
301 _cmsGen->refs_discovery_is_atomic(), // discovery is not atomic |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
302 &_is_alive_closure, // closure for liveness info |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
303 false); // next field updates do not need write barrier |
| 0 | 304 // Initialize the _ref_processor field of CMSGen |
| 305 _cmsGen->set_ref_processor(_ref_processor); | |
| 306 | |
| 307 // Allocate a dummy ref processor for perm gen. | |
| 308 ReferenceProcessor* rp2 = new ReferenceProcessor(); | |
| 309 if (rp2 == NULL) { | |
| 310 vm_exit_during_initialization("Could not allocate ReferenceProcessor object"); | |
| 311 } | |
| 312 _permGen->set_ref_processor(rp2); | |
| 313 } | |
| 314 } | |
| 315 | |
| 316 CMSAdaptiveSizePolicy* CMSCollector::size_policy() { | |
| 317 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 318 assert(gch->kind() == CollectedHeap::GenCollectedHeap, | |
| 319 "Wrong type of heap"); | |
| 320 CMSAdaptiveSizePolicy* sp = (CMSAdaptiveSizePolicy*) | |
| 321 gch->gen_policy()->size_policy(); | |
| 322 assert(sp->is_gc_cms_adaptive_size_policy(), | |
| 323 "Wrong type of size policy"); | |
| 324 return sp; | |
| 325 } | |
| 326 | |
| 327 CMSGCAdaptivePolicyCounters* CMSCollector::gc_adaptive_policy_counters() { | |
| 328 CMSGCAdaptivePolicyCounters* results = | |
| 329 (CMSGCAdaptivePolicyCounters*) collector_policy()->counters(); | |
| 330 assert( | |
| 331 results->kind() == GCPolicyCounters::CMSGCAdaptivePolicyCountersKind, | |
| 332 "Wrong gc policy counter kind"); | |
| 333 return results; | |
| 334 } | |
| 335 | |
| 336 | |
| 337 void ConcurrentMarkSweepGeneration::initialize_performance_counters() { | |
| 338 | |
| 339 const char* gen_name = "old"; | |
| 340 | |
| 341 // Generation Counters - generation 1, 1 subspace | |
| 342 _gen_counters = new GenerationCounters(gen_name, 1, 1, &_virtual_space); | |
| 343 | |
| 344 _space_counters = new GSpaceCounters(gen_name, 0, | |
| 345 _virtual_space.reserved_size(), | |
| 346 this, _gen_counters); | |
| 347 } | |
| 348 | |
| 349 CMSStats::CMSStats(ConcurrentMarkSweepGeneration* cms_gen, unsigned int alpha): | |
| 350 _cms_gen(cms_gen) | |
| 351 { | |
| 352 assert(alpha <= 100, "bad value"); | |
| 353 _saved_alpha = alpha; | |
| 354 | |
| 355 // Initialize the alphas to the bootstrap value of 100. | |
| 356 _gc0_alpha = _cms_alpha = 100; | |
| 357 | |
| 358 _cms_begin_time.update(); | |
| 359 _cms_end_time.update(); | |
| 360 | |
| 361 _gc0_duration = 0.0; | |
| 362 _gc0_period = 0.0; | |
| 363 _gc0_promoted = 0; | |
| 364 | |
| 365 _cms_duration = 0.0; | |
| 366 _cms_period = 0.0; | |
| 367 _cms_allocated = 0; | |
| 368 | |
| 369 _cms_used_at_gc0_begin = 0; | |
| 370 _cms_used_at_gc0_end = 0; | |
| 371 _allow_duty_cycle_reduction = false; | |
| 372 _valid_bits = 0; | |
| 373 _icms_duty_cycle = CMSIncrementalDutyCycle; | |
| 374 } | |
| 375 | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
376 double CMSStats::cms_free_adjustment_factor(size_t free) const { |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
377 // TBD: CR 6909490 |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
378 return 1.0; |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
379 } |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
380 |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
381 void CMSStats::adjust_cms_free_adjustment_factor(bool fail, size_t free) { |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
382 } |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
383 |
| 0 | 384 // If promotion failure handling is on use |
| 385 // the padded average size of the promotion for each | |
| 386 // young generation collection. | |
| 387 double CMSStats::time_until_cms_gen_full() const { | |
| 388 size_t cms_free = _cms_gen->cmsSpace()->free(); | |
| 389 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
|
1888
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
390 size_t expected_promotion = MIN2(gch->get_gen(0)->capacity(), |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
391 (size_t) _cms_gen->gc_stats()->avg_promoted()->padded_average()); |
| 0 | 392 if (cms_free > expected_promotion) { |
| 393 // Start a cms collection if there isn't enough space to promote | |
| 394 // for the next minor collection. Use the padded average as | |
| 395 // a safety factor. | |
| 396 cms_free -= expected_promotion; | |
| 397 | |
| 398 // Adjust by the safety factor. | |
| 399 double cms_free_dbl = (double)cms_free; | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
400 double cms_adjustment = (100.0 - CMSIncrementalSafetyFactor)/100.0; |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
401 // Apply a further correction factor which tries to adjust |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
402 // for recent occurance of concurrent mode failures. |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
403 cms_adjustment = cms_adjustment * cms_free_adjustment_factor(cms_free); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
404 cms_free_dbl = cms_free_dbl * cms_adjustment; |
| 0 | 405 |
| 406 if (PrintGCDetails && Verbose) { | |
| 407 gclog_or_tty->print_cr("CMSStats::time_until_cms_gen_full: cms_free " | |
| 408 SIZE_FORMAT " expected_promotion " SIZE_FORMAT, | |
| 409 cms_free, expected_promotion); | |
| 410 gclog_or_tty->print_cr(" cms_free_dbl %f cms_consumption_rate %f", | |
| 411 cms_free_dbl, cms_consumption_rate() + 1.0); | |
| 412 } | |
| 413 // Add 1 in case the consumption rate goes to zero. | |
| 414 return cms_free_dbl / (cms_consumption_rate() + 1.0); | |
| 415 } | |
| 416 return 0.0; | |
| 417 } | |
| 418 | |
| 419 // Compare the duration of the cms collection to the | |
| 420 // time remaining before the cms generation is empty. | |
| 421 // Note that the time from the start of the cms collection | |
| 422 // to the start of the cms sweep (less than the total | |
| 423 // duration of the cms collection) can be used. This | |
| 424 // has been tried and some applications experienced | |
| 425 // promotion failures early in execution. This was | |
| 426 // possibly because the averages were not accurate | |
| 427 // enough at the beginning. | |
| 428 double CMSStats::time_until_cms_start() const { | |
| 429 // We add "gc0_period" to the "work" calculation | |
| 430 // below because this query is done (mostly) at the | |
| 431 // end of a scavenge, so we need to conservatively | |
| 432 // account for that much possible delay | |
| 433 // in the query so as to avoid concurrent mode failures | |
| 434 // due to starting the collection just a wee bit too | |
| 435 // late. | |
| 436 double work = cms_duration() + gc0_period(); | |
| 437 double deadline = time_until_cms_gen_full(); | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
438 // If a concurrent mode failure occurred recently, we want to be |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
439 // more conservative and halve our expected time_until_cms_gen_full() |
| 0 | 440 if (work > deadline) { |
| 441 if (Verbose && PrintGCDetails) { | |
| 442 gclog_or_tty->print( | |
| 443 " CMSCollector: collect because of anticipated promotion " | |
| 444 "before full %3.7f + %3.7f > %3.7f ", cms_duration(), | |
| 445 gc0_period(), time_until_cms_gen_full()); | |
| 446 } | |
| 447 return 0.0; | |
| 448 } | |
| 449 return work - deadline; | |
| 450 } | |
| 451 | |
| 452 // Return a duty cycle based on old_duty_cycle and new_duty_cycle, limiting the | |
| 453 // amount of change to prevent wild oscillation. | |
| 454 unsigned int CMSStats::icms_damped_duty_cycle(unsigned int old_duty_cycle, | |
| 455 unsigned int new_duty_cycle) { | |
| 456 assert(old_duty_cycle <= 100, "bad input value"); | |
| 457 assert(new_duty_cycle <= 100, "bad input value"); | |
| 458 | |
| 459 // Note: use subtraction with caution since it may underflow (values are | |
| 460 // unsigned). Addition is safe since we're in the range 0-100. | |
| 461 unsigned int damped_duty_cycle = new_duty_cycle; | |
| 462 if (new_duty_cycle < old_duty_cycle) { | |
| 463 const unsigned int largest_delta = MAX2(old_duty_cycle / 4, 5U); | |
| 464 if (new_duty_cycle + largest_delta < old_duty_cycle) { | |
| 465 damped_duty_cycle = old_duty_cycle - largest_delta; | |
| 466 } | |
| 467 } else if (new_duty_cycle > old_duty_cycle) { | |
| 468 const unsigned int largest_delta = MAX2(old_duty_cycle / 4, 15U); | |
| 469 if (new_duty_cycle > old_duty_cycle + largest_delta) { | |
| 470 damped_duty_cycle = MIN2(old_duty_cycle + largest_delta, 100U); | |
| 471 } | |
| 472 } | |
| 473 assert(damped_duty_cycle <= 100, "invalid duty cycle computed"); | |
| 474 | |
| 475 if (CMSTraceIncrementalPacing) { | |
| 476 gclog_or_tty->print(" [icms_damped_duty_cycle(%d,%d) = %d] ", | |
| 477 old_duty_cycle, new_duty_cycle, damped_duty_cycle); | |
| 478 } | |
| 479 return damped_duty_cycle; | |
| 480 } | |
| 481 | |
| 482 unsigned int CMSStats::icms_update_duty_cycle_impl() { | |
| 483 assert(CMSIncrementalPacing && valid(), | |
| 484 "should be handled in icms_update_duty_cycle()"); | |
| 485 | |
| 486 double cms_time_so_far = cms_timer().seconds(); | |
| 487 double scaled_duration = cms_duration_per_mb() * _cms_used_at_gc0_end / M; | |
| 488 double scaled_duration_remaining = fabsd(scaled_duration - cms_time_so_far); | |
| 489 | |
| 490 // Avoid division by 0. | |
| 491 double time_until_full = MAX2(time_until_cms_gen_full(), 0.01); | |
| 492 double duty_cycle_dbl = 100.0 * scaled_duration_remaining / time_until_full; | |
| 493 | |
| 494 unsigned int new_duty_cycle = MIN2((unsigned int)duty_cycle_dbl, 100U); | |
| 495 if (new_duty_cycle > _icms_duty_cycle) { | |
| 496 // Avoid very small duty cycles (1 or 2); 0 is allowed. | |
| 497 if (new_duty_cycle > 2) { | |
| 498 _icms_duty_cycle = icms_damped_duty_cycle(_icms_duty_cycle, | |
| 499 new_duty_cycle); | |
| 500 } | |
| 501 } else if (_allow_duty_cycle_reduction) { | |
| 502 // The duty cycle is reduced only once per cms cycle (see record_cms_end()). | |
| 503 new_duty_cycle = icms_damped_duty_cycle(_icms_duty_cycle, new_duty_cycle); | |
| 504 // Respect the minimum duty cycle. | |
| 505 unsigned int min_duty_cycle = (unsigned int)CMSIncrementalDutyCycleMin; | |
| 506 _icms_duty_cycle = MAX2(new_duty_cycle, min_duty_cycle); | |
| 507 } | |
| 508 | |
| 509 if (PrintGCDetails || CMSTraceIncrementalPacing) { | |
| 510 gclog_or_tty->print(" icms_dc=%d ", _icms_duty_cycle); | |
| 511 } | |
| 512 | |
| 513 _allow_duty_cycle_reduction = false; | |
| 514 return _icms_duty_cycle; | |
| 515 } | |
| 516 | |
| 517 #ifndef PRODUCT | |
| 518 void CMSStats::print_on(outputStream *st) const { | |
| 519 st->print(" gc0_alpha=%d,cms_alpha=%d", _gc0_alpha, _cms_alpha); | |
| 520 st->print(",gc0_dur=%g,gc0_per=%g,gc0_promo=" SIZE_FORMAT, | |
| 521 gc0_duration(), gc0_period(), gc0_promoted()); | |
| 522 st->print(",cms_dur=%g,cms_dur_per_mb=%g,cms_per=%g,cms_alloc=" SIZE_FORMAT, | |
| 523 cms_duration(), cms_duration_per_mb(), | |
| 524 cms_period(), cms_allocated()); | |
| 525 st->print(",cms_since_beg=%g,cms_since_end=%g", | |
| 526 cms_time_since_begin(), cms_time_since_end()); | |
| 527 st->print(",cms_used_beg=" SIZE_FORMAT ",cms_used_end=" SIZE_FORMAT, | |
| 528 _cms_used_at_gc0_begin, _cms_used_at_gc0_end); | |
| 529 if (CMSIncrementalMode) { | |
| 530 st->print(",dc=%d", icms_duty_cycle()); | |
| 531 } | |
| 532 | |
| 533 if (valid()) { | |
| 534 st->print(",promo_rate=%g,cms_alloc_rate=%g", | |
| 535 promotion_rate(), cms_allocation_rate()); | |
| 536 st->print(",cms_consumption_rate=%g,time_until_full=%g", | |
| 537 cms_consumption_rate(), time_until_cms_gen_full()); | |
| 538 } | |
| 539 st->print(" "); | |
| 540 } | |
| 541 #endif // #ifndef PRODUCT | |
| 542 | |
| 543 CMSCollector::CollectorState CMSCollector::_collectorState = | |
| 544 CMSCollector::Idling; | |
| 545 bool CMSCollector::_foregroundGCIsActive = false; | |
| 546 bool CMSCollector::_foregroundGCShouldWait = false; | |
| 547 | |
| 548 CMSCollector::CMSCollector(ConcurrentMarkSweepGeneration* cmsGen, | |
| 549 ConcurrentMarkSweepGeneration* permGen, | |
| 550 CardTableRS* ct, | |
| 551 ConcurrentMarkSweepPolicy* cp): | |
| 552 _cmsGen(cmsGen), | |
| 553 _permGen(permGen), | |
| 554 _ct(ct), | |
| 555 _ref_processor(NULL), // will be set later | |
| 556 _conc_workers(NULL), // may be set later | |
| 557 _abort_preclean(false), | |
| 558 _start_sampling(false), | |
| 559 _between_prologue_and_epilogue(false), | |
| 560 _markBitMap(0, Mutex::leaf + 1, "CMS_markBitMap_lock"), | |
| 561 _perm_gen_verify_bit_map(0, -1 /* no mutex */, "No_lock"), | |
| 562 _modUnionTable((CardTableModRefBS::card_shift - LogHeapWordSize), | |
| 563 -1 /* lock-free */, "No_lock" /* dummy */), | |
| 564 _modUnionClosure(&_modUnionTable), | |
| 565 _modUnionClosurePar(&_modUnionTable), | |
|
143
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
566 // Adjust my span to cover old (cms) gen and perm gen |
|
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
567 _span(cmsGen->reserved()._union(permGen->reserved())), |
|
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
568 // Construct the is_alive_closure with _span & markBitMap |
|
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
569 _is_alive_closure(_span, &_markBitMap), |
| 0 | 570 _restart_addr(NULL), |
| 571 _overflow_list(NULL), | |
| 572 _stats(cmsGen), | |
| 573 _eden_chunk_array(NULL), // may be set in ctor body | |
| 574 _eden_chunk_capacity(0), // -- ditto -- | |
| 575 _eden_chunk_index(0), // -- ditto -- | |
| 576 _survivor_plab_array(NULL), // -- ditto -- | |
| 577 _survivor_chunk_array(NULL), // -- ditto -- | |
| 578 _survivor_chunk_capacity(0), // -- ditto -- | |
| 579 _survivor_chunk_index(0), // -- ditto -- | |
| 580 _ser_pmc_preclean_ovflw(0), | |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
581 _ser_kac_preclean_ovflw(0), |
| 0 | 582 _ser_pmc_remark_ovflw(0), |
| 583 _par_pmc_remark_ovflw(0), | |
| 584 _ser_kac_ovflw(0), | |
| 585 _par_kac_ovflw(0), | |
| 586 #ifndef PRODUCT | |
| 587 _num_par_pushes(0), | |
| 588 #endif | |
| 589 _collection_count_start(0), | |
| 590 _verifying(false), | |
| 591 _icms_start_limit(NULL), | |
| 592 _icms_stop_limit(NULL), | |
| 593 _verification_mark_bm(0, Mutex::leaf + 1, "CMS_verification_mark_bm_lock"), | |
| 594 _completed_initialization(false), | |
| 595 _collector_policy(cp), | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
596 _should_unload_classes(false), |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
597 _concurrent_cycles_since_last_unload(0), |
|
798
fe1574da39fc
6848641: CMSCollector::_roots_scanning_options should be initialized
ysr
parents:
679
diff
changeset
|
598 _roots_scanning_options(0), |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
599 _inter_sweep_estimate(CMS_SweepWeight, CMS_SweepPadding), |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
600 _intra_sweep_estimate(CMS_SweepWeight, CMS_SweepPadding) |
| 0 | 601 { |
| 602 if (ExplicitGCInvokesConcurrentAndUnloadsClasses) { | |
| 603 ExplicitGCInvokesConcurrent = true; | |
| 604 } | |
| 605 // Now expand the span and allocate the collection support structures | |
| 606 // (MUT, marking bit map etc.) to cover both generations subject to | |
| 607 // collection. | |
| 608 | |
| 609 // First check that _permGen is adjacent to _cmsGen and above it. | |
| 610 assert( _cmsGen->reserved().word_size() > 0 | |
| 611 && _permGen->reserved().word_size() > 0, | |
| 612 "generations should not be of zero size"); | |
| 613 assert(_cmsGen->reserved().intersection(_permGen->reserved()).is_empty(), | |
| 614 "_cmsGen and _permGen should not overlap"); | |
| 615 assert(_cmsGen->reserved().end() == _permGen->reserved().start(), | |
| 616 "_cmsGen->end() different from _permGen->start()"); | |
| 617 | |
| 618 // For use by dirty card to oop closures. | |
| 619 _cmsGen->cmsSpace()->set_collector(this); | |
| 620 _permGen->cmsSpace()->set_collector(this); | |
| 621 | |
| 622 // Allocate MUT and marking bit map | |
| 623 { | |
| 624 MutexLockerEx x(_markBitMap.lock(), Mutex::_no_safepoint_check_flag); | |
| 625 if (!_markBitMap.allocate(_span)) { | |
| 626 warning("Failed to allocate CMS Bit Map"); | |
| 627 return; | |
| 628 } | |
| 629 assert(_markBitMap.covers(_span), "_markBitMap inconsistency?"); | |
| 630 } | |
| 631 { | |
| 632 _modUnionTable.allocate(_span); | |
| 633 assert(_modUnionTable.covers(_span), "_modUnionTable inconsistency?"); | |
| 634 } | |
| 635 | |
| 1284 | 636 if (!_markStack.allocate(MarkStackSize)) { |
| 0 | 637 warning("Failed to allocate CMS Marking Stack"); |
| 638 return; | |
| 639 } | |
| 640 if (!_revisitStack.allocate(CMSRevisitStackSize)) { | |
| 641 warning("Failed to allocate CMS Revisit Stack"); | |
| 642 return; | |
| 643 } | |
| 644 | |
| 645 // Support for multi-threaded concurrent phases | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
646 if (CMSConcurrentMTEnabled) { |
| 1284 | 647 if (FLAG_IS_DEFAULT(ConcGCThreads)) { |
| 0 | 648 // just for now |
| 1284 | 649 FLAG_SET_DEFAULT(ConcGCThreads, (ParallelGCThreads + 3)/4); |
| 650 } | |
| 651 if (ConcGCThreads > 1) { | |
| 0 | 652 _conc_workers = new YieldingFlexibleWorkGang("Parallel CMS Threads", |
| 1284 | 653 ConcGCThreads, true); |
| 0 | 654 if (_conc_workers == NULL) { |
| 655 warning("GC/CMS: _conc_workers allocation failure: " | |
| 656 "forcing -CMSConcurrentMTEnabled"); | |
| 657 CMSConcurrentMTEnabled = false; | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
658 } else { |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
659 _conc_workers->initialize_workers(); |
| 0 | 660 } |
| 661 } else { | |
| 662 CMSConcurrentMTEnabled = false; | |
| 663 } | |
| 664 } | |
| 665 if (!CMSConcurrentMTEnabled) { | |
| 1284 | 666 ConcGCThreads = 0; |
| 0 | 667 } else { |
| 668 // Turn off CMSCleanOnEnter optimization temporarily for | |
| 669 // the MT case where it's not fixed yet; see 6178663. | |
| 670 CMSCleanOnEnter = false; | |
| 671 } | |
| 1284 | 672 assert((_conc_workers != NULL) == (ConcGCThreads > 1), |
| 0 | 673 "Inconsistency"); |
| 674 | |
| 675 // Parallel task queues; these are shared for the | |
| 676 // concurrent and stop-world phases of CMS, but | |
| 677 // are not shared with parallel scavenge (ParNew). | |
| 678 { | |
| 679 uint i; | |
| 1284 | 680 uint num_queues = (uint) MAX2(ParallelGCThreads, ConcGCThreads); |
| 0 | 681 |
| 682 if ((CMSParallelRemarkEnabled || CMSConcurrentMTEnabled | |
| 683 || ParallelRefProcEnabled) | |
| 684 && num_queues > 0) { | |
| 685 _task_queues = new OopTaskQueueSet(num_queues); | |
| 686 if (_task_queues == NULL) { | |
| 687 warning("task_queues allocation failure."); | |
| 688 return; | |
| 689 } | |
| 690 _hash_seed = NEW_C_HEAP_ARRAY(int, num_queues); | |
| 691 if (_hash_seed == NULL) { | |
| 692 warning("_hash_seed array allocation failure"); | |
| 693 return; | |
| 694 } | |
| 695 | |
| 1665 | 696 typedef Padded<OopTaskQueue> PaddedOopTaskQueue; |
| 0 | 697 for (i = 0; i < num_queues; i++) { |
| 1665 | 698 PaddedOopTaskQueue *q = new PaddedOopTaskQueue(); |
| 699 if (q == NULL) { | |
| 0 | 700 warning("work_queue allocation failure."); |
| 701 return; | |
| 702 } | |
| 1665 | 703 _task_queues->register_queue(i, q); |
| 0 | 704 } |
| 705 for (i = 0; i < num_queues; i++) { | |
| 706 _task_queues->queue(i)->initialize(); | |
| 707 _hash_seed[i] = 17; // copied from ParNew | |
| 708 } | |
| 709 } | |
| 710 } | |
| 711 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
712 _cmsGen ->init_initiating_occupancy(CMSInitiatingOccupancyFraction, CMSTriggerRatio); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
713 _permGen->init_initiating_occupancy(CMSInitiatingPermOccupancyFraction, CMSTriggerPermRatio); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
714 |
| 0 | 715 // Clip CMSBootstrapOccupancy between 0 and 100. |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
716 _bootstrap_occupancy = ((double)MIN2((uintx)100, MAX2((uintx)0, CMSBootstrapOccupancy))) |
| 0 | 717 /(double)100; |
| 718 | |
| 719 _full_gcs_since_conc_gc = 0; | |
| 720 | |
| 721 // Now tell CMS generations the identity of their collector | |
| 722 ConcurrentMarkSweepGeneration::set_collector(this); | |
| 723 | |
| 724 // Create & start a CMS thread for this CMS collector | |
| 725 _cmsThread = ConcurrentMarkSweepThread::start(this); | |
| 726 assert(cmsThread() != NULL, "CMS Thread should have been created"); | |
| 727 assert(cmsThread()->collector() == this, | |
| 728 "CMS Thread should refer to this gen"); | |
| 729 assert(CGC_lock != NULL, "Where's the CGC_lock?"); | |
| 730 | |
| 731 // Support for parallelizing young gen rescan | |
| 732 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 733 _young_gen = gch->prev_gen(_cmsGen); | |
| 734 if (gch->supports_inline_contig_alloc()) { | |
| 735 _top_addr = gch->top_addr(); | |
| 736 _end_addr = gch->end_addr(); | |
| 737 assert(_young_gen != NULL, "no _young_gen"); | |
| 738 _eden_chunk_index = 0; | |
| 739 _eden_chunk_capacity = (_young_gen->max_capacity()+CMSSamplingGrain)/CMSSamplingGrain; | |
| 740 _eden_chunk_array = NEW_C_HEAP_ARRAY(HeapWord*, _eden_chunk_capacity); | |
| 741 if (_eden_chunk_array == NULL) { | |
| 742 _eden_chunk_capacity = 0; | |
| 743 warning("GC/CMS: _eden_chunk_array allocation failure"); | |
| 744 } | |
| 745 } | |
| 746 assert(_eden_chunk_array != NULL || _eden_chunk_capacity == 0, "Error"); | |
| 747 | |
| 748 // Support for parallelizing survivor space rescan | |
| 749 if (CMSParallelRemarkEnabled && CMSParallelSurvivorRemarkEnabled) { | |
|
1289
d47555d7aca8
6910182: CMS: assert(_cursor[j] == _survivor_plab_array[j].end(),"Ctl pt invariant")
jmasa
parents:
1284
diff
changeset
|
750 const size_t max_plab_samples = |
|
d47555d7aca8
6910182: CMS: assert(_cursor[j] == _survivor_plab_array[j].end(),"Ctl pt invariant")
jmasa
parents:
1284
diff
changeset
|
751 ((DefNewGeneration*)_young_gen)->max_survivor_size()/MinTLABSize; |
|
d47555d7aca8
6910182: CMS: assert(_cursor[j] == _survivor_plab_array[j].end(),"Ctl pt invariant")
jmasa
parents:
1284
diff
changeset
|
752 |
| 0 | 753 _survivor_plab_array = NEW_C_HEAP_ARRAY(ChunkArray, ParallelGCThreads); |
| 754 _survivor_chunk_array = NEW_C_HEAP_ARRAY(HeapWord*, 2*max_plab_samples); | |
| 755 _cursor = NEW_C_HEAP_ARRAY(size_t, ParallelGCThreads); | |
| 756 if (_survivor_plab_array == NULL || _survivor_chunk_array == NULL | |
| 757 || _cursor == NULL) { | |
| 758 warning("Failed to allocate survivor plab/chunk array"); | |
| 759 if (_survivor_plab_array != NULL) { | |
| 760 FREE_C_HEAP_ARRAY(ChunkArray, _survivor_plab_array); | |
| 761 _survivor_plab_array = NULL; | |
| 762 } | |
| 763 if (_survivor_chunk_array != NULL) { | |
| 764 FREE_C_HEAP_ARRAY(HeapWord*, _survivor_chunk_array); | |
| 765 _survivor_chunk_array = NULL; | |
| 766 } | |
| 767 if (_cursor != NULL) { | |
| 768 FREE_C_HEAP_ARRAY(size_t, _cursor); | |
| 769 _cursor = NULL; | |
| 770 } | |
| 771 } else { | |
| 772 _survivor_chunk_capacity = 2*max_plab_samples; | |
| 773 for (uint i = 0; i < ParallelGCThreads; i++) { | |
| 774 HeapWord** vec = NEW_C_HEAP_ARRAY(HeapWord*, max_plab_samples); | |
| 775 if (vec == NULL) { | |
| 776 warning("Failed to allocate survivor plab array"); | |
| 777 for (int j = i; j > 0; j--) { | |
| 778 FREE_C_HEAP_ARRAY(HeapWord*, _survivor_plab_array[j-1].array()); | |
| 779 } | |
| 780 FREE_C_HEAP_ARRAY(ChunkArray, _survivor_plab_array); | |
| 781 FREE_C_HEAP_ARRAY(HeapWord*, _survivor_chunk_array); | |
| 782 _survivor_plab_array = NULL; | |
| 783 _survivor_chunk_array = NULL; | |
| 784 _survivor_chunk_capacity = 0; | |
| 785 break; | |
| 786 } else { | |
| 787 ChunkArray* cur = | |
| 788 ::new (&_survivor_plab_array[i]) ChunkArray(vec, | |
| 789 max_plab_samples); | |
| 790 assert(cur->end() == 0, "Should be 0"); | |
| 791 assert(cur->array() == vec, "Should be vec"); | |
| 792 assert(cur->capacity() == max_plab_samples, "Error"); | |
| 793 } | |
| 794 } | |
| 795 } | |
| 796 } | |
| 797 assert( ( _survivor_plab_array != NULL | |
| 798 && _survivor_chunk_array != NULL) | |
| 799 || ( _survivor_chunk_capacity == 0 | |
| 800 && _survivor_chunk_index == 0), | |
| 801 "Error"); | |
| 802 | |
| 803 // Choose what strong roots should be scanned depending on verification options | |
| 804 // and perm gen collection mode. | |
| 805 if (!CMSClassUnloadingEnabled) { | |
| 806 // If class unloading is disabled we want to include all classes into the root set. | |
| 807 add_root_scanning_option(SharedHeap::SO_AllClasses); | |
| 808 } else { | |
| 809 add_root_scanning_option(SharedHeap::SO_SystemClasses); | |
| 810 } | |
| 811 | |
| 812 NOT_PRODUCT(_overflow_counter = CMSMarkStackOverflowInterval;) | |
| 813 _gc_counters = new CollectorCounters("CMS", 1); | |
| 814 _completed_initialization = true; | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
815 _inter_sweep_timer.start(); // start of time |
|
1518
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
816 #ifdef SPARC |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
817 // Issue a stern warning, but allow use for experimentation and debugging. |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
818 if (VM_Version::is_sun4v() && UseMemSetInBOT) { |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
819 assert(!FLAG_IS_DEFAULT(UseMemSetInBOT), "Error"); |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
820 warning("Experimental flag -XX:+UseMemSetInBOT is known to cause instability" |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
821 " on sun4v; please understand that you are using at your own risk!"); |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
822 } |
|
3bfae429e2cf
6948537: CMS: BOT walkers observe out-of-thin-air zeros on sun4v sparc/CMT
ysr
parents:
1387
diff
changeset
|
823 #endif |
| 0 | 824 } |
| 825 | |
| 826 const char* ConcurrentMarkSweepGeneration::name() const { | |
| 827 return "concurrent mark-sweep generation"; | |
| 828 } | |
| 829 void ConcurrentMarkSweepGeneration::update_counters() { | |
| 830 if (UsePerfData) { | |
| 831 _space_counters->update_all(); | |
| 832 _gen_counters->update_all(); | |
| 833 } | |
| 834 } | |
| 835 | |
| 836 // this is an optimized version of update_counters(). it takes the | |
| 837 // used value as a parameter rather than computing it. | |
| 838 // | |
| 839 void ConcurrentMarkSweepGeneration::update_counters(size_t used) { | |
| 840 if (UsePerfData) { | |
| 841 _space_counters->update_used(used); | |
| 842 _space_counters->update_capacity(); | |
| 843 _gen_counters->update_all(); | |
| 844 } | |
| 845 } | |
| 846 | |
| 847 void ConcurrentMarkSweepGeneration::print() const { | |
| 848 Generation::print(); | |
| 849 cmsSpace()->print(); | |
| 850 } | |
| 851 | |
| 852 #ifndef PRODUCT | |
| 853 void ConcurrentMarkSweepGeneration::print_statistics() { | |
| 854 cmsSpace()->printFLCensus(0); | |
| 855 } | |
| 856 #endif | |
| 857 | |
| 858 void ConcurrentMarkSweepGeneration::printOccupancy(const char *s) { | |
| 859 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 860 if (PrintGCDetails) { | |
| 861 if (Verbose) { | |
| 862 gclog_or_tty->print(" [%d %s-%s: "SIZE_FORMAT"("SIZE_FORMAT")]", | |
| 863 level(), short_name(), s, used(), capacity()); | |
| 864 } else { | |
| 865 gclog_or_tty->print(" [%d %s-%s: "SIZE_FORMAT"K("SIZE_FORMAT"K)]", | |
| 866 level(), short_name(), s, used() / K, capacity() / K); | |
| 867 } | |
| 868 } | |
| 869 if (Verbose) { | |
| 870 gclog_or_tty->print(" "SIZE_FORMAT"("SIZE_FORMAT")", | |
| 871 gch->used(), gch->capacity()); | |
| 872 } else { | |
| 873 gclog_or_tty->print(" "SIZE_FORMAT"K("SIZE_FORMAT"K)", | |
| 874 gch->used() / K, gch->capacity() / K); | |
| 875 } | |
| 876 } | |
| 877 | |
| 878 size_t | |
| 879 ConcurrentMarkSweepGeneration::contiguous_available() const { | |
| 880 // dld proposes an improvement in precision here. If the committed | |
| 881 // part of the space ends in a free block we should add that to | |
| 882 // uncommitted size in the calculation below. Will make this | |
| 883 // change later, staying with the approximation below for the | |
| 884 // time being. -- ysr. | |
| 885 return MAX2(_virtual_space.uncommitted_size(), unsafe_max_alloc_nogc()); | |
| 886 } | |
| 887 | |
| 888 size_t | |
| 889 ConcurrentMarkSweepGeneration::unsafe_max_alloc_nogc() const { | |
| 890 return _cmsSpace->max_alloc_in_words() * HeapWordSize; | |
| 891 } | |
| 892 | |
| 893 size_t ConcurrentMarkSweepGeneration::max_available() const { | |
| 894 return free() + _virtual_space.uncommitted_size(); | |
| 895 } | |
| 896 | |
|
1888
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
897 bool ConcurrentMarkSweepGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const { |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
898 size_t available = max_available(); |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
899 size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average(); |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
900 bool res = (available >= av_promo) || (available >= max_promotion_in_bytes); |
|
1994
6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
ysr
parents:
1972
diff
changeset
|
901 if (Verbose && PrintGCDetails) { |
|
1888
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
902 gclog_or_tty->print_cr( |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
903 "CMS: promo attempt is%s safe: available("SIZE_FORMAT") %s av_promo("SIZE_FORMAT")," |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
904 "max_promo("SIZE_FORMAT")", |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
905 res? "":" not", available, res? ">=":"<", |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
906 av_promo, max_promotion_in_bytes); |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
907 } |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
908 return res; |
| 0 | 909 } |
| 910 | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
911 // At a promotion failure dump information on block layout in heap |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
912 // (cms old generation). |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
913 void ConcurrentMarkSweepGeneration::promotion_failure_occurred() { |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
914 if (CMSDumpAtPromotionFailure) { |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
915 cmsSpace()->dump_at_safepoint_with_locks(collector(), gclog_or_tty); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
916 } |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
917 } |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
918 |
| 0 | 919 CompactibleSpace* |
| 920 ConcurrentMarkSweepGeneration::first_compaction_space() const { | |
| 921 return _cmsSpace; | |
| 922 } | |
| 923 | |
| 924 void ConcurrentMarkSweepGeneration::reset_after_compaction() { | |
| 925 // Clear the promotion information. These pointers can be adjusted | |
| 926 // along with all the other pointers into the heap but | |
| 927 // compaction is expected to be a rare event with | |
| 928 // a heap using cms so don't do it without seeing the need. | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
929 if (CollectedHeap::use_parallel_gc_threads()) { |
| 0 | 930 for (uint i = 0; i < ParallelGCThreads; i++) { |
| 931 _par_gc_thread_states[i]->promo.reset(); | |
| 932 } | |
| 933 } | |
| 934 } | |
| 935 | |
| 936 void ConcurrentMarkSweepGeneration::space_iterate(SpaceClosure* blk, bool usedOnly) { | |
| 937 blk->do_space(_cmsSpace); | |
| 938 } | |
| 939 | |
| 940 void ConcurrentMarkSweepGeneration::compute_new_size() { | |
| 941 assert_locked_or_safepoint(Heap_lock); | |
| 942 | |
| 943 // If incremental collection failed, we just want to expand | |
| 944 // to the limit. | |
| 945 if (incremental_collection_failed()) { | |
| 946 clear_incremental_collection_failed(); | |
| 947 grow_to_reserved(); | |
| 948 return; | |
| 949 } | |
| 950 | |
| 951 size_t expand_bytes = 0; | |
| 952 double free_percentage = ((double) free()) / capacity(); | |
| 953 double desired_free_percentage = (double) MinHeapFreeRatio / 100; | |
| 954 double maximum_free_percentage = (double) MaxHeapFreeRatio / 100; | |
| 955 | |
| 956 // compute expansion delta needed for reaching desired free percentage | |
| 957 if (free_percentage < desired_free_percentage) { | |
| 958 size_t desired_capacity = (size_t)(used() / ((double) 1 - desired_free_percentage)); | |
| 959 assert(desired_capacity >= capacity(), "invalid expansion size"); | |
| 960 expand_bytes = MAX2(desired_capacity - capacity(), MinHeapDeltaBytes); | |
| 961 } | |
| 962 if (expand_bytes > 0) { | |
| 963 if (PrintGCDetails && Verbose) { | |
| 964 size_t desired_capacity = (size_t)(used() / ((double) 1 - desired_free_percentage)); | |
| 965 gclog_or_tty->print_cr("\nFrom compute_new_size: "); | |
| 966 gclog_or_tty->print_cr(" Free fraction %f", free_percentage); | |
| 967 gclog_or_tty->print_cr(" Desired free fraction %f", | |
| 968 desired_free_percentage); | |
| 969 gclog_or_tty->print_cr(" Maximum free fraction %f", | |
| 970 maximum_free_percentage); | |
| 971 gclog_or_tty->print_cr(" Capactiy "SIZE_FORMAT, capacity()/1000); | |
| 972 gclog_or_tty->print_cr(" Desired capacity "SIZE_FORMAT, | |
| 973 desired_capacity/1000); | |
| 974 int prev_level = level() - 1; | |
| 975 if (prev_level >= 0) { | |
| 976 size_t prev_size = 0; | |
| 977 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 978 Generation* prev_gen = gch->_gens[prev_level]; | |
| 979 prev_size = prev_gen->capacity(); | |
| 980 gclog_or_tty->print_cr(" Younger gen size "SIZE_FORMAT, | |
| 981 prev_size/1000); | |
| 982 } | |
| 983 gclog_or_tty->print_cr(" unsafe_max_alloc_nogc "SIZE_FORMAT, | |
| 984 unsafe_max_alloc_nogc()/1000); | |
| 985 gclog_or_tty->print_cr(" contiguous available "SIZE_FORMAT, | |
| 986 contiguous_available()/1000); | |
| 987 gclog_or_tty->print_cr(" Expand by "SIZE_FORMAT" (bytes)", | |
| 988 expand_bytes); | |
| 989 } | |
| 990 // safe if expansion fails | |
| 991 expand(expand_bytes, 0, CMSExpansionCause::_satisfy_free_ratio); | |
| 992 if (PrintGCDetails && Verbose) { | |
| 993 gclog_or_tty->print_cr(" Expanded free fraction %f", | |
| 994 ((double) free()) / capacity()); | |
| 995 } | |
| 996 } | |
| 997 } | |
| 998 | |
| 999 Mutex* ConcurrentMarkSweepGeneration::freelistLock() const { | |
| 1000 return cmsSpace()->freelistLock(); | |
| 1001 } | |
| 1002 | |
| 1003 HeapWord* ConcurrentMarkSweepGeneration::allocate(size_t size, | |
| 1004 bool tlab) { | |
| 1005 CMSSynchronousYieldRequest yr; | |
| 1006 MutexLockerEx x(freelistLock(), | |
| 1007 Mutex::_no_safepoint_check_flag); | |
| 1008 return have_lock_and_allocate(size, tlab); | |
| 1009 } | |
| 1010 | |
| 1011 HeapWord* ConcurrentMarkSweepGeneration::have_lock_and_allocate(size_t size, | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1012 bool tlab /* ignored */) { |
| 0 | 1013 assert_lock_strong(freelistLock()); |
| 1014 size_t adjustedSize = CompactibleFreeListSpace::adjustObjectSize(size); | |
| 1015 HeapWord* res = cmsSpace()->allocate(adjustedSize); | |
| 1016 // Allocate the object live (grey) if the background collector has | |
| 1017 // started marking. This is necessary because the marker may | |
| 1018 // have passed this address and consequently this object will | |
| 1019 // not otherwise be greyed and would be incorrectly swept up. | |
| 1020 // Note that if this object contains references, the writing | |
| 1021 // of those references will dirty the card containing this object | |
| 1022 // allowing the object to be blackened (and its references scanned) | |
| 1023 // either during a preclean phase or at the final checkpoint. | |
| 1024 if (res != NULL) { | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1025 // We may block here with an uninitialized object with |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1026 // its mark-bit or P-bits not yet set. Such objects need |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1027 // to be safely navigable by block_start(). |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1028 assert(oop(res)->klass_or_null() == NULL, "Object should be uninitialized here."); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1029 assert(!((FreeChunk*)res)->isFree(), "Error, block will look free but show wrong size"); |
| 0 | 1030 collector()->direct_allocated(res, adjustedSize); |
| 1031 _direct_allocated_words += adjustedSize; | |
| 1032 // allocation counters | |
| 1033 NOT_PRODUCT( | |
| 1034 _numObjectsAllocated++; | |
| 1035 _numWordsAllocated += (int)adjustedSize; | |
| 1036 ) | |
| 1037 } | |
| 1038 return res; | |
| 1039 } | |
| 1040 | |
| 1041 // In the case of direct allocation by mutators in a generation that | |
| 1042 // is being concurrently collected, the object must be allocated | |
| 1043 // live (grey) if the background collector has started marking. | |
| 1044 // This is necessary because the marker may | |
| 1045 // have passed this address and consequently this object will | |
| 1046 // not otherwise be greyed and would be incorrectly swept up. | |
| 1047 // Note that if this object contains references, the writing | |
| 1048 // of those references will dirty the card containing this object | |
| 1049 // allowing the object to be blackened (and its references scanned) | |
| 1050 // either during a preclean phase or at the final checkpoint. | |
| 1051 void CMSCollector::direct_allocated(HeapWord* start, size_t size) { | |
| 1052 assert(_markBitMap.covers(start, size), "Out of bounds"); | |
| 1053 if (_collectorState >= Marking) { | |
| 1054 MutexLockerEx y(_markBitMap.lock(), | |
| 1055 Mutex::_no_safepoint_check_flag); | |
| 1056 // [see comments preceding SweepClosure::do_blk() below for details] | |
| 1057 // 1. need to mark the object as live so it isn't collected | |
| 1058 // 2. need to mark the 2nd bit to indicate the object may be uninitialized | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1059 // 3. need to mark the end of the object so marking, precleaning or sweeping |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1060 // can skip over uninitialized or unparsable objects. An allocated |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1061 // object is considered uninitialized for our purposes as long as |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1062 // its klass word is NULL. (Unparsable objects are those which are |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1063 // initialized in the sense just described, but whose sizes can still |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1064 // not be correctly determined. Note that the class of unparsable objects |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1065 // can only occur in the perm gen. All old gen objects are parsable |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1066 // as soon as they are initialized.) |
| 0 | 1067 _markBitMap.mark(start); // object is live |
| 1068 _markBitMap.mark(start + 1); // object is potentially uninitialized? | |
| 1069 _markBitMap.mark(start + size - 1); | |
| 1070 // mark end of object | |
| 1071 } | |
| 1072 // check that oop looks uninitialized | |
| 187 | 1073 assert(oop(start)->klass_or_null() == NULL, "_klass should be NULL"); |
| 0 | 1074 } |
| 1075 | |
| 1076 void CMSCollector::promoted(bool par, HeapWord* start, | |
| 1077 bool is_obj_array, size_t obj_size) { | |
| 1078 assert(_markBitMap.covers(start), "Out of bounds"); | |
| 1079 // See comment in direct_allocated() about when objects should | |
| 1080 // be allocated live. | |
| 1081 if (_collectorState >= Marking) { | |
| 1082 // we already hold the marking bit map lock, taken in | |
| 1083 // the prologue | |
| 1084 if (par) { | |
| 1085 _markBitMap.par_mark(start); | |
| 1086 } else { | |
| 1087 _markBitMap.mark(start); | |
| 1088 } | |
| 1089 // We don't need to mark the object as uninitialized (as | |
| 1090 // in direct_allocated above) because this is being done with the | |
| 1091 // world stopped and the object will be initialized by the | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1092 // time the marking, precleaning or sweeping get to look at it. |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1093 // But see the code for copying objects into the CMS generation, |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1094 // where we need to ensure that concurrent readers of the |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1095 // block offset table are able to safely navigate a block that |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1096 // is in flux from being free to being allocated (and in |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1097 // transition while being copied into) and subsequently |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1098 // becoming a bona-fide object when the copy/promotion is complete. |
| 0 | 1099 assert(SafepointSynchronize::is_at_safepoint(), |
| 1100 "expect promotion only at safepoints"); | |
| 1101 | |
| 1102 if (_collectorState < Sweeping) { | |
| 1103 // Mark the appropriate cards in the modUnionTable, so that | |
| 1104 // this object gets scanned before the sweep. If this is | |
| 1105 // not done, CMS generation references in the object might | |
| 1106 // not get marked. | |
| 1107 // For the case of arrays, which are otherwise precisely | |
| 1108 // marked, we need to dirty the entire array, not just its head. | |
| 1109 if (is_obj_array) { | |
| 1110 // The [par_]mark_range() method expects mr.end() below to | |
| 1111 // be aligned to the granularity of a bit's representation | |
| 1112 // in the heap. In the case of the MUT below, that's a | |
| 1113 // card size. | |
| 1114 MemRegion mr(start, | |
| 1115 (HeapWord*)round_to((intptr_t)(start + obj_size), | |
| 1116 CardTableModRefBS::card_size /* bytes */)); | |
| 1117 if (par) { | |
| 1118 _modUnionTable.par_mark_range(mr); | |
| 1119 } else { | |
| 1120 _modUnionTable.mark_range(mr); | |
| 1121 } | |
| 1122 } else { // not an obj array; we can just mark the head | |
| 1123 if (par) { | |
| 1124 _modUnionTable.par_mark(start); | |
| 1125 } else { | |
| 1126 _modUnionTable.mark(start); | |
| 1127 } | |
| 1128 } | |
| 1129 } | |
| 1130 } | |
| 1131 } | |
| 1132 | |
| 1133 static inline size_t percent_of_space(Space* space, HeapWord* addr) | |
| 1134 { | |
| 1135 size_t delta = pointer_delta(addr, space->bottom()); | |
| 1136 return (size_t)(delta * 100.0 / (space->capacity() / HeapWordSize)); | |
| 1137 } | |
| 1138 | |
| 1139 void CMSCollector::icms_update_allocation_limits() | |
| 1140 { | |
| 1141 Generation* gen0 = GenCollectedHeap::heap()->get_gen(0); | |
| 1142 EdenSpace* eden = gen0->as_DefNewGeneration()->eden(); | |
| 1143 | |
| 1144 const unsigned int duty_cycle = stats().icms_update_duty_cycle(); | |
| 1145 if (CMSTraceIncrementalPacing) { | |
| 1146 stats().print(); | |
| 1147 } | |
| 1148 | |
| 1149 assert(duty_cycle <= 100, "invalid duty cycle"); | |
| 1150 if (duty_cycle != 0) { | |
| 1151 // The duty_cycle is a percentage between 0 and 100; convert to words and | |
| 1152 // then compute the offset from the endpoints of the space. | |
| 1153 size_t free_words = eden->free() / HeapWordSize; | |
| 1154 double free_words_dbl = (double)free_words; | |
| 1155 size_t duty_cycle_words = (size_t)(free_words_dbl * duty_cycle / 100.0); | |
| 1156 size_t offset_words = (free_words - duty_cycle_words) / 2; | |
| 1157 | |
| 1158 _icms_start_limit = eden->top() + offset_words; | |
| 1159 _icms_stop_limit = eden->end() - offset_words; | |
| 1160 | |
| 1161 // The limits may be adjusted (shifted to the right) by | |
| 1162 // CMSIncrementalOffset, to allow the application more mutator time after a | |
| 1163 // young gen gc (when all mutators were stopped) and before CMS starts and | |
| 1164 // takes away one or more cpus. | |
| 1165 if (CMSIncrementalOffset != 0) { | |
| 1166 double adjustment_dbl = free_words_dbl * CMSIncrementalOffset / 100.0; | |
| 1167 size_t adjustment = (size_t)adjustment_dbl; | |
| 1168 HeapWord* tmp_stop = _icms_stop_limit + adjustment; | |
| 1169 if (tmp_stop > _icms_stop_limit && tmp_stop < eden->end()) { | |
| 1170 _icms_start_limit += adjustment; | |
| 1171 _icms_stop_limit = tmp_stop; | |
| 1172 } | |
| 1173 } | |
| 1174 } | |
| 1175 if (duty_cycle == 0 || (_icms_start_limit == _icms_stop_limit)) { | |
| 1176 _icms_start_limit = _icms_stop_limit = eden->end(); | |
| 1177 } | |
| 1178 | |
| 1179 // Install the new start limit. | |
| 1180 eden->set_soft_end(_icms_start_limit); | |
| 1181 | |
| 1182 if (CMSTraceIncrementalMode) { | |
| 1183 gclog_or_tty->print(" icms alloc limits: " | |
| 1184 PTR_FORMAT "," PTR_FORMAT | |
| 1185 " (" SIZE_FORMAT "%%," SIZE_FORMAT "%%) ", | |
| 1186 _icms_start_limit, _icms_stop_limit, | |
| 1187 percent_of_space(eden, _icms_start_limit), | |
| 1188 percent_of_space(eden, _icms_stop_limit)); | |
| 1189 if (Verbose) { | |
| 1190 gclog_or_tty->print("eden: "); | |
| 1191 eden->print_on(gclog_or_tty); | |
| 1192 } | |
| 1193 } | |
| 1194 } | |
| 1195 | |
| 1196 // Any changes here should try to maintain the invariant | |
| 1197 // that if this method is called with _icms_start_limit | |
| 1198 // and _icms_stop_limit both NULL, then it should return NULL | |
| 1199 // and not notify the icms thread. | |
| 1200 HeapWord* | |
| 1201 CMSCollector::allocation_limit_reached(Space* space, HeapWord* top, | |
| 1202 size_t word_size) | |
| 1203 { | |
| 1204 // A start_limit equal to end() means the duty cycle is 0, so treat that as a | |
| 1205 // nop. | |
| 1206 if (CMSIncrementalMode && _icms_start_limit != space->end()) { | |
| 1207 if (top <= _icms_start_limit) { | |
| 1208 if (CMSTraceIncrementalMode) { | |
| 1209 space->print_on(gclog_or_tty); | |
| 1210 gclog_or_tty->stamp(); | |
| 1211 gclog_or_tty->print_cr(" start limit top=" PTR_FORMAT | |
| 1212 ", new limit=" PTR_FORMAT | |
| 1213 " (" SIZE_FORMAT "%%)", | |
| 1214 top, _icms_stop_limit, | |
| 1215 percent_of_space(space, _icms_stop_limit)); | |
| 1216 } | |
| 1217 ConcurrentMarkSweepThread::start_icms(); | |
| 1218 assert(top < _icms_stop_limit, "Tautology"); | |
| 1219 if (word_size < pointer_delta(_icms_stop_limit, top)) { | |
| 1220 return _icms_stop_limit; | |
| 1221 } | |
| 1222 | |
| 1223 // The allocation will cross both the _start and _stop limits, so do the | |
| 1224 // stop notification also and return end(). | |
| 1225 if (CMSTraceIncrementalMode) { | |
| 1226 space->print_on(gclog_or_tty); | |
| 1227 gclog_or_tty->stamp(); | |
| 1228 gclog_or_tty->print_cr(" +stop limit top=" PTR_FORMAT | |
| 1229 ", new limit=" PTR_FORMAT | |
| 1230 " (" SIZE_FORMAT "%%)", | |
| 1231 top, space->end(), | |
| 1232 percent_of_space(space, space->end())); | |
| 1233 } | |
| 1234 ConcurrentMarkSweepThread::stop_icms(); | |
| 1235 return space->end(); | |
| 1236 } | |
| 1237 | |
| 1238 if (top <= _icms_stop_limit) { | |
| 1239 if (CMSTraceIncrementalMode) { | |
| 1240 space->print_on(gclog_or_tty); | |
| 1241 gclog_or_tty->stamp(); | |
| 1242 gclog_or_tty->print_cr(" stop limit top=" PTR_FORMAT | |
| 1243 ", new limit=" PTR_FORMAT | |
| 1244 " (" SIZE_FORMAT "%%)", | |
| 1245 top, space->end(), | |
| 1246 percent_of_space(space, space->end())); | |
| 1247 } | |
| 1248 ConcurrentMarkSweepThread::stop_icms(); | |
| 1249 return space->end(); | |
| 1250 } | |
| 1251 | |
| 1252 if (CMSTraceIncrementalMode) { | |
| 1253 space->print_on(gclog_or_tty); | |
| 1254 gclog_or_tty->stamp(); | |
| 1255 gclog_or_tty->print_cr(" end limit top=" PTR_FORMAT | |
| 1256 ", new limit=" PTR_FORMAT, | |
| 1257 top, NULL); | |
| 1258 } | |
| 1259 } | |
| 1260 | |
| 1261 return NULL; | |
| 1262 } | |
| 1263 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
1264 oop ConcurrentMarkSweepGeneration::promote(oop obj, size_t obj_size) { |
| 0 | 1265 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); |
| 1266 // allocate, copy and if necessary update promoinfo -- | |
| 1267 // delegate to underlying space. | |
| 1268 assert_lock_strong(freelistLock()); | |
| 1269 | |
| 1270 #ifndef PRODUCT | |
| 1271 if (Universe::heap()->promotion_should_fail()) { | |
| 1272 return NULL; | |
| 1273 } | |
| 1274 #endif // #ifndef PRODUCT | |
| 1275 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
1276 oop res = _cmsSpace->promote(obj, obj_size); |
| 0 | 1277 if (res == NULL) { |
| 1278 // expand and retry | |
| 1279 size_t s = _cmsSpace->expansionSpaceRequired(obj_size); // HeapWords | |
| 1280 expand(s*HeapWordSize, MinHeapDeltaBytes, | |
| 1281 CMSExpansionCause::_satisfy_promotion); | |
| 1282 // Since there's currently no next generation, we don't try to promote | |
| 1283 // into a more senior generation. | |
| 1284 assert(next_gen() == NULL, "assumption, based upon which no attempt " | |
| 1285 "is made to pass on a possibly failing " | |
| 1286 "promotion to next generation"); | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
1287 res = _cmsSpace->promote(obj, obj_size); |
| 0 | 1288 } |
| 1289 if (res != NULL) { | |
| 1290 // See comment in allocate() about when objects should | |
| 1291 // be allocated live. | |
| 1292 assert(obj->is_oop(), "Will dereference klass pointer below"); | |
| 1293 collector()->promoted(false, // Not parallel | |
| 1294 (HeapWord*)res, obj->is_objArray(), obj_size); | |
| 1295 // promotion counters | |
| 1296 NOT_PRODUCT( | |
| 1297 _numObjectsPromoted++; | |
| 1298 _numWordsPromoted += | |
| 1299 (int)(CompactibleFreeListSpace::adjustObjectSize(obj->size())); | |
| 1300 ) | |
| 1301 } | |
| 1302 return res; | |
| 1303 } | |
| 1304 | |
| 1305 | |
| 1306 HeapWord* | |
| 1307 ConcurrentMarkSweepGeneration::allocation_limit_reached(Space* space, | |
| 1308 HeapWord* top, | |
| 1309 size_t word_sz) | |
| 1310 { | |
| 1311 return collector()->allocation_limit_reached(space, top, word_sz); | |
| 1312 } | |
| 1313 | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1314 // IMPORTANT: Notes on object size recognition in CMS. |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1315 // --------------------------------------------------- |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1316 // A block of storage in the CMS generation is always in |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1317 // one of three states. A free block (FREE), an allocated |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1318 // object (OBJECT) whose size() method reports the correct size, |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1319 // and an intermediate state (TRANSIENT) in which its size cannot |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1320 // be accurately determined. |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1321 // STATE IDENTIFICATION: (32 bit and 64 bit w/o COOPS) |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1322 // ----------------------------------------------------- |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1323 // FREE: klass_word & 1 == 1; mark_word holds block size |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1324 // |
|
1777
179464550c7d
6983930: CMS: Various small cleanups ca September 2010
ysr
parents:
1720
diff
changeset
|
1325 // OBJECT: klass_word installed; klass_word != 0 && klass_word & 1 == 0; |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1326 // obj->size() computes correct size |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1327 // [Perm Gen objects needs to be "parsable" before they can be navigated] |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1328 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1329 // TRANSIENT: klass_word == 0; size is indeterminate until we become an OBJECT |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1330 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1331 // STATE IDENTIFICATION: (64 bit+COOPS) |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1332 // ------------------------------------ |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1333 // FREE: mark_word & CMS_FREE_BIT == 1; mark_word & ~CMS_FREE_BIT gives block_size |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1334 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1335 // OBJECT: klass_word installed; klass_word != 0; |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1336 // obj->size() computes correct size |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1337 // [Perm Gen comment above continues to hold] |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1338 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1339 // TRANSIENT: klass_word == 0; size is indeterminate until we become an OBJECT |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1340 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1341 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1342 // STATE TRANSITION DIAGRAM |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1343 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1344 // mut / parnew mut / parnew |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1345 // FREE --------------------> TRANSIENT ---------------------> OBJECT --| |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1346 // ^ | |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1347 // |------------------------ DEAD <------------------------------------| |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1348 // sweep mut |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1349 // |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1350 // While a block is in TRANSIENT state its size cannot be determined |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1351 // so readers will either need to come back later or stall until |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1352 // the size can be determined. Note that for the case of direct |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1353 // allocation, P-bits, when available, may be used to determine the |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1354 // size of an object that may not yet have been initialized. |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1355 |
| 0 | 1356 // Things to support parallel young-gen collection. |
| 1357 oop | |
| 1358 ConcurrentMarkSweepGeneration::par_promote(int thread_num, | |
| 1359 oop old, markOop m, | |
| 1360 size_t word_sz) { | |
| 1361 #ifndef PRODUCT | |
| 1362 if (Universe::heap()->promotion_should_fail()) { | |
| 1363 return NULL; | |
| 1364 } | |
| 1365 #endif // #ifndef PRODUCT | |
| 1366 | |
| 1367 CMSParGCThreadState* ps = _par_gc_thread_states[thread_num]; | |
| 1368 PromotionInfo* promoInfo = &ps->promo; | |
| 1369 // if we are tracking promotions, then first ensure space for | |
| 1370 // promotion (including spooling space for saving header if necessary). | |
| 1371 // then allocate and copy, then track promoted info if needed. | |
| 1372 // When tracking (see PromotionInfo::track()), the mark word may | |
| 1373 // be displaced and in this case restoration of the mark word | |
| 1374 // occurs in the (oop_since_save_marks_)iterate phase. | |
| 1375 if (promoInfo->tracking() && !promoInfo->ensure_spooling_space()) { | |
| 1376 // Out of space for allocating spooling buffers; | |
| 1377 // try expanding and allocating spooling buffers. | |
| 1378 if (!expand_and_ensure_spooling_space(promoInfo)) { | |
| 1379 return NULL; | |
| 1380 } | |
| 1381 } | |
| 1382 assert(promoInfo->has_spooling_space(), "Control point invariant"); | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1383 const size_t alloc_sz = CompactibleFreeListSpace::adjustObjectSize(word_sz); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1384 HeapWord* obj_ptr = ps->lab.alloc(alloc_sz); |
| 0 | 1385 if (obj_ptr == NULL) { |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1386 obj_ptr = expand_and_par_lab_allocate(ps, alloc_sz); |
| 0 | 1387 if (obj_ptr == NULL) { |
| 1388 return NULL; | |
| 1389 } | |
| 1390 } | |
| 1391 oop obj = oop(obj_ptr); | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1392 OrderAccess::storestore(); |
| 187 | 1393 assert(obj->klass_or_null() == NULL, "Object should be uninitialized here."); |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1394 assert(!((FreeChunk*)obj_ptr)->isFree(), "Error, block will look free but show wrong size"); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1395 // IMPORTANT: See note on object initialization for CMS above. |
| 0 | 1396 // Otherwise, copy the object. Here we must be careful to insert the |
| 1397 // klass pointer last, since this marks the block as an allocated object. | |
| 187 | 1398 // Except with compressed oops it's the mark word. |
| 0 | 1399 HeapWord* old_ptr = (HeapWord*)old; |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1400 // Restore the mark word copied above. |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1401 obj->set_mark(m); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1402 assert(obj->klass_or_null() == NULL, "Object should be uninitialized here."); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1403 assert(!((FreeChunk*)obj_ptr)->isFree(), "Error, block will look free but show wrong size"); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1404 OrderAccess::storestore(); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1405 |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1406 if (UseCompressedOops) { |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1407 // Copy gap missed by (aligned) header size calculation below |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1408 obj->set_klass_gap(old->klass_gap()); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1409 } |
| 0 | 1410 if (word_sz > (size_t)oopDesc::header_size()) { |
| 1411 Copy::aligned_disjoint_words(old_ptr + oopDesc::header_size(), | |
| 1412 obj_ptr + oopDesc::header_size(), | |
| 1413 word_sz - oopDesc::header_size()); | |
| 1414 } | |
| 187 | 1415 |
| 0 | 1416 // Now we can track the promoted object, if necessary. We take care |
| 1521 | 1417 // to delay the transition from uninitialized to full object |
| 0 | 1418 // (i.e., insertion of klass pointer) until after, so that it |
| 1419 // atomically becomes a promoted object. | |
| 1420 if (promoInfo->tracking()) { | |
| 1421 promoInfo->track((PromotedObject*)obj, old->klass()); | |
| 1422 } | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1423 assert(obj->klass_or_null() == NULL, "Object should be uninitialized here."); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1424 assert(!((FreeChunk*)obj_ptr)->isFree(), "Error, block will look free but show wrong size"); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1425 assert(old->is_oop(), "Will use and dereference old klass ptr below"); |
| 187 | 1426 |
| 1427 // Finally, install the klass pointer (this should be volatile). | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1428 OrderAccess::storestore(); |
| 0 | 1429 obj->set_klass(old->klass()); |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1430 // We should now be able to calculate the right size for this object |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1431 assert(obj->is_oop() && obj->size() == (int)word_sz, "Error, incorrect size computed for promoted object"); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1432 |
| 0 | 1433 collector()->promoted(true, // parallel |
| 1434 obj_ptr, old->is_objArray(), word_sz); | |
| 1435 | |
| 1436 NOT_PRODUCT( | |
|
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1437 Atomic::inc_ptr(&_numObjectsPromoted); |
|
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1704
diff
changeset
|
1438 Atomic::add_ptr(alloc_sz, &_numWordsPromoted); |
| 0 | 1439 ) |
| 1440 | |
| 1441 return obj; | |
| 1442 } | |
| 1443 | |
| 1444 void | |
| 1445 ConcurrentMarkSweepGeneration:: | |
| 1446 par_promote_alloc_undo(int thread_num, | |
| 1447 HeapWord* obj, size_t word_sz) { | |
| 1448 // CMS does not support promotion undo. | |
| 1449 ShouldNotReachHere(); | |
| 1450 } | |
| 1451 | |
| 1452 void | |
| 1453 ConcurrentMarkSweepGeneration:: | |
| 1454 par_promote_alloc_done(int thread_num) { | |
| 1455 CMSParGCThreadState* ps = _par_gc_thread_states[thread_num]; | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
1456 ps->lab.retire(thread_num); |
| 0 | 1457 } |
| 1458 | |
| 1459 void | |
| 1460 ConcurrentMarkSweepGeneration:: | |
| 1461 par_oop_since_save_marks_iterate_done(int thread_num) { | |
| 1462 CMSParGCThreadState* ps = _par_gc_thread_states[thread_num]; | |
| 1463 ParScanWithoutBarrierClosure* dummy_cl = NULL; | |
| 1464 ps->promo.promoted_oops_iterate_nv(dummy_cl); | |
| 1465 } | |
| 1466 | |
| 1467 // XXXPERM | |
| 1468 bool ConcurrentMarkSweepGeneration::should_collect(bool full, | |
| 1469 size_t size, | |
| 1470 bool tlab) | |
| 1471 { | |
| 1472 // We allow a STW collection only if a full | |
| 1473 // collection was requested. | |
| 1474 return full || should_allocate(size, tlab); // FIX ME !!! | |
| 1475 // This and promotion failure handling are connected at the | |
| 1476 // hip and should be fixed by untying them. | |
| 1477 } | |
| 1478 | |
| 1479 bool CMSCollector::shouldConcurrentCollect() { | |
| 1480 if (_full_gc_requested) { | |
| 1481 if (Verbose && PrintGCDetails) { | |
| 1482 gclog_or_tty->print_cr("CMSCollector: collect because of explicit " | |
|
1520
bb843ebc7c55
6919638: CMS: ExplicitGCInvokesConcurrent misinteracts with gc locker
ysr
parents:
1518
diff
changeset
|
1483 " gc request (or gc_locker)"); |
| 0 | 1484 } |
| 1485 return true; | |
| 1486 } | |
| 1487 | |
| 1488 // For debugging purposes, change the type of collection. | |
| 1489 // If the rotation is not on the concurrent collection | |
| 1490 // type, don't start a concurrent collection. | |
| 1491 NOT_PRODUCT( | |
| 1492 if (RotateCMSCollectionTypes && | |
| 1493 (_cmsGen->debug_collection_type() != | |
| 1494 ConcurrentMarkSweepGeneration::Concurrent_collection_type)) { | |
| 1495 assert(_cmsGen->debug_collection_type() != | |
| 1496 ConcurrentMarkSweepGeneration::Unknown_collection_type, | |
| 1497 "Bad cms collection type"); | |
| 1498 return false; | |
| 1499 } | |
| 1500 ) | |
| 1501 | |
| 1502 FreelistLocker x(this); | |
| 1503 // ------------------------------------------------------------------ | |
| 1504 // Print out lots of information which affects the initiation of | |
| 1505 // a collection. | |
| 1506 if (PrintCMSInitiationStatistics && stats().valid()) { | |
| 1507 gclog_or_tty->print("CMSCollector shouldConcurrentCollect: "); | |
| 1508 gclog_or_tty->stamp(); | |
| 1509 gclog_or_tty->print_cr(""); | |
| 1510 stats().print_on(gclog_or_tty); | |
| 1511 gclog_or_tty->print_cr("time_until_cms_gen_full %3.7f", | |
| 1512 stats().time_until_cms_gen_full()); | |
| 1513 gclog_or_tty->print_cr("free="SIZE_FORMAT, _cmsGen->free()); | |
| 1514 gclog_or_tty->print_cr("contiguous_available="SIZE_FORMAT, | |
| 1515 _cmsGen->contiguous_available()); | |
| 1516 gclog_or_tty->print_cr("promotion_rate=%g", stats().promotion_rate()); | |
| 1517 gclog_or_tty->print_cr("cms_allocation_rate=%g", stats().cms_allocation_rate()); | |
| 1518 gclog_or_tty->print_cr("occupancy=%3.7f", _cmsGen->occupancy()); | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1519 gclog_or_tty->print_cr("initiatingOccupancy=%3.7f", _cmsGen->initiating_occupancy()); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1520 gclog_or_tty->print_cr("initiatingPermOccupancy=%3.7f", _permGen->initiating_occupancy()); |
| 0 | 1521 } |
| 1522 // ------------------------------------------------------------------ | |
| 1523 | |
| 1524 // If the estimated time to complete a cms collection (cms_duration()) | |
| 1525 // is less than the estimated time remaining until the cms generation | |
| 1526 // is full, start a collection. | |
| 1527 if (!UseCMSInitiatingOccupancyOnly) { | |
| 1528 if (stats().valid()) { | |
| 1529 if (stats().time_until_cms_start() == 0.0) { | |
| 1530 return true; | |
| 1531 } | |
| 1532 } else { | |
| 1533 // We want to conservatively collect somewhat early in order | |
| 1534 // to try and "bootstrap" our CMS/promotion statistics; | |
| 1535 // this branch will not fire after the first successful CMS | |
| 1536 // collection because the stats should then be valid. | |
| 1537 if (_cmsGen->occupancy() >= _bootstrap_occupancy) { | |
| 1538 if (Verbose && PrintGCDetails) { | |
| 1539 gclog_or_tty->print_cr( | |
| 1540 " CMSCollector: collect for bootstrapping statistics:" | |
| 1541 " occupancy = %f, boot occupancy = %f", _cmsGen->occupancy(), | |
| 1542 _bootstrap_occupancy); | |
| 1543 } | |
| 1544 return true; | |
| 1545 } | |
| 1546 } | |
| 1547 } | |
| 1548 | |
| 1549 // Otherwise, we start a collection cycle if either the perm gen or | |
| 1550 // old gen want a collection cycle started. Each may use | |
| 1551 // an appropriate criterion for making this decision. | |
| 1552 // XXX We need to make sure that the gen expansion | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1553 // criterion dovetails well with this. XXX NEED TO FIX THIS |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1554 if (_cmsGen->should_concurrent_collect()) { |
| 0 | 1555 if (Verbose && PrintGCDetails) { |
| 1556 gclog_or_tty->print_cr("CMS old gen initiated"); | |
| 1557 } | |
| 1558 return true; | |
| 1559 } | |
| 1560 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1561 // We start a collection if we believe an incremental collection may fail; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1562 // this is not likely to be productive in practice because it's probably too |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1563 // late anyway. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1564 GenCollectedHeap* gch = GenCollectedHeap::heap(); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1565 assert(gch->collector_policy()->is_two_generation_policy(), |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1566 "You may want to check the correctness of the following"); |
|
1994
6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
ysr
parents:
1972
diff
changeset
|
1567 if (gch->incremental_collection_will_fail(true /* consult_young */)) { |
|
6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
ysr
parents:
1972
diff
changeset
|
1568 if (Verbose && PrintGCDetails) { |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1569 gclog_or_tty->print("CMSCollector: collect because incremental collection will fail "); |
| 0 | 1570 } |
| 1571 return true; | |
| 1572 } | |
| 1573 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1574 if (CMSClassUnloadingEnabled && _permGen->should_concurrent_collect()) { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1575 bool res = update_should_unload_classes(); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1576 if (res) { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1577 if (Verbose && PrintGCDetails) { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1578 gclog_or_tty->print_cr("CMS perm gen initiated"); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1579 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1580 return true; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1581 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1582 } |
| 0 | 1583 return false; |
| 1584 } | |
| 1585 | |
| 1586 // Clear _expansion_cause fields of constituent generations | |
| 1587 void CMSCollector::clear_expansion_cause() { | |
| 1588 _cmsGen->clear_expansion_cause(); | |
| 1589 _permGen->clear_expansion_cause(); | |
| 1590 } | |
| 1591 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1592 // We should be conservative in starting a collection cycle. To |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1593 // start too eagerly runs the risk of collecting too often in the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1594 // extreme. To collect too rarely falls back on full collections, |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1595 // which works, even if not optimum in terms of concurrent work. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1596 // As a work around for too eagerly collecting, use the flag |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1597 // UseCMSInitiatingOccupancyOnly. This also has the advantage of |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1598 // giving the user an easily understandable way of controlling the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1599 // collections. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1600 // We want to start a new collection cycle if any of the following |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1601 // conditions hold: |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1602 // . our current occupancy exceeds the configured initiating occupancy |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1603 // for this generation, or |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1604 // . we recently needed to expand this space and have not, since that |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1605 // expansion, done a collection of this generation, or |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1606 // . the underlying space believes that it may be a good idea to initiate |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1607 // a concurrent collection (this may be based on criteria such as the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1608 // following: the space uses linear allocation and linear allocation is |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1609 // going to fail, or there is believed to be excessive fragmentation in |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1610 // the generation, etc... or ... |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1611 // [.(currently done by CMSCollector::shouldConcurrentCollect() only for |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1612 // the case of the old generation, not the perm generation; see CR 6543076): |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1613 // we may be approaching a point at which allocation requests may fail because |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1614 // we will be out of sufficient free space given allocation rate estimates.] |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1615 bool ConcurrentMarkSweepGeneration::should_concurrent_collect() const { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1616 |
| 0 | 1617 assert_lock_strong(freelistLock()); |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1618 if (occupancy() > initiating_occupancy()) { |
| 0 | 1619 if (PrintGCDetails && Verbose) { |
| 1620 gclog_or_tty->print(" %s: collect because of occupancy %f / %f ", | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1621 short_name(), occupancy(), initiating_occupancy()); |
| 0 | 1622 } |
| 1623 return true; | |
| 1624 } | |
| 1625 if (UseCMSInitiatingOccupancyOnly) { | |
| 1626 return false; | |
| 1627 } | |
| 1628 if (expansion_cause() == CMSExpansionCause::_satisfy_allocation) { | |
| 1629 if (PrintGCDetails && Verbose) { | |
| 1630 gclog_or_tty->print(" %s: collect because expanded for allocation ", | |
| 1631 short_name()); | |
| 1632 } | |
| 1633 return true; | |
| 1634 } | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1635 if (_cmsSpace->should_concurrent_collect()) { |
| 0 | 1636 if (PrintGCDetails && Verbose) { |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
1637 gclog_or_tty->print(" %s: collect because cmsSpace says so ", |
| 0 | 1638 short_name()); |
| 1639 } | |
| 1640 return true; | |
| 1641 } | |
| 1642 return false; | |
| 1643 } | |
| 1644 | |
| 1645 void ConcurrentMarkSweepGeneration::collect(bool full, | |
| 1646 bool clear_all_soft_refs, | |
| 1647 size_t size, | |
| 1648 bool tlab) | |
| 1649 { | |
| 1650 collector()->collect(full, clear_all_soft_refs, size, tlab); | |
| 1651 } | |
| 1652 | |
| 1653 void CMSCollector::collect(bool full, | |
| 1654 bool clear_all_soft_refs, | |
| 1655 size_t size, | |
| 1656 bool tlab) | |
| 1657 { | |
| 1658 if (!UseCMSCollectionPassing && _collectorState > Idling) { | |
| 1659 // For debugging purposes skip the collection if the state | |
| 1660 // is not currently idle | |
| 1661 if (TraceCMSState) { | |
| 1662 gclog_or_tty->print_cr("Thread " INTPTR_FORMAT " skipped full:%d CMS state %d", | |
| 1663 Thread::current(), full, _collectorState); | |
| 1664 } | |
| 1665 return; | |
| 1666 } | |
| 1667 | |
| 1668 // The following "if" branch is present for defensive reasons. | |
| 1669 // In the current uses of this interface, it can be replaced with: | |
| 1670 // assert(!GC_locker.is_active(), "Can't be called otherwise"); | |
| 1671 // But I am not placing that assert here to allow future | |
| 1672 // generality in invoking this interface. | |
| 1673 if (GC_locker::is_active()) { | |
| 1674 // A consistency test for GC_locker | |
| 1675 assert(GC_locker::needs_gc(), "Should have been set already"); | |
| 1676 // Skip this foreground collection, instead | |
| 1677 // expanding the heap if necessary. | |
| 1678 // Need the free list locks for the call to free() in compute_new_size() | |
| 1679 compute_new_size(); | |
| 1680 return; | |
| 1681 } | |
| 1682 acquire_control_and_collect(full, clear_all_soft_refs); | |
| 1683 _full_gcs_since_conc_gc++; | |
| 1684 | |
| 1685 } | |
| 1686 | |
| 1687 void CMSCollector::request_full_gc(unsigned int full_gc_count) { | |
| 1688 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 1689 unsigned int gc_count = gch->total_full_collections(); | |
| 1690 if (gc_count == full_gc_count) { | |
| 1691 MutexLockerEx y(CGC_lock, Mutex::_no_safepoint_check_flag); | |
| 1692 _full_gc_requested = true; | |
| 1693 CGC_lock->notify(); // nudge CMS thread | |
|
2365
a181f3a124dd
6987703: iCMS: Intermittent hang with gc/gctests/CallGC/CallGC01 and +ExplicitGCInvokesConcurrent
ysr
parents:
2226
diff
changeset
|
1694 } else { |
|
a181f3a124dd
6987703: iCMS: Intermittent hang with gc/gctests/CallGC/CallGC01 and +ExplicitGCInvokesConcurrent
ysr
parents:
2226
diff
changeset
|
1695 assert(gc_count > full_gc_count, "Error: causal loop"); |
| 0 | 1696 } |
| 1697 } | |
| 1698 | |
| 1699 | |
| 1700 // The foreground and background collectors need to coordinate in order | |
| 1701 // to make sure that they do not mutually interfere with CMS collections. | |
| 1702 // When a background collection is active, | |
| 1703 // the foreground collector may need to take over (preempt) and | |
| 1704 // synchronously complete an ongoing collection. Depending on the | |
| 1705 // frequency of the background collections and the heap usage | |
| 1706 // of the application, this preemption can be seldom or frequent. | |
| 1707 // There are only certain | |
| 1708 // points in the background collection that the "collection-baton" | |
| 1709 // can be passed to the foreground collector. | |
| 1710 // | |
| 1711 // The foreground collector will wait for the baton before | |
| 1712 // starting any part of the collection. The foreground collector | |
| 1713 // will only wait at one location. | |
| 1714 // | |
| 1715 // The background collector will yield the baton before starting a new | |
| 1716 // phase of the collection (e.g., before initial marking, marking from roots, | |
| 1717 // precleaning, final re-mark, sweep etc.) This is normally done at the head | |
| 1718 // of the loop which switches the phases. The background collector does some | |
| 1719 // of the phases (initial mark, final re-mark) with the world stopped. | |
| 1720 // Because of locking involved in stopping the world, | |
| 1721 // the foreground collector should not block waiting for the background | |
| 1722 // collector when it is doing a stop-the-world phase. The background | |
| 1723 // collector will yield the baton at an additional point just before | |
| 1724 // it enters a stop-the-world phase. Once the world is stopped, the | |
| 1725 // background collector checks the phase of the collection. If the | |
| 1726 // phase has not changed, it proceeds with the collection. If the | |
| 1727 // phase has changed, it skips that phase of the collection. See | |
| 1728 // the comments on the use of the Heap_lock in collect_in_background(). | |
| 1729 // | |
| 1730 // Variable used in baton passing. | |
| 1731 // _foregroundGCIsActive - Set to true by the foreground collector when | |
| 1732 // it wants the baton. The foreground clears it when it has finished | |
| 1733 // the collection. | |
| 1734 // _foregroundGCShouldWait - Set to true by the background collector | |
| 1735 // when it is running. The foreground collector waits while | |
| 1736 // _foregroundGCShouldWait is true. | |
| 1737 // CGC_lock - monitor used to protect access to the above variables | |
| 1738 // and to notify the foreground and background collectors. | |
| 1739 // _collectorState - current state of the CMS collection. | |
| 1740 // | |
| 1741 // The foreground collector | |
| 1742 // acquires the CGC_lock | |
| 1743 // sets _foregroundGCIsActive | |
| 1744 // waits on the CGC_lock for _foregroundGCShouldWait to be false | |
| 1745 // various locks acquired in preparation for the collection | |
| 1746 // are released so as not to block the background collector | |
| 1747 // that is in the midst of a collection | |
| 1748 // proceeds with the collection | |
| 1749 // clears _foregroundGCIsActive | |
| 1750 // returns | |
| 1751 // | |
| 1752 // The background collector in a loop iterating on the phases of the | |
| 1753 // collection | |
| 1754 // acquires the CGC_lock | |
| 1755 // sets _foregroundGCShouldWait | |
| 1756 // if _foregroundGCIsActive is set | |
| 1757 // clears _foregroundGCShouldWait, notifies _CGC_lock | |
| 1758 // waits on _CGC_lock for _foregroundGCIsActive to become false | |
| 1759 // and exits the loop. | |
| 1760 // otherwise | |
| 1761 // proceed with that phase of the collection | |
| 1762 // if the phase is a stop-the-world phase, | |
| 1763 // yield the baton once more just before enqueueing | |
| 1764 // the stop-world CMS operation (executed by the VM thread). | |
| 1765 // returns after all phases of the collection are done | |
| 1766 // | |
| 1767 | |
| 1768 void CMSCollector::acquire_control_and_collect(bool full, | |
| 1769 bool clear_all_soft_refs) { | |
| 1770 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
| 1771 assert(!Thread::current()->is_ConcurrentGC_thread(), | |
| 1772 "shouldn't try to acquire control from self!"); | |
| 1773 | |
| 1774 // Start the protocol for acquiring control of the | |
| 1775 // collection from the background collector (aka CMS thread). | |
| 1776 assert(ConcurrentMarkSweepThread::vm_thread_has_cms_token(), | |
| 1777 "VM thread should have CMS token"); | |
| 1778 // Remember the possibly interrupted state of an ongoing | |
| 1779 // concurrent collection | |
| 1780 CollectorState first_state = _collectorState; | |
| 1781 | |
| 1782 // Signal to a possibly ongoing concurrent collection that | |
| 1783 // we want to do a foreground collection. | |
| 1784 _foregroundGCIsActive = true; | |
| 1785 | |
| 1786 // Disable incremental mode during a foreground collection. | |
| 1787 ICMSDisabler icms_disabler; | |
| 1788 | |
| 1789 // release locks and wait for a notify from the background collector | |
| 1790 // releasing the locks in only necessary for phases which | |
| 1791 // do yields to improve the granularity of the collection. | |
| 1792 assert_lock_strong(bitMapLock()); | |
| 1793 // We need to lock the Free list lock for the space that we are | |
| 1794 // currently collecting. | |
| 1795 assert(haveFreelistLocks(), "Must be holding free list locks"); | |
| 1796 bitMapLock()->unlock(); | |
| 1797 releaseFreelistLocks(); | |
| 1798 { | |
| 1799 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); | |
| 1800 if (_foregroundGCShouldWait) { | |
| 1801 // We are going to be waiting for action for the CMS thread; | |
| 1802 // it had better not be gone (for instance at shutdown)! | |
| 1803 assert(ConcurrentMarkSweepThread::cmst() != NULL, | |
| 1804 "CMS thread must be running"); | |
| 1805 // Wait here until the background collector gives us the go-ahead | |
| 1806 ConcurrentMarkSweepThread::clear_CMS_flag( | |
| 1807 ConcurrentMarkSweepThread::CMS_vm_has_token); // release token | |
| 1808 // Get a possibly blocked CMS thread going: | |
| 1809 // Note that we set _foregroundGCIsActive true above, | |
| 1810 // without protection of the CGC_lock. | |
| 1811 CGC_lock->notify(); | |
| 1812 assert(!ConcurrentMarkSweepThread::vm_thread_wants_cms_token(), | |
| 1813 "Possible deadlock"); | |
| 1814 while (_foregroundGCShouldWait) { | |
| 1815 // wait for notification | |
| 1816 CGC_lock->wait(Mutex::_no_safepoint_check_flag); | |
| 1817 // Possibility of delay/starvation here, since CMS token does | |
| 1818 // not know to give priority to VM thread? Actually, i think | |
| 1819 // there wouldn't be any delay/starvation, but the proof of | |
| 1820 // that "fact" (?) appears non-trivial. XXX 20011219YSR | |
| 1821 } | |
| 1822 ConcurrentMarkSweepThread::set_CMS_flag( | |
| 1823 ConcurrentMarkSweepThread::CMS_vm_has_token); | |
| 1824 } | |
| 1825 } | |
| 1826 // The CMS_token is already held. Get back the other locks. | |
| 1827 assert(ConcurrentMarkSweepThread::vm_thread_has_cms_token(), | |
| 1828 "VM thread should have CMS token"); | |
| 1829 getFreelistLocks(); | |
| 1830 bitMapLock()->lock_without_safepoint_check(); | |
| 1831 if (TraceCMSState) { | |
| 1832 gclog_or_tty->print_cr("CMS foreground collector has asked for control " | |
| 1833 INTPTR_FORMAT " with first state %d", Thread::current(), first_state); | |
| 1834 gclog_or_tty->print_cr(" gets control with state %d", _collectorState); | |
| 1835 } | |
| 1836 | |
| 1837 // Check if we need to do a compaction, or if not, whether | |
| 1838 // we need to start the mark-sweep from scratch. | |
| 1839 bool should_compact = false; | |
| 1840 bool should_start_over = false; | |
| 1841 decide_foreground_collection_type(clear_all_soft_refs, | |
| 1842 &should_compact, &should_start_over); | |
| 1843 | |
| 1844 NOT_PRODUCT( | |
| 1845 if (RotateCMSCollectionTypes) { | |
| 1846 if (_cmsGen->debug_collection_type() == | |
| 1847 ConcurrentMarkSweepGeneration::MSC_foreground_collection_type) { | |
| 1848 should_compact = true; | |
| 1849 } else if (_cmsGen->debug_collection_type() == | |
| 1850 ConcurrentMarkSweepGeneration::MS_foreground_collection_type) { | |
| 1851 should_compact = false; | |
| 1852 } | |
| 1853 } | |
| 1854 ) | |
| 1855 | |
| 1856 if (PrintGCDetails && first_state > Idling) { | |
| 1857 GCCause::Cause cause = GenCollectedHeap::heap()->gc_cause(); | |
| 1858 if (GCCause::is_user_requested_gc(cause) || | |
| 1859 GCCause::is_serviceability_requested_gc(cause)) { | |
| 1860 gclog_or_tty->print(" (concurrent mode interrupted)"); | |
| 1861 } else { | |
| 1862 gclog_or_tty->print(" (concurrent mode failure)"); | |
| 1863 } | |
| 1864 } | |
| 1865 | |
| 1866 if (should_compact) { | |
| 1867 // If the collection is being acquired from the background | |
| 1868 // collector, there may be references on the discovered | |
| 1869 // references lists that have NULL referents (being those | |
| 1870 // that were concurrently cleared by a mutator) or | |
| 1871 // that are no longer active (having been enqueued concurrently | |
| 1872 // by the mutator). | |
| 1873 // Scrub the list of those references because Mark-Sweep-Compact | |
| 1874 // code assumes referents are not NULL and that all discovered | |
| 1875 // Reference objects are active. | |
| 1876 ref_processor()->clean_up_discovered_references(); | |
| 1877 | |
| 1878 do_compaction_work(clear_all_soft_refs); | |
| 1879 | |
| 1880 // Has the GC time limit been exceeded? | |
|
1387
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1881 DefNewGeneration* young_gen = _young_gen->as_DefNewGeneration(); |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1882 size_t max_eden_size = young_gen->max_capacity() - |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1883 young_gen->to()->capacity() - |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1884 young_gen->from()->capacity(); |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1885 GenCollectedHeap* gch = GenCollectedHeap::heap(); |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1886 GCCause::Cause gc_cause = gch->gc_cause(); |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1887 size_policy()->check_gc_overhead_limit(_young_gen->used(), |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1888 young_gen->eden()->used(), |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1889 _cmsGen->max_capacity(), |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1890 max_eden_size, |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1891 full, |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1892 gc_cause, |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
1893 gch->collector_policy()); |
| 0 | 1894 } else { |
| 1895 do_mark_sweep_work(clear_all_soft_refs, first_state, | |
| 1896 should_start_over); | |
| 1897 } | |
| 1898 // Reset the expansion cause, now that we just completed | |
| 1899 // a collection cycle. | |
| 1900 clear_expansion_cause(); | |
| 1901 _foregroundGCIsActive = false; | |
| 1902 return; | |
| 1903 } | |
| 1904 | |
| 1905 // Resize the perm generation and the tenured generation | |
| 1906 // after obtaining the free list locks for the | |
| 1907 // two generations. | |
| 1908 void CMSCollector::compute_new_size() { | |
| 1909 assert_locked_or_safepoint(Heap_lock); | |
| 1910 FreelistLocker z(this); | |
| 1911 _permGen->compute_new_size(); | |
| 1912 _cmsGen->compute_new_size(); | |
| 1913 } | |
| 1914 | |
| 1915 // A work method used by foreground collection to determine | |
| 1916 // what type of collection (compacting or not, continuing or fresh) | |
| 1917 // it should do. | |
| 1918 // NOTE: the intent is to make UseCMSCompactAtFullCollection | |
| 1919 // and CMSCompactWhenClearAllSoftRefs the default in the future | |
| 1920 // and do away with the flags after a suitable period. | |
| 1921 void CMSCollector::decide_foreground_collection_type( | |
| 1922 bool clear_all_soft_refs, bool* should_compact, | |
| 1923 bool* should_start_over) { | |
| 1924 // Normally, we'll compact only if the UseCMSCompactAtFullCollection | |
| 1925 // flag is set, and we have either requested a System.gc() or | |
| 1926 // the number of full gc's since the last concurrent cycle | |
| 1927 // has exceeded the threshold set by CMSFullGCsBeforeCompaction, | |
| 1928 // or if an incremental collection has failed | |
| 1929 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 1930 assert(gch->collector_policy()->is_two_generation_policy(), | |
| 1931 "You may want to check the correctness of the following"); | |
| 1932 // Inform cms gen if this was due to partial collection failing. | |
| 1933 // The CMS gen may use this fact to determine its expansion policy. | |
|
1994
6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
ysr
parents:
1972
diff
changeset
|
1934 if (gch->incremental_collection_will_fail(false /* don't consult_young */)) { |
| 0 | 1935 assert(!_cmsGen->incremental_collection_failed(), |
| 1936 "Should have been noticed, reacted to and cleared"); | |
| 1937 _cmsGen->set_incremental_collection_failed(); | |
| 1938 } | |
| 1939 *should_compact = | |
| 1940 UseCMSCompactAtFullCollection && | |
| 1941 ((_full_gcs_since_conc_gc >= CMSFullGCsBeforeCompaction) || | |
| 1942 GCCause::is_user_requested_gc(gch->gc_cause()) || | |
|
1994
6cd6d394f280
7001033: assert(gch->gc_cause() == GCCause::_scavenge_alot || !gch->incremental_collection_failed())
ysr
parents:
1972
diff
changeset
|
1943 gch->incremental_collection_will_fail(true /* consult_young */)); |
| 0 | 1944 *should_start_over = false; |
| 1945 if (clear_all_soft_refs && !*should_compact) { | |
| 1946 // We are about to do a last ditch collection attempt | |
| 1947 // so it would normally make sense to do a compaction | |
| 1948 // to reclaim as much space as possible. | |
| 1949 if (CMSCompactWhenClearAllSoftRefs) { | |
| 1950 // Default: The rationale is that in this case either | |
| 1951 // we are past the final marking phase, in which case | |
| 1952 // we'd have to start over, or so little has been done | |
| 1953 // that there's little point in saving that work. Compaction | |
| 1954 // appears to be the sensible choice in either case. | |
| 1955 *should_compact = true; | |
| 1956 } else { | |
| 1957 // We have been asked to clear all soft refs, but not to | |
| 1958 // compact. Make sure that we aren't past the final checkpoint | |
| 1959 // phase, for that is where we process soft refs. If we are already | |
| 1960 // past that phase, we'll need to redo the refs discovery phase and | |
| 1961 // if necessary clear soft refs that weren't previously | |
| 1962 // cleared. We do so by remembering the phase in which | |
| 1963 // we came in, and if we are past the refs processing | |
| 1964 // phase, we'll choose to just redo the mark-sweep | |
| 1965 // collection from scratch. | |
| 1966 if (_collectorState > FinalMarking) { | |
| 1967 // We are past the refs processing phase; | |
| 1968 // start over and do a fresh synchronous CMS cycle | |
| 1969 _collectorState = Resetting; // skip to reset to start new cycle | |
| 1970 reset(false /* == !asynch */); | |
| 1971 *should_start_over = true; | |
| 1972 } // else we can continue a possibly ongoing current cycle | |
| 1973 } | |
| 1974 } | |
| 1975 } | |
| 1976 | |
| 1977 // A work method used by the foreground collector to do | |
| 1978 // a mark-sweep-compact. | |
| 1979 void CMSCollector::do_compaction_work(bool clear_all_soft_refs) { | |
| 1980 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 1981 TraceTime t("CMS:MSC ", PrintGCDetails && Verbose, true, gclog_or_tty); | |
| 1982 if (PrintGC && Verbose && !(GCCause::is_user_requested_gc(gch->gc_cause()))) { | |
| 1983 gclog_or_tty->print_cr("Compact ConcurrentMarkSweepGeneration after %d " | |
| 1984 "collections passed to foreground collector", _full_gcs_since_conc_gc); | |
| 1985 } | |
| 1986 | |
| 1987 // Sample collection interval time and reset for collection pause. | |
| 1988 if (UseAdaptiveSizePolicy) { | |
| 1989 size_policy()->msc_collection_begin(); | |
| 1990 } | |
| 1991 | |
| 1992 // Temporarily widen the span of the weak reference processing to | |
| 1993 // the entire heap. | |
| 1994 MemRegion new_span(GenCollectedHeap::heap()->reserved_region()); | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
1995 ReferenceProcessorSpanMutator rp_mut_span(ref_processor(), new_span); |
| 0 | 1996 // Temporarily, clear the "is_alive_non_header" field of the |
| 1997 // reference processor. | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
1998 ReferenceProcessorIsAliveMutator rp_mut_closure(ref_processor(), NULL); |
| 0 | 1999 // Temporarily make reference _processing_ single threaded (non-MT). |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
2000 ReferenceProcessorMTProcMutator rp_mut_mt_processing(ref_processor(), false); |
| 0 | 2001 // Temporarily make refs discovery atomic |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
2002 ReferenceProcessorAtomicMutator rp_mut_atomic(ref_processor(), true); |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
2003 // Temporarily make reference _discovery_ single threaded (non-MT) |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
2004 ReferenceProcessorMTDiscoveryMutator rp_mut_discovery(ref_processor(), false); |
| 0 | 2005 |
| 2006 ref_processor()->set_enqueuing_is_done(false); | |
|
3979
4dfb2df418f2
6484982: G1: process references during evacuation pauses
johnc
parents:
3827
diff
changeset
|
2007 ref_processor()->enable_discovery(false /*verify_disabled*/, false /*check_no_refs*/); |
|
457
27a80744a83b
6778647: snap(), snap_policy() should be renamed setup(), setup_policy()
ysr
parents:
453
diff
changeset
|
2008 ref_processor()->setup_policy(clear_all_soft_refs); |
| 0 | 2009 // If an asynchronous collection finishes, the _modUnionTable is |
| 2010 // all clear. If we are assuming the collection from an asynchronous | |
| 2011 // collection, clear the _modUnionTable. | |
| 2012 assert(_collectorState != Idling || _modUnionTable.isAllClear(), | |
| 2013 "_modUnionTable should be clear if the baton was not passed"); | |
| 2014 _modUnionTable.clear_all(); | |
| 2015 | |
| 2016 // We must adjust the allocation statistics being maintained | |
| 2017 // in the free list space. We do so by reading and clearing | |
| 2018 // the sweep timer and updating the block flux rate estimates below. | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2019 assert(!_intra_sweep_timer.is_active(), "_intra_sweep_timer should be inactive"); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2020 if (_inter_sweep_timer.is_active()) { |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2021 _inter_sweep_timer.stop(); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2022 // Note that we do not use this sample to update the _inter_sweep_estimate. |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2023 _cmsGen->cmsSpace()->beginSweepFLCensus((float)(_inter_sweep_timer.seconds()), |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2024 _inter_sweep_estimate.padded_average(), |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2025 _intra_sweep_estimate.padded_average()); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2026 } |
| 0 | 2027 |
| 2028 GenMarkSweep::invoke_at_safepoint(_cmsGen->level(), | |
| 2029 ref_processor(), clear_all_soft_refs); | |
| 2030 #ifdef ASSERT | |
| 2031 CompactibleFreeListSpace* cms_space = _cmsGen->cmsSpace(); | |
| 2032 size_t free_size = cms_space->free(); | |
| 2033 assert(free_size == | |
| 2034 pointer_delta(cms_space->end(), cms_space->compaction_top()) | |
| 2035 * HeapWordSize, | |
| 2036 "All the free space should be compacted into one chunk at top"); | |
| 2037 assert(cms_space->dictionary()->totalChunkSize( | |
| 2038 debug_only(cms_space->freelistLock())) == 0 || | |
| 2039 cms_space->totalSizeInIndexedFreeLists() == 0, | |
| 2040 "All the free space should be in a single chunk"); | |
| 2041 size_t num = cms_space->totalCount(); | |
| 2042 assert((free_size == 0 && num == 0) || | |
| 2043 (free_size > 0 && (num == 1 || num == 2)), | |
| 2044 "There should be at most 2 free chunks after compaction"); | |
| 2045 #endif // ASSERT | |
| 2046 _collectorState = Resetting; | |
| 2047 assert(_restart_addr == NULL, | |
| 2048 "Should have been NULL'd before baton was passed"); | |
| 2049 reset(false /* == !asynch */); | |
| 2050 _cmsGen->reset_after_compaction(); | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2051 _concurrent_cycles_since_last_unload = 0; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2052 |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2053 if (verifying() && !should_unload_classes()) { |
| 0 | 2054 perm_gen_verify_bit_map()->clear_all(); |
| 2055 } | |
| 2056 | |
| 2057 // Clear any data recorded in the PLAB chunk arrays. | |
| 2058 if (_survivor_plab_array != NULL) { | |
| 2059 reset_survivor_plab_arrays(); | |
| 2060 } | |
| 2061 | |
| 2062 // Adjust the per-size allocation stats for the next epoch. | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2063 _cmsGen->cmsSpace()->endSweepFLCensus(sweep_count() /* fake */); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2064 // Restart the "inter sweep timer" for the next epoch. |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2065 _inter_sweep_timer.reset(); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2066 _inter_sweep_timer.start(); |
| 0 | 2067 |
| 2068 // Sample collection pause time and reset for collection interval. | |
| 2069 if (UseAdaptiveSizePolicy) { | |
| 2070 size_policy()->msc_collection_end(gch->gc_cause()); | |
| 2071 } | |
| 2072 | |
| 2073 // For a mark-sweep-compact, compute_new_size() will be called | |
| 2074 // in the heap's do_collection() method. | |
| 2075 } | |
| 2076 | |
| 2077 // A work method used by the foreground collector to do | |
| 2078 // a mark-sweep, after taking over from a possibly on-going | |
| 2079 // concurrent mark-sweep collection. | |
| 2080 void CMSCollector::do_mark_sweep_work(bool clear_all_soft_refs, | |
| 2081 CollectorState first_state, bool should_start_over) { | |
| 2082 if (PrintGC && Verbose) { | |
| 2083 gclog_or_tty->print_cr("Pass concurrent collection to foreground " | |
| 2084 "collector with count %d", | |
| 2085 _full_gcs_since_conc_gc); | |
| 2086 } | |
| 2087 switch (_collectorState) { | |
| 2088 case Idling: | |
| 2089 if (first_state == Idling || should_start_over) { | |
| 2090 // The background GC was not active, or should | |
| 2091 // restarted from scratch; start the cycle. | |
| 2092 _collectorState = InitialMarking; | |
| 2093 } | |
| 2094 // If first_state was not Idling, then a background GC | |
| 2095 // was in progress and has now finished. No need to do it | |
| 2096 // again. Leave the state as Idling. | |
| 2097 break; | |
| 2098 case Precleaning: | |
| 2099 // In the foreground case don't do the precleaning since | |
| 2100 // it is not done concurrently and there is extra work | |
| 2101 // required. | |
| 2102 _collectorState = FinalMarking; | |
| 2103 } | |
| 2104 if (PrintGCDetails && | |
| 2105 (_collectorState > Idling || | |
| 2106 !GCCause::is_user_requested_gc(GenCollectedHeap::heap()->gc_cause()))) { | |
| 2107 gclog_or_tty->print(" (concurrent mode failure)"); | |
| 2108 } | |
| 2109 collect_in_foreground(clear_all_soft_refs); | |
| 2110 | |
| 2111 // For a mark-sweep, compute_new_size() will be called | |
| 2112 // in the heap's do_collection() method. | |
| 2113 } | |
| 2114 | |
| 2115 | |
| 2116 void CMSCollector::getFreelistLocks() const { | |
| 2117 // Get locks for all free lists in all generations that this | |
| 2118 // collector is responsible for | |
| 2119 _cmsGen->freelistLock()->lock_without_safepoint_check(); | |
| 2120 _permGen->freelistLock()->lock_without_safepoint_check(); | |
| 2121 } | |
| 2122 | |
| 2123 void CMSCollector::releaseFreelistLocks() const { | |
| 2124 // Release locks for all free lists in all generations that this | |
| 2125 // collector is responsible for | |
| 2126 _cmsGen->freelistLock()->unlock(); | |
| 2127 _permGen->freelistLock()->unlock(); | |
| 2128 } | |
| 2129 | |
| 2130 bool CMSCollector::haveFreelistLocks() const { | |
| 2131 // Check locks for all free lists in all generations that this | |
| 2132 // collector is responsible for | |
| 2133 assert_lock_strong(_cmsGen->freelistLock()); | |
| 2134 assert_lock_strong(_permGen->freelistLock()); | |
| 2135 PRODUCT_ONLY(ShouldNotReachHere()); | |
| 2136 return true; | |
| 2137 } | |
| 2138 | |
| 2139 // A utility class that is used by the CMS collector to | |
| 2140 // temporarily "release" the foreground collector from its | |
| 2141 // usual obligation to wait for the background collector to | |
| 2142 // complete an ongoing phase before proceeding. | |
| 2143 class ReleaseForegroundGC: public StackObj { | |
| 2144 private: | |
| 2145 CMSCollector* _c; | |
| 2146 public: | |
| 2147 ReleaseForegroundGC(CMSCollector* c) : _c(c) { | |
| 2148 assert(_c->_foregroundGCShouldWait, "Else should not need to call"); | |
| 2149 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); | |
| 2150 // allow a potentially blocked foreground collector to proceed | |
| 2151 _c->_foregroundGCShouldWait = false; | |
| 2152 if (_c->_foregroundGCIsActive) { | |
| 2153 CGC_lock->notify(); | |
| 2154 } | |
| 2155 assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 2156 "Possible deadlock"); | |
| 2157 } | |
| 2158 | |
| 2159 ~ReleaseForegroundGC() { | |
| 2160 assert(!_c->_foregroundGCShouldWait, "Usage protocol violation?"); | |
| 2161 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); | |
| 2162 _c->_foregroundGCShouldWait = true; | |
| 2163 } | |
| 2164 }; | |
| 2165 | |
| 2166 // There are separate collect_in_background and collect_in_foreground because of | |
| 2167 // the different locking requirements of the background collector and the | |
| 2168 // foreground collector. There was originally an attempt to share | |
| 2169 // one "collect" method between the background collector and the foreground | |
| 2170 // collector but the if-then-else required made it cleaner to have | |
| 2171 // separate methods. | |
| 2172 void CMSCollector::collect_in_background(bool clear_all_soft_refs) { | |
| 2173 assert(Thread::current()->is_ConcurrentGC_thread(), | |
| 2174 "A CMS asynchronous collection is only allowed on a CMS thread."); | |
| 2175 | |
| 2176 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 2177 { | |
| 2178 bool safepoint_check = Mutex::_no_safepoint_check_flag; | |
| 2179 MutexLockerEx hl(Heap_lock, safepoint_check); | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2180 FreelistLocker fll(this); |
| 0 | 2181 MutexLockerEx x(CGC_lock, safepoint_check); |
| 2182 if (_foregroundGCIsActive || !UseAsyncConcMarkSweepGC) { | |
| 2183 // The foreground collector is active or we're | |
| 2184 // not using asynchronous collections. Skip this | |
| 2185 // background collection. | |
| 2186 assert(!_foregroundGCShouldWait, "Should be clear"); | |
| 2187 return; | |
| 2188 } else { | |
| 2189 assert(_collectorState == Idling, "Should be idling before start."); | |
| 2190 _collectorState = InitialMarking; | |
| 2191 // Reset the expansion cause, now that we are about to begin | |
| 2192 // a new cycle. | |
| 2193 clear_expansion_cause(); | |
| 2194 } | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2195 // Decide if we want to enable class unloading as part of the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2196 // ensuing concurrent GC cycle. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
2197 update_should_unload_classes(); |
| 0 | 2198 _full_gc_requested = false; // acks all outstanding full gc requests |
| 2199 // Signal that we are about to start a collection | |
| 2200 gch->increment_total_full_collections(); // ... starting a collection cycle | |
| 2201 _collection_count_start = gch->total_full_collections(); | |
| 2202 } | |
| 2203 | |
| 2204 // Used for PrintGC | |
| 2205 size_t prev_used; | |
| 2206 if (PrintGC && Verbose) { | |
| 2207 prev_used = _cmsGen->used(); // XXXPERM | |
| 2208 } | |
| 2209 | |
| 2210 // The change of the collection state is normally done at this level; | |
| 2211 // the exceptions are phases that are executed while the world is | |
| 2212 // stopped. For those phases the change of state is done while the | |
| 2213 // world is stopped. For baton passing purposes this allows the | |
| 2214 // background collector to finish the phase and change state atomically. | |
| 2215 // The foreground collector cannot wait on a phase that is done | |
| 2216 // while the world is stopped because the foreground collector already | |
| 2217 // has the world stopped and would deadlock. | |
| 2218 while (_collectorState != Idling) { | |
| 2219 if (TraceCMSState) { | |
| 2220 gclog_or_tty->print_cr("Thread " INTPTR_FORMAT " in CMS state %d", | |
| 2221 Thread::current(), _collectorState); | |
| 2222 } | |
| 2223 // The foreground collector | |
| 2224 // holds the Heap_lock throughout its collection. | |
| 2225 // holds the CMS token (but not the lock) | |
| 2226 // except while it is waiting for the background collector to yield. | |
| 2227 // | |
| 2228 // The foreground collector should be blocked (not for long) | |
| 2229 // if the background collector is about to start a phase | |
| 2230 // executed with world stopped. If the background | |
| 2231 // collector has already started such a phase, the | |
| 2232 // foreground collector is blocked waiting for the | |
| 2233 // Heap_lock. The stop-world phases (InitialMarking and FinalMarking) | |
| 2234 // are executed in the VM thread. | |
| 2235 // | |
| 2236 // The locking order is | |
| 2237 // PendingListLock (PLL) -- if applicable (FinalMarking) | |
| 2238 // Heap_lock (both this & PLL locked in VM_CMS_Operation::prologue()) | |
| 2239 // CMS token (claimed in | |
| 2240 // stop_world_and_do() --> | |
| 2241 // safepoint_synchronize() --> | |
| 2242 // CMSThread::synchronize()) | |
| 2243 | |
| 2244 { | |
| 2245 // Check if the FG collector wants us to yield. | |
| 2246 CMSTokenSync x(true); // is cms thread | |
| 2247 if (waitForForegroundGC()) { | |
| 2248 // We yielded to a foreground GC, nothing more to be | |
| 2249 // done this round. | |
| 2250 assert(_foregroundGCShouldWait == false, "We set it to false in " | |
| 2251 "waitForForegroundGC()"); | |
| 2252 if (TraceCMSState) { | |
| 2253 gclog_or_tty->print_cr("CMS Thread " INTPTR_FORMAT | |
| 2254 " exiting collection CMS state %d", | |
| 2255 Thread::current(), _collectorState); | |
| 2256 } | |
| 2257 return; | |
| 2258 } else { | |
| 2259 // The background collector can run but check to see if the | |
| 2260 // foreground collector has done a collection while the | |
| 2261 // background collector was waiting to get the CGC_lock | |
| 2262 // above. If yes, break so that _foregroundGCShouldWait | |
| 2263 // is cleared before returning. | |
| 2264 if (_collectorState == Idling) { | |
| 2265 break; | |
| 2266 } | |
| 2267 } | |
| 2268 } | |
| 2269 | |
| 2270 assert(_foregroundGCShouldWait, "Foreground collector, if active, " | |
| 2271 "should be waiting"); | |
| 2272 | |
| 2273 switch (_collectorState) { | |
| 2274 case InitialMarking: | |
| 2275 { | |
| 2276 ReleaseForegroundGC x(this); | |
| 2277 stats().record_cms_begin(); | |
| 2278 | |
| 2279 VM_CMS_Initial_Mark initial_mark_op(this); | |
| 2280 VMThread::execute(&initial_mark_op); | |
| 2281 } | |
| 2282 // The collector state may be any legal state at this point | |
| 2283 // since the background collector may have yielded to the | |
| 2284 // foreground collector. | |
| 2285 break; | |
| 2286 case Marking: | |
| 2287 // initial marking in checkpointRootsInitialWork has been completed | |
| 2288 if (markFromRoots(true)) { // we were successful | |
| 2289 assert(_collectorState == Precleaning, "Collector state should " | |
| 2290 "have changed"); | |
| 2291 } else { | |
| 2292 assert(_foregroundGCIsActive, "Internal state inconsistency"); | |
| 2293 } | |
| 2294 break; | |
| 2295 case Precleaning: | |
| 2296 if (UseAdaptiveSizePolicy) { | |
| 2297 size_policy()->concurrent_precleaning_begin(); | |
| 2298 } | |
| 2299 // marking from roots in markFromRoots has been completed | |
| 2300 preclean(); | |
| 2301 if (UseAdaptiveSizePolicy) { | |
| 2302 size_policy()->concurrent_precleaning_end(); | |
| 2303 } | |
| 2304 assert(_collectorState == AbortablePreclean || | |
| 2305 _collectorState == FinalMarking, | |
| 2306 "Collector state should have changed"); | |
| 2307 break; | |
| 2308 case AbortablePreclean: | |
| 2309 if (UseAdaptiveSizePolicy) { | |
| 2310 size_policy()->concurrent_phases_resume(); | |
| 2311 } | |
| 2312 abortable_preclean(); | |
| 2313 if (UseAdaptiveSizePolicy) { | |
| 2314 size_policy()->concurrent_precleaning_end(); | |
| 2315 } | |
| 2316 assert(_collectorState == FinalMarking, "Collector state should " | |
| 2317 "have changed"); | |
| 2318 break; | |
| 2319 case FinalMarking: | |
| 2320 { | |
| 2321 ReleaseForegroundGC x(this); | |
| 2322 | |
| 2323 VM_CMS_Final_Remark final_remark_op(this); | |
| 2324 VMThread::execute(&final_remark_op); | |
| 935 | 2325 } |
| 0 | 2326 assert(_foregroundGCShouldWait, "block post-condition"); |
| 2327 break; | |
| 2328 case Sweeping: | |
| 2329 if (UseAdaptiveSizePolicy) { | |
| 2330 size_policy()->concurrent_sweeping_begin(); | |
| 2331 } | |
| 2332 // final marking in checkpointRootsFinal has been completed | |
| 2333 sweep(true); | |
| 2334 assert(_collectorState == Resizing, "Collector state change " | |
| 2335 "to Resizing must be done under the free_list_lock"); | |
| 2336 _full_gcs_since_conc_gc = 0; | |
| 2337 | |
| 2338 // Stop the timers for adaptive size policy for the concurrent phases | |
| 2339 if (UseAdaptiveSizePolicy) { | |
| 2340 size_policy()->concurrent_sweeping_end(); | |
| 2341 size_policy()->concurrent_phases_end(gch->gc_cause(), | |
| 2342 gch->prev_gen(_cmsGen)->capacity(), | |
| 2343 _cmsGen->free()); | |
| 2344 } | |
| 2345 | |
| 2346 case Resizing: { | |
| 2347 // Sweeping has been completed... | |
| 2348 // At this point the background collection has completed. | |
| 2349 // Don't move the call to compute_new_size() down | |
| 2350 // into code that might be executed if the background | |
| 2351 // collection was preempted. | |
| 2352 { | |
| 2353 ReleaseForegroundGC x(this); // unblock FG collection | |
| 2354 MutexLockerEx y(Heap_lock, Mutex::_no_safepoint_check_flag); | |
| 2355 CMSTokenSync z(true); // not strictly needed. | |
| 2356 if (_collectorState == Resizing) { | |
| 2357 compute_new_size(); | |
| 2358 _collectorState = Resetting; | |
| 2359 } else { | |
| 2360 assert(_collectorState == Idling, "The state should only change" | |
| 2361 " because the foreground collector has finished the collection"); | |
| 2362 } | |
| 2363 } | |
| 2364 break; | |
| 2365 } | |
| 2366 case Resetting: | |
| 2367 // CMS heap resizing has been completed | |
| 2368 reset(true); | |
| 2369 assert(_collectorState == Idling, "Collector state should " | |
| 2370 "have changed"); | |
| 2371 stats().record_cms_end(); | |
| 2372 // Don't move the concurrent_phases_end() and compute_new_size() | |
| 2373 // calls to here because a preempted background collection | |
| 2374 // has it's state set to "Resetting". | |
| 2375 break; | |
| 2376 case Idling: | |
| 2377 default: | |
| 2378 ShouldNotReachHere(); | |
| 2379 break; | |
| 2380 } | |
| 2381 if (TraceCMSState) { | |
| 2382 gclog_or_tty->print_cr(" Thread " INTPTR_FORMAT " done - next CMS state %d", | |
| 2383 Thread::current(), _collectorState); | |
| 2384 } | |
| 2385 assert(_foregroundGCShouldWait, "block post-condition"); | |
| 2386 } | |
| 2387 | |
| 2388 // Should this be in gc_epilogue? | |
| 2389 collector_policy()->counters()->update_counters(); | |
| 2390 | |
| 2391 { | |
| 2392 // Clear _foregroundGCShouldWait and, in the event that the | |
| 2393 // foreground collector is waiting, notify it, before | |
| 2394 // returning. | |
| 2395 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); | |
| 2396 _foregroundGCShouldWait = false; | |
| 2397 if (_foregroundGCIsActive) { | |
| 2398 CGC_lock->notify(); | |
| 2399 } | |
| 2400 assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 2401 "Possible deadlock"); | |
| 2402 } | |
| 2403 if (TraceCMSState) { | |
| 2404 gclog_or_tty->print_cr("CMS Thread " INTPTR_FORMAT | |
| 2405 " exiting collection CMS state %d", | |
| 2406 Thread::current(), _collectorState); | |
| 2407 } | |
| 2408 if (PrintGC && Verbose) { | |
| 2409 _cmsGen->print_heap_change(prev_used); | |
| 2410 } | |
| 2411 } | |
| 2412 | |
| 2413 void CMSCollector::collect_in_foreground(bool clear_all_soft_refs) { | |
| 2414 assert(_foregroundGCIsActive && !_foregroundGCShouldWait, | |
| 2415 "Foreground collector should be waiting, not executing"); | |
| 2416 assert(Thread::current()->is_VM_thread(), "A foreground collection" | |
| 2417 "may only be done by the VM Thread with the world stopped"); | |
| 2418 assert(ConcurrentMarkSweepThread::vm_thread_has_cms_token(), | |
| 2419 "VM thread should have CMS token"); | |
| 2420 | |
| 2421 NOT_PRODUCT(TraceTime t("CMS:MS (foreground) ", PrintGCDetails && Verbose, | |
| 2422 true, gclog_or_tty);) | |
| 2423 if (UseAdaptiveSizePolicy) { | |
| 2424 size_policy()->ms_collection_begin(); | |
| 2425 } | |
| 2426 COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact); | |
| 2427 | |
| 2428 HandleMark hm; // Discard invalid handles created during verification | |
| 2429 | |
| 2430 if (VerifyBeforeGC && | |
| 2431 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 2432 Universe::verify(true); | |
| 2433 } | |
| 2434 | |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
2435 // Snapshot the soft reference policy to be used in this collection cycle. |
|
457
27a80744a83b
6778647: snap(), snap_policy() should be renamed setup(), setup_policy()
ysr
parents:
453
diff
changeset
|
2436 ref_processor()->setup_policy(clear_all_soft_refs); |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
2437 |
| 0 | 2438 bool init_mark_was_synchronous = false; // until proven otherwise |
| 2439 while (_collectorState != Idling) { | |
| 2440 if (TraceCMSState) { | |
| 2441 gclog_or_tty->print_cr("Thread " INTPTR_FORMAT " in CMS state %d", | |
| 2442 Thread::current(), _collectorState); | |
| 2443 } | |
| 2444 switch (_collectorState) { | |
| 2445 case InitialMarking: | |
| 2446 init_mark_was_synchronous = true; // fact to be exploited in re-mark | |
| 2447 checkpointRootsInitial(false); | |
| 2448 assert(_collectorState == Marking, "Collector state should have changed" | |
| 2449 " within checkpointRootsInitial()"); | |
| 2450 break; | |
| 2451 case Marking: | |
| 2452 // initial marking in checkpointRootsInitialWork has been completed | |
| 2453 if (VerifyDuringGC && | |
| 2454 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 2455 gclog_or_tty->print("Verify before initial mark: "); | |
| 2456 Universe::verify(true); | |
| 2457 } | |
| 2458 { | |
| 2459 bool res = markFromRoots(false); | |
| 2460 assert(res && _collectorState == FinalMarking, "Collector state should " | |
| 2461 "have changed"); | |
| 2462 break; | |
| 2463 } | |
| 2464 case FinalMarking: | |
| 2465 if (VerifyDuringGC && | |
| 2466 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 2467 gclog_or_tty->print("Verify before re-mark: "); | |
| 2468 Universe::verify(true); | |
| 2469 } | |
| 2470 checkpointRootsFinal(false, clear_all_soft_refs, | |
| 2471 init_mark_was_synchronous); | |
| 2472 assert(_collectorState == Sweeping, "Collector state should not " | |
| 2473 "have changed within checkpointRootsFinal()"); | |
| 2474 break; | |
| 2475 case Sweeping: | |
| 2476 // final marking in checkpointRootsFinal has been completed | |
| 2477 if (VerifyDuringGC && | |
| 2478 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 2479 gclog_or_tty->print("Verify before sweep: "); | |
| 2480 Universe::verify(true); | |
| 2481 } | |
| 2482 sweep(false); | |
| 2483 assert(_collectorState == Resizing, "Incorrect state"); | |
| 2484 break; | |
| 2485 case Resizing: { | |
| 2486 // Sweeping has been completed; the actual resize in this case | |
| 2487 // is done separately; nothing to be done in this state. | |
| 2488 _collectorState = Resetting; | |
| 2489 break; | |
| 2490 } | |
| 2491 case Resetting: | |
| 2492 // The heap has been resized. | |
| 2493 if (VerifyDuringGC && | |
| 2494 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 2495 gclog_or_tty->print("Verify before reset: "); | |
| 2496 Universe::verify(true); | |
| 2497 } | |
| 2498 reset(false); | |
| 2499 assert(_collectorState == Idling, "Collector state should " | |
| 2500 "have changed"); | |
| 2501 break; | |
| 2502 case Precleaning: | |
| 2503 case AbortablePreclean: | |
| 2504 // Elide the preclean phase | |
| 2505 _collectorState = FinalMarking; | |
| 2506 break; | |
| 2507 default: | |
| 2508 ShouldNotReachHere(); | |
| 2509 } | |
| 2510 if (TraceCMSState) { | |
| 2511 gclog_or_tty->print_cr(" Thread " INTPTR_FORMAT " done - next CMS state %d", | |
| 2512 Thread::current(), _collectorState); | |
| 2513 } | |
| 2514 } | |
| 2515 | |
| 2516 if (UseAdaptiveSizePolicy) { | |
| 2517 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 2518 size_policy()->ms_collection_end(gch->gc_cause()); | |
| 2519 } | |
| 2520 | |
| 2521 if (VerifyAfterGC && | |
| 2522 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 2523 Universe::verify(true); | |
| 2524 } | |
| 2525 if (TraceCMSState) { | |
| 2526 gclog_or_tty->print_cr("CMS Thread " INTPTR_FORMAT | |
| 2527 " exiting collection CMS state %d", | |
| 2528 Thread::current(), _collectorState); | |
| 2529 } | |
| 2530 } | |
| 2531 | |
| 2532 bool CMSCollector::waitForForegroundGC() { | |
| 2533 bool res = false; | |
| 2534 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 2535 "CMS thread should have CMS token"); | |
| 2536 // Block the foreground collector until the | |
| 2537 // background collectors decides whether to | |
| 2538 // yield. | |
| 2539 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); | |
| 2540 _foregroundGCShouldWait = true; | |
| 2541 if (_foregroundGCIsActive) { | |
| 2542 // The background collector yields to the | |
| 2543 // foreground collector and returns a value | |
| 2544 // indicating that it has yielded. The foreground | |
| 2545 // collector can proceed. | |
| 2546 res = true; | |
| 2547 _foregroundGCShouldWait = false; | |
| 2548 ConcurrentMarkSweepThread::clear_CMS_flag( | |
| 2549 ConcurrentMarkSweepThread::CMS_cms_has_token); | |
| 2550 ConcurrentMarkSweepThread::set_CMS_flag( | |
| 2551 ConcurrentMarkSweepThread::CMS_cms_wants_token); | |
| 2552 // Get a possibly blocked foreground thread going | |
| 2553 CGC_lock->notify(); | |
| 2554 if (TraceCMSState) { | |
| 2555 gclog_or_tty->print_cr("CMS Thread " INTPTR_FORMAT " waiting at CMS state %d", | |
| 2556 Thread::current(), _collectorState); | |
| 2557 } | |
| 2558 while (_foregroundGCIsActive) { | |
| 2559 CGC_lock->wait(Mutex::_no_safepoint_check_flag); | |
| 2560 } | |
| 2561 ConcurrentMarkSweepThread::set_CMS_flag( | |
| 2562 ConcurrentMarkSweepThread::CMS_cms_has_token); | |
| 2563 ConcurrentMarkSweepThread::clear_CMS_flag( | |
| 2564 ConcurrentMarkSweepThread::CMS_cms_wants_token); | |
| 2565 } | |
| 2566 if (TraceCMSState) { | |
| 2567 gclog_or_tty->print_cr("CMS Thread " INTPTR_FORMAT " continuing at CMS state %d", | |
| 2568 Thread::current(), _collectorState); | |
| 2569 } | |
| 2570 return res; | |
| 2571 } | |
| 2572 | |
| 2573 // Because of the need to lock the free lists and other structures in | |
| 2574 // the collector, common to all the generations that the collector is | |
| 2575 // collecting, we need the gc_prologues of individual CMS generations | |
| 2576 // delegate to their collector. It may have been simpler had the | |
| 2577 // current infrastructure allowed one to call a prologue on a | |
| 2578 // collector. In the absence of that we have the generation's | |
| 2579 // prologue delegate to the collector, which delegates back | |
| 2580 // some "local" work to a worker method in the individual generations | |
| 2581 // that it's responsible for collecting, while itself doing any | |
| 2582 // work common to all generations it's responsible for. A similar | |
| 2583 // comment applies to the gc_epilogue()'s. | |
| 2584 // The role of the varaible _between_prologue_and_epilogue is to | |
| 2585 // enforce the invocation protocol. | |
| 2586 void CMSCollector::gc_prologue(bool full) { | |
| 2587 // Call gc_prologue_work() for each CMSGen and PermGen that | |
| 2588 // we are responsible for. | |
| 2589 | |
| 2590 // The following locking discipline assumes that we are only called | |
| 2591 // when the world is stopped. | |
| 2592 assert(SafepointSynchronize::is_at_safepoint(), "world is stopped assumption"); | |
| 2593 | |
| 2594 // The CMSCollector prologue must call the gc_prologues for the | |
| 2595 // "generations" (including PermGen if any) that it's responsible | |
| 2596 // for. | |
| 2597 | |
| 2598 assert( Thread::current()->is_VM_thread() | |
| 2599 || ( CMSScavengeBeforeRemark | |
| 2600 && Thread::current()->is_ConcurrentGC_thread()), | |
| 2601 "Incorrect thread type for prologue execution"); | |
| 2602 | |
| 2603 if (_between_prologue_and_epilogue) { | |
| 2604 // We have already been invoked; this is a gc_prologue delegation | |
| 2605 // from yet another CMS generation that we are responsible for, just | |
| 2606 // ignore it since all relevant work has already been done. | |
| 2607 return; | |
| 2608 } | |
| 2609 | |
| 2610 // set a bit saying prologue has been called; cleared in epilogue | |
| 2611 _between_prologue_and_epilogue = true; | |
| 2612 // Claim locks for common data structures, then call gc_prologue_work() | |
| 2613 // for each CMSGen and PermGen that we are responsible for. | |
| 2614 | |
| 2615 getFreelistLocks(); // gets free list locks on constituent spaces | |
| 2616 bitMapLock()->lock_without_safepoint_check(); | |
| 2617 | |
| 2618 // Should call gc_prologue_work() for all cms gens we are responsible for | |
| 2619 bool registerClosure = _collectorState >= Marking | |
| 2620 && _collectorState < Sweeping; | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
2621 ModUnionClosure* muc = CollectedHeap::use_parallel_gc_threads() ? |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
2622 &_modUnionClosurePar |
| 0 | 2623 : &_modUnionClosure; |
| 2624 _cmsGen->gc_prologue_work(full, registerClosure, muc); | |
| 2625 _permGen->gc_prologue_work(full, registerClosure, muc); | |
| 2626 | |
| 2627 if (!full) { | |
| 2628 stats().record_gc0_begin(); | |
| 2629 } | |
| 2630 } | |
| 2631 | |
| 2632 void ConcurrentMarkSweepGeneration::gc_prologue(bool full) { | |
| 2633 // Delegate to CMScollector which knows how to coordinate between | |
| 2634 // this and any other CMS generations that it is responsible for | |
| 2635 // collecting. | |
| 2636 collector()->gc_prologue(full); | |
| 2637 } | |
| 2638 | |
| 2639 // This is a "private" interface for use by this generation's CMSCollector. | |
| 2640 // Not to be called directly by any other entity (for instance, | |
| 2641 // GenCollectedHeap, which calls the "public" gc_prologue method above). | |
| 2642 void ConcurrentMarkSweepGeneration::gc_prologue_work(bool full, | |
| 2643 bool registerClosure, ModUnionClosure* modUnionClosure) { | |
| 2644 assert(!incremental_collection_failed(), "Shouldn't be set yet"); | |
| 2645 assert(cmsSpace()->preconsumptionDirtyCardClosure() == NULL, | |
| 2646 "Should be NULL"); | |
| 2647 if (registerClosure) { | |
| 2648 cmsSpace()->setPreconsumptionDirtyCardClosure(modUnionClosure); | |
| 2649 } | |
| 2650 cmsSpace()->gc_prologue(); | |
| 2651 // Clear stat counters | |
| 2652 NOT_PRODUCT( | |
| 2653 assert(_numObjectsPromoted == 0, "check"); | |
| 2654 assert(_numWordsPromoted == 0, "check"); | |
| 2655 if (Verbose && PrintGC) { | |
| 2656 gclog_or_tty->print("Allocated "SIZE_FORMAT" objects, " | |
| 2657 SIZE_FORMAT" bytes concurrently", | |
| 2658 _numObjectsAllocated, _numWordsAllocated*sizeof(HeapWord)); | |
| 2659 } | |
| 2660 _numObjectsAllocated = 0; | |
| 2661 _numWordsAllocated = 0; | |
| 2662 ) | |
| 2663 } | |
| 2664 | |
| 2665 void CMSCollector::gc_epilogue(bool full) { | |
| 2666 // The following locking discipline assumes that we are only called | |
| 2667 // when the world is stopped. | |
| 2668 assert(SafepointSynchronize::is_at_safepoint(), | |
| 2669 "world is stopped assumption"); | |
| 2670 | |
| 2671 // Currently the CMS epilogue (see CompactibleFreeListSpace) merely checks | |
| 2672 // if linear allocation blocks need to be appropriately marked to allow the | |
| 2673 // the blocks to be parsable. We also check here whether we need to nudge the | |
| 2674 // CMS collector thread to start a new cycle (if it's not already active). | |
| 2675 assert( Thread::current()->is_VM_thread() | |
| 2676 || ( CMSScavengeBeforeRemark | |
| 2677 && Thread::current()->is_ConcurrentGC_thread()), | |
| 2678 "Incorrect thread type for epilogue execution"); | |
| 2679 | |
| 2680 if (!_between_prologue_and_epilogue) { | |
| 2681 // We have already been invoked; this is a gc_epilogue delegation | |
| 2682 // from yet another CMS generation that we are responsible for, just | |
| 2683 // ignore it since all relevant work has already been done. | |
| 2684 return; | |
| 2685 } | |
| 2686 assert(haveFreelistLocks(), "must have freelist locks"); | |
| 2687 assert_lock_strong(bitMapLock()); | |
| 2688 | |
| 2689 _cmsGen->gc_epilogue_work(full); | |
| 2690 _permGen->gc_epilogue_work(full); | |
| 2691 | |
| 2692 if (_collectorState == AbortablePreclean || _collectorState == Precleaning) { | |
| 2693 // in case sampling was not already enabled, enable it | |
| 2694 _start_sampling = true; | |
| 2695 } | |
| 2696 // reset _eden_chunk_array so sampling starts afresh | |
| 2697 _eden_chunk_index = 0; | |
| 2698 | |
| 2699 size_t cms_used = _cmsGen->cmsSpace()->used(); | |
| 2700 size_t perm_used = _permGen->cmsSpace()->used(); | |
| 2701 | |
| 2702 // update performance counters - this uses a special version of | |
| 2703 // update_counters() that allows the utilization to be passed as a | |
| 2704 // parameter, avoiding multiple calls to used(). | |
| 2705 // | |
| 2706 _cmsGen->update_counters(cms_used); | |
| 2707 _permGen->update_counters(perm_used); | |
| 2708 | |
| 2709 if (CMSIncrementalMode) { | |
| 2710 icms_update_allocation_limits(); | |
| 2711 } | |
| 2712 | |
| 2713 bitMapLock()->unlock(); | |
| 2714 releaseFreelistLocks(); | |
| 2715 | |
|
3799
48048b59a551
7061204: clean the chunk table synchronously in embedded builds
jcoomes
parents:
3746
diff
changeset
|
2716 if (!CleanChunkPoolAsync) { |
|
48048b59a551
7061204: clean the chunk table synchronously in embedded builds
jcoomes
parents:
3746
diff
changeset
|
2717 Chunk::clean_chunk_pool(); |
|
48048b59a551
7061204: clean the chunk table synchronously in embedded builds
jcoomes
parents:
3746
diff
changeset
|
2718 } |
|
48048b59a551
7061204: clean the chunk table synchronously in embedded builds
jcoomes
parents:
3746
diff
changeset
|
2719 |
| 0 | 2720 _between_prologue_and_epilogue = false; // ready for next cycle |
| 2721 } | |
| 2722 | |
| 2723 void ConcurrentMarkSweepGeneration::gc_epilogue(bool full) { | |
| 2724 collector()->gc_epilogue(full); | |
| 2725 | |
| 2726 // Also reset promotion tracking in par gc thread states. | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
2727 if (CollectedHeap::use_parallel_gc_threads()) { |
| 0 | 2728 for (uint i = 0; i < ParallelGCThreads; i++) { |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2729 _par_gc_thread_states[i]->promo.stopTrackingPromotions(i); |
| 0 | 2730 } |
| 2731 } | |
| 2732 } | |
| 2733 | |
| 2734 void ConcurrentMarkSweepGeneration::gc_epilogue_work(bool full) { | |
| 2735 assert(!incremental_collection_failed(), "Should have been cleared"); | |
| 2736 cmsSpace()->setPreconsumptionDirtyCardClosure(NULL); | |
| 2737 cmsSpace()->gc_epilogue(); | |
| 2738 // Print stat counters | |
| 2739 NOT_PRODUCT( | |
| 2740 assert(_numObjectsAllocated == 0, "check"); | |
| 2741 assert(_numWordsAllocated == 0, "check"); | |
| 2742 if (Verbose && PrintGC) { | |
| 2743 gclog_or_tty->print("Promoted "SIZE_FORMAT" objects, " | |
| 2744 SIZE_FORMAT" bytes", | |
| 2745 _numObjectsPromoted, _numWordsPromoted*sizeof(HeapWord)); | |
| 2746 } | |
| 2747 _numObjectsPromoted = 0; | |
| 2748 _numWordsPromoted = 0; | |
| 2749 ) | |
| 2750 | |
| 2751 if (PrintGC && Verbose) { | |
| 2752 // Call down the chain in contiguous_available needs the freelistLock | |
| 2753 // so print this out before releasing the freeListLock. | |
| 2754 gclog_or_tty->print(" Contiguous available "SIZE_FORMAT" bytes ", | |
| 2755 contiguous_available()); | |
| 2756 } | |
| 2757 } | |
| 2758 | |
| 2759 #ifndef PRODUCT | |
| 2760 bool CMSCollector::have_cms_token() { | |
| 2761 Thread* thr = Thread::current(); | |
| 2762 if (thr->is_VM_thread()) { | |
| 2763 return ConcurrentMarkSweepThread::vm_thread_has_cms_token(); | |
| 2764 } else if (thr->is_ConcurrentGC_thread()) { | |
| 2765 return ConcurrentMarkSweepThread::cms_thread_has_cms_token(); | |
| 2766 } else if (thr->is_GC_task_thread()) { | |
| 2767 return ConcurrentMarkSweepThread::vm_thread_has_cms_token() && | |
| 2768 ParGCRareEvent_lock->owned_by_self(); | |
| 2769 } | |
| 2770 return false; | |
| 2771 } | |
| 2772 #endif | |
| 2773 | |
| 2774 // Check reachability of the given heap address in CMS generation, | |
| 2775 // treating all other generations as roots. | |
| 2776 bool CMSCollector::is_cms_reachable(HeapWord* addr) { | |
| 2777 // We could "guarantee" below, rather than assert, but i'll | |
| 2778 // leave these as "asserts" so that an adventurous debugger | |
| 2779 // could try this in the product build provided some subset of | |
| 2780 // the conditions were met, provided they were intersted in the | |
| 2781 // results and knew that the computation below wouldn't interfere | |
| 2782 // with other concurrent computations mutating the structures | |
| 2783 // being read or written. | |
| 2784 assert(SafepointSynchronize::is_at_safepoint(), | |
| 2785 "Else mutations in object graph will make answer suspect"); | |
| 2786 assert(have_cms_token(), "Should hold cms token"); | |
| 2787 assert(haveFreelistLocks(), "must hold free list locks"); | |
| 2788 assert_lock_strong(bitMapLock()); | |
| 2789 | |
| 2790 // Clear the marking bit map array before starting, but, just | |
| 2791 // for kicks, first report if the given address is already marked | |
| 2792 gclog_or_tty->print_cr("Start: Address 0x%x is%s marked", addr, | |
| 2793 _markBitMap.isMarked(addr) ? "" : " not"); | |
| 2794 | |
| 2795 if (verify_after_remark()) { | |
| 2796 MutexLockerEx x(verification_mark_bm()->lock(), Mutex::_no_safepoint_check_flag); | |
| 2797 bool result = verification_mark_bm()->isMarked(addr); | |
| 2798 gclog_or_tty->print_cr("TransitiveMark: Address 0x%x %s marked", addr, | |
| 2799 result ? "IS" : "is NOT"); | |
| 2800 return result; | |
| 2801 } else { | |
| 2802 gclog_or_tty->print_cr("Could not compute result"); | |
| 2803 return false; | |
| 2804 } | |
| 2805 } | |
| 2806 | |
| 2807 //////////////////////////////////////////////////////// | |
| 2808 // CMS Verification Support | |
| 2809 //////////////////////////////////////////////////////// | |
| 2810 // Following the remark phase, the following invariant | |
| 2811 // should hold -- each object in the CMS heap which is | |
| 2812 // marked in markBitMap() should be marked in the verification_mark_bm(). | |
| 2813 | |
| 2814 class VerifyMarkedClosure: public BitMapClosure { | |
| 2815 CMSBitMap* _marks; | |
| 2816 bool _failed; | |
| 2817 | |
| 2818 public: | |
| 2819 VerifyMarkedClosure(CMSBitMap* bm): _marks(bm), _failed(false) {} | |
| 2820 | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
2821 bool do_bit(size_t offset) { |
| 0 | 2822 HeapWord* addr = _marks->offsetToHeapWord(offset); |
| 2823 if (!_marks->isMarked(addr)) { | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2824 oop(addr)->print_on(gclog_or_tty); |
| 0 | 2825 gclog_or_tty->print_cr(" ("INTPTR_FORMAT" should have been marked)", addr); |
| 2826 _failed = true; | |
| 2827 } | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
2828 return true; |
| 0 | 2829 } |
| 2830 | |
| 2831 bool failed() { return _failed; } | |
| 2832 }; | |
| 2833 | |
| 2834 bool CMSCollector::verify_after_remark() { | |
| 2835 gclog_or_tty->print(" [Verifying CMS Marking... "); | |
| 2836 MutexLockerEx ml(verification_mark_bm()->lock(), Mutex::_no_safepoint_check_flag); | |
| 2837 static bool init = false; | |
| 2838 | |
| 2839 assert(SafepointSynchronize::is_at_safepoint(), | |
| 2840 "Else mutations in object graph will make answer suspect"); | |
| 2841 assert(have_cms_token(), | |
| 2842 "Else there may be mutual interference in use of " | |
| 2843 " verification data structures"); | |
| 2844 assert(_collectorState > Marking && _collectorState <= Sweeping, | |
| 2845 "Else marking info checked here may be obsolete"); | |
| 2846 assert(haveFreelistLocks(), "must hold free list locks"); | |
| 2847 assert_lock_strong(bitMapLock()); | |
| 2848 | |
| 2849 | |
| 2850 // Allocate marking bit map if not already allocated | |
| 2851 if (!init) { // first time | |
| 2852 if (!verification_mark_bm()->allocate(_span)) { | |
| 2853 return false; | |
| 2854 } | |
| 2855 init = true; | |
| 2856 } | |
| 2857 | |
| 2858 assert(verification_mark_stack()->isEmpty(), "Should be empty"); | |
| 2859 | |
| 2860 // Turn off refs discovery -- so we will be tracing through refs. | |
| 2861 // This is as intended, because by this time | |
| 2862 // GC must already have cleared any refs that need to be cleared, | |
| 2863 // and traced those that need to be marked; moreover, | |
| 2864 // the marking done here is not going to intefere in any | |
| 2865 // way with the marking information used by GC. | |
| 2866 NoRefDiscovery no_discovery(ref_processor()); | |
| 2867 | |
| 2868 COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact;) | |
| 2869 | |
| 2870 // Clear any marks from a previous round | |
| 2871 verification_mark_bm()->clear_all(); | |
| 2872 assert(verification_mark_stack()->isEmpty(), "markStack should be empty"); | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2873 verify_work_stacks_empty(); |
| 0 | 2874 |
| 2875 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 2876 gch->ensure_parsability(false); // fill TLABs, but no need to retire them | |
| 2877 // Update the saved marks which may affect the root scans. | |
| 2878 gch->save_marks(); | |
| 2879 | |
| 2880 if (CMSRemarkVerifyVariant == 1) { | |
| 2881 // In this first variant of verification, we complete | |
| 2882 // all marking, then check if the new marks-verctor is | |
| 2883 // a subset of the CMS marks-vector. | |
| 2884 verify_after_remark_work_1(); | |
| 2885 } else if (CMSRemarkVerifyVariant == 2) { | |
| 2886 // In this second variant of verification, we flag an error | |
| 2887 // (i.e. an object reachable in the new marks-vector not reachable | |
| 2888 // in the CMS marks-vector) immediately, also indicating the | |
| 2889 // identify of an object (A) that references the unmarked object (B) -- | |
| 2890 // presumably, a mutation to A failed to be picked up by preclean/remark? | |
| 2891 verify_after_remark_work_2(); | |
| 2892 } else { | |
| 2893 warning("Unrecognized value %d for CMSRemarkVerifyVariant", | |
| 2894 CMSRemarkVerifyVariant); | |
| 2895 } | |
| 2896 gclog_or_tty->print(" done] "); | |
| 2897 return true; | |
| 2898 } | |
| 2899 | |
| 2900 void CMSCollector::verify_after_remark_work_1() { | |
| 2901 ResourceMark rm; | |
| 2902 HandleMark hm; | |
| 2903 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 2904 | |
| 2905 // Mark from roots one level into CMS | |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
2906 MarkRefsIntoClosure notOlder(_span, verification_mark_bm()); |
| 0 | 2907 gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel. |
| 2908 | |
| 2909 gch->gen_process_strong_roots(_cmsGen->level(), | |
| 2910 true, // younger gens are roots | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2911 true, // activate StrongRootsScope |
| 0 | 2912 true, // collecting perm gen |
| 2913 SharedHeap::ScanningOption(roots_scanning_options()), | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2914 ¬Older, |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2915 true, // walk code active on stacks |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2916 NULL); |
| 0 | 2917 |
| 2918 // Now mark from the roots | |
| 2919 assert(_revisitStack.isEmpty(), "Should be empty"); | |
| 2920 MarkFromRootsClosure markFromRootsClosure(this, _span, | |
| 2921 verification_mark_bm(), verification_mark_stack(), &_revisitStack, | |
| 2922 false /* don't yield */, true /* verifying */); | |
| 2923 assert(_restart_addr == NULL, "Expected pre-condition"); | |
| 2924 verification_mark_bm()->iterate(&markFromRootsClosure); | |
| 2925 while (_restart_addr != NULL) { | |
| 2926 // Deal with stack overflow: by restarting at the indicated | |
| 2927 // address. | |
| 2928 HeapWord* ra = _restart_addr; | |
| 2929 markFromRootsClosure.reset(ra); | |
| 2930 _restart_addr = NULL; | |
| 2931 verification_mark_bm()->iterate(&markFromRootsClosure, ra, _span.end()); | |
| 2932 } | |
| 2933 assert(verification_mark_stack()->isEmpty(), "Should have been drained"); | |
| 2934 verify_work_stacks_empty(); | |
| 2935 // Should reset the revisit stack above, since no class tree | |
| 2936 // surgery is forthcoming. | |
| 2937 _revisitStack.reset(); // throwing away all contents | |
| 2938 | |
| 2939 // Marking completed -- now verify that each bit marked in | |
| 2940 // verification_mark_bm() is also marked in markBitMap(); flag all | |
| 2941 // errors by printing corresponding objects. | |
| 2942 VerifyMarkedClosure vcl(markBitMap()); | |
| 2943 verification_mark_bm()->iterate(&vcl); | |
| 2944 if (vcl.failed()) { | |
| 2945 gclog_or_tty->print("Verification failed"); | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2946 Universe::heap()->print_on(gclog_or_tty); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
2947 fatal("CMS: failed marking verification after remark"); |
| 0 | 2948 } |
| 2949 } | |
| 2950 | |
| 2951 void CMSCollector::verify_after_remark_work_2() { | |
| 2952 ResourceMark rm; | |
| 2953 HandleMark hm; | |
| 2954 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 2955 | |
| 2956 // Mark from roots one level into CMS | |
| 2957 MarkRefsIntoVerifyClosure notOlder(_span, verification_mark_bm(), | |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
2958 markBitMap()); |
| 0 | 2959 gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel. |
| 2960 gch->gen_process_strong_roots(_cmsGen->level(), | |
| 2961 true, // younger gens are roots | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2962 true, // activate StrongRootsScope |
| 0 | 2963 true, // collecting perm gen |
| 2964 SharedHeap::ScanningOption(roots_scanning_options()), | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2965 ¬Older, |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2966 true, // walk code active on stacks |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
2967 NULL); |
| 0 | 2968 |
| 2969 // Now mark from the roots | |
| 2970 assert(_revisitStack.isEmpty(), "Should be empty"); | |
| 2971 MarkFromRootsVerifyClosure markFromRootsClosure(this, _span, | |
| 2972 verification_mark_bm(), markBitMap(), verification_mark_stack()); | |
| 2973 assert(_restart_addr == NULL, "Expected pre-condition"); | |
| 2974 verification_mark_bm()->iterate(&markFromRootsClosure); | |
| 2975 while (_restart_addr != NULL) { | |
| 2976 // Deal with stack overflow: by restarting at the indicated | |
| 2977 // address. | |
| 2978 HeapWord* ra = _restart_addr; | |
| 2979 markFromRootsClosure.reset(ra); | |
| 2980 _restart_addr = NULL; | |
| 2981 verification_mark_bm()->iterate(&markFromRootsClosure, ra, _span.end()); | |
| 2982 } | |
| 2983 assert(verification_mark_stack()->isEmpty(), "Should have been drained"); | |
| 2984 verify_work_stacks_empty(); | |
| 2985 // Should reset the revisit stack above, since no class tree | |
| 2986 // surgery is forthcoming. | |
| 2987 _revisitStack.reset(); // throwing away all contents | |
| 2988 | |
| 2989 // Marking completed -- now verify that each bit marked in | |
| 2990 // verification_mark_bm() is also marked in markBitMap(); flag all | |
| 2991 // errors by printing corresponding objects. | |
| 2992 VerifyMarkedClosure vcl(markBitMap()); | |
| 2993 verification_mark_bm()->iterate(&vcl); | |
| 2994 assert(!vcl.failed(), "Else verification above should not have succeeded"); | |
| 2995 } | |
| 2996 | |
| 2997 void ConcurrentMarkSweepGeneration::save_marks() { | |
| 2998 // delegate to CMS space | |
| 2999 cmsSpace()->save_marks(); | |
| 3000 for (uint i = 0; i < ParallelGCThreads; i++) { | |
| 3001 _par_gc_thread_states[i]->promo.startTrackingPromotions(); | |
| 3002 } | |
| 3003 } | |
| 3004 | |
| 3005 bool ConcurrentMarkSweepGeneration::no_allocs_since_save_marks() { | |
| 3006 return cmsSpace()->no_allocs_since_save_marks(); | |
| 3007 } | |
| 3008 | |
| 3009 #define CMS_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ | |
| 3010 \ | |
| 3011 void ConcurrentMarkSweepGeneration:: \ | |
| 3012 oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ | |
| 3013 cl->set_generation(this); \ | |
| 3014 cmsSpace()->oop_since_save_marks_iterate##nv_suffix(cl); \ | |
| 3015 cl->reset_generation(); \ | |
| 3016 save_marks(); \ | |
| 3017 } | |
| 3018 | |
| 3019 ALL_SINCE_SAVE_MARKS_CLOSURES(CMS_SINCE_SAVE_MARKS_DEFN) | |
| 3020 | |
| 3021 void | |
| 3022 ConcurrentMarkSweepGeneration::object_iterate_since_last_GC(ObjectClosure* blk) | |
| 3023 { | |
| 3024 // Not currently implemented; need to do the following. -- ysr. | |
| 3025 // dld -- I think that is used for some sort of allocation profiler. So it | |
| 3026 // really means the objects allocated by the mutator since the last | |
| 3027 // GC. We could potentially implement this cheaply by recording only | |
| 3028 // the direct allocations in a side data structure. | |
| 3029 // | |
| 3030 // I think we probably ought not to be required to support these | |
| 3031 // iterations at any arbitrary point; I think there ought to be some | |
| 3032 // call to enable/disable allocation profiling in a generation/space, | |
| 3033 // and the iterator ought to return the objects allocated in the | |
| 3034 // gen/space since the enable call, or the last iterator call (which | |
| 3035 // will probably be at a GC.) That way, for gens like CM&S that would | |
| 3036 // require some extra data structure to support this, we only pay the | |
| 3037 // cost when it's in use... | |
| 3038 cmsSpace()->object_iterate_since_last_GC(blk); | |
| 3039 } | |
| 3040 | |
| 3041 void | |
| 3042 ConcurrentMarkSweepGeneration::younger_refs_iterate(OopsInGenClosure* cl) { | |
| 3043 cl->set_generation(this); | |
| 3044 younger_refs_in_space_iterate(_cmsSpace, cl); | |
| 3045 cl->reset_generation(); | |
| 3046 } | |
| 3047 | |
| 3048 void | |
| 3049 ConcurrentMarkSweepGeneration::oop_iterate(MemRegion mr, OopClosure* cl) { | |
| 3050 if (freelistLock()->owned_by_self()) { | |
| 3051 Generation::oop_iterate(mr, cl); | |
| 3052 } else { | |
| 3053 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 3054 Generation::oop_iterate(mr, cl); | |
| 3055 } | |
| 3056 } | |
| 3057 | |
| 3058 void | |
| 3059 ConcurrentMarkSweepGeneration::oop_iterate(OopClosure* cl) { | |
| 3060 if (freelistLock()->owned_by_self()) { | |
| 3061 Generation::oop_iterate(cl); | |
| 3062 } else { | |
| 3063 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 3064 Generation::oop_iterate(cl); | |
| 3065 } | |
| 3066 } | |
| 3067 | |
| 3068 void | |
| 3069 ConcurrentMarkSweepGeneration::object_iterate(ObjectClosure* cl) { | |
| 3070 if (freelistLock()->owned_by_self()) { | |
| 3071 Generation::object_iterate(cl); | |
| 3072 } else { | |
| 3073 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 3074 Generation::object_iterate(cl); | |
| 3075 } | |
| 3076 } | |
| 3077 | |
| 3078 void | |
|
517
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3079 ConcurrentMarkSweepGeneration::safe_object_iterate(ObjectClosure* cl) { |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3080 if (freelistLock()->owned_by_self()) { |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3081 Generation::safe_object_iterate(cl); |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3082 } else { |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3083 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3084 Generation::safe_object_iterate(cl); |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3085 } |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3086 } |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3087 |
|
e9be0e04635a
6689653: JMapPerm fails with UseConcMarkSweepIncGC and compressed oops off
jmasa
parents:
457
diff
changeset
|
3088 void |
| 0 | 3089 ConcurrentMarkSweepGeneration::pre_adjust_pointers() { |
| 3090 } | |
| 3091 | |
| 3092 void | |
| 3093 ConcurrentMarkSweepGeneration::post_compact() { | |
| 3094 } | |
| 3095 | |
| 3096 void | |
| 3097 ConcurrentMarkSweepGeneration::prepare_for_verify() { | |
| 3098 // Fix the linear allocation blocks to look like free blocks. | |
| 3099 | |
| 3100 // Locks are normally acquired/released in gc_prologue/gc_epilogue, but those | |
| 3101 // are not called when the heap is verified during universe initialization and | |
| 3102 // at vm shutdown. | |
| 3103 if (freelistLock()->owned_by_self()) { | |
| 3104 cmsSpace()->prepare_for_verify(); | |
| 3105 } else { | |
| 3106 MutexLockerEx fll(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 3107 cmsSpace()->prepare_for_verify(); | |
| 3108 } | |
| 3109 } | |
| 3110 | |
| 3111 void | |
| 6008 | 3112 ConcurrentMarkSweepGeneration::verify() { |
| 0 | 3113 // Locks are normally acquired/released in gc_prologue/gc_epilogue, but those |
| 3114 // are not called when the heap is verified during universe initialization and | |
| 3115 // at vm shutdown. | |
| 3116 if (freelistLock()->owned_by_self()) { | |
| 6008 | 3117 cmsSpace()->verify(); |
| 0 | 3118 } else { |
| 3119 MutexLockerEx fll(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 6008 | 3120 cmsSpace()->verify(); |
| 3121 } | |
| 3122 } | |
| 3123 | |
| 3124 void CMSCollector::verify() { | |
| 3125 _cmsGen->verify(); | |
| 3126 _permGen->verify(); | |
| 0 | 3127 } |
| 3128 | |
| 3129 #ifndef PRODUCT | |
| 3130 bool CMSCollector::overflow_list_is_empty() const { | |
| 3131 assert(_num_par_pushes >= 0, "Inconsistency"); | |
| 3132 if (_overflow_list == NULL) { | |
| 3133 assert(_num_par_pushes == 0, "Inconsistency"); | |
| 3134 } | |
| 3135 return _overflow_list == NULL; | |
| 3136 } | |
| 3137 | |
| 3138 // The methods verify_work_stacks_empty() and verify_overflow_empty() | |
| 3139 // merely consolidate assertion checks that appear to occur together frequently. | |
| 3140 void CMSCollector::verify_work_stacks_empty() const { | |
| 3141 assert(_markStack.isEmpty(), "Marking stack should be empty"); | |
| 3142 assert(overflow_list_is_empty(), "Overflow list should be empty"); | |
| 3143 } | |
| 3144 | |
| 3145 void CMSCollector::verify_overflow_empty() const { | |
| 3146 assert(overflow_list_is_empty(), "Overflow list should be empty"); | |
| 3147 assert(no_preserved_marks(), "No preserved marks"); | |
| 3148 } | |
| 3149 #endif // PRODUCT | |
| 3150 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3151 // Decide if we want to enable class unloading as part of the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3152 // ensuing concurrent GC cycle. We will collect the perm gen and |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3153 // unload classes if it's the case that: |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3154 // (1) an explicit gc request has been made and the flag |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3155 // ExplicitGCInvokesConcurrentAndUnloadsClasses is set, OR |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3156 // (2) (a) class unloading is enabled at the command line, and |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3157 // (b) (i) perm gen threshold has been crossed, or |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3158 // (ii) old gen is getting really full, or |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3159 // (iii) the previous N CMS collections did not collect the |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3160 // perm gen |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3161 // NOTE: Provided there is no change in the state of the heap between |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3162 // calls to this method, it should have idempotent results. Moreover, |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3163 // its results should be monotonically increasing (i.e. going from 0 to 1, |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3164 // but not 1 to 0) between successive calls between which the heap was |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3165 // not collected. For the implementation below, it must thus rely on |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3166 // the property that concurrent_cycles_since_last_unload() |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3167 // will not decrease unless a collection cycle happened and that |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3168 // _permGen->should_concurrent_collect() and _cmsGen->is_too_full() are |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3169 // themselves also monotonic in that sense. See check_monotonicity() |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3170 // below. |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3171 bool CMSCollector::update_should_unload_classes() { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3172 _should_unload_classes = false; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3173 // Condition 1 above |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3174 if (_full_gc_requested && ExplicitGCInvokesConcurrentAndUnloadsClasses) { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3175 _should_unload_classes = true; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3176 } else if (CMSClassUnloadingEnabled) { // Condition 2.a above |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3177 // Disjuncts 2.b.(i,ii,iii) above |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3178 _should_unload_classes = (concurrent_cycles_since_last_unload() >= |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3179 CMSClassUnloadingMaxInterval) |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3180 || _permGen->should_concurrent_collect() |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3181 || _cmsGen->is_too_full(); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3182 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3183 return _should_unload_classes; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3184 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3185 |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3186 bool ConcurrentMarkSweepGeneration::is_too_full() const { |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3187 bool res = should_concurrent_collect(); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3188 res = res && (occupancy() > (double)CMSIsTooFullPercentage/100.0); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3189 return res; |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3190 } |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3191 |
| 0 | 3192 void CMSCollector::setup_cms_unloading_and_verification_state() { |
|
3293
1f4413413144
7039089: G1: changeset for 7037276 broke heap verification, and related cleanups
ysr
parents:
2379
diff
changeset
|
3193 const bool should_verify = VerifyBeforeGC || VerifyAfterGC || VerifyDuringGC |
| 0 | 3194 || VerifyBeforeExit; |
|
3293
1f4413413144
7039089: G1: changeset for 7037276 broke heap verification, and related cleanups
ysr
parents:
2379
diff
changeset
|
3195 const int rso = SharedHeap::SO_Strings | SharedHeap::SO_CodeCache; |
| 0 | 3196 |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3197 if (should_unload_classes()) { // Should unload classes this cycle |
| 0 | 3198 remove_root_scanning_option(rso); // Shrink the root set appropriately |
| 3199 set_verifying(should_verify); // Set verification state for this cycle | |
| 3200 return; // Nothing else needs to be done at this time | |
| 3201 } | |
| 3202 | |
| 3203 // Not unloading classes this cycle | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3204 assert(!should_unload_classes(), "Inconsitency!"); |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
3205 if ((!verifying() || unloaded_classes_last_cycle()) && should_verify) { |
| 0 | 3206 // We were not verifying, or we _were_ unloading classes in the last cycle, |
| 3207 // AND some verification options are enabled this cycle; in this case, | |
| 3208 // we must make sure that the deadness map is allocated if not already so, | |
| 3209 // and cleared (if already allocated previously -- | |
| 3210 // CMSBitMap::sizeInBits() is used to determine if it's allocated). | |
| 3211 if (perm_gen_verify_bit_map()->sizeInBits() == 0) { | |
| 3212 if (!perm_gen_verify_bit_map()->allocate(_permGen->reserved())) { | |
| 3213 warning("Failed to allocate permanent generation verification CMS Bit Map;\n" | |
| 3214 "permanent generation verification disabled"); | |
| 3215 return; // Note that we leave verification disabled, so we'll retry this | |
| 3216 // allocation next cycle. We _could_ remember this failure | |
| 3217 // and skip further attempts and permanently disable verification | |
| 3218 // attempts if that is considered more desirable. | |
| 3219 } | |
| 3220 assert(perm_gen_verify_bit_map()->covers(_permGen->reserved()), | |
| 3221 "_perm_gen_ver_bit_map inconsistency?"); | |
| 3222 } else { | |
| 3223 perm_gen_verify_bit_map()->clear_all(); | |
| 3224 } | |
| 3225 // Include symbols, strings and code cache elements to prevent their resurrection. | |
| 3226 add_root_scanning_option(rso); | |
| 3227 set_verifying(true); | |
| 3228 } else if (verifying() && !should_verify) { | |
| 3229 // We were verifying, but some verification flags got disabled. | |
| 3230 set_verifying(false); | |
| 3231 // Exclude symbols, strings and code cache elements from root scanning to | |
| 3232 // reduce IM and RM pauses. | |
| 3233 remove_root_scanning_option(rso); | |
| 3234 } | |
| 3235 } | |
| 3236 | |
| 3237 | |
| 3238 #ifndef PRODUCT | |
| 3239 HeapWord* CMSCollector::block_start(const void* p) const { | |
| 3240 const HeapWord* addr = (HeapWord*)p; | |
| 3241 if (_span.contains(p)) { | |
| 3242 if (_cmsGen->cmsSpace()->is_in_reserved(addr)) { | |
| 3243 return _cmsGen->cmsSpace()->block_start(p); | |
| 3244 } else { | |
| 3245 assert(_permGen->cmsSpace()->is_in_reserved(addr), | |
| 3246 "Inconsistent _span?"); | |
| 3247 return _permGen->cmsSpace()->block_start(p); | |
| 3248 } | |
| 3249 } | |
| 3250 return NULL; | |
| 3251 } | |
| 3252 #endif | |
| 3253 | |
| 3254 HeapWord* | |
| 3255 ConcurrentMarkSweepGeneration::expand_and_allocate(size_t word_size, | |
| 3256 bool tlab, | |
| 3257 bool parallel) { | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3258 CMSSynchronousYieldRequest yr; |
| 0 | 3259 assert(!tlab, "Can't deal with TLAB allocation"); |
| 3260 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 3261 expand(word_size*HeapWordSize, MinHeapDeltaBytes, | |
| 3262 CMSExpansionCause::_satisfy_allocation); | |
| 3263 if (GCExpandToAllocateDelayMillis > 0) { | |
| 3264 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); | |
| 3265 } | |
|
9
173195ff483a
6642634: Test nsk/regression/b6186200 crashed with SIGSEGV
ysr
parents:
7
diff
changeset
|
3266 return have_lock_and_allocate(word_size, tlab); |
| 0 | 3267 } |
| 3268 | |
| 3269 // YSR: All of this generation expansion/shrinking stuff is an exact copy of | |
| 3270 // OneContigSpaceCardGeneration, which makes me wonder if we should move this | |
| 3271 // to CardGeneration and share it... | |
|
271
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3272 bool ConcurrentMarkSweepGeneration::expand(size_t bytes, size_t expand_bytes) { |
|
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3273 return CardGeneration::expand(bytes, expand_bytes); |
|
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3274 } |
|
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3275 |
| 0 | 3276 void ConcurrentMarkSweepGeneration::expand(size_t bytes, size_t expand_bytes, |
| 3277 CMSExpansionCause::Cause cause) | |
| 3278 { | |
|
271
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3279 |
|
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3280 bool success = expand(bytes, expand_bytes); |
|
818a18cd69a8
6730514: assertion failure in mangling code when expanding by 0 bytes
jmasa
parents:
196
diff
changeset
|
3281 |
| 0 | 3282 // remember why we expanded; this information is used |
| 3283 // by shouldConcurrentCollect() when making decisions on whether to start | |
| 3284 // a new CMS cycle. | |
| 3285 if (success) { | |
| 3286 set_expansion_cause(cause); | |
| 3287 if (PrintGCDetails && Verbose) { | |
| 3288 gclog_or_tty->print_cr("Expanded CMS gen for %s", | |
| 3289 CMSExpansionCause::to_string(cause)); | |
| 3290 } | |
| 3291 } | |
| 3292 } | |
| 3293 | |
| 3294 HeapWord* ConcurrentMarkSweepGeneration::expand_and_par_lab_allocate(CMSParGCThreadState* ps, size_t word_sz) { | |
| 3295 HeapWord* res = NULL; | |
| 3296 MutexLocker x(ParGCRareEvent_lock); | |
| 3297 while (true) { | |
| 3298 // Expansion by some other thread might make alloc OK now: | |
| 3299 res = ps->lab.alloc(word_sz); | |
| 3300 if (res != NULL) return res; | |
| 3301 // If there's not enough expansion space available, give up. | |
| 3302 if (_virtual_space.uncommitted_size() < (word_sz * HeapWordSize)) { | |
| 3303 return NULL; | |
| 3304 } | |
| 3305 // Otherwise, we try expansion. | |
| 3306 expand(word_sz*HeapWordSize, MinHeapDeltaBytes, | |
| 3307 CMSExpansionCause::_allocate_par_lab); | |
| 3308 // Now go around the loop and try alloc again; | |
| 3309 // A competing par_promote might beat us to the expansion space, | |
| 3310 // so we may go around the loop again if promotion fails agaion. | |
| 3311 if (GCExpandToAllocateDelayMillis > 0) { | |
| 3312 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); | |
| 3313 } | |
| 3314 } | |
| 3315 } | |
| 3316 | |
| 3317 | |
| 3318 bool ConcurrentMarkSweepGeneration::expand_and_ensure_spooling_space( | |
| 3319 PromotionInfo* promo) { | |
| 3320 MutexLocker x(ParGCRareEvent_lock); | |
| 3321 size_t refill_size_bytes = promo->refillSize() * HeapWordSize; | |
| 3322 while (true) { | |
| 3323 // Expansion by some other thread might make alloc OK now: | |
| 3324 if (promo->ensure_spooling_space()) { | |
| 3325 assert(promo->has_spooling_space(), | |
| 3326 "Post-condition of successful ensure_spooling_space()"); | |
| 3327 return true; | |
| 3328 } | |
| 3329 // If there's not enough expansion space available, give up. | |
| 3330 if (_virtual_space.uncommitted_size() < refill_size_bytes) { | |
| 3331 return false; | |
| 3332 } | |
| 3333 // Otherwise, we try expansion. | |
| 3334 expand(refill_size_bytes, MinHeapDeltaBytes, | |
| 3335 CMSExpansionCause::_allocate_par_spooling_space); | |
| 3336 // Now go around the loop and try alloc again; | |
| 3337 // A competing allocation might beat us to the expansion space, | |
| 3338 // so we may go around the loop again if allocation fails again. | |
| 3339 if (GCExpandToAllocateDelayMillis > 0) { | |
| 3340 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); | |
| 3341 } | |
| 3342 } | |
| 3343 } | |
| 3344 | |
| 3345 | |
| 3346 | |
| 3347 void ConcurrentMarkSweepGeneration::shrink(size_t bytes) { | |
| 3348 assert_locked_or_safepoint(Heap_lock); | |
| 3349 size_t size = ReservedSpace::page_align_size_down(bytes); | |
| 3350 if (size > 0) { | |
| 3351 shrink_by(size); | |
| 3352 } | |
| 3353 } | |
| 3354 | |
| 3355 bool ConcurrentMarkSweepGeneration::grow_by(size_t bytes) { | |
| 3356 assert_locked_or_safepoint(Heap_lock); | |
| 3357 bool result = _virtual_space.expand_by(bytes); | |
| 3358 if (result) { | |
| 3359 HeapWord* old_end = _cmsSpace->end(); | |
| 3360 size_t new_word_size = | |
| 3361 heap_word_size(_virtual_space.committed_size()); | |
| 3362 MemRegion mr(_cmsSpace->bottom(), new_word_size); | |
| 3363 _bts->resize(new_word_size); // resize the block offset shared array | |
| 3364 Universe::heap()->barrier_set()->resize_covered_region(mr); | |
| 3365 // Hmmmm... why doesn't CFLS::set_end verify locking? | |
| 3366 // This is quite ugly; FIX ME XXX | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
3367 _cmsSpace->assert_locked(freelistLock()); |
| 0 | 3368 _cmsSpace->set_end((HeapWord*)_virtual_space.high()); |
| 3369 | |
| 3370 // update the space and generation capacity counters | |
| 3371 if (UsePerfData) { | |
| 3372 _space_counters->update_capacity(); | |
| 3373 _gen_counters->update_all(); | |
| 3374 } | |
| 3375 | |
| 3376 if (Verbose && PrintGC) { | |
| 3377 size_t new_mem_size = _virtual_space.committed_size(); | |
| 3378 size_t old_mem_size = new_mem_size - bytes; | |
| 3379 gclog_or_tty->print_cr("Expanding %s from %ldK by %ldK to %ldK", | |
| 3380 name(), old_mem_size/K, bytes/K, new_mem_size/K); | |
| 3381 } | |
| 3382 } | |
| 3383 return result; | |
| 3384 } | |
| 3385 | |
| 3386 bool ConcurrentMarkSweepGeneration::grow_to_reserved() { | |
| 3387 assert_locked_or_safepoint(Heap_lock); | |
| 3388 bool success = true; | |
| 3389 const size_t remaining_bytes = _virtual_space.uncommitted_size(); | |
| 3390 if (remaining_bytes > 0) { | |
| 3391 success = grow_by(remaining_bytes); | |
| 3392 DEBUG_ONLY(if (!success) warning("grow to reserved failed");) | |
| 3393 } | |
| 3394 return success; | |
| 3395 } | |
| 3396 | |
| 3397 void ConcurrentMarkSweepGeneration::shrink_by(size_t bytes) { | |
| 3398 assert_locked_or_safepoint(Heap_lock); | |
| 3399 assert_lock_strong(freelistLock()); | |
| 3400 // XXX Fix when compaction is implemented. | |
| 3401 warning("Shrinking of CMS not yet implemented"); | |
| 3402 return; | |
| 3403 } | |
| 3404 | |
| 3405 | |
| 3406 // Simple ctor/dtor wrapper for accounting & timer chores around concurrent | |
| 3407 // phases. | |
| 3408 class CMSPhaseAccounting: public StackObj { | |
| 3409 public: | |
| 3410 CMSPhaseAccounting(CMSCollector *collector, | |
| 3411 const char *phase, | |
| 3412 bool print_cr = true); | |
| 3413 ~CMSPhaseAccounting(); | |
| 3414 | |
| 3415 private: | |
| 3416 CMSCollector *_collector; | |
| 3417 const char *_phase; | |
| 3418 elapsedTimer _wallclock; | |
| 3419 bool _print_cr; | |
| 3420 | |
| 3421 public: | |
| 3422 // Not MT-safe; so do not pass around these StackObj's | |
| 3423 // where they may be accessed by other threads. | |
| 3424 jlong wallclock_millis() { | |
| 3425 assert(_wallclock.is_active(), "Wall clock should not stop"); | |
| 3426 _wallclock.stop(); // to record time | |
| 3427 jlong ret = _wallclock.milliseconds(); | |
| 3428 _wallclock.start(); // restart | |
| 3429 return ret; | |
| 3430 } | |
| 3431 }; | |
| 3432 | |
| 3433 CMSPhaseAccounting::CMSPhaseAccounting(CMSCollector *collector, | |
| 3434 const char *phase, | |
| 3435 bool print_cr) : | |
| 3436 _collector(collector), _phase(phase), _print_cr(print_cr) { | |
| 3437 | |
| 3438 if (PrintCMSStatistics != 0) { | |
| 3439 _collector->resetYields(); | |
| 3440 } | |
| 3441 if (PrintGCDetails && PrintGCTimeStamps) { | |
| 3442 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 3443 gclog_or_tty->stamp(); | |
| 3444 gclog_or_tty->print_cr(": [%s-concurrent-%s-start]", | |
| 3445 _collector->cmsGen()->short_name(), _phase); | |
| 3446 } | |
| 3447 _collector->resetTimer(); | |
| 3448 _wallclock.start(); | |
| 3449 _collector->startTimer(); | |
| 3450 } | |
| 3451 | |
| 3452 CMSPhaseAccounting::~CMSPhaseAccounting() { | |
| 3453 assert(_wallclock.is_active(), "Wall clock should not have stopped"); | |
| 3454 _collector->stopTimer(); | |
| 3455 _wallclock.stop(); | |
| 3456 if (PrintGCDetails) { | |
| 3457 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 3458 if (PrintGCTimeStamps) { | |
| 3459 gclog_or_tty->stamp(); | |
| 3460 gclog_or_tty->print(": "); | |
| 3461 } | |
| 3462 gclog_or_tty->print("[%s-concurrent-%s: %3.3f/%3.3f secs]", | |
| 3463 _collector->cmsGen()->short_name(), | |
| 3464 _phase, _collector->timerValue(), _wallclock.seconds()); | |
| 3465 if (_print_cr) { | |
| 3466 gclog_or_tty->print_cr(""); | |
| 3467 } | |
| 3468 if (PrintCMSStatistics != 0) { | |
| 3469 gclog_or_tty->print_cr(" (CMS-concurrent-%s yielded %d times)", _phase, | |
| 3470 _collector->yields()); | |
| 3471 } | |
| 3472 } | |
| 3473 } | |
| 3474 | |
| 3475 // CMS work | |
| 3476 | |
| 3477 // Checkpoint the roots into this generation from outside | |
| 3478 // this generation. [Note this initial checkpoint need only | |
| 3479 // be approximate -- we'll do a catch up phase subsequently.] | |
| 3480 void CMSCollector::checkpointRootsInitial(bool asynch) { | |
| 3481 assert(_collectorState == InitialMarking, "Wrong collector state"); | |
| 3482 check_correct_thread_executing(); | |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
3483 TraceCMSMemoryManagerStats tms(_collectorState,GenCollectedHeap::heap()->gc_cause()); |
|
2125
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1994
diff
changeset
|
3484 |
| 0 | 3485 ReferenceProcessor* rp = ref_processor(); |
| 3486 SpecializationStats::clear(); | |
| 3487 assert(_restart_addr == NULL, "Control point invariant"); | |
| 3488 if (asynch) { | |
| 3489 // acquire locks for subsequent manipulations | |
| 3490 MutexLockerEx x(bitMapLock(), | |
| 3491 Mutex::_no_safepoint_check_flag); | |
| 3492 checkpointRootsInitialWork(asynch); | |
|
3979
4dfb2df418f2
6484982: G1: process references during evacuation pauses
johnc
parents:
3827
diff
changeset
|
3493 // enable ("weak") refs discovery |
|
4dfb2df418f2
6484982: G1: process references during evacuation pauses
johnc
parents:
3827
diff
changeset
|
3494 rp->enable_discovery(true /*verify_disabled*/, true /*check_no_refs*/); |
| 0 | 3495 _collectorState = Marking; |
| 3496 } else { | |
| 3497 // (Weak) Refs discovery: this is controlled from genCollectedHeap::do_collection | |
| 3498 // which recognizes if we are a CMS generation, and doesn't try to turn on | |
| 3499 // discovery; verify that they aren't meddling. | |
| 3500 assert(!rp->discovery_is_atomic(), | |
| 3501 "incorrect setting of discovery predicate"); | |
| 3502 assert(!rp->discovery_enabled(), "genCollectedHeap shouldn't control " | |
| 3503 "ref discovery for this generation kind"); | |
| 3504 // already have locks | |
| 3505 checkpointRootsInitialWork(asynch); | |
|
3979
4dfb2df418f2
6484982: G1: process references during evacuation pauses
johnc
parents:
3827
diff
changeset
|
3506 // now enable ("weak") refs discovery |
|
4dfb2df418f2
6484982: G1: process references during evacuation pauses
johnc
parents:
3827
diff
changeset
|
3507 rp->enable_discovery(true /*verify_disabled*/, false /*verify_no_refs*/); |
| 0 | 3508 _collectorState = Marking; |
| 3509 } | |
| 3510 SpecializationStats::print(); | |
| 3511 } | |
| 3512 | |
| 3513 void CMSCollector::checkpointRootsInitialWork(bool asynch) { | |
| 3514 assert(SafepointSynchronize::is_at_safepoint(), "world should be stopped"); | |
| 3515 assert(_collectorState == InitialMarking, "just checking"); | |
| 3516 | |
| 3517 // If there has not been a GC[n-1] since last GC[n] cycle completed, | |
| 3518 // precede our marking with a collection of all | |
| 3519 // younger generations to keep floating garbage to a minimum. | |
| 3520 // XXX: we won't do this for now -- it's an optimization to be done later. | |
| 3521 | |
| 3522 // already have locks | |
| 3523 assert_lock_strong(bitMapLock()); | |
| 3524 assert(_markBitMap.isAllClear(), "was reset at end of previous cycle"); | |
| 3525 | |
| 3526 // Setup the verification and class unloading state for this | |
| 3527 // CMS collection cycle. | |
| 3528 setup_cms_unloading_and_verification_state(); | |
| 3529 | |
| 3530 NOT_PRODUCT(TraceTime t("\ncheckpointRootsInitialWork", | |
| 3531 PrintGCDetails && Verbose, true, gclog_or_tty);) | |
| 3532 if (UseAdaptiveSizePolicy) { | |
| 3533 size_policy()->checkpoint_roots_initial_begin(); | |
| 3534 } | |
| 3535 | |
| 3536 // Reset all the PLAB chunk arrays if necessary. | |
| 3537 if (_survivor_plab_array != NULL && !CMSPLABRecordAlways) { | |
| 3538 reset_survivor_plab_arrays(); | |
| 3539 } | |
| 3540 | |
| 3541 ResourceMark rm; | |
| 3542 HandleMark hm; | |
| 3543 | |
| 3544 FalseClosure falseClosure; | |
| 3545 // In the case of a synchronous collection, we will elide the | |
| 3546 // remark step, so it's important to catch all the nmethod oops | |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
3547 // in this step. |
|
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
3548 // The final 'true' flag to gen_process_strong_roots will ensure this. |
|
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
3549 // If 'async' is true, we can relax the nmethod tracing. |
|
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
3550 MarkRefsIntoClosure notOlder(_span, &_markBitMap); |
| 0 | 3551 GenCollectedHeap* gch = GenCollectedHeap::heap(); |
| 3552 | |
| 3553 verify_work_stacks_empty(); | |
| 3554 verify_overflow_empty(); | |
| 3555 | |
| 3556 gch->ensure_parsability(false); // fill TLABs, but no need to retire them | |
| 3557 // Update the saved marks which may affect the root scans. | |
| 3558 gch->save_marks(); | |
| 3559 | |
| 3560 // weak reference processing has not started yet. | |
| 3561 ref_processor()->set_enqueuing_is_done(false); | |
| 3562 | |
| 3563 { | |
| 935 | 3564 // This is not needed. DEBUG_ONLY(RememberKlassesChecker imx(true);) |
| 0 | 3565 COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact;) |
| 3566 gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel. | |
| 3567 gch->gen_process_strong_roots(_cmsGen->level(), | |
| 3568 true, // younger gens are roots | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
3569 true, // activate StrongRootsScope |
| 0 | 3570 true, // collecting perm gen |
| 3571 SharedHeap::ScanningOption(roots_scanning_options()), | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
3572 ¬Older, |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
3573 true, // walk all of code cache if (so & SO_CodeCache) |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
3574 NULL); |
| 0 | 3575 } |
| 3576 | |
| 3577 // Clear mod-union table; it will be dirtied in the prologue of | |
| 3578 // CMS generation per each younger generation collection. | |
| 3579 | |
| 3580 assert(_modUnionTable.isAllClear(), | |
| 3581 "Was cleared in most recent final checkpoint phase" | |
| 3582 " or no bits are set in the gc_prologue before the start of the next " | |
| 3583 "subsequent marking phase."); | |
| 3584 | |
| 3585 // Save the end of the used_region of the constituent generations | |
| 3586 // to be used to limit the extent of sweep in each generation. | |
| 3587 save_sweep_limits(); | |
| 3588 if (UseAdaptiveSizePolicy) { | |
| 3589 size_policy()->checkpoint_roots_initial_end(gch->gc_cause()); | |
| 3590 } | |
| 3591 verify_overflow_empty(); | |
| 3592 } | |
| 3593 | |
| 3594 bool CMSCollector::markFromRoots(bool asynch) { | |
| 3595 // we might be tempted to assert that: | |
| 3596 // assert(asynch == !SafepointSynchronize::is_at_safepoint(), | |
| 3597 // "inconsistent argument?"); | |
| 3598 // However that wouldn't be right, because it's possible that | |
| 3599 // a safepoint is indeed in progress as a younger generation | |
| 3600 // stop-the-world GC happens even as we mark in this generation. | |
| 3601 assert(_collectorState == Marking, "inconsistent state?"); | |
| 3602 check_correct_thread_executing(); | |
| 3603 verify_overflow_empty(); | |
| 3604 | |
| 3605 bool res; | |
| 3606 if (asynch) { | |
| 3607 | |
| 3608 // Start the timers for adaptive size policy for the concurrent phases | |
| 3609 // Do it here so that the foreground MS can use the concurrent | |
| 3610 // timer since a foreground MS might has the sweep done concurrently | |
| 3611 // or STW. | |
| 3612 if (UseAdaptiveSizePolicy) { | |
| 3613 size_policy()->concurrent_marking_begin(); | |
| 3614 } | |
| 3615 | |
| 3616 // Weak ref discovery note: We may be discovering weak | |
| 3617 // refs in this generation concurrent (but interleaved) with | |
| 3618 // weak ref discovery by a younger generation collector. | |
| 3619 | |
| 3620 CMSTokenSyncWithLocks ts(true, bitMapLock()); | |
| 3621 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 3622 CMSPhaseAccounting pa(this, "mark", !PrintGCDetails); | |
| 3623 res = markFromRootsWork(asynch); | |
| 3624 if (res) { | |
| 3625 _collectorState = Precleaning; | |
| 3626 } else { // We failed and a foreground collection wants to take over | |
| 3627 assert(_foregroundGCIsActive, "internal state inconsistency"); | |
| 3628 assert(_restart_addr == NULL, "foreground will restart from scratch"); | |
| 3629 if (PrintGCDetails) { | |
| 3630 gclog_or_tty->print_cr("bailing out to foreground collection"); | |
| 3631 } | |
| 3632 } | |
| 3633 if (UseAdaptiveSizePolicy) { | |
| 3634 size_policy()->concurrent_marking_end(); | |
| 3635 } | |
| 3636 } else { | |
| 3637 assert(SafepointSynchronize::is_at_safepoint(), | |
| 3638 "inconsistent with asynch == false"); | |
| 3639 if (UseAdaptiveSizePolicy) { | |
| 3640 size_policy()->ms_collection_marking_begin(); | |
| 3641 } | |
| 3642 // already have locks | |
| 3643 res = markFromRootsWork(asynch); | |
| 3644 _collectorState = FinalMarking; | |
| 3645 if (UseAdaptiveSizePolicy) { | |
| 3646 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 3647 size_policy()->ms_collection_marking_end(gch->gc_cause()); | |
| 3648 } | |
| 3649 } | |
| 3650 verify_overflow_empty(); | |
| 3651 return res; | |
| 3652 } | |
| 3653 | |
| 3654 bool CMSCollector::markFromRootsWork(bool asynch) { | |
| 3655 // iterate over marked bits in bit map, doing a full scan and mark | |
| 3656 // from these roots using the following algorithm: | |
| 3657 // . if oop is to the right of the current scan pointer, | |
| 3658 // mark corresponding bit (we'll process it later) | |
| 3659 // . else (oop is to left of current scan pointer) | |
| 3660 // push oop on marking stack | |
| 3661 // . drain the marking stack | |
| 3662 | |
| 3663 // Note that when we do a marking step we need to hold the | |
| 3664 // bit map lock -- recall that direct allocation (by mutators) | |
| 3665 // and promotion (by younger generation collectors) is also | |
| 3666 // marking the bit map. [the so-called allocate live policy.] | |
| 3667 // Because the implementation of bit map marking is not | |
| 3668 // robust wrt simultaneous marking of bits in the same word, | |
| 3669 // we need to make sure that there is no such interference | |
| 3670 // between concurrent such updates. | |
| 3671 | |
| 3672 // already have locks | |
| 3673 assert_lock_strong(bitMapLock()); | |
| 3674 | |
| 3675 // Clear the revisit stack, just in case there are any | |
| 3676 // obsolete contents from a short-circuited previous CMS cycle. | |
| 3677 _revisitStack.reset(); | |
| 3678 verify_work_stacks_empty(); | |
| 3679 verify_overflow_empty(); | |
| 3680 assert(_revisitStack.isEmpty(), "tabula rasa"); | |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
3681 DEBUG_ONLY(RememberKlassesChecker cmx(should_unload_classes());) |
| 0 | 3682 bool result = false; |
| 1284 | 3683 if (CMSConcurrentMTEnabled && ConcGCThreads > 0) { |
| 0 | 3684 result = do_marking_mt(asynch); |
| 3685 } else { | |
| 3686 result = do_marking_st(asynch); | |
| 3687 } | |
| 3688 return result; | |
| 3689 } | |
| 3690 | |
| 3691 // Forward decl | |
| 3692 class CMSConcMarkingTask; | |
| 3693 | |
| 3694 class CMSConcMarkingTerminator: public ParallelTaskTerminator { | |
| 3695 CMSCollector* _collector; | |
| 3696 CMSConcMarkingTask* _task; | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3697 public: |
| 0 | 3698 virtual void yield(); |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3699 |
| 0 | 3700 // "n_threads" is the number of threads to be terminated. |
| 3701 // "queue_set" is a set of work queues of other threads. | |
| 3702 // "collector" is the CMS collector associated with this task terminator. | |
| 3703 // "yield" indicates whether we need the gang as a whole to yield. | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3704 CMSConcMarkingTerminator(int n_threads, TaskQueueSetSuper* queue_set, CMSCollector* collector) : |
| 0 | 3705 ParallelTaskTerminator(n_threads, queue_set), |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3706 _collector(collector) { } |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3707 |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3708 void set_task(CMSConcMarkingTask* task) { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3709 _task = task; |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3710 } |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3711 }; |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3712 |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3713 class CMSConcMarkingTerminatorTerminator: public TerminatorTerminator { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3714 CMSConcMarkingTask* _task; |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3715 public: |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3716 bool should_exit_termination(); |
| 0 | 3717 void set_task(CMSConcMarkingTask* task) { |
| 3718 _task = task; | |
| 3719 } | |
| 3720 }; | |
| 3721 | |
| 3722 // MT Concurrent Marking Task | |
| 3723 class CMSConcMarkingTask: public YieldingFlexibleGangTask { | |
| 3724 CMSCollector* _collector; | |
| 3725 int _n_workers; // requested/desired # workers | |
| 3726 bool _asynch; | |
| 3727 bool _result; | |
| 3728 CompactibleFreeListSpace* _cms_space; | |
| 3729 CompactibleFreeListSpace* _perm_space; | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3730 char _pad_front[64]; // padding to ... |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3731 HeapWord* _global_finger; // ... avoid sharing cache line |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3732 char _pad_back[64]; |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3733 HeapWord* _restart_addr; |
| 0 | 3734 |
| 3735 // Exposed here for yielding support | |
| 3736 Mutex* const _bit_map_lock; | |
| 3737 | |
| 3738 // The per thread work queues, available here for stealing | |
| 3739 OopTaskQueueSet* _task_queues; | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3740 |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3741 // Termination (and yielding) support |
| 0 | 3742 CMSConcMarkingTerminator _term; |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3743 CMSConcMarkingTerminatorTerminator _term_term; |
| 0 | 3744 |
| 3745 public: | |
| 3746 CMSConcMarkingTask(CMSCollector* collector, | |
| 3747 CompactibleFreeListSpace* cms_space, | |
| 3748 CompactibleFreeListSpace* perm_space, | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3749 bool asynch, |
| 0 | 3750 YieldingFlexibleWorkGang* workers, |
| 3751 OopTaskQueueSet* task_queues): | |
| 3752 YieldingFlexibleGangTask("Concurrent marking done multi-threaded"), | |
| 3753 _collector(collector), | |
| 3754 _cms_space(cms_space), | |
| 3755 _perm_space(perm_space), | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3756 _asynch(asynch), _n_workers(0), _result(true), |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3757 _task_queues(task_queues), |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3758 _term(_n_workers, task_queues, _collector), |
| 0 | 3759 _bit_map_lock(collector->bitMapLock()) |
| 3760 { | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3761 _requested_size = _n_workers; |
| 0 | 3762 _term.set_task(this); |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3763 _term_term.set_task(this); |
| 0 | 3764 assert(_cms_space->bottom() < _perm_space->bottom(), |
| 3765 "Finger incorrectly initialized below"); | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3766 _restart_addr = _global_finger = _cms_space->bottom(); |
| 0 | 3767 } |
| 3768 | |
| 3769 | |
| 3770 OopTaskQueueSet* task_queues() { return _task_queues; } | |
| 3771 | |
| 3772 OopTaskQueue* work_queue(int i) { return task_queues()->queue(i); } | |
| 3773 | |
| 3774 HeapWord** global_finger_addr() { return &_global_finger; } | |
| 3775 | |
| 3776 CMSConcMarkingTerminator* terminator() { return &_term; } | |
| 3777 | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3778 virtual void set_for_termination(int active_workers) { |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3779 terminator()->reset_for_reuse(active_workers); |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3780 } |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3781 |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3782 void work(uint worker_id); |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3783 bool should_yield() { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3784 return ConcurrentMarkSweepThread::should_yield() |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3785 && !_collector->foregroundGCIsActive() |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3786 && _asynch; |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3787 } |
| 0 | 3788 |
| 3789 virtual void coordinator_yield(); // stuff done by coordinator | |
| 3790 bool result() { return _result; } | |
| 3791 | |
| 3792 void reset(HeapWord* ra) { | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3793 assert(_global_finger >= _cms_space->end(), "Postcondition of ::work(i)"); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3794 assert(_global_finger >= _perm_space->end(), "Postcondition of ::work(i)"); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3795 assert(ra < _perm_space->end(), "ra too large"); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3796 _restart_addr = _global_finger = ra; |
| 0 | 3797 _term.reset_for_reuse(); |
| 3798 } | |
| 3799 | |
| 3800 static bool get_work_from_overflow_stack(CMSMarkStack* ovflw_stk, | |
| 3801 OopTaskQueue* work_q); | |
| 3802 | |
| 3803 private: | |
| 3804 void do_scan_and_mark(int i, CompactibleFreeListSpace* sp); | |
| 3805 void do_work_steal(int i); | |
| 3806 void bump_global_finger(HeapWord* f); | |
| 3807 }; | |
| 3808 | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3809 bool CMSConcMarkingTerminatorTerminator::should_exit_termination() { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3810 assert(_task != NULL, "Error"); |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3811 return _task->yielding(); |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3812 // Note that we do not need the disjunct || _task->should_yield() above |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3813 // because we want terminating threads to yield only if the task |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3814 // is already in the midst of yielding, which happens only after at least one |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3815 // thread has yielded. |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3816 } |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3817 |
| 0 | 3818 void CMSConcMarkingTerminator::yield() { |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
3819 if (_task->should_yield()) { |
| 0 | 3820 _task->yield(); |
| 3821 } else { | |
| 3822 ParallelTaskTerminator::yield(); | |
| 3823 } | |
| 3824 } | |
| 3825 | |
| 3826 //////////////////////////////////////////////////////////////// | |
| 3827 // Concurrent Marking Algorithm Sketch | |
| 3828 //////////////////////////////////////////////////////////////// | |
| 3829 // Until all tasks exhausted (both spaces): | |
| 3830 // -- claim next available chunk | |
| 3831 // -- bump global finger via CAS | |
| 3832 // -- find first object that starts in this chunk | |
| 3833 // and start scanning bitmap from that position | |
| 3834 // -- scan marked objects for oops | |
| 3835 // -- CAS-mark target, and if successful: | |
| 3836 // . if target oop is above global finger (volatile read) | |
| 3837 // nothing to do | |
| 3838 // . if target oop is in chunk and above local finger | |
| 3839 // then nothing to do | |
| 3840 // . else push on work-queue | |
| 3841 // -- Deal with possible overflow issues: | |
| 3842 // . local work-queue overflow causes stuff to be pushed on | |
| 3843 // global (common) overflow queue | |
| 3844 // . always first empty local work queue | |
| 3845 // . then get a batch of oops from global work queue if any | |
| 3846 // . then do work stealing | |
| 3847 // -- When all tasks claimed (both spaces) | |
| 3848 // and local work queue empty, | |
| 3849 // then in a loop do: | |
| 3850 // . check global overflow stack; steal a batch of oops and trace | |
| 3851 // . try to steal from other threads oif GOS is empty | |
| 3852 // . if neither is available, offer termination | |
| 3853 // -- Terminate and return result | |
| 3854 // | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3855 void CMSConcMarkingTask::work(uint worker_id) { |
| 0 | 3856 elapsedTimer _timer; |
| 3857 ResourceMark rm; | |
| 3858 HandleMark hm; | |
| 3859 | |
| 3860 DEBUG_ONLY(_collector->verify_overflow_empty();) | |
| 3861 | |
| 3862 // Before we begin work, our work queue should be empty | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3863 assert(work_queue(worker_id)->size() == 0, "Expected to be empty"); |
| 0 | 3864 // Scan the bitmap covering _cms_space, tracing through grey objects. |
| 3865 _timer.start(); | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3866 do_scan_and_mark(worker_id, _cms_space); |
| 0 | 3867 _timer.stop(); |
| 3868 if (PrintCMSStatistics != 0) { | |
| 3869 gclog_or_tty->print_cr("Finished cms space scanning in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3870 worker_id, _timer.seconds()); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3871 // XXX: need xxx/xxx type of notation, two timers |
| 0 | 3872 } |
| 3873 | |
| 3874 // ... do the same for the _perm_space | |
| 3875 _timer.reset(); | |
| 3876 _timer.start(); | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3877 do_scan_and_mark(worker_id, _perm_space); |
| 0 | 3878 _timer.stop(); |
| 3879 if (PrintCMSStatistics != 0) { | |
| 3880 gclog_or_tty->print_cr("Finished perm space scanning in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3881 worker_id, _timer.seconds()); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3882 // XXX: need xxx/xxx type of notation, two timers |
| 0 | 3883 } |
| 3884 | |
| 3885 // ... do work stealing | |
| 3886 _timer.reset(); | |
| 3887 _timer.start(); | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3888 do_work_steal(worker_id); |
| 0 | 3889 _timer.stop(); |
| 3890 if (PrintCMSStatistics != 0) { | |
| 3891 gclog_or_tty->print_cr("Finished work stealing in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3892 worker_id, _timer.seconds()); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3893 // XXX: need xxx/xxx type of notation, two timers |
| 0 | 3894 } |
| 3895 assert(_collector->_markStack.isEmpty(), "Should have been emptied"); | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3896 assert(work_queue(worker_id)->size() == 0, "Should have been emptied"); |
| 0 | 3897 // Note that under the current task protocol, the |
| 3898 // following assertion is true even of the spaces | |
| 3899 // expanded since the completion of the concurrent | |
| 3900 // marking. XXX This will likely change under a strict | |
| 3901 // ABORT semantics. | |
| 3902 assert(_global_finger > _cms_space->end() && | |
| 3903 _global_finger >= _perm_space->end(), | |
| 3904 "All tasks have been completed"); | |
| 3905 DEBUG_ONLY(_collector->verify_overflow_empty();) | |
| 3906 } | |
| 3907 | |
| 3908 void CMSConcMarkingTask::bump_global_finger(HeapWord* f) { | |
| 3909 HeapWord* read = _global_finger; | |
| 3910 HeapWord* cur = read; | |
| 3911 while (f > read) { | |
| 3912 cur = read; | |
| 3913 read = (HeapWord*) Atomic::cmpxchg_ptr(f, &_global_finger, cur); | |
| 3914 if (cur == read) { | |
| 3915 // our cas succeeded | |
| 3916 assert(_global_finger >= f, "protocol consistency"); | |
| 3917 break; | |
| 3918 } | |
| 3919 } | |
| 3920 } | |
| 3921 | |
| 3922 // This is really inefficient, and should be redone by | |
| 3923 // using (not yet available) block-read and -write interfaces to the | |
| 3924 // stack and the work_queue. XXX FIX ME !!! | |
| 3925 bool CMSConcMarkingTask::get_work_from_overflow_stack(CMSMarkStack* ovflw_stk, | |
| 3926 OopTaskQueue* work_q) { | |
| 3927 // Fast lock-free check | |
| 3928 if (ovflw_stk->length() == 0) { | |
| 3929 return false; | |
| 3930 } | |
| 3931 assert(work_q->size() == 0, "Shouldn't steal"); | |
| 3932 MutexLockerEx ml(ovflw_stk->par_lock(), | |
| 3933 Mutex::_no_safepoint_check_flag); | |
| 3934 // Grab up to 1/4 the size of the work queue | |
|
679
cea947c8a988
6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops
ysr
parents:
628
diff
changeset
|
3935 size_t num = MIN2((size_t)(work_q->max_elems() - work_q->size())/4, |
| 0 | 3936 (size_t)ParGCDesiredObjsFromOverflowList); |
| 3937 num = MIN2(num, ovflw_stk->length()); | |
| 3938 for (int i = (int) num; i > 0; i--) { | |
| 3939 oop cur = ovflw_stk->pop(); | |
| 3940 assert(cur != NULL, "Counted wrong?"); | |
| 3941 work_q->push(cur); | |
| 3942 } | |
| 3943 return num > 0; | |
| 3944 } | |
| 3945 | |
| 3946 void CMSConcMarkingTask::do_scan_and_mark(int i, CompactibleFreeListSpace* sp) { | |
| 3947 SequentialSubTasksDone* pst = sp->conc_par_seq_tasks(); | |
| 3948 int n_tasks = pst->n_tasks(); | |
| 3949 // We allow that there may be no tasks to do here because | |
| 3950 // we are restarting after a stack overflow. | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3951 assert(pst->valid() || n_tasks == 0, "Uninitialized use?"); |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
3952 uint nth_task = 0; |
| 0 | 3953 |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3954 HeapWord* aligned_start = sp->bottom(); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3955 if (sp->used_region().contains(_restart_addr)) { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3956 // Align down to a card boundary for the start of 0th task |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3957 // for this space. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3958 aligned_start = |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3959 (HeapWord*)align_size_down((uintptr_t)_restart_addr, |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3960 CardTableModRefBS::card_size); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3961 } |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3962 |
| 0 | 3963 size_t chunk_size = sp->marking_task_size(); |
| 3964 while (!pst->is_task_claimed(/* reference */ nth_task)) { | |
| 3965 // Having claimed the nth task in this space, | |
| 3966 // compute the chunk that it corresponds to: | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3967 MemRegion span = MemRegion(aligned_start + nth_task*chunk_size, |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3968 aligned_start + (nth_task+1)*chunk_size); |
| 0 | 3969 // Try and bump the global finger via a CAS; |
| 3970 // note that we need to do the global finger bump | |
| 3971 // _before_ taking the intersection below, because | |
| 3972 // the task corresponding to that region will be | |
| 3973 // deemed done even if the used_region() expands | |
| 3974 // because of allocation -- as it almost certainly will | |
| 3975 // during start-up while the threads yield in the | |
| 3976 // closure below. | |
| 3977 HeapWord* finger = span.end(); | |
| 3978 bump_global_finger(finger); // atomically | |
| 3979 // There are null tasks here corresponding to chunks | |
| 3980 // beyond the "top" address of the space. | |
| 3981 span = span.intersection(sp->used_region()); | |
| 3982 if (!span.is_empty()) { // Non-null task | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3983 HeapWord* prev_obj; |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3984 assert(!span.contains(_restart_addr) || nth_task == 0, |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3985 "Inconsistency"); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3986 if (nth_task == 0) { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3987 // For the 0th task, we'll not need to compute a block_start. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3988 if (span.contains(_restart_addr)) { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3989 // In the case of a restart because of stack overflow, |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3990 // we might additionally skip a chunk prefix. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3991 prev_obj = _restart_addr; |
| 0 | 3992 } else { |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3993 prev_obj = span.start(); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3994 } |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3995 } else { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3996 // We want to skip the first object because |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3997 // the protocol is to scan any object in its entirety |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3998 // that _starts_ in this span; a fortiori, any |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
3999 // object starting in an earlier span is scanned |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4000 // as part of an earlier claimed task. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4001 // Below we use the "careful" version of block_start |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4002 // so we do not try to navigate uninitialized objects. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4003 prev_obj = sp->block_start_careful(span.start()); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4004 // Below we use a variant of block_size that uses the |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4005 // Printezis bits to avoid waiting for allocated |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4006 // objects to become initialized/parsable. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4007 while (prev_obj < span.start()) { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4008 size_t sz = sp->block_size_no_stall(prev_obj, _collector); |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4009 if (sz > 0) { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4010 prev_obj += sz; |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4011 } else { |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4012 // In this case we may end up doing a bit of redundant |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4013 // scanning, but that appears unavoidable, short of |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4014 // locking the free list locks; see bug 6324141. |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4015 break; |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4016 } |
| 0 | 4017 } |
| 4018 } | |
| 4019 if (prev_obj < span.end()) { | |
| 4020 MemRegion my_span = MemRegion(prev_obj, span.end()); | |
| 4021 // Do the marking work within a non-empty span -- | |
| 4022 // the last argument to the constructor indicates whether the | |
| 4023 // iteration should be incremental with periodic yields. | |
| 4024 Par_MarkFromRootsClosure cl(this, _collector, my_span, | |
| 4025 &_collector->_markBitMap, | |
| 4026 work_queue(i), | |
| 4027 &_collector->_markStack, | |
| 4028 &_collector->_revisitStack, | |
| 4029 _asynch); | |
| 4030 _collector->_markBitMap.iterate(&cl, my_span.start(), my_span.end()); | |
| 4031 } // else nothing to do for this task | |
| 4032 } // else nothing to do for this task | |
| 4033 } | |
| 4034 // We'd be tempted to assert here that since there are no | |
| 4035 // more tasks left to claim in this space, the global_finger | |
| 4036 // must exceed space->top() and a fortiori space->end(). However, | |
| 4037 // that would not quite be correct because the bumping of | |
| 4038 // global_finger occurs strictly after the claiming of a task, | |
| 4039 // so by the time we reach here the global finger may not yet | |
| 4040 // have been bumped up by the thread that claimed the last | |
| 4041 // task. | |
| 4042 pst->all_tasks_completed(); | |
| 4043 } | |
| 4044 | |
| 935 | 4045 class Par_ConcMarkingClosure: public Par_KlassRememberingOopClosure { |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4046 private: |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4047 CMSConcMarkingTask* _task; |
| 0 | 4048 MemRegion _span; |
| 4049 CMSBitMap* _bit_map; | |
| 4050 CMSMarkStack* _overflow_stack; | |
| 4051 OopTaskQueue* _work_queue; | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4052 protected: |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4053 DO_OOP_WORK_DEFN |
| 0 | 4054 public: |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4055 Par_ConcMarkingClosure(CMSCollector* collector, CMSConcMarkingTask* task, OopTaskQueue* work_queue, |
| 935 | 4056 CMSBitMap* bit_map, CMSMarkStack* overflow_stack, |
| 4057 CMSMarkStack* revisit_stack): | |
|
4128
f1391adc6681
7112034: Parallel CMS fails to properly mark reference objects
stefank
parents:
4098
diff
changeset
|
4058 Par_KlassRememberingOopClosure(collector, collector->ref_processor(), revisit_stack), |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4059 _task(task), |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4060 _span(collector->_span), |
| 0 | 4061 _work_queue(work_queue), |
| 4062 _bit_map(bit_map), | |
| 935 | 4063 _overflow_stack(overflow_stack) |
| 4064 { } | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4065 virtual void do_oop(oop* p); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4066 virtual void do_oop(narrowOop* p); |
| 0 | 4067 void trim_queue(size_t max); |
| 4068 void handle_stack_overflow(HeapWord* lost); | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4069 void do_yield_check() { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4070 if (_task->should_yield()) { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4071 _task->yield(); |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4072 } |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4073 } |
| 0 | 4074 }; |
| 4075 | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4076 // Grey object scanning during work stealing phase -- |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4077 // the salient assumption here is that any references |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4078 // that are in these stolen objects being scanned must |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4079 // already have been initialized (else they would not have |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4080 // been published), so we do not need to check for |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4081 // uninitialized objects before pushing here. |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4082 void Par_ConcMarkingClosure::do_oop(oop obj) { |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4083 assert(obj->is_oop_or_null(true), "expected an oop or NULL"); |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4084 HeapWord* addr = (HeapWord*)obj; |
| 0 | 4085 // Check if oop points into the CMS generation |
| 4086 // and is not marked | |
| 4087 if (_span.contains(addr) && !_bit_map->isMarked(addr)) { | |
| 4088 // a white object ... | |
| 4089 // If we manage to "claim" the object, by being the | |
| 4090 // first thread to mark it, then we push it on our | |
| 4091 // marking stack | |
| 4092 if (_bit_map->par_mark(addr)) { // ... now grey | |
| 4093 // push on work queue (grey set) | |
| 4094 bool simulate_overflow = false; | |
| 4095 NOT_PRODUCT( | |
| 4096 if (CMSMarkStackOverflowALot && | |
| 4097 _collector->simulate_overflow()) { | |
| 4098 // simulate a stack overflow | |
| 4099 simulate_overflow = true; | |
| 4100 } | |
| 4101 ) | |
| 4102 if (simulate_overflow || | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4103 !(_work_queue->push(obj) || _overflow_stack->par_push(obj))) { |
| 0 | 4104 // stack overflow |
| 4105 if (PrintCMSStatistics != 0) { | |
| 4106 gclog_or_tty->print_cr("CMS marking stack overflow (benign) at " | |
| 4107 SIZE_FORMAT, _overflow_stack->capacity()); | |
| 4108 } | |
| 4109 // We cannot assert that the overflow stack is full because | |
| 4110 // it may have been emptied since. | |
| 4111 assert(simulate_overflow || | |
| 4112 _work_queue->size() == _work_queue->max_elems(), | |
| 4113 "Else push should have succeeded"); | |
| 4114 handle_stack_overflow(addr); | |
| 4115 } | |
| 4116 } // Else, some other thread got there first | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4117 do_yield_check(); |
| 0 | 4118 } |
| 4119 } | |
| 4120 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4121 void Par_ConcMarkingClosure::do_oop(oop* p) { Par_ConcMarkingClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4122 void Par_ConcMarkingClosure::do_oop(narrowOop* p) { Par_ConcMarkingClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4123 |
| 0 | 4124 void Par_ConcMarkingClosure::trim_queue(size_t max) { |
| 4125 while (_work_queue->size() > max) { | |
| 4126 oop new_oop; | |
| 4127 if (_work_queue->pop_local(new_oop)) { | |
| 4128 assert(new_oop->is_oop(), "Should be an oop"); | |
| 4129 assert(_bit_map->isMarked((HeapWord*)new_oop), "Grey object"); | |
| 4130 assert(_span.contains((HeapWord*)new_oop), "Not in span"); | |
| 4131 assert(new_oop->is_parsable(), "Should be parsable"); | |
| 4132 new_oop->oop_iterate(this); // do_oop() above | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4133 do_yield_check(); |
| 0 | 4134 } |
| 4135 } | |
| 4136 } | |
| 4137 | |
| 4138 // Upon stack overflow, we discard (part of) the stack, | |
| 4139 // remembering the least address amongst those discarded | |
| 4140 // in CMSCollector's _restart_address. | |
| 4141 void Par_ConcMarkingClosure::handle_stack_overflow(HeapWord* lost) { | |
| 4142 // We need to do this under a mutex to prevent other | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
4143 // workers from interfering with the work done below. |
| 0 | 4144 MutexLockerEx ml(_overflow_stack->par_lock(), |
| 4145 Mutex::_no_safepoint_check_flag); | |
| 4146 // Remember the least grey address discarded | |
| 4147 HeapWord* ra = (HeapWord*)_overflow_stack->least_value(lost); | |
| 4148 _collector->lower_restart_addr(ra); | |
| 4149 _overflow_stack->reset(); // discard stack contents | |
| 4150 _overflow_stack->expand(); // expand the stack if possible | |
| 4151 } | |
| 4152 | |
| 4153 | |
| 4154 void CMSConcMarkingTask::do_work_steal(int i) { | |
| 4155 OopTaskQueue* work_q = work_queue(i); | |
| 4156 oop obj_to_scan; | |
| 4157 CMSBitMap* bm = &(_collector->_markBitMap); | |
| 4158 CMSMarkStack* ovflw = &(_collector->_markStack); | |
| 935 | 4159 CMSMarkStack* revisit = &(_collector->_revisitStack); |
| 0 | 4160 int* seed = _collector->hash_seed(i); |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4161 Par_ConcMarkingClosure cl(_collector, this, work_q, bm, ovflw, revisit); |
| 0 | 4162 while (true) { |
| 4163 cl.trim_queue(0); | |
| 4164 assert(work_q->size() == 0, "Should have been emptied above"); | |
| 4165 if (get_work_from_overflow_stack(ovflw, work_q)) { | |
| 4166 // Can't assert below because the work obtained from the | |
| 4167 // overflow stack may already have been stolen from us. | |
| 4168 // assert(work_q->size() > 0, "Work from overflow stack"); | |
| 4169 continue; | |
| 4170 } else if (task_queues()->steal(i, seed, /* reference */ obj_to_scan)) { | |
| 4171 assert(obj_to_scan->is_oop(), "Should be an oop"); | |
| 4172 assert(bm->isMarked((HeapWord*)obj_to_scan), "Grey object"); | |
| 4173 obj_to_scan->oop_iterate(&cl); | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4174 } else if (terminator()->offer_termination(&_term_term)) { |
| 0 | 4175 assert(work_q->size() == 0, "Impossible!"); |
| 4176 break; | |
|
1837
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4177 } else if (yielding() || should_yield()) { |
|
c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
ysr
parents:
1836
diff
changeset
|
4178 yield(); |
| 0 | 4179 } |
| 4180 } | |
| 4181 } | |
| 4182 | |
| 4183 // This is run by the CMS (coordinator) thread. | |
| 4184 void CMSConcMarkingTask::coordinator_yield() { | |
| 4185 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 4186 "CMS thread should hold CMS token"); | |
| 935 | 4187 DEBUG_ONLY(RememberKlassesChecker mux(false);) |
| 0 | 4188 // First give up the locks, then yield, then re-lock |
| 4189 // We should probably use a constructor/destructor idiom to | |
| 4190 // do this unlock/lock or modify the MutexUnlocker class to | |
| 4191 // serve our purpose. XXX | |
| 4192 assert_lock_strong(_bit_map_lock); | |
| 4193 _bit_map_lock->unlock(); | |
| 4194 ConcurrentMarkSweepThread::desynchronize(true); | |
| 4195 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 4196 _collector->stopTimer(); | |
| 4197 if (PrintCMSStatistics != 0) { | |
| 4198 _collector->incrementYields(); | |
| 4199 } | |
| 4200 _collector->icms_wait(); | |
| 4201 | |
| 4202 // It is possible for whichever thread initiated the yield request | |
| 4203 // not to get a chance to wake up and take the bitmap lock between | |
| 4204 // this thread releasing it and reacquiring it. So, while the | |
| 4205 // should_yield() flag is on, let's sleep for a bit to give the | |
| 4206 // other thread a chance to wake up. The limit imposed on the number | |
| 4207 // of iterations is defensive, to avoid any unforseen circumstances | |
| 4208 // putting us into an infinite loop. Since it's always been this | |
| 4209 // (coordinator_yield()) method that was observed to cause the | |
| 4210 // problem, we are using a parameter (CMSCoordinatorYieldSleepCount) | |
| 4211 // which is by default non-zero. For the other seven methods that | |
| 4212 // also perform the yield operation, as are using a different | |
| 4213 // parameter (CMSYieldSleepCount) which is by default zero. This way we | |
| 4214 // can enable the sleeping for those methods too, if necessary. | |
| 4215 // See 6442774. | |
| 4216 // | |
| 4217 // We really need to reconsider the synchronization between the GC | |
| 4218 // thread and the yield-requesting threads in the future and we | |
| 4219 // should really use wait/notify, which is the recommended | |
| 4220 // way of doing this type of interaction. Additionally, we should | |
| 4221 // consolidate the eight methods that do the yield operation and they | |
| 4222 // are almost identical into one for better maintenability and | |
| 4223 // readability. See 6445193. | |
| 4224 // | |
| 4225 // Tony 2006.06.29 | |
| 4226 for (unsigned i = 0; i < CMSCoordinatorYieldSleepCount && | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4227 ConcurrentMarkSweepThread::should_yield() && |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
4228 !CMSCollector::foregroundGCIsActive(); ++i) { |
| 0 | 4229 os::sleep(Thread::current(), 1, false); |
| 4230 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 4231 } | |
| 4232 | |
| 4233 ConcurrentMarkSweepThread::synchronize(true); | |
| 4234 _bit_map_lock->lock_without_safepoint_check(); | |
| 4235 _collector->startTimer(); | |
| 4236 } | |
| 4237 | |
| 4238 bool CMSCollector::do_marking_mt(bool asynch) { | |
| 1284 | 4239 assert(ConcGCThreads > 0 && conc_workers() != NULL, "precondition"); |
|
4095
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
4240 int num_workers = AdaptiveSizePolicy::calc_active_conc_workers( |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
4241 conc_workers()->total_workers(), |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
4242 conc_workers()->active_workers(), |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
4243 Threads::number_of_non_daemon_threads()); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
4244 conc_workers()->set_active_workers(num_workers); |
| 0 | 4245 |
| 4246 CompactibleFreeListSpace* cms_space = _cmsGen->cmsSpace(); | |
| 4247 CompactibleFreeListSpace* perm_space = _permGen->cmsSpace(); | |
| 4248 | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4249 CMSConcMarkingTask tsk(this, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4250 cms_space, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4251 perm_space, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4252 asynch, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4253 conc_workers(), |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4254 task_queues()); |
| 0 | 4255 |
| 4256 // Since the actual number of workers we get may be different | |
| 4257 // from the number we requested above, do we need to do anything different | |
| 4258 // below? In particular, may be we need to subclass the SequantialSubTasksDone | |
| 4259 // class?? XXX | |
| 4260 cms_space ->initialize_sequential_subtasks_for_marking(num_workers); | |
| 4261 perm_space->initialize_sequential_subtasks_for_marking(num_workers); | |
| 4262 | |
| 4263 // Refs discovery is already non-atomic. | |
| 4264 assert(!ref_processor()->discovery_is_atomic(), "Should be non-atomic"); | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4265 assert(ref_processor()->discovery_is_mt(), "Discovery should be MT"); |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
4266 DEBUG_ONLY(RememberKlassesChecker cmx(should_unload_classes());) |
| 0 | 4267 conc_workers()->start_task(&tsk); |
| 4268 while (tsk.yielded()) { | |
| 4269 tsk.coordinator_yield(); | |
| 4270 conc_workers()->continue_task(&tsk); | |
| 4271 } | |
| 4272 // If the task was aborted, _restart_addr will be non-NULL | |
| 4273 assert(tsk.completed() || _restart_addr != NULL, "Inconsistency"); | |
| 4274 while (_restart_addr != NULL) { | |
| 4275 // XXX For now we do not make use of ABORTED state and have not | |
| 4276 // yet implemented the right abort semantics (even in the original | |
| 4277 // single-threaded CMS case). That needs some more investigation | |
| 4278 // and is deferred for now; see CR# TBF. 07252005YSR. XXX | |
| 4279 assert(!CMSAbortSemantics || tsk.aborted(), "Inconsistency"); | |
| 4280 // If _restart_addr is non-NULL, a marking stack overflow | |
| 605 | 4281 // occurred; we need to do a fresh marking iteration from the |
| 0 | 4282 // indicated restart address. |
| 4283 if (_foregroundGCIsActive && asynch) { | |
| 4284 // We may be running into repeated stack overflows, having | |
| 4285 // reached the limit of the stack size, while making very | |
| 4286 // slow forward progress. It may be best to bail out and | |
| 4287 // let the foreground collector do its job. | |
| 4288 // Clear _restart_addr, so that foreground GC | |
| 4289 // works from scratch. This avoids the headache of | |
| 4290 // a "rescan" which would otherwise be needed because | |
| 4291 // of the dirty mod union table & card table. | |
| 4292 _restart_addr = NULL; | |
| 4293 return false; | |
| 4294 } | |
| 4295 // Adjust the task to restart from _restart_addr | |
| 4296 tsk.reset(_restart_addr); | |
| 4297 cms_space ->initialize_sequential_subtasks_for_marking(num_workers, | |
| 4298 _restart_addr); | |
| 4299 perm_space->initialize_sequential_subtasks_for_marking(num_workers, | |
| 4300 _restart_addr); | |
| 4301 _restart_addr = NULL; | |
| 4302 // Get the workers going again | |
| 4303 conc_workers()->start_task(&tsk); | |
| 4304 while (tsk.yielded()) { | |
| 4305 tsk.coordinator_yield(); | |
| 4306 conc_workers()->continue_task(&tsk); | |
| 4307 } | |
| 4308 } | |
| 4309 assert(tsk.completed(), "Inconsistency"); | |
| 4310 assert(tsk.result() == true, "Inconsistency"); | |
| 4311 return true; | |
| 4312 } | |
| 4313 | |
| 4314 bool CMSCollector::do_marking_st(bool asynch) { | |
| 4315 ResourceMark rm; | |
| 4316 HandleMark hm; | |
| 4317 | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4318 // Temporarily make refs discovery single threaded (non-MT) |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4319 ReferenceProcessorMTDiscoveryMutator rp_mut_discovery(ref_processor(), false); |
| 0 | 4320 MarkFromRootsClosure markFromRootsClosure(this, _span, &_markBitMap, |
| 4321 &_markStack, &_revisitStack, CMSYield && asynch); | |
| 4322 // the last argument to iterate indicates whether the iteration | |
| 4323 // should be incremental with periodic yields. | |
| 4324 _markBitMap.iterate(&markFromRootsClosure); | |
| 4325 // If _restart_addr is non-NULL, a marking stack overflow | |
| 605 | 4326 // occurred; we need to do a fresh iteration from the |
| 0 | 4327 // indicated restart address. |
| 4328 while (_restart_addr != NULL) { | |
| 4329 if (_foregroundGCIsActive && asynch) { | |
| 4330 // We may be running into repeated stack overflows, having | |
| 4331 // reached the limit of the stack size, while making very | |
| 4332 // slow forward progress. It may be best to bail out and | |
| 4333 // let the foreground collector do its job. | |
| 4334 // Clear _restart_addr, so that foreground GC | |
| 4335 // works from scratch. This avoids the headache of | |
| 4336 // a "rescan" which would otherwise be needed because | |
| 4337 // of the dirty mod union table & card table. | |
| 4338 _restart_addr = NULL; | |
| 4339 return false; // indicating failure to complete marking | |
| 4340 } | |
| 4341 // Deal with stack overflow: | |
| 4342 // we restart marking from _restart_addr | |
| 4343 HeapWord* ra = _restart_addr; | |
| 4344 markFromRootsClosure.reset(ra); | |
| 4345 _restart_addr = NULL; | |
| 4346 _markBitMap.iterate(&markFromRootsClosure, ra, _span.end()); | |
| 4347 } | |
| 4348 return true; | |
| 4349 } | |
| 4350 | |
| 4351 void CMSCollector::preclean() { | |
| 4352 check_correct_thread_executing(); | |
| 4353 assert(Thread::current()->is_ConcurrentGC_thread(), "Wrong thread"); | |
| 4354 verify_work_stacks_empty(); | |
| 4355 verify_overflow_empty(); | |
| 4356 _abort_preclean = false; | |
| 4357 if (CMSPrecleaningEnabled) { | |
| 4358 _eden_chunk_index = 0; | |
| 4359 size_t used = get_eden_used(); | |
| 4360 size_t capacity = get_eden_capacity(); | |
| 4361 // Don't start sampling unless we will get sufficiently | |
| 4362 // many samples. | |
| 4363 if (used < (capacity/(CMSScheduleRemarkSamplingRatio * 100) | |
| 4364 * CMSScheduleRemarkEdenPenetration)) { | |
| 4365 _start_sampling = true; | |
| 4366 } else { | |
| 4367 _start_sampling = false; | |
| 4368 } | |
| 4369 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 4370 CMSPhaseAccounting pa(this, "preclean", !PrintGCDetails); | |
| 4371 preclean_work(CMSPrecleanRefLists1, CMSPrecleanSurvivors1); | |
| 4372 } | |
| 4373 CMSTokenSync x(true); // is cms thread | |
| 4374 if (CMSPrecleaningEnabled) { | |
| 4375 sample_eden(); | |
| 4376 _collectorState = AbortablePreclean; | |
| 4377 } else { | |
| 4378 _collectorState = FinalMarking; | |
| 4379 } | |
| 4380 verify_work_stacks_empty(); | |
| 4381 verify_overflow_empty(); | |
| 4382 } | |
| 4383 | |
| 4384 // Try and schedule the remark such that young gen | |
| 4385 // occupancy is CMSScheduleRemarkEdenPenetration %. | |
| 4386 void CMSCollector::abortable_preclean() { | |
| 4387 check_correct_thread_executing(); | |
| 4388 assert(CMSPrecleaningEnabled, "Inconsistent control state"); | |
| 4389 assert(_collectorState == AbortablePreclean, "Inconsistent control state"); | |
| 4390 | |
| 4391 // If Eden's current occupancy is below this threshold, | |
| 4392 // immediately schedule the remark; else preclean | |
| 4393 // past the next scavenge in an effort to | |
| 4394 // schedule the pause as described avove. By choosing | |
| 4395 // CMSScheduleRemarkEdenSizeThreshold >= max eden size | |
| 4396 // we will never do an actual abortable preclean cycle. | |
| 4397 if (get_eden_used() > CMSScheduleRemarkEdenSizeThreshold) { | |
| 4398 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 4399 CMSPhaseAccounting pa(this, "abortable-preclean", !PrintGCDetails); | |
| 4400 // We need more smarts in the abortable preclean | |
| 4401 // loop below to deal with cases where allocation | |
| 4402 // in young gen is very very slow, and our precleaning | |
| 4403 // is running a losing race against a horde of | |
| 4404 // mutators intent on flooding us with CMS updates | |
| 4405 // (dirty cards). | |
| 4406 // One, admittedly dumb, strategy is to give up | |
| 4407 // after a certain number of abortable precleaning loops | |
| 4408 // or after a certain maximum time. We want to make | |
| 4409 // this smarter in the next iteration. | |
| 4410 // XXX FIX ME!!! YSR | |
| 4411 size_t loops = 0, workdone = 0, cumworkdone = 0, waited = 0; | |
| 4412 while (!(should_abort_preclean() || | |
| 4413 ConcurrentMarkSweepThread::should_terminate())) { | |
| 4414 workdone = preclean_work(CMSPrecleanRefLists2, CMSPrecleanSurvivors2); | |
| 4415 cumworkdone += workdone; | |
| 4416 loops++; | |
| 4417 // Voluntarily terminate abortable preclean phase if we have | |
| 4418 // been at it for too long. | |
| 4419 if ((CMSMaxAbortablePrecleanLoops != 0) && | |
| 4420 loops >= CMSMaxAbortablePrecleanLoops) { | |
| 4421 if (PrintGCDetails) { | |
| 4422 gclog_or_tty->print(" CMS: abort preclean due to loops "); | |
| 4423 } | |
| 4424 break; | |
| 4425 } | |
| 4426 if (pa.wallclock_millis() > CMSMaxAbortablePrecleanTime) { | |
| 4427 if (PrintGCDetails) { | |
| 4428 gclog_or_tty->print(" CMS: abort preclean due to time "); | |
| 4429 } | |
| 4430 break; | |
| 4431 } | |
| 4432 // If we are doing little work each iteration, we should | |
| 4433 // take a short break. | |
| 4434 if (workdone < CMSAbortablePrecleanMinWorkPerIteration) { | |
| 4435 // Sleep for some time, waiting for work to accumulate | |
| 4436 stopTimer(); | |
| 4437 cmsThread()->wait_on_cms_lock(CMSAbortablePrecleanWaitMillis); | |
| 4438 startTimer(); | |
| 4439 waited++; | |
| 4440 } | |
| 4441 } | |
| 4442 if (PrintCMSStatistics > 0) { | |
| 4443 gclog_or_tty->print(" [%d iterations, %d waits, %d cards)] ", | |
| 4444 loops, waited, cumworkdone); | |
| 4445 } | |
| 4446 } | |
| 4447 CMSTokenSync x(true); // is cms thread | |
| 4448 if (_collectorState != Idling) { | |
| 4449 assert(_collectorState == AbortablePreclean, | |
| 4450 "Spontaneous state transition?"); | |
| 4451 _collectorState = FinalMarking; | |
| 4452 } // Else, a foreground collection completed this CMS cycle. | |
| 4453 return; | |
| 4454 } | |
| 4455 | |
| 4456 // Respond to an Eden sampling opportunity | |
| 4457 void CMSCollector::sample_eden() { | |
| 4458 // Make sure a young gc cannot sneak in between our | |
| 4459 // reading and recording of a sample. | |
| 4460 assert(Thread::current()->is_ConcurrentGC_thread(), | |
| 4461 "Only the cms thread may collect Eden samples"); | |
| 4462 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 4463 "Should collect samples while holding CMS token"); | |
| 4464 if (!_start_sampling) { | |
| 4465 return; | |
| 4466 } | |
| 4467 if (_eden_chunk_array) { | |
| 4468 if (_eden_chunk_index < _eden_chunk_capacity) { | |
| 4469 _eden_chunk_array[_eden_chunk_index] = *_top_addr; // take sample | |
| 4470 assert(_eden_chunk_array[_eden_chunk_index] <= *_end_addr, | |
| 4471 "Unexpected state of Eden"); | |
| 4472 // We'd like to check that what we just sampled is an oop-start address; | |
| 4473 // however, we cannot do that here since the object may not yet have been | |
| 4474 // initialized. So we'll instead do the check when we _use_ this sample | |
| 4475 // later. | |
| 4476 if (_eden_chunk_index == 0 || | |
| 4477 (pointer_delta(_eden_chunk_array[_eden_chunk_index], | |
| 4478 _eden_chunk_array[_eden_chunk_index-1]) | |
| 4479 >= CMSSamplingGrain)) { | |
| 4480 _eden_chunk_index++; // commit sample | |
| 4481 } | |
| 4482 } | |
| 4483 } | |
| 4484 if ((_collectorState == AbortablePreclean) && !_abort_preclean) { | |
| 4485 size_t used = get_eden_used(); | |
| 4486 size_t capacity = get_eden_capacity(); | |
| 4487 assert(used <= capacity, "Unexpected state of Eden"); | |
| 4488 if (used > (capacity/100 * CMSScheduleRemarkEdenPenetration)) { | |
| 4489 _abort_preclean = true; | |
| 4490 } | |
| 4491 } | |
| 4492 } | |
| 4493 | |
| 4494 | |
| 4495 size_t CMSCollector::preclean_work(bool clean_refs, bool clean_survivor) { | |
| 4496 assert(_collectorState == Precleaning || | |
| 4497 _collectorState == AbortablePreclean, "incorrect state"); | |
| 4498 ResourceMark rm; | |
| 4499 HandleMark hm; | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4500 |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4501 // Precleaning is currently not MT but the reference processor |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4502 // may be set for MT. Disable it temporarily here. |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4503 ReferenceProcessor* rp = ref_processor(); |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4504 ReferenceProcessorMTDiscoveryMutator rp_mut_discovery(rp, false); |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
4505 |
| 0 | 4506 // Do one pass of scrubbing the discovered reference lists |
| 4507 // to remove any reference objects with strongly-reachable | |
| 4508 // referents. | |
| 4509 if (clean_refs) { | |
| 4510 CMSPrecleanRefsYieldClosure yield_cl(this); | |
| 4511 assert(rp->span().equals(_span), "Spans should be equal"); | |
| 4512 CMSKeepAliveClosure keep_alive(this, _span, &_markBitMap, | |
| 935 | 4513 &_markStack, &_revisitStack, |
| 4514 true /* preclean */); | |
| 0 | 4515 CMSDrainMarkingStackClosure complete_trace(this, |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
4516 _span, &_markBitMap, &_markStack, |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
4517 &keep_alive, true /* preclean */); |
| 0 | 4518 |
| 4519 // We don't want this step to interfere with a young | |
| 4520 // collection because we don't want to take CPU | |
| 4521 // or memory bandwidth away from the young GC threads | |
| 4522 // (which may be as many as there are CPUs). | |
| 4523 // Note that we don't need to protect ourselves from | |
| 4524 // interference with mutators because they can't | |
| 4525 // manipulate the discovered reference lists nor affect | |
| 4526 // the computed reachability of the referents, the | |
| 4527 // only properties manipulated by the precleaning | |
| 4528 // of these reference lists. | |
| 4529 stopTimer(); | |
| 4530 CMSTokenSyncWithLocks x(true /* is cms thread */, | |
| 4531 bitMapLock()); | |
| 4532 startTimer(); | |
| 4533 sample_eden(); | |
| 935 | 4534 |
| 0 | 4535 // The following will yield to allow foreground |
| 4536 // collection to proceed promptly. XXX YSR: | |
| 4537 // The code in this method may need further | |
| 4538 // tweaking for better performance and some restructuring | |
| 4539 // for cleaner interfaces. | |
| 4540 rp->preclean_discovered_references( | |
| 4541 rp->is_alive_non_header(), &keep_alive, &complete_trace, | |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
4542 &yield_cl, should_unload_classes()); |
| 0 | 4543 } |
| 4544 | |
| 4545 if (clean_survivor) { // preclean the active survivor space(s) | |
| 4546 assert(_young_gen->kind() == Generation::DefNew || | |
| 4547 _young_gen->kind() == Generation::ParNew || | |
| 4548 _young_gen->kind() == Generation::ASParNew, | |
| 4549 "incorrect type for cast"); | |
| 4550 DefNewGeneration* dng = (DefNewGeneration*)_young_gen; | |
| 4551 PushAndMarkClosure pam_cl(this, _span, ref_processor(), | |
| 4552 &_markBitMap, &_modUnionTable, | |
| 4553 &_markStack, &_revisitStack, | |
| 4554 true /* precleaning phase */); | |
| 4555 stopTimer(); | |
| 4556 CMSTokenSyncWithLocks ts(true /* is cms thread */, | |
| 4557 bitMapLock()); | |
| 4558 startTimer(); | |
| 4559 unsigned int before_count = | |
| 4560 GenCollectedHeap::heap()->total_collections(); | |
| 4561 SurvivorSpacePrecleanClosure | |
| 4562 sss_cl(this, _span, &_markBitMap, &_markStack, | |
| 4563 &pam_cl, before_count, CMSYield); | |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
4564 DEBUG_ONLY(RememberKlassesChecker mx(should_unload_classes());) |
| 0 | 4565 dng->from()->object_iterate_careful(&sss_cl); |
| 4566 dng->to()->object_iterate_careful(&sss_cl); | |
| 4567 } | |
| 4568 MarkRefsIntoAndScanClosure | |
| 4569 mrias_cl(_span, ref_processor(), &_markBitMap, &_modUnionTable, | |
| 4570 &_markStack, &_revisitStack, this, CMSYield, | |
| 4571 true /* precleaning phase */); | |
| 4572 // CAUTION: The following closure has persistent state that may need to | |
| 4573 // be reset upon a decrease in the sequence of addresses it | |
| 4574 // processes. | |
| 4575 ScanMarkedObjectsAgainCarefullyClosure | |
| 4576 smoac_cl(this, _span, | |
| 4577 &_markBitMap, &_markStack, &_revisitStack, &mrias_cl, CMSYield); | |
| 4578 | |
| 4579 // Preclean dirty cards in ModUnionTable and CardTable using | |
| 4580 // appropriate convergence criterion; | |
| 4581 // repeat CMSPrecleanIter times unless we find that | |
| 4582 // we are losing. | |
| 4583 assert(CMSPrecleanIter < 10, "CMSPrecleanIter is too large"); | |
| 4584 assert(CMSPrecleanNumerator < CMSPrecleanDenominator, | |
| 4585 "Bad convergence multiplier"); | |
| 4586 assert(CMSPrecleanThreshold >= 100, | |
| 4587 "Unreasonably low CMSPrecleanThreshold"); | |
| 4588 | |
| 4589 size_t numIter, cumNumCards, lastNumCards, curNumCards; | |
| 4590 for (numIter = 0, cumNumCards = lastNumCards = curNumCards = 0; | |
| 4591 numIter < CMSPrecleanIter; | |
| 4592 numIter++, lastNumCards = curNumCards, cumNumCards += curNumCards) { | |
| 4593 curNumCards = preclean_mod_union_table(_cmsGen, &smoac_cl); | |
| 4594 if (CMSPermGenPrecleaningEnabled) { | |
| 4595 curNumCards += preclean_mod_union_table(_permGen, &smoac_cl); | |
| 4596 } | |
| 4597 if (Verbose && PrintGCDetails) { | |
| 4598 gclog_or_tty->print(" (modUnionTable: %d cards)", curNumCards); | |
| 4599 } | |
| 4600 // Either there are very few dirty cards, so re-mark | |
| 4601 // pause will be small anyway, or our pre-cleaning isn't | |
| 4602 // that much faster than the rate at which cards are being | |
| 4603 // dirtied, so we might as well stop and re-mark since | |
| 4604 // precleaning won't improve our re-mark time by much. | |
| 4605 if (curNumCards <= CMSPrecleanThreshold || | |
| 4606 (numIter > 0 && | |
| 4607 (curNumCards * CMSPrecleanDenominator > | |
| 4608 lastNumCards * CMSPrecleanNumerator))) { | |
| 4609 numIter++; | |
| 4610 cumNumCards += curNumCards; | |
| 4611 break; | |
| 4612 } | |
| 4613 } | |
| 4614 curNumCards = preclean_card_table(_cmsGen, &smoac_cl); | |
| 4615 if (CMSPermGenPrecleaningEnabled) { | |
| 4616 curNumCards += preclean_card_table(_permGen, &smoac_cl); | |
| 4617 } | |
| 4618 cumNumCards += curNumCards; | |
| 4619 if (PrintGCDetails && PrintCMSStatistics != 0) { | |
| 4620 gclog_or_tty->print_cr(" (cardTable: %d cards, re-scanned %d cards, %d iterations)", | |
| 4621 curNumCards, cumNumCards, numIter); | |
| 4622 } | |
| 4623 return cumNumCards; // as a measure of useful work done | |
| 4624 } | |
| 4625 | |
| 4626 // PRECLEANING NOTES: | |
| 4627 // Precleaning involves: | |
| 4628 // . reading the bits of the modUnionTable and clearing the set bits. | |
| 4629 // . For the cards corresponding to the set bits, we scan the | |
| 4630 // objects on those cards. This means we need the free_list_lock | |
| 4631 // so that we can safely iterate over the CMS space when scanning | |
| 4632 // for oops. | |
| 4633 // . When we scan the objects, we'll be both reading and setting | |
| 4634 // marks in the marking bit map, so we'll need the marking bit map. | |
| 4635 // . For protecting _collector_state transitions, we take the CGC_lock. | |
| 4636 // Note that any races in the reading of of card table entries by the | |
| 4637 // CMS thread on the one hand and the clearing of those entries by the | |
| 4638 // VM thread or the setting of those entries by the mutator threads on the | |
| 4639 // other are quite benign. However, for efficiency it makes sense to keep | |
| 4640 // the VM thread from racing with the CMS thread while the latter is | |
| 4641 // dirty card info to the modUnionTable. We therefore also use the | |
| 4642 // CGC_lock to protect the reading of the card table and the mod union | |
| 4643 // table by the CM thread. | |
| 4644 // . We run concurrently with mutator updates, so scanning | |
| 4645 // needs to be done carefully -- we should not try to scan | |
| 4646 // potentially uninitialized objects. | |
| 4647 // | |
| 4648 // Locking strategy: While holding the CGC_lock, we scan over and | |
| 4649 // reset a maximal dirty range of the mod union / card tables, then lock | |
| 4650 // the free_list_lock and bitmap lock to do a full marking, then | |
| 4651 // release these locks; and repeat the cycle. This allows for a | |
| 4652 // certain amount of fairness in the sharing of these locks between | |
| 4653 // the CMS collector on the one hand, and the VM thread and the | |
| 4654 // mutators on the other. | |
| 4655 | |
| 4656 // NOTE: preclean_mod_union_table() and preclean_card_table() | |
| 4657 // further below are largely identical; if you need to modify | |
| 4658 // one of these methods, please check the other method too. | |
| 4659 | |
| 4660 size_t CMSCollector::preclean_mod_union_table( | |
| 4661 ConcurrentMarkSweepGeneration* gen, | |
| 4662 ScanMarkedObjectsAgainCarefullyClosure* cl) { | |
| 4663 verify_work_stacks_empty(); | |
| 4664 verify_overflow_empty(); | |
| 4665 | |
| 935 | 4666 // Turn off checking for this method but turn it back on |
| 4667 // selectively. There are yield points in this method | |
| 4668 // but it is difficult to turn the checking off just around | |
| 4669 // the yield points. It is simpler to selectively turn | |
| 4670 // it on. | |
| 4671 DEBUG_ONLY(RememberKlassesChecker mux(false);) | |
| 4672 | |
| 0 | 4673 // strategy: starting with the first card, accumulate contiguous |
| 4674 // ranges of dirty cards; clear these cards, then scan the region | |
| 4675 // covered by these cards. | |
| 4676 | |
| 4677 // Since all of the MUT is committed ahead, we can just use | |
| 4678 // that, in case the generations expand while we are precleaning. | |
| 4679 // It might also be fine to just use the committed part of the | |
| 4680 // generation, but we might potentially miss cards when the | |
| 4681 // generation is rapidly expanding while we are in the midst | |
| 4682 // of precleaning. | |
| 4683 HeapWord* startAddr = gen->reserved().start(); | |
| 4684 HeapWord* endAddr = gen->reserved().end(); | |
| 4685 | |
| 4686 cl->setFreelistLock(gen->freelistLock()); // needed for yielding | |
| 4687 | |
| 4688 size_t numDirtyCards, cumNumDirtyCards; | |
| 4689 HeapWord *nextAddr, *lastAddr; | |
| 4690 for (cumNumDirtyCards = numDirtyCards = 0, | |
| 4691 nextAddr = lastAddr = startAddr; | |
| 4692 nextAddr < endAddr; | |
| 4693 nextAddr = lastAddr, cumNumDirtyCards += numDirtyCards) { | |
| 4694 | |
| 4695 ResourceMark rm; | |
| 4696 HandleMark hm; | |
| 4697 | |
| 4698 MemRegion dirtyRegion; | |
| 4699 { | |
| 4700 stopTimer(); | |
| 935 | 4701 // Potential yield point |
| 0 | 4702 CMSTokenSync ts(true); |
| 4703 startTimer(); | |
| 4704 sample_eden(); | |
| 4705 // Get dirty region starting at nextOffset (inclusive), | |
| 4706 // simultaneously clearing it. | |
| 4707 dirtyRegion = | |
| 4708 _modUnionTable.getAndClearMarkedRegion(nextAddr, endAddr); | |
| 4709 assert(dirtyRegion.start() >= nextAddr, | |
| 4710 "returned region inconsistent?"); | |
| 4711 } | |
| 4712 // Remember where the next search should begin. | |
| 4713 // The returned region (if non-empty) is a right open interval, | |
| 4714 // so lastOffset is obtained from the right end of that | |
| 4715 // interval. | |
| 4716 lastAddr = dirtyRegion.end(); | |
| 4717 // Should do something more transparent and less hacky XXX | |
| 4718 numDirtyCards = | |
| 4719 _modUnionTable.heapWordDiffToOffsetDiff(dirtyRegion.word_size()); | |
| 4720 | |
| 4721 // We'll scan the cards in the dirty region (with periodic | |
| 4722 // yields for foreground GC as needed). | |
| 4723 if (!dirtyRegion.is_empty()) { | |
| 4724 assert(numDirtyCards > 0, "consistency check"); | |
| 4725 HeapWord* stop_point = NULL; | |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
4726 stopTimer(); |
| 935 | 4727 // Potential yield point |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
4728 CMSTokenSyncWithLocks ts(true, gen->freelistLock(), |
|
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
4729 bitMapLock()); |
|
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
4730 startTimer(); |
| 0 | 4731 { |
| 4732 verify_work_stacks_empty(); | |
| 4733 verify_overflow_empty(); | |
| 4734 sample_eden(); | |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
4735 DEBUG_ONLY(RememberKlassesChecker mx(should_unload_classes());) |
| 0 | 4736 stop_point = |
| 4737 gen->cmsSpace()->object_iterate_careful_m(dirtyRegion, cl); | |
| 4738 } | |
| 4739 if (stop_point != NULL) { | |
| 4740 // The careful iteration stopped early either because it found an | |
| 4741 // uninitialized object, or because we were in the midst of an | |
| 4742 // "abortable preclean", which should now be aborted. Redirty | |
| 4743 // the bits corresponding to the partially-scanned or unscanned | |
| 4744 // cards. We'll either restart at the next block boundary or | |
| 4745 // abort the preclean. | |
| 4746 assert((CMSPermGenPrecleaningEnabled && (gen == _permGen)) || | |
| 4747 (_collectorState == AbortablePreclean && should_abort_preclean()), | |
| 4748 "Unparsable objects should only be in perm gen."); | |
| 4749 _modUnionTable.mark_range(MemRegion(stop_point, dirtyRegion.end())); | |
| 4750 if (should_abort_preclean()) { | |
| 4751 break; // out of preclean loop | |
| 4752 } else { | |
| 4753 // Compute the next address at which preclean should pick up; | |
| 4754 // might need bitMapLock in order to read P-bits. | |
| 4755 lastAddr = next_card_start_after_block(stop_point); | |
| 4756 } | |
| 4757 } | |
| 4758 } else { | |
| 4759 assert(lastAddr == endAddr, "consistency check"); | |
| 4760 assert(numDirtyCards == 0, "consistency check"); | |
| 4761 break; | |
| 4762 } | |
| 4763 } | |
| 4764 verify_work_stacks_empty(); | |
| 4765 verify_overflow_empty(); | |
| 4766 return cumNumDirtyCards; | |
| 4767 } | |
| 4768 | |
| 4769 // NOTE: preclean_mod_union_table() above and preclean_card_table() | |
| 4770 // below are largely identical; if you need to modify | |
| 4771 // one of these methods, please check the other method too. | |
| 4772 | |
| 4773 size_t CMSCollector::preclean_card_table(ConcurrentMarkSweepGeneration* gen, | |
| 4774 ScanMarkedObjectsAgainCarefullyClosure* cl) { | |
| 4775 // strategy: it's similar to precleamModUnionTable above, in that | |
| 4776 // we accumulate contiguous ranges of dirty cards, mark these cards | |
| 4777 // precleaned, then scan the region covered by these cards. | |
| 4778 HeapWord* endAddr = (HeapWord*)(gen->_virtual_space.high()); | |
| 4779 HeapWord* startAddr = (HeapWord*)(gen->_virtual_space.low()); | |
| 4780 | |
| 4781 cl->setFreelistLock(gen->freelistLock()); // needed for yielding | |
| 4782 | |
| 4783 size_t numDirtyCards, cumNumDirtyCards; | |
| 4784 HeapWord *lastAddr, *nextAddr; | |
| 4785 | |
| 4786 for (cumNumDirtyCards = numDirtyCards = 0, | |
| 4787 nextAddr = lastAddr = startAddr; | |
| 4788 nextAddr < endAddr; | |
| 4789 nextAddr = lastAddr, cumNumDirtyCards += numDirtyCards) { | |
| 4790 | |
| 4791 ResourceMark rm; | |
| 4792 HandleMark hm; | |
| 4793 | |
| 4794 MemRegion dirtyRegion; | |
| 4795 { | |
| 4796 // See comments in "Precleaning notes" above on why we | |
| 4797 // do this locking. XXX Could the locking overheads be | |
| 4798 // too high when dirty cards are sparse? [I don't think so.] | |
| 4799 stopTimer(); | |
| 4800 CMSTokenSync x(true); // is cms thread | |
| 4801 startTimer(); | |
| 4802 sample_eden(); | |
| 4803 // Get and clear dirty region from card table | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
4804 dirtyRegion = _ct->ct_bs()->dirty_card_range_after_reset( |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
4805 MemRegion(nextAddr, endAddr), |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
4806 true, |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
4807 CardTableModRefBS::precleaned_card_val()); |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
4808 |
| 0 | 4809 assert(dirtyRegion.start() >= nextAddr, |
| 4810 "returned region inconsistent?"); | |
| 4811 } | |
| 4812 lastAddr = dirtyRegion.end(); | |
| 4813 numDirtyCards = | |
| 4814 dirtyRegion.word_size()/CardTableModRefBS::card_size_in_words; | |
| 4815 | |
| 4816 if (!dirtyRegion.is_empty()) { | |
| 4817 stopTimer(); | |
| 4818 CMSTokenSyncWithLocks ts(true, gen->freelistLock(), bitMapLock()); | |
| 4819 startTimer(); | |
| 4820 sample_eden(); | |
| 4821 verify_work_stacks_empty(); | |
| 4822 verify_overflow_empty(); | |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
4823 DEBUG_ONLY(RememberKlassesChecker mx(should_unload_classes());) |
| 0 | 4824 HeapWord* stop_point = |
| 4825 gen->cmsSpace()->object_iterate_careful_m(dirtyRegion, cl); | |
| 4826 if (stop_point != NULL) { | |
| 4827 // The careful iteration stopped early because it found an | |
| 4828 // uninitialized object. Redirty the bits corresponding to the | |
| 4829 // partially-scanned or unscanned cards, and start again at the | |
| 4830 // next block boundary. | |
| 4831 assert(CMSPermGenPrecleaningEnabled || | |
| 4832 (_collectorState == AbortablePreclean && should_abort_preclean()), | |
| 4833 "Unparsable objects should only be in perm gen."); | |
| 4834 _ct->ct_bs()->invalidate(MemRegion(stop_point, dirtyRegion.end())); | |
| 4835 if (should_abort_preclean()) { | |
| 4836 break; // out of preclean loop | |
| 4837 } else { | |
| 4838 // Compute the next address at which preclean should pick up. | |
| 4839 lastAddr = next_card_start_after_block(stop_point); | |
| 4840 } | |
| 4841 } | |
| 4842 } else { | |
| 4843 break; | |
| 4844 } | |
| 4845 } | |
| 4846 verify_work_stacks_empty(); | |
| 4847 verify_overflow_empty(); | |
| 4848 return cumNumDirtyCards; | |
| 4849 } | |
| 4850 | |
| 4851 void CMSCollector::checkpointRootsFinal(bool asynch, | |
| 4852 bool clear_all_soft_refs, bool init_mark_was_synchronous) { | |
| 4853 assert(_collectorState == FinalMarking, "incorrect state transition?"); | |
| 4854 check_correct_thread_executing(); | |
| 4855 // world is stopped at this checkpoint | |
| 4856 assert(SafepointSynchronize::is_at_safepoint(), | |
| 4857 "world should be stopped"); | |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
4858 TraceCMSMemoryManagerStats tms(_collectorState,GenCollectedHeap::heap()->gc_cause()); |
|
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
4859 |
| 0 | 4860 verify_work_stacks_empty(); |
| 4861 verify_overflow_empty(); | |
| 4862 | |
| 4863 SpecializationStats::clear(); | |
| 4864 if (PrintGCDetails) { | |
| 4865 gclog_or_tty->print("[YG occupancy: "SIZE_FORMAT" K ("SIZE_FORMAT" K)]", | |
| 4866 _young_gen->used() / K, | |
| 4867 _young_gen->capacity() / K); | |
| 4868 } | |
| 4869 if (asynch) { | |
| 4870 if (CMSScavengeBeforeRemark) { | |
| 4871 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 4872 // Temporarily set flag to false, GCH->do_collection will | |
| 4873 // expect it to be false and set to true | |
| 4874 FlagSetting fl(gch->_is_gc_active, false); | |
| 4875 NOT_PRODUCT(TraceTime t("Scavenge-Before-Remark", | |
| 4876 PrintGCDetails && Verbose, true, gclog_or_tty);) | |
| 4877 int level = _cmsGen->level() - 1; | |
| 4878 if (level >= 0) { | |
| 4879 gch->do_collection(true, // full (i.e. force, see below) | |
| 4880 false, // !clear_all_soft_refs | |
| 4881 0, // size | |
| 4882 false, // is_tlab | |
| 4883 level // max_level | |
| 4884 ); | |
| 4885 } | |
| 4886 } | |
| 4887 FreelistLocker x(this); | |
| 4888 MutexLockerEx y(bitMapLock(), | |
| 4889 Mutex::_no_safepoint_check_flag); | |
| 4890 assert(!init_mark_was_synchronous, "but that's impossible!"); | |
| 4891 checkpointRootsFinalWork(asynch, clear_all_soft_refs, false); | |
| 4892 } else { | |
| 4893 // already have all the locks | |
| 4894 checkpointRootsFinalWork(asynch, clear_all_soft_refs, | |
| 4895 init_mark_was_synchronous); | |
| 4896 } | |
| 4897 verify_work_stacks_empty(); | |
| 4898 verify_overflow_empty(); | |
| 4899 SpecializationStats::print(); | |
| 4900 } | |
| 4901 | |
| 4902 void CMSCollector::checkpointRootsFinalWork(bool asynch, | |
| 4903 bool clear_all_soft_refs, bool init_mark_was_synchronous) { | |
| 4904 | |
| 4905 NOT_PRODUCT(TraceTime tr("checkpointRootsFinalWork", PrintGCDetails, false, gclog_or_tty);) | |
| 4906 | |
| 4907 assert(haveFreelistLocks(), "must have free list locks"); | |
| 4908 assert_lock_strong(bitMapLock()); | |
| 4909 | |
| 4910 if (UseAdaptiveSizePolicy) { | |
| 4911 size_policy()->checkpoint_roots_final_begin(); | |
| 4912 } | |
| 4913 | |
| 4914 ResourceMark rm; | |
| 4915 HandleMark hm; | |
| 4916 | |
| 4917 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 4918 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
4919 if (should_unload_classes()) { |
| 0 | 4920 CodeCache::gc_prologue(); |
| 4921 } | |
| 4922 assert(haveFreelistLocks(), "must have free list locks"); | |
| 4923 assert_lock_strong(bitMapLock()); | |
| 4924 | |
|
1190
4788266644c1
6895236: CMS: cmsOopClosures.inline.hpp:43 assert(..., "Should remember klasses in this context")
jmasa
parents:
1145
diff
changeset
|
4925 DEBUG_ONLY(RememberKlassesChecker fmx(should_unload_classes());) |
| 0 | 4926 if (!init_mark_was_synchronous) { |
| 4927 // We might assume that we need not fill TLAB's when | |
| 4928 // CMSScavengeBeforeRemark is set, because we may have just done | |
| 4929 // a scavenge which would have filled all TLAB's -- and besides | |
| 4930 // Eden would be empty. This however may not always be the case -- | |
| 4931 // for instance although we asked for a scavenge, it may not have | |
| 4932 // happened because of a JNI critical section. We probably need | |
| 4933 // a policy for deciding whether we can in that case wait until | |
| 4934 // the critical section releases and then do the remark following | |
| 4935 // the scavenge, and skip it here. In the absence of that policy, | |
| 4936 // or of an indication of whether the scavenge did indeed occur, | |
| 4937 // we cannot rely on TLAB's having been filled and must do | |
| 4938 // so here just in case a scavenge did not happen. | |
| 4939 gch->ensure_parsability(false); // fill TLAB's, but no need to retire them | |
| 4940 // Update the saved marks which may affect the root scans. | |
| 4941 gch->save_marks(); | |
| 4942 | |
| 4943 { | |
| 4944 COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact;) | |
| 4945 | |
| 4946 // Note on the role of the mod union table: | |
| 4947 // Since the marker in "markFromRoots" marks concurrently with | |
| 4948 // mutators, it is possible for some reachable objects not to have been | |
| 4949 // scanned. For instance, an only reference to an object A was | |
| 4950 // placed in object B after the marker scanned B. Unless B is rescanned, | |
| 4951 // A would be collected. Such updates to references in marked objects | |
| 4952 // are detected via the mod union table which is the set of all cards | |
| 4953 // dirtied since the first checkpoint in this GC cycle and prior to | |
| 4954 // the most recent young generation GC, minus those cleaned up by the | |
| 4955 // concurrent precleaning. | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
4956 if (CMSParallelRemarkEnabled && CollectedHeap::use_parallel_gc_threads()) { |
| 0 | 4957 TraceTime t("Rescan (parallel) ", PrintGCDetails, false, gclog_or_tty); |
| 4958 do_remark_parallel(); | |
| 4959 } else { | |
| 4960 TraceTime t("Rescan (non-parallel) ", PrintGCDetails, false, | |
| 4961 gclog_or_tty); | |
| 4962 do_remark_non_parallel(); | |
| 4963 } | |
| 4964 } | |
| 4965 } else { | |
| 4966 assert(!asynch, "Can't have init_mark_was_synchronous in asynch mode"); | |
| 4967 // The initial mark was stop-world, so there's no rescanning to | |
| 4968 // do; go straight on to the next step below. | |
| 4969 } | |
| 4970 verify_work_stacks_empty(); | |
| 4971 verify_overflow_empty(); | |
| 4972 | |
| 4973 { | |
| 4974 NOT_PRODUCT(TraceTime ts("refProcessingWork", PrintGCDetails, false, gclog_or_tty);) | |
| 4975 refProcessingWork(asynch, clear_all_soft_refs); | |
| 4976 } | |
| 4977 verify_work_stacks_empty(); | |
| 4978 verify_overflow_empty(); | |
| 4979 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
4980 if (should_unload_classes()) { |
| 0 | 4981 CodeCache::gc_epilogue(); |
| 4982 } | |
|
2147
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2137
diff
changeset
|
4983 JvmtiExport::gc_epilogue(); |
| 0 | 4984 |
| 4985 // If we encountered any (marking stack / work queue) overflow | |
| 4986 // events during the current CMS cycle, take appropriate | |
| 4987 // remedial measures, where possible, so as to try and avoid | |
| 4988 // recurrence of that condition. | |
| 4989 assert(_markStack.isEmpty(), "No grey objects"); | |
| 4990 size_t ser_ovflw = _ser_pmc_remark_ovflw + _ser_pmc_preclean_ovflw + | |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
4991 _ser_kac_ovflw + _ser_kac_preclean_ovflw; |
| 0 | 4992 if (ser_ovflw > 0) { |
| 4993 if (PrintCMSStatistics != 0) { | |
| 4994 gclog_or_tty->print_cr("Marking stack overflow (benign) " | |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
4995 "(pmc_pc="SIZE_FORMAT", pmc_rm="SIZE_FORMAT", kac="SIZE_FORMAT |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
4996 ", kac_preclean="SIZE_FORMAT")", |
| 0 | 4997 _ser_pmc_preclean_ovflw, _ser_pmc_remark_ovflw, |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
4998 _ser_kac_ovflw, _ser_kac_preclean_ovflw); |
| 0 | 4999 } |
| 5000 _markStack.expand(); | |
| 5001 _ser_pmc_remark_ovflw = 0; | |
| 5002 _ser_pmc_preclean_ovflw = 0; | |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
5003 _ser_kac_preclean_ovflw = 0; |
| 0 | 5004 _ser_kac_ovflw = 0; |
| 5005 } | |
| 5006 if (_par_pmc_remark_ovflw > 0 || _par_kac_ovflw > 0) { | |
| 5007 if (PrintCMSStatistics != 0) { | |
| 5008 gclog_or_tty->print_cr("Work queue overflow (benign) " | |
| 5009 "(pmc_rm="SIZE_FORMAT", kac="SIZE_FORMAT")", | |
| 5010 _par_pmc_remark_ovflw, _par_kac_ovflw); | |
| 5011 } | |
| 5012 _par_pmc_remark_ovflw = 0; | |
| 5013 _par_kac_ovflw = 0; | |
| 5014 } | |
| 5015 if (PrintCMSStatistics != 0) { | |
| 5016 if (_markStack._hit_limit > 0) { | |
| 5017 gclog_or_tty->print_cr(" (benign) Hit max stack size limit ("SIZE_FORMAT")", | |
| 5018 _markStack._hit_limit); | |
| 5019 } | |
| 5020 if (_markStack._failed_double > 0) { | |
| 5021 gclog_or_tty->print_cr(" (benign) Failed stack doubling ("SIZE_FORMAT")," | |
| 5022 " current capacity "SIZE_FORMAT, | |
| 5023 _markStack._failed_double, | |
| 5024 _markStack.capacity()); | |
| 5025 } | |
| 5026 } | |
| 5027 _markStack._hit_limit = 0; | |
| 5028 _markStack._failed_double = 0; | |
| 5029 | |
| 935 | 5030 // Check that all the klasses have been checked |
| 5031 assert(_revisitStack.isEmpty(), "Not all klasses revisited"); | |
| 5032 | |
| 0 | 5033 if ((VerifyAfterGC || VerifyDuringGC) && |
| 5034 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 5035 verify_after_remark(); | |
| 5036 } | |
| 5037 | |
| 5038 // Change under the freelistLocks. | |
| 5039 _collectorState = Sweeping; | |
| 5040 // Call isAllClear() under bitMapLock | |
| 5041 assert(_modUnionTable.isAllClear(), "Should be clear by end of the" | |
| 5042 " final marking"); | |
| 5043 if (UseAdaptiveSizePolicy) { | |
| 5044 size_policy()->checkpoint_roots_final_end(gch->gc_cause()); | |
| 5045 } | |
| 5046 } | |
| 5047 | |
| 5048 // Parallel remark task | |
| 5049 class CMSParRemarkTask: public AbstractGangTask { | |
| 5050 CMSCollector* _collector; | |
| 5051 int _n_workers; | |
| 5052 CompactibleFreeListSpace* _cms_space; | |
| 5053 CompactibleFreeListSpace* _perm_space; | |
| 5054 | |
| 5055 // The per-thread work queues, available here for stealing. | |
| 5056 OopTaskQueueSet* _task_queues; | |
| 5057 ParallelTaskTerminator _term; | |
| 5058 | |
| 5059 public: | |
|
4095
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5060 // A value of 0 passed to n_workers will cause the number of |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5061 // workers to be taken from the active workers in the work gang. |
| 0 | 5062 CMSParRemarkTask(CMSCollector* collector, |
| 5063 CompactibleFreeListSpace* cms_space, | |
| 5064 CompactibleFreeListSpace* perm_space, | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5065 int n_workers, FlexibleWorkGang* workers, |
| 0 | 5066 OopTaskQueueSet* task_queues): |
| 5067 AbstractGangTask("Rescan roots and grey objects in parallel"), | |
| 5068 _collector(collector), | |
| 5069 _cms_space(cms_space), _perm_space(perm_space), | |
| 5070 _n_workers(n_workers), | |
| 5071 _task_queues(task_queues), | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5072 _term(n_workers, task_queues) { } |
| 0 | 5073 |
| 5074 OopTaskQueueSet* task_queues() { return _task_queues; } | |
| 5075 | |
| 5076 OopTaskQueue* work_queue(int i) { return task_queues()->queue(i); } | |
| 5077 | |
| 5078 ParallelTaskTerminator* terminator() { return &_term; } | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5079 int n_workers() { return _n_workers; } |
| 0 | 5080 |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5081 void work(uint worker_id); |
| 0 | 5082 |
| 5083 private: | |
| 5084 // Work method in support of parallel rescan ... of young gen spaces | |
| 5085 void do_young_space_rescan(int i, Par_MarkRefsIntoAndScanClosure* cl, | |
| 5086 ContiguousSpace* space, | |
| 5087 HeapWord** chunk_array, size_t chunk_top); | |
| 5088 | |
| 5089 // ... of dirty cards in old space | |
| 5090 void do_dirty_card_rescan_tasks(CompactibleFreeListSpace* sp, int i, | |
| 5091 Par_MarkRefsIntoAndScanClosure* cl); | |
| 5092 | |
| 5093 // ... work stealing for the above | |
| 5094 void do_work_steal(int i, Par_MarkRefsIntoAndScanClosure* cl, int* seed); | |
| 5095 }; | |
| 5096 | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5097 // work_queue(i) is passed to the closure |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5098 // Par_MarkRefsIntoAndScanClosure. The "i" parameter |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5099 // also is passed to do_dirty_card_rescan_tasks() and to |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5100 // do_work_steal() to select the i-th task_queue. |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5101 |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5102 void CMSParRemarkTask::work(uint worker_id) { |
| 0 | 5103 elapsedTimer _timer; |
| 5104 ResourceMark rm; | |
| 5105 HandleMark hm; | |
| 5106 | |
| 5107 // ---------- rescan from roots -------------- | |
| 5108 _timer.start(); | |
| 5109 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 5110 Par_MarkRefsIntoAndScanClosure par_mrias_cl(_collector, | |
| 5111 _collector->_span, _collector->ref_processor(), | |
| 5112 &(_collector->_markBitMap), | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5113 work_queue(worker_id), &(_collector->_revisitStack)); |
| 0 | 5114 |
| 5115 // Rescan young gen roots first since these are likely | |
| 5116 // coarsely partitioned and may, on that account, constitute | |
| 5117 // the critical path; thus, it's best to start off that | |
| 5118 // work first. | |
| 5119 // ---------- young gen roots -------------- | |
| 5120 { | |
| 5121 DefNewGeneration* dng = _collector->_young_gen->as_DefNewGeneration(); | |
| 5122 EdenSpace* eden_space = dng->eden(); | |
| 5123 ContiguousSpace* from_space = dng->from(); | |
| 5124 ContiguousSpace* to_space = dng->to(); | |
| 5125 | |
| 5126 HeapWord** eca = _collector->_eden_chunk_array; | |
| 5127 size_t ect = _collector->_eden_chunk_index; | |
| 5128 HeapWord** sca = _collector->_survivor_chunk_array; | |
| 5129 size_t sct = _collector->_survivor_chunk_index; | |
| 5130 | |
| 5131 assert(ect <= _collector->_eden_chunk_capacity, "out of bounds"); | |
| 5132 assert(sct <= _collector->_survivor_chunk_capacity, "out of bounds"); | |
| 5133 | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5134 do_young_space_rescan(worker_id, &par_mrias_cl, to_space, NULL, 0); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5135 do_young_space_rescan(worker_id, &par_mrias_cl, from_space, sca, sct); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5136 do_young_space_rescan(worker_id, &par_mrias_cl, eden_space, eca, ect); |
| 0 | 5137 |
| 5138 _timer.stop(); | |
| 5139 if (PrintCMSStatistics != 0) { | |
| 5140 gclog_or_tty->print_cr( | |
| 5141 "Finished young gen rescan work in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5142 worker_id, _timer.seconds()); |
| 0 | 5143 } |
| 5144 } | |
| 5145 | |
| 5146 // ---------- remaining roots -------------- | |
| 5147 _timer.reset(); | |
| 5148 _timer.start(); | |
| 5149 gch->gen_process_strong_roots(_collector->_cmsGen->level(), | |
| 5150 false, // yg was scanned above | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5151 false, // this is parallel code |
| 0 | 5152 true, // collecting perm gen |
| 5153 SharedHeap::ScanningOption(_collector->CMSCollector::roots_scanning_options()), | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5154 &par_mrias_cl, |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5155 true, // walk all of code cache if (so & SO_CodeCache) |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5156 NULL); |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5157 assert(_collector->should_unload_classes() |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5158 || (_collector->CMSCollector::roots_scanning_options() & SharedHeap::SO_CodeCache), |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5159 "if we didn't scan the code cache, we have to be ready to drop nmethods with expired weak oops"); |
| 0 | 5160 _timer.stop(); |
| 5161 if (PrintCMSStatistics != 0) { | |
| 5162 gclog_or_tty->print_cr( | |
| 5163 "Finished remaining root rescan work in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5164 worker_id, _timer.seconds()); |
| 0 | 5165 } |
| 5166 | |
| 5167 // ---------- rescan dirty cards ------------ | |
| 5168 _timer.reset(); | |
| 5169 _timer.start(); | |
| 5170 | |
| 5171 // Do the rescan tasks for each of the two spaces | |
| 5172 // (cms_space and perm_space) in turn. | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5173 // "worker_id" is passed to select the task_queue for "worker_id" |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5174 do_dirty_card_rescan_tasks(_cms_space, worker_id, &par_mrias_cl); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5175 do_dirty_card_rescan_tasks(_perm_space, worker_id, &par_mrias_cl); |
| 0 | 5176 _timer.stop(); |
| 5177 if (PrintCMSStatistics != 0) { | |
| 5178 gclog_or_tty->print_cr( | |
| 5179 "Finished dirty card rescan work in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5180 worker_id, _timer.seconds()); |
| 0 | 5181 } |
| 5182 | |
| 5183 // ---------- steal work from other threads ... | |
| 5184 // ---------- ... and drain overflow list. | |
| 5185 _timer.reset(); | |
| 5186 _timer.start(); | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5187 do_work_steal(worker_id, &par_mrias_cl, _collector->hash_seed(worker_id)); |
| 0 | 5188 _timer.stop(); |
| 5189 if (PrintCMSStatistics != 0) { | |
| 5190 gclog_or_tty->print_cr( | |
| 5191 "Finished work stealing in %dth thread: %3.3f sec", | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5192 worker_id, _timer.seconds()); |
| 0 | 5193 } |
| 5194 } | |
| 5195 | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5196 // Note that parameter "i" is not used. |
| 0 | 5197 void |
| 5198 CMSParRemarkTask::do_young_space_rescan(int i, | |
| 5199 Par_MarkRefsIntoAndScanClosure* cl, ContiguousSpace* space, | |
| 5200 HeapWord** chunk_array, size_t chunk_top) { | |
| 5201 // Until all tasks completed: | |
| 5202 // . claim an unclaimed task | |
| 5203 // . compute region boundaries corresponding to task claimed | |
| 5204 // using chunk_array | |
| 5205 // . par_oop_iterate(cl) over that region | |
| 5206 | |
| 5207 ResourceMark rm; | |
| 5208 HandleMark hm; | |
| 5209 | |
| 5210 SequentialSubTasksDone* pst = space->par_seq_tasks(); | |
| 5211 assert(pst->valid(), "Uninitialized use?"); | |
| 5212 | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5213 uint nth_task = 0; |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5214 uint n_tasks = pst->n_tasks(); |
| 0 | 5215 |
| 5216 HeapWord *start, *end; | |
| 5217 while (!pst->is_task_claimed(/* reference */ nth_task)) { | |
| 5218 // We claimed task # nth_task; compute its boundaries. | |
| 5219 if (chunk_top == 0) { // no samples were taken | |
| 5220 assert(nth_task == 0 && n_tasks == 1, "Can have only 1 EdenSpace task"); | |
| 5221 start = space->bottom(); | |
| 5222 end = space->top(); | |
| 5223 } else if (nth_task == 0) { | |
| 5224 start = space->bottom(); | |
| 5225 end = chunk_array[nth_task]; | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5226 } else if (nth_task < (uint)chunk_top) { |
| 0 | 5227 assert(nth_task >= 1, "Control point invariant"); |
| 5228 start = chunk_array[nth_task - 1]; | |
| 5229 end = chunk_array[nth_task]; | |
| 5230 } else { | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5231 assert(nth_task == (uint)chunk_top, "Control point invariant"); |
| 0 | 5232 start = chunk_array[chunk_top - 1]; |
| 5233 end = space->top(); | |
| 5234 } | |
| 5235 MemRegion mr(start, end); | |
| 5236 // Verify that mr is in space | |
| 5237 assert(mr.is_empty() || space->used_region().contains(mr), | |
| 5238 "Should be in space"); | |
| 5239 // Verify that "start" is an object boundary | |
| 5240 assert(mr.is_empty() || oop(mr.start())->is_oop(), | |
| 5241 "Should be an oop"); | |
| 5242 space->par_oop_iterate(mr, cl); | |
| 5243 } | |
| 5244 pst->all_tasks_completed(); | |
| 5245 } | |
| 5246 | |
| 5247 void | |
| 5248 CMSParRemarkTask::do_dirty_card_rescan_tasks( | |
| 5249 CompactibleFreeListSpace* sp, int i, | |
| 5250 Par_MarkRefsIntoAndScanClosure* cl) { | |
| 5251 // Until all tasks completed: | |
| 5252 // . claim an unclaimed task | |
| 5253 // . compute region boundaries corresponding to task claimed | |
| 5254 // . transfer dirty bits ct->mut for that region | |
| 5255 // . apply rescanclosure to dirty mut bits for that region | |
| 5256 | |
| 5257 ResourceMark rm; | |
| 5258 HandleMark hm; | |
| 5259 | |
| 5260 OopTaskQueue* work_q = work_queue(i); | |
| 5261 ModUnionClosure modUnionClosure(&(_collector->_modUnionTable)); | |
| 5262 // CAUTION! CAUTION! CAUTION! CAUTION! CAUTION! CAUTION! CAUTION! | |
| 5263 // CAUTION: This closure has state that persists across calls to | |
| 5264 // the work method dirty_range_iterate_clear() in that it has | |
| 5265 // imbedded in it a (subtype of) UpwardsObjectClosure. The | |
| 5266 // use of that state in the imbedded UpwardsObjectClosure instance | |
| 5267 // assumes that the cards are always iterated (even if in parallel | |
| 5268 // by several threads) in monotonically increasing order per each | |
| 5269 // thread. This is true of the implementation below which picks | |
| 5270 // card ranges (chunks) in monotonically increasing order globally | |
| 5271 // and, a-fortiori, in monotonically increasing order per thread | |
| 5272 // (the latter order being a subsequence of the former). | |
| 5273 // If the work code below is ever reorganized into a more chaotic | |
| 5274 // work-partitioning form than the current "sequential tasks" | |
| 5275 // paradigm, the use of that persistent state will have to be | |
| 5276 // revisited and modified appropriately. See also related | |
| 5277 // bug 4756801 work on which should examine this code to make | |
| 5278 // sure that the changes there do not run counter to the | |
| 5279 // assumptions made here and necessary for correctness and | |
| 5280 // efficiency. Note also that this code might yield inefficient | |
| 5281 // behaviour in the case of very large objects that span one or | |
| 5282 // more work chunks. Such objects would potentially be scanned | |
| 5283 // several times redundantly. Work on 4756801 should try and | |
| 5284 // address that performance anomaly if at all possible. XXX | |
| 5285 MemRegion full_span = _collector->_span; | |
| 5286 CMSBitMap* bm = &(_collector->_markBitMap); // shared | |
| 5287 CMSMarkStack* rs = &(_collector->_revisitStack); // shared | |
| 5288 MarkFromDirtyCardsClosure | |
| 5289 greyRescanClosure(_collector, full_span, // entire span of interest | |
| 5290 sp, bm, work_q, rs, cl); | |
| 5291 | |
| 5292 SequentialSubTasksDone* pst = sp->conc_par_seq_tasks(); | |
| 5293 assert(pst->valid(), "Uninitialized use?"); | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5294 uint nth_task = 0; |
| 0 | 5295 const int alignment = CardTableModRefBS::card_size * BitsPerWord; |
| 5296 MemRegion span = sp->used_region(); | |
| 5297 HeapWord* start_addr = span.start(); | |
| 5298 HeapWord* end_addr = (HeapWord*)round_to((intptr_t)span.end(), | |
| 5299 alignment); | |
| 5300 const size_t chunk_size = sp->rescan_task_size(); // in HeapWord units | |
| 5301 assert((HeapWord*)round_to((intptr_t)start_addr, alignment) == | |
| 5302 start_addr, "Check alignment"); | |
| 5303 assert((size_t)round_to((intptr_t)chunk_size, alignment) == | |
| 5304 chunk_size, "Check alignment"); | |
| 5305 | |
| 5306 while (!pst->is_task_claimed(/* reference */ nth_task)) { | |
| 5307 // Having claimed the nth_task, compute corresponding mem-region, | |
| 5308 // which is a-fortiori aligned correctly (i.e. at a MUT bopundary). | |
| 5309 // The alignment restriction ensures that we do not need any | |
| 5310 // synchronization with other gang-workers while setting or | |
| 5311 // clearing bits in thus chunk of the MUT. | |
| 5312 MemRegion this_span = MemRegion(start_addr + nth_task*chunk_size, | |
| 5313 start_addr + (nth_task+1)*chunk_size); | |
| 5314 // The last chunk's end might be way beyond end of the | |
| 5315 // used region. In that case pull back appropriately. | |
| 5316 if (this_span.end() > end_addr) { | |
| 5317 this_span.set_end(end_addr); | |
| 5318 assert(!this_span.is_empty(), "Program logic (calculation of n_tasks)"); | |
| 5319 } | |
| 5320 // Iterate over the dirty cards covering this chunk, marking them | |
| 5321 // precleaned, and setting the corresponding bits in the mod union | |
| 5322 // table. Since we have been careful to partition at Card and MUT-word | |
| 5323 // boundaries no synchronization is needed between parallel threads. | |
| 5324 _collector->_ct->ct_bs()->dirty_card_iterate(this_span, | |
| 5325 &modUnionClosure); | |
| 5326 | |
| 5327 // Having transferred these marks into the modUnionTable, | |
| 5328 // rescan the marked objects on the dirty cards in the modUnionTable. | |
| 5329 // Even if this is at a synchronous collection, the initial marking | |
| 5330 // may have been done during an asynchronous collection so there | |
| 5331 // may be dirty bits in the mod-union table. | |
| 5332 _collector->_modUnionTable.dirty_range_iterate_clear( | |
| 5333 this_span, &greyRescanClosure); | |
| 5334 _collector->_modUnionTable.verifyNoOneBitsInRange( | |
| 5335 this_span.start(), | |
| 5336 this_span.end()); | |
| 5337 } | |
| 5338 pst->all_tasks_completed(); // declare that i am done | |
| 5339 } | |
| 5340 | |
| 5341 // . see if we can share work_queues with ParNew? XXX | |
| 5342 void | |
| 5343 CMSParRemarkTask::do_work_steal(int i, Par_MarkRefsIntoAndScanClosure* cl, | |
| 5344 int* seed) { | |
| 5345 OopTaskQueue* work_q = work_queue(i); | |
| 5346 NOT_PRODUCT(int num_steals = 0;) | |
| 5347 oop obj_to_scan; | |
| 5348 CMSBitMap* bm = &(_collector->_markBitMap); | |
| 5349 | |
| 5350 while (true) { | |
| 5351 // Completely finish any left over work from (an) earlier round(s) | |
| 5352 cl->trim_queue(0); | |
|
679
cea947c8a988
6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops
ysr
parents:
628
diff
changeset
|
5353 size_t num_from_overflow_list = MIN2((size_t)(work_q->max_elems() - work_q->size())/4, |
|
cea947c8a988
6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops
ysr
parents:
628
diff
changeset
|
5354 (size_t)ParGCDesiredObjsFromOverflowList); |
| 0 | 5355 // Now check if there's any work in the overflow list |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5356 // Passing ParallelGCThreads as the third parameter, no_of_gc_threads, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5357 // only affects the number of attempts made to get work from the |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5358 // overflow list and does not affect the number of workers. Just |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5359 // pass ParallelGCThreads so this behavior is unchanged. |
| 0 | 5360 if (_collector->par_take_from_overflow_list(num_from_overflow_list, |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5361 work_q, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5362 ParallelGCThreads)) { |
| 0 | 5363 // found something in global overflow list; |
| 5364 // not yet ready to go stealing work from others. | |
| 5365 // We'd like to assert(work_q->size() != 0, ...) | |
| 5366 // because we just took work from the overflow list, | |
| 5367 // but of course we can't since all of that could have | |
| 5368 // been already stolen from us. | |
| 5369 // "He giveth and He taketh away." | |
| 5370 continue; | |
| 5371 } | |
| 5372 // Verify that we have no work before we resort to stealing | |
| 5373 assert(work_q->size() == 0, "Have work, shouldn't steal"); | |
| 5374 // Try to steal from other queues that have work | |
| 5375 if (task_queues()->steal(i, seed, /* reference */ obj_to_scan)) { | |
| 5376 NOT_PRODUCT(num_steals++;) | |
| 5377 assert(obj_to_scan->is_oop(), "Oops, not an oop!"); | |
| 5378 assert(bm->isMarked((HeapWord*)obj_to_scan), "Stole an unmarked oop?"); | |
| 5379 // Do scanning work | |
| 5380 obj_to_scan->oop_iterate(cl); | |
| 5381 // Loop around, finish this work, and try to steal some more | |
| 5382 } else if (terminator()->offer_termination()) { | |
| 5383 break; // nirvana from the infinite cycle | |
| 5384 } | |
| 5385 } | |
| 5386 NOT_PRODUCT( | |
| 5387 if (PrintCMSStatistics != 0) { | |
| 5388 gclog_or_tty->print("\n\t(%d: stole %d oops)", i, num_steals); | |
| 5389 } | |
| 5390 ) | |
| 5391 assert(work_q->size() == 0 && _collector->overflow_list_is_empty(), | |
| 5392 "Else our work is not yet done"); | |
| 5393 } | |
| 5394 | |
| 5395 // Return a thread-local PLAB recording array, as appropriate. | |
| 5396 void* CMSCollector::get_data_recorder(int thr_num) { | |
| 5397 if (_survivor_plab_array != NULL && | |
| 5398 (CMSPLABRecordAlways || | |
| 5399 (_collectorState > Marking && _collectorState < FinalMarking))) { | |
| 5400 assert(thr_num < (int)ParallelGCThreads, "thr_num is out of bounds"); | |
| 5401 ChunkArray* ca = &_survivor_plab_array[thr_num]; | |
| 5402 ca->reset(); // clear it so that fresh data is recorded | |
| 5403 return (void*) ca; | |
| 5404 } else { | |
| 5405 return NULL; | |
| 5406 } | |
| 5407 } | |
| 5408 | |
| 5409 // Reset all the thread-local PLAB recording arrays | |
| 5410 void CMSCollector::reset_survivor_plab_arrays() { | |
| 5411 for (uint i = 0; i < ParallelGCThreads; i++) { | |
| 5412 _survivor_plab_array[i].reset(); | |
| 5413 } | |
| 5414 } | |
| 5415 | |
| 5416 // Merge the per-thread plab arrays into the global survivor chunk | |
| 5417 // array which will provide the partitioning of the survivor space | |
| 5418 // for CMS rescan. | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5419 void CMSCollector::merge_survivor_plab_arrays(ContiguousSpace* surv, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5420 int no_of_gc_threads) { |
| 0 | 5421 assert(_survivor_plab_array != NULL, "Error"); |
| 5422 assert(_survivor_chunk_array != NULL, "Error"); | |
| 5423 assert(_collectorState == FinalMarking, "Error"); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5424 for (int j = 0; j < no_of_gc_threads; j++) { |
| 0 | 5425 _cursor[j] = 0; |
| 5426 } | |
| 5427 HeapWord* top = surv->top(); | |
| 5428 size_t i; | |
| 5429 for (i = 0; i < _survivor_chunk_capacity; i++) { // all sca entries | |
| 5430 HeapWord* min_val = top; // Higher than any PLAB address | |
| 5431 uint min_tid = 0; // position of min_val this round | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5432 for (int j = 0; j < no_of_gc_threads; j++) { |
| 0 | 5433 ChunkArray* cur_sca = &_survivor_plab_array[j]; |
| 5434 if (_cursor[j] == cur_sca->end()) { | |
| 5435 continue; | |
| 5436 } | |
| 5437 assert(_cursor[j] < cur_sca->end(), "ctl pt invariant"); | |
| 5438 HeapWord* cur_val = cur_sca->nth(_cursor[j]); | |
| 5439 assert(surv->used_region().contains(cur_val), "Out of bounds value"); | |
| 5440 if (cur_val < min_val) { | |
| 5441 min_tid = j; | |
| 5442 min_val = cur_val; | |
| 5443 } else { | |
| 5444 assert(cur_val < top, "All recorded addresses should be less"); | |
| 5445 } | |
| 5446 } | |
| 5447 // At this point min_val and min_tid are respectively | |
| 5448 // the least address in _survivor_plab_array[j]->nth(_cursor[j]) | |
| 5449 // and the thread (j) that witnesses that address. | |
| 5450 // We record this address in the _survivor_chunk_array[i] | |
| 5451 // and increment _cursor[min_tid] prior to the next round i. | |
| 5452 if (min_val == top) { | |
| 5453 break; | |
| 5454 } | |
| 5455 _survivor_chunk_array[i] = min_val; | |
| 5456 _cursor[min_tid]++; | |
| 5457 } | |
| 5458 // We are all done; record the size of the _survivor_chunk_array | |
| 5459 _survivor_chunk_index = i; // exclusive: [0, i) | |
| 5460 if (PrintCMSStatistics > 0) { | |
| 5461 gclog_or_tty->print(" (Survivor:" SIZE_FORMAT "chunks) ", i); | |
| 5462 } | |
| 5463 // Verify that we used up all the recorded entries | |
| 5464 #ifdef ASSERT | |
| 5465 size_t total = 0; | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5466 for (int j = 0; j < no_of_gc_threads; j++) { |
| 0 | 5467 assert(_cursor[j] == _survivor_plab_array[j].end(), "Ctl pt invariant"); |
| 5468 total += _cursor[j]; | |
| 5469 } | |
| 5470 assert(total == _survivor_chunk_index, "Ctl Pt Invariant"); | |
| 5471 // Check that the merged array is in sorted order | |
| 5472 if (total > 0) { | |
| 5473 for (size_t i = 0; i < total - 1; i++) { | |
| 5474 if (PrintCMSStatistics > 0) { | |
| 5475 gclog_or_tty->print(" (chunk" SIZE_FORMAT ":" INTPTR_FORMAT ") ", | |
| 5476 i, _survivor_chunk_array[i]); | |
| 5477 } | |
| 5478 assert(_survivor_chunk_array[i] < _survivor_chunk_array[i+1], | |
| 5479 "Not sorted"); | |
| 5480 } | |
| 5481 } | |
| 5482 #endif // ASSERT | |
| 5483 } | |
| 5484 | |
| 5485 // Set up the space's par_seq_tasks structure for work claiming | |
| 5486 // for parallel rescan of young gen. | |
| 5487 // See ParRescanTask where this is currently used. | |
| 5488 void | |
| 5489 CMSCollector:: | |
| 5490 initialize_sequential_subtasks_for_young_gen_rescan(int n_threads) { | |
| 5491 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 5492 DefNewGeneration* dng = (DefNewGeneration*)_young_gen; | |
| 5493 | |
| 5494 // Eden space | |
| 5495 { | |
| 5496 SequentialSubTasksDone* pst = dng->eden()->par_seq_tasks(); | |
| 5497 assert(!pst->valid(), "Clobbering existing data?"); | |
| 5498 // Each valid entry in [0, _eden_chunk_index) represents a task. | |
| 5499 size_t n_tasks = _eden_chunk_index + 1; | |
| 5500 assert(n_tasks == 1 || _eden_chunk_array != NULL, "Error"); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5501 // Sets the condition for completion of the subtask (how many threads |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5502 // need to finish in order to be done). |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5503 pst->set_n_threads(n_threads); |
| 0 | 5504 pst->set_n_tasks((int)n_tasks); |
| 5505 } | |
| 5506 | |
| 5507 // Merge the survivor plab arrays into _survivor_chunk_array | |
| 5508 if (_survivor_plab_array != NULL) { | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5509 merge_survivor_plab_arrays(dng->from(), n_threads); |
| 0 | 5510 } else { |
| 5511 assert(_survivor_chunk_index == 0, "Error"); | |
| 5512 } | |
| 5513 | |
| 5514 // To space | |
| 5515 { | |
| 5516 SequentialSubTasksDone* pst = dng->to()->par_seq_tasks(); | |
| 5517 assert(!pst->valid(), "Clobbering existing data?"); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5518 // Sets the condition for completion of the subtask (how many threads |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5519 // need to finish in order to be done). |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5520 pst->set_n_threads(n_threads); |
| 0 | 5521 pst->set_n_tasks(1); |
| 5522 assert(pst->valid(), "Error"); | |
| 5523 } | |
| 5524 | |
| 5525 // From space | |
| 5526 { | |
| 5527 SequentialSubTasksDone* pst = dng->from()->par_seq_tasks(); | |
| 5528 assert(!pst->valid(), "Clobbering existing data?"); | |
| 5529 size_t n_tasks = _survivor_chunk_index + 1; | |
| 5530 assert(n_tasks == 1 || _survivor_chunk_array != NULL, "Error"); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5531 // Sets the condition for completion of the subtask (how many threads |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5532 // need to finish in order to be done). |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5533 pst->set_n_threads(n_threads); |
| 0 | 5534 pst->set_n_tasks((int)n_tasks); |
| 5535 assert(pst->valid(), "Error"); | |
| 5536 } | |
| 5537 } | |
| 5538 | |
| 5539 // Parallel version of remark | |
| 5540 void CMSCollector::do_remark_parallel() { | |
| 5541 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5542 FlexibleWorkGang* workers = gch->workers(); |
| 0 | 5543 assert(workers != NULL, "Need parallel worker threads."); |
|
4095
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5544 // Choose to use the number of GC workers most recently set |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5545 // into "active_workers". If active_workers is not set, set it |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5546 // to ParallelGCThreads. |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5547 int n_workers = workers->active_workers(); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5548 if (n_workers == 0) { |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5549 assert(n_workers > 0, "Should have been set during scavenge"); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5550 n_workers = ParallelGCThreads; |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5551 workers->set_active_workers(n_workers); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5552 } |
| 0 | 5553 CompactibleFreeListSpace* cms_space = _cmsGen->cmsSpace(); |
| 5554 CompactibleFreeListSpace* perm_space = _permGen->cmsSpace(); | |
| 5555 | |
| 5556 CMSParRemarkTask tsk(this, | |
| 5557 cms_space, perm_space, | |
| 5558 n_workers, workers, task_queues()); | |
| 5559 | |
| 5560 // Set up for parallel process_strong_roots work. | |
| 5561 gch->set_par_threads(n_workers); | |
| 5562 // We won't be iterating over the cards in the card table updating | |
| 5563 // the younger_gen cards, so we shouldn't call the following else | |
| 5564 // the verification code as well as subsequent younger_refs_iterate | |
| 5565 // code would get confused. XXX | |
| 5566 // gch->rem_set()->prepare_for_younger_refs_iterate(true); // parallel | |
| 5567 | |
| 5568 // The young gen rescan work will not be done as part of | |
| 5569 // process_strong_roots (which currently doesn't knw how to | |
| 5570 // parallelize such a scan), but rather will be broken up into | |
| 5571 // a set of parallel tasks (via the sampling that the [abortable] | |
| 5572 // preclean phase did of EdenSpace, plus the [two] tasks of | |
| 5573 // scanning the [two] survivor spaces. Further fine-grain | |
| 5574 // parallelization of the scanning of the survivor spaces | |
| 5575 // themselves, and of precleaning of the younger gen itself | |
| 5576 // is deferred to the future. | |
| 5577 initialize_sequential_subtasks_for_young_gen_rescan(n_workers); | |
| 5578 | |
| 5579 // The dirty card rescan work is broken up into a "sequence" | |
| 5580 // of parallel tasks (per constituent space) that are dynamically | |
| 5581 // claimed by the parallel threads. | |
| 5582 cms_space->initialize_sequential_subtasks_for_rescan(n_workers); | |
| 5583 perm_space->initialize_sequential_subtasks_for_rescan(n_workers); | |
| 5584 | |
| 5585 // It turns out that even when we're using 1 thread, doing the work in a | |
| 5586 // separate thread causes wide variance in run times. We can't help this | |
| 5587 // in the multi-threaded case, but we special-case n=1 here to get | |
| 5588 // repeatable measurements of the 1-thread overhead of the parallel code. | |
| 5589 if (n_workers > 1) { | |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5590 // Make refs discovery MT-safe, if it isn't already: it may not |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5591 // necessarily be so, since it's possible that we are doing |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5592 // ST marking. |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5593 ReferenceProcessorMTDiscoveryMutator mt(ref_processor(), true); |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5594 GenCollectedHeap::StrongRootsScope srs(gch); |
| 0 | 5595 workers->run_task(&tsk); |
| 5596 } else { | |
|
4876
be649fefcdc2
7134655: Crash in reference processing when doing single-threaded remarking
stefank
parents:
4728
diff
changeset
|
5597 ReferenceProcessorMTDiscoveryMutator mt(ref_processor(), false); |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5598 GenCollectedHeap::StrongRootsScope srs(gch); |
| 0 | 5599 tsk.work(0); |
| 5600 } | |
| 5601 gch->set_par_threads(0); // 0 ==> non-parallel. | |
| 5602 // restore, single-threaded for now, any preserved marks | |
| 5603 // as a result of work_q overflow | |
| 5604 restore_preserved_marks_if_any(); | |
| 5605 } | |
| 5606 | |
| 5607 // Non-parallel version of remark | |
| 5608 void CMSCollector::do_remark_non_parallel() { | |
| 5609 ResourceMark rm; | |
| 5610 HandleMark hm; | |
| 5611 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
|
4876
be649fefcdc2
7134655: Crash in reference processing when doing single-threaded remarking
stefank
parents:
4728
diff
changeset
|
5612 ReferenceProcessorMTDiscoveryMutator mt(ref_processor(), false); |
|
be649fefcdc2
7134655: Crash in reference processing when doing single-threaded remarking
stefank
parents:
4728
diff
changeset
|
5613 |
| 0 | 5614 MarkRefsIntoAndScanClosure |
| 5615 mrias_cl(_span, ref_processor(), &_markBitMap, &_modUnionTable, | |
| 5616 &_markStack, &_revisitStack, this, | |
| 5617 false /* should_yield */, false /* not precleaning */); | |
| 5618 MarkFromDirtyCardsClosure | |
| 5619 markFromDirtyCardsClosure(this, _span, | |
| 5620 NULL, // space is set further below | |
| 5621 &_markBitMap, &_markStack, &_revisitStack, | |
| 5622 &mrias_cl); | |
| 5623 { | |
| 5624 TraceTime t("grey object rescan", PrintGCDetails, false, gclog_or_tty); | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
5625 // Iterate over the dirty cards, setting the corresponding bits in the |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
5626 // mod union table. |
| 0 | 5627 { |
| 5628 ModUnionClosure modUnionClosure(&_modUnionTable); | |
| 5629 _ct->ct_bs()->dirty_card_iterate( | |
| 5630 _cmsGen->used_region(), | |
| 5631 &modUnionClosure); | |
| 5632 _ct->ct_bs()->dirty_card_iterate( | |
| 5633 _permGen->used_region(), | |
| 5634 &modUnionClosure); | |
| 5635 } | |
| 5636 // Having transferred these marks into the modUnionTable, we just need | |
| 5637 // to rescan the marked objects on the dirty cards in the modUnionTable. | |
| 5638 // The initial marking may have been done during an asynchronous | |
| 5639 // collection so there may be dirty bits in the mod-union table. | |
| 5640 const int alignment = | |
| 5641 CardTableModRefBS::card_size * BitsPerWord; | |
| 5642 { | |
| 5643 // ... First handle dirty cards in CMS gen | |
| 5644 markFromDirtyCardsClosure.set_space(_cmsGen->cmsSpace()); | |
| 5645 MemRegion ur = _cmsGen->used_region(); | |
| 5646 HeapWord* lb = ur.start(); | |
| 5647 HeapWord* ub = (HeapWord*)round_to((intptr_t)ur.end(), alignment); | |
| 5648 MemRegion cms_span(lb, ub); | |
| 5649 _modUnionTable.dirty_range_iterate_clear(cms_span, | |
| 5650 &markFromDirtyCardsClosure); | |
| 5651 verify_work_stacks_empty(); | |
| 5652 if (PrintCMSStatistics != 0) { | |
| 5653 gclog_or_tty->print(" (re-scanned "SIZE_FORMAT" dirty cards in cms gen) ", | |
| 5654 markFromDirtyCardsClosure.num_dirty_cards()); | |
| 5655 } | |
| 5656 } | |
| 5657 { | |
| 5658 // .. and then repeat for dirty cards in perm gen | |
| 5659 markFromDirtyCardsClosure.set_space(_permGen->cmsSpace()); | |
| 5660 MemRegion ur = _permGen->used_region(); | |
| 5661 HeapWord* lb = ur.start(); | |
| 5662 HeapWord* ub = (HeapWord*)round_to((intptr_t)ur.end(), alignment); | |
| 5663 MemRegion perm_span(lb, ub); | |
| 5664 _modUnionTable.dirty_range_iterate_clear(perm_span, | |
| 5665 &markFromDirtyCardsClosure); | |
| 5666 verify_work_stacks_empty(); | |
| 5667 if (PrintCMSStatistics != 0) { | |
| 5668 gclog_or_tty->print(" (re-scanned "SIZE_FORMAT" dirty cards in perm gen) ", | |
| 5669 markFromDirtyCardsClosure.num_dirty_cards()); | |
| 5670 } | |
| 5671 } | |
| 5672 } | |
| 5673 if (VerifyDuringGC && | |
| 5674 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { | |
| 5675 HandleMark hm; // Discard invalid handles created during verification | |
| 5676 Universe::verify(true); | |
| 5677 } | |
| 5678 { | |
| 5679 TraceTime t("root rescan", PrintGCDetails, false, gclog_or_tty); | |
| 5680 | |
| 5681 verify_work_stacks_empty(); | |
| 5682 | |
| 5683 gch->rem_set()->prepare_for_younger_refs_iterate(false); // Not parallel. | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5684 GenCollectedHeap::StrongRootsScope srs(gch); |
| 0 | 5685 gch->gen_process_strong_roots(_cmsGen->level(), |
| 5686 true, // younger gens as roots | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5687 false, // use the local StrongRootsScope |
| 0 | 5688 true, // collecting perm gen |
| 5689 SharedHeap::ScanningOption(roots_scanning_options()), | |
|
989
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5690 &mrias_cl, |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5691 true, // walk code active on stacks |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5692 NULL); |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5693 assert(should_unload_classes() |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5694 || (roots_scanning_options() & SharedHeap::SO_CodeCache), |
|
148e5441d916
6863023: need non-perm oops in code cache for JSR 292
jrose
parents:
798
diff
changeset
|
5695 "if we didn't scan the code cache, we have to be ready to drop nmethods with expired weak oops"); |
| 0 | 5696 } |
| 5697 verify_work_stacks_empty(); | |
| 5698 // Restore evacuated mark words, if any, used for overflow list links | |
| 5699 if (!CMSOverflowEarlyRestoration) { | |
| 5700 restore_preserved_marks_if_any(); | |
| 5701 } | |
| 5702 verify_overflow_empty(); | |
| 5703 } | |
| 5704 | |
| 5705 //////////////////////////////////////////////////////// | |
| 5706 // Parallel Reference Processing Task Proxy Class | |
| 5707 //////////////////////////////////////////////////////// | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5708 class CMSRefProcTaskProxy: public AbstractGangTaskWOopQueues { |
| 0 | 5709 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask; |
| 5710 CMSCollector* _collector; | |
| 5711 CMSBitMap* _mark_bit_map; | |
|
143
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
5712 const MemRegion _span; |
| 0 | 5713 ProcessTask& _task; |
| 5714 | |
| 5715 public: | |
| 5716 CMSRefProcTaskProxy(ProcessTask& task, | |
| 5717 CMSCollector* collector, | |
| 5718 const MemRegion& span, | |
| 5719 CMSBitMap* mark_bit_map, | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5720 AbstractWorkGang* workers, |
| 0 | 5721 OopTaskQueueSet* task_queues): |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5722 // XXX Should superclass AGTWOQ also know about AWG since it knows |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5723 // about the task_queues used by the AWG? Then it could initialize |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5724 // the terminator() object. See 6984287. The set_for_termination() |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5725 // below is a temporary band-aid for the regression in 6984287. |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5726 AbstractGangTaskWOopQueues("Process referents by policy in parallel", |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5727 task_queues), |
| 0 | 5728 _task(task), |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5729 _collector(collector), _span(span), _mark_bit_map(mark_bit_map) |
|
2369
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5730 { |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5731 assert(_collector->_span.equals(_span) && !_span.is_empty(), |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5732 "Inconsistency in _span"); |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5733 set_for_termination(workers->active_workers()); |
|
92da084fefc9
6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents:
2365
diff
changeset
|
5734 } |
| 0 | 5735 |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5736 OopTaskQueueSet* task_queues() { return queues(); } |
| 0 | 5737 |
| 5738 OopTaskQueue* work_queue(int i) { return task_queues()->queue(i); } | |
| 5739 | |
| 5740 void do_work_steal(int i, | |
| 5741 CMSParDrainMarkingStackClosure* drain, | |
| 5742 CMSParKeepAliveClosure* keep_alive, | |
| 5743 int* seed); | |
| 5744 | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5745 virtual void work(uint worker_id); |
| 0 | 5746 }; |
| 5747 | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5748 void CMSRefProcTaskProxy::work(uint worker_id) { |
|
143
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
5749 assert(_collector->_span.equals(_span), "Inconsistency in _span"); |
| 0 | 5750 CMSParKeepAliveClosure par_keep_alive(_collector, _span, |
| 935 | 5751 _mark_bit_map, |
| 5752 &_collector->_revisitStack, | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5753 work_queue(worker_id)); |
| 0 | 5754 CMSParDrainMarkingStackClosure par_drain_stack(_collector, _span, |
| 935 | 5755 _mark_bit_map, |
| 5756 &_collector->_revisitStack, | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5757 work_queue(worker_id)); |
|
143
b5489bb705c9
6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled
ysr
parents:
113
diff
changeset
|
5758 CMSIsAliveClosure is_alive_closure(_span, _mark_bit_map); |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5759 _task.work(worker_id, is_alive_closure, par_keep_alive, par_drain_stack); |
| 0 | 5760 if (_task.marks_oops_alive()) { |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5761 do_work_steal(worker_id, &par_drain_stack, &par_keep_alive, |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5762 _collector->hash_seed(worker_id)); |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5763 } |
|
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5764 assert(work_queue(worker_id)->size() == 0, "work_queue should be empty"); |
| 0 | 5765 assert(_collector->_overflow_list == NULL, "non-empty _overflow_list"); |
| 5766 } | |
| 5767 | |
| 5768 class CMSRefEnqueueTaskProxy: public AbstractGangTask { | |
| 5769 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask; | |
| 5770 EnqueueTask& _task; | |
| 5771 | |
| 5772 public: | |
| 5773 CMSRefEnqueueTaskProxy(EnqueueTask& task) | |
| 5774 : AbstractGangTask("Enqueue reference objects in parallel"), | |
| 5775 _task(task) | |
| 5776 { } | |
| 5777 | |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5778 virtual void work(uint worker_id) |
| 0 | 5779 { |
|
4728
441e946dc1af
7121618: Change type of number of GC workers to unsigned int.
jmasa
parents:
4128
diff
changeset
|
5780 _task.work(worker_id); |
| 0 | 5781 } |
| 5782 }; | |
| 5783 | |
| 5784 CMSParKeepAliveClosure::CMSParKeepAliveClosure(CMSCollector* collector, | |
| 935 | 5785 MemRegion span, CMSBitMap* bit_map, CMSMarkStack* revisit_stack, |
| 5786 OopTaskQueue* work_queue): | |
| 5787 Par_KlassRememberingOopClosure(collector, NULL, revisit_stack), | |
| 0 | 5788 _span(span), |
| 5789 _bit_map(bit_map), | |
| 5790 _work_queue(work_queue), | |
| 935 | 5791 _mark_and_push(collector, span, bit_map, revisit_stack, work_queue), |
| 0 | 5792 _low_water_mark(MIN2((uint)(work_queue->max_elems()/4), |
| 5793 (uint)(CMSWorkQueueDrainThreshold * ParallelGCThreads))) | |
| 5794 { } | |
| 5795 | |
| 5796 // . see if we can share work_queues with ParNew? XXX | |
| 5797 void CMSRefProcTaskProxy::do_work_steal(int i, | |
| 5798 CMSParDrainMarkingStackClosure* drain, | |
| 5799 CMSParKeepAliveClosure* keep_alive, | |
| 5800 int* seed) { | |
| 5801 OopTaskQueue* work_q = work_queue(i); | |
| 5802 NOT_PRODUCT(int num_steals = 0;) | |
| 5803 oop obj_to_scan; | |
| 5804 | |
| 5805 while (true) { | |
| 5806 // Completely finish any left over work from (an) earlier round(s) | |
| 5807 drain->trim_queue(0); | |
|
679
cea947c8a988
6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops
ysr
parents:
628
diff
changeset
|
5808 size_t num_from_overflow_list = MIN2((size_t)(work_q->max_elems() - work_q->size())/4, |
|
cea947c8a988
6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops
ysr
parents:
628
diff
changeset
|
5809 (size_t)ParGCDesiredObjsFromOverflowList); |
| 0 | 5810 // Now check if there's any work in the overflow list |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5811 // Passing ParallelGCThreads as the third parameter, no_of_gc_threads, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5812 // only affects the number of attempts made to get work from the |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5813 // overflow list and does not affect the number of workers. Just |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5814 // pass ParallelGCThreads so this behavior is unchanged. |
| 0 | 5815 if (_collector->par_take_from_overflow_list(num_from_overflow_list, |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5816 work_q, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5817 ParallelGCThreads)) { |
| 0 | 5818 // Found something in global overflow list; |
| 5819 // not yet ready to go stealing work from others. | |
| 5820 // We'd like to assert(work_q->size() != 0, ...) | |
| 5821 // because we just took work from the overflow list, | |
| 5822 // but of course we can't, since all of that might have | |
| 5823 // been already stolen from us. | |
| 5824 continue; | |
| 5825 } | |
| 5826 // Verify that we have no work before we resort to stealing | |
| 5827 assert(work_q->size() == 0, "Have work, shouldn't steal"); | |
| 5828 // Try to steal from other queues that have work | |
| 5829 if (task_queues()->steal(i, seed, /* reference */ obj_to_scan)) { | |
| 5830 NOT_PRODUCT(num_steals++;) | |
| 5831 assert(obj_to_scan->is_oop(), "Oops, not an oop!"); | |
| 5832 assert(_mark_bit_map->isMarked((HeapWord*)obj_to_scan), "Stole an unmarked oop?"); | |
| 5833 // Do scanning work | |
| 5834 obj_to_scan->oop_iterate(keep_alive); | |
| 5835 // Loop around, finish this work, and try to steal some more | |
| 5836 } else if (terminator()->offer_termination()) { | |
| 5837 break; // nirvana from the infinite cycle | |
| 5838 } | |
| 5839 } | |
| 5840 NOT_PRODUCT( | |
| 5841 if (PrintCMSStatistics != 0) { | |
| 5842 gclog_or_tty->print("\n\t(%d: stole %d oops)", i, num_steals); | |
| 5843 } | |
| 5844 ) | |
| 5845 } | |
| 5846 | |
| 5847 void CMSRefProcTaskExecutor::execute(ProcessTask& task) | |
| 5848 { | |
| 5849 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5850 FlexibleWorkGang* workers = gch->workers(); |
| 0 | 5851 assert(workers != NULL, "Need parallel worker threads."); |
| 5852 CMSRefProcTaskProxy rp_task(task, &_collector, | |
| 5853 _collector.ref_processor()->span(), | |
| 5854 _collector.markBitMap(), | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5855 workers, _collector.task_queues()); |
| 0 | 5856 workers->run_task(&rp_task); |
| 5857 } | |
| 5858 | |
| 5859 void CMSRefProcTaskExecutor::execute(EnqueueTask& task) | |
| 5860 { | |
| 5861 | |
| 5862 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5863 FlexibleWorkGang* workers = gch->workers(); |
| 0 | 5864 assert(workers != NULL, "Need parallel worker threads."); |
| 5865 CMSRefEnqueueTaskProxy enq_task(task); | |
| 5866 workers->run_task(&enq_task); | |
| 5867 } | |
| 5868 | |
| 5869 void CMSCollector::refProcessingWork(bool asynch, bool clear_all_soft_refs) { | |
| 5870 | |
| 5871 ResourceMark rm; | |
| 5872 HandleMark hm; | |
| 5873 | |
| 5874 ReferenceProcessor* rp = ref_processor(); | |
| 5875 assert(rp->span().equals(_span), "Spans should be equal"); | |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
5876 assert(!rp->enqueuing_is_done(), "Enqueuing should not be complete"); |
|
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
5877 // Process weak references. |
|
457
27a80744a83b
6778647: snap(), snap_policy() should be renamed setup(), setup_policy()
ysr
parents:
453
diff
changeset
|
5878 rp->setup_policy(clear_all_soft_refs); |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
5879 verify_work_stacks_empty(); |
|
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
5880 |
| 0 | 5881 CMSKeepAliveClosure cmsKeepAliveClosure(this, _span, &_markBitMap, |
| 935 | 5882 &_markStack, &_revisitStack, |
| 5883 false /* !preclean */); | |
| 0 | 5884 CMSDrainMarkingStackClosure cmsDrainMarkingStackClosure(this, |
| 5885 _span, &_markBitMap, &_markStack, | |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
5886 &cmsKeepAliveClosure, false /* !preclean */); |
| 0 | 5887 { |
| 5888 TraceTime t("weak refs processing", PrintGCDetails, false, gclog_or_tty); | |
| 5889 if (rp->processing_is_mt()) { | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5890 // Set the degree of MT here. If the discovery is done MT, there |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5891 // may have been a different number of threads doing the discovery |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5892 // and a different number of discovered lists may have Ref objects. |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5893 // That is OK as long as the Reference lists are balanced (see |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5894 // balance_all_queues() and balance_queues()). |
|
4095
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5895 GenCollectedHeap* gch = GenCollectedHeap::heap(); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5896 int active_workers = ParallelGCThreads; |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5897 FlexibleWorkGang* workers = gch->workers(); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5898 if (workers != NULL) { |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5899 active_workers = workers->active_workers(); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5900 // The expectation is that active_workers will have already |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5901 // been set to a reasonable value. If it has not been set, |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5902 // investigate. |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5903 assert(active_workers > 0, "Should have been set during scavenge"); |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5904 } |
|
bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
jmasa
parents:
3979
diff
changeset
|
5905 rp->set_active_mt_degree(active_workers); |
| 0 | 5906 CMSRefProcTaskExecutor task_executor(*this); |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
5907 rp->process_discovered_references(&_is_alive_closure, |
| 0 | 5908 &cmsKeepAliveClosure, |
| 5909 &cmsDrainMarkingStackClosure, | |
| 5910 &task_executor); | |
| 5911 } else { | |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
5912 rp->process_discovered_references(&_is_alive_closure, |
| 0 | 5913 &cmsKeepAliveClosure, |
| 5914 &cmsDrainMarkingStackClosure, | |
| 5915 NULL); | |
| 5916 } | |
| 5917 verify_work_stacks_empty(); | |
| 5918 } | |
| 5919 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
5920 if (should_unload_classes()) { |
| 0 | 5921 { |
| 5922 TraceTime t("class unloading", PrintGCDetails, false, gclog_or_tty); | |
| 5923 | |
| 5924 // Follow SystemDictionary roots and unload classes | |
| 5925 bool purged_class = SystemDictionary::do_unloading(&_is_alive_closure); | |
| 5926 | |
| 5927 // Follow CodeCache roots and unload any methods marked for unloading | |
| 5928 CodeCache::do_unloading(&_is_alive_closure, | |
| 5929 &cmsKeepAliveClosure, | |
| 5930 purged_class); | |
| 5931 | |
| 5932 cmsDrainMarkingStackClosure.do_void(); | |
| 5933 verify_work_stacks_empty(); | |
| 5934 | |
| 5935 // Update subklass/sibling/implementor links in KlassKlass descendants | |
| 5936 assert(!_revisitStack.isEmpty(), "revisit stack should not be empty"); | |
| 5937 oop k; | |
| 5938 while ((k = _revisitStack.pop()) != NULL) { | |
| 5939 ((Klass*)(oopDesc*)k)->follow_weak_klass_links( | |
| 5940 &_is_alive_closure, | |
| 5941 &cmsKeepAliveClosure); | |
| 5942 } | |
| 5943 assert(!ClassUnloading || | |
| 5944 (_markStack.isEmpty() && overflow_list_is_empty()), | |
| 5945 "Should not have found new reachable objects"); | |
| 5946 assert(_revisitStack.isEmpty(), "revisit stack should have been drained"); | |
| 5947 cmsDrainMarkingStackClosure.do_void(); | |
| 5948 verify_work_stacks_empty(); | |
| 5949 } | |
| 5950 | |
| 5951 { | |
|
2379
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5952 TraceTime t("scrub symbol table", PrintGCDetails, false, gclog_or_tty); |
|
2177
3582bf76420e
6990754: Use native memory and reference counting to implement SymbolTable
coleenp
parents:
2147
diff
changeset
|
5953 // Clean up unreferenced symbols in symbol table. |
|
3582bf76420e
6990754: Use native memory and reference counting to implement SymbolTable
coleenp
parents:
2147
diff
changeset
|
5954 SymbolTable::unlink(); |
| 0 | 5955 } |
| 5956 } | |
| 5957 | |
|
2379
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5958 if (should_unload_classes() || !JavaObjectsInPerm) { |
|
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5959 TraceTime t("scrub string table", PrintGCDetails, false, gclog_or_tty); |
|
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5960 // Now clean up stale oops in StringTable |
|
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5961 StringTable::unlink(&_is_alive_closure); |
|
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5962 } |
|
b099aaf51bf8
6962931: move interned strings out of the perm gen
jcoomes
parents:
2369
diff
changeset
|
5963 |
| 0 | 5964 verify_work_stacks_empty(); |
| 5965 // Restore any preserved marks as a result of mark stack or | |
| 5966 // work queue overflow | |
| 5967 restore_preserved_marks_if_any(); // done single-threaded for now | |
| 5968 | |
| 5969 rp->set_enqueuing_is_done(true); | |
| 5970 if (rp->processing_is_mt()) { | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
5971 rp->balance_all_queues(); |
| 0 | 5972 CMSRefProcTaskExecutor task_executor(*this); |
| 5973 rp->enqueue_discovered_references(&task_executor); | |
| 5974 } else { | |
| 5975 rp->enqueue_discovered_references(NULL); | |
| 5976 } | |
| 5977 rp->verify_no_references_recorded(); | |
| 5978 assert(!rp->discovery_enabled(), "should have been disabled"); | |
| 5979 } | |
| 5980 | |
| 5981 #ifndef PRODUCT | |
| 5982 void CMSCollector::check_correct_thread_executing() { | |
| 5983 Thread* t = Thread::current(); | |
| 5984 // Only the VM thread or the CMS thread should be here. | |
| 5985 assert(t->is_ConcurrentGC_thread() || t->is_VM_thread(), | |
| 5986 "Unexpected thread type"); | |
| 5987 // If this is the vm thread, the foreground process | |
| 5988 // should not be waiting. Note that _foregroundGCIsActive is | |
| 5989 // true while the foreground collector is waiting. | |
| 5990 if (_foregroundGCShouldWait) { | |
| 5991 // We cannot be the VM thread | |
| 5992 assert(t->is_ConcurrentGC_thread(), | |
| 5993 "Should be CMS thread"); | |
| 5994 } else { | |
| 5995 // We can be the CMS thread only if we are in a stop-world | |
| 5996 // phase of CMS collection. | |
| 5997 if (t->is_ConcurrentGC_thread()) { | |
| 5998 assert(_collectorState == InitialMarking || | |
| 5999 _collectorState == FinalMarking, | |
| 6000 "Should be a stop-world phase"); | |
| 6001 // The CMS thread should be holding the CMS_token. | |
| 6002 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 6003 "Potential interference with concurrently " | |
| 6004 "executing VM thread"); | |
| 6005 } | |
| 6006 } | |
| 6007 } | |
| 6008 #endif | |
| 6009 | |
| 6010 void CMSCollector::sweep(bool asynch) { | |
| 6011 assert(_collectorState == Sweeping, "just checking"); | |
| 6012 check_correct_thread_executing(); | |
| 6013 verify_work_stacks_empty(); | |
| 6014 verify_overflow_empty(); | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6015 increment_sweep_count(); |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
6016 TraceCMSMemoryManagerStats tms(_collectorState,GenCollectedHeap::heap()->gc_cause()); |
|
1703
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
6017 |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6018 _inter_sweep_timer.stop(); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6019 _inter_sweep_estimate.sample(_inter_sweep_timer.seconds()); |
| 0 | 6020 size_policy()->avg_cms_free_at_sweep()->sample(_cmsGen->free()); |
| 6021 | |
| 6022 // PermGen verification support: If perm gen sweeping is disabled in | |
| 6023 // this cycle, we preserve the perm gen object "deadness" information | |
| 6024 // in the perm_gen_verify_bit_map. In order to do that we traverse | |
| 6025 // all blocks in perm gen and mark all dead objects. | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6026 if (verifying() && !should_unload_classes()) { |
| 0 | 6027 assert(perm_gen_verify_bit_map()->sizeInBits() != 0, |
| 6028 "Should have already been allocated"); | |
| 6029 MarkDeadObjectsClosure mdo(this, _permGen->cmsSpace(), | |
| 6030 markBitMap(), perm_gen_verify_bit_map()); | |
|
7
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6031 if (asynch) { |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6032 CMSTokenSyncWithLocks ts(true, _permGen->freelistLock(), |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6033 bitMapLock()); |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6034 _permGen->cmsSpace()->blk_iterate(&mdo); |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6035 } else { |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6036 // In the case of synchronous sweep, we already have |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6037 // the requisite locks/tokens. |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6038 _permGen->cmsSpace()->blk_iterate(&mdo); |
|
2faf283ce688
6621144: CMS: assertion failure "is_cms_thread == Thread::current()->is_ConcurrentGC_thread()"
ysr
parents:
0
diff
changeset
|
6039 } |
| 0 | 6040 } |
| 6041 | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6042 assert(!_intra_sweep_timer.is_active(), "Should not be active"); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6043 _intra_sweep_timer.reset(); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6044 _intra_sweep_timer.start(); |
| 0 | 6045 if (asynch) { |
| 6046 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 6047 CMSPhaseAccounting pa(this, "sweep", !PrintGCDetails); | |
| 6048 // First sweep the old gen then the perm gen | |
| 6049 { | |
| 6050 CMSTokenSyncWithLocks ts(true, _cmsGen->freelistLock(), | |
| 6051 bitMapLock()); | |
| 6052 sweepWork(_cmsGen, asynch); | |
| 6053 } | |
| 6054 | |
| 6055 // Now repeat for perm gen | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6056 if (should_unload_classes()) { |
| 0 | 6057 CMSTokenSyncWithLocks ts(true, _permGen->freelistLock(), |
| 6058 bitMapLock()); | |
| 6059 sweepWork(_permGen, asynch); | |
| 6060 } | |
| 6061 | |
| 6062 // Update Universe::_heap_*_at_gc figures. | |
| 6063 // We need all the free list locks to make the abstract state | |
| 6064 // transition from Sweeping to Resetting. See detailed note | |
| 6065 // further below. | |
| 6066 { | |
| 6067 CMSTokenSyncWithLocks ts(true, _cmsGen->freelistLock(), | |
| 6068 _permGen->freelistLock()); | |
| 6069 // Update heap occupancy information which is used as | |
| 6070 // input to soft ref clearing policy at the next gc. | |
| 6071 Universe::update_heap_info_at_gc(); | |
| 6072 _collectorState = Resizing; | |
| 6073 } | |
| 6074 } else { | |
| 6075 // already have needed locks | |
| 6076 sweepWork(_cmsGen, asynch); | |
| 6077 | |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6078 if (should_unload_classes()) { |
| 0 | 6079 sweepWork(_permGen, asynch); |
| 6080 } | |
| 6081 // Update heap occupancy information which is used as | |
| 6082 // input to soft ref clearing policy at the next gc. | |
| 6083 Universe::update_heap_info_at_gc(); | |
| 6084 _collectorState = Resizing; | |
| 6085 } | |
| 6086 verify_work_stacks_empty(); | |
| 6087 verify_overflow_empty(); | |
| 6088 | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6089 _intra_sweep_timer.stop(); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6090 _intra_sweep_estimate.sample(_intra_sweep_timer.seconds()); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6091 |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6092 _inter_sweep_timer.reset(); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6093 _inter_sweep_timer.start(); |
| 0 | 6094 |
| 4911 | 6095 // We need to use a monotonically non-deccreasing time in ms |
| 6096 // or we will see time-warp warnings and os::javaTimeMillis() | |
| 6097 // does not guarantee monotonicity. | |
| 6098 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; | |
| 6099 update_time_of_last_gc(now); | |
| 0 | 6100 |
| 6101 // NOTE on abstract state transitions: | |
| 6102 // Mutators allocate-live and/or mark the mod-union table dirty | |
| 6103 // based on the state of the collection. The former is done in | |
| 6104 // the interval [Marking, Sweeping] and the latter in the interval | |
| 6105 // [Marking, Sweeping). Thus the transitions into the Marking state | |
| 6106 // and out of the Sweeping state must be synchronously visible | |
| 6107 // globally to the mutators. | |
| 6108 // The transition into the Marking state happens with the world | |
| 6109 // stopped so the mutators will globally see it. Sweeping is | |
| 6110 // done asynchronously by the background collector so the transition | |
| 6111 // from the Sweeping state to the Resizing state must be done | |
| 6112 // under the freelistLock (as is the check for whether to | |
| 6113 // allocate-live and whether to dirty the mod-union table). | |
| 6114 assert(_collectorState == Resizing, "Change of collector state to" | |
| 6115 " Resizing must be done under the freelistLocks (plural)"); | |
| 6116 | |
|
1888
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
6117 // Now that sweeping has been completed, we clear |
|
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
6118 // the incremental_collection_failed flag, |
| 0 | 6119 // thus inviting a younger gen collection to promote into |
| 6120 // this generation. If such a promotion may still fail, | |
| 6121 // the flag will be set again when a young collection is | |
| 6122 // attempted. | |
| 6123 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
|
1888
a7214d79fcf1
6896603: CMS/GCH: collection_attempt_is_safe() ergo should use more recent data
ysr
parents:
1837
diff
changeset
|
6124 gch->clear_incremental_collection_failed(); // Worth retrying as fresh space may have been freed up |
| 0 | 6125 gch->update_full_collections_completed(_collection_count_start); |
| 6126 } | |
| 6127 | |
| 6128 // FIX ME!!! Looks like this belongs in CFLSpace, with | |
| 6129 // CMSGen merely delegating to it. | |
| 6130 void ConcurrentMarkSweepGeneration::setNearLargestChunk() { | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6131 double nearLargestPercent = FLSLargestBlockCoalesceProximity; |
| 0 | 6132 HeapWord* minAddr = _cmsSpace->bottom(); |
| 6133 HeapWord* largestAddr = | |
| 6134 (HeapWord*) _cmsSpace->dictionary()->findLargestDict(); | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6135 if (largestAddr == NULL) { |
| 0 | 6136 // The dictionary appears to be empty. In this case |
| 6137 // try to coalesce at the end of the heap. | |
| 6138 largestAddr = _cmsSpace->end(); | |
| 6139 } | |
| 6140 size_t largestOffset = pointer_delta(largestAddr, minAddr); | |
| 6141 size_t nearLargestOffset = | |
| 6142 (size_t)((double)largestOffset * nearLargestPercent) - MinChunkSize; | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6143 if (PrintFLSStatistics != 0) { |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6144 gclog_or_tty->print_cr( |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6145 "CMS: Large Block: " PTR_FORMAT ";" |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6146 " Proximity: " PTR_FORMAT " -> " PTR_FORMAT, |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6147 largestAddr, |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6148 _cmsSpace->nearLargestChunk(), minAddr + nearLargestOffset); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6149 } |
| 0 | 6150 _cmsSpace->set_nearLargestChunk(minAddr + nearLargestOffset); |
| 6151 } | |
| 6152 | |
| 6153 bool ConcurrentMarkSweepGeneration::isNearLargestChunk(HeapWord* addr) { | |
| 6154 return addr >= _cmsSpace->nearLargestChunk(); | |
| 6155 } | |
| 6156 | |
| 6157 FreeChunk* ConcurrentMarkSweepGeneration::find_chunk_at_end() { | |
| 6158 return _cmsSpace->find_chunk_at_end(); | |
| 6159 } | |
| 6160 | |
| 6161 void ConcurrentMarkSweepGeneration::update_gc_stats(int current_level, | |
| 6162 bool full) { | |
| 6163 // The next lower level has been collected. Gather any statistics | |
| 6164 // that are of interest at this point. | |
| 6165 if (!full && (current_level + 1) == level()) { | |
| 6166 // Gather statistics on the young generation collection. | |
| 6167 collector()->stats().record_gc0_end(used()); | |
| 6168 } | |
| 6169 } | |
| 6170 | |
| 6171 CMSAdaptiveSizePolicy* ConcurrentMarkSweepGeneration::size_policy() { | |
| 6172 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 6173 assert(gch->kind() == CollectedHeap::GenCollectedHeap, | |
| 6174 "Wrong type of heap"); | |
| 6175 CMSAdaptiveSizePolicy* sp = (CMSAdaptiveSizePolicy*) | |
| 6176 gch->gen_policy()->size_policy(); | |
| 6177 assert(sp->is_gc_cms_adaptive_size_policy(), | |
| 6178 "Wrong type of size policy"); | |
| 6179 return sp; | |
| 6180 } | |
| 6181 | |
| 6182 void ConcurrentMarkSweepGeneration::rotate_debug_collection_type() { | |
| 6183 if (PrintGCDetails && Verbose) { | |
| 6184 gclog_or_tty->print("Rotate from %d ", _debug_collection_type); | |
| 6185 } | |
| 6186 _debug_collection_type = (CollectionTypes) (_debug_collection_type + 1); | |
| 6187 _debug_collection_type = | |
| 6188 (CollectionTypes) (_debug_collection_type % Unknown_collection_type); | |
| 6189 if (PrintGCDetails && Verbose) { | |
| 6190 gclog_or_tty->print_cr("to %d ", _debug_collection_type); | |
| 6191 } | |
| 6192 } | |
| 6193 | |
| 6194 void CMSCollector::sweepWork(ConcurrentMarkSweepGeneration* gen, | |
| 6195 bool asynch) { | |
| 6196 // We iterate over the space(s) underlying this generation, | |
| 6197 // checking the mark bit map to see if the bits corresponding | |
| 6198 // to specific blocks are marked or not. Blocks that are | |
| 6199 // marked are live and are not swept up. All remaining blocks | |
| 6200 // are swept up, with coalescing on-the-fly as we sweep up | |
| 6201 // contiguous free and/or garbage blocks: | |
| 6202 // We need to ensure that the sweeper synchronizes with allocators | |
| 6203 // and stop-the-world collectors. In particular, the following | |
| 6204 // locks are used: | |
| 6205 // . CMS token: if this is held, a stop the world collection cannot occur | |
| 6206 // . freelistLock: if this is held no allocation can occur from this | |
| 6207 // generation by another thread | |
| 6208 // . bitMapLock: if this is held, no other thread can access or update | |
| 6209 // | |
| 6210 | |
| 6211 // Note that we need to hold the freelistLock if we use | |
| 6212 // block iterate below; else the iterator might go awry if | |
| 6213 // a mutator (or promotion) causes block contents to change | |
| 6214 // (for instance if the allocator divvies up a block). | |
| 6215 // If we hold the free list lock, for all practical purposes | |
| 6216 // young generation GC's can't occur (they'll usually need to | |
| 6217 // promote), so we might as well prevent all young generation | |
| 6218 // GC's while we do a sweeping step. For the same reason, we might | |
| 6219 // as well take the bit map lock for the entire duration | |
| 6220 | |
| 6221 // check that we hold the requisite locks | |
| 6222 assert(have_cms_token(), "Should hold cms token"); | |
| 6223 assert( (asynch && ConcurrentMarkSweepThread::cms_thread_has_cms_token()) | |
| 6224 || (!asynch && ConcurrentMarkSweepThread::vm_thread_has_cms_token()), | |
| 6225 "Should possess CMS token to sweep"); | |
| 6226 assert_lock_strong(gen->freelistLock()); | |
| 6227 assert_lock_strong(bitMapLock()); | |
| 6228 | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6229 assert(!_inter_sweep_timer.is_active(), "Was switched off in an outer context"); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6230 assert(_intra_sweep_timer.is_active(), "Was switched on in an outer context"); |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6231 gen->cmsSpace()->beginSweepFLCensus((float)(_inter_sweep_timer.seconds()), |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6232 _inter_sweep_estimate.padded_average(), |
|
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6233 _intra_sweep_estimate.padded_average()); |
| 0 | 6234 gen->setNearLargestChunk(); |
| 6235 | |
| 6236 { | |
| 6237 SweepClosure sweepClosure(this, gen, &_markBitMap, | |
| 6238 CMSYield && asynch); | |
| 6239 gen->cmsSpace()->blk_iterate_careful(&sweepClosure); | |
| 6240 // We need to free-up/coalesce garbage/blocks from a | |
| 6241 // co-terminal free run. This is done in the SweepClosure | |
| 6242 // destructor; so, do not remove this scope, else the | |
| 6243 // end-of-sweep-census below will be off by a little bit. | |
| 6244 } | |
| 6245 gen->cmsSpace()->sweep_completed(); | |
|
1145
e018e6884bd8
6631166: CMS: better heuristics when combatting fragmentation
ysr
parents:
1085
diff
changeset
|
6246 gen->cmsSpace()->endSweepFLCensus(sweep_count()); |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6247 if (should_unload_classes()) { // unloaded classes this cycle, |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6248 _concurrent_cycles_since_last_unload = 0; // ... reset count |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6249 } else { // did not unload classes, |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6250 _concurrent_cycles_since_last_unload++; // ... increment count |
|
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
6251 } |
| 0 | 6252 } |
| 6253 | |
| 6254 // Reset CMS data structures (for now just the marking bit map) | |
| 6255 // preparatory for the next cycle. | |
| 6256 void CMSCollector::reset(bool asynch) { | |
| 6257 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 6258 CMSAdaptiveSizePolicy* sp = size_policy(); | |
| 6259 AdaptiveSizePolicyOutput(sp, gch->total_collections()); | |
| 6260 if (asynch) { | |
| 6261 CMSTokenSyncWithLocks ts(true, bitMapLock()); | |
| 6262 | |
| 6263 // If the state is not "Resetting", the foreground thread | |
| 6264 // has done a collection and the resetting. | |
| 6265 if (_collectorState != Resetting) { | |
| 6266 assert(_collectorState == Idling, "The state should only change" | |
| 6267 " because the foreground collector has finished the collection"); | |
| 6268 return; | |
| 6269 } | |
| 6270 | |
| 6271 // Clear the mark bitmap (no grey objects to start with) | |
| 6272 // for the next cycle. | |
| 6273 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 6274 CMSPhaseAccounting cmspa(this, "reset", !PrintGCDetails); | |
| 6275 | |
| 6276 HeapWord* curAddr = _markBitMap.startWord(); | |
| 6277 while (curAddr < _markBitMap.endWord()) { | |
| 6278 size_t remaining = pointer_delta(_markBitMap.endWord(), curAddr); | |
| 6279 MemRegion chunk(curAddr, MIN2(CMSBitMapYieldQuantum, remaining)); | |
| 6280 _markBitMap.clear_large_range(chunk); | |
| 6281 if (ConcurrentMarkSweepThread::should_yield() && | |
| 6282 !foregroundGCIsActive() && | |
| 6283 CMSYield) { | |
| 6284 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 6285 "CMS thread should hold CMS token"); | |
| 6286 assert_lock_strong(bitMapLock()); | |
| 6287 bitMapLock()->unlock(); | |
| 6288 ConcurrentMarkSweepThread::desynchronize(true); | |
| 6289 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 6290 stopTimer(); | |
| 6291 if (PrintCMSStatistics != 0) { | |
| 6292 incrementYields(); | |
| 6293 } | |
| 6294 icms_wait(); | |
| 6295 | |
| 6296 // See the comment in coordinator_yield() | |
| 6297 for (unsigned i = 0; i < CMSYieldSleepCount && | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6298 ConcurrentMarkSweepThread::should_yield() && |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6299 !CMSCollector::foregroundGCIsActive(); ++i) { |
| 0 | 6300 os::sleep(Thread::current(), 1, false); |
| 6301 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 6302 } | |
| 6303 | |
| 6304 ConcurrentMarkSweepThread::synchronize(true); | |
| 6305 bitMapLock()->lock_without_safepoint_check(); | |
| 6306 startTimer(); | |
| 6307 } | |
| 6308 curAddr = chunk.end(); | |
| 6309 } | |
|
1387
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
6310 // A successful mostly concurrent collection has been done. |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
6311 // Because only the full (i.e., concurrent mode failure) collections |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
6312 // are being measured for gc overhead limits, clean the "near" flag |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
6313 // and count. |
|
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
1289
diff
changeset
|
6314 sp->reset_gc_overhead_limit_count(); |
| 0 | 6315 _collectorState = Idling; |
| 6316 } else { | |
| 6317 // already have the lock | |
| 6318 assert(_collectorState == Resetting, "just checking"); | |
| 6319 assert_lock_strong(bitMapLock()); | |
| 6320 _markBitMap.clear_all(); | |
| 6321 _collectorState = Idling; | |
| 6322 } | |
| 6323 | |
| 6324 // Stop incremental mode after a cycle completes, so that any future cycles | |
| 6325 // are triggered by allocation. | |
| 6326 stop_icms(); | |
| 6327 | |
| 6328 NOT_PRODUCT( | |
| 6329 if (RotateCMSCollectionTypes) { | |
| 6330 _cmsGen->rotate_debug_collection_type(); | |
| 6331 } | |
| 6332 ) | |
| 6333 } | |
| 6334 | |
| 6335 void CMSCollector::do_CMS_operation(CMS_op_type op) { | |
| 6336 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
| 6337 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 6338 TraceTime t("GC", PrintGC, !PrintGCDetails, gclog_or_tty); | |
| 6339 TraceCollectorStats tcs(counters()); | |
| 6340 | |
| 6341 switch (op) { | |
| 6342 case CMS_op_checkpointRootsInitial: { | |
|
2125
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1994
diff
changeset
|
6343 SvcGCMarker sgcm(SvcGCMarker::OTHER); |
| 0 | 6344 checkpointRootsInitial(true); // asynch |
| 6345 if (PrintGC) { | |
| 6346 _cmsGen->printOccupancy("initial-mark"); | |
| 6347 } | |
| 6348 break; | |
| 6349 } | |
| 6350 case CMS_op_checkpointRootsFinal: { | |
|
2125
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1994
diff
changeset
|
6351 SvcGCMarker sgcm(SvcGCMarker::OTHER); |
| 0 | 6352 checkpointRootsFinal(true, // asynch |
| 6353 false, // !clear_all_soft_refs | |
| 6354 false); // !init_mark_was_synchronous | |
| 6355 if (PrintGC) { | |
| 6356 _cmsGen->printOccupancy("remark"); | |
| 6357 } | |
| 6358 break; | |
| 6359 } | |
| 6360 default: | |
| 6361 fatal("No such CMS_op"); | |
| 6362 } | |
| 6363 } | |
| 6364 | |
| 6365 #ifndef PRODUCT | |
| 6366 size_t const CMSCollector::skip_header_HeapWords() { | |
| 6367 return FreeChunk::header_size(); | |
| 6368 } | |
| 6369 | |
| 6370 // Try and collect here conditions that should hold when | |
| 6371 // CMS thread is exiting. The idea is that the foreground GC | |
| 6372 // thread should not be blocked if it wants to terminate | |
| 6373 // the CMS thread and yet continue to run the VM for a while | |
| 6374 // after that. | |
| 6375 void CMSCollector::verify_ok_to_terminate() const { | |
| 6376 assert(Thread::current()->is_ConcurrentGC_thread(), | |
| 6377 "should be called by CMS thread"); | |
| 6378 assert(!_foregroundGCShouldWait, "should be false"); | |
| 6379 // We could check here that all the various low-level locks | |
| 6380 // are not held by the CMS thread, but that is overkill; see | |
| 6381 // also CMSThread::verify_ok_to_terminate() where the CGC_lock | |
| 6382 // is checked. | |
| 6383 } | |
| 6384 #endif | |
| 6385 | |
| 6386 size_t CMSCollector::block_size_using_printezis_bits(HeapWord* addr) const { | |
|
453
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
6387 assert(_markBitMap.isMarked(addr) && _markBitMap.isMarked(addr + 1), |
|
c96030fff130
6684579: SoftReference processing can be made more efficient
ysr
parents:
452
diff
changeset
|
6388 "missing Printezis mark?"); |
| 0 | 6389 HeapWord* nextOneAddr = _markBitMap.getNextMarkedWordAddress(addr + 2); |
| 6390 size_t size = pointer_delta(nextOneAddr + 1, addr); | |
| 6391 assert(size == CompactibleFreeListSpace::adjustObjectSize(size), | |
| 6392 "alignment problem"); | |
| 6393 assert(size >= 3, "Necessary for Printezis marks to work"); | |
| 6394 return size; | |
| 6395 } | |
| 6396 | |
| 6397 // A variant of the above (block_size_using_printezis_bits()) except | |
| 6398 // that we return 0 if the P-bits are not yet set. | |
| 6399 size_t CMSCollector::block_size_if_printezis_bits(HeapWord* addr) const { | |
|
2226
c5a923563727
6912621: iCMS: Error: assert(_markBitMap.isMarked(addr + 1),"Missing Printezis bit?")
ysr
parents:
2177
diff
changeset
|
6400 if (_markBitMap.isMarked(addr + 1)) { |
|
c5a923563727
6912621: iCMS: Error: assert(_markBitMap.isMarked(addr + 1),"Missing Printezis bit?")
ysr
parents:
2177
diff
changeset
|
6401 assert(_markBitMap.isMarked(addr), "P-bit can be set only for marked objects"); |
| 0 | 6402 HeapWord* nextOneAddr = _markBitMap.getNextMarkedWordAddress(addr + 2); |
| 6403 size_t size = pointer_delta(nextOneAddr + 1, addr); | |
| 6404 assert(size == CompactibleFreeListSpace::adjustObjectSize(size), | |
| 6405 "alignment problem"); | |
| 6406 assert(size >= 3, "Necessary for Printezis marks to work"); | |
| 6407 return size; | |
|
2226
c5a923563727
6912621: iCMS: Error: assert(_markBitMap.isMarked(addr + 1),"Missing Printezis bit?")
ysr
parents:
2177
diff
changeset
|
6408 } |
|
c5a923563727
6912621: iCMS: Error: assert(_markBitMap.isMarked(addr + 1),"Missing Printezis bit?")
ysr
parents:
2177
diff
changeset
|
6409 return 0; |
| 0 | 6410 } |
| 6411 | |
| 6412 HeapWord* CMSCollector::next_card_start_after_block(HeapWord* addr) const { | |
| 6413 size_t sz = 0; | |
| 6414 oop p = (oop)addr; | |
| 187 | 6415 if (p->klass_or_null() != NULL && p->is_parsable()) { |
| 0 | 6416 sz = CompactibleFreeListSpace::adjustObjectSize(p->size()); |
| 6417 } else { | |
| 6418 sz = block_size_using_printezis_bits(addr); | |
| 6419 } | |
| 6420 assert(sz > 0, "size must be nonzero"); | |
| 6421 HeapWord* next_block = addr + sz; | |
| 6422 HeapWord* next_card = (HeapWord*)round_to((uintptr_t)next_block, | |
| 6423 CardTableModRefBS::card_size); | |
| 6424 assert(round_down((uintptr_t)addr, CardTableModRefBS::card_size) < | |
| 6425 round_down((uintptr_t)next_card, CardTableModRefBS::card_size), | |
| 6426 "must be different cards"); | |
| 6427 return next_card; | |
| 6428 } | |
| 6429 | |
| 6430 | |
| 6431 // CMS Bit Map Wrapper ///////////////////////////////////////// | |
| 6432 | |
| 6433 // Construct a CMS bit map infrastructure, but don't create the | |
| 6434 // bit vector itself. That is done by a separate call CMSBitMap::allocate() | |
| 6435 // further below. | |
| 6436 CMSBitMap::CMSBitMap(int shifter, int mutex_rank, const char* mutex_name): | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
6437 _bm(), |
| 0 | 6438 _shifter(shifter), |
| 6439 _lock(mutex_rank >= 0 ? new Mutex(mutex_rank, mutex_name, true) : NULL) | |
| 6440 { | |
| 6441 _bmStartWord = 0; | |
| 6442 _bmWordSize = 0; | |
| 6443 } | |
| 6444 | |
| 6445 bool CMSBitMap::allocate(MemRegion mr) { | |
| 6446 _bmStartWord = mr.start(); | |
| 6447 _bmWordSize = mr.word_size(); | |
| 6448 ReservedSpace brs(ReservedSpace::allocation_align_size_up( | |
| 6449 (_bmWordSize >> (_shifter + LogBitsPerByte)) + 1)); | |
| 6450 if (!brs.is_reserved()) { | |
| 6451 warning("CMS bit map allocation failure"); | |
| 6452 return false; | |
| 6453 } | |
| 6454 // For now we'll just commit all of the bit map up fromt. | |
| 6455 // Later on we'll try to be more parsimonious with swap. | |
| 6456 if (!_virtual_space.initialize(brs, brs.size())) { | |
| 6457 warning("CMS bit map backing store failure"); | |
| 6458 return false; | |
| 6459 } | |
| 6460 assert(_virtual_space.committed_size() == brs.size(), | |
| 6461 "didn't reserve backing store for all of CMS bit map?"); | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
6462 _bm.set_map((BitMap::bm_word_t*)_virtual_space.low()); |
| 0 | 6463 assert(_virtual_space.committed_size() << (_shifter + LogBitsPerByte) >= |
| 6464 _bmWordSize, "inconsistency in bit map sizing"); | |
| 6465 _bm.set_size(_bmWordSize >> _shifter); | |
| 6466 | |
| 6467 // bm.clear(); // can we rely on getting zero'd memory? verify below | |
| 6468 assert(isAllClear(), | |
| 6469 "Expected zero'd memory from ReservedSpace constructor"); | |
| 6470 assert(_bm.size() == heapWordDiffToOffsetDiff(sizeInWords()), | |
| 6471 "consistency check"); | |
| 6472 return true; | |
| 6473 } | |
| 6474 | |
| 6475 void CMSBitMap::dirty_range_iterate_clear(MemRegion mr, MemRegionClosure* cl) { | |
| 6476 HeapWord *next_addr, *end_addr, *last_addr; | |
| 6477 assert_locked(); | |
| 6478 assert(covers(mr), "out-of-range error"); | |
| 6479 // XXX assert that start and end are appropriately aligned | |
| 6480 for (next_addr = mr.start(), end_addr = mr.end(); | |
| 6481 next_addr < end_addr; next_addr = last_addr) { | |
| 6482 MemRegion dirty_region = getAndClearMarkedRegion(next_addr, end_addr); | |
| 6483 last_addr = dirty_region.end(); | |
| 6484 if (!dirty_region.is_empty()) { | |
| 6485 cl->do_MemRegion(dirty_region); | |
| 6486 } else { | |
| 6487 assert(last_addr == end_addr, "program logic"); | |
| 6488 return; | |
| 6489 } | |
| 6490 } | |
| 6491 } | |
| 6492 | |
| 6493 #ifndef PRODUCT | |
| 6494 void CMSBitMap::assert_locked() const { | |
| 6495 CMSLockVerifier::assert_locked(lock()); | |
| 6496 } | |
| 6497 | |
| 6498 bool CMSBitMap::covers(MemRegion mr) const { | |
| 6499 // assert(_bm.map() == _virtual_space.low(), "map inconsistency"); | |
| 6500 assert((size_t)_bm.size() == (_bmWordSize >> _shifter), | |
| 6501 "size inconsistency"); | |
| 6502 return (mr.start() >= _bmStartWord) && | |
| 6503 (mr.end() <= endWord()); | |
| 6504 } | |
| 6505 | |
| 6506 bool CMSBitMap::covers(HeapWord* start, size_t size) const { | |
| 6507 return (start >= _bmStartWord && (start + size) <= endWord()); | |
| 6508 } | |
| 6509 | |
| 6510 void CMSBitMap::verifyNoOneBitsInRange(HeapWord* left, HeapWord* right) { | |
| 6511 // verify that there are no 1 bits in the interval [left, right) | |
| 6512 FalseBitMapClosure falseBitMapClosure; | |
| 6513 iterate(&falseBitMapClosure, left, right); | |
| 6514 } | |
| 6515 | |
| 6516 void CMSBitMap::region_invariant(MemRegion mr) | |
| 6517 { | |
| 6518 assert_locked(); | |
| 6519 // mr = mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 6520 assert(!mr.is_empty(), "unexpected empty region"); | |
| 6521 assert(covers(mr), "mr should be covered by bit map"); | |
| 6522 // convert address range into offset range | |
| 6523 size_t start_ofs = heapWordToOffset(mr.start()); | |
| 6524 // Make sure that end() is appropriately aligned | |
| 6525 assert(mr.end() == (HeapWord*)round_to((intptr_t)mr.end(), | |
| 6526 (1 << (_shifter+LogHeapWordSize))), | |
| 6527 "Misaligned mr.end()"); | |
| 6528 size_t end_ofs = heapWordToOffset(mr.end()); | |
| 6529 assert(end_ofs > start_ofs, "Should mark at least one bit"); | |
| 6530 } | |
| 6531 | |
| 6532 #endif | |
| 6533 | |
| 6534 bool CMSMarkStack::allocate(size_t size) { | |
| 6535 // allocate a stack of the requisite depth | |
| 6536 ReservedSpace rs(ReservedSpace::allocation_align_size_up( | |
| 6537 size * sizeof(oop))); | |
| 6538 if (!rs.is_reserved()) { | |
| 6539 warning("CMSMarkStack allocation failure"); | |
| 6540 return false; | |
| 6541 } | |
| 6542 if (!_virtual_space.initialize(rs, rs.size())) { | |
| 6543 warning("CMSMarkStack backing store failure"); | |
| 6544 return false; | |
| 6545 } | |
| 6546 assert(_virtual_space.committed_size() == rs.size(), | |
| 6547 "didn't reserve backing store for all of CMS stack?"); | |
| 6548 _base = (oop*)(_virtual_space.low()); | |
| 6549 _index = 0; | |
| 6550 _capacity = size; | |
| 6551 NOT_PRODUCT(_max_depth = 0); | |
| 6552 return true; | |
| 6553 } | |
| 6554 | |
| 6555 // XXX FIX ME !!! In the MT case we come in here holding a | |
| 6556 // leaf lock. For printing we need to take a further lock | |
| 6557 // which has lower rank. We need to recallibrate the two | |
| 6558 // lock-ranks involved in order to be able to rpint the | |
| 6559 // messages below. (Or defer the printing to the caller. | |
| 6560 // For now we take the expedient path of just disabling the | |
| 6561 // messages for the problematic case.) | |
| 6562 void CMSMarkStack::expand() { | |
| 1284 | 6563 assert(_capacity <= MarkStackSizeMax, "stack bigger than permitted"); |
| 6564 if (_capacity == MarkStackSizeMax) { | |
| 0 | 6565 if (_hit_limit++ == 0 && !CMSConcurrentMTEnabled && PrintGCDetails) { |
| 6566 // We print a warning message only once per CMS cycle. | |
| 6567 gclog_or_tty->print_cr(" (benign) Hit CMSMarkStack max size limit"); | |
| 6568 } | |
| 6569 return; | |
| 6570 } | |
| 6571 // Double capacity if possible | |
| 1284 | 6572 size_t new_capacity = MIN2(_capacity*2, MarkStackSizeMax); |
| 0 | 6573 // Do not give up existing stack until we have managed to |
| 6574 // get the double capacity that we desired. | |
| 6575 ReservedSpace rs(ReservedSpace::allocation_align_size_up( | |
| 6576 new_capacity * sizeof(oop))); | |
| 6577 if (rs.is_reserved()) { | |
| 6578 // Release the backing store associated with old stack | |
| 6579 _virtual_space.release(); | |
| 6580 // Reinitialize virtual space for new stack | |
| 6581 if (!_virtual_space.initialize(rs, rs.size())) { | |
| 6582 fatal("Not enough swap for expanded marking stack"); | |
| 6583 } | |
| 6584 _base = (oop*)(_virtual_space.low()); | |
| 6585 _index = 0; | |
| 6586 _capacity = new_capacity; | |
| 6587 } else if (_failed_double++ == 0 && !CMSConcurrentMTEnabled && PrintGCDetails) { | |
| 6588 // Failed to double capacity, continue; | |
| 6589 // we print a detail message only once per CMS cycle. | |
| 6590 gclog_or_tty->print(" (benign) Failed to expand marking stack from "SIZE_FORMAT"K to " | |
| 6591 SIZE_FORMAT"K", | |
| 6592 _capacity / K, new_capacity / K); | |
| 6593 } | |
| 6594 } | |
| 6595 | |
| 6596 | |
| 6597 // Closures | |
| 6598 // XXX: there seems to be a lot of code duplication here; | |
| 6599 // should refactor and consolidate common code. | |
| 6600 | |
| 6601 // This closure is used to mark refs into the CMS generation in | |
| 6602 // the CMS bit map. Called at the first checkpoint. This closure | |
| 6603 // assumes that we do not need to re-mark dirty cards; if the CMS | |
| 6604 // generation on which this is used is not an oldest (modulo perm gen) | |
| 6605 // generation then this will lose younger_gen cards! | |
| 6606 | |
| 6607 MarkRefsIntoClosure::MarkRefsIntoClosure( | |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
6608 MemRegion span, CMSBitMap* bitMap): |
| 0 | 6609 _span(span), |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
6610 _bitMap(bitMap) |
| 0 | 6611 { |
| 6612 assert(_ref_processor == NULL, "deliberately left NULL"); | |
| 6613 assert(_bitMap->covers(_span), "_bitMap/_span mismatch"); | |
| 6614 } | |
| 6615 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6616 void MarkRefsIntoClosure::do_oop(oop obj) { |
| 0 | 6617 // if p points into _span, then mark corresponding bit in _markBitMap |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6618 assert(obj->is_oop(), "expected an oop"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6619 HeapWord* addr = (HeapWord*)obj; |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6620 if (_span.contains(addr)) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6621 // this should be made more efficient |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6622 _bitMap->mark(addr); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6623 } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6624 } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6625 |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6626 void MarkRefsIntoClosure::do_oop(oop* p) { MarkRefsIntoClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6627 void MarkRefsIntoClosure::do_oop(narrowOop* p) { MarkRefsIntoClosure::do_oop_work(p); } |
| 0 | 6628 |
| 6629 // A variant of the above, used for CMS marking verification. | |
| 6630 MarkRefsIntoVerifyClosure::MarkRefsIntoVerifyClosure( | |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
6631 MemRegion span, CMSBitMap* verification_bm, CMSBitMap* cms_bm): |
| 0 | 6632 _span(span), |
| 6633 _verification_bm(verification_bm), | |
|
994
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
6634 _cms_bm(cms_bm) |
|
753cf9794df9
6885169: merge of 4957990 and 6863023 causes conflict on do_nmethods
jrose
parents:
993
diff
changeset
|
6635 { |
| 0 | 6636 assert(_ref_processor == NULL, "deliberately left NULL"); |
| 6637 assert(_verification_bm->covers(_span), "_verification_bm/_span mismatch"); | |
| 6638 } | |
| 6639 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6640 void MarkRefsIntoVerifyClosure::do_oop(oop obj) { |
| 0 | 6641 // if p points into _span, then mark corresponding bit in _markBitMap |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6642 assert(obj->is_oop(), "expected an oop"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6643 HeapWord* addr = (HeapWord*)obj; |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6644 if (_span.contains(addr)) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6645 _verification_bm->mark(addr); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6646 if (!_cms_bm->isMarked(addr)) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6647 oop(addr)->print(); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6648 gclog_or_tty->print_cr(" (" INTPTR_FORMAT " should have been marked)", addr); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6649 fatal("... aborting"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6650 } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6651 } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6652 } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6653 |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6654 void MarkRefsIntoVerifyClosure::do_oop(oop* p) { MarkRefsIntoVerifyClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6655 void MarkRefsIntoVerifyClosure::do_oop(narrowOop* p) { MarkRefsIntoVerifyClosure::do_oop_work(p); } |
| 0 | 6656 |
| 6657 ////////////////////////////////////////////////// | |
| 6658 // MarkRefsIntoAndScanClosure | |
| 6659 ////////////////////////////////////////////////// | |
| 6660 | |
| 6661 MarkRefsIntoAndScanClosure::MarkRefsIntoAndScanClosure(MemRegion span, | |
| 6662 ReferenceProcessor* rp, | |
| 6663 CMSBitMap* bit_map, | |
| 6664 CMSBitMap* mod_union_table, | |
| 6665 CMSMarkStack* mark_stack, | |
| 6666 CMSMarkStack* revisit_stack, | |
| 6667 CMSCollector* collector, | |
| 6668 bool should_yield, | |
| 6669 bool concurrent_precleaning): | |
| 6670 _collector(collector), | |
| 6671 _span(span), | |
| 6672 _bit_map(bit_map), | |
| 6673 _mark_stack(mark_stack), | |
| 6674 _pushAndMarkClosure(collector, span, rp, bit_map, mod_union_table, | |
| 6675 mark_stack, revisit_stack, concurrent_precleaning), | |
| 6676 _yield(should_yield), | |
| 6677 _concurrent_precleaning(concurrent_precleaning), | |
| 6678 _freelistLock(NULL) | |
| 6679 { | |
| 6680 _ref_processor = rp; | |
| 6681 assert(_ref_processor != NULL, "_ref_processor shouldn't be NULL"); | |
| 6682 } | |
| 6683 | |
| 6684 // This closure is used to mark refs into the CMS generation at the | |
| 6685 // second (final) checkpoint, and to scan and transitively follow | |
| 6686 // the unmarked oops. It is also used during the concurrent precleaning | |
| 6687 // phase while scanning objects on dirty cards in the CMS generation. | |
| 6688 // The marks are made in the marking bit map and the marking stack is | |
| 6689 // used for keeping the (newly) grey objects during the scan. | |
| 6690 // The parallel version (Par_...) appears further below. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6691 void MarkRefsIntoAndScanClosure::do_oop(oop obj) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6692 if (obj != NULL) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6693 assert(obj->is_oop(), "expected an oop"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6694 HeapWord* addr = (HeapWord*)obj; |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6695 assert(_mark_stack->isEmpty(), "pre-condition (eager drainage)"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6696 assert(_collector->overflow_list_is_empty(), |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6697 "overflow list should be empty"); |
| 0 | 6698 if (_span.contains(addr) && |
| 6699 !_bit_map->isMarked(addr)) { | |
| 6700 // mark bit map (object is now grey) | |
| 6701 _bit_map->mark(addr); | |
| 6702 // push on marking stack (stack should be empty), and drain the | |
| 6703 // stack by applying this closure to the oops in the oops popped | |
| 6704 // from the stack (i.e. blacken the grey objects) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6705 bool res = _mark_stack->push(obj); |
| 0 | 6706 assert(res, "Should have space to push on empty stack"); |
| 6707 do { | |
| 6708 oop new_oop = _mark_stack->pop(); | |
| 6709 assert(new_oop != NULL && new_oop->is_oop(), "Expected an oop"); | |
| 6710 assert(new_oop->is_parsable(), "Found unparsable oop"); | |
| 6711 assert(_bit_map->isMarked((HeapWord*)new_oop), | |
| 6712 "only grey objects on this stack"); | |
| 6713 // iterate over the oops in this oop, marking and pushing | |
| 6714 // the ones in CMS heap (i.e. in _span). | |
| 6715 new_oop->oop_iterate(&_pushAndMarkClosure); | |
| 6716 // check if it's time to yield | |
| 6717 do_yield_check(); | |
| 6718 } while (!_mark_stack->isEmpty() || | |
| 6719 (!_concurrent_precleaning && take_from_overflow_list())); | |
| 6720 // if marking stack is empty, and we are not doing this | |
| 6721 // during precleaning, then check the overflow list | |
| 6722 } | |
| 6723 assert(_mark_stack->isEmpty(), "post-condition (eager drainage)"); | |
| 6724 assert(_collector->overflow_list_is_empty(), | |
| 6725 "overflow list was drained above"); | |
| 6726 // We could restore evacuated mark words, if any, used for | |
| 6727 // overflow list links here because the overflow list is | |
| 6728 // provably empty here. That would reduce the maximum | |
| 6729 // size requirements for preserved_{oop,mark}_stack. | |
| 6730 // But we'll just postpone it until we are all done | |
| 6731 // so we can just stream through. | |
| 6732 if (!_concurrent_precleaning && CMSOverflowEarlyRestoration) { | |
| 6733 _collector->restore_preserved_marks_if_any(); | |
| 6734 assert(_collector->no_preserved_marks(), "No preserved marks"); | |
| 6735 } | |
| 6736 assert(!CMSOverflowEarlyRestoration || _collector->no_preserved_marks(), | |
| 6737 "All preserved marks should have been restored above"); | |
| 6738 } | |
| 6739 } | |
| 6740 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6741 void MarkRefsIntoAndScanClosure::do_oop(oop* p) { MarkRefsIntoAndScanClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6742 void MarkRefsIntoAndScanClosure::do_oop(narrowOop* p) { MarkRefsIntoAndScanClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6743 |
| 0 | 6744 void MarkRefsIntoAndScanClosure::do_yield_work() { |
| 6745 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 6746 "CMS thread should hold CMS token"); | |
| 6747 assert_lock_strong(_freelistLock); | |
| 6748 assert_lock_strong(_bit_map->lock()); | |
| 6749 // relinquish the free_list_lock and bitMaplock() | |
| 935 | 6750 DEBUG_ONLY(RememberKlassesChecker mux(false);) |
| 0 | 6751 _bit_map->lock()->unlock(); |
| 6752 _freelistLock->unlock(); | |
| 6753 ConcurrentMarkSweepThread::desynchronize(true); | |
| 6754 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 6755 _collector->stopTimer(); | |
| 6756 GCPauseTimer p(_collector->size_policy()->concurrent_timer_ptr()); | |
| 6757 if (PrintCMSStatistics != 0) { | |
| 6758 _collector->incrementYields(); | |
| 6759 } | |
| 6760 _collector->icms_wait(); | |
| 6761 | |
| 6762 // See the comment in coordinator_yield() | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6763 for (unsigned i = 0; |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6764 i < CMSYieldSleepCount && |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6765 ConcurrentMarkSweepThread::should_yield() && |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6766 !CMSCollector::foregroundGCIsActive(); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6767 ++i) { |
| 0 | 6768 os::sleep(Thread::current(), 1, false); |
| 6769 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 6770 } | |
| 6771 | |
| 6772 ConcurrentMarkSweepThread::synchronize(true); | |
| 6773 _freelistLock->lock_without_safepoint_check(); | |
| 6774 _bit_map->lock()->lock_without_safepoint_check(); | |
| 6775 _collector->startTimer(); | |
| 6776 } | |
| 6777 | |
| 6778 /////////////////////////////////////////////////////////// | |
| 6779 // Par_MarkRefsIntoAndScanClosure: a parallel version of | |
| 6780 // MarkRefsIntoAndScanClosure | |
| 6781 /////////////////////////////////////////////////////////// | |
| 6782 Par_MarkRefsIntoAndScanClosure::Par_MarkRefsIntoAndScanClosure( | |
| 6783 CMSCollector* collector, MemRegion span, ReferenceProcessor* rp, | |
| 6784 CMSBitMap* bit_map, OopTaskQueue* work_queue, CMSMarkStack* revisit_stack): | |
| 6785 _span(span), | |
| 6786 _bit_map(bit_map), | |
| 6787 _work_queue(work_queue), | |
| 6788 _low_water_mark(MIN2((uint)(work_queue->max_elems()/4), | |
| 6789 (uint)(CMSWorkQueueDrainThreshold * ParallelGCThreads))), | |
| 6790 _par_pushAndMarkClosure(collector, span, rp, bit_map, work_queue, | |
| 6791 revisit_stack) | |
| 6792 { | |
| 6793 _ref_processor = rp; | |
| 6794 assert(_ref_processor != NULL, "_ref_processor shouldn't be NULL"); | |
| 6795 } | |
| 6796 | |
| 6797 // This closure is used to mark refs into the CMS generation at the | |
| 6798 // second (final) checkpoint, and to scan and transitively follow | |
| 6799 // the unmarked oops. The marks are made in the marking bit map and | |
| 6800 // the work_queue is used for keeping the (newly) grey objects during | |
| 6801 // the scan phase whence they are also available for stealing by parallel | |
| 6802 // threads. Since the marking bit map is shared, updates are | |
| 6803 // synchronized (via CAS). | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6804 void Par_MarkRefsIntoAndScanClosure::do_oop(oop obj) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6805 if (obj != NULL) { |
| 0 | 6806 // Ignore mark word because this could be an already marked oop |
| 6807 // that may be chained at the end of the overflow list. | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
6808 assert(obj->is_oop(true), "expected an oop"); |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6809 HeapWord* addr = (HeapWord*)obj; |
| 0 | 6810 if (_span.contains(addr) && |
| 6811 !_bit_map->isMarked(addr)) { | |
| 6812 // mark bit map (object will become grey): | |
| 6813 // It is possible for several threads to be | |
| 6814 // trying to "claim" this object concurrently; | |
| 6815 // the unique thread that succeeds in marking the | |
| 6816 // object first will do the subsequent push on | |
| 6817 // to the work queue (or overflow list). | |
| 6818 if (_bit_map->par_mark(addr)) { | |
| 6819 // push on work_queue (which may not be empty), and trim the | |
| 6820 // queue to an appropriate length by applying this closure to | |
| 6821 // the oops in the oops popped from the stack (i.e. blacken the | |
| 6822 // grey objects) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6823 bool res = _work_queue->push(obj); |
| 0 | 6824 assert(res, "Low water mark should be less than capacity?"); |
| 6825 trim_queue(_low_water_mark); | |
| 6826 } // Else, another thread claimed the object | |
| 6827 } | |
| 6828 } | |
| 6829 } | |
| 6830 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6831 void Par_MarkRefsIntoAndScanClosure::do_oop(oop* p) { Par_MarkRefsIntoAndScanClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6832 void Par_MarkRefsIntoAndScanClosure::do_oop(narrowOop* p) { Par_MarkRefsIntoAndScanClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6833 |
| 0 | 6834 // This closure is used to rescan the marked objects on the dirty cards |
| 6835 // in the mod union table and the card table proper. | |
| 6836 size_t ScanMarkedObjectsAgainCarefullyClosure::do_object_careful_m( | |
| 6837 oop p, MemRegion mr) { | |
| 6838 | |
| 6839 size_t size = 0; | |
| 6840 HeapWord* addr = (HeapWord*)p; | |
| 6841 DEBUG_ONLY(_collector->verify_work_stacks_empty();) | |
| 6842 assert(_span.contains(addr), "we are scanning the CMS generation"); | |
| 6843 // check if it's time to yield | |
| 6844 if (do_yield_check()) { | |
| 6845 // We yielded for some foreground stop-world work, | |
| 6846 // and we have been asked to abort this ongoing preclean cycle. | |
| 6847 return 0; | |
| 6848 } | |
| 6849 if (_bitMap->isMarked(addr)) { | |
| 6850 // it's marked; is it potentially uninitialized? | |
| 187 | 6851 if (p->klass_or_null() != NULL) { |
|
518
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
6852 // If is_conc_safe is false, the object may be undergoing |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
6853 // change by the VM outside a safepoint. Don't try to |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
6854 // scan it, but rather leave it for the remark phase. |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
6855 if (CMSPermGenPrecleaningEnabled && |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
6856 (!p->is_conc_safe() || !p->is_parsable())) { |
| 0 | 6857 // Signal precleaning to redirty the card since |
| 6858 // the klass pointer is already installed. | |
| 6859 assert(size == 0, "Initial value"); | |
| 6860 } else { | |
| 6861 assert(p->is_parsable(), "must be parsable."); | |
| 6862 // an initialized object; ignore mark word in verification below | |
| 6863 // since we are running concurrent with mutators | |
| 6864 assert(p->is_oop(true), "should be an oop"); | |
| 6865 if (p->is_objArray()) { | |
| 6866 // objArrays are precisely marked; restrict scanning | |
| 6867 // to dirty cards only. | |
| 187 | 6868 size = CompactibleFreeListSpace::adjustObjectSize( |
| 6869 p->oop_iterate(_scanningClosure, mr)); | |
| 0 | 6870 } else { |
| 6871 // A non-array may have been imprecisely marked; we need | |
| 6872 // to scan object in its entirety. | |
| 6873 size = CompactibleFreeListSpace::adjustObjectSize( | |
| 6874 p->oop_iterate(_scanningClosure)); | |
| 6875 } | |
| 6876 #ifdef DEBUG | |
| 6877 size_t direct_size = | |
| 6878 CompactibleFreeListSpace::adjustObjectSize(p->size()); | |
| 6879 assert(size == direct_size, "Inconsistency in size"); | |
| 6880 assert(size >= 3, "Necessary for Printezis marks to work"); | |
| 6881 if (!_bitMap->isMarked(addr+1)) { | |
| 6882 _bitMap->verifyNoOneBitsInRange(addr+2, addr+size); | |
| 6883 } else { | |
| 6884 _bitMap->verifyNoOneBitsInRange(addr+2, addr+size-1); | |
| 6885 assert(_bitMap->isMarked(addr+size-1), | |
| 6886 "inconsistent Printezis mark"); | |
| 6887 } | |
| 6888 #endif // DEBUG | |
| 6889 } | |
| 6890 } else { | |
| 6891 // an unitialized object | |
| 6892 assert(_bitMap->isMarked(addr+1), "missing Printezis mark?"); | |
| 6893 HeapWord* nextOneAddr = _bitMap->getNextMarkedWordAddress(addr + 2); | |
| 6894 size = pointer_delta(nextOneAddr + 1, addr); | |
| 6895 assert(size == CompactibleFreeListSpace::adjustObjectSize(size), | |
| 6896 "alignment problem"); | |
| 6897 // Note that pre-cleaning needn't redirty the card. OopDesc::set_klass() | |
| 6898 // will dirty the card when the klass pointer is installed in the | |
| 6899 // object (signalling the completion of initialization). | |
| 6900 } | |
| 6901 } else { | |
| 6902 // Either a not yet marked object or an uninitialized object | |
| 187 | 6903 if (p->klass_or_null() == NULL || !p->is_parsable()) { |
| 0 | 6904 // An uninitialized object, skip to the next card, since |
| 6905 // we may not be able to read its P-bits yet. | |
| 6906 assert(size == 0, "Initial value"); | |
| 6907 } else { | |
| 6908 // An object not (yet) reached by marking: we merely need to | |
| 6909 // compute its size so as to go look at the next block. | |
| 6910 assert(p->is_oop(true), "should be an oop"); | |
| 6911 size = CompactibleFreeListSpace::adjustObjectSize(p->size()); | |
| 6912 } | |
| 6913 } | |
| 6914 DEBUG_ONLY(_collector->verify_work_stacks_empty();) | |
| 6915 return size; | |
| 6916 } | |
| 6917 | |
| 6918 void ScanMarkedObjectsAgainCarefullyClosure::do_yield_work() { | |
| 6919 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 6920 "CMS thread should hold CMS token"); | |
| 6921 assert_lock_strong(_freelistLock); | |
| 6922 assert_lock_strong(_bitMap->lock()); | |
| 935 | 6923 DEBUG_ONLY(RememberKlassesChecker mux(false);) |
| 0 | 6924 // relinquish the free_list_lock and bitMaplock() |
| 6925 _bitMap->lock()->unlock(); | |
| 6926 _freelistLock->unlock(); | |
| 6927 ConcurrentMarkSweepThread::desynchronize(true); | |
| 6928 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 6929 _collector->stopTimer(); | |
| 6930 GCPauseTimer p(_collector->size_policy()->concurrent_timer_ptr()); | |
| 6931 if (PrintCMSStatistics != 0) { | |
| 6932 _collector->incrementYields(); | |
| 6933 } | |
| 6934 _collector->icms_wait(); | |
| 6935 | |
| 6936 // See the comment in coordinator_yield() | |
| 6937 for (unsigned i = 0; i < CMSYieldSleepCount && | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6938 ConcurrentMarkSweepThread::should_yield() && |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
6939 !CMSCollector::foregroundGCIsActive(); ++i) { |
| 0 | 6940 os::sleep(Thread::current(), 1, false); |
| 6941 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 6942 } | |
| 6943 | |
| 6944 ConcurrentMarkSweepThread::synchronize(true); | |
| 6945 _freelistLock->lock_without_safepoint_check(); | |
| 6946 _bitMap->lock()->lock_without_safepoint_check(); | |
| 6947 _collector->startTimer(); | |
| 6948 } | |
| 6949 | |
| 6950 | |
| 6951 ////////////////////////////////////////////////////////////////// | |
| 6952 // SurvivorSpacePrecleanClosure | |
| 6953 ////////////////////////////////////////////////////////////////// | |
| 6954 // This (single-threaded) closure is used to preclean the oops in | |
| 6955 // the survivor spaces. | |
| 6956 size_t SurvivorSpacePrecleanClosure::do_object_careful(oop p) { | |
| 6957 | |
| 6958 HeapWord* addr = (HeapWord*)p; | |
| 6959 DEBUG_ONLY(_collector->verify_work_stacks_empty();) | |
| 6960 assert(!_span.contains(addr), "we are scanning the survivor spaces"); | |
| 187 | 6961 assert(p->klass_or_null() != NULL, "object should be initializd"); |
| 0 | 6962 assert(p->is_parsable(), "must be parsable."); |
| 6963 // an initialized object; ignore mark word in verification below | |
| 6964 // since we are running concurrent with mutators | |
| 6965 assert(p->is_oop(true), "should be an oop"); | |
| 6966 // Note that we do not yield while we iterate over | |
| 6967 // the interior oops of p, pushing the relevant ones | |
| 6968 // on our marking stack. | |
| 6969 size_t size = p->oop_iterate(_scanning_closure); | |
| 6970 do_yield_check(); | |
| 6971 // Observe that below, we do not abandon the preclean | |
| 6972 // phase as soon as we should; rather we empty the | |
| 6973 // marking stack before returning. This is to satisfy | |
| 6974 // some existing assertions. In general, it may be a | |
| 6975 // good idea to abort immediately and complete the marking | |
| 6976 // from the grey objects at a later time. | |
| 6977 while (!_mark_stack->isEmpty()) { | |
| 6978 oop new_oop = _mark_stack->pop(); | |
| 6979 assert(new_oop != NULL && new_oop->is_oop(), "Expected an oop"); | |
| 6980 assert(new_oop->is_parsable(), "Found unparsable oop"); | |
| 6981 assert(_bit_map->isMarked((HeapWord*)new_oop), | |
| 6982 "only grey objects on this stack"); | |
| 6983 // iterate over the oops in this oop, marking and pushing | |
| 6984 // the ones in CMS heap (i.e. in _span). | |
| 6985 new_oop->oop_iterate(_scanning_closure); | |
| 6986 // check if it's time to yield | |
| 6987 do_yield_check(); | |
| 6988 } | |
| 6989 unsigned int after_count = | |
| 6990 GenCollectedHeap::heap()->total_collections(); | |
| 6991 bool abort = (_before_count != after_count) || | |
| 6992 _collector->should_abort_preclean(); | |
| 6993 return abort ? 0 : size; | |
| 6994 } | |
| 6995 | |
| 6996 void SurvivorSpacePrecleanClosure::do_yield_work() { | |
| 6997 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 6998 "CMS thread should hold CMS token"); | |
| 6999 assert_lock_strong(_bit_map->lock()); | |
| 935 | 7000 DEBUG_ONLY(RememberKlassesChecker smx(false);) |
| 0 | 7001 // Relinquish the bit map lock |
| 7002 _bit_map->lock()->unlock(); | |
| 7003 ConcurrentMarkSweepThread::desynchronize(true); | |
| 7004 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 7005 _collector->stopTimer(); | |
| 7006 GCPauseTimer p(_collector->size_policy()->concurrent_timer_ptr()); | |
| 7007 if (PrintCMSStatistics != 0) { | |
| 7008 _collector->incrementYields(); | |
| 7009 } | |
| 7010 _collector->icms_wait(); | |
| 7011 | |
| 7012 // See the comment in coordinator_yield() | |
| 7013 for (unsigned i = 0; i < CMSYieldSleepCount && | |
| 7014 ConcurrentMarkSweepThread::should_yield() && | |
| 7015 !CMSCollector::foregroundGCIsActive(); ++i) { | |
| 7016 os::sleep(Thread::current(), 1, false); | |
| 7017 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 7018 } | |
| 7019 | |
| 7020 ConcurrentMarkSweepThread::synchronize(true); | |
| 7021 _bit_map->lock()->lock_without_safepoint_check(); | |
| 7022 _collector->startTimer(); | |
| 7023 } | |
| 7024 | |
| 7025 // This closure is used to rescan the marked objects on the dirty cards | |
| 7026 // in the mod union table and the card table proper. In the parallel | |
| 7027 // case, although the bitMap is shared, we do a single read so the | |
| 7028 // isMarked() query is "safe". | |
| 7029 bool ScanMarkedObjectsAgainClosure::do_object_bm(oop p, MemRegion mr) { | |
| 7030 // Ignore mark word because we are running concurrent with mutators | |
| 7031 assert(p->is_oop_or_null(true), "expected an oop or null"); | |
| 7032 HeapWord* addr = (HeapWord*)p; | |
| 7033 assert(_span.contains(addr), "we are scanning the CMS generation"); | |
| 7034 bool is_obj_array = false; | |
| 7035 #ifdef DEBUG | |
| 7036 if (!_parallel) { | |
| 7037 assert(_mark_stack->isEmpty(), "pre-condition (eager drainage)"); | |
| 7038 assert(_collector->overflow_list_is_empty(), | |
| 7039 "overflow list should be empty"); | |
| 7040 | |
| 7041 } | |
| 7042 #endif // DEBUG | |
| 7043 if (_bit_map->isMarked(addr)) { | |
| 7044 // Obj arrays are precisely marked, non-arrays are not; | |
| 7045 // so we scan objArrays precisely and non-arrays in their | |
| 7046 // entirety. | |
| 7047 if (p->is_objArray()) { | |
| 7048 is_obj_array = true; | |
| 7049 if (_parallel) { | |
| 7050 p->oop_iterate(_par_scan_closure, mr); | |
| 7051 } else { | |
| 7052 p->oop_iterate(_scan_closure, mr); | |
| 7053 } | |
| 7054 } else { | |
| 7055 if (_parallel) { | |
| 7056 p->oop_iterate(_par_scan_closure); | |
| 7057 } else { | |
| 7058 p->oop_iterate(_scan_closure); | |
| 7059 } | |
| 7060 } | |
| 7061 } | |
| 7062 #ifdef DEBUG | |
| 7063 if (!_parallel) { | |
| 7064 assert(_mark_stack->isEmpty(), "post-condition (eager drainage)"); | |
| 7065 assert(_collector->overflow_list_is_empty(), | |
| 7066 "overflow list should be empty"); | |
| 7067 | |
| 7068 } | |
| 7069 #endif // DEBUG | |
| 7070 return is_obj_array; | |
| 7071 } | |
| 7072 | |
| 7073 MarkFromRootsClosure::MarkFromRootsClosure(CMSCollector* collector, | |
| 7074 MemRegion span, | |
| 7075 CMSBitMap* bitMap, CMSMarkStack* markStack, | |
| 7076 CMSMarkStack* revisitStack, | |
| 7077 bool should_yield, bool verifying): | |
| 7078 _collector(collector), | |
| 7079 _span(span), | |
| 7080 _bitMap(bitMap), | |
| 7081 _mut(&collector->_modUnionTable), | |
| 7082 _markStack(markStack), | |
| 7083 _revisitStack(revisitStack), | |
| 7084 _yield(should_yield), | |
| 7085 _skipBits(0) | |
| 7086 { | |
| 7087 assert(_markStack->isEmpty(), "stack should be empty"); | |
| 7088 _finger = _bitMap->startWord(); | |
| 7089 _threshold = _finger; | |
| 7090 assert(_collector->_restart_addr == NULL, "Sanity check"); | |
| 7091 assert(_span.contains(_finger), "Out of bounds _finger?"); | |
| 7092 DEBUG_ONLY(_verifying = verifying;) | |
| 7093 } | |
| 7094 | |
| 7095 void MarkFromRootsClosure::reset(HeapWord* addr) { | |
| 7096 assert(_markStack->isEmpty(), "would cause duplicates on stack"); | |
| 7097 assert(_span.contains(addr), "Out of bounds _finger?"); | |
| 7098 _finger = addr; | |
| 7099 _threshold = (HeapWord*)round_to( | |
| 7100 (intptr_t)_finger, CardTableModRefBS::card_size); | |
| 7101 } | |
| 7102 | |
| 7103 // Should revisit to see if this should be restructured for | |
| 7104 // greater efficiency. | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7105 bool MarkFromRootsClosure::do_bit(size_t offset) { |
| 0 | 7106 if (_skipBits > 0) { |
| 7107 _skipBits--; | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7108 return true; |
| 0 | 7109 } |
| 7110 // convert offset into a HeapWord* | |
| 7111 HeapWord* addr = _bitMap->startWord() + offset; | |
| 7112 assert(_bitMap->endWord() && addr < _bitMap->endWord(), | |
| 7113 "address out of range"); | |
| 7114 assert(_bitMap->isMarked(addr), "tautology"); | |
| 7115 if (_bitMap->isMarked(addr+1)) { | |
| 7116 // this is an allocated but not yet initialized object | |
| 7117 assert(_skipBits == 0, "tautology"); | |
| 7118 _skipBits = 2; // skip next two marked bits ("Printezis-marks") | |
| 7119 oop p = oop(addr); | |
| 187 | 7120 if (p->klass_or_null() == NULL || !p->is_parsable()) { |
| 0 | 7121 DEBUG_ONLY(if (!_verifying) {) |
| 7122 // We re-dirty the cards on which this object lies and increase | |
| 7123 // the _threshold so that we'll come back to scan this object | |
| 7124 // during the preclean or remark phase. (CMSCleanOnEnter) | |
| 7125 if (CMSCleanOnEnter) { | |
| 7126 size_t sz = _collector->block_size_using_printezis_bits(addr); | |
| 7127 HeapWord* end_card_addr = (HeapWord*)round_to( | |
| 7128 (intptr_t)(addr+sz), CardTableModRefBS::card_size); | |
|
283
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7129 MemRegion redirty_range = MemRegion(addr, end_card_addr); |
| 0 | 7130 assert(!redirty_range.is_empty(), "Arithmetical tautology"); |
| 7131 // Bump _threshold to end_card_addr; note that | |
| 7132 // _threshold cannot possibly exceed end_card_addr, anyhow. | |
| 7133 // This prevents future clearing of the card as the scan proceeds | |
| 7134 // to the right. | |
| 7135 assert(_threshold <= end_card_addr, | |
| 7136 "Because we are just scanning into this object"); | |
| 7137 if (_threshold < end_card_addr) { | |
| 7138 _threshold = end_card_addr; | |
| 7139 } | |
| 187 | 7140 if (p->klass_or_null() != NULL) { |
| 0 | 7141 // Redirty the range of cards... |
| 7142 _mut->mark_range(redirty_range); | |
| 7143 } // ...else the setting of klass will dirty the card anyway. | |
| 7144 } | |
| 7145 DEBUG_ONLY(}) | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7146 return true; |
| 0 | 7147 } |
| 7148 } | |
| 7149 scanOopsInOop(addr); | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7150 return true; |
| 0 | 7151 } |
| 7152 | |
| 7153 // We take a break if we've been at this for a while, | |
| 7154 // so as to avoid monopolizing the locks involved. | |
| 7155 void MarkFromRootsClosure::do_yield_work() { | |
| 7156 // First give up the locks, then yield, then re-lock | |
| 7157 // We should probably use a constructor/destructor idiom to | |
| 7158 // do this unlock/lock or modify the MutexUnlocker class to | |
| 7159 // serve our purpose. XXX | |
| 7160 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 7161 "CMS thread should hold CMS token"); | |
| 7162 assert_lock_strong(_bitMap->lock()); | |
| 935 | 7163 DEBUG_ONLY(RememberKlassesChecker mux(false);) |
| 0 | 7164 _bitMap->lock()->unlock(); |
| 7165 ConcurrentMarkSweepThread::desynchronize(true); | |
| 7166 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 7167 _collector->stopTimer(); | |
| 7168 GCPauseTimer p(_collector->size_policy()->concurrent_timer_ptr()); | |
| 7169 if (PrintCMSStatistics != 0) { | |
| 7170 _collector->incrementYields(); | |
| 7171 } | |
| 7172 _collector->icms_wait(); | |
| 7173 | |
| 7174 // See the comment in coordinator_yield() | |
| 7175 for (unsigned i = 0; i < CMSYieldSleepCount && | |
| 7176 ConcurrentMarkSweepThread::should_yield() && | |
| 7177 !CMSCollector::foregroundGCIsActive(); ++i) { | |
| 7178 os::sleep(Thread::current(), 1, false); | |
| 7179 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 7180 } | |
| 7181 | |
| 7182 ConcurrentMarkSweepThread::synchronize(true); | |
| 7183 _bitMap->lock()->lock_without_safepoint_check(); | |
| 7184 _collector->startTimer(); | |
| 7185 } | |
| 7186 | |
| 7187 void MarkFromRootsClosure::scanOopsInOop(HeapWord* ptr) { | |
| 7188 assert(_bitMap->isMarked(ptr), "expected bit to be set"); | |
| 7189 assert(_markStack->isEmpty(), | |
| 7190 "should drain stack to limit stack usage"); | |
| 7191 // convert ptr to an oop preparatory to scanning | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7192 oop obj = oop(ptr); |
| 0 | 7193 // Ignore mark word in verification below, since we |
| 7194 // may be running concurrent with mutators. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7195 assert(obj->is_oop(true), "should be an oop"); |
| 0 | 7196 assert(_finger <= ptr, "_finger runneth ahead"); |
| 7197 // advance the finger to right end of this object | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7198 _finger = ptr + obj->size(); |
| 0 | 7199 assert(_finger > ptr, "we just incremented it above"); |
| 7200 // On large heaps, it may take us some time to get through | |
| 7201 // the marking phase (especially if running iCMS). During | |
| 7202 // this time it's possible that a lot of mutations have | |
| 7203 // accumulated in the card table and the mod union table -- | |
| 7204 // these mutation records are redundant until we have | |
| 7205 // actually traced into the corresponding card. | |
| 7206 // Here, we check whether advancing the finger would make | |
| 7207 // us cross into a new card, and if so clear corresponding | |
| 7208 // cards in the MUT (preclean them in the card-table in the | |
| 7209 // future). | |
| 7210 | |
| 7211 DEBUG_ONLY(if (!_verifying) {) | |
| 7212 // The clean-on-enter optimization is disabled by default, | |
| 7213 // until we fix 6178663. | |
| 7214 if (CMSCleanOnEnter && (_finger > _threshold)) { | |
| 7215 // [_threshold, _finger) represents the interval | |
| 7216 // of cards to be cleared in MUT (or precleaned in card table). | |
| 7217 // The set of cards to be cleared is all those that overlap | |
| 7218 // with the interval [_threshold, _finger); note that | |
| 7219 // _threshold is always kept card-aligned but _finger isn't | |
| 7220 // always card-aligned. | |
| 7221 HeapWord* old_threshold = _threshold; | |
| 7222 assert(old_threshold == (HeapWord*)round_to( | |
| 7223 (intptr_t)old_threshold, CardTableModRefBS::card_size), | |
| 7224 "_threshold should always be card-aligned"); | |
| 7225 _threshold = (HeapWord*)round_to( | |
| 7226 (intptr_t)_finger, CardTableModRefBS::card_size); | |
| 7227 MemRegion mr(old_threshold, _threshold); | |
| 7228 assert(!mr.is_empty(), "Control point invariant"); | |
| 7229 assert(_span.contains(mr), "Should clear within span"); | |
| 7230 // XXX When _finger crosses from old gen into perm gen | |
| 7231 // we may be doing unnecessary cleaning; do better in the | |
| 7232 // future by detecting that condition and clearing fewer | |
| 7233 // MUT/CT entries. | |
| 7234 _mut->clear_range(mr); | |
| 7235 } | |
| 7236 DEBUG_ONLY(}) | |
| 7237 // Note: the finger doesn't advance while we drain | |
| 7238 // the stack below. | |
| 7239 PushOrMarkClosure pushOrMarkClosure(_collector, | |
| 7240 _span, _bitMap, _markStack, | |
| 7241 _revisitStack, | |
| 7242 _finger, this); | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7243 bool res = _markStack->push(obj); |
| 0 | 7244 assert(res, "Empty non-zero size stack should have space for single push"); |
| 7245 while (!_markStack->isEmpty()) { | |
| 7246 oop new_oop = _markStack->pop(); | |
| 7247 // Skip verifying header mark word below because we are | |
| 7248 // running concurrent with mutators. | |
| 7249 assert(new_oop->is_oop(true), "Oops! expected to pop an oop"); | |
| 7250 // now scan this oop's oops | |
| 7251 new_oop->oop_iterate(&pushOrMarkClosure); | |
| 7252 do_yield_check(); | |
| 7253 } | |
| 7254 assert(_markStack->isEmpty(), "tautology, emphasizing post-condition"); | |
| 7255 } | |
| 7256 | |
| 7257 Par_MarkFromRootsClosure::Par_MarkFromRootsClosure(CMSConcMarkingTask* task, | |
| 7258 CMSCollector* collector, MemRegion span, | |
| 7259 CMSBitMap* bit_map, | |
| 7260 OopTaskQueue* work_queue, | |
| 7261 CMSMarkStack* overflow_stack, | |
| 7262 CMSMarkStack* revisit_stack, | |
| 7263 bool should_yield): | |
| 7264 _collector(collector), | |
| 7265 _whole_span(collector->_span), | |
| 7266 _span(span), | |
| 7267 _bit_map(bit_map), | |
| 7268 _mut(&collector->_modUnionTable), | |
| 7269 _work_queue(work_queue), | |
| 7270 _overflow_stack(overflow_stack), | |
| 7271 _revisit_stack(revisit_stack), | |
| 7272 _yield(should_yield), | |
| 7273 _skip_bits(0), | |
| 7274 _task(task) | |
| 7275 { | |
| 7276 assert(_work_queue->size() == 0, "work_queue should be empty"); | |
| 7277 _finger = span.start(); | |
| 7278 _threshold = _finger; // XXX Defer clear-on-enter optimization for now | |
| 7279 assert(_span.contains(_finger), "Out of bounds _finger?"); | |
| 7280 } | |
| 7281 | |
| 7282 // Should revisit to see if this should be restructured for | |
| 7283 // greater efficiency. | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7284 bool Par_MarkFromRootsClosure::do_bit(size_t offset) { |
| 0 | 7285 if (_skip_bits > 0) { |
| 7286 _skip_bits--; | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7287 return true; |
| 0 | 7288 } |
| 7289 // convert offset into a HeapWord* | |
| 7290 HeapWord* addr = _bit_map->startWord() + offset; | |
| 7291 assert(_bit_map->endWord() && addr < _bit_map->endWord(), | |
| 7292 "address out of range"); | |
| 7293 assert(_bit_map->isMarked(addr), "tautology"); | |
| 7294 if (_bit_map->isMarked(addr+1)) { | |
| 7295 // this is an allocated object that might not yet be initialized | |
| 7296 assert(_skip_bits == 0, "tautology"); | |
| 7297 _skip_bits = 2; // skip next two marked bits ("Printezis-marks") | |
| 7298 oop p = oop(addr); | |
| 187 | 7299 if (p->klass_or_null() == NULL || !p->is_parsable()) { |
| 0 | 7300 // in the case of Clean-on-Enter optimization, redirty card |
| 7301 // and avoid clearing card by increasing the threshold. | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7302 return true; |
| 0 | 7303 } |
| 7304 } | |
| 7305 scan_oops_in_oop(addr); | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7306 return true; |
| 0 | 7307 } |
| 7308 | |
| 7309 void Par_MarkFromRootsClosure::scan_oops_in_oop(HeapWord* ptr) { | |
| 7310 assert(_bit_map->isMarked(ptr), "expected bit to be set"); | |
| 7311 // Should we assert that our work queue is empty or | |
| 7312 // below some drain limit? | |
| 7313 assert(_work_queue->size() == 0, | |
| 7314 "should drain stack to limit stack usage"); | |
| 7315 // convert ptr to an oop preparatory to scanning | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7316 oop obj = oop(ptr); |
| 0 | 7317 // Ignore mark word in verification below, since we |
| 7318 // may be running concurrent with mutators. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7319 assert(obj->is_oop(true), "should be an oop"); |
| 0 | 7320 assert(_finger <= ptr, "_finger runneth ahead"); |
| 7321 // advance the finger to right end of this object | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7322 _finger = ptr + obj->size(); |
| 0 | 7323 assert(_finger > ptr, "we just incremented it above"); |
| 7324 // On large heaps, it may take us some time to get through | |
| 7325 // the marking phase (especially if running iCMS). During | |
| 7326 // this time it's possible that a lot of mutations have | |
| 7327 // accumulated in the card table and the mod union table -- | |
| 7328 // these mutation records are redundant until we have | |
| 7329 // actually traced into the corresponding card. | |
| 7330 // Here, we check whether advancing the finger would make | |
| 7331 // us cross into a new card, and if so clear corresponding | |
| 7332 // cards in the MUT (preclean them in the card-table in the | |
| 7333 // future). | |
| 7334 | |
| 7335 // The clean-on-enter optimization is disabled by default, | |
| 7336 // until we fix 6178663. | |
| 7337 if (CMSCleanOnEnter && (_finger > _threshold)) { | |
| 7338 // [_threshold, _finger) represents the interval | |
| 7339 // of cards to be cleared in MUT (or precleaned in card table). | |
| 7340 // The set of cards to be cleared is all those that overlap | |
| 7341 // with the interval [_threshold, _finger); note that | |
| 7342 // _threshold is always kept card-aligned but _finger isn't | |
| 7343 // always card-aligned. | |
| 7344 HeapWord* old_threshold = _threshold; | |
| 7345 assert(old_threshold == (HeapWord*)round_to( | |
| 7346 (intptr_t)old_threshold, CardTableModRefBS::card_size), | |
| 7347 "_threshold should always be card-aligned"); | |
| 7348 _threshold = (HeapWord*)round_to( | |
| 7349 (intptr_t)_finger, CardTableModRefBS::card_size); | |
| 7350 MemRegion mr(old_threshold, _threshold); | |
| 7351 assert(!mr.is_empty(), "Control point invariant"); | |
| 7352 assert(_span.contains(mr), "Should clear within span"); // _whole_span ?? | |
| 7353 // XXX When _finger crosses from old gen into perm gen | |
| 7354 // we may be doing unnecessary cleaning; do better in the | |
| 7355 // future by detecting that condition and clearing fewer | |
| 7356 // MUT/CT entries. | |
| 7357 _mut->clear_range(mr); | |
| 7358 } | |
| 7359 | |
| 7360 // Note: the local finger doesn't advance while we drain | |
| 7361 // the stack below, but the global finger sure can and will. | |
| 7362 HeapWord** gfa = _task->global_finger_addr(); | |
| 7363 Par_PushOrMarkClosure pushOrMarkClosure(_collector, | |
| 7364 _span, _bit_map, | |
| 7365 _work_queue, | |
| 7366 _overflow_stack, | |
| 7367 _revisit_stack, | |
| 7368 _finger, | |
| 7369 gfa, this); | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7370 bool res = _work_queue->push(obj); // overflow could occur here |
| 0 | 7371 assert(res, "Will hold once we use workqueues"); |
| 7372 while (true) { | |
| 7373 oop new_oop; | |
| 7374 if (!_work_queue->pop_local(new_oop)) { | |
| 7375 // We emptied our work_queue; check if there's stuff that can | |
| 7376 // be gotten from the overflow stack. | |
| 7377 if (CMSConcMarkingTask::get_work_from_overflow_stack( | |
| 7378 _overflow_stack, _work_queue)) { | |
| 7379 do_yield_check(); | |
| 7380 continue; | |
| 7381 } else { // done | |
| 7382 break; | |
| 7383 } | |
| 7384 } | |
| 7385 // Skip verifying header mark word below because we are | |
| 7386 // running concurrent with mutators. | |
| 7387 assert(new_oop->is_oop(true), "Oops! expected to pop an oop"); | |
| 7388 // now scan this oop's oops | |
| 7389 new_oop->oop_iterate(&pushOrMarkClosure); | |
| 7390 do_yield_check(); | |
| 7391 } | |
| 7392 assert(_work_queue->size() == 0, "tautology, emphasizing post-condition"); | |
| 7393 } | |
| 7394 | |
| 7395 // Yield in response to a request from VM Thread or | |
| 7396 // from mutators. | |
| 7397 void Par_MarkFromRootsClosure::do_yield_work() { | |
| 7398 assert(_task != NULL, "sanity"); | |
| 7399 _task->yield(); | |
| 7400 } | |
| 7401 | |
| 7402 // A variant of the above used for verifying CMS marking work. | |
| 7403 MarkFromRootsVerifyClosure::MarkFromRootsVerifyClosure(CMSCollector* collector, | |
| 7404 MemRegion span, | |
| 7405 CMSBitMap* verification_bm, CMSBitMap* cms_bm, | |
| 7406 CMSMarkStack* mark_stack): | |
| 7407 _collector(collector), | |
| 7408 _span(span), | |
| 7409 _verification_bm(verification_bm), | |
| 7410 _cms_bm(cms_bm), | |
| 7411 _mark_stack(mark_stack), | |
| 7412 _pam_verify_closure(collector, span, verification_bm, cms_bm, | |
| 7413 mark_stack) | |
| 7414 { | |
| 7415 assert(_mark_stack->isEmpty(), "stack should be empty"); | |
| 7416 _finger = _verification_bm->startWord(); | |
| 7417 assert(_collector->_restart_addr == NULL, "Sanity check"); | |
| 7418 assert(_span.contains(_finger), "Out of bounds _finger?"); | |
| 7419 } | |
| 7420 | |
| 7421 void MarkFromRootsVerifyClosure::reset(HeapWord* addr) { | |
| 7422 assert(_mark_stack->isEmpty(), "would cause duplicates on stack"); | |
| 7423 assert(_span.contains(addr), "Out of bounds _finger?"); | |
| 7424 _finger = addr; | |
| 7425 } | |
| 7426 | |
| 7427 // Should revisit to see if this should be restructured for | |
| 7428 // greater efficiency. | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7429 bool MarkFromRootsVerifyClosure::do_bit(size_t offset) { |
| 0 | 7430 // convert offset into a HeapWord* |
| 7431 HeapWord* addr = _verification_bm->startWord() + offset; | |
| 7432 assert(_verification_bm->endWord() && addr < _verification_bm->endWord(), | |
| 7433 "address out of range"); | |
| 7434 assert(_verification_bm->isMarked(addr), "tautology"); | |
| 7435 assert(_cms_bm->isMarked(addr), "tautology"); | |
| 7436 | |
| 7437 assert(_mark_stack->isEmpty(), | |
| 7438 "should drain stack to limit stack usage"); | |
| 7439 // convert addr to an oop preparatory to scanning | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7440 oop obj = oop(addr); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7441 assert(obj->is_oop(), "should be an oop"); |
| 0 | 7442 assert(_finger <= addr, "_finger runneth ahead"); |
| 7443 // advance the finger to right end of this object | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7444 _finger = addr + obj->size(); |
| 0 | 7445 assert(_finger > addr, "we just incremented it above"); |
| 7446 // Note: the finger doesn't advance while we drain | |
| 7447 // the stack below. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7448 bool res = _mark_stack->push(obj); |
| 0 | 7449 assert(res, "Empty non-zero size stack should have space for single push"); |
| 7450 while (!_mark_stack->isEmpty()) { | |
| 7451 oop new_oop = _mark_stack->pop(); | |
| 7452 assert(new_oop->is_oop(), "Oops! expected to pop an oop"); | |
| 7453 // now scan this oop's oops | |
| 7454 new_oop->oop_iterate(&_pam_verify_closure); | |
| 7455 } | |
| 7456 assert(_mark_stack->isEmpty(), "tautology, emphasizing post-condition"); | |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7457 return true; |
| 0 | 7458 } |
| 7459 | |
| 7460 PushAndMarkVerifyClosure::PushAndMarkVerifyClosure( | |
| 7461 CMSCollector* collector, MemRegion span, | |
| 7462 CMSBitMap* verification_bm, CMSBitMap* cms_bm, | |
| 7463 CMSMarkStack* mark_stack): | |
| 7464 OopClosure(collector->ref_processor()), | |
| 7465 _collector(collector), | |
| 7466 _span(span), | |
| 7467 _verification_bm(verification_bm), | |
| 7468 _cms_bm(cms_bm), | |
| 7469 _mark_stack(mark_stack) | |
| 7470 { } | |
| 7471 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7472 void PushAndMarkVerifyClosure::do_oop(oop* p) { PushAndMarkVerifyClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7473 void PushAndMarkVerifyClosure::do_oop(narrowOop* p) { PushAndMarkVerifyClosure::do_oop_work(p); } |
| 0 | 7474 |
| 7475 // Upon stack overflow, we discard (part of) the stack, | |
| 7476 // remembering the least address amongst those discarded | |
| 7477 // in CMSCollector's _restart_address. | |
| 7478 void PushAndMarkVerifyClosure::handle_stack_overflow(HeapWord* lost) { | |
| 7479 // Remember the least grey address discarded | |
| 7480 HeapWord* ra = (HeapWord*)_mark_stack->least_value(lost); | |
| 7481 _collector->lower_restart_addr(ra); | |
| 7482 _mark_stack->reset(); // discard stack contents | |
| 7483 _mark_stack->expand(); // expand the stack if possible | |
| 7484 } | |
| 7485 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7486 void PushAndMarkVerifyClosure::do_oop(oop obj) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7487 assert(obj->is_oop_or_null(), "expected an oop or NULL"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7488 HeapWord* addr = (HeapWord*)obj; |
| 0 | 7489 if (_span.contains(addr) && !_verification_bm->isMarked(addr)) { |
| 7490 // Oop lies in _span and isn't yet grey or black | |
| 7491 _verification_bm->mark(addr); // now grey | |
| 7492 if (!_cms_bm->isMarked(addr)) { | |
| 7493 oop(addr)->print(); | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7494 gclog_or_tty->print_cr(" (" INTPTR_FORMAT " should have been marked)", |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7495 addr); |
| 0 | 7496 fatal("... aborting"); |
| 7497 } | |
| 7498 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7499 if (!_mark_stack->push(obj)) { // stack overflow |
| 0 | 7500 if (PrintCMSStatistics != 0) { |
| 7501 gclog_or_tty->print_cr("CMS marking stack overflow (benign) at " | |
| 7502 SIZE_FORMAT, _mark_stack->capacity()); | |
| 7503 } | |
| 7504 assert(_mark_stack->isFull(), "Else push should have succeeded"); | |
| 7505 handle_stack_overflow(addr); | |
| 7506 } | |
| 7507 // anything including and to the right of _finger | |
| 7508 // will be scanned as we iterate over the remainder of the | |
| 7509 // bit map | |
| 7510 } | |
| 7511 } | |
| 7512 | |
| 7513 PushOrMarkClosure::PushOrMarkClosure(CMSCollector* collector, | |
| 7514 MemRegion span, | |
| 7515 CMSBitMap* bitMap, CMSMarkStack* markStack, | |
| 7516 CMSMarkStack* revisitStack, | |
| 7517 HeapWord* finger, MarkFromRootsClosure* parent) : | |
| 935 | 7518 KlassRememberingOopClosure(collector, collector->ref_processor(), revisitStack), |
| 0 | 7519 _span(span), |
| 7520 _bitMap(bitMap), | |
| 7521 _markStack(markStack), | |
| 7522 _finger(finger), | |
| 935 | 7523 _parent(parent) |
| 0 | 7524 { } |
| 7525 | |
| 7526 Par_PushOrMarkClosure::Par_PushOrMarkClosure(CMSCollector* collector, | |
| 7527 MemRegion span, | |
| 7528 CMSBitMap* bit_map, | |
| 7529 OopTaskQueue* work_queue, | |
| 7530 CMSMarkStack* overflow_stack, | |
| 7531 CMSMarkStack* revisit_stack, | |
| 7532 HeapWord* finger, | |
| 7533 HeapWord** global_finger_addr, | |
| 7534 Par_MarkFromRootsClosure* parent) : | |
| 935 | 7535 Par_KlassRememberingOopClosure(collector, |
| 7536 collector->ref_processor(), | |
| 7537 revisit_stack), | |
| 0 | 7538 _whole_span(collector->_span), |
| 7539 _span(span), | |
| 7540 _bit_map(bit_map), | |
| 7541 _work_queue(work_queue), | |
| 7542 _overflow_stack(overflow_stack), | |
| 7543 _finger(finger), | |
| 7544 _global_finger_addr(global_finger_addr), | |
| 935 | 7545 _parent(parent) |
| 0 | 7546 { } |
| 7547 | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
7548 // Assumes thread-safe access by callers, who are |
|
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
7549 // responsible for mutual exclusion. |
| 0 | 7550 void CMSCollector::lower_restart_addr(HeapWord* low) { |
| 7551 assert(_span.contains(low), "Out of bounds addr"); | |
| 7552 if (_restart_addr == NULL) { | |
| 7553 _restart_addr = low; | |
| 7554 } else { | |
| 7555 _restart_addr = MIN2(_restart_addr, low); | |
| 7556 } | |
| 7557 } | |
| 7558 | |
| 7559 // Upon stack overflow, we discard (part of) the stack, | |
| 7560 // remembering the least address amongst those discarded | |
| 7561 // in CMSCollector's _restart_address. | |
| 7562 void PushOrMarkClosure::handle_stack_overflow(HeapWord* lost) { | |
| 7563 // Remember the least grey address discarded | |
| 7564 HeapWord* ra = (HeapWord*)_markStack->least_value(lost); | |
| 7565 _collector->lower_restart_addr(ra); | |
| 7566 _markStack->reset(); // discard stack contents | |
| 7567 _markStack->expand(); // expand the stack if possible | |
| 7568 } | |
| 7569 | |
| 7570 // Upon stack overflow, we discard (part of) the stack, | |
| 7571 // remembering the least address amongst those discarded | |
| 7572 // in CMSCollector's _restart_address. | |
| 7573 void Par_PushOrMarkClosure::handle_stack_overflow(HeapWord* lost) { | |
| 7574 // We need to do this under a mutex to prevent other | |
|
340
ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
ysr
parents:
283
diff
changeset
|
7575 // workers from interfering with the work done below. |
| 0 | 7576 MutexLockerEx ml(_overflow_stack->par_lock(), |
| 7577 Mutex::_no_safepoint_check_flag); | |
| 7578 // Remember the least grey address discarded | |
| 7579 HeapWord* ra = (HeapWord*)_overflow_stack->least_value(lost); | |
| 7580 _collector->lower_restart_addr(ra); | |
| 7581 _overflow_stack->reset(); // discard stack contents | |
| 7582 _overflow_stack->expand(); // expand the stack if possible | |
| 7583 } | |
| 7584 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7585 void PushOrMarkClosure::do_oop(oop obj) { |
| 0 | 7586 // Ignore mark word because we are running concurrent with mutators. |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7587 assert(obj->is_oop_or_null(true), "expected an oop or NULL"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7588 HeapWord* addr = (HeapWord*)obj; |
| 0 | 7589 if (_span.contains(addr) && !_bitMap->isMarked(addr)) { |
| 7590 // Oop lies in _span and isn't yet grey or black | |
| 7591 _bitMap->mark(addr); // now grey | |
| 7592 if (addr < _finger) { | |
| 7593 // the bit map iteration has already either passed, or | |
| 7594 // sampled, this bit in the bit map; we'll need to | |
| 7595 // use the marking stack to scan this oop's oops. | |
| 7596 bool simulate_overflow = false; | |
| 7597 NOT_PRODUCT( | |
| 7598 if (CMSMarkStackOverflowALot && | |
| 7599 _collector->simulate_overflow()) { | |
| 7600 // simulate a stack overflow | |
| 7601 simulate_overflow = true; | |
| 7602 } | |
| 7603 ) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7604 if (simulate_overflow || !_markStack->push(obj)) { // stack overflow |
| 0 | 7605 if (PrintCMSStatistics != 0) { |
| 7606 gclog_or_tty->print_cr("CMS marking stack overflow (benign) at " | |
| 7607 SIZE_FORMAT, _markStack->capacity()); | |
| 7608 } | |
| 7609 assert(simulate_overflow || _markStack->isFull(), "Else push should have succeeded"); | |
| 7610 handle_stack_overflow(addr); | |
| 7611 } | |
| 7612 } | |
| 7613 // anything including and to the right of _finger | |
| 7614 // will be scanned as we iterate over the remainder of the | |
| 7615 // bit map | |
| 7616 do_yield_check(); | |
| 7617 } | |
| 7618 } | |
| 7619 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7620 void PushOrMarkClosure::do_oop(oop* p) { PushOrMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7621 void PushOrMarkClosure::do_oop(narrowOop* p) { PushOrMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7622 |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7623 void Par_PushOrMarkClosure::do_oop(oop obj) { |
| 0 | 7624 // Ignore mark word because we are running concurrent with mutators. |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7625 assert(obj->is_oop_or_null(true), "expected an oop or NULL"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7626 HeapWord* addr = (HeapWord*)obj; |
| 0 | 7627 if (_whole_span.contains(addr) && !_bit_map->isMarked(addr)) { |
| 7628 // Oop lies in _span and isn't yet grey or black | |
| 7629 // We read the global_finger (volatile read) strictly after marking oop | |
| 7630 bool res = _bit_map->par_mark(addr); // now grey | |
| 7631 volatile HeapWord** gfa = (volatile HeapWord**)_global_finger_addr; | |
| 7632 // Should we push this marked oop on our stack? | |
| 7633 // -- if someone else marked it, nothing to do | |
| 7634 // -- if target oop is above global finger nothing to do | |
| 7635 // -- if target oop is in chunk and above local finger | |
| 7636 // then nothing to do | |
| 7637 // -- else push on work queue | |
| 7638 if ( !res // someone else marked it, they will deal with it | |
| 7639 || (addr >= *gfa) // will be scanned in a later task | |
| 7640 || (_span.contains(addr) && addr >= _finger)) { // later in this chunk | |
| 7641 return; | |
| 7642 } | |
| 7643 // the bit map iteration has already either passed, or | |
| 7644 // sampled, this bit in the bit map; we'll need to | |
| 7645 // use the marking stack to scan this oop's oops. | |
| 7646 bool simulate_overflow = false; | |
| 7647 NOT_PRODUCT( | |
| 7648 if (CMSMarkStackOverflowALot && | |
| 7649 _collector->simulate_overflow()) { | |
| 7650 // simulate a stack overflow | |
| 7651 simulate_overflow = true; | |
| 7652 } | |
| 7653 ) | |
| 7654 if (simulate_overflow || | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7655 !(_work_queue->push(obj) || _overflow_stack->par_push(obj))) { |
| 0 | 7656 // stack overflow |
| 7657 if (PrintCMSStatistics != 0) { | |
| 7658 gclog_or_tty->print_cr("CMS marking stack overflow (benign) at " | |
| 7659 SIZE_FORMAT, _overflow_stack->capacity()); | |
| 7660 } | |
| 7661 // We cannot assert that the overflow stack is full because | |
| 7662 // it may have been emptied since. | |
| 7663 assert(simulate_overflow || | |
| 7664 _work_queue->size() == _work_queue->max_elems(), | |
| 7665 "Else push should have succeeded"); | |
| 7666 handle_stack_overflow(addr); | |
| 7667 } | |
| 7668 do_yield_check(); | |
| 7669 } | |
| 7670 } | |
| 7671 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7672 void Par_PushOrMarkClosure::do_oop(oop* p) { Par_PushOrMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7673 void Par_PushOrMarkClosure::do_oop(narrowOop* p) { Par_PushOrMarkClosure::do_oop_work(p); } |
| 0 | 7674 |
| 935 | 7675 KlassRememberingOopClosure::KlassRememberingOopClosure(CMSCollector* collector, |
| 7676 ReferenceProcessor* rp, | |
| 7677 CMSMarkStack* revisit_stack) : | |
| 7678 OopClosure(rp), | |
| 7679 _collector(collector), | |
| 7680 _revisit_stack(revisit_stack), | |
| 7681 _should_remember_klasses(collector->should_unload_classes()) {} | |
| 7682 | |
| 0 | 7683 PushAndMarkClosure::PushAndMarkClosure(CMSCollector* collector, |
| 7684 MemRegion span, | |
| 7685 ReferenceProcessor* rp, | |
| 7686 CMSBitMap* bit_map, | |
| 7687 CMSBitMap* mod_union_table, | |
| 7688 CMSMarkStack* mark_stack, | |
| 7689 CMSMarkStack* revisit_stack, | |
| 7690 bool concurrent_precleaning): | |
| 935 | 7691 KlassRememberingOopClosure(collector, rp, revisit_stack), |
| 0 | 7692 _span(span), |
| 7693 _bit_map(bit_map), | |
| 7694 _mod_union_table(mod_union_table), | |
| 7695 _mark_stack(mark_stack), | |
| 935 | 7696 _concurrent_precleaning(concurrent_precleaning) |
| 0 | 7697 { |
| 7698 assert(_ref_processor != NULL, "_ref_processor shouldn't be NULL"); | |
| 7699 } | |
| 7700 | |
| 7701 // Grey object rescan during pre-cleaning and second checkpoint phases -- | |
| 7702 // the non-parallel version (the parallel version appears further below.) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7703 void PushAndMarkClosure::do_oop(oop obj) { |
|
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7704 // Ignore mark word verification. If during concurrent precleaning, |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7705 // the object monitor may be locked. If during the checkpoint |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7706 // phases, the object may already have been reached by a different |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7707 // path and may be at the end of the global overflow list (so |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7708 // the mark word may be NULL). |
|
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
143
diff
changeset
|
7709 assert(obj->is_oop_or_null(true /* ignore mark word */), |
| 0 | 7710 "expected an oop or NULL"); |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7711 HeapWord* addr = (HeapWord*)obj; |
| 0 | 7712 // Check if oop points into the CMS generation |
| 7713 // and is not marked | |
| 7714 if (_span.contains(addr) && !_bit_map->isMarked(addr)) { | |
| 7715 // a white object ... | |
| 7716 _bit_map->mark(addr); // ... now grey | |
| 7717 // push on the marking stack (grey set) | |
| 7718 bool simulate_overflow = false; | |
| 7719 NOT_PRODUCT( | |
| 7720 if (CMSMarkStackOverflowALot && | |
| 7721 _collector->simulate_overflow()) { | |
| 7722 // simulate a stack overflow | |
| 7723 simulate_overflow = true; | |
| 7724 } | |
| 7725 ) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7726 if (simulate_overflow || !_mark_stack->push(obj)) { |
| 0 | 7727 if (_concurrent_precleaning) { |
|
283
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7728 // During precleaning we can just dirty the appropriate card(s) |
| 0 | 7729 // in the mod union table, thus ensuring that the object remains |
|
283
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7730 // in the grey set and continue. In the case of object arrays |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7731 // we need to dirty all of the cards that the object spans, |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7732 // since the rescan of object arrays will be limited to the |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7733 // dirty cards. |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7734 // Note that no one can be intefering with us in this action |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7735 // of dirtying the mod union table, so no locking or atomics |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7736 // are required. |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7737 if (obj->is_objArray()) { |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7738 size_t sz = obj->size(); |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7739 HeapWord* end_card_addr = (HeapWord*)round_to( |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7740 (intptr_t)(addr+sz), CardTableModRefBS::card_size); |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7741 MemRegion redirty_range = MemRegion(addr, end_card_addr); |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7742 assert(!redirty_range.is_empty(), "Arithmetical tautology"); |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7743 _mod_union_table->mark_range(redirty_range); |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7744 } else { |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7745 _mod_union_table->mark(addr); |
|
9199f248b0ee
6722112: CMS: Incorrect encoding of overflown object arrays during concurrent precleaning
ysr
parents:
271
diff
changeset
|
7746 } |
| 0 | 7747 _collector->_ser_pmc_preclean_ovflw++; |
| 7748 } else { | |
| 7749 // During the remark phase, we need to remember this oop | |
| 7750 // in the overflow list. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7751 _collector->push_on_overflow_list(obj); |
| 0 | 7752 _collector->_ser_pmc_remark_ovflw++; |
| 7753 } | |
| 7754 } | |
| 7755 } | |
| 7756 } | |
| 7757 | |
| 7758 Par_PushAndMarkClosure::Par_PushAndMarkClosure(CMSCollector* collector, | |
| 7759 MemRegion span, | |
| 7760 ReferenceProcessor* rp, | |
| 7761 CMSBitMap* bit_map, | |
| 7762 OopTaskQueue* work_queue, | |
| 7763 CMSMarkStack* revisit_stack): | |
| 935 | 7764 Par_KlassRememberingOopClosure(collector, rp, revisit_stack), |
| 0 | 7765 _span(span), |
| 7766 _bit_map(bit_map), | |
| 935 | 7767 _work_queue(work_queue) |
| 0 | 7768 { |
| 7769 assert(_ref_processor != NULL, "_ref_processor shouldn't be NULL"); | |
| 7770 } | |
| 7771 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7772 void PushAndMarkClosure::do_oop(oop* p) { PushAndMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7773 void PushAndMarkClosure::do_oop(narrowOop* p) { PushAndMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7774 |
| 0 | 7775 // Grey object rescan during second checkpoint phase -- |
| 7776 // the parallel version. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7777 void Par_PushAndMarkClosure::do_oop(oop obj) { |
| 0 | 7778 // In the assert below, we ignore the mark word because |
| 7779 // this oop may point to an already visited object that is | |
| 7780 // on the overflow stack (in which case the mark word has | |
| 7781 // been hijacked for chaining into the overflow stack -- | |
| 7782 // if this is the last object in the overflow stack then | |
| 7783 // its mark word will be NULL). Because this object may | |
| 7784 // have been subsequently popped off the global overflow | |
| 7785 // stack, and the mark word possibly restored to the prototypical | |
| 7786 // value, by the time we get to examined this failing assert in | |
| 7787 // the debugger, is_oop_or_null(false) may subsequently start | |
| 7788 // to hold. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7789 assert(obj->is_oop_or_null(true), |
| 0 | 7790 "expected an oop or NULL"); |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7791 HeapWord* addr = (HeapWord*)obj; |
| 0 | 7792 // Check if oop points into the CMS generation |
| 7793 // and is not marked | |
| 7794 if (_span.contains(addr) && !_bit_map->isMarked(addr)) { | |
| 7795 // a white object ... | |
| 7796 // If we manage to "claim" the object, by being the | |
| 7797 // first thread to mark it, then we push it on our | |
| 7798 // marking stack | |
| 7799 if (_bit_map->par_mark(addr)) { // ... now grey | |
| 7800 // push on work queue (grey set) | |
| 7801 bool simulate_overflow = false; | |
| 7802 NOT_PRODUCT( | |
| 7803 if (CMSMarkStackOverflowALot && | |
| 7804 _collector->par_simulate_overflow()) { | |
| 7805 // simulate a stack overflow | |
| 7806 simulate_overflow = true; | |
| 7807 } | |
| 7808 ) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7809 if (simulate_overflow || !_work_queue->push(obj)) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7810 _collector->par_push_on_overflow_list(obj); |
| 0 | 7811 _collector->_par_pmc_remark_ovflw++; // imprecise OK: no need to CAS |
| 7812 } | |
| 7813 } // Else, some other thread got there first | |
| 7814 } | |
| 7815 } | |
| 7816 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7817 void Par_PushAndMarkClosure::do_oop(oop* p) { Par_PushAndMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7818 void Par_PushAndMarkClosure::do_oop(narrowOop* p) { Par_PushAndMarkClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
7819 |
| 941 | 7820 void PushAndMarkClosure::remember_mdo(DataLayout* v) { |
| 7821 // TBD | |
| 7822 } | |
| 7823 | |
| 7824 void Par_PushAndMarkClosure::remember_mdo(DataLayout* v) { | |
| 7825 // TBD | |
| 7826 } | |
| 7827 | |
| 0 | 7828 void CMSPrecleanRefsYieldClosure::do_yield_work() { |
| 935 | 7829 DEBUG_ONLY(RememberKlassesChecker mux(false);) |
| 0 | 7830 Mutex* bml = _collector->bitMapLock(); |
| 7831 assert_lock_strong(bml); | |
| 7832 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 7833 "CMS thread should hold CMS token"); | |
| 7834 | |
| 7835 bml->unlock(); | |
| 7836 ConcurrentMarkSweepThread::desynchronize(true); | |
| 7837 | |
| 7838 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 7839 | |
| 7840 _collector->stopTimer(); | |
| 7841 GCPauseTimer p(_collector->size_policy()->concurrent_timer_ptr()); | |
| 7842 if (PrintCMSStatistics != 0) { | |
| 7843 _collector->incrementYields(); | |
| 7844 } | |
| 7845 _collector->icms_wait(); | |
| 7846 | |
| 7847 // See the comment in coordinator_yield() | |
| 7848 for (unsigned i = 0; i < CMSYieldSleepCount && | |
| 7849 ConcurrentMarkSweepThread::should_yield() && | |
| 7850 !CMSCollector::foregroundGCIsActive(); ++i) { | |
| 7851 os::sleep(Thread::current(), 1, false); | |
| 7852 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 7853 } | |
| 7854 | |
| 7855 ConcurrentMarkSweepThread::synchronize(true); | |
| 7856 bml->lock(); | |
| 7857 | |
| 7858 _collector->startTimer(); | |
| 7859 } | |
| 7860 | |
| 7861 bool CMSPrecleanRefsYieldClosure::should_return() { | |
| 7862 if (ConcurrentMarkSweepThread::should_yield()) { | |
| 7863 do_yield_work(); | |
| 7864 } | |
| 7865 return _collector->foregroundGCIsActive(); | |
| 7866 } | |
| 7867 | |
| 7868 void MarkFromDirtyCardsClosure::do_MemRegion(MemRegion mr) { | |
| 7869 assert(((size_t)mr.start())%CardTableModRefBS::card_size_in_words == 0, | |
| 7870 "mr should be aligned to start at a card boundary"); | |
| 7871 // We'd like to assert: | |
| 7872 // assert(mr.word_size()%CardTableModRefBS::card_size_in_words == 0, | |
| 7873 // "mr should be a range of cards"); | |
| 7874 // However, that would be too strong in one case -- the last | |
| 7875 // partition ends at _unallocated_block which, in general, can be | |
| 7876 // an arbitrary boundary, not necessarily card aligned. | |
| 7877 if (PrintCMSStatistics != 0) { | |
| 7878 _num_dirty_cards += | |
| 7879 mr.word_size()/CardTableModRefBS::card_size_in_words; | |
| 7880 } | |
| 7881 _space->object_iterate_mem(mr, &_scan_cl); | |
| 7882 } | |
| 7883 | |
| 7884 SweepClosure::SweepClosure(CMSCollector* collector, | |
| 7885 ConcurrentMarkSweepGeneration* g, | |
| 7886 CMSBitMap* bitMap, bool should_yield) : | |
| 7887 _collector(collector), | |
| 7888 _g(g), | |
| 7889 _sp(g->cmsSpace()), | |
| 7890 _limit(_sp->sweep_limit()), | |
| 7891 _freelistLock(_sp->freelistLock()), | |
| 7892 _bitMap(bitMap), | |
| 7893 _yield(should_yield), | |
| 7894 _inFreeRange(false), // No free range at beginning of sweep | |
| 7895 _freeRangeInFreeLists(false), // No free range at beginning of sweep | |
| 7896 _lastFreeRangeCoalesced(false), | |
| 7897 _freeFinger(g->used_region().start()) | |
| 7898 { | |
| 7899 NOT_PRODUCT( | |
| 7900 _numObjectsFreed = 0; | |
| 7901 _numWordsFreed = 0; | |
| 7902 _numObjectsLive = 0; | |
| 7903 _numWordsLive = 0; | |
| 7904 _numObjectsAlreadyFree = 0; | |
| 7905 _numWordsAlreadyFree = 0; | |
| 7906 _last_fc = NULL; | |
| 7907 | |
| 7908 _sp->initializeIndexedFreeListArrayReturnedBytes(); | |
| 7909 _sp->dictionary()->initializeDictReturnedBytes(); | |
| 7910 ) | |
| 7911 assert(_limit >= _sp->bottom() && _limit <= _sp->end(), | |
| 7912 "sweep _limit out of bounds"); | |
| 7913 if (CMSTraceSweeper) { | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7914 gclog_or_tty->print_cr("\n====================\nStarting new sweep with limit " PTR_FORMAT, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7915 _limit); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7916 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7917 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7918 |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7919 void SweepClosure::print_on(outputStream* st) const { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7920 tty->print_cr("_sp = [" PTR_FORMAT "," PTR_FORMAT ")", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7921 _sp->bottom(), _sp->end()); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7922 tty->print_cr("_limit = " PTR_FORMAT, _limit); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7923 tty->print_cr("_freeFinger = " PTR_FORMAT, _freeFinger); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7924 NOT_PRODUCT(tty->print_cr("_last_fc = " PTR_FORMAT, _last_fc);) |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7925 tty->print_cr("_inFreeRange = %d, _freeRangeInFreeLists = %d, _lastFreeRangeCoalesced = %d", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7926 _inFreeRange, _freeRangeInFreeLists, _lastFreeRangeCoalesced); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7927 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7928 |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7929 #ifndef PRODUCT |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7930 // Assertion checking only: no useful work in product mode -- |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7931 // however, if any of the flags below become product flags, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7932 // you may need to review this code to see if it needs to be |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7933 // enabled in product mode. |
| 0 | 7934 SweepClosure::~SweepClosure() { |
| 7935 assert_lock_strong(_freelistLock); | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
7936 assert(_limit >= _sp->bottom() && _limit <= _sp->end(), |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
7937 "sweep _limit out of bounds"); |
| 0 | 7938 if (inFreeRange()) { |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7939 warning("inFreeRange() should have been reset; dumping state of SweepClosure"); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7940 print(); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7941 ShouldNotReachHere(); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7942 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7943 if (Verbose && PrintGC) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7944 gclog_or_tty->print("Collected "SIZE_FORMAT" objects, " SIZE_FORMAT " bytes", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7945 _numObjectsFreed, _numWordsFreed*sizeof(HeapWord)); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7946 gclog_or_tty->print_cr("\nLive "SIZE_FORMAT" objects, " |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7947 SIZE_FORMAT" bytes " |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7948 "Already free "SIZE_FORMAT" objects, "SIZE_FORMAT" bytes", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7949 _numObjectsLive, _numWordsLive*sizeof(HeapWord), |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7950 _numObjectsAlreadyFree, _numWordsAlreadyFree*sizeof(HeapWord)); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7951 size_t totalBytes = (_numWordsFreed + _numWordsLive + _numWordsAlreadyFree) |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7952 * sizeof(HeapWord); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7953 gclog_or_tty->print_cr("Total sweep: "SIZE_FORMAT" bytes", totalBytes); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7954 |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7955 if (PrintCMSStatistics && CMSVerifyReturnedBytes) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7956 size_t indexListReturnedBytes = _sp->sumIndexedFreeListArrayReturnedBytes(); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7957 size_t dictReturnedBytes = _sp->dictionary()->sumDictReturnedBytes(); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7958 size_t returnedBytes = indexListReturnedBytes + dictReturnedBytes; |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7959 gclog_or_tty->print("Returned "SIZE_FORMAT" bytes", returnedBytes); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7960 gclog_or_tty->print(" Indexed List Returned "SIZE_FORMAT" bytes", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7961 indexListReturnedBytes); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7962 gclog_or_tty->print_cr(" Dictionary Returned "SIZE_FORMAT" bytes", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7963 dictReturnedBytes); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7964 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7965 } |
| 0 | 7966 if (CMSTraceSweeper) { |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7967 gclog_or_tty->print_cr("end of sweep with _limit = " PTR_FORMAT "\n================", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7968 _limit); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7969 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7970 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
7971 #endif // PRODUCT |
| 0 | 7972 |
| 7973 void SweepClosure::initialize_free_range(HeapWord* freeFinger, | |
| 7974 bool freeRangeInFreeLists) { | |
| 7975 if (CMSTraceSweeper) { | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
7976 gclog_or_tty->print("---- Start free range at 0x%x with free block (%d)\n", |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
7977 freeFinger, freeRangeInFreeLists); |
| 0 | 7978 } |
| 7979 assert(!inFreeRange(), "Trampling existing free range"); | |
| 7980 set_inFreeRange(true); | |
| 7981 set_lastFreeRangeCoalesced(false); | |
| 7982 | |
| 7983 set_freeFinger(freeFinger); | |
| 7984 set_freeRangeInFreeLists(freeRangeInFreeLists); | |
| 7985 if (CMSTestInFreeList) { | |
| 7986 if (freeRangeInFreeLists) { | |
| 7987 FreeChunk* fc = (FreeChunk*) freeFinger; | |
| 7988 assert(fc->isFree(), "A chunk on the free list should be free."); | |
| 7989 assert(fc->size() > 0, "Free range should have a size"); | |
| 7990 assert(_sp->verifyChunkInFreeLists(fc), "Chunk is not in free lists"); | |
| 7991 } | |
| 7992 } | |
| 7993 } | |
| 7994 | |
| 7995 // Note that the sweeper runs concurrently with mutators. Thus, | |
| 7996 // it is possible for direct allocation in this generation to happen | |
| 7997 // in the middle of the sweep. Note that the sweeper also coalesces | |
| 7998 // contiguous free blocks. Thus, unless the sweeper and the allocator | |
| 7999 // synchronize appropriately freshly allocated blocks may get swept up. | |
| 8000 // This is accomplished by the sweeper locking the free lists while | |
| 8001 // it is sweeping. Thus blocks that are determined to be free are | |
| 8002 // indeed free. There is however one additional complication: | |
| 8003 // blocks that have been allocated since the final checkpoint and | |
| 8004 // mark, will not have been marked and so would be treated as | |
| 8005 // unreachable and swept up. To prevent this, the allocator marks | |
| 8006 // the bit map when allocating during the sweep phase. This leads, | |
| 8007 // however, to a further complication -- objects may have been allocated | |
| 8008 // but not yet initialized -- in the sense that the header isn't yet | |
| 8009 // installed. The sweeper can not then determine the size of the block | |
| 8010 // in order to skip over it. To deal with this case, we use a technique | |
| 8011 // (due to Printezis) to encode such uninitialized block sizes in the | |
| 8012 // bit map. Since the bit map uses a bit per every HeapWord, but the | |
| 8013 // CMS generation has a minimum object size of 3 HeapWords, it follows | |
| 8014 // that "normal marks" won't be adjacent in the bit map (there will | |
| 8015 // always be at least two 0 bits between successive 1 bits). We make use | |
| 8016 // of these "unused" bits to represent uninitialized blocks -- the bit | |
| 8017 // corresponding to the start of the uninitialized object and the next | |
| 8018 // bit are both set. Finally, a 1 bit marks the end of the object that | |
| 8019 // started with the two consecutive 1 bits to indicate its potentially | |
| 8020 // uninitialized state. | |
| 8021 | |
| 8022 size_t SweepClosure::do_blk_careful(HeapWord* addr) { | |
| 8023 FreeChunk* fc = (FreeChunk*)addr; | |
| 8024 size_t res; | |
| 8025 | |
|
1720
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8026 // Check if we are done sweeping. Below we check "addr >= _limit" rather |
|
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8027 // than "addr == _limit" because although _limit was a block boundary when |
|
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8028 // we started the sweep, it may no longer be one because heap expansion |
|
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8029 // may have caused us to coalesce the block ending at the address _limit |
|
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8030 // with a newly expanded chunk (this happens when _limit was set to the |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8031 // previous _end of the space), so we may have stepped past _limit: |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8032 // see the following Zeno-like trail of CRs 6977970, 7008136, 7042740. |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8033 if (addr >= _limit) { // we have swept up to or past the limit: finish up |
| 0 | 8034 assert(_limit >= _sp->bottom() && _limit <= _sp->end(), |
| 8035 "sweep _limit out of bounds"); | |
|
1720
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8036 assert(addr < _sp->end(), "addr out of bounds"); |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8037 // Flush any free range we might be holding as a single |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8038 // coalesced chunk to the appropriate free list. |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8039 if (inFreeRange()) { |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8040 assert(freeFinger() >= _sp->bottom() && freeFinger() < _limit, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8041 err_msg("freeFinger() " PTR_FORMAT" is out-of-bounds", freeFinger())); |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8042 flush_cur_free_chunk(freeFinger(), |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8043 pointer_delta(addr, freeFinger())); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8044 if (CMSTraceSweeper) { |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8045 gclog_or_tty->print("Sweep: last chunk: "); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8046 gclog_or_tty->print("put_free_blk 0x%x ("SIZE_FORMAT") " |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8047 "[coalesced:"SIZE_FORMAT"]\n", |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8048 freeFinger(), pointer_delta(addr, freeFinger()), |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8049 lastFreeRangeCoalesced()); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8050 } |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8051 } |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8052 |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8053 // help the iterator loop finish |
|
1720
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8054 return pointer_delta(_sp->end(), addr); |
|
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8055 } |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8056 |
|
1720
5ed703250bff
6977970: CMS: concurrentMarkSweepGeneration.cpp:7947 assert(addr <= _limit) failed: sweep invariant
ysr
parents:
1716
diff
changeset
|
8057 assert(addr < _limit, "sweep invariant"); |
| 0 | 8058 // check if we should yield |
| 8059 do_yield_check(addr); | |
| 8060 if (fc->isFree()) { | |
| 8061 // Chunk that is already free | |
| 8062 res = fc->size(); | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8063 do_already_free_chunk(fc); |
| 0 | 8064 debug_only(_sp->verifyFreeLists()); |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8065 // If we flush the chunk at hand in lookahead_and_flush() |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8066 // and it's coalesced with a preceding chunk, then the |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8067 // process of "mangling" the payload of the coalesced block |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8068 // will cause erasure of the size information from the |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8069 // (erstwhile) header of all the coalesced blocks but the |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8070 // first, so the first disjunct in the assert will not hold |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8071 // in that specific case (in which case the second disjunct |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8072 // will hold). |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8073 assert(res == fc->size() || ((HeapWord*)fc) + res >= _limit, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8074 "Otherwise the size info doesn't change at this step"); |
| 0 | 8075 NOT_PRODUCT( |
| 8076 _numObjectsAlreadyFree++; | |
| 8077 _numWordsAlreadyFree += res; | |
| 8078 ) | |
| 8079 NOT_PRODUCT(_last_fc = fc;) | |
| 8080 } else if (!_bitMap->isMarked(addr)) { | |
| 8081 // Chunk is fresh garbage | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8082 res = do_garbage_chunk(fc); |
| 0 | 8083 debug_only(_sp->verifyFreeLists()); |
| 8084 NOT_PRODUCT( | |
| 8085 _numObjectsFreed++; | |
| 8086 _numWordsFreed += res; | |
| 8087 ) | |
| 8088 } else { | |
| 8089 // Chunk that is alive. | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8090 res = do_live_chunk(fc); |
| 0 | 8091 debug_only(_sp->verifyFreeLists()); |
| 8092 NOT_PRODUCT( | |
| 8093 _numObjectsLive++; | |
| 8094 _numWordsLive += res; | |
| 8095 ) | |
| 8096 } | |
| 8097 return res; | |
| 8098 } | |
| 8099 | |
| 8100 // For the smart allocation, record following | |
| 8101 // split deaths - a free chunk is removed from its free list because | |
| 8102 // it is being split into two or more chunks. | |
| 8103 // split birth - a free chunk is being added to its free list because | |
| 8104 // a larger free chunk has been split and resulted in this free chunk. | |
| 8105 // coal death - a free chunk is being removed from its free list because | |
| 8106 // it is being coalesced into a large free chunk. | |
| 8107 // coal birth - a free chunk is being added to its free list because | |
| 8108 // it was created when two or more free chunks where coalesced into | |
| 8109 // this free chunk. | |
| 8110 // | |
| 8111 // These statistics are used to determine the desired number of free | |
| 8112 // chunks of a given size. The desired number is chosen to be relative | |
| 8113 // to the end of a CMS sweep. The desired number at the end of a sweep | |
| 8114 // is the | |
| 8115 // count-at-end-of-previous-sweep (an amount that was enough) | |
| 8116 // - count-at-beginning-of-current-sweep (the excess) | |
| 8117 // + split-births (gains in this size during interval) | |
| 8118 // - split-deaths (demands on this size during interval) | |
| 8119 // where the interval is from the end of one sweep to the end of the | |
| 8120 // next. | |
| 8121 // | |
| 8122 // When sweeping the sweeper maintains an accumulated chunk which is | |
| 8123 // the chunk that is made up of chunks that have been coalesced. That | |
| 8124 // will be termed the left-hand chunk. A new chunk of garbage that | |
| 8125 // is being considered for coalescing will be referred to as the | |
| 8126 // right-hand chunk. | |
| 8127 // | |
| 8128 // When making a decision on whether to coalesce a right-hand chunk with | |
| 8129 // the current left-hand chunk, the current count vs. the desired count | |
| 8130 // of the left-hand chunk is considered. Also if the right-hand chunk | |
| 8131 // is near the large chunk at the end of the heap (see | |
| 8132 // ConcurrentMarkSweepGeneration::isNearLargestChunk()), then the | |
| 8133 // left-hand chunk is coalesced. | |
| 8134 // | |
| 8135 // When making a decision about whether to split a chunk, the desired count | |
| 8136 // vs. the current count of the candidate to be split is also considered. | |
| 8137 // If the candidate is underpopulated (currently fewer chunks than desired) | |
| 8138 // a chunk of an overpopulated (currently more chunks than desired) size may | |
| 8139 // be chosen. The "hint" associated with a free list, if non-null, points | |
| 8140 // to a free list which may be overpopulated. | |
| 8141 // | |
| 8142 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8143 void SweepClosure::do_already_free_chunk(FreeChunk* fc) { |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8144 const size_t size = fc->size(); |
| 0 | 8145 // Chunks that cannot be coalesced are not in the |
| 8146 // free lists. | |
| 8147 if (CMSTestInFreeList && !fc->cantCoalesce()) { | |
| 8148 assert(_sp->verifyChunkInFreeLists(fc), | |
| 8149 "free chunk should be in free lists"); | |
| 8150 } | |
| 8151 // a chunk that is already free, should not have been | |
| 8152 // marked in the bit map | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8153 HeapWord* const addr = (HeapWord*) fc; |
| 0 | 8154 assert(!_bitMap->isMarked(addr), "free chunk should be unmarked"); |
| 8155 // Verify that the bit map has no bits marked between | |
| 8156 // addr and purported end of this block. | |
| 8157 _bitMap->verifyNoOneBitsInRange(addr + 1, addr + size); | |
| 8158 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8159 // Some chunks cannot be coalesced under any circumstances. |
| 0 | 8160 // See the definition of cantCoalesce(). |
| 8161 if (!fc->cantCoalesce()) { | |
| 8162 // This chunk can potentially be coalesced. | |
| 8163 if (_sp->adaptive_freelists()) { | |
| 8164 // All the work is done in | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8165 do_post_free_or_garbage_chunk(fc, size); |
| 0 | 8166 } else { // Not adaptive free lists |
| 8167 // this is a free chunk that can potentially be coalesced by the sweeper; | |
| 8168 if (!inFreeRange()) { | |
| 8169 // if the next chunk is a free block that can't be coalesced | |
| 8170 // it doesn't make sense to remove this chunk from the free lists | |
| 8171 FreeChunk* nextChunk = (FreeChunk*)(addr + size); | |
|
2136
c91cc404ca46
7011940: iCMS: SIGSEGV in SweepClosure::do_already_free_chunk(FreeChunk*)+0x360
ysr
parents:
2132
diff
changeset
|
8172 assert((HeapWord*)nextChunk <= _sp->end(), "Chunk size out of bounds?"); |
|
c91cc404ca46
7011940: iCMS: SIGSEGV in SweepClosure::do_already_free_chunk(FreeChunk*)+0x360
ysr
parents:
2132
diff
changeset
|
8173 if ((HeapWord*)nextChunk < _sp->end() && // There is another free chunk to the right ... |
|
c91cc404ca46
7011940: iCMS: SIGSEGV in SweepClosure::do_already_free_chunk(FreeChunk*)+0x360
ysr
parents:
2132
diff
changeset
|
8174 nextChunk->isFree() && // ... which is free... |
|
c91cc404ca46
7011940: iCMS: SIGSEGV in SweepClosure::do_already_free_chunk(FreeChunk*)+0x360
ysr
parents:
2132
diff
changeset
|
8175 nextChunk->cantCoalesce()) { // ... but can't be coalesced |
| 0 | 8176 // nothing to do |
| 8177 } else { | |
| 8178 // Potentially the start of a new free range: | |
| 8179 // Don't eagerly remove it from the free lists. | |
| 8180 // No need to remove it if it will just be put | |
| 8181 // back again. (Also from a pragmatic point of view | |
| 8182 // if it is a free block in a region that is beyond | |
| 8183 // any allocated blocks, an assertion will fail) | |
| 8184 // Remember the start of a free run. | |
| 8185 initialize_free_range(addr, true); | |
| 8186 // end - can coalesce with next chunk | |
| 8187 } | |
| 8188 } else { | |
| 8189 // the midst of a free range, we are coalescing | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8190 print_free_block_coalesced(fc); |
| 0 | 8191 if (CMSTraceSweeper) { |
| 8192 gclog_or_tty->print(" -- pick up free block 0x%x (%d)\n", fc, size); | |
| 8193 } | |
| 8194 // remove it from the free lists | |
| 8195 _sp->removeFreeChunkFromFreeLists(fc); | |
| 8196 set_lastFreeRangeCoalesced(true); | |
| 8197 // If the chunk is being coalesced and the current free range is | |
| 8198 // in the free lists, remove the current free range so that it | |
| 8199 // will be returned to the free lists in its entirety - all | |
| 8200 // the coalesced pieces included. | |
| 8201 if (freeRangeInFreeLists()) { | |
| 8202 FreeChunk* ffc = (FreeChunk*) freeFinger(); | |
| 8203 assert(ffc->size() == pointer_delta(addr, freeFinger()), | |
| 8204 "Size of free range is inconsistent with chunk size."); | |
| 8205 if (CMSTestInFreeList) { | |
| 8206 assert(_sp->verifyChunkInFreeLists(ffc), | |
| 8207 "free range is not in free lists"); | |
| 8208 } | |
| 8209 _sp->removeFreeChunkFromFreeLists(ffc); | |
| 8210 set_freeRangeInFreeLists(false); | |
| 8211 } | |
| 8212 } | |
| 8213 } | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8214 // Note that if the chunk is not coalescable (the else arm |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8215 // below), we unconditionally flush, without needing to do |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8216 // a "lookahead," as we do below. |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8217 if (inFreeRange()) lookahead_and_flush(fc, size); |
| 0 | 8218 } else { |
| 8219 // Code path common to both original and adaptive free lists. | |
| 8220 | |
| 8221 // cant coalesce with previous block; this should be treated | |
| 8222 // as the end of a free run if any | |
| 8223 if (inFreeRange()) { | |
| 8224 // we kicked some butt; time to pick up the garbage | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8225 assert(freeFinger() < addr, "freeFinger points too high"); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8226 flush_cur_free_chunk(freeFinger(), pointer_delta(addr, freeFinger())); |
| 0 | 8227 } |
| 8228 // else, nothing to do, just continue | |
| 8229 } | |
| 8230 } | |
| 8231 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8232 size_t SweepClosure::do_garbage_chunk(FreeChunk* fc) { |
| 0 | 8233 // This is a chunk of garbage. It is not in any free list. |
| 8234 // Add it to a free list or let it possibly be coalesced into | |
| 8235 // a larger chunk. | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8236 HeapWord* const addr = (HeapWord*) fc; |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8237 const size_t size = CompactibleFreeListSpace::adjustObjectSize(oop(addr)->size()); |
| 0 | 8238 |
| 8239 if (_sp->adaptive_freelists()) { | |
| 8240 // Verify that the bit map has no bits marked between | |
| 8241 // addr and purported end of just dead object. | |
| 8242 _bitMap->verifyNoOneBitsInRange(addr + 1, addr + size); | |
| 8243 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8244 do_post_free_or_garbage_chunk(fc, size); |
| 0 | 8245 } else { |
| 8246 if (!inFreeRange()) { | |
| 8247 // start of a new free range | |
| 8248 assert(size > 0, "A free range should have a size"); | |
| 8249 initialize_free_range(addr, false); | |
| 8250 } else { | |
| 8251 // this will be swept up when we hit the end of the | |
| 8252 // free range | |
| 8253 if (CMSTraceSweeper) { | |
| 8254 gclog_or_tty->print(" -- pick up garbage 0x%x (%d) \n", fc, size); | |
| 8255 } | |
| 8256 // If the chunk is being coalesced and the current free range is | |
| 8257 // in the free lists, remove the current free range so that it | |
| 8258 // will be returned to the free lists in its entirety - all | |
| 8259 // the coalesced pieces included. | |
| 8260 if (freeRangeInFreeLists()) { | |
| 8261 FreeChunk* ffc = (FreeChunk*)freeFinger(); | |
| 8262 assert(ffc->size() == pointer_delta(addr, freeFinger()), | |
| 8263 "Size of free range is inconsistent with chunk size."); | |
| 8264 if (CMSTestInFreeList) { | |
| 8265 assert(_sp->verifyChunkInFreeLists(ffc), | |
| 8266 "free range is not in free lists"); | |
| 8267 } | |
| 8268 _sp->removeFreeChunkFromFreeLists(ffc); | |
| 8269 set_freeRangeInFreeLists(false); | |
| 8270 } | |
| 8271 set_lastFreeRangeCoalesced(true); | |
| 8272 } | |
| 8273 // this will be swept up when we hit the end of the free range | |
| 8274 | |
| 8275 // Verify that the bit map has no bits marked between | |
| 8276 // addr and purported end of just dead object. | |
| 8277 _bitMap->verifyNoOneBitsInRange(addr + 1, addr + size); | |
| 8278 } | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8279 assert(_limit >= addr + size, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8280 "A freshly garbage chunk can't possibly straddle over _limit"); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8281 if (inFreeRange()) lookahead_and_flush(fc, size); |
| 0 | 8282 return size; |
| 8283 } | |
| 8284 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8285 size_t SweepClosure::do_live_chunk(FreeChunk* fc) { |
| 0 | 8286 HeapWord* addr = (HeapWord*) fc; |
| 8287 // The sweeper has just found a live object. Return any accumulated | |
| 8288 // left hand chunk to the free lists. | |
| 8289 if (inFreeRange()) { | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8290 assert(freeFinger() < addr, "freeFinger points too high"); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8291 flush_cur_free_chunk(freeFinger(), pointer_delta(addr, freeFinger())); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8292 } |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8293 |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8294 // This object is live: we'd normally expect this to be |
| 0 | 8295 // an oop, and like to assert the following: |
| 8296 // assert(oop(addr)->is_oop(), "live block should be an oop"); | |
| 8297 // However, as we commented above, this may be an object whose | |
| 8298 // header hasn't yet been initialized. | |
| 8299 size_t size; | |
| 8300 assert(_bitMap->isMarked(addr), "Tautology for this control point"); | |
| 8301 if (_bitMap->isMarked(addr + 1)) { | |
| 8302 // Determine the size from the bit map, rather than trying to | |
| 8303 // compute it from the object header. | |
| 8304 HeapWord* nextOneAddr = _bitMap->getNextMarkedWordAddress(addr + 2); | |
| 8305 size = pointer_delta(nextOneAddr + 1, addr); | |
| 8306 assert(size == CompactibleFreeListSpace::adjustObjectSize(size), | |
| 8307 "alignment problem"); | |
| 8308 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8309 #ifdef DEBUG |
| 187 | 8310 if (oop(addr)->klass_or_null() != NULL && |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
8311 ( !_collector->should_unload_classes() |
|
518
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8312 || (oop(addr)->is_parsable()) && |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8313 oop(addr)->is_conc_safe())) { |
| 0 | 8314 // Ignore mark word because we are running concurrent with mutators |
| 8315 assert(oop(addr)->is_oop(true), "live block should be an oop"); | |
|
518
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8316 // is_conc_safe is checked before performing this assertion |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8317 // because an object that is not is_conc_safe may yet have |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8318 // the return from size() correct. |
| 0 | 8319 assert(size == |
| 8320 CompactibleFreeListSpace::adjustObjectSize(oop(addr)->size()), | |
| 8321 "P-mark and computed size do not agree"); | |
| 8322 } | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8323 #endif |
| 0 | 8324 |
| 8325 } else { | |
| 8326 // This should be an initialized object that's alive. | |
| 187 | 8327 assert(oop(addr)->klass_or_null() != NULL && |
|
94
0834225a7916
6634032: CMS: Need CMSInitiatingPermOccupancyFraction for perm, divorcing from CMSInitiatingOccupancyFraction
ysr
parents:
9
diff
changeset
|
8328 (!_collector->should_unload_classes() |
| 0 | 8329 || oop(addr)->is_parsable()), |
| 8330 "Should be an initialized object"); | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8331 // Note that there are objects used during class redefinition, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8332 // e.g. merge_cp in VM_RedefineClasses::merge_cp_and_rewrite(), |
|
518
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8333 // which are discarded with their is_conc_safe state still |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8334 // false. These object may be floating garbage so may be |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8335 // seen here. If they are floating garbage their size |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8336 // should be attainable from their klass. Do not that |
|
0af8b0718fc9
6692899: CMS: many vm.parallel_class_loading tests fail with assert "missing Printezis mark"
jmasa
parents:
517
diff
changeset
|
8337 // is_conc_safe() is true for oop(addr). |
| 0 | 8338 // Ignore mark word because we are running concurrent with mutators |
| 8339 assert(oop(addr)->is_oop(true), "live block should be an oop"); | |
| 8340 // Verify that the bit map has no bits marked between | |
| 8341 // addr and purported end of this block. | |
| 8342 size = CompactibleFreeListSpace::adjustObjectSize(oop(addr)->size()); | |
| 8343 assert(size >= 3, "Necessary for Printezis marks to work"); | |
| 8344 assert(!_bitMap->isMarked(addr+1), "Tautology for this control point"); | |
| 8345 DEBUG_ONLY(_bitMap->verifyNoOneBitsInRange(addr+2, addr+size);) | |
| 8346 } | |
| 8347 return size; | |
| 8348 } | |
| 8349 | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8350 void SweepClosure::do_post_free_or_garbage_chunk(FreeChunk* fc, |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8351 size_t chunkSize) { |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8352 // do_post_free_or_garbage_chunk() should only be called in the case |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8353 // of the adaptive free list allocator. |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8354 const bool fcInFreeLists = fc->isFree(); |
| 0 | 8355 assert(_sp->adaptive_freelists(), "Should only be used in this case."); |
| 8356 assert((HeapWord*)fc <= _limit, "sweep invariant"); | |
| 8357 if (CMSTestInFreeList && fcInFreeLists) { | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8358 assert(_sp->verifyChunkInFreeLists(fc), "free chunk is not in free lists"); |
|
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8359 } |
| 0 | 8360 |
| 8361 if (CMSTraceSweeper) { | |
| 8362 gclog_or_tty->print_cr(" -- pick up another chunk at 0x%x (%d)", fc, chunkSize); | |
| 8363 } | |
| 8364 | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8365 HeapWord* const fc_addr = (HeapWord*) fc; |
| 0 | 8366 |
| 8367 bool coalesce; | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8368 const size_t left = pointer_delta(fc_addr, freeFinger()); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8369 const size_t right = chunkSize; |
| 0 | 8370 switch (FLSCoalescePolicy) { |
| 8371 // numeric value forms a coalition aggressiveness metric | |
| 8372 case 0: { // never coalesce | |
| 8373 coalesce = false; | |
| 8374 break; | |
| 8375 } | |
| 8376 case 1: { // coalesce if left & right chunks on overpopulated lists | |
| 8377 coalesce = _sp->coalOverPopulated(left) && | |
| 8378 _sp->coalOverPopulated(right); | |
| 8379 break; | |
| 8380 } | |
| 8381 case 2: { // coalesce if left chunk on overpopulated list (default) | |
| 8382 coalesce = _sp->coalOverPopulated(left); | |
| 8383 break; | |
| 8384 } | |
| 8385 case 3: { // coalesce if left OR right chunk on overpopulated list | |
| 8386 coalesce = _sp->coalOverPopulated(left) || | |
| 8387 _sp->coalOverPopulated(right); | |
| 8388 break; | |
| 8389 } | |
| 8390 case 4: { // always coalesce | |
| 8391 coalesce = true; | |
| 8392 break; | |
| 8393 } | |
| 8394 default: | |
| 8395 ShouldNotReachHere(); | |
| 8396 } | |
| 8397 | |
| 8398 // Should the current free range be coalesced? | |
| 8399 // If the chunk is in a free range and either we decided to coalesce above | |
| 8400 // or the chunk is near the large block at the end of the heap | |
| 8401 // (isNearLargestChunk() returns true), then coalesce this chunk. | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8402 const bool doCoalesce = inFreeRange() |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8403 && (coalesce || _g->isNearLargestChunk(fc_addr)); |
| 0 | 8404 if (doCoalesce) { |
| 8405 // Coalesce the current free range on the left with the new | |
| 8406 // chunk on the right. If either is on a free list, | |
| 8407 // it must be removed from the list and stashed in the closure. | |
| 8408 if (freeRangeInFreeLists()) { | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8409 FreeChunk* const ffc = (FreeChunk*)freeFinger(); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8410 assert(ffc->size() == pointer_delta(fc_addr, freeFinger()), |
| 0 | 8411 "Size of free range is inconsistent with chunk size."); |
| 8412 if (CMSTestInFreeList) { | |
| 8413 assert(_sp->verifyChunkInFreeLists(ffc), | |
| 8414 "Chunk is not in free lists"); | |
| 8415 } | |
| 8416 _sp->coalDeath(ffc->size()); | |
| 8417 _sp->removeFreeChunkFromFreeLists(ffc); | |
| 8418 set_freeRangeInFreeLists(false); | |
| 8419 } | |
| 8420 if (fcInFreeLists) { | |
| 8421 _sp->coalDeath(chunkSize); | |
| 8422 assert(fc->size() == chunkSize, | |
| 8423 "The chunk has the wrong size or is not in the free lists"); | |
| 8424 _sp->removeFreeChunkFromFreeLists(fc); | |
| 8425 } | |
| 8426 set_lastFreeRangeCoalesced(true); | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8427 print_free_block_coalesced(fc); |
| 0 | 8428 } else { // not in a free range and/or should not coalesce |
| 8429 // Return the current free range and start a new one. | |
| 8430 if (inFreeRange()) { | |
| 8431 // In a free range but cannot coalesce with the right hand chunk. | |
| 8432 // Put the current free range into the free lists. | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8433 flush_cur_free_chunk(freeFinger(), |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8434 pointer_delta(fc_addr, freeFinger())); |
| 0 | 8435 } |
| 8436 // Set up for new free range. Pass along whether the right hand | |
| 8437 // chunk is in the free lists. | |
| 8438 initialize_free_range((HeapWord*)fc, fcInFreeLists); | |
| 8439 } | |
| 8440 } | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8441 |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8442 // Lookahead flush: |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8443 // If we are tracking a free range, and this is the last chunk that |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8444 // we'll look at because its end crosses past _limit, we'll preemptively |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8445 // flush it along with any free range we may be holding on to. Note that |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8446 // this can be the case only for an already free or freshly garbage |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8447 // chunk. If this block is an object, it can never straddle |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8448 // over _limit. The "straddling" occurs when _limit is set at |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8449 // the previous end of the space when this cycle started, and |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8450 // a subsequent heap expansion caused the previously co-terminal |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8451 // free block to be coalesced with the newly expanded portion, |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8452 // thus rendering _limit a non-block-boundary making it dangerous |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8453 // for the sweeper to step over and examine. |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8454 void SweepClosure::lookahead_and_flush(FreeChunk* fc, size_t chunk_size) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8455 assert(inFreeRange(), "Should only be called if currently in a free range."); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8456 HeapWord* const eob = ((HeapWord*)fc) + chunk_size; |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8457 assert(_sp->used_region().contains(eob - 1), |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8458 err_msg("eob = " PTR_FORMAT " out of bounds wrt _sp = [" PTR_FORMAT "," PTR_FORMAT ")" |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8459 " when examining fc = " PTR_FORMAT "(" SIZE_FORMAT ")", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8460 _limit, _sp->bottom(), _sp->end(), fc, chunk_size)); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8461 if (eob >= _limit) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8462 assert(eob == _limit || fc->isFree(), "Only a free chunk should allow us to cross over the limit"); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8463 if (CMSTraceSweeper) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8464 gclog_or_tty->print_cr("_limit " PTR_FORMAT " reached or crossed by block " |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8465 "[" PTR_FORMAT "," PTR_FORMAT ") in space " |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8466 "[" PTR_FORMAT "," PTR_FORMAT ")", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8467 _limit, fc, eob, _sp->bottom(), _sp->end()); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8468 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8469 // Return the storage we are tracking back into the free lists. |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8470 if (CMSTraceSweeper) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8471 gclog_or_tty->print_cr("Flushing ... "); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8472 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8473 assert(freeFinger() < eob, "Error"); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8474 flush_cur_free_chunk( freeFinger(), pointer_delta(eob, freeFinger())); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8475 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8476 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8477 |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8478 void SweepClosure::flush_cur_free_chunk(HeapWord* chunk, size_t size) { |
| 0 | 8479 assert(inFreeRange(), "Should only be called if currently in a free range."); |
| 8480 assert(size > 0, | |
| 8481 "A zero sized chunk cannot be added to the free lists."); | |
| 8482 if (!freeRangeInFreeLists()) { | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8483 if (CMSTestInFreeList) { |
| 0 | 8484 FreeChunk* fc = (FreeChunk*) chunk; |
| 8485 fc->setSize(size); | |
| 8486 assert(!_sp->verifyChunkInFreeLists(fc), | |
| 8487 "chunk should not be in free lists yet"); | |
| 8488 } | |
| 8489 if (CMSTraceSweeper) { | |
| 8490 gclog_or_tty->print_cr(" -- add free block 0x%x (%d) to free lists", | |
| 8491 chunk, size); | |
| 8492 } | |
| 8493 // A new free range is going to be starting. The current | |
| 8494 // free range has not been added to the free lists yet or | |
| 8495 // was removed so add it back. | |
| 8496 // If the current free range was coalesced, then the death | |
| 8497 // of the free range was recorded. Record a birth now. | |
| 8498 if (lastFreeRangeCoalesced()) { | |
| 8499 _sp->coalBirth(size); | |
| 8500 } | |
| 8501 _sp->addChunkAndRepairOffsetTable(chunk, size, | |
| 8502 lastFreeRangeCoalesced()); | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8503 } else if (CMSTraceSweeper) { |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8504 gclog_or_tty->print_cr("Already in free list: nothing to flush"); |
| 0 | 8505 } |
| 8506 set_inFreeRange(false); | |
| 8507 set_freeRangeInFreeLists(false); | |
| 8508 } | |
| 8509 | |
| 8510 // We take a break if we've been at this for a while, | |
| 8511 // so as to avoid monopolizing the locks involved. | |
| 8512 void SweepClosure::do_yield_work(HeapWord* addr) { | |
| 8513 // Return current free chunk being used for coalescing (if any) | |
| 8514 // to the appropriate freelist. After yielding, the next | |
| 8515 // free block encountered will start a coalescing range of | |
| 8516 // free blocks. If the next free block is adjacent to the | |
| 8517 // chunk just flushed, they will need to wait for the next | |
| 8518 // sweep to be coalesced. | |
| 8519 if (inFreeRange()) { | |
|
2132
4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
ysr
parents:
1994
diff
changeset
|
8520 flush_cur_free_chunk(freeFinger(), pointer_delta(addr, freeFinger())); |
| 0 | 8521 } |
| 8522 | |
| 8523 // First give up the locks, then yield, then re-lock. | |
| 8524 // We should probably use a constructor/destructor idiom to | |
| 8525 // do this unlock/lock or modify the MutexUnlocker class to | |
| 8526 // serve our purpose. XXX | |
| 8527 assert_lock_strong(_bitMap->lock()); | |
| 8528 assert_lock_strong(_freelistLock); | |
| 8529 assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(), | |
| 8530 "CMS thread should hold CMS token"); | |
| 8531 _bitMap->lock()->unlock(); | |
| 8532 _freelistLock->unlock(); | |
| 8533 ConcurrentMarkSweepThread::desynchronize(true); | |
| 8534 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 8535 _collector->stopTimer(); | |
| 8536 GCPauseTimer p(_collector->size_policy()->concurrent_timer_ptr()); | |
| 8537 if (PrintCMSStatistics != 0) { | |
| 8538 _collector->incrementYields(); | |
| 8539 } | |
| 8540 _collector->icms_wait(); | |
| 8541 | |
| 8542 // See the comment in coordinator_yield() | |
| 8543 for (unsigned i = 0; i < CMSYieldSleepCount && | |
| 8544 ConcurrentMarkSweepThread::should_yield() && | |
| 8545 !CMSCollector::foregroundGCIsActive(); ++i) { | |
| 8546 os::sleep(Thread::current(), 1, false); | |
| 8547 ConcurrentMarkSweepThread::acknowledge_yield_request(); | |
| 8548 } | |
| 8549 | |
| 8550 ConcurrentMarkSweepThread::synchronize(true); | |
| 8551 _freelistLock->lock(); | |
| 8552 _bitMap->lock()->lock_without_safepoint_check(); | |
| 8553 _collector->startTimer(); | |
| 8554 } | |
| 8555 | |
| 8556 #ifndef PRODUCT | |
| 8557 // This is actually very useful in a product build if it can | |
| 8558 // be called from the debugger. Compile it into the product | |
| 8559 // as needed. | |
| 8560 bool debug_verifyChunkInFreeLists(FreeChunk* fc) { | |
| 8561 return debug_cms_space->verifyChunkInFreeLists(fc); | |
| 8562 } | |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8563 #endif |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8564 |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8565 void SweepClosure::print_free_block_coalesced(FreeChunk* fc) const { |
| 0 | 8566 if (CMSTraceSweeper) { |
|
3746
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8567 gclog_or_tty->print_cr("Sweep:coal_free_blk " PTR_FORMAT " (" SIZE_FORMAT ")", |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8568 fc, fc->size()); |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8569 } |
|
537a4053b0f9
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
ysr
parents:
3356
diff
changeset
|
8570 } |
| 0 | 8571 |
| 8572 // CMSIsAliveClosure | |
| 8573 bool CMSIsAliveClosure::do_object_b(oop obj) { | |
| 8574 HeapWord* addr = (HeapWord*)obj; | |
| 8575 return addr != NULL && | |
| 8576 (!_span.contains(addr) || _bit_map->isMarked(addr)); | |
| 8577 } | |
| 8578 | |
| 935 | 8579 CMSKeepAliveClosure::CMSKeepAliveClosure( CMSCollector* collector, |
| 8580 MemRegion span, | |
| 8581 CMSBitMap* bit_map, CMSMarkStack* mark_stack, | |
| 8582 CMSMarkStack* revisit_stack, bool cpc): | |
| 8583 KlassRememberingOopClosure(collector, NULL, revisit_stack), | |
| 8584 _span(span), | |
| 8585 _bit_map(bit_map), | |
| 8586 _mark_stack(mark_stack), | |
| 8587 _concurrent_precleaning(cpc) { | |
| 8588 assert(!_span.is_empty(), "Empty span could spell trouble"); | |
| 8589 } | |
| 8590 | |
| 8591 | |
| 0 | 8592 // CMSKeepAliveClosure: the serial version |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8593 void CMSKeepAliveClosure::do_oop(oop obj) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8594 HeapWord* addr = (HeapWord*)obj; |
| 0 | 8595 if (_span.contains(addr) && |
| 8596 !_bit_map->isMarked(addr)) { | |
| 8597 _bit_map->mark(addr); | |
| 8598 bool simulate_overflow = false; | |
| 8599 NOT_PRODUCT( | |
| 8600 if (CMSMarkStackOverflowALot && | |
| 8601 _collector->simulate_overflow()) { | |
| 8602 // simulate a stack overflow | |
| 8603 simulate_overflow = true; | |
| 8604 } | |
| 8605 ) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8606 if (simulate_overflow || !_mark_stack->push(obj)) { |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8607 if (_concurrent_precleaning) { |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8608 // We dirty the overflown object and let the remark |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8609 // phase deal with it. |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8610 assert(_collector->overflow_list_is_empty(), "Error"); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8611 // In the case of object arrays, we need to dirty all of |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8612 // the cards that the object spans. No locking or atomics |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8613 // are needed since no one else can be mutating the mod union |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8614 // table. |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8615 if (obj->is_objArray()) { |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8616 size_t sz = obj->size(); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8617 HeapWord* end_card_addr = |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8618 (HeapWord*)round_to((intptr_t)(addr+sz), CardTableModRefBS::card_size); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8619 MemRegion redirty_range = MemRegion(addr, end_card_addr); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8620 assert(!redirty_range.is_empty(), "Arithmetical tautology"); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8621 _collector->_modUnionTable.mark_range(redirty_range); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8622 } else { |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8623 _collector->_modUnionTable.mark(addr); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8624 } |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8625 _collector->_ser_kac_preclean_ovflw++; |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8626 } else { |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8627 _collector->push_on_overflow_list(obj); |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8628 _collector->_ser_kac_ovflw++; |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8629 } |
| 0 | 8630 } |
| 8631 } | |
| 8632 } | |
| 8633 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8634 void CMSKeepAliveClosure::do_oop(oop* p) { CMSKeepAliveClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8635 void CMSKeepAliveClosure::do_oop(narrowOop* p) { CMSKeepAliveClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8636 |
| 0 | 8637 // CMSParKeepAliveClosure: a parallel version of the above. |
| 8638 // The work queues are private to each closure (thread), | |
| 8639 // but (may be) available for stealing by other threads. | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8640 void CMSParKeepAliveClosure::do_oop(oop obj) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8641 HeapWord* addr = (HeapWord*)obj; |
| 0 | 8642 if (_span.contains(addr) && |
| 8643 !_bit_map->isMarked(addr)) { | |
| 8644 // In general, during recursive tracing, several threads | |
| 8645 // may be concurrently getting here; the first one to | |
| 8646 // "tag" it, claims it. | |
| 8647 if (_bit_map->par_mark(addr)) { | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8648 bool res = _work_queue->push(obj); |
| 0 | 8649 assert(res, "Low water mark should be much less than capacity"); |
| 8650 // Do a recursive trim in the hope that this will keep | |
| 8651 // stack usage lower, but leave some oops for potential stealers | |
| 8652 trim_queue(_low_water_mark); | |
| 8653 } // Else, another thread got there first | |
| 8654 } | |
| 8655 } | |
| 8656 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8657 void CMSParKeepAliveClosure::do_oop(oop* p) { CMSParKeepAliveClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8658 void CMSParKeepAliveClosure::do_oop(narrowOop* p) { CMSParKeepAliveClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8659 |
| 0 | 8660 void CMSParKeepAliveClosure::trim_queue(uint max) { |
| 8661 while (_work_queue->size() > max) { | |
| 8662 oop new_oop; | |
| 8663 if (_work_queue->pop_local(new_oop)) { | |
| 8664 assert(new_oop != NULL && new_oop->is_oop(), "Expected an oop"); | |
| 8665 assert(_bit_map->isMarked((HeapWord*)new_oop), | |
| 8666 "no white objects on this stack!"); | |
| 8667 assert(_span.contains((HeapWord*)new_oop), "Out of bounds oop"); | |
| 8668 // iterate over the oops in this oop, marking and pushing | |
| 8669 // the ones in CMS heap (i.e. in _span). | |
| 8670 new_oop->oop_iterate(&_mark_and_push); | |
| 8671 } | |
| 8672 } | |
| 8673 } | |
| 8674 | |
| 935 | 8675 CMSInnerParMarkAndPushClosure::CMSInnerParMarkAndPushClosure( |
| 8676 CMSCollector* collector, | |
| 8677 MemRegion span, CMSBitMap* bit_map, | |
| 8678 CMSMarkStack* revisit_stack, | |
| 8679 OopTaskQueue* work_queue): | |
| 8680 Par_KlassRememberingOopClosure(collector, NULL, revisit_stack), | |
| 8681 _span(span), | |
| 8682 _bit_map(bit_map), | |
| 8683 _work_queue(work_queue) { } | |
| 8684 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8685 void CMSInnerParMarkAndPushClosure::do_oop(oop obj) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8686 HeapWord* addr = (HeapWord*)obj; |
| 0 | 8687 if (_span.contains(addr) && |
| 8688 !_bit_map->isMarked(addr)) { | |
| 8689 if (_bit_map->par_mark(addr)) { | |
| 8690 bool simulate_overflow = false; | |
| 8691 NOT_PRODUCT( | |
| 8692 if (CMSMarkStackOverflowALot && | |
| 8693 _collector->par_simulate_overflow()) { | |
| 8694 // simulate a stack overflow | |
| 8695 simulate_overflow = true; | |
| 8696 } | |
| 8697 ) | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8698 if (simulate_overflow || !_work_queue->push(obj)) { |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8699 _collector->par_push_on_overflow_list(obj); |
| 0 | 8700 _collector->_par_kac_ovflw++; |
| 8701 } | |
| 8702 } // Else another thread got there already | |
| 8703 } | |
| 8704 } | |
| 8705 | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8706 void CMSInnerParMarkAndPushClosure::do_oop(oop* p) { CMSInnerParMarkAndPushClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8707 void CMSInnerParMarkAndPushClosure::do_oop(narrowOop* p) { CMSInnerParMarkAndPushClosure::do_oop_work(p); } |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8708 |
| 0 | 8709 ////////////////////////////////////////////////////////////////// |
| 8710 // CMSExpansionCause ///////////////////////////// | |
| 8711 ////////////////////////////////////////////////////////////////// | |
| 8712 const char* CMSExpansionCause::to_string(CMSExpansionCause::Cause cause) { | |
| 8713 switch (cause) { | |
| 8714 case _no_expansion: | |
| 8715 return "No expansion"; | |
| 8716 case _satisfy_free_ratio: | |
| 8717 return "Free ratio"; | |
| 8718 case _satisfy_promotion: | |
| 8719 return "Satisfy promotion"; | |
| 8720 case _satisfy_allocation: | |
| 8721 return "allocation"; | |
| 8722 case _allocate_par_lab: | |
| 8723 return "Par LAB"; | |
| 8724 case _allocate_par_spooling_space: | |
| 8725 return "Par Spooling Space"; | |
| 8726 case _adaptive_size_policy: | |
| 8727 return "Ergonomics"; | |
| 8728 default: | |
| 8729 return "unknown"; | |
| 8730 } | |
| 8731 } | |
| 8732 | |
| 8733 void CMSDrainMarkingStackClosure::do_void() { | |
| 8734 // the max number to take from overflow list at a time | |
| 8735 const size_t num = _mark_stack->capacity()/4; | |
|
452
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8736 assert(!_concurrent_precleaning || _collector->overflow_list_is_empty(), |
|
00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents:
360
diff
changeset
|
8737 "Overflow list should be NULL during concurrent phases"); |
| 0 | 8738 while (!_mark_stack->isEmpty() || |
| 8739 // if stack is empty, check the overflow list | |
| 8740 _collector->take_from_overflow_list(num, _mark_stack)) { | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8741 oop obj = _mark_stack->pop(); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8742 HeapWord* addr = (HeapWord*)obj; |
| 0 | 8743 assert(_span.contains(addr), "Should be within span"); |
| 8744 assert(_bit_map->isMarked(addr), "Should be marked"); | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8745 assert(obj->is_oop(), "Should be an oop"); |
|
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
94
diff
changeset
|
8746 obj->oop_iterate(_keep_alive); |
| 0 | 8747 } |
| 8748 } | |
| 8749 | |
| 8750 void CMSParDrainMarkingStackClosure::do_void() { | |
| 8751 // drain queue | |
| 8752 trim_queue(0); | |
| 8753 } | |
| 8754 | |
| 8755 // Trim our work_queue so its length is below max at return | |
| 8756 void CMSParDrainMarkingStackClosure::trim_queue(uint max) { | |
| 8757 while (_work_queue->size() > max) { | |
| 8758 oop new_oop; | |
| 8759 if (_work_queue->pop_local(new_oop)) { | |
| 8760 assert(new_oop->is_oop(), "Expected an oop"); | |
| 8761 assert(_bit_map->isMarked((HeapWord*)new_oop), | |
| 8762 "no white objects on this stack!"); | |
| 8763 assert(_span.contains((HeapWord*)new_oop), "Out of bounds oop"); | |
| 8764 // iterate over the oops in this oop, marking and pushing | |
| 8765 // the ones in CMS heap (i.e. in _span). | |
| 8766 new_oop->oop_iterate(&_mark_and_push); | |
| 8767 } | |
| 8768 } | |
| 8769 } | |
| 8770 | |
| 8771 //////////////////////////////////////////////////////////////////// | |
| 8772 // Support for Marking Stack Overflow list handling and related code | |
| 8773 //////////////////////////////////////////////////////////////////// | |
| 8774 // Much of the following code is similar in shape and spirit to the | |
| 8775 // code used in ParNewGC. We should try and share that code | |
| 8776 // as much as possible in the future. | |
| 8777 | |
| 8778 #ifndef PRODUCT | |
| 8779 // Debugging support for CMSStackOverflowALot | |
| 8780 | |
| 8781 // It's OK to call this multi-threaded; the worst thing | |
| 8782 // that can happen is that we'll get a bunch of closely | |
| 8783 // spaced simulated oveflows, but that's OK, in fact | |
| 8784 // probably good as it would exercise the overflow code | |
| 8785 // under contention. | |
| 8786 bool CMSCollector::simulate_overflow() { | |
| 8787 if (_overflow_counter-- <= 0) { // just being defensive | |
| 8788 _overflow_counter = CMSMarkStackOverflowInterval; | |
| 8789 return true; | |
| 8790 } else { | |
| 8791 return false; | |
| 8792 } | |
| 8793 } | |
| 8794 | |
| 8795 bool CMSCollector::par_simulate_overflow() { | |
| 8796 return simulate_overflow(); | |
| 8797 } | |
| 8798 #endif | |
| 8799 | |
| 8800 // Single-threaded | |
| 8801 bool CMSCollector::take_from_overflow_list(size_t num, CMSMarkStack* stack) { | |
| 8802 assert(stack->isEmpty(), "Expected precondition"); | |
| 8803 assert(stack->capacity() > num, "Shouldn't bite more than can chew"); | |
| 8804 size_t i = num; | |
| 8805 oop cur = _overflow_list; | |
| 8806 const markOop proto = markOopDesc::prototype(); | |
| 534 | 8807 NOT_PRODUCT(ssize_t n = 0;) |
| 0 | 8808 for (oop next; i > 0 && cur != NULL; cur = next, i--) { |
| 8809 next = oop(cur->mark()); | |
| 8810 cur->set_mark(proto); // until proven otherwise | |
| 8811 assert(cur->is_oop(), "Should be an oop"); | |
| 8812 bool res = stack->push(cur); | |
| 8813 assert(res, "Bit off more than can chew?"); | |
| 8814 NOT_PRODUCT(n++;) | |
| 8815 } | |
| 8816 _overflow_list = cur; | |
| 8817 #ifndef PRODUCT | |
| 8818 assert(_num_par_pushes >= n, "Too many pops?"); | |
| 8819 _num_par_pushes -=n; | |
| 8820 #endif | |
| 8821 return !stack->isEmpty(); | |
| 8822 } | |
| 8823 | |
| 534 | 8824 #define BUSY (oop(0x1aff1aff)) |
| 8825 // (MT-safe) Get a prefix of at most "num" from the list. | |
| 8826 // The overflow list is chained through the mark word of | |
| 8827 // each object in the list. We fetch the entire list, | |
| 8828 // break off a prefix of the right size and return the | |
| 8829 // remainder. If other threads try to take objects from | |
| 8830 // the overflow list at that time, they will wait for | |
| 8831 // some time to see if data becomes available. If (and | |
| 8832 // only if) another thread places one or more object(s) | |
| 8833 // on the global list before we have returned the suffix | |
| 8834 // to the global list, we will walk down our local list | |
| 8835 // to find its end and append the global list to | |
| 8836 // our suffix before returning it. This suffix walk can | |
| 8837 // prove to be expensive (quadratic in the amount of traffic) | |
| 8838 // when there are many objects in the overflow list and | |
| 8839 // there is much producer-consumer contention on the list. | |
| 8840 // *NOTE*: The overflow list manipulation code here and | |
| 8841 // in ParNewGeneration:: are very similar in shape, | |
| 8842 // except that in the ParNew case we use the old (from/eden) | |
| 8843 // copy of the object to thread the list via its klass word. | |
| 8844 // Because of the common code, if you make any changes in | |
| 8845 // the code below, please check the ParNew version to see if | |
| 8846 // similar changes might be needed. | |
| 8847 // CR 6797058 has been filed to consolidate the common code. | |
| 0 | 8848 bool CMSCollector::par_take_from_overflow_list(size_t num, |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
8849 OopTaskQueue* work_q, |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
8850 int no_of_gc_threads) { |
| 534 | 8851 assert(work_q->size() == 0, "First empty local work queue"); |
| 0 | 8852 assert(num < work_q->max_elems(), "Can't bite more than we can chew"); |
| 8853 if (_overflow_list == NULL) { | |
| 8854 return false; | |
| 8855 } | |
| 8856 // Grab the entire list; we'll put back a suffix | |
| 534 | 8857 oop prefix = (oop)Atomic::xchg_ptr(BUSY, &_overflow_list); |
| 8858 Thread* tid = Thread::current(); | |
|
1833
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
8859 // Before "no_of_gc_threads" was introduced CMSOverflowSpinCount was |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
8860 // set to ParallelGCThreads. |
|
8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
8861 size_t CMSOverflowSpinCount = (size_t) no_of_gc_threads; // was ParallelGCThreads; |
| 534 | 8862 size_t sleep_time_millis = MAX2((size_t)1, num/100); |
| 8863 // If the list is busy, we spin for a short while, | |
| 8864 // sleeping between attempts to get the list. | |
| 8865 for (size_t spin = 0; prefix == BUSY && spin < CMSOverflowSpinCount; spin++) { | |
| 8866 os::sleep(tid, sleep_time_millis, false); | |
| 8867 if (_overflow_list == NULL) { | |
| 8868 // Nothing left to take | |
| 8869 return false; | |
| 8870 } else if (_overflow_list != BUSY) { | |
| 8871 // Try and grab the prefix | |
| 8872 prefix = (oop)Atomic::xchg_ptr(BUSY, &_overflow_list); | |
| 8873 } | |
| 8874 } | |
| 8875 // If the list was found to be empty, or we spun long | |
| 8876 // enough, we give up and return empty-handed. If we leave | |
| 8877 // the list in the BUSY state below, it must be the case that | |
| 8878 // some other thread holds the overflow list and will set it | |
| 8879 // to a non-BUSY state in the future. | |
| 8880 if (prefix == NULL || prefix == BUSY) { | |
| 8881 // Nothing to take or waited long enough | |
| 8882 if (prefix == NULL) { | |
| 8883 // Write back the NULL in case we overwrote it with BUSY above | |
| 8884 // and it is still the same value. | |
| 8885 (void) Atomic::cmpxchg_ptr(NULL, &_overflow_list, BUSY); | |
| 8886 } | |
| 8887 return false; | |
| 8888 } | |
| 8889 assert(prefix != NULL && prefix != BUSY, "Error"); | |
| 0 | 8890 size_t i = num; |
| 8891 oop cur = prefix; | |
| 534 | 8892 // Walk down the first "num" objects, unless we reach the end. |
| 0 | 8893 for (; i > 1 && cur->mark() != NULL; cur = oop(cur->mark()), i--); |
| 534 | 8894 if (cur->mark() == NULL) { |
| 8895 // We have "num" or fewer elements in the list, so there | |
| 8896 // is nothing to return to the global list. | |
| 8897 // Write back the NULL in lieu of the BUSY we wrote | |
| 8898 // above, if it is still the same value. | |
| 8899 if (_overflow_list == BUSY) { | |
| 8900 (void) Atomic::cmpxchg_ptr(NULL, &_overflow_list, BUSY); | |
| 8901 } | |
| 8902 } else { | |
| 8903 // Chop off the suffix and rerturn it to the global list. | |
| 8904 assert(cur->mark() != BUSY, "Error"); | |
| 0 | 8905 oop suffix_head = cur->mark(); // suffix will be put back on global list |
| 8906 cur->set_mark(NULL); // break off suffix | |
| 534 | 8907 // It's possible that the list is still in the empty(busy) state |
| 8908 // we left it in a short while ago; in that case we may be | |
| 8909 // able to place back the suffix without incurring the cost | |
| 8910 // of a walk down the list. | |
| 0 | 8911 oop observed_overflow_list = _overflow_list; |
| 534 | 8912 oop cur_overflow_list = observed_overflow_list; |
| 8913 bool attached = false; | |
| 8914 while (observed_overflow_list == BUSY || observed_overflow_list == NULL) { | |
| 0 | 8915 observed_overflow_list = |
| 534 | 8916 (oop) Atomic::cmpxchg_ptr(suffix_head, &_overflow_list, cur_overflow_list); |
| 8917 if (cur_overflow_list == observed_overflow_list) { | |
| 8918 attached = true; | |
| 8919 break; | |
| 8920 } else cur_overflow_list = observed_overflow_list; | |
| 8921 } | |
| 8922 if (!attached) { | |
| 8923 // Too bad, someone else sneaked in (at least) an element; we'll need | |
| 8924 // to do a splice. Find tail of suffix so we can prepend suffix to global | |
| 8925 // list. | |
| 8926 for (cur = suffix_head; cur->mark() != NULL; cur = (oop)(cur->mark())); | |
| 8927 oop suffix_tail = cur; | |
| 8928 assert(suffix_tail != NULL && suffix_tail->mark() == NULL, | |
| 8929 "Tautology"); | |
| 8930 observed_overflow_list = _overflow_list; | |
| 8931 do { | |
| 8932 cur_overflow_list = observed_overflow_list; | |
| 8933 if (cur_overflow_list != BUSY) { | |
| 8934 // Do the splice ... | |
| 8935 suffix_tail->set_mark(markOop(cur_overflow_list)); | |
| 8936 } else { // cur_overflow_list == BUSY | |
| 8937 suffix_tail->set_mark(NULL); | |
| 8938 } | |
| 8939 // ... and try to place spliced list back on overflow_list ... | |
| 8940 observed_overflow_list = | |
| 8941 (oop) Atomic::cmpxchg_ptr(suffix_head, &_overflow_list, cur_overflow_list); | |
| 8942 } while (cur_overflow_list != observed_overflow_list); | |
| 8943 // ... until we have succeeded in doing so. | |
| 8944 } | |
| 0 | 8945 } |
| 8946 | |
| 8947 // Push the prefix elements on work_q | |
| 8948 assert(prefix != NULL, "control point invariant"); | |
| 8949 const markOop proto = markOopDesc::prototype(); | |
| 8950 oop next; | |
| 534 | 8951 NOT_PRODUCT(ssize_t n = 0;) |
| 0 | 8952 for (cur = prefix; cur != NULL; cur = next) { |
| 8953 next = oop(cur->mark()); | |
| 8954 cur->set_mark(proto); // until proven otherwise | |
| 8955 assert(cur->is_oop(), "Should be an oop"); | |
| 8956 bool res = work_q->push(cur); | |
| 8957 assert(res, "Bit off more than we can chew?"); | |
| 8958 NOT_PRODUCT(n++;) | |
| 8959 } | |
| 8960 #ifndef PRODUCT | |
| 8961 assert(_num_par_pushes >= n, "Too many pops?"); | |
| 8962 Atomic::add_ptr(-(intptr_t)n, &_num_par_pushes); | |
| 8963 #endif | |
| 8964 return true; | |
| 8965 } | |
| 8966 | |
| 8967 // Single-threaded | |
| 8968 void CMSCollector::push_on_overflow_list(oop p) { | |
| 8969 NOT_PRODUCT(_num_par_pushes++;) | |
| 8970 assert(p->is_oop(), "Not an oop"); | |
| 8971 preserve_mark_if_necessary(p); | |
| 8972 p->set_mark((markOop)_overflow_list); | |
| 8973 _overflow_list = p; | |
| 8974 } | |
| 8975 | |
| 8976 // Multi-threaded; use CAS to prepend to overflow list | |
| 8977 void CMSCollector::par_push_on_overflow_list(oop p) { | |
| 8978 NOT_PRODUCT(Atomic::inc_ptr(&_num_par_pushes);) | |
| 8979 assert(p->is_oop(), "Not an oop"); | |
| 8980 par_preserve_mark_if_necessary(p); | |
| 8981 oop observed_overflow_list = _overflow_list; | |
| 8982 oop cur_overflow_list; | |
| 8983 do { | |
| 8984 cur_overflow_list = observed_overflow_list; | |
| 534 | 8985 if (cur_overflow_list != BUSY) { |
| 8986 p->set_mark(markOop(cur_overflow_list)); | |
| 8987 } else { | |
| 8988 p->set_mark(NULL); | |
| 8989 } | |
| 0 | 8990 observed_overflow_list = |
| 8991 (oop) Atomic::cmpxchg_ptr(p, &_overflow_list, cur_overflow_list); | |
| 8992 } while (cur_overflow_list != observed_overflow_list); | |
| 8993 } | |
| 534 | 8994 #undef BUSY |
| 0 | 8995 |
| 8996 // Single threaded | |
| 8997 // General Note on GrowableArray: pushes may silently fail | |
| 8998 // because we are (temporarily) out of C-heap for expanding | |
| 8999 // the stack. The problem is quite ubiquitous and affects | |
| 9000 // a lot of code in the JVM. The prudent thing for GrowableArray | |
| 9001 // to do (for now) is to exit with an error. However, that may | |
| 9002 // be too draconian in some cases because the caller may be | |
| 534 | 9003 // able to recover without much harm. For such cases, we |
| 0 | 9004 // should probably introduce a "soft_push" method which returns |
| 9005 // an indication of success or failure with the assumption that | |
| 9006 // the caller may be able to recover from a failure; code in | |
| 9007 // the VM can then be changed, incrementally, to deal with such | |
| 9008 // failures where possible, thus, incrementally hardening the VM | |
| 9009 // in such low resource situations. | |
| 9010 void CMSCollector::preserve_mark_work(oop p, markOop m) { | |
|
1836
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9011 _preserved_oop_stack.push(p); |
|
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9012 _preserved_mark_stack.push(m); |
| 0 | 9013 assert(m == p->mark(), "Mark word changed"); |
|
1836
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9014 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(), |
| 0 | 9015 "bijection"); |
| 9016 } | |
| 9017 | |
| 9018 // Single threaded | |
| 9019 void CMSCollector::preserve_mark_if_necessary(oop p) { | |
| 9020 markOop m = p->mark(); | |
| 9021 if (m->must_be_preserved(p)) { | |
| 9022 preserve_mark_work(p, m); | |
| 9023 } | |
| 9024 } | |
| 9025 | |
| 9026 void CMSCollector::par_preserve_mark_if_necessary(oop p) { | |
| 9027 markOop m = p->mark(); | |
| 9028 if (m->must_be_preserved(p)) { | |
| 9029 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 9030 // Even though we read the mark word without holding | |
| 9031 // the lock, we are assured that it will not change | |
| 9032 // because we "own" this oop, so no other thread can | |
| 9033 // be trying to push it on the overflow list; see | |
| 9034 // the assertion in preserve_mark_work() that checks | |
| 9035 // that m == p->mark(). | |
| 9036 preserve_mark_work(p, m); | |
| 9037 } | |
| 9038 } | |
| 9039 | |
| 9040 // We should be able to do this multi-threaded, | |
| 9041 // a chunk of stack being a task (this is | |
| 9042 // correct because each oop only ever appears | |
| 9043 // once in the overflow list. However, it's | |
| 9044 // not very easy to completely overlap this with | |
| 9045 // other operations, so will generally not be done | |
| 9046 // until all work's been completed. Because we | |
| 9047 // expect the preserved oop stack (set) to be small, | |
| 9048 // it's probably fine to do this single-threaded. | |
| 9049 // We can explore cleverer concurrent/overlapped/parallel | |
| 9050 // processing of preserved marks if we feel the | |
| 9051 // need for this in the future. Stack overflow should | |
| 9052 // be so rare in practice and, when it happens, its | |
| 9053 // effect on performance so great that this will | |
| 9054 // likely just be in the noise anyway. | |
| 9055 void CMSCollector::restore_preserved_marks_if_any() { | |
| 9056 assert(SafepointSynchronize::is_at_safepoint(), | |
| 9057 "world should be stopped"); | |
| 9058 assert(Thread::current()->is_ConcurrentGC_thread() || | |
| 9059 Thread::current()->is_VM_thread(), | |
| 9060 "should be single-threaded"); | |
|
1836
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9061 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(), |
|
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9062 "bijection"); |
|
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9063 |
|
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9064 while (!_preserved_oop_stack.is_empty()) { |
|
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9065 oop p = _preserved_oop_stack.pop(); |
| 0 | 9066 assert(p->is_oop(), "Should be an oop"); |
| 9067 assert(_span.contains(p), "oop should be in _span"); | |
| 9068 assert(p->mark() == markOopDesc::prototype(), | |
| 9069 "Set when taken from overflow list"); | |
|
1836
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9070 markOop m = _preserved_mark_stack.pop(); |
| 0 | 9071 p->set_mark(m); |
| 9072 } | |
|
1836
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9073 assert(_preserved_mark_stack.is_empty() && _preserved_oop_stack.is_empty(), |
| 0 | 9074 "stacks were cleared above"); |
| 9075 } | |
| 9076 | |
| 9077 #ifndef PRODUCT | |
| 9078 bool CMSCollector::no_preserved_marks() const { | |
|
1836
894b1d7c7e01
6423256: GC stacks should use a better data structure
jcoomes
parents:
1833
diff
changeset
|
9079 return _preserved_mark_stack.is_empty() && _preserved_oop_stack.is_empty(); |
| 0 | 9080 } |
| 9081 #endif | |
| 9082 | |
| 9083 CMSAdaptiveSizePolicy* ASConcurrentMarkSweepGeneration::cms_size_policy() const | |
| 9084 { | |
| 9085 GenCollectedHeap* gch = (GenCollectedHeap*) GenCollectedHeap::heap(); | |
| 9086 CMSAdaptiveSizePolicy* size_policy = | |
| 9087 (CMSAdaptiveSizePolicy*) gch->gen_policy()->size_policy(); | |
| 9088 assert(size_policy->is_gc_cms_adaptive_size_policy(), | |
| 9089 "Wrong type for size policy"); | |
| 9090 return size_policy; | |
| 9091 } | |
| 9092 | |
| 9093 void ASConcurrentMarkSweepGeneration::resize(size_t cur_promo_size, | |
| 9094 size_t desired_promo_size) { | |
| 9095 if (cur_promo_size < desired_promo_size) { | |
| 9096 size_t expand_bytes = desired_promo_size - cur_promo_size; | |
| 9097 if (PrintAdaptiveSizePolicy && Verbose) { | |
| 9098 gclog_or_tty->print_cr(" ASConcurrentMarkSweepGeneration::resize " | |
| 9099 "Expanding tenured generation by " SIZE_FORMAT " (bytes)", | |
| 9100 expand_bytes); | |
| 9101 } | |
| 9102 expand(expand_bytes, | |
| 9103 MinHeapDeltaBytes, | |
| 9104 CMSExpansionCause::_adaptive_size_policy); | |
| 9105 } else if (desired_promo_size < cur_promo_size) { | |
| 9106 size_t shrink_bytes = cur_promo_size - desired_promo_size; | |
| 9107 if (PrintAdaptiveSizePolicy && Verbose) { | |
| 9108 gclog_or_tty->print_cr(" ASConcurrentMarkSweepGeneration::resize " | |
| 9109 "Shrinking tenured generation by " SIZE_FORMAT " (bytes)", | |
| 9110 shrink_bytes); | |
| 9111 } | |
| 9112 shrink(shrink_bytes); | |
| 9113 } | |
| 9114 } | |
| 9115 | |
| 9116 CMSGCAdaptivePolicyCounters* ASConcurrentMarkSweepGeneration::gc_adaptive_policy_counters() { | |
| 9117 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 9118 CMSGCAdaptivePolicyCounters* counters = | |
| 9119 (CMSGCAdaptivePolicyCounters*) gch->collector_policy()->counters(); | |
| 9120 assert(counters->kind() == GCPolicyCounters::CMSGCAdaptivePolicyCountersKind, | |
| 9121 "Wrong kind of counters"); | |
| 9122 return counters; | |
| 9123 } | |
| 9124 | |
| 9125 | |
| 9126 void ASConcurrentMarkSweepGeneration::update_counters() { | |
| 9127 if (UsePerfData) { | |
| 9128 _space_counters->update_all(); | |
| 9129 _gen_counters->update_all(); | |
| 9130 CMSGCAdaptivePolicyCounters* counters = gc_adaptive_policy_counters(); | |
| 9131 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 9132 CMSGCStats* gc_stats_l = (CMSGCStats*) gc_stats(); | |
| 9133 assert(gc_stats_l->kind() == GCStats::CMSGCStatsKind, | |
| 9134 "Wrong gc statistics type"); | |
| 9135 counters->update_counters(gc_stats_l); | |
| 9136 } | |
| 9137 } | |
| 9138 | |
| 9139 void ASConcurrentMarkSweepGeneration::update_counters(size_t used) { | |
| 9140 if (UsePerfData) { | |
| 9141 _space_counters->update_used(used); | |
| 9142 _space_counters->update_capacity(); | |
| 9143 _gen_counters->update_all(); | |
| 9144 | |
| 9145 CMSGCAdaptivePolicyCounters* counters = gc_adaptive_policy_counters(); | |
| 9146 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 9147 CMSGCStats* gc_stats_l = (CMSGCStats*) gc_stats(); | |
| 9148 assert(gc_stats_l->kind() == GCStats::CMSGCStatsKind, | |
| 9149 "Wrong gc statistics type"); | |
| 9150 counters->update_counters(gc_stats_l); | |
| 9151 } | |
| 9152 } | |
| 9153 | |
| 9154 // The desired expansion delta is computed so that: | |
| 9155 // . desired free percentage or greater is used | |
| 9156 void ASConcurrentMarkSweepGeneration::compute_new_size() { | |
| 9157 assert_locked_or_safepoint(Heap_lock); | |
| 9158 | |
| 9159 GenCollectedHeap* gch = (GenCollectedHeap*) GenCollectedHeap::heap(); | |
| 9160 | |
| 9161 // If incremental collection failed, we just want to expand | |
| 9162 // to the limit. | |
| 9163 if (incremental_collection_failed()) { | |
| 9164 clear_incremental_collection_failed(); | |
| 9165 grow_to_reserved(); | |
| 9166 return; | |
| 9167 } | |
| 9168 | |
| 9169 assert(UseAdaptiveSizePolicy, "Should be using adaptive sizing"); | |
| 9170 | |
| 9171 assert(gch->kind() == CollectedHeap::GenCollectedHeap, | |
| 9172 "Wrong type of heap"); | |
| 9173 int prev_level = level() - 1; | |
| 9174 assert(prev_level >= 0, "The cms generation is the lowest generation"); | |
| 9175 Generation* prev_gen = gch->get_gen(prev_level); | |
| 9176 assert(prev_gen->kind() == Generation::ASParNew, | |
| 9177 "Wrong type of young generation"); | |
| 9178 ParNewGeneration* younger_gen = (ParNewGeneration*) prev_gen; | |
| 9179 size_t cur_eden = younger_gen->eden()->capacity(); | |
| 9180 CMSAdaptiveSizePolicy* size_policy = cms_size_policy(); | |
| 9181 size_t cur_promo = free(); | |
| 9182 size_policy->compute_tenured_generation_free_space(cur_promo, | |
| 9183 max_available(), | |
| 9184 cur_eden); | |
| 9185 resize(cur_promo, size_policy->promo_size()); | |
| 9186 | |
| 9187 // Record the new size of the space in the cms generation | |
| 9188 // that is available for promotions. This is temporary. | |
| 9189 // It should be the desired promo size. | |
| 9190 size_policy->avg_cms_promo()->sample(free()); | |
| 9191 size_policy->avg_old_live()->sample(used()); | |
| 9192 | |
| 9193 if (UsePerfData) { | |
| 9194 CMSGCAdaptivePolicyCounters* counters = gc_adaptive_policy_counters(); | |
| 9195 counters->update_cms_capacity_counter(capacity()); | |
| 9196 } | |
| 9197 } | |
| 9198 | |
| 9199 void ASConcurrentMarkSweepGeneration::shrink_by(size_t desired_bytes) { | |
| 9200 assert_locked_or_safepoint(Heap_lock); | |
| 9201 assert_lock_strong(freelistLock()); | |
| 9202 HeapWord* old_end = _cmsSpace->end(); | |
| 9203 HeapWord* unallocated_start = _cmsSpace->unallocated_block(); | |
| 9204 assert(old_end >= unallocated_start, "Miscalculation of unallocated_start"); | |
| 9205 FreeChunk* chunk_at_end = find_chunk_at_end(); | |
| 9206 if (chunk_at_end == NULL) { | |
| 9207 // No room to shrink | |
| 9208 if (PrintGCDetails && Verbose) { | |
| 9209 gclog_or_tty->print_cr("No room to shrink: old_end " | |
| 9210 PTR_FORMAT " unallocated_start " PTR_FORMAT | |
| 9211 " chunk_at_end " PTR_FORMAT, | |
| 9212 old_end, unallocated_start, chunk_at_end); | |
| 9213 } | |
| 9214 return; | |
| 9215 } else { | |
| 9216 | |
| 9217 // Find the chunk at the end of the space and determine | |
| 9218 // how much it can be shrunk. | |
| 9219 size_t shrinkable_size_in_bytes = chunk_at_end->size(); | |
| 9220 size_t aligned_shrinkable_size_in_bytes = | |
| 9221 align_size_down(shrinkable_size_in_bytes, os::vm_page_size()); | |
| 9222 assert(unallocated_start <= chunk_at_end->end(), | |
| 9223 "Inconsistent chunk at end of space"); | |
| 9224 size_t bytes = MIN2(desired_bytes, aligned_shrinkable_size_in_bytes); | |
| 9225 size_t word_size_before = heap_word_size(_virtual_space.committed_size()); | |
| 9226 | |
| 9227 // Shrink the underlying space | |
| 9228 _virtual_space.shrink_by(bytes); | |
| 9229 if (PrintGCDetails && Verbose) { | |
| 9230 gclog_or_tty->print_cr("ConcurrentMarkSweepGeneration::shrink_by:" | |
| 9231 " desired_bytes " SIZE_FORMAT | |
| 9232 " shrinkable_size_in_bytes " SIZE_FORMAT | |
| 9233 " aligned_shrinkable_size_in_bytes " SIZE_FORMAT | |
| 9234 " bytes " SIZE_FORMAT, | |
| 9235 desired_bytes, shrinkable_size_in_bytes, | |
| 9236 aligned_shrinkable_size_in_bytes, bytes); | |
| 9237 gclog_or_tty->print_cr(" old_end " SIZE_FORMAT | |
| 9238 " unallocated_start " SIZE_FORMAT, | |
| 9239 old_end, unallocated_start); | |
| 9240 } | |
| 9241 | |
| 9242 // If the space did shrink (shrinking is not guaranteed), | |
| 9243 // shrink the chunk at the end by the appropriate amount. | |
| 9244 if (((HeapWord*)_virtual_space.high()) < old_end) { | |
| 9245 size_t new_word_size = | |
| 9246 heap_word_size(_virtual_space.committed_size()); | |
| 9247 | |
| 9248 // Have to remove the chunk from the dictionary because it is changing | |
| 9249 // size and might be someplace elsewhere in the dictionary. | |
| 9250 | |
| 9251 // Get the chunk at end, shrink it, and put it | |
| 9252 // back. | |
| 9253 _cmsSpace->removeChunkFromDictionary(chunk_at_end); | |
| 9254 size_t word_size_change = word_size_before - new_word_size; | |
| 9255 size_t chunk_at_end_old_size = chunk_at_end->size(); | |
| 9256 assert(chunk_at_end_old_size >= word_size_change, | |
| 9257 "Shrink is too large"); | |
| 9258 chunk_at_end->setSize(chunk_at_end_old_size - | |
| 9259 word_size_change); | |
| 9260 _cmsSpace->freed((HeapWord*) chunk_at_end->end(), | |
| 9261 word_size_change); | |
| 9262 | |
| 9263 _cmsSpace->returnChunkToDictionary(chunk_at_end); | |
| 9264 | |
| 9265 MemRegion mr(_cmsSpace->bottom(), new_word_size); | |
| 9266 _bts->resize(new_word_size); // resize the block offset shared array | |
| 9267 Universe::heap()->barrier_set()->resize_covered_region(mr); | |
| 9268 _cmsSpace->assert_locked(); | |
| 9269 _cmsSpace->set_end((HeapWord*)_virtual_space.high()); | |
| 9270 | |
| 9271 NOT_PRODUCT(_cmsSpace->dictionary()->verify()); | |
| 9272 | |
| 9273 // update the space and generation capacity counters | |
| 9274 if (UsePerfData) { | |
| 9275 _space_counters->update_capacity(); | |
| 9276 _gen_counters->update_all(); | |
| 9277 } | |
| 9278 | |
| 9279 if (Verbose && PrintGCDetails) { | |
| 9280 size_t new_mem_size = _virtual_space.committed_size(); | |
| 9281 size_t old_mem_size = new_mem_size + bytes; | |
| 9282 gclog_or_tty->print_cr("Shrinking %s from %ldK by %ldK to %ldK", | |
| 9283 name(), old_mem_size/K, bytes/K, new_mem_size/K); | |
| 9284 } | |
| 9285 } | |
| 9286 | |
| 9287 assert(_cmsSpace->unallocated_block() <= _cmsSpace->end(), | |
| 9288 "Inconsistency at end of space"); | |
| 9289 assert(chunk_at_end->end() == _cmsSpace->end(), | |
| 9290 "Shrinking is inconsistent"); | |
| 9291 return; | |
| 9292 } | |
| 9293 } | |
| 9294 | |
| 9295 // Transfer some number of overflown objects to usual marking | |
| 9296 // stack. Return true if some objects were transferred. | |
| 9297 bool MarkRefsIntoAndScanClosure::take_from_overflow_list() { | |
|
679
cea947c8a988
6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops
ysr
parents:
628
diff
changeset
|
9298 size_t num = MIN2((size_t)(_mark_stack->capacity() - _mark_stack->length())/4, |
| 0 | 9299 (size_t)ParGCDesiredObjsFromOverflowList); |
| 9300 | |
| 9301 bool res = _collector->take_from_overflow_list(num, _mark_stack); | |
| 9302 assert(_collector->overflow_list_is_empty() || res, | |
| 9303 "If list is not empty, we should have taken something"); | |
| 9304 assert(!res || !_mark_stack->isEmpty(), | |
| 9305 "If we took something, it should now be on our stack"); | |
| 9306 return res; | |
| 9307 } | |
| 9308 | |
| 9309 size_t MarkDeadObjectsClosure::do_blk(HeapWord* addr) { | |
| 9310 size_t res = _sp->block_size_no_stall(addr, _collector); | |
| 9311 if (_sp->block_is_obj(addr)) { | |
| 9312 if (_live_bit_map->isMarked(addr)) { | |
| 9313 // It can't have been dead in a previous cycle | |
| 9314 guarantee(!_dead_bit_map->isMarked(addr), "No resurrection!"); | |
| 9315 } else { | |
| 9316 _dead_bit_map->mark(addr); // mark the dead object | |
| 9317 } | |
| 9318 } | |
|
2226
c5a923563727
6912621: iCMS: Error: assert(_markBitMap.isMarked(addr + 1),"Missing Printezis bit?")
ysr
parents:
2177
diff
changeset
|
9319 // Could be 0, if the block size could not be computed without stalling. |
| 0 | 9320 return res; |
| 9321 } | |
|
1703
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9322 |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
9323 TraceCMSMemoryManagerStats::TraceCMSMemoryManagerStats(CMSCollector::CollectorState phase, GCCause::Cause cause): TraceMemoryManagerStats() { |
|
1703
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9324 |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9325 switch (phase) { |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9326 case CMSCollector::InitialMarking: |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9327 initialize(true /* fullGC */ , |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
9328 cause /* cause of the GC */, |
|
1703
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9329 true /* recordGCBeginTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9330 true /* recordPreGCUsage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9331 false /* recordPeakUsage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9332 false /* recordPostGCusage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9333 true /* recordAccumulatedGCTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9334 false /* recordGCEndTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9335 false /* countCollection */ ); |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9336 break; |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9337 |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9338 case CMSCollector::FinalMarking: |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9339 initialize(true /* fullGC */ , |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
9340 cause /* cause of the GC */, |
|
1703
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9341 false /* recordGCBeginTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9342 false /* recordPreGCUsage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9343 false /* recordPeakUsage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9344 false /* recordPostGCusage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9345 true /* recordAccumulatedGCTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9346 false /* recordGCEndTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9347 false /* countCollection */ ); |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9348 break; |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9349 |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9350 case CMSCollector::Sweeping: |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9351 initialize(true /* fullGC */ , |
|
3356
78542e2b5e35
7036199: Adding a notification to the implementation of GarbageCollectorMXBeans
fparain
parents:
3293
diff
changeset
|
9352 cause /* cause of the GC */, |
|
1703
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9353 false /* recordGCBeginTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9354 false /* recordPreGCUsage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9355 true /* recordPeakUsage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9356 true /* recordPostGCusage */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9357 false /* recordAccumulatedGCTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9358 true /* recordGCEndTime */, |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9359 true /* countCollection */ ); |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9360 break; |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9361 |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9362 default: |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9363 ShouldNotReachHere(); |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9364 } |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9365 } |
|
f6f3eef8a521
6581734: CMS Old Gen's collection usage is zero after GC which is incorrect
kevinw
parents:
1579
diff
changeset
|
9366 |