Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/concurrentMark.cpp @ 2125:7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
Summary: Make JvmtiGCMark safe to run non-safepoint and instrument CMS
Reviewed-by: ysr, dcubed
| author | kamg |
|---|---|
| date | Mon, 10 Jan 2011 17:14:53 -0500 |
| parents | b03260081e9b |
| children | 7e37af9d69ef |
| rev | line source |
|---|---|
| 342 | 1 /* |
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2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
| 342 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 342 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "classfile/symbolTable.hpp" | |
| 27 #include "gc_implementation/g1/concurrentMark.hpp" | |
| 28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" | |
| 29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" | |
| 30 #include "gc_implementation/g1/g1CollectorPolicy.hpp" | |
| 31 #include "gc_implementation/g1/g1RemSet.hpp" | |
| 32 #include "gc_implementation/g1/heapRegionRemSet.hpp" | |
| 33 #include "gc_implementation/g1/heapRegionSeq.inline.hpp" | |
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34 #include "gc_implementation/shared/vmGCOperations.hpp" |
| 1972 | 35 #include "memory/genOopClosures.inline.hpp" |
| 36 #include "memory/referencePolicy.hpp" | |
| 37 #include "memory/resourceArea.hpp" | |
| 38 #include "oops/oop.inline.hpp" | |
| 39 #include "runtime/handles.inline.hpp" | |
| 40 #include "runtime/java.hpp" | |
| 342 | 41 |
| 42 // | |
| 43 // CMS Bit Map Wrapper | |
| 44 | |
| 45 CMBitMapRO::CMBitMapRO(ReservedSpace rs, int shifter): | |
| 46 _bm((uintptr_t*)NULL,0), | |
| 47 _shifter(shifter) { | |
| 48 _bmStartWord = (HeapWord*)(rs.base()); | |
| 49 _bmWordSize = rs.size()/HeapWordSize; // rs.size() is in bytes | |
| 50 ReservedSpace brs(ReservedSpace::allocation_align_size_up( | |
| 51 (_bmWordSize >> (_shifter + LogBitsPerByte)) + 1)); | |
| 52 | |
| 53 guarantee(brs.is_reserved(), "couldn't allocate CMS bit map"); | |
| 54 // For now we'll just commit all of the bit map up fromt. | |
| 55 // Later on we'll try to be more parsimonious with swap. | |
| 56 guarantee(_virtual_space.initialize(brs, brs.size()), | |
| 57 "couldn't reseve backing store for CMS bit map"); | |
| 58 assert(_virtual_space.committed_size() == brs.size(), | |
| 59 "didn't reserve backing store for all of CMS bit map?"); | |
| 60 _bm.set_map((uintptr_t*)_virtual_space.low()); | |
| 61 assert(_virtual_space.committed_size() << (_shifter + LogBitsPerByte) >= | |
| 62 _bmWordSize, "inconsistency in bit map sizing"); | |
| 63 _bm.set_size(_bmWordSize >> _shifter); | |
| 64 } | |
| 65 | |
| 66 HeapWord* CMBitMapRO::getNextMarkedWordAddress(HeapWord* addr, | |
| 67 HeapWord* limit) const { | |
| 68 // First we must round addr *up* to a possible object boundary. | |
| 69 addr = (HeapWord*)align_size_up((intptr_t)addr, | |
| 70 HeapWordSize << _shifter); | |
| 71 size_t addrOffset = heapWordToOffset(addr); | |
| 72 if (limit == NULL) limit = _bmStartWord + _bmWordSize; | |
| 73 size_t limitOffset = heapWordToOffset(limit); | |
| 74 size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset); | |
| 75 HeapWord* nextAddr = offsetToHeapWord(nextOffset); | |
| 76 assert(nextAddr >= addr, "get_next_one postcondition"); | |
| 77 assert(nextAddr == limit || isMarked(nextAddr), | |
| 78 "get_next_one postcondition"); | |
| 79 return nextAddr; | |
| 80 } | |
| 81 | |
| 82 HeapWord* CMBitMapRO::getNextUnmarkedWordAddress(HeapWord* addr, | |
| 83 HeapWord* limit) const { | |
| 84 size_t addrOffset = heapWordToOffset(addr); | |
| 85 if (limit == NULL) limit = _bmStartWord + _bmWordSize; | |
| 86 size_t limitOffset = heapWordToOffset(limit); | |
| 87 size_t nextOffset = _bm.get_next_zero_offset(addrOffset, limitOffset); | |
| 88 HeapWord* nextAddr = offsetToHeapWord(nextOffset); | |
| 89 assert(nextAddr >= addr, "get_next_one postcondition"); | |
| 90 assert(nextAddr == limit || !isMarked(nextAddr), | |
| 91 "get_next_one postcondition"); | |
| 92 return nextAddr; | |
| 93 } | |
| 94 | |
| 95 int CMBitMapRO::heapWordDiffToOffsetDiff(size_t diff) const { | |
| 96 assert((diff & ((1 << _shifter) - 1)) == 0, "argument check"); | |
| 97 return (int) (diff >> _shifter); | |
| 98 } | |
| 99 | |
| 100 bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { | |
| 101 HeapWord* left = MAX2(_bmStartWord, mr.start()); | |
| 102 HeapWord* right = MIN2(_bmStartWord + _bmWordSize, mr.end()); | |
| 103 if (right > left) { | |
| 104 // Right-open interval [leftOffset, rightOffset). | |
| 105 return _bm.iterate(cl, heapWordToOffset(left), heapWordToOffset(right)); | |
| 106 } else { | |
| 107 return true; | |
| 108 } | |
| 109 } | |
| 110 | |
| 111 void CMBitMapRO::mostly_disjoint_range_union(BitMap* from_bitmap, | |
| 112 size_t from_start_index, | |
| 113 HeapWord* to_start_word, | |
| 114 size_t word_num) { | |
| 115 _bm.mostly_disjoint_range_union(from_bitmap, | |
| 116 from_start_index, | |
| 117 heapWordToOffset(to_start_word), | |
| 118 word_num); | |
| 119 } | |
| 120 | |
| 121 #ifndef PRODUCT | |
| 122 bool CMBitMapRO::covers(ReservedSpace rs) const { | |
| 123 // assert(_bm.map() == _virtual_space.low(), "map inconsistency"); | |
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124 assert(((size_t)_bm.size() * (size_t)(1 << _shifter)) == _bmWordSize, |
| 342 | 125 "size inconsistency"); |
| 126 return _bmStartWord == (HeapWord*)(rs.base()) && | |
| 127 _bmWordSize == rs.size()>>LogHeapWordSize; | |
| 128 } | |
| 129 #endif | |
| 130 | |
| 131 void CMBitMap::clearAll() { | |
| 132 _bm.clear(); | |
| 133 return; | |
| 134 } | |
| 135 | |
| 136 void CMBitMap::markRange(MemRegion mr) { | |
| 137 mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 138 assert(!mr.is_empty(), "unexpected empty region"); | |
| 139 assert((offsetToHeapWord(heapWordToOffset(mr.end())) == | |
| 140 ((HeapWord *) mr.end())), | |
| 141 "markRange memory region end is not card aligned"); | |
| 142 // convert address range into offset range | |
| 143 _bm.at_put_range(heapWordToOffset(mr.start()), | |
| 144 heapWordToOffset(mr.end()), true); | |
| 145 } | |
| 146 | |
| 147 void CMBitMap::clearRange(MemRegion mr) { | |
| 148 mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 149 assert(!mr.is_empty(), "unexpected empty region"); | |
| 150 // convert address range into offset range | |
| 151 _bm.at_put_range(heapWordToOffset(mr.start()), | |
| 152 heapWordToOffset(mr.end()), false); | |
| 153 } | |
| 154 | |
| 155 MemRegion CMBitMap::getAndClearMarkedRegion(HeapWord* addr, | |
| 156 HeapWord* end_addr) { | |
| 157 HeapWord* start = getNextMarkedWordAddress(addr); | |
| 158 start = MIN2(start, end_addr); | |
| 159 HeapWord* end = getNextUnmarkedWordAddress(start); | |
| 160 end = MIN2(end, end_addr); | |
| 161 assert(start <= end, "Consistency check"); | |
| 162 MemRegion mr(start, end); | |
| 163 if (!mr.is_empty()) { | |
| 164 clearRange(mr); | |
| 165 } | |
| 166 return mr; | |
| 167 } | |
| 168 | |
| 169 CMMarkStack::CMMarkStack(ConcurrentMark* cm) : | |
| 170 _base(NULL), _cm(cm) | |
| 171 #ifdef ASSERT | |
| 172 , _drain_in_progress(false) | |
| 173 , _drain_in_progress_yields(false) | |
| 174 #endif | |
| 175 {} | |
| 176 | |
| 177 void CMMarkStack::allocate(size_t size) { | |
| 178 _base = NEW_C_HEAP_ARRAY(oop, size); | |
| 179 if (_base == NULL) | |
| 180 vm_exit_during_initialization("Failed to allocate " | |
| 181 "CM region mark stack"); | |
| 182 _index = 0; | |
| 183 // QQQQ cast ... | |
| 184 _capacity = (jint) size; | |
| 185 _oops_do_bound = -1; | |
| 186 NOT_PRODUCT(_max_depth = 0); | |
| 187 } | |
| 188 | |
| 189 CMMarkStack::~CMMarkStack() { | |
| 190 if (_base != NULL) FREE_C_HEAP_ARRAY(oop, _base); | |
| 191 } | |
| 192 | |
| 193 void CMMarkStack::par_push(oop ptr) { | |
| 194 while (true) { | |
| 195 if (isFull()) { | |
| 196 _overflow = true; | |
| 197 return; | |
| 198 } | |
| 199 // Otherwise... | |
| 200 jint index = _index; | |
| 201 jint next_index = index+1; | |
| 202 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 203 if (res == index) { | |
| 204 _base[index] = ptr; | |
| 205 // Note that we don't maintain this atomically. We could, but it | |
| 206 // doesn't seem necessary. | |
| 207 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index)); | |
| 208 return; | |
| 209 } | |
| 210 // Otherwise, we need to try again. | |
| 211 } | |
| 212 } | |
| 213 | |
| 214 void CMMarkStack::par_adjoin_arr(oop* ptr_arr, int n) { | |
| 215 while (true) { | |
| 216 if (isFull()) { | |
| 217 _overflow = true; | |
| 218 return; | |
| 219 } | |
| 220 // Otherwise... | |
| 221 jint index = _index; | |
| 222 jint next_index = index + n; | |
| 223 if (next_index > _capacity) { | |
| 224 _overflow = true; | |
| 225 return; | |
| 226 } | |
| 227 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 228 if (res == index) { | |
| 229 for (int i = 0; i < n; i++) { | |
| 230 int ind = index + i; | |
| 231 assert(ind < _capacity, "By overflow test above."); | |
| 232 _base[ind] = ptr_arr[i]; | |
| 233 } | |
| 234 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index)); | |
| 235 return; | |
| 236 } | |
| 237 // Otherwise, we need to try again. | |
| 238 } | |
| 239 } | |
| 240 | |
| 241 | |
| 242 void CMMarkStack::par_push_arr(oop* ptr_arr, int n) { | |
| 243 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 244 jint start = _index; | |
| 245 jint next_index = start + n; | |
| 246 if (next_index > _capacity) { | |
| 247 _overflow = true; | |
| 248 return; | |
| 249 } | |
| 250 // Otherwise. | |
| 251 _index = next_index; | |
| 252 for (int i = 0; i < n; i++) { | |
| 253 int ind = start + i; | |
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254 assert(ind < _capacity, "By overflow test above."); |
| 342 | 255 _base[ind] = ptr_arr[i]; |
| 256 } | |
| 257 } | |
| 258 | |
| 259 | |
| 260 bool CMMarkStack::par_pop_arr(oop* ptr_arr, int max, int* n) { | |
| 261 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 262 jint index = _index; | |
| 263 if (index == 0) { | |
| 264 *n = 0; | |
| 265 return false; | |
| 266 } else { | |
| 267 int k = MIN2(max, index); | |
| 268 jint new_ind = index - k; | |
| 269 for (int j = 0; j < k; j++) { | |
| 270 ptr_arr[j] = _base[new_ind + j]; | |
| 271 } | |
| 272 _index = new_ind; | |
| 273 *n = k; | |
| 274 return true; | |
| 275 } | |
| 276 } | |
| 277 | |
| 278 | |
| 279 CMRegionStack::CMRegionStack() : _base(NULL) {} | |
| 280 | |
| 281 void CMRegionStack::allocate(size_t size) { | |
| 282 _base = NEW_C_HEAP_ARRAY(MemRegion, size); | |
| 283 if (_base == NULL) | |
| 284 vm_exit_during_initialization("Failed to allocate " | |
| 285 "CM region mark stack"); | |
| 286 _index = 0; | |
| 287 // QQQQ cast ... | |
| 288 _capacity = (jint) size; | |
| 289 } | |
| 290 | |
| 291 CMRegionStack::~CMRegionStack() { | |
| 292 if (_base != NULL) FREE_C_HEAP_ARRAY(oop, _base); | |
| 293 } | |
| 294 | |
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295 void CMRegionStack::push_lock_free(MemRegion mr) { |
| 342 | 296 assert(mr.word_size() > 0, "Precondition"); |
| 297 while (true) { | |
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298 jint index = _index; |
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299 |
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300 if (index >= _capacity) { |
| 342 | 301 _overflow = true; |
| 302 return; | |
| 303 } | |
| 304 // Otherwise... | |
| 305 jint next_index = index+1; | |
| 306 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 307 if (res == index) { | |
| 308 _base[index] = mr; | |
| 309 return; | |
| 310 } | |
| 311 // Otherwise, we need to try again. | |
| 312 } | |
| 313 } | |
| 314 | |
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315 // Lock-free pop of the region stack. Called during the concurrent |
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316 // marking / remark phases. Should only be called in tandem with |
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317 // other lock-free pops. |
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318 MemRegion CMRegionStack::pop_lock_free() { |
| 342 | 319 while (true) { |
| 320 jint index = _index; | |
| 321 | |
| 322 if (index == 0) { | |
| 323 return MemRegion(); | |
| 324 } | |
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325 // Otherwise... |
| 342 | 326 jint next_index = index-1; |
| 327 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 328 if (res == index) { | |
| 329 MemRegion mr = _base[next_index]; | |
| 330 if (mr.start() != NULL) { | |
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331 assert(mr.end() != NULL, "invariant"); |
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332 assert(mr.word_size() > 0, "invariant"); |
| 342 | 333 return mr; |
| 334 } else { | |
| 335 // that entry was invalidated... let's skip it | |
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336 assert(mr.end() == NULL, "invariant"); |
| 342 | 337 } |
| 338 } | |
| 339 // Otherwise, we need to try again. | |
| 340 } | |
| 341 } | |
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342 |
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343 #if 0 |
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344 // The routines that manipulate the region stack with a lock are |
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345 // not currently used. They should be retained, however, as a |
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346 // diagnostic aid. |
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347 |
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348 void CMRegionStack::push_with_lock(MemRegion mr) { |
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349 assert(mr.word_size() > 0, "Precondition"); |
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350 MutexLockerEx x(CMRegionStack_lock, Mutex::_no_safepoint_check_flag); |
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351 |
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352 if (isFull()) { |
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353 _overflow = true; |
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354 return; |
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355 } |
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356 |
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357 _base[_index] = mr; |
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358 _index += 1; |
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359 } |
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360 |
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361 MemRegion CMRegionStack::pop_with_lock() { |
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362 MutexLockerEx x(CMRegionStack_lock, Mutex::_no_safepoint_check_flag); |
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363 |
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364 while (true) { |
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365 if (_index == 0) { |
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366 return MemRegion(); |
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367 } |
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368 _index -= 1; |
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369 |
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370 MemRegion mr = _base[_index]; |
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371 if (mr.start() != NULL) { |
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372 assert(mr.end() != NULL, "invariant"); |
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373 assert(mr.word_size() > 0, "invariant"); |
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374 return mr; |
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375 } else { |
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376 // that entry was invalidated... let's skip it |
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377 assert(mr.end() == NULL, "invariant"); |
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378 } |
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379 } |
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380 } |
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381 #endif |
| 342 | 382 |
| 383 bool CMRegionStack::invalidate_entries_into_cset() { | |
| 384 bool result = false; | |
| 385 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 386 for (int i = 0; i < _oops_do_bound; ++i) { | |
| 387 MemRegion mr = _base[i]; | |
| 388 if (mr.start() != NULL) { | |
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389 assert(mr.end() != NULL, "invariant"); |
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390 assert(mr.word_size() > 0, "invariant"); |
| 342 | 391 HeapRegion* hr = g1h->heap_region_containing(mr.start()); |
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392 assert(hr != NULL, "invariant"); |
| 342 | 393 if (hr->in_collection_set()) { |
| 394 // The region points into the collection set | |
| 395 _base[i] = MemRegion(); | |
| 396 result = true; | |
| 397 } | |
| 398 } else { | |
| 399 // that entry was invalidated... let's skip it | |
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400 assert(mr.end() == NULL, "invariant"); |
| 342 | 401 } |
| 402 } | |
| 403 return result; | |
| 404 } | |
| 405 | |
| 406 template<class OopClosureClass> | |
| 407 bool CMMarkStack::drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after) { | |
| 408 assert(!_drain_in_progress || !_drain_in_progress_yields || yield_after | |
| 409 || SafepointSynchronize::is_at_safepoint(), | |
| 410 "Drain recursion must be yield-safe."); | |
| 411 bool res = true; | |
| 412 debug_only(_drain_in_progress = true); | |
| 413 debug_only(_drain_in_progress_yields = yield_after); | |
| 414 while (!isEmpty()) { | |
| 415 oop newOop = pop(); | |
| 416 assert(G1CollectedHeap::heap()->is_in_reserved(newOop), "Bad pop"); | |
| 417 assert(newOop->is_oop(), "Expected an oop"); | |
| 418 assert(bm == NULL || bm->isMarked((HeapWord*)newOop), | |
| 419 "only grey objects on this stack"); | |
| 420 // iterate over the oops in this oop, marking and pushing | |
| 421 // the ones in CMS generation. | |
| 422 newOop->oop_iterate(cl); | |
| 423 if (yield_after && _cm->do_yield_check()) { | |
| 424 res = false; break; | |
| 425 } | |
| 426 } | |
| 427 debug_only(_drain_in_progress = false); | |
| 428 return res; | |
| 429 } | |
| 430 | |
| 431 void CMMarkStack::oops_do(OopClosure* f) { | |
| 432 if (_index == 0) return; | |
| 433 assert(_oops_do_bound != -1 && _oops_do_bound <= _index, | |
| 434 "Bound must be set."); | |
| 435 for (int i = 0; i < _oops_do_bound; i++) { | |
| 436 f->do_oop(&_base[i]); | |
| 437 } | |
| 438 _oops_do_bound = -1; | |
| 439 } | |
| 440 | |
| 441 bool ConcurrentMark::not_yet_marked(oop obj) const { | |
| 442 return (_g1h->is_obj_ill(obj) | |
| 443 || (_g1h->is_in_permanent(obj) | |
| 444 && !nextMarkBitMap()->isMarked((HeapWord*)obj))); | |
| 445 } | |
| 446 | |
| 447 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away | |
| 448 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list | |
| 449 #endif // _MSC_VER | |
| 450 | |
| 451 ConcurrentMark::ConcurrentMark(ReservedSpace rs, | |
| 452 int max_regions) : | |
| 453 _markBitMap1(rs, MinObjAlignment - 1), | |
| 454 _markBitMap2(rs, MinObjAlignment - 1), | |
| 455 | |
| 456 _parallel_marking_threads(0), | |
| 457 _sleep_factor(0.0), | |
| 458 _marking_task_overhead(1.0), | |
| 459 _cleanup_sleep_factor(0.0), | |
| 460 _cleanup_task_overhead(1.0), | |
| 461 _region_bm(max_regions, false /* in_resource_area*/), | |
| 462 _card_bm((rs.size() + CardTableModRefBS::card_size - 1) >> | |
| 463 CardTableModRefBS::card_shift, | |
| 464 false /* in_resource_area*/), | |
| 465 _prevMarkBitMap(&_markBitMap1), | |
| 466 _nextMarkBitMap(&_markBitMap2), | |
| 467 _at_least_one_mark_complete(false), | |
| 468 | |
| 469 _markStack(this), | |
| 470 _regionStack(), | |
| 471 // _finger set in set_non_marking_state | |
| 472 | |
| 473 _max_task_num(MAX2(ParallelGCThreads, (size_t)1)), | |
| 474 // _active_tasks set in set_non_marking_state | |
| 475 // _tasks set inside the constructor | |
| 476 _task_queues(new CMTaskQueueSet((int) _max_task_num)), | |
| 477 _terminator(ParallelTaskTerminator((int) _max_task_num, _task_queues)), | |
| 478 | |
| 479 _has_overflown(false), | |
| 480 _concurrent(false), | |
|
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481 _has_aborted(false), |
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482 _restart_for_overflow(false), |
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483 _concurrent_marking_in_progress(false), |
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484 _should_gray_objects(false), |
| 342 | 485 |
| 486 // _verbose_level set below | |
| 487 | |
| 488 _init_times(), | |
| 489 _remark_times(), _remark_mark_times(), _remark_weak_ref_times(), | |
| 490 _cleanup_times(), | |
| 491 _total_counting_time(0.0), | |
| 492 _total_rs_scrub_time(0.0), | |
| 493 | |
| 936 | 494 _parallel_workers(NULL) |
| 342 | 495 { |
| 496 CMVerboseLevel verbose_level = | |
| 497 (CMVerboseLevel) G1MarkingVerboseLevel; | |
| 498 if (verbose_level < no_verbose) | |
| 499 verbose_level = no_verbose; | |
| 500 if (verbose_level > high_verbose) | |
| 501 verbose_level = high_verbose; | |
| 502 _verbose_level = verbose_level; | |
| 503 | |
| 504 if (verbose_low()) | |
| 505 gclog_or_tty->print_cr("[global] init, heap start = "PTR_FORMAT", " | |
| 506 "heap end = "PTR_FORMAT, _heap_start, _heap_end); | |
| 507 | |
| 1284 | 508 _markStack.allocate(MarkStackSize); |
| 751 | 509 _regionStack.allocate(G1MarkRegionStackSize); |
| 342 | 510 |
| 511 // Create & start a ConcurrentMark thread. | |
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512 _cmThread = new ConcurrentMarkThread(this); |
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513 assert(cmThread() != NULL, "CM Thread should have been created"); |
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514 assert(cmThread()->cm() != NULL, "CM Thread should refer to this cm"); |
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515 |
| 342 | 516 _g1h = G1CollectedHeap::heap(); |
| 517 assert(CGC_lock != NULL, "Where's the CGC_lock?"); | |
| 518 assert(_markBitMap1.covers(rs), "_markBitMap1 inconsistency"); | |
| 519 assert(_markBitMap2.covers(rs), "_markBitMap2 inconsistency"); | |
| 520 | |
| 521 SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set(); | |
| 1282 | 522 satb_qs.set_buffer_size(G1SATBBufferSize); |
| 342 | 523 |
| 524 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 525 _par_cleanup_thread_state = NEW_C_HEAP_ARRAY(ParCleanupThreadState*, size); | |
| 526 for (int i = 0 ; i < size; i++) { | |
| 527 _par_cleanup_thread_state[i] = new ParCleanupThreadState; | |
| 528 } | |
| 529 | |
| 530 _tasks = NEW_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 531 _accum_task_vtime = NEW_C_HEAP_ARRAY(double, _max_task_num); | |
| 532 | |
| 533 // so that the assertion in MarkingTaskQueue::task_queue doesn't fail | |
| 534 _active_tasks = _max_task_num; | |
| 535 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 536 CMTaskQueue* task_queue = new CMTaskQueue(); | |
| 537 task_queue->initialize(); | |
| 538 _task_queues->register_queue(i, task_queue); | |
| 539 | |
| 540 _tasks[i] = new CMTask(i, this, task_queue, _task_queues); | |
| 541 _accum_task_vtime[i] = 0.0; | |
| 542 } | |
| 543 | |
| 1284 | 544 if (ConcGCThreads > ParallelGCThreads) { |
| 545 vm_exit_during_initialization("Can't have more ConcGCThreads " | |
| 342 | 546 "than ParallelGCThreads."); |
| 547 } | |
| 548 if (ParallelGCThreads == 0) { | |
| 549 // if we are not running with any parallel GC threads we will not | |
| 550 // spawn any marking threads either | |
| 551 _parallel_marking_threads = 0; | |
| 552 _sleep_factor = 0.0; | |
| 553 _marking_task_overhead = 1.0; | |
| 554 } else { | |
| 1284 | 555 if (ConcGCThreads > 0) { |
| 556 // notice that ConcGCThreads overwrites G1MarkingOverheadPercent | |
| 342 | 557 // if both are set |
| 558 | |
| 1284 | 559 _parallel_marking_threads = ConcGCThreads; |
| 342 | 560 _sleep_factor = 0.0; |
| 561 _marking_task_overhead = 1.0; | |
| 751 | 562 } else if (G1MarkingOverheadPercent > 0) { |
| 342 | 563 // we will calculate the number of parallel marking threads |
| 564 // based on a target overhead with respect to the soft real-time | |
| 565 // goal | |
| 566 | |
| 751 | 567 double marking_overhead = (double) G1MarkingOverheadPercent / 100.0; |
| 342 | 568 double overall_cm_overhead = |
| 751 | 569 (double) MaxGCPauseMillis * marking_overhead / |
| 570 (double) GCPauseIntervalMillis; | |
| 342 | 571 double cpu_ratio = 1.0 / (double) os::processor_count(); |
| 572 double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio); | |
| 573 double marking_task_overhead = | |
| 574 overall_cm_overhead / marking_thread_num * | |
| 575 (double) os::processor_count(); | |
| 576 double sleep_factor = | |
| 577 (1.0 - marking_task_overhead) / marking_task_overhead; | |
| 578 | |
| 579 _parallel_marking_threads = (size_t) marking_thread_num; | |
| 580 _sleep_factor = sleep_factor; | |
| 581 _marking_task_overhead = marking_task_overhead; | |
| 582 } else { | |
| 583 _parallel_marking_threads = MAX2((ParallelGCThreads + 2) / 4, (size_t)1); | |
| 584 _sleep_factor = 0.0; | |
| 585 _marking_task_overhead = 1.0; | |
| 586 } | |
| 587 | |
| 588 if (parallel_marking_threads() > 1) | |
| 589 _cleanup_task_overhead = 1.0; | |
| 590 else | |
| 591 _cleanup_task_overhead = marking_task_overhead(); | |
| 592 _cleanup_sleep_factor = | |
| 593 (1.0 - cleanup_task_overhead()) / cleanup_task_overhead(); | |
| 594 | |
| 595 #if 0 | |
| 596 gclog_or_tty->print_cr("Marking Threads %d", parallel_marking_threads()); | |
| 597 gclog_or_tty->print_cr("CM Marking Task Overhead %1.4lf", marking_task_overhead()); | |
| 598 gclog_or_tty->print_cr("CM Sleep Factor %1.4lf", sleep_factor()); | |
| 599 gclog_or_tty->print_cr("CL Marking Task Overhead %1.4lf", cleanup_task_overhead()); | |
| 600 gclog_or_tty->print_cr("CL Sleep Factor %1.4lf", cleanup_sleep_factor()); | |
| 601 #endif | |
| 602 | |
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603 guarantee(parallel_marking_threads() > 0, "peace of mind"); |
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604 _parallel_workers = new FlexibleWorkGang("G1 Parallel Marking Threads", |
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605 (int) _parallel_marking_threads, false, true); |
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606 if (_parallel_workers == NULL) { |
| 342 | 607 vm_exit_during_initialization("Failed necessary allocation."); |
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608 } else { |
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609 _parallel_workers->initialize_workers(); |
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610 } |
| 342 | 611 } |
| 612 | |
| 613 // so that the call below can read a sensible value | |
| 614 _heap_start = (HeapWord*) rs.base(); | |
| 615 set_non_marking_state(); | |
| 616 } | |
| 617 | |
| 618 void ConcurrentMark::update_g1_committed(bool force) { | |
| 619 // If concurrent marking is not in progress, then we do not need to | |
| 620 // update _heap_end. This has a subtle and important | |
| 621 // side-effect. Imagine that two evacuation pauses happen between | |
| 622 // marking completion and remark. The first one can grow the | |
| 623 // heap (hence now the finger is below the heap end). Then, the | |
| 624 // second one could unnecessarily push regions on the region | |
| 625 // stack. This causes the invariant that the region stack is empty | |
| 626 // at the beginning of remark to be false. By ensuring that we do | |
| 627 // not observe heap expansions after marking is complete, then we do | |
| 628 // not have this problem. | |
| 629 if (!concurrent_marking_in_progress() && !force) | |
| 630 return; | |
| 631 | |
| 632 MemRegion committed = _g1h->g1_committed(); | |
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633 assert(committed.start() == _heap_start, "start shouldn't change"); |
| 342 | 634 HeapWord* new_end = committed.end(); |
| 635 if (new_end > _heap_end) { | |
| 636 // The heap has been expanded. | |
| 637 | |
| 638 _heap_end = new_end; | |
| 639 } | |
| 640 // Notice that the heap can also shrink. However, this only happens | |
| 641 // during a Full GC (at least currently) and the entire marking | |
| 642 // phase will bail out and the task will not be restarted. So, let's | |
| 643 // do nothing. | |
| 644 } | |
| 645 | |
| 646 void ConcurrentMark::reset() { | |
| 647 // Starting values for these two. This should be called in a STW | |
| 648 // phase. CM will be notified of any future g1_committed expansions | |
| 649 // will be at the end of evacuation pauses, when tasks are | |
| 650 // inactive. | |
| 651 MemRegion committed = _g1h->g1_committed(); | |
| 652 _heap_start = committed.start(); | |
| 653 _heap_end = committed.end(); | |
| 654 | |
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655 // Separated the asserts so that we know which one fires. |
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656 assert(_heap_start != NULL, "heap bounds should look ok"); |
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657 assert(_heap_end != NULL, "heap bounds should look ok"); |
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658 assert(_heap_start < _heap_end, "heap bounds should look ok"); |
| 342 | 659 |
| 660 // reset all the marking data structures and any necessary flags | |
| 661 clear_marking_state(); | |
| 662 | |
| 663 if (verbose_low()) | |
| 664 gclog_or_tty->print_cr("[global] resetting"); | |
| 665 | |
| 666 // We do reset all of them, since different phases will use | |
| 667 // different number of active threads. So, it's easiest to have all | |
| 668 // of them ready. | |
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669 for (int i = 0; i < (int) _max_task_num; ++i) { |
| 342 | 670 _tasks[i]->reset(_nextMarkBitMap); |
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671 } |
| 342 | 672 |
| 673 // we need this to make sure that the flag is on during the evac | |
| 674 // pause with initial mark piggy-backed | |
| 675 set_concurrent_marking_in_progress(); | |
| 676 } | |
| 677 | |
| 678 void ConcurrentMark::set_phase(size_t active_tasks, bool concurrent) { | |
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679 assert(active_tasks <= _max_task_num, "we should not have more"); |
| 342 | 680 |
| 681 _active_tasks = active_tasks; | |
| 682 // Need to update the three data structures below according to the | |
| 683 // number of active threads for this phase. | |
| 684 _terminator = ParallelTaskTerminator((int) active_tasks, _task_queues); | |
| 685 _first_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 686 _second_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 687 | |
| 688 _concurrent = concurrent; | |
| 689 // We propagate this to all tasks, not just the active ones. | |
| 690 for (int i = 0; i < (int) _max_task_num; ++i) | |
| 691 _tasks[i]->set_concurrent(concurrent); | |
| 692 | |
| 693 if (concurrent) { | |
| 694 set_concurrent_marking_in_progress(); | |
| 695 } else { | |
| 696 // We currently assume that the concurrent flag has been set to | |
| 697 // false before we start remark. At this point we should also be | |
| 698 // in a STW phase. | |
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699 assert(!concurrent_marking_in_progress(), "invariant"); |
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700 assert(_finger == _heap_end, "only way to get here"); |
| 342 | 701 update_g1_committed(true); |
| 702 } | |
| 703 } | |
| 704 | |
| 705 void ConcurrentMark::set_non_marking_state() { | |
| 706 // We set the global marking state to some default values when we're | |
| 707 // not doing marking. | |
| 708 clear_marking_state(); | |
| 709 _active_tasks = 0; | |
| 710 clear_concurrent_marking_in_progress(); | |
| 711 } | |
| 712 | |
| 713 ConcurrentMark::~ConcurrentMark() { | |
| 714 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 715 for (int i = 0; i < size; i++) delete _par_cleanup_thread_state[i]; | |
| 716 FREE_C_HEAP_ARRAY(ParCleanupThreadState*, | |
| 717 _par_cleanup_thread_state); | |
| 718 | |
| 719 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 720 delete _task_queues->queue(i); | |
| 721 delete _tasks[i]; | |
| 722 } | |
| 723 delete _task_queues; | |
| 724 FREE_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 725 } | |
| 726 | |
| 727 // This closure is used to mark refs into the g1 generation | |
| 728 // from external roots in the CMS bit map. | |
| 729 // Called at the first checkpoint. | |
| 730 // | |
| 731 | |
| 732 void ConcurrentMark::clearNextBitmap() { | |
|
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733 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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734 G1CollectorPolicy* g1p = g1h->g1_policy(); |
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735 |
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736 // Make sure that the concurrent mark thread looks to still be in |
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737 // the current cycle. |
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738 guarantee(cmThread()->during_cycle(), "invariant"); |
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739 |
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740 // We are finishing up the current cycle by clearing the next |
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741 // marking bitmap and getting it ready for the next cycle. During |
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742 // this time no other cycle can start. So, let's make sure that this |
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743 // is the case. |
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744 guarantee(!g1h->mark_in_progress(), "invariant"); |
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745 |
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746 // clear the mark bitmap (no grey objects to start with). |
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747 // We need to do this in chunks and offer to yield in between |
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748 // each chunk. |
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749 HeapWord* start = _nextMarkBitMap->startWord(); |
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750 HeapWord* end = _nextMarkBitMap->endWord(); |
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751 HeapWord* cur = start; |
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752 size_t chunkSize = M; |
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753 while (cur < end) { |
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754 HeapWord* next = cur + chunkSize; |
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755 if (next > end) |
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756 next = end; |
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757 MemRegion mr(cur,next); |
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758 _nextMarkBitMap->clearRange(mr); |
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759 cur = next; |
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760 do_yield_check(); |
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761 |
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762 // Repeat the asserts from above. We'll do them as asserts here to |
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763 // minimize their overhead on the product. However, we'll have |
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764 // them as guarantees at the beginning / end of the bitmap |
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765 // clearing to get some checking in the product. |
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766 assert(cmThread()->during_cycle(), "invariant"); |
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767 assert(!g1h->mark_in_progress(), "invariant"); |
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768 } |
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769 |
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770 // Repeat the asserts from above. |
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771 guarantee(cmThread()->during_cycle(), "invariant"); |
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772 guarantee(!g1h->mark_in_progress(), "invariant"); |
| 342 | 773 } |
| 774 | |
| 775 class NoteStartOfMarkHRClosure: public HeapRegionClosure { | |
| 776 public: | |
| 777 bool doHeapRegion(HeapRegion* r) { | |
| 778 if (!r->continuesHumongous()) { | |
| 779 r->note_start_of_marking(true); | |
| 780 } | |
| 781 return false; | |
| 782 } | |
| 783 }; | |
| 784 | |
| 785 void ConcurrentMark::checkpointRootsInitialPre() { | |
| 786 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 787 G1CollectorPolicy* g1p = g1h->g1_policy(); | |
| 788 | |
| 789 _has_aborted = false; | |
| 790 | |
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791 #ifndef PRODUCT |
| 1044 | 792 if (G1PrintReachableAtInitialMark) { |
| 1388 | 793 print_reachable("at-cycle-start", |
| 794 true /* use_prev_marking */, true /* all */); | |
| 1044 | 795 } |
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796 #endif |
| 342 | 797 |
| 798 // Initialise marking structures. This has to be done in a STW phase. | |
| 799 reset(); | |
| 800 } | |
| 801 | |
| 802 class CMMarkRootsClosure: public OopsInGenClosure { | |
| 803 private: | |
| 804 ConcurrentMark* _cm; | |
| 805 G1CollectedHeap* _g1h; | |
| 806 bool _do_barrier; | |
| 807 | |
| 808 public: | |
| 809 CMMarkRootsClosure(ConcurrentMark* cm, | |
| 810 G1CollectedHeap* g1h, | |
| 811 bool do_barrier) : _cm(cm), _g1h(g1h), | |
| 812 _do_barrier(do_barrier) { } | |
| 813 | |
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814 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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815 virtual void do_oop( oop* p) { do_oop_work(p); } |
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816 |
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817 template <class T> void do_oop_work(T* p) { |
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818 T heap_oop = oopDesc::load_heap_oop(p); |
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819 if (!oopDesc::is_null(heap_oop)) { |
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820 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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821 assert(obj->is_oop() || obj->mark() == NULL, |
| 342 | 822 "expected an oop, possibly with mark word displaced"); |
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823 HeapWord* addr = (HeapWord*)obj; |
| 342 | 824 if (_g1h->is_in_g1_reserved(addr)) { |
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825 _cm->grayRoot(obj); |
| 342 | 826 } |
| 827 } | |
| 828 if (_do_barrier) { | |
| 829 assert(!_g1h->is_in_g1_reserved(p), | |
| 830 "Should be called on external roots"); | |
| 831 do_barrier(p); | |
| 832 } | |
| 833 } | |
| 834 }; | |
| 835 | |
| 836 void ConcurrentMark::checkpointRootsInitialPost() { | |
| 837 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 838 | |
| 839 // For each region note start of marking. | |
| 840 NoteStartOfMarkHRClosure startcl; | |
| 841 g1h->heap_region_iterate(&startcl); | |
| 842 | |
| 843 // Start weak-reference discovery. | |
| 844 ReferenceProcessor* rp = g1h->ref_processor(); | |
| 845 rp->verify_no_references_recorded(); | |
| 846 rp->enable_discovery(); // enable ("weak") refs discovery | |
|
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847 rp->setup_policy(false); // snapshot the soft ref policy to be used in this cycle |
| 342 | 848 |
| 849 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
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850 // This is the start of the marking cycle, we're expected all |
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851 // threads to have SATB queues with active set to false. |
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852 satb_mq_set.set_active_all_threads(true, /* new active value */ |
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853 false /* expected_active */); |
| 342 | 854 |
| 855 // update_g1_committed() will be called at the end of an evac pause | |
| 856 // when marking is on. So, it's also called at the end of the | |
| 857 // initial-mark pause to update the heap end, if the heap expands | |
| 858 // during it. No need to call it here. | |
| 859 } | |
| 860 | |
| 861 // Checkpoint the roots into this generation from outside | |
| 862 // this generation. [Note this initial checkpoint need only | |
| 863 // be approximate -- we'll do a catch up phase subsequently.] | |
| 864 void ConcurrentMark::checkpointRootsInitial() { | |
| 865 assert(SafepointSynchronize::is_at_safepoint(), "world should be stopped"); | |
| 866 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 867 | |
| 868 double start = os::elapsedTime(); | |
| 869 | |
| 870 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); | |
| 871 g1p->record_concurrent_mark_init_start(); | |
| 872 checkpointRootsInitialPre(); | |
| 873 | |
| 874 // YSR: when concurrent precleaning is in place, we'll | |
| 875 // need to clear the cached card table here | |
| 876 | |
| 877 ResourceMark rm; | |
| 878 HandleMark hm; | |
| 879 | |
| 880 g1h->ensure_parsability(false); | |
| 881 g1h->perm_gen()->save_marks(); | |
| 882 | |
| 883 CMMarkRootsClosure notOlder(this, g1h, false); | |
| 884 CMMarkRootsClosure older(this, g1h, true); | |
| 885 | |
| 886 g1h->set_marking_started(); | |
| 887 g1h->rem_set()->prepare_for_younger_refs_iterate(false); | |
| 888 | |
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889 g1h->process_strong_roots(true, // activate StrongRootsScope |
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890 false, // fake perm gen collection |
| 342 | 891 SharedHeap::SO_AllClasses, |
| 892 ¬Older, // Regular roots | |
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893 NULL, // do not visit active blobs |
| 342 | 894 &older // Perm Gen Roots |
| 895 ); | |
| 896 checkpointRootsInitialPost(); | |
| 897 | |
| 898 // Statistics. | |
| 899 double end = os::elapsedTime(); | |
| 900 _init_times.add((end - start) * 1000.0); | |
| 901 | |
| 902 g1p->record_concurrent_mark_init_end(); | |
| 903 } | |
| 904 | |
| 905 /* | |
| 906 Notice that in the next two methods, we actually leave the STS | |
| 907 during the barrier sync and join it immediately afterwards. If we | |
| 908 do not do this, this then the following deadlock can occur: one | |
| 909 thread could be in the barrier sync code, waiting for the other | |
| 910 thread to also sync up, whereas another one could be trying to | |
| 911 yield, while also waiting for the other threads to sync up too. | |
| 912 | |
| 913 Because the thread that does the sync barrier has left the STS, it | |
| 914 is possible to be suspended for a Full GC or an evacuation pause | |
| 915 could occur. This is actually safe, since the entering the sync | |
| 916 barrier is one of the last things do_marking_step() does, and it | |
| 917 doesn't manipulate any data structures afterwards. | |
| 918 */ | |
| 919 | |
| 920 void ConcurrentMark::enter_first_sync_barrier(int task_num) { | |
| 921 if (verbose_low()) | |
| 922 gclog_or_tty->print_cr("[%d] entering first barrier", task_num); | |
| 923 | |
| 924 ConcurrentGCThread::stsLeave(); | |
| 925 _first_overflow_barrier_sync.enter(); | |
| 926 ConcurrentGCThread::stsJoin(); | |
| 927 // at this point everyone should have synced up and not be doing any | |
| 928 // more work | |
| 929 | |
| 930 if (verbose_low()) | |
| 931 gclog_or_tty->print_cr("[%d] leaving first barrier", task_num); | |
| 932 | |
| 933 // let task 0 do this | |
| 934 if (task_num == 0) { | |
| 935 // task 0 is responsible for clearing the global data structures | |
| 936 clear_marking_state(); | |
| 937 | |
| 938 if (PrintGC) { | |
| 939 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 940 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 941 gclog_or_tty->print_cr("[GC concurrent-mark-reset-for-overflow]"); | |
| 942 } | |
| 943 } | |
| 944 | |
| 945 // after this, each task should reset its own data structures then | |
| 946 // then go into the second barrier | |
| 947 } | |
| 948 | |
| 949 void ConcurrentMark::enter_second_sync_barrier(int task_num) { | |
| 950 if (verbose_low()) | |
| 951 gclog_or_tty->print_cr("[%d] entering second barrier", task_num); | |
| 952 | |
| 953 ConcurrentGCThread::stsLeave(); | |
| 954 _second_overflow_barrier_sync.enter(); | |
| 955 ConcurrentGCThread::stsJoin(); | |
| 956 // at this point everything should be re-initialised and ready to go | |
| 957 | |
| 958 if (verbose_low()) | |
| 959 gclog_or_tty->print_cr("[%d] leaving second barrier", task_num); | |
| 960 } | |
| 961 | |
| 962 void ConcurrentMark::grayRoot(oop p) { | |
| 963 HeapWord* addr = (HeapWord*) p; | |
| 964 // We can't really check against _heap_start and _heap_end, since it | |
| 965 // is possible during an evacuation pause with piggy-backed | |
| 966 // initial-mark that the committed space is expanded during the | |
| 967 // pause without CM observing this change. So the assertions below | |
| 968 // is a bit conservative; but better than nothing. | |
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969 assert(_g1h->g1_committed().contains(addr), |
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970 "address should be within the heap bounds"); |
| 342 | 971 |
| 972 if (!_nextMarkBitMap->isMarked(addr)) | |
| 973 _nextMarkBitMap->parMark(addr); | |
| 974 } | |
| 975 | |
| 976 void ConcurrentMark::grayRegionIfNecessary(MemRegion mr) { | |
| 977 // The objects on the region have already been marked "in bulk" by | |
| 978 // the caller. We only need to decide whether to push the region on | |
| 979 // the region stack or not. | |
| 980 | |
| 981 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 982 // We're done with marking and waiting for remark. We do not need to | |
| 983 // push anything else on the region stack. | |
| 984 return; | |
| 985 | |
| 986 HeapWord* finger = _finger; | |
| 987 | |
| 988 if (verbose_low()) | |
| 989 gclog_or_tty->print_cr("[global] attempting to push " | |
| 990 "region ["PTR_FORMAT", "PTR_FORMAT"), finger is at " | |
| 991 PTR_FORMAT, mr.start(), mr.end(), finger); | |
| 992 | |
| 993 if (mr.start() < finger) { | |
| 994 // The finger is always heap region aligned and it is not possible | |
| 995 // for mr to span heap regions. | |
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996 assert(mr.end() <= finger, "invariant"); |
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997 |
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998 // Separated the asserts so that we know which one fires. |
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999 assert(mr.start() <= mr.end(), |
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1000 "region boundaries should fall within the committed space"); |
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1001 assert(_heap_start <= mr.start(), |
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1002 "region boundaries should fall within the committed space"); |
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1003 assert(mr.end() <= _heap_end, |
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1004 "region boundaries should fall within the committed space"); |
| 342 | 1005 if (verbose_low()) |
| 1006 gclog_or_tty->print_cr("[global] region ["PTR_FORMAT", "PTR_FORMAT") " | |
| 1007 "below the finger, pushing it", | |
| 1008 mr.start(), mr.end()); | |
| 1009 | |
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1010 if (!region_stack_push_lock_free(mr)) { |
| 342 | 1011 if (verbose_low()) |
| 1012 gclog_or_tty->print_cr("[global] region stack has overflown."); | |
| 1013 } | |
| 1014 } | |
| 1015 } | |
| 1016 | |
| 1017 void ConcurrentMark::markAndGrayObjectIfNecessary(oop p) { | |
| 1018 // The object is not marked by the caller. We need to at least mark | |
| 1019 // it and maybe push in on the stack. | |
| 1020 | |
| 1021 HeapWord* addr = (HeapWord*)p; | |
| 1022 if (!_nextMarkBitMap->isMarked(addr)) { | |
| 1023 // We definitely need to mark it, irrespective whether we bail out | |
| 1024 // because we're done with marking. | |
| 1025 if (_nextMarkBitMap->parMark(addr)) { | |
| 1026 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 1027 // If we're done with concurrent marking and we're waiting for | |
| 1028 // remark, then we're not pushing anything on the stack. | |
| 1029 return; | |
| 1030 | |
| 1031 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 1032 // CAS done in parMark(addr) above | |
| 1033 HeapWord* finger = _finger; | |
| 1034 | |
| 1035 if (addr < finger) { | |
| 1036 if (!mark_stack_push(oop(addr))) { | |
| 1037 if (verbose_low()) | |
| 1038 gclog_or_tty->print_cr("[global] global stack overflow " | |
| 1039 "during parMark"); | |
| 1040 } | |
| 1041 } | |
| 1042 } | |
| 1043 } | |
| 1044 } | |
| 1045 | |
| 1046 class CMConcurrentMarkingTask: public AbstractGangTask { | |
| 1047 private: | |
| 1048 ConcurrentMark* _cm; | |
| 1049 ConcurrentMarkThread* _cmt; | |
| 1050 | |
| 1051 public: | |
| 1052 void work(int worker_i) { | |
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1053 assert(Thread::current()->is_ConcurrentGC_thread(), |
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1054 "this should only be done by a conc GC thread"); |
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1055 ResourceMark rm; |
| 342 | 1056 |
| 1057 double start_vtime = os::elapsedVTime(); | |
| 1058 | |
| 1059 ConcurrentGCThread::stsJoin(); | |
| 1060 | |
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1061 assert((size_t) worker_i < _cm->active_tasks(), "invariant"); |
| 342 | 1062 CMTask* the_task = _cm->task(worker_i); |
| 1063 the_task->record_start_time(); | |
| 1064 if (!_cm->has_aborted()) { | |
| 1065 do { | |
| 1066 double start_vtime_sec = os::elapsedVTime(); | |
| 1067 double start_time_sec = os::elapsedTime(); | |
| 1068 the_task->do_marking_step(10.0); | |
| 1069 double end_time_sec = os::elapsedTime(); | |
| 1070 double end_vtime_sec = os::elapsedVTime(); | |
| 1071 double elapsed_vtime_sec = end_vtime_sec - start_vtime_sec; | |
| 1072 double elapsed_time_sec = end_time_sec - start_time_sec; | |
| 1073 _cm->clear_has_overflown(); | |
| 1074 | |
| 1075 bool ret = _cm->do_yield_check(worker_i); | |
| 1076 | |
| 1077 jlong sleep_time_ms; | |
| 1078 if (!_cm->has_aborted() && the_task->has_aborted()) { | |
| 1079 sleep_time_ms = | |
| 1080 (jlong) (elapsed_vtime_sec * _cm->sleep_factor() * 1000.0); | |
| 1081 ConcurrentGCThread::stsLeave(); | |
| 1082 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1083 ConcurrentGCThread::stsJoin(); | |
| 1084 } | |
| 1085 double end_time2_sec = os::elapsedTime(); | |
| 1086 double elapsed_time2_sec = end_time2_sec - start_time_sec; | |
| 1087 | |
| 1088 #if 0 | |
| 1089 gclog_or_tty->print_cr("CM: elapsed %1.4lf ms, sleep %1.4lf ms, " | |
| 1090 "overhead %1.4lf", | |
| 1091 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms, | |
| 1092 the_task->conc_overhead(os::elapsedTime()) * 8.0); | |
| 1093 gclog_or_tty->print_cr("elapsed time %1.4lf ms, time 2: %1.4lf ms", | |
| 1094 elapsed_time_sec * 1000.0, elapsed_time2_sec * 1000.0); | |
| 1095 #endif | |
| 1096 } while (!_cm->has_aborted() && the_task->has_aborted()); | |
| 1097 } | |
| 1098 the_task->record_end_time(); | |
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1099 guarantee(!the_task->has_aborted() || _cm->has_aborted(), "invariant"); |
| 342 | 1100 |
| 1101 ConcurrentGCThread::stsLeave(); | |
| 1102 | |
| 1103 double end_vtime = os::elapsedVTime(); | |
| 1104 _cm->update_accum_task_vtime(worker_i, end_vtime - start_vtime); | |
| 1105 } | |
| 1106 | |
| 1107 CMConcurrentMarkingTask(ConcurrentMark* cm, | |
| 1108 ConcurrentMarkThread* cmt) : | |
| 1109 AbstractGangTask("Concurrent Mark"), _cm(cm), _cmt(cmt) { } | |
| 1110 | |
| 1111 ~CMConcurrentMarkingTask() { } | |
| 1112 }; | |
| 1113 | |
| 1114 void ConcurrentMark::markFromRoots() { | |
| 1115 // we might be tempted to assert that: | |
| 1116 // assert(asynch == !SafepointSynchronize::is_at_safepoint(), | |
| 1117 // "inconsistent argument?"); | |
| 1118 // However that wouldn't be right, because it's possible that | |
| 1119 // a safepoint is indeed in progress as a younger generation | |
| 1120 // stop-the-world GC happens even as we mark in this generation. | |
| 1121 | |
| 1122 _restart_for_overflow = false; | |
| 1123 | |
| 1124 set_phase(MAX2((size_t) 1, parallel_marking_threads()), true); | |
| 1125 | |
| 1126 CMConcurrentMarkingTask markingTask(this, cmThread()); | |
| 1127 if (parallel_marking_threads() > 0) | |
| 1128 _parallel_workers->run_task(&markingTask); | |
| 1129 else | |
| 1130 markingTask.work(0); | |
| 1131 print_stats(); | |
| 1132 } | |
| 1133 | |
| 1134 void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) { | |
| 1135 // world is stopped at this checkpoint | |
| 1136 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1137 "world should be stopped"); | |
| 1138 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1139 | |
| 1140 // If a full collection has happened, we shouldn't do this. | |
| 1141 if (has_aborted()) { | |
| 1142 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1143 return; | |
| 1144 } | |
| 1145 | |
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1146 SvcGCMarker sgcm(SvcGCMarker::OTHER); |
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1147 |
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1148 if (VerifyDuringGC) { |
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1149 HandleMark hm; // handle scope |
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1150 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1151 Universe::heap()->prepare_for_verify(); |
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1152 Universe::verify(true, false, true); |
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1153 } |
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1154 |
| 342 | 1155 G1CollectorPolicy* g1p = g1h->g1_policy(); |
| 1156 g1p->record_concurrent_mark_remark_start(); | |
| 1157 | |
| 1158 double start = os::elapsedTime(); | |
| 1159 | |
| 1160 checkpointRootsFinalWork(); | |
| 1161 | |
| 1162 double mark_work_end = os::elapsedTime(); | |
| 1163 | |
| 1164 weakRefsWork(clear_all_soft_refs); | |
| 1165 | |
| 1166 if (has_overflown()) { | |
| 1167 // Oops. We overflowed. Restart concurrent marking. | |
| 1168 _restart_for_overflow = true; | |
| 1169 // Clear the flag. We do not need it any more. | |
| 1170 clear_has_overflown(); | |
| 1171 if (G1TraceMarkStackOverflow) | |
| 1172 gclog_or_tty->print_cr("\nRemark led to restart for overflow."); | |
| 1173 } else { | |
| 1174 // We're done with marking. | |
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1175 // This is the end of the marking cycle, we're expected all |
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1176 // threads to have SATB queues with active set to true. |
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1177 JavaThread::satb_mark_queue_set().set_active_all_threads( |
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1178 false, /* new active value */ |
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1179 true /* expected_active */); |
| 811 | 1180 |
| 1181 if (VerifyDuringGC) { | |
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1182 HandleMark hm; // handle scope |
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1183 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1184 Universe::heap()->prepare_for_verify(); |
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1185 Universe::heap()->verify(/* allow_dirty */ true, |
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1186 /* silent */ false, |
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1187 /* use_prev_marking */ false); |
| 811 | 1188 } |
| 342 | 1189 } |
| 1190 | |
| 1191 #if VERIFY_OBJS_PROCESSED | |
| 1192 _scan_obj_cl.objs_processed = 0; | |
| 1193 ThreadLocalObjQueue::objs_enqueued = 0; | |
| 1194 #endif | |
| 1195 | |
| 1196 // Statistics | |
| 1197 double now = os::elapsedTime(); | |
| 1198 _remark_mark_times.add((mark_work_end - start) * 1000.0); | |
| 1199 _remark_weak_ref_times.add((now - mark_work_end) * 1000.0); | |
| 1200 _remark_times.add((now - start) * 1000.0); | |
| 1201 | |
| 1202 g1p->record_concurrent_mark_remark_end(); | |
| 1203 } | |
| 1204 | |
| 1205 | |
| 1206 #define CARD_BM_TEST_MODE 0 | |
| 1207 | |
| 1208 class CalcLiveObjectsClosure: public HeapRegionClosure { | |
| 1209 | |
| 1210 CMBitMapRO* _bm; | |
| 1211 ConcurrentMark* _cm; | |
| 1212 bool _changed; | |
| 1213 bool _yield; | |
| 1214 size_t _words_done; | |
| 1215 size_t _tot_live; | |
| 1216 size_t _tot_used; | |
| 1217 size_t _regions_done; | |
| 1218 double _start_vtime_sec; | |
| 1219 | |
| 1220 BitMap* _region_bm; | |
| 1221 BitMap* _card_bm; | |
| 1222 intptr_t _bottom_card_num; | |
| 1223 bool _final; | |
| 1224 | |
| 1225 void mark_card_num_range(intptr_t start_card_num, intptr_t last_card_num) { | |
| 1226 for (intptr_t i = start_card_num; i <= last_card_num; i++) { | |
| 1227 #if CARD_BM_TEST_MODE | |
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1228 guarantee(_card_bm->at(i - _bottom_card_num), "Should already be set."); |
| 342 | 1229 #else |
| 1230 _card_bm->par_at_put(i - _bottom_card_num, 1); | |
| 1231 #endif | |
| 1232 } | |
| 1233 } | |
| 1234 | |
| 1235 public: | |
| 1236 CalcLiveObjectsClosure(bool final, | |
| 1237 CMBitMapRO *bm, ConcurrentMark *cm, | |
| 936 | 1238 BitMap* region_bm, BitMap* card_bm) : |
| 342 | 1239 _bm(bm), _cm(cm), _changed(false), _yield(true), |
| 1240 _words_done(0), _tot_live(0), _tot_used(0), | |
| 936 | 1241 _region_bm(region_bm), _card_bm(card_bm),_final(final), |
| 342 | 1242 _regions_done(0), _start_vtime_sec(0.0) |
| 1243 { | |
| 1244 _bottom_card_num = | |
| 1245 intptr_t(uintptr_t(G1CollectedHeap::heap()->reserved_region().start()) >> | |
| 1246 CardTableModRefBS::card_shift); | |
| 1247 } | |
| 1248 | |
| 829 | 1249 // It takes a region that's not empty (i.e., it has at least one |
| 1250 // live object in it and sets its corresponding bit on the region | |
| 1251 // bitmap to 1. If the region is "starts humongous" it will also set | |
| 1252 // to 1 the bits on the region bitmap that correspond to its | |
| 1253 // associated "continues humongous" regions. | |
| 1254 void set_bit_for_region(HeapRegion* hr) { | |
| 1255 assert(!hr->continuesHumongous(), "should have filtered those out"); | |
| 1256 | |
| 1257 size_t index = hr->hrs_index(); | |
| 1258 if (!hr->startsHumongous()) { | |
| 1259 // Normal (non-humongous) case: just set the bit. | |
| 1260 _region_bm->par_at_put((BitMap::idx_t) index, true); | |
| 1261 } else { | |
| 1262 // Starts humongous case: calculate how many regions are part of | |
| 1263 // this humongous region and then set the bit range. It might | |
| 1264 // have been a bit more efficient to look at the object that | |
| 1265 // spans these humongous regions to calculate their number from | |
| 1266 // the object's size. However, it's a good idea to calculate | |
| 1267 // this based on the metadata itself, and not the region | |
| 1268 // contents, so that this code is not aware of what goes into | |
| 1269 // the humongous regions (in case this changes in the future). | |
| 1270 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1271 size_t end_index = index + 1; | |
| 831 | 1272 while (end_index < g1h->n_regions()) { |
| 1273 HeapRegion* chr = g1h->region_at(end_index); | |
| 829 | 1274 if (!chr->continuesHumongous()) { |
| 1275 break; | |
| 1276 } | |
| 1277 end_index += 1; | |
| 1278 } | |
| 1279 _region_bm->par_at_put_range((BitMap::idx_t) index, | |
| 1280 (BitMap::idx_t) end_index, true); | |
| 1281 } | |
| 1282 } | |
| 1283 | |
| 342 | 1284 bool doHeapRegion(HeapRegion* hr) { |
| 1285 if (!_final && _regions_done == 0) | |
| 1286 _start_vtime_sec = os::elapsedVTime(); | |
| 1287 | |
| 639 | 1288 if (hr->continuesHumongous()) { |
| 829 | 1289 // We will ignore these here and process them when their |
| 1290 // associated "starts humongous" region is processed (see | |
| 1291 // set_bit_for_heap_region()). Note that we cannot rely on their | |
| 1292 // associated "starts humongous" region to have their bit set to | |
| 1293 // 1 since, due to the region chunking in the parallel region | |
| 1294 // iteration, a "continues humongous" region might be visited | |
| 1295 // before its associated "starts humongous". | |
| 639 | 1296 return false; |
| 1297 } | |
| 342 | 1298 |
| 1299 HeapWord* nextTop = hr->next_top_at_mark_start(); | |
| 1300 HeapWord* start = hr->top_at_conc_mark_count(); | |
| 1301 assert(hr->bottom() <= start && start <= hr->end() && | |
| 1302 hr->bottom() <= nextTop && nextTop <= hr->end() && | |
| 1303 start <= nextTop, | |
| 1304 "Preconditions."); | |
| 1305 // Otherwise, record the number of word's we'll examine. | |
| 1306 size_t words_done = (nextTop - start); | |
| 1307 // Find the first marked object at or after "start". | |
| 1308 start = _bm->getNextMarkedWordAddress(start, nextTop); | |
| 1309 size_t marked_bytes = 0; | |
| 1310 | |
| 1311 // Below, the term "card num" means the result of shifting an address | |
| 1312 // by the card shift -- address 0 corresponds to card number 0. One | |
| 1313 // must subtract the card num of the bottom of the heap to obtain a | |
| 1314 // card table index. | |
| 1315 // The first card num of the sequence of live cards currently being | |
| 1316 // constructed. -1 ==> no sequence. | |
| 1317 intptr_t start_card_num = -1; | |
| 1318 // The last card num of the sequence of live cards currently being | |
| 1319 // constructed. -1 ==> no sequence. | |
| 1320 intptr_t last_card_num = -1; | |
| 1321 | |
| 1322 while (start < nextTop) { | |
| 1323 if (_yield && _cm->do_yield_check()) { | |
| 1324 // We yielded. It might be for a full collection, in which case | |
| 1325 // all bets are off; terminate the traversal. | |
| 1326 if (_cm->has_aborted()) { | |
| 1327 _changed = false; | |
| 1328 return true; | |
| 1329 } else { | |
| 1330 // Otherwise, it might be a collection pause, and the region | |
| 1331 // we're looking at might be in the collection set. We'll | |
| 1332 // abandon this region. | |
| 1333 return false; | |
| 1334 } | |
| 1335 } | |
| 1336 oop obj = oop(start); | |
| 1337 int obj_sz = obj->size(); | |
| 1338 // The card num of the start of the current object. | |
| 1339 intptr_t obj_card_num = | |
| 1340 intptr_t(uintptr_t(start) >> CardTableModRefBS::card_shift); | |
| 1341 | |
| 1342 HeapWord* obj_last = start + obj_sz - 1; | |
| 1343 intptr_t obj_last_card_num = | |
| 1344 intptr_t(uintptr_t(obj_last) >> CardTableModRefBS::card_shift); | |
| 1345 | |
| 1346 if (obj_card_num != last_card_num) { | |
| 1347 if (start_card_num == -1) { | |
| 1348 assert(last_card_num == -1, "Both or neither."); | |
| 1349 start_card_num = obj_card_num; | |
| 1350 } else { | |
| 1351 assert(last_card_num != -1, "Both or neither."); | |
| 1352 assert(obj_card_num >= last_card_num, "Inv"); | |
| 1353 if ((obj_card_num - last_card_num) > 1) { | |
| 1354 // Mark the last run, and start a new one. | |
| 1355 mark_card_num_range(start_card_num, last_card_num); | |
| 1356 start_card_num = obj_card_num; | |
| 1357 } | |
| 1358 } | |
| 1359 #if CARD_BM_TEST_MODE | |
| 1360 /* | |
| 1361 gclog_or_tty->print_cr("Setting bits from %d/%d.", | |
| 1362 obj_card_num - _bottom_card_num, | |
| 1363 obj_last_card_num - _bottom_card_num); | |
| 1364 */ | |
| 1365 for (intptr_t j = obj_card_num; j <= obj_last_card_num; j++) { | |
| 1366 _card_bm->par_at_put(j - _bottom_card_num, 1); | |
| 1367 } | |
| 1368 #endif | |
| 1369 } | |
| 1370 // In any case, we set the last card num. | |
| 1371 last_card_num = obj_last_card_num; | |
| 1372 | |
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1373 marked_bytes += (size_t)obj_sz * HeapWordSize; |
| 342 | 1374 // Find the next marked object after this one. |
| 1375 start = _bm->getNextMarkedWordAddress(start + 1, nextTop); | |
| 1376 _changed = true; | |
| 1377 } | |
| 1378 // Handle the last range, if any. | |
| 1379 if (start_card_num != -1) | |
| 1380 mark_card_num_range(start_card_num, last_card_num); | |
| 1381 if (_final) { | |
| 1382 // Mark the allocated-since-marking portion... | |
| 1383 HeapWord* tp = hr->top(); | |
| 1384 if (nextTop < tp) { | |
| 1385 start_card_num = | |
| 1386 intptr_t(uintptr_t(nextTop) >> CardTableModRefBS::card_shift); | |
| 1387 last_card_num = | |
| 1388 intptr_t(uintptr_t(tp) >> CardTableModRefBS::card_shift); | |
| 1389 mark_card_num_range(start_card_num, last_card_num); | |
| 1390 // This definitely means the region has live objects. | |
| 829 | 1391 set_bit_for_region(hr); |
| 342 | 1392 } |
| 1393 } | |
| 1394 | |
| 1395 hr->add_to_marked_bytes(marked_bytes); | |
| 1396 // Update the live region bitmap. | |
| 1397 if (marked_bytes > 0) { | |
| 829 | 1398 set_bit_for_region(hr); |
| 342 | 1399 } |
| 1400 hr->set_top_at_conc_mark_count(nextTop); | |
| 1401 _tot_live += hr->next_live_bytes(); | |
| 1402 _tot_used += hr->used(); | |
| 1403 _words_done = words_done; | |
| 1404 | |
| 1405 if (!_final) { | |
| 1406 ++_regions_done; | |
| 1407 if (_regions_done % 10 == 0) { | |
| 1408 double end_vtime_sec = os::elapsedVTime(); | |
| 1409 double elapsed_vtime_sec = end_vtime_sec - _start_vtime_sec; | |
| 1410 if (elapsed_vtime_sec > (10.0 / 1000.0)) { | |
| 1411 jlong sleep_time_ms = | |
| 1412 (jlong) (elapsed_vtime_sec * _cm->cleanup_sleep_factor() * 1000.0); | |
| 1413 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1414 _start_vtime_sec = end_vtime_sec; | |
| 1415 } | |
| 1416 } | |
| 1417 } | |
| 1418 | |
| 1419 return false; | |
| 1420 } | |
| 1421 | |
| 1422 bool changed() { return _changed; } | |
| 1423 void reset() { _changed = false; _words_done = 0; } | |
| 1424 void no_yield() { _yield = false; } | |
| 1425 size_t words_done() { return _words_done; } | |
| 1426 size_t tot_live() { return _tot_live; } | |
| 1427 size_t tot_used() { return _tot_used; } | |
| 1428 }; | |
| 1429 | |
| 1430 | |
| 1431 void ConcurrentMark::calcDesiredRegions() { | |
| 1432 _region_bm.clear(); | |
| 1433 _card_bm.clear(); | |
| 1434 CalcLiveObjectsClosure calccl(false /*final*/, | |
| 1435 nextMarkBitMap(), this, | |
| 936 | 1436 &_region_bm, &_card_bm); |
| 342 | 1437 G1CollectedHeap *g1h = G1CollectedHeap::heap(); |
| 1438 g1h->heap_region_iterate(&calccl); | |
| 1439 | |
| 1440 do { | |
| 1441 calccl.reset(); | |
| 1442 g1h->heap_region_iterate(&calccl); | |
| 1443 } while (calccl.changed()); | |
| 1444 } | |
| 1445 | |
| 1446 class G1ParFinalCountTask: public AbstractGangTask { | |
| 1447 protected: | |
| 1448 G1CollectedHeap* _g1h; | |
| 1449 CMBitMap* _bm; | |
| 1450 size_t _n_workers; | |
| 1451 size_t *_live_bytes; | |
| 1452 size_t *_used_bytes; | |
| 1453 BitMap* _region_bm; | |
| 1454 BitMap* _card_bm; | |
| 1455 public: | |
| 1456 G1ParFinalCountTask(G1CollectedHeap* g1h, CMBitMap* bm, | |
| 1457 BitMap* region_bm, BitMap* card_bm) : | |
| 1458 AbstractGangTask("G1 final counting"), _g1h(g1h), | |
| 1459 _bm(bm), _region_bm(region_bm), _card_bm(card_bm) | |
| 1460 { | |
| 1461 if (ParallelGCThreads > 0) | |
| 1462 _n_workers = _g1h->workers()->total_workers(); | |
| 1463 else | |
| 1464 _n_workers = 1; | |
| 1465 _live_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1466 _used_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1467 } | |
| 1468 | |
| 1469 ~G1ParFinalCountTask() { | |
| 1470 FREE_C_HEAP_ARRAY(size_t, _live_bytes); | |
| 1471 FREE_C_HEAP_ARRAY(size_t, _used_bytes); | |
| 1472 } | |
| 1473 | |
| 1474 void work(int i) { | |
| 1475 CalcLiveObjectsClosure calccl(true /*final*/, | |
| 1476 _bm, _g1h->concurrent_mark(), | |
| 936 | 1477 _region_bm, _card_bm); |
| 342 | 1478 calccl.no_yield(); |
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1479 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1480 _g1h->heap_region_par_iterate_chunked(&calccl, i, |
| 1481 HeapRegion::FinalCountClaimValue); | |
| 342 | 1482 } else { |
| 1483 _g1h->heap_region_iterate(&calccl); | |
| 1484 } | |
| 1485 assert(calccl.complete(), "Shouldn't have yielded!"); | |
| 1486 | |
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1487 assert((size_t) i < _n_workers, "invariant"); |
| 342 | 1488 _live_bytes[i] = calccl.tot_live(); |
| 1489 _used_bytes[i] = calccl.tot_used(); | |
| 1490 } | |
| 1491 size_t live_bytes() { | |
| 1492 size_t live_bytes = 0; | |
| 1493 for (size_t i = 0; i < _n_workers; ++i) | |
| 1494 live_bytes += _live_bytes[i]; | |
| 1495 return live_bytes; | |
| 1496 } | |
| 1497 size_t used_bytes() { | |
| 1498 size_t used_bytes = 0; | |
| 1499 for (size_t i = 0; i < _n_workers; ++i) | |
| 1500 used_bytes += _used_bytes[i]; | |
| 1501 return used_bytes; | |
| 1502 } | |
| 1503 }; | |
| 1504 | |
| 1505 class G1ParNoteEndTask; | |
| 1506 | |
| 1507 class G1NoteEndOfConcMarkClosure : public HeapRegionClosure { | |
| 1508 G1CollectedHeap* _g1; | |
| 1509 int _worker_num; | |
| 1510 size_t _max_live_bytes; | |
| 1511 size_t _regions_claimed; | |
| 1512 size_t _freed_bytes; | |
| 1513 size_t _cleared_h_regions; | |
| 1514 size_t _freed_regions; | |
| 1515 UncleanRegionList* _unclean_region_list; | |
| 1516 double _claimed_region_time; | |
| 1517 double _max_region_time; | |
| 1518 | |
| 1519 public: | |
| 1520 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1521 UncleanRegionList* list, | |
| 1522 int worker_num); | |
| 1523 size_t freed_bytes() { return _freed_bytes; } | |
| 1524 size_t cleared_h_regions() { return _cleared_h_regions; } | |
| 1525 size_t freed_regions() { return _freed_regions; } | |
| 1526 UncleanRegionList* unclean_region_list() { | |
| 1527 return _unclean_region_list; | |
| 1528 } | |
| 1529 | |
| 1530 bool doHeapRegion(HeapRegion *r); | |
| 1531 | |
| 1532 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1533 size_t regions_claimed() { return _regions_claimed; } | |
| 1534 double claimed_region_time_sec() { return _claimed_region_time; } | |
| 1535 double max_region_time_sec() { return _max_region_time; } | |
| 1536 }; | |
| 1537 | |
| 1538 class G1ParNoteEndTask: public AbstractGangTask { | |
| 1539 friend class G1NoteEndOfConcMarkClosure; | |
| 1540 protected: | |
| 1541 G1CollectedHeap* _g1h; | |
| 1542 size_t _max_live_bytes; | |
| 1543 size_t _freed_bytes; | |
| 1544 ConcurrentMark::ParCleanupThreadState** _par_cleanup_thread_state; | |
| 1545 public: | |
| 1546 G1ParNoteEndTask(G1CollectedHeap* g1h, | |
| 1547 ConcurrentMark::ParCleanupThreadState** | |
| 1548 par_cleanup_thread_state) : | |
| 1549 AbstractGangTask("G1 note end"), _g1h(g1h), | |
| 1550 _max_live_bytes(0), _freed_bytes(0), | |
| 1551 _par_cleanup_thread_state(par_cleanup_thread_state) | |
| 1552 {} | |
| 1553 | |
| 1554 void work(int i) { | |
| 1555 double start = os::elapsedTime(); | |
| 1556 G1NoteEndOfConcMarkClosure g1_note_end(_g1h, | |
| 1557 &_par_cleanup_thread_state[i]->list, | |
| 1558 i); | |
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1559 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1560 _g1h->heap_region_par_iterate_chunked(&g1_note_end, i, |
| 1561 HeapRegion::NoteEndClaimValue); | |
| 342 | 1562 } else { |
| 1563 _g1h->heap_region_iterate(&g1_note_end); | |
| 1564 } | |
| 1565 assert(g1_note_end.complete(), "Shouldn't have yielded!"); | |
| 1566 | |
| 1567 // Now finish up freeing the current thread's regions. | |
| 1568 _g1h->finish_free_region_work(g1_note_end.freed_bytes(), | |
| 1569 g1_note_end.cleared_h_regions(), | |
| 1570 0, NULL); | |
| 1571 { | |
| 1572 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 1573 _max_live_bytes += g1_note_end.max_live_bytes(); | |
| 1574 _freed_bytes += g1_note_end.freed_bytes(); | |
| 1575 } | |
| 1576 double end = os::elapsedTime(); | |
| 1577 if (G1PrintParCleanupStats) { | |
| 1578 gclog_or_tty->print(" Worker thread %d [%8.3f..%8.3f = %8.3f ms] " | |
| 1579 "claimed %d regions (tot = %8.3f ms, max = %8.3f ms).\n", | |
| 1580 i, start, end, (end-start)*1000.0, | |
| 1581 g1_note_end.regions_claimed(), | |
| 1582 g1_note_end.claimed_region_time_sec()*1000.0, | |
| 1583 g1_note_end.max_region_time_sec()*1000.0); | |
| 1584 } | |
| 1585 } | |
| 1586 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1587 size_t freed_bytes() { return _freed_bytes; } | |
| 1588 }; | |
| 1589 | |
| 1590 class G1ParScrubRemSetTask: public AbstractGangTask { | |
| 1591 protected: | |
| 1592 G1RemSet* _g1rs; | |
| 1593 BitMap* _region_bm; | |
| 1594 BitMap* _card_bm; | |
| 1595 public: | |
| 1596 G1ParScrubRemSetTask(G1CollectedHeap* g1h, | |
| 1597 BitMap* region_bm, BitMap* card_bm) : | |
| 1598 AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()), | |
| 1599 _region_bm(region_bm), _card_bm(card_bm) | |
| 1600 {} | |
| 1601 | |
| 1602 void work(int i) { | |
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1603 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1604 _g1rs->scrub_par(_region_bm, _card_bm, i, |
| 1605 HeapRegion::ScrubRemSetClaimValue); | |
| 342 | 1606 } else { |
| 1607 _g1rs->scrub(_region_bm, _card_bm); | |
| 1608 } | |
| 1609 } | |
| 1610 | |
| 1611 }; | |
| 1612 | |
| 1613 G1NoteEndOfConcMarkClosure:: | |
| 1614 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1615 UncleanRegionList* list, | |
| 1616 int worker_num) | |
| 1617 : _g1(g1), _worker_num(worker_num), | |
| 1618 _max_live_bytes(0), _regions_claimed(0), | |
| 1619 _freed_bytes(0), _cleared_h_regions(0), _freed_regions(0), | |
| 1620 _claimed_region_time(0.0), _max_region_time(0.0), | |
| 1621 _unclean_region_list(list) | |
| 1622 {} | |
| 1623 | |
| 1624 bool G1NoteEndOfConcMarkClosure::doHeapRegion(HeapRegion *r) { | |
| 1625 // We use a claim value of zero here because all regions | |
| 1626 // were claimed with value 1 in the FinalCount task. | |
| 1627 r->reset_gc_time_stamp(); | |
| 1628 if (!r->continuesHumongous()) { | |
| 1629 double start = os::elapsedTime(); | |
| 1630 _regions_claimed++; | |
| 1631 r->note_end_of_marking(); | |
| 1632 _max_live_bytes += r->max_live_bytes(); | |
| 1633 _g1->free_region_if_totally_empty_work(r, | |
| 1634 _freed_bytes, | |
| 1635 _cleared_h_regions, | |
| 1636 _freed_regions, | |
| 1637 _unclean_region_list, | |
| 1638 true /*par*/); | |
| 1639 double region_time = (os::elapsedTime() - start); | |
| 1640 _claimed_region_time += region_time; | |
| 1641 if (region_time > _max_region_time) _max_region_time = region_time; | |
| 1642 } | |
| 1643 return false; | |
| 1644 } | |
| 1645 | |
| 1646 void ConcurrentMark::cleanup() { | |
| 1647 // world is stopped at this checkpoint | |
| 1648 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1649 "world should be stopped"); | |
| 1650 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1651 | |
| 1652 // If a full collection has happened, we shouldn't do this. | |
| 1653 if (has_aborted()) { | |
| 1654 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1655 return; | |
| 1656 } | |
| 1657 | |
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1658 if (VerifyDuringGC) { |
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1659 HandleMark hm; // handle scope |
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1660 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1661 Universe::heap()->prepare_for_verify(); |
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1662 Universe::verify(/* allow dirty */ true, |
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1663 /* silent */ false, |
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1664 /* prev marking */ true); |
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1665 } |
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1666 |
| 342 | 1667 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); |
| 1668 g1p->record_concurrent_mark_cleanup_start(); | |
| 1669 | |
| 1670 double start = os::elapsedTime(); | |
| 1671 | |
| 1672 // Do counting once more with the world stopped for good measure. | |
| 1673 G1ParFinalCountTask g1_par_count_task(g1h, nextMarkBitMap(), | |
| 1674 &_region_bm, &_card_bm); | |
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1675 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1676 assert(g1h->check_heap_region_claim_values( |
| 1677 HeapRegion::InitialClaimValue), | |
| 1678 "sanity check"); | |
| 1679 | |
| 342 | 1680 int n_workers = g1h->workers()->total_workers(); |
| 1681 g1h->set_par_threads(n_workers); | |
| 1682 g1h->workers()->run_task(&g1_par_count_task); | |
| 1683 g1h->set_par_threads(0); | |
| 355 | 1684 |
| 1685 assert(g1h->check_heap_region_claim_values( | |
| 1686 HeapRegion::FinalCountClaimValue), | |
| 1687 "sanity check"); | |
| 342 | 1688 } else { |
| 1689 g1_par_count_task.work(0); | |
| 1690 } | |
| 1691 | |
| 1692 size_t known_garbage_bytes = | |
| 1693 g1_par_count_task.used_bytes() - g1_par_count_task.live_bytes(); | |
| 1694 #if 0 | |
| 1695 gclog_or_tty->print_cr("used %1.2lf, live %1.2lf, garbage %1.2lf", | |
| 1696 (double) g1_par_count_task.used_bytes() / (double) (1024 * 1024), | |
| 1697 (double) g1_par_count_task.live_bytes() / (double) (1024 * 1024), | |
| 1698 (double) known_garbage_bytes / (double) (1024 * 1024)); | |
| 1699 #endif // 0 | |
| 1700 g1p->set_known_garbage_bytes(known_garbage_bytes); | |
| 1701 | |
| 1702 size_t start_used_bytes = g1h->used(); | |
| 1703 _at_least_one_mark_complete = true; | |
| 1704 g1h->set_marking_complete(); | |
| 1705 | |
| 1706 double count_end = os::elapsedTime(); | |
| 1707 double this_final_counting_time = (count_end - start); | |
| 1708 if (G1PrintParCleanupStats) { | |
| 1709 gclog_or_tty->print_cr("Cleanup:"); | |
| 1710 gclog_or_tty->print_cr(" Finalize counting: %8.3f ms", | |
| 1711 this_final_counting_time*1000.0); | |
| 1712 } | |
| 1713 _total_counting_time += this_final_counting_time; | |
| 1714 | |
| 1715 // Install newly created mark bitMap as "prev". | |
| 1716 swapMarkBitMaps(); | |
| 1717 | |
| 1718 g1h->reset_gc_time_stamp(); | |
| 1719 | |
| 1720 // Note end of marking in all heap regions. | |
| 1721 double note_end_start = os::elapsedTime(); | |
| 1722 G1ParNoteEndTask g1_par_note_end_task(g1h, _par_cleanup_thread_state); | |
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1723 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 1724 int n_workers = g1h->workers()->total_workers(); |
| 1725 g1h->set_par_threads(n_workers); | |
| 1726 g1h->workers()->run_task(&g1_par_note_end_task); | |
| 1727 g1h->set_par_threads(0); | |
| 355 | 1728 |
| 1729 assert(g1h->check_heap_region_claim_values(HeapRegion::NoteEndClaimValue), | |
| 1730 "sanity check"); | |
| 342 | 1731 } else { |
| 1732 g1_par_note_end_task.work(0); | |
| 1733 } | |
| 1734 g1h->set_unclean_regions_coming(true); | |
| 1735 double note_end_end = os::elapsedTime(); | |
| 1736 // Tell the mutators that there might be unclean regions coming... | |
| 1737 if (G1PrintParCleanupStats) { | |
| 1738 gclog_or_tty->print_cr(" note end of marking: %8.3f ms.", | |
| 1739 (note_end_end - note_end_start)*1000.0); | |
| 1740 } | |
| 1741 | |
| 355 | 1742 |
| 342 | 1743 // call below, since it affects the metric by which we sort the heap |
| 1744 // regions. | |
| 1745 if (G1ScrubRemSets) { | |
| 1746 double rs_scrub_start = os::elapsedTime(); | |
| 1747 G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm); | |
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1748 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 1749 int n_workers = g1h->workers()->total_workers(); |
| 1750 g1h->set_par_threads(n_workers); | |
| 1751 g1h->workers()->run_task(&g1_par_scrub_rs_task); | |
| 1752 g1h->set_par_threads(0); | |
| 355 | 1753 |
| 1754 assert(g1h->check_heap_region_claim_values( | |
| 1755 HeapRegion::ScrubRemSetClaimValue), | |
| 1756 "sanity check"); | |
| 342 | 1757 } else { |
| 1758 g1_par_scrub_rs_task.work(0); | |
| 1759 } | |
| 1760 | |
| 1761 double rs_scrub_end = os::elapsedTime(); | |
| 1762 double this_rs_scrub_time = (rs_scrub_end - rs_scrub_start); | |
| 1763 _total_rs_scrub_time += this_rs_scrub_time; | |
| 1764 } | |
| 1765 | |
| 1766 // this will also free any regions totally full of garbage objects, | |
| 1767 // and sort the regions. | |
| 1768 g1h->g1_policy()->record_concurrent_mark_cleanup_end( | |
| 1769 g1_par_note_end_task.freed_bytes(), | |
| 1770 g1_par_note_end_task.max_live_bytes()); | |
| 1771 | |
| 1772 // Statistics. | |
| 1773 double end = os::elapsedTime(); | |
| 1774 _cleanup_times.add((end - start) * 1000.0); | |
| 1775 | |
| 1776 // G1CollectedHeap::heap()->print(); | |
| 1777 // gclog_or_tty->print_cr("HEAP GC TIME STAMP : %d", | |
| 1778 // G1CollectedHeap::heap()->get_gc_time_stamp()); | |
| 1779 | |
| 1780 if (PrintGC || PrintGCDetails) { | |
| 1781 g1h->print_size_transition(gclog_or_tty, | |
| 1782 start_used_bytes, | |
| 1783 g1h->used(), | |
| 1784 g1h->capacity()); | |
| 1785 } | |
| 1786 | |
| 1787 size_t cleaned_up_bytes = start_used_bytes - g1h->used(); | |
| 1788 g1p->decrease_known_garbage_bytes(cleaned_up_bytes); | |
| 1789 | |
| 1790 // We need to make this be a "collection" so any collection pause that | |
| 1791 // races with it goes around and waits for completeCleanup to finish. | |
| 1792 g1h->increment_total_collections(); | |
| 1793 | |
| 751 | 1794 if (VerifyDuringGC) { |
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1795 HandleMark hm; // handle scope |
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1796 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1797 Universe::heap()->prepare_for_verify(); |
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1798 Universe::verify(/* allow dirty */ true, |
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1799 /* silent */ false, |
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1800 /* prev marking */ true); |
| 342 | 1801 } |
| 1802 } | |
| 1803 | |
| 1804 void ConcurrentMark::completeCleanup() { | |
| 1805 // A full collection intervened. | |
| 1806 if (has_aborted()) return; | |
| 1807 | |
| 1808 int first = 0; | |
| 1809 int last = (int)MAX2(ParallelGCThreads, (size_t)1); | |
| 1810 for (int t = 0; t < last; t++) { | |
| 1811 UncleanRegionList* list = &_par_cleanup_thread_state[t]->list; | |
| 1812 assert(list->well_formed(), "Inv"); | |
| 1813 HeapRegion* hd = list->hd(); | |
| 1814 while (hd != NULL) { | |
| 1815 // Now finish up the other stuff. | |
| 1816 hd->rem_set()->clear(); | |
| 1817 HeapRegion* next_hd = hd->next_from_unclean_list(); | |
| 1818 (void)list->pop(); | |
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1819 assert(list->hd() == next_hd, "how not?"); |
| 342 | 1820 _g1h->put_region_on_unclean_list(hd); |
| 1821 if (!hd->isHumongous()) { | |
| 1822 // Add this to the _free_regions count by 1. | |
| 1823 _g1h->finish_free_region_work(0, 0, 1, NULL); | |
| 1824 } | |
| 1825 hd = list->hd(); | |
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1826 assert(hd == next_hd, "how not?"); |
| 342 | 1827 } |
| 1828 } | |
| 1829 } | |
| 1830 | |
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1831 bool G1CMIsAliveClosure::do_object_b(oop obj) { |
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1832 HeapWord* addr = (HeapWord*)obj; |
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1833 return addr != NULL && |
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1834 (!_g1->is_in_g1_reserved(addr) || !_g1->is_obj_ill(obj)); |
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1835 } |
| 342 | 1836 |
| 1837 class G1CMKeepAliveClosure: public OopClosure { | |
| 1838 G1CollectedHeap* _g1; | |
| 1839 ConcurrentMark* _cm; | |
| 1840 CMBitMap* _bitMap; | |
| 1841 public: | |
| 1842 G1CMKeepAliveClosure(G1CollectedHeap* g1, ConcurrentMark* cm, | |
| 1843 CMBitMap* bitMap) : | |
| 1844 _g1(g1), _cm(cm), | |
| 1845 _bitMap(bitMap) {} | |
| 1846 | |
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1847 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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1848 virtual void do_oop( oop* p) { do_oop_work(p); } |
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1849 |
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1850 template <class T> void do_oop_work(T* p) { |
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1851 oop thisOop = oopDesc::load_decode_heap_oop(p); |
| 342 | 1852 HeapWord* addr = (HeapWord*)thisOop; |
| 1853 if (_g1->is_in_g1_reserved(addr) && _g1->is_obj_ill(thisOop)) { | |
| 1854 _bitMap->mark(addr); | |
| 1855 _cm->mark_stack_push(thisOop); | |
| 1856 } | |
| 1857 } | |
| 1858 }; | |
| 1859 | |
| 1860 class G1CMDrainMarkingStackClosure: public VoidClosure { | |
| 1861 CMMarkStack* _markStack; | |
| 1862 CMBitMap* _bitMap; | |
| 1863 G1CMKeepAliveClosure* _oopClosure; | |
| 1864 public: | |
| 1865 G1CMDrainMarkingStackClosure(CMBitMap* bitMap, CMMarkStack* markStack, | |
| 1866 G1CMKeepAliveClosure* oopClosure) : | |
| 1867 _bitMap(bitMap), | |
| 1868 _markStack(markStack), | |
| 1869 _oopClosure(oopClosure) | |
| 1870 {} | |
| 1871 | |
| 1872 void do_void() { | |
| 1873 _markStack->drain((OopClosure*)_oopClosure, _bitMap, false); | |
| 1874 } | |
| 1875 }; | |
| 1876 | |
| 1877 void ConcurrentMark::weakRefsWork(bool clear_all_soft_refs) { | |
| 1878 ResourceMark rm; | |
| 1879 HandleMark hm; | |
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1880 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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1881 ReferenceProcessor* rp = g1h->ref_processor(); |
| 342 | 1882 |
|
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1883 // See the comment in G1CollectedHeap::ref_processing_init() |
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1884 // about how reference processing currently works in G1. |
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1885 |
| 342 | 1886 // Process weak references. |
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1887 rp->setup_policy(clear_all_soft_refs); |
| 342 | 1888 assert(_markStack.isEmpty(), "mark stack should be empty"); |
| 1889 | |
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1890 G1CMIsAliveClosure g1_is_alive(g1h); |
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1891 G1CMKeepAliveClosure g1_keep_alive(g1h, this, nextMarkBitMap()); |
| 342 | 1892 G1CMDrainMarkingStackClosure |
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1893 g1_drain_mark_stack(nextMarkBitMap(), &_markStack, &g1_keep_alive); |
| 342 | 1894 |
| 1895 // XXXYYY Also: copy the parallel ref processing code from CMS. | |
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1896 rp->process_discovered_references(&g1_is_alive, |
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1897 &g1_keep_alive, |
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1898 &g1_drain_mark_stack, |
| 342 | 1899 NULL); |
| 1900 assert(_markStack.overflow() || _markStack.isEmpty(), | |
| 1901 "mark stack should be empty (unless it overflowed)"); | |
| 1902 if (_markStack.overflow()) { | |
| 1903 set_has_overflown(); | |
| 1904 } | |
| 1905 | |
| 1906 rp->enqueue_discovered_references(); | |
| 1907 rp->verify_no_references_recorded(); | |
| 1908 assert(!rp->discovery_enabled(), "should have been disabled"); | |
| 1909 | |
| 1910 // Now clean up stale oops in SymbolTable and StringTable | |
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1911 SymbolTable::unlink(&g1_is_alive); |
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1912 StringTable::unlink(&g1_is_alive); |
| 342 | 1913 } |
| 1914 | |
| 1915 void ConcurrentMark::swapMarkBitMaps() { | |
| 1916 CMBitMapRO* temp = _prevMarkBitMap; | |
| 1917 _prevMarkBitMap = (CMBitMapRO*)_nextMarkBitMap; | |
| 1918 _nextMarkBitMap = (CMBitMap*) temp; | |
| 1919 } | |
| 1920 | |
| 1921 class CMRemarkTask: public AbstractGangTask { | |
| 1922 private: | |
| 1923 ConcurrentMark *_cm; | |
| 1924 | |
| 1925 public: | |
| 1926 void work(int worker_i) { | |
| 1927 // Since all available tasks are actually started, we should | |
| 1928 // only proceed if we're supposed to be actived. | |
| 1929 if ((size_t)worker_i < _cm->active_tasks()) { | |
| 1930 CMTask* task = _cm->task(worker_i); | |
| 1931 task->record_start_time(); | |
| 1932 do { | |
| 1933 task->do_marking_step(1000000000.0 /* something very large */); | |
| 1934 } while (task->has_aborted() && !_cm->has_overflown()); | |
| 1935 // If we overflow, then we do not want to restart. We instead | |
| 1936 // want to abort remark and do concurrent marking again. | |
| 1937 task->record_end_time(); | |
| 1938 } | |
| 1939 } | |
| 1940 | |
| 1941 CMRemarkTask(ConcurrentMark* cm) : | |
| 1942 AbstractGangTask("Par Remark"), _cm(cm) { } | |
| 1943 }; | |
| 1944 | |
| 1945 void ConcurrentMark::checkpointRootsFinalWork() { | |
| 1946 ResourceMark rm; | |
| 1947 HandleMark hm; | |
| 1948 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1949 | |
| 1950 g1h->ensure_parsability(false); | |
| 1951 | |
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1952 if (G1CollectedHeap::use_parallel_gc_threads()) { |
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1953 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1954 // this is remark, so we'll use up all available threads |
| 1955 int active_workers = ParallelGCThreads; | |
| 1956 set_phase(active_workers, false); | |
| 1957 | |
| 1958 CMRemarkTask remarkTask(this); | |
| 1959 // We will start all available threads, even if we decide that the | |
| 1960 // active_workers will be fewer. The extra ones will just bail out | |
| 1961 // immediately. | |
| 1962 int n_workers = g1h->workers()->total_workers(); | |
| 1963 g1h->set_par_threads(n_workers); | |
| 1964 g1h->workers()->run_task(&remarkTask); | |
| 1965 g1h->set_par_threads(0); | |
| 1966 } else { | |
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1967 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1968 // this is remark, so we'll use up all available threads |
| 1969 int active_workers = 1; | |
| 1970 set_phase(active_workers, false); | |
| 1971 | |
| 1972 CMRemarkTask remarkTask(this); | |
| 1973 // We will start all available threads, even if we decide that the | |
| 1974 // active_workers will be fewer. The extra ones will just bail out | |
| 1975 // immediately. | |
| 1976 remarkTask.work(0); | |
| 1977 } | |
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1978 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); |
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1979 guarantee(satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 1980 |
| 1981 print_stats(); | |
| 1982 | |
| 1983 if (!restart_for_overflow()) | |
| 1984 set_non_marking_state(); | |
| 1985 | |
| 1986 #if VERIFY_OBJS_PROCESSED | |
| 1987 if (_scan_obj_cl.objs_processed != ThreadLocalObjQueue::objs_enqueued) { | |
| 1988 gclog_or_tty->print_cr("Processed = %d, enqueued = %d.", | |
| 1989 _scan_obj_cl.objs_processed, | |
| 1990 ThreadLocalObjQueue::objs_enqueued); | |
| 1991 guarantee(_scan_obj_cl.objs_processed == | |
| 1992 ThreadLocalObjQueue::objs_enqueued, | |
| 1993 "Different number of objs processed and enqueued."); | |
| 1994 } | |
| 1995 #endif | |
| 1996 } | |
| 1997 | |
| 1044 | 1998 #ifndef PRODUCT |
| 1999 | |
| 1388 | 2000 class PrintReachableOopClosure: public OopClosure { |
| 342 | 2001 private: |
| 2002 G1CollectedHeap* _g1h; | |
| 2003 CMBitMapRO* _bitmap; | |
| 2004 outputStream* _out; | |
| 1044 | 2005 bool _use_prev_marking; |
| 1388 | 2006 bool _all; |
| 342 | 2007 |
| 2008 public: | |
| 1388 | 2009 PrintReachableOopClosure(CMBitMapRO* bitmap, |
| 2010 outputStream* out, | |
| 2011 bool use_prev_marking, | |
| 2012 bool all) : | |
| 1044 | 2013 _g1h(G1CollectedHeap::heap()), |
| 1388 | 2014 _bitmap(bitmap), _out(out), _use_prev_marking(use_prev_marking), _all(all) { } |
| 342 | 2015 |
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2016 void do_oop(narrowOop* p) { do_oop_work(p); } |
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2017 void do_oop( oop* p) { do_oop_work(p); } |
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2019 template <class T> void do_oop_work(T* p) { |
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2020 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2021 const char* str = NULL; |
| 2022 const char* str2 = ""; | |
| 2023 | |
| 1388 | 2024 if (obj == NULL) { |
| 2025 str = ""; | |
| 2026 } else if (!_g1h->is_in_g1_reserved(obj)) { | |
| 2027 str = " O"; | |
| 2028 } else { | |
| 342 | 2029 HeapRegion* hr = _g1h->heap_region_containing(obj); |
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2030 guarantee(hr != NULL, "invariant"); |
| 1044 | 2031 bool over_tams = false; |
| 2032 if (_use_prev_marking) { | |
| 2033 over_tams = hr->obj_allocated_since_prev_marking(obj); | |
| 2034 } else { | |
| 2035 over_tams = hr->obj_allocated_since_next_marking(obj); | |
| 2036 } | |
| 1388 | 2037 bool marked = _bitmap->isMarked((HeapWord*) obj); |
| 1044 | 2038 |
| 2039 if (over_tams) { | |
| 1388 | 2040 str = " >"; |
| 2041 if (marked) { | |
| 342 | 2042 str2 = " AND MARKED"; |
| 1044 | 2043 } |
| 1388 | 2044 } else if (marked) { |
| 2045 str = " M"; | |
| 1044 | 2046 } else { |
| 1388 | 2047 str = " NOT"; |
| 1044 | 2048 } |
| 342 | 2049 } |
| 2050 | |
| 1388 | 2051 _out->print_cr(" "PTR_FORMAT": "PTR_FORMAT"%s%s", |
| 342 | 2052 p, (void*) obj, str, str2); |
| 2053 } | |
| 2054 }; | |
| 2055 | |
| 1388 | 2056 class PrintReachableObjectClosure : public ObjectClosure { |
| 342 | 2057 private: |
| 1044 | 2058 CMBitMapRO* _bitmap; |
| 342 | 2059 outputStream* _out; |
| 1044 | 2060 bool _use_prev_marking; |
| 1388 | 2061 bool _all; |
| 2062 HeapRegion* _hr; | |
| 342 | 2063 |
| 2064 public: | |
| 1388 | 2065 PrintReachableObjectClosure(CMBitMapRO* bitmap, |
| 2066 outputStream* out, | |
| 2067 bool use_prev_marking, | |
| 2068 bool all, | |
| 2069 HeapRegion* hr) : | |
| 2070 _bitmap(bitmap), _out(out), | |
| 2071 _use_prev_marking(use_prev_marking), _all(all), _hr(hr) { } | |
| 2072 | |
| 2073 void do_object(oop o) { | |
| 2074 bool over_tams; | |
| 2075 if (_use_prev_marking) { | |
| 2076 over_tams = _hr->obj_allocated_since_prev_marking(o); | |
| 2077 } else { | |
| 2078 over_tams = _hr->obj_allocated_since_next_marking(o); | |
| 2079 } | |
| 2080 bool marked = _bitmap->isMarked((HeapWord*) o); | |
| 2081 bool print_it = _all || over_tams || marked; | |
| 2082 | |
| 2083 if (print_it) { | |
| 2084 _out->print_cr(" "PTR_FORMAT"%s", | |
| 2085 o, (over_tams) ? " >" : (marked) ? " M" : ""); | |
| 2086 PrintReachableOopClosure oopCl(_bitmap, _out, _use_prev_marking, _all); | |
| 2087 o->oop_iterate(&oopCl); | |
| 2088 } | |
| 342 | 2089 } |
| 2090 }; | |
| 2091 | |
| 1388 | 2092 class PrintReachableRegionClosure : public HeapRegionClosure { |
| 342 | 2093 private: |
| 1044 | 2094 CMBitMapRO* _bitmap; |
| 342 | 2095 outputStream* _out; |
| 1044 | 2096 bool _use_prev_marking; |
| 1388 | 2097 bool _all; |
| 342 | 2098 |
| 2099 public: | |
| 2100 bool doHeapRegion(HeapRegion* hr) { | |
| 2101 HeapWord* b = hr->bottom(); | |
| 2102 HeapWord* e = hr->end(); | |
| 2103 HeapWord* t = hr->top(); | |
| 1044 | 2104 HeapWord* p = NULL; |
| 2105 if (_use_prev_marking) { | |
| 2106 p = hr->prev_top_at_mark_start(); | |
| 2107 } else { | |
| 2108 p = hr->next_top_at_mark_start(); | |
| 2109 } | |
| 342 | 2110 _out->print_cr("** ["PTR_FORMAT", "PTR_FORMAT"] top: "PTR_FORMAT" " |
| 1044 | 2111 "TAMS: "PTR_FORMAT, b, e, t, p); |
| 1388 | 2112 _out->cr(); |
| 2113 | |
| 2114 HeapWord* from = b; | |
| 2115 HeapWord* to = t; | |
| 2116 | |
| 2117 if (to > from) { | |
| 2118 _out->print_cr("Objects in ["PTR_FORMAT", "PTR_FORMAT"]", from, to); | |
| 2119 _out->cr(); | |
| 2120 PrintReachableObjectClosure ocl(_bitmap, _out, | |
| 2121 _use_prev_marking, _all, hr); | |
| 2122 hr->object_iterate_mem_careful(MemRegion(from, to), &ocl); | |
| 2123 _out->cr(); | |
| 2124 } | |
| 342 | 2125 |
| 2126 return false; | |
| 2127 } | |
| 2128 | |
| 1388 | 2129 PrintReachableRegionClosure(CMBitMapRO* bitmap, |
| 2130 outputStream* out, | |
| 2131 bool use_prev_marking, | |
| 2132 bool all) : | |
| 2133 _bitmap(bitmap), _out(out), _use_prev_marking(use_prev_marking), _all(all) { } | |
| 342 | 2134 }; |
| 2135 | |
| 1388 | 2136 void ConcurrentMark::print_reachable(const char* str, |
| 2137 bool use_prev_marking, | |
| 2138 bool all) { | |
| 2139 gclog_or_tty->cr(); | |
| 2140 gclog_or_tty->print_cr("== Doing heap dump... "); | |
| 1044 | 2141 |
| 2142 if (G1PrintReachableBaseFile == NULL) { | |
| 2143 gclog_or_tty->print_cr(" #### error: no base file defined"); | |
| 2144 return; | |
| 2145 } | |
| 2146 | |
| 2147 if (strlen(G1PrintReachableBaseFile) + 1 + strlen(str) > | |
| 2148 (JVM_MAXPATHLEN - 1)) { | |
| 2149 gclog_or_tty->print_cr(" #### error: file name too long"); | |
| 2150 return; | |
| 2151 } | |
| 2152 | |
| 2153 char file_name[JVM_MAXPATHLEN]; | |
| 2154 sprintf(file_name, "%s.%s", G1PrintReachableBaseFile, str); | |
| 2155 gclog_or_tty->print_cr(" dumping to file %s", file_name); | |
| 2156 | |
| 2157 fileStream fout(file_name); | |
| 2158 if (!fout.is_open()) { | |
| 2159 gclog_or_tty->print_cr(" #### error: could not open file"); | |
| 2160 return; | |
| 2161 } | |
| 2162 | |
| 2163 outputStream* out = &fout; | |
| 2164 | |
| 2165 CMBitMapRO* bitmap = NULL; | |
| 2166 if (use_prev_marking) { | |
| 2167 bitmap = _prevMarkBitMap; | |
| 2168 } else { | |
| 2169 bitmap = _nextMarkBitMap; | |
| 2170 } | |
| 2171 | |
| 2172 out->print_cr("-- USING %s", (use_prev_marking) ? "PTAMS" : "NTAMS"); | |
| 2173 out->cr(); | |
| 2174 | |
| 1388 | 2175 out->print_cr("--- ITERATING OVER REGIONS"); |
| 1044 | 2176 out->cr(); |
| 1388 | 2177 PrintReachableRegionClosure rcl(bitmap, out, use_prev_marking, all); |
| 2178 _g1h->heap_region_iterate(&rcl); | |
| 1044 | 2179 out->cr(); |
| 2180 | |
| 2181 gclog_or_tty->print_cr(" done"); | |
| 1388 | 2182 gclog_or_tty->flush(); |
| 342 | 2183 } |
| 2184 | |
| 1044 | 2185 #endif // PRODUCT |
| 2186 | |
| 342 | 2187 // This note is for drainAllSATBBuffers and the code in between. |
| 2188 // In the future we could reuse a task to do this work during an | |
| 2189 // evacuation pause (since now tasks are not active and can be claimed | |
| 2190 // during an evacuation pause). This was a late change to the code and | |
| 2191 // is currently not being taken advantage of. | |
| 2192 | |
| 2193 class CMGlobalObjectClosure : public ObjectClosure { | |
| 2194 private: | |
| 2195 ConcurrentMark* _cm; | |
| 2196 | |
| 2197 public: | |
| 2198 void do_object(oop obj) { | |
| 2199 _cm->deal_with_reference(obj); | |
| 2200 } | |
| 2201 | |
| 2202 CMGlobalObjectClosure(ConcurrentMark* cm) : _cm(cm) { } | |
| 2203 }; | |
| 2204 | |
| 2205 void ConcurrentMark::deal_with_reference(oop obj) { | |
| 2206 if (verbose_high()) | |
| 2207 gclog_or_tty->print_cr("[global] we're dealing with reference "PTR_FORMAT, | |
| 2208 (void*) obj); | |
| 2209 | |
| 2210 | |
| 2211 HeapWord* objAddr = (HeapWord*) obj; | |
|
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2212 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 2213 if (_g1h->is_in_g1_reserved(objAddr)) { |
|
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2214 assert(obj != NULL, "is_in_g1_reserved should ensure this"); |
| 342 | 2215 HeapRegion* hr = _g1h->heap_region_containing(obj); |
| 2216 if (_g1h->is_obj_ill(obj, hr)) { | |
| 2217 if (verbose_high()) | |
| 2218 gclog_or_tty->print_cr("[global] "PTR_FORMAT" is not considered " | |
| 2219 "marked", (void*) obj); | |
| 2220 | |
| 2221 // we need to mark it first | |
| 2222 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 2223 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 2224 // CAS done in parMark(objAddr) above | |
| 2225 HeapWord* finger = _finger; | |
| 2226 if (objAddr < finger) { | |
| 2227 if (verbose_high()) | |
| 2228 gclog_or_tty->print_cr("[global] below the global finger " | |
| 2229 "("PTR_FORMAT"), pushing it", finger); | |
| 2230 if (!mark_stack_push(obj)) { | |
| 2231 if (verbose_low()) | |
| 2232 gclog_or_tty->print_cr("[global] global stack overflow during " | |
| 2233 "deal_with_reference"); | |
| 2234 } | |
| 2235 } | |
| 2236 } | |
| 2237 } | |
| 2238 } | |
| 2239 } | |
| 2240 | |
| 2241 void ConcurrentMark::drainAllSATBBuffers() { | |
| 2242 CMGlobalObjectClosure oc(this); | |
| 2243 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2244 satb_mq_set.set_closure(&oc); | |
| 2245 | |
| 2246 while (satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 2247 if (verbose_medium()) | |
| 2248 gclog_or_tty->print_cr("[global] processed an SATB buffer"); | |
| 2249 } | |
| 2250 | |
| 2251 // no need to check whether we should do this, as this is only | |
| 2252 // called during an evacuation pause | |
| 2253 satb_mq_set.iterate_closure_all_threads(); | |
| 2254 | |
| 2255 satb_mq_set.set_closure(NULL); | |
|
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|
2256 assert(satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 2257 } |
| 2258 | |
| 2259 void ConcurrentMark::markPrev(oop p) { | |
| 2260 // Note we are overriding the read-only view of the prev map here, via | |
| 2261 // the cast. | |
| 2262 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*)p); | |
| 2263 } | |
| 2264 | |
| 2265 void ConcurrentMark::clear(oop p) { | |
| 2266 assert(p != NULL && p->is_oop(), "expected an oop"); | |
| 2267 HeapWord* addr = (HeapWord*)p; | |
| 2268 assert(addr >= _nextMarkBitMap->startWord() || | |
| 2269 addr < _nextMarkBitMap->endWord(), "in a region"); | |
| 2270 | |
| 2271 _nextMarkBitMap->clear(addr); | |
| 2272 } | |
| 2273 | |
| 2274 void ConcurrentMark::clearRangeBothMaps(MemRegion mr) { | |
| 2275 // Note we are overriding the read-only view of the prev map here, via | |
| 2276 // the cast. | |
| 2277 ((CMBitMap*)_prevMarkBitMap)->clearRange(mr); | |
| 2278 _nextMarkBitMap->clearRange(mr); | |
| 2279 } | |
| 2280 | |
| 2281 HeapRegion* | |
| 2282 ConcurrentMark::claim_region(int task_num) { | |
| 2283 // "checkpoint" the finger | |
| 2284 HeapWord* finger = _finger; | |
| 2285 | |
| 2286 // _heap_end will not change underneath our feet; it only changes at | |
| 2287 // yield points. | |
| 2288 while (finger < _heap_end) { | |
|
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2289 assert(_g1h->is_in_g1_reserved(finger), "invariant"); |
| 342 | 2290 |
| 2291 // is the gap between reading the finger and doing the CAS too long? | |
| 2292 | |
| 2293 HeapRegion* curr_region = _g1h->heap_region_containing(finger); | |
| 2294 HeapWord* bottom = curr_region->bottom(); | |
| 2295 HeapWord* end = curr_region->end(); | |
| 2296 HeapWord* limit = curr_region->next_top_at_mark_start(); | |
| 2297 | |
| 2298 if (verbose_low()) | |
| 2299 gclog_or_tty->print_cr("[%d] curr_region = "PTR_FORMAT" " | |
| 2300 "["PTR_FORMAT", "PTR_FORMAT"), " | |
| 2301 "limit = "PTR_FORMAT, | |
| 2302 task_num, curr_region, bottom, end, limit); | |
| 2303 | |
| 2304 HeapWord* res = | |
| 2305 (HeapWord*) Atomic::cmpxchg_ptr(end, &_finger, finger); | |
| 2306 if (res == finger) { | |
| 2307 // we succeeded | |
| 2308 | |
| 2309 // notice that _finger == end cannot be guaranteed here since, | |
| 2310 // someone else might have moved the finger even further | |
|
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2311 assert(_finger >= end, "the finger should have moved forward"); |
| 342 | 2312 |
| 2313 if (verbose_low()) | |
| 2314 gclog_or_tty->print_cr("[%d] we were successful with region = " | |
| 2315 PTR_FORMAT, task_num, curr_region); | |
| 2316 | |
| 2317 if (limit > bottom) { | |
| 2318 if (verbose_low()) | |
| 2319 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is not empty, " | |
| 2320 "returning it ", task_num, curr_region); | |
| 2321 return curr_region; | |
| 2322 } else { | |
|
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2323 assert(limit == bottom, |
|
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|
2324 "the region limit should be at bottom"); |
| 342 | 2325 if (verbose_low()) |
| 2326 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is empty, " | |
| 2327 "returning NULL", task_num, curr_region); | |
| 2328 // we return NULL and the caller should try calling | |
| 2329 // claim_region() again. | |
| 2330 return NULL; | |
| 2331 } | |
| 2332 } else { | |
|
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|
2333 assert(_finger > finger, "the finger should have moved forward"); |
| 342 | 2334 if (verbose_low()) |
| 2335 gclog_or_tty->print_cr("[%d] somebody else moved the finger, " | |
| 2336 "global finger = "PTR_FORMAT", " | |
| 2337 "our finger = "PTR_FORMAT, | |
| 2338 task_num, _finger, finger); | |
| 2339 | |
| 2340 // read it again | |
| 2341 finger = _finger; | |
| 2342 } | |
| 2343 } | |
| 2344 | |
| 2345 return NULL; | |
| 2346 } | |
| 2347 | |
|
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2348 bool ConcurrentMark::invalidate_aborted_regions_in_cset() { |
|
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2349 bool result = false; |
|
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2350 for (int i = 0; i < (int)_max_task_num; ++i) { |
|
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2351 CMTask* the_task = _tasks[i]; |
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2352 MemRegion mr = the_task->aborted_region(); |
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2353 if (mr.start() != NULL) { |
|
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2354 assert(mr.end() != NULL, "invariant"); |
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2355 assert(mr.word_size() > 0, "invariant"); |
|
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2356 HeapRegion* hr = _g1h->heap_region_containing(mr.start()); |
|
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2357 assert(hr != NULL, "invariant"); |
|
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2358 if (hr->in_collection_set()) { |
|
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2359 // The region points into the collection set |
|
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2360 the_task->set_aborted_region(MemRegion()); |
|
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2361 result = true; |
|
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|
2362 } |
|
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|
2363 } |
|
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|
2364 } |
|
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2365 return result; |
|
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|
2366 } |
|
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|
2367 |
|
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|
2368 bool ConcurrentMark::has_aborted_regions() { |
|
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2369 for (int i = 0; i < (int)_max_task_num; ++i) { |
|
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2370 CMTask* the_task = _tasks[i]; |
|
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2371 MemRegion mr = the_task->aborted_region(); |
|
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2372 if (mr.start() != NULL) { |
|
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2373 assert(mr.end() != NULL, "invariant"); |
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2374 assert(mr.word_size() > 0, "invariant"); |
|
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2375 return true; |
|
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|
2376 } |
|
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|
2377 } |
|
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|
2378 return false; |
|
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|
2379 } |
|
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|
2380 |
| 342 | 2381 void ConcurrentMark::oops_do(OopClosure* cl) { |
| 2382 if (_markStack.size() > 0 && verbose_low()) | |
| 2383 gclog_or_tty->print_cr("[global] scanning the global marking stack, " | |
| 2384 "size = %d", _markStack.size()); | |
| 2385 // we first iterate over the contents of the mark stack... | |
| 2386 _markStack.oops_do(cl); | |
| 2387 | |
| 2388 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2389 OopTaskQueue* queue = _task_queues->queue((int)i); | |
| 2390 | |
| 2391 if (queue->size() > 0 && verbose_low()) | |
| 2392 gclog_or_tty->print_cr("[global] scanning task queue of task %d, " | |
| 2393 "size = %d", i, queue->size()); | |
| 2394 | |
| 2395 // ...then over the contents of the all the task queues. | |
| 2396 queue->oops_do(cl); | |
| 2397 } | |
| 2398 | |
|
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|
2399 // Invalidate any entries, that are in the region stack, that |
| 342 | 2400 // point into the collection set |
| 2401 if (_regionStack.invalidate_entries_into_cset()) { | |
| 2402 // otherwise, any gray objects copied during the evacuation pause | |
| 2403 // might not be visited. | |
|
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2404 assert(_should_gray_objects, "invariant"); |
| 342 | 2405 } |
|
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2406 |
|
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|
2407 // Invalidate any aborted regions, recorded in the individual CM |
|
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2408 // tasks, that point into the collection set. |
|
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|
2409 if (invalidate_aborted_regions_in_cset()) { |
|
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|
2410 // otherwise, any gray objects copied during the evacuation pause |
|
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|
2411 // might not be visited. |
|
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|
2412 assert(_should_gray_objects, "invariant"); |
|
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2413 } |
|
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|
2414 |
| 342 | 2415 } |
| 2416 | |
| 2417 void ConcurrentMark::clear_marking_state() { | |
| 2418 _markStack.setEmpty(); | |
| 2419 _markStack.clear_overflow(); | |
| 2420 _regionStack.setEmpty(); | |
| 2421 _regionStack.clear_overflow(); | |
| 2422 clear_has_overflown(); | |
| 2423 _finger = _heap_start; | |
| 2424 | |
| 2425 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2426 OopTaskQueue* queue = _task_queues->queue(i); | |
| 2427 queue->set_empty(); | |
|
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|
2428 // Clear any partial regions from the CMTasks |
|
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|
2429 _tasks[i]->clear_aborted_region(); |
| 342 | 2430 } |
| 2431 } | |
| 2432 | |
| 2433 void ConcurrentMark::print_stats() { | |
| 2434 if (verbose_stats()) { | |
| 2435 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2436 for (size_t i = 0; i < _active_tasks; ++i) { | |
| 2437 _tasks[i]->print_stats(); | |
| 2438 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2439 } | |
| 2440 } | |
| 2441 } | |
| 2442 | |
| 2443 class CSMarkOopClosure: public OopClosure { | |
| 2444 friend class CSMarkBitMapClosure; | |
| 2445 | |
| 2446 G1CollectedHeap* _g1h; | |
| 2447 CMBitMap* _bm; | |
| 2448 ConcurrentMark* _cm; | |
| 2449 oop* _ms; | |
| 2450 jint* _array_ind_stack; | |
| 2451 int _ms_size; | |
| 2452 int _ms_ind; | |
| 2453 int _array_increment; | |
| 2454 | |
| 2455 bool push(oop obj, int arr_ind = 0) { | |
| 2456 if (_ms_ind == _ms_size) { | |
| 2457 gclog_or_tty->print_cr("Mark stack is full."); | |
| 2458 return false; | |
| 2459 } | |
| 2460 _ms[_ms_ind] = obj; | |
| 2461 if (obj->is_objArray()) _array_ind_stack[_ms_ind] = arr_ind; | |
| 2462 _ms_ind++; | |
| 2463 return true; | |
| 2464 } | |
| 2465 | |
| 2466 oop pop() { | |
| 2467 if (_ms_ind == 0) return NULL; | |
| 2468 else { | |
| 2469 _ms_ind--; | |
| 2470 return _ms[_ms_ind]; | |
| 2471 } | |
| 2472 } | |
| 2473 | |
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2474 template <class T> bool drain() { |
| 342 | 2475 while (_ms_ind > 0) { |
| 2476 oop obj = pop(); | |
| 2477 assert(obj != NULL, "Since index was non-zero."); | |
| 2478 if (obj->is_objArray()) { | |
| 2479 jint arr_ind = _array_ind_stack[_ms_ind]; | |
| 2480 objArrayOop aobj = objArrayOop(obj); | |
| 2481 jint len = aobj->length(); | |
| 2482 jint next_arr_ind = arr_ind + _array_increment; | |
| 2483 if (next_arr_ind < len) { | |
| 2484 push(obj, next_arr_ind); | |
| 2485 } | |
| 2486 // Now process this portion of this one. | |
| 2487 int lim = MIN2(next_arr_ind, len); | |
| 2488 for (int j = arr_ind; j < lim; j++) { | |
|
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2489 do_oop(aobj->objArrayOopDesc::obj_at_addr<T>(j)); |
| 342 | 2490 } |
| 2491 | |
| 2492 } else { | |
| 2493 obj->oop_iterate(this); | |
| 2494 } | |
| 2495 if (abort()) return false; | |
| 2496 } | |
| 2497 return true; | |
| 2498 } | |
| 2499 | |
| 2500 public: | |
| 2501 CSMarkOopClosure(ConcurrentMark* cm, int ms_size) : | |
| 2502 _g1h(G1CollectedHeap::heap()), | |
| 2503 _cm(cm), | |
| 2504 _bm(cm->nextMarkBitMap()), | |
| 2505 _ms_size(ms_size), _ms_ind(0), | |
| 2506 _ms(NEW_C_HEAP_ARRAY(oop, ms_size)), | |
| 2507 _array_ind_stack(NEW_C_HEAP_ARRAY(jint, ms_size)), | |
| 2508 _array_increment(MAX2(ms_size/8, 16)) | |
| 2509 {} | |
| 2510 | |
| 2511 ~CSMarkOopClosure() { | |
| 2512 FREE_C_HEAP_ARRAY(oop, _ms); | |
| 2513 FREE_C_HEAP_ARRAY(jint, _array_ind_stack); | |
| 2514 } | |
| 2515 | |
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2516 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2517 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2518 |
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2519 template <class T> void do_oop_work(T* p) { |
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2520 T heap_oop = oopDesc::load_heap_oop(p); |
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2521 if (oopDesc::is_null(heap_oop)) return; |
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2522 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
| 342 | 2523 if (obj->is_forwarded()) { |
| 2524 // If the object has already been forwarded, we have to make sure | |
| 2525 // that it's marked. So follow the forwarding pointer. Note that | |
| 2526 // this does the right thing for self-forwarding pointers in the | |
| 2527 // evacuation failure case. | |
| 2528 obj = obj->forwardee(); | |
| 2529 } | |
| 2530 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2531 if (hr != NULL) { | |
| 2532 if (hr->in_collection_set()) { | |
| 2533 if (_g1h->is_obj_ill(obj)) { | |
| 2534 _bm->mark((HeapWord*)obj); | |
| 2535 if (!push(obj)) { | |
| 2536 gclog_or_tty->print_cr("Setting abort in CSMarkOopClosure because push failed."); | |
| 2537 set_abort(); | |
| 2538 } | |
| 2539 } | |
| 2540 } else { | |
| 2541 // Outside the collection set; we need to gray it | |
| 2542 _cm->deal_with_reference(obj); | |
| 2543 } | |
| 2544 } | |
| 2545 } | |
| 2546 }; | |
| 2547 | |
| 2548 class CSMarkBitMapClosure: public BitMapClosure { | |
| 2549 G1CollectedHeap* _g1h; | |
| 2550 CMBitMap* _bitMap; | |
| 2551 ConcurrentMark* _cm; | |
| 2552 CSMarkOopClosure _oop_cl; | |
| 2553 public: | |
| 2554 CSMarkBitMapClosure(ConcurrentMark* cm, int ms_size) : | |
| 2555 _g1h(G1CollectedHeap::heap()), | |
| 2556 _bitMap(cm->nextMarkBitMap()), | |
| 2557 _oop_cl(cm, ms_size) | |
| 2558 {} | |
| 2559 | |
| 2560 ~CSMarkBitMapClosure() {} | |
| 2561 | |
| 2562 bool do_bit(size_t offset) { | |
| 2563 // convert offset into a HeapWord* | |
| 2564 HeapWord* addr = _bitMap->offsetToHeapWord(offset); | |
| 2565 assert(_bitMap->endWord() && addr < _bitMap->endWord(), | |
| 2566 "address out of range"); | |
| 2567 assert(_bitMap->isMarked(addr), "tautology"); | |
| 2568 oop obj = oop(addr); | |
| 2569 if (!obj->is_forwarded()) { | |
| 2570 if (!_oop_cl.push(obj)) return false; | |
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2571 if (UseCompressedOops) { |
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2572 if (!_oop_cl.drain<narrowOop>()) return false; |
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2573 } else { |
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2574 if (!_oop_cl.drain<oop>()) return false; |
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2575 } |
| 342 | 2576 } |
| 2577 // Otherwise... | |
| 2578 return true; | |
| 2579 } | |
| 2580 }; | |
| 2581 | |
| 2582 | |
| 2583 class CompleteMarkingInCSHRClosure: public HeapRegionClosure { | |
| 2584 CMBitMap* _bm; | |
| 2585 CSMarkBitMapClosure _bit_cl; | |
| 2586 enum SomePrivateConstants { | |
| 2587 MSSize = 1000 | |
| 2588 }; | |
| 2589 bool _completed; | |
| 2590 public: | |
| 2591 CompleteMarkingInCSHRClosure(ConcurrentMark* cm) : | |
| 2592 _bm(cm->nextMarkBitMap()), | |
| 2593 _bit_cl(cm, MSSize), | |
| 2594 _completed(true) | |
| 2595 {} | |
| 2596 | |
| 2597 ~CompleteMarkingInCSHRClosure() {} | |
| 2598 | |
| 2599 bool doHeapRegion(HeapRegion* r) { | |
| 2600 if (!r->evacuation_failed()) { | |
| 2601 MemRegion mr = MemRegion(r->bottom(), r->next_top_at_mark_start()); | |
| 2602 if (!mr.is_empty()) { | |
| 2603 if (!_bm->iterate(&_bit_cl, mr)) { | |
| 2604 _completed = false; | |
| 2605 return true; | |
| 2606 } | |
| 2607 } | |
| 2608 } | |
| 2609 return false; | |
| 2610 } | |
| 2611 | |
| 2612 bool completed() { return _completed; } | |
| 2613 }; | |
| 2614 | |
| 2615 class ClearMarksInHRClosure: public HeapRegionClosure { | |
| 2616 CMBitMap* _bm; | |
| 2617 public: | |
| 2618 ClearMarksInHRClosure(CMBitMap* bm): _bm(bm) { } | |
| 2619 | |
| 2620 bool doHeapRegion(HeapRegion* r) { | |
| 2621 if (!r->used_region().is_empty() && !r->evacuation_failed()) { | |
| 2622 MemRegion usedMR = r->used_region(); | |
| 2623 _bm->clearRange(r->used_region()); | |
| 2624 } | |
| 2625 return false; | |
| 2626 } | |
| 2627 }; | |
| 2628 | |
| 2629 void ConcurrentMark::complete_marking_in_collection_set() { | |
| 2630 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 2631 | |
| 2632 if (!g1h->mark_in_progress()) { | |
| 2633 g1h->g1_policy()->record_mark_closure_time(0.0); | |
| 2634 return; | |
| 2635 } | |
| 2636 | |
| 2637 int i = 1; | |
| 2638 double start = os::elapsedTime(); | |
| 2639 while (true) { | |
| 2640 i++; | |
| 2641 CompleteMarkingInCSHRClosure cmplt(this); | |
| 2642 g1h->collection_set_iterate(&cmplt); | |
| 2643 if (cmplt.completed()) break; | |
| 2644 } | |
| 2645 double end_time = os::elapsedTime(); | |
| 2646 double elapsed_time_ms = (end_time - start) * 1000.0; | |
| 2647 g1h->g1_policy()->record_mark_closure_time(elapsed_time_ms); | |
| 2648 | |
| 2649 ClearMarksInHRClosure clr(nextMarkBitMap()); | |
| 2650 g1h->collection_set_iterate(&clr); | |
| 2651 } | |
| 2652 | |
| 2653 // The next two methods deal with the following optimisation. Some | |
| 2654 // objects are gray by being marked and located above the finger. If | |
| 2655 // they are copied, during an evacuation pause, below the finger then | |
| 2656 // the need to be pushed on the stack. The observation is that, if | |
| 2657 // there are no regions in the collection set located above the | |
| 2658 // finger, then the above cannot happen, hence we do not need to | |
| 2659 // explicitly gray any objects when copying them to below the | |
| 2660 // finger. The global stack will be scanned to ensure that, if it | |
| 2661 // points to objects being copied, it will update their | |
| 2662 // location. There is a tricky situation with the gray objects in | |
| 2663 // region stack that are being coped, however. See the comment in | |
| 2664 // newCSet(). | |
| 2665 | |
| 2666 void ConcurrentMark::newCSet() { | |
| 2667 if (!concurrent_marking_in_progress()) | |
| 2668 // nothing to do if marking is not in progress | |
| 2669 return; | |
| 2670 | |
| 2671 // find what the lowest finger is among the global and local fingers | |
| 2672 _min_finger = _finger; | |
| 2673 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2674 CMTask* task = _tasks[i]; | |
| 2675 HeapWord* task_finger = task->finger(); | |
| 2676 if (task_finger != NULL && task_finger < _min_finger) | |
| 2677 _min_finger = task_finger; | |
| 2678 } | |
| 2679 | |
| 2680 _should_gray_objects = false; | |
| 2681 | |
| 2682 // This fixes a very subtle and fustrating bug. It might be the case | |
| 2683 // that, during en evacuation pause, heap regions that contain | |
| 2684 // objects that are gray (by being in regions contained in the | |
| 2685 // region stack) are included in the collection set. Since such gray | |
| 2686 // objects will be moved, and because it's not easy to redirect | |
| 2687 // region stack entries to point to a new location (because objects | |
| 2688 // in one region might be scattered to multiple regions after they | |
| 2689 // are copied), one option is to ensure that all marked objects | |
| 2690 // copied during a pause are pushed on the stack. Notice, however, | |
| 2691 // that this problem can only happen when the region stack is not | |
| 2692 // empty during an evacuation pause. So, we make the fix a bit less | |
| 2693 // conservative and ensure that regions are pushed on the stack, | |
| 2694 // irrespective whether all collection set regions are below the | |
| 2695 // finger, if the region stack is not empty. This is expected to be | |
| 2696 // a rare case, so I don't think it's necessary to be smarted about it. | |
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2697 if (!region_stack_empty() || has_aborted_regions()) |
| 342 | 2698 _should_gray_objects = true; |
| 2699 } | |
| 2700 | |
| 2701 void ConcurrentMark::registerCSetRegion(HeapRegion* hr) { | |
| 2702 if (!concurrent_marking_in_progress()) | |
| 2703 return; | |
| 2704 | |
| 2705 HeapWord* region_end = hr->end(); | |
| 2706 if (region_end > _min_finger) | |
| 2707 _should_gray_objects = true; | |
| 2708 } | |
| 2709 | |
| 2710 // abandon current marking iteration due to a Full GC | |
| 2711 void ConcurrentMark::abort() { | |
| 2712 // Clear all marks to force marking thread to do nothing | |
| 2713 _nextMarkBitMap->clearAll(); | |
| 2714 // Empty mark stack | |
| 2715 clear_marking_state(); | |
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2716 for (int i = 0; i < (int)_max_task_num; ++i) { |
| 342 | 2717 _tasks[i]->clear_region_fields(); |
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2718 } |
| 342 | 2719 _has_aborted = true; |
| 2720 | |
| 2721 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2722 satb_mq_set.abandon_partial_marking(); | |
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2723 // This can be called either during or outside marking, we'll read |
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2724 // the expected_active value from the SATB queue set. |
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2725 satb_mq_set.set_active_all_threads( |
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2726 false, /* new active value */ |
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2727 satb_mq_set.is_active() /* expected_active */); |
| 342 | 2728 } |
| 2729 | |
| 2730 static void print_ms_time_info(const char* prefix, const char* name, | |
| 2731 NumberSeq& ns) { | |
| 2732 gclog_or_tty->print_cr("%s%5d %12s: total time = %8.2f s (avg = %8.2f ms).", | |
| 2733 prefix, ns.num(), name, ns.sum()/1000.0, ns.avg()); | |
| 2734 if (ns.num() > 0) { | |
| 2735 gclog_or_tty->print_cr("%s [std. dev = %8.2f ms, max = %8.2f ms]", | |
| 2736 prefix, ns.sd(), ns.maximum()); | |
| 2737 } | |
| 2738 } | |
| 2739 | |
| 2740 void ConcurrentMark::print_summary_info() { | |
| 2741 gclog_or_tty->print_cr(" Concurrent marking:"); | |
| 2742 print_ms_time_info(" ", "init marks", _init_times); | |
| 2743 print_ms_time_info(" ", "remarks", _remark_times); | |
| 2744 { | |
| 2745 print_ms_time_info(" ", "final marks", _remark_mark_times); | |
| 2746 print_ms_time_info(" ", "weak refs", _remark_weak_ref_times); | |
| 2747 | |
| 2748 } | |
| 2749 print_ms_time_info(" ", "cleanups", _cleanup_times); | |
| 2750 gclog_or_tty->print_cr(" Final counting total time = %8.2f s (avg = %8.2f ms).", | |
| 2751 _total_counting_time, | |
| 2752 (_cleanup_times.num() > 0 ? _total_counting_time * 1000.0 / | |
| 2753 (double)_cleanup_times.num() | |
| 2754 : 0.0)); | |
| 2755 if (G1ScrubRemSets) { | |
| 2756 gclog_or_tty->print_cr(" RS scrub total time = %8.2f s (avg = %8.2f ms).", | |
| 2757 _total_rs_scrub_time, | |
| 2758 (_cleanup_times.num() > 0 ? _total_rs_scrub_time * 1000.0 / | |
| 2759 (double)_cleanup_times.num() | |
| 2760 : 0.0)); | |
| 2761 } | |
| 2762 gclog_or_tty->print_cr(" Total stop_world time = %8.2f s.", | |
| 2763 (_init_times.sum() + _remark_times.sum() + | |
| 2764 _cleanup_times.sum())/1000.0); | |
| 2765 gclog_or_tty->print_cr(" Total concurrent time = %8.2f s " | |
| 2766 "(%8.2f s marking, %8.2f s counting).", | |
| 2767 cmThread()->vtime_accum(), | |
| 2768 cmThread()->vtime_mark_accum(), | |
| 2769 cmThread()->vtime_count_accum()); | |
| 2770 } | |
| 2771 | |
| 1019 | 2772 void ConcurrentMark::print_worker_threads_on(outputStream* st) const { |
| 2773 _parallel_workers->print_worker_threads_on(st); | |
| 2774 } | |
| 2775 | |
| 342 | 2776 // Closures |
| 2777 // XXX: there seems to be a lot of code duplication here; | |
| 2778 // should refactor and consolidate the shared code. | |
| 2779 | |
| 2780 // This closure is used to mark refs into the CMS generation in | |
| 2781 // the CMS bit map. Called at the first checkpoint. | |
| 2782 | |
| 2783 // We take a break if someone is trying to stop the world. | |
| 2784 bool ConcurrentMark::do_yield_check(int worker_i) { | |
| 2785 if (should_yield()) { | |
| 2786 if (worker_i == 0) | |
| 2787 _g1h->g1_policy()->record_concurrent_pause(); | |
| 2788 cmThread()->yield(); | |
| 2789 if (worker_i == 0) | |
| 2790 _g1h->g1_policy()->record_concurrent_pause_end(); | |
| 2791 return true; | |
| 2792 } else { | |
| 2793 return false; | |
| 2794 } | |
| 2795 } | |
| 2796 | |
| 2797 bool ConcurrentMark::should_yield() { | |
| 2798 return cmThread()->should_yield(); | |
| 2799 } | |
| 2800 | |
| 2801 bool ConcurrentMark::containing_card_is_marked(void* p) { | |
| 2802 size_t offset = pointer_delta(p, _g1h->reserved_region().start(), 1); | |
| 2803 return _card_bm.at(offset >> CardTableModRefBS::card_shift); | |
| 2804 } | |
| 2805 | |
| 2806 bool ConcurrentMark::containing_cards_are_marked(void* start, | |
| 2807 void* last) { | |
| 2808 return | |
| 2809 containing_card_is_marked(start) && | |
| 2810 containing_card_is_marked(last); | |
| 2811 } | |
| 2812 | |
| 2813 #ifndef PRODUCT | |
| 2814 // for debugging purposes | |
| 2815 void ConcurrentMark::print_finger() { | |
| 2816 gclog_or_tty->print_cr("heap ["PTR_FORMAT", "PTR_FORMAT"), global finger = "PTR_FORMAT, | |
| 2817 _heap_start, _heap_end, _finger); | |
| 2818 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 2819 gclog_or_tty->print(" %d: "PTR_FORMAT, i, _tasks[i]->finger()); | |
| 2820 } | |
| 2821 gclog_or_tty->print_cr(""); | |
| 2822 } | |
| 2823 #endif | |
| 2824 | |
| 2825 // Closure for iteration over bitmaps | |
| 2826 class CMBitMapClosure : public BitMapClosure { | |
| 2827 private: | |
| 2828 // the bitmap that is being iterated over | |
| 2829 CMBitMap* _nextMarkBitMap; | |
| 2830 ConcurrentMark* _cm; | |
| 2831 CMTask* _task; | |
| 2832 // true if we're scanning a heap region claimed by the task (so that | |
| 2833 // we move the finger along), false if we're not, i.e. currently when | |
| 2834 // scanning a heap region popped from the region stack (so that we | |
| 2835 // do not move the task finger along; it'd be a mistake if we did so). | |
| 2836 bool _scanning_heap_region; | |
| 2837 | |
| 2838 public: | |
| 2839 CMBitMapClosure(CMTask *task, | |
| 2840 ConcurrentMark* cm, | |
| 2841 CMBitMap* nextMarkBitMap) | |
| 2842 : _task(task), _cm(cm), _nextMarkBitMap(nextMarkBitMap) { } | |
| 2843 | |
| 2844 void set_scanning_heap_region(bool scanning_heap_region) { | |
| 2845 _scanning_heap_region = scanning_heap_region; | |
| 2846 } | |
| 2847 | |
| 2848 bool do_bit(size_t offset) { | |
| 2849 HeapWord* addr = _nextMarkBitMap->offsetToHeapWord(offset); | |
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2850 assert(_nextMarkBitMap->isMarked(addr), "invariant"); |
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2851 assert( addr < _cm->finger(), "invariant"); |
| 342 | 2852 |
| 2853 if (_scanning_heap_region) { | |
| 2854 statsOnly( _task->increase_objs_found_on_bitmap() ); | |
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2855 assert(addr >= _task->finger(), "invariant"); |
| 342 | 2856 // We move that task's local finger along. |
| 2857 _task->move_finger_to(addr); | |
| 2858 } else { | |
| 2859 // We move the task's region finger along. | |
| 2860 _task->move_region_finger_to(addr); | |
| 2861 } | |
| 2862 | |
| 2863 _task->scan_object(oop(addr)); | |
| 2864 // we only partially drain the local queue and global stack | |
| 2865 _task->drain_local_queue(true); | |
| 2866 _task->drain_global_stack(true); | |
| 2867 | |
| 2868 // if the has_aborted flag has been raised, we need to bail out of | |
| 2869 // the iteration | |
| 2870 return !_task->has_aborted(); | |
| 2871 } | |
| 2872 }; | |
| 2873 | |
| 2874 // Closure for iterating over objects, currently only used for | |
| 2875 // processing SATB buffers. | |
| 2876 class CMObjectClosure : public ObjectClosure { | |
| 2877 private: | |
| 2878 CMTask* _task; | |
| 2879 | |
| 2880 public: | |
| 2881 void do_object(oop obj) { | |
| 2882 _task->deal_with_reference(obj); | |
| 2883 } | |
| 2884 | |
| 2885 CMObjectClosure(CMTask* task) : _task(task) { } | |
| 2886 }; | |
| 2887 | |
| 2888 // Closure for iterating over object fields | |
| 2889 class CMOopClosure : public OopClosure { | |
| 2890 private: | |
| 2891 G1CollectedHeap* _g1h; | |
| 2892 ConcurrentMark* _cm; | |
| 2893 CMTask* _task; | |
| 2894 | |
| 2895 public: | |
|
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2896 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2897 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2898 |
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2899 template <class T> void do_oop_work(T* p) { |
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2900 assert(_g1h->is_in_g1_reserved((HeapWord*) p), "invariant"); |
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2901 assert(!_g1h->heap_region_containing((HeapWord*) p)->is_on_free_list(), |
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2902 "invariant"); |
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2903 |
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2904 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2905 if (_cm->verbose_high()) |
| 2906 gclog_or_tty->print_cr("[%d] we're looking at location " | |
| 2907 "*"PTR_FORMAT" = "PTR_FORMAT, | |
| 2908 _task->task_id(), p, (void*) obj); | |
| 2909 _task->deal_with_reference(obj); | |
| 2910 } | |
| 2911 | |
| 2912 CMOopClosure(G1CollectedHeap* g1h, | |
| 2913 ConcurrentMark* cm, | |
| 2914 CMTask* task) | |
|
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2915 : _g1h(g1h), _cm(cm), _task(task) |
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2916 { |
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2917 _ref_processor = g1h->ref_processor(); |
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2918 assert(_ref_processor != NULL, "should not be NULL"); |
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2919 } |
| 342 | 2920 }; |
| 2921 | |
| 2922 void CMTask::setup_for_region(HeapRegion* hr) { | |
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2923 // Separated the asserts so that we know which one fires. |
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2924 assert(hr != NULL, |
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2925 "claim_region() should have filtered out continues humongous regions"); |
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2926 assert(!hr->continuesHumongous(), |
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2927 "claim_region() should have filtered out continues humongous regions"); |
| 342 | 2928 |
| 2929 if (_cm->verbose_low()) | |
| 2930 gclog_or_tty->print_cr("[%d] setting up for region "PTR_FORMAT, | |
| 2931 _task_id, hr); | |
| 2932 | |
| 2933 _curr_region = hr; | |
| 2934 _finger = hr->bottom(); | |
| 2935 update_region_limit(); | |
| 2936 } | |
| 2937 | |
| 2938 void CMTask::update_region_limit() { | |
| 2939 HeapRegion* hr = _curr_region; | |
| 2940 HeapWord* bottom = hr->bottom(); | |
| 2941 HeapWord* limit = hr->next_top_at_mark_start(); | |
| 2942 | |
| 2943 if (limit == bottom) { | |
| 2944 if (_cm->verbose_low()) | |
| 2945 gclog_or_tty->print_cr("[%d] found an empty region " | |
| 2946 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 2947 _task_id, bottom, limit); | |
| 2948 // The region was collected underneath our feet. | |
| 2949 // We set the finger to bottom to ensure that the bitmap | |
| 2950 // iteration that will follow this will not do anything. | |
| 2951 // (this is not a condition that holds when we set the region up, | |
| 2952 // as the region is not supposed to be empty in the first place) | |
| 2953 _finger = bottom; | |
| 2954 } else if (limit >= _region_limit) { | |
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2955 assert(limit >= _finger, "peace of mind"); |
| 342 | 2956 } else { |
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2957 assert(limit < _region_limit, "only way to get here"); |
| 342 | 2958 // This can happen under some pretty unusual circumstances. An |
| 2959 // evacuation pause empties the region underneath our feet (NTAMS | |
| 2960 // at bottom). We then do some allocation in the region (NTAMS | |
| 2961 // stays at bottom), followed by the region being used as a GC | |
| 2962 // alloc region (NTAMS will move to top() and the objects | |
| 2963 // originally below it will be grayed). All objects now marked in | |
| 2964 // the region are explicitly grayed, if below the global finger, | |
| 2965 // and we do not need in fact to scan anything else. So, we simply | |
| 2966 // set _finger to be limit to ensure that the bitmap iteration | |
| 2967 // doesn't do anything. | |
| 2968 _finger = limit; | |
| 2969 } | |
| 2970 | |
| 2971 _region_limit = limit; | |
| 2972 } | |
| 2973 | |
| 2974 void CMTask::giveup_current_region() { | |
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2975 assert(_curr_region != NULL, "invariant"); |
| 342 | 2976 if (_cm->verbose_low()) |
| 2977 gclog_or_tty->print_cr("[%d] giving up region "PTR_FORMAT, | |
| 2978 _task_id, _curr_region); | |
| 2979 clear_region_fields(); | |
| 2980 } | |
| 2981 | |
| 2982 void CMTask::clear_region_fields() { | |
| 2983 // Values for these three fields that indicate that we're not | |
| 2984 // holding on to a region. | |
| 2985 _curr_region = NULL; | |
| 2986 _finger = NULL; | |
| 2987 _region_limit = NULL; | |
| 2988 | |
| 2989 _region_finger = NULL; | |
| 2990 } | |
| 2991 | |
| 2992 void CMTask::reset(CMBitMap* nextMarkBitMap) { | |
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2993 guarantee(nextMarkBitMap != NULL, "invariant"); |
| 342 | 2994 |
| 2995 if (_cm->verbose_low()) | |
| 2996 gclog_or_tty->print_cr("[%d] resetting", _task_id); | |
| 2997 | |
| 2998 _nextMarkBitMap = nextMarkBitMap; | |
| 2999 clear_region_fields(); | |
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3000 assert(_aborted_region.is_empty(), "should have been cleared"); |
| 342 | 3001 |
| 3002 _calls = 0; | |
| 3003 _elapsed_time_ms = 0.0; | |
| 3004 _termination_time_ms = 0.0; | |
| 3005 _termination_start_time_ms = 0.0; | |
| 3006 | |
| 3007 #if _MARKING_STATS_ | |
| 3008 _local_pushes = 0; | |
| 3009 _local_pops = 0; | |
| 3010 _local_max_size = 0; | |
| 3011 _objs_scanned = 0; | |
| 3012 _global_pushes = 0; | |
| 3013 _global_pops = 0; | |
| 3014 _global_max_size = 0; | |
| 3015 _global_transfers_to = 0; | |
| 3016 _global_transfers_from = 0; | |
| 3017 _region_stack_pops = 0; | |
| 3018 _regions_claimed = 0; | |
| 3019 _objs_found_on_bitmap = 0; | |
| 3020 _satb_buffers_processed = 0; | |
| 3021 _steal_attempts = 0; | |
| 3022 _steals = 0; | |
| 3023 _aborted = 0; | |
| 3024 _aborted_overflow = 0; | |
| 3025 _aborted_cm_aborted = 0; | |
| 3026 _aborted_yield = 0; | |
| 3027 _aborted_timed_out = 0; | |
| 3028 _aborted_satb = 0; | |
| 3029 _aborted_termination = 0; | |
| 3030 #endif // _MARKING_STATS_ | |
| 3031 } | |
| 3032 | |
| 3033 bool CMTask::should_exit_termination() { | |
| 3034 regular_clock_call(); | |
| 3035 // This is called when we are in the termination protocol. We should | |
| 3036 // quit if, for some reason, this task wants to abort or the global | |
| 3037 // stack is not empty (this means that we can get work from it). | |
| 3038 return !_cm->mark_stack_empty() || has_aborted(); | |
| 3039 } | |
| 3040 | |
| 3041 // This determines whether the method below will check both the local | |
| 3042 // and global fingers when determining whether to push on the stack a | |
| 3043 // gray object (value 1) or whether it will only check the global one | |
| 3044 // (value 0). The tradeoffs are that the former will be a bit more | |
| 3045 // accurate and possibly push less on the stack, but it might also be | |
| 3046 // a little bit slower. | |
| 3047 | |
| 3048 #define _CHECK_BOTH_FINGERS_ 1 | |
| 3049 | |
| 3050 void CMTask::deal_with_reference(oop obj) { | |
| 3051 if (_cm->verbose_high()) | |
| 3052 gclog_or_tty->print_cr("[%d] we're dealing with reference = "PTR_FORMAT, | |
| 3053 _task_id, (void*) obj); | |
| 3054 | |
| 3055 ++_refs_reached; | |
| 3056 | |
| 3057 HeapWord* objAddr = (HeapWord*) obj; | |
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3058 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 3059 if (_g1h->is_in_g1_reserved(objAddr)) { |
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3060 assert(obj != NULL, "is_in_g1_reserved should ensure this"); |
| 342 | 3061 HeapRegion* hr = _g1h->heap_region_containing(obj); |
| 3062 if (_g1h->is_obj_ill(obj, hr)) { | |
| 3063 if (_cm->verbose_high()) | |
| 3064 gclog_or_tty->print_cr("[%d] "PTR_FORMAT" is not considered marked", | |
| 3065 _task_id, (void*) obj); | |
| 3066 | |
| 3067 // we need to mark it first | |
| 3068 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 3069 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 3070 // CAS done in parMark(objAddr) above | |
| 3071 HeapWord* global_finger = _cm->finger(); | |
| 3072 | |
| 3073 #if _CHECK_BOTH_FINGERS_ | |
| 3074 // we will check both the local and global fingers | |
| 3075 | |
| 3076 if (_finger != NULL && objAddr < _finger) { | |
| 3077 if (_cm->verbose_high()) | |
| 3078 gclog_or_tty->print_cr("[%d] below the local finger ("PTR_FORMAT"), " | |
| 3079 "pushing it", _task_id, _finger); | |
| 3080 push(obj); | |
| 3081 } else if (_curr_region != NULL && objAddr < _region_limit) { | |
| 3082 // do nothing | |
| 3083 } else if (objAddr < global_finger) { | |
| 3084 // Notice that the global finger might be moving forward | |
| 3085 // concurrently. This is not a problem. In the worst case, we | |
| 3086 // mark the object while it is above the global finger and, by | |
| 3087 // the time we read the global finger, it has moved forward | |
| 3088 // passed this object. In this case, the object will probably | |
| 3089 // be visited when a task is scanning the region and will also | |
| 3090 // be pushed on the stack. So, some duplicate work, but no | |
| 3091 // correctness problems. | |
| 3092 | |
| 3093 if (_cm->verbose_high()) | |
| 3094 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3095 "("PTR_FORMAT"), pushing it", | |
| 3096 _task_id, global_finger); | |
| 3097 push(obj); | |
| 3098 } else { | |
| 3099 // do nothing | |
| 3100 } | |
| 3101 #else // _CHECK_BOTH_FINGERS_ | |
| 3102 // we will only check the global finger | |
| 3103 | |
| 3104 if (objAddr < global_finger) { | |
| 3105 // see long comment above | |
| 3106 | |
| 3107 if (_cm->verbose_high()) | |
| 3108 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3109 "("PTR_FORMAT"), pushing it", | |
| 3110 _task_id, global_finger); | |
| 3111 push(obj); | |
| 3112 } | |
| 3113 #endif // _CHECK_BOTH_FINGERS_ | |
| 3114 } | |
| 3115 } | |
| 3116 } | |
| 3117 } | |
| 3118 | |
| 3119 void CMTask::push(oop obj) { | |
| 3120 HeapWord* objAddr = (HeapWord*) obj; | |
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3121 assert(_g1h->is_in_g1_reserved(objAddr), "invariant"); |
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3122 assert(!_g1h->heap_region_containing(objAddr)->is_on_free_list(), |
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3123 "invariant"); |
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3124 assert(!_g1h->is_obj_ill(obj), "invariant"); |
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3125 assert(_nextMarkBitMap->isMarked(objAddr), "invariant"); |
| 342 | 3126 |
| 3127 if (_cm->verbose_high()) | |
| 3128 gclog_or_tty->print_cr("[%d] pushing "PTR_FORMAT, _task_id, (void*) obj); | |
| 3129 | |
| 3130 if (!_task_queue->push(obj)) { | |
| 3131 // The local task queue looks full. We need to push some entries | |
| 3132 // to the global stack. | |
| 3133 | |
| 3134 if (_cm->verbose_medium()) | |
| 3135 gclog_or_tty->print_cr("[%d] task queue overflow, " | |
| 3136 "moving entries to the global stack", | |
| 3137 _task_id); | |
| 3138 move_entries_to_global_stack(); | |
| 3139 | |
| 3140 // this should succeed since, even if we overflow the global | |
| 3141 // stack, we should have definitely removed some entries from the | |
| 3142 // local queue. So, there must be space on it. | |
| 3143 bool success = _task_queue->push(obj); | |
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3144 assert(success, "invariant"); |
| 342 | 3145 } |
| 3146 | |
| 3147 statsOnly( int tmp_size = _task_queue->size(); | |
| 3148 if (tmp_size > _local_max_size) | |
| 3149 _local_max_size = tmp_size; | |
| 3150 ++_local_pushes ); | |
| 3151 } | |
| 3152 | |
| 3153 void CMTask::reached_limit() { | |
|
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3154 assert(_words_scanned >= _words_scanned_limit || |
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3155 _refs_reached >= _refs_reached_limit , |
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3156 "shouldn't have been called otherwise"); |
| 342 | 3157 regular_clock_call(); |
| 3158 } | |
| 3159 | |
| 3160 void CMTask::regular_clock_call() { | |
| 3161 if (has_aborted()) | |
| 3162 return; | |
| 3163 | |
| 3164 // First, we need to recalculate the words scanned and refs reached | |
| 3165 // limits for the next clock call. | |
| 3166 recalculate_limits(); | |
| 3167 | |
| 3168 // During the regular clock call we do the following | |
| 3169 | |
| 3170 // (1) If an overflow has been flagged, then we abort. | |
| 3171 if (_cm->has_overflown()) { | |
| 3172 set_has_aborted(); | |
| 3173 return; | |
| 3174 } | |
| 3175 | |
| 3176 // If we are not concurrent (i.e. we're doing remark) we don't need | |
| 3177 // to check anything else. The other steps are only needed during | |
| 3178 // the concurrent marking phase. | |
| 3179 if (!concurrent()) | |
| 3180 return; | |
| 3181 | |
| 3182 // (2) If marking has been aborted for Full GC, then we also abort. | |
| 3183 if (_cm->has_aborted()) { | |
| 3184 set_has_aborted(); | |
| 3185 statsOnly( ++_aborted_cm_aborted ); | |
| 3186 return; | |
| 3187 } | |
| 3188 | |
| 3189 double curr_time_ms = os::elapsedVTime() * 1000.0; | |
| 3190 | |
| 3191 // (3) If marking stats are enabled, then we update the step history. | |
| 3192 #if _MARKING_STATS_ | |
| 3193 if (_words_scanned >= _words_scanned_limit) | |
| 3194 ++_clock_due_to_scanning; | |
| 3195 if (_refs_reached >= _refs_reached_limit) | |
| 3196 ++_clock_due_to_marking; | |
| 3197 | |
| 3198 double last_interval_ms = curr_time_ms - _interval_start_time_ms; | |
| 3199 _interval_start_time_ms = curr_time_ms; | |
| 3200 _all_clock_intervals_ms.add(last_interval_ms); | |
| 3201 | |
| 3202 if (_cm->verbose_medium()) { | |
| 3203 gclog_or_tty->print_cr("[%d] regular clock, interval = %1.2lfms, " | |
| 3204 "scanned = %d%s, refs reached = %d%s", | |
| 3205 _task_id, last_interval_ms, | |
| 3206 _words_scanned, | |
| 3207 (_words_scanned >= _words_scanned_limit) ? " (*)" : "", | |
| 3208 _refs_reached, | |
| 3209 (_refs_reached >= _refs_reached_limit) ? " (*)" : ""); | |
| 3210 } | |
| 3211 #endif // _MARKING_STATS_ | |
| 3212 | |
| 3213 // (4) We check whether we should yield. If we have to, then we abort. | |
| 3214 if (_cm->should_yield()) { | |
| 3215 // We should yield. To do this we abort the task. The caller is | |
| 3216 // responsible for yielding. | |
| 3217 set_has_aborted(); | |
| 3218 statsOnly( ++_aborted_yield ); | |
| 3219 return; | |
| 3220 } | |
| 3221 | |
| 3222 // (5) We check whether we've reached our time quota. If we have, | |
| 3223 // then we abort. | |
| 3224 double elapsed_time_ms = curr_time_ms - _start_time_ms; | |
| 3225 if (elapsed_time_ms > _time_target_ms) { | |
| 3226 set_has_aborted(); | |
| 3227 _has_aborted_timed_out = true; | |
| 3228 statsOnly( ++_aborted_timed_out ); | |
| 3229 return; | |
| 3230 } | |
| 3231 | |
| 3232 // (6) Finally, we check whether there are enough completed STAB | |
| 3233 // buffers available for processing. If there are, we abort. | |
| 3234 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 3235 if (!_draining_satb_buffers && satb_mq_set.process_completed_buffers()) { | |
| 3236 if (_cm->verbose_low()) | |
| 3237 gclog_or_tty->print_cr("[%d] aborting to deal with pending SATB buffers", | |
| 3238 _task_id); | |
| 3239 // we do need to process SATB buffers, we'll abort and restart | |
| 3240 // the marking task to do so | |
| 3241 set_has_aborted(); | |
| 3242 statsOnly( ++_aborted_satb ); | |
| 3243 return; | |
| 3244 } | |
| 3245 } | |
| 3246 | |
| 3247 void CMTask::recalculate_limits() { | |
| 3248 _real_words_scanned_limit = _words_scanned + words_scanned_period; | |
| 3249 _words_scanned_limit = _real_words_scanned_limit; | |
| 3250 | |
| 3251 _real_refs_reached_limit = _refs_reached + refs_reached_period; | |
| 3252 _refs_reached_limit = _real_refs_reached_limit; | |
| 3253 } | |
| 3254 | |
| 3255 void CMTask::decrease_limits() { | |
| 3256 // This is called when we believe that we're going to do an infrequent | |
| 3257 // operation which will increase the per byte scanned cost (i.e. move | |
| 3258 // entries to/from the global stack). It basically tries to decrease the | |
| 3259 // scanning limit so that the clock is called earlier. | |
| 3260 | |
| 3261 if (_cm->verbose_medium()) | |
| 3262 gclog_or_tty->print_cr("[%d] decreasing limits", _task_id); | |
| 3263 | |
| 3264 _words_scanned_limit = _real_words_scanned_limit - | |
| 3265 3 * words_scanned_period / 4; | |
| 3266 _refs_reached_limit = _real_refs_reached_limit - | |
| 3267 3 * refs_reached_period / 4; | |
| 3268 } | |
| 3269 | |
| 3270 void CMTask::move_entries_to_global_stack() { | |
| 3271 // local array where we'll store the entries that will be popped | |
| 3272 // from the local queue | |
| 3273 oop buffer[global_stack_transfer_size]; | |
| 3274 | |
| 3275 int n = 0; | |
| 3276 oop obj; | |
| 3277 while (n < global_stack_transfer_size && _task_queue->pop_local(obj)) { | |
| 3278 buffer[n] = obj; | |
| 3279 ++n; | |
| 3280 } | |
| 3281 | |
| 3282 if (n > 0) { | |
| 3283 // we popped at least one entry from the local queue | |
| 3284 | |
| 3285 statsOnly( ++_global_transfers_to; _local_pops += n ); | |
| 3286 | |
| 3287 if (!_cm->mark_stack_push(buffer, n)) { | |
| 3288 if (_cm->verbose_low()) | |
| 3289 gclog_or_tty->print_cr("[%d] aborting due to global stack overflow", _task_id); | |
| 3290 set_has_aborted(); | |
| 3291 } else { | |
| 3292 // the transfer was successful | |
| 3293 | |
| 3294 if (_cm->verbose_medium()) | |
| 3295 gclog_or_tty->print_cr("[%d] pushed %d entries to the global stack", | |
| 3296 _task_id, n); | |
| 3297 statsOnly( int tmp_size = _cm->mark_stack_size(); | |
| 3298 if (tmp_size > _global_max_size) | |
| 3299 _global_max_size = tmp_size; | |
| 3300 _global_pushes += n ); | |
| 3301 } | |
| 3302 } | |
| 3303 | |
| 3304 // this operation was quite expensive, so decrease the limits | |
| 3305 decrease_limits(); | |
| 3306 } | |
| 3307 | |
| 3308 void CMTask::get_entries_from_global_stack() { | |
| 3309 // local array where we'll store the entries that will be popped | |
| 3310 // from the global stack. | |
| 3311 oop buffer[global_stack_transfer_size]; | |
| 3312 int n; | |
| 3313 _cm->mark_stack_pop(buffer, global_stack_transfer_size, &n); | |
|
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3314 assert(n <= global_stack_transfer_size, |
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|
3315 "we should not pop more than the given limit"); |
| 342 | 3316 if (n > 0) { |
| 3317 // yes, we did actually pop at least one entry | |
| 3318 | |
| 3319 statsOnly( ++_global_transfers_from; _global_pops += n ); | |
| 3320 if (_cm->verbose_medium()) | |
| 3321 gclog_or_tty->print_cr("[%d] popped %d entries from the global stack", | |
| 3322 _task_id, n); | |
| 3323 for (int i = 0; i < n; ++i) { | |
| 3324 bool success = _task_queue->push(buffer[i]); | |
| 3325 // We only call this when the local queue is empty or under a | |
| 3326 // given target limit. So, we do not expect this push to fail. | |
|
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3327 assert(success, "invariant"); |
| 342 | 3328 } |
| 3329 | |
| 3330 statsOnly( int tmp_size = _task_queue->size(); | |
| 3331 if (tmp_size > _local_max_size) | |
| 3332 _local_max_size = tmp_size; | |
| 3333 _local_pushes += n ); | |
| 3334 } | |
| 3335 | |
| 3336 // this operation was quite expensive, so decrease the limits | |
| 3337 decrease_limits(); | |
| 3338 } | |
| 3339 | |
| 3340 void CMTask::drain_local_queue(bool partially) { | |
| 3341 if (has_aborted()) | |
| 3342 return; | |
| 3343 | |
| 3344 // Decide what the target size is, depending whether we're going to | |
| 3345 // drain it partially (so that other tasks can steal if they run out | |
| 3346 // of things to do) or totally (at the very end). | |
| 3347 size_t target_size; | |
| 3348 if (partially) | |
| 3349 target_size = MIN2((size_t)_task_queue->max_elems()/3, GCDrainStackTargetSize); | |
| 3350 else | |
| 3351 target_size = 0; | |
| 3352 | |
| 3353 if (_task_queue->size() > target_size) { | |
| 3354 if (_cm->verbose_high()) | |
| 3355 gclog_or_tty->print_cr("[%d] draining local queue, target size = %d", | |
| 3356 _task_id, target_size); | |
| 3357 | |
| 3358 oop obj; | |
| 3359 bool ret = _task_queue->pop_local(obj); | |
| 3360 while (ret) { | |
| 3361 statsOnly( ++_local_pops ); | |
| 3362 | |
| 3363 if (_cm->verbose_high()) | |
| 3364 gclog_or_tty->print_cr("[%d] popped "PTR_FORMAT, _task_id, | |
| 3365 (void*) obj); | |
| 3366 | |
|
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|
3367 assert(_g1h->is_in_g1_reserved((HeapWord*) obj), "invariant" ); |
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3368 assert(!_g1h->heap_region_containing(obj)->is_on_free_list(), |
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|
3369 "invariant"); |
| 342 | 3370 |
| 3371 scan_object(obj); | |
| 3372 | |
| 3373 if (_task_queue->size() <= target_size || has_aborted()) | |
| 3374 ret = false; | |
| 3375 else | |
| 3376 ret = _task_queue->pop_local(obj); | |
| 3377 } | |
| 3378 | |
| 3379 if (_cm->verbose_high()) | |
| 3380 gclog_or_tty->print_cr("[%d] drained local queue, size = %d", | |
| 3381 _task_id, _task_queue->size()); | |
| 3382 } | |
| 3383 } | |
| 3384 | |
| 3385 void CMTask::drain_global_stack(bool partially) { | |
| 3386 if (has_aborted()) | |
| 3387 return; | |
| 3388 | |
| 3389 // We have a policy to drain the local queue before we attempt to | |
| 3390 // drain the global stack. | |
|
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|
3391 assert(partially || _task_queue->size() == 0, "invariant"); |
| 342 | 3392 |
| 3393 // Decide what the target size is, depending whether we're going to | |
| 3394 // drain it partially (so that other tasks can steal if they run out | |
| 3395 // of things to do) or totally (at the very end). Notice that, | |
| 3396 // because we move entries from the global stack in chunks or | |
| 3397 // because another task might be doing the same, we might in fact | |
| 3398 // drop below the target. But, this is not a problem. | |
| 3399 size_t target_size; | |
| 3400 if (partially) | |
| 3401 target_size = _cm->partial_mark_stack_size_target(); | |
| 3402 else | |
| 3403 target_size = 0; | |
| 3404 | |
| 3405 if (_cm->mark_stack_size() > target_size) { | |
| 3406 if (_cm->verbose_low()) | |
| 3407 gclog_or_tty->print_cr("[%d] draining global_stack, target size %d", | |
| 3408 _task_id, target_size); | |
| 3409 | |
| 3410 while (!has_aborted() && _cm->mark_stack_size() > target_size) { | |
| 3411 get_entries_from_global_stack(); | |
| 3412 drain_local_queue(partially); | |
| 3413 } | |
| 3414 | |
| 3415 if (_cm->verbose_low()) | |
| 3416 gclog_or_tty->print_cr("[%d] drained global stack, size = %d", | |
| 3417 _task_id, _cm->mark_stack_size()); | |
| 3418 } | |
| 3419 } | |
| 3420 | |
| 3421 // SATB Queue has several assumptions on whether to call the par or | |
| 3422 // non-par versions of the methods. this is why some of the code is | |
| 3423 // replicated. We should really get rid of the single-threaded version | |
| 3424 // of the code to simplify things. | |
| 3425 void CMTask::drain_satb_buffers() { | |
| 3426 if (has_aborted()) | |
| 3427 return; | |
| 3428 | |
| 3429 // We set this so that the regular clock knows that we're in the | |
| 3430 // middle of draining buffers and doesn't set the abort flag when it | |
| 3431 // notices that SATB buffers are available for draining. It'd be | |
| 3432 // very counter productive if it did that. :-) | |
| 3433 _draining_satb_buffers = true; | |
| 3434 | |
| 3435 CMObjectClosure oc(this); | |
| 3436 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
|
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3437 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3438 satb_mq_set.set_par_closure(_task_id, &oc); |
| 3439 else | |
| 3440 satb_mq_set.set_closure(&oc); | |
| 3441 | |
| 3442 // This keeps claiming and applying the closure to completed buffers | |
| 3443 // until we run out of buffers or we need to abort. | |
|
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3444 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 3445 while (!has_aborted() && |
| 3446 satb_mq_set.par_apply_closure_to_completed_buffer(_task_id)) { | |
| 3447 if (_cm->verbose_medium()) | |
| 3448 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3449 statsOnly( ++_satb_buffers_processed ); | |
| 3450 regular_clock_call(); | |
| 3451 } | |
| 3452 } else { | |
| 3453 while (!has_aborted() && | |
| 3454 satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 3455 if (_cm->verbose_medium()) | |
| 3456 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3457 statsOnly( ++_satb_buffers_processed ); | |
| 3458 regular_clock_call(); | |
| 3459 } | |
| 3460 } | |
| 3461 | |
| 3462 if (!concurrent() && !has_aborted()) { | |
| 3463 // We should only do this during remark. | |
|
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3464 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3465 satb_mq_set.par_iterate_closure_all_threads(_task_id); |
| 3466 else | |
| 3467 satb_mq_set.iterate_closure_all_threads(); | |
| 3468 } | |
| 3469 | |
| 3470 _draining_satb_buffers = false; | |
| 3471 | |
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3472 assert(has_aborted() || |
|
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3473 concurrent() || |
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|
3474 satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 3475 |
|
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|
3476 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3477 satb_mq_set.set_par_closure(_task_id, NULL); |
| 3478 else | |
| 3479 satb_mq_set.set_closure(NULL); | |
| 3480 | |
| 3481 // again, this was a potentially expensive operation, decrease the | |
| 3482 // limits to get the regular clock call early | |
| 3483 decrease_limits(); | |
| 3484 } | |
| 3485 | |
| 3486 void CMTask::drain_region_stack(BitMapClosure* bc) { | |
| 3487 if (has_aborted()) | |
| 3488 return; | |
| 3489 | |
|
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|
3490 assert(_region_finger == NULL, |
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|
3491 "it should be NULL when we're not scanning a region"); |
| 342 | 3492 |
|
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|
3493 if (!_cm->region_stack_empty() || !_aborted_region.is_empty()) { |
| 342 | 3494 if (_cm->verbose_low()) |
| 3495 gclog_or_tty->print_cr("[%d] draining region stack, size = %d", | |
| 3496 _task_id, _cm->region_stack_size()); | |
| 3497 | |
|
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3498 MemRegion mr; |
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3499 |
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|
3500 if (!_aborted_region.is_empty()) { |
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3501 mr = _aborted_region; |
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3502 _aborted_region = MemRegion(); |
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3503 |
|
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|
3504 if (_cm->verbose_low()) |
|
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|
3505 gclog_or_tty->print_cr("[%d] scanning aborted region [ " PTR_FORMAT ", " PTR_FORMAT " )", |
|
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3506 _task_id, mr.start(), mr.end()); |
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3507 } else { |
|
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|
3508 mr = _cm->region_stack_pop_lock_free(); |
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3509 // it returns MemRegion() if the pop fails |
|
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|
3510 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); |
|
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|
3511 } |
| 342 | 3512 |
| 3513 while (mr.start() != NULL) { | |
| 3514 if (_cm->verbose_medium()) | |
| 3515 gclog_or_tty->print_cr("[%d] we are scanning region " | |
| 3516 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 3517 _task_id, mr.start(), mr.end()); | |
|
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3518 |
|
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3519 assert(mr.end() <= _cm->finger(), |
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|
3520 "otherwise the region shouldn't be on the stack"); |
| 342 | 3521 assert(!mr.is_empty(), "Only non-empty regions live on the region stack"); |
| 3522 if (_nextMarkBitMap->iterate(bc, mr)) { | |
|
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3523 assert(!has_aborted(), |
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|
3524 "cannot abort the task without aborting the bitmap iteration"); |
| 342 | 3525 |
| 3526 // We finished iterating over the region without aborting. | |
| 3527 regular_clock_call(); | |
| 3528 if (has_aborted()) | |
| 3529 mr = MemRegion(); | |
| 3530 else { | |
|
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|
3531 mr = _cm->region_stack_pop_lock_free(); |
| 342 | 3532 // it returns MemRegion() if the pop fails |
| 3533 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); | |
| 3534 } | |
| 3535 } else { | |
|
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|
3536 assert(has_aborted(), "currently the only way to do so"); |
| 342 | 3537 |
| 3538 // The only way to abort the bitmap iteration is to return | |
| 3539 // false from the do_bit() method. However, inside the | |
| 3540 // do_bit() method we move the _region_finger to point to the | |
| 3541 // object currently being looked at. So, if we bail out, we | |
| 3542 // have definitely set _region_finger to something non-null. | |
|
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|
3543 assert(_region_finger != NULL, "invariant"); |
| 342 | 3544 |
|
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3545 // Make sure that any previously aborted region has been |
|
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|
3546 // cleared. |
|
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|
3547 assert(_aborted_region.is_empty(), "aborted region not cleared"); |
|
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|
3548 |
| 342 | 3549 // The iteration was actually aborted. So now _region_finger |
| 3550 // points to the address of the object we last scanned. If we | |
| 3551 // leave it there, when we restart this task, we will rescan | |
| 3552 // the object. It is easy to avoid this. We move the finger by | |
| 3553 // enough to point to the next possible object header (the | |
| 3554 // bitmap knows by how much we need to move it as it knows its | |
| 3555 // granularity). | |
| 3556 MemRegion newRegion = | |
| 3557 MemRegion(_nextMarkBitMap->nextWord(_region_finger), mr.end()); | |
| 3558 | |
| 3559 if (!newRegion.is_empty()) { | |
| 3560 if (_cm->verbose_low()) { | |
|
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3561 gclog_or_tty->print_cr("[%d] recording unscanned region" |
|
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|
3562 "[" PTR_FORMAT "," PTR_FORMAT ") in CMTask", |
| 342 | 3563 _task_id, |
| 3564 newRegion.start(), newRegion.end()); | |
| 3565 } | |
|
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3566 // Now record the part of the region we didn't scan to |
|
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|
3567 // make sure this task scans it later. |
|
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|
3568 _aborted_region = newRegion; |
| 342 | 3569 } |
| 3570 // break from while | |
| 3571 mr = MemRegion(); | |
| 3572 } | |
| 3573 _region_finger = NULL; | |
| 3574 } | |
| 3575 | |
| 3576 if (_cm->verbose_low()) | |
| 3577 gclog_or_tty->print_cr("[%d] drained region stack, size = %d", | |
| 3578 _task_id, _cm->region_stack_size()); | |
| 3579 } | |
| 3580 } | |
| 3581 | |
| 3582 void CMTask::print_stats() { | |
| 3583 gclog_or_tty->print_cr("Marking Stats, task = %d, calls = %d", | |
| 3584 _task_id, _calls); | |
| 3585 gclog_or_tty->print_cr(" Elapsed time = %1.2lfms, Termination time = %1.2lfms", | |
| 3586 _elapsed_time_ms, _termination_time_ms); | |
| 3587 gclog_or_tty->print_cr(" Step Times (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3588 _step_times_ms.num(), _step_times_ms.avg(), | |
| 3589 _step_times_ms.sd()); | |
| 3590 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3591 _step_times_ms.maximum(), _step_times_ms.sum()); | |
| 3592 | |
| 3593 #if _MARKING_STATS_ | |
| 3594 gclog_or_tty->print_cr(" Clock Intervals (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3595 _all_clock_intervals_ms.num(), _all_clock_intervals_ms.avg(), | |
| 3596 _all_clock_intervals_ms.sd()); | |
| 3597 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3598 _all_clock_intervals_ms.maximum(), | |
| 3599 _all_clock_intervals_ms.sum()); | |
| 3600 gclog_or_tty->print_cr(" Clock Causes (cum): scanning = %d, marking = %d", | |
| 3601 _clock_due_to_scanning, _clock_due_to_marking); | |
| 3602 gclog_or_tty->print_cr(" Objects: scanned = %d, found on the bitmap = %d", | |
| 3603 _objs_scanned, _objs_found_on_bitmap); | |
| 3604 gclog_or_tty->print_cr(" Local Queue: pushes = %d, pops = %d, max size = %d", | |
| 3605 _local_pushes, _local_pops, _local_max_size); | |
| 3606 gclog_or_tty->print_cr(" Global Stack: pushes = %d, pops = %d, max size = %d", | |
| 3607 _global_pushes, _global_pops, _global_max_size); | |
| 3608 gclog_or_tty->print_cr(" transfers to = %d, transfers from = %d", | |
| 3609 _global_transfers_to,_global_transfers_from); | |
| 3610 gclog_or_tty->print_cr(" Regions: claimed = %d, Region Stack: pops = %d", | |
| 3611 _regions_claimed, _region_stack_pops); | |
| 3612 gclog_or_tty->print_cr(" SATB buffers: processed = %d", _satb_buffers_processed); | |
| 3613 gclog_or_tty->print_cr(" Steals: attempts = %d, successes = %d", | |
| 3614 _steal_attempts, _steals); | |
| 3615 gclog_or_tty->print_cr(" Aborted: %d, due to", _aborted); | |
| 3616 gclog_or_tty->print_cr(" overflow: %d, global abort: %d, yield: %d", | |
| 3617 _aborted_overflow, _aborted_cm_aborted, _aborted_yield); | |
| 3618 gclog_or_tty->print_cr(" time out: %d, SATB: %d, termination: %d", | |
| 3619 _aborted_timed_out, _aborted_satb, _aborted_termination); | |
| 3620 #endif // _MARKING_STATS_ | |
| 3621 } | |
| 3622 | |
| 3623 /***************************************************************************** | |
| 3624 | |
| 3625 The do_marking_step(time_target_ms) method is the building block | |
| 3626 of the parallel marking framework. It can be called in parallel | |
| 3627 with other invocations of do_marking_step() on different tasks | |
| 3628 (but only one per task, obviously) and concurrently with the | |
| 3629 mutator threads, or during remark, hence it eliminates the need | |
| 3630 for two versions of the code. When called during remark, it will | |
| 3631 pick up from where the task left off during the concurrent marking | |
| 3632 phase. Interestingly, tasks are also claimable during evacuation | |
| 3633 pauses too, since do_marking_step() ensures that it aborts before | |
| 3634 it needs to yield. | |
| 3635 | |
| 3636 The data structures that is uses to do marking work are the | |
| 3637 following: | |
| 3638 | |
| 3639 (1) Marking Bitmap. If there are gray objects that appear only | |
| 3640 on the bitmap (this happens either when dealing with an overflow | |
| 3641 or when the initial marking phase has simply marked the roots | |
| 3642 and didn't push them on the stack), then tasks claim heap | |
| 3643 regions whose bitmap they then scan to find gray objects. A | |
| 3644 global finger indicates where the end of the last claimed region | |
| 3645 is. A local finger indicates how far into the region a task has | |
| 3646 scanned. The two fingers are used to determine how to gray an | |
| 3647 object (i.e. whether simply marking it is OK, as it will be | |
| 3648 visited by a task in the future, or whether it needs to be also | |
| 3649 pushed on a stack). | |
| 3650 | |
| 3651 (2) Local Queue. The local queue of the task which is accessed | |
| 3652 reasonably efficiently by the task. Other tasks can steal from | |
| 3653 it when they run out of work. Throughout the marking phase, a | |
| 3654 task attempts to keep its local queue short but not totally | |
| 3655 empty, so that entries are available for stealing by other | |
| 3656 tasks. Only when there is no more work, a task will totally | |
| 3657 drain its local queue. | |
| 3658 | |
| 3659 (3) Global Mark Stack. This handles local queue overflow. During | |
| 3660 marking only sets of entries are moved between it and the local | |
| 3661 queues, as access to it requires a mutex and more fine-grain | |
| 3662 interaction with it which might cause contention. If it | |
| 3663 overflows, then the marking phase should restart and iterate | |
| 3664 over the bitmap to identify gray objects. Throughout the marking | |
| 3665 phase, tasks attempt to keep the global mark stack at a small | |
| 3666 length but not totally empty, so that entries are available for | |
| 3667 popping by other tasks. Only when there is no more work, tasks | |
| 3668 will totally drain the global mark stack. | |
| 3669 | |
| 3670 (4) Global Region Stack. Entries on it correspond to areas of | |
| 3671 the bitmap that need to be scanned since they contain gray | |
| 3672 objects. Pushes on the region stack only happen during | |
| 3673 evacuation pauses and typically correspond to areas covered by | |
| 3674 GC LABS. If it overflows, then the marking phase should restart | |
| 3675 and iterate over the bitmap to identify gray objects. Tasks will | |
| 3676 try to totally drain the region stack as soon as possible. | |
| 3677 | |
| 3678 (5) SATB Buffer Queue. This is where completed SATB buffers are | |
| 3679 made available. Buffers are regularly removed from this queue | |
| 3680 and scanned for roots, so that the queue doesn't get too | |
| 3681 long. During remark, all completed buffers are processed, as | |
| 3682 well as the filled in parts of any uncompleted buffers. | |
| 3683 | |
| 3684 The do_marking_step() method tries to abort when the time target | |
| 3685 has been reached. There are a few other cases when the | |
| 3686 do_marking_step() method also aborts: | |
| 3687 | |
| 3688 (1) When the marking phase has been aborted (after a Full GC). | |
| 3689 | |
| 3690 (2) When a global overflow (either on the global stack or the | |
| 3691 region stack) has been triggered. Before the task aborts, it | |
| 3692 will actually sync up with the other tasks to ensure that all | |
| 3693 the marking data structures (local queues, stacks, fingers etc.) | |
| 3694 are re-initialised so that when do_marking_step() completes, | |
| 3695 the marking phase can immediately restart. | |
| 3696 | |
| 3697 (3) When enough completed SATB buffers are available. The | |
| 3698 do_marking_step() method only tries to drain SATB buffers right | |
| 3699 at the beginning. So, if enough buffers are available, the | |
| 3700 marking step aborts and the SATB buffers are processed at | |
| 3701 the beginning of the next invocation. | |
| 3702 | |
| 3703 (4) To yield. when we have to yield then we abort and yield | |
| 3704 right at the end of do_marking_step(). This saves us from a lot | |
| 3705 of hassle as, by yielding we might allow a Full GC. If this | |
| 3706 happens then objects will be compacted underneath our feet, the | |
| 3707 heap might shrink, etc. We save checking for this by just | |
| 3708 aborting and doing the yield right at the end. | |
| 3709 | |
| 3710 From the above it follows that the do_marking_step() method should | |
| 3711 be called in a loop (or, otherwise, regularly) until it completes. | |
| 3712 | |
| 3713 If a marking step completes without its has_aborted() flag being | |
| 3714 true, it means it has completed the current marking phase (and | |
| 3715 also all other marking tasks have done so and have all synced up). | |
| 3716 | |
| 3717 A method called regular_clock_call() is invoked "regularly" (in | |
| 3718 sub ms intervals) throughout marking. It is this clock method that | |
| 3719 checks all the abort conditions which were mentioned above and | |
| 3720 decides when the task should abort. A work-based scheme is used to | |
| 3721 trigger this clock method: when the number of object words the | |
| 3722 marking phase has scanned or the number of references the marking | |
| 3723 phase has visited reach a given limit. Additional invocations to | |
| 3724 the method clock have been planted in a few other strategic places | |
| 3725 too. The initial reason for the clock method was to avoid calling | |
| 3726 vtime too regularly, as it is quite expensive. So, once it was in | |
| 3727 place, it was natural to piggy-back all the other conditions on it | |
| 3728 too and not constantly check them throughout the code. | |
| 3729 | |
| 3730 *****************************************************************************/ | |
| 3731 | |
| 3732 void CMTask::do_marking_step(double time_target_ms) { | |
|
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|
3733 assert(time_target_ms >= 1.0, "minimum granularity is 1ms"); |
|
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|
3734 assert(concurrent() == _cm->concurrent(), "they should be the same"); |
|
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|
3735 |
|
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|
3736 assert(concurrent() || _cm->region_stack_empty(), |
|
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|
3737 "the region stack should have been cleared before remark"); |
|
1835
4805b9f4779e
6941395: G1: Use only lock-free versions of region stack push() and pop()
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1833
diff
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|
3738 assert(concurrent() || !_cm->has_aborted_regions(), |
|
4805b9f4779e
6941395: G1: Use only lock-free versions of region stack push() and pop()
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|
3739 "aborted regions should have been cleared before remark"); |
|
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3740 assert(_region_finger == NULL, |
|
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|
3741 "this should be non-null only when a region is being scanned"); |
| 342 | 3742 |
| 3743 G1CollectorPolicy* g1_policy = _g1h->g1_policy(); | |
|
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|
3744 assert(_task_queues != NULL, "invariant"); |
|
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|
3745 assert(_task_queue != NULL, "invariant"); |
|
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3746 assert(_task_queues->queue(_task_id) == _task_queue, "invariant"); |
|
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3747 |
|
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|
3748 assert(!_claimed, |
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|
3749 "only one thread should claim this task at any one time"); |
| 342 | 3750 |
| 3751 // OK, this doesn't safeguard again all possible scenarios, as it is | |
| 3752 // possible for two threads to set the _claimed flag at the same | |
| 3753 // time. But it is only for debugging purposes anyway and it will | |
| 3754 // catch most problems. | |
| 3755 _claimed = true; | |
| 3756 | |
| 3757 _start_time_ms = os::elapsedVTime() * 1000.0; | |
| 3758 statsOnly( _interval_start_time_ms = _start_time_ms ); | |
| 3759 | |
| 3760 double diff_prediction_ms = | |
| 3761 g1_policy->get_new_prediction(&_marking_step_diffs_ms); | |
| 3762 _time_target_ms = time_target_ms - diff_prediction_ms; | |
| 3763 | |
| 3764 // set up the variables that are used in the work-based scheme to | |
| 3765 // call the regular clock method | |
| 3766 _words_scanned = 0; | |
| 3767 _refs_reached = 0; | |
| 3768 recalculate_limits(); | |
| 3769 | |
| 3770 // clear all flags | |
| 3771 clear_has_aborted(); | |
| 3772 _has_aborted_timed_out = false; | |
| 3773 _draining_satb_buffers = false; | |
| 3774 | |
| 3775 ++_calls; | |
| 3776 | |
| 3777 if (_cm->verbose_low()) | |
| 3778 gclog_or_tty->print_cr("[%d] >>>>>>>>>> START, call = %d, " | |
| 3779 "target = %1.2lfms >>>>>>>>>>", | |
| 3780 _task_id, _calls, _time_target_ms); | |
| 3781 | |
| 3782 // Set up the bitmap and oop closures. Anything that uses them is | |
| 3783 // eventually called from this method, so it is OK to allocate these | |
| 3784 // statically. | |
| 3785 CMBitMapClosure bitmap_closure(this, _cm, _nextMarkBitMap); | |
| 3786 CMOopClosure oop_closure(_g1h, _cm, this); | |
| 3787 set_oop_closure(&oop_closure); | |
| 3788 | |
| 3789 if (_cm->has_overflown()) { | |
| 3790 // This can happen if the region stack or the mark stack overflows | |
| 3791 // during a GC pause and this task, after a yield point, | |
| 3792 // restarts. We have to abort as we need to get into the overflow | |
| 3793 // protocol which happens right at the end of this task. | |
| 3794 set_has_aborted(); | |
| 3795 } | |
| 3796 | |
| 3797 // First drain any available SATB buffers. After this, we will not | |
| 3798 // look at SATB buffers before the next invocation of this method. | |
| 3799 // If enough completed SATB buffers are queued up, the regular clock | |
| 3800 // will abort this task so that it restarts. | |
| 3801 drain_satb_buffers(); | |
| 3802 // ...then partially drain the local queue and the global stack | |
| 3803 drain_local_queue(true); | |
| 3804 drain_global_stack(true); | |
| 3805 | |
| 3806 // Then totally drain the region stack. We will not look at | |
| 3807 // it again before the next invocation of this method. Entries on | |
| 3808 // the region stack are only added during evacuation pauses, for | |
| 3809 // which we have to yield. When we do, we abort the task anyway so | |
| 3810 // it will look at the region stack again when it restarts. | |
| 3811 bitmap_closure.set_scanning_heap_region(false); | |
| 3812 drain_region_stack(&bitmap_closure); | |
| 3813 // ...then partially drain the local queue and the global stack | |
| 3814 drain_local_queue(true); | |
| 3815 drain_global_stack(true); | |
| 3816 | |
| 3817 do { | |
| 3818 if (!has_aborted() && _curr_region != NULL) { | |
| 3819 // This means that we're already holding on to a region. | |
|
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|
3820 assert(_finger != NULL, "if region is not NULL, then the finger " |
|
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|
3821 "should not be NULL either"); |
| 342 | 3822 |
| 3823 // We might have restarted this task after an evacuation pause | |
| 3824 // which might have evacuated the region we're holding on to | |
| 3825 // underneath our feet. Let's read its limit again to make sure | |
| 3826 // that we do not iterate over a region of the heap that | |
| 3827 // contains garbage (update_region_limit() will also move | |
| 3828 // _finger to the start of the region if it is found empty). | |
| 3829 update_region_limit(); | |
| 3830 // We will start from _finger not from the start of the region, | |
| 3831 // as we might be restarting this task after aborting half-way | |
| 3832 // through scanning this region. In this case, _finger points to | |
| 3833 // the address where we last found a marked object. If this is a | |
| 3834 // fresh region, _finger points to start(). | |
| 3835 MemRegion mr = MemRegion(_finger, _region_limit); | |
| 3836 | |
| 3837 if (_cm->verbose_low()) | |
| 3838 gclog_or_tty->print_cr("[%d] we're scanning part " | |
| 3839 "["PTR_FORMAT", "PTR_FORMAT") " | |
| 3840 "of region "PTR_FORMAT, | |
| 3841 _task_id, _finger, _region_limit, _curr_region); | |
| 3842 | |
| 3843 // Let's iterate over the bitmap of the part of the | |
| 3844 // region that is left. | |
| 3845 bitmap_closure.set_scanning_heap_region(true); | |
| 3846 if (mr.is_empty() || | |
| 3847 _nextMarkBitMap->iterate(&bitmap_closure, mr)) { | |
| 3848 // We successfully completed iterating over the region. Now, | |
| 3849 // let's give up the region. | |
| 3850 giveup_current_region(); | |
| 3851 regular_clock_call(); | |
| 3852 } else { | |
|
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|
3853 assert(has_aborted(), "currently the only way to do so"); |
| 342 | 3854 // The only way to abort the bitmap iteration is to return |
| 3855 // false from the do_bit() method. However, inside the | |
| 3856 // do_bit() method we move the _finger to point to the | |
| 3857 // object currently being looked at. So, if we bail out, we | |
| 3858 // have definitely set _finger to something non-null. | |
|
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|
3859 assert(_finger != NULL, "invariant"); |
| 342 | 3860 |
| 3861 // Region iteration was actually aborted. So now _finger | |
| 3862 // points to the address of the object we last scanned. If we | |
| 3863 // leave it there, when we restart this task, we will rescan | |
| 3864 // the object. It is easy to avoid this. We move the finger by | |
| 3865 // enough to point to the next possible object header (the | |
| 3866 // bitmap knows by how much we need to move it as it knows its | |
| 3867 // granularity). | |
|
1314
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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1284
diff
changeset
|
3868 assert(_finger < _region_limit, "invariant"); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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diff
changeset
|
3869 HeapWord* new_finger = _nextMarkBitMap->nextWord(_finger); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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changeset
|
3870 // Check if bitmap iteration was aborted while scanning the last object |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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diff
changeset
|
3871 if (new_finger >= _region_limit) { |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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diff
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|
3872 giveup_current_region(); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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1284
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|
3873 } else { |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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diff
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|
3874 move_finger_to(new_finger); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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changeset
|
3875 } |
| 342 | 3876 } |
| 3877 } | |
| 3878 // At this point we have either completed iterating over the | |
| 3879 // region we were holding on to, or we have aborted. | |
| 3880 | |
| 3881 // We then partially drain the local queue and the global stack. | |
| 3882 // (Do we really need this?) | |
| 3883 drain_local_queue(true); | |
| 3884 drain_global_stack(true); | |
| 3885 | |
| 3886 // Read the note on the claim_region() method on why it might | |
| 3887 // return NULL with potentially more regions available for | |
| 3888 // claiming and why we have to check out_of_regions() to determine | |
| 3889 // whether we're done or not. | |
| 3890 while (!has_aborted() && _curr_region == NULL && !_cm->out_of_regions()) { | |
| 3891 // We are going to try to claim a new region. We should have | |
| 3892 // given up on the previous one. | |
|
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|
3893 // Separated the asserts so that we know which one fires. |
|
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|
3894 assert(_curr_region == NULL, "invariant"); |
|
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|
3895 assert(_finger == NULL, "invariant"); |
|
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|
3896 assert(_region_limit == NULL, "invariant"); |
| 342 | 3897 if (_cm->verbose_low()) |
| 3898 gclog_or_tty->print_cr("[%d] trying to claim a new region", _task_id); | |
| 3899 HeapRegion* claimed_region = _cm->claim_region(_task_id); | |
| 3900 if (claimed_region != NULL) { | |
| 3901 // Yes, we managed to claim one | |
| 3902 statsOnly( ++_regions_claimed ); | |
| 3903 | |
| 3904 if (_cm->verbose_low()) | |
| 3905 gclog_or_tty->print_cr("[%d] we successfully claimed " | |
| 3906 "region "PTR_FORMAT, | |
| 3907 _task_id, claimed_region); | |
| 3908 | |
| 3909 setup_for_region(claimed_region); | |
|
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|
3910 assert(_curr_region == claimed_region, "invariant"); |
| 342 | 3911 } |
| 3912 // It is important to call the regular clock here. It might take | |
| 3913 // a while to claim a region if, for example, we hit a large | |
| 3914 // block of empty regions. So we need to call the regular clock | |
| 3915 // method once round the loop to make sure it's called | |
| 3916 // frequently enough. | |
| 3917 regular_clock_call(); | |
| 3918 } | |
| 3919 | |
| 3920 if (!has_aborted() && _curr_region == NULL) { | |
|
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|
3921 assert(_cm->out_of_regions(), |
|
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|
3922 "at this point we should be out of regions"); |
| 342 | 3923 } |
| 3924 } while ( _curr_region != NULL && !has_aborted()); | |
| 3925 | |
| 3926 if (!has_aborted()) { | |
| 3927 // We cannot check whether the global stack is empty, since other | |
|
343
afc1ce1efe66
6710665: G1: guarantee(_cm->out_of_regions() && _cm->region_stack_empty() && _task_queue->size() == 0, ...)
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342
diff
changeset
|
3928 // tasks might be pushing objects to it concurrently. We also cannot |
|
afc1ce1efe66
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iveresov
parents:
342
diff
changeset
|
3929 // check if the region stack is empty because if a thread is aborting |
|
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3930 // it can push a partially done region back. |
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3931 assert(_cm->out_of_regions(), |
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3932 "at this point we should be out of regions"); |
| 342 | 3933 |
| 3934 if (_cm->verbose_low()) | |
| 3935 gclog_or_tty->print_cr("[%d] all regions claimed", _task_id); | |
| 3936 | |
| 3937 // Try to reduce the number of available SATB buffers so that | |
| 3938 // remark has less work to do. | |
| 3939 drain_satb_buffers(); | |
| 3940 } | |
| 3941 | |
| 3942 // Since we've done everything else, we can now totally drain the | |
| 3943 // local queue and global stack. | |
| 3944 drain_local_queue(false); | |
| 3945 drain_global_stack(false); | |
| 3946 | |
| 3947 // Attempt at work stealing from other task's queues. | |
| 3948 if (!has_aborted()) { | |
| 3949 // We have not aborted. This means that we have finished all that | |
| 3950 // we could. Let's try to do some stealing... | |
| 3951 | |
| 3952 // We cannot check whether the global stack is empty, since other | |
|
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3953 // tasks might be pushing objects to it concurrently. We also cannot |
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3954 // check if the region stack is empty because if a thread is aborting |
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3955 // it can push a partially done region back. |
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3956 assert(_cm->out_of_regions() && _task_queue->size() == 0, |
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3957 "only way to reach here"); |
| 342 | 3958 |
| 3959 if (_cm->verbose_low()) | |
| 3960 gclog_or_tty->print_cr("[%d] starting to steal", _task_id); | |
| 3961 | |
| 3962 while (!has_aborted()) { | |
| 3963 oop obj; | |
| 3964 statsOnly( ++_steal_attempts ); | |
| 3965 | |
| 3966 if (_cm->try_stealing(_task_id, &_hash_seed, obj)) { | |
| 3967 if (_cm->verbose_medium()) | |
| 3968 gclog_or_tty->print_cr("[%d] stolen "PTR_FORMAT" successfully", | |
| 3969 _task_id, (void*) obj); | |
| 3970 | |
| 3971 statsOnly( ++_steals ); | |
| 3972 | |
|
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3973 assert(_nextMarkBitMap->isMarked((HeapWord*) obj), |
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3974 "any stolen object should be marked"); |
| 342 | 3975 scan_object(obj); |
| 3976 | |
| 3977 // And since we're towards the end, let's totally drain the | |
| 3978 // local queue and global stack. | |
| 3979 drain_local_queue(false); | |
| 3980 drain_global_stack(false); | |
| 3981 } else { | |
| 3982 break; | |
| 3983 } | |
| 3984 } | |
| 3985 } | |
| 3986 | |
| 3987 // We still haven't aborted. Now, let's try to get into the | |
| 3988 // termination protocol. | |
| 3989 if (!has_aborted()) { | |
| 3990 // We cannot check whether the global stack is empty, since other | |
|
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3991 // tasks might be concurrently pushing objects on it. We also cannot |
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3992 // check if the region stack is empty because if a thread is aborting |
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3993 // it can push a partially done region back. |
|
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3994 // Separated the asserts so that we know which one fires. |
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3995 assert(_cm->out_of_regions(), "only way to reach here"); |
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3996 assert(_task_queue->size() == 0, "only way to reach here"); |
| 342 | 3997 |
| 3998 if (_cm->verbose_low()) | |
| 3999 gclog_or_tty->print_cr("[%d] starting termination protocol", _task_id); | |
| 4000 | |
| 4001 _termination_start_time_ms = os::elapsedVTime() * 1000.0; | |
| 4002 // The CMTask class also extends the TerminatorTerminator class, | |
| 4003 // hence its should_exit_termination() method will also decide | |
| 4004 // whether to exit the termination protocol or not. | |
| 4005 bool finished = _cm->terminator()->offer_termination(this); | |
| 4006 double termination_end_time_ms = os::elapsedVTime() * 1000.0; | |
| 4007 _termination_time_ms += | |
| 4008 termination_end_time_ms - _termination_start_time_ms; | |
| 4009 | |
| 4010 if (finished) { | |
| 4011 // We're all done. | |
| 4012 | |
| 4013 if (_task_id == 0) { | |
| 4014 // let's allow task 0 to do this | |
| 4015 if (concurrent()) { | |
|
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4016 assert(_cm->concurrent_marking_in_progress(), "invariant"); |
| 342 | 4017 // we need to set this to false before the next |
| 4018 // safepoint. This way we ensure that the marking phase | |
| 4019 // doesn't observe any more heap expansions. | |
| 4020 _cm->clear_concurrent_marking_in_progress(); | |
| 4021 } | |
| 4022 } | |
| 4023 | |
| 4024 // We can now guarantee that the global stack is empty, since | |
|
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4025 // all other tasks have finished. We separated the guarantees so |
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4026 // that, if a condition is false, we can immediately find out |
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4027 // which one. |
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4028 guarantee(_cm->out_of_regions(), "only way to reach here"); |
|
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4029 guarantee(_aborted_region.is_empty(), "only way to reach here"); |
|
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|
4030 guarantee(_cm->region_stack_empty(), "only way to reach here"); |
|
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4031 guarantee(_cm->mark_stack_empty(), "only way to reach here"); |
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|
4032 guarantee(_task_queue->size() == 0, "only way to reach here"); |
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4033 guarantee(!_cm->has_overflown(), "only way to reach here"); |
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|
4034 guarantee(!_cm->mark_stack_overflow(), "only way to reach here"); |
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|
4035 guarantee(!_cm->region_stack_overflow(), "only way to reach here"); |
| 342 | 4036 |
| 4037 if (_cm->verbose_low()) | |
| 4038 gclog_or_tty->print_cr("[%d] all tasks terminated", _task_id); | |
| 4039 } else { | |
| 4040 // Apparently there's more work to do. Let's abort this task. It | |
| 4041 // will restart it and we can hopefully find more things to do. | |
| 4042 | |
| 4043 if (_cm->verbose_low()) | |
| 4044 gclog_or_tty->print_cr("[%d] apparently there is more work to do", _task_id); | |
| 4045 | |
| 4046 set_has_aborted(); | |
| 4047 statsOnly( ++_aborted_termination ); | |
| 4048 } | |
| 4049 } | |
| 4050 | |
| 4051 // Mainly for debugging purposes to make sure that a pointer to the | |
| 4052 // closure which was statically allocated in this frame doesn't | |
| 4053 // escape it by accident. | |
| 4054 set_oop_closure(NULL); | |
| 4055 double end_time_ms = os::elapsedVTime() * 1000.0; | |
| 4056 double elapsed_time_ms = end_time_ms - _start_time_ms; | |
| 4057 // Update the step history. | |
| 4058 _step_times_ms.add(elapsed_time_ms); | |
| 4059 | |
| 4060 if (has_aborted()) { | |
| 4061 // The task was aborted for some reason. | |
| 4062 | |
| 4063 statsOnly( ++_aborted ); | |
| 4064 | |
| 4065 if (_has_aborted_timed_out) { | |
| 4066 double diff_ms = elapsed_time_ms - _time_target_ms; | |
| 4067 // Keep statistics of how well we did with respect to hitting | |
| 4068 // our target only if we actually timed out (if we aborted for | |
| 4069 // other reasons, then the results might get skewed). | |
| 4070 _marking_step_diffs_ms.add(diff_ms); | |
| 4071 } | |
| 4072 | |
| 4073 if (_cm->has_overflown()) { | |
| 4074 // This is the interesting one. We aborted because a global | |
| 4075 // overflow was raised. This means we have to restart the | |
| 4076 // marking phase and start iterating over regions. However, in | |
| 4077 // order to do this we have to make sure that all tasks stop | |
| 4078 // what they are doing and re-initialise in a safe manner. We | |
| 4079 // will achieve this with the use of two barrier sync points. | |
| 4080 | |
| 4081 if (_cm->verbose_low()) | |
| 4082 gclog_or_tty->print_cr("[%d] detected overflow", _task_id); | |
| 4083 | |
| 4084 _cm->enter_first_sync_barrier(_task_id); | |
| 4085 // When we exit this sync barrier we know that all tasks have | |
| 4086 // stopped doing marking work. So, it's now safe to | |
| 4087 // re-initialise our data structures. At the end of this method, | |
| 4088 // task 0 will clear the global data structures. | |
| 4089 | |
| 4090 statsOnly( ++_aborted_overflow ); | |
| 4091 | |
| 4092 // We clear the local state of this task... | |
| 4093 clear_region_fields(); | |
| 4094 | |
| 4095 // ...and enter the second barrier. | |
| 4096 _cm->enter_second_sync_barrier(_task_id); | |
| 4097 // At this point everything has bee re-initialised and we're | |
| 4098 // ready to restart. | |
| 4099 } | |
| 4100 | |
| 4101 if (_cm->verbose_low()) { | |
| 4102 gclog_or_tty->print_cr("[%d] <<<<<<<<<< ABORTING, target = %1.2lfms, " | |
| 4103 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4104 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4105 if (_cm->has_aborted()) | |
| 4106 gclog_or_tty->print_cr("[%d] ========== MARKING ABORTED ==========", | |
| 4107 _task_id); | |
| 4108 } | |
| 4109 } else { | |
| 4110 if (_cm->verbose_low()) | |
| 4111 gclog_or_tty->print_cr("[%d] <<<<<<<<<< FINISHED, target = %1.2lfms, " | |
| 4112 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4113 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4114 } | |
| 4115 | |
| 4116 _claimed = false; | |
| 4117 } | |
| 4118 | |
| 4119 CMTask::CMTask(int task_id, | |
| 4120 ConcurrentMark* cm, | |
| 4121 CMTaskQueue* task_queue, | |
| 4122 CMTaskQueueSet* task_queues) | |
| 4123 : _g1h(G1CollectedHeap::heap()), | |
| 4124 _task_id(task_id), _cm(cm), | |
| 4125 _claimed(false), | |
| 4126 _nextMarkBitMap(NULL), _hash_seed(17), | |
| 4127 _task_queue(task_queue), | |
| 4128 _task_queues(task_queues), | |
|
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4129 _oop_closure(NULL), |
|
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|
4130 _aborted_region(MemRegion()) { |
|
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4131 guarantee(task_queue != NULL, "invariant"); |
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|
4132 guarantee(task_queues != NULL, "invariant"); |
| 342 | 4133 |
| 4134 statsOnly( _clock_due_to_scanning = 0; | |
| 4135 _clock_due_to_marking = 0 ); | |
| 4136 | |
| 4137 _marking_step_diffs_ms.add(0.5); | |
| 4138 } |