Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/concurrentMark.cpp @ 1972:f95d63e2154a
6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg
| author | stefank |
|---|---|
| date | Tue, 23 Nov 2010 13:22:55 -0800 |
| parents | a5c514e74487 |
| children | fd1d227ef1b9 |
| 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" | |
| 34 #include "memory/genOopClosures.inline.hpp" | |
| 35 #include "memory/referencePolicy.hpp" | |
| 36 #include "memory/resourceArea.hpp" | |
| 37 #include "oops/oop.inline.hpp" | |
| 38 #include "runtime/handles.inline.hpp" | |
| 39 #include "runtime/java.hpp" | |
| 342 | 40 |
| 41 // | |
| 42 // CMS Bit Map Wrapper | |
| 43 | |
| 44 CMBitMapRO::CMBitMapRO(ReservedSpace rs, int shifter): | |
| 45 _bm((uintptr_t*)NULL,0), | |
| 46 _shifter(shifter) { | |
| 47 _bmStartWord = (HeapWord*)(rs.base()); | |
| 48 _bmWordSize = rs.size()/HeapWordSize; // rs.size() is in bytes | |
| 49 ReservedSpace brs(ReservedSpace::allocation_align_size_up( | |
| 50 (_bmWordSize >> (_shifter + LogBitsPerByte)) + 1)); | |
| 51 | |
| 52 guarantee(brs.is_reserved(), "couldn't allocate CMS bit map"); | |
| 53 // For now we'll just commit all of the bit map up fromt. | |
| 54 // Later on we'll try to be more parsimonious with swap. | |
| 55 guarantee(_virtual_space.initialize(brs, brs.size()), | |
| 56 "couldn't reseve backing store for CMS bit map"); | |
| 57 assert(_virtual_space.committed_size() == brs.size(), | |
| 58 "didn't reserve backing store for all of CMS bit map?"); | |
| 59 _bm.set_map((uintptr_t*)_virtual_space.low()); | |
| 60 assert(_virtual_space.committed_size() << (_shifter + LogBitsPerByte) >= | |
| 61 _bmWordSize, "inconsistency in bit map sizing"); | |
| 62 _bm.set_size(_bmWordSize >> _shifter); | |
| 63 } | |
| 64 | |
| 65 HeapWord* CMBitMapRO::getNextMarkedWordAddress(HeapWord* addr, | |
| 66 HeapWord* limit) const { | |
| 67 // First we must round addr *up* to a possible object boundary. | |
| 68 addr = (HeapWord*)align_size_up((intptr_t)addr, | |
| 69 HeapWordSize << _shifter); | |
| 70 size_t addrOffset = heapWordToOffset(addr); | |
| 71 if (limit == NULL) limit = _bmStartWord + _bmWordSize; | |
| 72 size_t limitOffset = heapWordToOffset(limit); | |
| 73 size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset); | |
| 74 HeapWord* nextAddr = offsetToHeapWord(nextOffset); | |
| 75 assert(nextAddr >= addr, "get_next_one postcondition"); | |
| 76 assert(nextAddr == limit || isMarked(nextAddr), | |
| 77 "get_next_one postcondition"); | |
| 78 return nextAddr; | |
| 79 } | |
| 80 | |
| 81 HeapWord* CMBitMapRO::getNextUnmarkedWordAddress(HeapWord* addr, | |
| 82 HeapWord* limit) const { | |
| 83 size_t addrOffset = heapWordToOffset(addr); | |
| 84 if (limit == NULL) limit = _bmStartWord + _bmWordSize; | |
| 85 size_t limitOffset = heapWordToOffset(limit); | |
| 86 size_t nextOffset = _bm.get_next_zero_offset(addrOffset, limitOffset); | |
| 87 HeapWord* nextAddr = offsetToHeapWord(nextOffset); | |
| 88 assert(nextAddr >= addr, "get_next_one postcondition"); | |
| 89 assert(nextAddr == limit || !isMarked(nextAddr), | |
| 90 "get_next_one postcondition"); | |
| 91 return nextAddr; | |
| 92 } | |
| 93 | |
| 94 int CMBitMapRO::heapWordDiffToOffsetDiff(size_t diff) const { | |
| 95 assert((diff & ((1 << _shifter) - 1)) == 0, "argument check"); | |
| 96 return (int) (diff >> _shifter); | |
| 97 } | |
| 98 | |
| 99 bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { | |
| 100 HeapWord* left = MAX2(_bmStartWord, mr.start()); | |
| 101 HeapWord* right = MIN2(_bmStartWord + _bmWordSize, mr.end()); | |
| 102 if (right > left) { | |
| 103 // Right-open interval [leftOffset, rightOffset). | |
| 104 return _bm.iterate(cl, heapWordToOffset(left), heapWordToOffset(right)); | |
| 105 } else { | |
| 106 return true; | |
| 107 } | |
| 108 } | |
| 109 | |
| 110 void CMBitMapRO::mostly_disjoint_range_union(BitMap* from_bitmap, | |
| 111 size_t from_start_index, | |
| 112 HeapWord* to_start_word, | |
| 113 size_t word_num) { | |
| 114 _bm.mostly_disjoint_range_union(from_bitmap, | |
| 115 from_start_index, | |
| 116 heapWordToOffset(to_start_word), | |
| 117 word_num); | |
| 118 } | |
| 119 | |
| 120 #ifndef PRODUCT | |
| 121 bool CMBitMapRO::covers(ReservedSpace rs) const { | |
| 122 // assert(_bm.map() == _virtual_space.low(), "map inconsistency"); | |
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123 assert(((size_t)_bm.size() * (size_t)(1 << _shifter)) == _bmWordSize, |
| 342 | 124 "size inconsistency"); |
| 125 return _bmStartWord == (HeapWord*)(rs.base()) && | |
| 126 _bmWordSize == rs.size()>>LogHeapWordSize; | |
| 127 } | |
| 128 #endif | |
| 129 | |
| 130 void CMBitMap::clearAll() { | |
| 131 _bm.clear(); | |
| 132 return; | |
| 133 } | |
| 134 | |
| 135 void CMBitMap::markRange(MemRegion mr) { | |
| 136 mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 137 assert(!mr.is_empty(), "unexpected empty region"); | |
| 138 assert((offsetToHeapWord(heapWordToOffset(mr.end())) == | |
| 139 ((HeapWord *) mr.end())), | |
| 140 "markRange memory region end is not card aligned"); | |
| 141 // convert address range into offset range | |
| 142 _bm.at_put_range(heapWordToOffset(mr.start()), | |
| 143 heapWordToOffset(mr.end()), true); | |
| 144 } | |
| 145 | |
| 146 void CMBitMap::clearRange(MemRegion mr) { | |
| 147 mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 148 assert(!mr.is_empty(), "unexpected empty region"); | |
| 149 // convert address range into offset range | |
| 150 _bm.at_put_range(heapWordToOffset(mr.start()), | |
| 151 heapWordToOffset(mr.end()), false); | |
| 152 } | |
| 153 | |
| 154 MemRegion CMBitMap::getAndClearMarkedRegion(HeapWord* addr, | |
| 155 HeapWord* end_addr) { | |
| 156 HeapWord* start = getNextMarkedWordAddress(addr); | |
| 157 start = MIN2(start, end_addr); | |
| 158 HeapWord* end = getNextUnmarkedWordAddress(start); | |
| 159 end = MIN2(end, end_addr); | |
| 160 assert(start <= end, "Consistency check"); | |
| 161 MemRegion mr(start, end); | |
| 162 if (!mr.is_empty()) { | |
| 163 clearRange(mr); | |
| 164 } | |
| 165 return mr; | |
| 166 } | |
| 167 | |
| 168 CMMarkStack::CMMarkStack(ConcurrentMark* cm) : | |
| 169 _base(NULL), _cm(cm) | |
| 170 #ifdef ASSERT | |
| 171 , _drain_in_progress(false) | |
| 172 , _drain_in_progress_yields(false) | |
| 173 #endif | |
| 174 {} | |
| 175 | |
| 176 void CMMarkStack::allocate(size_t size) { | |
| 177 _base = NEW_C_HEAP_ARRAY(oop, size); | |
| 178 if (_base == NULL) | |
| 179 vm_exit_during_initialization("Failed to allocate " | |
| 180 "CM region mark stack"); | |
| 181 _index = 0; | |
| 182 // QQQQ cast ... | |
| 183 _capacity = (jint) size; | |
| 184 _oops_do_bound = -1; | |
| 185 NOT_PRODUCT(_max_depth = 0); | |
| 186 } | |
| 187 | |
| 188 CMMarkStack::~CMMarkStack() { | |
| 189 if (_base != NULL) FREE_C_HEAP_ARRAY(oop, _base); | |
| 190 } | |
| 191 | |
| 192 void CMMarkStack::par_push(oop ptr) { | |
| 193 while (true) { | |
| 194 if (isFull()) { | |
| 195 _overflow = true; | |
| 196 return; | |
| 197 } | |
| 198 // Otherwise... | |
| 199 jint index = _index; | |
| 200 jint next_index = index+1; | |
| 201 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 202 if (res == index) { | |
| 203 _base[index] = ptr; | |
| 204 // Note that we don't maintain this atomically. We could, but it | |
| 205 // doesn't seem necessary. | |
| 206 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index)); | |
| 207 return; | |
| 208 } | |
| 209 // Otherwise, we need to try again. | |
| 210 } | |
| 211 } | |
| 212 | |
| 213 void CMMarkStack::par_adjoin_arr(oop* ptr_arr, int n) { | |
| 214 while (true) { | |
| 215 if (isFull()) { | |
| 216 _overflow = true; | |
| 217 return; | |
| 218 } | |
| 219 // Otherwise... | |
| 220 jint index = _index; | |
| 221 jint next_index = index + n; | |
| 222 if (next_index > _capacity) { | |
| 223 _overflow = true; | |
| 224 return; | |
| 225 } | |
| 226 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 227 if (res == index) { | |
| 228 for (int i = 0; i < n; i++) { | |
| 229 int ind = index + i; | |
| 230 assert(ind < _capacity, "By overflow test above."); | |
| 231 _base[ind] = ptr_arr[i]; | |
| 232 } | |
| 233 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index)); | |
| 234 return; | |
| 235 } | |
| 236 // Otherwise, we need to try again. | |
| 237 } | |
| 238 } | |
| 239 | |
| 240 | |
| 241 void CMMarkStack::par_push_arr(oop* ptr_arr, int n) { | |
| 242 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 243 jint start = _index; | |
| 244 jint next_index = start + n; | |
| 245 if (next_index > _capacity) { | |
| 246 _overflow = true; | |
| 247 return; | |
| 248 } | |
| 249 // Otherwise. | |
| 250 _index = next_index; | |
| 251 for (int i = 0; i < n; i++) { | |
| 252 int ind = start + i; | |
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253 assert(ind < _capacity, "By overflow test above."); |
| 342 | 254 _base[ind] = ptr_arr[i]; |
| 255 } | |
| 256 } | |
| 257 | |
| 258 | |
| 259 bool CMMarkStack::par_pop_arr(oop* ptr_arr, int max, int* n) { | |
| 260 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 261 jint index = _index; | |
| 262 if (index == 0) { | |
| 263 *n = 0; | |
| 264 return false; | |
| 265 } else { | |
| 266 int k = MIN2(max, index); | |
| 267 jint new_ind = index - k; | |
| 268 for (int j = 0; j < k; j++) { | |
| 269 ptr_arr[j] = _base[new_ind + j]; | |
| 270 } | |
| 271 _index = new_ind; | |
| 272 *n = k; | |
| 273 return true; | |
| 274 } | |
| 275 } | |
| 276 | |
| 277 | |
| 278 CMRegionStack::CMRegionStack() : _base(NULL) {} | |
| 279 | |
| 280 void CMRegionStack::allocate(size_t size) { | |
| 281 _base = NEW_C_HEAP_ARRAY(MemRegion, size); | |
| 282 if (_base == NULL) | |
| 283 vm_exit_during_initialization("Failed to allocate " | |
| 284 "CM region mark stack"); | |
| 285 _index = 0; | |
| 286 // QQQQ cast ... | |
| 287 _capacity = (jint) size; | |
| 288 } | |
| 289 | |
| 290 CMRegionStack::~CMRegionStack() { | |
| 291 if (_base != NULL) FREE_C_HEAP_ARRAY(oop, _base); | |
| 292 } | |
| 293 | |
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294 void CMRegionStack::push_lock_free(MemRegion mr) { |
| 342 | 295 assert(mr.word_size() > 0, "Precondition"); |
| 296 while (true) { | |
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297 jint index = _index; |
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298 |
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299 if (index >= _capacity) { |
| 342 | 300 _overflow = true; |
| 301 return; | |
| 302 } | |
| 303 // Otherwise... | |
| 304 jint next_index = index+1; | |
| 305 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 306 if (res == index) { | |
| 307 _base[index] = mr; | |
| 308 return; | |
| 309 } | |
| 310 // Otherwise, we need to try again. | |
| 311 } | |
| 312 } | |
| 313 | |
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314 // Lock-free pop of the region stack. Called during the concurrent |
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315 // marking / remark phases. Should only be called in tandem with |
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316 // other lock-free pops. |
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317 MemRegion CMRegionStack::pop_lock_free() { |
| 342 | 318 while (true) { |
| 319 jint index = _index; | |
| 320 | |
| 321 if (index == 0) { | |
| 322 return MemRegion(); | |
| 323 } | |
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324 // Otherwise... |
| 342 | 325 jint next_index = index-1; |
| 326 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 327 if (res == index) { | |
| 328 MemRegion mr = _base[next_index]; | |
| 329 if (mr.start() != NULL) { | |
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330 assert(mr.end() != NULL, "invariant"); |
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331 assert(mr.word_size() > 0, "invariant"); |
| 342 | 332 return mr; |
| 333 } else { | |
| 334 // that entry was invalidated... let's skip it | |
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335 assert(mr.end() == NULL, "invariant"); |
| 342 | 336 } |
| 337 } | |
| 338 // Otherwise, we need to try again. | |
| 339 } | |
| 340 } | |
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341 |
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342 #if 0 |
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343 // The routines that manipulate the region stack with a lock are |
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344 // not currently used. They should be retained, however, as a |
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345 // diagnostic aid. |
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346 |
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347 void CMRegionStack::push_with_lock(MemRegion mr) { |
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348 assert(mr.word_size() > 0, "Precondition"); |
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349 MutexLockerEx x(CMRegionStack_lock, Mutex::_no_safepoint_check_flag); |
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350 |
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351 if (isFull()) { |
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352 _overflow = true; |
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353 return; |
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354 } |
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355 |
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356 _base[_index] = mr; |
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357 _index += 1; |
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358 } |
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359 |
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360 MemRegion CMRegionStack::pop_with_lock() { |
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361 MutexLockerEx x(CMRegionStack_lock, Mutex::_no_safepoint_check_flag); |
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362 |
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363 while (true) { |
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364 if (_index == 0) { |
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365 return MemRegion(); |
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366 } |
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367 _index -= 1; |
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368 |
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369 MemRegion mr = _base[_index]; |
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370 if (mr.start() != NULL) { |
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371 assert(mr.end() != NULL, "invariant"); |
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372 assert(mr.word_size() > 0, "invariant"); |
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373 return mr; |
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374 } else { |
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375 // that entry was invalidated... let's skip it |
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376 assert(mr.end() == NULL, "invariant"); |
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377 } |
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378 } |
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379 } |
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380 #endif |
| 342 | 381 |
| 382 bool CMRegionStack::invalidate_entries_into_cset() { | |
| 383 bool result = false; | |
| 384 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 385 for (int i = 0; i < _oops_do_bound; ++i) { | |
| 386 MemRegion mr = _base[i]; | |
| 387 if (mr.start() != NULL) { | |
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388 assert(mr.end() != NULL, "invariant"); |
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389 assert(mr.word_size() > 0, "invariant"); |
| 342 | 390 HeapRegion* hr = g1h->heap_region_containing(mr.start()); |
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391 assert(hr != NULL, "invariant"); |
| 342 | 392 if (hr->in_collection_set()) { |
| 393 // The region points into the collection set | |
| 394 _base[i] = MemRegion(); | |
| 395 result = true; | |
| 396 } | |
| 397 } else { | |
| 398 // that entry was invalidated... let's skip it | |
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399 assert(mr.end() == NULL, "invariant"); |
| 342 | 400 } |
| 401 } | |
| 402 return result; | |
| 403 } | |
| 404 | |
| 405 template<class OopClosureClass> | |
| 406 bool CMMarkStack::drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after) { | |
| 407 assert(!_drain_in_progress || !_drain_in_progress_yields || yield_after | |
| 408 || SafepointSynchronize::is_at_safepoint(), | |
| 409 "Drain recursion must be yield-safe."); | |
| 410 bool res = true; | |
| 411 debug_only(_drain_in_progress = true); | |
| 412 debug_only(_drain_in_progress_yields = yield_after); | |
| 413 while (!isEmpty()) { | |
| 414 oop newOop = pop(); | |
| 415 assert(G1CollectedHeap::heap()->is_in_reserved(newOop), "Bad pop"); | |
| 416 assert(newOop->is_oop(), "Expected an oop"); | |
| 417 assert(bm == NULL || bm->isMarked((HeapWord*)newOop), | |
| 418 "only grey objects on this stack"); | |
| 419 // iterate over the oops in this oop, marking and pushing | |
| 420 // the ones in CMS generation. | |
| 421 newOop->oop_iterate(cl); | |
| 422 if (yield_after && _cm->do_yield_check()) { | |
| 423 res = false; break; | |
| 424 } | |
| 425 } | |
| 426 debug_only(_drain_in_progress = false); | |
| 427 return res; | |
| 428 } | |
| 429 | |
| 430 void CMMarkStack::oops_do(OopClosure* f) { | |
| 431 if (_index == 0) return; | |
| 432 assert(_oops_do_bound != -1 && _oops_do_bound <= _index, | |
| 433 "Bound must be set."); | |
| 434 for (int i = 0; i < _oops_do_bound; i++) { | |
| 435 f->do_oop(&_base[i]); | |
| 436 } | |
| 437 _oops_do_bound = -1; | |
| 438 } | |
| 439 | |
| 440 bool ConcurrentMark::not_yet_marked(oop obj) const { | |
| 441 return (_g1h->is_obj_ill(obj) | |
| 442 || (_g1h->is_in_permanent(obj) | |
| 443 && !nextMarkBitMap()->isMarked((HeapWord*)obj))); | |
| 444 } | |
| 445 | |
| 446 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away | |
| 447 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list | |
| 448 #endif // _MSC_VER | |
| 449 | |
| 450 ConcurrentMark::ConcurrentMark(ReservedSpace rs, | |
| 451 int max_regions) : | |
| 452 _markBitMap1(rs, MinObjAlignment - 1), | |
| 453 _markBitMap2(rs, MinObjAlignment - 1), | |
| 454 | |
| 455 _parallel_marking_threads(0), | |
| 456 _sleep_factor(0.0), | |
| 457 _marking_task_overhead(1.0), | |
| 458 _cleanup_sleep_factor(0.0), | |
| 459 _cleanup_task_overhead(1.0), | |
| 460 _region_bm(max_regions, false /* in_resource_area*/), | |
| 461 _card_bm((rs.size() + CardTableModRefBS::card_size - 1) >> | |
| 462 CardTableModRefBS::card_shift, | |
| 463 false /* in_resource_area*/), | |
| 464 _prevMarkBitMap(&_markBitMap1), | |
| 465 _nextMarkBitMap(&_markBitMap2), | |
| 466 _at_least_one_mark_complete(false), | |
| 467 | |
| 468 _markStack(this), | |
| 469 _regionStack(), | |
| 470 // _finger set in set_non_marking_state | |
| 471 | |
| 472 _max_task_num(MAX2(ParallelGCThreads, (size_t)1)), | |
| 473 // _active_tasks set in set_non_marking_state | |
| 474 // _tasks set inside the constructor | |
| 475 _task_queues(new CMTaskQueueSet((int) _max_task_num)), | |
| 476 _terminator(ParallelTaskTerminator((int) _max_task_num, _task_queues)), | |
| 477 | |
| 478 _has_overflown(false), | |
| 479 _concurrent(false), | |
|
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480 _has_aborted(false), |
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481 _restart_for_overflow(false), |
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482 _concurrent_marking_in_progress(false), |
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483 _should_gray_objects(false), |
| 342 | 484 |
| 485 // _verbose_level set below | |
| 486 | |
| 487 _init_times(), | |
| 488 _remark_times(), _remark_mark_times(), _remark_weak_ref_times(), | |
| 489 _cleanup_times(), | |
| 490 _total_counting_time(0.0), | |
| 491 _total_rs_scrub_time(0.0), | |
| 492 | |
| 936 | 493 _parallel_workers(NULL) |
| 342 | 494 { |
| 495 CMVerboseLevel verbose_level = | |
| 496 (CMVerboseLevel) G1MarkingVerboseLevel; | |
| 497 if (verbose_level < no_verbose) | |
| 498 verbose_level = no_verbose; | |
| 499 if (verbose_level > high_verbose) | |
| 500 verbose_level = high_verbose; | |
| 501 _verbose_level = verbose_level; | |
| 502 | |
| 503 if (verbose_low()) | |
| 504 gclog_or_tty->print_cr("[global] init, heap start = "PTR_FORMAT", " | |
| 505 "heap end = "PTR_FORMAT, _heap_start, _heap_end); | |
| 506 | |
| 1284 | 507 _markStack.allocate(MarkStackSize); |
| 751 | 508 _regionStack.allocate(G1MarkRegionStackSize); |
| 342 | 509 |
| 510 // Create & start a ConcurrentMark thread. | |
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511 _cmThread = new ConcurrentMarkThread(this); |
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512 assert(cmThread() != NULL, "CM Thread should have been created"); |
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513 assert(cmThread()->cm() != NULL, "CM Thread should refer to this cm"); |
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514 |
| 342 | 515 _g1h = G1CollectedHeap::heap(); |
| 516 assert(CGC_lock != NULL, "Where's the CGC_lock?"); | |
| 517 assert(_markBitMap1.covers(rs), "_markBitMap1 inconsistency"); | |
| 518 assert(_markBitMap2.covers(rs), "_markBitMap2 inconsistency"); | |
| 519 | |
| 520 SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set(); | |
| 1282 | 521 satb_qs.set_buffer_size(G1SATBBufferSize); |
| 342 | 522 |
| 523 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 524 _par_cleanup_thread_state = NEW_C_HEAP_ARRAY(ParCleanupThreadState*, size); | |
| 525 for (int i = 0 ; i < size; i++) { | |
| 526 _par_cleanup_thread_state[i] = new ParCleanupThreadState; | |
| 527 } | |
| 528 | |
| 529 _tasks = NEW_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 530 _accum_task_vtime = NEW_C_HEAP_ARRAY(double, _max_task_num); | |
| 531 | |
| 532 // so that the assertion in MarkingTaskQueue::task_queue doesn't fail | |
| 533 _active_tasks = _max_task_num; | |
| 534 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 535 CMTaskQueue* task_queue = new CMTaskQueue(); | |
| 536 task_queue->initialize(); | |
| 537 _task_queues->register_queue(i, task_queue); | |
| 538 | |
| 539 _tasks[i] = new CMTask(i, this, task_queue, _task_queues); | |
| 540 _accum_task_vtime[i] = 0.0; | |
| 541 } | |
| 542 | |
| 1284 | 543 if (ConcGCThreads > ParallelGCThreads) { |
| 544 vm_exit_during_initialization("Can't have more ConcGCThreads " | |
| 342 | 545 "than ParallelGCThreads."); |
| 546 } | |
| 547 if (ParallelGCThreads == 0) { | |
| 548 // if we are not running with any parallel GC threads we will not | |
| 549 // spawn any marking threads either | |
| 550 _parallel_marking_threads = 0; | |
| 551 _sleep_factor = 0.0; | |
| 552 _marking_task_overhead = 1.0; | |
| 553 } else { | |
| 1284 | 554 if (ConcGCThreads > 0) { |
| 555 // notice that ConcGCThreads overwrites G1MarkingOverheadPercent | |
| 342 | 556 // if both are set |
| 557 | |
| 1284 | 558 _parallel_marking_threads = ConcGCThreads; |
| 342 | 559 _sleep_factor = 0.0; |
| 560 _marking_task_overhead = 1.0; | |
| 751 | 561 } else if (G1MarkingOverheadPercent > 0) { |
| 342 | 562 // we will calculate the number of parallel marking threads |
| 563 // based on a target overhead with respect to the soft real-time | |
| 564 // goal | |
| 565 | |
| 751 | 566 double marking_overhead = (double) G1MarkingOverheadPercent / 100.0; |
| 342 | 567 double overall_cm_overhead = |
| 751 | 568 (double) MaxGCPauseMillis * marking_overhead / |
| 569 (double) GCPauseIntervalMillis; | |
| 342 | 570 double cpu_ratio = 1.0 / (double) os::processor_count(); |
| 571 double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio); | |
| 572 double marking_task_overhead = | |
| 573 overall_cm_overhead / marking_thread_num * | |
| 574 (double) os::processor_count(); | |
| 575 double sleep_factor = | |
| 576 (1.0 - marking_task_overhead) / marking_task_overhead; | |
| 577 | |
| 578 _parallel_marking_threads = (size_t) marking_thread_num; | |
| 579 _sleep_factor = sleep_factor; | |
| 580 _marking_task_overhead = marking_task_overhead; | |
| 581 } else { | |
| 582 _parallel_marking_threads = MAX2((ParallelGCThreads + 2) / 4, (size_t)1); | |
| 583 _sleep_factor = 0.0; | |
| 584 _marking_task_overhead = 1.0; | |
| 585 } | |
| 586 | |
| 587 if (parallel_marking_threads() > 1) | |
| 588 _cleanup_task_overhead = 1.0; | |
| 589 else | |
| 590 _cleanup_task_overhead = marking_task_overhead(); | |
| 591 _cleanup_sleep_factor = | |
| 592 (1.0 - cleanup_task_overhead()) / cleanup_task_overhead(); | |
| 593 | |
| 594 #if 0 | |
| 595 gclog_or_tty->print_cr("Marking Threads %d", parallel_marking_threads()); | |
| 596 gclog_or_tty->print_cr("CM Marking Task Overhead %1.4lf", marking_task_overhead()); | |
| 597 gclog_or_tty->print_cr("CM Sleep Factor %1.4lf", sleep_factor()); | |
| 598 gclog_or_tty->print_cr("CL Marking Task Overhead %1.4lf", cleanup_task_overhead()); | |
| 599 gclog_or_tty->print_cr("CL Sleep Factor %1.4lf", cleanup_sleep_factor()); | |
| 600 #endif | |
| 601 | |
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602 guarantee(parallel_marking_threads() > 0, "peace of mind"); |
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603 _parallel_workers = new FlexibleWorkGang("G1 Parallel Marking Threads", |
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604 (int) _parallel_marking_threads, false, true); |
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605 if (_parallel_workers == NULL) { |
| 342 | 606 vm_exit_during_initialization("Failed necessary allocation."); |
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607 } else { |
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608 _parallel_workers->initialize_workers(); |
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609 } |
| 342 | 610 } |
| 611 | |
| 612 // so that the call below can read a sensible value | |
| 613 _heap_start = (HeapWord*) rs.base(); | |
| 614 set_non_marking_state(); | |
| 615 } | |
| 616 | |
| 617 void ConcurrentMark::update_g1_committed(bool force) { | |
| 618 // If concurrent marking is not in progress, then we do not need to | |
| 619 // update _heap_end. This has a subtle and important | |
| 620 // side-effect. Imagine that two evacuation pauses happen between | |
| 621 // marking completion and remark. The first one can grow the | |
| 622 // heap (hence now the finger is below the heap end). Then, the | |
| 623 // second one could unnecessarily push regions on the region | |
| 624 // stack. This causes the invariant that the region stack is empty | |
| 625 // at the beginning of remark to be false. By ensuring that we do | |
| 626 // not observe heap expansions after marking is complete, then we do | |
| 627 // not have this problem. | |
| 628 if (!concurrent_marking_in_progress() && !force) | |
| 629 return; | |
| 630 | |
| 631 MemRegion committed = _g1h->g1_committed(); | |
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632 assert(committed.start() == _heap_start, "start shouldn't change"); |
| 342 | 633 HeapWord* new_end = committed.end(); |
| 634 if (new_end > _heap_end) { | |
| 635 // The heap has been expanded. | |
| 636 | |
| 637 _heap_end = new_end; | |
| 638 } | |
| 639 // Notice that the heap can also shrink. However, this only happens | |
| 640 // during a Full GC (at least currently) and the entire marking | |
| 641 // phase will bail out and the task will not be restarted. So, let's | |
| 642 // do nothing. | |
| 643 } | |
| 644 | |
| 645 void ConcurrentMark::reset() { | |
| 646 // Starting values for these two. This should be called in a STW | |
| 647 // phase. CM will be notified of any future g1_committed expansions | |
| 648 // will be at the end of evacuation pauses, when tasks are | |
| 649 // inactive. | |
| 650 MemRegion committed = _g1h->g1_committed(); | |
| 651 _heap_start = committed.start(); | |
| 652 _heap_end = committed.end(); | |
| 653 | |
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654 // Separated the asserts so that we know which one fires. |
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655 assert(_heap_start != NULL, "heap bounds should look ok"); |
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656 assert(_heap_end != NULL, "heap bounds should look ok"); |
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657 assert(_heap_start < _heap_end, "heap bounds should look ok"); |
| 342 | 658 |
| 659 // reset all the marking data structures and any necessary flags | |
| 660 clear_marking_state(); | |
| 661 | |
| 662 if (verbose_low()) | |
| 663 gclog_or_tty->print_cr("[global] resetting"); | |
| 664 | |
| 665 // We do reset all of them, since different phases will use | |
| 666 // different number of active threads. So, it's easiest to have all | |
| 667 // of them ready. | |
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668 for (int i = 0; i < (int) _max_task_num; ++i) { |
| 342 | 669 _tasks[i]->reset(_nextMarkBitMap); |
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670 } |
| 342 | 671 |
| 672 // we need this to make sure that the flag is on during the evac | |
| 673 // pause with initial mark piggy-backed | |
| 674 set_concurrent_marking_in_progress(); | |
| 675 } | |
| 676 | |
| 677 void ConcurrentMark::set_phase(size_t active_tasks, bool concurrent) { | |
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678 assert(active_tasks <= _max_task_num, "we should not have more"); |
| 342 | 679 |
| 680 _active_tasks = active_tasks; | |
| 681 // Need to update the three data structures below according to the | |
| 682 // number of active threads for this phase. | |
| 683 _terminator = ParallelTaskTerminator((int) active_tasks, _task_queues); | |
| 684 _first_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 685 _second_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 686 | |
| 687 _concurrent = concurrent; | |
| 688 // We propagate this to all tasks, not just the active ones. | |
| 689 for (int i = 0; i < (int) _max_task_num; ++i) | |
| 690 _tasks[i]->set_concurrent(concurrent); | |
| 691 | |
| 692 if (concurrent) { | |
| 693 set_concurrent_marking_in_progress(); | |
| 694 } else { | |
| 695 // We currently assume that the concurrent flag has been set to | |
| 696 // false before we start remark. At this point we should also be | |
| 697 // in a STW phase. | |
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698 assert(!concurrent_marking_in_progress(), "invariant"); |
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699 assert(_finger == _heap_end, "only way to get here"); |
| 342 | 700 update_g1_committed(true); |
| 701 } | |
| 702 } | |
| 703 | |
| 704 void ConcurrentMark::set_non_marking_state() { | |
| 705 // We set the global marking state to some default values when we're | |
| 706 // not doing marking. | |
| 707 clear_marking_state(); | |
| 708 _active_tasks = 0; | |
| 709 clear_concurrent_marking_in_progress(); | |
| 710 } | |
| 711 | |
| 712 ConcurrentMark::~ConcurrentMark() { | |
| 713 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 714 for (int i = 0; i < size; i++) delete _par_cleanup_thread_state[i]; | |
| 715 FREE_C_HEAP_ARRAY(ParCleanupThreadState*, | |
| 716 _par_cleanup_thread_state); | |
| 717 | |
| 718 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 719 delete _task_queues->queue(i); | |
| 720 delete _tasks[i]; | |
| 721 } | |
| 722 delete _task_queues; | |
| 723 FREE_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 724 } | |
| 725 | |
| 726 // This closure is used to mark refs into the g1 generation | |
| 727 // from external roots in the CMS bit map. | |
| 728 // Called at the first checkpoint. | |
| 729 // | |
| 730 | |
| 731 void ConcurrentMark::clearNextBitmap() { | |
|
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732 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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733 G1CollectorPolicy* g1p = g1h->g1_policy(); |
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734 |
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735 // Make sure that the concurrent mark thread looks to still be in |
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736 // the current cycle. |
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737 guarantee(cmThread()->during_cycle(), "invariant"); |
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738 |
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739 // We are finishing up the current cycle by clearing the next |
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740 // marking bitmap and getting it ready for the next cycle. During |
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741 // this time no other cycle can start. So, let's make sure that this |
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742 // is the case. |
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743 guarantee(!g1h->mark_in_progress(), "invariant"); |
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744 |
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745 // clear the mark bitmap (no grey objects to start with). |
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746 // We need to do this in chunks and offer to yield in between |
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747 // each chunk. |
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748 HeapWord* start = _nextMarkBitMap->startWord(); |
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749 HeapWord* end = _nextMarkBitMap->endWord(); |
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750 HeapWord* cur = start; |
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751 size_t chunkSize = M; |
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752 while (cur < end) { |
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753 HeapWord* next = cur + chunkSize; |
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754 if (next > end) |
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755 next = end; |
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756 MemRegion mr(cur,next); |
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757 _nextMarkBitMap->clearRange(mr); |
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758 cur = next; |
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759 do_yield_check(); |
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760 |
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761 // Repeat the asserts from above. We'll do them as asserts here to |
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762 // minimize their overhead on the product. However, we'll have |
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763 // them as guarantees at the beginning / end of the bitmap |
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764 // clearing to get some checking in the product. |
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765 assert(cmThread()->during_cycle(), "invariant"); |
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766 assert(!g1h->mark_in_progress(), "invariant"); |
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767 } |
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768 |
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769 // Repeat the asserts from above. |
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770 guarantee(cmThread()->during_cycle(), "invariant"); |
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771 guarantee(!g1h->mark_in_progress(), "invariant"); |
| 342 | 772 } |
| 773 | |
| 774 class NoteStartOfMarkHRClosure: public HeapRegionClosure { | |
| 775 public: | |
| 776 bool doHeapRegion(HeapRegion* r) { | |
| 777 if (!r->continuesHumongous()) { | |
| 778 r->note_start_of_marking(true); | |
| 779 } | |
| 780 return false; | |
| 781 } | |
| 782 }; | |
| 783 | |
| 784 void ConcurrentMark::checkpointRootsInitialPre() { | |
| 785 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 786 G1CollectorPolicy* g1p = g1h->g1_policy(); | |
| 787 | |
| 788 _has_aborted = false; | |
| 789 | |
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790 #ifndef PRODUCT |
| 1044 | 791 if (G1PrintReachableAtInitialMark) { |
| 1388 | 792 print_reachable("at-cycle-start", |
| 793 true /* use_prev_marking */, true /* all */); | |
| 1044 | 794 } |
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795 #endif |
| 342 | 796 |
| 797 // Initialise marking structures. This has to be done in a STW phase. | |
| 798 reset(); | |
| 799 } | |
| 800 | |
| 801 class CMMarkRootsClosure: public OopsInGenClosure { | |
| 802 private: | |
| 803 ConcurrentMark* _cm; | |
| 804 G1CollectedHeap* _g1h; | |
| 805 bool _do_barrier; | |
| 806 | |
| 807 public: | |
| 808 CMMarkRootsClosure(ConcurrentMark* cm, | |
| 809 G1CollectedHeap* g1h, | |
| 810 bool do_barrier) : _cm(cm), _g1h(g1h), | |
| 811 _do_barrier(do_barrier) { } | |
| 812 | |
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813 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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814 virtual void do_oop( oop* p) { do_oop_work(p); } |
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815 |
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816 template <class T> void do_oop_work(T* p) { |
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817 T heap_oop = oopDesc::load_heap_oop(p); |
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818 if (!oopDesc::is_null(heap_oop)) { |
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819 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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820 assert(obj->is_oop() || obj->mark() == NULL, |
| 342 | 821 "expected an oop, possibly with mark word displaced"); |
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822 HeapWord* addr = (HeapWord*)obj; |
| 342 | 823 if (_g1h->is_in_g1_reserved(addr)) { |
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824 _cm->grayRoot(obj); |
| 342 | 825 } |
| 826 } | |
| 827 if (_do_barrier) { | |
| 828 assert(!_g1h->is_in_g1_reserved(p), | |
| 829 "Should be called on external roots"); | |
| 830 do_barrier(p); | |
| 831 } | |
| 832 } | |
| 833 }; | |
| 834 | |
| 835 void ConcurrentMark::checkpointRootsInitialPost() { | |
| 836 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 837 | |
| 838 // For each region note start of marking. | |
| 839 NoteStartOfMarkHRClosure startcl; | |
| 840 g1h->heap_region_iterate(&startcl); | |
| 841 | |
| 842 // Start weak-reference discovery. | |
| 843 ReferenceProcessor* rp = g1h->ref_processor(); | |
| 844 rp->verify_no_references_recorded(); | |
| 845 rp->enable_discovery(); // enable ("weak") refs discovery | |
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846 rp->setup_policy(false); // snapshot the soft ref policy to be used in this cycle |
| 342 | 847 |
| 848 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
|
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849 // This is the start of the marking cycle, we're expected all |
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850 // threads to have SATB queues with active set to false. |
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851 satb_mq_set.set_active_all_threads(true, /* new active value */ |
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852 false /* expected_active */); |
| 342 | 853 |
| 854 // update_g1_committed() will be called at the end of an evac pause | |
| 855 // when marking is on. So, it's also called at the end of the | |
| 856 // initial-mark pause to update the heap end, if the heap expands | |
| 857 // during it. No need to call it here. | |
| 858 } | |
| 859 | |
| 860 // Checkpoint the roots into this generation from outside | |
| 861 // this generation. [Note this initial checkpoint need only | |
| 862 // be approximate -- we'll do a catch up phase subsequently.] | |
| 863 void ConcurrentMark::checkpointRootsInitial() { | |
| 864 assert(SafepointSynchronize::is_at_safepoint(), "world should be stopped"); | |
| 865 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 866 | |
| 867 double start = os::elapsedTime(); | |
| 868 | |
| 869 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); | |
| 870 g1p->record_concurrent_mark_init_start(); | |
| 871 checkpointRootsInitialPre(); | |
| 872 | |
| 873 // YSR: when concurrent precleaning is in place, we'll | |
| 874 // need to clear the cached card table here | |
| 875 | |
| 876 ResourceMark rm; | |
| 877 HandleMark hm; | |
| 878 | |
| 879 g1h->ensure_parsability(false); | |
| 880 g1h->perm_gen()->save_marks(); | |
| 881 | |
| 882 CMMarkRootsClosure notOlder(this, g1h, false); | |
| 883 CMMarkRootsClosure older(this, g1h, true); | |
| 884 | |
| 885 g1h->set_marking_started(); | |
| 886 g1h->rem_set()->prepare_for_younger_refs_iterate(false); | |
| 887 | |
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888 g1h->process_strong_roots(true, // activate StrongRootsScope |
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889 false, // fake perm gen collection |
| 342 | 890 SharedHeap::SO_AllClasses, |
| 891 ¬Older, // Regular roots | |
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892 NULL, // do not visit active blobs |
| 342 | 893 &older // Perm Gen Roots |
| 894 ); | |
| 895 checkpointRootsInitialPost(); | |
| 896 | |
| 897 // Statistics. | |
| 898 double end = os::elapsedTime(); | |
| 899 _init_times.add((end - start) * 1000.0); | |
| 900 | |
| 901 g1p->record_concurrent_mark_init_end(); | |
| 902 } | |
| 903 | |
| 904 /* | |
| 905 Notice that in the next two methods, we actually leave the STS | |
| 906 during the barrier sync and join it immediately afterwards. If we | |
| 907 do not do this, this then the following deadlock can occur: one | |
| 908 thread could be in the barrier sync code, waiting for the other | |
| 909 thread to also sync up, whereas another one could be trying to | |
| 910 yield, while also waiting for the other threads to sync up too. | |
| 911 | |
| 912 Because the thread that does the sync barrier has left the STS, it | |
| 913 is possible to be suspended for a Full GC or an evacuation pause | |
| 914 could occur. This is actually safe, since the entering the sync | |
| 915 barrier is one of the last things do_marking_step() does, and it | |
| 916 doesn't manipulate any data structures afterwards. | |
| 917 */ | |
| 918 | |
| 919 void ConcurrentMark::enter_first_sync_barrier(int task_num) { | |
| 920 if (verbose_low()) | |
| 921 gclog_or_tty->print_cr("[%d] entering first barrier", task_num); | |
| 922 | |
| 923 ConcurrentGCThread::stsLeave(); | |
| 924 _first_overflow_barrier_sync.enter(); | |
| 925 ConcurrentGCThread::stsJoin(); | |
| 926 // at this point everyone should have synced up and not be doing any | |
| 927 // more work | |
| 928 | |
| 929 if (verbose_low()) | |
| 930 gclog_or_tty->print_cr("[%d] leaving first barrier", task_num); | |
| 931 | |
| 932 // let task 0 do this | |
| 933 if (task_num == 0) { | |
| 934 // task 0 is responsible for clearing the global data structures | |
| 935 clear_marking_state(); | |
| 936 | |
| 937 if (PrintGC) { | |
| 938 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 939 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 940 gclog_or_tty->print_cr("[GC concurrent-mark-reset-for-overflow]"); | |
| 941 } | |
| 942 } | |
| 943 | |
| 944 // after this, each task should reset its own data structures then | |
| 945 // then go into the second barrier | |
| 946 } | |
| 947 | |
| 948 void ConcurrentMark::enter_second_sync_barrier(int task_num) { | |
| 949 if (verbose_low()) | |
| 950 gclog_or_tty->print_cr("[%d] entering second barrier", task_num); | |
| 951 | |
| 952 ConcurrentGCThread::stsLeave(); | |
| 953 _second_overflow_barrier_sync.enter(); | |
| 954 ConcurrentGCThread::stsJoin(); | |
| 955 // at this point everything should be re-initialised and ready to go | |
| 956 | |
| 957 if (verbose_low()) | |
| 958 gclog_or_tty->print_cr("[%d] leaving second barrier", task_num); | |
| 959 } | |
| 960 | |
| 961 void ConcurrentMark::grayRoot(oop p) { | |
| 962 HeapWord* addr = (HeapWord*) p; | |
| 963 // We can't really check against _heap_start and _heap_end, since it | |
| 964 // is possible during an evacuation pause with piggy-backed | |
| 965 // initial-mark that the committed space is expanded during the | |
| 966 // pause without CM observing this change. So the assertions below | |
| 967 // is a bit conservative; but better than nothing. | |
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968 assert(_g1h->g1_committed().contains(addr), |
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969 "address should be within the heap bounds"); |
| 342 | 970 |
| 971 if (!_nextMarkBitMap->isMarked(addr)) | |
| 972 _nextMarkBitMap->parMark(addr); | |
| 973 } | |
| 974 | |
| 975 void ConcurrentMark::grayRegionIfNecessary(MemRegion mr) { | |
| 976 // The objects on the region have already been marked "in bulk" by | |
| 977 // the caller. We only need to decide whether to push the region on | |
| 978 // the region stack or not. | |
| 979 | |
| 980 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 981 // We're done with marking and waiting for remark. We do not need to | |
| 982 // push anything else on the region stack. | |
| 983 return; | |
| 984 | |
| 985 HeapWord* finger = _finger; | |
| 986 | |
| 987 if (verbose_low()) | |
| 988 gclog_or_tty->print_cr("[global] attempting to push " | |
| 989 "region ["PTR_FORMAT", "PTR_FORMAT"), finger is at " | |
| 990 PTR_FORMAT, mr.start(), mr.end(), finger); | |
| 991 | |
| 992 if (mr.start() < finger) { | |
| 993 // The finger is always heap region aligned and it is not possible | |
| 994 // for mr to span heap regions. | |
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995 assert(mr.end() <= finger, "invariant"); |
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996 |
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997 // Separated the asserts so that we know which one fires. |
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998 assert(mr.start() <= mr.end(), |
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999 "region boundaries should fall within the committed space"); |
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1000 assert(_heap_start <= mr.start(), |
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1001 "region boundaries should fall within the committed space"); |
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1002 assert(mr.end() <= _heap_end, |
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1003 "region boundaries should fall within the committed space"); |
| 342 | 1004 if (verbose_low()) |
| 1005 gclog_or_tty->print_cr("[global] region ["PTR_FORMAT", "PTR_FORMAT") " | |
| 1006 "below the finger, pushing it", | |
| 1007 mr.start(), mr.end()); | |
| 1008 | |
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1009 if (!region_stack_push_lock_free(mr)) { |
| 342 | 1010 if (verbose_low()) |
| 1011 gclog_or_tty->print_cr("[global] region stack has overflown."); | |
| 1012 } | |
| 1013 } | |
| 1014 } | |
| 1015 | |
| 1016 void ConcurrentMark::markAndGrayObjectIfNecessary(oop p) { | |
| 1017 // The object is not marked by the caller. We need to at least mark | |
| 1018 // it and maybe push in on the stack. | |
| 1019 | |
| 1020 HeapWord* addr = (HeapWord*)p; | |
| 1021 if (!_nextMarkBitMap->isMarked(addr)) { | |
| 1022 // We definitely need to mark it, irrespective whether we bail out | |
| 1023 // because we're done with marking. | |
| 1024 if (_nextMarkBitMap->parMark(addr)) { | |
| 1025 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 1026 // If we're done with concurrent marking and we're waiting for | |
| 1027 // remark, then we're not pushing anything on the stack. | |
| 1028 return; | |
| 1029 | |
| 1030 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 1031 // CAS done in parMark(addr) above | |
| 1032 HeapWord* finger = _finger; | |
| 1033 | |
| 1034 if (addr < finger) { | |
| 1035 if (!mark_stack_push(oop(addr))) { | |
| 1036 if (verbose_low()) | |
| 1037 gclog_or_tty->print_cr("[global] global stack overflow " | |
| 1038 "during parMark"); | |
| 1039 } | |
| 1040 } | |
| 1041 } | |
| 1042 } | |
| 1043 } | |
| 1044 | |
| 1045 class CMConcurrentMarkingTask: public AbstractGangTask { | |
| 1046 private: | |
| 1047 ConcurrentMark* _cm; | |
| 1048 ConcurrentMarkThread* _cmt; | |
| 1049 | |
| 1050 public: | |
| 1051 void work(int worker_i) { | |
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1052 assert(Thread::current()->is_ConcurrentGC_thread(), |
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1053 "this should only be done by a conc GC thread"); |
| 342 | 1054 |
| 1055 double start_vtime = os::elapsedVTime(); | |
| 1056 | |
| 1057 ConcurrentGCThread::stsJoin(); | |
| 1058 | |
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1059 assert((size_t) worker_i < _cm->active_tasks(), "invariant"); |
| 342 | 1060 CMTask* the_task = _cm->task(worker_i); |
| 1061 the_task->record_start_time(); | |
| 1062 if (!_cm->has_aborted()) { | |
| 1063 do { | |
| 1064 double start_vtime_sec = os::elapsedVTime(); | |
| 1065 double start_time_sec = os::elapsedTime(); | |
| 1066 the_task->do_marking_step(10.0); | |
| 1067 double end_time_sec = os::elapsedTime(); | |
| 1068 double end_vtime_sec = os::elapsedVTime(); | |
| 1069 double elapsed_vtime_sec = end_vtime_sec - start_vtime_sec; | |
| 1070 double elapsed_time_sec = end_time_sec - start_time_sec; | |
| 1071 _cm->clear_has_overflown(); | |
| 1072 | |
| 1073 bool ret = _cm->do_yield_check(worker_i); | |
| 1074 | |
| 1075 jlong sleep_time_ms; | |
| 1076 if (!_cm->has_aborted() && the_task->has_aborted()) { | |
| 1077 sleep_time_ms = | |
| 1078 (jlong) (elapsed_vtime_sec * _cm->sleep_factor() * 1000.0); | |
| 1079 ConcurrentGCThread::stsLeave(); | |
| 1080 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1081 ConcurrentGCThread::stsJoin(); | |
| 1082 } | |
| 1083 double end_time2_sec = os::elapsedTime(); | |
| 1084 double elapsed_time2_sec = end_time2_sec - start_time_sec; | |
| 1085 | |
| 1086 #if 0 | |
| 1087 gclog_or_tty->print_cr("CM: elapsed %1.4lf ms, sleep %1.4lf ms, " | |
| 1088 "overhead %1.4lf", | |
| 1089 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms, | |
| 1090 the_task->conc_overhead(os::elapsedTime()) * 8.0); | |
| 1091 gclog_or_tty->print_cr("elapsed time %1.4lf ms, time 2: %1.4lf ms", | |
| 1092 elapsed_time_sec * 1000.0, elapsed_time2_sec * 1000.0); | |
| 1093 #endif | |
| 1094 } while (!_cm->has_aborted() && the_task->has_aborted()); | |
| 1095 } | |
| 1096 the_task->record_end_time(); | |
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1097 guarantee(!the_task->has_aborted() || _cm->has_aborted(), "invariant"); |
| 342 | 1098 |
| 1099 ConcurrentGCThread::stsLeave(); | |
| 1100 | |
| 1101 double end_vtime = os::elapsedVTime(); | |
| 1102 _cm->update_accum_task_vtime(worker_i, end_vtime - start_vtime); | |
| 1103 } | |
| 1104 | |
| 1105 CMConcurrentMarkingTask(ConcurrentMark* cm, | |
| 1106 ConcurrentMarkThread* cmt) : | |
| 1107 AbstractGangTask("Concurrent Mark"), _cm(cm), _cmt(cmt) { } | |
| 1108 | |
| 1109 ~CMConcurrentMarkingTask() { } | |
| 1110 }; | |
| 1111 | |
| 1112 void ConcurrentMark::markFromRoots() { | |
| 1113 // we might be tempted to assert that: | |
| 1114 // assert(asynch == !SafepointSynchronize::is_at_safepoint(), | |
| 1115 // "inconsistent argument?"); | |
| 1116 // However that wouldn't be right, because it's possible that | |
| 1117 // a safepoint is indeed in progress as a younger generation | |
| 1118 // stop-the-world GC happens even as we mark in this generation. | |
| 1119 | |
| 1120 _restart_for_overflow = false; | |
| 1121 | |
| 1122 set_phase(MAX2((size_t) 1, parallel_marking_threads()), true); | |
| 1123 | |
| 1124 CMConcurrentMarkingTask markingTask(this, cmThread()); | |
| 1125 if (parallel_marking_threads() > 0) | |
| 1126 _parallel_workers->run_task(&markingTask); | |
| 1127 else | |
| 1128 markingTask.work(0); | |
| 1129 print_stats(); | |
| 1130 } | |
| 1131 | |
| 1132 void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) { | |
| 1133 // world is stopped at this checkpoint | |
| 1134 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1135 "world should be stopped"); | |
| 1136 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1137 | |
| 1138 // If a full collection has happened, we shouldn't do this. | |
| 1139 if (has_aborted()) { | |
| 1140 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1141 return; | |
| 1142 } | |
| 1143 | |
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1144 if (VerifyDuringGC) { |
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1145 HandleMark hm; // handle scope |
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1146 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1147 Universe::heap()->prepare_for_verify(); |
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1148 Universe::verify(true, false, true); |
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1149 } |
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1150 |
| 342 | 1151 G1CollectorPolicy* g1p = g1h->g1_policy(); |
| 1152 g1p->record_concurrent_mark_remark_start(); | |
| 1153 | |
| 1154 double start = os::elapsedTime(); | |
| 1155 | |
| 1156 checkpointRootsFinalWork(); | |
| 1157 | |
| 1158 double mark_work_end = os::elapsedTime(); | |
| 1159 | |
| 1160 weakRefsWork(clear_all_soft_refs); | |
| 1161 | |
| 1162 if (has_overflown()) { | |
| 1163 // Oops. We overflowed. Restart concurrent marking. | |
| 1164 _restart_for_overflow = true; | |
| 1165 // Clear the flag. We do not need it any more. | |
| 1166 clear_has_overflown(); | |
| 1167 if (G1TraceMarkStackOverflow) | |
| 1168 gclog_or_tty->print_cr("\nRemark led to restart for overflow."); | |
| 1169 } else { | |
| 1170 // We're done with marking. | |
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1171 // This is the end of the marking cycle, we're expected all |
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1172 // threads to have SATB queues with active set to true. |
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1173 JavaThread::satb_mark_queue_set().set_active_all_threads( |
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1174 false, /* new active value */ |
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1175 true /* expected_active */); |
| 811 | 1176 |
| 1177 if (VerifyDuringGC) { | |
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1178 HandleMark hm; // handle scope |
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1179 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1180 Universe::heap()->prepare_for_verify(); |
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1181 Universe::heap()->verify(/* allow_dirty */ true, |
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1182 /* silent */ false, |
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1183 /* use_prev_marking */ false); |
| 811 | 1184 } |
| 342 | 1185 } |
| 1186 | |
| 1187 #if VERIFY_OBJS_PROCESSED | |
| 1188 _scan_obj_cl.objs_processed = 0; | |
| 1189 ThreadLocalObjQueue::objs_enqueued = 0; | |
| 1190 #endif | |
| 1191 | |
| 1192 // Statistics | |
| 1193 double now = os::elapsedTime(); | |
| 1194 _remark_mark_times.add((mark_work_end - start) * 1000.0); | |
| 1195 _remark_weak_ref_times.add((now - mark_work_end) * 1000.0); | |
| 1196 _remark_times.add((now - start) * 1000.0); | |
| 1197 | |
| 1198 g1p->record_concurrent_mark_remark_end(); | |
| 1199 } | |
| 1200 | |
| 1201 | |
| 1202 #define CARD_BM_TEST_MODE 0 | |
| 1203 | |
| 1204 class CalcLiveObjectsClosure: public HeapRegionClosure { | |
| 1205 | |
| 1206 CMBitMapRO* _bm; | |
| 1207 ConcurrentMark* _cm; | |
| 1208 bool _changed; | |
| 1209 bool _yield; | |
| 1210 size_t _words_done; | |
| 1211 size_t _tot_live; | |
| 1212 size_t _tot_used; | |
| 1213 size_t _regions_done; | |
| 1214 double _start_vtime_sec; | |
| 1215 | |
| 1216 BitMap* _region_bm; | |
| 1217 BitMap* _card_bm; | |
| 1218 intptr_t _bottom_card_num; | |
| 1219 bool _final; | |
| 1220 | |
| 1221 void mark_card_num_range(intptr_t start_card_num, intptr_t last_card_num) { | |
| 1222 for (intptr_t i = start_card_num; i <= last_card_num; i++) { | |
| 1223 #if CARD_BM_TEST_MODE | |
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1224 guarantee(_card_bm->at(i - _bottom_card_num), "Should already be set."); |
| 342 | 1225 #else |
| 1226 _card_bm->par_at_put(i - _bottom_card_num, 1); | |
| 1227 #endif | |
| 1228 } | |
| 1229 } | |
| 1230 | |
| 1231 public: | |
| 1232 CalcLiveObjectsClosure(bool final, | |
| 1233 CMBitMapRO *bm, ConcurrentMark *cm, | |
| 936 | 1234 BitMap* region_bm, BitMap* card_bm) : |
| 342 | 1235 _bm(bm), _cm(cm), _changed(false), _yield(true), |
| 1236 _words_done(0), _tot_live(0), _tot_used(0), | |
| 936 | 1237 _region_bm(region_bm), _card_bm(card_bm),_final(final), |
| 342 | 1238 _regions_done(0), _start_vtime_sec(0.0) |
| 1239 { | |
| 1240 _bottom_card_num = | |
| 1241 intptr_t(uintptr_t(G1CollectedHeap::heap()->reserved_region().start()) >> | |
| 1242 CardTableModRefBS::card_shift); | |
| 1243 } | |
| 1244 | |
| 829 | 1245 // It takes a region that's not empty (i.e., it has at least one |
| 1246 // live object in it and sets its corresponding bit on the region | |
| 1247 // bitmap to 1. If the region is "starts humongous" it will also set | |
| 1248 // to 1 the bits on the region bitmap that correspond to its | |
| 1249 // associated "continues humongous" regions. | |
| 1250 void set_bit_for_region(HeapRegion* hr) { | |
| 1251 assert(!hr->continuesHumongous(), "should have filtered those out"); | |
| 1252 | |
| 1253 size_t index = hr->hrs_index(); | |
| 1254 if (!hr->startsHumongous()) { | |
| 1255 // Normal (non-humongous) case: just set the bit. | |
| 1256 _region_bm->par_at_put((BitMap::idx_t) index, true); | |
| 1257 } else { | |
| 1258 // Starts humongous case: calculate how many regions are part of | |
| 1259 // this humongous region and then set the bit range. It might | |
| 1260 // have been a bit more efficient to look at the object that | |
| 1261 // spans these humongous regions to calculate their number from | |
| 1262 // the object's size. However, it's a good idea to calculate | |
| 1263 // this based on the metadata itself, and not the region | |
| 1264 // contents, so that this code is not aware of what goes into | |
| 1265 // the humongous regions (in case this changes in the future). | |
| 1266 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1267 size_t end_index = index + 1; | |
| 831 | 1268 while (end_index < g1h->n_regions()) { |
| 1269 HeapRegion* chr = g1h->region_at(end_index); | |
| 829 | 1270 if (!chr->continuesHumongous()) { |
| 1271 break; | |
| 1272 } | |
| 1273 end_index += 1; | |
| 1274 } | |
| 1275 _region_bm->par_at_put_range((BitMap::idx_t) index, | |
| 1276 (BitMap::idx_t) end_index, true); | |
| 1277 } | |
| 1278 } | |
| 1279 | |
| 342 | 1280 bool doHeapRegion(HeapRegion* hr) { |
| 1281 if (!_final && _regions_done == 0) | |
| 1282 _start_vtime_sec = os::elapsedVTime(); | |
| 1283 | |
| 639 | 1284 if (hr->continuesHumongous()) { |
| 829 | 1285 // We will ignore these here and process them when their |
| 1286 // associated "starts humongous" region is processed (see | |
| 1287 // set_bit_for_heap_region()). Note that we cannot rely on their | |
| 1288 // associated "starts humongous" region to have their bit set to | |
| 1289 // 1 since, due to the region chunking in the parallel region | |
| 1290 // iteration, a "continues humongous" region might be visited | |
| 1291 // before its associated "starts humongous". | |
| 639 | 1292 return false; |
| 1293 } | |
| 342 | 1294 |
| 1295 HeapWord* nextTop = hr->next_top_at_mark_start(); | |
| 1296 HeapWord* start = hr->top_at_conc_mark_count(); | |
| 1297 assert(hr->bottom() <= start && start <= hr->end() && | |
| 1298 hr->bottom() <= nextTop && nextTop <= hr->end() && | |
| 1299 start <= nextTop, | |
| 1300 "Preconditions."); | |
| 1301 // Otherwise, record the number of word's we'll examine. | |
| 1302 size_t words_done = (nextTop - start); | |
| 1303 // Find the first marked object at or after "start". | |
| 1304 start = _bm->getNextMarkedWordAddress(start, nextTop); | |
| 1305 size_t marked_bytes = 0; | |
| 1306 | |
| 1307 // Below, the term "card num" means the result of shifting an address | |
| 1308 // by the card shift -- address 0 corresponds to card number 0. One | |
| 1309 // must subtract the card num of the bottom of the heap to obtain a | |
| 1310 // card table index. | |
| 1311 // The first card num of the sequence of live cards currently being | |
| 1312 // constructed. -1 ==> no sequence. | |
| 1313 intptr_t start_card_num = -1; | |
| 1314 // The last card num of the sequence of live cards currently being | |
| 1315 // constructed. -1 ==> no sequence. | |
| 1316 intptr_t last_card_num = -1; | |
| 1317 | |
| 1318 while (start < nextTop) { | |
| 1319 if (_yield && _cm->do_yield_check()) { | |
| 1320 // We yielded. It might be for a full collection, in which case | |
| 1321 // all bets are off; terminate the traversal. | |
| 1322 if (_cm->has_aborted()) { | |
| 1323 _changed = false; | |
| 1324 return true; | |
| 1325 } else { | |
| 1326 // Otherwise, it might be a collection pause, and the region | |
| 1327 // we're looking at might be in the collection set. We'll | |
| 1328 // abandon this region. | |
| 1329 return false; | |
| 1330 } | |
| 1331 } | |
| 1332 oop obj = oop(start); | |
| 1333 int obj_sz = obj->size(); | |
| 1334 // The card num of the start of the current object. | |
| 1335 intptr_t obj_card_num = | |
| 1336 intptr_t(uintptr_t(start) >> CardTableModRefBS::card_shift); | |
| 1337 | |
| 1338 HeapWord* obj_last = start + obj_sz - 1; | |
| 1339 intptr_t obj_last_card_num = | |
| 1340 intptr_t(uintptr_t(obj_last) >> CardTableModRefBS::card_shift); | |
| 1341 | |
| 1342 if (obj_card_num != last_card_num) { | |
| 1343 if (start_card_num == -1) { | |
| 1344 assert(last_card_num == -1, "Both or neither."); | |
| 1345 start_card_num = obj_card_num; | |
| 1346 } else { | |
| 1347 assert(last_card_num != -1, "Both or neither."); | |
| 1348 assert(obj_card_num >= last_card_num, "Inv"); | |
| 1349 if ((obj_card_num - last_card_num) > 1) { | |
| 1350 // Mark the last run, and start a new one. | |
| 1351 mark_card_num_range(start_card_num, last_card_num); | |
| 1352 start_card_num = obj_card_num; | |
| 1353 } | |
| 1354 } | |
| 1355 #if CARD_BM_TEST_MODE | |
| 1356 /* | |
| 1357 gclog_or_tty->print_cr("Setting bits from %d/%d.", | |
| 1358 obj_card_num - _bottom_card_num, | |
| 1359 obj_last_card_num - _bottom_card_num); | |
| 1360 */ | |
| 1361 for (intptr_t j = obj_card_num; j <= obj_last_card_num; j++) { | |
| 1362 _card_bm->par_at_put(j - _bottom_card_num, 1); | |
| 1363 } | |
| 1364 #endif | |
| 1365 } | |
| 1366 // In any case, we set the last card num. | |
| 1367 last_card_num = obj_last_card_num; | |
| 1368 | |
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1369 marked_bytes += (size_t)obj_sz * HeapWordSize; |
| 342 | 1370 // Find the next marked object after this one. |
| 1371 start = _bm->getNextMarkedWordAddress(start + 1, nextTop); | |
| 1372 _changed = true; | |
| 1373 } | |
| 1374 // Handle the last range, if any. | |
| 1375 if (start_card_num != -1) | |
| 1376 mark_card_num_range(start_card_num, last_card_num); | |
| 1377 if (_final) { | |
| 1378 // Mark the allocated-since-marking portion... | |
| 1379 HeapWord* tp = hr->top(); | |
| 1380 if (nextTop < tp) { | |
| 1381 start_card_num = | |
| 1382 intptr_t(uintptr_t(nextTop) >> CardTableModRefBS::card_shift); | |
| 1383 last_card_num = | |
| 1384 intptr_t(uintptr_t(tp) >> CardTableModRefBS::card_shift); | |
| 1385 mark_card_num_range(start_card_num, last_card_num); | |
| 1386 // This definitely means the region has live objects. | |
| 829 | 1387 set_bit_for_region(hr); |
| 342 | 1388 } |
| 1389 } | |
| 1390 | |
| 1391 hr->add_to_marked_bytes(marked_bytes); | |
| 1392 // Update the live region bitmap. | |
| 1393 if (marked_bytes > 0) { | |
| 829 | 1394 set_bit_for_region(hr); |
| 342 | 1395 } |
| 1396 hr->set_top_at_conc_mark_count(nextTop); | |
| 1397 _tot_live += hr->next_live_bytes(); | |
| 1398 _tot_used += hr->used(); | |
| 1399 _words_done = words_done; | |
| 1400 | |
| 1401 if (!_final) { | |
| 1402 ++_regions_done; | |
| 1403 if (_regions_done % 10 == 0) { | |
| 1404 double end_vtime_sec = os::elapsedVTime(); | |
| 1405 double elapsed_vtime_sec = end_vtime_sec - _start_vtime_sec; | |
| 1406 if (elapsed_vtime_sec > (10.0 / 1000.0)) { | |
| 1407 jlong sleep_time_ms = | |
| 1408 (jlong) (elapsed_vtime_sec * _cm->cleanup_sleep_factor() * 1000.0); | |
| 1409 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1410 _start_vtime_sec = end_vtime_sec; | |
| 1411 } | |
| 1412 } | |
| 1413 } | |
| 1414 | |
| 1415 return false; | |
| 1416 } | |
| 1417 | |
| 1418 bool changed() { return _changed; } | |
| 1419 void reset() { _changed = false; _words_done = 0; } | |
| 1420 void no_yield() { _yield = false; } | |
| 1421 size_t words_done() { return _words_done; } | |
| 1422 size_t tot_live() { return _tot_live; } | |
| 1423 size_t tot_used() { return _tot_used; } | |
| 1424 }; | |
| 1425 | |
| 1426 | |
| 1427 void ConcurrentMark::calcDesiredRegions() { | |
| 1428 _region_bm.clear(); | |
| 1429 _card_bm.clear(); | |
| 1430 CalcLiveObjectsClosure calccl(false /*final*/, | |
| 1431 nextMarkBitMap(), this, | |
| 936 | 1432 &_region_bm, &_card_bm); |
| 342 | 1433 G1CollectedHeap *g1h = G1CollectedHeap::heap(); |
| 1434 g1h->heap_region_iterate(&calccl); | |
| 1435 | |
| 1436 do { | |
| 1437 calccl.reset(); | |
| 1438 g1h->heap_region_iterate(&calccl); | |
| 1439 } while (calccl.changed()); | |
| 1440 } | |
| 1441 | |
| 1442 class G1ParFinalCountTask: public AbstractGangTask { | |
| 1443 protected: | |
| 1444 G1CollectedHeap* _g1h; | |
| 1445 CMBitMap* _bm; | |
| 1446 size_t _n_workers; | |
| 1447 size_t *_live_bytes; | |
| 1448 size_t *_used_bytes; | |
| 1449 BitMap* _region_bm; | |
| 1450 BitMap* _card_bm; | |
| 1451 public: | |
| 1452 G1ParFinalCountTask(G1CollectedHeap* g1h, CMBitMap* bm, | |
| 1453 BitMap* region_bm, BitMap* card_bm) : | |
| 1454 AbstractGangTask("G1 final counting"), _g1h(g1h), | |
| 1455 _bm(bm), _region_bm(region_bm), _card_bm(card_bm) | |
| 1456 { | |
| 1457 if (ParallelGCThreads > 0) | |
| 1458 _n_workers = _g1h->workers()->total_workers(); | |
| 1459 else | |
| 1460 _n_workers = 1; | |
| 1461 _live_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1462 _used_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1463 } | |
| 1464 | |
| 1465 ~G1ParFinalCountTask() { | |
| 1466 FREE_C_HEAP_ARRAY(size_t, _live_bytes); | |
| 1467 FREE_C_HEAP_ARRAY(size_t, _used_bytes); | |
| 1468 } | |
| 1469 | |
| 1470 void work(int i) { | |
| 1471 CalcLiveObjectsClosure calccl(true /*final*/, | |
| 1472 _bm, _g1h->concurrent_mark(), | |
| 936 | 1473 _region_bm, _card_bm); |
| 342 | 1474 calccl.no_yield(); |
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1475 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1476 _g1h->heap_region_par_iterate_chunked(&calccl, i, |
| 1477 HeapRegion::FinalCountClaimValue); | |
| 342 | 1478 } else { |
| 1479 _g1h->heap_region_iterate(&calccl); | |
| 1480 } | |
| 1481 assert(calccl.complete(), "Shouldn't have yielded!"); | |
| 1482 | |
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1483 assert((size_t) i < _n_workers, "invariant"); |
| 342 | 1484 _live_bytes[i] = calccl.tot_live(); |
| 1485 _used_bytes[i] = calccl.tot_used(); | |
| 1486 } | |
| 1487 size_t live_bytes() { | |
| 1488 size_t live_bytes = 0; | |
| 1489 for (size_t i = 0; i < _n_workers; ++i) | |
| 1490 live_bytes += _live_bytes[i]; | |
| 1491 return live_bytes; | |
| 1492 } | |
| 1493 size_t used_bytes() { | |
| 1494 size_t used_bytes = 0; | |
| 1495 for (size_t i = 0; i < _n_workers; ++i) | |
| 1496 used_bytes += _used_bytes[i]; | |
| 1497 return used_bytes; | |
| 1498 } | |
| 1499 }; | |
| 1500 | |
| 1501 class G1ParNoteEndTask; | |
| 1502 | |
| 1503 class G1NoteEndOfConcMarkClosure : public HeapRegionClosure { | |
| 1504 G1CollectedHeap* _g1; | |
| 1505 int _worker_num; | |
| 1506 size_t _max_live_bytes; | |
| 1507 size_t _regions_claimed; | |
| 1508 size_t _freed_bytes; | |
| 1509 size_t _cleared_h_regions; | |
| 1510 size_t _freed_regions; | |
| 1511 UncleanRegionList* _unclean_region_list; | |
| 1512 double _claimed_region_time; | |
| 1513 double _max_region_time; | |
| 1514 | |
| 1515 public: | |
| 1516 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1517 UncleanRegionList* list, | |
| 1518 int worker_num); | |
| 1519 size_t freed_bytes() { return _freed_bytes; } | |
| 1520 size_t cleared_h_regions() { return _cleared_h_regions; } | |
| 1521 size_t freed_regions() { return _freed_regions; } | |
| 1522 UncleanRegionList* unclean_region_list() { | |
| 1523 return _unclean_region_list; | |
| 1524 } | |
| 1525 | |
| 1526 bool doHeapRegion(HeapRegion *r); | |
| 1527 | |
| 1528 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1529 size_t regions_claimed() { return _regions_claimed; } | |
| 1530 double claimed_region_time_sec() { return _claimed_region_time; } | |
| 1531 double max_region_time_sec() { return _max_region_time; } | |
| 1532 }; | |
| 1533 | |
| 1534 class G1ParNoteEndTask: public AbstractGangTask { | |
| 1535 friend class G1NoteEndOfConcMarkClosure; | |
| 1536 protected: | |
| 1537 G1CollectedHeap* _g1h; | |
| 1538 size_t _max_live_bytes; | |
| 1539 size_t _freed_bytes; | |
| 1540 ConcurrentMark::ParCleanupThreadState** _par_cleanup_thread_state; | |
| 1541 public: | |
| 1542 G1ParNoteEndTask(G1CollectedHeap* g1h, | |
| 1543 ConcurrentMark::ParCleanupThreadState** | |
| 1544 par_cleanup_thread_state) : | |
| 1545 AbstractGangTask("G1 note end"), _g1h(g1h), | |
| 1546 _max_live_bytes(0), _freed_bytes(0), | |
| 1547 _par_cleanup_thread_state(par_cleanup_thread_state) | |
| 1548 {} | |
| 1549 | |
| 1550 void work(int i) { | |
| 1551 double start = os::elapsedTime(); | |
| 1552 G1NoteEndOfConcMarkClosure g1_note_end(_g1h, | |
| 1553 &_par_cleanup_thread_state[i]->list, | |
| 1554 i); | |
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1555 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1556 _g1h->heap_region_par_iterate_chunked(&g1_note_end, i, |
| 1557 HeapRegion::NoteEndClaimValue); | |
| 342 | 1558 } else { |
| 1559 _g1h->heap_region_iterate(&g1_note_end); | |
| 1560 } | |
| 1561 assert(g1_note_end.complete(), "Shouldn't have yielded!"); | |
| 1562 | |
| 1563 // Now finish up freeing the current thread's regions. | |
| 1564 _g1h->finish_free_region_work(g1_note_end.freed_bytes(), | |
| 1565 g1_note_end.cleared_h_regions(), | |
| 1566 0, NULL); | |
| 1567 { | |
| 1568 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 1569 _max_live_bytes += g1_note_end.max_live_bytes(); | |
| 1570 _freed_bytes += g1_note_end.freed_bytes(); | |
| 1571 } | |
| 1572 double end = os::elapsedTime(); | |
| 1573 if (G1PrintParCleanupStats) { | |
| 1574 gclog_or_tty->print(" Worker thread %d [%8.3f..%8.3f = %8.3f ms] " | |
| 1575 "claimed %d regions (tot = %8.3f ms, max = %8.3f ms).\n", | |
| 1576 i, start, end, (end-start)*1000.0, | |
| 1577 g1_note_end.regions_claimed(), | |
| 1578 g1_note_end.claimed_region_time_sec()*1000.0, | |
| 1579 g1_note_end.max_region_time_sec()*1000.0); | |
| 1580 } | |
| 1581 } | |
| 1582 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1583 size_t freed_bytes() { return _freed_bytes; } | |
| 1584 }; | |
| 1585 | |
| 1586 class G1ParScrubRemSetTask: public AbstractGangTask { | |
| 1587 protected: | |
| 1588 G1RemSet* _g1rs; | |
| 1589 BitMap* _region_bm; | |
| 1590 BitMap* _card_bm; | |
| 1591 public: | |
| 1592 G1ParScrubRemSetTask(G1CollectedHeap* g1h, | |
| 1593 BitMap* region_bm, BitMap* card_bm) : | |
| 1594 AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()), | |
| 1595 _region_bm(region_bm), _card_bm(card_bm) | |
| 1596 {} | |
| 1597 | |
| 1598 void work(int i) { | |
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1599 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1600 _g1rs->scrub_par(_region_bm, _card_bm, i, |
| 1601 HeapRegion::ScrubRemSetClaimValue); | |
| 342 | 1602 } else { |
| 1603 _g1rs->scrub(_region_bm, _card_bm); | |
| 1604 } | |
| 1605 } | |
| 1606 | |
| 1607 }; | |
| 1608 | |
| 1609 G1NoteEndOfConcMarkClosure:: | |
| 1610 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1611 UncleanRegionList* list, | |
| 1612 int worker_num) | |
| 1613 : _g1(g1), _worker_num(worker_num), | |
| 1614 _max_live_bytes(0), _regions_claimed(0), | |
| 1615 _freed_bytes(0), _cleared_h_regions(0), _freed_regions(0), | |
| 1616 _claimed_region_time(0.0), _max_region_time(0.0), | |
| 1617 _unclean_region_list(list) | |
| 1618 {} | |
| 1619 | |
| 1620 bool G1NoteEndOfConcMarkClosure::doHeapRegion(HeapRegion *r) { | |
| 1621 // We use a claim value of zero here because all regions | |
| 1622 // were claimed with value 1 in the FinalCount task. | |
| 1623 r->reset_gc_time_stamp(); | |
| 1624 if (!r->continuesHumongous()) { | |
| 1625 double start = os::elapsedTime(); | |
| 1626 _regions_claimed++; | |
| 1627 r->note_end_of_marking(); | |
| 1628 _max_live_bytes += r->max_live_bytes(); | |
| 1629 _g1->free_region_if_totally_empty_work(r, | |
| 1630 _freed_bytes, | |
| 1631 _cleared_h_regions, | |
| 1632 _freed_regions, | |
| 1633 _unclean_region_list, | |
| 1634 true /*par*/); | |
| 1635 double region_time = (os::elapsedTime() - start); | |
| 1636 _claimed_region_time += region_time; | |
| 1637 if (region_time > _max_region_time) _max_region_time = region_time; | |
| 1638 } | |
| 1639 return false; | |
| 1640 } | |
| 1641 | |
| 1642 void ConcurrentMark::cleanup() { | |
| 1643 // world is stopped at this checkpoint | |
| 1644 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1645 "world should be stopped"); | |
| 1646 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1647 | |
| 1648 // If a full collection has happened, we shouldn't do this. | |
| 1649 if (has_aborted()) { | |
| 1650 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1651 return; | |
| 1652 } | |
| 1653 | |
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1654 if (VerifyDuringGC) { |
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1655 HandleMark hm; // handle scope |
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1656 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1657 Universe::heap()->prepare_for_verify(); |
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1658 Universe::verify(/* allow dirty */ true, |
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1659 /* silent */ false, |
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1660 /* prev marking */ true); |
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1661 } |
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1662 |
| 342 | 1663 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); |
| 1664 g1p->record_concurrent_mark_cleanup_start(); | |
| 1665 | |
| 1666 double start = os::elapsedTime(); | |
| 1667 | |
| 1668 // Do counting once more with the world stopped for good measure. | |
| 1669 G1ParFinalCountTask g1_par_count_task(g1h, nextMarkBitMap(), | |
| 1670 &_region_bm, &_card_bm); | |
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1671 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1672 assert(g1h->check_heap_region_claim_values( |
| 1673 HeapRegion::InitialClaimValue), | |
| 1674 "sanity check"); | |
| 1675 | |
| 342 | 1676 int n_workers = g1h->workers()->total_workers(); |
| 1677 g1h->set_par_threads(n_workers); | |
| 1678 g1h->workers()->run_task(&g1_par_count_task); | |
| 1679 g1h->set_par_threads(0); | |
| 355 | 1680 |
| 1681 assert(g1h->check_heap_region_claim_values( | |
| 1682 HeapRegion::FinalCountClaimValue), | |
| 1683 "sanity check"); | |
| 342 | 1684 } else { |
| 1685 g1_par_count_task.work(0); | |
| 1686 } | |
| 1687 | |
| 1688 size_t known_garbage_bytes = | |
| 1689 g1_par_count_task.used_bytes() - g1_par_count_task.live_bytes(); | |
| 1690 #if 0 | |
| 1691 gclog_or_tty->print_cr("used %1.2lf, live %1.2lf, garbage %1.2lf", | |
| 1692 (double) g1_par_count_task.used_bytes() / (double) (1024 * 1024), | |
| 1693 (double) g1_par_count_task.live_bytes() / (double) (1024 * 1024), | |
| 1694 (double) known_garbage_bytes / (double) (1024 * 1024)); | |
| 1695 #endif // 0 | |
| 1696 g1p->set_known_garbage_bytes(known_garbage_bytes); | |
| 1697 | |
| 1698 size_t start_used_bytes = g1h->used(); | |
| 1699 _at_least_one_mark_complete = true; | |
| 1700 g1h->set_marking_complete(); | |
| 1701 | |
| 1702 double count_end = os::elapsedTime(); | |
| 1703 double this_final_counting_time = (count_end - start); | |
| 1704 if (G1PrintParCleanupStats) { | |
| 1705 gclog_or_tty->print_cr("Cleanup:"); | |
| 1706 gclog_or_tty->print_cr(" Finalize counting: %8.3f ms", | |
| 1707 this_final_counting_time*1000.0); | |
| 1708 } | |
| 1709 _total_counting_time += this_final_counting_time; | |
| 1710 | |
| 1711 // Install newly created mark bitMap as "prev". | |
| 1712 swapMarkBitMaps(); | |
| 1713 | |
| 1714 g1h->reset_gc_time_stamp(); | |
| 1715 | |
| 1716 // Note end of marking in all heap regions. | |
| 1717 double note_end_start = os::elapsedTime(); | |
| 1718 G1ParNoteEndTask g1_par_note_end_task(g1h, _par_cleanup_thread_state); | |
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1719 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 1720 int n_workers = g1h->workers()->total_workers(); |
| 1721 g1h->set_par_threads(n_workers); | |
| 1722 g1h->workers()->run_task(&g1_par_note_end_task); | |
| 1723 g1h->set_par_threads(0); | |
| 355 | 1724 |
| 1725 assert(g1h->check_heap_region_claim_values(HeapRegion::NoteEndClaimValue), | |
| 1726 "sanity check"); | |
| 342 | 1727 } else { |
| 1728 g1_par_note_end_task.work(0); | |
| 1729 } | |
| 1730 g1h->set_unclean_regions_coming(true); | |
| 1731 double note_end_end = os::elapsedTime(); | |
| 1732 // Tell the mutators that there might be unclean regions coming... | |
| 1733 if (G1PrintParCleanupStats) { | |
| 1734 gclog_or_tty->print_cr(" note end of marking: %8.3f ms.", | |
| 1735 (note_end_end - note_end_start)*1000.0); | |
| 1736 } | |
| 1737 | |
| 355 | 1738 |
| 342 | 1739 // call below, since it affects the metric by which we sort the heap |
| 1740 // regions. | |
| 1741 if (G1ScrubRemSets) { | |
| 1742 double rs_scrub_start = os::elapsedTime(); | |
| 1743 G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm); | |
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1744 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 1745 int n_workers = g1h->workers()->total_workers(); |
| 1746 g1h->set_par_threads(n_workers); | |
| 1747 g1h->workers()->run_task(&g1_par_scrub_rs_task); | |
| 1748 g1h->set_par_threads(0); | |
| 355 | 1749 |
| 1750 assert(g1h->check_heap_region_claim_values( | |
| 1751 HeapRegion::ScrubRemSetClaimValue), | |
| 1752 "sanity check"); | |
| 342 | 1753 } else { |
| 1754 g1_par_scrub_rs_task.work(0); | |
| 1755 } | |
| 1756 | |
| 1757 double rs_scrub_end = os::elapsedTime(); | |
| 1758 double this_rs_scrub_time = (rs_scrub_end - rs_scrub_start); | |
| 1759 _total_rs_scrub_time += this_rs_scrub_time; | |
| 1760 } | |
| 1761 | |
| 1762 // this will also free any regions totally full of garbage objects, | |
| 1763 // and sort the regions. | |
| 1764 g1h->g1_policy()->record_concurrent_mark_cleanup_end( | |
| 1765 g1_par_note_end_task.freed_bytes(), | |
| 1766 g1_par_note_end_task.max_live_bytes()); | |
| 1767 | |
| 1768 // Statistics. | |
| 1769 double end = os::elapsedTime(); | |
| 1770 _cleanup_times.add((end - start) * 1000.0); | |
| 1771 | |
| 1772 // G1CollectedHeap::heap()->print(); | |
| 1773 // gclog_or_tty->print_cr("HEAP GC TIME STAMP : %d", | |
| 1774 // G1CollectedHeap::heap()->get_gc_time_stamp()); | |
| 1775 | |
| 1776 if (PrintGC || PrintGCDetails) { | |
| 1777 g1h->print_size_transition(gclog_or_tty, | |
| 1778 start_used_bytes, | |
| 1779 g1h->used(), | |
| 1780 g1h->capacity()); | |
| 1781 } | |
| 1782 | |
| 1783 size_t cleaned_up_bytes = start_used_bytes - g1h->used(); | |
| 1784 g1p->decrease_known_garbage_bytes(cleaned_up_bytes); | |
| 1785 | |
| 1786 // We need to make this be a "collection" so any collection pause that | |
| 1787 // races with it goes around and waits for completeCleanup to finish. | |
| 1788 g1h->increment_total_collections(); | |
| 1789 | |
| 751 | 1790 if (VerifyDuringGC) { |
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1791 HandleMark hm; // handle scope |
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1792 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1793 Universe::heap()->prepare_for_verify(); |
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1794 Universe::verify(/* allow dirty */ true, |
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1795 /* silent */ false, |
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1796 /* prev marking */ true); |
| 342 | 1797 } |
| 1798 } | |
| 1799 | |
| 1800 void ConcurrentMark::completeCleanup() { | |
| 1801 // A full collection intervened. | |
| 1802 if (has_aborted()) return; | |
| 1803 | |
| 1804 int first = 0; | |
| 1805 int last = (int)MAX2(ParallelGCThreads, (size_t)1); | |
| 1806 for (int t = 0; t < last; t++) { | |
| 1807 UncleanRegionList* list = &_par_cleanup_thread_state[t]->list; | |
| 1808 assert(list->well_formed(), "Inv"); | |
| 1809 HeapRegion* hd = list->hd(); | |
| 1810 while (hd != NULL) { | |
| 1811 // Now finish up the other stuff. | |
| 1812 hd->rem_set()->clear(); | |
| 1813 HeapRegion* next_hd = hd->next_from_unclean_list(); | |
| 1814 (void)list->pop(); | |
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1815 assert(list->hd() == next_hd, "how not?"); |
| 342 | 1816 _g1h->put_region_on_unclean_list(hd); |
| 1817 if (!hd->isHumongous()) { | |
| 1818 // Add this to the _free_regions count by 1. | |
| 1819 _g1h->finish_free_region_work(0, 0, 1, NULL); | |
| 1820 } | |
| 1821 hd = list->hd(); | |
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1822 assert(hd == next_hd, "how not?"); |
| 342 | 1823 } |
| 1824 } | |
| 1825 } | |
| 1826 | |
| 1827 | |
| 1828 class G1CMIsAliveClosure: public BoolObjectClosure { | |
| 1829 G1CollectedHeap* _g1; | |
| 1830 public: | |
| 1831 G1CMIsAliveClosure(G1CollectedHeap* g1) : | |
| 1832 _g1(g1) | |
| 1833 {} | |
| 1834 | |
| 1835 void do_object(oop obj) { | |
| 1836 assert(false, "not to be invoked"); | |
| 1837 } | |
| 1838 bool do_object_b(oop obj) { | |
| 1839 HeapWord* addr = (HeapWord*)obj; | |
| 1840 return addr != NULL && | |
| 1841 (!_g1->is_in_g1_reserved(addr) || !_g1->is_obj_ill(obj)); | |
| 1842 } | |
| 1843 }; | |
| 1844 | |
| 1845 class G1CMKeepAliveClosure: public OopClosure { | |
| 1846 G1CollectedHeap* _g1; | |
| 1847 ConcurrentMark* _cm; | |
| 1848 CMBitMap* _bitMap; | |
| 1849 public: | |
| 1850 G1CMKeepAliveClosure(G1CollectedHeap* g1, ConcurrentMark* cm, | |
| 1851 CMBitMap* bitMap) : | |
| 1852 _g1(g1), _cm(cm), | |
| 1853 _bitMap(bitMap) {} | |
| 1854 | |
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1855 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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1856 virtual void do_oop( oop* p) { do_oop_work(p); } |
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1857 |
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1858 template <class T> void do_oop_work(T* p) { |
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1859 oop thisOop = oopDesc::load_decode_heap_oop(p); |
| 342 | 1860 HeapWord* addr = (HeapWord*)thisOop; |
| 1861 if (_g1->is_in_g1_reserved(addr) && _g1->is_obj_ill(thisOop)) { | |
| 1862 _bitMap->mark(addr); | |
| 1863 _cm->mark_stack_push(thisOop); | |
| 1864 } | |
| 1865 } | |
| 1866 }; | |
| 1867 | |
| 1868 class G1CMDrainMarkingStackClosure: public VoidClosure { | |
| 1869 CMMarkStack* _markStack; | |
| 1870 CMBitMap* _bitMap; | |
| 1871 G1CMKeepAliveClosure* _oopClosure; | |
| 1872 public: | |
| 1873 G1CMDrainMarkingStackClosure(CMBitMap* bitMap, CMMarkStack* markStack, | |
| 1874 G1CMKeepAliveClosure* oopClosure) : | |
| 1875 _bitMap(bitMap), | |
| 1876 _markStack(markStack), | |
| 1877 _oopClosure(oopClosure) | |
| 1878 {} | |
| 1879 | |
| 1880 void do_void() { | |
| 1881 _markStack->drain((OopClosure*)_oopClosure, _bitMap, false); | |
| 1882 } | |
| 1883 }; | |
| 1884 | |
| 1885 void ConcurrentMark::weakRefsWork(bool clear_all_soft_refs) { | |
| 1886 ResourceMark rm; | |
| 1887 HandleMark hm; | |
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1888 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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1889 ReferenceProcessor* rp = g1h->ref_processor(); |
| 342 | 1890 |
| 1891 // Process weak references. | |
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1892 rp->setup_policy(clear_all_soft_refs); |
| 342 | 1893 assert(_markStack.isEmpty(), "mark stack should be empty"); |
| 1894 | |
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1895 G1CMIsAliveClosure g1IsAliveClosure (g1h); |
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1896 G1CMKeepAliveClosure g1KeepAliveClosure(g1h, this, nextMarkBitMap()); |
| 342 | 1897 G1CMDrainMarkingStackClosure |
| 1898 g1DrainMarkingStackClosure(nextMarkBitMap(), &_markStack, | |
| 1899 &g1KeepAliveClosure); | |
| 1900 | |
| 1901 // XXXYYY Also: copy the parallel ref processing code from CMS. | |
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1902 rp->process_discovered_references(&g1IsAliveClosure, |
| 342 | 1903 &g1KeepAliveClosure, |
| 1904 &g1DrainMarkingStackClosure, | |
| 1905 NULL); | |
| 1906 assert(_markStack.overflow() || _markStack.isEmpty(), | |
| 1907 "mark stack should be empty (unless it overflowed)"); | |
| 1908 if (_markStack.overflow()) { | |
| 1909 set_has_overflown(); | |
| 1910 } | |
| 1911 | |
| 1912 rp->enqueue_discovered_references(); | |
| 1913 rp->verify_no_references_recorded(); | |
| 1914 assert(!rp->discovery_enabled(), "should have been disabled"); | |
| 1915 | |
| 1916 // Now clean up stale oops in SymbolTable and StringTable | |
| 1917 SymbolTable::unlink(&g1IsAliveClosure); | |
| 1918 StringTable::unlink(&g1IsAliveClosure); | |
| 1919 } | |
| 1920 | |
| 1921 void ConcurrentMark::swapMarkBitMaps() { | |
| 1922 CMBitMapRO* temp = _prevMarkBitMap; | |
| 1923 _prevMarkBitMap = (CMBitMapRO*)_nextMarkBitMap; | |
| 1924 _nextMarkBitMap = (CMBitMap*) temp; | |
| 1925 } | |
| 1926 | |
| 1927 class CMRemarkTask: public AbstractGangTask { | |
| 1928 private: | |
| 1929 ConcurrentMark *_cm; | |
| 1930 | |
| 1931 public: | |
| 1932 void work(int worker_i) { | |
| 1933 // Since all available tasks are actually started, we should | |
| 1934 // only proceed if we're supposed to be actived. | |
| 1935 if ((size_t)worker_i < _cm->active_tasks()) { | |
| 1936 CMTask* task = _cm->task(worker_i); | |
| 1937 task->record_start_time(); | |
| 1938 do { | |
| 1939 task->do_marking_step(1000000000.0 /* something very large */); | |
| 1940 } while (task->has_aborted() && !_cm->has_overflown()); | |
| 1941 // If we overflow, then we do not want to restart. We instead | |
| 1942 // want to abort remark and do concurrent marking again. | |
| 1943 task->record_end_time(); | |
| 1944 } | |
| 1945 } | |
| 1946 | |
| 1947 CMRemarkTask(ConcurrentMark* cm) : | |
| 1948 AbstractGangTask("Par Remark"), _cm(cm) { } | |
| 1949 }; | |
| 1950 | |
| 1951 void ConcurrentMark::checkpointRootsFinalWork() { | |
| 1952 ResourceMark rm; | |
| 1953 HandleMark hm; | |
| 1954 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1955 | |
| 1956 g1h->ensure_parsability(false); | |
| 1957 | |
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1958 if (G1CollectedHeap::use_parallel_gc_threads()) { |
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1959 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1960 // this is remark, so we'll use up all available threads |
| 1961 int active_workers = ParallelGCThreads; | |
| 1962 set_phase(active_workers, false); | |
| 1963 | |
| 1964 CMRemarkTask remarkTask(this); | |
| 1965 // We will start all available threads, even if we decide that the | |
| 1966 // active_workers will be fewer. The extra ones will just bail out | |
| 1967 // immediately. | |
| 1968 int n_workers = g1h->workers()->total_workers(); | |
| 1969 g1h->set_par_threads(n_workers); | |
| 1970 g1h->workers()->run_task(&remarkTask); | |
| 1971 g1h->set_par_threads(0); | |
| 1972 } else { | |
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1973 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1974 // this is remark, so we'll use up all available threads |
| 1975 int active_workers = 1; | |
| 1976 set_phase(active_workers, false); | |
| 1977 | |
| 1978 CMRemarkTask remarkTask(this); | |
| 1979 // We will start all available threads, even if we decide that the | |
| 1980 // active_workers will be fewer. The extra ones will just bail out | |
| 1981 // immediately. | |
| 1982 remarkTask.work(0); | |
| 1983 } | |
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1984 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); |
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1985 guarantee(satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 1986 |
| 1987 print_stats(); | |
| 1988 | |
| 1989 if (!restart_for_overflow()) | |
| 1990 set_non_marking_state(); | |
| 1991 | |
| 1992 #if VERIFY_OBJS_PROCESSED | |
| 1993 if (_scan_obj_cl.objs_processed != ThreadLocalObjQueue::objs_enqueued) { | |
| 1994 gclog_or_tty->print_cr("Processed = %d, enqueued = %d.", | |
| 1995 _scan_obj_cl.objs_processed, | |
| 1996 ThreadLocalObjQueue::objs_enqueued); | |
| 1997 guarantee(_scan_obj_cl.objs_processed == | |
| 1998 ThreadLocalObjQueue::objs_enqueued, | |
| 1999 "Different number of objs processed and enqueued."); | |
| 2000 } | |
| 2001 #endif | |
| 2002 } | |
| 2003 | |
| 1044 | 2004 #ifndef PRODUCT |
| 2005 | |
| 1388 | 2006 class PrintReachableOopClosure: public OopClosure { |
| 342 | 2007 private: |
| 2008 G1CollectedHeap* _g1h; | |
| 2009 CMBitMapRO* _bitmap; | |
| 2010 outputStream* _out; | |
| 1044 | 2011 bool _use_prev_marking; |
| 1388 | 2012 bool _all; |
| 342 | 2013 |
| 2014 public: | |
| 1388 | 2015 PrintReachableOopClosure(CMBitMapRO* bitmap, |
| 2016 outputStream* out, | |
| 2017 bool use_prev_marking, | |
| 2018 bool all) : | |
| 1044 | 2019 _g1h(G1CollectedHeap::heap()), |
| 1388 | 2020 _bitmap(bitmap), _out(out), _use_prev_marking(use_prev_marking), _all(all) { } |
| 342 | 2021 |
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2022 void do_oop(narrowOop* p) { do_oop_work(p); } |
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2023 void do_oop( oop* p) { do_oop_work(p); } |
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2024 |
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2025 template <class T> void do_oop_work(T* p) { |
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2026 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2027 const char* str = NULL; |
| 2028 const char* str2 = ""; | |
| 2029 | |
| 1388 | 2030 if (obj == NULL) { |
| 2031 str = ""; | |
| 2032 } else if (!_g1h->is_in_g1_reserved(obj)) { | |
| 2033 str = " O"; | |
| 2034 } else { | |
| 342 | 2035 HeapRegion* hr = _g1h->heap_region_containing(obj); |
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2036 guarantee(hr != NULL, "invariant"); |
| 1044 | 2037 bool over_tams = false; |
| 2038 if (_use_prev_marking) { | |
| 2039 over_tams = hr->obj_allocated_since_prev_marking(obj); | |
| 2040 } else { | |
| 2041 over_tams = hr->obj_allocated_since_next_marking(obj); | |
| 2042 } | |
| 1388 | 2043 bool marked = _bitmap->isMarked((HeapWord*) obj); |
| 1044 | 2044 |
| 2045 if (over_tams) { | |
| 1388 | 2046 str = " >"; |
| 2047 if (marked) { | |
| 342 | 2048 str2 = " AND MARKED"; |
| 1044 | 2049 } |
| 1388 | 2050 } else if (marked) { |
| 2051 str = " M"; | |
| 1044 | 2052 } else { |
| 1388 | 2053 str = " NOT"; |
| 1044 | 2054 } |
| 342 | 2055 } |
| 2056 | |
| 1388 | 2057 _out->print_cr(" "PTR_FORMAT": "PTR_FORMAT"%s%s", |
| 342 | 2058 p, (void*) obj, str, str2); |
| 2059 } | |
| 2060 }; | |
| 2061 | |
| 1388 | 2062 class PrintReachableObjectClosure : public ObjectClosure { |
| 342 | 2063 private: |
| 1044 | 2064 CMBitMapRO* _bitmap; |
| 342 | 2065 outputStream* _out; |
| 1044 | 2066 bool _use_prev_marking; |
| 1388 | 2067 bool _all; |
| 2068 HeapRegion* _hr; | |
| 342 | 2069 |
| 2070 public: | |
| 1388 | 2071 PrintReachableObjectClosure(CMBitMapRO* bitmap, |
| 2072 outputStream* out, | |
| 2073 bool use_prev_marking, | |
| 2074 bool all, | |
| 2075 HeapRegion* hr) : | |
| 2076 _bitmap(bitmap), _out(out), | |
| 2077 _use_prev_marking(use_prev_marking), _all(all), _hr(hr) { } | |
| 2078 | |
| 2079 void do_object(oop o) { | |
| 2080 bool over_tams; | |
| 2081 if (_use_prev_marking) { | |
| 2082 over_tams = _hr->obj_allocated_since_prev_marking(o); | |
| 2083 } else { | |
| 2084 over_tams = _hr->obj_allocated_since_next_marking(o); | |
| 2085 } | |
| 2086 bool marked = _bitmap->isMarked((HeapWord*) o); | |
| 2087 bool print_it = _all || over_tams || marked; | |
| 2088 | |
| 2089 if (print_it) { | |
| 2090 _out->print_cr(" "PTR_FORMAT"%s", | |
| 2091 o, (over_tams) ? " >" : (marked) ? " M" : ""); | |
| 2092 PrintReachableOopClosure oopCl(_bitmap, _out, _use_prev_marking, _all); | |
| 2093 o->oop_iterate(&oopCl); | |
| 2094 } | |
| 342 | 2095 } |
| 2096 }; | |
| 2097 | |
| 1388 | 2098 class PrintReachableRegionClosure : public HeapRegionClosure { |
| 342 | 2099 private: |
| 1044 | 2100 CMBitMapRO* _bitmap; |
| 342 | 2101 outputStream* _out; |
| 1044 | 2102 bool _use_prev_marking; |
| 1388 | 2103 bool _all; |
| 342 | 2104 |
| 2105 public: | |
| 2106 bool doHeapRegion(HeapRegion* hr) { | |
| 2107 HeapWord* b = hr->bottom(); | |
| 2108 HeapWord* e = hr->end(); | |
| 2109 HeapWord* t = hr->top(); | |
| 1044 | 2110 HeapWord* p = NULL; |
| 2111 if (_use_prev_marking) { | |
| 2112 p = hr->prev_top_at_mark_start(); | |
| 2113 } else { | |
| 2114 p = hr->next_top_at_mark_start(); | |
| 2115 } | |
| 342 | 2116 _out->print_cr("** ["PTR_FORMAT", "PTR_FORMAT"] top: "PTR_FORMAT" " |
| 1044 | 2117 "TAMS: "PTR_FORMAT, b, e, t, p); |
| 1388 | 2118 _out->cr(); |
| 2119 | |
| 2120 HeapWord* from = b; | |
| 2121 HeapWord* to = t; | |
| 2122 | |
| 2123 if (to > from) { | |
| 2124 _out->print_cr("Objects in ["PTR_FORMAT", "PTR_FORMAT"]", from, to); | |
| 2125 _out->cr(); | |
| 2126 PrintReachableObjectClosure ocl(_bitmap, _out, | |
| 2127 _use_prev_marking, _all, hr); | |
| 2128 hr->object_iterate_mem_careful(MemRegion(from, to), &ocl); | |
| 2129 _out->cr(); | |
| 2130 } | |
| 342 | 2131 |
| 2132 return false; | |
| 2133 } | |
| 2134 | |
| 1388 | 2135 PrintReachableRegionClosure(CMBitMapRO* bitmap, |
| 2136 outputStream* out, | |
| 2137 bool use_prev_marking, | |
| 2138 bool all) : | |
| 2139 _bitmap(bitmap), _out(out), _use_prev_marking(use_prev_marking), _all(all) { } | |
| 342 | 2140 }; |
| 2141 | |
| 1388 | 2142 void ConcurrentMark::print_reachable(const char* str, |
| 2143 bool use_prev_marking, | |
| 2144 bool all) { | |
| 2145 gclog_or_tty->cr(); | |
| 2146 gclog_or_tty->print_cr("== Doing heap dump... "); | |
| 1044 | 2147 |
| 2148 if (G1PrintReachableBaseFile == NULL) { | |
| 2149 gclog_or_tty->print_cr(" #### error: no base file defined"); | |
| 2150 return; | |
| 2151 } | |
| 2152 | |
| 2153 if (strlen(G1PrintReachableBaseFile) + 1 + strlen(str) > | |
| 2154 (JVM_MAXPATHLEN - 1)) { | |
| 2155 gclog_or_tty->print_cr(" #### error: file name too long"); | |
| 2156 return; | |
| 2157 } | |
| 2158 | |
| 2159 char file_name[JVM_MAXPATHLEN]; | |
| 2160 sprintf(file_name, "%s.%s", G1PrintReachableBaseFile, str); | |
| 2161 gclog_or_tty->print_cr(" dumping to file %s", file_name); | |
| 2162 | |
| 2163 fileStream fout(file_name); | |
| 2164 if (!fout.is_open()) { | |
| 2165 gclog_or_tty->print_cr(" #### error: could not open file"); | |
| 2166 return; | |
| 2167 } | |
| 2168 | |
| 2169 outputStream* out = &fout; | |
| 2170 | |
| 2171 CMBitMapRO* bitmap = NULL; | |
| 2172 if (use_prev_marking) { | |
| 2173 bitmap = _prevMarkBitMap; | |
| 2174 } else { | |
| 2175 bitmap = _nextMarkBitMap; | |
| 2176 } | |
| 2177 | |
| 2178 out->print_cr("-- USING %s", (use_prev_marking) ? "PTAMS" : "NTAMS"); | |
| 2179 out->cr(); | |
| 2180 | |
| 1388 | 2181 out->print_cr("--- ITERATING OVER REGIONS"); |
| 1044 | 2182 out->cr(); |
| 1388 | 2183 PrintReachableRegionClosure rcl(bitmap, out, use_prev_marking, all); |
| 2184 _g1h->heap_region_iterate(&rcl); | |
| 1044 | 2185 out->cr(); |
| 2186 | |
| 2187 gclog_or_tty->print_cr(" done"); | |
| 1388 | 2188 gclog_or_tty->flush(); |
| 342 | 2189 } |
| 2190 | |
| 1044 | 2191 #endif // PRODUCT |
| 2192 | |
| 342 | 2193 // This note is for drainAllSATBBuffers and the code in between. |
| 2194 // In the future we could reuse a task to do this work during an | |
| 2195 // evacuation pause (since now tasks are not active and can be claimed | |
| 2196 // during an evacuation pause). This was a late change to the code and | |
| 2197 // is currently not being taken advantage of. | |
| 2198 | |
| 2199 class CMGlobalObjectClosure : public ObjectClosure { | |
| 2200 private: | |
| 2201 ConcurrentMark* _cm; | |
| 2202 | |
| 2203 public: | |
| 2204 void do_object(oop obj) { | |
| 2205 _cm->deal_with_reference(obj); | |
| 2206 } | |
| 2207 | |
| 2208 CMGlobalObjectClosure(ConcurrentMark* cm) : _cm(cm) { } | |
| 2209 }; | |
| 2210 | |
| 2211 void ConcurrentMark::deal_with_reference(oop obj) { | |
| 2212 if (verbose_high()) | |
| 2213 gclog_or_tty->print_cr("[global] we're dealing with reference "PTR_FORMAT, | |
| 2214 (void*) obj); | |
| 2215 | |
| 2216 | |
| 2217 HeapWord* objAddr = (HeapWord*) obj; | |
|
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2218 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 2219 if (_g1h->is_in_g1_reserved(objAddr)) { |
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2220 assert(obj != NULL, "is_in_g1_reserved should ensure this"); |
| 342 | 2221 HeapRegion* hr = _g1h->heap_region_containing(obj); |
| 2222 if (_g1h->is_obj_ill(obj, hr)) { | |
| 2223 if (verbose_high()) | |
| 2224 gclog_or_tty->print_cr("[global] "PTR_FORMAT" is not considered " | |
| 2225 "marked", (void*) obj); | |
| 2226 | |
| 2227 // we need to mark it first | |
| 2228 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 2229 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 2230 // CAS done in parMark(objAddr) above | |
| 2231 HeapWord* finger = _finger; | |
| 2232 if (objAddr < finger) { | |
| 2233 if (verbose_high()) | |
| 2234 gclog_or_tty->print_cr("[global] below the global finger " | |
| 2235 "("PTR_FORMAT"), pushing it", finger); | |
| 2236 if (!mark_stack_push(obj)) { | |
| 2237 if (verbose_low()) | |
| 2238 gclog_or_tty->print_cr("[global] global stack overflow during " | |
| 2239 "deal_with_reference"); | |
| 2240 } | |
| 2241 } | |
| 2242 } | |
| 2243 } | |
| 2244 } | |
| 2245 } | |
| 2246 | |
| 2247 void ConcurrentMark::drainAllSATBBuffers() { | |
| 2248 CMGlobalObjectClosure oc(this); | |
| 2249 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2250 satb_mq_set.set_closure(&oc); | |
| 2251 | |
| 2252 while (satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 2253 if (verbose_medium()) | |
| 2254 gclog_or_tty->print_cr("[global] processed an SATB buffer"); | |
| 2255 } | |
| 2256 | |
| 2257 // no need to check whether we should do this, as this is only | |
| 2258 // called during an evacuation pause | |
| 2259 satb_mq_set.iterate_closure_all_threads(); | |
| 2260 | |
| 2261 satb_mq_set.set_closure(NULL); | |
|
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2262 assert(satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 2263 } |
| 2264 | |
| 2265 void ConcurrentMark::markPrev(oop p) { | |
| 2266 // Note we are overriding the read-only view of the prev map here, via | |
| 2267 // the cast. | |
| 2268 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*)p); | |
| 2269 } | |
| 2270 | |
| 2271 void ConcurrentMark::clear(oop p) { | |
| 2272 assert(p != NULL && p->is_oop(), "expected an oop"); | |
| 2273 HeapWord* addr = (HeapWord*)p; | |
| 2274 assert(addr >= _nextMarkBitMap->startWord() || | |
| 2275 addr < _nextMarkBitMap->endWord(), "in a region"); | |
| 2276 | |
| 2277 _nextMarkBitMap->clear(addr); | |
| 2278 } | |
| 2279 | |
| 2280 void ConcurrentMark::clearRangeBothMaps(MemRegion mr) { | |
| 2281 // Note we are overriding the read-only view of the prev map here, via | |
| 2282 // the cast. | |
| 2283 ((CMBitMap*)_prevMarkBitMap)->clearRange(mr); | |
| 2284 _nextMarkBitMap->clearRange(mr); | |
| 2285 } | |
| 2286 | |
| 2287 HeapRegion* | |
| 2288 ConcurrentMark::claim_region(int task_num) { | |
| 2289 // "checkpoint" the finger | |
| 2290 HeapWord* finger = _finger; | |
| 2291 | |
| 2292 // _heap_end will not change underneath our feet; it only changes at | |
| 2293 // yield points. | |
| 2294 while (finger < _heap_end) { | |
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2295 assert(_g1h->is_in_g1_reserved(finger), "invariant"); |
| 342 | 2296 |
| 2297 // is the gap between reading the finger and doing the CAS too long? | |
| 2298 | |
| 2299 HeapRegion* curr_region = _g1h->heap_region_containing(finger); | |
| 2300 HeapWord* bottom = curr_region->bottom(); | |
| 2301 HeapWord* end = curr_region->end(); | |
| 2302 HeapWord* limit = curr_region->next_top_at_mark_start(); | |
| 2303 | |
| 2304 if (verbose_low()) | |
| 2305 gclog_or_tty->print_cr("[%d] curr_region = "PTR_FORMAT" " | |
| 2306 "["PTR_FORMAT", "PTR_FORMAT"), " | |
| 2307 "limit = "PTR_FORMAT, | |
| 2308 task_num, curr_region, bottom, end, limit); | |
| 2309 | |
| 2310 HeapWord* res = | |
| 2311 (HeapWord*) Atomic::cmpxchg_ptr(end, &_finger, finger); | |
| 2312 if (res == finger) { | |
| 2313 // we succeeded | |
| 2314 | |
| 2315 // notice that _finger == end cannot be guaranteed here since, | |
| 2316 // someone else might have moved the finger even further | |
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2317 assert(_finger >= end, "the finger should have moved forward"); |
| 342 | 2318 |
| 2319 if (verbose_low()) | |
| 2320 gclog_or_tty->print_cr("[%d] we were successful with region = " | |
| 2321 PTR_FORMAT, task_num, curr_region); | |
| 2322 | |
| 2323 if (limit > bottom) { | |
| 2324 if (verbose_low()) | |
| 2325 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is not empty, " | |
| 2326 "returning it ", task_num, curr_region); | |
| 2327 return curr_region; | |
| 2328 } else { | |
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2329 assert(limit == bottom, |
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2330 "the region limit should be at bottom"); |
| 342 | 2331 if (verbose_low()) |
| 2332 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is empty, " | |
| 2333 "returning NULL", task_num, curr_region); | |
| 2334 // we return NULL and the caller should try calling | |
| 2335 // claim_region() again. | |
| 2336 return NULL; | |
| 2337 } | |
| 2338 } else { | |
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2339 assert(_finger > finger, "the finger should have moved forward"); |
| 342 | 2340 if (verbose_low()) |
| 2341 gclog_or_tty->print_cr("[%d] somebody else moved the finger, " | |
| 2342 "global finger = "PTR_FORMAT", " | |
| 2343 "our finger = "PTR_FORMAT, | |
| 2344 task_num, _finger, finger); | |
| 2345 | |
| 2346 // read it again | |
| 2347 finger = _finger; | |
| 2348 } | |
| 2349 } | |
| 2350 | |
| 2351 return NULL; | |
| 2352 } | |
| 2353 | |
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2354 bool ConcurrentMark::invalidate_aborted_regions_in_cset() { |
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2355 bool result = false; |
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2356 for (int i = 0; i < (int)_max_task_num; ++i) { |
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2357 CMTask* the_task = _tasks[i]; |
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2358 MemRegion mr = the_task->aborted_region(); |
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2359 if (mr.start() != NULL) { |
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2360 assert(mr.end() != NULL, "invariant"); |
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2361 assert(mr.word_size() > 0, "invariant"); |
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2362 HeapRegion* hr = _g1h->heap_region_containing(mr.start()); |
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2363 assert(hr != NULL, "invariant"); |
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2364 if (hr->in_collection_set()) { |
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2365 // The region points into the collection set |
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2366 the_task->set_aborted_region(MemRegion()); |
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2367 result = true; |
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2368 } |
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2369 } |
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2370 } |
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2371 return result; |
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2372 } |
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2373 |
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2374 bool ConcurrentMark::has_aborted_regions() { |
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2375 for (int i = 0; i < (int)_max_task_num; ++i) { |
|
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2376 CMTask* the_task = _tasks[i]; |
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2377 MemRegion mr = the_task->aborted_region(); |
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2378 if (mr.start() != NULL) { |
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2379 assert(mr.end() != NULL, "invariant"); |
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2380 assert(mr.word_size() > 0, "invariant"); |
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2381 return true; |
|
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|
2382 } |
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|
2383 } |
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|
2384 return false; |
|
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|
2385 } |
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|
2386 |
| 342 | 2387 void ConcurrentMark::oops_do(OopClosure* cl) { |
| 2388 if (_markStack.size() > 0 && verbose_low()) | |
| 2389 gclog_or_tty->print_cr("[global] scanning the global marking stack, " | |
| 2390 "size = %d", _markStack.size()); | |
| 2391 // we first iterate over the contents of the mark stack... | |
| 2392 _markStack.oops_do(cl); | |
| 2393 | |
| 2394 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2395 OopTaskQueue* queue = _task_queues->queue((int)i); | |
| 2396 | |
| 2397 if (queue->size() > 0 && verbose_low()) | |
| 2398 gclog_or_tty->print_cr("[global] scanning task queue of task %d, " | |
| 2399 "size = %d", i, queue->size()); | |
| 2400 | |
| 2401 // ...then over the contents of the all the task queues. | |
| 2402 queue->oops_do(cl); | |
| 2403 } | |
| 2404 | |
|
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|
2405 // Invalidate any entries, that are in the region stack, that |
| 342 | 2406 // point into the collection set |
| 2407 if (_regionStack.invalidate_entries_into_cset()) { | |
| 2408 // otherwise, any gray objects copied during the evacuation pause | |
| 2409 // might not be visited. | |
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2410 assert(_should_gray_objects, "invariant"); |
| 342 | 2411 } |
|
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2412 |
|
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|
2413 // Invalidate any aborted regions, recorded in the individual CM |
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2414 // tasks, that point into the collection set. |
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2415 if (invalidate_aborted_regions_in_cset()) { |
|
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2416 // otherwise, any gray objects copied during the evacuation pause |
|
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2417 // might not be visited. |
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|
2418 assert(_should_gray_objects, "invariant"); |
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2419 } |
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|
2420 |
| 342 | 2421 } |
| 2422 | |
| 2423 void ConcurrentMark::clear_marking_state() { | |
| 2424 _markStack.setEmpty(); | |
| 2425 _markStack.clear_overflow(); | |
| 2426 _regionStack.setEmpty(); | |
| 2427 _regionStack.clear_overflow(); | |
| 2428 clear_has_overflown(); | |
| 2429 _finger = _heap_start; | |
| 2430 | |
| 2431 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2432 OopTaskQueue* queue = _task_queues->queue(i); | |
| 2433 queue->set_empty(); | |
|
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2434 // Clear any partial regions from the CMTasks |
|
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|
2435 _tasks[i]->clear_aborted_region(); |
| 342 | 2436 } |
| 2437 } | |
| 2438 | |
| 2439 void ConcurrentMark::print_stats() { | |
| 2440 if (verbose_stats()) { | |
| 2441 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2442 for (size_t i = 0; i < _active_tasks; ++i) { | |
| 2443 _tasks[i]->print_stats(); | |
| 2444 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2445 } | |
| 2446 } | |
| 2447 } | |
| 2448 | |
| 2449 class CSMarkOopClosure: public OopClosure { | |
| 2450 friend class CSMarkBitMapClosure; | |
| 2451 | |
| 2452 G1CollectedHeap* _g1h; | |
| 2453 CMBitMap* _bm; | |
| 2454 ConcurrentMark* _cm; | |
| 2455 oop* _ms; | |
| 2456 jint* _array_ind_stack; | |
| 2457 int _ms_size; | |
| 2458 int _ms_ind; | |
| 2459 int _array_increment; | |
| 2460 | |
| 2461 bool push(oop obj, int arr_ind = 0) { | |
| 2462 if (_ms_ind == _ms_size) { | |
| 2463 gclog_or_tty->print_cr("Mark stack is full."); | |
| 2464 return false; | |
| 2465 } | |
| 2466 _ms[_ms_ind] = obj; | |
| 2467 if (obj->is_objArray()) _array_ind_stack[_ms_ind] = arr_ind; | |
| 2468 _ms_ind++; | |
| 2469 return true; | |
| 2470 } | |
| 2471 | |
| 2472 oop pop() { | |
| 2473 if (_ms_ind == 0) return NULL; | |
| 2474 else { | |
| 2475 _ms_ind--; | |
| 2476 return _ms[_ms_ind]; | |
| 2477 } | |
| 2478 } | |
| 2479 | |
|
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2480 template <class T> bool drain() { |
| 342 | 2481 while (_ms_ind > 0) { |
| 2482 oop obj = pop(); | |
| 2483 assert(obj != NULL, "Since index was non-zero."); | |
| 2484 if (obj->is_objArray()) { | |
| 2485 jint arr_ind = _array_ind_stack[_ms_ind]; | |
| 2486 objArrayOop aobj = objArrayOop(obj); | |
| 2487 jint len = aobj->length(); | |
| 2488 jint next_arr_ind = arr_ind + _array_increment; | |
| 2489 if (next_arr_ind < len) { | |
| 2490 push(obj, next_arr_ind); | |
| 2491 } | |
| 2492 // Now process this portion of this one. | |
| 2493 int lim = MIN2(next_arr_ind, len); | |
| 2494 for (int j = arr_ind; j < lim; j++) { | |
|
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|
2495 do_oop(aobj->objArrayOopDesc::obj_at_addr<T>(j)); |
| 342 | 2496 } |
| 2497 | |
| 2498 } else { | |
| 2499 obj->oop_iterate(this); | |
| 2500 } | |
| 2501 if (abort()) return false; | |
| 2502 } | |
| 2503 return true; | |
| 2504 } | |
| 2505 | |
| 2506 public: | |
| 2507 CSMarkOopClosure(ConcurrentMark* cm, int ms_size) : | |
| 2508 _g1h(G1CollectedHeap::heap()), | |
| 2509 _cm(cm), | |
| 2510 _bm(cm->nextMarkBitMap()), | |
| 2511 _ms_size(ms_size), _ms_ind(0), | |
| 2512 _ms(NEW_C_HEAP_ARRAY(oop, ms_size)), | |
| 2513 _array_ind_stack(NEW_C_HEAP_ARRAY(jint, ms_size)), | |
| 2514 _array_increment(MAX2(ms_size/8, 16)) | |
| 2515 {} | |
| 2516 | |
| 2517 ~CSMarkOopClosure() { | |
| 2518 FREE_C_HEAP_ARRAY(oop, _ms); | |
| 2519 FREE_C_HEAP_ARRAY(jint, _array_ind_stack); | |
| 2520 } | |
| 2521 | |
|
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2522 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
|
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2523 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2524 |
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2525 template <class T> void do_oop_work(T* p) { |
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2526 T heap_oop = oopDesc::load_heap_oop(p); |
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2527 if (oopDesc::is_null(heap_oop)) return; |
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2528 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
| 342 | 2529 if (obj->is_forwarded()) { |
| 2530 // If the object has already been forwarded, we have to make sure | |
| 2531 // that it's marked. So follow the forwarding pointer. Note that | |
| 2532 // this does the right thing for self-forwarding pointers in the | |
| 2533 // evacuation failure case. | |
| 2534 obj = obj->forwardee(); | |
| 2535 } | |
| 2536 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2537 if (hr != NULL) { | |
| 2538 if (hr->in_collection_set()) { | |
| 2539 if (_g1h->is_obj_ill(obj)) { | |
| 2540 _bm->mark((HeapWord*)obj); | |
| 2541 if (!push(obj)) { | |
| 2542 gclog_or_tty->print_cr("Setting abort in CSMarkOopClosure because push failed."); | |
| 2543 set_abort(); | |
| 2544 } | |
| 2545 } | |
| 2546 } else { | |
| 2547 // Outside the collection set; we need to gray it | |
| 2548 _cm->deal_with_reference(obj); | |
| 2549 } | |
| 2550 } | |
| 2551 } | |
| 2552 }; | |
| 2553 | |
| 2554 class CSMarkBitMapClosure: public BitMapClosure { | |
| 2555 G1CollectedHeap* _g1h; | |
| 2556 CMBitMap* _bitMap; | |
| 2557 ConcurrentMark* _cm; | |
| 2558 CSMarkOopClosure _oop_cl; | |
| 2559 public: | |
| 2560 CSMarkBitMapClosure(ConcurrentMark* cm, int ms_size) : | |
| 2561 _g1h(G1CollectedHeap::heap()), | |
| 2562 _bitMap(cm->nextMarkBitMap()), | |
| 2563 _oop_cl(cm, ms_size) | |
| 2564 {} | |
| 2565 | |
| 2566 ~CSMarkBitMapClosure() {} | |
| 2567 | |
| 2568 bool do_bit(size_t offset) { | |
| 2569 // convert offset into a HeapWord* | |
| 2570 HeapWord* addr = _bitMap->offsetToHeapWord(offset); | |
| 2571 assert(_bitMap->endWord() && addr < _bitMap->endWord(), | |
| 2572 "address out of range"); | |
| 2573 assert(_bitMap->isMarked(addr), "tautology"); | |
| 2574 oop obj = oop(addr); | |
| 2575 if (!obj->is_forwarded()) { | |
| 2576 if (!_oop_cl.push(obj)) return false; | |
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2577 if (UseCompressedOops) { |
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2578 if (!_oop_cl.drain<narrowOop>()) return false; |
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2579 } else { |
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2580 if (!_oop_cl.drain<oop>()) return false; |
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2581 } |
| 342 | 2582 } |
| 2583 // Otherwise... | |
| 2584 return true; | |
| 2585 } | |
| 2586 }; | |
| 2587 | |
| 2588 | |
| 2589 class CompleteMarkingInCSHRClosure: public HeapRegionClosure { | |
| 2590 CMBitMap* _bm; | |
| 2591 CSMarkBitMapClosure _bit_cl; | |
| 2592 enum SomePrivateConstants { | |
| 2593 MSSize = 1000 | |
| 2594 }; | |
| 2595 bool _completed; | |
| 2596 public: | |
| 2597 CompleteMarkingInCSHRClosure(ConcurrentMark* cm) : | |
| 2598 _bm(cm->nextMarkBitMap()), | |
| 2599 _bit_cl(cm, MSSize), | |
| 2600 _completed(true) | |
| 2601 {} | |
| 2602 | |
| 2603 ~CompleteMarkingInCSHRClosure() {} | |
| 2604 | |
| 2605 bool doHeapRegion(HeapRegion* r) { | |
| 2606 if (!r->evacuation_failed()) { | |
| 2607 MemRegion mr = MemRegion(r->bottom(), r->next_top_at_mark_start()); | |
| 2608 if (!mr.is_empty()) { | |
| 2609 if (!_bm->iterate(&_bit_cl, mr)) { | |
| 2610 _completed = false; | |
| 2611 return true; | |
| 2612 } | |
| 2613 } | |
| 2614 } | |
| 2615 return false; | |
| 2616 } | |
| 2617 | |
| 2618 bool completed() { return _completed; } | |
| 2619 }; | |
| 2620 | |
| 2621 class ClearMarksInHRClosure: public HeapRegionClosure { | |
| 2622 CMBitMap* _bm; | |
| 2623 public: | |
| 2624 ClearMarksInHRClosure(CMBitMap* bm): _bm(bm) { } | |
| 2625 | |
| 2626 bool doHeapRegion(HeapRegion* r) { | |
| 2627 if (!r->used_region().is_empty() && !r->evacuation_failed()) { | |
| 2628 MemRegion usedMR = r->used_region(); | |
| 2629 _bm->clearRange(r->used_region()); | |
| 2630 } | |
| 2631 return false; | |
| 2632 } | |
| 2633 }; | |
| 2634 | |
| 2635 void ConcurrentMark::complete_marking_in_collection_set() { | |
| 2636 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 2637 | |
| 2638 if (!g1h->mark_in_progress()) { | |
| 2639 g1h->g1_policy()->record_mark_closure_time(0.0); | |
| 2640 return; | |
| 2641 } | |
| 2642 | |
| 2643 int i = 1; | |
| 2644 double start = os::elapsedTime(); | |
| 2645 while (true) { | |
| 2646 i++; | |
| 2647 CompleteMarkingInCSHRClosure cmplt(this); | |
| 2648 g1h->collection_set_iterate(&cmplt); | |
| 2649 if (cmplt.completed()) break; | |
| 2650 } | |
| 2651 double end_time = os::elapsedTime(); | |
| 2652 double elapsed_time_ms = (end_time - start) * 1000.0; | |
| 2653 g1h->g1_policy()->record_mark_closure_time(elapsed_time_ms); | |
| 2654 | |
| 2655 ClearMarksInHRClosure clr(nextMarkBitMap()); | |
| 2656 g1h->collection_set_iterate(&clr); | |
| 2657 } | |
| 2658 | |
| 2659 // The next two methods deal with the following optimisation. Some | |
| 2660 // objects are gray by being marked and located above the finger. If | |
| 2661 // they are copied, during an evacuation pause, below the finger then | |
| 2662 // the need to be pushed on the stack. The observation is that, if | |
| 2663 // there are no regions in the collection set located above the | |
| 2664 // finger, then the above cannot happen, hence we do not need to | |
| 2665 // explicitly gray any objects when copying them to below the | |
| 2666 // finger. The global stack will be scanned to ensure that, if it | |
| 2667 // points to objects being copied, it will update their | |
| 2668 // location. There is a tricky situation with the gray objects in | |
| 2669 // region stack that are being coped, however. See the comment in | |
| 2670 // newCSet(). | |
| 2671 | |
| 2672 void ConcurrentMark::newCSet() { | |
| 2673 if (!concurrent_marking_in_progress()) | |
| 2674 // nothing to do if marking is not in progress | |
| 2675 return; | |
| 2676 | |
| 2677 // find what the lowest finger is among the global and local fingers | |
| 2678 _min_finger = _finger; | |
| 2679 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2680 CMTask* task = _tasks[i]; | |
| 2681 HeapWord* task_finger = task->finger(); | |
| 2682 if (task_finger != NULL && task_finger < _min_finger) | |
| 2683 _min_finger = task_finger; | |
| 2684 } | |
| 2685 | |
| 2686 _should_gray_objects = false; | |
| 2687 | |
| 2688 // This fixes a very subtle and fustrating bug. It might be the case | |
| 2689 // that, during en evacuation pause, heap regions that contain | |
| 2690 // objects that are gray (by being in regions contained in the | |
| 2691 // region stack) are included in the collection set. Since such gray | |
| 2692 // objects will be moved, and because it's not easy to redirect | |
| 2693 // region stack entries to point to a new location (because objects | |
| 2694 // in one region might be scattered to multiple regions after they | |
| 2695 // are copied), one option is to ensure that all marked objects | |
| 2696 // copied during a pause are pushed on the stack. Notice, however, | |
| 2697 // that this problem can only happen when the region stack is not | |
| 2698 // empty during an evacuation pause. So, we make the fix a bit less | |
| 2699 // conservative and ensure that regions are pushed on the stack, | |
| 2700 // irrespective whether all collection set regions are below the | |
| 2701 // finger, if the region stack is not empty. This is expected to be | |
| 2702 // a rare case, so I don't think it's necessary to be smarted about it. | |
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2703 if (!region_stack_empty() || has_aborted_regions()) |
| 342 | 2704 _should_gray_objects = true; |
| 2705 } | |
| 2706 | |
| 2707 void ConcurrentMark::registerCSetRegion(HeapRegion* hr) { | |
| 2708 if (!concurrent_marking_in_progress()) | |
| 2709 return; | |
| 2710 | |
| 2711 HeapWord* region_end = hr->end(); | |
| 2712 if (region_end > _min_finger) | |
| 2713 _should_gray_objects = true; | |
| 2714 } | |
| 2715 | |
| 2716 // abandon current marking iteration due to a Full GC | |
| 2717 void ConcurrentMark::abort() { | |
| 2718 // Clear all marks to force marking thread to do nothing | |
| 2719 _nextMarkBitMap->clearAll(); | |
| 2720 // Empty mark stack | |
| 2721 clear_marking_state(); | |
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2722 for (int i = 0; i < (int)_max_task_num; ++i) { |
| 342 | 2723 _tasks[i]->clear_region_fields(); |
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2724 } |
| 342 | 2725 _has_aborted = true; |
| 2726 | |
| 2727 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2728 satb_mq_set.abandon_partial_marking(); | |
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2729 // This can be called either during or outside marking, we'll read |
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2730 // the expected_active value from the SATB queue set. |
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2731 satb_mq_set.set_active_all_threads( |
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2732 false, /* new active value */ |
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2733 satb_mq_set.is_active() /* expected_active */); |
| 342 | 2734 } |
| 2735 | |
| 2736 static void print_ms_time_info(const char* prefix, const char* name, | |
| 2737 NumberSeq& ns) { | |
| 2738 gclog_or_tty->print_cr("%s%5d %12s: total time = %8.2f s (avg = %8.2f ms).", | |
| 2739 prefix, ns.num(), name, ns.sum()/1000.0, ns.avg()); | |
| 2740 if (ns.num() > 0) { | |
| 2741 gclog_or_tty->print_cr("%s [std. dev = %8.2f ms, max = %8.2f ms]", | |
| 2742 prefix, ns.sd(), ns.maximum()); | |
| 2743 } | |
| 2744 } | |
| 2745 | |
| 2746 void ConcurrentMark::print_summary_info() { | |
| 2747 gclog_or_tty->print_cr(" Concurrent marking:"); | |
| 2748 print_ms_time_info(" ", "init marks", _init_times); | |
| 2749 print_ms_time_info(" ", "remarks", _remark_times); | |
| 2750 { | |
| 2751 print_ms_time_info(" ", "final marks", _remark_mark_times); | |
| 2752 print_ms_time_info(" ", "weak refs", _remark_weak_ref_times); | |
| 2753 | |
| 2754 } | |
| 2755 print_ms_time_info(" ", "cleanups", _cleanup_times); | |
| 2756 gclog_or_tty->print_cr(" Final counting total time = %8.2f s (avg = %8.2f ms).", | |
| 2757 _total_counting_time, | |
| 2758 (_cleanup_times.num() > 0 ? _total_counting_time * 1000.0 / | |
| 2759 (double)_cleanup_times.num() | |
| 2760 : 0.0)); | |
| 2761 if (G1ScrubRemSets) { | |
| 2762 gclog_or_tty->print_cr(" RS scrub total time = %8.2f s (avg = %8.2f ms).", | |
| 2763 _total_rs_scrub_time, | |
| 2764 (_cleanup_times.num() > 0 ? _total_rs_scrub_time * 1000.0 / | |
| 2765 (double)_cleanup_times.num() | |
| 2766 : 0.0)); | |
| 2767 } | |
| 2768 gclog_or_tty->print_cr(" Total stop_world time = %8.2f s.", | |
| 2769 (_init_times.sum() + _remark_times.sum() + | |
| 2770 _cleanup_times.sum())/1000.0); | |
| 2771 gclog_or_tty->print_cr(" Total concurrent time = %8.2f s " | |
| 2772 "(%8.2f s marking, %8.2f s counting).", | |
| 2773 cmThread()->vtime_accum(), | |
| 2774 cmThread()->vtime_mark_accum(), | |
| 2775 cmThread()->vtime_count_accum()); | |
| 2776 } | |
| 2777 | |
| 1019 | 2778 void ConcurrentMark::print_worker_threads_on(outputStream* st) const { |
| 2779 _parallel_workers->print_worker_threads_on(st); | |
| 2780 } | |
| 2781 | |
| 342 | 2782 // Closures |
| 2783 // XXX: there seems to be a lot of code duplication here; | |
| 2784 // should refactor and consolidate the shared code. | |
| 2785 | |
| 2786 // This closure is used to mark refs into the CMS generation in | |
| 2787 // the CMS bit map. Called at the first checkpoint. | |
| 2788 | |
| 2789 // We take a break if someone is trying to stop the world. | |
| 2790 bool ConcurrentMark::do_yield_check(int worker_i) { | |
| 2791 if (should_yield()) { | |
| 2792 if (worker_i == 0) | |
| 2793 _g1h->g1_policy()->record_concurrent_pause(); | |
| 2794 cmThread()->yield(); | |
| 2795 if (worker_i == 0) | |
| 2796 _g1h->g1_policy()->record_concurrent_pause_end(); | |
| 2797 return true; | |
| 2798 } else { | |
| 2799 return false; | |
| 2800 } | |
| 2801 } | |
| 2802 | |
| 2803 bool ConcurrentMark::should_yield() { | |
| 2804 return cmThread()->should_yield(); | |
| 2805 } | |
| 2806 | |
| 2807 bool ConcurrentMark::containing_card_is_marked(void* p) { | |
| 2808 size_t offset = pointer_delta(p, _g1h->reserved_region().start(), 1); | |
| 2809 return _card_bm.at(offset >> CardTableModRefBS::card_shift); | |
| 2810 } | |
| 2811 | |
| 2812 bool ConcurrentMark::containing_cards_are_marked(void* start, | |
| 2813 void* last) { | |
| 2814 return | |
| 2815 containing_card_is_marked(start) && | |
| 2816 containing_card_is_marked(last); | |
| 2817 } | |
| 2818 | |
| 2819 #ifndef PRODUCT | |
| 2820 // for debugging purposes | |
| 2821 void ConcurrentMark::print_finger() { | |
| 2822 gclog_or_tty->print_cr("heap ["PTR_FORMAT", "PTR_FORMAT"), global finger = "PTR_FORMAT, | |
| 2823 _heap_start, _heap_end, _finger); | |
| 2824 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 2825 gclog_or_tty->print(" %d: "PTR_FORMAT, i, _tasks[i]->finger()); | |
| 2826 } | |
| 2827 gclog_or_tty->print_cr(""); | |
| 2828 } | |
| 2829 #endif | |
| 2830 | |
| 2831 // Closure for iteration over bitmaps | |
| 2832 class CMBitMapClosure : public BitMapClosure { | |
| 2833 private: | |
| 2834 // the bitmap that is being iterated over | |
| 2835 CMBitMap* _nextMarkBitMap; | |
| 2836 ConcurrentMark* _cm; | |
| 2837 CMTask* _task; | |
| 2838 // true if we're scanning a heap region claimed by the task (so that | |
| 2839 // we move the finger along), false if we're not, i.e. currently when | |
| 2840 // scanning a heap region popped from the region stack (so that we | |
| 2841 // do not move the task finger along; it'd be a mistake if we did so). | |
| 2842 bool _scanning_heap_region; | |
| 2843 | |
| 2844 public: | |
| 2845 CMBitMapClosure(CMTask *task, | |
| 2846 ConcurrentMark* cm, | |
| 2847 CMBitMap* nextMarkBitMap) | |
| 2848 : _task(task), _cm(cm), _nextMarkBitMap(nextMarkBitMap) { } | |
| 2849 | |
| 2850 void set_scanning_heap_region(bool scanning_heap_region) { | |
| 2851 _scanning_heap_region = scanning_heap_region; | |
| 2852 } | |
| 2853 | |
| 2854 bool do_bit(size_t offset) { | |
| 2855 HeapWord* addr = _nextMarkBitMap->offsetToHeapWord(offset); | |
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2856 assert(_nextMarkBitMap->isMarked(addr), "invariant"); |
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2857 assert( addr < _cm->finger(), "invariant"); |
| 342 | 2858 |
| 2859 if (_scanning_heap_region) { | |
| 2860 statsOnly( _task->increase_objs_found_on_bitmap() ); | |
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2861 assert(addr >= _task->finger(), "invariant"); |
| 342 | 2862 // We move that task's local finger along. |
| 2863 _task->move_finger_to(addr); | |
| 2864 } else { | |
| 2865 // We move the task's region finger along. | |
| 2866 _task->move_region_finger_to(addr); | |
| 2867 } | |
| 2868 | |
| 2869 _task->scan_object(oop(addr)); | |
| 2870 // we only partially drain the local queue and global stack | |
| 2871 _task->drain_local_queue(true); | |
| 2872 _task->drain_global_stack(true); | |
| 2873 | |
| 2874 // if the has_aborted flag has been raised, we need to bail out of | |
| 2875 // the iteration | |
| 2876 return !_task->has_aborted(); | |
| 2877 } | |
| 2878 }; | |
| 2879 | |
| 2880 // Closure for iterating over objects, currently only used for | |
| 2881 // processing SATB buffers. | |
| 2882 class CMObjectClosure : public ObjectClosure { | |
| 2883 private: | |
| 2884 CMTask* _task; | |
| 2885 | |
| 2886 public: | |
| 2887 void do_object(oop obj) { | |
| 2888 _task->deal_with_reference(obj); | |
| 2889 } | |
| 2890 | |
| 2891 CMObjectClosure(CMTask* task) : _task(task) { } | |
| 2892 }; | |
| 2893 | |
| 2894 // Closure for iterating over object fields | |
| 2895 class CMOopClosure : public OopClosure { | |
| 2896 private: | |
| 2897 G1CollectedHeap* _g1h; | |
| 2898 ConcurrentMark* _cm; | |
| 2899 CMTask* _task; | |
| 2900 | |
| 2901 public: | |
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2902 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2903 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2904 |
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2905 template <class T> void do_oop_work(T* p) { |
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2906 assert(_g1h->is_in_g1_reserved((HeapWord*) p), "invariant"); |
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2907 assert(!_g1h->heap_region_containing((HeapWord*) p)->is_on_free_list(), |
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2908 "invariant"); |
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2909 |
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2910 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2911 if (_cm->verbose_high()) |
| 2912 gclog_or_tty->print_cr("[%d] we're looking at location " | |
| 2913 "*"PTR_FORMAT" = "PTR_FORMAT, | |
| 2914 _task->task_id(), p, (void*) obj); | |
| 2915 _task->deal_with_reference(obj); | |
| 2916 } | |
| 2917 | |
| 2918 CMOopClosure(G1CollectedHeap* g1h, | |
| 2919 ConcurrentMark* cm, | |
| 2920 CMTask* task) | |
| 2921 : _g1h(g1h), _cm(cm), _task(task) { } | |
| 2922 }; | |
| 2923 | |
| 2924 void CMTask::setup_for_region(HeapRegion* hr) { | |
|
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2925 // Separated the asserts so that we know which one fires. |
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2926 assert(hr != NULL, |
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2927 "claim_region() should have filtered out continues humongous regions"); |
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2928 assert(!hr->continuesHumongous(), |
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2929 "claim_region() should have filtered out continues humongous regions"); |
| 342 | 2930 |
| 2931 if (_cm->verbose_low()) | |
| 2932 gclog_or_tty->print_cr("[%d] setting up for region "PTR_FORMAT, | |
| 2933 _task_id, hr); | |
| 2934 | |
| 2935 _curr_region = hr; | |
| 2936 _finger = hr->bottom(); | |
| 2937 update_region_limit(); | |
| 2938 } | |
| 2939 | |
| 2940 void CMTask::update_region_limit() { | |
| 2941 HeapRegion* hr = _curr_region; | |
| 2942 HeapWord* bottom = hr->bottom(); | |
| 2943 HeapWord* limit = hr->next_top_at_mark_start(); | |
| 2944 | |
| 2945 if (limit == bottom) { | |
| 2946 if (_cm->verbose_low()) | |
| 2947 gclog_or_tty->print_cr("[%d] found an empty region " | |
| 2948 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 2949 _task_id, bottom, limit); | |
| 2950 // The region was collected underneath our feet. | |
| 2951 // We set the finger to bottom to ensure that the bitmap | |
| 2952 // iteration that will follow this will not do anything. | |
| 2953 // (this is not a condition that holds when we set the region up, | |
| 2954 // as the region is not supposed to be empty in the first place) | |
| 2955 _finger = bottom; | |
| 2956 } else if (limit >= _region_limit) { | |
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2957 assert(limit >= _finger, "peace of mind"); |
| 342 | 2958 } else { |
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2959 assert(limit < _region_limit, "only way to get here"); |
| 342 | 2960 // This can happen under some pretty unusual circumstances. An |
| 2961 // evacuation pause empties the region underneath our feet (NTAMS | |
| 2962 // at bottom). We then do some allocation in the region (NTAMS | |
| 2963 // stays at bottom), followed by the region being used as a GC | |
| 2964 // alloc region (NTAMS will move to top() and the objects | |
| 2965 // originally below it will be grayed). All objects now marked in | |
| 2966 // the region are explicitly grayed, if below the global finger, | |
| 2967 // and we do not need in fact to scan anything else. So, we simply | |
| 2968 // set _finger to be limit to ensure that the bitmap iteration | |
| 2969 // doesn't do anything. | |
| 2970 _finger = limit; | |
| 2971 } | |
| 2972 | |
| 2973 _region_limit = limit; | |
| 2974 } | |
| 2975 | |
| 2976 void CMTask::giveup_current_region() { | |
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2977 assert(_curr_region != NULL, "invariant"); |
| 342 | 2978 if (_cm->verbose_low()) |
| 2979 gclog_or_tty->print_cr("[%d] giving up region "PTR_FORMAT, | |
| 2980 _task_id, _curr_region); | |
| 2981 clear_region_fields(); | |
| 2982 } | |
| 2983 | |
| 2984 void CMTask::clear_region_fields() { | |
| 2985 // Values for these three fields that indicate that we're not | |
| 2986 // holding on to a region. | |
| 2987 _curr_region = NULL; | |
| 2988 _finger = NULL; | |
| 2989 _region_limit = NULL; | |
| 2990 | |
| 2991 _region_finger = NULL; | |
| 2992 } | |
| 2993 | |
| 2994 void CMTask::reset(CMBitMap* nextMarkBitMap) { | |
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2995 guarantee(nextMarkBitMap != NULL, "invariant"); |
| 342 | 2996 |
| 2997 if (_cm->verbose_low()) | |
| 2998 gclog_or_tty->print_cr("[%d] resetting", _task_id); | |
| 2999 | |
| 3000 _nextMarkBitMap = nextMarkBitMap; | |
| 3001 clear_region_fields(); | |
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3002 assert(_aborted_region.is_empty(), "should have been cleared"); |
| 342 | 3003 |
| 3004 _calls = 0; | |
| 3005 _elapsed_time_ms = 0.0; | |
| 3006 _termination_time_ms = 0.0; | |
| 3007 _termination_start_time_ms = 0.0; | |
| 3008 | |
| 3009 #if _MARKING_STATS_ | |
| 3010 _local_pushes = 0; | |
| 3011 _local_pops = 0; | |
| 3012 _local_max_size = 0; | |
| 3013 _objs_scanned = 0; | |
| 3014 _global_pushes = 0; | |
| 3015 _global_pops = 0; | |
| 3016 _global_max_size = 0; | |
| 3017 _global_transfers_to = 0; | |
| 3018 _global_transfers_from = 0; | |
| 3019 _region_stack_pops = 0; | |
| 3020 _regions_claimed = 0; | |
| 3021 _objs_found_on_bitmap = 0; | |
| 3022 _satb_buffers_processed = 0; | |
| 3023 _steal_attempts = 0; | |
| 3024 _steals = 0; | |
| 3025 _aborted = 0; | |
| 3026 _aborted_overflow = 0; | |
| 3027 _aborted_cm_aborted = 0; | |
| 3028 _aborted_yield = 0; | |
| 3029 _aborted_timed_out = 0; | |
| 3030 _aborted_satb = 0; | |
| 3031 _aborted_termination = 0; | |
| 3032 #endif // _MARKING_STATS_ | |
| 3033 } | |
| 3034 | |
| 3035 bool CMTask::should_exit_termination() { | |
| 3036 regular_clock_call(); | |
| 3037 // This is called when we are in the termination protocol. We should | |
| 3038 // quit if, for some reason, this task wants to abort or the global | |
| 3039 // stack is not empty (this means that we can get work from it). | |
| 3040 return !_cm->mark_stack_empty() || has_aborted(); | |
| 3041 } | |
| 3042 | |
| 3043 // This determines whether the method below will check both the local | |
| 3044 // and global fingers when determining whether to push on the stack a | |
| 3045 // gray object (value 1) or whether it will only check the global one | |
| 3046 // (value 0). The tradeoffs are that the former will be a bit more | |
| 3047 // accurate and possibly push less on the stack, but it might also be | |
| 3048 // a little bit slower. | |
| 3049 | |
| 3050 #define _CHECK_BOTH_FINGERS_ 1 | |
| 3051 | |
| 3052 void CMTask::deal_with_reference(oop obj) { | |
| 3053 if (_cm->verbose_high()) | |
| 3054 gclog_or_tty->print_cr("[%d] we're dealing with reference = "PTR_FORMAT, | |
| 3055 _task_id, (void*) obj); | |
| 3056 | |
| 3057 ++_refs_reached; | |
| 3058 | |
| 3059 HeapWord* objAddr = (HeapWord*) obj; | |
|
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3060 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 3061 if (_g1h->is_in_g1_reserved(objAddr)) { |
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3062 assert(obj != NULL, "is_in_g1_reserved should ensure this"); |
| 342 | 3063 HeapRegion* hr = _g1h->heap_region_containing(obj); |
| 3064 if (_g1h->is_obj_ill(obj, hr)) { | |
| 3065 if (_cm->verbose_high()) | |
| 3066 gclog_or_tty->print_cr("[%d] "PTR_FORMAT" is not considered marked", | |
| 3067 _task_id, (void*) obj); | |
| 3068 | |
| 3069 // we need to mark it first | |
| 3070 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 3071 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 3072 // CAS done in parMark(objAddr) above | |
| 3073 HeapWord* global_finger = _cm->finger(); | |
| 3074 | |
| 3075 #if _CHECK_BOTH_FINGERS_ | |
| 3076 // we will check both the local and global fingers | |
| 3077 | |
| 3078 if (_finger != NULL && objAddr < _finger) { | |
| 3079 if (_cm->verbose_high()) | |
| 3080 gclog_or_tty->print_cr("[%d] below the local finger ("PTR_FORMAT"), " | |
| 3081 "pushing it", _task_id, _finger); | |
| 3082 push(obj); | |
| 3083 } else if (_curr_region != NULL && objAddr < _region_limit) { | |
| 3084 // do nothing | |
| 3085 } else if (objAddr < global_finger) { | |
| 3086 // Notice that the global finger might be moving forward | |
| 3087 // concurrently. This is not a problem. In the worst case, we | |
| 3088 // mark the object while it is above the global finger and, by | |
| 3089 // the time we read the global finger, it has moved forward | |
| 3090 // passed this object. In this case, the object will probably | |
| 3091 // be visited when a task is scanning the region and will also | |
| 3092 // be pushed on the stack. So, some duplicate work, but no | |
| 3093 // correctness problems. | |
| 3094 | |
| 3095 if (_cm->verbose_high()) | |
| 3096 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3097 "("PTR_FORMAT"), pushing it", | |
| 3098 _task_id, global_finger); | |
| 3099 push(obj); | |
| 3100 } else { | |
| 3101 // do nothing | |
| 3102 } | |
| 3103 #else // _CHECK_BOTH_FINGERS_ | |
| 3104 // we will only check the global finger | |
| 3105 | |
| 3106 if (objAddr < global_finger) { | |
| 3107 // see long comment above | |
| 3108 | |
| 3109 if (_cm->verbose_high()) | |
| 3110 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3111 "("PTR_FORMAT"), pushing it", | |
| 3112 _task_id, global_finger); | |
| 3113 push(obj); | |
| 3114 } | |
| 3115 #endif // _CHECK_BOTH_FINGERS_ | |
| 3116 } | |
| 3117 } | |
| 3118 } | |
| 3119 } | |
| 3120 | |
| 3121 void CMTask::push(oop obj) { | |
| 3122 HeapWord* objAddr = (HeapWord*) obj; | |
|
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3123 assert(_g1h->is_in_g1_reserved(objAddr), "invariant"); |
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3124 assert(!_g1h->heap_region_containing(objAddr)->is_on_free_list(), |
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3125 "invariant"); |
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3126 assert(!_g1h->is_obj_ill(obj), "invariant"); |
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3127 assert(_nextMarkBitMap->isMarked(objAddr), "invariant"); |
| 342 | 3128 |
| 3129 if (_cm->verbose_high()) | |
| 3130 gclog_or_tty->print_cr("[%d] pushing "PTR_FORMAT, _task_id, (void*) obj); | |
| 3131 | |
| 3132 if (!_task_queue->push(obj)) { | |
| 3133 // The local task queue looks full. We need to push some entries | |
| 3134 // to the global stack. | |
| 3135 | |
| 3136 if (_cm->verbose_medium()) | |
| 3137 gclog_or_tty->print_cr("[%d] task queue overflow, " | |
| 3138 "moving entries to the global stack", | |
| 3139 _task_id); | |
| 3140 move_entries_to_global_stack(); | |
| 3141 | |
| 3142 // this should succeed since, even if we overflow the global | |
| 3143 // stack, we should have definitely removed some entries from the | |
| 3144 // local queue. So, there must be space on it. | |
| 3145 bool success = _task_queue->push(obj); | |
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3146 assert(success, "invariant"); |
| 342 | 3147 } |
| 3148 | |
| 3149 statsOnly( int tmp_size = _task_queue->size(); | |
| 3150 if (tmp_size > _local_max_size) | |
| 3151 _local_max_size = tmp_size; | |
| 3152 ++_local_pushes ); | |
| 3153 } | |
| 3154 | |
| 3155 void CMTask::reached_limit() { | |
|
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3156 assert(_words_scanned >= _words_scanned_limit || |
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3157 _refs_reached >= _refs_reached_limit , |
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3158 "shouldn't have been called otherwise"); |
| 342 | 3159 regular_clock_call(); |
| 3160 } | |
| 3161 | |
| 3162 void CMTask::regular_clock_call() { | |
| 3163 if (has_aborted()) | |
| 3164 return; | |
| 3165 | |
| 3166 // First, we need to recalculate the words scanned and refs reached | |
| 3167 // limits for the next clock call. | |
| 3168 recalculate_limits(); | |
| 3169 | |
| 3170 // During the regular clock call we do the following | |
| 3171 | |
| 3172 // (1) If an overflow has been flagged, then we abort. | |
| 3173 if (_cm->has_overflown()) { | |
| 3174 set_has_aborted(); | |
| 3175 return; | |
| 3176 } | |
| 3177 | |
| 3178 // If we are not concurrent (i.e. we're doing remark) we don't need | |
| 3179 // to check anything else. The other steps are only needed during | |
| 3180 // the concurrent marking phase. | |
| 3181 if (!concurrent()) | |
| 3182 return; | |
| 3183 | |
| 3184 // (2) If marking has been aborted for Full GC, then we also abort. | |
| 3185 if (_cm->has_aborted()) { | |
| 3186 set_has_aborted(); | |
| 3187 statsOnly( ++_aborted_cm_aborted ); | |
| 3188 return; | |
| 3189 } | |
| 3190 | |
| 3191 double curr_time_ms = os::elapsedVTime() * 1000.0; | |
| 3192 | |
| 3193 // (3) If marking stats are enabled, then we update the step history. | |
| 3194 #if _MARKING_STATS_ | |
| 3195 if (_words_scanned >= _words_scanned_limit) | |
| 3196 ++_clock_due_to_scanning; | |
| 3197 if (_refs_reached >= _refs_reached_limit) | |
| 3198 ++_clock_due_to_marking; | |
| 3199 | |
| 3200 double last_interval_ms = curr_time_ms - _interval_start_time_ms; | |
| 3201 _interval_start_time_ms = curr_time_ms; | |
| 3202 _all_clock_intervals_ms.add(last_interval_ms); | |
| 3203 | |
| 3204 if (_cm->verbose_medium()) { | |
| 3205 gclog_or_tty->print_cr("[%d] regular clock, interval = %1.2lfms, " | |
| 3206 "scanned = %d%s, refs reached = %d%s", | |
| 3207 _task_id, last_interval_ms, | |
| 3208 _words_scanned, | |
| 3209 (_words_scanned >= _words_scanned_limit) ? " (*)" : "", | |
| 3210 _refs_reached, | |
| 3211 (_refs_reached >= _refs_reached_limit) ? " (*)" : ""); | |
| 3212 } | |
| 3213 #endif // _MARKING_STATS_ | |
| 3214 | |
| 3215 // (4) We check whether we should yield. If we have to, then we abort. | |
| 3216 if (_cm->should_yield()) { | |
| 3217 // We should yield. To do this we abort the task. The caller is | |
| 3218 // responsible for yielding. | |
| 3219 set_has_aborted(); | |
| 3220 statsOnly( ++_aborted_yield ); | |
| 3221 return; | |
| 3222 } | |
| 3223 | |
| 3224 // (5) We check whether we've reached our time quota. If we have, | |
| 3225 // then we abort. | |
| 3226 double elapsed_time_ms = curr_time_ms - _start_time_ms; | |
| 3227 if (elapsed_time_ms > _time_target_ms) { | |
| 3228 set_has_aborted(); | |
| 3229 _has_aborted_timed_out = true; | |
| 3230 statsOnly( ++_aborted_timed_out ); | |
| 3231 return; | |
| 3232 } | |
| 3233 | |
| 3234 // (6) Finally, we check whether there are enough completed STAB | |
| 3235 // buffers available for processing. If there are, we abort. | |
| 3236 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 3237 if (!_draining_satb_buffers && satb_mq_set.process_completed_buffers()) { | |
| 3238 if (_cm->verbose_low()) | |
| 3239 gclog_or_tty->print_cr("[%d] aborting to deal with pending SATB buffers", | |
| 3240 _task_id); | |
| 3241 // we do need to process SATB buffers, we'll abort and restart | |
| 3242 // the marking task to do so | |
| 3243 set_has_aborted(); | |
| 3244 statsOnly( ++_aborted_satb ); | |
| 3245 return; | |
| 3246 } | |
| 3247 } | |
| 3248 | |
| 3249 void CMTask::recalculate_limits() { | |
| 3250 _real_words_scanned_limit = _words_scanned + words_scanned_period; | |
| 3251 _words_scanned_limit = _real_words_scanned_limit; | |
| 3252 | |
| 3253 _real_refs_reached_limit = _refs_reached + refs_reached_period; | |
| 3254 _refs_reached_limit = _real_refs_reached_limit; | |
| 3255 } | |
| 3256 | |
| 3257 void CMTask::decrease_limits() { | |
| 3258 // This is called when we believe that we're going to do an infrequent | |
| 3259 // operation which will increase the per byte scanned cost (i.e. move | |
| 3260 // entries to/from the global stack). It basically tries to decrease the | |
| 3261 // scanning limit so that the clock is called earlier. | |
| 3262 | |
| 3263 if (_cm->verbose_medium()) | |
| 3264 gclog_or_tty->print_cr("[%d] decreasing limits", _task_id); | |
| 3265 | |
| 3266 _words_scanned_limit = _real_words_scanned_limit - | |
| 3267 3 * words_scanned_period / 4; | |
| 3268 _refs_reached_limit = _real_refs_reached_limit - | |
| 3269 3 * refs_reached_period / 4; | |
| 3270 } | |
| 3271 | |
| 3272 void CMTask::move_entries_to_global_stack() { | |
| 3273 // local array where we'll store the entries that will be popped | |
| 3274 // from the local queue | |
| 3275 oop buffer[global_stack_transfer_size]; | |
| 3276 | |
| 3277 int n = 0; | |
| 3278 oop obj; | |
| 3279 while (n < global_stack_transfer_size && _task_queue->pop_local(obj)) { | |
| 3280 buffer[n] = obj; | |
| 3281 ++n; | |
| 3282 } | |
| 3283 | |
| 3284 if (n > 0) { | |
| 3285 // we popped at least one entry from the local queue | |
| 3286 | |
| 3287 statsOnly( ++_global_transfers_to; _local_pops += n ); | |
| 3288 | |
| 3289 if (!_cm->mark_stack_push(buffer, n)) { | |
| 3290 if (_cm->verbose_low()) | |
| 3291 gclog_or_tty->print_cr("[%d] aborting due to global stack overflow", _task_id); | |
| 3292 set_has_aborted(); | |
| 3293 } else { | |
| 3294 // the transfer was successful | |
| 3295 | |
| 3296 if (_cm->verbose_medium()) | |
| 3297 gclog_or_tty->print_cr("[%d] pushed %d entries to the global stack", | |
| 3298 _task_id, n); | |
| 3299 statsOnly( int tmp_size = _cm->mark_stack_size(); | |
| 3300 if (tmp_size > _global_max_size) | |
| 3301 _global_max_size = tmp_size; | |
| 3302 _global_pushes += n ); | |
| 3303 } | |
| 3304 } | |
| 3305 | |
| 3306 // this operation was quite expensive, so decrease the limits | |
| 3307 decrease_limits(); | |
| 3308 } | |
| 3309 | |
| 3310 void CMTask::get_entries_from_global_stack() { | |
| 3311 // local array where we'll store the entries that will be popped | |
| 3312 // from the global stack. | |
| 3313 oop buffer[global_stack_transfer_size]; | |
| 3314 int n; | |
| 3315 _cm->mark_stack_pop(buffer, global_stack_transfer_size, &n); | |
|
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3316 assert(n <= global_stack_transfer_size, |
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3317 "we should not pop more than the given limit"); |
| 342 | 3318 if (n > 0) { |
| 3319 // yes, we did actually pop at least one entry | |
| 3320 | |
| 3321 statsOnly( ++_global_transfers_from; _global_pops += n ); | |
| 3322 if (_cm->verbose_medium()) | |
| 3323 gclog_or_tty->print_cr("[%d] popped %d entries from the global stack", | |
| 3324 _task_id, n); | |
| 3325 for (int i = 0; i < n; ++i) { | |
| 3326 bool success = _task_queue->push(buffer[i]); | |
| 3327 // We only call this when the local queue is empty or under a | |
| 3328 // given target limit. So, we do not expect this push to fail. | |
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3329 assert(success, "invariant"); |
| 342 | 3330 } |
| 3331 | |
| 3332 statsOnly( int tmp_size = _task_queue->size(); | |
| 3333 if (tmp_size > _local_max_size) | |
| 3334 _local_max_size = tmp_size; | |
| 3335 _local_pushes += n ); | |
| 3336 } | |
| 3337 | |
| 3338 // this operation was quite expensive, so decrease the limits | |
| 3339 decrease_limits(); | |
| 3340 } | |
| 3341 | |
| 3342 void CMTask::drain_local_queue(bool partially) { | |
| 3343 if (has_aborted()) | |
| 3344 return; | |
| 3345 | |
| 3346 // Decide what the target size is, depending whether we're going to | |
| 3347 // drain it partially (so that other tasks can steal if they run out | |
| 3348 // of things to do) or totally (at the very end). | |
| 3349 size_t target_size; | |
| 3350 if (partially) | |
| 3351 target_size = MIN2((size_t)_task_queue->max_elems()/3, GCDrainStackTargetSize); | |
| 3352 else | |
| 3353 target_size = 0; | |
| 3354 | |
| 3355 if (_task_queue->size() > target_size) { | |
| 3356 if (_cm->verbose_high()) | |
| 3357 gclog_or_tty->print_cr("[%d] draining local queue, target size = %d", | |
| 3358 _task_id, target_size); | |
| 3359 | |
| 3360 oop obj; | |
| 3361 bool ret = _task_queue->pop_local(obj); | |
| 3362 while (ret) { | |
| 3363 statsOnly( ++_local_pops ); | |
| 3364 | |
| 3365 if (_cm->verbose_high()) | |
| 3366 gclog_or_tty->print_cr("[%d] popped "PTR_FORMAT, _task_id, | |
| 3367 (void*) obj); | |
| 3368 | |
|
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|
3369 assert(_g1h->is_in_g1_reserved((HeapWord*) obj), "invariant" ); |
|
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3370 assert(!_g1h->heap_region_containing(obj)->is_on_free_list(), |
|
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|
3371 "invariant"); |
| 342 | 3372 |
| 3373 scan_object(obj); | |
| 3374 | |
| 3375 if (_task_queue->size() <= target_size || has_aborted()) | |
| 3376 ret = false; | |
| 3377 else | |
| 3378 ret = _task_queue->pop_local(obj); | |
| 3379 } | |
| 3380 | |
| 3381 if (_cm->verbose_high()) | |
| 3382 gclog_or_tty->print_cr("[%d] drained local queue, size = %d", | |
| 3383 _task_id, _task_queue->size()); | |
| 3384 } | |
| 3385 } | |
| 3386 | |
| 3387 void CMTask::drain_global_stack(bool partially) { | |
| 3388 if (has_aborted()) | |
| 3389 return; | |
| 3390 | |
| 3391 // We have a policy to drain the local queue before we attempt to | |
| 3392 // drain the global stack. | |
|
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|
3393 assert(partially || _task_queue->size() == 0, "invariant"); |
| 342 | 3394 |
| 3395 // Decide what the target size is, depending whether we're going to | |
| 3396 // drain it partially (so that other tasks can steal if they run out | |
| 3397 // of things to do) or totally (at the very end). Notice that, | |
| 3398 // because we move entries from the global stack in chunks or | |
| 3399 // because another task might be doing the same, we might in fact | |
| 3400 // drop below the target. But, this is not a problem. | |
| 3401 size_t target_size; | |
| 3402 if (partially) | |
| 3403 target_size = _cm->partial_mark_stack_size_target(); | |
| 3404 else | |
| 3405 target_size = 0; | |
| 3406 | |
| 3407 if (_cm->mark_stack_size() > target_size) { | |
| 3408 if (_cm->verbose_low()) | |
| 3409 gclog_or_tty->print_cr("[%d] draining global_stack, target size %d", | |
| 3410 _task_id, target_size); | |
| 3411 | |
| 3412 while (!has_aborted() && _cm->mark_stack_size() > target_size) { | |
| 3413 get_entries_from_global_stack(); | |
| 3414 drain_local_queue(partially); | |
| 3415 } | |
| 3416 | |
| 3417 if (_cm->verbose_low()) | |
| 3418 gclog_or_tty->print_cr("[%d] drained global stack, size = %d", | |
| 3419 _task_id, _cm->mark_stack_size()); | |
| 3420 } | |
| 3421 } | |
| 3422 | |
| 3423 // SATB Queue has several assumptions on whether to call the par or | |
| 3424 // non-par versions of the methods. this is why some of the code is | |
| 3425 // replicated. We should really get rid of the single-threaded version | |
| 3426 // of the code to simplify things. | |
| 3427 void CMTask::drain_satb_buffers() { | |
| 3428 if (has_aborted()) | |
| 3429 return; | |
| 3430 | |
| 3431 // We set this so that the regular clock knows that we're in the | |
| 3432 // middle of draining buffers and doesn't set the abort flag when it | |
| 3433 // notices that SATB buffers are available for draining. It'd be | |
| 3434 // very counter productive if it did that. :-) | |
| 3435 _draining_satb_buffers = true; | |
| 3436 | |
| 3437 CMObjectClosure oc(this); | |
| 3438 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
|
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|
3439 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3440 satb_mq_set.set_par_closure(_task_id, &oc); |
| 3441 else | |
| 3442 satb_mq_set.set_closure(&oc); | |
| 3443 | |
| 3444 // This keeps claiming and applying the closure to completed buffers | |
| 3445 // until we run out of buffers or we need to abort. | |
|
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|
3446 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 3447 while (!has_aborted() && |
| 3448 satb_mq_set.par_apply_closure_to_completed_buffer(_task_id)) { | |
| 3449 if (_cm->verbose_medium()) | |
| 3450 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3451 statsOnly( ++_satb_buffers_processed ); | |
| 3452 regular_clock_call(); | |
| 3453 } | |
| 3454 } else { | |
| 3455 while (!has_aborted() && | |
| 3456 satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 3457 if (_cm->verbose_medium()) | |
| 3458 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3459 statsOnly( ++_satb_buffers_processed ); | |
| 3460 regular_clock_call(); | |
| 3461 } | |
| 3462 } | |
| 3463 | |
| 3464 if (!concurrent() && !has_aborted()) { | |
| 3465 // We should only do this during remark. | |
|
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|
3466 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3467 satb_mq_set.par_iterate_closure_all_threads(_task_id); |
| 3468 else | |
| 3469 satb_mq_set.iterate_closure_all_threads(); | |
| 3470 } | |
| 3471 | |
| 3472 _draining_satb_buffers = false; | |
| 3473 | |
|
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|
3474 assert(has_aborted() || |
|
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|
3475 concurrent() || |
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|
3476 satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 3477 |
|
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|
3478 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3479 satb_mq_set.set_par_closure(_task_id, NULL); |
| 3480 else | |
| 3481 satb_mq_set.set_closure(NULL); | |
| 3482 | |
| 3483 // again, this was a potentially expensive operation, decrease the | |
| 3484 // limits to get the regular clock call early | |
| 3485 decrease_limits(); | |
| 3486 } | |
| 3487 | |
| 3488 void CMTask::drain_region_stack(BitMapClosure* bc) { | |
| 3489 if (has_aborted()) | |
| 3490 return; | |
| 3491 | |
|
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|
3492 assert(_region_finger == NULL, |
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|
3493 "it should be NULL when we're not scanning a region"); |
| 342 | 3494 |
|
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|
3495 if (!_cm->region_stack_empty() || !_aborted_region.is_empty()) { |
| 342 | 3496 if (_cm->verbose_low()) |
| 3497 gclog_or_tty->print_cr("[%d] draining region stack, size = %d", | |
| 3498 _task_id, _cm->region_stack_size()); | |
| 3499 | |
|
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|
3500 MemRegion mr; |
|
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|
3501 |
|
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|
3502 if (!_aborted_region.is_empty()) { |
|
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|
3503 mr = _aborted_region; |
|
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|
3504 _aborted_region = MemRegion(); |
|
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|
3505 |
|
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|
3506 if (_cm->verbose_low()) |
|
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|
3507 gclog_or_tty->print_cr("[%d] scanning aborted region [ " PTR_FORMAT ", " PTR_FORMAT " )", |
|
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|
3508 _task_id, mr.start(), mr.end()); |
|
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|
3509 } else { |
|
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|
3510 mr = _cm->region_stack_pop_lock_free(); |
|
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|
3511 // it returns MemRegion() if the pop fails |
|
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|
3512 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); |
|
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|
3513 } |
| 342 | 3514 |
| 3515 while (mr.start() != NULL) { | |
| 3516 if (_cm->verbose_medium()) | |
| 3517 gclog_or_tty->print_cr("[%d] we are scanning region " | |
| 3518 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 3519 _task_id, mr.start(), mr.end()); | |
|
1835
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|
3520 |
|
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3521 assert(mr.end() <= _cm->finger(), |
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|
3522 "otherwise the region shouldn't be on the stack"); |
| 342 | 3523 assert(!mr.is_empty(), "Only non-empty regions live on the region stack"); |
| 3524 if (_nextMarkBitMap->iterate(bc, mr)) { | |
|
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|
3525 assert(!has_aborted(), |
|
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|
3526 "cannot abort the task without aborting the bitmap iteration"); |
| 342 | 3527 |
| 3528 // We finished iterating over the region without aborting. | |
| 3529 regular_clock_call(); | |
| 3530 if (has_aborted()) | |
| 3531 mr = MemRegion(); | |
| 3532 else { | |
|
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|
3533 mr = _cm->region_stack_pop_lock_free(); |
| 342 | 3534 // it returns MemRegion() if the pop fails |
| 3535 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); | |
| 3536 } | |
| 3537 } else { | |
|
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|
3538 assert(has_aborted(), "currently the only way to do so"); |
| 342 | 3539 |
| 3540 // The only way to abort the bitmap iteration is to return | |
| 3541 // false from the do_bit() method. However, inside the | |
| 3542 // do_bit() method we move the _region_finger to point to the | |
| 3543 // object currently being looked at. So, if we bail out, we | |
| 3544 // have definitely set _region_finger to something non-null. | |
|
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|
3545 assert(_region_finger != NULL, "invariant"); |
| 342 | 3546 |
|
1835
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|
3547 // Make sure that any previously aborted region has been |
|
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|
3548 // cleared. |
|
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|
3549 assert(_aborted_region.is_empty(), "aborted region not cleared"); |
|
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|
3550 |
| 342 | 3551 // The iteration was actually aborted. So now _region_finger |
| 3552 // points to the address of the object we last scanned. If we | |
| 3553 // leave it there, when we restart this task, we will rescan | |
| 3554 // the object. It is easy to avoid this. We move the finger by | |
| 3555 // enough to point to the next possible object header (the | |
| 3556 // bitmap knows by how much we need to move it as it knows its | |
| 3557 // granularity). | |
| 3558 MemRegion newRegion = | |
| 3559 MemRegion(_nextMarkBitMap->nextWord(_region_finger), mr.end()); | |
| 3560 | |
| 3561 if (!newRegion.is_empty()) { | |
| 3562 if (_cm->verbose_low()) { | |
|
1835
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|
3563 gclog_or_tty->print_cr("[%d] recording unscanned region" |
|
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|
3564 "[" PTR_FORMAT "," PTR_FORMAT ") in CMTask", |
| 342 | 3565 _task_id, |
| 3566 newRegion.start(), newRegion.end()); | |
| 3567 } | |
|
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|
3568 // Now record the part of the region we didn't scan to |
|
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|
3569 // make sure this task scans it later. |
|
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|
3570 _aborted_region = newRegion; |
| 342 | 3571 } |
| 3572 // break from while | |
| 3573 mr = MemRegion(); | |
| 3574 } | |
| 3575 _region_finger = NULL; | |
| 3576 } | |
| 3577 | |
| 3578 if (_cm->verbose_low()) | |
| 3579 gclog_or_tty->print_cr("[%d] drained region stack, size = %d", | |
| 3580 _task_id, _cm->region_stack_size()); | |
| 3581 } | |
| 3582 } | |
| 3583 | |
| 3584 void CMTask::print_stats() { | |
| 3585 gclog_or_tty->print_cr("Marking Stats, task = %d, calls = %d", | |
| 3586 _task_id, _calls); | |
| 3587 gclog_or_tty->print_cr(" Elapsed time = %1.2lfms, Termination time = %1.2lfms", | |
| 3588 _elapsed_time_ms, _termination_time_ms); | |
| 3589 gclog_or_tty->print_cr(" Step Times (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3590 _step_times_ms.num(), _step_times_ms.avg(), | |
| 3591 _step_times_ms.sd()); | |
| 3592 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3593 _step_times_ms.maximum(), _step_times_ms.sum()); | |
| 3594 | |
| 3595 #if _MARKING_STATS_ | |
| 3596 gclog_or_tty->print_cr(" Clock Intervals (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3597 _all_clock_intervals_ms.num(), _all_clock_intervals_ms.avg(), | |
| 3598 _all_clock_intervals_ms.sd()); | |
| 3599 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3600 _all_clock_intervals_ms.maximum(), | |
| 3601 _all_clock_intervals_ms.sum()); | |
| 3602 gclog_or_tty->print_cr(" Clock Causes (cum): scanning = %d, marking = %d", | |
| 3603 _clock_due_to_scanning, _clock_due_to_marking); | |
| 3604 gclog_or_tty->print_cr(" Objects: scanned = %d, found on the bitmap = %d", | |
| 3605 _objs_scanned, _objs_found_on_bitmap); | |
| 3606 gclog_or_tty->print_cr(" Local Queue: pushes = %d, pops = %d, max size = %d", | |
| 3607 _local_pushes, _local_pops, _local_max_size); | |
| 3608 gclog_or_tty->print_cr(" Global Stack: pushes = %d, pops = %d, max size = %d", | |
| 3609 _global_pushes, _global_pops, _global_max_size); | |
| 3610 gclog_or_tty->print_cr(" transfers to = %d, transfers from = %d", | |
| 3611 _global_transfers_to,_global_transfers_from); | |
| 3612 gclog_or_tty->print_cr(" Regions: claimed = %d, Region Stack: pops = %d", | |
| 3613 _regions_claimed, _region_stack_pops); | |
| 3614 gclog_or_tty->print_cr(" SATB buffers: processed = %d", _satb_buffers_processed); | |
| 3615 gclog_or_tty->print_cr(" Steals: attempts = %d, successes = %d", | |
| 3616 _steal_attempts, _steals); | |
| 3617 gclog_or_tty->print_cr(" Aborted: %d, due to", _aborted); | |
| 3618 gclog_or_tty->print_cr(" overflow: %d, global abort: %d, yield: %d", | |
| 3619 _aborted_overflow, _aborted_cm_aborted, _aborted_yield); | |
| 3620 gclog_or_tty->print_cr(" time out: %d, SATB: %d, termination: %d", | |
| 3621 _aborted_timed_out, _aborted_satb, _aborted_termination); | |
| 3622 #endif // _MARKING_STATS_ | |
| 3623 } | |
| 3624 | |
| 3625 /***************************************************************************** | |
| 3626 | |
| 3627 The do_marking_step(time_target_ms) method is the building block | |
| 3628 of the parallel marking framework. It can be called in parallel | |
| 3629 with other invocations of do_marking_step() on different tasks | |
| 3630 (but only one per task, obviously) and concurrently with the | |
| 3631 mutator threads, or during remark, hence it eliminates the need | |
| 3632 for two versions of the code. When called during remark, it will | |
| 3633 pick up from where the task left off during the concurrent marking | |
| 3634 phase. Interestingly, tasks are also claimable during evacuation | |
| 3635 pauses too, since do_marking_step() ensures that it aborts before | |
| 3636 it needs to yield. | |
| 3637 | |
| 3638 The data structures that is uses to do marking work are the | |
| 3639 following: | |
| 3640 | |
| 3641 (1) Marking Bitmap. If there are gray objects that appear only | |
| 3642 on the bitmap (this happens either when dealing with an overflow | |
| 3643 or when the initial marking phase has simply marked the roots | |
| 3644 and didn't push them on the stack), then tasks claim heap | |
| 3645 regions whose bitmap they then scan to find gray objects. A | |
| 3646 global finger indicates where the end of the last claimed region | |
| 3647 is. A local finger indicates how far into the region a task has | |
| 3648 scanned. The two fingers are used to determine how to gray an | |
| 3649 object (i.e. whether simply marking it is OK, as it will be | |
| 3650 visited by a task in the future, or whether it needs to be also | |
| 3651 pushed on a stack). | |
| 3652 | |
| 3653 (2) Local Queue. The local queue of the task which is accessed | |
| 3654 reasonably efficiently by the task. Other tasks can steal from | |
| 3655 it when they run out of work. Throughout the marking phase, a | |
| 3656 task attempts to keep its local queue short but not totally | |
| 3657 empty, so that entries are available for stealing by other | |
| 3658 tasks. Only when there is no more work, a task will totally | |
| 3659 drain its local queue. | |
| 3660 | |
| 3661 (3) Global Mark Stack. This handles local queue overflow. During | |
| 3662 marking only sets of entries are moved between it and the local | |
| 3663 queues, as access to it requires a mutex and more fine-grain | |
| 3664 interaction with it which might cause contention. If it | |
| 3665 overflows, then the marking phase should restart and iterate | |
| 3666 over the bitmap to identify gray objects. Throughout the marking | |
| 3667 phase, tasks attempt to keep the global mark stack at a small | |
| 3668 length but not totally empty, so that entries are available for | |
| 3669 popping by other tasks. Only when there is no more work, tasks | |
| 3670 will totally drain the global mark stack. | |
| 3671 | |
| 3672 (4) Global Region Stack. Entries on it correspond to areas of | |
| 3673 the bitmap that need to be scanned since they contain gray | |
| 3674 objects. Pushes on the region stack only happen during | |
| 3675 evacuation pauses and typically correspond to areas covered by | |
| 3676 GC LABS. If it overflows, then the marking phase should restart | |
| 3677 and iterate over the bitmap to identify gray objects. Tasks will | |
| 3678 try to totally drain the region stack as soon as possible. | |
| 3679 | |
| 3680 (5) SATB Buffer Queue. This is where completed SATB buffers are | |
| 3681 made available. Buffers are regularly removed from this queue | |
| 3682 and scanned for roots, so that the queue doesn't get too | |
| 3683 long. During remark, all completed buffers are processed, as | |
| 3684 well as the filled in parts of any uncompleted buffers. | |
| 3685 | |
| 3686 The do_marking_step() method tries to abort when the time target | |
| 3687 has been reached. There are a few other cases when the | |
| 3688 do_marking_step() method also aborts: | |
| 3689 | |
| 3690 (1) When the marking phase has been aborted (after a Full GC). | |
| 3691 | |
| 3692 (2) When a global overflow (either on the global stack or the | |
| 3693 region stack) has been triggered. Before the task aborts, it | |
| 3694 will actually sync up with the other tasks to ensure that all | |
| 3695 the marking data structures (local queues, stacks, fingers etc.) | |
| 3696 are re-initialised so that when do_marking_step() completes, | |
| 3697 the marking phase can immediately restart. | |
| 3698 | |
| 3699 (3) When enough completed SATB buffers are available. The | |
| 3700 do_marking_step() method only tries to drain SATB buffers right | |
| 3701 at the beginning. So, if enough buffers are available, the | |
| 3702 marking step aborts and the SATB buffers are processed at | |
| 3703 the beginning of the next invocation. | |
| 3704 | |
| 3705 (4) To yield. when we have to yield then we abort and yield | |
| 3706 right at the end of do_marking_step(). This saves us from a lot | |
| 3707 of hassle as, by yielding we might allow a Full GC. If this | |
| 3708 happens then objects will be compacted underneath our feet, the | |
| 3709 heap might shrink, etc. We save checking for this by just | |
| 3710 aborting and doing the yield right at the end. | |
| 3711 | |
| 3712 From the above it follows that the do_marking_step() method should | |
| 3713 be called in a loop (or, otherwise, regularly) until it completes. | |
| 3714 | |
| 3715 If a marking step completes without its has_aborted() flag being | |
| 3716 true, it means it has completed the current marking phase (and | |
| 3717 also all other marking tasks have done so and have all synced up). | |
| 3718 | |
| 3719 A method called regular_clock_call() is invoked "regularly" (in | |
| 3720 sub ms intervals) throughout marking. It is this clock method that | |
| 3721 checks all the abort conditions which were mentioned above and | |
| 3722 decides when the task should abort. A work-based scheme is used to | |
| 3723 trigger this clock method: when the number of object words the | |
| 3724 marking phase has scanned or the number of references the marking | |
| 3725 phase has visited reach a given limit. Additional invocations to | |
| 3726 the method clock have been planted in a few other strategic places | |
| 3727 too. The initial reason for the clock method was to avoid calling | |
| 3728 vtime too regularly, as it is quite expensive. So, once it was in | |
| 3729 place, it was natural to piggy-back all the other conditions on it | |
| 3730 too and not constantly check them throughout the code. | |
| 3731 | |
| 3732 *****************************************************************************/ | |
| 3733 | |
| 3734 void CMTask::do_marking_step(double time_target_ms) { | |
|
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|
3735 assert(time_target_ms >= 1.0, "minimum granularity is 1ms"); |
|
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|
3736 assert(concurrent() == _cm->concurrent(), "they should be the same"); |
|
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|
3737 |
|
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|
3738 assert(concurrent() || _cm->region_stack_empty(), |
|
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|
3739 "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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|
3740 assert(concurrent() || !_cm->has_aborted_regions(), |
|
4805b9f4779e
6941395: G1: Use only lock-free versions of region stack push() and pop()
johnc
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|
3741 "aborted regions should have been cleared before remark"); |
|
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|
3742 assert(_region_finger == NULL, |
|
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|
3743 "this should be non-null only when a region is being scanned"); |
| 342 | 3744 |
| 3745 G1CollectorPolicy* g1_policy = _g1h->g1_policy(); | |
|
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|
3746 assert(_task_queues != NULL, "invariant"); |
|
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|
3747 assert(_task_queue != NULL, "invariant"); |
|
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|
3748 assert(_task_queues->queue(_task_id) == _task_queue, "invariant"); |
|
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|
3749 |
|
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|
3750 assert(!_claimed, |
|
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|
3751 "only one thread should claim this task at any one time"); |
| 342 | 3752 |
| 3753 // OK, this doesn't safeguard again all possible scenarios, as it is | |
| 3754 // possible for two threads to set the _claimed flag at the same | |
| 3755 // time. But it is only for debugging purposes anyway and it will | |
| 3756 // catch most problems. | |
| 3757 _claimed = true; | |
| 3758 | |
| 3759 _start_time_ms = os::elapsedVTime() * 1000.0; | |
| 3760 statsOnly( _interval_start_time_ms = _start_time_ms ); | |
| 3761 | |
| 3762 double diff_prediction_ms = | |
| 3763 g1_policy->get_new_prediction(&_marking_step_diffs_ms); | |
| 3764 _time_target_ms = time_target_ms - diff_prediction_ms; | |
| 3765 | |
| 3766 // set up the variables that are used in the work-based scheme to | |
| 3767 // call the regular clock method | |
| 3768 _words_scanned = 0; | |
| 3769 _refs_reached = 0; | |
| 3770 recalculate_limits(); | |
| 3771 | |
| 3772 // clear all flags | |
| 3773 clear_has_aborted(); | |
| 3774 _has_aborted_timed_out = false; | |
| 3775 _draining_satb_buffers = false; | |
| 3776 | |
| 3777 ++_calls; | |
| 3778 | |
| 3779 if (_cm->verbose_low()) | |
| 3780 gclog_or_tty->print_cr("[%d] >>>>>>>>>> START, call = %d, " | |
| 3781 "target = %1.2lfms >>>>>>>>>>", | |
| 3782 _task_id, _calls, _time_target_ms); | |
| 3783 | |
| 3784 // Set up the bitmap and oop closures. Anything that uses them is | |
| 3785 // eventually called from this method, so it is OK to allocate these | |
| 3786 // statically. | |
| 3787 CMBitMapClosure bitmap_closure(this, _cm, _nextMarkBitMap); | |
| 3788 CMOopClosure oop_closure(_g1h, _cm, this); | |
| 3789 set_oop_closure(&oop_closure); | |
| 3790 | |
| 3791 if (_cm->has_overflown()) { | |
| 3792 // This can happen if the region stack or the mark stack overflows | |
| 3793 // during a GC pause and this task, after a yield point, | |
| 3794 // restarts. We have to abort as we need to get into the overflow | |
| 3795 // protocol which happens right at the end of this task. | |
| 3796 set_has_aborted(); | |
| 3797 } | |
| 3798 | |
| 3799 // First drain any available SATB buffers. After this, we will not | |
| 3800 // look at SATB buffers before the next invocation of this method. | |
| 3801 // If enough completed SATB buffers are queued up, the regular clock | |
| 3802 // will abort this task so that it restarts. | |
| 3803 drain_satb_buffers(); | |
| 3804 // ...then partially drain the local queue and the global stack | |
| 3805 drain_local_queue(true); | |
| 3806 drain_global_stack(true); | |
| 3807 | |
| 3808 // Then totally drain the region stack. We will not look at | |
| 3809 // it again before the next invocation of this method. Entries on | |
| 3810 // the region stack are only added during evacuation pauses, for | |
| 3811 // which we have to yield. When we do, we abort the task anyway so | |
| 3812 // it will look at the region stack again when it restarts. | |
| 3813 bitmap_closure.set_scanning_heap_region(false); | |
| 3814 drain_region_stack(&bitmap_closure); | |
| 3815 // ...then partially drain the local queue and the global stack | |
| 3816 drain_local_queue(true); | |
| 3817 drain_global_stack(true); | |
| 3818 | |
| 3819 do { | |
| 3820 if (!has_aborted() && _curr_region != NULL) { | |
| 3821 // This means that we're already holding on to a region. | |
|
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|
3822 assert(_finger != NULL, "if region is not NULL, then the finger " |
|
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|
3823 "should not be NULL either"); |
| 342 | 3824 |
| 3825 // We might have restarted this task after an evacuation pause | |
| 3826 // which might have evacuated the region we're holding on to | |
| 3827 // underneath our feet. Let's read its limit again to make sure | |
| 3828 // that we do not iterate over a region of the heap that | |
| 3829 // contains garbage (update_region_limit() will also move | |
| 3830 // _finger to the start of the region if it is found empty). | |
| 3831 update_region_limit(); | |
| 3832 // We will start from _finger not from the start of the region, | |
| 3833 // as we might be restarting this task after aborting half-way | |
| 3834 // through scanning this region. In this case, _finger points to | |
| 3835 // the address where we last found a marked object. If this is a | |
| 3836 // fresh region, _finger points to start(). | |
| 3837 MemRegion mr = MemRegion(_finger, _region_limit); | |
| 3838 | |
| 3839 if (_cm->verbose_low()) | |
| 3840 gclog_or_tty->print_cr("[%d] we're scanning part " | |
| 3841 "["PTR_FORMAT", "PTR_FORMAT") " | |
| 3842 "of region "PTR_FORMAT, | |
| 3843 _task_id, _finger, _region_limit, _curr_region); | |
| 3844 | |
| 3845 // Let's iterate over the bitmap of the part of the | |
| 3846 // region that is left. | |
| 3847 bitmap_closure.set_scanning_heap_region(true); | |
| 3848 if (mr.is_empty() || | |
| 3849 _nextMarkBitMap->iterate(&bitmap_closure, mr)) { | |
| 3850 // We successfully completed iterating over the region. Now, | |
| 3851 // let's give up the region. | |
| 3852 giveup_current_region(); | |
| 3853 regular_clock_call(); | |
| 3854 } else { | |
|
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|
3855 assert(has_aborted(), "currently the only way to do so"); |
| 342 | 3856 // The only way to abort the bitmap iteration is to return |
| 3857 // false from the do_bit() method. However, inside the | |
| 3858 // do_bit() method we move the _finger to point to the | |
| 3859 // object currently being looked at. So, if we bail out, we | |
| 3860 // have definitely set _finger to something non-null. | |
|
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|
3861 assert(_finger != NULL, "invariant"); |
| 342 | 3862 |
| 3863 // Region iteration was actually aborted. So now _finger | |
| 3864 // points to the address of the object we last scanned. If we | |
| 3865 // leave it there, when we restart this task, we will rescan | |
| 3866 // the object. It is easy to avoid this. We move the finger by | |
| 3867 // enough to point to the next possible object header (the | |
| 3868 // bitmap knows by how much we need to move it as it knows its | |
| 3869 // granularity). | |
|
1314
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
parents:
1284
diff
changeset
|
3870 assert(_finger < _region_limit, "invariant"); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
parents:
1284
diff
changeset
|
3871 HeapWord* new_finger = _nextMarkBitMap->nextWord(_finger); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
parents:
1284
diff
changeset
|
3872 // 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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1284
diff
changeset
|
3873 if (new_finger >= _region_limit) { |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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1284
diff
changeset
|
3874 giveup_current_region(); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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1284
diff
changeset
|
3875 } else { |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
parents:
1284
diff
changeset
|
3876 move_finger_to(new_finger); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
parents:
1284
diff
changeset
|
3877 } |
| 342 | 3878 } |
| 3879 } | |
| 3880 // At this point we have either completed iterating over the | |
| 3881 // region we were holding on to, or we have aborted. | |
| 3882 | |
| 3883 // We then partially drain the local queue and the global stack. | |
| 3884 // (Do we really need this?) | |
| 3885 drain_local_queue(true); | |
| 3886 drain_global_stack(true); | |
| 3887 | |
| 3888 // Read the note on the claim_region() method on why it might | |
| 3889 // return NULL with potentially more regions available for | |
| 3890 // claiming and why we have to check out_of_regions() to determine | |
| 3891 // whether we're done or not. | |
| 3892 while (!has_aborted() && _curr_region == NULL && !_cm->out_of_regions()) { | |
| 3893 // We are going to try to claim a new region. We should have | |
| 3894 // given up on the previous one. | |
|
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|
3895 // Separated the asserts so that we know which one fires. |
|
11d4857fe5e1
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|
3896 assert(_curr_region == NULL, "invariant"); |
|
11d4857fe5e1
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tonyp
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diff
changeset
|
3897 assert(_finger == NULL, "invariant"); |
|
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changeset
|
3898 assert(_region_limit == NULL, "invariant"); |
| 342 | 3899 if (_cm->verbose_low()) |
| 3900 gclog_or_tty->print_cr("[%d] trying to claim a new region", _task_id); | |
| 3901 HeapRegion* claimed_region = _cm->claim_region(_task_id); | |
| 3902 if (claimed_region != NULL) { | |
| 3903 // Yes, we managed to claim one | |
| 3904 statsOnly( ++_regions_claimed ); | |
| 3905 | |
| 3906 if (_cm->verbose_low()) | |
| 3907 gclog_or_tty->print_cr("[%d] we successfully claimed " | |
| 3908 "region "PTR_FORMAT, | |
| 3909 _task_id, claimed_region); | |
| 3910 | |
| 3911 setup_for_region(claimed_region); | |
|
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tonyp
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diff
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|
3912 assert(_curr_region == claimed_region, "invariant"); |
| 342 | 3913 } |
| 3914 // It is important to call the regular clock here. It might take | |
| 3915 // a while to claim a region if, for example, we hit a large | |
| 3916 // block of empty regions. So we need to call the regular clock | |
| 3917 // method once round the loop to make sure it's called | |
| 3918 // frequently enough. | |
| 3919 regular_clock_call(); | |
| 3920 } | |
| 3921 | |
| 3922 if (!has_aborted() && _curr_region == NULL) { | |
|
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|
3923 assert(_cm->out_of_regions(), |
|
11d4857fe5e1
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changeset
|
3924 "at this point we should be out of regions"); |
| 342 | 3925 } |
| 3926 } while ( _curr_region != NULL && !has_aborted()); | |
| 3927 | |
| 3928 if (!has_aborted()) { | |
| 3929 // 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, ...)
iveresov
parents:
342
diff
changeset
|
3930 // tasks might be pushing objects to it concurrently. We also cannot |
|
afc1ce1efe66
6710665: G1: guarantee(_cm->out_of_regions() && _cm->region_stack_empty() && _task_queue->size() == 0, ...)
iveresov
parents:
342
diff
changeset
|
3931 // check if the region stack is empty because if a thread is aborting |
|
afc1ce1efe66
6710665: G1: guarantee(_cm->out_of_regions() && _cm->region_stack_empty() && _task_queue->size() == 0, ...)
iveresov
parents:
342
diff
changeset
|
3932 // it can push a partially done region back. |
|
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|
3933 assert(_cm->out_of_regions(), |
|
11d4857fe5e1
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tonyp
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diff
changeset
|
3934 "at this point we should be out of regions"); |
| 342 | 3935 |
| 3936 if (_cm->verbose_low()) | |
| 3937 gclog_or_tty->print_cr("[%d] all regions claimed", _task_id); | |
| 3938 | |
| 3939 // Try to reduce the number of available SATB buffers so that | |
| 3940 // remark has less work to do. | |
| 3941 drain_satb_buffers(); | |
| 3942 } | |
| 3943 | |
| 3944 // Since we've done everything else, we can now totally drain the | |
| 3945 // local queue and global stack. | |
| 3946 drain_local_queue(false); | |
| 3947 drain_global_stack(false); | |
| 3948 | |
| 3949 // Attempt at work stealing from other task's queues. | |
| 3950 if (!has_aborted()) { | |
| 3951 // We have not aborted. This means that we have finished all that | |
| 3952 // we could. Let's try to do some stealing... | |
| 3953 | |
| 3954 // 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, ...)
iveresov
parents:
342
diff
changeset
|
3955 // tasks might be pushing objects to it concurrently. We also cannot |
|
afc1ce1efe66
6710665: G1: guarantee(_cm->out_of_regions() && _cm->region_stack_empty() && _task_queue->size() == 0, ...)
iveresov
parents:
342
diff
changeset
|
3956 // check if the region stack is empty because if a thread is aborting |
|
afc1ce1efe66
6710665: G1: guarantee(_cm->out_of_regions() && _cm->region_stack_empty() && _task_queue->size() == 0, ...)
iveresov
parents:
342
diff
changeset
|
3957 // it can push a partially done region back. |
|
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|
3958 assert(_cm->out_of_regions() && _task_queue->size() == 0, |
|
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|
3959 "only way to reach here"); |
| 342 | 3960 |
| 3961 if (_cm->verbose_low()) | |
| 3962 gclog_or_tty->print_cr("[%d] starting to steal", _task_id); | |
| 3963 | |
| 3964 while (!has_aborted()) { | |
| 3965 oop obj; | |
| 3966 statsOnly( ++_steal_attempts ); | |
| 3967 | |
| 3968 if (_cm->try_stealing(_task_id, &_hash_seed, obj)) { | |
| 3969 if (_cm->verbose_medium()) | |
| 3970 gclog_or_tty->print_cr("[%d] stolen "PTR_FORMAT" successfully", | |
| 3971 _task_id, (void*) obj); | |
| 3972 | |
| 3973 statsOnly( ++_steals ); | |
| 3974 | |
|
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|
3975 assert(_nextMarkBitMap->isMarked((HeapWord*) obj), |
|
11d4857fe5e1
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tonyp
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1022
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changeset
|
3976 "any stolen object should be marked"); |
| 342 | 3977 scan_object(obj); |
| 3978 | |
| 3979 // And since we're towards the end, let's totally drain the | |
| 3980 // local queue and global stack. | |
| 3981 drain_local_queue(false); | |
| 3982 drain_global_stack(false); | |
| 3983 } else { | |
| 3984 break; | |
| 3985 } | |
| 3986 } | |
| 3987 } | |
| 3988 | |
| 3989 // We still haven't aborted. Now, let's try to get into the | |
| 3990 // termination protocol. | |
| 3991 if (!has_aborted()) { | |
| 3992 // We cannot check whether the global stack is empty, since other | |
|
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3993 // tasks might be concurrently pushing objects on it. We also cannot |
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3994 // check if the region stack is empty because if a thread is aborting |
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3995 // it can push a partially done region back. |
|
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3996 // Separated the asserts so that we know which one fires. |
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3997 assert(_cm->out_of_regions(), "only way to reach here"); |
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3998 assert(_task_queue->size() == 0, "only way to reach here"); |
| 342 | 3999 |
| 4000 if (_cm->verbose_low()) | |
| 4001 gclog_or_tty->print_cr("[%d] starting termination protocol", _task_id); | |
| 4002 | |
| 4003 _termination_start_time_ms = os::elapsedVTime() * 1000.0; | |
| 4004 // The CMTask class also extends the TerminatorTerminator class, | |
| 4005 // hence its should_exit_termination() method will also decide | |
| 4006 // whether to exit the termination protocol or not. | |
| 4007 bool finished = _cm->terminator()->offer_termination(this); | |
| 4008 double termination_end_time_ms = os::elapsedVTime() * 1000.0; | |
| 4009 _termination_time_ms += | |
| 4010 termination_end_time_ms - _termination_start_time_ms; | |
| 4011 | |
| 4012 if (finished) { | |
| 4013 // We're all done. | |
| 4014 | |
| 4015 if (_task_id == 0) { | |
| 4016 // let's allow task 0 to do this | |
| 4017 if (concurrent()) { | |
|
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4018 assert(_cm->concurrent_marking_in_progress(), "invariant"); |
| 342 | 4019 // we need to set this to false before the next |
| 4020 // safepoint. This way we ensure that the marking phase | |
| 4021 // doesn't observe any more heap expansions. | |
| 4022 _cm->clear_concurrent_marking_in_progress(); | |
| 4023 } | |
| 4024 } | |
| 4025 | |
| 4026 // We can now guarantee that the global stack is empty, since | |
|
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4027 // all other tasks have finished. We separated the guarantees so |
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4028 // that, if a condition is false, we can immediately find out |
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4029 // which one. |
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4030 guarantee(_cm->out_of_regions(), "only way to reach here"); |
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4031 guarantee(_aborted_region.is_empty(), "only way to reach here"); |
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4032 guarantee(_cm->region_stack_empty(), "only way to reach here"); |
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4033 guarantee(_cm->mark_stack_empty(), "only way to reach here"); |
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4034 guarantee(_task_queue->size() == 0, "only way to reach here"); |
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4035 guarantee(!_cm->has_overflown(), "only way to reach here"); |
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4036 guarantee(!_cm->mark_stack_overflow(), "only way to reach here"); |
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4037 guarantee(!_cm->region_stack_overflow(), "only way to reach here"); |
| 342 | 4038 |
| 4039 if (_cm->verbose_low()) | |
| 4040 gclog_or_tty->print_cr("[%d] all tasks terminated", _task_id); | |
| 4041 } else { | |
| 4042 // Apparently there's more work to do. Let's abort this task. It | |
| 4043 // will restart it and we can hopefully find more things to do. | |
| 4044 | |
| 4045 if (_cm->verbose_low()) | |
| 4046 gclog_or_tty->print_cr("[%d] apparently there is more work to do", _task_id); | |
| 4047 | |
| 4048 set_has_aborted(); | |
| 4049 statsOnly( ++_aborted_termination ); | |
| 4050 } | |
| 4051 } | |
| 4052 | |
| 4053 // Mainly for debugging purposes to make sure that a pointer to the | |
| 4054 // closure which was statically allocated in this frame doesn't | |
| 4055 // escape it by accident. | |
| 4056 set_oop_closure(NULL); | |
| 4057 double end_time_ms = os::elapsedVTime() * 1000.0; | |
| 4058 double elapsed_time_ms = end_time_ms - _start_time_ms; | |
| 4059 // Update the step history. | |
| 4060 _step_times_ms.add(elapsed_time_ms); | |
| 4061 | |
| 4062 if (has_aborted()) { | |
| 4063 // The task was aborted for some reason. | |
| 4064 | |
| 4065 statsOnly( ++_aborted ); | |
| 4066 | |
| 4067 if (_has_aborted_timed_out) { | |
| 4068 double diff_ms = elapsed_time_ms - _time_target_ms; | |
| 4069 // Keep statistics of how well we did with respect to hitting | |
| 4070 // our target only if we actually timed out (if we aborted for | |
| 4071 // other reasons, then the results might get skewed). | |
| 4072 _marking_step_diffs_ms.add(diff_ms); | |
| 4073 } | |
| 4074 | |
| 4075 if (_cm->has_overflown()) { | |
| 4076 // This is the interesting one. We aborted because a global | |
| 4077 // overflow was raised. This means we have to restart the | |
| 4078 // marking phase and start iterating over regions. However, in | |
| 4079 // order to do this we have to make sure that all tasks stop | |
| 4080 // what they are doing and re-initialise in a safe manner. We | |
| 4081 // will achieve this with the use of two barrier sync points. | |
| 4082 | |
| 4083 if (_cm->verbose_low()) | |
| 4084 gclog_or_tty->print_cr("[%d] detected overflow", _task_id); | |
| 4085 | |
| 4086 _cm->enter_first_sync_barrier(_task_id); | |
| 4087 // When we exit this sync barrier we know that all tasks have | |
| 4088 // stopped doing marking work. So, it's now safe to | |
| 4089 // re-initialise our data structures. At the end of this method, | |
| 4090 // task 0 will clear the global data structures. | |
| 4091 | |
| 4092 statsOnly( ++_aborted_overflow ); | |
| 4093 | |
| 4094 // We clear the local state of this task... | |
| 4095 clear_region_fields(); | |
| 4096 | |
| 4097 // ...and enter the second barrier. | |
| 4098 _cm->enter_second_sync_barrier(_task_id); | |
| 4099 // At this point everything has bee re-initialised and we're | |
| 4100 // ready to restart. | |
| 4101 } | |
| 4102 | |
| 4103 if (_cm->verbose_low()) { | |
| 4104 gclog_or_tty->print_cr("[%d] <<<<<<<<<< ABORTING, target = %1.2lfms, " | |
| 4105 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4106 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4107 if (_cm->has_aborted()) | |
| 4108 gclog_or_tty->print_cr("[%d] ========== MARKING ABORTED ==========", | |
| 4109 _task_id); | |
| 4110 } | |
| 4111 } else { | |
| 4112 if (_cm->verbose_low()) | |
| 4113 gclog_or_tty->print_cr("[%d] <<<<<<<<<< FINISHED, target = %1.2lfms, " | |
| 4114 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4115 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4116 } | |
| 4117 | |
| 4118 _claimed = false; | |
| 4119 } | |
| 4120 | |
| 4121 CMTask::CMTask(int task_id, | |
| 4122 ConcurrentMark* cm, | |
| 4123 CMTaskQueue* task_queue, | |
| 4124 CMTaskQueueSet* task_queues) | |
| 4125 : _g1h(G1CollectedHeap::heap()), | |
| 4126 _task_id(task_id), _cm(cm), | |
| 4127 _claimed(false), | |
| 4128 _nextMarkBitMap(NULL), _hash_seed(17), | |
| 4129 _task_queue(task_queue), | |
| 4130 _task_queues(task_queues), | |
|
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4131 _oop_closure(NULL), |
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4132 _aborted_region(MemRegion()) { |
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4133 guarantee(task_queue != NULL, "invariant"); |
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4134 guarantee(task_queues != NULL, "invariant"); |
| 342 | 4135 |
| 4136 statsOnly( _clock_due_to_scanning = 0; | |
| 4137 _clock_due_to_marking = 0 ); | |
| 4138 | |
| 4139 _marking_step_diffs_ms.add(0.5); | |
| 4140 } |