Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp @ 4024:c08412904149
7099817: CMS: +FLSVerifyLists +FLSVerifyIndexTable asserts: odd slot non-empty, chunk not on free list
Summary: Suitably weaken asserts that were in each case a tad too strong; fix up some loose uses of parameters in code related to size-indexed free list table.
Reviewed-by: jmasa, brutisso, stefank
| author | ysr |
|---|---|
| date | Tue, 25 Oct 2011 20:15:41 -0700 |
| parents | 1e3493ac2d11 |
| children | 5a5ed80bea5b |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
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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. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "gc_implementation/concurrentMarkSweep/cmsLockVerifier.hpp" | |
| 27 #include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp" | |
| 28 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.inline.hpp" | |
| 29 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" | |
| 30 #include "gc_implementation/shared/liveRange.hpp" | |
| 31 #include "gc_implementation/shared/spaceDecorator.hpp" | |
| 32 #include "gc_interface/collectedHeap.hpp" | |
| 33 #include "memory/allocation.inline.hpp" | |
| 34 #include "memory/blockOffsetTable.inline.hpp" | |
| 35 #include "memory/resourceArea.hpp" | |
| 36 #include "memory/universe.inline.hpp" | |
| 37 #include "oops/oop.inline.hpp" | |
| 38 #include "runtime/globals.hpp" | |
| 39 #include "runtime/handles.inline.hpp" | |
| 40 #include "runtime/init.hpp" | |
| 41 #include "runtime/java.hpp" | |
| 42 #include "runtime/vmThread.hpp" | |
| 43 #include "utilities/copy.hpp" | |
| 0 | 44 |
| 45 ///////////////////////////////////////////////////////////////////////// | |
| 46 //// CompactibleFreeListSpace | |
| 47 ///////////////////////////////////////////////////////////////////////// | |
| 48 | |
| 49 // highest ranked free list lock rank | |
| 50 int CompactibleFreeListSpace::_lockRank = Mutex::leaf + 3; | |
| 51 | |
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52 // Defaults are 0 so things will break badly if incorrectly initialized. |
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53 int CompactibleFreeListSpace::IndexSetStart = 0; |
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54 int CompactibleFreeListSpace::IndexSetStride = 0; |
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55 |
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56 size_t MinChunkSize = 0; |
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57 |
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58 void CompactibleFreeListSpace::set_cms_values() { |
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59 // Set CMS global values |
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60 assert(MinChunkSize == 0, "already set"); |
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61 #define numQuanta(x,y) ((x+y-1)/y) |
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62 MinChunkSize = numQuanta(sizeof(FreeChunk), MinObjAlignmentInBytes) * MinObjAlignment; |
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63 |
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64 assert(IndexSetStart == 0 && IndexSetStride == 0, "already set"); |
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65 IndexSetStart = (int) MinChunkSize; |
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66 IndexSetStride = MinObjAlignment; |
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67 } |
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68 |
| 0 | 69 // Constructor |
| 70 CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs, | |
| 71 MemRegion mr, bool use_adaptive_freelists, | |
| 72 FreeBlockDictionary::DictionaryChoice dictionaryChoice) : | |
| 73 _dictionaryChoice(dictionaryChoice), | |
| 74 _adaptive_freelists(use_adaptive_freelists), | |
| 75 _bt(bs, mr), | |
| 76 // free list locks are in the range of values taken by _lockRank | |
| 77 // This range currently is [_leaf+2, _leaf+3] | |
| 78 // Note: this requires that CFLspace c'tors | |
| 79 // are called serially in the order in which the locks are | |
| 80 // are acquired in the program text. This is true today. | |
| 81 _freelistLock(_lockRank--, "CompactibleFreeListSpace._lock", true), | |
| 82 _parDictionaryAllocLock(Mutex::leaf - 1, // == rank(ExpandHeap_lock) - 1 | |
| 83 "CompactibleFreeListSpace._dict_par_lock", true), | |
| 84 _rescan_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord * | |
| 85 CMSRescanMultiple), | |
| 86 _marking_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord * | |
| 87 CMSConcMarkMultiple), | |
| 88 _collector(NULL) | |
| 89 { | |
| 90 _bt.set_space(this); | |
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91 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); |
| 0 | 92 // We have all of "mr", all of which we place in the dictionary |
| 93 // as one big chunk. We'll need to decide here which of several | |
| 94 // possible alternative dictionary implementations to use. For | |
| 95 // now the choice is easy, since we have only one working | |
| 96 // implementation, namely, the simple binary tree (splaying | |
| 97 // temporarily disabled). | |
| 98 switch (dictionaryChoice) { | |
| 99 case FreeBlockDictionary::dictionarySplayTree: | |
| 100 case FreeBlockDictionary::dictionarySkipList: | |
| 101 default: | |
| 102 warning("dictionaryChoice: selected option not understood; using" | |
| 103 " default BinaryTreeDictionary implementation instead."); | |
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104 case FreeBlockDictionary::dictionaryBinaryTree: |
| 0 | 105 _dictionary = new BinaryTreeDictionary(mr); |
| 106 break; | |
| 107 } | |
| 108 assert(_dictionary != NULL, "CMS dictionary initialization"); | |
| 109 // The indexed free lists are initially all empty and are lazily | |
| 110 // filled in on demand. Initialize the array elements to NULL. | |
| 111 initializeIndexedFreeListArray(); | |
| 112 | |
| 113 // Not using adaptive free lists assumes that allocation is first | |
| 114 // from the linAB's. Also a cms perm gen which can be compacted | |
| 115 // has to have the klass's klassKlass allocated at a lower | |
| 116 // address in the heap than the klass so that the klassKlass is | |
| 117 // moved to its new location before the klass is moved. | |
| 118 // Set the _refillSize for the linear allocation blocks | |
| 119 if (!use_adaptive_freelists) { | |
| 120 FreeChunk* fc = _dictionary->getChunk(mr.word_size()); | |
| 121 // The small linAB initially has all the space and will allocate | |
| 122 // a chunk of any size. | |
| 123 HeapWord* addr = (HeapWord*) fc; | |
| 124 _smallLinearAllocBlock.set(addr, fc->size() , | |
| 125 1024*SmallForLinearAlloc, fc->size()); | |
| 126 // Note that _unallocated_block is not updated here. | |
| 127 // Allocations from the linear allocation block should | |
| 128 // update it. | |
| 129 } else { | |
| 130 _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, | |
| 131 SmallForLinearAlloc); | |
| 132 } | |
| 133 // CMSIndexedFreeListReplenish should be at least 1 | |
| 134 CMSIndexedFreeListReplenish = MAX2((uintx)1, CMSIndexedFreeListReplenish); | |
| 135 _promoInfo.setSpace(this); | |
| 136 if (UseCMSBestFit) { | |
| 137 _fitStrategy = FreeBlockBestFitFirst; | |
| 138 } else { | |
| 139 _fitStrategy = FreeBlockStrategyNone; | |
| 140 } | |
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141 check_free_list_consistency(); |
| 0 | 142 |
| 143 // Initialize locks for parallel case. | |
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144 |
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145 if (CollectedHeap::use_parallel_gc_threads()) { |
| 0 | 146 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { |
| 147 _indexedFreeListParLocks[i] = new Mutex(Mutex::leaf - 1, // == ExpandHeap_lock - 1 | |
| 148 "a freelist par lock", | |
| 149 true); | |
| 150 if (_indexedFreeListParLocks[i] == NULL) | |
| 151 vm_exit_during_initialization("Could not allocate a par lock"); | |
| 152 DEBUG_ONLY( | |
| 153 _indexedFreeList[i].set_protecting_lock(_indexedFreeListParLocks[i]); | |
| 154 ) | |
| 155 } | |
| 156 _dictionary->set_par_lock(&_parDictionaryAllocLock); | |
| 157 } | |
| 158 } | |
| 159 | |
| 160 // Like CompactibleSpace forward() but always calls cross_threshold() to | |
| 161 // update the block offset table. Removed initialize_threshold call because | |
| 162 // CFLS does not use a block offset array for contiguous spaces. | |
| 163 HeapWord* CompactibleFreeListSpace::forward(oop q, size_t size, | |
| 164 CompactPoint* cp, HeapWord* compact_top) { | |
| 165 // q is alive | |
| 166 // First check if we should switch compaction space | |
| 167 assert(this == cp->space, "'this' should be current compaction space."); | |
| 168 size_t compaction_max_size = pointer_delta(end(), compact_top); | |
| 169 assert(adjustObjectSize(size) == cp->space->adjust_object_size_v(size), | |
| 170 "virtual adjustObjectSize_v() method is not correct"); | |
| 171 size_t adjusted_size = adjustObjectSize(size); | |
| 172 assert(compaction_max_size >= MinChunkSize || compaction_max_size == 0, | |
| 173 "no small fragments allowed"); | |
| 174 assert(minimum_free_block_size() == MinChunkSize, | |
| 175 "for de-virtualized reference below"); | |
| 176 // Can't leave a nonzero size, residual fragment smaller than MinChunkSize | |
| 177 if (adjusted_size + MinChunkSize > compaction_max_size && | |
| 178 adjusted_size != compaction_max_size) { | |
| 179 do { | |
| 180 // switch to next compaction space | |
| 181 cp->space->set_compaction_top(compact_top); | |
| 182 cp->space = cp->space->next_compaction_space(); | |
| 183 if (cp->space == NULL) { | |
| 184 cp->gen = GenCollectedHeap::heap()->prev_gen(cp->gen); | |
| 185 assert(cp->gen != NULL, "compaction must succeed"); | |
| 186 cp->space = cp->gen->first_compaction_space(); | |
| 187 assert(cp->space != NULL, "generation must have a first compaction space"); | |
| 188 } | |
| 189 compact_top = cp->space->bottom(); | |
| 190 cp->space->set_compaction_top(compact_top); | |
| 191 // The correct adjusted_size may not be the same as that for this method | |
| 192 // (i.e., cp->space may no longer be "this" so adjust the size again. | |
| 193 // Use the virtual method which is not used above to save the virtual | |
| 194 // dispatch. | |
| 195 adjusted_size = cp->space->adjust_object_size_v(size); | |
| 196 compaction_max_size = pointer_delta(cp->space->end(), compact_top); | |
| 197 assert(cp->space->minimum_free_block_size() == 0, "just checking"); | |
| 198 } while (adjusted_size > compaction_max_size); | |
| 199 } | |
| 200 | |
| 201 // store the forwarding pointer into the mark word | |
| 202 if ((HeapWord*)q != compact_top) { | |
| 203 q->forward_to(oop(compact_top)); | |
| 204 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); | |
| 205 } else { | |
| 206 // if the object isn't moving we can just set the mark to the default | |
| 207 // mark and handle it specially later on. | |
| 208 q->init_mark(); | |
| 209 assert(q->forwardee() == NULL, "should be forwarded to NULL"); | |
| 210 } | |
| 211 | |
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212 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::register_live_oop(q, adjusted_size)); |
| 0 | 213 compact_top += adjusted_size; |
| 214 | |
| 215 // we need to update the offset table so that the beginnings of objects can be | |
| 216 // found during scavenge. Note that we are updating the offset table based on | |
| 217 // where the object will be once the compaction phase finishes. | |
| 218 | |
| 219 // Always call cross_threshold(). A contiguous space can only call it when | |
| 220 // the compaction_top exceeds the current threshold but not for an | |
| 221 // non-contiguous space. | |
| 222 cp->threshold = | |
| 223 cp->space->cross_threshold(compact_top - adjusted_size, compact_top); | |
| 224 return compact_top; | |
| 225 } | |
| 226 | |
| 227 // A modified copy of OffsetTableContigSpace::cross_threshold() with _offsets -> _bt | |
| 228 // and use of single_block instead of alloc_block. The name here is not really | |
| 229 // appropriate - maybe a more general name could be invented for both the | |
| 230 // contiguous and noncontiguous spaces. | |
| 231 | |
| 232 HeapWord* CompactibleFreeListSpace::cross_threshold(HeapWord* start, HeapWord* the_end) { | |
| 233 _bt.single_block(start, the_end); | |
| 234 return end(); | |
| 235 } | |
| 236 | |
| 237 // Initialize them to NULL. | |
| 238 void CompactibleFreeListSpace::initializeIndexedFreeListArray() { | |
| 239 for (size_t i = 0; i < IndexSetSize; i++) { | |
| 240 // Note that on platforms where objects are double word aligned, | |
| 241 // the odd array elements are not used. It is convenient, however, | |
| 242 // to map directly from the object size to the array element. | |
| 243 _indexedFreeList[i].reset(IndexSetSize); | |
| 244 _indexedFreeList[i].set_size(i); | |
| 245 assert(_indexedFreeList[i].count() == 0, "reset check failed"); | |
| 246 assert(_indexedFreeList[i].head() == NULL, "reset check failed"); | |
| 247 assert(_indexedFreeList[i].tail() == NULL, "reset check failed"); | |
| 248 assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed"); | |
| 249 } | |
| 250 } | |
| 251 | |
| 252 void CompactibleFreeListSpace::resetIndexedFreeListArray() { | |
| 253 for (int i = 1; i < IndexSetSize; i++) { | |
| 254 assert(_indexedFreeList[i].size() == (size_t) i, | |
| 255 "Indexed free list sizes are incorrect"); | |
| 256 _indexedFreeList[i].reset(IndexSetSize); | |
| 257 assert(_indexedFreeList[i].count() == 0, "reset check failed"); | |
| 258 assert(_indexedFreeList[i].head() == NULL, "reset check failed"); | |
| 259 assert(_indexedFreeList[i].tail() == NULL, "reset check failed"); | |
| 260 assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed"); | |
| 261 } | |
| 262 } | |
| 263 | |
| 264 void CompactibleFreeListSpace::reset(MemRegion mr) { | |
| 265 resetIndexedFreeListArray(); | |
| 266 dictionary()->reset(); | |
| 267 if (BlockOffsetArrayUseUnallocatedBlock) { | |
| 268 assert(end() == mr.end(), "We are compacting to the bottom of CMS gen"); | |
| 269 // Everything's allocated until proven otherwise. | |
| 270 _bt.set_unallocated_block(end()); | |
| 271 } | |
| 272 if (!mr.is_empty()) { | |
| 273 assert(mr.word_size() >= MinChunkSize, "Chunk size is too small"); | |
| 274 _bt.single_block(mr.start(), mr.word_size()); | |
| 275 FreeChunk* fc = (FreeChunk*) mr.start(); | |
| 276 fc->setSize(mr.word_size()); | |
| 277 if (mr.word_size() >= IndexSetSize ) { | |
| 278 returnChunkToDictionary(fc); | |
| 279 } else { | |
| 280 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 281 _indexedFreeList[mr.word_size()].returnChunkAtHead(fc); | |
| 282 } | |
| 283 } | |
| 284 _promoInfo.reset(); | |
| 285 _smallLinearAllocBlock._ptr = NULL; | |
| 286 _smallLinearAllocBlock._word_size = 0; | |
| 287 } | |
| 288 | |
| 289 void CompactibleFreeListSpace::reset_after_compaction() { | |
| 290 // Reset the space to the new reality - one free chunk. | |
| 291 MemRegion mr(compaction_top(), end()); | |
| 292 reset(mr); | |
| 293 // Now refill the linear allocation block(s) if possible. | |
| 294 if (_adaptive_freelists) { | |
| 295 refillLinearAllocBlocksIfNeeded(); | |
| 296 } else { | |
| 297 // Place as much of mr in the linAB as we can get, | |
| 298 // provided it was big enough to go into the dictionary. | |
| 299 FreeChunk* fc = dictionary()->findLargestDict(); | |
| 300 if (fc != NULL) { | |
| 301 assert(fc->size() == mr.word_size(), | |
| 302 "Why was the chunk broken up?"); | |
| 303 removeChunkFromDictionary(fc); | |
| 304 HeapWord* addr = (HeapWord*) fc; | |
| 305 _smallLinearAllocBlock.set(addr, fc->size() , | |
| 306 1024*SmallForLinearAlloc, fc->size()); | |
| 307 // Note that _unallocated_block is not updated here. | |
| 308 } | |
| 309 } | |
| 310 } | |
| 311 | |
| 312 // Walks the entire dictionary, returning a coterminal | |
| 313 // chunk, if it exists. Use with caution since it involves | |
| 314 // a potentially complete walk of a potentially large tree. | |
| 315 FreeChunk* CompactibleFreeListSpace::find_chunk_at_end() { | |
| 316 | |
| 317 assert_lock_strong(&_freelistLock); | |
| 318 | |
| 319 return dictionary()->find_chunk_ends_at(end()); | |
| 320 } | |
| 321 | |
| 322 | |
| 323 #ifndef PRODUCT | |
| 324 void CompactibleFreeListSpace::initializeIndexedFreeListArrayReturnedBytes() { | |
| 325 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 326 _indexedFreeList[i].allocation_stats()->set_returnedBytes(0); | |
| 327 } | |
| 328 } | |
| 329 | |
| 330 size_t CompactibleFreeListSpace::sumIndexedFreeListArrayReturnedBytes() { | |
| 331 size_t sum = 0; | |
| 332 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 333 sum += _indexedFreeList[i].allocation_stats()->returnedBytes(); | |
| 334 } | |
| 335 return sum; | |
| 336 } | |
| 337 | |
| 338 size_t CompactibleFreeListSpace::totalCountInIndexedFreeLists() const { | |
| 339 size_t count = 0; | |
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340 for (int i = (int)MinChunkSize; i < IndexSetSize; i++) { |
| 0 | 341 debug_only( |
| 342 ssize_t total_list_count = 0; | |
| 343 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 344 fc = fc->next()) { | |
| 345 total_list_count++; | |
| 346 } | |
| 347 assert(total_list_count == _indexedFreeList[i].count(), | |
| 348 "Count in list is incorrect"); | |
| 349 ) | |
| 350 count += _indexedFreeList[i].count(); | |
| 351 } | |
| 352 return count; | |
| 353 } | |
| 354 | |
| 355 size_t CompactibleFreeListSpace::totalCount() { | |
| 356 size_t num = totalCountInIndexedFreeLists(); | |
| 357 num += dictionary()->totalCount(); | |
| 358 if (_smallLinearAllocBlock._word_size != 0) { | |
| 359 num++; | |
| 360 } | |
| 361 return num; | |
| 362 } | |
| 363 #endif | |
| 364 | |
| 365 bool CompactibleFreeListSpace::is_free_block(const HeapWord* p) const { | |
| 366 FreeChunk* fc = (FreeChunk*) p; | |
| 367 return fc->isFree(); | |
| 368 } | |
| 369 | |
| 370 size_t CompactibleFreeListSpace::used() const { | |
| 371 return capacity() - free(); | |
| 372 } | |
| 373 | |
| 374 size_t CompactibleFreeListSpace::free() const { | |
| 375 // "MT-safe, but not MT-precise"(TM), if you will: i.e. | |
| 376 // if you do this while the structures are in flux you | |
| 377 // may get an approximate answer only; for instance | |
| 378 // because there is concurrent allocation either | |
| 379 // directly by mutators or for promotion during a GC. | |
| 380 // It's "MT-safe", however, in the sense that you are guaranteed | |
| 381 // not to crash and burn, for instance, because of walking | |
| 382 // pointers that could disappear as you were walking them. | |
| 383 // The approximation is because the various components | |
| 384 // that are read below are not read atomically (and | |
| 385 // further the computation of totalSizeInIndexedFreeLists() | |
| 386 // is itself a non-atomic computation. The normal use of | |
| 387 // this is during a resize operation at the end of GC | |
| 388 // and at that time you are guaranteed to get the | |
| 389 // correct actual value. However, for instance, this is | |
| 390 // also read completely asynchronously by the "perf-sampler" | |
| 391 // that supports jvmstat, and you are apt to see the values | |
| 392 // flicker in such cases. | |
| 393 assert(_dictionary != NULL, "No _dictionary?"); | |
| 394 return (_dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())) + | |
| 395 totalSizeInIndexedFreeLists() + | |
| 396 _smallLinearAllocBlock._word_size) * HeapWordSize; | |
| 397 } | |
| 398 | |
| 399 size_t CompactibleFreeListSpace::max_alloc_in_words() const { | |
| 400 assert(_dictionary != NULL, "No _dictionary?"); | |
| 401 assert_locked(); | |
| 402 size_t res = _dictionary->maxChunkSize(); | |
| 403 res = MAX2(res, MIN2(_smallLinearAllocBlock._word_size, | |
| 404 (size_t) SmallForLinearAlloc - 1)); | |
| 405 // XXX the following could potentially be pretty slow; | |
| 406 // should one, pesimally for the rare cases when res | |
| 407 // caclulated above is less than IndexSetSize, | |
| 408 // just return res calculated above? My reasoning was that | |
| 409 // those cases will be so rare that the extra time spent doesn't | |
| 410 // really matter.... | |
| 411 // Note: do not change the loop test i >= res + IndexSetStride | |
| 412 // to i > res below, because i is unsigned and res may be zero. | |
| 413 for (size_t i = IndexSetSize - 1; i >= res + IndexSetStride; | |
| 414 i -= IndexSetStride) { | |
| 415 if (_indexedFreeList[i].head() != NULL) { | |
| 416 assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList"); | |
| 417 return i; | |
| 418 } | |
| 419 } | |
| 420 return res; | |
| 421 } | |
| 422 | |
|
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423 void LinearAllocBlock::print_on(outputStream* st) const { |
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424 st->print_cr(" LinearAllocBlock: ptr = " PTR_FORMAT ", word_size = " SIZE_FORMAT |
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425 ", refillsize = " SIZE_FORMAT ", allocation_size_limit = " SIZE_FORMAT, |
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426 _ptr, _word_size, _refillSize, _allocation_size_limit); |
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427 } |
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428 |
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429 void CompactibleFreeListSpace::print_on(outputStream* st) const { |
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430 st->print_cr("COMPACTIBLE FREELIST SPACE"); |
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431 st->print_cr(" Space:"); |
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432 Space::print_on(st); |
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433 |
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434 st->print_cr("promoInfo:"); |
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435 _promoInfo.print_on(st); |
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436 |
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437 st->print_cr("_smallLinearAllocBlock"); |
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438 _smallLinearAllocBlock.print_on(st); |
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439 |
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440 // dump_memory_block(_smallLinearAllocBlock->_ptr, 128); |
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441 |
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442 st->print_cr(" _fitStrategy = %s, _adaptive_freelists = %s", |
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443 _fitStrategy?"true":"false", _adaptive_freelists?"true":"false"); |
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444 } |
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445 |
|
1145
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446 void CompactibleFreeListSpace::print_indexed_free_lists(outputStream* st) |
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447 const { |
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448 reportIndexedFreeListStatistics(); |
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449 gclog_or_tty->print_cr("Layout of Indexed Freelists"); |
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450 gclog_or_tty->print_cr("---------------------------"); |
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451 FreeList::print_labels_on(st, "size"); |
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452 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { |
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453 _indexedFreeList[i].print_on(gclog_or_tty); |
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454 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; |
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455 fc = fc->next()) { |
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456 gclog_or_tty->print_cr("\t[" PTR_FORMAT "," PTR_FORMAT ") %s", |
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457 fc, (HeapWord*)fc + i, |
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458 fc->cantCoalesce() ? "\t CC" : ""); |
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459 } |
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460 } |
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461 } |
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462 |
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463 void CompactibleFreeListSpace::print_promo_info_blocks(outputStream* st) |
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464 const { |
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465 _promoInfo.print_on(st); |
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466 } |
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467 |
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468 void CompactibleFreeListSpace::print_dictionary_free_lists(outputStream* st) |
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469 const { |
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470 _dictionary->reportStatistics(); |
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471 st->print_cr("Layout of Freelists in Tree"); |
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472 st->print_cr("---------------------------"); |
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473 _dictionary->print_free_lists(st); |
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474 } |
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475 |
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476 class BlkPrintingClosure: public BlkClosure { |
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477 const CMSCollector* _collector; |
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478 const CompactibleFreeListSpace* _sp; |
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479 const CMSBitMap* _live_bit_map; |
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480 const bool _post_remark; |
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481 outputStream* _st; |
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482 public: |
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483 BlkPrintingClosure(const CMSCollector* collector, |
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484 const CompactibleFreeListSpace* sp, |
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485 const CMSBitMap* live_bit_map, |
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486 outputStream* st): |
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487 _collector(collector), |
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488 _sp(sp), |
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489 _live_bit_map(live_bit_map), |
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490 _post_remark(collector->abstract_state() > CMSCollector::FinalMarking), |
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491 _st(st) { } |
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492 size_t do_blk(HeapWord* addr); |
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493 }; |
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494 |
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495 size_t BlkPrintingClosure::do_blk(HeapWord* addr) { |
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496 size_t sz = _sp->block_size_no_stall(addr, _collector); |
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497 assert(sz != 0, "Should always be able to compute a size"); |
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498 if (_sp->block_is_obj(addr)) { |
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499 const bool dead = _post_remark && !_live_bit_map->isMarked(addr); |
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500 _st->print_cr(PTR_FORMAT ": %s object of size " SIZE_FORMAT "%s", |
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501 addr, |
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502 dead ? "dead" : "live", |
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503 sz, |
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504 (!dead && CMSPrintObjectsInDump) ? ":" : "."); |
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505 if (CMSPrintObjectsInDump && !dead) { |
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506 oop(addr)->print_on(_st); |
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507 _st->print_cr("--------------------------------------"); |
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508 } |
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509 } else { // free block |
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510 _st->print_cr(PTR_FORMAT ": free block of size " SIZE_FORMAT "%s", |
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511 addr, sz, CMSPrintChunksInDump ? ":" : "."); |
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512 if (CMSPrintChunksInDump) { |
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513 ((FreeChunk*)addr)->print_on(_st); |
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514 _st->print_cr("--------------------------------------"); |
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515 } |
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516 } |
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517 return sz; |
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518 } |
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519 |
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520 void CompactibleFreeListSpace::dump_at_safepoint_with_locks(CMSCollector* c, |
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521 outputStream* st) { |
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522 st->print_cr("\n========================="); |
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523 st->print_cr("Block layout in CMS Heap:"); |
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524 st->print_cr("========================="); |
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525 BlkPrintingClosure bpcl(c, this, c->markBitMap(), st); |
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526 blk_iterate(&bpcl); |
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527 |
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528 st->print_cr("\n======================================="); |
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529 st->print_cr("Order & Layout of Promotion Info Blocks"); |
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530 st->print_cr("======================================="); |
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531 print_promo_info_blocks(st); |
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532 |
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533 st->print_cr("\n==========================="); |
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534 st->print_cr("Order of Indexed Free Lists"); |
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535 st->print_cr("========================="); |
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536 print_indexed_free_lists(st); |
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537 |
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538 st->print_cr("\n================================="); |
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539 st->print_cr("Order of Free Lists in Dictionary"); |
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540 st->print_cr("================================="); |
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541 print_dictionary_free_lists(st); |
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542 } |
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543 |
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544 |
| 0 | 545 void CompactibleFreeListSpace::reportFreeListStatistics() const { |
| 546 assert_lock_strong(&_freelistLock); | |
| 547 assert(PrintFLSStatistics != 0, "Reporting error"); | |
| 548 _dictionary->reportStatistics(); | |
| 549 if (PrintFLSStatistics > 1) { | |
| 550 reportIndexedFreeListStatistics(); | |
| 551 size_t totalSize = totalSizeInIndexedFreeLists() + | |
| 552 _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())); | |
| 553 gclog_or_tty->print(" free=%ld frag=%1.4f\n", totalSize, flsFrag()); | |
| 554 } | |
| 555 } | |
| 556 | |
| 557 void CompactibleFreeListSpace::reportIndexedFreeListStatistics() const { | |
| 558 assert_lock_strong(&_freelistLock); | |
| 559 gclog_or_tty->print("Statistics for IndexedFreeLists:\n" | |
| 560 "--------------------------------\n"); | |
| 561 size_t totalSize = totalSizeInIndexedFreeLists(); | |
| 562 size_t freeBlocks = numFreeBlocksInIndexedFreeLists(); | |
| 563 gclog_or_tty->print("Total Free Space: %d\n", totalSize); | |
| 564 gclog_or_tty->print("Max Chunk Size: %d\n", maxChunkSizeInIndexedFreeLists()); | |
| 565 gclog_or_tty->print("Number of Blocks: %d\n", freeBlocks); | |
| 566 if (freeBlocks != 0) { | |
| 567 gclog_or_tty->print("Av. Block Size: %d\n", totalSize/freeBlocks); | |
| 568 } | |
| 569 } | |
| 570 | |
| 571 size_t CompactibleFreeListSpace::numFreeBlocksInIndexedFreeLists() const { | |
| 572 size_t res = 0; | |
| 573 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 574 debug_only( | |
| 575 ssize_t recount = 0; | |
| 576 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 577 fc = fc->next()) { | |
| 578 recount += 1; | |
| 579 } | |
| 580 assert(recount == _indexedFreeList[i].count(), | |
| 581 "Incorrect count in list"); | |
| 582 ) | |
| 583 res += _indexedFreeList[i].count(); | |
| 584 } | |
| 585 return res; | |
| 586 } | |
| 587 | |
| 588 size_t CompactibleFreeListSpace::maxChunkSizeInIndexedFreeLists() const { | |
| 589 for (size_t i = IndexSetSize - 1; i != 0; i -= IndexSetStride) { | |
| 590 if (_indexedFreeList[i].head() != NULL) { | |
| 591 assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList"); | |
| 592 return (size_t)i; | |
| 593 } | |
| 594 } | |
| 595 return 0; | |
| 596 } | |
| 597 | |
| 598 void CompactibleFreeListSpace::set_end(HeapWord* value) { | |
| 599 HeapWord* prevEnd = end(); | |
| 600 assert(prevEnd != value, "unnecessary set_end call"); | |
|
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601 assert(prevEnd == NULL || !BlockOffsetArrayUseUnallocatedBlock || value >= unallocated_block(), |
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602 "New end is below unallocated block"); |
| 0 | 603 _end = value; |
| 604 if (prevEnd != NULL) { | |
| 605 // Resize the underlying block offset table. | |
| 606 _bt.resize(pointer_delta(value, bottom())); | |
|
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607 if (value <= prevEnd) { |
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608 assert(!BlockOffsetArrayUseUnallocatedBlock || value >= unallocated_block(), |
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609 "New end is below unallocated block"); |
|
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610 } else { |
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611 // Now, take this new chunk and add it to the free blocks. |
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612 // Note that the BOT has not yet been updated for this block. |
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613 size_t newFcSize = pointer_delta(value, prevEnd); |
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614 // XXX This is REALLY UGLY and should be fixed up. XXX |
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615 if (!_adaptive_freelists && _smallLinearAllocBlock._ptr == NULL) { |
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616 // Mark the boundary of the new block in BOT |
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617 _bt.mark_block(prevEnd, value); |
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618 // put it all in the linAB |
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619 if (ParallelGCThreads == 0) { |
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620 _smallLinearAllocBlock._ptr = prevEnd; |
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621 _smallLinearAllocBlock._word_size = newFcSize; |
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622 repairLinearAllocBlock(&_smallLinearAllocBlock); |
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623 } else { // ParallelGCThreads > 0 |
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624 MutexLockerEx x(parDictionaryAllocLock(), |
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625 Mutex::_no_safepoint_check_flag); |
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626 _smallLinearAllocBlock._ptr = prevEnd; |
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627 _smallLinearAllocBlock._word_size = newFcSize; |
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628 repairLinearAllocBlock(&_smallLinearAllocBlock); |
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629 } |
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630 // Births of chunks put into a LinAB are not recorded. Births |
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631 // of chunks as they are allocated out of a LinAB are. |
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632 } else { |
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633 // Add the block to the free lists, if possible coalescing it |
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634 // with the last free block, and update the BOT and census data. |
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635 addChunkToFreeListsAtEndRecordingStats(prevEnd, newFcSize); |
| 0 | 636 } |
| 637 } | |
| 638 } | |
| 639 } | |
| 640 | |
| 641 class FreeListSpace_DCTOC : public Filtering_DCTOC { | |
| 642 CompactibleFreeListSpace* _cfls; | |
| 643 CMSCollector* _collector; | |
| 644 protected: | |
| 645 // Override. | |
| 646 #define walk_mem_region_with_cl_DECL(ClosureType) \ | |
| 647 virtual void walk_mem_region_with_cl(MemRegion mr, \ | |
| 648 HeapWord* bottom, HeapWord* top, \ | |
| 649 ClosureType* cl); \ | |
| 650 void walk_mem_region_with_cl_par(MemRegion mr, \ | |
| 651 HeapWord* bottom, HeapWord* top, \ | |
| 652 ClosureType* cl); \ | |
| 653 void walk_mem_region_with_cl_nopar(MemRegion mr, \ | |
| 654 HeapWord* bottom, HeapWord* top, \ | |
| 655 ClosureType* cl) | |
| 656 walk_mem_region_with_cl_DECL(OopClosure); | |
| 657 walk_mem_region_with_cl_DECL(FilteringClosure); | |
| 658 | |
| 659 public: | |
| 660 FreeListSpace_DCTOC(CompactibleFreeListSpace* sp, | |
| 661 CMSCollector* collector, | |
| 662 OopClosure* cl, | |
| 663 CardTableModRefBS::PrecisionStyle precision, | |
| 664 HeapWord* boundary) : | |
| 665 Filtering_DCTOC(sp, cl, precision, boundary), | |
| 666 _cfls(sp), _collector(collector) {} | |
| 667 }; | |
| 668 | |
| 669 // We de-virtualize the block-related calls below, since we know that our | |
| 670 // space is a CompactibleFreeListSpace. | |
| 671 #define FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ | |
| 672 void FreeListSpace_DCTOC::walk_mem_region_with_cl(MemRegion mr, \ | |
| 673 HeapWord* bottom, \ | |
| 674 HeapWord* top, \ | |
| 675 ClosureType* cl) { \ | |
| 676 if (SharedHeap::heap()->n_par_threads() > 0) { \ | |
| 677 walk_mem_region_with_cl_par(mr, bottom, top, cl); \ | |
| 678 } else { \ | |
| 679 walk_mem_region_with_cl_nopar(mr, bottom, top, cl); \ | |
| 680 } \ | |
| 681 } \ | |
| 682 void FreeListSpace_DCTOC::walk_mem_region_with_cl_par(MemRegion mr, \ | |
| 683 HeapWord* bottom, \ | |
| 684 HeapWord* top, \ | |
| 685 ClosureType* cl) { \ | |
| 686 /* Skip parts that are before "mr", in case "block_start" sent us \ | |
| 687 back too far. */ \ | |
| 688 HeapWord* mr_start = mr.start(); \ | |
| 689 size_t bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 690 HeapWord* next = bottom + bot_size; \ | |
| 691 while (next < mr_start) { \ | |
| 692 bottom = next; \ | |
| 693 bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 694 next = bottom + bot_size; \ | |
| 695 } \ | |
| 696 \ | |
| 697 while (bottom < top) { \ | |
| 698 if (_cfls->CompactibleFreeListSpace::block_is_obj(bottom) && \ | |
| 699 !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks( \ | |
| 700 oop(bottom)) && \ | |
| 701 !_collector->CMSCollector::is_dead_obj(oop(bottom))) { \ | |
| 702 size_t word_sz = oop(bottom)->oop_iterate(cl, mr); \ | |
| 703 bottom += _cfls->adjustObjectSize(word_sz); \ | |
| 704 } else { \ | |
| 705 bottom += _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 706 } \ | |
| 707 } \ | |
| 708 } \ | |
| 709 void FreeListSpace_DCTOC::walk_mem_region_with_cl_nopar(MemRegion mr, \ | |
| 710 HeapWord* bottom, \ | |
| 711 HeapWord* top, \ | |
| 712 ClosureType* cl) { \ | |
| 713 /* Skip parts that are before "mr", in case "block_start" sent us \ | |
| 714 back too far. */ \ | |
| 715 HeapWord* mr_start = mr.start(); \ | |
| 716 size_t bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 717 HeapWord* next = bottom + bot_size; \ | |
| 718 while (next < mr_start) { \ | |
| 719 bottom = next; \ | |
| 720 bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 721 next = bottom + bot_size; \ | |
| 722 } \ | |
| 723 \ | |
| 724 while (bottom < top) { \ | |
| 725 if (_cfls->CompactibleFreeListSpace::block_is_obj_nopar(bottom) && \ | |
| 726 !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks( \ | |
| 727 oop(bottom)) && \ | |
| 728 !_collector->CMSCollector::is_dead_obj(oop(bottom))) { \ | |
| 729 size_t word_sz = oop(bottom)->oop_iterate(cl, mr); \ | |
| 730 bottom += _cfls->adjustObjectSize(word_sz); \ | |
| 731 } else { \ | |
| 732 bottom += _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 733 } \ | |
| 734 } \ | |
| 735 } | |
| 736 | |
| 737 // (There are only two of these, rather than N, because the split is due | |
| 738 // only to the introduction of the FilteringClosure, a local part of the | |
| 739 // impl of this abstraction.) | |
| 740 FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(OopClosure) | |
| 741 FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) | |
| 742 | |
| 743 DirtyCardToOopClosure* | |
| 744 CompactibleFreeListSpace::new_dcto_cl(OopClosure* cl, | |
| 745 CardTableModRefBS::PrecisionStyle precision, | |
| 746 HeapWord* boundary) { | |
| 747 return new FreeListSpace_DCTOC(this, _collector, cl, precision, boundary); | |
| 748 } | |
| 749 | |
| 750 | |
| 751 // Note on locking for the space iteration functions: | |
| 752 // since the collector's iteration activities are concurrent with | |
| 753 // allocation activities by mutators, absent a suitable mutual exclusion | |
| 754 // mechanism the iterators may go awry. For instace a block being iterated | |
| 755 // may suddenly be allocated or divided up and part of it allocated and | |
| 756 // so on. | |
| 757 | |
| 758 // Apply the given closure to each block in the space. | |
| 759 void CompactibleFreeListSpace::blk_iterate_careful(BlkClosureCareful* cl) { | |
| 760 assert_lock_strong(freelistLock()); | |
| 761 HeapWord *cur, *limit; | |
| 762 for (cur = bottom(), limit = end(); cur < limit; | |
| 763 cur += cl->do_blk_careful(cur)); | |
| 764 } | |
| 765 | |
| 766 // Apply the given closure to each block in the space. | |
| 767 void CompactibleFreeListSpace::blk_iterate(BlkClosure* cl) { | |
| 768 assert_lock_strong(freelistLock()); | |
| 769 HeapWord *cur, *limit; | |
| 770 for (cur = bottom(), limit = end(); cur < limit; | |
| 771 cur += cl->do_blk(cur)); | |
| 772 } | |
| 773 | |
| 774 // Apply the given closure to each oop in the space. | |
| 775 void CompactibleFreeListSpace::oop_iterate(OopClosure* cl) { | |
| 776 assert_lock_strong(freelistLock()); | |
| 777 HeapWord *cur, *limit; | |
| 778 size_t curSize; | |
| 779 for (cur = bottom(), limit = end(); cur < limit; | |
| 780 cur += curSize) { | |
| 781 curSize = block_size(cur); | |
| 782 if (block_is_obj(cur)) { | |
| 783 oop(cur)->oop_iterate(cl); | |
| 784 } | |
| 785 } | |
| 786 } | |
| 787 | |
| 788 // Apply the given closure to each oop in the space \intersect memory region. | |
| 789 void CompactibleFreeListSpace::oop_iterate(MemRegion mr, OopClosure* cl) { | |
| 790 assert_lock_strong(freelistLock()); | |
| 791 if (is_empty()) { | |
| 792 return; | |
| 793 } | |
| 794 MemRegion cur = MemRegion(bottom(), end()); | |
| 795 mr = mr.intersection(cur); | |
| 796 if (mr.is_empty()) { | |
| 797 return; | |
| 798 } | |
| 799 if (mr.equals(cur)) { | |
| 800 oop_iterate(cl); | |
| 801 return; | |
| 802 } | |
| 803 assert(mr.end() <= end(), "just took an intersection above"); | |
| 804 HeapWord* obj_addr = block_start(mr.start()); | |
| 805 HeapWord* t = mr.end(); | |
| 806 | |
| 807 SpaceMemRegionOopsIterClosure smr_blk(cl, mr); | |
| 808 if (block_is_obj(obj_addr)) { | |
| 809 // Handle first object specially. | |
| 810 oop obj = oop(obj_addr); | |
| 811 obj_addr += adjustObjectSize(obj->oop_iterate(&smr_blk)); | |
| 812 } else { | |
| 813 FreeChunk* fc = (FreeChunk*)obj_addr; | |
| 814 obj_addr += fc->size(); | |
| 815 } | |
| 816 while (obj_addr < t) { | |
| 817 HeapWord* obj = obj_addr; | |
| 818 obj_addr += block_size(obj_addr); | |
| 819 // If "obj_addr" is not greater than top, then the | |
| 820 // entire object "obj" is within the region. | |
| 821 if (obj_addr <= t) { | |
| 822 if (block_is_obj(obj)) { | |
| 823 oop(obj)->oop_iterate(cl); | |
| 824 } | |
| 825 } else { | |
| 826 // "obj" extends beyond end of region | |
| 827 if (block_is_obj(obj)) { | |
| 828 oop(obj)->oop_iterate(&smr_blk); | |
| 829 } | |
| 830 break; | |
| 831 } | |
| 832 } | |
| 833 } | |
| 834 | |
| 835 // NOTE: In the following methods, in order to safely be able to | |
| 836 // apply the closure to an object, we need to be sure that the | |
| 837 // object has been initialized. We are guaranteed that an object | |
| 838 // is initialized if we are holding the Heap_lock with the | |
| 839 // world stopped. | |
| 840 void CompactibleFreeListSpace::verify_objects_initialized() const { | |
| 841 if (is_init_completed()) { | |
| 842 assert_locked_or_safepoint(Heap_lock); | |
| 843 if (Universe::is_fully_initialized()) { | |
| 844 guarantee(SafepointSynchronize::is_at_safepoint(), | |
| 845 "Required for objects to be initialized"); | |
| 846 } | |
| 847 } // else make a concession at vm start-up | |
| 848 } | |
| 849 | |
| 850 // Apply the given closure to each object in the space | |
| 851 void CompactibleFreeListSpace::object_iterate(ObjectClosure* blk) { | |
| 852 assert_lock_strong(freelistLock()); | |
| 853 NOT_PRODUCT(verify_objects_initialized()); | |
| 854 HeapWord *cur, *limit; | |
| 855 size_t curSize; | |
| 856 for (cur = bottom(), limit = end(); cur < limit; | |
| 857 cur += curSize) { | |
| 858 curSize = block_size(cur); | |
| 859 if (block_is_obj(cur)) { | |
| 860 blk->do_object(oop(cur)); | |
| 861 } | |
| 862 } | |
| 863 } | |
| 864 | |
|
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865 // Apply the given closure to each live object in the space |
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866 // The usage of CompactibleFreeListSpace |
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867 // by the ConcurrentMarkSweepGeneration for concurrent GC's allows |
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868 // objects in the space with references to objects that are no longer |
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869 // valid. For example, an object may reference another object |
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870 // that has already been sweep up (collected). This method uses |
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871 // obj_is_alive() to determine whether it is safe to apply the closure to |
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872 // an object. See obj_is_alive() for details on how liveness of an |
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873 // object is decided. |
|
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874 |
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875 void CompactibleFreeListSpace::safe_object_iterate(ObjectClosure* blk) { |
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876 assert_lock_strong(freelistLock()); |
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877 NOT_PRODUCT(verify_objects_initialized()); |
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878 HeapWord *cur, *limit; |
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879 size_t curSize; |
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880 for (cur = bottom(), limit = end(); cur < limit; |
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881 cur += curSize) { |
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882 curSize = block_size(cur); |
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883 if (block_is_obj(cur) && obj_is_alive(cur)) { |
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884 blk->do_object(oop(cur)); |
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885 } |
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886 } |
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887 } |
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888 |
| 0 | 889 void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr, |
| 890 UpwardsObjectClosure* cl) { | |
|
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891 assert_locked(freelistLock()); |
| 0 | 892 NOT_PRODUCT(verify_objects_initialized()); |
| 893 Space::object_iterate_mem(mr, cl); | |
| 894 } | |
| 895 | |
| 896 // Callers of this iterator beware: The closure application should | |
| 897 // be robust in the face of uninitialized objects and should (always) | |
| 898 // return a correct size so that the next addr + size below gives us a | |
| 899 // valid block boundary. [See for instance, | |
| 900 // ScanMarkedObjectsAgainCarefullyClosure::do_object_careful() | |
| 901 // in ConcurrentMarkSweepGeneration.cpp.] | |
| 902 HeapWord* | |
| 903 CompactibleFreeListSpace::object_iterate_careful(ObjectClosureCareful* cl) { | |
| 904 assert_lock_strong(freelistLock()); | |
| 905 HeapWord *addr, *last; | |
| 906 size_t size; | |
| 907 for (addr = bottom(), last = end(); | |
| 908 addr < last; addr += size) { | |
| 909 FreeChunk* fc = (FreeChunk*)addr; | |
| 910 if (fc->isFree()) { | |
| 911 // Since we hold the free list lock, which protects direct | |
| 912 // allocation in this generation by mutators, a free object | |
| 913 // will remain free throughout this iteration code. | |
| 914 size = fc->size(); | |
| 915 } else { | |
| 916 // Note that the object need not necessarily be initialized, | |
| 917 // because (for instance) the free list lock does NOT protect | |
| 918 // object initialization. The closure application below must | |
| 919 // therefore be correct in the face of uninitialized objects. | |
| 920 size = cl->do_object_careful(oop(addr)); | |
| 921 if (size == 0) { | |
| 922 // An unparsable object found. Signal early termination. | |
| 923 return addr; | |
| 924 } | |
| 925 } | |
| 926 } | |
| 927 return NULL; | |
| 928 } | |
| 929 | |
| 930 // Callers of this iterator beware: The closure application should | |
| 931 // be robust in the face of uninitialized objects and should (always) | |
| 932 // return a correct size so that the next addr + size below gives us a | |
| 933 // valid block boundary. [See for instance, | |
| 934 // ScanMarkedObjectsAgainCarefullyClosure::do_object_careful() | |
| 935 // in ConcurrentMarkSweepGeneration.cpp.] | |
| 936 HeapWord* | |
| 937 CompactibleFreeListSpace::object_iterate_careful_m(MemRegion mr, | |
| 938 ObjectClosureCareful* cl) { | |
| 939 assert_lock_strong(freelistLock()); | |
| 940 // Can't use used_region() below because it may not necessarily | |
| 941 // be the same as [bottom(),end()); although we could | |
| 942 // use [used_region().start(),round_to(used_region().end(),CardSize)), | |
| 943 // that appears too cumbersome, so we just do the simpler check | |
| 944 // in the assertion below. | |
| 945 assert(!mr.is_empty() && MemRegion(bottom(),end()).contains(mr), | |
| 946 "mr should be non-empty and within used space"); | |
| 947 HeapWord *addr, *end; | |
| 948 size_t size; | |
| 949 for (addr = block_start_careful(mr.start()), end = mr.end(); | |
| 950 addr < end; addr += size) { | |
| 951 FreeChunk* fc = (FreeChunk*)addr; | |
| 952 if (fc->isFree()) { | |
| 953 // Since we hold the free list lock, which protects direct | |
| 954 // allocation in this generation by mutators, a free object | |
| 955 // will remain free throughout this iteration code. | |
| 956 size = fc->size(); | |
| 957 } else { | |
| 958 // Note that the object need not necessarily be initialized, | |
| 959 // because (for instance) the free list lock does NOT protect | |
| 960 // object initialization. The closure application below must | |
| 961 // therefore be correct in the face of uninitialized objects. | |
| 962 size = cl->do_object_careful_m(oop(addr), mr); | |
| 963 if (size == 0) { | |
| 964 // An unparsable object found. Signal early termination. | |
| 965 return addr; | |
| 966 } | |
| 967 } | |
| 968 } | |
| 969 return NULL; | |
| 970 } | |
| 971 | |
| 972 | |
|
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973 HeapWord* CompactibleFreeListSpace::block_start_const(const void* p) const { |
| 0 | 974 NOT_PRODUCT(verify_objects_initialized()); |
| 975 return _bt.block_start(p); | |
| 976 } | |
| 977 | |
| 978 HeapWord* CompactibleFreeListSpace::block_start_careful(const void* p) const { | |
| 979 return _bt.block_start_careful(p); | |
| 980 } | |
| 981 | |
| 982 size_t CompactibleFreeListSpace::block_size(const HeapWord* p) const { | |
| 983 NOT_PRODUCT(verify_objects_initialized()); | |
| 984 // This must be volatile, or else there is a danger that the compiler | |
| 985 // will compile the code below into a sometimes-infinite loop, by keeping | |
| 986 // the value read the first time in a register. | |
| 987 while (true) { | |
| 988 // We must do this until we get a consistent view of the object. | |
| 187 | 989 if (FreeChunk::indicatesFreeChunk(p)) { |
| 990 volatile FreeChunk* fc = (volatile FreeChunk*)p; | |
| 991 size_t res = fc->size(); | |
| 992 // If the object is still a free chunk, return the size, else it | |
| 993 // has been allocated so try again. | |
| 994 if (FreeChunk::indicatesFreeChunk(p)) { | |
| 0 | 995 assert(res != 0, "Block size should not be 0"); |
| 996 return res; | |
| 997 } | |
| 187 | 998 } else { |
| 999 // must read from what 'p' points to in each loop. | |
| 1000 klassOop k = ((volatile oopDesc*)p)->klass_or_null(); | |
| 1001 if (k != NULL) { | |
|
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1002 assert(k->is_oop(true /* ignore mark word */), "Should be klass oop"); |
| 187 | 1003 oop o = (oop)p; |
| 1004 assert(o->is_parsable(), "Should be parsable"); | |
| 1005 assert(o->is_oop(true /* ignore mark word */), "Should be an oop."); | |
| 1006 size_t res = o->size_given_klass(k->klass_part()); | |
| 1007 res = adjustObjectSize(res); | |
| 1008 assert(res != 0, "Block size should not be 0"); | |
| 1009 return res; | |
| 1010 } | |
| 0 | 1011 } |
| 1012 } | |
| 1013 } | |
| 1014 | |
| 1015 // A variant of the above that uses the Printezis bits for | |
| 1016 // unparsable but allocated objects. This avoids any possible | |
| 1017 // stalls waiting for mutators to initialize objects, and is | |
| 1018 // thus potentially faster than the variant above. However, | |
| 1019 // this variant may return a zero size for a block that is | |
| 1020 // under mutation and for which a consistent size cannot be | |
| 1021 // inferred without stalling; see CMSCollector::block_size_if_printezis_bits(). | |
| 1022 size_t CompactibleFreeListSpace::block_size_no_stall(HeapWord* p, | |
| 1023 const CMSCollector* c) | |
| 1024 const { | |
| 1025 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 1026 // This must be volatile, or else there is a danger that the compiler | |
| 1027 // will compile the code below into a sometimes-infinite loop, by keeping | |
| 1028 // the value read the first time in a register. | |
| 1029 DEBUG_ONLY(uint loops = 0;) | |
| 1030 while (true) { | |
| 1031 // We must do this until we get a consistent view of the object. | |
| 187 | 1032 if (FreeChunk::indicatesFreeChunk(p)) { |
| 1033 volatile FreeChunk* fc = (volatile FreeChunk*)p; | |
| 1034 size_t res = fc->size(); | |
| 1035 if (FreeChunk::indicatesFreeChunk(p)) { | |
| 0 | 1036 assert(res != 0, "Block size should not be 0"); |
| 1037 assert(loops == 0, "Should be 0"); | |
| 1038 return res; | |
| 1039 } | |
| 1040 } else { | |
| 187 | 1041 // must read from what 'p' points to in each loop. |
| 1042 klassOop k = ((volatile oopDesc*)p)->klass_or_null(); | |
|
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1043 // We trust the size of any object that has a non-NULL |
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1044 // klass and (for those in the perm gen) is parsable |
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1045 // -- irrespective of its conc_safe-ty. |
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1046 if (k != NULL && ((oopDesc*)p)->is_parsable()) { |
| 187 | 1047 assert(k->is_oop(), "Should really be klass oop."); |
| 1048 oop o = (oop)p; | |
| 1049 assert(o->is_oop(), "Should be an oop"); | |
| 1050 size_t res = o->size_given_klass(k->klass_part()); | |
| 1051 res = adjustObjectSize(res); | |
| 1052 assert(res != 0, "Block size should not be 0"); | |
| 1053 return res; | |
| 1054 } else { | |
|
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1055 // May return 0 if P-bits not present. |
| 187 | 1056 return c->block_size_if_printezis_bits(p); |
| 1057 } | |
| 0 | 1058 } |
| 1059 assert(loops == 0, "Can loop at most once"); | |
| 1060 DEBUG_ONLY(loops++;) | |
| 1061 } | |
| 1062 } | |
| 1063 | |
| 1064 size_t CompactibleFreeListSpace::block_size_nopar(const HeapWord* p) const { | |
| 1065 NOT_PRODUCT(verify_objects_initialized()); | |
| 1066 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 1067 FreeChunk* fc = (FreeChunk*)p; | |
| 1068 if (fc->isFree()) { | |
| 1069 return fc->size(); | |
| 1070 } else { | |
| 1071 // Ignore mark word because this may be a recently promoted | |
| 1072 // object whose mark word is used to chain together grey | |
| 1073 // objects (the last one would have a null value). | |
| 1074 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 1075 return adjustObjectSize(oop(p)->size()); | |
| 1076 } | |
| 1077 } | |
| 1078 | |
| 1079 // This implementation assumes that the property of "being an object" is | |
| 1080 // stable. But being a free chunk may not be (because of parallel | |
| 1081 // promotion.) | |
| 1082 bool CompactibleFreeListSpace::block_is_obj(const HeapWord* p) const { | |
| 1083 FreeChunk* fc = (FreeChunk*)p; | |
| 1084 assert(is_in_reserved(p), "Should be in space"); | |
| 1085 // When doing a mark-sweep-compact of the CMS generation, this | |
| 1086 // assertion may fail because prepare_for_compaction() uses | |
| 1087 // space that is garbage to maintain information on ranges of | |
| 1088 // live objects so that these live ranges can be moved as a whole. | |
| 1089 // Comment out this assertion until that problem can be solved | |
| 1090 // (i.e., that the block start calculation may look at objects | |
| 1091 // at address below "p" in finding the object that contains "p" | |
| 1092 // and those objects (if garbage) may have been modified to hold | |
| 1093 // live range information. | |
|
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1094 // assert(CollectedHeap::use_parallel_gc_threads() || _bt.block_start(p) == p, |
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1095 // "Should be a block boundary"); |
| 187 | 1096 if (FreeChunk::indicatesFreeChunk(p)) return false; |
| 1097 klassOop k = oop(p)->klass_or_null(); | |
| 0 | 1098 if (k != NULL) { |
| 1099 // Ignore mark word because it may have been used to | |
| 1100 // chain together promoted objects (the last one | |
| 1101 // would have a null value). | |
| 1102 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 1103 return true; | |
| 1104 } else { | |
| 1105 return false; // Was not an object at the start of collection. | |
| 1106 } | |
| 1107 } | |
| 1108 | |
| 1109 // Check if the object is alive. This fact is checked either by consulting | |
| 1110 // the main marking bitmap in the sweeping phase or, if it's a permanent | |
| 1111 // generation and we're not in the sweeping phase, by checking the | |
| 1112 // perm_gen_verify_bit_map where we store the "deadness" information if | |
| 1113 // we did not sweep the perm gen in the most recent previous GC cycle. | |
| 1114 bool CompactibleFreeListSpace::obj_is_alive(const HeapWord* p) const { | |
|
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1115 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(), |
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1116 "Else races are possible"); |
|
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1117 assert(block_is_obj(p), "The address should point to an object"); |
| 0 | 1118 |
| 1119 // If we're sweeping, we use object liveness information from the main bit map | |
| 1120 // for both perm gen and old gen. | |
| 1121 // We don't need to lock the bitmap (live_map or dead_map below), because | |
| 1122 // EITHER we are in the middle of the sweeping phase, and the | |
| 1123 // main marking bit map (live_map below) is locked, | |
| 1124 // OR we're in other phases and perm_gen_verify_bit_map (dead_map below) | |
| 1125 // is stable, because it's mutated only in the sweeping phase. | |
|
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1126 // NOTE: This method is also used by jmap where, if class unloading is |
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1127 // off, the results can return "false" for legitimate perm objects, |
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1128 // when we are not in the midst of a sweeping phase, which can result |
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1129 // in jmap not reporting certain perm gen objects. This will be moot |
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1130 // if/when the perm gen goes away in the future. |
| 0 | 1131 if (_collector->abstract_state() == CMSCollector::Sweeping) { |
| 1132 CMSBitMap* live_map = _collector->markBitMap(); | |
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1133 return live_map->par_isMarked((HeapWord*) p); |
| 0 | 1134 } else { |
| 1135 // If we're not currently sweeping and we haven't swept the perm gen in | |
| 1136 // the previous concurrent cycle then we may have dead but unswept objects | |
| 1137 // in the perm gen. In this case, we use the "deadness" information | |
| 1138 // that we had saved in perm_gen_verify_bit_map at the last sweep. | |
| 1139 if (!CMSClassUnloadingEnabled && _collector->_permGen->reserved().contains(p)) { | |
| 1140 if (_collector->verifying()) { | |
| 1141 CMSBitMap* dead_map = _collector->perm_gen_verify_bit_map(); | |
| 1142 // Object is marked in the dead_map bitmap at the previous sweep | |
| 1143 // when we know that it's dead; if the bitmap is not allocated then | |
| 1144 // the object is alive. | |
| 1145 return (dead_map->sizeInBits() == 0) // bit_map has been allocated | |
| 1146 || !dead_map->par_isMarked((HeapWord*) p); | |
| 1147 } else { | |
| 1148 return false; // We can't say for sure if it's live, so we say that it's dead. | |
| 1149 } | |
| 1150 } | |
| 1151 } | |
| 1152 return true; | |
| 1153 } | |
| 1154 | |
| 1155 bool CompactibleFreeListSpace::block_is_obj_nopar(const HeapWord* p) const { | |
| 1156 FreeChunk* fc = (FreeChunk*)p; | |
| 1157 assert(is_in_reserved(p), "Should be in space"); | |
| 1158 assert(_bt.block_start(p) == p, "Should be a block boundary"); | |
| 1159 if (!fc->isFree()) { | |
| 1160 // Ignore mark word because it may have been used to | |
| 1161 // chain together promoted objects (the last one | |
| 1162 // would have a null value). | |
| 1163 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 1164 return true; | |
| 1165 } | |
| 1166 return false; | |
| 1167 } | |
| 1168 | |
| 1169 // "MT-safe but not guaranteed MT-precise" (TM); you may get an | |
| 1170 // approximate answer if you don't hold the freelistlock when you call this. | |
| 1171 size_t CompactibleFreeListSpace::totalSizeInIndexedFreeLists() const { | |
| 1172 size_t size = 0; | |
| 1173 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 1174 debug_only( | |
| 1175 // We may be calling here without the lock in which case we | |
| 1176 // won't do this modest sanity check. | |
| 1177 if (freelistLock()->owned_by_self()) { | |
| 1178 size_t total_list_size = 0; | |
| 1179 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 1180 fc = fc->next()) { | |
| 1181 total_list_size += i; | |
| 1182 } | |
| 1183 assert(total_list_size == i * _indexedFreeList[i].count(), | |
| 1184 "Count in list is incorrect"); | |
| 1185 } | |
| 1186 ) | |
| 1187 size += i * _indexedFreeList[i].count(); | |
| 1188 } | |
| 1189 return size; | |
| 1190 } | |
| 1191 | |
| 1192 HeapWord* CompactibleFreeListSpace::par_allocate(size_t size) { | |
| 1193 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 1194 return allocate(size); | |
| 1195 } | |
| 1196 | |
| 1197 HeapWord* | |
| 1198 CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlockRemainder(size_t size) { | |
| 1199 return getChunkFromLinearAllocBlockRemainder(&_smallLinearAllocBlock, size); | |
| 1200 } | |
| 1201 | |
| 1202 HeapWord* CompactibleFreeListSpace::allocate(size_t size) { | |
| 1203 assert_lock_strong(freelistLock()); | |
| 1204 HeapWord* res = NULL; | |
| 1205 assert(size == adjustObjectSize(size), | |
| 1206 "use adjustObjectSize() before calling into allocate()"); | |
| 1207 | |
| 1208 if (_adaptive_freelists) { | |
| 1209 res = allocate_adaptive_freelists(size); | |
| 1210 } else { // non-adaptive free lists | |
| 1211 res = allocate_non_adaptive_freelists(size); | |
| 1212 } | |
| 1213 | |
| 1214 if (res != NULL) { | |
| 1215 // check that res does lie in this space! | |
| 1216 assert(is_in_reserved(res), "Not in this space!"); | |
| 1217 assert(is_aligned((void*)res), "alignment check"); | |
| 1218 | |
| 1219 FreeChunk* fc = (FreeChunk*)res; | |
| 1220 fc->markNotFree(); | |
| 1221 assert(!fc->isFree(), "shouldn't be marked free"); | |
| 187 | 1222 assert(oop(fc)->klass_or_null() == NULL, "should look uninitialized"); |
| 0 | 1223 // Verify that the block offset table shows this to |
| 1224 // be a single block, but not one which is unallocated. | |
| 1225 _bt.verify_single_block(res, size); | |
| 1226 _bt.verify_not_unallocated(res, size); | |
| 1227 // mangle a just allocated object with a distinct pattern. | |
| 1228 debug_only(fc->mangleAllocated(size)); | |
| 1229 } | |
| 1230 | |
| 1231 return res; | |
| 1232 } | |
| 1233 | |
| 1234 HeapWord* CompactibleFreeListSpace::allocate_non_adaptive_freelists(size_t size) { | |
| 1235 HeapWord* res = NULL; | |
| 1236 // try and use linear allocation for smaller blocks | |
| 1237 if (size < _smallLinearAllocBlock._allocation_size_limit) { | |
| 1238 // if successful, the following also adjusts block offset table | |
| 1239 res = getChunkFromSmallLinearAllocBlock(size); | |
| 1240 } | |
| 1241 // Else triage to indexed lists for smaller sizes | |
| 1242 if (res == NULL) { | |
| 1243 if (size < SmallForDictionary) { | |
| 1244 res = (HeapWord*) getChunkFromIndexedFreeList(size); | |
| 1245 } else { | |
| 1246 // else get it from the big dictionary; if even this doesn't | |
| 1247 // work we are out of luck. | |
| 1248 res = (HeapWord*)getChunkFromDictionaryExact(size); | |
| 1249 } | |
| 1250 } | |
| 1251 | |
| 1252 return res; | |
| 1253 } | |
| 1254 | |
| 1255 HeapWord* CompactibleFreeListSpace::allocate_adaptive_freelists(size_t size) { | |
| 1256 assert_lock_strong(freelistLock()); | |
| 1257 HeapWord* res = NULL; | |
| 1258 assert(size == adjustObjectSize(size), | |
| 1259 "use adjustObjectSize() before calling into allocate()"); | |
| 1260 | |
| 1261 // Strategy | |
| 1262 // if small | |
| 1263 // exact size from small object indexed list if small | |
| 1264 // small or large linear allocation block (linAB) as appropriate | |
| 1265 // take from lists of greater sized chunks | |
| 1266 // else | |
| 1267 // dictionary | |
| 1268 // small or large linear allocation block if it has the space | |
| 1269 // Try allocating exact size from indexTable first | |
| 1270 if (size < IndexSetSize) { | |
| 1271 res = (HeapWord*) getChunkFromIndexedFreeList(size); | |
| 1272 if(res != NULL) { | |
| 1273 assert(res != (HeapWord*)_indexedFreeList[size].head(), | |
| 1274 "Not removed from free list"); | |
| 1275 // no block offset table adjustment is necessary on blocks in | |
| 1276 // the indexed lists. | |
| 1277 | |
| 1278 // Try allocating from the small LinAB | |
| 1279 } else if (size < _smallLinearAllocBlock._allocation_size_limit && | |
| 1280 (res = getChunkFromSmallLinearAllocBlock(size)) != NULL) { | |
| 1281 // if successful, the above also adjusts block offset table | |
| 1282 // Note that this call will refill the LinAB to | |
| 1283 // satisfy the request. This is different that | |
| 1284 // evm. | |
| 1285 // Don't record chunk off a LinAB? smallSplitBirth(size); | |
| 1286 } else { | |
| 1287 // Raid the exact free lists larger than size, even if they are not | |
| 1288 // overpopulated. | |
| 1289 res = (HeapWord*) getChunkFromGreater(size); | |
| 1290 } | |
| 1291 } else { | |
| 1292 // Big objects get allocated directly from the dictionary. | |
| 1293 res = (HeapWord*) getChunkFromDictionaryExact(size); | |
| 1294 if (res == NULL) { | |
| 1295 // Try hard not to fail since an allocation failure will likely | |
| 1296 // trigger a synchronous GC. Try to get the space from the | |
| 1297 // allocation blocks. | |
| 1298 res = getChunkFromSmallLinearAllocBlockRemainder(size); | |
| 1299 } | |
| 1300 } | |
| 1301 | |
| 1302 return res; | |
| 1303 } | |
| 1304 | |
| 1305 // A worst-case estimate of the space required (in HeapWords) to expand the heap | |
| 1306 // when promoting obj. | |
| 1307 size_t CompactibleFreeListSpace::expansionSpaceRequired(size_t obj_size) const { | |
| 1308 // Depending on the object size, expansion may require refilling either a | |
| 1309 // bigLAB or a smallLAB plus refilling a PromotionInfo object. MinChunkSize | |
| 1310 // is added because the dictionary may over-allocate to avoid fragmentation. | |
| 1311 size_t space = obj_size; | |
| 1312 if (!_adaptive_freelists) { | |
| 1313 space = MAX2(space, _smallLinearAllocBlock._refillSize); | |
| 1314 } | |
| 1315 space += _promoInfo.refillSize() + 2 * MinChunkSize; | |
| 1316 return space; | |
| 1317 } | |
| 1318 | |
| 1319 FreeChunk* CompactibleFreeListSpace::getChunkFromGreater(size_t numWords) { | |
| 1320 FreeChunk* ret; | |
| 1321 | |
| 1322 assert(numWords >= MinChunkSize, "Size is less than minimum"); | |
| 1323 assert(linearAllocationWouldFail() || bestFitFirst(), | |
| 1324 "Should not be here"); | |
| 1325 | |
| 1326 size_t i; | |
| 1327 size_t currSize = numWords + MinChunkSize; | |
| 1328 assert(currSize % MinObjAlignment == 0, "currSize should be aligned"); | |
| 1329 for (i = currSize; i < IndexSetSize; i += IndexSetStride) { | |
| 1330 FreeList* fl = &_indexedFreeList[i]; | |
| 1331 if (fl->head()) { | |
| 1332 ret = getFromListGreater(fl, numWords); | |
| 1333 assert(ret == NULL || ret->isFree(), "Should be returning a free chunk"); | |
| 1334 return ret; | |
| 1335 } | |
| 1336 } | |
| 1337 | |
| 1338 currSize = MAX2((size_t)SmallForDictionary, | |
| 1339 (size_t)(numWords + MinChunkSize)); | |
| 1340 | |
| 1341 /* Try to get a chunk that satisfies request, while avoiding | |
| 1342 fragmentation that can't be handled. */ | |
| 1343 { | |
| 1344 ret = dictionary()->getChunk(currSize); | |
| 1345 if (ret != NULL) { | |
| 1346 assert(ret->size() - numWords >= MinChunkSize, | |
| 1347 "Chunk is too small"); | |
| 1348 _bt.allocated((HeapWord*)ret, ret->size()); | |
| 1349 /* Carve returned chunk. */ | |
| 1350 (void) splitChunkAndReturnRemainder(ret, numWords); | |
| 1351 /* Label this as no longer a free chunk. */ | |
| 1352 assert(ret->isFree(), "This chunk should be free"); | |
| 1353 ret->linkPrev(NULL); | |
| 1354 } | |
| 1355 assert(ret == NULL || ret->isFree(), "Should be returning a free chunk"); | |
| 1356 return ret; | |
| 1357 } | |
| 1358 ShouldNotReachHere(); | |
| 1359 } | |
| 1360 | |
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1361 bool CompactibleFreeListSpace::verifyChunkInIndexedFreeLists(FreeChunk* fc) const { |
| 0 | 1362 assert(fc->size() < IndexSetSize, "Size of chunk is too large"); |
| 1363 return _indexedFreeList[fc->size()].verifyChunkInFreeLists(fc); | |
| 1364 } | |
| 1365 | |
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1366 bool CompactibleFreeListSpace::verify_chunk_is_linear_alloc_block(FreeChunk* fc) const { |
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1367 assert((_smallLinearAllocBlock._ptr != (HeapWord*)fc) || |
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1368 (_smallLinearAllocBlock._word_size == fc->size()), |
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1369 "Linear allocation block shows incorrect size"); |
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1370 return ((_smallLinearAllocBlock._ptr == (HeapWord*)fc) && |
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1371 (_smallLinearAllocBlock._word_size == fc->size())); |
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1372 } |
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1373 |
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1374 // Check if the purported free chunk is present either as a linear |
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1375 // allocation block, the size-indexed table of (smaller) free blocks, |
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1376 // or the larger free blocks kept in the binary tree dictionary. |
| 0 | 1377 bool CompactibleFreeListSpace::verifyChunkInFreeLists(FreeChunk* fc) const { |
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1378 if (verify_chunk_is_linear_alloc_block(fc)) { |
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1379 return true; |
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1380 } else if (fc->size() < IndexSetSize) { |
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1381 return verifyChunkInIndexedFreeLists(fc); |
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1382 } else { |
| 0 | 1383 return dictionary()->verifyChunkInFreeLists(fc); |
| 1384 } | |
| 1385 } | |
| 1386 | |
| 1387 #ifndef PRODUCT | |
| 1388 void CompactibleFreeListSpace::assert_locked() const { | |
| 1389 CMSLockVerifier::assert_locked(freelistLock(), parDictionaryAllocLock()); | |
| 1390 } | |
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1391 |
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1392 void CompactibleFreeListSpace::assert_locked(const Mutex* lock) const { |
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1393 CMSLockVerifier::assert_locked(lock); |
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1394 } |
| 0 | 1395 #endif |
| 1396 | |
| 1397 FreeChunk* CompactibleFreeListSpace::allocateScratch(size_t size) { | |
| 1398 // In the parallel case, the main thread holds the free list lock | |
| 1399 // on behalf the parallel threads. | |
| 1400 FreeChunk* fc; | |
| 1401 { | |
| 1402 // If GC is parallel, this might be called by several threads. | |
| 1403 // This should be rare enough that the locking overhead won't affect | |
| 1404 // the sequential code. | |
| 1405 MutexLockerEx x(parDictionaryAllocLock(), | |
| 1406 Mutex::_no_safepoint_check_flag); | |
| 1407 fc = getChunkFromDictionary(size); | |
| 1408 } | |
| 1409 if (fc != NULL) { | |
| 1410 fc->dontCoalesce(); | |
| 1411 assert(fc->isFree(), "Should be free, but not coalescable"); | |
| 1412 // Verify that the block offset table shows this to | |
| 1413 // be a single block, but not one which is unallocated. | |
| 1414 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 1415 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 1416 } | |
| 1417 return fc; | |
| 1418 } | |
| 1419 | |
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1420 oop CompactibleFreeListSpace::promote(oop obj, size_t obj_size) { |
| 0 | 1421 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); |
| 1422 assert_locked(); | |
| 1423 | |
| 1424 // if we are tracking promotions, then first ensure space for | |
| 1425 // promotion (including spooling space for saving header if necessary). | |
| 1426 // then allocate and copy, then track promoted info if needed. | |
| 1427 // When tracking (see PromotionInfo::track()), the mark word may | |
| 1428 // be displaced and in this case restoration of the mark word | |
| 1429 // occurs in the (oop_since_save_marks_)iterate phase. | |
| 1430 if (_promoInfo.tracking() && !_promoInfo.ensure_spooling_space()) { | |
| 1431 return NULL; | |
| 1432 } | |
| 1433 // Call the allocate(size_t, bool) form directly to avoid the | |
| 1434 // additional call through the allocate(size_t) form. Having | |
| 1435 // the compile inline the call is problematic because allocate(size_t) | |
| 1436 // is a virtual method. | |
| 1437 HeapWord* res = allocate(adjustObjectSize(obj_size)); | |
| 1438 if (res != NULL) { | |
| 1439 Copy::aligned_disjoint_words((HeapWord*)obj, res, obj_size); | |
| 1440 // if we should be tracking promotions, do so. | |
| 1441 if (_promoInfo.tracking()) { | |
| 1442 _promoInfo.track((PromotedObject*)res); | |
| 1443 } | |
| 1444 } | |
| 1445 return oop(res); | |
| 1446 } | |
| 1447 | |
| 1448 HeapWord* | |
| 1449 CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlock(size_t size) { | |
| 1450 assert_locked(); | |
| 1451 assert(size >= MinChunkSize, "minimum chunk size"); | |
| 1452 assert(size < _smallLinearAllocBlock._allocation_size_limit, | |
| 1453 "maximum from smallLinearAllocBlock"); | |
| 1454 return getChunkFromLinearAllocBlock(&_smallLinearAllocBlock, size); | |
| 1455 } | |
| 1456 | |
| 1457 HeapWord* | |
| 1458 CompactibleFreeListSpace::getChunkFromLinearAllocBlock(LinearAllocBlock *blk, | |
| 1459 size_t size) { | |
| 1460 assert_locked(); | |
| 1461 assert(size >= MinChunkSize, "too small"); | |
| 1462 HeapWord* res = NULL; | |
| 1463 // Try to do linear allocation from blk, making sure that | |
| 1464 if (blk->_word_size == 0) { | |
| 1465 // We have probably been unable to fill this either in the prologue or | |
| 1466 // when it was exhausted at the last linear allocation. Bail out until | |
| 1467 // next time. | |
| 1468 assert(blk->_ptr == NULL, "consistency check"); | |
| 1469 return NULL; | |
| 1470 } | |
| 1471 assert(blk->_word_size != 0 && blk->_ptr != NULL, "consistency check"); | |
| 1472 res = getChunkFromLinearAllocBlockRemainder(blk, size); | |
| 1473 if (res != NULL) return res; | |
| 1474 | |
| 1475 // about to exhaust this linear allocation block | |
| 1476 if (blk->_word_size == size) { // exactly satisfied | |
| 1477 res = blk->_ptr; | |
| 1478 _bt.allocated(res, blk->_word_size); | |
| 1479 } else if (size + MinChunkSize <= blk->_refillSize) { | |
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1480 size_t sz = blk->_word_size; |
| 0 | 1481 // Update _unallocated_block if the size is such that chunk would be |
| 1482 // returned to the indexed free list. All other chunks in the indexed | |
| 1483 // free lists are allocated from the dictionary so that _unallocated_block | |
| 1484 // has already been adjusted for them. Do it here so that the cost | |
| 1485 // for all chunks added back to the indexed free lists. | |
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1486 if (sz < SmallForDictionary) { |
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1487 _bt.allocated(blk->_ptr, sz); |
| 0 | 1488 } |
| 1489 // Return the chunk that isn't big enough, and then refill below. | |
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1490 addChunkToFreeLists(blk->_ptr, sz); |
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1491 splitBirth(sz); |
| 0 | 1492 // Don't keep statistics on adding back chunk from a LinAB. |
| 1493 } else { | |
| 1494 // A refilled block would not satisfy the request. | |
| 1495 return NULL; | |
| 1496 } | |
| 1497 | |
| 1498 blk->_ptr = NULL; blk->_word_size = 0; | |
| 1499 refillLinearAllocBlock(blk); | |
| 1500 assert(blk->_ptr == NULL || blk->_word_size >= size + MinChunkSize, | |
| 1501 "block was replenished"); | |
| 1502 if (res != NULL) { | |
| 1503 splitBirth(size); | |
| 1504 repairLinearAllocBlock(blk); | |
| 1505 } else if (blk->_ptr != NULL) { | |
| 1506 res = blk->_ptr; | |
| 1507 size_t blk_size = blk->_word_size; | |
| 1508 blk->_word_size -= size; | |
| 1509 blk->_ptr += size; | |
| 1510 splitBirth(size); | |
| 1511 repairLinearAllocBlock(blk); | |
| 1512 // Update BOT last so that other (parallel) GC threads see a consistent | |
| 1513 // view of the BOT and free blocks. | |
| 1514 // Above must occur before BOT is updated below. | |
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1515 OrderAccess::storestore(); |
| 0 | 1516 _bt.split_block(res, blk_size, size); // adjust block offset table |
| 1517 } | |
| 1518 return res; | |
| 1519 } | |
| 1520 | |
| 1521 HeapWord* CompactibleFreeListSpace::getChunkFromLinearAllocBlockRemainder( | |
| 1522 LinearAllocBlock* blk, | |
| 1523 size_t size) { | |
| 1524 assert_locked(); | |
| 1525 assert(size >= MinChunkSize, "too small"); | |
| 1526 | |
| 1527 HeapWord* res = NULL; | |
| 1528 // This is the common case. Keep it simple. | |
| 1529 if (blk->_word_size >= size + MinChunkSize) { | |
| 1530 assert(blk->_ptr != NULL, "consistency check"); | |
| 1531 res = blk->_ptr; | |
| 1532 // Note that the BOT is up-to-date for the linAB before allocation. It | |
| 1533 // indicates the start of the linAB. The split_block() updates the | |
| 1534 // BOT for the linAB after the allocation (indicates the start of the | |
| 1535 // next chunk to be allocated). | |
| 1536 size_t blk_size = blk->_word_size; | |
| 1537 blk->_word_size -= size; | |
| 1538 blk->_ptr += size; | |
| 1539 splitBirth(size); | |
| 1540 repairLinearAllocBlock(blk); | |
| 1541 // Update BOT last so that other (parallel) GC threads see a consistent | |
| 1542 // view of the BOT and free blocks. | |
| 1543 // Above must occur before BOT is updated below. | |
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1544 OrderAccess::storestore(); |
| 0 | 1545 _bt.split_block(res, blk_size, size); // adjust block offset table |
| 1546 _bt.allocated(res, size); | |
| 1547 } | |
| 1548 return res; | |
| 1549 } | |
| 1550 | |
| 1551 FreeChunk* | |
| 1552 CompactibleFreeListSpace::getChunkFromIndexedFreeList(size_t size) { | |
| 1553 assert_locked(); | |
| 1554 assert(size < SmallForDictionary, "just checking"); | |
| 1555 FreeChunk* res; | |
| 1556 res = _indexedFreeList[size].getChunkAtHead(); | |
| 1557 if (res == NULL) { | |
| 1558 res = getChunkFromIndexedFreeListHelper(size); | |
| 1559 } | |
| 1560 _bt.verify_not_unallocated((HeapWord*) res, size); | |
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1561 assert(res == NULL || res->size() == size, "Incorrect block size"); |
| 0 | 1562 return res; |
| 1563 } | |
| 1564 | |
| 1565 FreeChunk* | |
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1566 CompactibleFreeListSpace::getChunkFromIndexedFreeListHelper(size_t size, |
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1567 bool replenish) { |
| 0 | 1568 assert_locked(); |
| 1569 FreeChunk* fc = NULL; | |
| 1570 if (size < SmallForDictionary) { | |
| 1571 assert(_indexedFreeList[size].head() == NULL || | |
| 1572 _indexedFreeList[size].surplus() <= 0, | |
| 1573 "List for this size should be empty or under populated"); | |
| 1574 // Try best fit in exact lists before replenishing the list | |
| 1575 if (!bestFitFirst() || (fc = bestFitSmall(size)) == NULL) { | |
| 1576 // Replenish list. | |
| 1577 // | |
| 1578 // Things tried that failed. | |
| 1579 // Tried allocating out of the two LinAB's first before | |
| 1580 // replenishing lists. | |
| 1581 // Tried small linAB of size 256 (size in indexed list) | |
| 1582 // and replenishing indexed lists from the small linAB. | |
| 1583 // | |
| 1584 FreeChunk* newFc = NULL; | |
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1585 const size_t replenish_size = CMSIndexedFreeListReplenish * size; |
| 0 | 1586 if (replenish_size < SmallForDictionary) { |
| 1587 // Do not replenish from an underpopulated size. | |
| 1588 if (_indexedFreeList[replenish_size].surplus() > 0 && | |
| 1589 _indexedFreeList[replenish_size].head() != NULL) { | |
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1590 newFc = _indexedFreeList[replenish_size].getChunkAtHead(); |
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1591 } else if (bestFitFirst()) { |
| 0 | 1592 newFc = bestFitSmall(replenish_size); |
| 1593 } | |
| 1594 } | |
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1595 if (newFc == NULL && replenish_size > size) { |
| 0 | 1596 assert(CMSIndexedFreeListReplenish > 1, "ctl pt invariant"); |
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1597 newFc = getChunkFromIndexedFreeListHelper(replenish_size, false); |
| 0 | 1598 } |
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1599 // Note: The stats update re split-death of block obtained above |
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1600 // will be recorded below precisely when we know we are going to |
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1601 // be actually splitting it into more than one pieces below. |
| 0 | 1602 if (newFc != NULL) { |
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1603 if (replenish || CMSReplenishIntermediate) { |
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1604 // Replenish this list and return one block to caller. |
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1605 size_t i; |
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1606 FreeChunk *curFc, *nextFc; |
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1607 size_t num_blk = newFc->size() / size; |
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1608 assert(num_blk >= 1, "Smaller than requested?"); |
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1609 assert(newFc->size() % size == 0, "Should be integral multiple of request"); |
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1610 if (num_blk > 1) { |
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1611 // we are sure we will be splitting the block just obtained |
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1612 // into multiple pieces; record the split-death of the original |
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1613 splitDeath(replenish_size); |
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1614 } |
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1615 // carve up and link blocks 0, ..., num_blk - 2 |
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1616 // The last chunk is not added to the lists but is returned as the |
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1617 // free chunk. |
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1618 for (curFc = newFc, nextFc = (FreeChunk*)((HeapWord*)curFc + size), |
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1619 i = 0; |
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1620 i < (num_blk - 1); |
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1621 curFc = nextFc, nextFc = (FreeChunk*)((HeapWord*)nextFc + size), |
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1622 i++) { |
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1623 curFc->setSize(size); |
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1624 // Don't record this as a return in order to try and |
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1625 // determine the "returns" from a GC. |
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1626 _bt.verify_not_unallocated((HeapWord*) fc, size); |
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1627 _indexedFreeList[size].returnChunkAtTail(curFc, false); |
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1628 _bt.mark_block((HeapWord*)curFc, size); |
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1629 splitBirth(size); |
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1630 // Don't record the initial population of the indexed list |
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1631 // as a split birth. |
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1632 } |
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1633 |
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1634 // check that the arithmetic was OK above |
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1635 assert((HeapWord*)nextFc == (HeapWord*)newFc + num_blk*size, |
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1636 "inconsistency in carving newFc"); |
| 0 | 1637 curFc->setSize(size); |
| 1638 _bt.mark_block((HeapWord*)curFc, size); | |
| 1639 splitBirth(size); | |
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1640 fc = curFc; |
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1641 } else { |
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1642 // Return entire block to caller |
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1643 fc = newFc; |
| 0 | 1644 } |
| 1645 } | |
| 1646 } | |
| 1647 } else { | |
| 1648 // Get a free chunk from the free chunk dictionary to be returned to | |
| 1649 // replenish the indexed free list. | |
| 1650 fc = getChunkFromDictionaryExact(size); | |
| 1651 } | |
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1652 // assert(fc == NULL || fc->isFree(), "Should be returning a free chunk"); |
| 0 | 1653 return fc; |
| 1654 } | |
| 1655 | |
| 1656 FreeChunk* | |
| 1657 CompactibleFreeListSpace::getChunkFromDictionary(size_t size) { | |
| 1658 assert_locked(); | |
| 1659 FreeChunk* fc = _dictionary->getChunk(size); | |
| 1660 if (fc == NULL) { | |
| 1661 return NULL; | |
| 1662 } | |
| 1663 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1664 if (fc->size() >= size + MinChunkSize) { | |
| 1665 fc = splitChunkAndReturnRemainder(fc, size); | |
| 1666 } | |
| 1667 assert(fc->size() >= size, "chunk too small"); | |
| 1668 assert(fc->size() < size + MinChunkSize, "chunk too big"); | |
| 1669 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 1670 return fc; | |
| 1671 } | |
| 1672 | |
| 1673 FreeChunk* | |
| 1674 CompactibleFreeListSpace::getChunkFromDictionaryExact(size_t size) { | |
| 1675 assert_locked(); | |
| 1676 FreeChunk* fc = _dictionary->getChunk(size); | |
| 1677 if (fc == NULL) { | |
| 1678 return fc; | |
| 1679 } | |
| 1680 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1681 if (fc->size() == size) { | |
| 1682 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1683 return fc; | |
| 1684 } | |
| 1685 assert(fc->size() > size, "getChunk() guarantee"); | |
| 1686 if (fc->size() < size + MinChunkSize) { | |
| 1687 // Return the chunk to the dictionary and go get a bigger one. | |
| 1688 returnChunkToDictionary(fc); | |
| 1689 fc = _dictionary->getChunk(size + MinChunkSize); | |
| 1690 if (fc == NULL) { | |
| 1691 return NULL; | |
| 1692 } | |
| 1693 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1694 } | |
| 1695 assert(fc->size() >= size + MinChunkSize, "tautology"); | |
| 1696 fc = splitChunkAndReturnRemainder(fc, size); | |
| 1697 assert(fc->size() == size, "chunk is wrong size"); | |
| 1698 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1699 return fc; | |
| 1700 } | |
| 1701 | |
| 1702 void | |
| 1703 CompactibleFreeListSpace::returnChunkToDictionary(FreeChunk* chunk) { | |
| 1704 assert_locked(); | |
| 1705 | |
| 1706 size_t size = chunk->size(); | |
| 1707 _bt.verify_single_block((HeapWord*)chunk, size); | |
| 1708 // adjust _unallocated_block downward, as necessary | |
| 1709 _bt.freed((HeapWord*)chunk, size); | |
| 1710 _dictionary->returnChunk(chunk); | |
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1711 #ifndef PRODUCT |
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1712 if (CMSCollector::abstract_state() != CMSCollector::Sweeping) { |
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1713 TreeChunk::as_TreeChunk(chunk)->list()->verify_stats(); |
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1714 } |
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1715 #endif // PRODUCT |
| 0 | 1716 } |
| 1717 | |
| 1718 void | |
| 1719 CompactibleFreeListSpace::returnChunkToFreeList(FreeChunk* fc) { | |
| 1720 assert_locked(); | |
| 1721 size_t size = fc->size(); | |
| 1722 _bt.verify_single_block((HeapWord*) fc, size); | |
| 1723 _bt.verify_not_unallocated((HeapWord*) fc, size); | |
| 1724 if (_adaptive_freelists) { | |
| 1725 _indexedFreeList[size].returnChunkAtTail(fc); | |
| 1726 } else { | |
| 1727 _indexedFreeList[size].returnChunkAtHead(fc); | |
| 1728 } | |
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1729 #ifndef PRODUCT |
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1730 if (CMSCollector::abstract_state() != CMSCollector::Sweeping) { |
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1731 _indexedFreeList[size].verify_stats(); |
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1732 } |
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1733 #endif // PRODUCT |
| 0 | 1734 } |
| 1735 | |
| 1736 // Add chunk to end of last block -- if it's the largest | |
| 1737 // block -- and update BOT and census data. We would | |
| 1738 // of course have preferred to coalesce it with the | |
| 1739 // last block, but it's currently less expensive to find the | |
| 1740 // largest block than it is to find the last. | |
| 1741 void | |
| 1742 CompactibleFreeListSpace::addChunkToFreeListsAtEndRecordingStats( | |
| 1743 HeapWord* chunk, size_t size) { | |
| 1744 // check that the chunk does lie in this space! | |
| 1745 assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!"); | |
| 1746 // One of the parallel gc task threads may be here | |
| 1747 // whilst others are allocating. | |
| 1748 Mutex* lock = NULL; | |
| 1749 if (ParallelGCThreads != 0) { | |
| 1750 lock = &_parDictionaryAllocLock; | |
| 1751 } | |
| 1752 FreeChunk* ec; | |
| 1753 { | |
| 1754 MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag); | |
| 1755 ec = dictionary()->findLargestDict(); // get largest block | |
| 1756 if (ec != NULL && ec->end() == chunk) { | |
| 1757 // It's a coterminal block - we can coalesce. | |
| 1758 size_t old_size = ec->size(); | |
| 1759 coalDeath(old_size); | |
| 1760 removeChunkFromDictionary(ec); | |
| 1761 size += old_size; | |
| 1762 } else { | |
| 1763 ec = (FreeChunk*)chunk; | |
| 1764 } | |
| 1765 } | |
| 1766 ec->setSize(size); | |
| 1767 debug_only(ec->mangleFreed(size)); | |
| 1768 if (size < SmallForDictionary) { | |
| 1769 lock = _indexedFreeListParLocks[size]; | |
| 1770 } | |
| 1771 MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag); | |
| 1772 addChunkAndRepairOffsetTable((HeapWord*)ec, size, true); | |
| 1773 // record the birth under the lock since the recording involves | |
| 1774 // manipulation of the list on which the chunk lives and | |
| 1775 // if the chunk is allocated and is the last on the list, | |
| 1776 // the list can go away. | |
| 1777 coalBirth(size); | |
| 1778 } | |
| 1779 | |
| 1780 void | |
| 1781 CompactibleFreeListSpace::addChunkToFreeLists(HeapWord* chunk, | |
| 1782 size_t size) { | |
| 1783 // check that the chunk does lie in this space! | |
| 1784 assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!"); | |
| 1785 assert_locked(); | |
| 1786 _bt.verify_single_block(chunk, size); | |
| 1787 | |
| 1788 FreeChunk* fc = (FreeChunk*) chunk; | |
| 1789 fc->setSize(size); | |
| 1790 debug_only(fc->mangleFreed(size)); | |
| 1791 if (size < SmallForDictionary) { | |
| 1792 returnChunkToFreeList(fc); | |
| 1793 } else { | |
| 1794 returnChunkToDictionary(fc); | |
| 1795 } | |
| 1796 } | |
| 1797 | |
| 1798 void | |
| 1799 CompactibleFreeListSpace::addChunkAndRepairOffsetTable(HeapWord* chunk, | |
| 1800 size_t size, bool coalesced) { | |
| 1801 assert_locked(); | |
| 1802 assert(chunk != NULL, "null chunk"); | |
| 1803 if (coalesced) { | |
| 1804 // repair BOT | |
| 1805 _bt.single_block(chunk, size); | |
| 1806 } | |
| 1807 addChunkToFreeLists(chunk, size); | |
| 1808 } | |
| 1809 | |
| 1810 // We _must_ find the purported chunk on our free lists; | |
| 1811 // we assert if we don't. | |
| 1812 void | |
| 1813 CompactibleFreeListSpace::removeFreeChunkFromFreeLists(FreeChunk* fc) { | |
| 1814 size_t size = fc->size(); | |
| 1815 assert_locked(); | |
| 1816 debug_only(verifyFreeLists()); | |
| 1817 if (size < SmallForDictionary) { | |
| 1818 removeChunkFromIndexedFreeList(fc); | |
| 1819 } else { | |
| 1820 removeChunkFromDictionary(fc); | |
| 1821 } | |
| 1822 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1823 debug_only(verifyFreeLists()); | |
| 1824 } | |
| 1825 | |
| 1826 void | |
| 1827 CompactibleFreeListSpace::removeChunkFromDictionary(FreeChunk* fc) { | |
| 1828 size_t size = fc->size(); | |
| 1829 assert_locked(); | |
| 1830 assert(fc != NULL, "null chunk"); | |
| 1831 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1832 _dictionary->removeChunk(fc); | |
| 1833 // adjust _unallocated_block upward, as necessary | |
| 1834 _bt.allocated((HeapWord*)fc, size); | |
| 1835 } | |
| 1836 | |
| 1837 void | |
| 1838 CompactibleFreeListSpace::removeChunkFromIndexedFreeList(FreeChunk* fc) { | |
| 1839 assert_locked(); | |
| 1840 size_t size = fc->size(); | |
| 1841 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1842 NOT_PRODUCT( | |
| 1843 if (FLSVerifyIndexTable) { | |
| 1844 verifyIndexedFreeList(size); | |
| 1845 } | |
| 1846 ) | |
| 1847 _indexedFreeList[size].removeChunk(fc); | |
| 1848 NOT_PRODUCT( | |
| 1849 if (FLSVerifyIndexTable) { | |
| 1850 verifyIndexedFreeList(size); | |
| 1851 } | |
| 1852 ) | |
| 1853 } | |
| 1854 | |
| 1855 FreeChunk* CompactibleFreeListSpace::bestFitSmall(size_t numWords) { | |
| 1856 /* A hint is the next larger size that has a surplus. | |
| 1857 Start search at a size large enough to guarantee that | |
| 1858 the excess is >= MIN_CHUNK. */ | |
| 1859 size_t start = align_object_size(numWords + MinChunkSize); | |
| 1860 if (start < IndexSetSize) { | |
| 1861 FreeList* it = _indexedFreeList; | |
| 1862 size_t hint = _indexedFreeList[start].hint(); | |
| 1863 while (hint < IndexSetSize) { | |
| 1864 assert(hint % MinObjAlignment == 0, "hint should be aligned"); | |
| 1865 FreeList *fl = &_indexedFreeList[hint]; | |
| 1866 if (fl->surplus() > 0 && fl->head() != NULL) { | |
| 1867 // Found a list with surplus, reset original hint | |
| 1868 // and split out a free chunk which is returned. | |
| 1869 _indexedFreeList[start].set_hint(hint); | |
| 1870 FreeChunk* res = getFromListGreater(fl, numWords); | |
| 1871 assert(res == NULL || res->isFree(), | |
| 1872 "Should be returning a free chunk"); | |
| 1873 return res; | |
| 1874 } | |
| 1875 hint = fl->hint(); /* keep looking */ | |
| 1876 } | |
| 1877 /* None found. */ | |
| 1878 it[start].set_hint(IndexSetSize); | |
| 1879 } | |
| 1880 return NULL; | |
| 1881 } | |
| 1882 | |
| 1883 /* Requires fl->size >= numWords + MinChunkSize */ | |
| 1884 FreeChunk* CompactibleFreeListSpace::getFromListGreater(FreeList* fl, | |
| 1885 size_t numWords) { | |
| 1886 FreeChunk *curr = fl->head(); | |
| 1887 size_t oldNumWords = curr->size(); | |
| 1888 assert(numWords >= MinChunkSize, "Word size is too small"); | |
| 1889 assert(curr != NULL, "List is empty"); | |
| 1890 assert(oldNumWords >= numWords + MinChunkSize, | |
| 1891 "Size of chunks in the list is too small"); | |
| 1892 | |
| 1893 fl->removeChunk(curr); | |
| 1894 // recorded indirectly by splitChunkAndReturnRemainder - | |
| 1895 // smallSplit(oldNumWords, numWords); | |
| 1896 FreeChunk* new_chunk = splitChunkAndReturnRemainder(curr, numWords); | |
| 1897 // Does anything have to be done for the remainder in terms of | |
| 1898 // fixing the card table? | |
| 1899 assert(new_chunk == NULL || new_chunk->isFree(), | |
| 1900 "Should be returning a free chunk"); | |
| 1901 return new_chunk; | |
| 1902 } | |
| 1903 | |
| 1904 FreeChunk* | |
| 1905 CompactibleFreeListSpace::splitChunkAndReturnRemainder(FreeChunk* chunk, | |
| 1906 size_t new_size) { | |
| 1907 assert_locked(); | |
| 1908 size_t size = chunk->size(); | |
| 1909 assert(size > new_size, "Split from a smaller block?"); | |
| 1910 assert(is_aligned(chunk), "alignment problem"); | |
| 1911 assert(size == adjustObjectSize(size), "alignment problem"); | |
| 1912 size_t rem_size = size - new_size; | |
| 1913 assert(rem_size == adjustObjectSize(rem_size), "alignment problem"); | |
| 1914 assert(rem_size >= MinChunkSize, "Free chunk smaller than minimum"); | |
| 1915 FreeChunk* ffc = (FreeChunk*)((HeapWord*)chunk + new_size); | |
| 1916 assert(is_aligned(ffc), "alignment problem"); | |
| 1917 ffc->setSize(rem_size); | |
| 1918 ffc->linkNext(NULL); | |
| 1919 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. | |
| 1920 // Above must occur before BOT is updated below. | |
| 1921 // adjust block offset table | |
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1922 OrderAccess::storestore(); |
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1923 assert(chunk->isFree() && ffc->isFree(), "Error"); |
| 0 | 1924 _bt.split_block((HeapWord*)chunk, chunk->size(), new_size); |
| 1925 if (rem_size < SmallForDictionary) { | |
| 1926 bool is_par = (SharedHeap::heap()->n_par_threads() > 0); | |
| 1927 if (is_par) _indexedFreeListParLocks[rem_size]->lock(); | |
| 1928 returnChunkToFreeList(ffc); | |
| 1929 split(size, rem_size); | |
| 1930 if (is_par) _indexedFreeListParLocks[rem_size]->unlock(); | |
| 1931 } else { | |
| 1932 returnChunkToDictionary(ffc); | |
| 1933 split(size ,rem_size); | |
| 1934 } | |
| 1935 chunk->setSize(new_size); | |
| 1936 return chunk; | |
| 1937 } | |
| 1938 | |
| 1939 void | |
| 1940 CompactibleFreeListSpace::sweep_completed() { | |
| 1941 // Now that space is probably plentiful, refill linear | |
| 1942 // allocation blocks as needed. | |
| 1943 refillLinearAllocBlocksIfNeeded(); | |
| 1944 } | |
| 1945 | |
| 1946 void | |
| 1947 CompactibleFreeListSpace::gc_prologue() { | |
| 1948 assert_locked(); | |
| 1949 if (PrintFLSStatistics != 0) { | |
| 1950 gclog_or_tty->print("Before GC:\n"); | |
| 1951 reportFreeListStatistics(); | |
| 1952 } | |
| 1953 refillLinearAllocBlocksIfNeeded(); | |
| 1954 } | |
| 1955 | |
| 1956 void | |
| 1957 CompactibleFreeListSpace::gc_epilogue() { | |
| 1958 assert_locked(); | |
| 1959 if (PrintGCDetails && Verbose && !_adaptive_freelists) { | |
| 1960 if (_smallLinearAllocBlock._word_size == 0) | |
| 1961 warning("CompactibleFreeListSpace(epilogue):: Linear allocation failure"); | |
| 1962 } | |
| 1963 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); | |
| 1964 _promoInfo.stopTrackingPromotions(); | |
| 1965 repairLinearAllocationBlocks(); | |
| 1966 // Print Space's stats | |
| 1967 if (PrintFLSStatistics != 0) { | |
| 1968 gclog_or_tty->print("After GC:\n"); | |
| 1969 reportFreeListStatistics(); | |
| 1970 } | |
| 1971 } | |
| 1972 | |
| 1973 // Iteration support, mostly delegated from a CMS generation | |
| 1974 | |
| 1975 void CompactibleFreeListSpace::save_marks() { | |
|
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1976 assert(Thread::current()->is_VM_thread(), |
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1977 "Global variable should only be set when single-threaded"); |
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1978 // Mark the "end" of the used space at the time of this call; |
| 0 | 1979 // note, however, that promoted objects from this point |
| 1980 // on are tracked in the _promoInfo below. | |
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1981 set_saved_mark_word(unallocated_block()); |
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1982 #ifdef ASSERT |
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1983 // Check the sanity of save_marks() etc. |
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1984 MemRegion ur = used_region(); |
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1985 MemRegion urasm = used_region_at_save_marks(); |
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1986 assert(ur.contains(urasm), |
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1987 err_msg(" Error at save_marks(): [" PTR_FORMAT "," PTR_FORMAT ")" |
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1988 " should contain [" PTR_FORMAT "," PTR_FORMAT ")", |
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1989 ur.start(), ur.end(), urasm.start(), urasm.end())); |
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1990 #endif |
| 0 | 1991 // inform allocator that promotions should be tracked. |
| 1992 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); | |
| 1993 _promoInfo.startTrackingPromotions(); | |
| 1994 } | |
| 1995 | |
| 1996 bool CompactibleFreeListSpace::no_allocs_since_save_marks() { | |
| 1997 assert(_promoInfo.tracking(), "No preceding save_marks?"); | |
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1998 assert(SharedHeap::heap()->n_par_threads() == 0, |
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1999 "Shouldn't be called if using parallel gc."); |
| 0 | 2000 return _promoInfo.noPromotions(); |
| 2001 } | |
| 2002 | |
| 2003 #define CFLS_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ | |
| 2004 \ | |
| 2005 void CompactibleFreeListSpace:: \ | |
| 2006 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ | |
| 2007 assert(SharedHeap::heap()->n_par_threads() == 0, \ | |
| 2008 "Shouldn't be called (yet) during parallel part of gc."); \ | |
| 2009 _promoInfo.promoted_oops_iterate##nv_suffix(blk); \ | |
| 2010 /* \ | |
| 2011 * This also restores any displaced headers and removes the elements from \ | |
| 2012 * the iteration set as they are processed, so that we have a clean slate \ | |
| 2013 * at the end of the iteration. Note, thus, that if new objects are \ | |
| 2014 * promoted as a result of the iteration they are iterated over as well. \ | |
| 2015 */ \ | |
| 2016 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); \ | |
| 2017 } | |
| 2018 | |
| 2019 ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DEFN) | |
| 2020 | |
| 2021 | |
| 2022 void CompactibleFreeListSpace::object_iterate_since_last_GC(ObjectClosure* cl) { | |
| 2023 // ugghh... how would one do this efficiently for a non-contiguous space? | |
| 2024 guarantee(false, "NYI"); | |
| 2025 } | |
| 2026 | |
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2027 bool CompactibleFreeListSpace::linearAllocationWouldFail() const { |
| 0 | 2028 return _smallLinearAllocBlock._word_size == 0; |
| 2029 } | |
| 2030 | |
| 2031 void CompactibleFreeListSpace::repairLinearAllocationBlocks() { | |
| 2032 // Fix up linear allocation blocks to look like free blocks | |
| 2033 repairLinearAllocBlock(&_smallLinearAllocBlock); | |
| 2034 } | |
| 2035 | |
| 2036 void CompactibleFreeListSpace::repairLinearAllocBlock(LinearAllocBlock* blk) { | |
| 2037 assert_locked(); | |
| 2038 if (blk->_ptr != NULL) { | |
| 2039 assert(blk->_word_size != 0 && blk->_word_size >= MinChunkSize, | |
| 2040 "Minimum block size requirement"); | |
| 2041 FreeChunk* fc = (FreeChunk*)(blk->_ptr); | |
| 2042 fc->setSize(blk->_word_size); | |
| 2043 fc->linkPrev(NULL); // mark as free | |
| 2044 fc->dontCoalesce(); | |
| 2045 assert(fc->isFree(), "just marked it free"); | |
| 2046 assert(fc->cantCoalesce(), "just marked it uncoalescable"); | |
| 2047 } | |
| 2048 } | |
| 2049 | |
| 2050 void CompactibleFreeListSpace::refillLinearAllocBlocksIfNeeded() { | |
| 2051 assert_locked(); | |
| 2052 if (_smallLinearAllocBlock._ptr == NULL) { | |
| 2053 assert(_smallLinearAllocBlock._word_size == 0, | |
| 2054 "Size of linAB should be zero if the ptr is NULL"); | |
| 2055 // Reset the linAB refill and allocation size limit. | |
| 2056 _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, SmallForLinearAlloc); | |
| 2057 } | |
| 2058 refillLinearAllocBlockIfNeeded(&_smallLinearAllocBlock); | |
| 2059 } | |
| 2060 | |
| 2061 void | |
| 2062 CompactibleFreeListSpace::refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk) { | |
| 2063 assert_locked(); | |
| 2064 assert((blk->_ptr == NULL && blk->_word_size == 0) || | |
| 2065 (blk->_ptr != NULL && blk->_word_size >= MinChunkSize), | |
| 2066 "blk invariant"); | |
| 2067 if (blk->_ptr == NULL) { | |
| 2068 refillLinearAllocBlock(blk); | |
| 2069 } | |
| 2070 if (PrintMiscellaneous && Verbose) { | |
| 2071 if (blk->_word_size == 0) { | |
| 2072 warning("CompactibleFreeListSpace(prologue):: Linear allocation failure"); | |
| 2073 } | |
| 2074 } | |
| 2075 } | |
| 2076 | |
| 2077 void | |
| 2078 CompactibleFreeListSpace::refillLinearAllocBlock(LinearAllocBlock* blk) { | |
| 2079 assert_locked(); | |
| 2080 assert(blk->_word_size == 0 && blk->_ptr == NULL, | |
| 2081 "linear allocation block should be empty"); | |
| 2082 FreeChunk* fc; | |
| 2083 if (blk->_refillSize < SmallForDictionary && | |
| 2084 (fc = getChunkFromIndexedFreeList(blk->_refillSize)) != NULL) { | |
| 2085 // A linAB's strategy might be to use small sizes to reduce | |
| 2086 // fragmentation but still get the benefits of allocation from a | |
| 2087 // linAB. | |
| 2088 } else { | |
| 2089 fc = getChunkFromDictionary(blk->_refillSize); | |
| 2090 } | |
| 2091 if (fc != NULL) { | |
| 2092 blk->_ptr = (HeapWord*)fc; | |
| 2093 blk->_word_size = fc->size(); | |
| 2094 fc->dontCoalesce(); // to prevent sweeper from sweeping us up | |
| 2095 } | |
| 2096 } | |
| 2097 | |
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2098 // Support for concurrent collection policy decisions. |
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2099 bool CompactibleFreeListSpace::should_concurrent_collect() const { |
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2100 // In the future we might want to add in frgamentation stats -- |
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2101 // including erosion of the "mountain" into this decision as well. |
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2102 return !adaptive_freelists() && linearAllocationWouldFail(); |
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2103 } |
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2104 |
| 0 | 2105 // Support for compaction |
| 2106 | |
| 2107 void CompactibleFreeListSpace::prepare_for_compaction(CompactPoint* cp) { | |
| 2108 SCAN_AND_FORWARD(cp,end,block_is_obj,block_size); | |
| 2109 // prepare_for_compaction() uses the space between live objects | |
| 2110 // so that later phase can skip dead space quickly. So verification | |
| 2111 // of the free lists doesn't work after. | |
| 2112 } | |
| 2113 | |
| 2114 #define obj_size(q) adjustObjectSize(oop(q)->size()) | |
| 2115 #define adjust_obj_size(s) adjustObjectSize(s) | |
| 2116 | |
| 2117 void CompactibleFreeListSpace::adjust_pointers() { | |
| 2118 // In other versions of adjust_pointers(), a bail out | |
| 2119 // based on the amount of live data in the generation | |
| 2120 // (i.e., if 0, bail out) may be used. | |
| 2121 // Cannot test used() == 0 here because the free lists have already | |
| 2122 // been mangled by the compaction. | |
| 2123 | |
| 2124 SCAN_AND_ADJUST_POINTERS(adjust_obj_size); | |
| 2125 // See note about verification in prepare_for_compaction(). | |
| 2126 } | |
| 2127 | |
| 2128 void CompactibleFreeListSpace::compact() { | |
| 2129 SCAN_AND_COMPACT(obj_size); | |
| 2130 } | |
| 2131 | |
| 2132 // fragmentation_metric = 1 - [sum of (fbs**2) / (sum of fbs)**2] | |
| 2133 // where fbs is free block sizes | |
| 2134 double CompactibleFreeListSpace::flsFrag() const { | |
| 2135 size_t itabFree = totalSizeInIndexedFreeLists(); | |
| 2136 double frag = 0.0; | |
| 2137 size_t i; | |
| 2138 | |
| 2139 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2140 double sz = i; | |
| 2141 frag += _indexedFreeList[i].count() * (sz * sz); | |
| 2142 } | |
| 2143 | |
| 2144 double totFree = itabFree + | |
| 2145 _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())); | |
| 2146 if (totFree > 0) { | |
| 2147 frag = ((frag + _dictionary->sum_of_squared_block_sizes()) / | |
| 2148 (totFree * totFree)); | |
| 2149 frag = (double)1.0 - frag; | |
| 2150 } else { | |
| 2151 assert(frag == 0.0, "Follows from totFree == 0"); | |
| 2152 } | |
| 2153 return frag; | |
| 2154 } | |
| 2155 | |
| 2156 void CompactibleFreeListSpace::beginSweepFLCensus( | |
| 2157 float inter_sweep_current, | |
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2158 float inter_sweep_estimate, |
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2159 float intra_sweep_estimate) { |
| 0 | 2160 assert_locked(); |
| 2161 size_t i; | |
| 2162 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2163 FreeList* fl = &_indexedFreeList[i]; | |
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2164 if (PrintFLSStatistics > 1) { |
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2165 gclog_or_tty->print("size[%d] : ", i); |
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2166 } |
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2167 fl->compute_desired(inter_sweep_current, inter_sweep_estimate, intra_sweep_estimate); |
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2168 fl->set_coalDesired((ssize_t)((double)fl->desired() * CMSSmallCoalSurplusPercent)); |
| 0 | 2169 fl->set_beforeSweep(fl->count()); |
| 2170 fl->set_bfrSurp(fl->surplus()); | |
| 2171 } | |
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2172 _dictionary->beginSweepDictCensus(CMSLargeCoalSurplusPercent, |
| 0 | 2173 inter_sweep_current, |
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2174 inter_sweep_estimate, |
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2175 intra_sweep_estimate); |
| 0 | 2176 } |
| 2177 | |
| 2178 void CompactibleFreeListSpace::setFLSurplus() { | |
| 2179 assert_locked(); | |
| 2180 size_t i; | |
| 2181 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2182 FreeList *fl = &_indexedFreeList[i]; | |
| 2183 fl->set_surplus(fl->count() - | |
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2184 (ssize_t)((double)fl->desired() * CMSSmallSplitSurplusPercent)); |
| 0 | 2185 } |
| 2186 } | |
| 2187 | |
| 2188 void CompactibleFreeListSpace::setFLHints() { | |
| 2189 assert_locked(); | |
| 2190 size_t i; | |
| 2191 size_t h = IndexSetSize; | |
| 2192 for (i = IndexSetSize - 1; i != 0; i -= IndexSetStride) { | |
| 2193 FreeList *fl = &_indexedFreeList[i]; | |
| 2194 fl->set_hint(h); | |
| 2195 if (fl->surplus() > 0) { | |
| 2196 h = i; | |
| 2197 } | |
| 2198 } | |
| 2199 } | |
| 2200 | |
| 2201 void CompactibleFreeListSpace::clearFLCensus() { | |
| 2202 assert_locked(); | |
| 2203 int i; | |
| 2204 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2205 FreeList *fl = &_indexedFreeList[i]; | |
| 2206 fl->set_prevSweep(fl->count()); | |
| 2207 fl->set_coalBirths(0); | |
| 2208 fl->set_coalDeaths(0); | |
| 2209 fl->set_splitBirths(0); | |
| 2210 fl->set_splitDeaths(0); | |
| 2211 } | |
| 2212 } | |
| 2213 | |
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2214 void CompactibleFreeListSpace::endSweepFLCensus(size_t sweep_count) { |
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2215 if (PrintFLSStatistics > 0) { |
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2216 HeapWord* largestAddr = (HeapWord*) dictionary()->findLargestDict(); |
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2217 gclog_or_tty->print_cr("CMS: Large block " PTR_FORMAT, |
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2218 largestAddr); |
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2219 } |
| 0 | 2220 setFLSurplus(); |
| 2221 setFLHints(); | |
| 2222 if (PrintGC && PrintFLSCensus > 0) { | |
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2223 printFLCensus(sweep_count); |
| 0 | 2224 } |
| 2225 clearFLCensus(); | |
| 2226 assert_locked(); | |
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2227 _dictionary->endSweepDictCensus(CMSLargeSplitSurplusPercent); |
| 0 | 2228 } |
| 2229 | |
| 2230 bool CompactibleFreeListSpace::coalOverPopulated(size_t size) { | |
| 2231 if (size < SmallForDictionary) { | |
| 2232 FreeList *fl = &_indexedFreeList[size]; | |
| 2233 return (fl->coalDesired() < 0) || | |
| 2234 ((int)fl->count() > fl->coalDesired()); | |
| 2235 } else { | |
| 2236 return dictionary()->coalDictOverPopulated(size); | |
| 2237 } | |
| 2238 } | |
| 2239 | |
| 2240 void CompactibleFreeListSpace::smallCoalBirth(size_t size) { | |
| 2241 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2242 FreeList *fl = &_indexedFreeList[size]; | |
| 2243 fl->increment_coalBirths(); | |
| 2244 fl->increment_surplus(); | |
| 2245 } | |
| 2246 | |
| 2247 void CompactibleFreeListSpace::smallCoalDeath(size_t size) { | |
| 2248 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2249 FreeList *fl = &_indexedFreeList[size]; | |
| 2250 fl->increment_coalDeaths(); | |
| 2251 fl->decrement_surplus(); | |
| 2252 } | |
| 2253 | |
| 2254 void CompactibleFreeListSpace::coalBirth(size_t size) { | |
| 2255 if (size < SmallForDictionary) { | |
| 2256 smallCoalBirth(size); | |
| 2257 } else { | |
| 2258 dictionary()->dictCensusUpdate(size, | |
| 2259 false /* split */, | |
| 2260 true /* birth */); | |
| 2261 } | |
| 2262 } | |
| 2263 | |
| 2264 void CompactibleFreeListSpace::coalDeath(size_t size) { | |
| 2265 if(size < SmallForDictionary) { | |
| 2266 smallCoalDeath(size); | |
| 2267 } else { | |
| 2268 dictionary()->dictCensusUpdate(size, | |
| 2269 false /* split */, | |
| 2270 false /* birth */); | |
| 2271 } | |
| 2272 } | |
| 2273 | |
| 2274 void CompactibleFreeListSpace::smallSplitBirth(size_t size) { | |
| 2275 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2276 FreeList *fl = &_indexedFreeList[size]; | |
| 2277 fl->increment_splitBirths(); | |
| 2278 fl->increment_surplus(); | |
| 2279 } | |
| 2280 | |
| 2281 void CompactibleFreeListSpace::smallSplitDeath(size_t size) { | |
| 2282 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2283 FreeList *fl = &_indexedFreeList[size]; | |
| 2284 fl->increment_splitDeaths(); | |
| 2285 fl->decrement_surplus(); | |
| 2286 } | |
| 2287 | |
| 2288 void CompactibleFreeListSpace::splitBirth(size_t size) { | |
| 2289 if (size < SmallForDictionary) { | |
| 2290 smallSplitBirth(size); | |
| 2291 } else { | |
| 2292 dictionary()->dictCensusUpdate(size, | |
| 2293 true /* split */, | |
| 2294 true /* birth */); | |
| 2295 } | |
| 2296 } | |
| 2297 | |
| 2298 void CompactibleFreeListSpace::splitDeath(size_t size) { | |
| 2299 if (size < SmallForDictionary) { | |
| 2300 smallSplitDeath(size); | |
| 2301 } else { | |
| 2302 dictionary()->dictCensusUpdate(size, | |
| 2303 true /* split */, | |
| 2304 false /* birth */); | |
| 2305 } | |
| 2306 } | |
| 2307 | |
| 2308 void CompactibleFreeListSpace::split(size_t from, size_t to1) { | |
| 2309 size_t to2 = from - to1; | |
| 2310 splitDeath(from); | |
| 2311 splitBirth(to1); | |
| 2312 splitBirth(to2); | |
| 2313 } | |
| 2314 | |
| 2315 void CompactibleFreeListSpace::print() const { | |
|
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2316 print_on(tty); |
| 0 | 2317 } |
| 2318 | |
| 2319 void CompactibleFreeListSpace::prepare_for_verify() { | |
| 2320 assert_locked(); | |
| 2321 repairLinearAllocationBlocks(); | |
| 2322 // Verify that the SpoolBlocks look like free blocks of | |
| 2323 // appropriate sizes... To be done ... | |
| 2324 } | |
| 2325 | |
| 2326 class VerifyAllBlksClosure: public BlkClosure { | |
|
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2327 private: |
| 0 | 2328 const CompactibleFreeListSpace* _sp; |
| 2329 const MemRegion _span; | |
|
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2330 HeapWord* _last_addr; |
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2331 size_t _last_size; |
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2332 bool _last_was_obj; |
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2333 bool _last_was_live; |
| 0 | 2334 |
| 2335 public: | |
| 2336 VerifyAllBlksClosure(const CompactibleFreeListSpace* sp, | |
|
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2337 MemRegion span) : _sp(sp), _span(span), |
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2338 _last_addr(NULL), _last_size(0), |
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2339 _last_was_obj(false), _last_was_live(false) { } |
| 0 | 2340 |
|
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2341 virtual size_t do_blk(HeapWord* addr) { |
| 0 | 2342 size_t res; |
|
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2343 bool was_obj = false; |
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2344 bool was_live = false; |
| 0 | 2345 if (_sp->block_is_obj(addr)) { |
|
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2346 was_obj = true; |
| 0 | 2347 oop p = oop(addr); |
| 2348 guarantee(p->is_oop(), "Should be an oop"); | |
| 2349 res = _sp->adjustObjectSize(p->size()); | |
| 2350 if (_sp->obj_is_alive(addr)) { | |
|
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2351 was_live = true; |
| 0 | 2352 p->verify(); |
| 2353 } | |
| 2354 } else { | |
| 2355 FreeChunk* fc = (FreeChunk*)addr; | |
| 2356 res = fc->size(); | |
| 2357 if (FLSVerifyLists && !fc->cantCoalesce()) { | |
| 2358 guarantee(_sp->verifyChunkInFreeLists(fc), | |
| 2359 "Chunk should be on a free list"); | |
| 2360 } | |
| 2361 } | |
|
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2362 if (res == 0) { |
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2363 gclog_or_tty->print_cr("Livelock: no rank reduction!"); |
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2364 gclog_or_tty->print_cr( |
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2365 " Current: addr = " PTR_FORMAT ", size = " SIZE_FORMAT ", obj = %s, live = %s \n" |
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2366 " Previous: addr = " PTR_FORMAT ", size = " SIZE_FORMAT ", obj = %s, live = %s \n", |
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2367 addr, res, was_obj ?"true":"false", was_live ?"true":"false", |
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2368 _last_addr, _last_size, _last_was_obj?"true":"false", _last_was_live?"true":"false"); |
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2369 _sp->print_on(gclog_or_tty); |
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2370 guarantee(false, "Seppuku!"); |
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2371 } |
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2372 _last_addr = addr; |
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2373 _last_size = res; |
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2374 _last_was_obj = was_obj; |
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2375 _last_was_live = was_live; |
| 0 | 2376 return res; |
| 2377 } | |
| 2378 }; | |
| 2379 | |
| 2380 class VerifyAllOopsClosure: public OopClosure { | |
|
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2381 private: |
| 0 | 2382 const CMSCollector* _collector; |
| 2383 const CompactibleFreeListSpace* _sp; | |
| 2384 const MemRegion _span; | |
| 2385 const bool _past_remark; | |
| 2386 const CMSBitMap* _bit_map; | |
| 2387 | |
|
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2388 protected: |
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2389 void do_oop(void* p, oop obj) { |
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2390 if (_span.contains(obj)) { // the interior oop points into CMS heap |
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2391 if (!_span.contains(p)) { // reference from outside CMS heap |
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2392 // Should be a valid object; the first disjunct below allows |
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2393 // us to sidestep an assertion in block_is_obj() that insists |
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2394 // that p be in _sp. Note that several generations (and spaces) |
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2395 // are spanned by _span (CMS heap) above. |
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2396 guarantee(!_sp->is_in_reserved(obj) || |
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2397 _sp->block_is_obj((HeapWord*)obj), |
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2398 "Should be an object"); |
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2399 guarantee(obj->is_oop(), "Should be an oop"); |
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2400 obj->verify(); |
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2401 if (_past_remark) { |
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2402 // Remark has been completed, the object should be marked |
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2403 _bit_map->isMarked((HeapWord*)obj); |
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2404 } |
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2405 } else { // reference within CMS heap |
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2406 if (_past_remark) { |
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2407 // Remark has been completed -- so the referent should have |
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2408 // been marked, if referring object is. |
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2409 if (_bit_map->isMarked(_collector->block_start(p))) { |
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2410 guarantee(_bit_map->isMarked((HeapWord*)obj), "Marking error?"); |
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2411 } |
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2412 } |
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2413 } |
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2414 } else if (_sp->is_in_reserved(p)) { |
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2415 // the reference is from FLS, and points out of FLS |
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2416 guarantee(obj->is_oop(), "Should be an oop"); |
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2417 obj->verify(); |
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2418 } |
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2419 } |
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2420 |
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2421 template <class T> void do_oop_work(T* p) { |
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2422 T heap_oop = oopDesc::load_heap_oop(p); |
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2423 if (!oopDesc::is_null(heap_oop)) { |
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2424 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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2425 do_oop(p, obj); |
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2426 } |
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2427 } |
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2428 |
| 0 | 2429 public: |
| 2430 VerifyAllOopsClosure(const CMSCollector* collector, | |
| 2431 const CompactibleFreeListSpace* sp, MemRegion span, | |
| 2432 bool past_remark, CMSBitMap* bit_map) : | |
| 2433 OopClosure(), _collector(collector), _sp(sp), _span(span), | |
| 2434 _past_remark(past_remark), _bit_map(bit_map) { } | |
| 2435 | |
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2436 virtual void do_oop(oop* p) { VerifyAllOopsClosure::do_oop_work(p); } |
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2437 virtual void do_oop(narrowOop* p) { VerifyAllOopsClosure::do_oop_work(p); } |
| 0 | 2438 }; |
| 2439 | |
| 2440 void CompactibleFreeListSpace::verify(bool ignored) const { | |
| 2441 assert_lock_strong(&_freelistLock); | |
| 2442 verify_objects_initialized(); | |
| 2443 MemRegion span = _collector->_span; | |
| 2444 bool past_remark = (_collector->abstract_state() == | |
| 2445 CMSCollector::Sweeping); | |
| 2446 | |
| 2447 ResourceMark rm; | |
| 2448 HandleMark hm; | |
| 2449 | |
| 2450 // Check integrity of CFL data structures | |
| 2451 _promoInfo.verify(); | |
| 2452 _dictionary->verify(); | |
| 2453 if (FLSVerifyIndexTable) { | |
| 2454 verifyIndexedFreeLists(); | |
| 2455 } | |
| 2456 // Check integrity of all objects and free blocks in space | |
| 2457 { | |
| 2458 VerifyAllBlksClosure cl(this, span); | |
| 2459 ((CompactibleFreeListSpace*)this)->blk_iterate(&cl); // cast off const | |
| 2460 } | |
| 2461 // Check that all references in the heap to FLS | |
| 2462 // are to valid objects in FLS or that references in | |
| 2463 // FLS are to valid objects elsewhere in the heap | |
| 2464 if (FLSVerifyAllHeapReferences) | |
| 2465 { | |
| 2466 VerifyAllOopsClosure cl(_collector, this, span, past_remark, | |
| 2467 _collector->markBitMap()); | |
| 2468 CollectedHeap* ch = Universe::heap(); | |
| 2469 ch->oop_iterate(&cl); // all oops in generations | |
| 2470 ch->permanent_oop_iterate(&cl); // all oops in perm gen | |
| 2471 } | |
| 2472 | |
| 2473 if (VerifyObjectStartArray) { | |
| 2474 // Verify the block offset table | |
| 2475 _bt.verify(); | |
| 2476 } | |
| 2477 } | |
| 2478 | |
| 2479 #ifndef PRODUCT | |
| 2480 void CompactibleFreeListSpace::verifyFreeLists() const { | |
| 2481 if (FLSVerifyLists) { | |
| 2482 _dictionary->verify(); | |
| 2483 verifyIndexedFreeLists(); | |
| 2484 } else { | |
| 2485 if (FLSVerifyDictionary) { | |
| 2486 _dictionary->verify(); | |
| 2487 } | |
| 2488 if (FLSVerifyIndexTable) { | |
| 2489 verifyIndexedFreeLists(); | |
| 2490 } | |
| 2491 } | |
| 2492 } | |
| 2493 #endif | |
| 2494 | |
| 2495 void CompactibleFreeListSpace::verifyIndexedFreeLists() const { | |
| 2496 size_t i = 0; | |
| 2497 for (; i < MinChunkSize; i++) { | |
| 2498 guarantee(_indexedFreeList[i].head() == NULL, "should be NULL"); | |
| 2499 } | |
| 2500 for (; i < IndexSetSize; i++) { | |
| 2501 verifyIndexedFreeList(i); | |
| 2502 } | |
| 2503 } | |
| 2504 | |
| 2505 void CompactibleFreeListSpace::verifyIndexedFreeList(size_t size) const { | |
|
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2506 FreeChunk* fc = _indexedFreeList[size].head(); |
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2507 FreeChunk* tail = _indexedFreeList[size].tail(); |
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2508 size_t num = _indexedFreeList[size].count(); |
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2509 size_t n = 0; |
|
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2510 guarantee(((size >= MinChunkSize) && (size % IndexSetStride == 0)) || fc == NULL, |
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2511 "Slot should have been empty"); |
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2512 for (; fc != NULL; fc = fc->next(), n++) { |
| 0 | 2513 guarantee(fc->size() == size, "Size inconsistency"); |
| 2514 guarantee(fc->isFree(), "!free?"); | |
| 2515 guarantee(fc->next() == NULL || fc->next()->prev() == fc, "Broken list"); | |
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2516 guarantee((fc->next() == NULL) == (fc == tail), "Incorrect tail"); |
| 0 | 2517 } |
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2518 guarantee(n == num, "Incorrect count"); |
| 0 | 2519 } |
| 2520 | |
| 2521 #ifndef PRODUCT | |
|
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2522 void CompactibleFreeListSpace::check_free_list_consistency() const { |
| 0 | 2523 assert(_dictionary->minSize() <= IndexSetSize, |
| 2524 "Some sizes can't be allocated without recourse to" | |
| 2525 " linear allocation buffers"); | |
| 2526 assert(MIN_TREE_CHUNK_SIZE*HeapWordSize == sizeof(TreeChunk), | |
| 2527 "else MIN_TREE_CHUNK_SIZE is wrong"); | |
|
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2528 assert((IndexSetStride == 2 && IndexSetStart == 4) || // 32-bit |
|
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|
2529 (IndexSetStride == 1 && IndexSetStart == 3), "just checking"); // 64-bit |
| 0 | 2530 assert((IndexSetStride != 2) || (MinChunkSize % 2 == 0), |
| 2531 "Some for-loops may be incorrectly initialized"); | |
| 2532 assert((IndexSetStride != 2) || (IndexSetSize % 2 == 1), | |
| 2533 "For-loops that iterate over IndexSet with stride 2 may be wrong"); | |
| 2534 } | |
| 2535 #endif | |
| 2536 | |
|
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|
2537 void CompactibleFreeListSpace::printFLCensus(size_t sweep_count) const { |
| 0 | 2538 assert_lock_strong(&_freelistLock); |
|
12
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|
2539 FreeList total; |
|
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|
2540 gclog_or_tty->print("end sweep# " SIZE_FORMAT "\n", sweep_count); |
|
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|
2541 FreeList::print_labels_on(gclog_or_tty, "size"); |
| 0 | 2542 size_t totalFree = 0; |
| 2543 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2544 const FreeList *fl = &_indexedFreeList[i]; | |
|
12
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2545 totalFree += fl->count() * fl->size(); |
|
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|
2546 if (i % (40*IndexSetStride) == 0) { |
|
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|
2547 FreeList::print_labels_on(gclog_or_tty, "size"); |
|
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|
2548 } |
|
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|
2549 fl->print_on(gclog_or_tty); |
|
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|
2550 total.set_bfrSurp( total.bfrSurp() + fl->bfrSurp() ); |
|
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|
2551 total.set_surplus( total.surplus() + fl->surplus() ); |
|
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2552 total.set_desired( total.desired() + fl->desired() ); |
|
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2553 total.set_prevSweep( total.prevSweep() + fl->prevSweep() ); |
|
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2554 total.set_beforeSweep(total.beforeSweep() + fl->beforeSweep()); |
|
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2555 total.set_count( total.count() + fl->count() ); |
|
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|
2556 total.set_coalBirths( total.coalBirths() + fl->coalBirths() ); |
|
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|
2557 total.set_coalDeaths( total.coalDeaths() + fl->coalDeaths() ); |
|
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|
2558 total.set_splitBirths(total.splitBirths() + fl->splitBirths()); |
|
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2559 total.set_splitDeaths(total.splitDeaths() + fl->splitDeaths()); |
| 0 | 2560 } |
|
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|
2561 total.print_on(gclog_or_tty, "TOTAL"); |
|
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|
2562 gclog_or_tty->print_cr("Total free in indexed lists " |
|
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|
2563 SIZE_FORMAT " words", totalFree); |
| 0 | 2564 gclog_or_tty->print("growth: %8.5f deficit: %8.5f\n", |
|
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|
2565 (double)(total.splitBirths()+total.coalBirths()-total.splitDeaths()-total.coalDeaths())/ |
|
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|
2566 (total.prevSweep() != 0 ? (double)total.prevSweep() : 1.0), |
|
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|
2567 (double)(total.desired() - total.count())/(total.desired() != 0 ? (double)total.desired() : 1.0)); |
| 0 | 2568 _dictionary->printDictCensus(); |
| 2569 } | |
| 2570 | |
|
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|
2571 /////////////////////////////////////////////////////////////////////////// |
|
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|
2572 // CFLS_LAB |
|
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|
2573 /////////////////////////////////////////////////////////////////////////// |
|
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|
2574 |
|
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|
2575 #define VECTOR_257(x) \ |
|
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|
2576 /* 1 2 3 4 5 6 7 8 9 1x 11 12 13 14 15 16 17 18 19 2x 21 22 23 24 25 26 27 28 29 3x 31 32 */ \ |
|
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2577 { x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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|
2578 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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2579 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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|
2580 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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|
2581 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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2582 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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2583 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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2584 x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, \ |
|
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|
2585 x } |
|
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|
2586 |
|
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|
2587 // Initialize with default setting of CMSParPromoteBlocksToClaim, _not_ |
|
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|
2588 // OldPLABSize, whose static default is different; if overridden at the |
|
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|
2589 // command-line, this will get reinitialized via a call to |
|
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|
2590 // modify_initialization() below. |
|
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|
2591 AdaptiveWeightedAverage CFLS_LAB::_blocks_to_claim[] = |
|
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|
2592 VECTOR_257(AdaptiveWeightedAverage(OldPLABWeight, (float)CMSParPromoteBlocksToClaim)); |
|
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|
2593 size_t CFLS_LAB::_global_num_blocks[] = VECTOR_257(0); |
|
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|
2594 int CFLS_LAB::_global_num_workers[] = VECTOR_257(0); |
| 0 | 2595 |
| 2596 CFLS_LAB::CFLS_LAB(CompactibleFreeListSpace* cfls) : | |
| 2597 _cfls(cfls) | |
| 2598 { | |
|
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|
2599 assert(CompactibleFreeListSpace::IndexSetSize == 257, "Modify VECTOR_257() macro above"); |
| 0 | 2600 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
| 2601 i < CompactibleFreeListSpace::IndexSetSize; | |
| 2602 i += CompactibleFreeListSpace::IndexSetStride) { | |
| 2603 _indexedFreeList[i].set_size(i); | |
|
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|
2604 _num_blocks[i] = 0; |
|
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|
2605 } |
|
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|
2606 } |
|
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|
2607 |
|
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|
2608 static bool _CFLS_LAB_modified = false; |
|
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|
2609 |
|
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|
2610 void CFLS_LAB::modify_initialization(size_t n, unsigned wt) { |
|
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|
2611 assert(!_CFLS_LAB_modified, "Call only once"); |
|
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|
2612 _CFLS_LAB_modified = true; |
|
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|
2613 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
|
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|
2614 i < CompactibleFreeListSpace::IndexSetSize; |
|
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|
2615 i += CompactibleFreeListSpace::IndexSetStride) { |
|
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|
2616 _blocks_to_claim[i].modify(n, wt, true /* force */); |
| 0 | 2617 } |
| 2618 } | |
| 2619 | |
| 2620 HeapWord* CFLS_LAB::alloc(size_t word_sz) { | |
| 2621 FreeChunk* res; | |
|
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|
2622 assert(word_sz == _cfls->adjustObjectSize(word_sz), "Error"); |
| 0 | 2623 if (word_sz >= CompactibleFreeListSpace::IndexSetSize) { |
| 2624 // This locking manages sync with other large object allocations. | |
| 2625 MutexLockerEx x(_cfls->parDictionaryAllocLock(), | |
| 2626 Mutex::_no_safepoint_check_flag); | |
| 2627 res = _cfls->getChunkFromDictionaryExact(word_sz); | |
| 2628 if (res == NULL) return NULL; | |
| 2629 } else { | |
| 2630 FreeList* fl = &_indexedFreeList[word_sz]; | |
| 2631 if (fl->count() == 0) { | |
| 2632 // Attempt to refill this local free list. | |
|
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|
2633 get_from_global_pool(word_sz, fl); |
| 0 | 2634 // If it didn't work, give up. |
| 2635 if (fl->count() == 0) return NULL; | |
| 2636 } | |
| 2637 res = fl->getChunkAtHead(); | |
| 2638 assert(res != NULL, "Why was count non-zero?"); | |
| 2639 } | |
| 2640 res->markNotFree(); | |
| 2641 assert(!res->isFree(), "shouldn't be marked free"); | |
| 187 | 2642 assert(oop(res)->klass_or_null() == NULL, "should look uninitialized"); |
| 0 | 2643 // mangle a just allocated object with a distinct pattern. |
| 2644 debug_only(res->mangleAllocated(word_sz)); | |
| 2645 return (HeapWord*)res; | |
| 2646 } | |
| 2647 | |
|
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|
2648 // Get a chunk of blocks of the right size and update related |
|
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|
2649 // book-keeping stats |
|
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|
2650 void CFLS_LAB::get_from_global_pool(size_t word_sz, FreeList* fl) { |
|
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|
2651 // Get the #blocks we want to claim |
|
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|
2652 size_t n_blks = (size_t)_blocks_to_claim[word_sz].average(); |
|
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|
2653 assert(n_blks > 0, "Error"); |
|
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|
2654 assert(ResizePLAB || n_blks == OldPLABSize, "Error"); |
|
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|
2655 // In some cases, when the application has a phase change, |
|
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|
2656 // there may be a sudden and sharp shift in the object survival |
|
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|
2657 // profile, and updating the counts at the end of a scavenge |
|
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|
2658 // may not be quick enough, giving rise to large scavenge pauses |
|
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|
2659 // during these phase changes. It is beneficial to detect such |
|
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|
2660 // changes on-the-fly during a scavenge and avoid such a phase-change |
|
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|
2661 // pothole. The following code is a heuristic attempt to do that. |
|
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|
2662 // It is protected by a product flag until we have gained |
|
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|
2663 // enough experience with this heuristic and fine-tuned its behaviour. |
|
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|
2664 // WARNING: This might increase fragmentation if we overreact to |
|
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|
2665 // small spikes, so some kind of historical smoothing based on |
|
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|
2666 // previous experience with the greater reactivity might be useful. |
|
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|
2667 // Lacking sufficient experience, CMSOldPLABResizeQuicker is disabled by |
|
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|
2668 // default. |
|
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|
2669 if (ResizeOldPLAB && CMSOldPLABResizeQuicker) { |
|
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|
2670 size_t multiple = _num_blocks[word_sz]/(CMSOldPLABToleranceFactor*CMSOldPLABNumRefills*n_blks); |
|
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|
2671 n_blks += CMSOldPLABReactivityFactor*multiple*n_blks; |
|
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|
2672 n_blks = MIN2(n_blks, CMSOldPLABMax); |
|
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|
2673 } |
|
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|
2674 assert(n_blks > 0, "Error"); |
|
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|
2675 _cfls->par_get_chunk_of_blocks(word_sz, n_blks, fl); |
|
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|
2676 // Update stats table entry for this block size |
|
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|
2677 _num_blocks[word_sz] += fl->count(); |
|
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|
2678 } |
|
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|
2679 |
|
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|
2680 void CFLS_LAB::compute_desired_plab_size() { |
|
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|
2681 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
| 0 | 2682 i < CompactibleFreeListSpace::IndexSetSize; |
| 2683 i += CompactibleFreeListSpace::IndexSetStride) { | |
|
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2684 assert((_global_num_workers[i] == 0) == (_global_num_blocks[i] == 0), |
|
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|
2685 "Counter inconsistency"); |
|
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|
2686 if (_global_num_workers[i] > 0) { |
|
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|
2687 // Need to smooth wrt historical average |
|
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|
2688 if (ResizeOldPLAB) { |
|
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|
2689 _blocks_to_claim[i].sample( |
|
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|
2690 MAX2((size_t)CMSOldPLABMin, |
|
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|
2691 MIN2((size_t)CMSOldPLABMax, |
|
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|
2692 _global_num_blocks[i]/(_global_num_workers[i]*CMSOldPLABNumRefills)))); |
|
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|
2693 } |
|
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|
2694 // Reset counters for next round |
|
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|
2695 _global_num_workers[i] = 0; |
|
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|
2696 _global_num_blocks[i] = 0; |
|
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|
2697 if (PrintOldPLAB) { |
|
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|
2698 gclog_or_tty->print_cr("[%d]: %d", i, (size_t)_blocks_to_claim[i].average()); |
|
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|
2699 } |
| 0 | 2700 } |
| 2701 } | |
| 2702 } | |
| 2703 | |
|
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|
2704 // If this is changed in the future to allow parallel |
|
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|
2705 // access, one would need to take the FL locks and, |
|
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|
2706 // depending on how it is used, stagger access from |
|
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|
2707 // parallel threads to reduce contention. |
|
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|
2708 void CFLS_LAB::retire(int tid) { |
|
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|
2709 // We run this single threaded with the world stopped; |
|
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|
2710 // so no need for locks and such. |
|
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|
2711 NOT_PRODUCT(Thread* t = Thread::current();) |
|
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|
2712 assert(Thread::current()->is_VM_thread(), "Error"); |
|
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|
2713 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
|
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|
2714 i < CompactibleFreeListSpace::IndexSetSize; |
|
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|
2715 i += CompactibleFreeListSpace::IndexSetStride) { |
|
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|
2716 assert(_num_blocks[i] >= (size_t)_indexedFreeList[i].count(), |
|
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|
2717 "Can't retire more than what we obtained"); |
|
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|
2718 if (_num_blocks[i] > 0) { |
|
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|
2719 size_t num_retire = _indexedFreeList[i].count(); |
|
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|
2720 assert(_num_blocks[i] > num_retire, "Should have used at least one"); |
|
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|
2721 { |
|
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|
2722 // MutexLockerEx x(_cfls->_indexedFreeListParLocks[i], |
|
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|
2723 // Mutex::_no_safepoint_check_flag); |
|
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|
2724 |
|
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|
2725 // Update globals stats for num_blocks used |
|
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|
2726 _global_num_blocks[i] += (_num_blocks[i] - num_retire); |
|
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|
2727 _global_num_workers[i]++; |
|
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|
2728 assert(_global_num_workers[i] <= (ssize_t)ParallelGCThreads, "Too big"); |
|
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|
2729 if (num_retire > 0) { |
|
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|
2730 _cfls->_indexedFreeList[i].prepend(&_indexedFreeList[i]); |
|
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|
2731 // Reset this list. |
|
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|
2732 _indexedFreeList[i] = FreeList(); |
|
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|
2733 _indexedFreeList[i].set_size(i); |
|
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|
2734 } |
|
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|
2735 } |
|
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|
2736 if (PrintOldPLAB) { |
|
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|
2737 gclog_or_tty->print_cr("%d[%d]: %d/%d/%d", |
|
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|
2738 tid, i, num_retire, _num_blocks[i], (size_t)_blocks_to_claim[i].average()); |
|
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|
2739 } |
|
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|
2740 // Reset stats for next round |
|
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|
2741 _num_blocks[i] = 0; |
|
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|
2742 } |
|
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|
2743 } |
|
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|
2744 } |
|
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|
2745 |
|
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|
2746 void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl) { |
| 0 | 2747 assert(fl->count() == 0, "Precondition."); |
| 2748 assert(word_sz < CompactibleFreeListSpace::IndexSetSize, | |
| 2749 "Precondition"); | |
| 2750 | |
|
1145
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|
2751 // We'll try all multiples of word_sz in the indexed set, starting with |
|
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|
2752 // word_sz itself and, if CMSSplitIndexedFreeListBlocks, try larger multiples, |
|
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|
2753 // then try getting a big chunk and splitting it. |
|
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diff
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|
2754 { |
|
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|
2755 bool found; |
|
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|
2756 int k; |
|
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diff
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|
2757 size_t cur_sz; |
|
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|
2758 for (k = 1, cur_sz = k * word_sz, found = false; |
|
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diff
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|
2759 (cur_sz < CompactibleFreeListSpace::IndexSetSize) && |
|
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|
2760 (CMSSplitIndexedFreeListBlocks || k <= 1); |
|
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diff
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|
2761 k++, cur_sz = k * word_sz) { |
|
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|
2762 FreeList fl_for_cur_sz; // Empty. |
|
e018e6884bd8
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diff
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|
2763 fl_for_cur_sz.set_size(cur_sz); |
|
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parents:
579
diff
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|
2764 { |
|
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|
2765 MutexLockerEx x(_indexedFreeListParLocks[cur_sz], |
|
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diff
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|
2766 Mutex::_no_safepoint_check_flag); |
|
1716
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|
2767 FreeList* gfl = &_indexedFreeList[cur_sz]; |
|
1145
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|
2768 if (gfl->count() != 0) { |
|
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diff
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|
2769 // nn is the number of chunks of size cur_sz that |
|
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diff
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|
2770 // we'd need to split k-ways each, in order to create |
|
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diff
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|
2771 // "n" chunks of size word_sz each. |
|
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diff
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|
2772 const size_t nn = MAX2(n/k, (size_t)1); |
|
e018e6884bd8
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579
diff
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|
2773 gfl->getFirstNChunksFromList(nn, &fl_for_cur_sz); |
|
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parents:
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diff
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|
2774 found = true; |
|
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diff
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|
2775 if (k > 1) { |
|
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diff
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|
2776 // Update split death stats for the cur_sz-size blocks list: |
|
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diff
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|
2777 // we increment the split death count by the number of blocks |
|
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diff
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|
2778 // we just took from the cur_sz-size blocks list and which |
|
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|
2779 // we will be splitting below. |
|
1716
be3f9c242c9d
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|
2780 ssize_t deaths = gfl->splitDeaths() + |
|
1145
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|
2781 fl_for_cur_sz.count(); |
|
1716
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|
2782 gfl->set_splitDeaths(deaths); |
|
1145
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|
2783 } |
|
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|
2784 } |
|
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|
2785 } |
|
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diff
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|
2786 // Now transfer fl_for_cur_sz to fl. Common case, we hope, is k = 1. |
|
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parents:
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|
2787 if (found) { |
|
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|
2788 if (k == 1) { |
|
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|
2789 fl->prepend(&fl_for_cur_sz); |
|
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diff
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|
2790 } else { |
|
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diff
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|
2791 // Divide each block on fl_for_cur_sz up k ways. |
|
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579
diff
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|
2792 FreeChunk* fc; |
|
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|
2793 while ((fc = fl_for_cur_sz.getChunkAtHead()) != NULL) { |
|
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diff
changeset
|
2794 // Must do this in reverse order, so that anybody attempting to |
|
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diff
changeset
|
2795 // access the main chunk sees it as a single free block until we |
|
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parents:
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diff
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|
2796 // change it. |
|
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diff
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|
2797 size_t fc_size = fc->size(); |
|
1716
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|
2798 assert(fc->isFree(), "Error"); |
|
1145
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|
2799 for (int i = k-1; i >= 0; i--) { |
|
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|
2800 FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz); |
|
1716
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|
2801 assert((i != 0) || |
|
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|
2802 ((fc == ffc) && ffc->isFree() && |
|
be3f9c242c9d
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|
2803 (ffc->size() == k*word_sz) && (fc_size == word_sz)), |
|
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|
2804 "Counting error"); |
|
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2805 ffc->setSize(word_sz); |
|
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2806 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. |
|
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2807 ffc->linkNext(NULL); |
|
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2808 // Above must occur before BOT is updated below. |
|
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2809 OrderAccess::storestore(); |
|
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2810 // splitting from the right, fc_size == i * word_sz |
|
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2811 _bt.mark_block((HeapWord*)ffc, word_sz, true /* reducing */); |
|
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2812 fc_size -= word_sz; |
|
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2813 assert(fc_size == i*word_sz, "Error"); |
|
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2814 _bt.verify_not_unallocated((HeapWord*)ffc, word_sz); |
|
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2815 _bt.verify_single_block((HeapWord*)fc, fc_size); |
|
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2816 _bt.verify_single_block((HeapWord*)ffc, word_sz); |
|
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2817 // Push this on "fl". |
|
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2818 fl->returnChunkAtHead(ffc); |
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2819 } |
|
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2820 // TRAP |
|
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2821 assert(fl->tail()->next() == NULL, "List invariant."); |
|
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2822 } |
|
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2823 } |
|
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2824 // Update birth stats for this block size. |
|
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2825 size_t num = fl->count(); |
|
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|
2826 MutexLockerEx x(_indexedFreeListParLocks[word_sz], |
|
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2827 Mutex::_no_safepoint_check_flag); |
|
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2828 ssize_t births = _indexedFreeList[word_sz].splitBirths() + num; |
|
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2829 _indexedFreeList[word_sz].set_splitBirths(births); |
|
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2830 return; |
| 0 | 2831 } |
| 2832 } | |
| 2833 } | |
| 2834 // Otherwise, we'll split a block from the dictionary. | |
| 2835 FreeChunk* fc = NULL; | |
| 2836 FreeChunk* rem_fc = NULL; | |
| 2837 size_t rem; | |
| 2838 { | |
| 2839 MutexLockerEx x(parDictionaryAllocLock(), | |
| 2840 Mutex::_no_safepoint_check_flag); | |
| 2841 while (n > 0) { | |
| 2842 fc = dictionary()->getChunk(MAX2(n * word_sz, | |
| 2843 _dictionary->minSize()), | |
| 2844 FreeBlockDictionary::atLeast); | |
| 2845 if (fc != NULL) { | |
|
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2846 _bt.allocated((HeapWord*)fc, fc->size(), true /* reducing */); // update _unallocated_blk |
| 0 | 2847 dictionary()->dictCensusUpdate(fc->size(), |
| 2848 true /*split*/, | |
| 2849 false /*birth*/); | |
| 2850 break; | |
| 2851 } else { | |
| 2852 n--; | |
| 2853 } | |
| 2854 } | |
| 2855 if (fc == NULL) return; | |
|
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2856 // Otherwise, split up that block. |
|
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2857 assert((ssize_t)n >= 1, "Control point invariant"); |
|
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2858 assert(fc->isFree(), "Error: should be a free block"); |
|
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2859 _bt.verify_single_block((HeapWord*)fc, fc->size()); |
|
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2860 const size_t nn = fc->size() / word_sz; |
| 0 | 2861 n = MIN2(nn, n); |
|
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2862 assert((ssize_t)n >= 1, "Control point invariant"); |
| 0 | 2863 rem = fc->size() - n * word_sz; |
| 2864 // If there is a remainder, and it's too small, allocate one fewer. | |
| 2865 if (rem > 0 && rem < MinChunkSize) { | |
| 2866 n--; rem += word_sz; | |
| 2867 } | |
|
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2868 // Note that at this point we may have n == 0. |
|
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2869 assert((ssize_t)n >= 0, "Control point invariant"); |
|
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2870 |
|
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2871 // If n is 0, the chunk fc that was found is not large |
|
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2872 // enough to leave a viable remainder. We are unable to |
|
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2873 // allocate even one block. Return fc to the |
|
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2874 // dictionary and return, leaving "fl" empty. |
|
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2875 if (n == 0) { |
|
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2876 returnChunkToDictionary(fc); |
|
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2877 assert(fl->count() == 0, "We never allocated any blocks"); |
|
1148
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2878 return; |
|
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|
2879 } |
|
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2880 |
| 0 | 2881 // First return the remainder, if any. |
| 2882 // Note that we hold the lock until we decide if we're going to give | |
|
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2883 // back the remainder to the dictionary, since a concurrent allocation |
| 0 | 2884 // may otherwise see the heap as empty. (We're willing to take that |
| 2885 // hit if the block is a small block.) | |
| 2886 if (rem > 0) { | |
| 2887 size_t prefix_size = n * word_sz; | |
| 2888 rem_fc = (FreeChunk*)((HeapWord*)fc + prefix_size); | |
| 2889 rem_fc->setSize(rem); | |
|
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2890 rem_fc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. |
| 0 | 2891 rem_fc->linkNext(NULL); |
| 2892 // Above must occur before BOT is updated below. | |
|
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2893 assert((ssize_t)n > 0 && prefix_size > 0 && rem_fc > fc, "Error"); |
|
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2894 OrderAccess::storestore(); |
| 0 | 2895 _bt.split_block((HeapWord*)fc, fc->size(), prefix_size); |
|
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2896 assert(fc->isFree(), "Error"); |
|
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2897 fc->setSize(prefix_size); |
| 0 | 2898 if (rem >= IndexSetSize) { |
| 2899 returnChunkToDictionary(rem_fc); | |
|
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|
2900 dictionary()->dictCensusUpdate(rem, true /*split*/, true /*birth*/); |
| 0 | 2901 rem_fc = NULL; |
| 2902 } | |
| 2903 // Otherwise, return it to the small list below. | |
| 2904 } | |
| 2905 } | |
| 2906 if (rem_fc != NULL) { | |
| 2907 MutexLockerEx x(_indexedFreeListParLocks[rem], | |
| 2908 Mutex::_no_safepoint_check_flag); | |
| 2909 _bt.verify_not_unallocated((HeapWord*)rem_fc, rem_fc->size()); | |
| 2910 _indexedFreeList[rem].returnChunkAtHead(rem_fc); | |
| 2911 smallSplitBirth(rem); | |
| 2912 } | |
|
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|
2913 assert((ssize_t)n > 0 && fc != NULL, "Consistency"); |
| 0 | 2914 // Now do the splitting up. |
| 2915 // Must do this in reverse order, so that anybody attempting to | |
| 2916 // access the main chunk sees it as a single free block until we | |
| 2917 // change it. | |
| 2918 size_t fc_size = n * word_sz; | |
| 2919 // All but first chunk in this loop | |
| 2920 for (ssize_t i = n-1; i > 0; i--) { | |
| 2921 FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz); | |
| 2922 ffc->setSize(word_sz); | |
|
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|
2923 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. |
| 0 | 2924 ffc->linkNext(NULL); |
| 2925 // Above must occur before BOT is updated below. | |
|
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2926 OrderAccess::storestore(); |
| 0 | 2927 // splitting from the right, fc_size == (n - i + 1) * wordsize |
|
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2928 _bt.mark_block((HeapWord*)ffc, word_sz, true /* reducing */); |
| 0 | 2929 fc_size -= word_sz; |
| 2930 _bt.verify_not_unallocated((HeapWord*)ffc, ffc->size()); | |
| 2931 _bt.verify_single_block((HeapWord*)ffc, ffc->size()); | |
| 2932 _bt.verify_single_block((HeapWord*)fc, fc_size); | |
| 2933 // Push this on "fl". | |
| 2934 fl->returnChunkAtHead(ffc); | |
| 2935 } | |
| 2936 // First chunk | |
|
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2937 assert(fc->isFree() && fc->size() == n*word_sz, "Error: should still be a free block"); |
|
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2938 // The blocks above should show their new sizes before the first block below |
| 0 | 2939 fc->setSize(word_sz); |
|
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|
2940 fc->linkPrev(NULL); // idempotent wrt free-ness, see assert above |
| 0 | 2941 fc->linkNext(NULL); |
| 2942 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 2943 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 2944 fl->returnChunkAtHead(fc); | |
| 2945 | |
|
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2946 assert((ssize_t)n > 0 && (ssize_t)n == fl->count(), "Incorrect number of blocks"); |
| 0 | 2947 { |
|
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|
2948 // Update the stats for this block size. |
| 0 | 2949 MutexLockerEx x(_indexedFreeListParLocks[word_sz], |
| 2950 Mutex::_no_safepoint_check_flag); | |
|
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|
2951 const ssize_t births = _indexedFreeList[word_sz].splitBirths() + n; |
|
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2952 _indexedFreeList[word_sz].set_splitBirths(births); |
|
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2953 // ssize_t new_surplus = _indexedFreeList[word_sz].surplus() + n; |
|
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2954 // _indexedFreeList[word_sz].set_surplus(new_surplus); |
| 0 | 2955 } |
| 2956 | |
| 2957 // TRAP | |
| 2958 assert(fl->tail()->next() == NULL, "List invariant."); | |
| 2959 } | |
| 2960 | |
| 2961 // Set up the space's par_seq_tasks structure for work claiming | |
| 2962 // for parallel rescan. See CMSParRemarkTask where this is currently used. | |
| 2963 // XXX Need to suitably abstract and generalize this and the next | |
| 2964 // method into one. | |
| 2965 void | |
| 2966 CompactibleFreeListSpace:: | |
| 2967 initialize_sequential_subtasks_for_rescan(int n_threads) { | |
| 2968 // The "size" of each task is fixed according to rescan_task_size. | |
| 2969 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 2970 const size_t task_size = rescan_task_size(); | |
| 2971 size_t n_tasks = (used_region().word_size() + task_size - 1)/task_size; | |
|
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|
2972 assert((n_tasks == 0) == used_region().is_empty(), "n_tasks incorrect"); |
|
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2973 assert(n_tasks == 0 || |
|
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2974 ((used_region().start() + (n_tasks - 1)*task_size < used_region().end()) && |
|
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2975 (used_region().start() + n_tasks*task_size >= used_region().end())), |
|
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|
2976 "n_tasks calculation incorrect"); |
| 0 | 2977 SequentialSubTasksDone* pst = conc_par_seq_tasks(); |
| 2978 assert(!pst->valid(), "Clobbering existing data?"); | |
|
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2979 // Sets the condition for completion of the subtask (how many threads |
|
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|
2980 // need to finish in order to be done). |
|
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|
2981 pst->set_n_threads(n_threads); |
| 0 | 2982 pst->set_n_tasks((int)n_tasks); |
| 2983 } | |
| 2984 | |
| 2985 // Set up the space's par_seq_tasks structure for work claiming | |
| 2986 // for parallel concurrent marking. See CMSConcMarkTask where this is currently used. | |
| 2987 void | |
| 2988 CompactibleFreeListSpace:: | |
| 2989 initialize_sequential_subtasks_for_marking(int n_threads, | |
| 2990 HeapWord* low) { | |
| 2991 // The "size" of each task is fixed according to rescan_task_size. | |
| 2992 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 2993 const size_t task_size = marking_task_size(); | |
| 2994 assert(task_size > CardTableModRefBS::card_size_in_words && | |
| 2995 (task_size % CardTableModRefBS::card_size_in_words == 0), | |
| 2996 "Otherwise arithmetic below would be incorrect"); | |
| 2997 MemRegion span = _gen->reserved(); | |
| 2998 if (low != NULL) { | |
| 2999 if (span.contains(low)) { | |
| 3000 // Align low down to a card boundary so that | |
| 3001 // we can use block_offset_careful() on span boundaries. | |
| 3002 HeapWord* aligned_low = (HeapWord*)align_size_down((uintptr_t)low, | |
| 3003 CardTableModRefBS::card_size); | |
| 3004 // Clip span prefix at aligned_low | |
| 3005 span = span.intersection(MemRegion(aligned_low, span.end())); | |
| 3006 } else if (low > span.end()) { | |
| 3007 span = MemRegion(low, low); // Null region | |
| 3008 } // else use entire span | |
| 3009 } | |
| 3010 assert(span.is_empty() || | |
| 3011 ((uintptr_t)span.start() % CardTableModRefBS::card_size == 0), | |
| 3012 "span should start at a card boundary"); | |
| 3013 size_t n_tasks = (span.word_size() + task_size - 1)/task_size; | |
| 3014 assert((n_tasks == 0) == span.is_empty(), "Inconsistency"); | |
| 3015 assert(n_tasks == 0 || | |
| 3016 ((span.start() + (n_tasks - 1)*task_size < span.end()) && | |
| 3017 (span.start() + n_tasks*task_size >= span.end())), | |
|
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|
3018 "n_tasks calculation incorrect"); |
| 0 | 3019 SequentialSubTasksDone* pst = conc_par_seq_tasks(); |
| 3020 assert(!pst->valid(), "Clobbering existing data?"); | |
|
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3021 // Sets the condition for completion of the subtask (how many threads |
|
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6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3022 // need to finish in order to be done). |
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8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
jmasa
parents:
1777
diff
changeset
|
3023 pst->set_n_threads(n_threads); |
| 0 | 3024 pst->set_n_tasks((int)n_tasks); |
| 3025 } |