Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp @ 1777:179464550c7d
6983930: CMS: Various small cleanups ca September 2010
Summary: Fixed comment/documentation typos; converted some guarantee()s to assert()s.
Reviewed-by: jmasa
| author | ysr |
|---|---|
| date | Fri, 10 Sep 2010 17:07:55 -0700 |
| parents | be3f9c242c9d |
| children | 8b10f48633dc |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2001, 2010, 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 | |
| 25 # include "incls/_precompiled.incl" | |
| 26 # include "incls/_compactibleFreeListSpace.cpp.incl" | |
| 27 | |
| 28 ///////////////////////////////////////////////////////////////////////// | |
| 29 //// CompactibleFreeListSpace | |
| 30 ///////////////////////////////////////////////////////////////////////// | |
| 31 | |
| 32 // highest ranked free list lock rank | |
| 33 int CompactibleFreeListSpace::_lockRank = Mutex::leaf + 3; | |
| 34 | |
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35 // Defaults are 0 so things will break badly if incorrectly initialized. |
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36 int CompactibleFreeListSpace::IndexSetStart = 0; |
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37 int CompactibleFreeListSpace::IndexSetStride = 0; |
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38 |
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39 size_t MinChunkSize = 0; |
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40 |
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41 void CompactibleFreeListSpace::set_cms_values() { |
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42 // Set CMS global values |
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43 assert(MinChunkSize == 0, "already set"); |
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44 #define numQuanta(x,y) ((x+y-1)/y) |
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45 MinChunkSize = numQuanta(sizeof(FreeChunk), MinObjAlignmentInBytes) * MinObjAlignment; |
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46 |
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47 assert(IndexSetStart == 0 && IndexSetStride == 0, "already set"); |
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48 IndexSetStart = MinObjAlignment; |
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49 IndexSetStride = MinObjAlignment; |
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50 } |
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51 |
| 0 | 52 // Constructor |
| 53 CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs, | |
| 54 MemRegion mr, bool use_adaptive_freelists, | |
| 55 FreeBlockDictionary::DictionaryChoice dictionaryChoice) : | |
| 56 _dictionaryChoice(dictionaryChoice), | |
| 57 _adaptive_freelists(use_adaptive_freelists), | |
| 58 _bt(bs, mr), | |
| 59 // free list locks are in the range of values taken by _lockRank | |
| 60 // This range currently is [_leaf+2, _leaf+3] | |
| 61 // Note: this requires that CFLspace c'tors | |
| 62 // are called serially in the order in which the locks are | |
| 63 // are acquired in the program text. This is true today. | |
| 64 _freelistLock(_lockRank--, "CompactibleFreeListSpace._lock", true), | |
| 65 _parDictionaryAllocLock(Mutex::leaf - 1, // == rank(ExpandHeap_lock) - 1 | |
| 66 "CompactibleFreeListSpace._dict_par_lock", true), | |
| 67 _rescan_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord * | |
| 68 CMSRescanMultiple), | |
| 69 _marking_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord * | |
| 70 CMSConcMarkMultiple), | |
| 71 _collector(NULL) | |
| 72 { | |
| 73 _bt.set_space(this); | |
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74 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); |
| 0 | 75 // We have all of "mr", all of which we place in the dictionary |
| 76 // as one big chunk. We'll need to decide here which of several | |
| 77 // possible alternative dictionary implementations to use. For | |
| 78 // now the choice is easy, since we have only one working | |
| 79 // implementation, namely, the simple binary tree (splaying | |
| 80 // temporarily disabled). | |
| 81 switch (dictionaryChoice) { | |
| 82 case FreeBlockDictionary::dictionarySplayTree: | |
| 83 case FreeBlockDictionary::dictionarySkipList: | |
| 84 default: | |
| 85 warning("dictionaryChoice: selected option not understood; using" | |
| 86 " default BinaryTreeDictionary implementation instead."); | |
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87 case FreeBlockDictionary::dictionaryBinaryTree: |
| 0 | 88 _dictionary = new BinaryTreeDictionary(mr); |
| 89 break; | |
| 90 } | |
| 91 assert(_dictionary != NULL, "CMS dictionary initialization"); | |
| 92 // The indexed free lists are initially all empty and are lazily | |
| 93 // filled in on demand. Initialize the array elements to NULL. | |
| 94 initializeIndexedFreeListArray(); | |
| 95 | |
| 96 // Not using adaptive free lists assumes that allocation is first | |
| 97 // from the linAB's. Also a cms perm gen which can be compacted | |
| 98 // has to have the klass's klassKlass allocated at a lower | |
| 99 // address in the heap than the klass so that the klassKlass is | |
| 100 // moved to its new location before the klass is moved. | |
| 101 // Set the _refillSize for the linear allocation blocks | |
| 102 if (!use_adaptive_freelists) { | |
| 103 FreeChunk* fc = _dictionary->getChunk(mr.word_size()); | |
| 104 // The small linAB initially has all the space and will allocate | |
| 105 // a chunk of any size. | |
| 106 HeapWord* addr = (HeapWord*) fc; | |
| 107 _smallLinearAllocBlock.set(addr, fc->size() , | |
| 108 1024*SmallForLinearAlloc, fc->size()); | |
| 109 // Note that _unallocated_block is not updated here. | |
| 110 // Allocations from the linear allocation block should | |
| 111 // update it. | |
| 112 } else { | |
| 113 _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, | |
| 114 SmallForLinearAlloc); | |
| 115 } | |
| 116 // CMSIndexedFreeListReplenish should be at least 1 | |
| 117 CMSIndexedFreeListReplenish = MAX2((uintx)1, CMSIndexedFreeListReplenish); | |
| 118 _promoInfo.setSpace(this); | |
| 119 if (UseCMSBestFit) { | |
| 120 _fitStrategy = FreeBlockBestFitFirst; | |
| 121 } else { | |
| 122 _fitStrategy = FreeBlockStrategyNone; | |
| 123 } | |
| 124 checkFreeListConsistency(); | |
| 125 | |
| 126 // Initialize locks for parallel case. | |
| 127 if (ParallelGCThreads > 0) { | |
| 128 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 129 _indexedFreeListParLocks[i] = new Mutex(Mutex::leaf - 1, // == ExpandHeap_lock - 1 | |
| 130 "a freelist par lock", | |
| 131 true); | |
| 132 if (_indexedFreeListParLocks[i] == NULL) | |
| 133 vm_exit_during_initialization("Could not allocate a par lock"); | |
| 134 DEBUG_ONLY( | |
| 135 _indexedFreeList[i].set_protecting_lock(_indexedFreeListParLocks[i]); | |
| 136 ) | |
| 137 } | |
| 138 _dictionary->set_par_lock(&_parDictionaryAllocLock); | |
| 139 } | |
| 140 } | |
| 141 | |
| 142 // Like CompactibleSpace forward() but always calls cross_threshold() to | |
| 143 // update the block offset table. Removed initialize_threshold call because | |
| 144 // CFLS does not use a block offset array for contiguous spaces. | |
| 145 HeapWord* CompactibleFreeListSpace::forward(oop q, size_t size, | |
| 146 CompactPoint* cp, HeapWord* compact_top) { | |
| 147 // q is alive | |
| 148 // First check if we should switch compaction space | |
| 149 assert(this == cp->space, "'this' should be current compaction space."); | |
| 150 size_t compaction_max_size = pointer_delta(end(), compact_top); | |
| 151 assert(adjustObjectSize(size) == cp->space->adjust_object_size_v(size), | |
| 152 "virtual adjustObjectSize_v() method is not correct"); | |
| 153 size_t adjusted_size = adjustObjectSize(size); | |
| 154 assert(compaction_max_size >= MinChunkSize || compaction_max_size == 0, | |
| 155 "no small fragments allowed"); | |
| 156 assert(minimum_free_block_size() == MinChunkSize, | |
| 157 "for de-virtualized reference below"); | |
| 158 // Can't leave a nonzero size, residual fragment smaller than MinChunkSize | |
| 159 if (adjusted_size + MinChunkSize > compaction_max_size && | |
| 160 adjusted_size != compaction_max_size) { | |
| 161 do { | |
| 162 // switch to next compaction space | |
| 163 cp->space->set_compaction_top(compact_top); | |
| 164 cp->space = cp->space->next_compaction_space(); | |
| 165 if (cp->space == NULL) { | |
| 166 cp->gen = GenCollectedHeap::heap()->prev_gen(cp->gen); | |
| 167 assert(cp->gen != NULL, "compaction must succeed"); | |
| 168 cp->space = cp->gen->first_compaction_space(); | |
| 169 assert(cp->space != NULL, "generation must have a first compaction space"); | |
| 170 } | |
| 171 compact_top = cp->space->bottom(); | |
| 172 cp->space->set_compaction_top(compact_top); | |
| 173 // The correct adjusted_size may not be the same as that for this method | |
| 174 // (i.e., cp->space may no longer be "this" so adjust the size again. | |
| 175 // Use the virtual method which is not used above to save the virtual | |
| 176 // dispatch. | |
| 177 adjusted_size = cp->space->adjust_object_size_v(size); | |
| 178 compaction_max_size = pointer_delta(cp->space->end(), compact_top); | |
| 179 assert(cp->space->minimum_free_block_size() == 0, "just checking"); | |
| 180 } while (adjusted_size > compaction_max_size); | |
| 181 } | |
| 182 | |
| 183 // store the forwarding pointer into the mark word | |
| 184 if ((HeapWord*)q != compact_top) { | |
| 185 q->forward_to(oop(compact_top)); | |
| 186 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); | |
| 187 } else { | |
| 188 // if the object isn't moving we can just set the mark to the default | |
| 189 // mark and handle it specially later on. | |
| 190 q->init_mark(); | |
| 191 assert(q->forwardee() == NULL, "should be forwarded to NULL"); | |
| 192 } | |
| 193 | |
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194 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::register_live_oop(q, adjusted_size)); |
| 0 | 195 compact_top += adjusted_size; |
| 196 | |
| 197 // we need to update the offset table so that the beginnings of objects can be | |
| 198 // found during scavenge. Note that we are updating the offset table based on | |
| 199 // where the object will be once the compaction phase finishes. | |
| 200 | |
| 201 // Always call cross_threshold(). A contiguous space can only call it when | |
| 202 // the compaction_top exceeds the current threshold but not for an | |
| 203 // non-contiguous space. | |
| 204 cp->threshold = | |
| 205 cp->space->cross_threshold(compact_top - adjusted_size, compact_top); | |
| 206 return compact_top; | |
| 207 } | |
| 208 | |
| 209 // A modified copy of OffsetTableContigSpace::cross_threshold() with _offsets -> _bt | |
| 210 // and use of single_block instead of alloc_block. The name here is not really | |
| 211 // appropriate - maybe a more general name could be invented for both the | |
| 212 // contiguous and noncontiguous spaces. | |
| 213 | |
| 214 HeapWord* CompactibleFreeListSpace::cross_threshold(HeapWord* start, HeapWord* the_end) { | |
| 215 _bt.single_block(start, the_end); | |
| 216 return end(); | |
| 217 } | |
| 218 | |
| 219 // Initialize them to NULL. | |
| 220 void CompactibleFreeListSpace::initializeIndexedFreeListArray() { | |
| 221 for (size_t i = 0; i < IndexSetSize; i++) { | |
| 222 // Note that on platforms where objects are double word aligned, | |
| 223 // the odd array elements are not used. It is convenient, however, | |
| 224 // to map directly from the object size to the array element. | |
| 225 _indexedFreeList[i].reset(IndexSetSize); | |
| 226 _indexedFreeList[i].set_size(i); | |
| 227 assert(_indexedFreeList[i].count() == 0, "reset check failed"); | |
| 228 assert(_indexedFreeList[i].head() == NULL, "reset check failed"); | |
| 229 assert(_indexedFreeList[i].tail() == NULL, "reset check failed"); | |
| 230 assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed"); | |
| 231 } | |
| 232 } | |
| 233 | |
| 234 void CompactibleFreeListSpace::resetIndexedFreeListArray() { | |
| 235 for (int i = 1; i < IndexSetSize; i++) { | |
| 236 assert(_indexedFreeList[i].size() == (size_t) i, | |
| 237 "Indexed free list sizes are incorrect"); | |
| 238 _indexedFreeList[i].reset(IndexSetSize); | |
| 239 assert(_indexedFreeList[i].count() == 0, "reset check failed"); | |
| 240 assert(_indexedFreeList[i].head() == NULL, "reset check failed"); | |
| 241 assert(_indexedFreeList[i].tail() == NULL, "reset check failed"); | |
| 242 assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed"); | |
| 243 } | |
| 244 } | |
| 245 | |
| 246 void CompactibleFreeListSpace::reset(MemRegion mr) { | |
| 247 resetIndexedFreeListArray(); | |
| 248 dictionary()->reset(); | |
| 249 if (BlockOffsetArrayUseUnallocatedBlock) { | |
| 250 assert(end() == mr.end(), "We are compacting to the bottom of CMS gen"); | |
| 251 // Everything's allocated until proven otherwise. | |
| 252 _bt.set_unallocated_block(end()); | |
| 253 } | |
| 254 if (!mr.is_empty()) { | |
| 255 assert(mr.word_size() >= MinChunkSize, "Chunk size is too small"); | |
| 256 _bt.single_block(mr.start(), mr.word_size()); | |
| 257 FreeChunk* fc = (FreeChunk*) mr.start(); | |
| 258 fc->setSize(mr.word_size()); | |
| 259 if (mr.word_size() >= IndexSetSize ) { | |
| 260 returnChunkToDictionary(fc); | |
| 261 } else { | |
| 262 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 263 _indexedFreeList[mr.word_size()].returnChunkAtHead(fc); | |
| 264 } | |
| 265 } | |
| 266 _promoInfo.reset(); | |
| 267 _smallLinearAllocBlock._ptr = NULL; | |
| 268 _smallLinearAllocBlock._word_size = 0; | |
| 269 } | |
| 270 | |
| 271 void CompactibleFreeListSpace::reset_after_compaction() { | |
| 272 // Reset the space to the new reality - one free chunk. | |
| 273 MemRegion mr(compaction_top(), end()); | |
| 274 reset(mr); | |
| 275 // Now refill the linear allocation block(s) if possible. | |
| 276 if (_adaptive_freelists) { | |
| 277 refillLinearAllocBlocksIfNeeded(); | |
| 278 } else { | |
| 279 // Place as much of mr in the linAB as we can get, | |
| 280 // provided it was big enough to go into the dictionary. | |
| 281 FreeChunk* fc = dictionary()->findLargestDict(); | |
| 282 if (fc != NULL) { | |
| 283 assert(fc->size() == mr.word_size(), | |
| 284 "Why was the chunk broken up?"); | |
| 285 removeChunkFromDictionary(fc); | |
| 286 HeapWord* addr = (HeapWord*) fc; | |
| 287 _smallLinearAllocBlock.set(addr, fc->size() , | |
| 288 1024*SmallForLinearAlloc, fc->size()); | |
| 289 // Note that _unallocated_block is not updated here. | |
| 290 } | |
| 291 } | |
| 292 } | |
| 293 | |
| 294 // Walks the entire dictionary, returning a coterminal | |
| 295 // chunk, if it exists. Use with caution since it involves | |
| 296 // a potentially complete walk of a potentially large tree. | |
| 297 FreeChunk* CompactibleFreeListSpace::find_chunk_at_end() { | |
| 298 | |
| 299 assert_lock_strong(&_freelistLock); | |
| 300 | |
| 301 return dictionary()->find_chunk_ends_at(end()); | |
| 302 } | |
| 303 | |
| 304 | |
| 305 #ifndef PRODUCT | |
| 306 void CompactibleFreeListSpace::initializeIndexedFreeListArrayReturnedBytes() { | |
| 307 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 308 _indexedFreeList[i].allocation_stats()->set_returnedBytes(0); | |
| 309 } | |
| 310 } | |
| 311 | |
| 312 size_t CompactibleFreeListSpace::sumIndexedFreeListArrayReturnedBytes() { | |
| 313 size_t sum = 0; | |
| 314 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 315 sum += _indexedFreeList[i].allocation_stats()->returnedBytes(); | |
| 316 } | |
| 317 return sum; | |
| 318 } | |
| 319 | |
| 320 size_t CompactibleFreeListSpace::totalCountInIndexedFreeLists() const { | |
| 321 size_t count = 0; | |
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322 for (int i = (int)MinChunkSize; i < IndexSetSize; i++) { |
| 0 | 323 debug_only( |
| 324 ssize_t total_list_count = 0; | |
| 325 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 326 fc = fc->next()) { | |
| 327 total_list_count++; | |
| 328 } | |
| 329 assert(total_list_count == _indexedFreeList[i].count(), | |
| 330 "Count in list is incorrect"); | |
| 331 ) | |
| 332 count += _indexedFreeList[i].count(); | |
| 333 } | |
| 334 return count; | |
| 335 } | |
| 336 | |
| 337 size_t CompactibleFreeListSpace::totalCount() { | |
| 338 size_t num = totalCountInIndexedFreeLists(); | |
| 339 num += dictionary()->totalCount(); | |
| 340 if (_smallLinearAllocBlock._word_size != 0) { | |
| 341 num++; | |
| 342 } | |
| 343 return num; | |
| 344 } | |
| 345 #endif | |
| 346 | |
| 347 bool CompactibleFreeListSpace::is_free_block(const HeapWord* p) const { | |
| 348 FreeChunk* fc = (FreeChunk*) p; | |
| 349 return fc->isFree(); | |
| 350 } | |
| 351 | |
| 352 size_t CompactibleFreeListSpace::used() const { | |
| 353 return capacity() - free(); | |
| 354 } | |
| 355 | |
| 356 size_t CompactibleFreeListSpace::free() const { | |
| 357 // "MT-safe, but not MT-precise"(TM), if you will: i.e. | |
| 358 // if you do this while the structures are in flux you | |
| 359 // may get an approximate answer only; for instance | |
| 360 // because there is concurrent allocation either | |
| 361 // directly by mutators or for promotion during a GC. | |
| 362 // It's "MT-safe", however, in the sense that you are guaranteed | |
| 363 // not to crash and burn, for instance, because of walking | |
| 364 // pointers that could disappear as you were walking them. | |
| 365 // The approximation is because the various components | |
| 366 // that are read below are not read atomically (and | |
| 367 // further the computation of totalSizeInIndexedFreeLists() | |
| 368 // is itself a non-atomic computation. The normal use of | |
| 369 // this is during a resize operation at the end of GC | |
| 370 // and at that time you are guaranteed to get the | |
| 371 // correct actual value. However, for instance, this is | |
| 372 // also read completely asynchronously by the "perf-sampler" | |
| 373 // that supports jvmstat, and you are apt to see the values | |
| 374 // flicker in such cases. | |
| 375 assert(_dictionary != NULL, "No _dictionary?"); | |
| 376 return (_dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())) + | |
| 377 totalSizeInIndexedFreeLists() + | |
| 378 _smallLinearAllocBlock._word_size) * HeapWordSize; | |
| 379 } | |
| 380 | |
| 381 size_t CompactibleFreeListSpace::max_alloc_in_words() const { | |
| 382 assert(_dictionary != NULL, "No _dictionary?"); | |
| 383 assert_locked(); | |
| 384 size_t res = _dictionary->maxChunkSize(); | |
| 385 res = MAX2(res, MIN2(_smallLinearAllocBlock._word_size, | |
| 386 (size_t) SmallForLinearAlloc - 1)); | |
| 387 // XXX the following could potentially be pretty slow; | |
| 388 // should one, pesimally for the rare cases when res | |
| 389 // caclulated above is less than IndexSetSize, | |
| 390 // just return res calculated above? My reasoning was that | |
| 391 // those cases will be so rare that the extra time spent doesn't | |
| 392 // really matter.... | |
| 393 // Note: do not change the loop test i >= res + IndexSetStride | |
| 394 // to i > res below, because i is unsigned and res may be zero. | |
| 395 for (size_t i = IndexSetSize - 1; i >= res + IndexSetStride; | |
| 396 i -= IndexSetStride) { | |
| 397 if (_indexedFreeList[i].head() != NULL) { | |
| 398 assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList"); | |
| 399 return i; | |
| 400 } | |
| 401 } | |
| 402 return res; | |
| 403 } | |
| 404 | |
|
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405 void LinearAllocBlock::print_on(outputStream* st) const { |
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406 st->print_cr(" LinearAllocBlock: ptr = " PTR_FORMAT ", word_size = " SIZE_FORMAT |
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407 ", refillsize = " SIZE_FORMAT ", allocation_size_limit = " SIZE_FORMAT, |
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408 _ptr, _word_size, _refillSize, _allocation_size_limit); |
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409 } |
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410 |
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411 void CompactibleFreeListSpace::print_on(outputStream* st) const { |
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412 st->print_cr("COMPACTIBLE FREELIST SPACE"); |
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413 st->print_cr(" Space:"); |
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414 Space::print_on(st); |
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415 |
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416 st->print_cr("promoInfo:"); |
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417 _promoInfo.print_on(st); |
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418 |
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419 st->print_cr("_smallLinearAllocBlock"); |
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420 _smallLinearAllocBlock.print_on(st); |
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421 |
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422 // dump_memory_block(_smallLinearAllocBlock->_ptr, 128); |
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423 |
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424 st->print_cr(" _fitStrategy = %s, _adaptive_freelists = %s", |
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425 _fitStrategy?"true":"false", _adaptive_freelists?"true":"false"); |
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426 } |
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427 |
|
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428 void CompactibleFreeListSpace::print_indexed_free_lists(outputStream* st) |
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429 const { |
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430 reportIndexedFreeListStatistics(); |
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431 gclog_or_tty->print_cr("Layout of Indexed Freelists"); |
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432 gclog_or_tty->print_cr("---------------------------"); |
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433 FreeList::print_labels_on(st, "size"); |
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434 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { |
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435 _indexedFreeList[i].print_on(gclog_or_tty); |
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436 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; |
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437 fc = fc->next()) { |
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438 gclog_or_tty->print_cr("\t[" PTR_FORMAT "," PTR_FORMAT ") %s", |
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439 fc, (HeapWord*)fc + i, |
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440 fc->cantCoalesce() ? "\t CC" : ""); |
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441 } |
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442 } |
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443 } |
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444 |
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445 void CompactibleFreeListSpace::print_promo_info_blocks(outputStream* st) |
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446 const { |
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447 _promoInfo.print_on(st); |
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448 } |
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449 |
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450 void CompactibleFreeListSpace::print_dictionary_free_lists(outputStream* st) |
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451 const { |
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452 _dictionary->reportStatistics(); |
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453 st->print_cr("Layout of Freelists in Tree"); |
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454 st->print_cr("---------------------------"); |
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455 _dictionary->print_free_lists(st); |
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456 } |
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457 |
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458 class BlkPrintingClosure: public BlkClosure { |
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459 const CMSCollector* _collector; |
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460 const CompactibleFreeListSpace* _sp; |
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461 const CMSBitMap* _live_bit_map; |
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462 const bool _post_remark; |
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463 outputStream* _st; |
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464 public: |
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465 BlkPrintingClosure(const CMSCollector* collector, |
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466 const CompactibleFreeListSpace* sp, |
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467 const CMSBitMap* live_bit_map, |
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468 outputStream* st): |
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469 _collector(collector), |
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470 _sp(sp), |
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471 _live_bit_map(live_bit_map), |
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472 _post_remark(collector->abstract_state() > CMSCollector::FinalMarking), |
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473 _st(st) { } |
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474 size_t do_blk(HeapWord* addr); |
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475 }; |
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476 |
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477 size_t BlkPrintingClosure::do_blk(HeapWord* addr) { |
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478 size_t sz = _sp->block_size_no_stall(addr, _collector); |
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479 assert(sz != 0, "Should always be able to compute a size"); |
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480 if (_sp->block_is_obj(addr)) { |
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481 const bool dead = _post_remark && !_live_bit_map->isMarked(addr); |
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482 _st->print_cr(PTR_FORMAT ": %s object of size " SIZE_FORMAT "%s", |
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483 addr, |
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484 dead ? "dead" : "live", |
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485 sz, |
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486 (!dead && CMSPrintObjectsInDump) ? ":" : "."); |
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487 if (CMSPrintObjectsInDump && !dead) { |
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488 oop(addr)->print_on(_st); |
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489 _st->print_cr("--------------------------------------"); |
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490 } |
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491 } else { // free block |
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492 _st->print_cr(PTR_FORMAT ": free block of size " SIZE_FORMAT "%s", |
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493 addr, sz, CMSPrintChunksInDump ? ":" : "."); |
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494 if (CMSPrintChunksInDump) { |
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495 ((FreeChunk*)addr)->print_on(_st); |
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496 _st->print_cr("--------------------------------------"); |
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497 } |
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498 } |
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499 return sz; |
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500 } |
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501 |
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502 void CompactibleFreeListSpace::dump_at_safepoint_with_locks(CMSCollector* c, |
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503 outputStream* st) { |
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504 st->print_cr("\n========================="); |
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505 st->print_cr("Block layout in CMS Heap:"); |
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506 st->print_cr("========================="); |
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507 BlkPrintingClosure bpcl(c, this, c->markBitMap(), st); |
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508 blk_iterate(&bpcl); |
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509 |
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510 st->print_cr("\n======================================="); |
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511 st->print_cr("Order & Layout of Promotion Info Blocks"); |
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512 st->print_cr("======================================="); |
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513 print_promo_info_blocks(st); |
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514 |
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515 st->print_cr("\n==========================="); |
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516 st->print_cr("Order of Indexed Free Lists"); |
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517 st->print_cr("========================="); |
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518 print_indexed_free_lists(st); |
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519 |
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520 st->print_cr("\n================================="); |
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521 st->print_cr("Order of Free Lists in Dictionary"); |
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522 st->print_cr("================================="); |
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523 print_dictionary_free_lists(st); |
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524 } |
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525 |
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526 |
| 0 | 527 void CompactibleFreeListSpace::reportFreeListStatistics() const { |
| 528 assert_lock_strong(&_freelistLock); | |
| 529 assert(PrintFLSStatistics != 0, "Reporting error"); | |
| 530 _dictionary->reportStatistics(); | |
| 531 if (PrintFLSStatistics > 1) { | |
| 532 reportIndexedFreeListStatistics(); | |
| 533 size_t totalSize = totalSizeInIndexedFreeLists() + | |
| 534 _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())); | |
| 535 gclog_or_tty->print(" free=%ld frag=%1.4f\n", totalSize, flsFrag()); | |
| 536 } | |
| 537 } | |
| 538 | |
| 539 void CompactibleFreeListSpace::reportIndexedFreeListStatistics() const { | |
| 540 assert_lock_strong(&_freelistLock); | |
| 541 gclog_or_tty->print("Statistics for IndexedFreeLists:\n" | |
| 542 "--------------------------------\n"); | |
| 543 size_t totalSize = totalSizeInIndexedFreeLists(); | |
| 544 size_t freeBlocks = numFreeBlocksInIndexedFreeLists(); | |
| 545 gclog_or_tty->print("Total Free Space: %d\n", totalSize); | |
| 546 gclog_or_tty->print("Max Chunk Size: %d\n", maxChunkSizeInIndexedFreeLists()); | |
| 547 gclog_or_tty->print("Number of Blocks: %d\n", freeBlocks); | |
| 548 if (freeBlocks != 0) { | |
| 549 gclog_or_tty->print("Av. Block Size: %d\n", totalSize/freeBlocks); | |
| 550 } | |
| 551 } | |
| 552 | |
| 553 size_t CompactibleFreeListSpace::numFreeBlocksInIndexedFreeLists() const { | |
| 554 size_t res = 0; | |
| 555 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 556 debug_only( | |
| 557 ssize_t recount = 0; | |
| 558 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 559 fc = fc->next()) { | |
| 560 recount += 1; | |
| 561 } | |
| 562 assert(recount == _indexedFreeList[i].count(), | |
| 563 "Incorrect count in list"); | |
| 564 ) | |
| 565 res += _indexedFreeList[i].count(); | |
| 566 } | |
| 567 return res; | |
| 568 } | |
| 569 | |
| 570 size_t CompactibleFreeListSpace::maxChunkSizeInIndexedFreeLists() const { | |
| 571 for (size_t i = IndexSetSize - 1; i != 0; i -= IndexSetStride) { | |
| 572 if (_indexedFreeList[i].head() != NULL) { | |
| 573 assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList"); | |
| 574 return (size_t)i; | |
| 575 } | |
| 576 } | |
| 577 return 0; | |
| 578 } | |
| 579 | |
| 580 void CompactibleFreeListSpace::set_end(HeapWord* value) { | |
| 581 HeapWord* prevEnd = end(); | |
| 582 assert(prevEnd != value, "unnecessary set_end call"); | |
|
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583 assert(prevEnd == NULL || !BlockOffsetArrayUseUnallocatedBlock || value >= unallocated_block(), |
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584 "New end is below unallocated block"); |
| 0 | 585 _end = value; |
| 586 if (prevEnd != NULL) { | |
| 587 // Resize the underlying block offset table. | |
| 588 _bt.resize(pointer_delta(value, bottom())); | |
|
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589 if (value <= prevEnd) { |
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590 assert(!BlockOffsetArrayUseUnallocatedBlock || value >= unallocated_block(), |
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591 "New end is below unallocated block"); |
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592 } else { |
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593 // Now, take this new chunk and add it to the free blocks. |
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594 // Note that the BOT has not yet been updated for this block. |
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595 size_t newFcSize = pointer_delta(value, prevEnd); |
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596 // XXX This is REALLY UGLY and should be fixed up. XXX |
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597 if (!_adaptive_freelists && _smallLinearAllocBlock._ptr == NULL) { |
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598 // Mark the boundary of the new block in BOT |
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599 _bt.mark_block(prevEnd, value); |
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600 // put it all in the linAB |
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601 if (ParallelGCThreads == 0) { |
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602 _smallLinearAllocBlock._ptr = prevEnd; |
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603 _smallLinearAllocBlock._word_size = newFcSize; |
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604 repairLinearAllocBlock(&_smallLinearAllocBlock); |
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605 } else { // ParallelGCThreads > 0 |
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606 MutexLockerEx x(parDictionaryAllocLock(), |
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607 Mutex::_no_safepoint_check_flag); |
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608 _smallLinearAllocBlock._ptr = prevEnd; |
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609 _smallLinearAllocBlock._word_size = newFcSize; |
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610 repairLinearAllocBlock(&_smallLinearAllocBlock); |
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611 } |
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612 // Births of chunks put into a LinAB are not recorded. Births |
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613 // of chunks as they are allocated out of a LinAB are. |
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614 } else { |
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615 // Add the block to the free lists, if possible coalescing it |
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616 // with the last free block, and update the BOT and census data. |
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617 addChunkToFreeListsAtEndRecordingStats(prevEnd, newFcSize); |
| 0 | 618 } |
| 619 } | |
| 620 } | |
| 621 } | |
| 622 | |
| 623 class FreeListSpace_DCTOC : public Filtering_DCTOC { | |
| 624 CompactibleFreeListSpace* _cfls; | |
| 625 CMSCollector* _collector; | |
| 626 protected: | |
| 627 // Override. | |
| 628 #define walk_mem_region_with_cl_DECL(ClosureType) \ | |
| 629 virtual void walk_mem_region_with_cl(MemRegion mr, \ | |
| 630 HeapWord* bottom, HeapWord* top, \ | |
| 631 ClosureType* cl); \ | |
| 632 void walk_mem_region_with_cl_par(MemRegion mr, \ | |
| 633 HeapWord* bottom, HeapWord* top, \ | |
| 634 ClosureType* cl); \ | |
| 635 void walk_mem_region_with_cl_nopar(MemRegion mr, \ | |
| 636 HeapWord* bottom, HeapWord* top, \ | |
| 637 ClosureType* cl) | |
| 638 walk_mem_region_with_cl_DECL(OopClosure); | |
| 639 walk_mem_region_with_cl_DECL(FilteringClosure); | |
| 640 | |
| 641 public: | |
| 642 FreeListSpace_DCTOC(CompactibleFreeListSpace* sp, | |
| 643 CMSCollector* collector, | |
| 644 OopClosure* cl, | |
| 645 CardTableModRefBS::PrecisionStyle precision, | |
| 646 HeapWord* boundary) : | |
| 647 Filtering_DCTOC(sp, cl, precision, boundary), | |
| 648 _cfls(sp), _collector(collector) {} | |
| 649 }; | |
| 650 | |
| 651 // We de-virtualize the block-related calls below, since we know that our | |
| 652 // space is a CompactibleFreeListSpace. | |
| 653 #define FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ | |
| 654 void FreeListSpace_DCTOC::walk_mem_region_with_cl(MemRegion mr, \ | |
| 655 HeapWord* bottom, \ | |
| 656 HeapWord* top, \ | |
| 657 ClosureType* cl) { \ | |
| 658 if (SharedHeap::heap()->n_par_threads() > 0) { \ | |
| 659 walk_mem_region_with_cl_par(mr, bottom, top, cl); \ | |
| 660 } else { \ | |
| 661 walk_mem_region_with_cl_nopar(mr, bottom, top, cl); \ | |
| 662 } \ | |
| 663 } \ | |
| 664 void FreeListSpace_DCTOC::walk_mem_region_with_cl_par(MemRegion mr, \ | |
| 665 HeapWord* bottom, \ | |
| 666 HeapWord* top, \ | |
| 667 ClosureType* cl) { \ | |
| 668 /* Skip parts that are before "mr", in case "block_start" sent us \ | |
| 669 back too far. */ \ | |
| 670 HeapWord* mr_start = mr.start(); \ | |
| 671 size_t bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 672 HeapWord* next = bottom + bot_size; \ | |
| 673 while (next < mr_start) { \ | |
| 674 bottom = next; \ | |
| 675 bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 676 next = bottom + bot_size; \ | |
| 677 } \ | |
| 678 \ | |
| 679 while (bottom < top) { \ | |
| 680 if (_cfls->CompactibleFreeListSpace::block_is_obj(bottom) && \ | |
| 681 !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks( \ | |
| 682 oop(bottom)) && \ | |
| 683 !_collector->CMSCollector::is_dead_obj(oop(bottom))) { \ | |
| 684 size_t word_sz = oop(bottom)->oop_iterate(cl, mr); \ | |
| 685 bottom += _cfls->adjustObjectSize(word_sz); \ | |
| 686 } else { \ | |
| 687 bottom += _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 688 } \ | |
| 689 } \ | |
| 690 } \ | |
| 691 void FreeListSpace_DCTOC::walk_mem_region_with_cl_nopar(MemRegion mr, \ | |
| 692 HeapWord* bottom, \ | |
| 693 HeapWord* top, \ | |
| 694 ClosureType* cl) { \ | |
| 695 /* Skip parts that are before "mr", in case "block_start" sent us \ | |
| 696 back too far. */ \ | |
| 697 HeapWord* mr_start = mr.start(); \ | |
| 698 size_t bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 699 HeapWord* next = bottom + bot_size; \ | |
| 700 while (next < mr_start) { \ | |
| 701 bottom = next; \ | |
| 702 bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 703 next = bottom + bot_size; \ | |
| 704 } \ | |
| 705 \ | |
| 706 while (bottom < top) { \ | |
| 707 if (_cfls->CompactibleFreeListSpace::block_is_obj_nopar(bottom) && \ | |
| 708 !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks( \ | |
| 709 oop(bottom)) && \ | |
| 710 !_collector->CMSCollector::is_dead_obj(oop(bottom))) { \ | |
| 711 size_t word_sz = oop(bottom)->oop_iterate(cl, mr); \ | |
| 712 bottom += _cfls->adjustObjectSize(word_sz); \ | |
| 713 } else { \ | |
| 714 bottom += _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 715 } \ | |
| 716 } \ | |
| 717 } | |
| 718 | |
| 719 // (There are only two of these, rather than N, because the split is due | |
| 720 // only to the introduction of the FilteringClosure, a local part of the | |
| 721 // impl of this abstraction.) | |
| 722 FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(OopClosure) | |
| 723 FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) | |
| 724 | |
| 725 DirtyCardToOopClosure* | |
| 726 CompactibleFreeListSpace::new_dcto_cl(OopClosure* cl, | |
| 727 CardTableModRefBS::PrecisionStyle precision, | |
| 728 HeapWord* boundary) { | |
| 729 return new FreeListSpace_DCTOC(this, _collector, cl, precision, boundary); | |
| 730 } | |
| 731 | |
| 732 | |
| 733 // Note on locking for the space iteration functions: | |
| 734 // since the collector's iteration activities are concurrent with | |
| 735 // allocation activities by mutators, absent a suitable mutual exclusion | |
| 736 // mechanism the iterators may go awry. For instace a block being iterated | |
| 737 // may suddenly be allocated or divided up and part of it allocated and | |
| 738 // so on. | |
| 739 | |
| 740 // Apply the given closure to each block in the space. | |
| 741 void CompactibleFreeListSpace::blk_iterate_careful(BlkClosureCareful* cl) { | |
| 742 assert_lock_strong(freelistLock()); | |
| 743 HeapWord *cur, *limit; | |
| 744 for (cur = bottom(), limit = end(); cur < limit; | |
| 745 cur += cl->do_blk_careful(cur)); | |
| 746 } | |
| 747 | |
| 748 // Apply the given closure to each block in the space. | |
| 749 void CompactibleFreeListSpace::blk_iterate(BlkClosure* cl) { | |
| 750 assert_lock_strong(freelistLock()); | |
| 751 HeapWord *cur, *limit; | |
| 752 for (cur = bottom(), limit = end(); cur < limit; | |
| 753 cur += cl->do_blk(cur)); | |
| 754 } | |
| 755 | |
| 756 // Apply the given closure to each oop in the space. | |
| 757 void CompactibleFreeListSpace::oop_iterate(OopClosure* cl) { | |
| 758 assert_lock_strong(freelistLock()); | |
| 759 HeapWord *cur, *limit; | |
| 760 size_t curSize; | |
| 761 for (cur = bottom(), limit = end(); cur < limit; | |
| 762 cur += curSize) { | |
| 763 curSize = block_size(cur); | |
| 764 if (block_is_obj(cur)) { | |
| 765 oop(cur)->oop_iterate(cl); | |
| 766 } | |
| 767 } | |
| 768 } | |
| 769 | |
| 770 // Apply the given closure to each oop in the space \intersect memory region. | |
| 771 void CompactibleFreeListSpace::oop_iterate(MemRegion mr, OopClosure* cl) { | |
| 772 assert_lock_strong(freelistLock()); | |
| 773 if (is_empty()) { | |
| 774 return; | |
| 775 } | |
| 776 MemRegion cur = MemRegion(bottom(), end()); | |
| 777 mr = mr.intersection(cur); | |
| 778 if (mr.is_empty()) { | |
| 779 return; | |
| 780 } | |
| 781 if (mr.equals(cur)) { | |
| 782 oop_iterate(cl); | |
| 783 return; | |
| 784 } | |
| 785 assert(mr.end() <= end(), "just took an intersection above"); | |
| 786 HeapWord* obj_addr = block_start(mr.start()); | |
| 787 HeapWord* t = mr.end(); | |
| 788 | |
| 789 SpaceMemRegionOopsIterClosure smr_blk(cl, mr); | |
| 790 if (block_is_obj(obj_addr)) { | |
| 791 // Handle first object specially. | |
| 792 oop obj = oop(obj_addr); | |
| 793 obj_addr += adjustObjectSize(obj->oop_iterate(&smr_blk)); | |
| 794 } else { | |
| 795 FreeChunk* fc = (FreeChunk*)obj_addr; | |
| 796 obj_addr += fc->size(); | |
| 797 } | |
| 798 while (obj_addr < t) { | |
| 799 HeapWord* obj = obj_addr; | |
| 800 obj_addr += block_size(obj_addr); | |
| 801 // If "obj_addr" is not greater than top, then the | |
| 802 // entire object "obj" is within the region. | |
| 803 if (obj_addr <= t) { | |
| 804 if (block_is_obj(obj)) { | |
| 805 oop(obj)->oop_iterate(cl); | |
| 806 } | |
| 807 } else { | |
| 808 // "obj" extends beyond end of region | |
| 809 if (block_is_obj(obj)) { | |
| 810 oop(obj)->oop_iterate(&smr_blk); | |
| 811 } | |
| 812 break; | |
| 813 } | |
| 814 } | |
| 815 } | |
| 816 | |
| 817 // NOTE: In the following methods, in order to safely be able to | |
| 818 // apply the closure to an object, we need to be sure that the | |
| 819 // object has been initialized. We are guaranteed that an object | |
| 820 // is initialized if we are holding the Heap_lock with the | |
| 821 // world stopped. | |
| 822 void CompactibleFreeListSpace::verify_objects_initialized() const { | |
| 823 if (is_init_completed()) { | |
| 824 assert_locked_or_safepoint(Heap_lock); | |
| 825 if (Universe::is_fully_initialized()) { | |
| 826 guarantee(SafepointSynchronize::is_at_safepoint(), | |
| 827 "Required for objects to be initialized"); | |
| 828 } | |
| 829 } // else make a concession at vm start-up | |
| 830 } | |
| 831 | |
| 832 // Apply the given closure to each object in the space | |
| 833 void CompactibleFreeListSpace::object_iterate(ObjectClosure* blk) { | |
| 834 assert_lock_strong(freelistLock()); | |
| 835 NOT_PRODUCT(verify_objects_initialized()); | |
| 836 HeapWord *cur, *limit; | |
| 837 size_t curSize; | |
| 838 for (cur = bottom(), limit = end(); cur < limit; | |
| 839 cur += curSize) { | |
| 840 curSize = block_size(cur); | |
| 841 if (block_is_obj(cur)) { | |
| 842 blk->do_object(oop(cur)); | |
| 843 } | |
| 844 } | |
| 845 } | |
| 846 | |
|
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847 // Apply the given closure to each live object in the space |
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848 // The usage of CompactibleFreeListSpace |
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849 // by the ConcurrentMarkSweepGeneration for concurrent GC's allows |
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850 // objects in the space with references to objects that are no longer |
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851 // valid. For example, an object may reference another object |
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852 // that has already been sweep up (collected). This method uses |
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853 // obj_is_alive() to determine whether it is safe to apply the closure to |
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854 // an object. See obj_is_alive() for details on how liveness of an |
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855 // object is decided. |
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856 |
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857 void CompactibleFreeListSpace::safe_object_iterate(ObjectClosure* blk) { |
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858 assert_lock_strong(freelistLock()); |
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859 NOT_PRODUCT(verify_objects_initialized()); |
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860 HeapWord *cur, *limit; |
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861 size_t curSize; |
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862 for (cur = bottom(), limit = end(); cur < limit; |
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863 cur += curSize) { |
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864 curSize = block_size(cur); |
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865 if (block_is_obj(cur) && obj_is_alive(cur)) { |
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866 blk->do_object(oop(cur)); |
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867 } |
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868 } |
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869 } |
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870 |
| 0 | 871 void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr, |
| 872 UpwardsObjectClosure* cl) { | |
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873 assert_locked(freelistLock()); |
| 0 | 874 NOT_PRODUCT(verify_objects_initialized()); |
| 875 Space::object_iterate_mem(mr, cl); | |
| 876 } | |
| 877 | |
| 878 // Callers of this iterator beware: The closure application should | |
| 879 // be robust in the face of uninitialized objects and should (always) | |
| 880 // return a correct size so that the next addr + size below gives us a | |
| 881 // valid block boundary. [See for instance, | |
| 882 // ScanMarkedObjectsAgainCarefullyClosure::do_object_careful() | |
| 883 // in ConcurrentMarkSweepGeneration.cpp.] | |
| 884 HeapWord* | |
| 885 CompactibleFreeListSpace::object_iterate_careful(ObjectClosureCareful* cl) { | |
| 886 assert_lock_strong(freelistLock()); | |
| 887 HeapWord *addr, *last; | |
| 888 size_t size; | |
| 889 for (addr = bottom(), last = end(); | |
| 890 addr < last; addr += size) { | |
| 891 FreeChunk* fc = (FreeChunk*)addr; | |
| 892 if (fc->isFree()) { | |
| 893 // Since we hold the free list lock, which protects direct | |
| 894 // allocation in this generation by mutators, a free object | |
| 895 // will remain free throughout this iteration code. | |
| 896 size = fc->size(); | |
| 897 } else { | |
| 898 // Note that the object need not necessarily be initialized, | |
| 899 // because (for instance) the free list lock does NOT protect | |
| 900 // object initialization. The closure application below must | |
| 901 // therefore be correct in the face of uninitialized objects. | |
| 902 size = cl->do_object_careful(oop(addr)); | |
| 903 if (size == 0) { | |
| 904 // An unparsable object found. Signal early termination. | |
| 905 return addr; | |
| 906 } | |
| 907 } | |
| 908 } | |
| 909 return NULL; | |
| 910 } | |
| 911 | |
| 912 // Callers of this iterator beware: The closure application should | |
| 913 // be robust in the face of uninitialized objects and should (always) | |
| 914 // return a correct size so that the next addr + size below gives us a | |
| 915 // valid block boundary. [See for instance, | |
| 916 // ScanMarkedObjectsAgainCarefullyClosure::do_object_careful() | |
| 917 // in ConcurrentMarkSweepGeneration.cpp.] | |
| 918 HeapWord* | |
| 919 CompactibleFreeListSpace::object_iterate_careful_m(MemRegion mr, | |
| 920 ObjectClosureCareful* cl) { | |
| 921 assert_lock_strong(freelistLock()); | |
| 922 // Can't use used_region() below because it may not necessarily | |
| 923 // be the same as [bottom(),end()); although we could | |
| 924 // use [used_region().start(),round_to(used_region().end(),CardSize)), | |
| 925 // that appears too cumbersome, so we just do the simpler check | |
| 926 // in the assertion below. | |
| 927 assert(!mr.is_empty() && MemRegion(bottom(),end()).contains(mr), | |
| 928 "mr should be non-empty and within used space"); | |
| 929 HeapWord *addr, *end; | |
| 930 size_t size; | |
| 931 for (addr = block_start_careful(mr.start()), end = mr.end(); | |
| 932 addr < end; addr += size) { | |
| 933 FreeChunk* fc = (FreeChunk*)addr; | |
| 934 if (fc->isFree()) { | |
| 935 // Since we hold the free list lock, which protects direct | |
| 936 // allocation in this generation by mutators, a free object | |
| 937 // will remain free throughout this iteration code. | |
| 938 size = fc->size(); | |
| 939 } else { | |
| 940 // Note that the object need not necessarily be initialized, | |
| 941 // because (for instance) the free list lock does NOT protect | |
| 942 // object initialization. The closure application below must | |
| 943 // therefore be correct in the face of uninitialized objects. | |
| 944 size = cl->do_object_careful_m(oop(addr), mr); | |
| 945 if (size == 0) { | |
| 946 // An unparsable object found. Signal early termination. | |
| 947 return addr; | |
| 948 } | |
| 949 } | |
| 950 } | |
| 951 return NULL; | |
| 952 } | |
| 953 | |
| 954 | |
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955 HeapWord* CompactibleFreeListSpace::block_start_const(const void* p) const { |
| 0 | 956 NOT_PRODUCT(verify_objects_initialized()); |
| 957 return _bt.block_start(p); | |
| 958 } | |
| 959 | |
| 960 HeapWord* CompactibleFreeListSpace::block_start_careful(const void* p) const { | |
| 961 return _bt.block_start_careful(p); | |
| 962 } | |
| 963 | |
| 964 size_t CompactibleFreeListSpace::block_size(const HeapWord* p) const { | |
| 965 NOT_PRODUCT(verify_objects_initialized()); | |
| 966 // This must be volatile, or else there is a danger that the compiler | |
| 967 // will compile the code below into a sometimes-infinite loop, by keeping | |
| 968 // the value read the first time in a register. | |
| 969 while (true) { | |
| 970 // We must do this until we get a consistent view of the object. | |
| 187 | 971 if (FreeChunk::indicatesFreeChunk(p)) { |
| 972 volatile FreeChunk* fc = (volatile FreeChunk*)p; | |
| 973 size_t res = fc->size(); | |
| 974 // If the object is still a free chunk, return the size, else it | |
| 975 // has been allocated so try again. | |
| 976 if (FreeChunk::indicatesFreeChunk(p)) { | |
| 0 | 977 assert(res != 0, "Block size should not be 0"); |
| 978 return res; | |
| 979 } | |
| 187 | 980 } else { |
| 981 // must read from what 'p' points to in each loop. | |
| 982 klassOop k = ((volatile oopDesc*)p)->klass_or_null(); | |
| 983 if (k != NULL) { | |
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984 assert(k->is_oop(true /* ignore mark word */), "Should be klass oop"); |
| 187 | 985 oop o = (oop)p; |
| 986 assert(o->is_parsable(), "Should be parsable"); | |
| 987 assert(o->is_oop(true /* ignore mark word */), "Should be an oop."); | |
| 988 size_t res = o->size_given_klass(k->klass_part()); | |
| 989 res = adjustObjectSize(res); | |
| 990 assert(res != 0, "Block size should not be 0"); | |
| 991 return res; | |
| 992 } | |
| 0 | 993 } |
| 994 } | |
| 995 } | |
| 996 | |
| 997 // A variant of the above that uses the Printezis bits for | |
| 998 // unparsable but allocated objects. This avoids any possible | |
| 999 // stalls waiting for mutators to initialize objects, and is | |
| 1000 // thus potentially faster than the variant above. However, | |
| 1001 // this variant may return a zero size for a block that is | |
| 1002 // under mutation and for which a consistent size cannot be | |
| 1003 // inferred without stalling; see CMSCollector::block_size_if_printezis_bits(). | |
| 1004 size_t CompactibleFreeListSpace::block_size_no_stall(HeapWord* p, | |
| 1005 const CMSCollector* c) | |
| 1006 const { | |
| 1007 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 1008 // This must be volatile, or else there is a danger that the compiler | |
| 1009 // will compile the code below into a sometimes-infinite loop, by keeping | |
| 1010 // the value read the first time in a register. | |
| 1011 DEBUG_ONLY(uint loops = 0;) | |
| 1012 while (true) { | |
| 1013 // We must do this until we get a consistent view of the object. | |
| 187 | 1014 if (FreeChunk::indicatesFreeChunk(p)) { |
| 1015 volatile FreeChunk* fc = (volatile FreeChunk*)p; | |
| 1016 size_t res = fc->size(); | |
| 1017 if (FreeChunk::indicatesFreeChunk(p)) { | |
| 0 | 1018 assert(res != 0, "Block size should not be 0"); |
| 1019 assert(loops == 0, "Should be 0"); | |
| 1020 return res; | |
| 1021 } | |
| 1022 } else { | |
| 187 | 1023 // must read from what 'p' points to in each loop. |
| 1024 klassOop k = ((volatile oopDesc*)p)->klass_or_null(); | |
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1025 if (k != NULL && |
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1026 ((oopDesc*)p)->is_parsable() && |
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1027 ((oopDesc*)p)->is_conc_safe()) { |
| 187 | 1028 assert(k->is_oop(), "Should really be klass oop."); |
| 1029 oop o = (oop)p; | |
| 1030 assert(o->is_oop(), "Should be an oop"); | |
| 1031 size_t res = o->size_given_klass(k->klass_part()); | |
| 1032 res = adjustObjectSize(res); | |
| 1033 assert(res != 0, "Block size should not be 0"); | |
| 1034 return res; | |
| 1035 } else { | |
| 1036 return c->block_size_if_printezis_bits(p); | |
| 1037 } | |
| 0 | 1038 } |
| 1039 assert(loops == 0, "Can loop at most once"); | |
| 1040 DEBUG_ONLY(loops++;) | |
| 1041 } | |
| 1042 } | |
| 1043 | |
| 1044 size_t CompactibleFreeListSpace::block_size_nopar(const HeapWord* p) const { | |
| 1045 NOT_PRODUCT(verify_objects_initialized()); | |
| 1046 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 1047 FreeChunk* fc = (FreeChunk*)p; | |
| 1048 if (fc->isFree()) { | |
| 1049 return fc->size(); | |
| 1050 } else { | |
| 1051 // Ignore mark word because this may be a recently promoted | |
| 1052 // object whose mark word is used to chain together grey | |
| 1053 // objects (the last one would have a null value). | |
| 1054 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 1055 return adjustObjectSize(oop(p)->size()); | |
| 1056 } | |
| 1057 } | |
| 1058 | |
| 1059 // This implementation assumes that the property of "being an object" is | |
| 1060 // stable. But being a free chunk may not be (because of parallel | |
| 1061 // promotion.) | |
| 1062 bool CompactibleFreeListSpace::block_is_obj(const HeapWord* p) const { | |
| 1063 FreeChunk* fc = (FreeChunk*)p; | |
| 1064 assert(is_in_reserved(p), "Should be in space"); | |
| 1065 // When doing a mark-sweep-compact of the CMS generation, this | |
| 1066 // assertion may fail because prepare_for_compaction() uses | |
| 1067 // space that is garbage to maintain information on ranges of | |
| 1068 // live objects so that these live ranges can be moved as a whole. | |
| 1069 // Comment out this assertion until that problem can be solved | |
| 1070 // (i.e., that the block start calculation may look at objects | |
| 1071 // at address below "p" in finding the object that contains "p" | |
| 1072 // and those objects (if garbage) may have been modified to hold | |
| 1073 // live range information. | |
| 1074 // assert(ParallelGCThreads > 0 || _bt.block_start(p) == p, "Should be a block boundary"); | |
| 187 | 1075 if (FreeChunk::indicatesFreeChunk(p)) return false; |
| 1076 klassOop k = oop(p)->klass_or_null(); | |
| 0 | 1077 if (k != NULL) { |
| 1078 // Ignore mark word because it may have been used to | |
| 1079 // chain together promoted objects (the last one | |
| 1080 // would have a null value). | |
| 1081 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 1082 return true; | |
| 1083 } else { | |
| 1084 return false; // Was not an object at the start of collection. | |
| 1085 } | |
| 1086 } | |
| 1087 | |
| 1088 // Check if the object is alive. This fact is checked either by consulting | |
| 1089 // the main marking bitmap in the sweeping phase or, if it's a permanent | |
| 1090 // generation and we're not in the sweeping phase, by checking the | |
| 1091 // perm_gen_verify_bit_map where we store the "deadness" information if | |
| 1092 // we did not sweep the perm gen in the most recent previous GC cycle. | |
| 1093 bool CompactibleFreeListSpace::obj_is_alive(const HeapWord* p) const { | |
| 1094 assert (block_is_obj(p), "The address should point to an object"); | |
| 1095 | |
| 1096 // If we're sweeping, we use object liveness information from the main bit map | |
| 1097 // for both perm gen and old gen. | |
| 1098 // We don't need to lock the bitmap (live_map or dead_map below), because | |
| 1099 // EITHER we are in the middle of the sweeping phase, and the | |
| 1100 // main marking bit map (live_map below) is locked, | |
| 1101 // OR we're in other phases and perm_gen_verify_bit_map (dead_map below) | |
| 1102 // is stable, because it's mutated only in the sweeping phase. | |
| 1103 if (_collector->abstract_state() == CMSCollector::Sweeping) { | |
| 1104 CMSBitMap* live_map = _collector->markBitMap(); | |
| 1105 return live_map->isMarked((HeapWord*) p); | |
| 1106 } else { | |
| 1107 // If we're not currently sweeping and we haven't swept the perm gen in | |
| 1108 // the previous concurrent cycle then we may have dead but unswept objects | |
| 1109 // in the perm gen. In this case, we use the "deadness" information | |
| 1110 // that we had saved in perm_gen_verify_bit_map at the last sweep. | |
| 1111 if (!CMSClassUnloadingEnabled && _collector->_permGen->reserved().contains(p)) { | |
| 1112 if (_collector->verifying()) { | |
| 1113 CMSBitMap* dead_map = _collector->perm_gen_verify_bit_map(); | |
| 1114 // Object is marked in the dead_map bitmap at the previous sweep | |
| 1115 // when we know that it's dead; if the bitmap is not allocated then | |
| 1116 // the object is alive. | |
| 1117 return (dead_map->sizeInBits() == 0) // bit_map has been allocated | |
| 1118 || !dead_map->par_isMarked((HeapWord*) p); | |
| 1119 } else { | |
| 1120 return false; // We can't say for sure if it's live, so we say that it's dead. | |
| 1121 } | |
| 1122 } | |
| 1123 } | |
| 1124 return true; | |
| 1125 } | |
| 1126 | |
| 1127 bool CompactibleFreeListSpace::block_is_obj_nopar(const HeapWord* p) const { | |
| 1128 FreeChunk* fc = (FreeChunk*)p; | |
| 1129 assert(is_in_reserved(p), "Should be in space"); | |
| 1130 assert(_bt.block_start(p) == p, "Should be a block boundary"); | |
| 1131 if (!fc->isFree()) { | |
| 1132 // Ignore mark word because it may have been used to | |
| 1133 // chain together promoted objects (the last one | |
| 1134 // would have a null value). | |
| 1135 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 1136 return true; | |
| 1137 } | |
| 1138 return false; | |
| 1139 } | |
| 1140 | |
| 1141 // "MT-safe but not guaranteed MT-precise" (TM); you may get an | |
| 1142 // approximate answer if you don't hold the freelistlock when you call this. | |
| 1143 size_t CompactibleFreeListSpace::totalSizeInIndexedFreeLists() const { | |
| 1144 size_t size = 0; | |
| 1145 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 1146 debug_only( | |
| 1147 // We may be calling here without the lock in which case we | |
| 1148 // won't do this modest sanity check. | |
| 1149 if (freelistLock()->owned_by_self()) { | |
| 1150 size_t total_list_size = 0; | |
| 1151 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 1152 fc = fc->next()) { | |
| 1153 total_list_size += i; | |
| 1154 } | |
| 1155 assert(total_list_size == i * _indexedFreeList[i].count(), | |
| 1156 "Count in list is incorrect"); | |
| 1157 } | |
| 1158 ) | |
| 1159 size += i * _indexedFreeList[i].count(); | |
| 1160 } | |
| 1161 return size; | |
| 1162 } | |
| 1163 | |
| 1164 HeapWord* CompactibleFreeListSpace::par_allocate(size_t size) { | |
| 1165 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 1166 return allocate(size); | |
| 1167 } | |
| 1168 | |
| 1169 HeapWord* | |
| 1170 CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlockRemainder(size_t size) { | |
| 1171 return getChunkFromLinearAllocBlockRemainder(&_smallLinearAllocBlock, size); | |
| 1172 } | |
| 1173 | |
| 1174 HeapWord* CompactibleFreeListSpace::allocate(size_t size) { | |
| 1175 assert_lock_strong(freelistLock()); | |
| 1176 HeapWord* res = NULL; | |
| 1177 assert(size == adjustObjectSize(size), | |
| 1178 "use adjustObjectSize() before calling into allocate()"); | |
| 1179 | |
| 1180 if (_adaptive_freelists) { | |
| 1181 res = allocate_adaptive_freelists(size); | |
| 1182 } else { // non-adaptive free lists | |
| 1183 res = allocate_non_adaptive_freelists(size); | |
| 1184 } | |
| 1185 | |
| 1186 if (res != NULL) { | |
| 1187 // check that res does lie in this space! | |
| 1188 assert(is_in_reserved(res), "Not in this space!"); | |
| 1189 assert(is_aligned((void*)res), "alignment check"); | |
| 1190 | |
| 1191 FreeChunk* fc = (FreeChunk*)res; | |
| 1192 fc->markNotFree(); | |
| 1193 assert(!fc->isFree(), "shouldn't be marked free"); | |
| 187 | 1194 assert(oop(fc)->klass_or_null() == NULL, "should look uninitialized"); |
| 0 | 1195 // Verify that the block offset table shows this to |
| 1196 // be a single block, but not one which is unallocated. | |
| 1197 _bt.verify_single_block(res, size); | |
| 1198 _bt.verify_not_unallocated(res, size); | |
| 1199 // mangle a just allocated object with a distinct pattern. | |
| 1200 debug_only(fc->mangleAllocated(size)); | |
| 1201 } | |
| 1202 | |
| 1203 return res; | |
| 1204 } | |
| 1205 | |
| 1206 HeapWord* CompactibleFreeListSpace::allocate_non_adaptive_freelists(size_t size) { | |
| 1207 HeapWord* res = NULL; | |
| 1208 // try and use linear allocation for smaller blocks | |
| 1209 if (size < _smallLinearAllocBlock._allocation_size_limit) { | |
| 1210 // if successful, the following also adjusts block offset table | |
| 1211 res = getChunkFromSmallLinearAllocBlock(size); | |
| 1212 } | |
| 1213 // Else triage to indexed lists for smaller sizes | |
| 1214 if (res == NULL) { | |
| 1215 if (size < SmallForDictionary) { | |
| 1216 res = (HeapWord*) getChunkFromIndexedFreeList(size); | |
| 1217 } else { | |
| 1218 // else get it from the big dictionary; if even this doesn't | |
| 1219 // work we are out of luck. | |
| 1220 res = (HeapWord*)getChunkFromDictionaryExact(size); | |
| 1221 } | |
| 1222 } | |
| 1223 | |
| 1224 return res; | |
| 1225 } | |
| 1226 | |
| 1227 HeapWord* CompactibleFreeListSpace::allocate_adaptive_freelists(size_t size) { | |
| 1228 assert_lock_strong(freelistLock()); | |
| 1229 HeapWord* res = NULL; | |
| 1230 assert(size == adjustObjectSize(size), | |
| 1231 "use adjustObjectSize() before calling into allocate()"); | |
| 1232 | |
| 1233 // Strategy | |
| 1234 // if small | |
| 1235 // exact size from small object indexed list if small | |
| 1236 // small or large linear allocation block (linAB) as appropriate | |
| 1237 // take from lists of greater sized chunks | |
| 1238 // else | |
| 1239 // dictionary | |
| 1240 // small or large linear allocation block if it has the space | |
| 1241 // Try allocating exact size from indexTable first | |
| 1242 if (size < IndexSetSize) { | |
| 1243 res = (HeapWord*) getChunkFromIndexedFreeList(size); | |
| 1244 if(res != NULL) { | |
| 1245 assert(res != (HeapWord*)_indexedFreeList[size].head(), | |
| 1246 "Not removed from free list"); | |
| 1247 // no block offset table adjustment is necessary on blocks in | |
| 1248 // the indexed lists. | |
| 1249 | |
| 1250 // Try allocating from the small LinAB | |
| 1251 } else if (size < _smallLinearAllocBlock._allocation_size_limit && | |
| 1252 (res = getChunkFromSmallLinearAllocBlock(size)) != NULL) { | |
| 1253 // if successful, the above also adjusts block offset table | |
| 1254 // Note that this call will refill the LinAB to | |
| 1255 // satisfy the request. This is different that | |
| 1256 // evm. | |
| 1257 // Don't record chunk off a LinAB? smallSplitBirth(size); | |
| 1258 } else { | |
| 1259 // Raid the exact free lists larger than size, even if they are not | |
| 1260 // overpopulated. | |
| 1261 res = (HeapWord*) getChunkFromGreater(size); | |
| 1262 } | |
| 1263 } else { | |
| 1264 // Big objects get allocated directly from the dictionary. | |
| 1265 res = (HeapWord*) getChunkFromDictionaryExact(size); | |
| 1266 if (res == NULL) { | |
| 1267 // Try hard not to fail since an allocation failure will likely | |
| 1268 // trigger a synchronous GC. Try to get the space from the | |
| 1269 // allocation blocks. | |
| 1270 res = getChunkFromSmallLinearAllocBlockRemainder(size); | |
| 1271 } | |
| 1272 } | |
| 1273 | |
| 1274 return res; | |
| 1275 } | |
| 1276 | |
| 1277 // A worst-case estimate of the space required (in HeapWords) to expand the heap | |
| 1278 // when promoting obj. | |
| 1279 size_t CompactibleFreeListSpace::expansionSpaceRequired(size_t obj_size) const { | |
| 1280 // Depending on the object size, expansion may require refilling either a | |
| 1281 // bigLAB or a smallLAB plus refilling a PromotionInfo object. MinChunkSize | |
| 1282 // is added because the dictionary may over-allocate to avoid fragmentation. | |
| 1283 size_t space = obj_size; | |
| 1284 if (!_adaptive_freelists) { | |
| 1285 space = MAX2(space, _smallLinearAllocBlock._refillSize); | |
| 1286 } | |
| 1287 space += _promoInfo.refillSize() + 2 * MinChunkSize; | |
| 1288 return space; | |
| 1289 } | |
| 1290 | |
| 1291 FreeChunk* CompactibleFreeListSpace::getChunkFromGreater(size_t numWords) { | |
| 1292 FreeChunk* ret; | |
| 1293 | |
| 1294 assert(numWords >= MinChunkSize, "Size is less than minimum"); | |
| 1295 assert(linearAllocationWouldFail() || bestFitFirst(), | |
| 1296 "Should not be here"); | |
| 1297 | |
| 1298 size_t i; | |
| 1299 size_t currSize = numWords + MinChunkSize; | |
| 1300 assert(currSize % MinObjAlignment == 0, "currSize should be aligned"); | |
| 1301 for (i = currSize; i < IndexSetSize; i += IndexSetStride) { | |
| 1302 FreeList* fl = &_indexedFreeList[i]; | |
| 1303 if (fl->head()) { | |
| 1304 ret = getFromListGreater(fl, numWords); | |
| 1305 assert(ret == NULL || ret->isFree(), "Should be returning a free chunk"); | |
| 1306 return ret; | |
| 1307 } | |
| 1308 } | |
| 1309 | |
| 1310 currSize = MAX2((size_t)SmallForDictionary, | |
| 1311 (size_t)(numWords + MinChunkSize)); | |
| 1312 | |
| 1313 /* Try to get a chunk that satisfies request, while avoiding | |
| 1314 fragmentation that can't be handled. */ | |
| 1315 { | |
| 1316 ret = dictionary()->getChunk(currSize); | |
| 1317 if (ret != NULL) { | |
| 1318 assert(ret->size() - numWords >= MinChunkSize, | |
| 1319 "Chunk is too small"); | |
| 1320 _bt.allocated((HeapWord*)ret, ret->size()); | |
| 1321 /* Carve returned chunk. */ | |
| 1322 (void) splitChunkAndReturnRemainder(ret, numWords); | |
| 1323 /* Label this as no longer a free chunk. */ | |
| 1324 assert(ret->isFree(), "This chunk should be free"); | |
| 1325 ret->linkPrev(NULL); | |
| 1326 } | |
| 1327 assert(ret == NULL || ret->isFree(), "Should be returning a free chunk"); | |
| 1328 return ret; | |
| 1329 } | |
| 1330 ShouldNotReachHere(); | |
| 1331 } | |
| 1332 | |
| 1333 bool CompactibleFreeListSpace::verifyChunkInIndexedFreeLists(FreeChunk* fc) | |
| 1334 const { | |
| 1335 assert(fc->size() < IndexSetSize, "Size of chunk is too large"); | |
| 1336 return _indexedFreeList[fc->size()].verifyChunkInFreeLists(fc); | |
| 1337 } | |
| 1338 | |
| 1339 bool CompactibleFreeListSpace::verifyChunkInFreeLists(FreeChunk* fc) const { | |
| 1340 if (fc->size() >= IndexSetSize) { | |
| 1341 return dictionary()->verifyChunkInFreeLists(fc); | |
| 1342 } else { | |
| 1343 return verifyChunkInIndexedFreeLists(fc); | |
| 1344 } | |
| 1345 } | |
| 1346 | |
| 1347 #ifndef PRODUCT | |
| 1348 void CompactibleFreeListSpace::assert_locked() const { | |
| 1349 CMSLockVerifier::assert_locked(freelistLock(), parDictionaryAllocLock()); | |
| 1350 } | |
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1351 |
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1352 void CompactibleFreeListSpace::assert_locked(const Mutex* lock) const { |
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1353 CMSLockVerifier::assert_locked(lock); |
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1354 } |
| 0 | 1355 #endif |
| 1356 | |
| 1357 FreeChunk* CompactibleFreeListSpace::allocateScratch(size_t size) { | |
| 1358 // In the parallel case, the main thread holds the free list lock | |
| 1359 // on behalf the parallel threads. | |
| 1360 FreeChunk* fc; | |
| 1361 { | |
| 1362 // If GC is parallel, this might be called by several threads. | |
| 1363 // This should be rare enough that the locking overhead won't affect | |
| 1364 // the sequential code. | |
| 1365 MutexLockerEx x(parDictionaryAllocLock(), | |
| 1366 Mutex::_no_safepoint_check_flag); | |
| 1367 fc = getChunkFromDictionary(size); | |
| 1368 } | |
| 1369 if (fc != NULL) { | |
| 1370 fc->dontCoalesce(); | |
| 1371 assert(fc->isFree(), "Should be free, but not coalescable"); | |
| 1372 // Verify that the block offset table shows this to | |
| 1373 // be a single block, but not one which is unallocated. | |
| 1374 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 1375 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 1376 } | |
| 1377 return fc; | |
| 1378 } | |
| 1379 | |
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1380 oop CompactibleFreeListSpace::promote(oop obj, size_t obj_size) { |
| 0 | 1381 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); |
| 1382 assert_locked(); | |
| 1383 | |
| 1384 // if we are tracking promotions, then first ensure space for | |
| 1385 // promotion (including spooling space for saving header if necessary). | |
| 1386 // then allocate and copy, then track promoted info if needed. | |
| 1387 // When tracking (see PromotionInfo::track()), the mark word may | |
| 1388 // be displaced and in this case restoration of the mark word | |
| 1389 // occurs in the (oop_since_save_marks_)iterate phase. | |
| 1390 if (_promoInfo.tracking() && !_promoInfo.ensure_spooling_space()) { | |
| 1391 return NULL; | |
| 1392 } | |
| 1393 // Call the allocate(size_t, bool) form directly to avoid the | |
| 1394 // additional call through the allocate(size_t) form. Having | |
| 1395 // the compile inline the call is problematic because allocate(size_t) | |
| 1396 // is a virtual method. | |
| 1397 HeapWord* res = allocate(adjustObjectSize(obj_size)); | |
| 1398 if (res != NULL) { | |
| 1399 Copy::aligned_disjoint_words((HeapWord*)obj, res, obj_size); | |
| 1400 // if we should be tracking promotions, do so. | |
| 1401 if (_promoInfo.tracking()) { | |
| 1402 _promoInfo.track((PromotedObject*)res); | |
| 1403 } | |
| 1404 } | |
| 1405 return oop(res); | |
| 1406 } | |
| 1407 | |
| 1408 HeapWord* | |
| 1409 CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlock(size_t size) { | |
| 1410 assert_locked(); | |
| 1411 assert(size >= MinChunkSize, "minimum chunk size"); | |
| 1412 assert(size < _smallLinearAllocBlock._allocation_size_limit, | |
| 1413 "maximum from smallLinearAllocBlock"); | |
| 1414 return getChunkFromLinearAllocBlock(&_smallLinearAllocBlock, size); | |
| 1415 } | |
| 1416 | |
| 1417 HeapWord* | |
| 1418 CompactibleFreeListSpace::getChunkFromLinearAllocBlock(LinearAllocBlock *blk, | |
| 1419 size_t size) { | |
| 1420 assert_locked(); | |
| 1421 assert(size >= MinChunkSize, "too small"); | |
| 1422 HeapWord* res = NULL; | |
| 1423 // Try to do linear allocation from blk, making sure that | |
| 1424 if (blk->_word_size == 0) { | |
| 1425 // We have probably been unable to fill this either in the prologue or | |
| 1426 // when it was exhausted at the last linear allocation. Bail out until | |
| 1427 // next time. | |
| 1428 assert(blk->_ptr == NULL, "consistency check"); | |
| 1429 return NULL; | |
| 1430 } | |
| 1431 assert(blk->_word_size != 0 && blk->_ptr != NULL, "consistency check"); | |
| 1432 res = getChunkFromLinearAllocBlockRemainder(blk, size); | |
| 1433 if (res != NULL) return res; | |
| 1434 | |
| 1435 // about to exhaust this linear allocation block | |
| 1436 if (blk->_word_size == size) { // exactly satisfied | |
| 1437 res = blk->_ptr; | |
| 1438 _bt.allocated(res, blk->_word_size); | |
| 1439 } else if (size + MinChunkSize <= blk->_refillSize) { | |
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1440 size_t sz = blk->_word_size; |
| 0 | 1441 // Update _unallocated_block if the size is such that chunk would be |
| 1442 // returned to the indexed free list. All other chunks in the indexed | |
| 1443 // free lists are allocated from the dictionary so that _unallocated_block | |
| 1444 // has already been adjusted for them. Do it here so that the cost | |
| 1445 // for all chunks added back to the indexed free lists. | |
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1446 if (sz < SmallForDictionary) { |
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1447 _bt.allocated(blk->_ptr, sz); |
| 0 | 1448 } |
| 1449 // Return the chunk that isn't big enough, and then refill below. | |
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1450 addChunkToFreeLists(blk->_ptr, sz); |
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1451 splitBirth(sz); |
| 0 | 1452 // Don't keep statistics on adding back chunk from a LinAB. |
| 1453 } else { | |
| 1454 // A refilled block would not satisfy the request. | |
| 1455 return NULL; | |
| 1456 } | |
| 1457 | |
| 1458 blk->_ptr = NULL; blk->_word_size = 0; | |
| 1459 refillLinearAllocBlock(blk); | |
| 1460 assert(blk->_ptr == NULL || blk->_word_size >= size + MinChunkSize, | |
| 1461 "block was replenished"); | |
| 1462 if (res != NULL) { | |
| 1463 splitBirth(size); | |
| 1464 repairLinearAllocBlock(blk); | |
| 1465 } else if (blk->_ptr != NULL) { | |
| 1466 res = blk->_ptr; | |
| 1467 size_t blk_size = blk->_word_size; | |
| 1468 blk->_word_size -= size; | |
| 1469 blk->_ptr += size; | |
| 1470 splitBirth(size); | |
| 1471 repairLinearAllocBlock(blk); | |
| 1472 // Update BOT last so that other (parallel) GC threads see a consistent | |
| 1473 // view of the BOT and free blocks. | |
| 1474 // Above must occur before BOT is updated below. | |
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1475 OrderAccess::storestore(); |
| 0 | 1476 _bt.split_block(res, blk_size, size); // adjust block offset table |
| 1477 } | |
| 1478 return res; | |
| 1479 } | |
| 1480 | |
| 1481 HeapWord* CompactibleFreeListSpace::getChunkFromLinearAllocBlockRemainder( | |
| 1482 LinearAllocBlock* blk, | |
| 1483 size_t size) { | |
| 1484 assert_locked(); | |
| 1485 assert(size >= MinChunkSize, "too small"); | |
| 1486 | |
| 1487 HeapWord* res = NULL; | |
| 1488 // This is the common case. Keep it simple. | |
| 1489 if (blk->_word_size >= size + MinChunkSize) { | |
| 1490 assert(blk->_ptr != NULL, "consistency check"); | |
| 1491 res = blk->_ptr; | |
| 1492 // Note that the BOT is up-to-date for the linAB before allocation. It | |
| 1493 // indicates the start of the linAB. The split_block() updates the | |
| 1494 // BOT for the linAB after the allocation (indicates the start of the | |
| 1495 // next chunk to be allocated). | |
| 1496 size_t blk_size = blk->_word_size; | |
| 1497 blk->_word_size -= size; | |
| 1498 blk->_ptr += size; | |
| 1499 splitBirth(size); | |
| 1500 repairLinearAllocBlock(blk); | |
| 1501 // Update BOT last so that other (parallel) GC threads see a consistent | |
| 1502 // view of the BOT and free blocks. | |
| 1503 // Above must occur before BOT is updated below. | |
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1504 OrderAccess::storestore(); |
| 0 | 1505 _bt.split_block(res, blk_size, size); // adjust block offset table |
| 1506 _bt.allocated(res, size); | |
| 1507 } | |
| 1508 return res; | |
| 1509 } | |
| 1510 | |
| 1511 FreeChunk* | |
| 1512 CompactibleFreeListSpace::getChunkFromIndexedFreeList(size_t size) { | |
| 1513 assert_locked(); | |
| 1514 assert(size < SmallForDictionary, "just checking"); | |
| 1515 FreeChunk* res; | |
| 1516 res = _indexedFreeList[size].getChunkAtHead(); | |
| 1517 if (res == NULL) { | |
| 1518 res = getChunkFromIndexedFreeListHelper(size); | |
| 1519 } | |
| 1520 _bt.verify_not_unallocated((HeapWord*) res, size); | |
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1521 assert(res == NULL || res->size() == size, "Incorrect block size"); |
| 0 | 1522 return res; |
| 1523 } | |
| 1524 | |
| 1525 FreeChunk* | |
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1526 CompactibleFreeListSpace::getChunkFromIndexedFreeListHelper(size_t size, |
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1527 bool replenish) { |
| 0 | 1528 assert_locked(); |
| 1529 FreeChunk* fc = NULL; | |
| 1530 if (size < SmallForDictionary) { | |
| 1531 assert(_indexedFreeList[size].head() == NULL || | |
| 1532 _indexedFreeList[size].surplus() <= 0, | |
| 1533 "List for this size should be empty or under populated"); | |
| 1534 // Try best fit in exact lists before replenishing the list | |
| 1535 if (!bestFitFirst() || (fc = bestFitSmall(size)) == NULL) { | |
| 1536 // Replenish list. | |
| 1537 // | |
| 1538 // Things tried that failed. | |
| 1539 // Tried allocating out of the two LinAB's first before | |
| 1540 // replenishing lists. | |
| 1541 // Tried small linAB of size 256 (size in indexed list) | |
| 1542 // and replenishing indexed lists from the small linAB. | |
| 1543 // | |
| 1544 FreeChunk* newFc = NULL; | |
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1545 const size_t replenish_size = CMSIndexedFreeListReplenish * size; |
| 0 | 1546 if (replenish_size < SmallForDictionary) { |
| 1547 // Do not replenish from an underpopulated size. | |
| 1548 if (_indexedFreeList[replenish_size].surplus() > 0 && | |
| 1549 _indexedFreeList[replenish_size].head() != NULL) { | |
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1550 newFc = _indexedFreeList[replenish_size].getChunkAtHead(); |
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1551 } else if (bestFitFirst()) { |
| 0 | 1552 newFc = bestFitSmall(replenish_size); |
| 1553 } | |
| 1554 } | |
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1555 if (newFc == NULL && replenish_size > size) { |
| 0 | 1556 assert(CMSIndexedFreeListReplenish > 1, "ctl pt invariant"); |
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1557 newFc = getChunkFromIndexedFreeListHelper(replenish_size, false); |
| 0 | 1558 } |
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1559 // Note: The stats update re split-death of block obtained above |
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1560 // will be recorded below precisely when we know we are going to |
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1561 // be actually splitting it into more than one pieces below. |
| 0 | 1562 if (newFc != NULL) { |
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1563 if (replenish || CMSReplenishIntermediate) { |
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1564 // Replenish this list and return one block to caller. |
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1565 size_t i; |
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1566 FreeChunk *curFc, *nextFc; |
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1567 size_t num_blk = newFc->size() / size; |
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1568 assert(num_blk >= 1, "Smaller than requested?"); |
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1569 assert(newFc->size() % size == 0, "Should be integral multiple of request"); |
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1570 if (num_blk > 1) { |
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1571 // we are sure we will be splitting the block just obtained |
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1572 // into multiple pieces; record the split-death of the original |
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1573 splitDeath(replenish_size); |
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1574 } |
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1575 // carve up and link blocks 0, ..., num_blk - 2 |
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1576 // The last chunk is not added to the lists but is returned as the |
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1577 // free chunk. |
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1578 for (curFc = newFc, nextFc = (FreeChunk*)((HeapWord*)curFc + size), |
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1579 i = 0; |
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1580 i < (num_blk - 1); |
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1581 curFc = nextFc, nextFc = (FreeChunk*)((HeapWord*)nextFc + size), |
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1582 i++) { |
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1583 curFc->setSize(size); |
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1584 // Don't record this as a return in order to try and |
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1585 // determine the "returns" from a GC. |
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1586 _bt.verify_not_unallocated((HeapWord*) fc, size); |
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1587 _indexedFreeList[size].returnChunkAtTail(curFc, false); |
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1588 _bt.mark_block((HeapWord*)curFc, size); |
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1589 splitBirth(size); |
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1590 // Don't record the initial population of the indexed list |
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1591 // as a split birth. |
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1592 } |
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1593 |
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1594 // check that the arithmetic was OK above |
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1595 assert((HeapWord*)nextFc == (HeapWord*)newFc + num_blk*size, |
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1596 "inconsistency in carving newFc"); |
| 0 | 1597 curFc->setSize(size); |
| 1598 _bt.mark_block((HeapWord*)curFc, size); | |
| 1599 splitBirth(size); | |
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1600 fc = curFc; |
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1601 } else { |
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1602 // Return entire block to caller |
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1603 fc = newFc; |
| 0 | 1604 } |
| 1605 } | |
| 1606 } | |
| 1607 } else { | |
| 1608 // Get a free chunk from the free chunk dictionary to be returned to | |
| 1609 // replenish the indexed free list. | |
| 1610 fc = getChunkFromDictionaryExact(size); | |
| 1611 } | |
|
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1612 // assert(fc == NULL || fc->isFree(), "Should be returning a free chunk"); |
| 0 | 1613 return fc; |
| 1614 } | |
| 1615 | |
| 1616 FreeChunk* | |
| 1617 CompactibleFreeListSpace::getChunkFromDictionary(size_t size) { | |
| 1618 assert_locked(); | |
| 1619 FreeChunk* fc = _dictionary->getChunk(size); | |
| 1620 if (fc == NULL) { | |
| 1621 return NULL; | |
| 1622 } | |
| 1623 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1624 if (fc->size() >= size + MinChunkSize) { | |
| 1625 fc = splitChunkAndReturnRemainder(fc, size); | |
| 1626 } | |
| 1627 assert(fc->size() >= size, "chunk too small"); | |
| 1628 assert(fc->size() < size + MinChunkSize, "chunk too big"); | |
| 1629 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 1630 return fc; | |
| 1631 } | |
| 1632 | |
| 1633 FreeChunk* | |
| 1634 CompactibleFreeListSpace::getChunkFromDictionaryExact(size_t size) { | |
| 1635 assert_locked(); | |
| 1636 FreeChunk* fc = _dictionary->getChunk(size); | |
| 1637 if (fc == NULL) { | |
| 1638 return fc; | |
| 1639 } | |
| 1640 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1641 if (fc->size() == size) { | |
| 1642 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1643 return fc; | |
| 1644 } | |
| 1645 assert(fc->size() > size, "getChunk() guarantee"); | |
| 1646 if (fc->size() < size + MinChunkSize) { | |
| 1647 // Return the chunk to the dictionary and go get a bigger one. | |
| 1648 returnChunkToDictionary(fc); | |
| 1649 fc = _dictionary->getChunk(size + MinChunkSize); | |
| 1650 if (fc == NULL) { | |
| 1651 return NULL; | |
| 1652 } | |
| 1653 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1654 } | |
| 1655 assert(fc->size() >= size + MinChunkSize, "tautology"); | |
| 1656 fc = splitChunkAndReturnRemainder(fc, size); | |
| 1657 assert(fc->size() == size, "chunk is wrong size"); | |
| 1658 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1659 return fc; | |
| 1660 } | |
| 1661 | |
| 1662 void | |
| 1663 CompactibleFreeListSpace::returnChunkToDictionary(FreeChunk* chunk) { | |
| 1664 assert_locked(); | |
| 1665 | |
| 1666 size_t size = chunk->size(); | |
| 1667 _bt.verify_single_block((HeapWord*)chunk, size); | |
| 1668 // adjust _unallocated_block downward, as necessary | |
| 1669 _bt.freed((HeapWord*)chunk, size); | |
| 1670 _dictionary->returnChunk(chunk); | |
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1671 #ifndef PRODUCT |
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1672 if (CMSCollector::abstract_state() != CMSCollector::Sweeping) { |
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1673 TreeChunk::as_TreeChunk(chunk)->list()->verify_stats(); |
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1674 } |
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1675 #endif // PRODUCT |
| 0 | 1676 } |
| 1677 | |
| 1678 void | |
| 1679 CompactibleFreeListSpace::returnChunkToFreeList(FreeChunk* fc) { | |
| 1680 assert_locked(); | |
| 1681 size_t size = fc->size(); | |
| 1682 _bt.verify_single_block((HeapWord*) fc, size); | |
| 1683 _bt.verify_not_unallocated((HeapWord*) fc, size); | |
| 1684 if (_adaptive_freelists) { | |
| 1685 _indexedFreeList[size].returnChunkAtTail(fc); | |
| 1686 } else { | |
| 1687 _indexedFreeList[size].returnChunkAtHead(fc); | |
| 1688 } | |
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1689 #ifndef PRODUCT |
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1690 if (CMSCollector::abstract_state() != CMSCollector::Sweeping) { |
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1691 _indexedFreeList[size].verify_stats(); |
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1692 } |
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1693 #endif // PRODUCT |
| 0 | 1694 } |
| 1695 | |
| 1696 // Add chunk to end of last block -- if it's the largest | |
| 1697 // block -- and update BOT and census data. We would | |
| 1698 // of course have preferred to coalesce it with the | |
| 1699 // last block, but it's currently less expensive to find the | |
| 1700 // largest block than it is to find the last. | |
| 1701 void | |
| 1702 CompactibleFreeListSpace::addChunkToFreeListsAtEndRecordingStats( | |
| 1703 HeapWord* chunk, size_t size) { | |
| 1704 // check that the chunk does lie in this space! | |
| 1705 assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!"); | |
| 1706 // One of the parallel gc task threads may be here | |
| 1707 // whilst others are allocating. | |
| 1708 Mutex* lock = NULL; | |
| 1709 if (ParallelGCThreads != 0) { | |
| 1710 lock = &_parDictionaryAllocLock; | |
| 1711 } | |
| 1712 FreeChunk* ec; | |
| 1713 { | |
| 1714 MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag); | |
| 1715 ec = dictionary()->findLargestDict(); // get largest block | |
| 1716 if (ec != NULL && ec->end() == chunk) { | |
| 1717 // It's a coterminal block - we can coalesce. | |
| 1718 size_t old_size = ec->size(); | |
| 1719 coalDeath(old_size); | |
| 1720 removeChunkFromDictionary(ec); | |
| 1721 size += old_size; | |
| 1722 } else { | |
| 1723 ec = (FreeChunk*)chunk; | |
| 1724 } | |
| 1725 } | |
| 1726 ec->setSize(size); | |
| 1727 debug_only(ec->mangleFreed(size)); | |
| 1728 if (size < SmallForDictionary) { | |
| 1729 lock = _indexedFreeListParLocks[size]; | |
| 1730 } | |
| 1731 MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag); | |
| 1732 addChunkAndRepairOffsetTable((HeapWord*)ec, size, true); | |
| 1733 // record the birth under the lock since the recording involves | |
| 1734 // manipulation of the list on which the chunk lives and | |
| 1735 // if the chunk is allocated and is the last on the list, | |
| 1736 // the list can go away. | |
| 1737 coalBirth(size); | |
| 1738 } | |
| 1739 | |
| 1740 void | |
| 1741 CompactibleFreeListSpace::addChunkToFreeLists(HeapWord* chunk, | |
| 1742 size_t size) { | |
| 1743 // check that the chunk does lie in this space! | |
| 1744 assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!"); | |
| 1745 assert_locked(); | |
| 1746 _bt.verify_single_block(chunk, size); | |
| 1747 | |
| 1748 FreeChunk* fc = (FreeChunk*) chunk; | |
| 1749 fc->setSize(size); | |
| 1750 debug_only(fc->mangleFreed(size)); | |
| 1751 if (size < SmallForDictionary) { | |
| 1752 returnChunkToFreeList(fc); | |
| 1753 } else { | |
| 1754 returnChunkToDictionary(fc); | |
| 1755 } | |
| 1756 } | |
| 1757 | |
| 1758 void | |
| 1759 CompactibleFreeListSpace::addChunkAndRepairOffsetTable(HeapWord* chunk, | |
| 1760 size_t size, bool coalesced) { | |
| 1761 assert_locked(); | |
| 1762 assert(chunk != NULL, "null chunk"); | |
| 1763 if (coalesced) { | |
| 1764 // repair BOT | |
| 1765 _bt.single_block(chunk, size); | |
| 1766 } | |
| 1767 addChunkToFreeLists(chunk, size); | |
| 1768 } | |
| 1769 | |
| 1770 // We _must_ find the purported chunk on our free lists; | |
| 1771 // we assert if we don't. | |
| 1772 void | |
| 1773 CompactibleFreeListSpace::removeFreeChunkFromFreeLists(FreeChunk* fc) { | |
| 1774 size_t size = fc->size(); | |
| 1775 assert_locked(); | |
| 1776 debug_only(verifyFreeLists()); | |
| 1777 if (size < SmallForDictionary) { | |
| 1778 removeChunkFromIndexedFreeList(fc); | |
| 1779 } else { | |
| 1780 removeChunkFromDictionary(fc); | |
| 1781 } | |
| 1782 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1783 debug_only(verifyFreeLists()); | |
| 1784 } | |
| 1785 | |
| 1786 void | |
| 1787 CompactibleFreeListSpace::removeChunkFromDictionary(FreeChunk* fc) { | |
| 1788 size_t size = fc->size(); | |
| 1789 assert_locked(); | |
| 1790 assert(fc != NULL, "null chunk"); | |
| 1791 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1792 _dictionary->removeChunk(fc); | |
| 1793 // adjust _unallocated_block upward, as necessary | |
| 1794 _bt.allocated((HeapWord*)fc, size); | |
| 1795 } | |
| 1796 | |
| 1797 void | |
| 1798 CompactibleFreeListSpace::removeChunkFromIndexedFreeList(FreeChunk* fc) { | |
| 1799 assert_locked(); | |
| 1800 size_t size = fc->size(); | |
| 1801 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1802 NOT_PRODUCT( | |
| 1803 if (FLSVerifyIndexTable) { | |
| 1804 verifyIndexedFreeList(size); | |
| 1805 } | |
| 1806 ) | |
| 1807 _indexedFreeList[size].removeChunk(fc); | |
| 1808 debug_only(fc->clearNext()); | |
| 1809 debug_only(fc->clearPrev()); | |
| 1810 NOT_PRODUCT( | |
| 1811 if (FLSVerifyIndexTable) { | |
| 1812 verifyIndexedFreeList(size); | |
| 1813 } | |
| 1814 ) | |
| 1815 } | |
| 1816 | |
| 1817 FreeChunk* CompactibleFreeListSpace::bestFitSmall(size_t numWords) { | |
| 1818 /* A hint is the next larger size that has a surplus. | |
| 1819 Start search at a size large enough to guarantee that | |
| 1820 the excess is >= MIN_CHUNK. */ | |
| 1821 size_t start = align_object_size(numWords + MinChunkSize); | |
| 1822 if (start < IndexSetSize) { | |
| 1823 FreeList* it = _indexedFreeList; | |
| 1824 size_t hint = _indexedFreeList[start].hint(); | |
| 1825 while (hint < IndexSetSize) { | |
| 1826 assert(hint % MinObjAlignment == 0, "hint should be aligned"); | |
| 1827 FreeList *fl = &_indexedFreeList[hint]; | |
| 1828 if (fl->surplus() > 0 && fl->head() != NULL) { | |
| 1829 // Found a list with surplus, reset original hint | |
| 1830 // and split out a free chunk which is returned. | |
| 1831 _indexedFreeList[start].set_hint(hint); | |
| 1832 FreeChunk* res = getFromListGreater(fl, numWords); | |
| 1833 assert(res == NULL || res->isFree(), | |
| 1834 "Should be returning a free chunk"); | |
| 1835 return res; | |
| 1836 } | |
| 1837 hint = fl->hint(); /* keep looking */ | |
| 1838 } | |
| 1839 /* None found. */ | |
| 1840 it[start].set_hint(IndexSetSize); | |
| 1841 } | |
| 1842 return NULL; | |
| 1843 } | |
| 1844 | |
| 1845 /* Requires fl->size >= numWords + MinChunkSize */ | |
| 1846 FreeChunk* CompactibleFreeListSpace::getFromListGreater(FreeList* fl, | |
| 1847 size_t numWords) { | |
| 1848 FreeChunk *curr = fl->head(); | |
| 1849 size_t oldNumWords = curr->size(); | |
| 1850 assert(numWords >= MinChunkSize, "Word size is too small"); | |
| 1851 assert(curr != NULL, "List is empty"); | |
| 1852 assert(oldNumWords >= numWords + MinChunkSize, | |
| 1853 "Size of chunks in the list is too small"); | |
| 1854 | |
| 1855 fl->removeChunk(curr); | |
| 1856 // recorded indirectly by splitChunkAndReturnRemainder - | |
| 1857 // smallSplit(oldNumWords, numWords); | |
| 1858 FreeChunk* new_chunk = splitChunkAndReturnRemainder(curr, numWords); | |
| 1859 // Does anything have to be done for the remainder in terms of | |
| 1860 // fixing the card table? | |
| 1861 assert(new_chunk == NULL || new_chunk->isFree(), | |
| 1862 "Should be returning a free chunk"); | |
| 1863 return new_chunk; | |
| 1864 } | |
| 1865 | |
| 1866 FreeChunk* | |
| 1867 CompactibleFreeListSpace::splitChunkAndReturnRemainder(FreeChunk* chunk, | |
| 1868 size_t new_size) { | |
| 1869 assert_locked(); | |
| 1870 size_t size = chunk->size(); | |
| 1871 assert(size > new_size, "Split from a smaller block?"); | |
| 1872 assert(is_aligned(chunk), "alignment problem"); | |
| 1873 assert(size == adjustObjectSize(size), "alignment problem"); | |
| 1874 size_t rem_size = size - new_size; | |
| 1875 assert(rem_size == adjustObjectSize(rem_size), "alignment problem"); | |
| 1876 assert(rem_size >= MinChunkSize, "Free chunk smaller than minimum"); | |
| 1877 FreeChunk* ffc = (FreeChunk*)((HeapWord*)chunk + new_size); | |
| 1878 assert(is_aligned(ffc), "alignment problem"); | |
| 1879 ffc->setSize(rem_size); | |
| 1880 ffc->linkNext(NULL); | |
| 1881 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. | |
| 1882 // Above must occur before BOT is updated below. | |
| 1883 // adjust block offset table | |
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1884 OrderAccess::storestore(); |
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1885 assert(chunk->isFree() && ffc->isFree(), "Error"); |
| 0 | 1886 _bt.split_block((HeapWord*)chunk, chunk->size(), new_size); |
| 1887 if (rem_size < SmallForDictionary) { | |
| 1888 bool is_par = (SharedHeap::heap()->n_par_threads() > 0); | |
| 1889 if (is_par) _indexedFreeListParLocks[rem_size]->lock(); | |
| 1890 returnChunkToFreeList(ffc); | |
| 1891 split(size, rem_size); | |
| 1892 if (is_par) _indexedFreeListParLocks[rem_size]->unlock(); | |
| 1893 } else { | |
| 1894 returnChunkToDictionary(ffc); | |
| 1895 split(size ,rem_size); | |
| 1896 } | |
| 1897 chunk->setSize(new_size); | |
| 1898 return chunk; | |
| 1899 } | |
| 1900 | |
| 1901 void | |
| 1902 CompactibleFreeListSpace::sweep_completed() { | |
| 1903 // Now that space is probably plentiful, refill linear | |
| 1904 // allocation blocks as needed. | |
| 1905 refillLinearAllocBlocksIfNeeded(); | |
| 1906 } | |
| 1907 | |
| 1908 void | |
| 1909 CompactibleFreeListSpace::gc_prologue() { | |
| 1910 assert_locked(); | |
| 1911 if (PrintFLSStatistics != 0) { | |
| 1912 gclog_or_tty->print("Before GC:\n"); | |
| 1913 reportFreeListStatistics(); | |
| 1914 } | |
| 1915 refillLinearAllocBlocksIfNeeded(); | |
| 1916 } | |
| 1917 | |
| 1918 void | |
| 1919 CompactibleFreeListSpace::gc_epilogue() { | |
| 1920 assert_locked(); | |
| 1921 if (PrintGCDetails && Verbose && !_adaptive_freelists) { | |
| 1922 if (_smallLinearAllocBlock._word_size == 0) | |
| 1923 warning("CompactibleFreeListSpace(epilogue):: Linear allocation failure"); | |
| 1924 } | |
| 1925 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); | |
| 1926 _promoInfo.stopTrackingPromotions(); | |
| 1927 repairLinearAllocationBlocks(); | |
| 1928 // Print Space's stats | |
| 1929 if (PrintFLSStatistics != 0) { | |
| 1930 gclog_or_tty->print("After GC:\n"); | |
| 1931 reportFreeListStatistics(); | |
| 1932 } | |
| 1933 } | |
| 1934 | |
| 1935 // Iteration support, mostly delegated from a CMS generation | |
| 1936 | |
| 1937 void CompactibleFreeListSpace::save_marks() { | |
| 1938 // mark the "end" of the used space at the time of this call; | |
| 1939 // note, however, that promoted objects from this point | |
| 1940 // on are tracked in the _promoInfo below. | |
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1941 set_saved_mark_word(unallocated_block()); |
| 0 | 1942 // inform allocator that promotions should be tracked. |
| 1943 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); | |
| 1944 _promoInfo.startTrackingPromotions(); | |
| 1945 } | |
| 1946 | |
| 1947 bool CompactibleFreeListSpace::no_allocs_since_save_marks() { | |
| 1948 assert(_promoInfo.tracking(), "No preceding save_marks?"); | |
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1949 assert(SharedHeap::heap()->n_par_threads() == 0, |
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1950 "Shouldn't be called if using parallel gc."); |
| 0 | 1951 return _promoInfo.noPromotions(); |
| 1952 } | |
| 1953 | |
| 1954 #define CFLS_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ | |
| 1955 \ | |
| 1956 void CompactibleFreeListSpace:: \ | |
| 1957 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ | |
| 1958 assert(SharedHeap::heap()->n_par_threads() == 0, \ | |
| 1959 "Shouldn't be called (yet) during parallel part of gc."); \ | |
| 1960 _promoInfo.promoted_oops_iterate##nv_suffix(blk); \ | |
| 1961 /* \ | |
| 1962 * This also restores any displaced headers and removes the elements from \ | |
| 1963 * the iteration set as they are processed, so that we have a clean slate \ | |
| 1964 * at the end of the iteration. Note, thus, that if new objects are \ | |
| 1965 * promoted as a result of the iteration they are iterated over as well. \ | |
| 1966 */ \ | |
| 1967 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); \ | |
| 1968 } | |
| 1969 | |
| 1970 ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DEFN) | |
| 1971 | |
| 1972 | |
| 1973 void CompactibleFreeListSpace::object_iterate_since_last_GC(ObjectClosure* cl) { | |
| 1974 // ugghh... how would one do this efficiently for a non-contiguous space? | |
| 1975 guarantee(false, "NYI"); | |
| 1976 } | |
| 1977 | |
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1978 bool CompactibleFreeListSpace::linearAllocationWouldFail() const { |
| 0 | 1979 return _smallLinearAllocBlock._word_size == 0; |
| 1980 } | |
| 1981 | |
| 1982 void CompactibleFreeListSpace::repairLinearAllocationBlocks() { | |
| 1983 // Fix up linear allocation blocks to look like free blocks | |
| 1984 repairLinearAllocBlock(&_smallLinearAllocBlock); | |
| 1985 } | |
| 1986 | |
| 1987 void CompactibleFreeListSpace::repairLinearAllocBlock(LinearAllocBlock* blk) { | |
| 1988 assert_locked(); | |
| 1989 if (blk->_ptr != NULL) { | |
| 1990 assert(blk->_word_size != 0 && blk->_word_size >= MinChunkSize, | |
| 1991 "Minimum block size requirement"); | |
| 1992 FreeChunk* fc = (FreeChunk*)(blk->_ptr); | |
| 1993 fc->setSize(blk->_word_size); | |
| 1994 fc->linkPrev(NULL); // mark as free | |
| 1995 fc->dontCoalesce(); | |
| 1996 assert(fc->isFree(), "just marked it free"); | |
| 1997 assert(fc->cantCoalesce(), "just marked it uncoalescable"); | |
| 1998 } | |
| 1999 } | |
| 2000 | |
| 2001 void CompactibleFreeListSpace::refillLinearAllocBlocksIfNeeded() { | |
| 2002 assert_locked(); | |
| 2003 if (_smallLinearAllocBlock._ptr == NULL) { | |
| 2004 assert(_smallLinearAllocBlock._word_size == 0, | |
| 2005 "Size of linAB should be zero if the ptr is NULL"); | |
| 2006 // Reset the linAB refill and allocation size limit. | |
| 2007 _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, SmallForLinearAlloc); | |
| 2008 } | |
| 2009 refillLinearAllocBlockIfNeeded(&_smallLinearAllocBlock); | |
| 2010 } | |
| 2011 | |
| 2012 void | |
| 2013 CompactibleFreeListSpace::refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk) { | |
| 2014 assert_locked(); | |
| 2015 assert((blk->_ptr == NULL && blk->_word_size == 0) || | |
| 2016 (blk->_ptr != NULL && blk->_word_size >= MinChunkSize), | |
| 2017 "blk invariant"); | |
| 2018 if (blk->_ptr == NULL) { | |
| 2019 refillLinearAllocBlock(blk); | |
| 2020 } | |
| 2021 if (PrintMiscellaneous && Verbose) { | |
| 2022 if (blk->_word_size == 0) { | |
| 2023 warning("CompactibleFreeListSpace(prologue):: Linear allocation failure"); | |
| 2024 } | |
| 2025 } | |
| 2026 } | |
| 2027 | |
| 2028 void | |
| 2029 CompactibleFreeListSpace::refillLinearAllocBlock(LinearAllocBlock* blk) { | |
| 2030 assert_locked(); | |
| 2031 assert(blk->_word_size == 0 && blk->_ptr == NULL, | |
| 2032 "linear allocation block should be empty"); | |
| 2033 FreeChunk* fc; | |
| 2034 if (blk->_refillSize < SmallForDictionary && | |
| 2035 (fc = getChunkFromIndexedFreeList(blk->_refillSize)) != NULL) { | |
| 2036 // A linAB's strategy might be to use small sizes to reduce | |
| 2037 // fragmentation but still get the benefits of allocation from a | |
| 2038 // linAB. | |
| 2039 } else { | |
| 2040 fc = getChunkFromDictionary(blk->_refillSize); | |
| 2041 } | |
| 2042 if (fc != NULL) { | |
| 2043 blk->_ptr = (HeapWord*)fc; | |
| 2044 blk->_word_size = fc->size(); | |
| 2045 fc->dontCoalesce(); // to prevent sweeper from sweeping us up | |
| 2046 } | |
| 2047 } | |
| 2048 | |
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2049 // Support for concurrent collection policy decisions. |
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2050 bool CompactibleFreeListSpace::should_concurrent_collect() const { |
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2051 // In the future we might want to add in frgamentation stats -- |
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2052 // including erosion of the "mountain" into this decision as well. |
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2053 return !adaptive_freelists() && linearAllocationWouldFail(); |
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2054 } |
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2055 |
| 0 | 2056 // Support for compaction |
| 2057 | |
| 2058 void CompactibleFreeListSpace::prepare_for_compaction(CompactPoint* cp) { | |
| 2059 SCAN_AND_FORWARD(cp,end,block_is_obj,block_size); | |
| 2060 // prepare_for_compaction() uses the space between live objects | |
| 2061 // so that later phase can skip dead space quickly. So verification | |
| 2062 // of the free lists doesn't work after. | |
| 2063 } | |
| 2064 | |
| 2065 #define obj_size(q) adjustObjectSize(oop(q)->size()) | |
| 2066 #define adjust_obj_size(s) adjustObjectSize(s) | |
| 2067 | |
| 2068 void CompactibleFreeListSpace::adjust_pointers() { | |
| 2069 // In other versions of adjust_pointers(), a bail out | |
| 2070 // based on the amount of live data in the generation | |
| 2071 // (i.e., if 0, bail out) may be used. | |
| 2072 // Cannot test used() == 0 here because the free lists have already | |
| 2073 // been mangled by the compaction. | |
| 2074 | |
| 2075 SCAN_AND_ADJUST_POINTERS(adjust_obj_size); | |
| 2076 // See note about verification in prepare_for_compaction(). | |
| 2077 } | |
| 2078 | |
| 2079 void CompactibleFreeListSpace::compact() { | |
| 2080 SCAN_AND_COMPACT(obj_size); | |
| 2081 } | |
| 2082 | |
| 2083 // fragmentation_metric = 1 - [sum of (fbs**2) / (sum of fbs)**2] | |
| 2084 // where fbs is free block sizes | |
| 2085 double CompactibleFreeListSpace::flsFrag() const { | |
| 2086 size_t itabFree = totalSizeInIndexedFreeLists(); | |
| 2087 double frag = 0.0; | |
| 2088 size_t i; | |
| 2089 | |
| 2090 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2091 double sz = i; | |
| 2092 frag += _indexedFreeList[i].count() * (sz * sz); | |
| 2093 } | |
| 2094 | |
| 2095 double totFree = itabFree + | |
| 2096 _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())); | |
| 2097 if (totFree > 0) { | |
| 2098 frag = ((frag + _dictionary->sum_of_squared_block_sizes()) / | |
| 2099 (totFree * totFree)); | |
| 2100 frag = (double)1.0 - frag; | |
| 2101 } else { | |
| 2102 assert(frag == 0.0, "Follows from totFree == 0"); | |
| 2103 } | |
| 2104 return frag; | |
| 2105 } | |
| 2106 | |
| 2107 void CompactibleFreeListSpace::beginSweepFLCensus( | |
| 2108 float inter_sweep_current, | |
|
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2109 float inter_sweep_estimate, |
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2110 float intra_sweep_estimate) { |
| 0 | 2111 assert_locked(); |
| 2112 size_t i; | |
| 2113 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2114 FreeList* fl = &_indexedFreeList[i]; | |
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2115 if (PrintFLSStatistics > 1) { |
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2116 gclog_or_tty->print("size[%d] : ", i); |
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2117 } |
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2118 fl->compute_desired(inter_sweep_current, inter_sweep_estimate, intra_sweep_estimate); |
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2119 fl->set_coalDesired((ssize_t)((double)fl->desired() * CMSSmallCoalSurplusPercent)); |
| 0 | 2120 fl->set_beforeSweep(fl->count()); |
| 2121 fl->set_bfrSurp(fl->surplus()); | |
| 2122 } | |
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2123 _dictionary->beginSweepDictCensus(CMSLargeCoalSurplusPercent, |
| 0 | 2124 inter_sweep_current, |
|
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2125 inter_sweep_estimate, |
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2126 intra_sweep_estimate); |
| 0 | 2127 } |
| 2128 | |
| 2129 void CompactibleFreeListSpace::setFLSurplus() { | |
| 2130 assert_locked(); | |
| 2131 size_t i; | |
| 2132 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2133 FreeList *fl = &_indexedFreeList[i]; | |
| 2134 fl->set_surplus(fl->count() - | |
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2135 (ssize_t)((double)fl->desired() * CMSSmallSplitSurplusPercent)); |
| 0 | 2136 } |
| 2137 } | |
| 2138 | |
| 2139 void CompactibleFreeListSpace::setFLHints() { | |
| 2140 assert_locked(); | |
| 2141 size_t i; | |
| 2142 size_t h = IndexSetSize; | |
| 2143 for (i = IndexSetSize - 1; i != 0; i -= IndexSetStride) { | |
| 2144 FreeList *fl = &_indexedFreeList[i]; | |
| 2145 fl->set_hint(h); | |
| 2146 if (fl->surplus() > 0) { | |
| 2147 h = i; | |
| 2148 } | |
| 2149 } | |
| 2150 } | |
| 2151 | |
| 2152 void CompactibleFreeListSpace::clearFLCensus() { | |
| 2153 assert_locked(); | |
| 2154 int i; | |
| 2155 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2156 FreeList *fl = &_indexedFreeList[i]; | |
| 2157 fl->set_prevSweep(fl->count()); | |
| 2158 fl->set_coalBirths(0); | |
| 2159 fl->set_coalDeaths(0); | |
| 2160 fl->set_splitBirths(0); | |
| 2161 fl->set_splitDeaths(0); | |
| 2162 } | |
| 2163 } | |
| 2164 | |
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2165 void CompactibleFreeListSpace::endSweepFLCensus(size_t sweep_count) { |
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2166 if (PrintFLSStatistics > 0) { |
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2167 HeapWord* largestAddr = (HeapWord*) dictionary()->findLargestDict(); |
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2168 gclog_or_tty->print_cr("CMS: Large block " PTR_FORMAT, |
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2169 largestAddr); |
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2170 } |
| 0 | 2171 setFLSurplus(); |
| 2172 setFLHints(); | |
| 2173 if (PrintGC && PrintFLSCensus > 0) { | |
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2174 printFLCensus(sweep_count); |
| 0 | 2175 } |
| 2176 clearFLCensus(); | |
| 2177 assert_locked(); | |
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2178 _dictionary->endSweepDictCensus(CMSLargeSplitSurplusPercent); |
| 0 | 2179 } |
| 2180 | |
| 2181 bool CompactibleFreeListSpace::coalOverPopulated(size_t size) { | |
| 2182 if (size < SmallForDictionary) { | |
| 2183 FreeList *fl = &_indexedFreeList[size]; | |
| 2184 return (fl->coalDesired() < 0) || | |
| 2185 ((int)fl->count() > fl->coalDesired()); | |
| 2186 } else { | |
| 2187 return dictionary()->coalDictOverPopulated(size); | |
| 2188 } | |
| 2189 } | |
| 2190 | |
| 2191 void CompactibleFreeListSpace::smallCoalBirth(size_t size) { | |
| 2192 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2193 FreeList *fl = &_indexedFreeList[size]; | |
| 2194 fl->increment_coalBirths(); | |
| 2195 fl->increment_surplus(); | |
| 2196 } | |
| 2197 | |
| 2198 void CompactibleFreeListSpace::smallCoalDeath(size_t size) { | |
| 2199 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2200 FreeList *fl = &_indexedFreeList[size]; | |
| 2201 fl->increment_coalDeaths(); | |
| 2202 fl->decrement_surplus(); | |
| 2203 } | |
| 2204 | |
| 2205 void CompactibleFreeListSpace::coalBirth(size_t size) { | |
| 2206 if (size < SmallForDictionary) { | |
| 2207 smallCoalBirth(size); | |
| 2208 } else { | |
| 2209 dictionary()->dictCensusUpdate(size, | |
| 2210 false /* split */, | |
| 2211 true /* birth */); | |
| 2212 } | |
| 2213 } | |
| 2214 | |
| 2215 void CompactibleFreeListSpace::coalDeath(size_t size) { | |
| 2216 if(size < SmallForDictionary) { | |
| 2217 smallCoalDeath(size); | |
| 2218 } else { | |
| 2219 dictionary()->dictCensusUpdate(size, | |
| 2220 false /* split */, | |
| 2221 false /* birth */); | |
| 2222 } | |
| 2223 } | |
| 2224 | |
| 2225 void CompactibleFreeListSpace::smallSplitBirth(size_t size) { | |
| 2226 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2227 FreeList *fl = &_indexedFreeList[size]; | |
| 2228 fl->increment_splitBirths(); | |
| 2229 fl->increment_surplus(); | |
| 2230 } | |
| 2231 | |
| 2232 void CompactibleFreeListSpace::smallSplitDeath(size_t size) { | |
| 2233 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2234 FreeList *fl = &_indexedFreeList[size]; | |
| 2235 fl->increment_splitDeaths(); | |
| 2236 fl->decrement_surplus(); | |
| 2237 } | |
| 2238 | |
| 2239 void CompactibleFreeListSpace::splitBirth(size_t size) { | |
| 2240 if (size < SmallForDictionary) { | |
| 2241 smallSplitBirth(size); | |
| 2242 } else { | |
| 2243 dictionary()->dictCensusUpdate(size, | |
| 2244 true /* split */, | |
| 2245 true /* birth */); | |
| 2246 } | |
| 2247 } | |
| 2248 | |
| 2249 void CompactibleFreeListSpace::splitDeath(size_t size) { | |
| 2250 if (size < SmallForDictionary) { | |
| 2251 smallSplitDeath(size); | |
| 2252 } else { | |
| 2253 dictionary()->dictCensusUpdate(size, | |
| 2254 true /* split */, | |
| 2255 false /* birth */); | |
| 2256 } | |
| 2257 } | |
| 2258 | |
| 2259 void CompactibleFreeListSpace::split(size_t from, size_t to1) { | |
| 2260 size_t to2 = from - to1; | |
| 2261 splitDeath(from); | |
| 2262 splitBirth(to1); | |
| 2263 splitBirth(to2); | |
| 2264 } | |
| 2265 | |
| 2266 void CompactibleFreeListSpace::print() const { | |
|
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2267 Space::print_on(tty); |
| 0 | 2268 } |
| 2269 | |
| 2270 void CompactibleFreeListSpace::prepare_for_verify() { | |
| 2271 assert_locked(); | |
| 2272 repairLinearAllocationBlocks(); | |
| 2273 // Verify that the SpoolBlocks look like free blocks of | |
| 2274 // appropriate sizes... To be done ... | |
| 2275 } | |
| 2276 | |
| 2277 class VerifyAllBlksClosure: public BlkClosure { | |
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2278 private: |
| 0 | 2279 const CompactibleFreeListSpace* _sp; |
| 2280 const MemRegion _span; | |
|
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2281 HeapWord* _last_addr; |
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2282 size_t _last_size; |
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2283 bool _last_was_obj; |
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2284 bool _last_was_live; |
| 0 | 2285 |
| 2286 public: | |
| 2287 VerifyAllBlksClosure(const CompactibleFreeListSpace* sp, | |
|
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2288 MemRegion span) : _sp(sp), _span(span), |
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2289 _last_addr(NULL), _last_size(0), |
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2290 _last_was_obj(false), _last_was_live(false) { } |
| 0 | 2291 |
|
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2292 virtual size_t do_blk(HeapWord* addr) { |
| 0 | 2293 size_t res; |
|
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2294 bool was_obj = false; |
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2295 bool was_live = false; |
| 0 | 2296 if (_sp->block_is_obj(addr)) { |
|
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2297 was_obj = true; |
| 0 | 2298 oop p = oop(addr); |
| 2299 guarantee(p->is_oop(), "Should be an oop"); | |
| 2300 res = _sp->adjustObjectSize(p->size()); | |
| 2301 if (_sp->obj_is_alive(addr)) { | |
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2302 was_live = true; |
| 0 | 2303 p->verify(); |
| 2304 } | |
| 2305 } else { | |
| 2306 FreeChunk* fc = (FreeChunk*)addr; | |
| 2307 res = fc->size(); | |
| 2308 if (FLSVerifyLists && !fc->cantCoalesce()) { | |
| 2309 guarantee(_sp->verifyChunkInFreeLists(fc), | |
| 2310 "Chunk should be on a free list"); | |
| 2311 } | |
| 2312 } | |
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2313 if (res == 0) { |
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2314 gclog_or_tty->print_cr("Livelock: no rank reduction!"); |
|
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2315 gclog_or_tty->print_cr( |
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2316 " Current: addr = " PTR_FORMAT ", size = " SIZE_FORMAT ", obj = %s, live = %s \n" |
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2317 " Previous: addr = " PTR_FORMAT ", size = " SIZE_FORMAT ", obj = %s, live = %s \n", |
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2318 addr, res, was_obj ?"true":"false", was_live ?"true":"false", |
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2319 _last_addr, _last_size, _last_was_obj?"true":"false", _last_was_live?"true":"false"); |
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2320 _sp->print_on(gclog_or_tty); |
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2321 guarantee(false, "Seppuku!"); |
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2322 } |
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2323 _last_addr = addr; |
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2324 _last_size = res; |
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2325 _last_was_obj = was_obj; |
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2326 _last_was_live = was_live; |
| 0 | 2327 return res; |
| 2328 } | |
| 2329 }; | |
| 2330 | |
| 2331 class VerifyAllOopsClosure: public OopClosure { | |
|
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2332 private: |
| 0 | 2333 const CMSCollector* _collector; |
| 2334 const CompactibleFreeListSpace* _sp; | |
| 2335 const MemRegion _span; | |
| 2336 const bool _past_remark; | |
| 2337 const CMSBitMap* _bit_map; | |
| 2338 | |
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2339 protected: |
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2340 void do_oop(void* p, oop obj) { |
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2341 if (_span.contains(obj)) { // the interior oop points into CMS heap |
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2342 if (!_span.contains(p)) { // reference from outside CMS heap |
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2343 // Should be a valid object; the first disjunct below allows |
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2344 // us to sidestep an assertion in block_is_obj() that insists |
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2345 // that p be in _sp. Note that several generations (and spaces) |
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2346 // are spanned by _span (CMS heap) above. |
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2347 guarantee(!_sp->is_in_reserved(obj) || |
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2348 _sp->block_is_obj((HeapWord*)obj), |
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2349 "Should be an object"); |
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2350 guarantee(obj->is_oop(), "Should be an oop"); |
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2351 obj->verify(); |
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2352 if (_past_remark) { |
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2353 // Remark has been completed, the object should be marked |
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2354 _bit_map->isMarked((HeapWord*)obj); |
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2355 } |
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2356 } else { // reference within CMS heap |
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2357 if (_past_remark) { |
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2358 // Remark has been completed -- so the referent should have |
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2359 // been marked, if referring object is. |
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2360 if (_bit_map->isMarked(_collector->block_start(p))) { |
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2361 guarantee(_bit_map->isMarked((HeapWord*)obj), "Marking error?"); |
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2362 } |
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2363 } |
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2364 } |
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2365 } else if (_sp->is_in_reserved(p)) { |
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2366 // the reference is from FLS, and points out of FLS |
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2367 guarantee(obj->is_oop(), "Should be an oop"); |
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2368 obj->verify(); |
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2369 } |
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2370 } |
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2371 |
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2372 template <class T> void do_oop_work(T* p) { |
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2373 T heap_oop = oopDesc::load_heap_oop(p); |
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2374 if (!oopDesc::is_null(heap_oop)) { |
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2375 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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2376 do_oop(p, obj); |
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2377 } |
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2378 } |
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2379 |
| 0 | 2380 public: |
| 2381 VerifyAllOopsClosure(const CMSCollector* collector, | |
| 2382 const CompactibleFreeListSpace* sp, MemRegion span, | |
| 2383 bool past_remark, CMSBitMap* bit_map) : | |
| 2384 OopClosure(), _collector(collector), _sp(sp), _span(span), | |
| 2385 _past_remark(past_remark), _bit_map(bit_map) { } | |
| 2386 | |
|
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2387 virtual void do_oop(oop* p) { VerifyAllOopsClosure::do_oop_work(p); } |
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2388 virtual void do_oop(narrowOop* p) { VerifyAllOopsClosure::do_oop_work(p); } |
| 0 | 2389 }; |
| 2390 | |
| 2391 void CompactibleFreeListSpace::verify(bool ignored) const { | |
| 2392 assert_lock_strong(&_freelistLock); | |
| 2393 verify_objects_initialized(); | |
| 2394 MemRegion span = _collector->_span; | |
| 2395 bool past_remark = (_collector->abstract_state() == | |
| 2396 CMSCollector::Sweeping); | |
| 2397 | |
| 2398 ResourceMark rm; | |
| 2399 HandleMark hm; | |
| 2400 | |
| 2401 // Check integrity of CFL data structures | |
| 2402 _promoInfo.verify(); | |
| 2403 _dictionary->verify(); | |
| 2404 if (FLSVerifyIndexTable) { | |
| 2405 verifyIndexedFreeLists(); | |
| 2406 } | |
| 2407 // Check integrity of all objects and free blocks in space | |
| 2408 { | |
| 2409 VerifyAllBlksClosure cl(this, span); | |
| 2410 ((CompactibleFreeListSpace*)this)->blk_iterate(&cl); // cast off const | |
| 2411 } | |
| 2412 // Check that all references in the heap to FLS | |
| 2413 // are to valid objects in FLS or that references in | |
| 2414 // FLS are to valid objects elsewhere in the heap | |
| 2415 if (FLSVerifyAllHeapReferences) | |
| 2416 { | |
| 2417 VerifyAllOopsClosure cl(_collector, this, span, past_remark, | |
| 2418 _collector->markBitMap()); | |
| 2419 CollectedHeap* ch = Universe::heap(); | |
| 2420 ch->oop_iterate(&cl); // all oops in generations | |
| 2421 ch->permanent_oop_iterate(&cl); // all oops in perm gen | |
| 2422 } | |
| 2423 | |
| 2424 if (VerifyObjectStartArray) { | |
| 2425 // Verify the block offset table | |
| 2426 _bt.verify(); | |
| 2427 } | |
| 2428 } | |
| 2429 | |
| 2430 #ifndef PRODUCT | |
| 2431 void CompactibleFreeListSpace::verifyFreeLists() const { | |
| 2432 if (FLSVerifyLists) { | |
| 2433 _dictionary->verify(); | |
| 2434 verifyIndexedFreeLists(); | |
| 2435 } else { | |
| 2436 if (FLSVerifyDictionary) { | |
| 2437 _dictionary->verify(); | |
| 2438 } | |
| 2439 if (FLSVerifyIndexTable) { | |
| 2440 verifyIndexedFreeLists(); | |
| 2441 } | |
| 2442 } | |
| 2443 } | |
| 2444 #endif | |
| 2445 | |
| 2446 void CompactibleFreeListSpace::verifyIndexedFreeLists() const { | |
| 2447 size_t i = 0; | |
| 2448 for (; i < MinChunkSize; i++) { | |
| 2449 guarantee(_indexedFreeList[i].head() == NULL, "should be NULL"); | |
| 2450 } | |
| 2451 for (; i < IndexSetSize; i++) { | |
| 2452 verifyIndexedFreeList(i); | |
| 2453 } | |
| 2454 } | |
| 2455 | |
| 2456 void CompactibleFreeListSpace::verifyIndexedFreeList(size_t size) const { | |
|
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2457 FreeChunk* fc = _indexedFreeList[size].head(); |
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2458 FreeChunk* tail = _indexedFreeList[size].tail(); |
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2459 size_t num = _indexedFreeList[size].count(); |
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2460 size_t n = 0; |
|
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2461 guarantee((size % 2 == 0) || fc == NULL, "Odd slots should be empty"); |
|
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2462 for (; fc != NULL; fc = fc->next(), n++) { |
| 0 | 2463 guarantee(fc->size() == size, "Size inconsistency"); |
| 2464 guarantee(fc->isFree(), "!free?"); | |
| 2465 guarantee(fc->next() == NULL || fc->next()->prev() == fc, "Broken list"); | |
|
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2466 guarantee((fc->next() == NULL) == (fc == tail), "Incorrect tail"); |
| 0 | 2467 } |
|
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2468 guarantee(n == num, "Incorrect count"); |
| 0 | 2469 } |
| 2470 | |
| 2471 #ifndef PRODUCT | |
| 2472 void CompactibleFreeListSpace::checkFreeListConsistency() const { | |
| 2473 assert(_dictionary->minSize() <= IndexSetSize, | |
| 2474 "Some sizes can't be allocated without recourse to" | |
| 2475 " linear allocation buffers"); | |
| 2476 assert(MIN_TREE_CHUNK_SIZE*HeapWordSize == sizeof(TreeChunk), | |
| 2477 "else MIN_TREE_CHUNK_SIZE is wrong"); | |
| 2478 assert((IndexSetStride == 2 && IndexSetStart == 2) || | |
| 2479 (IndexSetStride == 1 && IndexSetStart == 1), "just checking"); | |
| 2480 assert((IndexSetStride != 2) || (MinChunkSize % 2 == 0), | |
| 2481 "Some for-loops may be incorrectly initialized"); | |
| 2482 assert((IndexSetStride != 2) || (IndexSetSize % 2 == 1), | |
| 2483 "For-loops that iterate over IndexSet with stride 2 may be wrong"); | |
| 2484 } | |
| 2485 #endif | |
| 2486 | |
|
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2487 void CompactibleFreeListSpace::printFLCensus(size_t sweep_count) const { |
| 0 | 2488 assert_lock_strong(&_freelistLock); |
|
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2489 FreeList total; |
|
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2490 gclog_or_tty->print("end sweep# " SIZE_FORMAT "\n", sweep_count); |
|
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|
2491 FreeList::print_labels_on(gclog_or_tty, "size"); |
| 0 | 2492 size_t totalFree = 0; |
| 2493 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2494 const FreeList *fl = &_indexedFreeList[i]; | |
|
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2495 totalFree += fl->count() * fl->size(); |
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2496 if (i % (40*IndexSetStride) == 0) { |
|
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|
2497 FreeList::print_labels_on(gclog_or_tty, "size"); |
|
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|
2498 } |
|
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|
2499 fl->print_on(gclog_or_tty); |
|
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|
2500 total.set_bfrSurp( total.bfrSurp() + fl->bfrSurp() ); |
|
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|
2501 total.set_surplus( total.surplus() + fl->surplus() ); |
|
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|
2502 total.set_desired( total.desired() + fl->desired() ); |
|
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|
2503 total.set_prevSweep( total.prevSweep() + fl->prevSweep() ); |
|
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|
2504 total.set_beforeSweep(total.beforeSweep() + fl->beforeSweep()); |
|
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|
2505 total.set_count( total.count() + fl->count() ); |
|
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|
2506 total.set_coalBirths( total.coalBirths() + fl->coalBirths() ); |
|
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|
2507 total.set_coalDeaths( total.coalDeaths() + fl->coalDeaths() ); |
|
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|
2508 total.set_splitBirths(total.splitBirths() + fl->splitBirths()); |
|
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|
2509 total.set_splitDeaths(total.splitDeaths() + fl->splitDeaths()); |
| 0 | 2510 } |
|
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|
2511 total.print_on(gclog_or_tty, "TOTAL"); |
|
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|
2512 gclog_or_tty->print_cr("Total free in indexed lists " |
|
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|
2513 SIZE_FORMAT " words", totalFree); |
| 0 | 2514 gclog_or_tty->print("growth: %8.5f deficit: %8.5f\n", |
|
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|
2515 (double)(total.splitBirths()+total.coalBirths()-total.splitDeaths()-total.coalDeaths())/ |
|
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|
2516 (total.prevSweep() != 0 ? (double)total.prevSweep() : 1.0), |
|
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|
2517 (double)(total.desired() - total.count())/(total.desired() != 0 ? (double)total.desired() : 1.0)); |
| 0 | 2518 _dictionary->printDictCensus(); |
| 2519 } | |
| 2520 | |
|
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2521 /////////////////////////////////////////////////////////////////////////// |
|
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2522 // CFLS_LAB |
|
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|
2523 /////////////////////////////////////////////////////////////////////////// |
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2524 |
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|
2525 #define VECTOR_257(x) \ |
|
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2526 /* 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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2527 { 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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|
2528 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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2529 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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|
2530 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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|
2531 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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2532 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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2533 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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|
2534 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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|
2535 x } |
|
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|
2536 |
|
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2537 // Initialize with default setting of CMSParPromoteBlocksToClaim, _not_ |
|
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|
2538 // OldPLABSize, whose static default is different; if overridden at the |
|
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|
2539 // command-line, this will get reinitialized via a call to |
|
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|
2540 // modify_initialization() below. |
|
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|
2541 AdaptiveWeightedAverage CFLS_LAB::_blocks_to_claim[] = |
|
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2542 VECTOR_257(AdaptiveWeightedAverage(OldPLABWeight, (float)CMSParPromoteBlocksToClaim)); |
|
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2543 size_t CFLS_LAB::_global_num_blocks[] = VECTOR_257(0); |
|
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2544 int CFLS_LAB::_global_num_workers[] = VECTOR_257(0); |
| 0 | 2545 |
| 2546 CFLS_LAB::CFLS_LAB(CompactibleFreeListSpace* cfls) : | |
| 2547 _cfls(cfls) | |
| 2548 { | |
|
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2549 assert(CompactibleFreeListSpace::IndexSetSize == 257, "Modify VECTOR_257() macro above"); |
| 0 | 2550 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
| 2551 i < CompactibleFreeListSpace::IndexSetSize; | |
| 2552 i += CompactibleFreeListSpace::IndexSetStride) { | |
| 2553 _indexedFreeList[i].set_size(i); | |
|
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2554 _num_blocks[i] = 0; |
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2555 } |
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2556 } |
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2557 |
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2558 static bool _CFLS_LAB_modified = false; |
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2559 |
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2560 void CFLS_LAB::modify_initialization(size_t n, unsigned wt) { |
|
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2561 assert(!_CFLS_LAB_modified, "Call only once"); |
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2562 _CFLS_LAB_modified = true; |
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2563 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
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2564 i < CompactibleFreeListSpace::IndexSetSize; |
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2565 i += CompactibleFreeListSpace::IndexSetStride) { |
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2566 _blocks_to_claim[i].modify(n, wt, true /* force */); |
| 0 | 2567 } |
| 2568 } | |
| 2569 | |
| 2570 HeapWord* CFLS_LAB::alloc(size_t word_sz) { | |
| 2571 FreeChunk* res; | |
|
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2572 assert(word_sz == _cfls->adjustObjectSize(word_sz), "Error"); |
| 0 | 2573 if (word_sz >= CompactibleFreeListSpace::IndexSetSize) { |
| 2574 // This locking manages sync with other large object allocations. | |
| 2575 MutexLockerEx x(_cfls->parDictionaryAllocLock(), | |
| 2576 Mutex::_no_safepoint_check_flag); | |
| 2577 res = _cfls->getChunkFromDictionaryExact(word_sz); | |
| 2578 if (res == NULL) return NULL; | |
| 2579 } else { | |
| 2580 FreeList* fl = &_indexedFreeList[word_sz]; | |
| 2581 if (fl->count() == 0) { | |
| 2582 // Attempt to refill this local free list. | |
|
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2583 get_from_global_pool(word_sz, fl); |
| 0 | 2584 // If it didn't work, give up. |
| 2585 if (fl->count() == 0) return NULL; | |
| 2586 } | |
| 2587 res = fl->getChunkAtHead(); | |
| 2588 assert(res != NULL, "Why was count non-zero?"); | |
| 2589 } | |
| 2590 res->markNotFree(); | |
| 2591 assert(!res->isFree(), "shouldn't be marked free"); | |
| 187 | 2592 assert(oop(res)->klass_or_null() == NULL, "should look uninitialized"); |
| 0 | 2593 // mangle a just allocated object with a distinct pattern. |
| 2594 debug_only(res->mangleAllocated(word_sz)); | |
| 2595 return (HeapWord*)res; | |
| 2596 } | |
| 2597 | |
|
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2598 // Get a chunk of blocks of the right size and update related |
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2599 // book-keeping stats |
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2600 void CFLS_LAB::get_from_global_pool(size_t word_sz, FreeList* fl) { |
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2601 // Get the #blocks we want to claim |
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2602 size_t n_blks = (size_t)_blocks_to_claim[word_sz].average(); |
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2603 assert(n_blks > 0, "Error"); |
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2604 assert(ResizePLAB || n_blks == OldPLABSize, "Error"); |
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2605 // In some cases, when the application has a phase change, |
|
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2606 // there may be a sudden and sharp shift in the object survival |
|
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2607 // profile, and updating the counts at the end of a scavenge |
|
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2608 // may not be quick enough, giving rise to large scavenge pauses |
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2609 // during these phase changes. It is beneficial to detect such |
|
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2610 // changes on-the-fly during a scavenge and avoid such a phase-change |
|
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2611 // pothole. The following code is a heuristic attempt to do that. |
|
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2612 // It is protected by a product flag until we have gained |
|
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2613 // enough experience with this heuristic and fine-tuned its behaviour. |
|
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2614 // WARNING: This might increase fragmentation if we overreact to |
|
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2615 // small spikes, so some kind of historical smoothing based on |
|
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2616 // previous experience with the greater reactivity might be useful. |
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2617 // Lacking sufficient experience, CMSOldPLABResizeQuicker is disabled by |
|
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2618 // default. |
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2619 if (ResizeOldPLAB && CMSOldPLABResizeQuicker) { |
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2620 size_t multiple = _num_blocks[word_sz]/(CMSOldPLABToleranceFactor*CMSOldPLABNumRefills*n_blks); |
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2621 n_blks += CMSOldPLABReactivityFactor*multiple*n_blks; |
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2622 n_blks = MIN2(n_blks, CMSOldPLABMax); |
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2623 } |
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2624 assert(n_blks > 0, "Error"); |
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2625 _cfls->par_get_chunk_of_blocks(word_sz, n_blks, fl); |
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2626 // Update stats table entry for this block size |
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2627 _num_blocks[word_sz] += fl->count(); |
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2628 } |
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2629 |
|
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2630 void CFLS_LAB::compute_desired_plab_size() { |
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2631 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
| 0 | 2632 i < CompactibleFreeListSpace::IndexSetSize; |
| 2633 i += CompactibleFreeListSpace::IndexSetStride) { | |
|
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2634 assert((_global_num_workers[i] == 0) == (_global_num_blocks[i] == 0), |
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2635 "Counter inconsistency"); |
|
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2636 if (_global_num_workers[i] > 0) { |
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2637 // Need to smooth wrt historical average |
|
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2638 if (ResizeOldPLAB) { |
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2639 _blocks_to_claim[i].sample( |
|
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2640 MAX2((size_t)CMSOldPLABMin, |
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2641 MIN2((size_t)CMSOldPLABMax, |
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2642 _global_num_blocks[i]/(_global_num_workers[i]*CMSOldPLABNumRefills)))); |
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2643 } |
|
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2644 // Reset counters for next round |
|
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2645 _global_num_workers[i] = 0; |
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2646 _global_num_blocks[i] = 0; |
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2647 if (PrintOldPLAB) { |
|
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|
2648 gclog_or_tty->print_cr("[%d]: %d", i, (size_t)_blocks_to_claim[i].average()); |
|
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2649 } |
| 0 | 2650 } |
| 2651 } | |
| 2652 } | |
| 2653 | |
|
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2654 void CFLS_LAB::retire(int tid) { |
|
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2655 // We run this single threaded with the world stopped; |
|
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2656 // so no need for locks and such. |
|
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|
2657 #define CFLS_LAB_PARALLEL_ACCESS 0 |
|
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|
2658 NOT_PRODUCT(Thread* t = Thread::current();) |
|
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2659 assert(Thread::current()->is_VM_thread(), "Error"); |
|
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|
2660 assert(CompactibleFreeListSpace::IndexSetStart == CompactibleFreeListSpace::IndexSetStride, |
|
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|
2661 "Will access to uninitialized slot below"); |
|
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|
2662 #if CFLS_LAB_PARALLEL_ACCESS |
|
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2663 for (size_t i = CompactibleFreeListSpace::IndexSetSize - 1; |
|
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|
2664 i > 0; |
|
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2665 i -= CompactibleFreeListSpace::IndexSetStride) { |
|
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|
2666 #else // CFLS_LAB_PARALLEL_ACCESS |
|
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|
2667 for (size_t i = CompactibleFreeListSpace::IndexSetStart; |
|
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2668 i < CompactibleFreeListSpace::IndexSetSize; |
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2669 i += CompactibleFreeListSpace::IndexSetStride) { |
|
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2670 #endif // !CFLS_LAB_PARALLEL_ACCESS |
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|
2671 assert(_num_blocks[i] >= (size_t)_indexedFreeList[i].count(), |
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2672 "Can't retire more than what we obtained"); |
|
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2673 if (_num_blocks[i] > 0) { |
|
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2674 size_t num_retire = _indexedFreeList[i].count(); |
|
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2675 assert(_num_blocks[i] > num_retire, "Should have used at least one"); |
|
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2676 { |
|
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|
2677 #if CFLS_LAB_PARALLEL_ACCESS |
|
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|
2678 MutexLockerEx x(_cfls->_indexedFreeListParLocks[i], |
|
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|
2679 Mutex::_no_safepoint_check_flag); |
|
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|
2680 #endif // CFLS_LAB_PARALLEL_ACCESS |
|
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2681 // Update globals stats for num_blocks used |
|
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2682 _global_num_blocks[i] += (_num_blocks[i] - num_retire); |
|
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|
2683 _global_num_workers[i]++; |
|
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|
2684 assert(_global_num_workers[i] <= (ssize_t)ParallelGCThreads, "Too big"); |
|
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|
2685 if (num_retire > 0) { |
|
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|
2686 _cfls->_indexedFreeList[i].prepend(&_indexedFreeList[i]); |
|
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|
2687 // Reset this list. |
|
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|
2688 _indexedFreeList[i] = FreeList(); |
|
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|
2689 _indexedFreeList[i].set_size(i); |
|
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|
2690 } |
|
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|
2691 } |
|
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2692 if (PrintOldPLAB) { |
|
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|
2693 gclog_or_tty->print_cr("%d[%d]: %d/%d/%d", |
|
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2694 tid, i, num_retire, _num_blocks[i], (size_t)_blocks_to_claim[i].average()); |
|
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2695 } |
|
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2696 // Reset stats for next round |
|
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|
2697 _num_blocks[i] = 0; |
|
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2698 } |
|
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|
2699 } |
|
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|
2700 } |
|
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2701 |
|
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2702 void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl) { |
| 0 | 2703 assert(fl->count() == 0, "Precondition."); |
| 2704 assert(word_sz < CompactibleFreeListSpace::IndexSetSize, | |
| 2705 "Precondition"); | |
| 2706 | |
|
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2707 // We'll try all multiples of word_sz in the indexed set, starting with |
|
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2708 // word_sz itself and, if CMSSplitIndexedFreeListBlocks, try larger multiples, |
|
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2709 // then try getting a big chunk and splitting it. |
|
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|
2710 { |
|
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|
2711 bool found; |
|
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|
2712 int k; |
|
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2713 size_t cur_sz; |
|
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2714 for (k = 1, cur_sz = k * word_sz, found = false; |
|
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2715 (cur_sz < CompactibleFreeListSpace::IndexSetSize) && |
|
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2716 (CMSSplitIndexedFreeListBlocks || k <= 1); |
|
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2717 k++, cur_sz = k * word_sz) { |
|
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2718 FreeList fl_for_cur_sz; // Empty. |
|
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|
2719 fl_for_cur_sz.set_size(cur_sz); |
|
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2720 { |
|
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|
2721 MutexLockerEx x(_indexedFreeListParLocks[cur_sz], |
|
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|
2722 Mutex::_no_safepoint_check_flag); |
|
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2723 FreeList* gfl = &_indexedFreeList[cur_sz]; |
|
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2724 if (gfl->count() != 0) { |
|
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|
2725 // nn is the number of chunks of size cur_sz that |
|
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|
2726 // we'd need to split k-ways each, in order to create |
|
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|
2727 // "n" chunks of size word_sz each. |
|
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2728 const size_t nn = MAX2(n/k, (size_t)1); |
|
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2729 gfl->getFirstNChunksFromList(nn, &fl_for_cur_sz); |
|
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2730 found = true; |
|
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2731 if (k > 1) { |
|
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|
2732 // Update split death stats for the cur_sz-size blocks list: |
|
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2733 // we increment the split death count by the number of blocks |
|
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2734 // we just took from the cur_sz-size blocks list and which |
|
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2735 // we will be splitting below. |
|
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|
2736 ssize_t deaths = gfl->splitDeaths() + |
|
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|
2737 fl_for_cur_sz.count(); |
|
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|
2738 gfl->set_splitDeaths(deaths); |
|
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|
2739 } |
|
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|
2740 } |
|
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|
2741 } |
|
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|
2742 // Now transfer fl_for_cur_sz to fl. Common case, we hope, is k = 1. |
|
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|
2743 if (found) { |
|
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|
2744 if (k == 1) { |
|
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|
2745 fl->prepend(&fl_for_cur_sz); |
|
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|
2746 } else { |
|
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|
2747 // Divide each block on fl_for_cur_sz up k ways. |
|
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|
2748 FreeChunk* fc; |
|
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|
2749 while ((fc = fl_for_cur_sz.getChunkAtHead()) != NULL) { |
|
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|
2750 // Must do this in reverse order, so that anybody attempting to |
|
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|
2751 // access the main chunk sees it as a single free block until we |
|
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|
2752 // change it. |
|
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|
2753 size_t fc_size = fc->size(); |
|
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|
2754 assert(fc->isFree(), "Error"); |
|
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|
2755 for (int i = k-1; i >= 0; i--) { |
|
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|
2756 FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz); |
|
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|
2757 assert((i != 0) || |
|
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|
2758 ((fc == ffc) && ffc->isFree() && |
|
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|
2759 (ffc->size() == k*word_sz) && (fc_size == word_sz)), |
|
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|
2760 "Counting error"); |
|
1145
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|
2761 ffc->setSize(word_sz); |
|
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|
2762 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. |
|
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|
2763 ffc->linkNext(NULL); |
|
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|
2764 // Above must occur before BOT is updated below. |
|
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|
2765 OrderAccess::storestore(); |
|
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|
2766 // splitting from the right, fc_size == i * word_sz |
|
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|
2767 _bt.mark_block((HeapWord*)ffc, word_sz, true /* reducing */); |
|
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|
2768 fc_size -= word_sz; |
|
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|
2769 assert(fc_size == i*word_sz, "Error"); |
|
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|
2770 _bt.verify_not_unallocated((HeapWord*)ffc, word_sz); |
|
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|
2771 _bt.verify_single_block((HeapWord*)fc, fc_size); |
|
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|
2772 _bt.verify_single_block((HeapWord*)ffc, word_sz); |
|
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|
2773 // Push this on "fl". |
|
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|
2774 fl->returnChunkAtHead(ffc); |
|
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|
2775 } |
|
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|
2776 // TRAP |
|
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|
2777 assert(fl->tail()->next() == NULL, "List invariant."); |
|
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|
2778 } |
|
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|
2779 } |
|
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|
2780 // Update birth stats for this block size. |
|
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|
2781 size_t num = fl->count(); |
|
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|
2782 MutexLockerEx x(_indexedFreeListParLocks[word_sz], |
|
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|
2783 Mutex::_no_safepoint_check_flag); |
|
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|
2784 ssize_t births = _indexedFreeList[word_sz].splitBirths() + num; |
|
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|
2785 _indexedFreeList[word_sz].set_splitBirths(births); |
|
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|
2786 return; |
| 0 | 2787 } |
| 2788 } | |
| 2789 } | |
| 2790 // Otherwise, we'll split a block from the dictionary. | |
| 2791 FreeChunk* fc = NULL; | |
| 2792 FreeChunk* rem_fc = NULL; | |
| 2793 size_t rem; | |
| 2794 { | |
| 2795 MutexLockerEx x(parDictionaryAllocLock(), | |
| 2796 Mutex::_no_safepoint_check_flag); | |
| 2797 while (n > 0) { | |
| 2798 fc = dictionary()->getChunk(MAX2(n * word_sz, | |
| 2799 _dictionary->minSize()), | |
| 2800 FreeBlockDictionary::atLeast); | |
| 2801 if (fc != NULL) { | |
|
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|
2802 _bt.allocated((HeapWord*)fc, fc->size(), true /* reducing */); // update _unallocated_blk |
| 0 | 2803 dictionary()->dictCensusUpdate(fc->size(), |
| 2804 true /*split*/, | |
| 2805 false /*birth*/); | |
| 2806 break; | |
| 2807 } else { | |
| 2808 n--; | |
| 2809 } | |
| 2810 } | |
| 2811 if (fc == NULL) return; | |
|
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|
2812 // Otherwise, split up that block. |
|
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2813 assert((ssize_t)n >= 1, "Control point invariant"); |
|
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|
2814 assert(fc->isFree(), "Error: should be a free block"); |
|
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|
2815 _bt.verify_single_block((HeapWord*)fc, fc->size()); |
|
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2816 const size_t nn = fc->size() / word_sz; |
| 0 | 2817 n = MIN2(nn, n); |
|
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|
2818 assert((ssize_t)n >= 1, "Control point invariant"); |
| 0 | 2819 rem = fc->size() - n * word_sz; |
| 2820 // If there is a remainder, and it's too small, allocate one fewer. | |
| 2821 if (rem > 0 && rem < MinChunkSize) { | |
| 2822 n--; rem += word_sz; | |
| 2823 } | |
|
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|
2824 // Note that at this point we may have n == 0. |
|
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|
2825 assert((ssize_t)n >= 0, "Control point invariant"); |
|
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jmasa
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|
2826 |
|
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|
2827 // If n is 0, the chunk fc that was found is not large |
|
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|
2828 // enough to leave a viable remainder. We are unable to |
|
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|
2829 // allocate even one block. Return fc to the |
|
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|
2830 // dictionary and return, leaving "fl" empty. |
|
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|
2831 if (n == 0) { |
|
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|
2832 returnChunkToDictionary(fc); |
|
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|
2833 assert(fl->count() == 0, "We never allocated any blocks"); |
|
1148
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|
2834 return; |
|
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|
2835 } |
|
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|
2836 |
| 0 | 2837 // First return the remainder, if any. |
| 2838 // Note that we hold the lock until we decide if we're going to give | |
|
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|
2839 // back the remainder to the dictionary, since a concurrent allocation |
| 0 | 2840 // may otherwise see the heap as empty. (We're willing to take that |
| 2841 // hit if the block is a small block.) | |
| 2842 if (rem > 0) { | |
| 2843 size_t prefix_size = n * word_sz; | |
| 2844 rem_fc = (FreeChunk*)((HeapWord*)fc + prefix_size); | |
| 2845 rem_fc->setSize(rem); | |
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2846 rem_fc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. |
| 0 | 2847 rem_fc->linkNext(NULL); |
| 2848 // Above must occur before BOT is updated below. | |
|
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2849 assert((ssize_t)n > 0 && prefix_size > 0 && rem_fc > fc, "Error"); |
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2850 OrderAccess::storestore(); |
| 0 | 2851 _bt.split_block((HeapWord*)fc, fc->size(), prefix_size); |
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2852 assert(fc->isFree(), "Error"); |
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2853 fc->setSize(prefix_size); |
| 0 | 2854 if (rem >= IndexSetSize) { |
| 2855 returnChunkToDictionary(rem_fc); | |
|
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2856 dictionary()->dictCensusUpdate(rem, true /*split*/, true /*birth*/); |
| 0 | 2857 rem_fc = NULL; |
| 2858 } | |
| 2859 // Otherwise, return it to the small list below. | |
| 2860 } | |
| 2861 } | |
| 2862 if (rem_fc != NULL) { | |
| 2863 MutexLockerEx x(_indexedFreeListParLocks[rem], | |
| 2864 Mutex::_no_safepoint_check_flag); | |
| 2865 _bt.verify_not_unallocated((HeapWord*)rem_fc, rem_fc->size()); | |
| 2866 _indexedFreeList[rem].returnChunkAtHead(rem_fc); | |
| 2867 smallSplitBirth(rem); | |
| 2868 } | |
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2869 assert((ssize_t)n > 0 && fc != NULL, "Consistency"); |
| 0 | 2870 // Now do the splitting up. |
| 2871 // Must do this in reverse order, so that anybody attempting to | |
| 2872 // access the main chunk sees it as a single free block until we | |
| 2873 // change it. | |
| 2874 size_t fc_size = n * word_sz; | |
| 2875 // All but first chunk in this loop | |
| 2876 for (ssize_t i = n-1; i > 0; i--) { | |
| 2877 FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz); | |
| 2878 ffc->setSize(word_sz); | |
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2879 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. |
| 0 | 2880 ffc->linkNext(NULL); |
| 2881 // Above must occur before BOT is updated below. | |
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2882 OrderAccess::storestore(); |
| 0 | 2883 // splitting from the right, fc_size == (n - i + 1) * wordsize |
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2884 _bt.mark_block((HeapWord*)ffc, word_sz, true /* reducing */); |
| 0 | 2885 fc_size -= word_sz; |
| 2886 _bt.verify_not_unallocated((HeapWord*)ffc, ffc->size()); | |
| 2887 _bt.verify_single_block((HeapWord*)ffc, ffc->size()); | |
| 2888 _bt.verify_single_block((HeapWord*)fc, fc_size); | |
| 2889 // Push this on "fl". | |
| 2890 fl->returnChunkAtHead(ffc); | |
| 2891 } | |
| 2892 // First chunk | |
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2893 assert(fc->isFree() && fc->size() == n*word_sz, "Error: should still be a free block"); |
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2894 // The blocks above should show their new sizes before the first block below |
| 0 | 2895 fc->setSize(word_sz); |
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2896 fc->linkPrev(NULL); // idempotent wrt free-ness, see assert above |
| 0 | 2897 fc->linkNext(NULL); |
| 2898 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 2899 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 2900 fl->returnChunkAtHead(fc); | |
| 2901 | |
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2902 assert((ssize_t)n > 0 && (ssize_t)n == fl->count(), "Incorrect number of blocks"); |
| 0 | 2903 { |
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2904 // Update the stats for this block size. |
| 0 | 2905 MutexLockerEx x(_indexedFreeListParLocks[word_sz], |
| 2906 Mutex::_no_safepoint_check_flag); | |
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2907 const ssize_t births = _indexedFreeList[word_sz].splitBirths() + n; |
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2908 _indexedFreeList[word_sz].set_splitBirths(births); |
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2909 // ssize_t new_surplus = _indexedFreeList[word_sz].surplus() + n; |
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2910 // _indexedFreeList[word_sz].set_surplus(new_surplus); |
| 0 | 2911 } |
| 2912 | |
| 2913 // TRAP | |
| 2914 assert(fl->tail()->next() == NULL, "List invariant."); | |
| 2915 } | |
| 2916 | |
| 2917 // Set up the space's par_seq_tasks structure for work claiming | |
| 2918 // for parallel rescan. See CMSParRemarkTask where this is currently used. | |
| 2919 // XXX Need to suitably abstract and generalize this and the next | |
| 2920 // method into one. | |
| 2921 void | |
| 2922 CompactibleFreeListSpace:: | |
| 2923 initialize_sequential_subtasks_for_rescan(int n_threads) { | |
| 2924 // The "size" of each task is fixed according to rescan_task_size. | |
| 2925 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 2926 const size_t task_size = rescan_task_size(); | |
| 2927 size_t n_tasks = (used_region().word_size() + task_size - 1)/task_size; | |
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2928 assert((n_tasks == 0) == used_region().is_empty(), "n_tasks incorrect"); |
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2929 assert(n_tasks == 0 || |
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2930 ((used_region().start() + (n_tasks - 1)*task_size < used_region().end()) && |
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2931 (used_region().start() + n_tasks*task_size >= used_region().end())), |
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2932 "n_tasks calculation incorrect"); |
| 0 | 2933 SequentialSubTasksDone* pst = conc_par_seq_tasks(); |
| 2934 assert(!pst->valid(), "Clobbering existing data?"); | |
| 2935 pst->set_par_threads(n_threads); | |
| 2936 pst->set_n_tasks((int)n_tasks); | |
| 2937 } | |
| 2938 | |
| 2939 // Set up the space's par_seq_tasks structure for work claiming | |
| 2940 // for parallel concurrent marking. See CMSConcMarkTask where this is currently used. | |
| 2941 void | |
| 2942 CompactibleFreeListSpace:: | |
| 2943 initialize_sequential_subtasks_for_marking(int n_threads, | |
| 2944 HeapWord* low) { | |
| 2945 // The "size" of each task is fixed according to rescan_task_size. | |
| 2946 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 2947 const size_t task_size = marking_task_size(); | |
| 2948 assert(task_size > CardTableModRefBS::card_size_in_words && | |
| 2949 (task_size % CardTableModRefBS::card_size_in_words == 0), | |
| 2950 "Otherwise arithmetic below would be incorrect"); | |
| 2951 MemRegion span = _gen->reserved(); | |
| 2952 if (low != NULL) { | |
| 2953 if (span.contains(low)) { | |
| 2954 // Align low down to a card boundary so that | |
| 2955 // we can use block_offset_careful() on span boundaries. | |
| 2956 HeapWord* aligned_low = (HeapWord*)align_size_down((uintptr_t)low, | |
| 2957 CardTableModRefBS::card_size); | |
| 2958 // Clip span prefix at aligned_low | |
| 2959 span = span.intersection(MemRegion(aligned_low, span.end())); | |
| 2960 } else if (low > span.end()) { | |
| 2961 span = MemRegion(low, low); // Null region | |
| 2962 } // else use entire span | |
| 2963 } | |
| 2964 assert(span.is_empty() || | |
| 2965 ((uintptr_t)span.start() % CardTableModRefBS::card_size == 0), | |
| 2966 "span should start at a card boundary"); | |
| 2967 size_t n_tasks = (span.word_size() + task_size - 1)/task_size; | |
| 2968 assert((n_tasks == 0) == span.is_empty(), "Inconsistency"); | |
| 2969 assert(n_tasks == 0 || | |
| 2970 ((span.start() + (n_tasks - 1)*task_size < span.end()) && | |
| 2971 (span.start() + n_tasks*task_size >= span.end())), | |
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2972 "n_tasks calculation incorrect"); |
| 0 | 2973 SequentialSubTasksDone* pst = conc_par_seq_tasks(); |
| 2974 assert(!pst->valid(), "Clobbering existing data?"); | |
| 2975 pst->set_par_threads(n_threads); | |
| 2976 pst->set_n_tasks((int)n_tasks); | |
| 2977 } |