Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp @ 340:ebeb6490b814
6722116: CMS: Incorrect overflow handling when using parallel concurrent marking
Summary: Fixed CMSConcMarkingTask::reset() to store the restart address upon a marking stack overflow and to use it as the base, suitably aligned, for restarting the scan in CMSConcMarkingTask::do_scan_and_mark().
Reviewed-by: jcoomes, tonyp
| author | ysr |
|---|---|
| date | Tue, 26 Aug 2008 14:54:48 -0700 |
| parents | 850fdf70db2b |
| children | 5d254928c888 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 196 | 2 * Copyright 2001-2008 Sun Microsystems, Inc. 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 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 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 | |
| 35 // Constructor | |
| 36 CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs, | |
| 37 MemRegion mr, bool use_adaptive_freelists, | |
| 38 FreeBlockDictionary::DictionaryChoice dictionaryChoice) : | |
| 39 _dictionaryChoice(dictionaryChoice), | |
| 40 _adaptive_freelists(use_adaptive_freelists), | |
| 41 _bt(bs, mr), | |
| 42 // free list locks are in the range of values taken by _lockRank | |
| 43 // This range currently is [_leaf+2, _leaf+3] | |
| 44 // Note: this requires that CFLspace c'tors | |
| 45 // are called serially in the order in which the locks are | |
| 46 // are acquired in the program text. This is true today. | |
| 47 _freelistLock(_lockRank--, "CompactibleFreeListSpace._lock", true), | |
| 48 _parDictionaryAllocLock(Mutex::leaf - 1, // == rank(ExpandHeap_lock) - 1 | |
| 49 "CompactibleFreeListSpace._dict_par_lock", true), | |
| 50 _rescan_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord * | |
| 51 CMSRescanMultiple), | |
| 52 _marking_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord * | |
| 53 CMSConcMarkMultiple), | |
| 54 _collector(NULL) | |
| 55 { | |
| 56 _bt.set_space(this); | |
|
263
12eea04c8b06
6672698: mangle_unused_area() should not remangle the entire heap at each collection.
jmasa
parents:
187
diff
changeset
|
57 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); |
| 0 | 58 // We have all of "mr", all of which we place in the dictionary |
| 59 // as one big chunk. We'll need to decide here which of several | |
| 60 // possible alternative dictionary implementations to use. For | |
| 61 // now the choice is easy, since we have only one working | |
| 62 // implementation, namely, the simple binary tree (splaying | |
| 63 // temporarily disabled). | |
| 64 switch (dictionaryChoice) { | |
| 65 case FreeBlockDictionary::dictionaryBinaryTree: | |
| 66 _dictionary = new BinaryTreeDictionary(mr); | |
| 67 break; | |
| 68 case FreeBlockDictionary::dictionarySplayTree: | |
| 69 case FreeBlockDictionary::dictionarySkipList: | |
| 70 default: | |
| 71 warning("dictionaryChoice: selected option not understood; using" | |
| 72 " default BinaryTreeDictionary implementation instead."); | |
| 73 _dictionary = new BinaryTreeDictionary(mr); | |
| 74 break; | |
| 75 } | |
| 76 splitBirth(mr.word_size()); | |
| 77 assert(_dictionary != NULL, "CMS dictionary initialization"); | |
| 78 // The indexed free lists are initially all empty and are lazily | |
| 79 // filled in on demand. Initialize the array elements to NULL. | |
| 80 initializeIndexedFreeListArray(); | |
| 81 | |
| 82 // Not using adaptive free lists assumes that allocation is first | |
| 83 // from the linAB's. Also a cms perm gen which can be compacted | |
| 84 // has to have the klass's klassKlass allocated at a lower | |
| 85 // address in the heap than the klass so that the klassKlass is | |
| 86 // moved to its new location before the klass is moved. | |
| 87 // Set the _refillSize for the linear allocation blocks | |
| 88 if (!use_adaptive_freelists) { | |
| 89 FreeChunk* fc = _dictionary->getChunk(mr.word_size()); | |
| 90 // The small linAB initially has all the space and will allocate | |
| 91 // a chunk of any size. | |
| 92 HeapWord* addr = (HeapWord*) fc; | |
| 93 _smallLinearAllocBlock.set(addr, fc->size() , | |
| 94 1024*SmallForLinearAlloc, fc->size()); | |
| 95 // Note that _unallocated_block is not updated here. | |
| 96 // Allocations from the linear allocation block should | |
| 97 // update it. | |
| 98 } else { | |
| 99 _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, | |
| 100 SmallForLinearAlloc); | |
| 101 } | |
| 102 // CMSIndexedFreeListReplenish should be at least 1 | |
| 103 CMSIndexedFreeListReplenish = MAX2((uintx)1, CMSIndexedFreeListReplenish); | |
| 104 _promoInfo.setSpace(this); | |
| 105 if (UseCMSBestFit) { | |
| 106 _fitStrategy = FreeBlockBestFitFirst; | |
| 107 } else { | |
| 108 _fitStrategy = FreeBlockStrategyNone; | |
| 109 } | |
| 110 checkFreeListConsistency(); | |
| 111 | |
| 112 // Initialize locks for parallel case. | |
| 113 if (ParallelGCThreads > 0) { | |
| 114 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 115 _indexedFreeListParLocks[i] = new Mutex(Mutex::leaf - 1, // == ExpandHeap_lock - 1 | |
| 116 "a freelist par lock", | |
| 117 true); | |
| 118 if (_indexedFreeListParLocks[i] == NULL) | |
| 119 vm_exit_during_initialization("Could not allocate a par lock"); | |
| 120 DEBUG_ONLY( | |
| 121 _indexedFreeList[i].set_protecting_lock(_indexedFreeListParLocks[i]); | |
| 122 ) | |
| 123 } | |
| 124 _dictionary->set_par_lock(&_parDictionaryAllocLock); | |
| 125 } | |
| 126 } | |
| 127 | |
| 128 // Like CompactibleSpace forward() but always calls cross_threshold() to | |
| 129 // update the block offset table. Removed initialize_threshold call because | |
| 130 // CFLS does not use a block offset array for contiguous spaces. | |
| 131 HeapWord* CompactibleFreeListSpace::forward(oop q, size_t size, | |
| 132 CompactPoint* cp, HeapWord* compact_top) { | |
| 133 // q is alive | |
| 134 // First check if we should switch compaction space | |
| 135 assert(this == cp->space, "'this' should be current compaction space."); | |
| 136 size_t compaction_max_size = pointer_delta(end(), compact_top); | |
| 137 assert(adjustObjectSize(size) == cp->space->adjust_object_size_v(size), | |
| 138 "virtual adjustObjectSize_v() method is not correct"); | |
| 139 size_t adjusted_size = adjustObjectSize(size); | |
| 140 assert(compaction_max_size >= MinChunkSize || compaction_max_size == 0, | |
| 141 "no small fragments allowed"); | |
| 142 assert(minimum_free_block_size() == MinChunkSize, | |
| 143 "for de-virtualized reference below"); | |
| 144 // Can't leave a nonzero size, residual fragment smaller than MinChunkSize | |
| 145 if (adjusted_size + MinChunkSize > compaction_max_size && | |
| 146 adjusted_size != compaction_max_size) { | |
| 147 do { | |
| 148 // switch to next compaction space | |
| 149 cp->space->set_compaction_top(compact_top); | |
| 150 cp->space = cp->space->next_compaction_space(); | |
| 151 if (cp->space == NULL) { | |
| 152 cp->gen = GenCollectedHeap::heap()->prev_gen(cp->gen); | |
| 153 assert(cp->gen != NULL, "compaction must succeed"); | |
| 154 cp->space = cp->gen->first_compaction_space(); | |
| 155 assert(cp->space != NULL, "generation must have a first compaction space"); | |
| 156 } | |
| 157 compact_top = cp->space->bottom(); | |
| 158 cp->space->set_compaction_top(compact_top); | |
| 159 // The correct adjusted_size may not be the same as that for this method | |
| 160 // (i.e., cp->space may no longer be "this" so adjust the size again. | |
| 161 // Use the virtual method which is not used above to save the virtual | |
| 162 // dispatch. | |
| 163 adjusted_size = cp->space->adjust_object_size_v(size); | |
| 164 compaction_max_size = pointer_delta(cp->space->end(), compact_top); | |
| 165 assert(cp->space->minimum_free_block_size() == 0, "just checking"); | |
| 166 } while (adjusted_size > compaction_max_size); | |
| 167 } | |
| 168 | |
| 169 // store the forwarding pointer into the mark word | |
| 170 if ((HeapWord*)q != compact_top) { | |
| 171 q->forward_to(oop(compact_top)); | |
| 172 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); | |
| 173 } else { | |
| 174 // if the object isn't moving we can just set the mark to the default | |
| 175 // mark and handle it specially later on. | |
| 176 q->init_mark(); | |
| 177 assert(q->forwardee() == NULL, "should be forwarded to NULL"); | |
| 178 } | |
| 179 | |
|
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6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
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changeset
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180 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::register_live_oop(q, adjusted_size)); |
| 0 | 181 compact_top += adjusted_size; |
| 182 | |
| 183 // we need to update the offset table so that the beginnings of objects can be | |
| 184 // found during scavenge. Note that we are updating the offset table based on | |
| 185 // where the object will be once the compaction phase finishes. | |
| 186 | |
| 187 // Always call cross_threshold(). A contiguous space can only call it when | |
| 188 // the compaction_top exceeds the current threshold but not for an | |
| 189 // non-contiguous space. | |
| 190 cp->threshold = | |
| 191 cp->space->cross_threshold(compact_top - adjusted_size, compact_top); | |
| 192 return compact_top; | |
| 193 } | |
| 194 | |
| 195 // A modified copy of OffsetTableContigSpace::cross_threshold() with _offsets -> _bt | |
| 196 // and use of single_block instead of alloc_block. The name here is not really | |
| 197 // appropriate - maybe a more general name could be invented for both the | |
| 198 // contiguous and noncontiguous spaces. | |
| 199 | |
| 200 HeapWord* CompactibleFreeListSpace::cross_threshold(HeapWord* start, HeapWord* the_end) { | |
| 201 _bt.single_block(start, the_end); | |
| 202 return end(); | |
| 203 } | |
| 204 | |
| 205 // Initialize them to NULL. | |
| 206 void CompactibleFreeListSpace::initializeIndexedFreeListArray() { | |
| 207 for (size_t i = 0; i < IndexSetSize; i++) { | |
| 208 // Note that on platforms where objects are double word aligned, | |
| 209 // the odd array elements are not used. It is convenient, however, | |
| 210 // to map directly from the object size to the array element. | |
| 211 _indexedFreeList[i].reset(IndexSetSize); | |
| 212 _indexedFreeList[i].set_size(i); | |
| 213 assert(_indexedFreeList[i].count() == 0, "reset check failed"); | |
| 214 assert(_indexedFreeList[i].head() == NULL, "reset check failed"); | |
| 215 assert(_indexedFreeList[i].tail() == NULL, "reset check failed"); | |
| 216 assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed"); | |
| 217 } | |
| 218 } | |
| 219 | |
| 220 void CompactibleFreeListSpace::resetIndexedFreeListArray() { | |
| 221 for (int i = 1; i < IndexSetSize; i++) { | |
| 222 assert(_indexedFreeList[i].size() == (size_t) i, | |
| 223 "Indexed free list sizes are incorrect"); | |
| 224 _indexedFreeList[i].reset(IndexSetSize); | |
| 225 assert(_indexedFreeList[i].count() == 0, "reset check failed"); | |
| 226 assert(_indexedFreeList[i].head() == NULL, "reset check failed"); | |
| 227 assert(_indexedFreeList[i].tail() == NULL, "reset check failed"); | |
| 228 assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed"); | |
| 229 } | |
| 230 } | |
| 231 | |
| 232 void CompactibleFreeListSpace::reset(MemRegion mr) { | |
| 233 resetIndexedFreeListArray(); | |
| 234 dictionary()->reset(); | |
| 235 if (BlockOffsetArrayUseUnallocatedBlock) { | |
| 236 assert(end() == mr.end(), "We are compacting to the bottom of CMS gen"); | |
| 237 // Everything's allocated until proven otherwise. | |
| 238 _bt.set_unallocated_block(end()); | |
| 239 } | |
| 240 if (!mr.is_empty()) { | |
| 241 assert(mr.word_size() >= MinChunkSize, "Chunk size is too small"); | |
| 242 _bt.single_block(mr.start(), mr.word_size()); | |
| 243 FreeChunk* fc = (FreeChunk*) mr.start(); | |
| 244 fc->setSize(mr.word_size()); | |
| 245 if (mr.word_size() >= IndexSetSize ) { | |
| 246 returnChunkToDictionary(fc); | |
| 247 } else { | |
| 248 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 249 _indexedFreeList[mr.word_size()].returnChunkAtHead(fc); | |
| 250 } | |
| 251 } | |
| 252 _promoInfo.reset(); | |
| 253 _smallLinearAllocBlock._ptr = NULL; | |
| 254 _smallLinearAllocBlock._word_size = 0; | |
| 255 } | |
| 256 | |
| 257 void CompactibleFreeListSpace::reset_after_compaction() { | |
| 258 // Reset the space to the new reality - one free chunk. | |
| 259 MemRegion mr(compaction_top(), end()); | |
| 260 reset(mr); | |
| 261 // Now refill the linear allocation block(s) if possible. | |
| 262 if (_adaptive_freelists) { | |
| 263 refillLinearAllocBlocksIfNeeded(); | |
| 264 } else { | |
| 265 // Place as much of mr in the linAB as we can get, | |
| 266 // provided it was big enough to go into the dictionary. | |
| 267 FreeChunk* fc = dictionary()->findLargestDict(); | |
| 268 if (fc != NULL) { | |
| 269 assert(fc->size() == mr.word_size(), | |
| 270 "Why was the chunk broken up?"); | |
| 271 removeChunkFromDictionary(fc); | |
| 272 HeapWord* addr = (HeapWord*) fc; | |
| 273 _smallLinearAllocBlock.set(addr, fc->size() , | |
| 274 1024*SmallForLinearAlloc, fc->size()); | |
| 275 // Note that _unallocated_block is not updated here. | |
| 276 } | |
| 277 } | |
| 278 } | |
| 279 | |
| 280 // Walks the entire dictionary, returning a coterminal | |
| 281 // chunk, if it exists. Use with caution since it involves | |
| 282 // a potentially complete walk of a potentially large tree. | |
| 283 FreeChunk* CompactibleFreeListSpace::find_chunk_at_end() { | |
| 284 | |
| 285 assert_lock_strong(&_freelistLock); | |
| 286 | |
| 287 return dictionary()->find_chunk_ends_at(end()); | |
| 288 } | |
| 289 | |
| 290 | |
| 291 #ifndef PRODUCT | |
| 292 void CompactibleFreeListSpace::initializeIndexedFreeListArrayReturnedBytes() { | |
| 293 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 294 _indexedFreeList[i].allocation_stats()->set_returnedBytes(0); | |
| 295 } | |
| 296 } | |
| 297 | |
| 298 size_t CompactibleFreeListSpace::sumIndexedFreeListArrayReturnedBytes() { | |
| 299 size_t sum = 0; | |
| 300 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 301 sum += _indexedFreeList[i].allocation_stats()->returnedBytes(); | |
| 302 } | |
| 303 return sum; | |
| 304 } | |
| 305 | |
| 306 size_t CompactibleFreeListSpace::totalCountInIndexedFreeLists() const { | |
| 307 size_t count = 0; | |
| 308 for (int i = MinChunkSize; i < IndexSetSize; i++) { | |
| 309 debug_only( | |
| 310 ssize_t total_list_count = 0; | |
| 311 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 312 fc = fc->next()) { | |
| 313 total_list_count++; | |
| 314 } | |
| 315 assert(total_list_count == _indexedFreeList[i].count(), | |
| 316 "Count in list is incorrect"); | |
| 317 ) | |
| 318 count += _indexedFreeList[i].count(); | |
| 319 } | |
| 320 return count; | |
| 321 } | |
| 322 | |
| 323 size_t CompactibleFreeListSpace::totalCount() { | |
| 324 size_t num = totalCountInIndexedFreeLists(); | |
| 325 num += dictionary()->totalCount(); | |
| 326 if (_smallLinearAllocBlock._word_size != 0) { | |
| 327 num++; | |
| 328 } | |
| 329 return num; | |
| 330 } | |
| 331 #endif | |
| 332 | |
| 333 bool CompactibleFreeListSpace::is_free_block(const HeapWord* p) const { | |
| 334 FreeChunk* fc = (FreeChunk*) p; | |
| 335 return fc->isFree(); | |
| 336 } | |
| 337 | |
| 338 size_t CompactibleFreeListSpace::used() const { | |
| 339 return capacity() - free(); | |
| 340 } | |
| 341 | |
| 342 size_t CompactibleFreeListSpace::free() const { | |
| 343 // "MT-safe, but not MT-precise"(TM), if you will: i.e. | |
| 344 // if you do this while the structures are in flux you | |
| 345 // may get an approximate answer only; for instance | |
| 346 // because there is concurrent allocation either | |
| 347 // directly by mutators or for promotion during a GC. | |
| 348 // It's "MT-safe", however, in the sense that you are guaranteed | |
| 349 // not to crash and burn, for instance, because of walking | |
| 350 // pointers that could disappear as you were walking them. | |
| 351 // The approximation is because the various components | |
| 352 // that are read below are not read atomically (and | |
| 353 // further the computation of totalSizeInIndexedFreeLists() | |
| 354 // is itself a non-atomic computation. The normal use of | |
| 355 // this is during a resize operation at the end of GC | |
| 356 // and at that time you are guaranteed to get the | |
| 357 // correct actual value. However, for instance, this is | |
| 358 // also read completely asynchronously by the "perf-sampler" | |
| 359 // that supports jvmstat, and you are apt to see the values | |
| 360 // flicker in such cases. | |
| 361 assert(_dictionary != NULL, "No _dictionary?"); | |
| 362 return (_dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())) + | |
| 363 totalSizeInIndexedFreeLists() + | |
| 364 _smallLinearAllocBlock._word_size) * HeapWordSize; | |
| 365 } | |
| 366 | |
| 367 size_t CompactibleFreeListSpace::max_alloc_in_words() const { | |
| 368 assert(_dictionary != NULL, "No _dictionary?"); | |
| 369 assert_locked(); | |
| 370 size_t res = _dictionary->maxChunkSize(); | |
| 371 res = MAX2(res, MIN2(_smallLinearAllocBlock._word_size, | |
| 372 (size_t) SmallForLinearAlloc - 1)); | |
| 373 // XXX the following could potentially be pretty slow; | |
| 374 // should one, pesimally for the rare cases when res | |
| 375 // caclulated above is less than IndexSetSize, | |
| 376 // just return res calculated above? My reasoning was that | |
| 377 // those cases will be so rare that the extra time spent doesn't | |
| 378 // really matter.... | |
| 379 // Note: do not change the loop test i >= res + IndexSetStride | |
| 380 // to i > res below, because i is unsigned and res may be zero. | |
| 381 for (size_t i = IndexSetSize - 1; i >= res + IndexSetStride; | |
| 382 i -= IndexSetStride) { | |
| 383 if (_indexedFreeList[i].head() != NULL) { | |
| 384 assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList"); | |
| 385 return i; | |
| 386 } | |
| 387 } | |
| 388 return res; | |
| 389 } | |
| 390 | |
| 391 void CompactibleFreeListSpace::reportFreeListStatistics() const { | |
| 392 assert_lock_strong(&_freelistLock); | |
| 393 assert(PrintFLSStatistics != 0, "Reporting error"); | |
| 394 _dictionary->reportStatistics(); | |
| 395 if (PrintFLSStatistics > 1) { | |
| 396 reportIndexedFreeListStatistics(); | |
| 397 size_t totalSize = totalSizeInIndexedFreeLists() + | |
| 398 _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())); | |
| 399 gclog_or_tty->print(" free=%ld frag=%1.4f\n", totalSize, flsFrag()); | |
| 400 } | |
| 401 } | |
| 402 | |
| 403 void CompactibleFreeListSpace::reportIndexedFreeListStatistics() const { | |
| 404 assert_lock_strong(&_freelistLock); | |
| 405 gclog_or_tty->print("Statistics for IndexedFreeLists:\n" | |
| 406 "--------------------------------\n"); | |
| 407 size_t totalSize = totalSizeInIndexedFreeLists(); | |
| 408 size_t freeBlocks = numFreeBlocksInIndexedFreeLists(); | |
| 409 gclog_or_tty->print("Total Free Space: %d\n", totalSize); | |
| 410 gclog_or_tty->print("Max Chunk Size: %d\n", maxChunkSizeInIndexedFreeLists()); | |
| 411 gclog_or_tty->print("Number of Blocks: %d\n", freeBlocks); | |
| 412 if (freeBlocks != 0) { | |
| 413 gclog_or_tty->print("Av. Block Size: %d\n", totalSize/freeBlocks); | |
| 414 } | |
| 415 } | |
| 416 | |
| 417 size_t CompactibleFreeListSpace::numFreeBlocksInIndexedFreeLists() const { | |
| 418 size_t res = 0; | |
| 419 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 420 debug_only( | |
| 421 ssize_t recount = 0; | |
| 422 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 423 fc = fc->next()) { | |
| 424 recount += 1; | |
| 425 } | |
| 426 assert(recount == _indexedFreeList[i].count(), | |
| 427 "Incorrect count in list"); | |
| 428 ) | |
| 429 res += _indexedFreeList[i].count(); | |
| 430 } | |
| 431 return res; | |
| 432 } | |
| 433 | |
| 434 size_t CompactibleFreeListSpace::maxChunkSizeInIndexedFreeLists() const { | |
| 435 for (size_t i = IndexSetSize - 1; i != 0; i -= IndexSetStride) { | |
| 436 if (_indexedFreeList[i].head() != NULL) { | |
| 437 assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList"); | |
| 438 return (size_t)i; | |
| 439 } | |
| 440 } | |
| 441 return 0; | |
| 442 } | |
| 443 | |
| 444 void CompactibleFreeListSpace::set_end(HeapWord* value) { | |
| 445 HeapWord* prevEnd = end(); | |
| 446 assert(prevEnd != value, "unnecessary set_end call"); | |
| 447 assert(prevEnd == NULL || value >= unallocated_block(), "New end is below unallocated block"); | |
| 448 _end = value; | |
| 449 if (prevEnd != NULL) { | |
| 450 // Resize the underlying block offset table. | |
| 451 _bt.resize(pointer_delta(value, bottom())); | |
| 452 if (value <= prevEnd) { | |
| 453 assert(value >= unallocated_block(), "New end is below unallocated block"); | |
| 454 } else { | |
| 455 // Now, take this new chunk and add it to the free blocks. | |
| 456 // Note that the BOT has not yet been updated for this block. | |
| 457 size_t newFcSize = pointer_delta(value, prevEnd); | |
| 458 // XXX This is REALLY UGLY and should be fixed up. XXX | |
| 459 if (!_adaptive_freelists && _smallLinearAllocBlock._ptr == NULL) { | |
| 460 // Mark the boundary of the new block in BOT | |
| 461 _bt.mark_block(prevEnd, value); | |
| 462 // put it all in the linAB | |
| 463 if (ParallelGCThreads == 0) { | |
| 464 _smallLinearAllocBlock._ptr = prevEnd; | |
| 465 _smallLinearAllocBlock._word_size = newFcSize; | |
| 466 repairLinearAllocBlock(&_smallLinearAllocBlock); | |
| 467 } else { // ParallelGCThreads > 0 | |
| 468 MutexLockerEx x(parDictionaryAllocLock(), | |
| 469 Mutex::_no_safepoint_check_flag); | |
| 470 _smallLinearAllocBlock._ptr = prevEnd; | |
| 471 _smallLinearAllocBlock._word_size = newFcSize; | |
| 472 repairLinearAllocBlock(&_smallLinearAllocBlock); | |
| 473 } | |
| 474 // Births of chunks put into a LinAB are not recorded. Births | |
| 475 // of chunks as they are allocated out of a LinAB are. | |
| 476 } else { | |
| 477 // Add the block to the free lists, if possible coalescing it | |
| 478 // with the last free block, and update the BOT and census data. | |
| 479 addChunkToFreeListsAtEndRecordingStats(prevEnd, newFcSize); | |
| 480 } | |
| 481 } | |
| 482 } | |
| 483 } | |
| 484 | |
| 485 class FreeListSpace_DCTOC : public Filtering_DCTOC { | |
| 486 CompactibleFreeListSpace* _cfls; | |
| 487 CMSCollector* _collector; | |
| 488 protected: | |
| 489 // Override. | |
| 490 #define walk_mem_region_with_cl_DECL(ClosureType) \ | |
| 491 virtual void walk_mem_region_with_cl(MemRegion mr, \ | |
| 492 HeapWord* bottom, HeapWord* top, \ | |
| 493 ClosureType* cl); \ | |
| 494 void walk_mem_region_with_cl_par(MemRegion mr, \ | |
| 495 HeapWord* bottom, HeapWord* top, \ | |
| 496 ClosureType* cl); \ | |
| 497 void walk_mem_region_with_cl_nopar(MemRegion mr, \ | |
| 498 HeapWord* bottom, HeapWord* top, \ | |
| 499 ClosureType* cl) | |
| 500 walk_mem_region_with_cl_DECL(OopClosure); | |
| 501 walk_mem_region_with_cl_DECL(FilteringClosure); | |
| 502 | |
| 503 public: | |
| 504 FreeListSpace_DCTOC(CompactibleFreeListSpace* sp, | |
| 505 CMSCollector* collector, | |
| 506 OopClosure* cl, | |
| 507 CardTableModRefBS::PrecisionStyle precision, | |
| 508 HeapWord* boundary) : | |
| 509 Filtering_DCTOC(sp, cl, precision, boundary), | |
| 510 _cfls(sp), _collector(collector) {} | |
| 511 }; | |
| 512 | |
| 513 // We de-virtualize the block-related calls below, since we know that our | |
| 514 // space is a CompactibleFreeListSpace. | |
| 515 #define FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ | |
| 516 void FreeListSpace_DCTOC::walk_mem_region_with_cl(MemRegion mr, \ | |
| 517 HeapWord* bottom, \ | |
| 518 HeapWord* top, \ | |
| 519 ClosureType* cl) { \ | |
| 520 if (SharedHeap::heap()->n_par_threads() > 0) { \ | |
| 521 walk_mem_region_with_cl_par(mr, bottom, top, cl); \ | |
| 522 } else { \ | |
| 523 walk_mem_region_with_cl_nopar(mr, bottom, top, cl); \ | |
| 524 } \ | |
| 525 } \ | |
| 526 void FreeListSpace_DCTOC::walk_mem_region_with_cl_par(MemRegion mr, \ | |
| 527 HeapWord* bottom, \ | |
| 528 HeapWord* top, \ | |
| 529 ClosureType* cl) { \ | |
| 530 /* Skip parts that are before "mr", in case "block_start" sent us \ | |
| 531 back too far. */ \ | |
| 532 HeapWord* mr_start = mr.start(); \ | |
| 533 size_t bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 534 HeapWord* next = bottom + bot_size; \ | |
| 535 while (next < mr_start) { \ | |
| 536 bottom = next; \ | |
| 537 bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 538 next = bottom + bot_size; \ | |
| 539 } \ | |
| 540 \ | |
| 541 while (bottom < top) { \ | |
| 542 if (_cfls->CompactibleFreeListSpace::block_is_obj(bottom) && \ | |
| 543 !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks( \ | |
| 544 oop(bottom)) && \ | |
| 545 !_collector->CMSCollector::is_dead_obj(oop(bottom))) { \ | |
| 546 size_t word_sz = oop(bottom)->oop_iterate(cl, mr); \ | |
| 547 bottom += _cfls->adjustObjectSize(word_sz); \ | |
| 548 } else { \ | |
| 549 bottom += _cfls->CompactibleFreeListSpace::block_size(bottom); \ | |
| 550 } \ | |
| 551 } \ | |
| 552 } \ | |
| 553 void FreeListSpace_DCTOC::walk_mem_region_with_cl_nopar(MemRegion mr, \ | |
| 554 HeapWord* bottom, \ | |
| 555 HeapWord* top, \ | |
| 556 ClosureType* cl) { \ | |
| 557 /* Skip parts that are before "mr", in case "block_start" sent us \ | |
| 558 back too far. */ \ | |
| 559 HeapWord* mr_start = mr.start(); \ | |
| 560 size_t bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 561 HeapWord* next = bottom + bot_size; \ | |
| 562 while (next < mr_start) { \ | |
| 563 bottom = next; \ | |
| 564 bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 565 next = bottom + bot_size; \ | |
| 566 } \ | |
| 567 \ | |
| 568 while (bottom < top) { \ | |
| 569 if (_cfls->CompactibleFreeListSpace::block_is_obj_nopar(bottom) && \ | |
| 570 !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks( \ | |
| 571 oop(bottom)) && \ | |
| 572 !_collector->CMSCollector::is_dead_obj(oop(bottom))) { \ | |
| 573 size_t word_sz = oop(bottom)->oop_iterate(cl, mr); \ | |
| 574 bottom += _cfls->adjustObjectSize(word_sz); \ | |
| 575 } else { \ | |
| 576 bottom += _cfls->CompactibleFreeListSpace::block_size_nopar(bottom); \ | |
| 577 } \ | |
| 578 } \ | |
| 579 } | |
| 580 | |
| 581 // (There are only two of these, rather than N, because the split is due | |
| 582 // only to the introduction of the FilteringClosure, a local part of the | |
| 583 // impl of this abstraction.) | |
| 584 FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(OopClosure) | |
| 585 FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) | |
| 586 | |
| 587 DirtyCardToOopClosure* | |
| 588 CompactibleFreeListSpace::new_dcto_cl(OopClosure* cl, | |
| 589 CardTableModRefBS::PrecisionStyle precision, | |
| 590 HeapWord* boundary) { | |
| 591 return new FreeListSpace_DCTOC(this, _collector, cl, precision, boundary); | |
| 592 } | |
| 593 | |
| 594 | |
| 595 // Note on locking for the space iteration functions: | |
| 596 // since the collector's iteration activities are concurrent with | |
| 597 // allocation activities by mutators, absent a suitable mutual exclusion | |
| 598 // mechanism the iterators may go awry. For instace a block being iterated | |
| 599 // may suddenly be allocated or divided up and part of it allocated and | |
| 600 // so on. | |
| 601 | |
| 602 // Apply the given closure to each block in the space. | |
| 603 void CompactibleFreeListSpace::blk_iterate_careful(BlkClosureCareful* cl) { | |
| 604 assert_lock_strong(freelistLock()); | |
| 605 HeapWord *cur, *limit; | |
| 606 for (cur = bottom(), limit = end(); cur < limit; | |
| 607 cur += cl->do_blk_careful(cur)); | |
| 608 } | |
| 609 | |
| 610 // Apply the given closure to each block in the space. | |
| 611 void CompactibleFreeListSpace::blk_iterate(BlkClosure* cl) { | |
| 612 assert_lock_strong(freelistLock()); | |
| 613 HeapWord *cur, *limit; | |
| 614 for (cur = bottom(), limit = end(); cur < limit; | |
| 615 cur += cl->do_blk(cur)); | |
| 616 } | |
| 617 | |
| 618 // Apply the given closure to each oop in the space. | |
| 619 void CompactibleFreeListSpace::oop_iterate(OopClosure* cl) { | |
| 620 assert_lock_strong(freelistLock()); | |
| 621 HeapWord *cur, *limit; | |
| 622 size_t curSize; | |
| 623 for (cur = bottom(), limit = end(); cur < limit; | |
| 624 cur += curSize) { | |
| 625 curSize = block_size(cur); | |
| 626 if (block_is_obj(cur)) { | |
| 627 oop(cur)->oop_iterate(cl); | |
| 628 } | |
| 629 } | |
| 630 } | |
| 631 | |
| 632 // Apply the given closure to each oop in the space \intersect memory region. | |
| 633 void CompactibleFreeListSpace::oop_iterate(MemRegion mr, OopClosure* cl) { | |
| 634 assert_lock_strong(freelistLock()); | |
| 635 if (is_empty()) { | |
| 636 return; | |
| 637 } | |
| 638 MemRegion cur = MemRegion(bottom(), end()); | |
| 639 mr = mr.intersection(cur); | |
| 640 if (mr.is_empty()) { | |
| 641 return; | |
| 642 } | |
| 643 if (mr.equals(cur)) { | |
| 644 oop_iterate(cl); | |
| 645 return; | |
| 646 } | |
| 647 assert(mr.end() <= end(), "just took an intersection above"); | |
| 648 HeapWord* obj_addr = block_start(mr.start()); | |
| 649 HeapWord* t = mr.end(); | |
| 650 | |
| 651 SpaceMemRegionOopsIterClosure smr_blk(cl, mr); | |
| 652 if (block_is_obj(obj_addr)) { | |
| 653 // Handle first object specially. | |
| 654 oop obj = oop(obj_addr); | |
| 655 obj_addr += adjustObjectSize(obj->oop_iterate(&smr_blk)); | |
| 656 } else { | |
| 657 FreeChunk* fc = (FreeChunk*)obj_addr; | |
| 658 obj_addr += fc->size(); | |
| 659 } | |
| 660 while (obj_addr < t) { | |
| 661 HeapWord* obj = obj_addr; | |
| 662 obj_addr += block_size(obj_addr); | |
| 663 // If "obj_addr" is not greater than top, then the | |
| 664 // entire object "obj" is within the region. | |
| 665 if (obj_addr <= t) { | |
| 666 if (block_is_obj(obj)) { | |
| 667 oop(obj)->oop_iterate(cl); | |
| 668 } | |
| 669 } else { | |
| 670 // "obj" extends beyond end of region | |
| 671 if (block_is_obj(obj)) { | |
| 672 oop(obj)->oop_iterate(&smr_blk); | |
| 673 } | |
| 674 break; | |
| 675 } | |
| 676 } | |
| 677 } | |
| 678 | |
| 679 // NOTE: In the following methods, in order to safely be able to | |
| 680 // apply the closure to an object, we need to be sure that the | |
| 681 // object has been initialized. We are guaranteed that an object | |
| 682 // is initialized if we are holding the Heap_lock with the | |
| 683 // world stopped. | |
| 684 void CompactibleFreeListSpace::verify_objects_initialized() const { | |
| 685 if (is_init_completed()) { | |
| 686 assert_locked_or_safepoint(Heap_lock); | |
| 687 if (Universe::is_fully_initialized()) { | |
| 688 guarantee(SafepointSynchronize::is_at_safepoint(), | |
| 689 "Required for objects to be initialized"); | |
| 690 } | |
| 691 } // else make a concession at vm start-up | |
| 692 } | |
| 693 | |
| 694 // Apply the given closure to each object in the space | |
| 695 void CompactibleFreeListSpace::object_iterate(ObjectClosure* blk) { | |
| 696 assert_lock_strong(freelistLock()); | |
| 697 NOT_PRODUCT(verify_objects_initialized()); | |
| 698 HeapWord *cur, *limit; | |
| 699 size_t curSize; | |
| 700 for (cur = bottom(), limit = end(); cur < limit; | |
| 701 cur += curSize) { | |
| 702 curSize = block_size(cur); | |
| 703 if (block_is_obj(cur)) { | |
| 704 blk->do_object(oop(cur)); | |
| 705 } | |
| 706 } | |
| 707 } | |
| 708 | |
| 709 void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr, | |
| 710 UpwardsObjectClosure* cl) { | |
| 711 assert_locked(); | |
| 712 NOT_PRODUCT(verify_objects_initialized()); | |
| 713 Space::object_iterate_mem(mr, cl); | |
| 714 } | |
| 715 | |
| 716 // Callers of this iterator beware: The closure application should | |
| 717 // be robust in the face of uninitialized objects and should (always) | |
| 718 // return a correct size so that the next addr + size below gives us a | |
| 719 // valid block boundary. [See for instance, | |
| 720 // ScanMarkedObjectsAgainCarefullyClosure::do_object_careful() | |
| 721 // in ConcurrentMarkSweepGeneration.cpp.] | |
| 722 HeapWord* | |
| 723 CompactibleFreeListSpace::object_iterate_careful(ObjectClosureCareful* cl) { | |
| 724 assert_lock_strong(freelistLock()); | |
| 725 HeapWord *addr, *last; | |
| 726 size_t size; | |
| 727 for (addr = bottom(), last = end(); | |
| 728 addr < last; addr += size) { | |
| 729 FreeChunk* fc = (FreeChunk*)addr; | |
| 730 if (fc->isFree()) { | |
| 731 // Since we hold the free list lock, which protects direct | |
| 732 // allocation in this generation by mutators, a free object | |
| 733 // will remain free throughout this iteration code. | |
| 734 size = fc->size(); | |
| 735 } else { | |
| 736 // Note that the object need not necessarily be initialized, | |
| 737 // because (for instance) the free list lock does NOT protect | |
| 738 // object initialization. The closure application below must | |
| 739 // therefore be correct in the face of uninitialized objects. | |
| 740 size = cl->do_object_careful(oop(addr)); | |
| 741 if (size == 0) { | |
| 742 // An unparsable object found. Signal early termination. | |
| 743 return addr; | |
| 744 } | |
| 745 } | |
| 746 } | |
| 747 return NULL; | |
| 748 } | |
| 749 | |
| 750 // Callers of this iterator beware: The closure application should | |
| 751 // be robust in the face of uninitialized objects and should (always) | |
| 752 // return a correct size so that the next addr + size below gives us a | |
| 753 // valid block boundary. [See for instance, | |
| 754 // ScanMarkedObjectsAgainCarefullyClosure::do_object_careful() | |
| 755 // in ConcurrentMarkSweepGeneration.cpp.] | |
| 756 HeapWord* | |
| 757 CompactibleFreeListSpace::object_iterate_careful_m(MemRegion mr, | |
| 758 ObjectClosureCareful* cl) { | |
| 759 assert_lock_strong(freelistLock()); | |
| 760 // Can't use used_region() below because it may not necessarily | |
| 761 // be the same as [bottom(),end()); although we could | |
| 762 // use [used_region().start(),round_to(used_region().end(),CardSize)), | |
| 763 // that appears too cumbersome, so we just do the simpler check | |
| 764 // in the assertion below. | |
| 765 assert(!mr.is_empty() && MemRegion(bottom(),end()).contains(mr), | |
| 766 "mr should be non-empty and within used space"); | |
| 767 HeapWord *addr, *end; | |
| 768 size_t size; | |
| 769 for (addr = block_start_careful(mr.start()), end = mr.end(); | |
| 770 addr < end; addr += size) { | |
| 771 FreeChunk* fc = (FreeChunk*)addr; | |
| 772 if (fc->isFree()) { | |
| 773 // Since we hold the free list lock, which protects direct | |
| 774 // allocation in this generation by mutators, a free object | |
| 775 // will remain free throughout this iteration code. | |
| 776 size = fc->size(); | |
| 777 } else { | |
| 778 // Note that the object need not necessarily be initialized, | |
| 779 // because (for instance) the free list lock does NOT protect | |
| 780 // object initialization. The closure application below must | |
| 781 // therefore be correct in the face of uninitialized objects. | |
| 782 size = cl->do_object_careful_m(oop(addr), mr); | |
| 783 if (size == 0) { | |
| 784 // An unparsable object found. Signal early termination. | |
| 785 return addr; | |
| 786 } | |
| 787 } | |
| 788 } | |
| 789 return NULL; | |
| 790 } | |
| 791 | |
| 792 | |
| 793 HeapWord* CompactibleFreeListSpace::block_start(const void* p) const { | |
| 794 NOT_PRODUCT(verify_objects_initialized()); | |
| 795 return _bt.block_start(p); | |
| 796 } | |
| 797 | |
| 798 HeapWord* CompactibleFreeListSpace::block_start_careful(const void* p) const { | |
| 799 return _bt.block_start_careful(p); | |
| 800 } | |
| 801 | |
| 802 size_t CompactibleFreeListSpace::block_size(const HeapWord* p) const { | |
| 803 NOT_PRODUCT(verify_objects_initialized()); | |
| 804 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 805 // This must be volatile, or else there is a danger that the compiler | |
| 806 // will compile the code below into a sometimes-infinite loop, by keeping | |
| 807 // the value read the first time in a register. | |
| 808 while (true) { | |
| 809 // We must do this until we get a consistent view of the object. | |
| 187 | 810 if (FreeChunk::indicatesFreeChunk(p)) { |
| 811 volatile FreeChunk* fc = (volatile FreeChunk*)p; | |
| 812 size_t res = fc->size(); | |
| 813 // If the object is still a free chunk, return the size, else it | |
| 814 // has been allocated so try again. | |
| 815 if (FreeChunk::indicatesFreeChunk(p)) { | |
| 0 | 816 assert(res != 0, "Block size should not be 0"); |
| 817 return res; | |
| 818 } | |
| 187 | 819 } else { |
| 820 // must read from what 'p' points to in each loop. | |
| 821 klassOop k = ((volatile oopDesc*)p)->klass_or_null(); | |
| 822 if (k != NULL) { | |
| 823 assert(k->is_oop(true /* ignore mark word */), "Should really be klass oop."); | |
| 824 oop o = (oop)p; | |
| 825 assert(o->is_parsable(), "Should be parsable"); | |
| 826 assert(o->is_oop(true /* ignore mark word */), "Should be an oop."); | |
| 827 size_t res = o->size_given_klass(k->klass_part()); | |
| 828 res = adjustObjectSize(res); | |
| 829 assert(res != 0, "Block size should not be 0"); | |
| 830 return res; | |
| 831 } | |
| 0 | 832 } |
| 833 } | |
| 834 } | |
| 835 | |
| 836 // A variant of the above that uses the Printezis bits for | |
| 837 // unparsable but allocated objects. This avoids any possible | |
| 838 // stalls waiting for mutators to initialize objects, and is | |
| 839 // thus potentially faster than the variant above. However, | |
| 840 // this variant may return a zero size for a block that is | |
| 841 // under mutation and for which a consistent size cannot be | |
| 842 // inferred without stalling; see CMSCollector::block_size_if_printezis_bits(). | |
| 843 size_t CompactibleFreeListSpace::block_size_no_stall(HeapWord* p, | |
| 844 const CMSCollector* c) | |
| 845 const { | |
| 846 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 847 // This must be volatile, or else there is a danger that the compiler | |
| 848 // will compile the code below into a sometimes-infinite loop, by keeping | |
| 849 // the value read the first time in a register. | |
| 850 DEBUG_ONLY(uint loops = 0;) | |
| 851 while (true) { | |
| 852 // We must do this until we get a consistent view of the object. | |
| 187 | 853 if (FreeChunk::indicatesFreeChunk(p)) { |
| 854 volatile FreeChunk* fc = (volatile FreeChunk*)p; | |
| 855 size_t res = fc->size(); | |
| 856 if (FreeChunk::indicatesFreeChunk(p)) { | |
| 0 | 857 assert(res != 0, "Block size should not be 0"); |
| 858 assert(loops == 0, "Should be 0"); | |
| 859 return res; | |
| 860 } | |
| 861 } else { | |
| 187 | 862 // must read from what 'p' points to in each loop. |
| 863 klassOop k = ((volatile oopDesc*)p)->klass_or_null(); | |
| 864 if (k != NULL && ((oopDesc*)p)->is_parsable()) { | |
| 865 assert(k->is_oop(), "Should really be klass oop."); | |
| 866 oop o = (oop)p; | |
| 867 assert(o->is_oop(), "Should be an oop"); | |
| 868 size_t res = o->size_given_klass(k->klass_part()); | |
| 869 res = adjustObjectSize(res); | |
| 870 assert(res != 0, "Block size should not be 0"); | |
| 871 return res; | |
| 872 } else { | |
| 873 return c->block_size_if_printezis_bits(p); | |
| 874 } | |
| 0 | 875 } |
| 876 assert(loops == 0, "Can loop at most once"); | |
| 877 DEBUG_ONLY(loops++;) | |
| 878 } | |
| 879 } | |
| 880 | |
| 881 size_t CompactibleFreeListSpace::block_size_nopar(const HeapWord* p) const { | |
| 882 NOT_PRODUCT(verify_objects_initialized()); | |
| 883 assert(MemRegion(bottom(), end()).contains(p), "p not in space"); | |
| 884 FreeChunk* fc = (FreeChunk*)p; | |
| 885 if (fc->isFree()) { | |
| 886 return fc->size(); | |
| 887 } else { | |
| 888 // Ignore mark word because this may be a recently promoted | |
| 889 // object whose mark word is used to chain together grey | |
| 890 // objects (the last one would have a null value). | |
| 891 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 892 return adjustObjectSize(oop(p)->size()); | |
| 893 } | |
| 894 } | |
| 895 | |
| 896 // This implementation assumes that the property of "being an object" is | |
| 897 // stable. But being a free chunk may not be (because of parallel | |
| 898 // promotion.) | |
| 899 bool CompactibleFreeListSpace::block_is_obj(const HeapWord* p) const { | |
| 900 FreeChunk* fc = (FreeChunk*)p; | |
| 901 assert(is_in_reserved(p), "Should be in space"); | |
| 902 // When doing a mark-sweep-compact of the CMS generation, this | |
| 903 // assertion may fail because prepare_for_compaction() uses | |
| 904 // space that is garbage to maintain information on ranges of | |
| 905 // live objects so that these live ranges can be moved as a whole. | |
| 906 // Comment out this assertion until that problem can be solved | |
| 907 // (i.e., that the block start calculation may look at objects | |
| 908 // at address below "p" in finding the object that contains "p" | |
| 909 // and those objects (if garbage) may have been modified to hold | |
| 910 // live range information. | |
| 911 // assert(ParallelGCThreads > 0 || _bt.block_start(p) == p, "Should be a block boundary"); | |
| 187 | 912 if (FreeChunk::indicatesFreeChunk(p)) return false; |
| 913 klassOop k = oop(p)->klass_or_null(); | |
| 0 | 914 if (k != NULL) { |
| 915 // Ignore mark word because it may have been used to | |
| 916 // chain together promoted objects (the last one | |
| 917 // would have a null value). | |
| 918 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 919 return true; | |
| 920 } else { | |
| 921 return false; // Was not an object at the start of collection. | |
| 922 } | |
| 923 } | |
| 924 | |
| 925 // Check if the object is alive. This fact is checked either by consulting | |
| 926 // the main marking bitmap in the sweeping phase or, if it's a permanent | |
| 927 // generation and we're not in the sweeping phase, by checking the | |
| 928 // perm_gen_verify_bit_map where we store the "deadness" information if | |
| 929 // we did not sweep the perm gen in the most recent previous GC cycle. | |
| 930 bool CompactibleFreeListSpace::obj_is_alive(const HeapWord* p) const { | |
| 931 assert (block_is_obj(p), "The address should point to an object"); | |
| 932 | |
| 933 // If we're sweeping, we use object liveness information from the main bit map | |
| 934 // for both perm gen and old gen. | |
| 935 // We don't need to lock the bitmap (live_map or dead_map below), because | |
| 936 // EITHER we are in the middle of the sweeping phase, and the | |
| 937 // main marking bit map (live_map below) is locked, | |
| 938 // OR we're in other phases and perm_gen_verify_bit_map (dead_map below) | |
| 939 // is stable, because it's mutated only in the sweeping phase. | |
| 940 if (_collector->abstract_state() == CMSCollector::Sweeping) { | |
| 941 CMSBitMap* live_map = _collector->markBitMap(); | |
| 942 return live_map->isMarked((HeapWord*) p); | |
| 943 } else { | |
| 944 // If we're not currently sweeping and we haven't swept the perm gen in | |
| 945 // the previous concurrent cycle then we may have dead but unswept objects | |
| 946 // in the perm gen. In this case, we use the "deadness" information | |
| 947 // that we had saved in perm_gen_verify_bit_map at the last sweep. | |
| 948 if (!CMSClassUnloadingEnabled && _collector->_permGen->reserved().contains(p)) { | |
| 949 if (_collector->verifying()) { | |
| 950 CMSBitMap* dead_map = _collector->perm_gen_verify_bit_map(); | |
| 951 // Object is marked in the dead_map bitmap at the previous sweep | |
| 952 // when we know that it's dead; if the bitmap is not allocated then | |
| 953 // the object is alive. | |
| 954 return (dead_map->sizeInBits() == 0) // bit_map has been allocated | |
| 955 || !dead_map->par_isMarked((HeapWord*) p); | |
| 956 } else { | |
| 957 return false; // We can't say for sure if it's live, so we say that it's dead. | |
| 958 } | |
| 959 } | |
| 960 } | |
| 961 return true; | |
| 962 } | |
| 963 | |
| 964 bool CompactibleFreeListSpace::block_is_obj_nopar(const HeapWord* p) const { | |
| 965 FreeChunk* fc = (FreeChunk*)p; | |
| 966 assert(is_in_reserved(p), "Should be in space"); | |
| 967 assert(_bt.block_start(p) == p, "Should be a block boundary"); | |
| 968 if (!fc->isFree()) { | |
| 969 // Ignore mark word because it may have been used to | |
| 970 // chain together promoted objects (the last one | |
| 971 // would have a null value). | |
| 972 assert(oop(p)->is_oop(true), "Should be an oop"); | |
| 973 return true; | |
| 974 } | |
| 975 return false; | |
| 976 } | |
| 977 | |
| 978 // "MT-safe but not guaranteed MT-precise" (TM); you may get an | |
| 979 // approximate answer if you don't hold the freelistlock when you call this. | |
| 980 size_t CompactibleFreeListSpace::totalSizeInIndexedFreeLists() const { | |
| 981 size_t size = 0; | |
| 982 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 983 debug_only( | |
| 984 // We may be calling here without the lock in which case we | |
| 985 // won't do this modest sanity check. | |
| 986 if (freelistLock()->owned_by_self()) { | |
| 987 size_t total_list_size = 0; | |
| 988 for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL; | |
| 989 fc = fc->next()) { | |
| 990 total_list_size += i; | |
| 991 } | |
| 992 assert(total_list_size == i * _indexedFreeList[i].count(), | |
| 993 "Count in list is incorrect"); | |
| 994 } | |
| 995 ) | |
| 996 size += i * _indexedFreeList[i].count(); | |
| 997 } | |
| 998 return size; | |
| 999 } | |
| 1000 | |
| 1001 HeapWord* CompactibleFreeListSpace::par_allocate(size_t size) { | |
| 1002 MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag); | |
| 1003 return allocate(size); | |
| 1004 } | |
| 1005 | |
| 1006 HeapWord* | |
| 1007 CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlockRemainder(size_t size) { | |
| 1008 return getChunkFromLinearAllocBlockRemainder(&_smallLinearAllocBlock, size); | |
| 1009 } | |
| 1010 | |
| 1011 HeapWord* CompactibleFreeListSpace::allocate(size_t size) { | |
| 1012 assert_lock_strong(freelistLock()); | |
| 1013 HeapWord* res = NULL; | |
| 1014 assert(size == adjustObjectSize(size), | |
| 1015 "use adjustObjectSize() before calling into allocate()"); | |
| 1016 | |
| 1017 if (_adaptive_freelists) { | |
| 1018 res = allocate_adaptive_freelists(size); | |
| 1019 } else { // non-adaptive free lists | |
| 1020 res = allocate_non_adaptive_freelists(size); | |
| 1021 } | |
| 1022 | |
| 1023 if (res != NULL) { | |
| 1024 // check that res does lie in this space! | |
| 1025 assert(is_in_reserved(res), "Not in this space!"); | |
| 1026 assert(is_aligned((void*)res), "alignment check"); | |
| 1027 | |
| 1028 FreeChunk* fc = (FreeChunk*)res; | |
| 1029 fc->markNotFree(); | |
| 1030 assert(!fc->isFree(), "shouldn't be marked free"); | |
| 187 | 1031 assert(oop(fc)->klass_or_null() == NULL, "should look uninitialized"); |
| 0 | 1032 // Verify that the block offset table shows this to |
| 1033 // be a single block, but not one which is unallocated. | |
| 1034 _bt.verify_single_block(res, size); | |
| 1035 _bt.verify_not_unallocated(res, size); | |
| 1036 // mangle a just allocated object with a distinct pattern. | |
| 1037 debug_only(fc->mangleAllocated(size)); | |
| 1038 } | |
| 1039 | |
| 1040 return res; | |
| 1041 } | |
| 1042 | |
| 1043 HeapWord* CompactibleFreeListSpace::allocate_non_adaptive_freelists(size_t size) { | |
| 1044 HeapWord* res = NULL; | |
| 1045 // try and use linear allocation for smaller blocks | |
| 1046 if (size < _smallLinearAllocBlock._allocation_size_limit) { | |
| 1047 // if successful, the following also adjusts block offset table | |
| 1048 res = getChunkFromSmallLinearAllocBlock(size); | |
| 1049 } | |
| 1050 // Else triage to indexed lists for smaller sizes | |
| 1051 if (res == NULL) { | |
| 1052 if (size < SmallForDictionary) { | |
| 1053 res = (HeapWord*) getChunkFromIndexedFreeList(size); | |
| 1054 } else { | |
| 1055 // else get it from the big dictionary; if even this doesn't | |
| 1056 // work we are out of luck. | |
| 1057 res = (HeapWord*)getChunkFromDictionaryExact(size); | |
| 1058 } | |
| 1059 } | |
| 1060 | |
| 1061 return res; | |
| 1062 } | |
| 1063 | |
| 1064 HeapWord* CompactibleFreeListSpace::allocate_adaptive_freelists(size_t size) { | |
| 1065 assert_lock_strong(freelistLock()); | |
| 1066 HeapWord* res = NULL; | |
| 1067 assert(size == adjustObjectSize(size), | |
| 1068 "use adjustObjectSize() before calling into allocate()"); | |
| 1069 | |
| 1070 // Strategy | |
| 1071 // if small | |
| 1072 // exact size from small object indexed list if small | |
| 1073 // small or large linear allocation block (linAB) as appropriate | |
| 1074 // take from lists of greater sized chunks | |
| 1075 // else | |
| 1076 // dictionary | |
| 1077 // small or large linear allocation block if it has the space | |
| 1078 // Try allocating exact size from indexTable first | |
| 1079 if (size < IndexSetSize) { | |
| 1080 res = (HeapWord*) getChunkFromIndexedFreeList(size); | |
| 1081 if(res != NULL) { | |
| 1082 assert(res != (HeapWord*)_indexedFreeList[size].head(), | |
| 1083 "Not removed from free list"); | |
| 1084 // no block offset table adjustment is necessary on blocks in | |
| 1085 // the indexed lists. | |
| 1086 | |
| 1087 // Try allocating from the small LinAB | |
| 1088 } else if (size < _smallLinearAllocBlock._allocation_size_limit && | |
| 1089 (res = getChunkFromSmallLinearAllocBlock(size)) != NULL) { | |
| 1090 // if successful, the above also adjusts block offset table | |
| 1091 // Note that this call will refill the LinAB to | |
| 1092 // satisfy the request. This is different that | |
| 1093 // evm. | |
| 1094 // Don't record chunk off a LinAB? smallSplitBirth(size); | |
| 1095 | |
| 1096 } else { | |
| 1097 // Raid the exact free lists larger than size, even if they are not | |
| 1098 // overpopulated. | |
| 1099 res = (HeapWord*) getChunkFromGreater(size); | |
| 1100 } | |
| 1101 } else { | |
| 1102 // Big objects get allocated directly from the dictionary. | |
| 1103 res = (HeapWord*) getChunkFromDictionaryExact(size); | |
| 1104 if (res == NULL) { | |
| 1105 // Try hard not to fail since an allocation failure will likely | |
| 1106 // trigger a synchronous GC. Try to get the space from the | |
| 1107 // allocation blocks. | |
| 1108 res = getChunkFromSmallLinearAllocBlockRemainder(size); | |
| 1109 } | |
| 1110 } | |
| 1111 | |
| 1112 return res; | |
| 1113 } | |
| 1114 | |
| 1115 // A worst-case estimate of the space required (in HeapWords) to expand the heap | |
| 1116 // when promoting obj. | |
| 1117 size_t CompactibleFreeListSpace::expansionSpaceRequired(size_t obj_size) const { | |
| 1118 // Depending on the object size, expansion may require refilling either a | |
| 1119 // bigLAB or a smallLAB plus refilling a PromotionInfo object. MinChunkSize | |
| 1120 // is added because the dictionary may over-allocate to avoid fragmentation. | |
| 1121 size_t space = obj_size; | |
| 1122 if (!_adaptive_freelists) { | |
| 1123 space = MAX2(space, _smallLinearAllocBlock._refillSize); | |
| 1124 } | |
| 1125 space += _promoInfo.refillSize() + 2 * MinChunkSize; | |
| 1126 return space; | |
| 1127 } | |
| 1128 | |
| 1129 FreeChunk* CompactibleFreeListSpace::getChunkFromGreater(size_t numWords) { | |
| 1130 FreeChunk* ret; | |
| 1131 | |
| 1132 assert(numWords >= MinChunkSize, "Size is less than minimum"); | |
| 1133 assert(linearAllocationWouldFail() || bestFitFirst(), | |
| 1134 "Should not be here"); | |
| 1135 | |
| 1136 size_t i; | |
| 1137 size_t currSize = numWords + MinChunkSize; | |
| 1138 assert(currSize % MinObjAlignment == 0, "currSize should be aligned"); | |
| 1139 for (i = currSize; i < IndexSetSize; i += IndexSetStride) { | |
| 1140 FreeList* fl = &_indexedFreeList[i]; | |
| 1141 if (fl->head()) { | |
| 1142 ret = getFromListGreater(fl, numWords); | |
| 1143 assert(ret == NULL || ret->isFree(), "Should be returning a free chunk"); | |
| 1144 return ret; | |
| 1145 } | |
| 1146 } | |
| 1147 | |
| 1148 currSize = MAX2((size_t)SmallForDictionary, | |
| 1149 (size_t)(numWords + MinChunkSize)); | |
| 1150 | |
| 1151 /* Try to get a chunk that satisfies request, while avoiding | |
| 1152 fragmentation that can't be handled. */ | |
| 1153 { | |
| 1154 ret = dictionary()->getChunk(currSize); | |
| 1155 if (ret != NULL) { | |
| 1156 assert(ret->size() - numWords >= MinChunkSize, | |
| 1157 "Chunk is too small"); | |
| 1158 _bt.allocated((HeapWord*)ret, ret->size()); | |
| 1159 /* Carve returned chunk. */ | |
| 1160 (void) splitChunkAndReturnRemainder(ret, numWords); | |
| 1161 /* Label this as no longer a free chunk. */ | |
| 1162 assert(ret->isFree(), "This chunk should be free"); | |
| 1163 ret->linkPrev(NULL); | |
| 1164 } | |
| 1165 assert(ret == NULL || ret->isFree(), "Should be returning a free chunk"); | |
| 1166 return ret; | |
| 1167 } | |
| 1168 ShouldNotReachHere(); | |
| 1169 } | |
| 1170 | |
| 1171 bool CompactibleFreeListSpace::verifyChunkInIndexedFreeLists(FreeChunk* fc) | |
| 1172 const { | |
| 1173 assert(fc->size() < IndexSetSize, "Size of chunk is too large"); | |
| 1174 return _indexedFreeList[fc->size()].verifyChunkInFreeLists(fc); | |
| 1175 } | |
| 1176 | |
| 1177 bool CompactibleFreeListSpace::verifyChunkInFreeLists(FreeChunk* fc) const { | |
| 1178 if (fc->size() >= IndexSetSize) { | |
| 1179 return dictionary()->verifyChunkInFreeLists(fc); | |
| 1180 } else { | |
| 1181 return verifyChunkInIndexedFreeLists(fc); | |
| 1182 } | |
| 1183 } | |
| 1184 | |
| 1185 #ifndef PRODUCT | |
| 1186 void CompactibleFreeListSpace::assert_locked() const { | |
| 1187 CMSLockVerifier::assert_locked(freelistLock(), parDictionaryAllocLock()); | |
| 1188 } | |
| 1189 #endif | |
| 1190 | |
| 1191 FreeChunk* CompactibleFreeListSpace::allocateScratch(size_t size) { | |
| 1192 // In the parallel case, the main thread holds the free list lock | |
| 1193 // on behalf the parallel threads. | |
| 1194 assert_locked(); | |
| 1195 FreeChunk* fc; | |
| 1196 { | |
| 1197 // If GC is parallel, this might be called by several threads. | |
| 1198 // This should be rare enough that the locking overhead won't affect | |
| 1199 // the sequential code. | |
| 1200 MutexLockerEx x(parDictionaryAllocLock(), | |
| 1201 Mutex::_no_safepoint_check_flag); | |
| 1202 fc = getChunkFromDictionary(size); | |
| 1203 } | |
| 1204 if (fc != NULL) { | |
| 1205 fc->dontCoalesce(); | |
| 1206 assert(fc->isFree(), "Should be free, but not coalescable"); | |
| 1207 // Verify that the block offset table shows this to | |
| 1208 // be a single block, but not one which is unallocated. | |
| 1209 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 1210 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 1211 } | |
| 1212 return fc; | |
| 1213 } | |
| 1214 | |
|
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ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
12
diff
changeset
|
1215 oop CompactibleFreeListSpace::promote(oop obj, size_t obj_size) { |
| 0 | 1216 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); |
| 1217 assert_locked(); | |
| 1218 | |
| 1219 // if we are tracking promotions, then first ensure space for | |
| 1220 // promotion (including spooling space for saving header if necessary). | |
| 1221 // then allocate and copy, then track promoted info if needed. | |
| 1222 // When tracking (see PromotionInfo::track()), the mark word may | |
| 1223 // be displaced and in this case restoration of the mark word | |
| 1224 // occurs in the (oop_since_save_marks_)iterate phase. | |
| 1225 if (_promoInfo.tracking() && !_promoInfo.ensure_spooling_space()) { | |
| 1226 return NULL; | |
| 1227 } | |
| 1228 // Call the allocate(size_t, bool) form directly to avoid the | |
| 1229 // additional call through the allocate(size_t) form. Having | |
| 1230 // the compile inline the call is problematic because allocate(size_t) | |
| 1231 // is a virtual method. | |
| 1232 HeapWord* res = allocate(adjustObjectSize(obj_size)); | |
| 1233 if (res != NULL) { | |
| 1234 Copy::aligned_disjoint_words((HeapWord*)obj, res, obj_size); | |
| 1235 // if we should be tracking promotions, do so. | |
| 1236 if (_promoInfo.tracking()) { | |
| 1237 _promoInfo.track((PromotedObject*)res); | |
| 1238 } | |
| 1239 } | |
| 1240 return oop(res); | |
| 1241 } | |
| 1242 | |
| 1243 HeapWord* | |
| 1244 CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlock(size_t size) { | |
| 1245 assert_locked(); | |
| 1246 assert(size >= MinChunkSize, "minimum chunk size"); | |
| 1247 assert(size < _smallLinearAllocBlock._allocation_size_limit, | |
| 1248 "maximum from smallLinearAllocBlock"); | |
| 1249 return getChunkFromLinearAllocBlock(&_smallLinearAllocBlock, size); | |
| 1250 } | |
| 1251 | |
| 1252 HeapWord* | |
| 1253 CompactibleFreeListSpace::getChunkFromLinearAllocBlock(LinearAllocBlock *blk, | |
| 1254 size_t size) { | |
| 1255 assert_locked(); | |
| 1256 assert(size >= MinChunkSize, "too small"); | |
| 1257 HeapWord* res = NULL; | |
| 1258 // Try to do linear allocation from blk, making sure that | |
| 1259 if (blk->_word_size == 0) { | |
| 1260 // We have probably been unable to fill this either in the prologue or | |
| 1261 // when it was exhausted at the last linear allocation. Bail out until | |
| 1262 // next time. | |
| 1263 assert(blk->_ptr == NULL, "consistency check"); | |
| 1264 return NULL; | |
| 1265 } | |
| 1266 assert(blk->_word_size != 0 && blk->_ptr != NULL, "consistency check"); | |
| 1267 res = getChunkFromLinearAllocBlockRemainder(blk, size); | |
| 1268 if (res != NULL) return res; | |
| 1269 | |
| 1270 // about to exhaust this linear allocation block | |
| 1271 if (blk->_word_size == size) { // exactly satisfied | |
| 1272 res = blk->_ptr; | |
| 1273 _bt.allocated(res, blk->_word_size); | |
| 1274 } else if (size + MinChunkSize <= blk->_refillSize) { | |
| 1275 // Update _unallocated_block if the size is such that chunk would be | |
| 1276 // returned to the indexed free list. All other chunks in the indexed | |
| 1277 // free lists are allocated from the dictionary so that _unallocated_block | |
| 1278 // has already been adjusted for them. Do it here so that the cost | |
| 1279 // for all chunks added back to the indexed free lists. | |
| 1280 if (blk->_word_size < SmallForDictionary) { | |
| 1281 _bt.allocated(blk->_ptr, blk->_word_size); | |
| 1282 } | |
| 1283 // Return the chunk that isn't big enough, and then refill below. | |
| 1284 addChunkToFreeLists(blk->_ptr, blk->_word_size); | |
| 1285 _bt.verify_single_block(blk->_ptr, (blk->_ptr + blk->_word_size)); | |
| 1286 // Don't keep statistics on adding back chunk from a LinAB. | |
| 1287 } else { | |
| 1288 // A refilled block would not satisfy the request. | |
| 1289 return NULL; | |
| 1290 } | |
| 1291 | |
| 1292 blk->_ptr = NULL; blk->_word_size = 0; | |
| 1293 refillLinearAllocBlock(blk); | |
| 1294 assert(blk->_ptr == NULL || blk->_word_size >= size + MinChunkSize, | |
| 1295 "block was replenished"); | |
| 1296 if (res != NULL) { | |
| 1297 splitBirth(size); | |
| 1298 repairLinearAllocBlock(blk); | |
| 1299 } else if (blk->_ptr != NULL) { | |
| 1300 res = blk->_ptr; | |
| 1301 size_t blk_size = blk->_word_size; | |
| 1302 blk->_word_size -= size; | |
| 1303 blk->_ptr += size; | |
| 1304 splitBirth(size); | |
| 1305 repairLinearAllocBlock(blk); | |
| 1306 // Update BOT last so that other (parallel) GC threads see a consistent | |
| 1307 // view of the BOT and free blocks. | |
| 1308 // Above must occur before BOT is updated below. | |
| 1309 _bt.split_block(res, blk_size, size); // adjust block offset table | |
| 1310 } | |
| 1311 return res; | |
| 1312 } | |
| 1313 | |
| 1314 HeapWord* CompactibleFreeListSpace::getChunkFromLinearAllocBlockRemainder( | |
| 1315 LinearAllocBlock* blk, | |
| 1316 size_t size) { | |
| 1317 assert_locked(); | |
| 1318 assert(size >= MinChunkSize, "too small"); | |
| 1319 | |
| 1320 HeapWord* res = NULL; | |
| 1321 // This is the common case. Keep it simple. | |
| 1322 if (blk->_word_size >= size + MinChunkSize) { | |
| 1323 assert(blk->_ptr != NULL, "consistency check"); | |
| 1324 res = blk->_ptr; | |
| 1325 // Note that the BOT is up-to-date for the linAB before allocation. It | |
| 1326 // indicates the start of the linAB. The split_block() updates the | |
| 1327 // BOT for the linAB after the allocation (indicates the start of the | |
| 1328 // next chunk to be allocated). | |
| 1329 size_t blk_size = blk->_word_size; | |
| 1330 blk->_word_size -= size; | |
| 1331 blk->_ptr += size; | |
| 1332 splitBirth(size); | |
| 1333 repairLinearAllocBlock(blk); | |
| 1334 // Update BOT last so that other (parallel) GC threads see a consistent | |
| 1335 // view of the BOT and free blocks. | |
| 1336 // Above must occur before BOT is updated below. | |
| 1337 _bt.split_block(res, blk_size, size); // adjust block offset table | |
| 1338 _bt.allocated(res, size); | |
| 1339 } | |
| 1340 return res; | |
| 1341 } | |
| 1342 | |
| 1343 FreeChunk* | |
| 1344 CompactibleFreeListSpace::getChunkFromIndexedFreeList(size_t size) { | |
| 1345 assert_locked(); | |
| 1346 assert(size < SmallForDictionary, "just checking"); | |
| 1347 FreeChunk* res; | |
| 1348 res = _indexedFreeList[size].getChunkAtHead(); | |
| 1349 if (res == NULL) { | |
| 1350 res = getChunkFromIndexedFreeListHelper(size); | |
| 1351 } | |
| 1352 _bt.verify_not_unallocated((HeapWord*) res, size); | |
| 1353 return res; | |
| 1354 } | |
| 1355 | |
| 1356 FreeChunk* | |
| 1357 CompactibleFreeListSpace::getChunkFromIndexedFreeListHelper(size_t size) { | |
| 1358 assert_locked(); | |
| 1359 FreeChunk* fc = NULL; | |
| 1360 if (size < SmallForDictionary) { | |
| 1361 assert(_indexedFreeList[size].head() == NULL || | |
| 1362 _indexedFreeList[size].surplus() <= 0, | |
| 1363 "List for this size should be empty or under populated"); | |
| 1364 // Try best fit in exact lists before replenishing the list | |
| 1365 if (!bestFitFirst() || (fc = bestFitSmall(size)) == NULL) { | |
| 1366 // Replenish list. | |
| 1367 // | |
| 1368 // Things tried that failed. | |
| 1369 // Tried allocating out of the two LinAB's first before | |
| 1370 // replenishing lists. | |
| 1371 // Tried small linAB of size 256 (size in indexed list) | |
| 1372 // and replenishing indexed lists from the small linAB. | |
| 1373 // | |
| 1374 FreeChunk* newFc = NULL; | |
| 1375 size_t replenish_size = CMSIndexedFreeListReplenish * size; | |
| 1376 if (replenish_size < SmallForDictionary) { | |
| 1377 // Do not replenish from an underpopulated size. | |
| 1378 if (_indexedFreeList[replenish_size].surplus() > 0 && | |
| 1379 _indexedFreeList[replenish_size].head() != NULL) { | |
| 1380 newFc = | |
| 1381 _indexedFreeList[replenish_size].getChunkAtHead(); | |
| 1382 } else { | |
| 1383 newFc = bestFitSmall(replenish_size); | |
| 1384 } | |
| 1385 } | |
| 1386 if (newFc != NULL) { | |
| 1387 splitDeath(replenish_size); | |
| 1388 } else if (replenish_size > size) { | |
| 1389 assert(CMSIndexedFreeListReplenish > 1, "ctl pt invariant"); | |
| 1390 newFc = | |
| 1391 getChunkFromIndexedFreeListHelper(replenish_size); | |
| 1392 } | |
| 1393 if (newFc != NULL) { | |
| 1394 assert(newFc->size() == replenish_size, "Got wrong size"); | |
| 1395 size_t i; | |
| 1396 FreeChunk *curFc, *nextFc; | |
| 1397 // carve up and link blocks 0, ..., CMSIndexedFreeListReplenish - 2 | |
| 1398 // The last chunk is not added to the lists but is returned as the | |
| 1399 // free chunk. | |
| 1400 for (curFc = newFc, nextFc = (FreeChunk*)((HeapWord*)curFc + size), | |
| 1401 i = 0; | |
| 1402 i < (CMSIndexedFreeListReplenish - 1); | |
| 1403 curFc = nextFc, nextFc = (FreeChunk*)((HeapWord*)nextFc + size), | |
| 1404 i++) { | |
| 1405 curFc->setSize(size); | |
| 1406 // Don't record this as a return in order to try and | |
| 1407 // determine the "returns" from a GC. | |
| 1408 _bt.verify_not_unallocated((HeapWord*) fc, size); | |
| 1409 _indexedFreeList[size].returnChunkAtTail(curFc, false); | |
| 1410 _bt.mark_block((HeapWord*)curFc, size); | |
| 1411 splitBirth(size); | |
| 1412 // Don't record the initial population of the indexed list | |
| 1413 // as a split birth. | |
| 1414 } | |
| 1415 | |
| 1416 // check that the arithmetic was OK above | |
| 1417 assert((HeapWord*)nextFc == (HeapWord*)newFc + replenish_size, | |
| 1418 "inconsistency in carving newFc"); | |
| 1419 curFc->setSize(size); | |
| 1420 _bt.mark_block((HeapWord*)curFc, size); | |
| 1421 splitBirth(size); | |
| 1422 return curFc; | |
| 1423 } | |
| 1424 } | |
| 1425 } else { | |
| 1426 // Get a free chunk from the free chunk dictionary to be returned to | |
| 1427 // replenish the indexed free list. | |
| 1428 fc = getChunkFromDictionaryExact(size); | |
| 1429 } | |
| 1430 assert(fc == NULL || fc->isFree(), "Should be returning a free chunk"); | |
| 1431 return fc; | |
| 1432 } | |
| 1433 | |
| 1434 FreeChunk* | |
| 1435 CompactibleFreeListSpace::getChunkFromDictionary(size_t size) { | |
| 1436 assert_locked(); | |
| 1437 FreeChunk* fc = _dictionary->getChunk(size); | |
| 1438 if (fc == NULL) { | |
| 1439 return NULL; | |
| 1440 } | |
| 1441 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1442 if (fc->size() >= size + MinChunkSize) { | |
| 1443 fc = splitChunkAndReturnRemainder(fc, size); | |
| 1444 } | |
| 1445 assert(fc->size() >= size, "chunk too small"); | |
| 1446 assert(fc->size() < size + MinChunkSize, "chunk too big"); | |
| 1447 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 1448 return fc; | |
| 1449 } | |
| 1450 | |
| 1451 FreeChunk* | |
| 1452 CompactibleFreeListSpace::getChunkFromDictionaryExact(size_t size) { | |
| 1453 assert_locked(); | |
| 1454 FreeChunk* fc = _dictionary->getChunk(size); | |
| 1455 if (fc == NULL) { | |
| 1456 return fc; | |
| 1457 } | |
| 1458 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1459 if (fc->size() == size) { | |
| 1460 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1461 return fc; | |
| 1462 } | |
| 1463 assert(fc->size() > size, "getChunk() guarantee"); | |
| 1464 if (fc->size() < size + MinChunkSize) { | |
| 1465 // Return the chunk to the dictionary and go get a bigger one. | |
| 1466 returnChunkToDictionary(fc); | |
| 1467 fc = _dictionary->getChunk(size + MinChunkSize); | |
| 1468 if (fc == NULL) { | |
| 1469 return NULL; | |
| 1470 } | |
| 1471 _bt.allocated((HeapWord*)fc, fc->size()); | |
| 1472 } | |
| 1473 assert(fc->size() >= size + MinChunkSize, "tautology"); | |
| 1474 fc = splitChunkAndReturnRemainder(fc, size); | |
| 1475 assert(fc->size() == size, "chunk is wrong size"); | |
| 1476 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1477 return fc; | |
| 1478 } | |
| 1479 | |
| 1480 void | |
| 1481 CompactibleFreeListSpace::returnChunkToDictionary(FreeChunk* chunk) { | |
| 1482 assert_locked(); | |
| 1483 | |
| 1484 size_t size = chunk->size(); | |
| 1485 _bt.verify_single_block((HeapWord*)chunk, size); | |
| 1486 // adjust _unallocated_block downward, as necessary | |
| 1487 _bt.freed((HeapWord*)chunk, size); | |
| 1488 _dictionary->returnChunk(chunk); | |
| 1489 } | |
| 1490 | |
| 1491 void | |
| 1492 CompactibleFreeListSpace::returnChunkToFreeList(FreeChunk* fc) { | |
| 1493 assert_locked(); | |
| 1494 size_t size = fc->size(); | |
| 1495 _bt.verify_single_block((HeapWord*) fc, size); | |
| 1496 _bt.verify_not_unallocated((HeapWord*) fc, size); | |
| 1497 if (_adaptive_freelists) { | |
| 1498 _indexedFreeList[size].returnChunkAtTail(fc); | |
| 1499 } else { | |
| 1500 _indexedFreeList[size].returnChunkAtHead(fc); | |
| 1501 } | |
| 1502 } | |
| 1503 | |
| 1504 // Add chunk to end of last block -- if it's the largest | |
| 1505 // block -- and update BOT and census data. We would | |
| 1506 // of course have preferred to coalesce it with the | |
| 1507 // last block, but it's currently less expensive to find the | |
| 1508 // largest block than it is to find the last. | |
| 1509 void | |
| 1510 CompactibleFreeListSpace::addChunkToFreeListsAtEndRecordingStats( | |
| 1511 HeapWord* chunk, size_t size) { | |
| 1512 // check that the chunk does lie in this space! | |
| 1513 assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!"); | |
| 1514 assert_locked(); | |
| 1515 // One of the parallel gc task threads may be here | |
| 1516 // whilst others are allocating. | |
| 1517 Mutex* lock = NULL; | |
| 1518 if (ParallelGCThreads != 0) { | |
| 1519 lock = &_parDictionaryAllocLock; | |
| 1520 } | |
| 1521 FreeChunk* ec; | |
| 1522 { | |
| 1523 MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag); | |
| 1524 ec = dictionary()->findLargestDict(); // get largest block | |
| 1525 if (ec != NULL && ec->end() == chunk) { | |
| 1526 // It's a coterminal block - we can coalesce. | |
| 1527 size_t old_size = ec->size(); | |
| 1528 coalDeath(old_size); | |
| 1529 removeChunkFromDictionary(ec); | |
| 1530 size += old_size; | |
| 1531 } else { | |
| 1532 ec = (FreeChunk*)chunk; | |
| 1533 } | |
| 1534 } | |
| 1535 ec->setSize(size); | |
| 1536 debug_only(ec->mangleFreed(size)); | |
| 1537 if (size < SmallForDictionary) { | |
| 1538 lock = _indexedFreeListParLocks[size]; | |
| 1539 } | |
| 1540 MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag); | |
| 1541 addChunkAndRepairOffsetTable((HeapWord*)ec, size, true); | |
| 1542 // record the birth under the lock since the recording involves | |
| 1543 // manipulation of the list on which the chunk lives and | |
| 1544 // if the chunk is allocated and is the last on the list, | |
| 1545 // the list can go away. | |
| 1546 coalBirth(size); | |
| 1547 } | |
| 1548 | |
| 1549 void | |
| 1550 CompactibleFreeListSpace::addChunkToFreeLists(HeapWord* chunk, | |
| 1551 size_t size) { | |
| 1552 // check that the chunk does lie in this space! | |
| 1553 assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!"); | |
| 1554 assert_locked(); | |
| 1555 _bt.verify_single_block(chunk, size); | |
| 1556 | |
| 1557 FreeChunk* fc = (FreeChunk*) chunk; | |
| 1558 fc->setSize(size); | |
| 1559 debug_only(fc->mangleFreed(size)); | |
| 1560 if (size < SmallForDictionary) { | |
| 1561 returnChunkToFreeList(fc); | |
| 1562 } else { | |
| 1563 returnChunkToDictionary(fc); | |
| 1564 } | |
| 1565 } | |
| 1566 | |
| 1567 void | |
| 1568 CompactibleFreeListSpace::addChunkAndRepairOffsetTable(HeapWord* chunk, | |
| 1569 size_t size, bool coalesced) { | |
| 1570 assert_locked(); | |
| 1571 assert(chunk != NULL, "null chunk"); | |
| 1572 if (coalesced) { | |
| 1573 // repair BOT | |
| 1574 _bt.single_block(chunk, size); | |
| 1575 } | |
| 1576 addChunkToFreeLists(chunk, size); | |
| 1577 } | |
| 1578 | |
| 1579 // We _must_ find the purported chunk on our free lists; | |
| 1580 // we assert if we don't. | |
| 1581 void | |
| 1582 CompactibleFreeListSpace::removeFreeChunkFromFreeLists(FreeChunk* fc) { | |
| 1583 size_t size = fc->size(); | |
| 1584 assert_locked(); | |
| 1585 debug_only(verifyFreeLists()); | |
| 1586 if (size < SmallForDictionary) { | |
| 1587 removeChunkFromIndexedFreeList(fc); | |
| 1588 } else { | |
| 1589 removeChunkFromDictionary(fc); | |
| 1590 } | |
| 1591 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1592 debug_only(verifyFreeLists()); | |
| 1593 } | |
| 1594 | |
| 1595 void | |
| 1596 CompactibleFreeListSpace::removeChunkFromDictionary(FreeChunk* fc) { | |
| 1597 size_t size = fc->size(); | |
| 1598 assert_locked(); | |
| 1599 assert(fc != NULL, "null chunk"); | |
| 1600 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1601 _dictionary->removeChunk(fc); | |
| 1602 // adjust _unallocated_block upward, as necessary | |
| 1603 _bt.allocated((HeapWord*)fc, size); | |
| 1604 } | |
| 1605 | |
| 1606 void | |
| 1607 CompactibleFreeListSpace::removeChunkFromIndexedFreeList(FreeChunk* fc) { | |
| 1608 assert_locked(); | |
| 1609 size_t size = fc->size(); | |
| 1610 _bt.verify_single_block((HeapWord*)fc, size); | |
| 1611 NOT_PRODUCT( | |
| 1612 if (FLSVerifyIndexTable) { | |
| 1613 verifyIndexedFreeList(size); | |
| 1614 } | |
| 1615 ) | |
| 1616 _indexedFreeList[size].removeChunk(fc); | |
| 1617 debug_only(fc->clearNext()); | |
| 1618 debug_only(fc->clearPrev()); | |
| 1619 NOT_PRODUCT( | |
| 1620 if (FLSVerifyIndexTable) { | |
| 1621 verifyIndexedFreeList(size); | |
| 1622 } | |
| 1623 ) | |
| 1624 } | |
| 1625 | |
| 1626 FreeChunk* CompactibleFreeListSpace::bestFitSmall(size_t numWords) { | |
| 1627 /* A hint is the next larger size that has a surplus. | |
| 1628 Start search at a size large enough to guarantee that | |
| 1629 the excess is >= MIN_CHUNK. */ | |
| 1630 size_t start = align_object_size(numWords + MinChunkSize); | |
| 1631 if (start < IndexSetSize) { | |
| 1632 FreeList* it = _indexedFreeList; | |
| 1633 size_t hint = _indexedFreeList[start].hint(); | |
| 1634 while (hint < IndexSetSize) { | |
| 1635 assert(hint % MinObjAlignment == 0, "hint should be aligned"); | |
| 1636 FreeList *fl = &_indexedFreeList[hint]; | |
| 1637 if (fl->surplus() > 0 && fl->head() != NULL) { | |
| 1638 // Found a list with surplus, reset original hint | |
| 1639 // and split out a free chunk which is returned. | |
| 1640 _indexedFreeList[start].set_hint(hint); | |
| 1641 FreeChunk* res = getFromListGreater(fl, numWords); | |
| 1642 assert(res == NULL || res->isFree(), | |
| 1643 "Should be returning a free chunk"); | |
| 1644 return res; | |
| 1645 } | |
| 1646 hint = fl->hint(); /* keep looking */ | |
| 1647 } | |
| 1648 /* None found. */ | |
| 1649 it[start].set_hint(IndexSetSize); | |
| 1650 } | |
| 1651 return NULL; | |
| 1652 } | |
| 1653 | |
| 1654 /* Requires fl->size >= numWords + MinChunkSize */ | |
| 1655 FreeChunk* CompactibleFreeListSpace::getFromListGreater(FreeList* fl, | |
| 1656 size_t numWords) { | |
| 1657 FreeChunk *curr = fl->head(); | |
| 1658 size_t oldNumWords = curr->size(); | |
| 1659 assert(numWords >= MinChunkSize, "Word size is too small"); | |
| 1660 assert(curr != NULL, "List is empty"); | |
| 1661 assert(oldNumWords >= numWords + MinChunkSize, | |
| 1662 "Size of chunks in the list is too small"); | |
| 1663 | |
| 1664 fl->removeChunk(curr); | |
| 1665 // recorded indirectly by splitChunkAndReturnRemainder - | |
| 1666 // smallSplit(oldNumWords, numWords); | |
| 1667 FreeChunk* new_chunk = splitChunkAndReturnRemainder(curr, numWords); | |
| 1668 // Does anything have to be done for the remainder in terms of | |
| 1669 // fixing the card table? | |
| 1670 assert(new_chunk == NULL || new_chunk->isFree(), | |
| 1671 "Should be returning a free chunk"); | |
| 1672 return new_chunk; | |
| 1673 } | |
| 1674 | |
| 1675 FreeChunk* | |
| 1676 CompactibleFreeListSpace::splitChunkAndReturnRemainder(FreeChunk* chunk, | |
| 1677 size_t new_size) { | |
| 1678 assert_locked(); | |
| 1679 size_t size = chunk->size(); | |
| 1680 assert(size > new_size, "Split from a smaller block?"); | |
| 1681 assert(is_aligned(chunk), "alignment problem"); | |
| 1682 assert(size == adjustObjectSize(size), "alignment problem"); | |
| 1683 size_t rem_size = size - new_size; | |
| 1684 assert(rem_size == adjustObjectSize(rem_size), "alignment problem"); | |
| 1685 assert(rem_size >= MinChunkSize, "Free chunk smaller than minimum"); | |
| 1686 FreeChunk* ffc = (FreeChunk*)((HeapWord*)chunk + new_size); | |
| 1687 assert(is_aligned(ffc), "alignment problem"); | |
| 1688 ffc->setSize(rem_size); | |
| 1689 ffc->linkNext(NULL); | |
| 1690 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. | |
| 1691 // Above must occur before BOT is updated below. | |
| 1692 // adjust block offset table | |
| 1693 _bt.split_block((HeapWord*)chunk, chunk->size(), new_size); | |
| 1694 if (rem_size < SmallForDictionary) { | |
| 1695 bool is_par = (SharedHeap::heap()->n_par_threads() > 0); | |
| 1696 if (is_par) _indexedFreeListParLocks[rem_size]->lock(); | |
| 1697 returnChunkToFreeList(ffc); | |
| 1698 split(size, rem_size); | |
| 1699 if (is_par) _indexedFreeListParLocks[rem_size]->unlock(); | |
| 1700 } else { | |
| 1701 returnChunkToDictionary(ffc); | |
| 1702 split(size ,rem_size); | |
| 1703 } | |
| 1704 chunk->setSize(new_size); | |
| 1705 return chunk; | |
| 1706 } | |
| 1707 | |
| 1708 void | |
| 1709 CompactibleFreeListSpace::sweep_completed() { | |
| 1710 // Now that space is probably plentiful, refill linear | |
| 1711 // allocation blocks as needed. | |
| 1712 refillLinearAllocBlocksIfNeeded(); | |
| 1713 } | |
| 1714 | |
| 1715 void | |
| 1716 CompactibleFreeListSpace::gc_prologue() { | |
| 1717 assert_locked(); | |
| 1718 if (PrintFLSStatistics != 0) { | |
| 1719 gclog_or_tty->print("Before GC:\n"); | |
| 1720 reportFreeListStatistics(); | |
| 1721 } | |
| 1722 refillLinearAllocBlocksIfNeeded(); | |
| 1723 } | |
| 1724 | |
| 1725 void | |
| 1726 CompactibleFreeListSpace::gc_epilogue() { | |
| 1727 assert_locked(); | |
| 1728 if (PrintGCDetails && Verbose && !_adaptive_freelists) { | |
| 1729 if (_smallLinearAllocBlock._word_size == 0) | |
| 1730 warning("CompactibleFreeListSpace(epilogue):: Linear allocation failure"); | |
| 1731 } | |
| 1732 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); | |
| 1733 _promoInfo.stopTrackingPromotions(); | |
| 1734 repairLinearAllocationBlocks(); | |
| 1735 // Print Space's stats | |
| 1736 if (PrintFLSStatistics != 0) { | |
| 1737 gclog_or_tty->print("After GC:\n"); | |
| 1738 reportFreeListStatistics(); | |
| 1739 } | |
| 1740 } | |
| 1741 | |
| 1742 // Iteration support, mostly delegated from a CMS generation | |
| 1743 | |
| 1744 void CompactibleFreeListSpace::save_marks() { | |
| 1745 // mark the "end" of the used space at the time of this call; | |
| 1746 // note, however, that promoted objects from this point | |
| 1747 // on are tracked in the _promoInfo below. | |
| 1748 set_saved_mark_word(BlockOffsetArrayUseUnallocatedBlock ? | |
| 1749 unallocated_block() : end()); | |
| 1750 // inform allocator that promotions should be tracked. | |
| 1751 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); | |
| 1752 _promoInfo.startTrackingPromotions(); | |
| 1753 } | |
| 1754 | |
| 1755 bool CompactibleFreeListSpace::no_allocs_since_save_marks() { | |
| 1756 assert(_promoInfo.tracking(), "No preceding save_marks?"); | |
| 1757 guarantee(SharedHeap::heap()->n_par_threads() == 0, | |
| 1758 "Shouldn't be called (yet) during parallel part of gc."); | |
| 1759 return _promoInfo.noPromotions(); | |
| 1760 } | |
| 1761 | |
| 1762 #define CFLS_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ | |
| 1763 \ | |
| 1764 void CompactibleFreeListSpace:: \ | |
| 1765 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ | |
| 1766 assert(SharedHeap::heap()->n_par_threads() == 0, \ | |
| 1767 "Shouldn't be called (yet) during parallel part of gc."); \ | |
| 1768 _promoInfo.promoted_oops_iterate##nv_suffix(blk); \ | |
| 1769 /* \ | |
| 1770 * This also restores any displaced headers and removes the elements from \ | |
| 1771 * the iteration set as they are processed, so that we have a clean slate \ | |
| 1772 * at the end of the iteration. Note, thus, that if new objects are \ | |
| 1773 * promoted as a result of the iteration they are iterated over as well. \ | |
| 1774 */ \ | |
| 1775 assert(_promoInfo.noPromotions(), "_promoInfo inconsistency"); \ | |
| 1776 } | |
| 1777 | |
| 1778 ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DEFN) | |
| 1779 | |
| 1780 ////////////////////////////////////////////////////////////////////////////// | |
| 1781 // We go over the list of promoted objects, removing each from the list, | |
| 1782 // and applying the closure (this may, in turn, add more elements to | |
| 1783 // the tail of the promoted list, and these newly added objects will | |
| 1784 // also be processed) until the list is empty. | |
| 1785 // To aid verification and debugging, in the non-product builds | |
| 1786 // we actually forward _promoHead each time we process a promoted oop. | |
| 1787 // Note that this is not necessary in general (i.e. when we don't need to | |
| 1788 // call PromotionInfo::verify()) because oop_iterate can only add to the | |
| 1789 // end of _promoTail, and never needs to look at _promoHead. | |
| 1790 | |
| 1791 #define PROMOTED_OOPS_ITERATE_DEFN(OopClosureType, nv_suffix) \ | |
| 1792 \ | |
| 1793 void PromotionInfo::promoted_oops_iterate##nv_suffix(OopClosureType* cl) { \ | |
| 1794 NOT_PRODUCT(verify()); \ | |
| 1795 PromotedObject *curObj, *nextObj; \ | |
| 1796 for (curObj = _promoHead; curObj != NULL; curObj = nextObj) { \ | |
| 1797 if ((nextObj = curObj->next()) == NULL) { \ | |
| 1798 /* protect ourselves against additions due to closure application \ | |
| 1799 below by resetting the list. */ \ | |
| 1800 assert(_promoTail == curObj, "Should have been the tail"); \ | |
| 1801 _promoHead = _promoTail = NULL; \ | |
| 1802 } \ | |
| 1803 if (curObj->hasDisplacedMark()) { \ | |
| 1804 /* restore displaced header */ \ | |
| 1805 oop(curObj)->set_mark(nextDisplacedHeader()); \ | |
| 1806 } else { \ | |
| 1807 /* restore prototypical header */ \ | |
| 1808 oop(curObj)->init_mark(); \ | |
| 1809 } \ | |
| 1810 /* The "promoted_mark" should now not be set */ \ | |
| 1811 assert(!curObj->hasPromotedMark(), \ | |
| 1812 "Should have been cleared by restoring displaced mark-word"); \ | |
| 1813 NOT_PRODUCT(_promoHead = nextObj); \ | |
| 1814 if (cl != NULL) oop(curObj)->oop_iterate(cl); \ | |
| 1815 if (nextObj == NULL) { /* start at head of list reset above */ \ | |
| 1816 nextObj = _promoHead; \ | |
| 1817 } \ | |
| 1818 } \ | |
| 1819 assert(noPromotions(), "post-condition violation"); \ | |
| 1820 assert(_promoHead == NULL && _promoTail == NULL, "emptied promoted list");\ | |
| 1821 assert(_spoolHead == _spoolTail, "emptied spooling buffers"); \ | |
| 1822 assert(_firstIndex == _nextIndex, "empty buffer"); \ | |
| 1823 } | |
| 1824 | |
| 1825 // This should have been ALL_SINCE_...() just like the others, | |
| 1826 // but, because the body of the method above is somehwat longer, | |
| 1827 // the MSVC compiler cannot cope; as a workaround, we split the | |
| 1828 // macro into its 3 constituent parts below (see original macro | |
| 1829 // definition in specializedOopClosures.hpp). | |
| 1830 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES_YOUNG(PROMOTED_OOPS_ITERATE_DEFN) | |
| 1831 PROMOTED_OOPS_ITERATE_DEFN(OopsInGenClosure,_v) | |
| 1832 | |
| 1833 | |
| 1834 void CompactibleFreeListSpace::object_iterate_since_last_GC(ObjectClosure* cl) { | |
| 1835 // ugghh... how would one do this efficiently for a non-contiguous space? | |
| 1836 guarantee(false, "NYI"); | |
| 1837 } | |
| 1838 | |
|
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1839 bool CompactibleFreeListSpace::linearAllocationWouldFail() const { |
| 0 | 1840 return _smallLinearAllocBlock._word_size == 0; |
| 1841 } | |
| 1842 | |
| 1843 void CompactibleFreeListSpace::repairLinearAllocationBlocks() { | |
| 1844 // Fix up linear allocation blocks to look like free blocks | |
| 1845 repairLinearAllocBlock(&_smallLinearAllocBlock); | |
| 1846 } | |
| 1847 | |
| 1848 void CompactibleFreeListSpace::repairLinearAllocBlock(LinearAllocBlock* blk) { | |
| 1849 assert_locked(); | |
| 1850 if (blk->_ptr != NULL) { | |
| 1851 assert(blk->_word_size != 0 && blk->_word_size >= MinChunkSize, | |
| 1852 "Minimum block size requirement"); | |
| 1853 FreeChunk* fc = (FreeChunk*)(blk->_ptr); | |
| 1854 fc->setSize(blk->_word_size); | |
| 1855 fc->linkPrev(NULL); // mark as free | |
| 1856 fc->dontCoalesce(); | |
| 1857 assert(fc->isFree(), "just marked it free"); | |
| 1858 assert(fc->cantCoalesce(), "just marked it uncoalescable"); | |
| 1859 } | |
| 1860 } | |
| 1861 | |
| 1862 void CompactibleFreeListSpace::refillLinearAllocBlocksIfNeeded() { | |
| 1863 assert_locked(); | |
| 1864 if (_smallLinearAllocBlock._ptr == NULL) { | |
| 1865 assert(_smallLinearAllocBlock._word_size == 0, | |
| 1866 "Size of linAB should be zero if the ptr is NULL"); | |
| 1867 // Reset the linAB refill and allocation size limit. | |
| 1868 _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, SmallForLinearAlloc); | |
| 1869 } | |
| 1870 refillLinearAllocBlockIfNeeded(&_smallLinearAllocBlock); | |
| 1871 } | |
| 1872 | |
| 1873 void | |
| 1874 CompactibleFreeListSpace::refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk) { | |
| 1875 assert_locked(); | |
| 1876 assert((blk->_ptr == NULL && blk->_word_size == 0) || | |
| 1877 (blk->_ptr != NULL && blk->_word_size >= MinChunkSize), | |
| 1878 "blk invariant"); | |
| 1879 if (blk->_ptr == NULL) { | |
| 1880 refillLinearAllocBlock(blk); | |
| 1881 } | |
| 1882 if (PrintMiscellaneous && Verbose) { | |
| 1883 if (blk->_word_size == 0) { | |
| 1884 warning("CompactibleFreeListSpace(prologue):: Linear allocation failure"); | |
| 1885 } | |
| 1886 } | |
| 1887 } | |
| 1888 | |
| 1889 void | |
| 1890 CompactibleFreeListSpace::refillLinearAllocBlock(LinearAllocBlock* blk) { | |
| 1891 assert_locked(); | |
| 1892 assert(blk->_word_size == 0 && blk->_ptr == NULL, | |
| 1893 "linear allocation block should be empty"); | |
| 1894 FreeChunk* fc; | |
| 1895 if (blk->_refillSize < SmallForDictionary && | |
| 1896 (fc = getChunkFromIndexedFreeList(blk->_refillSize)) != NULL) { | |
| 1897 // A linAB's strategy might be to use small sizes to reduce | |
| 1898 // fragmentation but still get the benefits of allocation from a | |
| 1899 // linAB. | |
| 1900 } else { | |
| 1901 fc = getChunkFromDictionary(blk->_refillSize); | |
| 1902 } | |
| 1903 if (fc != NULL) { | |
| 1904 blk->_ptr = (HeapWord*)fc; | |
| 1905 blk->_word_size = fc->size(); | |
| 1906 fc->dontCoalesce(); // to prevent sweeper from sweeping us up | |
| 1907 } | |
| 1908 } | |
| 1909 | |
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1910 // Support for concurrent collection policy decisions. |
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1911 bool CompactibleFreeListSpace::should_concurrent_collect() const { |
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1912 // In the future we might want to add in frgamentation stats -- |
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1913 // including erosion of the "mountain" into this decision as well. |
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1914 return !adaptive_freelists() && linearAllocationWouldFail(); |
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1915 } |
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1916 |
| 0 | 1917 // Support for compaction |
| 1918 | |
| 1919 void CompactibleFreeListSpace::prepare_for_compaction(CompactPoint* cp) { | |
| 1920 SCAN_AND_FORWARD(cp,end,block_is_obj,block_size); | |
| 1921 // prepare_for_compaction() uses the space between live objects | |
| 1922 // so that later phase can skip dead space quickly. So verification | |
| 1923 // of the free lists doesn't work after. | |
| 1924 } | |
| 1925 | |
| 1926 #define obj_size(q) adjustObjectSize(oop(q)->size()) | |
| 1927 #define adjust_obj_size(s) adjustObjectSize(s) | |
| 1928 | |
| 1929 void CompactibleFreeListSpace::adjust_pointers() { | |
| 1930 // In other versions of adjust_pointers(), a bail out | |
| 1931 // based on the amount of live data in the generation | |
| 1932 // (i.e., if 0, bail out) may be used. | |
| 1933 // Cannot test used() == 0 here because the free lists have already | |
| 1934 // been mangled by the compaction. | |
| 1935 | |
| 1936 SCAN_AND_ADJUST_POINTERS(adjust_obj_size); | |
| 1937 // See note about verification in prepare_for_compaction(). | |
| 1938 } | |
| 1939 | |
| 1940 void CompactibleFreeListSpace::compact() { | |
| 1941 SCAN_AND_COMPACT(obj_size); | |
| 1942 } | |
| 1943 | |
| 1944 // fragmentation_metric = 1 - [sum of (fbs**2) / (sum of fbs)**2] | |
| 1945 // where fbs is free block sizes | |
| 1946 double CompactibleFreeListSpace::flsFrag() const { | |
| 1947 size_t itabFree = totalSizeInIndexedFreeLists(); | |
| 1948 double frag = 0.0; | |
| 1949 size_t i; | |
| 1950 | |
| 1951 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 1952 double sz = i; | |
| 1953 frag += _indexedFreeList[i].count() * (sz * sz); | |
| 1954 } | |
| 1955 | |
| 1956 double totFree = itabFree + | |
| 1957 _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())); | |
| 1958 if (totFree > 0) { | |
| 1959 frag = ((frag + _dictionary->sum_of_squared_block_sizes()) / | |
| 1960 (totFree * totFree)); | |
| 1961 frag = (double)1.0 - frag; | |
| 1962 } else { | |
| 1963 assert(frag == 0.0, "Follows from totFree == 0"); | |
| 1964 } | |
| 1965 return frag; | |
| 1966 } | |
| 1967 | |
| 1968 #define CoalSurplusPercent 1.05 | |
| 1969 #define SplitSurplusPercent 1.10 | |
| 1970 | |
| 1971 void CompactibleFreeListSpace::beginSweepFLCensus( | |
| 1972 float inter_sweep_current, | |
| 1973 float inter_sweep_estimate) { | |
| 1974 assert_locked(); | |
| 1975 size_t i; | |
| 1976 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 1977 FreeList* fl = &_indexedFreeList[i]; | |
| 1978 fl->compute_desired(inter_sweep_current, inter_sweep_estimate); | |
| 1979 fl->set_coalDesired((ssize_t)((double)fl->desired() * CoalSurplusPercent)); | |
| 1980 fl->set_beforeSweep(fl->count()); | |
| 1981 fl->set_bfrSurp(fl->surplus()); | |
| 1982 } | |
| 1983 _dictionary->beginSweepDictCensus(CoalSurplusPercent, | |
| 1984 inter_sweep_current, | |
| 1985 inter_sweep_estimate); | |
| 1986 } | |
| 1987 | |
| 1988 void CompactibleFreeListSpace::setFLSurplus() { | |
| 1989 assert_locked(); | |
| 1990 size_t i; | |
| 1991 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 1992 FreeList *fl = &_indexedFreeList[i]; | |
| 1993 fl->set_surplus(fl->count() - | |
| 1994 (ssize_t)((double)fl->desired() * SplitSurplusPercent)); | |
| 1995 } | |
| 1996 } | |
| 1997 | |
| 1998 void CompactibleFreeListSpace::setFLHints() { | |
| 1999 assert_locked(); | |
| 2000 size_t i; | |
| 2001 size_t h = IndexSetSize; | |
| 2002 for (i = IndexSetSize - 1; i != 0; i -= IndexSetStride) { | |
| 2003 FreeList *fl = &_indexedFreeList[i]; | |
| 2004 fl->set_hint(h); | |
| 2005 if (fl->surplus() > 0) { | |
| 2006 h = i; | |
| 2007 } | |
| 2008 } | |
| 2009 } | |
| 2010 | |
| 2011 void CompactibleFreeListSpace::clearFLCensus() { | |
| 2012 assert_locked(); | |
| 2013 int i; | |
| 2014 for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2015 FreeList *fl = &_indexedFreeList[i]; | |
| 2016 fl->set_prevSweep(fl->count()); | |
| 2017 fl->set_coalBirths(0); | |
| 2018 fl->set_coalDeaths(0); | |
| 2019 fl->set_splitBirths(0); | |
| 2020 fl->set_splitDeaths(0); | |
| 2021 } | |
| 2022 } | |
| 2023 | |
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2024 void CompactibleFreeListSpace::endSweepFLCensus(size_t sweep_count) { |
| 0 | 2025 setFLSurplus(); |
| 2026 setFLHints(); | |
| 2027 if (PrintGC && PrintFLSCensus > 0) { | |
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2028 printFLCensus(sweep_count); |
| 0 | 2029 } |
| 2030 clearFLCensus(); | |
| 2031 assert_locked(); | |
| 2032 _dictionary->endSweepDictCensus(SplitSurplusPercent); | |
| 2033 } | |
| 2034 | |
| 2035 bool CompactibleFreeListSpace::coalOverPopulated(size_t size) { | |
| 2036 if (size < SmallForDictionary) { | |
| 2037 FreeList *fl = &_indexedFreeList[size]; | |
| 2038 return (fl->coalDesired() < 0) || | |
| 2039 ((int)fl->count() > fl->coalDesired()); | |
| 2040 } else { | |
| 2041 return dictionary()->coalDictOverPopulated(size); | |
| 2042 } | |
| 2043 } | |
| 2044 | |
| 2045 void CompactibleFreeListSpace::smallCoalBirth(size_t size) { | |
| 2046 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2047 FreeList *fl = &_indexedFreeList[size]; | |
| 2048 fl->increment_coalBirths(); | |
| 2049 fl->increment_surplus(); | |
| 2050 } | |
| 2051 | |
| 2052 void CompactibleFreeListSpace::smallCoalDeath(size_t size) { | |
| 2053 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2054 FreeList *fl = &_indexedFreeList[size]; | |
| 2055 fl->increment_coalDeaths(); | |
| 2056 fl->decrement_surplus(); | |
| 2057 } | |
| 2058 | |
| 2059 void CompactibleFreeListSpace::coalBirth(size_t size) { | |
| 2060 if (size < SmallForDictionary) { | |
| 2061 smallCoalBirth(size); | |
| 2062 } else { | |
| 2063 dictionary()->dictCensusUpdate(size, | |
| 2064 false /* split */, | |
| 2065 true /* birth */); | |
| 2066 } | |
| 2067 } | |
| 2068 | |
| 2069 void CompactibleFreeListSpace::coalDeath(size_t size) { | |
| 2070 if(size < SmallForDictionary) { | |
| 2071 smallCoalDeath(size); | |
| 2072 } else { | |
| 2073 dictionary()->dictCensusUpdate(size, | |
| 2074 false /* split */, | |
| 2075 false /* birth */); | |
| 2076 } | |
| 2077 } | |
| 2078 | |
| 2079 void CompactibleFreeListSpace::smallSplitBirth(size_t size) { | |
| 2080 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2081 FreeList *fl = &_indexedFreeList[size]; | |
| 2082 fl->increment_splitBirths(); | |
| 2083 fl->increment_surplus(); | |
| 2084 } | |
| 2085 | |
| 2086 void CompactibleFreeListSpace::smallSplitDeath(size_t size) { | |
| 2087 assert(size < SmallForDictionary, "Size too large for indexed list"); | |
| 2088 FreeList *fl = &_indexedFreeList[size]; | |
| 2089 fl->increment_splitDeaths(); | |
| 2090 fl->decrement_surplus(); | |
| 2091 } | |
| 2092 | |
| 2093 void CompactibleFreeListSpace::splitBirth(size_t size) { | |
| 2094 if (size < SmallForDictionary) { | |
| 2095 smallSplitBirth(size); | |
| 2096 } else { | |
| 2097 dictionary()->dictCensusUpdate(size, | |
| 2098 true /* split */, | |
| 2099 true /* birth */); | |
| 2100 } | |
| 2101 } | |
| 2102 | |
| 2103 void CompactibleFreeListSpace::splitDeath(size_t size) { | |
| 2104 if (size < SmallForDictionary) { | |
| 2105 smallSplitDeath(size); | |
| 2106 } else { | |
| 2107 dictionary()->dictCensusUpdate(size, | |
| 2108 true /* split */, | |
| 2109 false /* birth */); | |
| 2110 } | |
| 2111 } | |
| 2112 | |
| 2113 void CompactibleFreeListSpace::split(size_t from, size_t to1) { | |
| 2114 size_t to2 = from - to1; | |
| 2115 splitDeath(from); | |
| 2116 splitBirth(to1); | |
| 2117 splitBirth(to2); | |
| 2118 } | |
| 2119 | |
| 2120 void CompactibleFreeListSpace::print() const { | |
| 2121 tty->print(" CompactibleFreeListSpace"); | |
| 2122 Space::print(); | |
| 2123 } | |
| 2124 | |
| 2125 void CompactibleFreeListSpace::prepare_for_verify() { | |
| 2126 assert_locked(); | |
| 2127 repairLinearAllocationBlocks(); | |
| 2128 // Verify that the SpoolBlocks look like free blocks of | |
| 2129 // appropriate sizes... To be done ... | |
| 2130 } | |
| 2131 | |
| 2132 class VerifyAllBlksClosure: public BlkClosure { | |
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2133 private: |
| 0 | 2134 const CompactibleFreeListSpace* _sp; |
| 2135 const MemRegion _span; | |
| 2136 | |
| 2137 public: | |
| 2138 VerifyAllBlksClosure(const CompactibleFreeListSpace* sp, | |
| 2139 MemRegion span) : _sp(sp), _span(span) { } | |
| 2140 | |
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2141 virtual size_t do_blk(HeapWord* addr) { |
| 0 | 2142 size_t res; |
| 2143 if (_sp->block_is_obj(addr)) { | |
| 2144 oop p = oop(addr); | |
| 2145 guarantee(p->is_oop(), "Should be an oop"); | |
| 2146 res = _sp->adjustObjectSize(p->size()); | |
| 2147 if (_sp->obj_is_alive(addr)) { | |
| 2148 p->verify(); | |
| 2149 } | |
| 2150 } else { | |
| 2151 FreeChunk* fc = (FreeChunk*)addr; | |
| 2152 res = fc->size(); | |
| 2153 if (FLSVerifyLists && !fc->cantCoalesce()) { | |
| 2154 guarantee(_sp->verifyChunkInFreeLists(fc), | |
| 2155 "Chunk should be on a free list"); | |
| 2156 } | |
| 2157 } | |
| 2158 guarantee(res != 0, "Livelock: no rank reduction!"); | |
| 2159 return res; | |
| 2160 } | |
| 2161 }; | |
| 2162 | |
| 2163 class VerifyAllOopsClosure: public OopClosure { | |
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2164 private: |
| 0 | 2165 const CMSCollector* _collector; |
| 2166 const CompactibleFreeListSpace* _sp; | |
| 2167 const MemRegion _span; | |
| 2168 const bool _past_remark; | |
| 2169 const CMSBitMap* _bit_map; | |
| 2170 | |
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2171 protected: |
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2172 void do_oop(void* p, oop obj) { |
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2173 if (_span.contains(obj)) { // the interior oop points into CMS heap |
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2174 if (!_span.contains(p)) { // reference from outside CMS heap |
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2175 // Should be a valid object; the first disjunct below allows |
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2176 // us to sidestep an assertion in block_is_obj() that insists |
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2177 // that p be in _sp. Note that several generations (and spaces) |
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2178 // are spanned by _span (CMS heap) above. |
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2179 guarantee(!_sp->is_in_reserved(obj) || |
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2180 _sp->block_is_obj((HeapWord*)obj), |
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2181 "Should be an object"); |
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2182 guarantee(obj->is_oop(), "Should be an oop"); |
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2183 obj->verify(); |
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2184 if (_past_remark) { |
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2185 // Remark has been completed, the object should be marked |
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2186 _bit_map->isMarked((HeapWord*)obj); |
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2187 } |
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2188 } else { // reference within CMS heap |
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2189 if (_past_remark) { |
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2190 // Remark has been completed -- so the referent should have |
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2191 // been marked, if referring object is. |
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2192 if (_bit_map->isMarked(_collector->block_start(p))) { |
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2193 guarantee(_bit_map->isMarked((HeapWord*)obj), "Marking error?"); |
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2194 } |
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2195 } |
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2196 } |
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2197 } else if (_sp->is_in_reserved(p)) { |
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2198 // the reference is from FLS, and points out of FLS |
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2199 guarantee(obj->is_oop(), "Should be an oop"); |
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2200 obj->verify(); |
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2201 } |
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2202 } |
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2203 |
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2204 template <class T> void do_oop_work(T* p) { |
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2205 T heap_oop = oopDesc::load_heap_oop(p); |
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2206 if (!oopDesc::is_null(heap_oop)) { |
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2207 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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2208 do_oop(p, obj); |
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2209 } |
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2210 } |
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2211 |
| 0 | 2212 public: |
| 2213 VerifyAllOopsClosure(const CMSCollector* collector, | |
| 2214 const CompactibleFreeListSpace* sp, MemRegion span, | |
| 2215 bool past_remark, CMSBitMap* bit_map) : | |
| 2216 OopClosure(), _collector(collector), _sp(sp), _span(span), | |
| 2217 _past_remark(past_remark), _bit_map(bit_map) { } | |
| 2218 | |
|
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2219 virtual void do_oop(oop* p) { VerifyAllOopsClosure::do_oop_work(p); } |
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2220 virtual void do_oop(narrowOop* p) { VerifyAllOopsClosure::do_oop_work(p); } |
| 0 | 2221 }; |
| 2222 | |
| 2223 void CompactibleFreeListSpace::verify(bool ignored) const { | |
| 2224 assert_lock_strong(&_freelistLock); | |
| 2225 verify_objects_initialized(); | |
| 2226 MemRegion span = _collector->_span; | |
| 2227 bool past_remark = (_collector->abstract_state() == | |
| 2228 CMSCollector::Sweeping); | |
| 2229 | |
| 2230 ResourceMark rm; | |
| 2231 HandleMark hm; | |
| 2232 | |
| 2233 // Check integrity of CFL data structures | |
| 2234 _promoInfo.verify(); | |
| 2235 _dictionary->verify(); | |
| 2236 if (FLSVerifyIndexTable) { | |
| 2237 verifyIndexedFreeLists(); | |
| 2238 } | |
| 2239 // Check integrity of all objects and free blocks in space | |
| 2240 { | |
| 2241 VerifyAllBlksClosure cl(this, span); | |
| 2242 ((CompactibleFreeListSpace*)this)->blk_iterate(&cl); // cast off const | |
| 2243 } | |
| 2244 // Check that all references in the heap to FLS | |
| 2245 // are to valid objects in FLS or that references in | |
| 2246 // FLS are to valid objects elsewhere in the heap | |
| 2247 if (FLSVerifyAllHeapReferences) | |
| 2248 { | |
| 2249 VerifyAllOopsClosure cl(_collector, this, span, past_remark, | |
| 2250 _collector->markBitMap()); | |
| 2251 CollectedHeap* ch = Universe::heap(); | |
| 2252 ch->oop_iterate(&cl); // all oops in generations | |
| 2253 ch->permanent_oop_iterate(&cl); // all oops in perm gen | |
| 2254 } | |
| 2255 | |
| 2256 if (VerifyObjectStartArray) { | |
| 2257 // Verify the block offset table | |
| 2258 _bt.verify(); | |
| 2259 } | |
| 2260 } | |
| 2261 | |
| 2262 #ifndef PRODUCT | |
| 2263 void CompactibleFreeListSpace::verifyFreeLists() const { | |
| 2264 if (FLSVerifyLists) { | |
| 2265 _dictionary->verify(); | |
| 2266 verifyIndexedFreeLists(); | |
| 2267 } else { | |
| 2268 if (FLSVerifyDictionary) { | |
| 2269 _dictionary->verify(); | |
| 2270 } | |
| 2271 if (FLSVerifyIndexTable) { | |
| 2272 verifyIndexedFreeLists(); | |
| 2273 } | |
| 2274 } | |
| 2275 } | |
| 2276 #endif | |
| 2277 | |
| 2278 void CompactibleFreeListSpace::verifyIndexedFreeLists() const { | |
| 2279 size_t i = 0; | |
| 2280 for (; i < MinChunkSize; i++) { | |
| 2281 guarantee(_indexedFreeList[i].head() == NULL, "should be NULL"); | |
| 2282 } | |
| 2283 for (; i < IndexSetSize; i++) { | |
| 2284 verifyIndexedFreeList(i); | |
| 2285 } | |
| 2286 } | |
| 2287 | |
| 2288 void CompactibleFreeListSpace::verifyIndexedFreeList(size_t size) const { | |
| 2289 guarantee(size % 2 == 0, "Odd slots should be empty"); | |
| 2290 for (FreeChunk* fc = _indexedFreeList[size].head(); fc != NULL; | |
| 2291 fc = fc->next()) { | |
| 2292 guarantee(fc->size() == size, "Size inconsistency"); | |
| 2293 guarantee(fc->isFree(), "!free?"); | |
| 2294 guarantee(fc->next() == NULL || fc->next()->prev() == fc, "Broken list"); | |
| 2295 } | |
| 2296 } | |
| 2297 | |
| 2298 #ifndef PRODUCT | |
| 2299 void CompactibleFreeListSpace::checkFreeListConsistency() const { | |
| 2300 assert(_dictionary->minSize() <= IndexSetSize, | |
| 2301 "Some sizes can't be allocated without recourse to" | |
| 2302 " linear allocation buffers"); | |
| 2303 assert(MIN_TREE_CHUNK_SIZE*HeapWordSize == sizeof(TreeChunk), | |
| 2304 "else MIN_TREE_CHUNK_SIZE is wrong"); | |
| 2305 assert((IndexSetStride == 2 && IndexSetStart == 2) || | |
| 2306 (IndexSetStride == 1 && IndexSetStart == 1), "just checking"); | |
| 2307 assert((IndexSetStride != 2) || (MinChunkSize % 2 == 0), | |
| 2308 "Some for-loops may be incorrectly initialized"); | |
| 2309 assert((IndexSetStride != 2) || (IndexSetSize % 2 == 1), | |
| 2310 "For-loops that iterate over IndexSet with stride 2 may be wrong"); | |
| 2311 } | |
| 2312 #endif | |
| 2313 | |
|
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2314 void CompactibleFreeListSpace::printFLCensus(size_t sweep_count) const { |
| 0 | 2315 assert_lock_strong(&_freelistLock); |
|
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2316 FreeList total; |
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2317 gclog_or_tty->print("end sweep# " SIZE_FORMAT "\n", sweep_count); |
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2318 FreeList::print_labels_on(gclog_or_tty, "size"); |
| 0 | 2319 size_t totalFree = 0; |
| 2320 for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) { | |
| 2321 const FreeList *fl = &_indexedFreeList[i]; | |
|
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2322 totalFree += fl->count() * fl->size(); |
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2323 if (i % (40*IndexSetStride) == 0) { |
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2324 FreeList::print_labels_on(gclog_or_tty, "size"); |
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2325 } |
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2326 fl->print_on(gclog_or_tty); |
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2327 total.set_bfrSurp( total.bfrSurp() + fl->bfrSurp() ); |
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2328 total.set_surplus( total.surplus() + fl->surplus() ); |
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2329 total.set_desired( total.desired() + fl->desired() ); |
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2330 total.set_prevSweep( total.prevSweep() + fl->prevSweep() ); |
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2331 total.set_beforeSweep(total.beforeSweep() + fl->beforeSweep()); |
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2332 total.set_count( total.count() + fl->count() ); |
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2333 total.set_coalBirths( total.coalBirths() + fl->coalBirths() ); |
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2334 total.set_coalDeaths( total.coalDeaths() + fl->coalDeaths() ); |
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2335 total.set_splitBirths(total.splitBirths() + fl->splitBirths()); |
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2336 total.set_splitDeaths(total.splitDeaths() + fl->splitDeaths()); |
| 0 | 2337 } |
|
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2338 total.print_on(gclog_or_tty, "TOTAL"); |
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2339 gclog_or_tty->print_cr("Total free in indexed lists " |
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2340 SIZE_FORMAT " words", totalFree); |
| 0 | 2341 gclog_or_tty->print("growth: %8.5f deficit: %8.5f\n", |
|
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2342 (double)(total.splitBirths()+total.coalBirths()-total.splitDeaths()-total.coalDeaths())/ |
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2343 (total.prevSweep() != 0 ? (double)total.prevSweep() : 1.0), |
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2344 (double)(total.desired() - total.count())/(total.desired() != 0 ? (double)total.desired() : 1.0)); |
| 0 | 2345 _dictionary->printDictCensus(); |
| 2346 } | |
| 2347 | |
| 2348 // Return the next displaced header, incrementing the pointer and | |
| 2349 // recycling spool area as necessary. | |
| 2350 markOop PromotionInfo::nextDisplacedHeader() { | |
| 2351 assert(_spoolHead != NULL, "promotionInfo inconsistency"); | |
| 2352 assert(_spoolHead != _spoolTail || _firstIndex < _nextIndex, | |
| 2353 "Empty spool space: no displaced header can be fetched"); | |
| 2354 assert(_spoolHead->bufferSize > _firstIndex, "Off by one error at head?"); | |
| 2355 markOop hdr = _spoolHead->displacedHdr[_firstIndex]; | |
| 2356 // Spool forward | |
| 2357 if (++_firstIndex == _spoolHead->bufferSize) { // last location in this block | |
| 2358 // forward to next block, recycling this block into spare spool buffer | |
| 2359 SpoolBlock* tmp = _spoolHead->nextSpoolBlock; | |
| 2360 assert(_spoolHead != _spoolTail, "Spooling storage mix-up"); | |
| 2361 _spoolHead->nextSpoolBlock = _spareSpool; | |
| 2362 _spareSpool = _spoolHead; | |
| 2363 _spoolHead = tmp; | |
| 2364 _firstIndex = 1; | |
| 2365 NOT_PRODUCT( | |
| 2366 if (_spoolHead == NULL) { // all buffers fully consumed | |
| 2367 assert(_spoolTail == NULL && _nextIndex == 1, | |
| 2368 "spool buffers processing inconsistency"); | |
| 2369 } | |
| 2370 ) | |
| 2371 } | |
| 2372 return hdr; | |
| 2373 } | |
| 2374 | |
| 2375 void PromotionInfo::track(PromotedObject* trackOop) { | |
| 2376 track(trackOop, oop(trackOop)->klass()); | |
| 2377 } | |
| 2378 | |
| 2379 void PromotionInfo::track(PromotedObject* trackOop, klassOop klassOfOop) { | |
| 2380 // make a copy of header as it may need to be spooled | |
| 2381 markOop mark = oop(trackOop)->mark(); | |
| 2382 trackOop->clearNext(); | |
| 2383 if (mark->must_be_preserved_for_cms_scavenge(klassOfOop)) { | |
| 2384 // save non-prototypical header, and mark oop | |
| 2385 saveDisplacedHeader(mark); | |
| 2386 trackOop->setDisplacedMark(); | |
| 2387 } else { | |
| 2388 // we'd like to assert something like the following: | |
| 2389 // assert(mark == markOopDesc::prototype(), "consistency check"); | |
| 2390 // ... but the above won't work because the age bits have not (yet) been | |
| 2391 // cleared. The remainder of the check would be identical to the | |
| 2392 // condition checked in must_be_preserved() above, so we don't really | |
| 2393 // have anything useful to check here! | |
| 2394 } | |
| 2395 if (_promoTail != NULL) { | |
| 2396 assert(_promoHead != NULL, "List consistency"); | |
| 2397 _promoTail->setNext(trackOop); | |
| 2398 _promoTail = trackOop; | |
| 2399 } else { | |
| 2400 assert(_promoHead == NULL, "List consistency"); | |
| 2401 _promoHead = _promoTail = trackOop; | |
| 2402 } | |
| 2403 // Mask as newly promoted, so we can skip over such objects | |
| 2404 // when scanning dirty cards | |
| 2405 assert(!trackOop->hasPromotedMark(), "Should not have been marked"); | |
| 2406 trackOop->setPromotedMark(); | |
| 2407 } | |
| 2408 | |
| 2409 // Save the given displaced header, incrementing the pointer and | |
| 2410 // obtaining more spool area as necessary. | |
| 2411 void PromotionInfo::saveDisplacedHeader(markOop hdr) { | |
| 2412 assert(_spoolHead != NULL && _spoolTail != NULL, | |
| 2413 "promotionInfo inconsistency"); | |
| 2414 assert(_spoolTail->bufferSize > _nextIndex, "Off by one error at tail?"); | |
| 2415 _spoolTail->displacedHdr[_nextIndex] = hdr; | |
| 2416 // Spool forward | |
| 2417 if (++_nextIndex == _spoolTail->bufferSize) { // last location in this block | |
| 2418 // get a new spooling block | |
| 2419 assert(_spoolTail->nextSpoolBlock == NULL, "tail should terminate spool list"); | |
| 2420 _splice_point = _spoolTail; // save for splicing | |
| 2421 _spoolTail->nextSpoolBlock = getSpoolBlock(); // might fail | |
| 2422 _spoolTail = _spoolTail->nextSpoolBlock; // might become NULL ... | |
| 2423 // ... but will attempt filling before next promotion attempt | |
| 2424 _nextIndex = 1; | |
| 2425 } | |
| 2426 } | |
| 2427 | |
| 2428 // Ensure that spooling space exists. Return false if spooling space | |
| 2429 // could not be obtained. | |
| 2430 bool PromotionInfo::ensure_spooling_space_work() { | |
| 2431 assert(!has_spooling_space(), "Only call when there is no spooling space"); | |
| 2432 // Try and obtain more spooling space | |
| 2433 SpoolBlock* newSpool = getSpoolBlock(); | |
| 2434 assert(newSpool == NULL || | |
| 2435 (newSpool->bufferSize != 0 && newSpool->nextSpoolBlock == NULL), | |
| 2436 "getSpoolBlock() sanity check"); | |
| 2437 if (newSpool == NULL) { | |
| 2438 return false; | |
| 2439 } | |
| 2440 _nextIndex = 1; | |
| 2441 if (_spoolTail == NULL) { | |
| 2442 _spoolTail = newSpool; | |
| 2443 if (_spoolHead == NULL) { | |
| 2444 _spoolHead = newSpool; | |
| 2445 _firstIndex = 1; | |
| 2446 } else { | |
| 2447 assert(_splice_point != NULL && _splice_point->nextSpoolBlock == NULL, | |
| 2448 "Splice point invariant"); | |
| 2449 // Extra check that _splice_point is connected to list | |
| 2450 #ifdef ASSERT | |
| 2451 { | |
| 2452 SpoolBlock* blk = _spoolHead; | |
| 2453 for (; blk->nextSpoolBlock != NULL; | |
| 2454 blk = blk->nextSpoolBlock); | |
| 2455 assert(blk != NULL && blk == _splice_point, | |
| 2456 "Splice point incorrect"); | |
| 2457 } | |
| 2458 #endif // ASSERT | |
| 2459 _splice_point->nextSpoolBlock = newSpool; | |
| 2460 } | |
| 2461 } else { | |
| 2462 assert(_spoolHead != NULL, "spool list consistency"); | |
| 2463 _spoolTail->nextSpoolBlock = newSpool; | |
| 2464 _spoolTail = newSpool; | |
| 2465 } | |
| 2466 return true; | |
| 2467 } | |
| 2468 | |
| 2469 // Get a free spool buffer from the free pool, getting a new block | |
| 2470 // from the heap if necessary. | |
| 2471 SpoolBlock* PromotionInfo::getSpoolBlock() { | |
| 2472 SpoolBlock* res; | |
| 2473 if ((res = _spareSpool) != NULL) { | |
| 2474 _spareSpool = _spareSpool->nextSpoolBlock; | |
| 2475 res->nextSpoolBlock = NULL; | |
| 2476 } else { // spare spool exhausted, get some from heap | |
| 2477 res = (SpoolBlock*)(space()->allocateScratch(refillSize())); | |
| 2478 if (res != NULL) { | |
| 2479 res->init(); | |
| 2480 } | |
| 2481 } | |
| 2482 assert(res == NULL || res->nextSpoolBlock == NULL, "postcondition"); | |
| 2483 return res; | |
| 2484 } | |
| 2485 | |
| 2486 void PromotionInfo::startTrackingPromotions() { | |
| 2487 assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, | |
| 2488 "spooling inconsistency?"); | |
| 2489 _firstIndex = _nextIndex = 1; | |
| 2490 _tracking = true; | |
| 2491 } | |
| 2492 | |
| 2493 void PromotionInfo::stopTrackingPromotions() { | |
| 2494 assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, | |
| 2495 "spooling inconsistency?"); | |
| 2496 _firstIndex = _nextIndex = 1; | |
| 2497 _tracking = false; | |
| 2498 } | |
| 2499 | |
| 2500 // When _spoolTail is not NULL, then the slot <_spoolTail, _nextIndex> | |
| 2501 // points to the next slot available for filling. | |
| 2502 // The set of slots holding displaced headers are then all those in the | |
| 2503 // right-open interval denoted by: | |
| 2504 // | |
| 2505 // [ <_spoolHead, _firstIndex>, <_spoolTail, _nextIndex> ) | |
| 2506 // | |
| 2507 // When _spoolTail is NULL, then the set of slots with displaced headers | |
| 2508 // is all those starting at the slot <_spoolHead, _firstIndex> and | |
| 2509 // going up to the last slot of last block in the linked list. | |
| 2510 // In this lartter case, _splice_point points to the tail block of | |
| 2511 // this linked list of blocks holding displaced headers. | |
| 2512 void PromotionInfo::verify() const { | |
| 2513 // Verify the following: | |
| 2514 // 1. the number of displaced headers matches the number of promoted | |
| 2515 // objects that have displaced headers | |
| 2516 // 2. each promoted object lies in this space | |
| 2517 debug_only( | |
| 2518 PromotedObject* junk = NULL; | |
| 2519 assert(junk->next_addr() == (void*)(oop(junk)->mark_addr()), | |
| 2520 "Offset of PromotedObject::_next is expected to align with " | |
| 2521 " the OopDesc::_mark within OopDesc"); | |
| 2522 ) | |
| 2523 // FIXME: guarantee???? | |
| 2524 guarantee(_spoolHead == NULL || _spoolTail != NULL || | |
| 2525 _splice_point != NULL, "list consistency"); | |
| 2526 guarantee(_promoHead == NULL || _promoTail != NULL, "list consistency"); | |
| 2527 // count the number of objects with displaced headers | |
| 2528 size_t numObjsWithDisplacedHdrs = 0; | |
| 2529 for (PromotedObject* curObj = _promoHead; curObj != NULL; curObj = curObj->next()) { | |
| 2530 guarantee(space()->is_in_reserved((HeapWord*)curObj), "Containment"); | |
| 2531 // the last promoted object may fail the mark() != NULL test of is_oop(). | |
| 2532 guarantee(curObj->next() == NULL || oop(curObj)->is_oop(), "must be an oop"); | |
| 2533 if (curObj->hasDisplacedMark()) { | |
| 2534 numObjsWithDisplacedHdrs++; | |
| 2535 } | |
| 2536 } | |
| 2537 // Count the number of displaced headers | |
| 2538 size_t numDisplacedHdrs = 0; | |
| 2539 for (SpoolBlock* curSpool = _spoolHead; | |
| 2540 curSpool != _spoolTail && curSpool != NULL; | |
| 2541 curSpool = curSpool->nextSpoolBlock) { | |
| 2542 // the first entry is just a self-pointer; indices 1 through | |
| 2543 // bufferSize - 1 are occupied (thus, bufferSize - 1 slots). | |
| 2544 guarantee((void*)curSpool->displacedHdr == (void*)&curSpool->displacedHdr, | |
| 2545 "first entry of displacedHdr should be self-referential"); | |
| 2546 numDisplacedHdrs += curSpool->bufferSize - 1; | |
| 2547 } | |
| 2548 guarantee((_spoolHead == _spoolTail) == (numDisplacedHdrs == 0), | |
| 2549 "internal consistency"); | |
| 2550 guarantee(_spoolTail != NULL || _nextIndex == 1, | |
| 2551 "Inconsistency between _spoolTail and _nextIndex"); | |
| 2552 // We overcounted (_firstIndex-1) worth of slots in block | |
| 2553 // _spoolHead and we undercounted (_nextIndex-1) worth of | |
| 2554 // slots in block _spoolTail. We make an appropriate | |
| 2555 // adjustment by subtracting the first and adding the | |
| 2556 // second: - (_firstIndex - 1) + (_nextIndex - 1) | |
| 2557 numDisplacedHdrs += (_nextIndex - _firstIndex); | |
| 2558 guarantee(numDisplacedHdrs == numObjsWithDisplacedHdrs, "Displaced hdr count"); | |
| 2559 } | |
| 2560 | |
| 2561 | |
| 2562 CFLS_LAB::CFLS_LAB(CompactibleFreeListSpace* cfls) : | |
| 2563 _cfls(cfls) | |
| 2564 { | |
| 2565 _blocks_to_claim = CMSParPromoteBlocksToClaim; | |
| 2566 for (size_t i = CompactibleFreeListSpace::IndexSetStart; | |
| 2567 i < CompactibleFreeListSpace::IndexSetSize; | |
| 2568 i += CompactibleFreeListSpace::IndexSetStride) { | |
| 2569 _indexedFreeList[i].set_size(i); | |
| 2570 } | |
| 2571 } | |
| 2572 | |
| 2573 HeapWord* CFLS_LAB::alloc(size_t word_sz) { | |
| 2574 FreeChunk* res; | |
| 2575 word_sz = _cfls->adjustObjectSize(word_sz); | |
| 2576 if (word_sz >= CompactibleFreeListSpace::IndexSetSize) { | |
| 2577 // This locking manages sync with other large object allocations. | |
| 2578 MutexLockerEx x(_cfls->parDictionaryAllocLock(), | |
| 2579 Mutex::_no_safepoint_check_flag); | |
| 2580 res = _cfls->getChunkFromDictionaryExact(word_sz); | |
| 2581 if (res == NULL) return NULL; | |
| 2582 } else { | |
| 2583 FreeList* fl = &_indexedFreeList[word_sz]; | |
| 2584 bool filled = false; //TRAP | |
| 2585 if (fl->count() == 0) { | |
| 2586 bool filled = true; //TRAP | |
| 2587 // Attempt to refill this local free list. | |
| 2588 _cfls->par_get_chunk_of_blocks(word_sz, _blocks_to_claim, fl); | |
| 2589 // If it didn't work, give up. | |
| 2590 if (fl->count() == 0) return NULL; | |
| 2591 } | |
| 2592 res = fl->getChunkAtHead(); | |
| 2593 assert(res != NULL, "Why was count non-zero?"); | |
| 2594 } | |
| 2595 res->markNotFree(); | |
| 2596 assert(!res->isFree(), "shouldn't be marked free"); | |
| 187 | 2597 assert(oop(res)->klass_or_null() == NULL, "should look uninitialized"); |
| 0 | 2598 // mangle a just allocated object with a distinct pattern. |
| 2599 debug_only(res->mangleAllocated(word_sz)); | |
| 2600 return (HeapWord*)res; | |
| 2601 } | |
| 2602 | |
| 2603 void CFLS_LAB::retire() { | |
| 2604 for (size_t i = CompactibleFreeListSpace::IndexSetStart; | |
| 2605 i < CompactibleFreeListSpace::IndexSetSize; | |
| 2606 i += CompactibleFreeListSpace::IndexSetStride) { | |
| 2607 if (_indexedFreeList[i].count() > 0) { | |
| 2608 MutexLockerEx x(_cfls->_indexedFreeListParLocks[i], | |
| 2609 Mutex::_no_safepoint_check_flag); | |
| 2610 _cfls->_indexedFreeList[i].prepend(&_indexedFreeList[i]); | |
| 2611 // Reset this list. | |
| 2612 _indexedFreeList[i] = FreeList(); | |
| 2613 _indexedFreeList[i].set_size(i); | |
| 2614 } | |
| 2615 } | |
| 2616 } | |
| 2617 | |
| 2618 void | |
| 2619 CompactibleFreeListSpace:: | |
| 2620 par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl) { | |
| 2621 assert(fl->count() == 0, "Precondition."); | |
| 2622 assert(word_sz < CompactibleFreeListSpace::IndexSetSize, | |
| 2623 "Precondition"); | |
| 2624 | |
| 2625 // We'll try all multiples of word_sz in the indexed set (starting with | |
| 2626 // word_sz itself), then try getting a big chunk and splitting it. | |
| 2627 int k = 1; | |
| 2628 size_t cur_sz = k * word_sz; | |
| 2629 bool found = false; | |
| 2630 while (cur_sz < CompactibleFreeListSpace::IndexSetSize && k == 1) { | |
| 2631 FreeList* gfl = &_indexedFreeList[cur_sz]; | |
| 2632 FreeList fl_for_cur_sz; // Empty. | |
| 2633 fl_for_cur_sz.set_size(cur_sz); | |
| 2634 { | |
| 2635 MutexLockerEx x(_indexedFreeListParLocks[cur_sz], | |
| 2636 Mutex::_no_safepoint_check_flag); | |
| 2637 if (gfl->count() != 0) { | |
| 2638 size_t nn = MAX2(n/k, (size_t)1); | |
| 2639 gfl->getFirstNChunksFromList(nn, &fl_for_cur_sz); | |
| 2640 found = true; | |
| 2641 } | |
| 2642 } | |
| 2643 // Now transfer fl_for_cur_sz to fl. Common case, we hope, is k = 1. | |
| 2644 if (found) { | |
| 2645 if (k == 1) { | |
| 2646 fl->prepend(&fl_for_cur_sz); | |
| 2647 } else { | |
| 2648 // Divide each block on fl_for_cur_sz up k ways. | |
| 2649 FreeChunk* fc; | |
| 2650 while ((fc = fl_for_cur_sz.getChunkAtHead()) != NULL) { | |
| 2651 // Must do this in reverse order, so that anybody attempting to | |
| 2652 // access the main chunk sees it as a single free block until we | |
| 2653 // change it. | |
| 2654 size_t fc_size = fc->size(); | |
| 2655 for (int i = k-1; i >= 0; i--) { | |
| 2656 FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz); | |
| 2657 ffc->setSize(word_sz); | |
| 2658 ffc->linkNext(NULL); | |
| 2659 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. | |
| 2660 // Above must occur before BOT is updated below. | |
| 2661 // splitting from the right, fc_size == (k - i + 1) * wordsize | |
| 2662 _bt.mark_block((HeapWord*)ffc, word_sz); | |
| 2663 fc_size -= word_sz; | |
| 2664 _bt.verify_not_unallocated((HeapWord*)ffc, ffc->size()); | |
| 2665 _bt.verify_single_block((HeapWord*)fc, fc_size); | |
| 2666 _bt.verify_single_block((HeapWord*)ffc, ffc->size()); | |
| 2667 // Push this on "fl". | |
| 2668 fl->returnChunkAtHead(ffc); | |
| 2669 } | |
| 2670 // TRAP | |
| 2671 assert(fl->tail()->next() == NULL, "List invariant."); | |
| 2672 } | |
| 2673 } | |
| 2674 return; | |
| 2675 } | |
| 2676 k++; cur_sz = k * word_sz; | |
| 2677 } | |
| 2678 // Otherwise, we'll split a block from the dictionary. | |
| 2679 FreeChunk* fc = NULL; | |
| 2680 FreeChunk* rem_fc = NULL; | |
| 2681 size_t rem; | |
| 2682 { | |
| 2683 MutexLockerEx x(parDictionaryAllocLock(), | |
| 2684 Mutex::_no_safepoint_check_flag); | |
| 2685 while (n > 0) { | |
| 2686 fc = dictionary()->getChunk(MAX2(n * word_sz, | |
| 2687 _dictionary->minSize()), | |
| 2688 FreeBlockDictionary::atLeast); | |
| 2689 if (fc != NULL) { | |
| 2690 _bt.allocated((HeapWord*)fc, fc->size()); // update _unallocated_blk | |
| 2691 dictionary()->dictCensusUpdate(fc->size(), | |
| 2692 true /*split*/, | |
| 2693 false /*birth*/); | |
| 2694 break; | |
| 2695 } else { | |
| 2696 n--; | |
| 2697 } | |
| 2698 } | |
| 2699 if (fc == NULL) return; | |
| 2700 // Otherwise, split up that block. | |
| 2701 size_t nn = fc->size() / word_sz; | |
| 2702 n = MIN2(nn, n); | |
| 2703 rem = fc->size() - n * word_sz; | |
| 2704 // If there is a remainder, and it's too small, allocate one fewer. | |
| 2705 if (rem > 0 && rem < MinChunkSize) { | |
| 2706 n--; rem += word_sz; | |
| 2707 } | |
| 2708 // First return the remainder, if any. | |
| 2709 // Note that we hold the lock until we decide if we're going to give | |
| 2710 // back the remainder to the dictionary, since a contending allocator | |
| 2711 // may otherwise see the heap as empty. (We're willing to take that | |
| 2712 // hit if the block is a small block.) | |
| 2713 if (rem > 0) { | |
| 2714 size_t prefix_size = n * word_sz; | |
| 2715 rem_fc = (FreeChunk*)((HeapWord*)fc + prefix_size); | |
| 2716 rem_fc->setSize(rem); | |
| 2717 rem_fc->linkNext(NULL); | |
| 2718 rem_fc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. | |
| 2719 // Above must occur before BOT is updated below. | |
| 2720 _bt.split_block((HeapWord*)fc, fc->size(), prefix_size); | |
| 2721 if (rem >= IndexSetSize) { | |
| 2722 returnChunkToDictionary(rem_fc); | |
| 2723 dictionary()->dictCensusUpdate(fc->size(), | |
| 2724 true /*split*/, | |
| 2725 true /*birth*/); | |
| 2726 rem_fc = NULL; | |
| 2727 } | |
| 2728 // Otherwise, return it to the small list below. | |
| 2729 } | |
| 2730 } | |
| 2731 // | |
| 2732 if (rem_fc != NULL) { | |
| 2733 MutexLockerEx x(_indexedFreeListParLocks[rem], | |
| 2734 Mutex::_no_safepoint_check_flag); | |
| 2735 _bt.verify_not_unallocated((HeapWord*)rem_fc, rem_fc->size()); | |
| 2736 _indexedFreeList[rem].returnChunkAtHead(rem_fc); | |
| 2737 smallSplitBirth(rem); | |
| 2738 } | |
| 2739 | |
| 2740 // Now do the splitting up. | |
| 2741 // Must do this in reverse order, so that anybody attempting to | |
| 2742 // access the main chunk sees it as a single free block until we | |
| 2743 // change it. | |
| 2744 size_t fc_size = n * word_sz; | |
| 2745 // All but first chunk in this loop | |
| 2746 for (ssize_t i = n-1; i > 0; i--) { | |
| 2747 FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz); | |
| 2748 ffc->setSize(word_sz); | |
| 2749 ffc->linkNext(NULL); | |
| 2750 ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads. | |
| 2751 // Above must occur before BOT is updated below. | |
| 2752 // splitting from the right, fc_size == (n - i + 1) * wordsize | |
| 2753 _bt.mark_block((HeapWord*)ffc, word_sz); | |
| 2754 fc_size -= word_sz; | |
| 2755 _bt.verify_not_unallocated((HeapWord*)ffc, ffc->size()); | |
| 2756 _bt.verify_single_block((HeapWord*)ffc, ffc->size()); | |
| 2757 _bt.verify_single_block((HeapWord*)fc, fc_size); | |
| 2758 // Push this on "fl". | |
| 2759 fl->returnChunkAtHead(ffc); | |
| 2760 } | |
| 2761 // First chunk | |
| 2762 fc->setSize(word_sz); | |
| 2763 fc->linkNext(NULL); | |
| 2764 fc->linkPrev(NULL); | |
| 2765 _bt.verify_not_unallocated((HeapWord*)fc, fc->size()); | |
| 2766 _bt.verify_single_block((HeapWord*)fc, fc->size()); | |
| 2767 fl->returnChunkAtHead(fc); | |
| 2768 | |
| 2769 { | |
| 2770 MutexLockerEx x(_indexedFreeListParLocks[word_sz], | |
| 2771 Mutex::_no_safepoint_check_flag); | |
| 2772 ssize_t new_births = _indexedFreeList[word_sz].splitBirths() + n; | |
| 2773 _indexedFreeList[word_sz].set_splitBirths(new_births); | |
| 2774 ssize_t new_surplus = _indexedFreeList[word_sz].surplus() + n; | |
| 2775 _indexedFreeList[word_sz].set_surplus(new_surplus); | |
| 2776 } | |
| 2777 | |
| 2778 // TRAP | |
| 2779 assert(fl->tail()->next() == NULL, "List invariant."); | |
| 2780 } | |
| 2781 | |
| 2782 // Set up the space's par_seq_tasks structure for work claiming | |
| 2783 // for parallel rescan. See CMSParRemarkTask where this is currently used. | |
| 2784 // XXX Need to suitably abstract and generalize this and the next | |
| 2785 // method into one. | |
| 2786 void | |
| 2787 CompactibleFreeListSpace:: | |
| 2788 initialize_sequential_subtasks_for_rescan(int n_threads) { | |
| 2789 // The "size" of each task is fixed according to rescan_task_size. | |
| 2790 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 2791 const size_t task_size = rescan_task_size(); | |
| 2792 size_t n_tasks = (used_region().word_size() + task_size - 1)/task_size; | |
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2793 assert((n_tasks == 0) == used_region().is_empty(), "n_tasks incorrect"); |
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2794 assert(n_tasks == 0 || |
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2795 ((used_region().start() + (n_tasks - 1)*task_size < used_region().end()) && |
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2796 (used_region().start() + n_tasks*task_size >= used_region().end())), |
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2797 "n_tasks calculation incorrect"); |
| 0 | 2798 SequentialSubTasksDone* pst = conc_par_seq_tasks(); |
| 2799 assert(!pst->valid(), "Clobbering existing data?"); | |
| 2800 pst->set_par_threads(n_threads); | |
| 2801 pst->set_n_tasks((int)n_tasks); | |
| 2802 } | |
| 2803 | |
| 2804 // Set up the space's par_seq_tasks structure for work claiming | |
| 2805 // for parallel concurrent marking. See CMSConcMarkTask where this is currently used. | |
| 2806 void | |
| 2807 CompactibleFreeListSpace:: | |
| 2808 initialize_sequential_subtasks_for_marking(int n_threads, | |
| 2809 HeapWord* low) { | |
| 2810 // The "size" of each task is fixed according to rescan_task_size. | |
| 2811 assert(n_threads > 0, "Unexpected n_threads argument"); | |
| 2812 const size_t task_size = marking_task_size(); | |
| 2813 assert(task_size > CardTableModRefBS::card_size_in_words && | |
| 2814 (task_size % CardTableModRefBS::card_size_in_words == 0), | |
| 2815 "Otherwise arithmetic below would be incorrect"); | |
| 2816 MemRegion span = _gen->reserved(); | |
| 2817 if (low != NULL) { | |
| 2818 if (span.contains(low)) { | |
| 2819 // Align low down to a card boundary so that | |
| 2820 // we can use block_offset_careful() on span boundaries. | |
| 2821 HeapWord* aligned_low = (HeapWord*)align_size_down((uintptr_t)low, | |
| 2822 CardTableModRefBS::card_size); | |
| 2823 // Clip span prefix at aligned_low | |
| 2824 span = span.intersection(MemRegion(aligned_low, span.end())); | |
| 2825 } else if (low > span.end()) { | |
| 2826 span = MemRegion(low, low); // Null region | |
| 2827 } // else use entire span | |
| 2828 } | |
| 2829 assert(span.is_empty() || | |
| 2830 ((uintptr_t)span.start() % CardTableModRefBS::card_size == 0), | |
| 2831 "span should start at a card boundary"); | |
| 2832 size_t n_tasks = (span.word_size() + task_size - 1)/task_size; | |
| 2833 assert((n_tasks == 0) == span.is_empty(), "Inconsistency"); | |
| 2834 assert(n_tasks == 0 || | |
| 2835 ((span.start() + (n_tasks - 1)*task_size < span.end()) && | |
| 2836 (span.start() + n_tasks*task_size >= span.end())), | |
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2837 "n_tasks calculation incorrect"); |
| 0 | 2838 SequentialSubTasksDone* pst = conc_par_seq_tasks(); |
| 2839 assert(!pst->valid(), "Clobbering existing data?"); | |
| 2840 pst->set_par_threads(n_threads); | |
| 2841 pst->set_n_tasks((int)n_tasks); | |
| 2842 } |