Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp @ 14309:63a4eb8bcd23
8025856: Fix typos in the GC code
Summary: Fix about 440 typos in comments in the VM code
Reviewed-by: mgerdin, tschatzl, coleenp, kmo, jcoomes
| author | jwilhelm |
|---|---|
| date | Thu, 23 Jan 2014 14:47:23 +0100 |
| parents | de6a9e811145 |
| children | 4ca6dc0799b6 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP |
| 26 #define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP | |
| 27 | |
| 6885 | 28 #include "gc_implementation/concurrentMarkSweep/adaptiveFreeList.hpp" |
| 1972 | 29 #include "gc_implementation/concurrentMarkSweep/promotionInfo.hpp" |
| 6026 | 30 #include "memory/binaryTreeDictionary.hpp" |
| 1972 | 31 #include "memory/blockOffsetTable.inline.hpp" |
| 6026 | 32 #include "memory/freeList.hpp" |
| 1972 | 33 #include "memory/space.hpp" |
| 34 | |
| 0 | 35 // Classes in support of keeping track of promotions into a non-Contiguous |
| 36 // space, in this case a CompactibleFreeListSpace. | |
| 37 | |
| 38 // Forward declarations | |
| 39 class CompactibleFreeListSpace; | |
| 40 class BlkClosure; | |
| 41 class BlkClosureCareful; | |
| 6885 | 42 class FreeChunk; |
| 0 | 43 class UpwardsObjectClosure; |
| 44 class ObjectClosureCareful; | |
| 45 class Klass; | |
| 46 | |
| 47 class LinearAllocBlock VALUE_OBJ_CLASS_SPEC { | |
| 48 public: | |
| 49 LinearAllocBlock() : _ptr(0), _word_size(0), _refillSize(0), | |
| 50 _allocation_size_limit(0) {} | |
| 51 void set(HeapWord* ptr, size_t word_size, size_t refill_size, | |
| 52 size_t allocation_size_limit) { | |
| 53 _ptr = ptr; | |
| 54 _word_size = word_size; | |
| 55 _refillSize = refill_size; | |
| 56 _allocation_size_limit = allocation_size_limit; | |
| 57 } | |
| 58 HeapWord* _ptr; | |
| 59 size_t _word_size; | |
| 60 size_t _refillSize; | |
| 14309 | 61 size_t _allocation_size_limit; // Largest size that will be allocated |
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62 |
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63 void print_on(outputStream* st) const; |
| 0 | 64 }; |
| 65 | |
| 66 // Concrete subclass of CompactibleSpace that implements | |
| 67 // a free list space, such as used in the concurrent mark sweep | |
| 68 // generation. | |
| 69 | |
| 70 class CompactibleFreeListSpace: public CompactibleSpace { | |
| 71 friend class VMStructs; | |
| 72 friend class ConcurrentMarkSweepGeneration; | |
| 73 friend class ASConcurrentMarkSweepGeneration; | |
| 74 friend class CMSCollector; | |
| 75 // Local alloc buffer for promotion into this space. | |
| 76 friend class CFLS_LAB; | |
| 77 | |
| 78 // "Size" of chunks of work (executed during parallel remark phases | |
| 79 // of CMS collection); this probably belongs in CMSCollector, although | |
| 80 // it's cached here because it's used in | |
| 81 // initialize_sequential_subtasks_for_rescan() which modifies | |
| 82 // par_seq_tasks which also lives in Space. XXX | |
| 83 const size_t _rescan_task_size; | |
| 84 const size_t _marking_task_size; | |
| 85 | |
| 86 // Yet another sequential tasks done structure. This supports | |
| 87 // CMS GC, where we have threads dynamically | |
| 88 // claiming sub-tasks from a larger parallel task. | |
| 89 SequentialSubTasksDone _conc_par_seq_tasks; | |
| 90 | |
| 91 BlockOffsetArrayNonContigSpace _bt; | |
| 92 | |
| 93 CMSCollector* _collector; | |
| 94 ConcurrentMarkSweepGeneration* _gen; | |
| 95 | |
| 96 // Data structures for free blocks (used during allocation/sweeping) | |
| 97 | |
| 98 // Allocation is done linearly from two different blocks depending on | |
| 99 // whether the request is small or large, in an effort to reduce | |
| 100 // fragmentation. We assume that any locking for allocation is done | |
| 101 // by the containing generation. Thus, none of the methods in this | |
| 102 // space are re-entrant. | |
| 103 enum SomeConstants { | |
| 104 SmallForLinearAlloc = 16, // size < this then use _sLAB | |
| 105 SmallForDictionary = 257, // size < this then use _indexedFreeList | |
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106 IndexSetSize = SmallForDictionary // keep this odd-sized |
| 0 | 107 }; |
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108 static size_t IndexSetStart; |
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109 static size_t IndexSetStride; |
| 0 | 110 |
| 111 private: | |
| 112 enum FitStrategyOptions { | |
| 113 FreeBlockStrategyNone = 0, | |
| 114 FreeBlockBestFitFirst | |
| 115 }; | |
| 116 | |
| 117 PromotionInfo _promoInfo; | |
| 118 | |
| 14309 | 119 // Helps to impose a global total order on freelistLock ranks; |
| 0 | 120 // assumes that CFLSpace's are allocated in global total order |
| 121 static int _lockRank; | |
| 122 | |
| 14309 | 123 // A lock protecting the free lists and free blocks; |
| 0 | 124 // mutable because of ubiquity of locking even for otherwise const methods |
| 125 mutable Mutex _freelistLock; | |
| 14309 | 126 // Locking verifier convenience function |
| 0 | 127 void assert_locked() const PRODUCT_RETURN; |
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128 void assert_locked(const Mutex* lock) const PRODUCT_RETURN; |
| 0 | 129 |
| 130 // Linear allocation blocks | |
| 131 LinearAllocBlock _smallLinearAllocBlock; | |
| 132 | |
| 6026 | 133 FreeBlockDictionary<FreeChunk>::DictionaryChoice _dictionaryChoice; |
| 14309 | 134 AFLBinaryTreeDictionary* _dictionary; // Pointer to dictionary for large size blocks |
| 0 | 135 |
| 14309 | 136 // Indexed array for small size blocks |
| 6885 | 137 AdaptiveFreeList<FreeChunk> _indexedFreeList[IndexSetSize]; |
| 14309 | 138 |
| 139 // Allocation strategy | |
| 140 bool _fitStrategy; // Use best fit strategy | |
| 0 | 141 bool _adaptive_freelists; // Use adaptive freelists |
| 142 | |
| 143 // This is an address close to the largest free chunk in the heap. | |
| 144 // It is currently assumed to be at the end of the heap. Free | |
| 145 // chunks with addresses greater than nearLargestChunk are coalesced | |
| 146 // in an effort to maintain a large chunk at the end of the heap. | |
| 147 HeapWord* _nearLargestChunk; | |
| 148 | |
| 149 // Used to keep track of limit of sweep for the space | |
| 150 HeapWord* _sweep_limit; | |
| 151 | |
| 152 // Support for compacting cms | |
| 153 HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
| 154 HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); | |
| 155 | |
| 156 // Initialization helpers. | |
| 157 void initializeIndexedFreeListArray(); | |
| 158 | |
| 159 // Extra stuff to manage promotion parallelism. | |
| 160 | |
| 14309 | 161 // A lock protecting the dictionary during par promotion allocation. |
| 0 | 162 mutable Mutex _parDictionaryAllocLock; |
| 163 Mutex* parDictionaryAllocLock() const { return &_parDictionaryAllocLock; } | |
| 164 | |
| 165 // Locks protecting the exact lists during par promotion allocation. | |
| 166 Mutex* _indexedFreeListParLocks[IndexSetSize]; | |
| 167 | |
| 168 // Attempt to obtain up to "n" blocks of the size "word_sz" (which is | |
| 169 // required to be smaller than "IndexSetSize".) If successful, | |
| 170 // adds them to "fl", which is required to be an empty free list. | |
| 171 // If the count of "fl" is negative, it's absolute value indicates a | |
| 172 // number of free chunks that had been previously "borrowed" from global | |
| 173 // list of size "word_sz", and must now be decremented. | |
| 6885 | 174 void par_get_chunk_of_blocks(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl); |
| 0 | 175 |
| 176 // Allocation helper functions | |
| 177 // Allocate using a strategy that takes from the indexed free lists | |
| 178 // first. This allocation strategy assumes a companion sweeping | |
| 179 // strategy that attempts to keep the needed number of chunks in each | |
| 180 // indexed free lists. | |
| 181 HeapWord* allocate_adaptive_freelists(size_t size); | |
| 182 // Allocate from the linear allocation buffers first. This allocation | |
| 183 // strategy assumes maximal coalescing can maintain chunks large enough | |
| 184 // to be used as linear allocation buffers. | |
| 185 HeapWord* allocate_non_adaptive_freelists(size_t size); | |
| 186 | |
| 187 // Gets a chunk from the linear allocation block (LinAB). If there | |
| 188 // is not enough space in the LinAB, refills it. | |
| 189 HeapWord* getChunkFromLinearAllocBlock(LinearAllocBlock* blk, size_t size); | |
| 190 HeapWord* getChunkFromSmallLinearAllocBlock(size_t size); | |
| 191 // Get a chunk from the space remaining in the linear allocation block. Do | |
| 192 // not attempt to refill if the space is not available, return NULL. Do the | |
| 193 // repairs on the linear allocation block as appropriate. | |
| 194 HeapWord* getChunkFromLinearAllocBlockRemainder(LinearAllocBlock* blk, size_t size); | |
| 195 inline HeapWord* getChunkFromSmallLinearAllocBlockRemainder(size_t size); | |
| 196 | |
| 197 // Helper function for getChunkFromIndexedFreeList. | |
| 198 // Replenish the indexed free list for this "size". Do not take from an | |
| 199 // underpopulated size. | |
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200 FreeChunk* getChunkFromIndexedFreeListHelper(size_t size, bool replenish = true); |
| 0 | 201 |
| 202 // Get a chunk from the indexed free list. If the indexed free list | |
| 203 // does not have a free chunk, try to replenish the indexed free list | |
| 204 // then get the free chunk from the replenished indexed free list. | |
| 205 inline FreeChunk* getChunkFromIndexedFreeList(size_t size); | |
| 206 | |
| 207 // The returned chunk may be larger than requested (or null). | |
| 208 FreeChunk* getChunkFromDictionary(size_t size); | |
| 209 // The returned chunk is the exact size requested (or null). | |
| 210 FreeChunk* getChunkFromDictionaryExact(size_t size); | |
| 211 | |
| 212 // Find a chunk in the indexed free list that is the best | |
| 213 // fit for size "numWords". | |
| 214 FreeChunk* bestFitSmall(size_t numWords); | |
| 215 // For free list "fl" of chunks of size > numWords, | |
| 216 // remove a chunk, split off a chunk of size numWords | |
| 217 // and return it. The split off remainder is returned to | |
| 218 // the free lists. The old name for getFromListGreater | |
| 219 // was lookInListGreater. | |
| 6885 | 220 FreeChunk* getFromListGreater(AdaptiveFreeList<FreeChunk>* fl, size_t numWords); |
| 0 | 221 // Get a chunk in the indexed free list or dictionary, |
| 222 // by considering a larger chunk and splitting it. | |
| 223 FreeChunk* getChunkFromGreater(size_t numWords); | |
| 224 // Verify that the given chunk is in the indexed free lists. | |
| 225 bool verifyChunkInIndexedFreeLists(FreeChunk* fc) const; | |
| 226 // Remove the specified chunk from the indexed free lists. | |
| 227 void removeChunkFromIndexedFreeList(FreeChunk* fc); | |
| 228 // Remove the specified chunk from the dictionary. | |
| 229 void removeChunkFromDictionary(FreeChunk* fc); | |
| 230 // Split a free chunk into a smaller free chunk of size "new_size". | |
| 231 // Return the smaller free chunk and return the remainder to the | |
| 232 // free lists. | |
| 233 FreeChunk* splitChunkAndReturnRemainder(FreeChunk* chunk, size_t new_size); | |
| 234 // Add a chunk to the free lists. | |
| 235 void addChunkToFreeLists(HeapWord* chunk, size_t size); | |
| 236 // Add a chunk to the free lists, preferring to suffix it | |
| 237 // to the last free chunk at end of space if possible, and | |
| 238 // updating the block census stats as well as block offset table. | |
| 239 // Take any locks as appropriate if we are multithreaded. | |
| 240 void addChunkToFreeListsAtEndRecordingStats(HeapWord* chunk, size_t size); | |
| 241 // Add a free chunk to the indexed free lists. | |
| 242 void returnChunkToFreeList(FreeChunk* chunk); | |
| 243 // Add a free chunk to the dictionary. | |
| 244 void returnChunkToDictionary(FreeChunk* chunk); | |
| 245 | |
| 246 // Functions for maintaining the linear allocation buffers (LinAB). | |
| 247 // Repairing a linear allocation block refers to operations | |
| 248 // performed on the remainder of a LinAB after an allocation | |
| 249 // has been made from it. | |
| 250 void repairLinearAllocationBlocks(); | |
| 251 void repairLinearAllocBlock(LinearAllocBlock* blk); | |
| 252 void refillLinearAllocBlock(LinearAllocBlock* blk); | |
| 253 void refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk); | |
| 254 void refillLinearAllocBlocksIfNeeded(); | |
| 255 | |
| 256 void verify_objects_initialized() const; | |
| 257 | |
| 258 // Statistics reporting helper functions | |
| 259 void reportFreeListStatistics() const; | |
| 260 void reportIndexedFreeListStatistics() const; | |
| 261 size_t maxChunkSizeInIndexedFreeLists() const; | |
| 262 size_t numFreeBlocksInIndexedFreeLists() const; | |
| 263 // Accessor | |
| 264 HeapWord* unallocated_block() const { | |
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265 if (BlockOffsetArrayUseUnallocatedBlock) { |
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266 HeapWord* ub = _bt.unallocated_block(); |
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267 assert(ub >= bottom() && |
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268 ub <= end(), "space invariant"); |
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269 return ub; |
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270 } else { |
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271 return end(); |
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272 } |
| 0 | 273 } |
| 274 void freed(HeapWord* start, size_t size) { | |
| 275 _bt.freed(start, size); | |
| 276 } | |
| 277 | |
| 278 protected: | |
| 14309 | 279 // Reset the indexed free list to its initial empty condition. |
| 0 | 280 void resetIndexedFreeListArray(); |
| 14309 | 281 // Reset to an initial state with a single free block described |
| 0 | 282 // by the MemRegion parameter. |
| 283 void reset(MemRegion mr); | |
| 284 // Return the total number of words in the indexed free lists. | |
| 285 size_t totalSizeInIndexedFreeLists() const; | |
| 286 | |
| 287 public: | |
| 14309 | 288 // Constructor |
| 0 | 289 CompactibleFreeListSpace(BlockOffsetSharedArray* bs, MemRegion mr, |
| 290 bool use_adaptive_freelists, | |
| 6026 | 291 FreeBlockDictionary<FreeChunk>::DictionaryChoice); |
| 14309 | 292 // Accessors |
| 0 | 293 bool bestFitFirst() { return _fitStrategy == FreeBlockBestFitFirst; } |
| 6026 | 294 FreeBlockDictionary<FreeChunk>* dictionary() const { return _dictionary; } |
| 0 | 295 HeapWord* nearLargestChunk() const { return _nearLargestChunk; } |
| 296 void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; } | |
| 297 | |
| 14309 | 298 // Set CMS global values. |
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299 static void set_cms_values(); |
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300 |
| 0 | 301 // Return the free chunk at the end of the space. If no such |
| 302 // chunk exists, return NULL. | |
| 303 FreeChunk* find_chunk_at_end(); | |
| 304 | |
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305 bool adaptive_freelists() const { return _adaptive_freelists; } |
| 0 | 306 |
| 307 void set_collector(CMSCollector* collector) { _collector = collector; } | |
| 308 | |
| 14309 | 309 // Support for parallelization of rescan and marking. |
| 0 | 310 const size_t rescan_task_size() const { return _rescan_task_size; } |
| 311 const size_t marking_task_size() const { return _marking_task_size; } | |
| 312 SequentialSubTasksDone* conc_par_seq_tasks() {return &_conc_par_seq_tasks; } | |
| 313 void initialize_sequential_subtasks_for_rescan(int n_threads); | |
| 314 void initialize_sequential_subtasks_for_marking(int n_threads, | |
| 315 HeapWord* low = NULL); | |
| 316 | |
| 317 // Space enquiries | |
| 318 size_t used() const; | |
| 319 size_t free() const; | |
| 320 size_t max_alloc_in_words() const; | |
| 321 // XXX: should have a less conservative used_region() than that of | |
| 322 // Space; we could consider keeping track of highest allocated | |
| 323 // address and correcting that at each sweep, as the sweeper | |
| 324 // goes through the entire allocated part of the generation. We | |
| 325 // could also use that information to keep the sweeper from | |
| 326 // sweeping more than is necessary. The allocator and sweeper will | |
| 327 // of course need to synchronize on this, since the sweeper will | |
| 328 // try to bump down the address and the allocator will try to bump it up. | |
| 329 // For now, however, we'll just use the default used_region() | |
| 330 // which overestimates the region by returning the entire | |
| 331 // committed region (this is safe, but inefficient). | |
| 332 | |
| 333 // Returns a subregion of the space containing all the objects in | |
| 334 // the space. | |
| 335 MemRegion used_region() const { | |
| 336 return MemRegion(bottom(), | |
| 337 BlockOffsetArrayUseUnallocatedBlock ? | |
| 338 unallocated_block() : end()); | |
| 339 } | |
| 340 | |
| 341 bool is_in(const void* p) const { | |
| 342 return used_region().contains(p); | |
| 343 } | |
| 344 | |
| 345 virtual bool is_free_block(const HeapWord* p) const; | |
| 346 | |
| 347 // Resizing support | |
| 348 void set_end(HeapWord* value); // override | |
| 349 | |
| 14309 | 350 // Mutual exclusion support |
| 0 | 351 Mutex* freelistLock() const { return &_freelistLock; } |
| 352 | |
| 353 // Iteration support | |
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354 void oop_iterate(MemRegion mr, ExtendedOopClosure* cl); |
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355 void oop_iterate(ExtendedOopClosure* cl); |
| 0 | 356 |
| 357 void object_iterate(ObjectClosure* blk); | |
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358 // Apply the closure to each object in the space whose references |
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359 // point to objects in the heap. The usage of CompactibleFreeListSpace |
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360 // by the ConcurrentMarkSweepGeneration for concurrent GC's allows |
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361 // objects in the space with references to objects that are no longer |
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362 // valid. For example, an object may reference another object |
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363 // that has already been sweep up (collected). This method uses |
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364 // obj_is_alive() to determine whether it is safe to iterate of |
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365 // an object. |
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366 void safe_object_iterate(ObjectClosure* blk); |
| 0 | 367 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
| 368 | |
| 369 // Requires that "mr" be entirely within the space. | |
| 370 // Apply "cl->do_object" to all objects that intersect with "mr". | |
| 371 // If the iteration encounters an unparseable portion of the region, | |
| 372 // terminate the iteration and return the address of the start of the | |
| 373 // subregion that isn't done. Return of "NULL" indicates that the | |
| 14309 | 374 // iteration completed. |
| 0 | 375 virtual HeapWord* |
| 376 object_iterate_careful_m(MemRegion mr, | |
| 377 ObjectClosureCareful* cl); | |
| 378 virtual HeapWord* | |
| 379 object_iterate_careful(ObjectClosureCareful* cl); | |
| 380 | |
| 381 // Override: provides a DCTO_CL specific to this kind of space. | |
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382 DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl, |
| 0 | 383 CardTableModRefBS::PrecisionStyle precision, |
| 384 HeapWord* boundary); | |
| 385 | |
| 386 void blk_iterate(BlkClosure* cl); | |
| 387 void blk_iterate_careful(BlkClosureCareful* cl); | |
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388 HeapWord* block_start_const(const void* p) const; |
| 0 | 389 HeapWord* block_start_careful(const void* p) const; |
| 390 size_t block_size(const HeapWord* p) const; | |
| 391 size_t block_size_no_stall(HeapWord* p, const CMSCollector* c) const; | |
| 392 bool block_is_obj(const HeapWord* p) const; | |
| 393 bool obj_is_alive(const HeapWord* p) const; | |
| 394 size_t block_size_nopar(const HeapWord* p) const; | |
| 395 bool block_is_obj_nopar(const HeapWord* p) const; | |
| 396 | |
| 14309 | 397 // Iteration support for promotion |
| 0 | 398 void save_marks(); |
| 399 bool no_allocs_since_save_marks(); | |
| 400 | |
| 14309 | 401 // Iteration support for sweeping |
| 0 | 402 void save_sweep_limit() { |
| 403 _sweep_limit = BlockOffsetArrayUseUnallocatedBlock ? | |
| 404 unallocated_block() : end(); | |
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405 if (CMSTraceSweeper) { |
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406 gclog_or_tty->print_cr(">>>>> Saving sweep limit " PTR_FORMAT |
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407 " for space [" PTR_FORMAT "," PTR_FORMAT ") <<<<<<", |
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408 _sweep_limit, bottom(), end()); |
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409 } |
| 0 | 410 } |
| 411 NOT_PRODUCT( | |
| 412 void clear_sweep_limit() { _sweep_limit = NULL; } | |
| 413 ) | |
| 414 HeapWord* sweep_limit() { return _sweep_limit; } | |
| 415 | |
| 416 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
| 417 // promoted into this generation since the most recent save_marks() call. | |
| 418 // Fields in objects allocated by applications of the closure | |
| 419 // *are* included in the iteration. Thus, when the iteration completes | |
| 420 // there should be no further such objects remaining. | |
| 421 #define CFLS_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
| 422 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
| 423 ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DECL) | |
| 424 #undef CFLS_OOP_SINCE_SAVE_MARKS_DECL | |
| 425 | |
| 426 // Allocation support | |
| 427 HeapWord* allocate(size_t size); | |
| 428 HeapWord* par_allocate(size_t size); | |
| 429 | |
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430 oop promote(oop obj, size_t obj_size); |
| 0 | 431 void gc_prologue(); |
| 432 void gc_epilogue(); | |
| 433 | |
| 434 // This call is used by a containing CMS generation / collector | |
| 435 // to inform the CFLS space that a sweep has been completed | |
| 436 // and that the space can do any related house-keeping functions. | |
| 437 void sweep_completed(); | |
| 438 | |
| 439 // For an object in this space, the mark-word's two | |
| 440 // LSB's having the value [11] indicates that it has been | |
| 441 // promoted since the most recent call to save_marks() on | |
| 442 // this generation and has not subsequently been iterated | |
| 443 // over (using oop_since_save_marks_iterate() above). | |
| 1521 | 444 // This property holds only for single-threaded collections, |
| 445 // and is typically used for Cheney scans; for MT scavenges, | |
| 446 // the property holds for all objects promoted during that | |
| 447 // scavenge for the duration of the scavenge and is used | |
| 448 // by card-scanning to avoid scanning objects (being) promoted | |
| 449 // during that scavenge. | |
| 0 | 450 bool obj_allocated_since_save_marks(const oop obj) const { |
| 451 assert(is_in_reserved(obj), "Wrong space?"); | |
| 452 return ((PromotedObject*)obj)->hasPromotedMark(); | |
| 453 } | |
| 454 | |
| 455 // A worst-case estimate of the space required (in HeapWords) to expand the | |
| 456 // heap when promoting an obj of size obj_size. | |
| 457 size_t expansionSpaceRequired(size_t obj_size) const; | |
| 458 | |
| 459 FreeChunk* allocateScratch(size_t size); | |
| 460 | |
| 14309 | 461 // Returns true if either the small or large linear allocation buffer is empty. |
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462 bool linearAllocationWouldFail() const; |
| 0 | 463 |
| 464 // Adjust the chunk for the minimum size. This version is called in | |
| 465 // most cases in CompactibleFreeListSpace methods. | |
| 466 inline static size_t adjustObjectSize(size_t size) { | |
| 467 return (size_t) align_object_size(MAX2(size, (size_t)MinChunkSize)); | |
| 468 } | |
| 469 // This is a virtual version of adjustObjectSize() that is called | |
| 470 // only occasionally when the compaction space changes and the type | |
| 471 // of the new compaction space is is only known to be CompactibleSpace. | |
| 472 size_t adjust_object_size_v(size_t size) const { | |
| 473 return adjustObjectSize(size); | |
| 474 } | |
| 475 // Minimum size of a free block. | |
| 476 virtual size_t minimum_free_block_size() const { return MinChunkSize; } | |
| 477 void removeFreeChunkFromFreeLists(FreeChunk* chunk); | |
| 478 void addChunkAndRepairOffsetTable(HeapWord* chunk, size_t size, | |
| 479 bool coalesced); | |
| 480 | |
| 14309 | 481 // Support for decisions regarding concurrent collection policy. |
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482 bool should_concurrent_collect() const; |
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483 |
| 14309 | 484 // Support for compaction. |
| 0 | 485 void prepare_for_compaction(CompactPoint* cp); |
| 486 void adjust_pointers(); | |
| 487 void compact(); | |
| 14309 | 488 // Reset the space to reflect the fact that a compaction of the |
| 0 | 489 // space has been done. |
| 490 virtual void reset_after_compaction(); | |
| 491 | |
| 14309 | 492 // Debugging support. |
| 0 | 493 void print() const; |
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494 void print_on(outputStream* st) const; |
| 0 | 495 void prepare_for_verify(); |
| 6008 | 496 void verify() const; |
| 0 | 497 void verifyFreeLists() const PRODUCT_RETURN; |
| 498 void verifyIndexedFreeLists() const; | |
| 499 void verifyIndexedFreeList(size_t size) const; | |
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500 // Verify that the given chunk is in the free lists: |
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501 // i.e. either the binary tree dictionary, the indexed free lists |
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502 // or the linear allocation block. |
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503 bool verify_chunk_in_free_list(FreeChunk* fc) const; |
| 14309 | 504 // Verify that the given chunk is the linear allocation block. |
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505 bool verify_chunk_is_linear_alloc_block(FreeChunk* fc) const; |
| 0 | 506 // Do some basic checks on the the free lists. |
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507 void check_free_list_consistency() const PRODUCT_RETURN; |
| 0 | 508 |
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509 // Printing support |
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510 void dump_at_safepoint_with_locks(CMSCollector* c, outputStream* st); |
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511 void print_indexed_free_lists(outputStream* st) const; |
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512 void print_dictionary_free_lists(outputStream* st) const; |
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513 void print_promo_info_blocks(outputStream* st) const; |
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514 |
| 0 | 515 NOT_PRODUCT ( |
| 516 void initializeIndexedFreeListArrayReturnedBytes(); | |
| 517 size_t sumIndexedFreeListArrayReturnedBytes(); | |
| 518 // Return the total number of chunks in the indexed free lists. | |
| 519 size_t totalCountInIndexedFreeLists() const; | |
| 14309 | 520 // Return the total number of chunks in the space. |
| 0 | 521 size_t totalCount(); |
| 522 ) | |
| 523 | |
| 524 // The census consists of counts of the quantities such as | |
| 525 // the current count of the free chunks, number of chunks | |
| 526 // created as a result of the split of a larger chunk or | |
| 527 // coalescing of smaller chucks, etc. The counts in the | |
| 528 // census is used to make decisions on splitting and | |
| 529 // coalescing of chunks during the sweep of garbage. | |
| 530 | |
| 531 // Print the statistics for the free lists. | |
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532 void printFLCensus(size_t sweep_count) const; |
| 0 | 533 |
| 534 // Statistics functions | |
| 535 // Initialize census for lists before the sweep. | |
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536 void beginSweepFLCensus(float inter_sweep_current, |
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537 float inter_sweep_estimate, |
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538 float intra_sweep_estimate); |
| 0 | 539 // Set the surplus for each of the free lists. |
| 540 void setFLSurplus(); | |
| 541 // Set the hint for each of the free lists. | |
| 542 void setFLHints(); | |
| 543 // Clear the census for each of the free lists. | |
| 544 void clearFLCensus(); | |
| 545 // Perform functions for the census after the end of the sweep. | |
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546 void endSweepFLCensus(size_t sweep_count); |
| 0 | 547 // Return true if the count of free chunks is greater |
| 548 // than the desired number of free chunks. | |
| 549 bool coalOverPopulated(size_t size); | |
| 550 | |
| 551 // Record (for each size): | |
| 552 // | |
| 553 // split-births = #chunks added due to splits in (prev-sweep-end, | |
| 554 // this-sweep-start) | |
| 555 // split-deaths = #chunks removed for splits in (prev-sweep-end, | |
| 556 // this-sweep-start) | |
| 557 // num-curr = #chunks at start of this sweep | |
| 558 // num-prev = #chunks at end of previous sweep | |
| 559 // | |
| 560 // The above are quantities that are measured. Now define: | |
| 561 // | |
| 562 // num-desired := num-prev + split-births - split-deaths - num-curr | |
| 563 // | |
| 564 // Roughly, num-prev + split-births is the supply, | |
| 565 // split-deaths is demand due to other sizes | |
| 566 // and num-curr is what we have left. | |
| 567 // | |
| 568 // Thus, num-desired is roughly speaking the "legitimate demand" | |
| 569 // for blocks of this size and what we are striving to reach at the | |
| 570 // end of the current sweep. | |
| 571 // | |
| 572 // For a given list, let num-len be its current population. | |
| 573 // Define, for a free list of a given size: | |
| 574 // | |
| 575 // coal-overpopulated := num-len >= num-desired * coal-surplus | |
| 576 // (coal-surplus is set to 1.05, i.e. we allow a little slop when | |
| 577 // coalescing -- we do not coalesce unless we think that the current | |
| 578 // supply has exceeded the estimated demand by more than 5%). | |
| 579 // | |
| 580 // For the set of sizes in the binary tree, which is neither dense nor | |
| 581 // closed, it may be the case that for a particular size we have never | |
| 582 // had, or do not now have, or did not have at the previous sweep, | |
| 583 // chunks of that size. We need to extend the definition of | |
| 584 // coal-overpopulated to such sizes as well: | |
| 585 // | |
| 586 // For a chunk in/not in the binary tree, extend coal-overpopulated | |
| 587 // defined above to include all sizes as follows: | |
| 588 // | |
| 589 // . a size that is non-existent is coal-overpopulated | |
| 590 // . a size that has a num-desired <= 0 as defined above is | |
| 591 // coal-overpopulated. | |
| 592 // | |
| 593 // Also define, for a chunk heap-offset C and mountain heap-offset M: | |
| 594 // | |
| 595 // close-to-mountain := C >= 0.99 * M | |
| 596 // | |
| 597 // Now, the coalescing strategy is: | |
| 598 // | |
| 599 // Coalesce left-hand chunk with right-hand chunk if and | |
| 600 // only if: | |
| 601 // | |
| 602 // EITHER | |
| 603 // . left-hand chunk is of a size that is coal-overpopulated | |
| 604 // OR | |
| 605 // . right-hand chunk is close-to-mountain | |
| 606 void smallCoalBirth(size_t size); | |
| 607 void smallCoalDeath(size_t size); | |
| 608 void coalBirth(size_t size); | |
| 609 void coalDeath(size_t size); | |
| 610 void smallSplitBirth(size_t size); | |
| 611 void smallSplitDeath(size_t size); | |
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612 void split_birth(size_t size); |
| 0 | 613 void splitDeath(size_t size); |
| 614 void split(size_t from, size_t to1); | |
| 615 | |
| 616 double flsFrag() const; | |
| 617 }; | |
| 618 | |
| 619 // A parallel-GC-thread-local allocation buffer for allocation into a | |
| 620 // CompactibleFreeListSpace. | |
| 6197 | 621 class CFLS_LAB : public CHeapObj<mtGC> { |
| 0 | 622 // The space that this buffer allocates into. |
| 623 CompactibleFreeListSpace* _cfls; | |
| 624 | |
| 625 // Our local free lists. | |
| 6885 | 626 AdaptiveFreeList<FreeChunk> _indexedFreeList[CompactibleFreeListSpace::IndexSetSize]; |
| 0 | 627 |
| 628 // Initialized from a command-line arg. | |
| 629 | |
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630 // Allocation statistics in support of dynamic adjustment of |
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631 // #blocks to claim per get_from_global_pool() call below. |
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632 static AdaptiveWeightedAverage |
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633 _blocks_to_claim [CompactibleFreeListSpace::IndexSetSize]; |
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634 static size_t _global_num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
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635 static uint _global_num_workers[CompactibleFreeListSpace::IndexSetSize]; |
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636 size_t _num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
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637 |
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638 // Internal work method |
| 6885 | 639 void get_from_global_pool(size_t word_sz, AdaptiveFreeList<FreeChunk>* fl); |
| 0 | 640 |
| 641 public: | |
| 642 CFLS_LAB(CompactibleFreeListSpace* cfls); | |
| 643 | |
| 644 // Allocate and return a block of the given size, or else return NULL. | |
| 645 HeapWord* alloc(size_t word_sz); | |
| 646 | |
| 647 // Return any unused portions of the buffer to the global pool. | |
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648 void retire(int tid); |
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649 |
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650 // Dynamic OldPLABSize sizing |
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651 static void compute_desired_plab_size(); |
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652 // When the settings are modified from default static initialization |
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653 static void modify_initialization(size_t n, unsigned wt); |
| 0 | 654 }; |
| 655 | |
| 656 size_t PromotionInfo::refillSize() const { | |
| 657 const size_t CMSSpoolBlockSize = 256; | |
| 658 const size_t sz = heap_word_size(sizeof(SpoolBlock) + sizeof(markOop) | |
| 659 * CMSSpoolBlockSize); | |
| 660 return CompactibleFreeListSpace::adjustObjectSize(sz); | |
| 661 } | |
| 1972 | 662 |
| 663 #endif // SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP |