Thu, 27 May 2010 18:01:56 -0700
6916623: Align object to 16 bytes to use Compressed Oops with java heap up to 64Gb
Summary: Added new product ObjectAlignmentInBytes flag to control object alignment.
Reviewed-by: twisti, ysr, iveresov
duke@435 | 1 | /* |
xdono@1014 | 2 | * Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | // Classes in support of keeping track of promotions into a non-Contiguous |
duke@435 | 26 | // space, in this case a CompactibleFreeListSpace. |
duke@435 | 27 | |
duke@435 | 28 | // Forward declarations |
duke@435 | 29 | class CompactibleFreeListSpace; |
duke@435 | 30 | class BlkClosure; |
duke@435 | 31 | class BlkClosureCareful; |
duke@435 | 32 | class UpwardsObjectClosure; |
duke@435 | 33 | class ObjectClosureCareful; |
duke@435 | 34 | class Klass; |
duke@435 | 35 | |
duke@435 | 36 | class LinearAllocBlock VALUE_OBJ_CLASS_SPEC { |
duke@435 | 37 | public: |
duke@435 | 38 | LinearAllocBlock() : _ptr(0), _word_size(0), _refillSize(0), |
duke@435 | 39 | _allocation_size_limit(0) {} |
duke@435 | 40 | void set(HeapWord* ptr, size_t word_size, size_t refill_size, |
duke@435 | 41 | size_t allocation_size_limit) { |
duke@435 | 42 | _ptr = ptr; |
duke@435 | 43 | _word_size = word_size; |
duke@435 | 44 | _refillSize = refill_size; |
duke@435 | 45 | _allocation_size_limit = allocation_size_limit; |
duke@435 | 46 | } |
duke@435 | 47 | HeapWord* _ptr; |
duke@435 | 48 | size_t _word_size; |
duke@435 | 49 | size_t _refillSize; |
duke@435 | 50 | size_t _allocation_size_limit; // largest size that will be allocated |
duke@435 | 51 | }; |
duke@435 | 52 | |
duke@435 | 53 | // Concrete subclass of CompactibleSpace that implements |
duke@435 | 54 | // a free list space, such as used in the concurrent mark sweep |
duke@435 | 55 | // generation. |
duke@435 | 56 | |
duke@435 | 57 | class CompactibleFreeListSpace: public CompactibleSpace { |
duke@435 | 58 | friend class VMStructs; |
duke@435 | 59 | friend class ConcurrentMarkSweepGeneration; |
duke@435 | 60 | friend class ASConcurrentMarkSweepGeneration; |
duke@435 | 61 | friend class CMSCollector; |
duke@435 | 62 | friend class CMSPermGenGen; |
duke@435 | 63 | // Local alloc buffer for promotion into this space. |
duke@435 | 64 | friend class CFLS_LAB; |
duke@435 | 65 | |
duke@435 | 66 | // "Size" of chunks of work (executed during parallel remark phases |
duke@435 | 67 | // of CMS collection); this probably belongs in CMSCollector, although |
duke@435 | 68 | // it's cached here because it's used in |
duke@435 | 69 | // initialize_sequential_subtasks_for_rescan() which modifies |
duke@435 | 70 | // par_seq_tasks which also lives in Space. XXX |
duke@435 | 71 | const size_t _rescan_task_size; |
duke@435 | 72 | const size_t _marking_task_size; |
duke@435 | 73 | |
duke@435 | 74 | // Yet another sequential tasks done structure. This supports |
duke@435 | 75 | // CMS GC, where we have threads dynamically |
duke@435 | 76 | // claiming sub-tasks from a larger parallel task. |
duke@435 | 77 | SequentialSubTasksDone _conc_par_seq_tasks; |
duke@435 | 78 | |
duke@435 | 79 | BlockOffsetArrayNonContigSpace _bt; |
duke@435 | 80 | |
duke@435 | 81 | CMSCollector* _collector; |
duke@435 | 82 | ConcurrentMarkSweepGeneration* _gen; |
duke@435 | 83 | |
duke@435 | 84 | // Data structures for free blocks (used during allocation/sweeping) |
duke@435 | 85 | |
duke@435 | 86 | // Allocation is done linearly from two different blocks depending on |
duke@435 | 87 | // whether the request is small or large, in an effort to reduce |
duke@435 | 88 | // fragmentation. We assume that any locking for allocation is done |
duke@435 | 89 | // by the containing generation. Thus, none of the methods in this |
duke@435 | 90 | // space are re-entrant. |
duke@435 | 91 | enum SomeConstants { |
duke@435 | 92 | SmallForLinearAlloc = 16, // size < this then use _sLAB |
duke@435 | 93 | SmallForDictionary = 257, // size < this then use _indexedFreeList |
kvn@1926 | 94 | IndexSetSize = SmallForDictionary // keep this odd-sized |
duke@435 | 95 | }; |
kvn@1926 | 96 | static int IndexSetStart; |
kvn@1926 | 97 | static int IndexSetStride; |
duke@435 | 98 | |
duke@435 | 99 | private: |
duke@435 | 100 | enum FitStrategyOptions { |
duke@435 | 101 | FreeBlockStrategyNone = 0, |
duke@435 | 102 | FreeBlockBestFitFirst |
duke@435 | 103 | }; |
duke@435 | 104 | |
duke@435 | 105 | PromotionInfo _promoInfo; |
duke@435 | 106 | |
duke@435 | 107 | // helps to impose a global total order on freelistLock ranks; |
duke@435 | 108 | // assumes that CFLSpace's are allocated in global total order |
duke@435 | 109 | static int _lockRank; |
duke@435 | 110 | |
duke@435 | 111 | // a lock protecting the free lists and free blocks; |
duke@435 | 112 | // mutable because of ubiquity of locking even for otherwise const methods |
duke@435 | 113 | mutable Mutex _freelistLock; |
duke@435 | 114 | // locking verifier convenience function |
duke@435 | 115 | void assert_locked() const PRODUCT_RETURN; |
ysr@1580 | 116 | void assert_locked(const Mutex* lock) const PRODUCT_RETURN; |
duke@435 | 117 | |
duke@435 | 118 | // Linear allocation blocks |
duke@435 | 119 | LinearAllocBlock _smallLinearAllocBlock; |
duke@435 | 120 | |
duke@435 | 121 | FreeBlockDictionary::DictionaryChoice _dictionaryChoice; |
duke@435 | 122 | FreeBlockDictionary* _dictionary; // ptr to dictionary for large size blocks |
duke@435 | 123 | |
duke@435 | 124 | FreeList _indexedFreeList[IndexSetSize]; |
duke@435 | 125 | // indexed array for small size blocks |
duke@435 | 126 | // allocation stategy |
duke@435 | 127 | bool _fitStrategy; // Use best fit strategy. |
duke@435 | 128 | bool _adaptive_freelists; // Use adaptive freelists |
duke@435 | 129 | |
duke@435 | 130 | // This is an address close to the largest free chunk in the heap. |
duke@435 | 131 | // It is currently assumed to be at the end of the heap. Free |
duke@435 | 132 | // chunks with addresses greater than nearLargestChunk are coalesced |
duke@435 | 133 | // in an effort to maintain a large chunk at the end of the heap. |
duke@435 | 134 | HeapWord* _nearLargestChunk; |
duke@435 | 135 | |
duke@435 | 136 | // Used to keep track of limit of sweep for the space |
duke@435 | 137 | HeapWord* _sweep_limit; |
duke@435 | 138 | |
duke@435 | 139 | // Support for compacting cms |
duke@435 | 140 | HeapWord* cross_threshold(HeapWord* start, HeapWord* end); |
duke@435 | 141 | HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); |
duke@435 | 142 | |
duke@435 | 143 | // Initialization helpers. |
duke@435 | 144 | void initializeIndexedFreeListArray(); |
duke@435 | 145 | |
duke@435 | 146 | // Extra stuff to manage promotion parallelism. |
duke@435 | 147 | |
duke@435 | 148 | // a lock protecting the dictionary during par promotion allocation. |
duke@435 | 149 | mutable Mutex _parDictionaryAllocLock; |
duke@435 | 150 | Mutex* parDictionaryAllocLock() const { return &_parDictionaryAllocLock; } |
duke@435 | 151 | |
duke@435 | 152 | // Locks protecting the exact lists during par promotion allocation. |
duke@435 | 153 | Mutex* _indexedFreeListParLocks[IndexSetSize]; |
duke@435 | 154 | |
duke@435 | 155 | // Attempt to obtain up to "n" blocks of the size "word_sz" (which is |
duke@435 | 156 | // required to be smaller than "IndexSetSize".) If successful, |
duke@435 | 157 | // adds them to "fl", which is required to be an empty free list. |
duke@435 | 158 | // If the count of "fl" is negative, it's absolute value indicates a |
duke@435 | 159 | // number of free chunks that had been previously "borrowed" from global |
duke@435 | 160 | // list of size "word_sz", and must now be decremented. |
duke@435 | 161 | void par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl); |
duke@435 | 162 | |
duke@435 | 163 | // Allocation helper functions |
duke@435 | 164 | // Allocate using a strategy that takes from the indexed free lists |
duke@435 | 165 | // first. This allocation strategy assumes a companion sweeping |
duke@435 | 166 | // strategy that attempts to keep the needed number of chunks in each |
duke@435 | 167 | // indexed free lists. |
duke@435 | 168 | HeapWord* allocate_adaptive_freelists(size_t size); |
duke@435 | 169 | // Allocate from the linear allocation buffers first. This allocation |
duke@435 | 170 | // strategy assumes maximal coalescing can maintain chunks large enough |
duke@435 | 171 | // to be used as linear allocation buffers. |
duke@435 | 172 | HeapWord* allocate_non_adaptive_freelists(size_t size); |
duke@435 | 173 | |
duke@435 | 174 | // Gets a chunk from the linear allocation block (LinAB). If there |
duke@435 | 175 | // is not enough space in the LinAB, refills it. |
duke@435 | 176 | HeapWord* getChunkFromLinearAllocBlock(LinearAllocBlock* blk, size_t size); |
duke@435 | 177 | HeapWord* getChunkFromSmallLinearAllocBlock(size_t size); |
duke@435 | 178 | // Get a chunk from the space remaining in the linear allocation block. Do |
duke@435 | 179 | // not attempt to refill if the space is not available, return NULL. Do the |
duke@435 | 180 | // repairs on the linear allocation block as appropriate. |
duke@435 | 181 | HeapWord* getChunkFromLinearAllocBlockRemainder(LinearAllocBlock* blk, size_t size); |
duke@435 | 182 | inline HeapWord* getChunkFromSmallLinearAllocBlockRemainder(size_t size); |
duke@435 | 183 | |
duke@435 | 184 | // Helper function for getChunkFromIndexedFreeList. |
duke@435 | 185 | // Replenish the indexed free list for this "size". Do not take from an |
duke@435 | 186 | // underpopulated size. |
ysr@1580 | 187 | FreeChunk* getChunkFromIndexedFreeListHelper(size_t size, bool replenish = true); |
duke@435 | 188 | |
duke@435 | 189 | // Get a chunk from the indexed free list. If the indexed free list |
duke@435 | 190 | // does not have a free chunk, try to replenish the indexed free list |
duke@435 | 191 | // then get the free chunk from the replenished indexed free list. |
duke@435 | 192 | inline FreeChunk* getChunkFromIndexedFreeList(size_t size); |
duke@435 | 193 | |
duke@435 | 194 | // The returned chunk may be larger than requested (or null). |
duke@435 | 195 | FreeChunk* getChunkFromDictionary(size_t size); |
duke@435 | 196 | // The returned chunk is the exact size requested (or null). |
duke@435 | 197 | FreeChunk* getChunkFromDictionaryExact(size_t size); |
duke@435 | 198 | |
duke@435 | 199 | // Find a chunk in the indexed free list that is the best |
duke@435 | 200 | // fit for size "numWords". |
duke@435 | 201 | FreeChunk* bestFitSmall(size_t numWords); |
duke@435 | 202 | // For free list "fl" of chunks of size > numWords, |
duke@435 | 203 | // remove a chunk, split off a chunk of size numWords |
duke@435 | 204 | // and return it. The split off remainder is returned to |
duke@435 | 205 | // the free lists. The old name for getFromListGreater |
duke@435 | 206 | // was lookInListGreater. |
duke@435 | 207 | FreeChunk* getFromListGreater(FreeList* fl, size_t numWords); |
duke@435 | 208 | // Get a chunk in the indexed free list or dictionary, |
duke@435 | 209 | // by considering a larger chunk and splitting it. |
duke@435 | 210 | FreeChunk* getChunkFromGreater(size_t numWords); |
duke@435 | 211 | // Verify that the given chunk is in the indexed free lists. |
duke@435 | 212 | bool verifyChunkInIndexedFreeLists(FreeChunk* fc) const; |
duke@435 | 213 | // Remove the specified chunk from the indexed free lists. |
duke@435 | 214 | void removeChunkFromIndexedFreeList(FreeChunk* fc); |
duke@435 | 215 | // Remove the specified chunk from the dictionary. |
duke@435 | 216 | void removeChunkFromDictionary(FreeChunk* fc); |
duke@435 | 217 | // Split a free chunk into a smaller free chunk of size "new_size". |
duke@435 | 218 | // Return the smaller free chunk and return the remainder to the |
duke@435 | 219 | // free lists. |
duke@435 | 220 | FreeChunk* splitChunkAndReturnRemainder(FreeChunk* chunk, size_t new_size); |
duke@435 | 221 | // Add a chunk to the free lists. |
duke@435 | 222 | void addChunkToFreeLists(HeapWord* chunk, size_t size); |
duke@435 | 223 | // Add a chunk to the free lists, preferring to suffix it |
duke@435 | 224 | // to the last free chunk at end of space if possible, and |
duke@435 | 225 | // updating the block census stats as well as block offset table. |
duke@435 | 226 | // Take any locks as appropriate if we are multithreaded. |
duke@435 | 227 | void addChunkToFreeListsAtEndRecordingStats(HeapWord* chunk, size_t size); |
duke@435 | 228 | // Add a free chunk to the indexed free lists. |
duke@435 | 229 | void returnChunkToFreeList(FreeChunk* chunk); |
duke@435 | 230 | // Add a free chunk to the dictionary. |
duke@435 | 231 | void returnChunkToDictionary(FreeChunk* chunk); |
duke@435 | 232 | |
duke@435 | 233 | // Functions for maintaining the linear allocation buffers (LinAB). |
duke@435 | 234 | // Repairing a linear allocation block refers to operations |
duke@435 | 235 | // performed on the remainder of a LinAB after an allocation |
duke@435 | 236 | // has been made from it. |
duke@435 | 237 | void repairLinearAllocationBlocks(); |
duke@435 | 238 | void repairLinearAllocBlock(LinearAllocBlock* blk); |
duke@435 | 239 | void refillLinearAllocBlock(LinearAllocBlock* blk); |
duke@435 | 240 | void refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk); |
duke@435 | 241 | void refillLinearAllocBlocksIfNeeded(); |
duke@435 | 242 | |
duke@435 | 243 | void verify_objects_initialized() const; |
duke@435 | 244 | |
duke@435 | 245 | // Statistics reporting helper functions |
duke@435 | 246 | void reportFreeListStatistics() const; |
duke@435 | 247 | void reportIndexedFreeListStatistics() const; |
duke@435 | 248 | size_t maxChunkSizeInIndexedFreeLists() const; |
duke@435 | 249 | size_t numFreeBlocksInIndexedFreeLists() const; |
duke@435 | 250 | // Accessor |
duke@435 | 251 | HeapWord* unallocated_block() const { |
duke@435 | 252 | HeapWord* ub = _bt.unallocated_block(); |
duke@435 | 253 | assert(ub >= bottom() && |
duke@435 | 254 | ub <= end(), "space invariant"); |
duke@435 | 255 | return ub; |
duke@435 | 256 | } |
duke@435 | 257 | void freed(HeapWord* start, size_t size) { |
duke@435 | 258 | _bt.freed(start, size); |
duke@435 | 259 | } |
duke@435 | 260 | |
duke@435 | 261 | protected: |
duke@435 | 262 | // reset the indexed free list to its initial empty condition. |
duke@435 | 263 | void resetIndexedFreeListArray(); |
duke@435 | 264 | // reset to an initial state with a single free block described |
duke@435 | 265 | // by the MemRegion parameter. |
duke@435 | 266 | void reset(MemRegion mr); |
duke@435 | 267 | // Return the total number of words in the indexed free lists. |
duke@435 | 268 | size_t totalSizeInIndexedFreeLists() const; |
duke@435 | 269 | |
duke@435 | 270 | public: |
duke@435 | 271 | // Constructor... |
duke@435 | 272 | CompactibleFreeListSpace(BlockOffsetSharedArray* bs, MemRegion mr, |
duke@435 | 273 | bool use_adaptive_freelists, |
duke@435 | 274 | FreeBlockDictionary::DictionaryChoice); |
duke@435 | 275 | // accessors |
duke@435 | 276 | bool bestFitFirst() { return _fitStrategy == FreeBlockBestFitFirst; } |
duke@435 | 277 | FreeBlockDictionary* dictionary() const { return _dictionary; } |
duke@435 | 278 | HeapWord* nearLargestChunk() const { return _nearLargestChunk; } |
duke@435 | 279 | void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; } |
duke@435 | 280 | |
kvn@1926 | 281 | // Set CMS global values |
kvn@1926 | 282 | static void set_cms_values(); |
kvn@1926 | 283 | |
duke@435 | 284 | // Return the free chunk at the end of the space. If no such |
duke@435 | 285 | // chunk exists, return NULL. |
duke@435 | 286 | FreeChunk* find_chunk_at_end(); |
duke@435 | 287 | |
ysr@447 | 288 | bool adaptive_freelists() const { return _adaptive_freelists; } |
duke@435 | 289 | |
duke@435 | 290 | void set_collector(CMSCollector* collector) { _collector = collector; } |
duke@435 | 291 | |
duke@435 | 292 | // Support for parallelization of rescan and marking |
duke@435 | 293 | const size_t rescan_task_size() const { return _rescan_task_size; } |
duke@435 | 294 | const size_t marking_task_size() const { return _marking_task_size; } |
duke@435 | 295 | SequentialSubTasksDone* conc_par_seq_tasks() {return &_conc_par_seq_tasks; } |
duke@435 | 296 | void initialize_sequential_subtasks_for_rescan(int n_threads); |
duke@435 | 297 | void initialize_sequential_subtasks_for_marking(int n_threads, |
duke@435 | 298 | HeapWord* low = NULL); |
duke@435 | 299 | |
duke@435 | 300 | // Space enquiries |
duke@435 | 301 | size_t used() const; |
duke@435 | 302 | size_t free() const; |
duke@435 | 303 | size_t max_alloc_in_words() const; |
duke@435 | 304 | // XXX: should have a less conservative used_region() than that of |
duke@435 | 305 | // Space; we could consider keeping track of highest allocated |
duke@435 | 306 | // address and correcting that at each sweep, as the sweeper |
duke@435 | 307 | // goes through the entire allocated part of the generation. We |
duke@435 | 308 | // could also use that information to keep the sweeper from |
duke@435 | 309 | // sweeping more than is necessary. The allocator and sweeper will |
duke@435 | 310 | // of course need to synchronize on this, since the sweeper will |
duke@435 | 311 | // try to bump down the address and the allocator will try to bump it up. |
duke@435 | 312 | // For now, however, we'll just use the default used_region() |
duke@435 | 313 | // which overestimates the region by returning the entire |
duke@435 | 314 | // committed region (this is safe, but inefficient). |
duke@435 | 315 | |
duke@435 | 316 | // Returns a subregion of the space containing all the objects in |
duke@435 | 317 | // the space. |
duke@435 | 318 | MemRegion used_region() const { |
duke@435 | 319 | return MemRegion(bottom(), |
duke@435 | 320 | BlockOffsetArrayUseUnallocatedBlock ? |
duke@435 | 321 | unallocated_block() : end()); |
duke@435 | 322 | } |
duke@435 | 323 | |
duke@435 | 324 | // This is needed because the default implementation uses block_start() |
duke@435 | 325 | // which can;t be used at certain times (for example phase 3 of mark-sweep). |
duke@435 | 326 | // A better fix is to change the assertions in phase 3 of mark-sweep to |
duke@435 | 327 | // use is_in_reserved(), but that is deferred since the is_in() assertions |
duke@435 | 328 | // are buried through several layers of callers and are used elsewhere |
duke@435 | 329 | // as well. |
duke@435 | 330 | bool is_in(const void* p) const { |
duke@435 | 331 | return used_region().contains(p); |
duke@435 | 332 | } |
duke@435 | 333 | |
duke@435 | 334 | virtual bool is_free_block(const HeapWord* p) const; |
duke@435 | 335 | |
duke@435 | 336 | // Resizing support |
duke@435 | 337 | void set_end(HeapWord* value); // override |
duke@435 | 338 | |
duke@435 | 339 | // mutual exclusion support |
duke@435 | 340 | Mutex* freelistLock() const { return &_freelistLock; } |
duke@435 | 341 | |
duke@435 | 342 | // Iteration support |
duke@435 | 343 | void oop_iterate(MemRegion mr, OopClosure* cl); |
duke@435 | 344 | void oop_iterate(OopClosure* cl); |
duke@435 | 345 | |
duke@435 | 346 | void object_iterate(ObjectClosure* blk); |
jmasa@952 | 347 | // Apply the closure to each object in the space whose references |
jmasa@952 | 348 | // point to objects in the heap. The usage of CompactibleFreeListSpace |
jmasa@952 | 349 | // by the ConcurrentMarkSweepGeneration for concurrent GC's allows |
jmasa@952 | 350 | // objects in the space with references to objects that are no longer |
jmasa@952 | 351 | // valid. For example, an object may reference another object |
jmasa@952 | 352 | // that has already been sweep up (collected). This method uses |
jmasa@952 | 353 | // obj_is_alive() to determine whether it is safe to iterate of |
jmasa@952 | 354 | // an object. |
jmasa@952 | 355 | void safe_object_iterate(ObjectClosure* blk); |
duke@435 | 356 | void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
duke@435 | 357 | |
duke@435 | 358 | // Requires that "mr" be entirely within the space. |
duke@435 | 359 | // Apply "cl->do_object" to all objects that intersect with "mr". |
duke@435 | 360 | // If the iteration encounters an unparseable portion of the region, |
duke@435 | 361 | // terminate the iteration and return the address of the start of the |
duke@435 | 362 | // subregion that isn't done. Return of "NULL" indicates that the |
duke@435 | 363 | // interation completed. |
duke@435 | 364 | virtual HeapWord* |
duke@435 | 365 | object_iterate_careful_m(MemRegion mr, |
duke@435 | 366 | ObjectClosureCareful* cl); |
duke@435 | 367 | virtual HeapWord* |
duke@435 | 368 | object_iterate_careful(ObjectClosureCareful* cl); |
duke@435 | 369 | |
duke@435 | 370 | // Override: provides a DCTO_CL specific to this kind of space. |
duke@435 | 371 | DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, |
duke@435 | 372 | CardTableModRefBS::PrecisionStyle precision, |
duke@435 | 373 | HeapWord* boundary); |
duke@435 | 374 | |
duke@435 | 375 | void blk_iterate(BlkClosure* cl); |
duke@435 | 376 | void blk_iterate_careful(BlkClosureCareful* cl); |
ysr@777 | 377 | HeapWord* block_start_const(const void* p) const; |
duke@435 | 378 | HeapWord* block_start_careful(const void* p) const; |
duke@435 | 379 | size_t block_size(const HeapWord* p) const; |
duke@435 | 380 | size_t block_size_no_stall(HeapWord* p, const CMSCollector* c) const; |
duke@435 | 381 | bool block_is_obj(const HeapWord* p) const; |
duke@435 | 382 | bool obj_is_alive(const HeapWord* p) const; |
duke@435 | 383 | size_t block_size_nopar(const HeapWord* p) const; |
duke@435 | 384 | bool block_is_obj_nopar(const HeapWord* p) const; |
duke@435 | 385 | |
duke@435 | 386 | // iteration support for promotion |
duke@435 | 387 | void save_marks(); |
duke@435 | 388 | bool no_allocs_since_save_marks(); |
duke@435 | 389 | void object_iterate_since_last_GC(ObjectClosure* cl); |
duke@435 | 390 | |
duke@435 | 391 | // iteration support for sweeping |
duke@435 | 392 | void save_sweep_limit() { |
duke@435 | 393 | _sweep_limit = BlockOffsetArrayUseUnallocatedBlock ? |
duke@435 | 394 | unallocated_block() : end(); |
duke@435 | 395 | } |
duke@435 | 396 | NOT_PRODUCT( |
duke@435 | 397 | void clear_sweep_limit() { _sweep_limit = NULL; } |
duke@435 | 398 | ) |
duke@435 | 399 | HeapWord* sweep_limit() { return _sweep_limit; } |
duke@435 | 400 | |
duke@435 | 401 | // Apply "blk->do_oop" to the addresses of all reference fields in objects |
duke@435 | 402 | // promoted into this generation since the most recent save_marks() call. |
duke@435 | 403 | // Fields in objects allocated by applications of the closure |
duke@435 | 404 | // *are* included in the iteration. Thus, when the iteration completes |
duke@435 | 405 | // there should be no further such objects remaining. |
duke@435 | 406 | #define CFLS_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ |
duke@435 | 407 | void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); |
duke@435 | 408 | ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DECL) |
duke@435 | 409 | #undef CFLS_OOP_SINCE_SAVE_MARKS_DECL |
duke@435 | 410 | |
duke@435 | 411 | // Allocation support |
duke@435 | 412 | HeapWord* allocate(size_t size); |
duke@435 | 413 | HeapWord* par_allocate(size_t size); |
duke@435 | 414 | |
coleenp@548 | 415 | oop promote(oop obj, size_t obj_size); |
duke@435 | 416 | void gc_prologue(); |
duke@435 | 417 | void gc_epilogue(); |
duke@435 | 418 | |
duke@435 | 419 | // This call is used by a containing CMS generation / collector |
duke@435 | 420 | // to inform the CFLS space that a sweep has been completed |
duke@435 | 421 | // and that the space can do any related house-keeping functions. |
duke@435 | 422 | void sweep_completed(); |
duke@435 | 423 | |
duke@435 | 424 | // For an object in this space, the mark-word's two |
duke@435 | 425 | // LSB's having the value [11] indicates that it has been |
duke@435 | 426 | // promoted since the most recent call to save_marks() on |
duke@435 | 427 | // this generation and has not subsequently been iterated |
duke@435 | 428 | // over (using oop_since_save_marks_iterate() above). |
ysr@1876 | 429 | // This property holds only for single-threaded collections, |
ysr@1876 | 430 | // and is typically used for Cheney scans; for MT scavenges, |
ysr@1876 | 431 | // the property holds for all objects promoted during that |
ysr@1876 | 432 | // scavenge for the duration of the scavenge and is used |
ysr@1876 | 433 | // by card-scanning to avoid scanning objects (being) promoted |
ysr@1876 | 434 | // during that scavenge. |
duke@435 | 435 | bool obj_allocated_since_save_marks(const oop obj) const { |
duke@435 | 436 | assert(is_in_reserved(obj), "Wrong space?"); |
duke@435 | 437 | return ((PromotedObject*)obj)->hasPromotedMark(); |
duke@435 | 438 | } |
duke@435 | 439 | |
duke@435 | 440 | // A worst-case estimate of the space required (in HeapWords) to expand the |
duke@435 | 441 | // heap when promoting an obj of size obj_size. |
duke@435 | 442 | size_t expansionSpaceRequired(size_t obj_size) const; |
duke@435 | 443 | |
duke@435 | 444 | FreeChunk* allocateScratch(size_t size); |
duke@435 | 445 | |
duke@435 | 446 | // returns true if either the small or large linear allocation buffer is empty. |
ysr@447 | 447 | bool linearAllocationWouldFail() const; |
duke@435 | 448 | |
duke@435 | 449 | // Adjust the chunk for the minimum size. This version is called in |
duke@435 | 450 | // most cases in CompactibleFreeListSpace methods. |
duke@435 | 451 | inline static size_t adjustObjectSize(size_t size) { |
duke@435 | 452 | return (size_t) align_object_size(MAX2(size, (size_t)MinChunkSize)); |
duke@435 | 453 | } |
duke@435 | 454 | // This is a virtual version of adjustObjectSize() that is called |
duke@435 | 455 | // only occasionally when the compaction space changes and the type |
duke@435 | 456 | // of the new compaction space is is only known to be CompactibleSpace. |
duke@435 | 457 | size_t adjust_object_size_v(size_t size) const { |
duke@435 | 458 | return adjustObjectSize(size); |
duke@435 | 459 | } |
duke@435 | 460 | // Minimum size of a free block. |
duke@435 | 461 | virtual size_t minimum_free_block_size() const { return MinChunkSize; } |
duke@435 | 462 | void removeFreeChunkFromFreeLists(FreeChunk* chunk); |
duke@435 | 463 | void addChunkAndRepairOffsetTable(HeapWord* chunk, size_t size, |
duke@435 | 464 | bool coalesced); |
duke@435 | 465 | |
ysr@447 | 466 | // Support for decisions regarding concurrent collection policy |
ysr@447 | 467 | bool should_concurrent_collect() const; |
ysr@447 | 468 | |
duke@435 | 469 | // Support for compaction |
duke@435 | 470 | void prepare_for_compaction(CompactPoint* cp); |
duke@435 | 471 | void adjust_pointers(); |
duke@435 | 472 | void compact(); |
duke@435 | 473 | // reset the space to reflect the fact that a compaction of the |
duke@435 | 474 | // space has been done. |
duke@435 | 475 | virtual void reset_after_compaction(); |
duke@435 | 476 | |
duke@435 | 477 | // Debugging support |
duke@435 | 478 | void print() const; |
duke@435 | 479 | void prepare_for_verify(); |
duke@435 | 480 | void verify(bool allow_dirty) const; |
duke@435 | 481 | void verifyFreeLists() const PRODUCT_RETURN; |
duke@435 | 482 | void verifyIndexedFreeLists() const; |
duke@435 | 483 | void verifyIndexedFreeList(size_t size) const; |
duke@435 | 484 | // verify that the given chunk is in the free lists. |
duke@435 | 485 | bool verifyChunkInFreeLists(FreeChunk* fc) const; |
duke@435 | 486 | // Do some basic checks on the the free lists. |
duke@435 | 487 | void checkFreeListConsistency() const PRODUCT_RETURN; |
duke@435 | 488 | |
ysr@1580 | 489 | // Printing support |
ysr@1580 | 490 | void dump_at_safepoint_with_locks(CMSCollector* c, outputStream* st); |
ysr@1580 | 491 | void print_indexed_free_lists(outputStream* st) const; |
ysr@1580 | 492 | void print_dictionary_free_lists(outputStream* st) const; |
ysr@1580 | 493 | void print_promo_info_blocks(outputStream* st) const; |
ysr@1580 | 494 | |
duke@435 | 495 | NOT_PRODUCT ( |
duke@435 | 496 | void initializeIndexedFreeListArrayReturnedBytes(); |
duke@435 | 497 | size_t sumIndexedFreeListArrayReturnedBytes(); |
duke@435 | 498 | // Return the total number of chunks in the indexed free lists. |
duke@435 | 499 | size_t totalCountInIndexedFreeLists() const; |
duke@435 | 500 | // Return the total numberof chunks in the space. |
duke@435 | 501 | size_t totalCount(); |
duke@435 | 502 | ) |
duke@435 | 503 | |
duke@435 | 504 | // The census consists of counts of the quantities such as |
duke@435 | 505 | // the current count of the free chunks, number of chunks |
duke@435 | 506 | // created as a result of the split of a larger chunk or |
duke@435 | 507 | // coalescing of smaller chucks, etc. The counts in the |
duke@435 | 508 | // census is used to make decisions on splitting and |
duke@435 | 509 | // coalescing of chunks during the sweep of garbage. |
duke@435 | 510 | |
duke@435 | 511 | // Print the statistics for the free lists. |
ysr@447 | 512 | void printFLCensus(size_t sweep_count) const; |
duke@435 | 513 | |
duke@435 | 514 | // Statistics functions |
duke@435 | 515 | // Initialize census for lists before the sweep. |
ysr@1580 | 516 | void beginSweepFLCensus(float inter_sweep_current, |
ysr@1580 | 517 | float inter_sweep_estimate, |
ysr@1580 | 518 | float intra_sweep_estimate); |
duke@435 | 519 | // Set the surplus for each of the free lists. |
duke@435 | 520 | void setFLSurplus(); |
duke@435 | 521 | // Set the hint for each of the free lists. |
duke@435 | 522 | void setFLHints(); |
duke@435 | 523 | // Clear the census for each of the free lists. |
duke@435 | 524 | void clearFLCensus(); |
duke@435 | 525 | // Perform functions for the census after the end of the sweep. |
ysr@447 | 526 | void endSweepFLCensus(size_t sweep_count); |
duke@435 | 527 | // Return true if the count of free chunks is greater |
duke@435 | 528 | // than the desired number of free chunks. |
duke@435 | 529 | bool coalOverPopulated(size_t size); |
duke@435 | 530 | |
duke@435 | 531 | // Record (for each size): |
duke@435 | 532 | // |
duke@435 | 533 | // split-births = #chunks added due to splits in (prev-sweep-end, |
duke@435 | 534 | // this-sweep-start) |
duke@435 | 535 | // split-deaths = #chunks removed for splits in (prev-sweep-end, |
duke@435 | 536 | // this-sweep-start) |
duke@435 | 537 | // num-curr = #chunks at start of this sweep |
duke@435 | 538 | // num-prev = #chunks at end of previous sweep |
duke@435 | 539 | // |
duke@435 | 540 | // The above are quantities that are measured. Now define: |
duke@435 | 541 | // |
duke@435 | 542 | // num-desired := num-prev + split-births - split-deaths - num-curr |
duke@435 | 543 | // |
duke@435 | 544 | // Roughly, num-prev + split-births is the supply, |
duke@435 | 545 | // split-deaths is demand due to other sizes |
duke@435 | 546 | // and num-curr is what we have left. |
duke@435 | 547 | // |
duke@435 | 548 | // Thus, num-desired is roughly speaking the "legitimate demand" |
duke@435 | 549 | // for blocks of this size and what we are striving to reach at the |
duke@435 | 550 | // end of the current sweep. |
duke@435 | 551 | // |
duke@435 | 552 | // For a given list, let num-len be its current population. |
duke@435 | 553 | // Define, for a free list of a given size: |
duke@435 | 554 | // |
duke@435 | 555 | // coal-overpopulated := num-len >= num-desired * coal-surplus |
duke@435 | 556 | // (coal-surplus is set to 1.05, i.e. we allow a little slop when |
duke@435 | 557 | // coalescing -- we do not coalesce unless we think that the current |
duke@435 | 558 | // supply has exceeded the estimated demand by more than 5%). |
duke@435 | 559 | // |
duke@435 | 560 | // For the set of sizes in the binary tree, which is neither dense nor |
duke@435 | 561 | // closed, it may be the case that for a particular size we have never |
duke@435 | 562 | // had, or do not now have, or did not have at the previous sweep, |
duke@435 | 563 | // chunks of that size. We need to extend the definition of |
duke@435 | 564 | // coal-overpopulated to such sizes as well: |
duke@435 | 565 | // |
duke@435 | 566 | // For a chunk in/not in the binary tree, extend coal-overpopulated |
duke@435 | 567 | // defined above to include all sizes as follows: |
duke@435 | 568 | // |
duke@435 | 569 | // . a size that is non-existent is coal-overpopulated |
duke@435 | 570 | // . a size that has a num-desired <= 0 as defined above is |
duke@435 | 571 | // coal-overpopulated. |
duke@435 | 572 | // |
duke@435 | 573 | // Also define, for a chunk heap-offset C and mountain heap-offset M: |
duke@435 | 574 | // |
duke@435 | 575 | // close-to-mountain := C >= 0.99 * M |
duke@435 | 576 | // |
duke@435 | 577 | // Now, the coalescing strategy is: |
duke@435 | 578 | // |
duke@435 | 579 | // Coalesce left-hand chunk with right-hand chunk if and |
duke@435 | 580 | // only if: |
duke@435 | 581 | // |
duke@435 | 582 | // EITHER |
duke@435 | 583 | // . left-hand chunk is of a size that is coal-overpopulated |
duke@435 | 584 | // OR |
duke@435 | 585 | // . right-hand chunk is close-to-mountain |
duke@435 | 586 | void smallCoalBirth(size_t size); |
duke@435 | 587 | void smallCoalDeath(size_t size); |
duke@435 | 588 | void coalBirth(size_t size); |
duke@435 | 589 | void coalDeath(size_t size); |
duke@435 | 590 | void smallSplitBirth(size_t size); |
duke@435 | 591 | void smallSplitDeath(size_t size); |
duke@435 | 592 | void splitBirth(size_t size); |
duke@435 | 593 | void splitDeath(size_t size); |
duke@435 | 594 | void split(size_t from, size_t to1); |
duke@435 | 595 | |
duke@435 | 596 | double flsFrag() const; |
duke@435 | 597 | }; |
duke@435 | 598 | |
duke@435 | 599 | // A parallel-GC-thread-local allocation buffer for allocation into a |
duke@435 | 600 | // CompactibleFreeListSpace. |
duke@435 | 601 | class CFLS_LAB : public CHeapObj { |
duke@435 | 602 | // The space that this buffer allocates into. |
duke@435 | 603 | CompactibleFreeListSpace* _cfls; |
duke@435 | 604 | |
duke@435 | 605 | // Our local free lists. |
duke@435 | 606 | FreeList _indexedFreeList[CompactibleFreeListSpace::IndexSetSize]; |
duke@435 | 607 | |
duke@435 | 608 | // Initialized from a command-line arg. |
duke@435 | 609 | |
ysr@1580 | 610 | // Allocation statistics in support of dynamic adjustment of |
ysr@1580 | 611 | // #blocks to claim per get_from_global_pool() call below. |
ysr@1580 | 612 | static AdaptiveWeightedAverage |
ysr@1580 | 613 | _blocks_to_claim [CompactibleFreeListSpace::IndexSetSize]; |
ysr@1580 | 614 | static size_t _global_num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
ysr@1580 | 615 | static int _global_num_workers[CompactibleFreeListSpace::IndexSetSize]; |
ysr@1580 | 616 | size_t _num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
ysr@1580 | 617 | |
ysr@1580 | 618 | // Internal work method |
ysr@1580 | 619 | void get_from_global_pool(size_t word_sz, FreeList* fl); |
duke@435 | 620 | |
duke@435 | 621 | public: |
duke@435 | 622 | CFLS_LAB(CompactibleFreeListSpace* cfls); |
duke@435 | 623 | |
duke@435 | 624 | // Allocate and return a block of the given size, or else return NULL. |
duke@435 | 625 | HeapWord* alloc(size_t word_sz); |
duke@435 | 626 | |
duke@435 | 627 | // Return any unused portions of the buffer to the global pool. |
ysr@1580 | 628 | void retire(int tid); |
ysr@1580 | 629 | |
ysr@1580 | 630 | // Dynamic OldPLABSize sizing |
ysr@1580 | 631 | static void compute_desired_plab_size(); |
ysr@1580 | 632 | // When the settings are modified from default static initialization |
ysr@1580 | 633 | static void modify_initialization(size_t n, unsigned wt); |
duke@435 | 634 | }; |
duke@435 | 635 | |
duke@435 | 636 | size_t PromotionInfo::refillSize() const { |
duke@435 | 637 | const size_t CMSSpoolBlockSize = 256; |
duke@435 | 638 | const size_t sz = heap_word_size(sizeof(SpoolBlock) + sizeof(markOop) |
duke@435 | 639 | * CMSSpoolBlockSize); |
duke@435 | 640 | return CompactibleFreeListSpace::adjustObjectSize(sz); |
duke@435 | 641 | } |