Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp @ 1571:2d127394260e
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
author | kvn |
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date | Thu, 27 May 2010 18:01:56 -0700 |
parents | a8127dc669ba |
children | e9ff18c4ace7 |
rev | line source |
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0 | 1 /* |
579 | 2 * Copyright 2001-2009 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 // Classes in support of keeping track of promotions into a non-Contiguous | |
26 // space, in this case a CompactibleFreeListSpace. | |
27 | |
28 // Forward declarations | |
29 class CompactibleFreeListSpace; | |
30 class BlkClosure; | |
31 class BlkClosureCareful; | |
32 class UpwardsObjectClosure; | |
33 class ObjectClosureCareful; | |
34 class Klass; | |
35 | |
36 class LinearAllocBlock VALUE_OBJ_CLASS_SPEC { | |
37 public: | |
38 LinearAllocBlock() : _ptr(0), _word_size(0), _refillSize(0), | |
39 _allocation_size_limit(0) {} | |
40 void set(HeapWord* ptr, size_t word_size, size_t refill_size, | |
41 size_t allocation_size_limit) { | |
42 _ptr = ptr; | |
43 _word_size = word_size; | |
44 _refillSize = refill_size; | |
45 _allocation_size_limit = allocation_size_limit; | |
46 } | |
47 HeapWord* _ptr; | |
48 size_t _word_size; | |
49 size_t _refillSize; | |
50 size_t _allocation_size_limit; // largest size that will be allocated | |
51 }; | |
52 | |
53 // Concrete subclass of CompactibleSpace that implements | |
54 // a free list space, such as used in the concurrent mark sweep | |
55 // generation. | |
56 | |
57 class CompactibleFreeListSpace: public CompactibleSpace { | |
58 friend class VMStructs; | |
59 friend class ConcurrentMarkSweepGeneration; | |
60 friend class ASConcurrentMarkSweepGeneration; | |
61 friend class CMSCollector; | |
62 friend class CMSPermGenGen; | |
63 // Local alloc buffer for promotion into this space. | |
64 friend class CFLS_LAB; | |
65 | |
66 // "Size" of chunks of work (executed during parallel remark phases | |
67 // of CMS collection); this probably belongs in CMSCollector, although | |
68 // it's cached here because it's used in | |
69 // initialize_sequential_subtasks_for_rescan() which modifies | |
70 // par_seq_tasks which also lives in Space. XXX | |
71 const size_t _rescan_task_size; | |
72 const size_t _marking_task_size; | |
73 | |
74 // Yet another sequential tasks done structure. This supports | |
75 // CMS GC, where we have threads dynamically | |
76 // claiming sub-tasks from a larger parallel task. | |
77 SequentialSubTasksDone _conc_par_seq_tasks; | |
78 | |
79 BlockOffsetArrayNonContigSpace _bt; | |
80 | |
81 CMSCollector* _collector; | |
82 ConcurrentMarkSweepGeneration* _gen; | |
83 | |
84 // Data structures for free blocks (used during allocation/sweeping) | |
85 | |
86 // Allocation is done linearly from two different blocks depending on | |
87 // whether the request is small or large, in an effort to reduce | |
88 // fragmentation. We assume that any locking for allocation is done | |
89 // by the containing generation. Thus, none of the methods in this | |
90 // space are re-entrant. | |
91 enum SomeConstants { | |
92 SmallForLinearAlloc = 16, // size < this then use _sLAB | |
93 SmallForDictionary = 257, // size < this then use _indexedFreeList | |
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94 IndexSetSize = SmallForDictionary // keep this odd-sized |
0 | 95 }; |
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96 static int IndexSetStart; |
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97 static int IndexSetStride; |
0 | 98 |
99 private: | |
100 enum FitStrategyOptions { | |
101 FreeBlockStrategyNone = 0, | |
102 FreeBlockBestFitFirst | |
103 }; | |
104 | |
105 PromotionInfo _promoInfo; | |
106 | |
107 // helps to impose a global total order on freelistLock ranks; | |
108 // assumes that CFLSpace's are allocated in global total order | |
109 static int _lockRank; | |
110 | |
111 // a lock protecting the free lists and free blocks; | |
112 // mutable because of ubiquity of locking even for otherwise const methods | |
113 mutable Mutex _freelistLock; | |
114 // locking verifier convenience function | |
115 void assert_locked() const PRODUCT_RETURN; | |
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116 void assert_locked(const Mutex* lock) const PRODUCT_RETURN; |
0 | 117 |
118 // Linear allocation blocks | |
119 LinearAllocBlock _smallLinearAllocBlock; | |
120 | |
121 FreeBlockDictionary::DictionaryChoice _dictionaryChoice; | |
122 FreeBlockDictionary* _dictionary; // ptr to dictionary for large size blocks | |
123 | |
124 FreeList _indexedFreeList[IndexSetSize]; | |
125 // indexed array for small size blocks | |
126 // allocation stategy | |
127 bool _fitStrategy; // Use best fit strategy. | |
128 bool _adaptive_freelists; // Use adaptive freelists | |
129 | |
130 // This is an address close to the largest free chunk in the heap. | |
131 // It is currently assumed to be at the end of the heap. Free | |
132 // chunks with addresses greater than nearLargestChunk are coalesced | |
133 // in an effort to maintain a large chunk at the end of the heap. | |
134 HeapWord* _nearLargestChunk; | |
135 | |
136 // Used to keep track of limit of sweep for the space | |
137 HeapWord* _sweep_limit; | |
138 | |
139 // Support for compacting cms | |
140 HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
141 HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); | |
142 | |
143 // Initialization helpers. | |
144 void initializeIndexedFreeListArray(); | |
145 | |
146 // Extra stuff to manage promotion parallelism. | |
147 | |
148 // a lock protecting the dictionary during par promotion allocation. | |
149 mutable Mutex _parDictionaryAllocLock; | |
150 Mutex* parDictionaryAllocLock() const { return &_parDictionaryAllocLock; } | |
151 | |
152 // Locks protecting the exact lists during par promotion allocation. | |
153 Mutex* _indexedFreeListParLocks[IndexSetSize]; | |
154 | |
155 // Attempt to obtain up to "n" blocks of the size "word_sz" (which is | |
156 // required to be smaller than "IndexSetSize".) If successful, | |
157 // adds them to "fl", which is required to be an empty free list. | |
158 // If the count of "fl" is negative, it's absolute value indicates a | |
159 // number of free chunks that had been previously "borrowed" from global | |
160 // list of size "word_sz", and must now be decremented. | |
161 void par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl); | |
162 | |
163 // Allocation helper functions | |
164 // Allocate using a strategy that takes from the indexed free lists | |
165 // first. This allocation strategy assumes a companion sweeping | |
166 // strategy that attempts to keep the needed number of chunks in each | |
167 // indexed free lists. | |
168 HeapWord* allocate_adaptive_freelists(size_t size); | |
169 // Allocate from the linear allocation buffers first. This allocation | |
170 // strategy assumes maximal coalescing can maintain chunks large enough | |
171 // to be used as linear allocation buffers. | |
172 HeapWord* allocate_non_adaptive_freelists(size_t size); | |
173 | |
174 // Gets a chunk from the linear allocation block (LinAB). If there | |
175 // is not enough space in the LinAB, refills it. | |
176 HeapWord* getChunkFromLinearAllocBlock(LinearAllocBlock* blk, size_t size); | |
177 HeapWord* getChunkFromSmallLinearAllocBlock(size_t size); | |
178 // Get a chunk from the space remaining in the linear allocation block. Do | |
179 // not attempt to refill if the space is not available, return NULL. Do the | |
180 // repairs on the linear allocation block as appropriate. | |
181 HeapWord* getChunkFromLinearAllocBlockRemainder(LinearAllocBlock* blk, size_t size); | |
182 inline HeapWord* getChunkFromSmallLinearAllocBlockRemainder(size_t size); | |
183 | |
184 // Helper function for getChunkFromIndexedFreeList. | |
185 // Replenish the indexed free list for this "size". Do not take from an | |
186 // underpopulated size. | |
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187 FreeChunk* getChunkFromIndexedFreeListHelper(size_t size, bool replenish = true); |
0 | 188 |
189 // Get a chunk from the indexed free list. If the indexed free list | |
190 // does not have a free chunk, try to replenish the indexed free list | |
191 // then get the free chunk from the replenished indexed free list. | |
192 inline FreeChunk* getChunkFromIndexedFreeList(size_t size); | |
193 | |
194 // The returned chunk may be larger than requested (or null). | |
195 FreeChunk* getChunkFromDictionary(size_t size); | |
196 // The returned chunk is the exact size requested (or null). | |
197 FreeChunk* getChunkFromDictionaryExact(size_t size); | |
198 | |
199 // Find a chunk in the indexed free list that is the best | |
200 // fit for size "numWords". | |
201 FreeChunk* bestFitSmall(size_t numWords); | |
202 // For free list "fl" of chunks of size > numWords, | |
203 // remove a chunk, split off a chunk of size numWords | |
204 // and return it. The split off remainder is returned to | |
205 // the free lists. The old name for getFromListGreater | |
206 // was lookInListGreater. | |
207 FreeChunk* getFromListGreater(FreeList* fl, size_t numWords); | |
208 // Get a chunk in the indexed free list or dictionary, | |
209 // by considering a larger chunk and splitting it. | |
210 FreeChunk* getChunkFromGreater(size_t numWords); | |
211 // Verify that the given chunk is in the indexed free lists. | |
212 bool verifyChunkInIndexedFreeLists(FreeChunk* fc) const; | |
213 // Remove the specified chunk from the indexed free lists. | |
214 void removeChunkFromIndexedFreeList(FreeChunk* fc); | |
215 // Remove the specified chunk from the dictionary. | |
216 void removeChunkFromDictionary(FreeChunk* fc); | |
217 // Split a free chunk into a smaller free chunk of size "new_size". | |
218 // Return the smaller free chunk and return the remainder to the | |
219 // free lists. | |
220 FreeChunk* splitChunkAndReturnRemainder(FreeChunk* chunk, size_t new_size); | |
221 // Add a chunk to the free lists. | |
222 void addChunkToFreeLists(HeapWord* chunk, size_t size); | |
223 // Add a chunk to the free lists, preferring to suffix it | |
224 // to the last free chunk at end of space if possible, and | |
225 // updating the block census stats as well as block offset table. | |
226 // Take any locks as appropriate if we are multithreaded. | |
227 void addChunkToFreeListsAtEndRecordingStats(HeapWord* chunk, size_t size); | |
228 // Add a free chunk to the indexed free lists. | |
229 void returnChunkToFreeList(FreeChunk* chunk); | |
230 // Add a free chunk to the dictionary. | |
231 void returnChunkToDictionary(FreeChunk* chunk); | |
232 | |
233 // Functions for maintaining the linear allocation buffers (LinAB). | |
234 // Repairing a linear allocation block refers to operations | |
235 // performed on the remainder of a LinAB after an allocation | |
236 // has been made from it. | |
237 void repairLinearAllocationBlocks(); | |
238 void repairLinearAllocBlock(LinearAllocBlock* blk); | |
239 void refillLinearAllocBlock(LinearAllocBlock* blk); | |
240 void refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk); | |
241 void refillLinearAllocBlocksIfNeeded(); | |
242 | |
243 void verify_objects_initialized() const; | |
244 | |
245 // Statistics reporting helper functions | |
246 void reportFreeListStatistics() const; | |
247 void reportIndexedFreeListStatistics() const; | |
248 size_t maxChunkSizeInIndexedFreeLists() const; | |
249 size_t numFreeBlocksInIndexedFreeLists() const; | |
250 // Accessor | |
251 HeapWord* unallocated_block() const { | |
252 HeapWord* ub = _bt.unallocated_block(); | |
253 assert(ub >= bottom() && | |
254 ub <= end(), "space invariant"); | |
255 return ub; | |
256 } | |
257 void freed(HeapWord* start, size_t size) { | |
258 _bt.freed(start, size); | |
259 } | |
260 | |
261 protected: | |
262 // reset the indexed free list to its initial empty condition. | |
263 void resetIndexedFreeListArray(); | |
264 // reset to an initial state with a single free block described | |
265 // by the MemRegion parameter. | |
266 void reset(MemRegion mr); | |
267 // Return the total number of words in the indexed free lists. | |
268 size_t totalSizeInIndexedFreeLists() const; | |
269 | |
270 public: | |
271 // Constructor... | |
272 CompactibleFreeListSpace(BlockOffsetSharedArray* bs, MemRegion mr, | |
273 bool use_adaptive_freelists, | |
274 FreeBlockDictionary::DictionaryChoice); | |
275 // accessors | |
276 bool bestFitFirst() { return _fitStrategy == FreeBlockBestFitFirst; } | |
277 FreeBlockDictionary* dictionary() const { return _dictionary; } | |
278 HeapWord* nearLargestChunk() const { return _nearLargestChunk; } | |
279 void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; } | |
280 | |
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281 // Set CMS global values |
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282 static void set_cms_values(); |
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283 |
0 | 284 // Return the free chunk at the end of the space. If no such |
285 // chunk exists, return NULL. | |
286 FreeChunk* find_chunk_at_end(); | |
287 | |
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288 bool adaptive_freelists() const { return _adaptive_freelists; } |
0 | 289 |
290 void set_collector(CMSCollector* collector) { _collector = collector; } | |
291 | |
292 // Support for parallelization of rescan and marking | |
293 const size_t rescan_task_size() const { return _rescan_task_size; } | |
294 const size_t marking_task_size() const { return _marking_task_size; } | |
295 SequentialSubTasksDone* conc_par_seq_tasks() {return &_conc_par_seq_tasks; } | |
296 void initialize_sequential_subtasks_for_rescan(int n_threads); | |
297 void initialize_sequential_subtasks_for_marking(int n_threads, | |
298 HeapWord* low = NULL); | |
299 | |
300 // Space enquiries | |
301 size_t used() const; | |
302 size_t free() const; | |
303 size_t max_alloc_in_words() const; | |
304 // XXX: should have a less conservative used_region() than that of | |
305 // Space; we could consider keeping track of highest allocated | |
306 // address and correcting that at each sweep, as the sweeper | |
307 // goes through the entire allocated part of the generation. We | |
308 // could also use that information to keep the sweeper from | |
309 // sweeping more than is necessary. The allocator and sweeper will | |
310 // of course need to synchronize on this, since the sweeper will | |
311 // try to bump down the address and the allocator will try to bump it up. | |
312 // For now, however, we'll just use the default used_region() | |
313 // which overestimates the region by returning the entire | |
314 // committed region (this is safe, but inefficient). | |
315 | |
316 // Returns a subregion of the space containing all the objects in | |
317 // the space. | |
318 MemRegion used_region() const { | |
319 return MemRegion(bottom(), | |
320 BlockOffsetArrayUseUnallocatedBlock ? | |
321 unallocated_block() : end()); | |
322 } | |
323 | |
324 // This is needed because the default implementation uses block_start() | |
325 // which can;t be used at certain times (for example phase 3 of mark-sweep). | |
326 // A better fix is to change the assertions in phase 3 of mark-sweep to | |
327 // use is_in_reserved(), but that is deferred since the is_in() assertions | |
328 // are buried through several layers of callers and are used elsewhere | |
329 // as well. | |
330 bool is_in(const void* p) const { | |
331 return used_region().contains(p); | |
332 } | |
333 | |
334 virtual bool is_free_block(const HeapWord* p) const; | |
335 | |
336 // Resizing support | |
337 void set_end(HeapWord* value); // override | |
338 | |
339 // mutual exclusion support | |
340 Mutex* freelistLock() const { return &_freelistLock; } | |
341 | |
342 // Iteration support | |
343 void oop_iterate(MemRegion mr, OopClosure* cl); | |
344 void oop_iterate(OopClosure* cl); | |
345 | |
346 void object_iterate(ObjectClosure* blk); | |
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347 // Apply the closure to each object in the space whose references |
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348 // point to objects in the heap. The usage of CompactibleFreeListSpace |
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349 // by the ConcurrentMarkSweepGeneration for concurrent GC's allows |
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350 // objects in the space with references to objects that are no longer |
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351 // valid. For example, an object may reference another object |
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352 // that has already been sweep up (collected). This method uses |
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353 // obj_is_alive() to determine whether it is safe to iterate of |
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354 // an object. |
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355 void safe_object_iterate(ObjectClosure* blk); |
0 | 356 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
357 | |
358 // Requires that "mr" be entirely within the space. | |
359 // Apply "cl->do_object" to all objects that intersect with "mr". | |
360 // If the iteration encounters an unparseable portion of the region, | |
361 // terminate the iteration and return the address of the start of the | |
362 // subregion that isn't done. Return of "NULL" indicates that the | |
363 // interation completed. | |
364 virtual HeapWord* | |
365 object_iterate_careful_m(MemRegion mr, | |
366 ObjectClosureCareful* cl); | |
367 virtual HeapWord* | |
368 object_iterate_careful(ObjectClosureCareful* cl); | |
369 | |
370 // Override: provides a DCTO_CL specific to this kind of space. | |
371 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
372 CardTableModRefBS::PrecisionStyle precision, | |
373 HeapWord* boundary); | |
374 | |
375 void blk_iterate(BlkClosure* cl); | |
376 void blk_iterate_careful(BlkClosureCareful* cl); | |
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377 HeapWord* block_start_const(const void* p) const; |
0 | 378 HeapWord* block_start_careful(const void* p) const; |
379 size_t block_size(const HeapWord* p) const; | |
380 size_t block_size_no_stall(HeapWord* p, const CMSCollector* c) const; | |
381 bool block_is_obj(const HeapWord* p) const; | |
382 bool obj_is_alive(const HeapWord* p) const; | |
383 size_t block_size_nopar(const HeapWord* p) const; | |
384 bool block_is_obj_nopar(const HeapWord* p) const; | |
385 | |
386 // iteration support for promotion | |
387 void save_marks(); | |
388 bool no_allocs_since_save_marks(); | |
389 void object_iterate_since_last_GC(ObjectClosure* cl); | |
390 | |
391 // iteration support for sweeping | |
392 void save_sweep_limit() { | |
393 _sweep_limit = BlockOffsetArrayUseUnallocatedBlock ? | |
394 unallocated_block() : end(); | |
395 } | |
396 NOT_PRODUCT( | |
397 void clear_sweep_limit() { _sweep_limit = NULL; } | |
398 ) | |
399 HeapWord* sweep_limit() { return _sweep_limit; } | |
400 | |
401 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
402 // promoted into this generation since the most recent save_marks() call. | |
403 // Fields in objects allocated by applications of the closure | |
404 // *are* included in the iteration. Thus, when the iteration completes | |
405 // there should be no further such objects remaining. | |
406 #define CFLS_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
407 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
408 ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DECL) | |
409 #undef CFLS_OOP_SINCE_SAVE_MARKS_DECL | |
410 | |
411 // Allocation support | |
412 HeapWord* allocate(size_t size); | |
413 HeapWord* par_allocate(size_t size); | |
414 | |
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415 oop promote(oop obj, size_t obj_size); |
0 | 416 void gc_prologue(); |
417 void gc_epilogue(); | |
418 | |
419 // This call is used by a containing CMS generation / collector | |
420 // to inform the CFLS space that a sweep has been completed | |
421 // and that the space can do any related house-keeping functions. | |
422 void sweep_completed(); | |
423 | |
424 // For an object in this space, the mark-word's two | |
425 // LSB's having the value [11] indicates that it has been | |
426 // promoted since the most recent call to save_marks() on | |
427 // this generation and has not subsequently been iterated | |
428 // over (using oop_since_save_marks_iterate() above). | |
1521 | 429 // This property holds only for single-threaded collections, |
430 // and is typically used for Cheney scans; for MT scavenges, | |
431 // the property holds for all objects promoted during that | |
432 // scavenge for the duration of the scavenge and is used | |
433 // by card-scanning to avoid scanning objects (being) promoted | |
434 // during that scavenge. | |
0 | 435 bool obj_allocated_since_save_marks(const oop obj) const { |
436 assert(is_in_reserved(obj), "Wrong space?"); | |
437 return ((PromotedObject*)obj)->hasPromotedMark(); | |
438 } | |
439 | |
440 // A worst-case estimate of the space required (in HeapWords) to expand the | |
441 // heap when promoting an obj of size obj_size. | |
442 size_t expansionSpaceRequired(size_t obj_size) const; | |
443 | |
444 FreeChunk* allocateScratch(size_t size); | |
445 | |
446 // returns true if either the small or large linear allocation buffer is empty. | |
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447 bool linearAllocationWouldFail() const; |
0 | 448 |
449 // Adjust the chunk for the minimum size. This version is called in | |
450 // most cases in CompactibleFreeListSpace methods. | |
451 inline static size_t adjustObjectSize(size_t size) { | |
452 return (size_t) align_object_size(MAX2(size, (size_t)MinChunkSize)); | |
453 } | |
454 // This is a virtual version of adjustObjectSize() that is called | |
455 // only occasionally when the compaction space changes and the type | |
456 // of the new compaction space is is only known to be CompactibleSpace. | |
457 size_t adjust_object_size_v(size_t size) const { | |
458 return adjustObjectSize(size); | |
459 } | |
460 // Minimum size of a free block. | |
461 virtual size_t minimum_free_block_size() const { return MinChunkSize; } | |
462 void removeFreeChunkFromFreeLists(FreeChunk* chunk); | |
463 void addChunkAndRepairOffsetTable(HeapWord* chunk, size_t size, | |
464 bool coalesced); | |
465 | |
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466 // Support for decisions regarding concurrent collection policy |
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467 bool should_concurrent_collect() const; |
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468 |
0 | 469 // Support for compaction |
470 void prepare_for_compaction(CompactPoint* cp); | |
471 void adjust_pointers(); | |
472 void compact(); | |
473 // reset the space to reflect the fact that a compaction of the | |
474 // space has been done. | |
475 virtual void reset_after_compaction(); | |
476 | |
477 // Debugging support | |
478 void print() const; | |
479 void prepare_for_verify(); | |
480 void verify(bool allow_dirty) const; | |
481 void verifyFreeLists() const PRODUCT_RETURN; | |
482 void verifyIndexedFreeLists() const; | |
483 void verifyIndexedFreeList(size_t size) const; | |
484 // verify that the given chunk is in the free lists. | |
485 bool verifyChunkInFreeLists(FreeChunk* fc) const; | |
486 // Do some basic checks on the the free lists. | |
487 void checkFreeListConsistency() const PRODUCT_RETURN; | |
488 | |
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489 // Printing support |
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490 void dump_at_safepoint_with_locks(CMSCollector* c, outputStream* st); |
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491 void print_indexed_free_lists(outputStream* st) const; |
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492 void print_dictionary_free_lists(outputStream* st) const; |
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493 void print_promo_info_blocks(outputStream* st) const; |
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494 |
0 | 495 NOT_PRODUCT ( |
496 void initializeIndexedFreeListArrayReturnedBytes(); | |
497 size_t sumIndexedFreeListArrayReturnedBytes(); | |
498 // Return the total number of chunks in the indexed free lists. | |
499 size_t totalCountInIndexedFreeLists() const; | |
500 // Return the total numberof chunks in the space. | |
501 size_t totalCount(); | |
502 ) | |
503 | |
504 // The census consists of counts of the quantities such as | |
505 // the current count of the free chunks, number of chunks | |
506 // created as a result of the split of a larger chunk or | |
507 // coalescing of smaller chucks, etc. The counts in the | |
508 // census is used to make decisions on splitting and | |
509 // coalescing of chunks during the sweep of garbage. | |
510 | |
511 // Print the statistics for the free lists. | |
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512 void printFLCensus(size_t sweep_count) const; |
0 | 513 |
514 // Statistics functions | |
515 // Initialize census for lists before the sweep. | |
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516 void beginSweepFLCensus(float inter_sweep_current, |
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517 float inter_sweep_estimate, |
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518 float intra_sweep_estimate); |
0 | 519 // Set the surplus for each of the free lists. |
520 void setFLSurplus(); | |
521 // Set the hint for each of the free lists. | |
522 void setFLHints(); | |
523 // Clear the census for each of the free lists. | |
524 void clearFLCensus(); | |
525 // Perform functions for the census after the end of the sweep. | |
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526 void endSweepFLCensus(size_t sweep_count); |
0 | 527 // Return true if the count of free chunks is greater |
528 // than the desired number of free chunks. | |
529 bool coalOverPopulated(size_t size); | |
530 | |
531 // Record (for each size): | |
532 // | |
533 // split-births = #chunks added due to splits in (prev-sweep-end, | |
534 // this-sweep-start) | |
535 // split-deaths = #chunks removed for splits in (prev-sweep-end, | |
536 // this-sweep-start) | |
537 // num-curr = #chunks at start of this sweep | |
538 // num-prev = #chunks at end of previous sweep | |
539 // | |
540 // The above are quantities that are measured. Now define: | |
541 // | |
542 // num-desired := num-prev + split-births - split-deaths - num-curr | |
543 // | |
544 // Roughly, num-prev + split-births is the supply, | |
545 // split-deaths is demand due to other sizes | |
546 // and num-curr is what we have left. | |
547 // | |
548 // Thus, num-desired is roughly speaking the "legitimate demand" | |
549 // for blocks of this size and what we are striving to reach at the | |
550 // end of the current sweep. | |
551 // | |
552 // For a given list, let num-len be its current population. | |
553 // Define, for a free list of a given size: | |
554 // | |
555 // coal-overpopulated := num-len >= num-desired * coal-surplus | |
556 // (coal-surplus is set to 1.05, i.e. we allow a little slop when | |
557 // coalescing -- we do not coalesce unless we think that the current | |
558 // supply has exceeded the estimated demand by more than 5%). | |
559 // | |
560 // For the set of sizes in the binary tree, which is neither dense nor | |
561 // closed, it may be the case that for a particular size we have never | |
562 // had, or do not now have, or did not have at the previous sweep, | |
563 // chunks of that size. We need to extend the definition of | |
564 // coal-overpopulated to such sizes as well: | |
565 // | |
566 // For a chunk in/not in the binary tree, extend coal-overpopulated | |
567 // defined above to include all sizes as follows: | |
568 // | |
569 // . a size that is non-existent is coal-overpopulated | |
570 // . a size that has a num-desired <= 0 as defined above is | |
571 // coal-overpopulated. | |
572 // | |
573 // Also define, for a chunk heap-offset C and mountain heap-offset M: | |
574 // | |
575 // close-to-mountain := C >= 0.99 * M | |
576 // | |
577 // Now, the coalescing strategy is: | |
578 // | |
579 // Coalesce left-hand chunk with right-hand chunk if and | |
580 // only if: | |
581 // | |
582 // EITHER | |
583 // . left-hand chunk is of a size that is coal-overpopulated | |
584 // OR | |
585 // . right-hand chunk is close-to-mountain | |
586 void smallCoalBirth(size_t size); | |
587 void smallCoalDeath(size_t size); | |
588 void coalBirth(size_t size); | |
589 void coalDeath(size_t size); | |
590 void smallSplitBirth(size_t size); | |
591 void smallSplitDeath(size_t size); | |
592 void splitBirth(size_t size); | |
593 void splitDeath(size_t size); | |
594 void split(size_t from, size_t to1); | |
595 | |
596 double flsFrag() const; | |
597 }; | |
598 | |
599 // A parallel-GC-thread-local allocation buffer for allocation into a | |
600 // CompactibleFreeListSpace. | |
601 class CFLS_LAB : public CHeapObj { | |
602 // The space that this buffer allocates into. | |
603 CompactibleFreeListSpace* _cfls; | |
604 | |
605 // Our local free lists. | |
606 FreeList _indexedFreeList[CompactibleFreeListSpace::IndexSetSize]; | |
607 | |
608 // Initialized from a command-line arg. | |
609 | |
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610 // Allocation statistics in support of dynamic adjustment of |
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611 // #blocks to claim per get_from_global_pool() call below. |
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612 static AdaptiveWeightedAverage |
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613 _blocks_to_claim [CompactibleFreeListSpace::IndexSetSize]; |
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614 static size_t _global_num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
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615 static int _global_num_workers[CompactibleFreeListSpace::IndexSetSize]; |
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616 size_t _num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
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617 |
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618 // Internal work method |
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619 void get_from_global_pool(size_t word_sz, FreeList* fl); |
0 | 620 |
621 public: | |
622 CFLS_LAB(CompactibleFreeListSpace* cfls); | |
623 | |
624 // Allocate and return a block of the given size, or else return NULL. | |
625 HeapWord* alloc(size_t word_sz); | |
626 | |
627 // Return any unused portions of the buffer to the global pool. | |
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628 void retire(int tid); |
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629 |
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630 // Dynamic OldPLABSize sizing |
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631 static void compute_desired_plab_size(); |
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632 // When the settings are modified from default static initialization |
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633 static void modify_initialization(size_t n, unsigned wt); |
0 | 634 }; |
635 | |
636 size_t PromotionInfo::refillSize() const { | |
637 const size_t CMSSpoolBlockSize = 256; | |
638 const size_t sz = heap_word_size(sizeof(SpoolBlock) + sizeof(markOop) | |
639 * CMSSpoolBlockSize); | |
640 return CompactibleFreeListSpace::adjustObjectSize(sz); | |
641 } |