Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp @ 2045:9c96c873c42b
Fix includes to match new hotspot mechanism.
author | Thomas Wuerthinger <wuerthinger@ssw.jku.at> |
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date | Fri, 07 Jan 2011 18:45:09 +0100 |
parents | f95d63e2154a |
children | 8cbcd406c42e |
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0 | 1 /* |
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2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP | |
27 | |
28 #include "gc_implementation/concurrentMarkSweep/binaryTreeDictionary.hpp" | |
29 #include "gc_implementation/concurrentMarkSweep/freeList.hpp" | |
30 #include "gc_implementation/concurrentMarkSweep/promotionInfo.hpp" | |
31 #include "memory/blockOffsetTable.inline.hpp" | |
32 #include "memory/space.hpp" | |
33 | |
0 | 34 // Classes in support of keeping track of promotions into a non-Contiguous |
35 // space, in this case a CompactibleFreeListSpace. | |
36 | |
37 // Forward declarations | |
38 class CompactibleFreeListSpace; | |
39 class BlkClosure; | |
40 class BlkClosureCareful; | |
41 class UpwardsObjectClosure; | |
42 class ObjectClosureCareful; | |
43 class Klass; | |
44 | |
45 class LinearAllocBlock VALUE_OBJ_CLASS_SPEC { | |
46 public: | |
47 LinearAllocBlock() : _ptr(0), _word_size(0), _refillSize(0), | |
48 _allocation_size_limit(0) {} | |
49 void set(HeapWord* ptr, size_t word_size, size_t refill_size, | |
50 size_t allocation_size_limit) { | |
51 _ptr = ptr; | |
52 _word_size = word_size; | |
53 _refillSize = refill_size; | |
54 _allocation_size_limit = allocation_size_limit; | |
55 } | |
56 HeapWord* _ptr; | |
57 size_t _word_size; | |
58 size_t _refillSize; | |
59 size_t _allocation_size_limit; // largest size that will be allocated | |
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60 |
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61 void print_on(outputStream* st) const; |
0 | 62 }; |
63 | |
64 // Concrete subclass of CompactibleSpace that implements | |
65 // a free list space, such as used in the concurrent mark sweep | |
66 // generation. | |
67 | |
68 class CompactibleFreeListSpace: public CompactibleSpace { | |
69 friend class VMStructs; | |
70 friend class ConcurrentMarkSweepGeneration; | |
71 friend class ASConcurrentMarkSweepGeneration; | |
72 friend class CMSCollector; | |
73 friend class CMSPermGenGen; | |
74 // Local alloc buffer for promotion into this space. | |
75 friend class CFLS_LAB; | |
76 | |
77 // "Size" of chunks of work (executed during parallel remark phases | |
78 // of CMS collection); this probably belongs in CMSCollector, although | |
79 // it's cached here because it's used in | |
80 // initialize_sequential_subtasks_for_rescan() which modifies | |
81 // par_seq_tasks which also lives in Space. XXX | |
82 const size_t _rescan_task_size; | |
83 const size_t _marking_task_size; | |
84 | |
85 // Yet another sequential tasks done structure. This supports | |
86 // CMS GC, where we have threads dynamically | |
87 // claiming sub-tasks from a larger parallel task. | |
88 SequentialSubTasksDone _conc_par_seq_tasks; | |
89 | |
90 BlockOffsetArrayNonContigSpace _bt; | |
91 | |
92 CMSCollector* _collector; | |
93 ConcurrentMarkSweepGeneration* _gen; | |
94 | |
95 // Data structures for free blocks (used during allocation/sweeping) | |
96 | |
97 // Allocation is done linearly from two different blocks depending on | |
98 // whether the request is small or large, in an effort to reduce | |
99 // fragmentation. We assume that any locking for allocation is done | |
100 // by the containing generation. Thus, none of the methods in this | |
101 // space are re-entrant. | |
102 enum SomeConstants { | |
103 SmallForLinearAlloc = 16, // size < this then use _sLAB | |
104 SmallForDictionary = 257, // size < this then use _indexedFreeList | |
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105 IndexSetSize = SmallForDictionary // keep this odd-sized |
0 | 106 }; |
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107 static int IndexSetStart; |
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108 static int IndexSetStride; |
0 | 109 |
110 private: | |
111 enum FitStrategyOptions { | |
112 FreeBlockStrategyNone = 0, | |
113 FreeBlockBestFitFirst | |
114 }; | |
115 | |
116 PromotionInfo _promoInfo; | |
117 | |
118 // helps to impose a global total order on freelistLock ranks; | |
119 // assumes that CFLSpace's are allocated in global total order | |
120 static int _lockRank; | |
121 | |
122 // a lock protecting the free lists and free blocks; | |
123 // mutable because of ubiquity of locking even for otherwise const methods | |
124 mutable Mutex _freelistLock; | |
125 // locking verifier convenience function | |
126 void assert_locked() const PRODUCT_RETURN; | |
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127 void assert_locked(const Mutex* lock) const PRODUCT_RETURN; |
0 | 128 |
129 // Linear allocation blocks | |
130 LinearAllocBlock _smallLinearAllocBlock; | |
131 | |
132 FreeBlockDictionary::DictionaryChoice _dictionaryChoice; | |
133 FreeBlockDictionary* _dictionary; // ptr to dictionary for large size blocks | |
134 | |
135 FreeList _indexedFreeList[IndexSetSize]; | |
136 // indexed array for small size blocks | |
137 // allocation stategy | |
138 bool _fitStrategy; // Use best fit strategy. | |
139 bool _adaptive_freelists; // Use adaptive freelists | |
140 | |
141 // This is an address close to the largest free chunk in the heap. | |
142 // It is currently assumed to be at the end of the heap. Free | |
143 // chunks with addresses greater than nearLargestChunk are coalesced | |
144 // in an effort to maintain a large chunk at the end of the heap. | |
145 HeapWord* _nearLargestChunk; | |
146 | |
147 // Used to keep track of limit of sweep for the space | |
148 HeapWord* _sweep_limit; | |
149 | |
150 // Support for compacting cms | |
151 HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
152 HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); | |
153 | |
154 // Initialization helpers. | |
155 void initializeIndexedFreeListArray(); | |
156 | |
157 // Extra stuff to manage promotion parallelism. | |
158 | |
159 // a lock protecting the dictionary during par promotion allocation. | |
160 mutable Mutex _parDictionaryAllocLock; | |
161 Mutex* parDictionaryAllocLock() const { return &_parDictionaryAllocLock; } | |
162 | |
163 // Locks protecting the exact lists during par promotion allocation. | |
164 Mutex* _indexedFreeListParLocks[IndexSetSize]; | |
165 | |
166 // Attempt to obtain up to "n" blocks of the size "word_sz" (which is | |
167 // required to be smaller than "IndexSetSize".) If successful, | |
168 // adds them to "fl", which is required to be an empty free list. | |
169 // If the count of "fl" is negative, it's absolute value indicates a | |
170 // number of free chunks that had been previously "borrowed" from global | |
171 // list of size "word_sz", and must now be decremented. | |
172 void par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl); | |
173 | |
174 // Allocation helper functions | |
175 // Allocate using a strategy that takes from the indexed free lists | |
176 // first. This allocation strategy assumes a companion sweeping | |
177 // strategy that attempts to keep the needed number of chunks in each | |
178 // indexed free lists. | |
179 HeapWord* allocate_adaptive_freelists(size_t size); | |
180 // Allocate from the linear allocation buffers first. This allocation | |
181 // strategy assumes maximal coalescing can maintain chunks large enough | |
182 // to be used as linear allocation buffers. | |
183 HeapWord* allocate_non_adaptive_freelists(size_t size); | |
184 | |
185 // Gets a chunk from the linear allocation block (LinAB). If there | |
186 // is not enough space in the LinAB, refills it. | |
187 HeapWord* getChunkFromLinearAllocBlock(LinearAllocBlock* blk, size_t size); | |
188 HeapWord* getChunkFromSmallLinearAllocBlock(size_t size); | |
189 // Get a chunk from the space remaining in the linear allocation block. Do | |
190 // not attempt to refill if the space is not available, return NULL. Do the | |
191 // repairs on the linear allocation block as appropriate. | |
192 HeapWord* getChunkFromLinearAllocBlockRemainder(LinearAllocBlock* blk, size_t size); | |
193 inline HeapWord* getChunkFromSmallLinearAllocBlockRemainder(size_t size); | |
194 | |
195 // Helper function for getChunkFromIndexedFreeList. | |
196 // Replenish the indexed free list for this "size". Do not take from an | |
197 // underpopulated size. | |
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198 FreeChunk* getChunkFromIndexedFreeListHelper(size_t size, bool replenish = true); |
0 | 199 |
200 // Get a chunk from the indexed free list. If the indexed free list | |
201 // does not have a free chunk, try to replenish the indexed free list | |
202 // then get the free chunk from the replenished indexed free list. | |
203 inline FreeChunk* getChunkFromIndexedFreeList(size_t size); | |
204 | |
205 // The returned chunk may be larger than requested (or null). | |
206 FreeChunk* getChunkFromDictionary(size_t size); | |
207 // The returned chunk is the exact size requested (or null). | |
208 FreeChunk* getChunkFromDictionaryExact(size_t size); | |
209 | |
210 // Find a chunk in the indexed free list that is the best | |
211 // fit for size "numWords". | |
212 FreeChunk* bestFitSmall(size_t numWords); | |
213 // For free list "fl" of chunks of size > numWords, | |
214 // remove a chunk, split off a chunk of size numWords | |
215 // and return it. The split off remainder is returned to | |
216 // the free lists. The old name for getFromListGreater | |
217 // was lookInListGreater. | |
218 FreeChunk* getFromListGreater(FreeList* fl, size_t numWords); | |
219 // Get a chunk in the indexed free list or dictionary, | |
220 // by considering a larger chunk and splitting it. | |
221 FreeChunk* getChunkFromGreater(size_t numWords); | |
222 // Verify that the given chunk is in the indexed free lists. | |
223 bool verifyChunkInIndexedFreeLists(FreeChunk* fc) const; | |
224 // Remove the specified chunk from the indexed free lists. | |
225 void removeChunkFromIndexedFreeList(FreeChunk* fc); | |
226 // Remove the specified chunk from the dictionary. | |
227 void removeChunkFromDictionary(FreeChunk* fc); | |
228 // Split a free chunk into a smaller free chunk of size "new_size". | |
229 // Return the smaller free chunk and return the remainder to the | |
230 // free lists. | |
231 FreeChunk* splitChunkAndReturnRemainder(FreeChunk* chunk, size_t new_size); | |
232 // Add a chunk to the free lists. | |
233 void addChunkToFreeLists(HeapWord* chunk, size_t size); | |
234 // Add a chunk to the free lists, preferring to suffix it | |
235 // to the last free chunk at end of space if possible, and | |
236 // updating the block census stats as well as block offset table. | |
237 // Take any locks as appropriate if we are multithreaded. | |
238 void addChunkToFreeListsAtEndRecordingStats(HeapWord* chunk, size_t size); | |
239 // Add a free chunk to the indexed free lists. | |
240 void returnChunkToFreeList(FreeChunk* chunk); | |
241 // Add a free chunk to the dictionary. | |
242 void returnChunkToDictionary(FreeChunk* chunk); | |
243 | |
244 // Functions for maintaining the linear allocation buffers (LinAB). | |
245 // Repairing a linear allocation block refers to operations | |
246 // performed on the remainder of a LinAB after an allocation | |
247 // has been made from it. | |
248 void repairLinearAllocationBlocks(); | |
249 void repairLinearAllocBlock(LinearAllocBlock* blk); | |
250 void refillLinearAllocBlock(LinearAllocBlock* blk); | |
251 void refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk); | |
252 void refillLinearAllocBlocksIfNeeded(); | |
253 | |
254 void verify_objects_initialized() const; | |
255 | |
256 // Statistics reporting helper functions | |
257 void reportFreeListStatistics() const; | |
258 void reportIndexedFreeListStatistics() const; | |
259 size_t maxChunkSizeInIndexedFreeLists() const; | |
260 size_t numFreeBlocksInIndexedFreeLists() const; | |
261 // Accessor | |
262 HeapWord* unallocated_block() const { | |
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263 if (BlockOffsetArrayUseUnallocatedBlock) { |
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264 HeapWord* ub = _bt.unallocated_block(); |
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265 assert(ub >= bottom() && |
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266 ub <= end(), "space invariant"); |
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267 return ub; |
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268 } else { |
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269 return end(); |
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270 } |
0 | 271 } |
272 void freed(HeapWord* start, size_t size) { | |
273 _bt.freed(start, size); | |
274 } | |
275 | |
276 protected: | |
277 // reset the indexed free list to its initial empty condition. | |
278 void resetIndexedFreeListArray(); | |
279 // reset to an initial state with a single free block described | |
280 // by the MemRegion parameter. | |
281 void reset(MemRegion mr); | |
282 // Return the total number of words in the indexed free lists. | |
283 size_t totalSizeInIndexedFreeLists() const; | |
284 | |
285 public: | |
286 // Constructor... | |
287 CompactibleFreeListSpace(BlockOffsetSharedArray* bs, MemRegion mr, | |
288 bool use_adaptive_freelists, | |
289 FreeBlockDictionary::DictionaryChoice); | |
290 // accessors | |
291 bool bestFitFirst() { return _fitStrategy == FreeBlockBestFitFirst; } | |
292 FreeBlockDictionary* dictionary() const { return _dictionary; } | |
293 HeapWord* nearLargestChunk() const { return _nearLargestChunk; } | |
294 void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; } | |
295 | |
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296 // Set CMS global values |
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297 static void set_cms_values(); |
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298 |
0 | 299 // Return the free chunk at the end of the space. If no such |
300 // chunk exists, return NULL. | |
301 FreeChunk* find_chunk_at_end(); | |
302 | |
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303 bool adaptive_freelists() const { return _adaptive_freelists; } |
0 | 304 |
305 void set_collector(CMSCollector* collector) { _collector = collector; } | |
306 | |
307 // Support for parallelization of rescan and marking | |
308 const size_t rescan_task_size() const { return _rescan_task_size; } | |
309 const size_t marking_task_size() const { return _marking_task_size; } | |
310 SequentialSubTasksDone* conc_par_seq_tasks() {return &_conc_par_seq_tasks; } | |
311 void initialize_sequential_subtasks_for_rescan(int n_threads); | |
312 void initialize_sequential_subtasks_for_marking(int n_threads, | |
313 HeapWord* low = NULL); | |
314 | |
315 // Space enquiries | |
316 size_t used() const; | |
317 size_t free() const; | |
318 size_t max_alloc_in_words() const; | |
319 // XXX: should have a less conservative used_region() than that of | |
320 // Space; we could consider keeping track of highest allocated | |
321 // address and correcting that at each sweep, as the sweeper | |
322 // goes through the entire allocated part of the generation. We | |
323 // could also use that information to keep the sweeper from | |
324 // sweeping more than is necessary. The allocator and sweeper will | |
325 // of course need to synchronize on this, since the sweeper will | |
326 // try to bump down the address and the allocator will try to bump it up. | |
327 // For now, however, we'll just use the default used_region() | |
328 // which overestimates the region by returning the entire | |
329 // committed region (this is safe, but inefficient). | |
330 | |
331 // Returns a subregion of the space containing all the objects in | |
332 // the space. | |
333 MemRegion used_region() const { | |
334 return MemRegion(bottom(), | |
335 BlockOffsetArrayUseUnallocatedBlock ? | |
336 unallocated_block() : end()); | |
337 } | |
338 | |
339 // This is needed because the default implementation uses block_start() | |
340 // which can;t be used at certain times (for example phase 3 of mark-sweep). | |
341 // A better fix is to change the assertions in phase 3 of mark-sweep to | |
342 // use is_in_reserved(), but that is deferred since the is_in() assertions | |
343 // are buried through several layers of callers and are used elsewhere | |
344 // as well. | |
345 bool is_in(const void* p) const { | |
346 return used_region().contains(p); | |
347 } | |
348 | |
349 virtual bool is_free_block(const HeapWord* p) const; | |
350 | |
351 // Resizing support | |
352 void set_end(HeapWord* value); // override | |
353 | |
354 // mutual exclusion support | |
355 Mutex* freelistLock() const { return &_freelistLock; } | |
356 | |
357 // Iteration support | |
358 void oop_iterate(MemRegion mr, OopClosure* cl); | |
359 void oop_iterate(OopClosure* cl); | |
360 | |
361 void object_iterate(ObjectClosure* blk); | |
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362 // Apply the closure to each object in the space whose references |
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363 // point to objects in the heap. The usage of CompactibleFreeListSpace |
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364 // by the ConcurrentMarkSweepGeneration for concurrent GC's allows |
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365 // objects in the space with references to objects that are no longer |
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366 // valid. For example, an object may reference another object |
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367 // that has already been sweep up (collected). This method uses |
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368 // obj_is_alive() to determine whether it is safe to iterate of |
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369 // an object. |
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370 void safe_object_iterate(ObjectClosure* blk); |
0 | 371 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
372 | |
373 // Requires that "mr" be entirely within the space. | |
374 // Apply "cl->do_object" to all objects that intersect with "mr". | |
375 // If the iteration encounters an unparseable portion of the region, | |
376 // terminate the iteration and return the address of the start of the | |
377 // subregion that isn't done. Return of "NULL" indicates that the | |
378 // interation completed. | |
379 virtual HeapWord* | |
380 object_iterate_careful_m(MemRegion mr, | |
381 ObjectClosureCareful* cl); | |
382 virtual HeapWord* | |
383 object_iterate_careful(ObjectClosureCareful* cl); | |
384 | |
385 // Override: provides a DCTO_CL specific to this kind of space. | |
386 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
387 CardTableModRefBS::PrecisionStyle precision, | |
388 HeapWord* boundary); | |
389 | |
390 void blk_iterate(BlkClosure* cl); | |
391 void blk_iterate_careful(BlkClosureCareful* cl); | |
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392 HeapWord* block_start_const(const void* p) const; |
0 | 393 HeapWord* block_start_careful(const void* p) const; |
394 size_t block_size(const HeapWord* p) const; | |
395 size_t block_size_no_stall(HeapWord* p, const CMSCollector* c) const; | |
396 bool block_is_obj(const HeapWord* p) const; | |
397 bool obj_is_alive(const HeapWord* p) const; | |
398 size_t block_size_nopar(const HeapWord* p) const; | |
399 bool block_is_obj_nopar(const HeapWord* p) const; | |
400 | |
401 // iteration support for promotion | |
402 void save_marks(); | |
403 bool no_allocs_since_save_marks(); | |
404 void object_iterate_since_last_GC(ObjectClosure* cl); | |
405 | |
406 // iteration support for sweeping | |
407 void save_sweep_limit() { | |
408 _sweep_limit = BlockOffsetArrayUseUnallocatedBlock ? | |
409 unallocated_block() : end(); | |
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 | |
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 | |
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481 // Support for decisions regarding concurrent collection policy |
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482 bool should_concurrent_collect() const; |
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483 |
0 | 484 // Support for compaction |
485 void prepare_for_compaction(CompactPoint* cp); | |
486 void adjust_pointers(); | |
487 void compact(); | |
488 // reset the space to reflect the fact that a compaction of the | |
489 // space has been done. | |
490 virtual void reset_after_compaction(); | |
491 | |
492 // Debugging support | |
493 void print() const; | |
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494 void print_on(outputStream* st) const; |
0 | 495 void prepare_for_verify(); |
496 void verify(bool allow_dirty) const; | |
497 void verifyFreeLists() const PRODUCT_RETURN; | |
498 void verifyIndexedFreeLists() const; | |
499 void verifyIndexedFreeList(size_t size) const; | |
500 // verify that the given chunk is in the free lists. | |
501 bool verifyChunkInFreeLists(FreeChunk* fc) const; | |
502 // Do some basic checks on the the free lists. | |
503 void checkFreeListConsistency() const PRODUCT_RETURN; | |
504 | |
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505 // Printing support |
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506 void dump_at_safepoint_with_locks(CMSCollector* c, outputStream* st); |
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507 void print_indexed_free_lists(outputStream* st) const; |
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508 void print_dictionary_free_lists(outputStream* st) const; |
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509 void print_promo_info_blocks(outputStream* st) const; |
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510 |
0 | 511 NOT_PRODUCT ( |
512 void initializeIndexedFreeListArrayReturnedBytes(); | |
513 size_t sumIndexedFreeListArrayReturnedBytes(); | |
514 // Return the total number of chunks in the indexed free lists. | |
515 size_t totalCountInIndexedFreeLists() const; | |
516 // Return the total numberof chunks in the space. | |
517 size_t totalCount(); | |
518 ) | |
519 | |
520 // The census consists of counts of the quantities such as | |
521 // the current count of the free chunks, number of chunks | |
522 // created as a result of the split of a larger chunk or | |
523 // coalescing of smaller chucks, etc. The counts in the | |
524 // census is used to make decisions on splitting and | |
525 // coalescing of chunks during the sweep of garbage. | |
526 | |
527 // Print the statistics for the free lists. | |
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528 void printFLCensus(size_t sweep_count) const; |
0 | 529 |
530 // Statistics functions | |
531 // Initialize census for lists before the sweep. | |
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532 void beginSweepFLCensus(float inter_sweep_current, |
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533 float inter_sweep_estimate, |
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534 float intra_sweep_estimate); |
0 | 535 // Set the surplus for each of the free lists. |
536 void setFLSurplus(); | |
537 // Set the hint for each of the free lists. | |
538 void setFLHints(); | |
539 // Clear the census for each of the free lists. | |
540 void clearFLCensus(); | |
541 // Perform functions for the census after the end of the sweep. | |
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542 void endSweepFLCensus(size_t sweep_count); |
0 | 543 // Return true if the count of free chunks is greater |
544 // than the desired number of free chunks. | |
545 bool coalOverPopulated(size_t size); | |
546 | |
547 // Record (for each size): | |
548 // | |
549 // split-births = #chunks added due to splits in (prev-sweep-end, | |
550 // this-sweep-start) | |
551 // split-deaths = #chunks removed for splits in (prev-sweep-end, | |
552 // this-sweep-start) | |
553 // num-curr = #chunks at start of this sweep | |
554 // num-prev = #chunks at end of previous sweep | |
555 // | |
556 // The above are quantities that are measured. Now define: | |
557 // | |
558 // num-desired := num-prev + split-births - split-deaths - num-curr | |
559 // | |
560 // Roughly, num-prev + split-births is the supply, | |
561 // split-deaths is demand due to other sizes | |
562 // and num-curr is what we have left. | |
563 // | |
564 // Thus, num-desired is roughly speaking the "legitimate demand" | |
565 // for blocks of this size and what we are striving to reach at the | |
566 // end of the current sweep. | |
567 // | |
568 // For a given list, let num-len be its current population. | |
569 // Define, for a free list of a given size: | |
570 // | |
571 // coal-overpopulated := num-len >= num-desired * coal-surplus | |
572 // (coal-surplus is set to 1.05, i.e. we allow a little slop when | |
573 // coalescing -- we do not coalesce unless we think that the current | |
574 // supply has exceeded the estimated demand by more than 5%). | |
575 // | |
576 // For the set of sizes in the binary tree, which is neither dense nor | |
577 // closed, it may be the case that for a particular size we have never | |
578 // had, or do not now have, or did not have at the previous sweep, | |
579 // chunks of that size. We need to extend the definition of | |
580 // coal-overpopulated to such sizes as well: | |
581 // | |
582 // For a chunk in/not in the binary tree, extend coal-overpopulated | |
583 // defined above to include all sizes as follows: | |
584 // | |
585 // . a size that is non-existent is coal-overpopulated | |
586 // . a size that has a num-desired <= 0 as defined above is | |
587 // coal-overpopulated. | |
588 // | |
589 // Also define, for a chunk heap-offset C and mountain heap-offset M: | |
590 // | |
591 // close-to-mountain := C >= 0.99 * M | |
592 // | |
593 // Now, the coalescing strategy is: | |
594 // | |
595 // Coalesce left-hand chunk with right-hand chunk if and | |
596 // only if: | |
597 // | |
598 // EITHER | |
599 // . left-hand chunk is of a size that is coal-overpopulated | |
600 // OR | |
601 // . right-hand chunk is close-to-mountain | |
602 void smallCoalBirth(size_t size); | |
603 void smallCoalDeath(size_t size); | |
604 void coalBirth(size_t size); | |
605 void coalDeath(size_t size); | |
606 void smallSplitBirth(size_t size); | |
607 void smallSplitDeath(size_t size); | |
608 void splitBirth(size_t size); | |
609 void splitDeath(size_t size); | |
610 void split(size_t from, size_t to1); | |
611 | |
612 double flsFrag() const; | |
613 }; | |
614 | |
615 // A parallel-GC-thread-local allocation buffer for allocation into a | |
616 // CompactibleFreeListSpace. | |
617 class CFLS_LAB : public CHeapObj { | |
618 // The space that this buffer allocates into. | |
619 CompactibleFreeListSpace* _cfls; | |
620 | |
621 // Our local free lists. | |
622 FreeList _indexedFreeList[CompactibleFreeListSpace::IndexSetSize]; | |
623 | |
624 // Initialized from a command-line arg. | |
625 | |
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626 // Allocation statistics in support of dynamic adjustment of |
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627 // #blocks to claim per get_from_global_pool() call below. |
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628 static AdaptiveWeightedAverage |
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629 _blocks_to_claim [CompactibleFreeListSpace::IndexSetSize]; |
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630 static size_t _global_num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
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631 static int _global_num_workers[CompactibleFreeListSpace::IndexSetSize]; |
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632 size_t _num_blocks [CompactibleFreeListSpace::IndexSetSize]; |
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633 |
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634 // Internal work method |
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635 void get_from_global_pool(size_t word_sz, FreeList* fl); |
0 | 636 |
637 public: | |
638 CFLS_LAB(CompactibleFreeListSpace* cfls); | |
639 | |
640 // Allocate and return a block of the given size, or else return NULL. | |
641 HeapWord* alloc(size_t word_sz); | |
642 | |
643 // Return any unused portions of the buffer to the global pool. | |
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644 void retire(int tid); |
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645 |
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646 // Dynamic OldPLABSize sizing |
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647 static void compute_desired_plab_size(); |
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648 // When the settings are modified from default static initialization |
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649 static void modify_initialization(size_t n, unsigned wt); |
0 | 650 }; |
651 | |
652 size_t PromotionInfo::refillSize() const { | |
653 const size_t CMSSpoolBlockSize = 256; | |
654 const size_t sz = heap_word_size(sizeof(SpoolBlock) + sizeof(markOop) | |
655 * CMSSpoolBlockSize); | |
656 return CompactibleFreeListSpace::adjustObjectSize(sz); | |
657 } | |
1972 | 658 |
659 #endif // SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP |