0
|
1 /*
|
|
2 * Copyright 2001-2006 Sun Microsystems, Inc. All Rights Reserved.
|
|
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 #define CFLS_LAB_REFILL_STATS 0
|
|
29
|
|
30 // Forward declarations
|
|
31 class CompactibleFreeListSpace;
|
|
32 class BlkClosure;
|
|
33 class BlkClosureCareful;
|
|
34 class UpwardsObjectClosure;
|
|
35 class ObjectClosureCareful;
|
|
36 class Klass;
|
|
37
|
|
38 class PromotedObject VALUE_OBJ_CLASS_SPEC {
|
|
39 private:
|
|
40 enum {
|
|
41 promoted_mask = right_n_bits(2), // i.e. 0x3
|
|
42 displaced_mark = nth_bit(2), // i.e. 0x4
|
|
43 next_mask = ~(right_n_bits(3)) // i.e. ~(0x7)
|
|
44 };
|
|
45 intptr_t _next;
|
|
46 public:
|
|
47 inline PromotedObject* next() const {
|
|
48 return (PromotedObject*)(_next & next_mask);
|
|
49 }
|
|
50 inline void setNext(PromotedObject* x) {
|
|
51 assert(((intptr_t)x & ~next_mask) == 0,
|
|
52 "Conflict in bit usage, "
|
|
53 " or insufficient alignment of objects");
|
|
54 _next |= (intptr_t)x;
|
|
55 }
|
|
56 inline void setPromotedMark() {
|
|
57 _next |= promoted_mask;
|
|
58 }
|
|
59 inline bool hasPromotedMark() const {
|
|
60 return (_next & promoted_mask) == promoted_mask;
|
|
61 }
|
|
62 inline void setDisplacedMark() {
|
|
63 _next |= displaced_mark;
|
|
64 }
|
|
65 inline bool hasDisplacedMark() const {
|
|
66 return (_next & displaced_mark) != 0;
|
|
67 }
|
|
68 inline void clearNext() { _next = 0; }
|
|
69 debug_only(void *next_addr() { return (void *) &_next; })
|
|
70 };
|
|
71
|
|
72 class SpoolBlock: public FreeChunk {
|
|
73 friend class PromotionInfo;
|
|
74 protected:
|
|
75 SpoolBlock* nextSpoolBlock;
|
|
76 size_t bufferSize; // number of usable words in this block
|
|
77 markOop* displacedHdr; // the displaced headers start here
|
|
78
|
|
79 // Note about bufferSize: it denotes the number of entries available plus 1;
|
|
80 // legal indices range from 1 through BufferSize - 1. See the verification
|
|
81 // code verify() that counts the number of displaced headers spooled.
|
|
82 size_t computeBufferSize() {
|
|
83 return (size() * sizeof(HeapWord) - sizeof(*this)) / sizeof(markOop);
|
|
84 }
|
|
85
|
|
86 public:
|
|
87 void init() {
|
|
88 bufferSize = computeBufferSize();
|
|
89 displacedHdr = (markOop*)&displacedHdr;
|
|
90 nextSpoolBlock = NULL;
|
|
91 }
|
|
92 };
|
|
93
|
|
94 class PromotionInfo VALUE_OBJ_CLASS_SPEC {
|
|
95 bool _tracking; // set if tracking
|
|
96 CompactibleFreeListSpace* _space; // the space to which this belongs
|
|
97 PromotedObject* _promoHead; // head of list of promoted objects
|
|
98 PromotedObject* _promoTail; // tail of list of promoted objects
|
|
99 SpoolBlock* _spoolHead; // first spooling block
|
|
100 SpoolBlock* _spoolTail; // last non-full spooling block or null
|
|
101 SpoolBlock* _splice_point; // when _spoolTail is null, holds list tail
|
|
102 SpoolBlock* _spareSpool; // free spool buffer
|
|
103 size_t _firstIndex; // first active index in
|
|
104 // first spooling block (_spoolHead)
|
|
105 size_t _nextIndex; // last active index + 1 in last
|
|
106 // spooling block (_spoolTail)
|
|
107 private:
|
|
108 // ensure that spooling space exists; return true if there is spooling space
|
|
109 bool ensure_spooling_space_work();
|
|
110
|
|
111 public:
|
|
112 PromotionInfo() :
|
|
113 _tracking(0), _space(NULL),
|
|
114 _promoHead(NULL), _promoTail(NULL),
|
|
115 _spoolHead(NULL), _spoolTail(NULL),
|
|
116 _spareSpool(NULL), _firstIndex(1),
|
|
117 _nextIndex(1) {}
|
|
118
|
|
119 bool noPromotions() const {
|
|
120 assert(_promoHead != NULL || _promoTail == NULL, "list inconsistency");
|
|
121 return _promoHead == NULL;
|
|
122 }
|
|
123 void startTrackingPromotions();
|
|
124 void stopTrackingPromotions();
|
|
125 bool tracking() const { return _tracking; }
|
|
126 void track(PromotedObject* trackOop); // keep track of a promoted oop
|
|
127 // The following variant must be used when trackOop is not fully
|
|
128 // initialized and has a NULL klass:
|
|
129 void track(PromotedObject* trackOop, klassOop klassOfOop); // keep track of a promoted oop
|
|
130 void setSpace(CompactibleFreeListSpace* sp) { _space = sp; }
|
|
131 CompactibleFreeListSpace* space() const { return _space; }
|
|
132 markOop nextDisplacedHeader(); // get next header & forward spool pointer
|
|
133 void saveDisplacedHeader(markOop hdr);
|
|
134 // save header and forward spool
|
|
135
|
|
136 inline size_t refillSize() const;
|
|
137
|
|
138 SpoolBlock* getSpoolBlock(); // return a free spooling block
|
|
139 inline bool has_spooling_space() {
|
|
140 return _spoolTail != NULL && _spoolTail->bufferSize > _nextIndex;
|
|
141 }
|
|
142 // ensure that spooling space exists
|
|
143 bool ensure_spooling_space() {
|
|
144 return has_spooling_space() || ensure_spooling_space_work();
|
|
145 }
|
|
146 #define PROMOTED_OOPS_ITERATE_DECL(OopClosureType, nv_suffix) \
|
|
147 void promoted_oops_iterate##nv_suffix(OopClosureType* cl);
|
|
148 ALL_SINCE_SAVE_MARKS_CLOSURES(PROMOTED_OOPS_ITERATE_DECL)
|
|
149 #undef PROMOTED_OOPS_ITERATE_DECL
|
|
150 void promoted_oops_iterate(OopsInGenClosure* cl) {
|
|
151 promoted_oops_iterate_v(cl);
|
|
152 }
|
|
153 void verify() const;
|
|
154 void reset() {
|
|
155 _promoHead = NULL;
|
|
156 _promoTail = NULL;
|
|
157 _spoolHead = NULL;
|
|
158 _spoolTail = NULL;
|
|
159 _spareSpool = NULL;
|
|
160 _firstIndex = 0;
|
|
161 _nextIndex = 0;
|
|
162
|
|
163 }
|
|
164 };
|
|
165
|
|
166 class LinearAllocBlock VALUE_OBJ_CLASS_SPEC {
|
|
167 public:
|
|
168 LinearAllocBlock() : _ptr(0), _word_size(0), _refillSize(0),
|
|
169 _allocation_size_limit(0) {}
|
|
170 void set(HeapWord* ptr, size_t word_size, size_t refill_size,
|
|
171 size_t allocation_size_limit) {
|
|
172 _ptr = ptr;
|
|
173 _word_size = word_size;
|
|
174 _refillSize = refill_size;
|
|
175 _allocation_size_limit = allocation_size_limit;
|
|
176 }
|
|
177 HeapWord* _ptr;
|
|
178 size_t _word_size;
|
|
179 size_t _refillSize;
|
|
180 size_t _allocation_size_limit; // largest size that will be allocated
|
|
181 };
|
|
182
|
|
183 // Concrete subclass of CompactibleSpace that implements
|
|
184 // a free list space, such as used in the concurrent mark sweep
|
|
185 // generation.
|
|
186
|
|
187 class CompactibleFreeListSpace: public CompactibleSpace {
|
|
188 friend class VMStructs;
|
|
189 friend class ConcurrentMarkSweepGeneration;
|
|
190 friend class ASConcurrentMarkSweepGeneration;
|
|
191 friend class CMSCollector;
|
|
192 friend class CMSPermGenGen;
|
|
193 // Local alloc buffer for promotion into this space.
|
|
194 friend class CFLS_LAB;
|
|
195
|
|
196 // "Size" of chunks of work (executed during parallel remark phases
|
|
197 // of CMS collection); this probably belongs in CMSCollector, although
|
|
198 // it's cached here because it's used in
|
|
199 // initialize_sequential_subtasks_for_rescan() which modifies
|
|
200 // par_seq_tasks which also lives in Space. XXX
|
|
201 const size_t _rescan_task_size;
|
|
202 const size_t _marking_task_size;
|
|
203
|
|
204 // Yet another sequential tasks done structure. This supports
|
|
205 // CMS GC, where we have threads dynamically
|
|
206 // claiming sub-tasks from a larger parallel task.
|
|
207 SequentialSubTasksDone _conc_par_seq_tasks;
|
|
208
|
|
209 BlockOffsetArrayNonContigSpace _bt;
|
|
210
|
|
211 CMSCollector* _collector;
|
|
212 ConcurrentMarkSweepGeneration* _gen;
|
|
213
|
|
214 // Data structures for free blocks (used during allocation/sweeping)
|
|
215
|
|
216 // Allocation is done linearly from two different blocks depending on
|
|
217 // whether the request is small or large, in an effort to reduce
|
|
218 // fragmentation. We assume that any locking for allocation is done
|
|
219 // by the containing generation. Thus, none of the methods in this
|
|
220 // space are re-entrant.
|
|
221 enum SomeConstants {
|
|
222 SmallForLinearAlloc = 16, // size < this then use _sLAB
|
|
223 SmallForDictionary = 257, // size < this then use _indexedFreeList
|
|
224 IndexSetSize = SmallForDictionary, // keep this odd-sized
|
|
225 IndexSetStart = MinObjAlignment,
|
|
226 IndexSetStride = MinObjAlignment
|
|
227 };
|
|
228
|
|
229 private:
|
|
230 enum FitStrategyOptions {
|
|
231 FreeBlockStrategyNone = 0,
|
|
232 FreeBlockBestFitFirst
|
|
233 };
|
|
234
|
|
235 PromotionInfo _promoInfo;
|
|
236
|
|
237 // helps to impose a global total order on freelistLock ranks;
|
|
238 // assumes that CFLSpace's are allocated in global total order
|
|
239 static int _lockRank;
|
|
240
|
|
241 // a lock protecting the free lists and free blocks;
|
|
242 // mutable because of ubiquity of locking even for otherwise const methods
|
|
243 mutable Mutex _freelistLock;
|
|
244 // locking verifier convenience function
|
|
245 void assert_locked() const PRODUCT_RETURN;
|
|
246
|
|
247 // Linear allocation blocks
|
|
248 LinearAllocBlock _smallLinearAllocBlock;
|
|
249
|
|
250 FreeBlockDictionary::DictionaryChoice _dictionaryChoice;
|
|
251 FreeBlockDictionary* _dictionary; // ptr to dictionary for large size blocks
|
|
252
|
|
253 FreeList _indexedFreeList[IndexSetSize];
|
|
254 // indexed array for small size blocks
|
|
255 // allocation stategy
|
|
256 bool _fitStrategy; // Use best fit strategy.
|
|
257 bool _adaptive_freelists; // Use adaptive freelists
|
|
258
|
|
259 // This is an address close to the largest free chunk in the heap.
|
|
260 // It is currently assumed to be at the end of the heap. Free
|
|
261 // chunks with addresses greater than nearLargestChunk are coalesced
|
|
262 // in an effort to maintain a large chunk at the end of the heap.
|
|
263 HeapWord* _nearLargestChunk;
|
|
264
|
|
265 // Used to keep track of limit of sweep for the space
|
|
266 HeapWord* _sweep_limit;
|
|
267
|
|
268 // Support for compacting cms
|
|
269 HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
|
|
270 HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top);
|
|
271
|
|
272 // Initialization helpers.
|
|
273 void initializeIndexedFreeListArray();
|
|
274
|
|
275 // Extra stuff to manage promotion parallelism.
|
|
276
|
|
277 // a lock protecting the dictionary during par promotion allocation.
|
|
278 mutable Mutex _parDictionaryAllocLock;
|
|
279 Mutex* parDictionaryAllocLock() const { return &_parDictionaryAllocLock; }
|
|
280
|
|
281 // Locks protecting the exact lists during par promotion allocation.
|
|
282 Mutex* _indexedFreeListParLocks[IndexSetSize];
|
|
283
|
|
284 #if CFLS_LAB_REFILL_STATS
|
|
285 // Some statistics.
|
|
286 jint _par_get_chunk_from_small;
|
|
287 jint _par_get_chunk_from_large;
|
|
288 #endif
|
|
289
|
|
290
|
|
291 // Attempt to obtain up to "n" blocks of the size "word_sz" (which is
|
|
292 // required to be smaller than "IndexSetSize".) If successful,
|
|
293 // adds them to "fl", which is required to be an empty free list.
|
|
294 // If the count of "fl" is negative, it's absolute value indicates a
|
|
295 // number of free chunks that had been previously "borrowed" from global
|
|
296 // list of size "word_sz", and must now be decremented.
|
|
297 void par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl);
|
|
298
|
|
299 // Allocation helper functions
|
|
300 // Allocate using a strategy that takes from the indexed free lists
|
|
301 // first. This allocation strategy assumes a companion sweeping
|
|
302 // strategy that attempts to keep the needed number of chunks in each
|
|
303 // indexed free lists.
|
|
304 HeapWord* allocate_adaptive_freelists(size_t size);
|
|
305 // Allocate from the linear allocation buffers first. This allocation
|
|
306 // strategy assumes maximal coalescing can maintain chunks large enough
|
|
307 // to be used as linear allocation buffers.
|
|
308 HeapWord* allocate_non_adaptive_freelists(size_t size);
|
|
309
|
|
310 // Gets a chunk from the linear allocation block (LinAB). If there
|
|
311 // is not enough space in the LinAB, refills it.
|
|
312 HeapWord* getChunkFromLinearAllocBlock(LinearAllocBlock* blk, size_t size);
|
|
313 HeapWord* getChunkFromSmallLinearAllocBlock(size_t size);
|
|
314 // Get a chunk from the space remaining in the linear allocation block. Do
|
|
315 // not attempt to refill if the space is not available, return NULL. Do the
|
|
316 // repairs on the linear allocation block as appropriate.
|
|
317 HeapWord* getChunkFromLinearAllocBlockRemainder(LinearAllocBlock* blk, size_t size);
|
|
318 inline HeapWord* getChunkFromSmallLinearAllocBlockRemainder(size_t size);
|
|
319
|
|
320 // Helper function for getChunkFromIndexedFreeList.
|
|
321 // Replenish the indexed free list for this "size". Do not take from an
|
|
322 // underpopulated size.
|
|
323 FreeChunk* getChunkFromIndexedFreeListHelper(size_t size);
|
|
324
|
|
325 // Get a chunk from the indexed free list. If the indexed free list
|
|
326 // does not have a free chunk, try to replenish the indexed free list
|
|
327 // then get the free chunk from the replenished indexed free list.
|
|
328 inline FreeChunk* getChunkFromIndexedFreeList(size_t size);
|
|
329
|
|
330 // The returned chunk may be larger than requested (or null).
|
|
331 FreeChunk* getChunkFromDictionary(size_t size);
|
|
332 // The returned chunk is the exact size requested (or null).
|
|
333 FreeChunk* getChunkFromDictionaryExact(size_t size);
|
|
334
|
|
335 // Find a chunk in the indexed free list that is the best
|
|
336 // fit for size "numWords".
|
|
337 FreeChunk* bestFitSmall(size_t numWords);
|
|
338 // For free list "fl" of chunks of size > numWords,
|
|
339 // remove a chunk, split off a chunk of size numWords
|
|
340 // and return it. The split off remainder is returned to
|
|
341 // the free lists. The old name for getFromListGreater
|
|
342 // was lookInListGreater.
|
|
343 FreeChunk* getFromListGreater(FreeList* fl, size_t numWords);
|
|
344 // Get a chunk in the indexed free list or dictionary,
|
|
345 // by considering a larger chunk and splitting it.
|
|
346 FreeChunk* getChunkFromGreater(size_t numWords);
|
|
347 // Verify that the given chunk is in the indexed free lists.
|
|
348 bool verifyChunkInIndexedFreeLists(FreeChunk* fc) const;
|
|
349 // Remove the specified chunk from the indexed free lists.
|
|
350 void removeChunkFromIndexedFreeList(FreeChunk* fc);
|
|
351 // Remove the specified chunk from the dictionary.
|
|
352 void removeChunkFromDictionary(FreeChunk* fc);
|
|
353 // Split a free chunk into a smaller free chunk of size "new_size".
|
|
354 // Return the smaller free chunk and return the remainder to the
|
|
355 // free lists.
|
|
356 FreeChunk* splitChunkAndReturnRemainder(FreeChunk* chunk, size_t new_size);
|
|
357 // Add a chunk to the free lists.
|
|
358 void addChunkToFreeLists(HeapWord* chunk, size_t size);
|
|
359 // Add a chunk to the free lists, preferring to suffix it
|
|
360 // to the last free chunk at end of space if possible, and
|
|
361 // updating the block census stats as well as block offset table.
|
|
362 // Take any locks as appropriate if we are multithreaded.
|
|
363 void addChunkToFreeListsAtEndRecordingStats(HeapWord* chunk, size_t size);
|
|
364 // Add a free chunk to the indexed free lists.
|
|
365 void returnChunkToFreeList(FreeChunk* chunk);
|
|
366 // Add a free chunk to the dictionary.
|
|
367 void returnChunkToDictionary(FreeChunk* chunk);
|
|
368
|
|
369 // Functions for maintaining the linear allocation buffers (LinAB).
|
|
370 // Repairing a linear allocation block refers to operations
|
|
371 // performed on the remainder of a LinAB after an allocation
|
|
372 // has been made from it.
|
|
373 void repairLinearAllocationBlocks();
|
|
374 void repairLinearAllocBlock(LinearAllocBlock* blk);
|
|
375 void refillLinearAllocBlock(LinearAllocBlock* blk);
|
|
376 void refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk);
|
|
377 void refillLinearAllocBlocksIfNeeded();
|
|
378
|
|
379 void verify_objects_initialized() const;
|
|
380
|
|
381 // Statistics reporting helper functions
|
|
382 void reportFreeListStatistics() const;
|
|
383 void reportIndexedFreeListStatistics() const;
|
|
384 size_t maxChunkSizeInIndexedFreeLists() const;
|
|
385 size_t numFreeBlocksInIndexedFreeLists() const;
|
|
386 // Accessor
|
|
387 HeapWord* unallocated_block() const {
|
|
388 HeapWord* ub = _bt.unallocated_block();
|
|
389 assert(ub >= bottom() &&
|
|
390 ub <= end(), "space invariant");
|
|
391 return ub;
|
|
392 }
|
|
393 void freed(HeapWord* start, size_t size) {
|
|
394 _bt.freed(start, size);
|
|
395 }
|
|
396
|
|
397 protected:
|
|
398 // reset the indexed free list to its initial empty condition.
|
|
399 void resetIndexedFreeListArray();
|
|
400 // reset to an initial state with a single free block described
|
|
401 // by the MemRegion parameter.
|
|
402 void reset(MemRegion mr);
|
|
403 // Return the total number of words in the indexed free lists.
|
|
404 size_t totalSizeInIndexedFreeLists() const;
|
|
405
|
|
406 public:
|
|
407 // Constructor...
|
|
408 CompactibleFreeListSpace(BlockOffsetSharedArray* bs, MemRegion mr,
|
|
409 bool use_adaptive_freelists,
|
|
410 FreeBlockDictionary::DictionaryChoice);
|
|
411 // accessors
|
|
412 bool bestFitFirst() { return _fitStrategy == FreeBlockBestFitFirst; }
|
|
413 FreeBlockDictionary* dictionary() const { return _dictionary; }
|
|
414 HeapWord* nearLargestChunk() const { return _nearLargestChunk; }
|
|
415 void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; }
|
|
416
|
|
417 // Return the free chunk at the end of the space. If no such
|
|
418 // chunk exists, return NULL.
|
|
419 FreeChunk* find_chunk_at_end();
|
|
420
|
|
421 bool adaptive_freelists() { return _adaptive_freelists; }
|
|
422
|
|
423 void set_collector(CMSCollector* collector) { _collector = collector; }
|
|
424
|
|
425 // Support for parallelization of rescan and marking
|
|
426 const size_t rescan_task_size() const { return _rescan_task_size; }
|
|
427 const size_t marking_task_size() const { return _marking_task_size; }
|
|
428 SequentialSubTasksDone* conc_par_seq_tasks() {return &_conc_par_seq_tasks; }
|
|
429 void initialize_sequential_subtasks_for_rescan(int n_threads);
|
|
430 void initialize_sequential_subtasks_for_marking(int n_threads,
|
|
431 HeapWord* low = NULL);
|
|
432
|
|
433 #if CFLS_LAB_REFILL_STATS
|
|
434 void print_par_alloc_stats();
|
|
435 #endif
|
|
436
|
|
437 // Space enquiries
|
|
438 size_t used() const;
|
|
439 size_t free() const;
|
|
440 size_t max_alloc_in_words() const;
|
|
441 // XXX: should have a less conservative used_region() than that of
|
|
442 // Space; we could consider keeping track of highest allocated
|
|
443 // address and correcting that at each sweep, as the sweeper
|
|
444 // goes through the entire allocated part of the generation. We
|
|
445 // could also use that information to keep the sweeper from
|
|
446 // sweeping more than is necessary. The allocator and sweeper will
|
|
447 // of course need to synchronize on this, since the sweeper will
|
|
448 // try to bump down the address and the allocator will try to bump it up.
|
|
449 // For now, however, we'll just use the default used_region()
|
|
450 // which overestimates the region by returning the entire
|
|
451 // committed region (this is safe, but inefficient).
|
|
452
|
|
453 // Returns a subregion of the space containing all the objects in
|
|
454 // the space.
|
|
455 MemRegion used_region() const {
|
|
456 return MemRegion(bottom(),
|
|
457 BlockOffsetArrayUseUnallocatedBlock ?
|
|
458 unallocated_block() : end());
|
|
459 }
|
|
460
|
|
461 // This is needed because the default implementation uses block_start()
|
|
462 // which can;t be used at certain times (for example phase 3 of mark-sweep).
|
|
463 // A better fix is to change the assertions in phase 3 of mark-sweep to
|
|
464 // use is_in_reserved(), but that is deferred since the is_in() assertions
|
|
465 // are buried through several layers of callers and are used elsewhere
|
|
466 // as well.
|
|
467 bool is_in(const void* p) const {
|
|
468 return used_region().contains(p);
|
|
469 }
|
|
470
|
|
471 virtual bool is_free_block(const HeapWord* p) const;
|
|
472
|
|
473 // Resizing support
|
|
474 void set_end(HeapWord* value); // override
|
|
475
|
|
476 // mutual exclusion support
|
|
477 Mutex* freelistLock() const { return &_freelistLock; }
|
|
478
|
|
479 // Iteration support
|
|
480 void oop_iterate(MemRegion mr, OopClosure* cl);
|
|
481 void oop_iterate(OopClosure* cl);
|
|
482
|
|
483 void object_iterate(ObjectClosure* blk);
|
|
484 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
|
|
485
|
|
486 // Requires that "mr" be entirely within the space.
|
|
487 // Apply "cl->do_object" to all objects that intersect with "mr".
|
|
488 // If the iteration encounters an unparseable portion of the region,
|
|
489 // terminate the iteration and return the address of the start of the
|
|
490 // subregion that isn't done. Return of "NULL" indicates that the
|
|
491 // interation completed.
|
|
492 virtual HeapWord*
|
|
493 object_iterate_careful_m(MemRegion mr,
|
|
494 ObjectClosureCareful* cl);
|
|
495 virtual HeapWord*
|
|
496 object_iterate_careful(ObjectClosureCareful* cl);
|
|
497
|
|
498 // Override: provides a DCTO_CL specific to this kind of space.
|
|
499 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl,
|
|
500 CardTableModRefBS::PrecisionStyle precision,
|
|
501 HeapWord* boundary);
|
|
502
|
|
503 void blk_iterate(BlkClosure* cl);
|
|
504 void blk_iterate_careful(BlkClosureCareful* cl);
|
|
505 HeapWord* block_start(const void* p) const;
|
|
506 HeapWord* block_start_careful(const void* p) const;
|
|
507 size_t block_size(const HeapWord* p) const;
|
|
508 size_t block_size_no_stall(HeapWord* p, const CMSCollector* c) const;
|
|
509 bool block_is_obj(const HeapWord* p) const;
|
|
510 bool obj_is_alive(const HeapWord* p) const;
|
|
511 size_t block_size_nopar(const HeapWord* p) const;
|
|
512 bool block_is_obj_nopar(const HeapWord* p) const;
|
|
513
|
|
514 // iteration support for promotion
|
|
515 void save_marks();
|
|
516 bool no_allocs_since_save_marks();
|
|
517 void object_iterate_since_last_GC(ObjectClosure* cl);
|
|
518
|
|
519 // iteration support for sweeping
|
|
520 void save_sweep_limit() {
|
|
521 _sweep_limit = BlockOffsetArrayUseUnallocatedBlock ?
|
|
522 unallocated_block() : end();
|
|
523 }
|
|
524 NOT_PRODUCT(
|
|
525 void clear_sweep_limit() { _sweep_limit = NULL; }
|
|
526 )
|
|
527 HeapWord* sweep_limit() { return _sweep_limit; }
|
|
528
|
|
529 // Apply "blk->do_oop" to the addresses of all reference fields in objects
|
|
530 // promoted into this generation since the most recent save_marks() call.
|
|
531 // Fields in objects allocated by applications of the closure
|
|
532 // *are* included in the iteration. Thus, when the iteration completes
|
|
533 // there should be no further such objects remaining.
|
|
534 #define CFLS_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
|
|
535 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk);
|
|
536 ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DECL)
|
|
537 #undef CFLS_OOP_SINCE_SAVE_MARKS_DECL
|
|
538
|
|
539 // Allocation support
|
|
540 HeapWord* allocate(size_t size);
|
|
541 HeapWord* par_allocate(size_t size);
|
|
542
|
|
543 oop promote(oop obj, size_t obj_size, oop* ref);
|
|
544 void gc_prologue();
|
|
545 void gc_epilogue();
|
|
546
|
|
547 // This call is used by a containing CMS generation / collector
|
|
548 // to inform the CFLS space that a sweep has been completed
|
|
549 // and that the space can do any related house-keeping functions.
|
|
550 void sweep_completed();
|
|
551
|
|
552 // For an object in this space, the mark-word's two
|
|
553 // LSB's having the value [11] indicates that it has been
|
|
554 // promoted since the most recent call to save_marks() on
|
|
555 // this generation and has not subsequently been iterated
|
|
556 // over (using oop_since_save_marks_iterate() above).
|
|
557 bool obj_allocated_since_save_marks(const oop obj) const {
|
|
558 assert(is_in_reserved(obj), "Wrong space?");
|
|
559 return ((PromotedObject*)obj)->hasPromotedMark();
|
|
560 }
|
|
561
|
|
562 // A worst-case estimate of the space required (in HeapWords) to expand the
|
|
563 // heap when promoting an obj of size obj_size.
|
|
564 size_t expansionSpaceRequired(size_t obj_size) const;
|
|
565
|
|
566 FreeChunk* allocateScratch(size_t size);
|
|
567
|
|
568 // returns true if either the small or large linear allocation buffer is empty.
|
|
569 bool linearAllocationWouldFail();
|
|
570
|
|
571 // Adjust the chunk for the minimum size. This version is called in
|
|
572 // most cases in CompactibleFreeListSpace methods.
|
|
573 inline static size_t adjustObjectSize(size_t size) {
|
|
574 return (size_t) align_object_size(MAX2(size, (size_t)MinChunkSize));
|
|
575 }
|
|
576 // This is a virtual version of adjustObjectSize() that is called
|
|
577 // only occasionally when the compaction space changes and the type
|
|
578 // of the new compaction space is is only known to be CompactibleSpace.
|
|
579 size_t adjust_object_size_v(size_t size) const {
|
|
580 return adjustObjectSize(size);
|
|
581 }
|
|
582 // Minimum size of a free block.
|
|
583 virtual size_t minimum_free_block_size() const { return MinChunkSize; }
|
|
584 void removeFreeChunkFromFreeLists(FreeChunk* chunk);
|
|
585 void addChunkAndRepairOffsetTable(HeapWord* chunk, size_t size,
|
|
586 bool coalesced);
|
|
587
|
|
588 // Support for compaction
|
|
589 void prepare_for_compaction(CompactPoint* cp);
|
|
590 void adjust_pointers();
|
|
591 void compact();
|
|
592 // reset the space to reflect the fact that a compaction of the
|
|
593 // space has been done.
|
|
594 virtual void reset_after_compaction();
|
|
595
|
|
596 // Debugging support
|
|
597 void print() const;
|
|
598 void prepare_for_verify();
|
|
599 void verify(bool allow_dirty) const;
|
|
600 void verifyFreeLists() const PRODUCT_RETURN;
|
|
601 void verifyIndexedFreeLists() const;
|
|
602 void verifyIndexedFreeList(size_t size) const;
|
|
603 // verify that the given chunk is in the free lists.
|
|
604 bool verifyChunkInFreeLists(FreeChunk* fc) const;
|
|
605 // Do some basic checks on the the free lists.
|
|
606 void checkFreeListConsistency() const PRODUCT_RETURN;
|
|
607
|
|
608 NOT_PRODUCT (
|
|
609 void initializeIndexedFreeListArrayReturnedBytes();
|
|
610 size_t sumIndexedFreeListArrayReturnedBytes();
|
|
611 // Return the total number of chunks in the indexed free lists.
|
|
612 size_t totalCountInIndexedFreeLists() const;
|
|
613 // Return the total numberof chunks in the space.
|
|
614 size_t totalCount();
|
|
615 )
|
|
616
|
|
617 // The census consists of counts of the quantities such as
|
|
618 // the current count of the free chunks, number of chunks
|
|
619 // created as a result of the split of a larger chunk or
|
|
620 // coalescing of smaller chucks, etc. The counts in the
|
|
621 // census is used to make decisions on splitting and
|
|
622 // coalescing of chunks during the sweep of garbage.
|
|
623
|
|
624 // Print the statistics for the free lists.
|
|
625 void printFLCensus(int sweepCt) const;
|
|
626
|
|
627 // Statistics functions
|
|
628 // Initialize census for lists before the sweep.
|
|
629 void beginSweepFLCensus(float sweep_current,
|
|
630 float sweep_estimate);
|
|
631 // Set the surplus for each of the free lists.
|
|
632 void setFLSurplus();
|
|
633 // Set the hint for each of the free lists.
|
|
634 void setFLHints();
|
|
635 // Clear the census for each of the free lists.
|
|
636 void clearFLCensus();
|
|
637 // Perform functions for the census after the end of the sweep.
|
|
638 void endSweepFLCensus(int sweepCt);
|
|
639 // Return true if the count of free chunks is greater
|
|
640 // than the desired number of free chunks.
|
|
641 bool coalOverPopulated(size_t size);
|
|
642
|
|
643
|
|
644 // Record (for each size):
|
|
645 //
|
|
646 // split-births = #chunks added due to splits in (prev-sweep-end,
|
|
647 // this-sweep-start)
|
|
648 // split-deaths = #chunks removed for splits in (prev-sweep-end,
|
|
649 // this-sweep-start)
|
|
650 // num-curr = #chunks at start of this sweep
|
|
651 // num-prev = #chunks at end of previous sweep
|
|
652 //
|
|
653 // The above are quantities that are measured. Now define:
|
|
654 //
|
|
655 // num-desired := num-prev + split-births - split-deaths - num-curr
|
|
656 //
|
|
657 // Roughly, num-prev + split-births is the supply,
|
|
658 // split-deaths is demand due to other sizes
|
|
659 // and num-curr is what we have left.
|
|
660 //
|
|
661 // Thus, num-desired is roughly speaking the "legitimate demand"
|
|
662 // for blocks of this size and what we are striving to reach at the
|
|
663 // end of the current sweep.
|
|
664 //
|
|
665 // For a given list, let num-len be its current population.
|
|
666 // Define, for a free list of a given size:
|
|
667 //
|
|
668 // coal-overpopulated := num-len >= num-desired * coal-surplus
|
|
669 // (coal-surplus is set to 1.05, i.e. we allow a little slop when
|
|
670 // coalescing -- we do not coalesce unless we think that the current
|
|
671 // supply has exceeded the estimated demand by more than 5%).
|
|
672 //
|
|
673 // For the set of sizes in the binary tree, which is neither dense nor
|
|
674 // closed, it may be the case that for a particular size we have never
|
|
675 // had, or do not now have, or did not have at the previous sweep,
|
|
676 // chunks of that size. We need to extend the definition of
|
|
677 // coal-overpopulated to such sizes as well:
|
|
678 //
|
|
679 // For a chunk in/not in the binary tree, extend coal-overpopulated
|
|
680 // defined above to include all sizes as follows:
|
|
681 //
|
|
682 // . a size that is non-existent is coal-overpopulated
|
|
683 // . a size that has a num-desired <= 0 as defined above is
|
|
684 // coal-overpopulated.
|
|
685 //
|
|
686 // Also define, for a chunk heap-offset C and mountain heap-offset M:
|
|
687 //
|
|
688 // close-to-mountain := C >= 0.99 * M
|
|
689 //
|
|
690 // Now, the coalescing strategy is:
|
|
691 //
|
|
692 // Coalesce left-hand chunk with right-hand chunk if and
|
|
693 // only if:
|
|
694 //
|
|
695 // EITHER
|
|
696 // . left-hand chunk is of a size that is coal-overpopulated
|
|
697 // OR
|
|
698 // . right-hand chunk is close-to-mountain
|
|
699 void smallCoalBirth(size_t size);
|
|
700 void smallCoalDeath(size_t size);
|
|
701 void coalBirth(size_t size);
|
|
702 void coalDeath(size_t size);
|
|
703 void smallSplitBirth(size_t size);
|
|
704 void smallSplitDeath(size_t size);
|
|
705 void splitBirth(size_t size);
|
|
706 void splitDeath(size_t size);
|
|
707 void split(size_t from, size_t to1);
|
|
708
|
|
709 double flsFrag() const;
|
|
710 };
|
|
711
|
|
712 // A parallel-GC-thread-local allocation buffer for allocation into a
|
|
713 // CompactibleFreeListSpace.
|
|
714 class CFLS_LAB : public CHeapObj {
|
|
715 // The space that this buffer allocates into.
|
|
716 CompactibleFreeListSpace* _cfls;
|
|
717
|
|
718 // Our local free lists.
|
|
719 FreeList _indexedFreeList[CompactibleFreeListSpace::IndexSetSize];
|
|
720
|
|
721 // Initialized from a command-line arg.
|
|
722 size_t _blocks_to_claim;
|
|
723
|
|
724 #if CFLS_LAB_REFILL_STATS
|
|
725 // Some statistics.
|
|
726 int _refills;
|
|
727 int _blocksTaken;
|
|
728 static int _tot_refills;
|
|
729 static int _tot_blocksTaken;
|
|
730 static int _next_threshold;
|
|
731 #endif
|
|
732
|
|
733 public:
|
|
734 CFLS_LAB(CompactibleFreeListSpace* cfls);
|
|
735
|
|
736 // Allocate and return a block of the given size, or else return NULL.
|
|
737 HeapWord* alloc(size_t word_sz);
|
|
738
|
|
739 // Return any unused portions of the buffer to the global pool.
|
|
740 void retire();
|
|
741 };
|
|
742
|
|
743 size_t PromotionInfo::refillSize() const {
|
|
744 const size_t CMSSpoolBlockSize = 256;
|
|
745 const size_t sz = heap_word_size(sizeof(SpoolBlock) + sizeof(markOop)
|
|
746 * CMSSpoolBlockSize);
|
|
747 return CompactibleFreeListSpace::adjustObjectSize(sz);
|
|
748 }
|