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comparison src/share/vm/gc_implementation/parNew/parNewGeneration.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | ba764ed4b6f2 |
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1 /* | |
2 * Copyright 2001-2007 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 class ChunkArray; | |
26 class ParScanWithoutBarrierClosure; | |
27 class ParScanWithBarrierClosure; | |
28 class ParRootScanWithoutBarrierClosure; | |
29 class ParRootScanWithBarrierTwoGensClosure; | |
30 class ParEvacuateFollowersClosure; | |
31 | |
32 // It would be better if these types could be kept local to the .cpp file, | |
33 // but they must be here to allow ParScanClosure::do_oop_work to be defined | |
34 // in genOopClosures.inline.hpp. | |
35 | |
36 | |
37 typedef OopTaskQueue ObjToScanQueue; | |
38 typedef OopTaskQueueSet ObjToScanQueueSet; | |
39 | |
40 // Enable this to get push/pop/steal stats. | |
41 const int PAR_STATS_ENABLED = 0; | |
42 | |
43 class ParKeepAliveClosure: public DefNewGeneration::KeepAliveClosure { | |
44 ParScanWeakRefClosure* _par_cl; | |
45 public: | |
46 ParKeepAliveClosure(ParScanWeakRefClosure* cl); | |
47 void do_oop(oop* p); | |
48 }; | |
49 | |
50 // The state needed by thread performing parallel young-gen collection. | |
51 class ParScanThreadState { | |
52 friend class ParScanThreadStateSet; | |
53 ObjToScanQueue *_work_queue; | |
54 | |
55 ParGCAllocBuffer _to_space_alloc_buffer; | |
56 | |
57 ParScanWithoutBarrierClosure _to_space_closure; // scan_without_gc_barrier | |
58 ParScanWithBarrierClosure _old_gen_closure; // scan_with_gc_barrier | |
59 ParRootScanWithoutBarrierClosure _to_space_root_closure; // scan_root_without_gc_barrier | |
60 // One of these two will be passed to process_strong_roots, which will | |
61 // set its generation. The first is for two-gen configs where the | |
62 // old gen collects the perm gen; the second is for arbitrary configs. | |
63 // The second isn't used right now (it used to be used for the train, an | |
64 // incremental collector) but the declaration has been left as a reminder. | |
65 ParRootScanWithBarrierTwoGensClosure _older_gen_closure; | |
66 // This closure will always be bound to the old gen; it will be used | |
67 // in evacuate_followers. | |
68 ParRootScanWithBarrierTwoGensClosure _old_gen_root_closure; // scan_old_root_with_gc_barrier | |
69 ParEvacuateFollowersClosure _evacuate_followers; | |
70 DefNewGeneration::IsAliveClosure _is_alive_closure; | |
71 ParScanWeakRefClosure _scan_weak_ref_closure; | |
72 ParKeepAliveClosure _keep_alive_closure; | |
73 | |
74 | |
75 Space* _to_space; | |
76 Space* to_space() { return _to_space; } | |
77 | |
78 Generation* _old_gen; | |
79 Generation* old_gen() { return _old_gen; } | |
80 | |
81 HeapWord *_young_old_boundary; | |
82 | |
83 int _hash_seed; | |
84 int _thread_num; | |
85 ageTable _ageTable; | |
86 | |
87 bool _to_space_full; | |
88 | |
89 int _pushes, _pops, _steals, _steal_attempts, _term_attempts; | |
90 int _overflow_pushes, _overflow_refills, _overflow_refill_objs; | |
91 | |
92 // Timing numbers. | |
93 double _start; | |
94 double _start_strong_roots; | |
95 double _strong_roots_time; | |
96 double _start_term; | |
97 double _term_time; | |
98 | |
99 // Helper for trim_queues. Scans subset of an array and makes | |
100 // remainder available for work stealing. | |
101 void scan_partial_array_and_push_remainder(oop obj); | |
102 | |
103 // In support of CMS' parallel rescan of survivor space. | |
104 ChunkArray* _survivor_chunk_array; | |
105 ChunkArray* survivor_chunk_array() { return _survivor_chunk_array; } | |
106 | |
107 void record_survivor_plab(HeapWord* plab_start, size_t plab_word_size); | |
108 | |
109 ParScanThreadState(Space* to_space_, ParNewGeneration* gen_, | |
110 Generation* old_gen_, int thread_num_, | |
111 ObjToScanQueueSet* work_queue_set_, size_t desired_plab_sz_, | |
112 ParallelTaskTerminator& term_); | |
113 | |
114 public: | |
115 ageTable* age_table() {return &_ageTable;} | |
116 | |
117 ObjToScanQueue* work_queue() { return _work_queue; } | |
118 | |
119 ParGCAllocBuffer* to_space_alloc_buffer() { | |
120 return &_to_space_alloc_buffer; | |
121 } | |
122 | |
123 ParEvacuateFollowersClosure& evacuate_followers_closure() { return _evacuate_followers; } | |
124 DefNewGeneration::IsAliveClosure& is_alive_closure() { return _is_alive_closure; } | |
125 ParScanWeakRefClosure& scan_weak_ref_closure() { return _scan_weak_ref_closure; } | |
126 ParKeepAliveClosure& keep_alive_closure() { return _keep_alive_closure; } | |
127 ParScanClosure& older_gen_closure() { return _older_gen_closure; } | |
128 ParRootScanWithoutBarrierClosure& to_space_root_closure() { return _to_space_root_closure; }; | |
129 | |
130 // Decrease queue size below "max_size". | |
131 void trim_queues(int max_size); | |
132 | |
133 // Is new_obj a candidate for scan_partial_array_and_push_remainder method. | |
134 inline bool should_be_partially_scanned(oop new_obj, oop old_obj) const; | |
135 | |
136 int* hash_seed() { return &_hash_seed; } | |
137 int thread_num() { return _thread_num; } | |
138 | |
139 // Allocate a to-space block of size "sz", or else return NULL. | |
140 HeapWord* alloc_in_to_space_slow(size_t word_sz); | |
141 | |
142 HeapWord* alloc_in_to_space(size_t word_sz) { | |
143 HeapWord* obj = to_space_alloc_buffer()->allocate(word_sz); | |
144 if (obj != NULL) return obj; | |
145 else return alloc_in_to_space_slow(word_sz); | |
146 } | |
147 | |
148 HeapWord* young_old_boundary() { return _young_old_boundary; } | |
149 | |
150 void set_young_old_boundary(HeapWord *boundary) { | |
151 _young_old_boundary = boundary; | |
152 } | |
153 | |
154 // Undo the most recent allocation ("obj", of "word_sz"). | |
155 void undo_alloc_in_to_space(HeapWord* obj, size_t word_sz); | |
156 | |
157 int pushes() { return _pushes; } | |
158 int pops() { return _pops; } | |
159 int steals() { return _steals; } | |
160 int steal_attempts() { return _steal_attempts; } | |
161 int term_attempts() { return _term_attempts; } | |
162 int overflow_pushes() { return _overflow_pushes; } | |
163 int overflow_refills() { return _overflow_refills; } | |
164 int overflow_refill_objs() { return _overflow_refill_objs; } | |
165 | |
166 void note_push() { if (PAR_STATS_ENABLED) _pushes++; } | |
167 void note_pop() { if (PAR_STATS_ENABLED) _pops++; } | |
168 void note_steal() { if (PAR_STATS_ENABLED) _steals++; } | |
169 void note_steal_attempt() { if (PAR_STATS_ENABLED) _steal_attempts++; } | |
170 void note_term_attempt() { if (PAR_STATS_ENABLED) _term_attempts++; } | |
171 void note_overflow_push() { if (PAR_STATS_ENABLED) _overflow_pushes++; } | |
172 void note_overflow_refill(int objs) { | |
173 if (PAR_STATS_ENABLED) { | |
174 _overflow_refills++; | |
175 _overflow_refill_objs += objs; | |
176 } | |
177 } | |
178 | |
179 void start_strong_roots() { | |
180 _start_strong_roots = os::elapsedTime(); | |
181 } | |
182 void end_strong_roots() { | |
183 _strong_roots_time += (os::elapsedTime() - _start_strong_roots); | |
184 } | |
185 double strong_roots_time() { return _strong_roots_time; } | |
186 void start_term_time() { | |
187 note_term_attempt(); | |
188 _start_term = os::elapsedTime(); | |
189 } | |
190 void end_term_time() { | |
191 _term_time += (os::elapsedTime() - _start_term); | |
192 } | |
193 double term_time() { return _term_time; } | |
194 | |
195 double elapsed() { | |
196 return os::elapsedTime() - _start; | |
197 } | |
198 | |
199 }; | |
200 | |
201 class ParNewGenTask: public AbstractGangTask { | |
202 ParNewGeneration* _gen; | |
203 Generation* _next_gen; | |
204 HeapWord* _young_old_boundary; | |
205 class ParScanThreadStateSet* _state_set; | |
206 | |
207 public: | |
208 ParNewGenTask(ParNewGeneration* gen, | |
209 Generation* next_gen, | |
210 HeapWord* young_old_boundary, | |
211 ParScanThreadStateSet* state_set); | |
212 | |
213 HeapWord* young_old_boundary() { return _young_old_boundary; } | |
214 | |
215 void work(int i); | |
216 }; | |
217 | |
218 class KeepAliveClosure: public DefNewGeneration::KeepAliveClosure { | |
219 public: | |
220 KeepAliveClosure(ScanWeakRefClosure* cl); | |
221 void do_oop(oop* p); | |
222 }; | |
223 | |
224 class EvacuateFollowersClosureGeneral: public VoidClosure { | |
225 GenCollectedHeap* _gch; | |
226 int _level; | |
227 OopsInGenClosure* _scan_cur_or_nonheap; | |
228 OopsInGenClosure* _scan_older; | |
229 public: | |
230 EvacuateFollowersClosureGeneral(GenCollectedHeap* gch, int level, | |
231 OopsInGenClosure* cur, | |
232 OopsInGenClosure* older); | |
233 void do_void(); | |
234 }; | |
235 | |
236 // Closure for scanning ParNewGeneration. | |
237 // Same as ScanClosure, except does parallel GC barrier. | |
238 class ScanClosureWithParBarrier: public ScanClosure { | |
239 public: | |
240 ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier); | |
241 void do_oop(oop* p); | |
242 }; | |
243 | |
244 // Implements AbstractRefProcTaskExecutor for ParNew. | |
245 class ParNewRefProcTaskExecutor: public AbstractRefProcTaskExecutor { | |
246 public: | |
247 | |
248 ParNewRefProcTaskExecutor(ParNewGeneration& generation, | |
249 ParScanThreadStateSet& state_set) | |
250 : _generation(generation), _state_set(state_set) | |
251 { } | |
252 | |
253 // Executes a task using worker threads. | |
254 virtual void execute(ProcessTask& task); | |
255 virtual void execute(EnqueueTask& task); | |
256 // Switch to single threaded mode. | |
257 virtual void set_single_threaded_mode(); | |
258 private: | |
259 ParNewGeneration& _generation; | |
260 ParScanThreadStateSet& _state_set; | |
261 }; | |
262 | |
263 | |
264 // A Generation that does parallel young-gen collection. | |
265 | |
266 class ParNewGeneration: public DefNewGeneration { | |
267 friend class ParNewGenTask; | |
268 friend class ParNewRefProcTask; | |
269 friend class ParNewRefProcTaskExecutor; | |
270 friend class ParScanThreadStateSet; | |
271 | |
272 // XXX use a global constant instead of 64! | |
273 struct ObjToScanQueuePadded { | |
274 ObjToScanQueue work_queue; | |
275 char pad[64 - sizeof(ObjToScanQueue)]; // prevent false sharing | |
276 }; | |
277 | |
278 // The per-thread work queues, available here for stealing. | |
279 ObjToScanQueueSet* _task_queues; | |
280 | |
281 // Desired size of survivor space plab's | |
282 PLABStats _plab_stats; | |
283 | |
284 // A list of from-space images of to-be-scanned objects, threaded through | |
285 // klass-pointers (klass information already copied to the forwarded | |
286 // image.) Manipulated with CAS. | |
287 oop _overflow_list; | |
288 | |
289 // If true, older generation does not support promotion undo, so avoid. | |
290 static bool _avoid_promotion_undo; | |
291 | |
292 // This closure is used by the reference processor to filter out | |
293 // references to live referent. | |
294 DefNewGeneration::IsAliveClosure _is_alive_closure; | |
295 | |
296 static oop real_forwardee_slow(oop obj); | |
297 static void waste_some_time(); | |
298 | |
299 // Preserve the mark of "obj", if necessary, in preparation for its mark | |
300 // word being overwritten with a self-forwarding-pointer. | |
301 void preserve_mark_if_necessary(oop obj, markOop m); | |
302 | |
303 protected: | |
304 | |
305 bool _survivor_overflow; | |
306 | |
307 bool avoid_promotion_undo() { return _avoid_promotion_undo; } | |
308 void set_avoid_promotion_undo(bool v) { _avoid_promotion_undo = v; } | |
309 | |
310 bool survivor_overflow() { return _survivor_overflow; } | |
311 void set_survivor_overflow(bool v) { _survivor_overflow = v; } | |
312 | |
313 // Adjust the tenuring threshold. See the implementation for | |
314 // the details of the policy. | |
315 virtual void adjust_desired_tenuring_threshold(); | |
316 | |
317 public: | |
318 ParNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level); | |
319 | |
320 ~ParNewGeneration() { | |
321 for (uint i = 0; i < ParallelGCThreads; i++) | |
322 delete _task_queues->queue(i); | |
323 | |
324 delete _task_queues; | |
325 } | |
326 | |
327 virtual void ref_processor_init(); | |
328 virtual Generation::Name kind() { return Generation::ParNew; } | |
329 virtual const char* name() const; | |
330 virtual const char* short_name() const { return "ParNew"; } | |
331 | |
332 // override | |
333 virtual bool refs_discovery_is_mt() const { | |
334 assert(UseParNewGC, "ParNewGeneration only when UseParNewGC"); | |
335 return ParallelGCThreads > 1; | |
336 } | |
337 | |
338 // Make the collection virtual. | |
339 virtual void collect(bool full, | |
340 bool clear_all_soft_refs, | |
341 size_t size, | |
342 bool is_tlab); | |
343 | |
344 // This needs to be visible to the closure function. | |
345 // "obj" is the object to be copied, "m" is a recent value of its mark | |
346 // that must not contain a forwarding pointer (though one might be | |
347 // inserted in "obj"s mark word by a parallel thread). | |
348 inline oop copy_to_survivor_space(ParScanThreadState* par_scan_state, | |
349 oop obj, size_t obj_sz, markOop m) { | |
350 if (_avoid_promotion_undo) { | |
351 return copy_to_survivor_space_avoiding_promotion_undo(par_scan_state, | |
352 obj, obj_sz, m); | |
353 } | |
354 | |
355 return copy_to_survivor_space_with_undo(par_scan_state, obj, obj_sz, m); | |
356 } | |
357 | |
358 oop copy_to_survivor_space_avoiding_promotion_undo(ParScanThreadState* par_scan_state, | |
359 oop obj, size_t obj_sz, markOop m); | |
360 | |
361 oop copy_to_survivor_space_with_undo(ParScanThreadState* par_scan_state, | |
362 oop obj, size_t obj_sz, markOop m); | |
363 | |
364 // Push the given (from-space) object on the global overflow list. | |
365 void push_on_overflow_list(oop from_space_obj); | |
366 | |
367 // If the global overflow list is non-empty, move some tasks from it | |
368 // onto "work_q" (which must be empty). No more than 1/4 of the | |
369 // max_elems of "work_q" are moved. | |
370 bool take_from_overflow_list(ParScanThreadState* par_scan_state); | |
371 | |
372 // The task queues to be used by parallel GC threads. | |
373 ObjToScanQueueSet* task_queues() { | |
374 return _task_queues; | |
375 } | |
376 | |
377 PLABStats* plab_stats() { | |
378 return &_plab_stats; | |
379 } | |
380 | |
381 size_t desired_plab_sz() { | |
382 return _plab_stats.desired_plab_sz(); | |
383 } | |
384 | |
385 static oop real_forwardee(oop obj); | |
386 | |
387 DEBUG_ONLY(static bool is_legal_forward_ptr(oop p);) | |
388 }; |