Mercurial > hg > graal-jvmci-8
comparison src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp @ 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 2002-2007 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 | |
26 # include "incls/_precompiled.incl" | |
27 # include "incls/_psScavenge.cpp.incl" | |
28 | |
29 HeapWord* PSScavenge::_to_space_top_before_gc = NULL; | |
30 int PSScavenge::_consecutive_skipped_scavenges = 0; | |
31 ReferenceProcessor* PSScavenge::_ref_processor = NULL; | |
32 CardTableExtension* PSScavenge::_card_table = NULL; | |
33 bool PSScavenge::_survivor_overflow = false; | |
34 int PSScavenge::_tenuring_threshold = 0; | |
35 HeapWord* PSScavenge::_young_generation_boundary = NULL; | |
36 elapsedTimer PSScavenge::_accumulated_time; | |
37 GrowableArray<markOop>* PSScavenge::_preserved_mark_stack = NULL; | |
38 GrowableArray<oop>* PSScavenge::_preserved_oop_stack = NULL; | |
39 CollectorCounters* PSScavenge::_counters = NULL; | |
40 | |
41 // Define before use | |
42 class PSIsAliveClosure: public BoolObjectClosure { | |
43 public: | |
44 void do_object(oop p) { | |
45 assert(false, "Do not call."); | |
46 } | |
47 bool do_object_b(oop p) { | |
48 return (!PSScavenge::is_obj_in_young((HeapWord*) p)) || p->is_forwarded(); | |
49 } | |
50 }; | |
51 | |
52 PSIsAliveClosure PSScavenge::_is_alive_closure; | |
53 | |
54 class PSKeepAliveClosure: public OopClosure { | |
55 protected: | |
56 MutableSpace* _to_space; | |
57 PSPromotionManager* _promotion_manager; | |
58 | |
59 public: | |
60 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) { | |
61 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
62 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
63 _to_space = heap->young_gen()->to_space(); | |
64 | |
65 assert(_promotion_manager != NULL, "Sanity"); | |
66 } | |
67 | |
68 void do_oop(oop* p) { | |
69 assert (*p != NULL, "expected non-null ref"); | |
70 assert ((*p)->is_oop(), "expected an oop while scanning weak refs"); | |
71 | |
72 oop obj = oop(*p); | |
73 // Weak refs may be visited more than once. | |
74 if (PSScavenge::should_scavenge(obj, _to_space)) { | |
75 PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p); | |
76 } | |
77 } | |
78 }; | |
79 | |
80 class PSEvacuateFollowersClosure: public VoidClosure { | |
81 private: | |
82 PSPromotionManager* _promotion_manager; | |
83 public: | |
84 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {} | |
85 | |
86 void do_void() { | |
87 assert(_promotion_manager != NULL, "Sanity"); | |
88 _promotion_manager->drain_stacks(true); | |
89 guarantee(_promotion_manager->stacks_empty(), | |
90 "stacks should be empty at this point"); | |
91 } | |
92 }; | |
93 | |
94 class PSPromotionFailedClosure : public ObjectClosure { | |
95 virtual void do_object(oop obj) { | |
96 if (obj->is_forwarded()) { | |
97 obj->init_mark(); | |
98 } | |
99 } | |
100 }; | |
101 | |
102 class PSRefProcTaskProxy: public GCTask { | |
103 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask; | |
104 ProcessTask & _rp_task; | |
105 uint _work_id; | |
106 public: | |
107 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id) | |
108 : _rp_task(rp_task), | |
109 _work_id(work_id) | |
110 { } | |
111 | |
112 private: | |
113 virtual char* name() { return (char *)"Process referents by policy in parallel"; } | |
114 virtual void do_it(GCTaskManager* manager, uint which); | |
115 }; | |
116 | |
117 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which) | |
118 { | |
119 PSPromotionManager* promotion_manager = | |
120 PSPromotionManager::gc_thread_promotion_manager(which); | |
121 assert(promotion_manager != NULL, "sanity check"); | |
122 PSKeepAliveClosure keep_alive(promotion_manager); | |
123 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
124 PSIsAliveClosure is_alive; | |
125 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers); | |
126 } | |
127 | |
128 class PSRefEnqueueTaskProxy: public GCTask { | |
129 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask; | |
130 EnqueueTask& _enq_task; | |
131 uint _work_id; | |
132 | |
133 public: | |
134 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id) | |
135 : _enq_task(enq_task), | |
136 _work_id(work_id) | |
137 { } | |
138 | |
139 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; } | |
140 virtual void do_it(GCTaskManager* manager, uint which) | |
141 { | |
142 _enq_task.work(_work_id); | |
143 } | |
144 }; | |
145 | |
146 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor { | |
147 virtual void execute(ProcessTask& task); | |
148 virtual void execute(EnqueueTask& task); | |
149 }; | |
150 | |
151 void PSRefProcTaskExecutor::execute(ProcessTask& task) | |
152 { | |
153 GCTaskQueue* q = GCTaskQueue::create(); | |
154 for(uint i=0; i<ParallelGCThreads; i++) { | |
155 q->enqueue(new PSRefProcTaskProxy(task, i)); | |
156 } | |
157 ParallelTaskTerminator terminator( | |
158 ParallelScavengeHeap::gc_task_manager()->workers(), | |
159 UseDepthFirstScavengeOrder ? | |
160 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth() | |
161 : (TaskQueueSetSuper*) PSPromotionManager::stack_array_breadth()); | |
162 if (task.marks_oops_alive() && ParallelGCThreads > 1) { | |
163 for (uint j=0; j<ParallelGCThreads; j++) { | |
164 q->enqueue(new StealTask(&terminator)); | |
165 } | |
166 } | |
167 ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); | |
168 } | |
169 | |
170 | |
171 void PSRefProcTaskExecutor::execute(EnqueueTask& task) | |
172 { | |
173 GCTaskQueue* q = GCTaskQueue::create(); | |
174 for(uint i=0; i<ParallelGCThreads; i++) { | |
175 q->enqueue(new PSRefEnqueueTaskProxy(task, i)); | |
176 } | |
177 ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); | |
178 } | |
179 | |
180 // This method contains all heap specific policy for invoking scavenge. | |
181 // PSScavenge::invoke_no_policy() will do nothing but attempt to | |
182 // scavenge. It will not clean up after failed promotions, bail out if | |
183 // we've exceeded policy time limits, or any other special behavior. | |
184 // All such policy should be placed here. | |
185 // | |
186 // Note that this method should only be called from the vm_thread while | |
187 // at a safepoint! | |
188 void PSScavenge::invoke() | |
189 { | |
190 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
191 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
192 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
193 | |
194 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
195 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
196 | |
197 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
198 | |
199 // Before each allocation/collection attempt, find out from the | |
200 // policy object if GCs are, on the whole, taking too long. If so, | |
201 // bail out without attempting a collection. | |
202 if (!policy->gc_time_limit_exceeded()) { | |
203 IsGCActiveMark mark; | |
204 | |
205 bool scavenge_was_done = PSScavenge::invoke_no_policy(); | |
206 | |
207 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
208 if (UsePerfData) | |
209 counters->update_full_follows_scavenge(0); | |
210 if (!scavenge_was_done || | |
211 policy->should_full_GC(heap->old_gen()->free_in_bytes())) { | |
212 if (UsePerfData) | |
213 counters->update_full_follows_scavenge(full_follows_scavenge); | |
214 | |
215 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy); | |
216 if (UseParallelOldGC) { | |
217 PSParallelCompact::invoke_no_policy(false); | |
218 } else { | |
219 PSMarkSweep::invoke_no_policy(false); | |
220 } | |
221 } | |
222 } | |
223 } | |
224 | |
225 // This method contains no policy. You should probably | |
226 // be calling invoke() instead. | |
227 bool PSScavenge::invoke_no_policy() { | |
228 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
229 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
230 | |
231 TimeStamp scavenge_entry; | |
232 TimeStamp scavenge_midpoint; | |
233 TimeStamp scavenge_exit; | |
234 | |
235 scavenge_entry.update(); | |
236 | |
237 if (GC_locker::check_active_before_gc()) { | |
238 return false; | |
239 } | |
240 | |
241 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
242 GCCause::Cause gc_cause = heap->gc_cause(); | |
243 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
244 | |
245 // Check for potential problems. | |
246 if (!should_attempt_scavenge()) { | |
247 return false; | |
248 } | |
249 | |
250 bool promotion_failure_occurred = false; | |
251 | |
252 PSYoungGen* young_gen = heap->young_gen(); | |
253 PSOldGen* old_gen = heap->old_gen(); | |
254 PSPermGen* perm_gen = heap->perm_gen(); | |
255 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); | |
256 heap->increment_total_collections(); | |
257 | |
258 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
259 | |
260 if ((gc_cause != GCCause::_java_lang_system_gc) || | |
261 UseAdaptiveSizePolicyWithSystemGC) { | |
262 // Gather the feedback data for eden occupancy. | |
263 young_gen->eden_space()->accumulate_statistics(); | |
264 } | |
265 | |
266 if (PrintHeapAtGC) { | |
267 Universe::print_heap_before_gc(); | |
268 } | |
269 | |
270 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity"); | |
271 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity"); | |
272 | |
273 size_t prev_used = heap->used(); | |
274 assert(promotion_failed() == false, "Sanity"); | |
275 | |
276 // Fill in TLABs | |
277 heap->accumulate_statistics_all_tlabs(); | |
278 heap->ensure_parsability(true); // retire TLABs | |
279 | |
280 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { | |
281 HandleMark hm; // Discard invalid handles created during verification | |
282 gclog_or_tty->print(" VerifyBeforeGC:"); | |
283 Universe::verify(true); | |
284 } | |
285 | |
286 { | |
287 ResourceMark rm; | |
288 HandleMark hm; | |
289 | |
290 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
291 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
292 TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty); | |
293 TraceCollectorStats tcs(counters()); | |
294 TraceMemoryManagerStats tms(false /* not full GC */); | |
295 | |
296 if (TraceGen0Time) accumulated_time()->start(); | |
297 | |
298 // Let the size policy know we're starting | |
299 size_policy->minor_collection_begin(); | |
300 | |
301 // Verify the object start arrays. | |
302 if (VerifyObjectStartArray && | |
303 VerifyBeforeGC) { | |
304 old_gen->verify_object_start_array(); | |
305 perm_gen->verify_object_start_array(); | |
306 } | |
307 | |
308 // Verify no unmarked old->young roots | |
309 if (VerifyRememberedSets) { | |
310 CardTableExtension::verify_all_young_refs_imprecise(); | |
311 } | |
312 | |
313 if (!ScavengeWithObjectsInToSpace) { | |
314 assert(young_gen->to_space()->is_empty(), | |
315 "Attempt to scavenge with live objects in to_space"); | |
316 young_gen->to_space()->clear(); | |
317 } else if (ZapUnusedHeapArea) { | |
318 young_gen->to_space()->mangle_unused_area(); | |
319 } | |
320 save_to_space_top_before_gc(); | |
321 | |
322 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
323 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
324 | |
325 reference_processor()->enable_discovery(); | |
326 | |
327 // We track how much was promoted to the next generation for | |
328 // the AdaptiveSizePolicy. | |
329 size_t old_gen_used_before = old_gen->used_in_bytes(); | |
330 | |
331 // For PrintGCDetails | |
332 size_t young_gen_used_before = young_gen->used_in_bytes(); | |
333 | |
334 // Reset our survivor overflow. | |
335 set_survivor_overflow(false); | |
336 | |
337 // We need to save the old/perm top values before | |
338 // creating the promotion_manager. We pass the top | |
339 // values to the card_table, to prevent it from | |
340 // straying into the promotion labs. | |
341 HeapWord* old_top = old_gen->object_space()->top(); | |
342 HeapWord* perm_top = perm_gen->object_space()->top(); | |
343 | |
344 // Release all previously held resources | |
345 gc_task_manager()->release_all_resources(); | |
346 | |
347 PSPromotionManager::pre_scavenge(); | |
348 | |
349 // We'll use the promotion manager again later. | |
350 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager(); | |
351 { | |
352 // TraceTime("Roots"); | |
353 | |
354 GCTaskQueue* q = GCTaskQueue::create(); | |
355 | |
356 for(uint i=0; i<ParallelGCThreads; i++) { | |
357 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i)); | |
358 } | |
359 | |
360 q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top)); | |
361 | |
362 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe)); | |
363 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles)); | |
364 // We scan the thread roots in parallel | |
365 Threads::create_thread_roots_tasks(q); | |
366 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer)); | |
367 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler)); | |
368 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management)); | |
369 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary)); | |
370 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti)); | |
371 | |
372 ParallelTaskTerminator terminator( | |
373 gc_task_manager()->workers(), | |
374 promotion_manager->depth_first() ? | |
375 (TaskQueueSetSuper*) promotion_manager->stack_array_depth() | |
376 : (TaskQueueSetSuper*) promotion_manager->stack_array_breadth()); | |
377 if (ParallelGCThreads>1) { | |
378 for (uint j=0; j<ParallelGCThreads; j++) { | |
379 q->enqueue(new StealTask(&terminator)); | |
380 } | |
381 } | |
382 | |
383 gc_task_manager()->execute_and_wait(q); | |
384 } | |
385 | |
386 scavenge_midpoint.update(); | |
387 | |
388 // Process reference objects discovered during scavenge | |
389 { | |
390 #ifdef COMPILER2 | |
391 ReferencePolicy *soft_ref_policy = new LRUMaxHeapPolicy(); | |
392 #else | |
393 ReferencePolicy *soft_ref_policy = new LRUCurrentHeapPolicy(); | |
394 #endif // COMPILER2 | |
395 | |
396 PSKeepAliveClosure keep_alive(promotion_manager); | |
397 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
398 assert(soft_ref_policy != NULL,"No soft reference policy"); | |
399 if (reference_processor()->processing_is_mt()) { | |
400 PSRefProcTaskExecutor task_executor; | |
401 reference_processor()->process_discovered_references( | |
402 soft_ref_policy, &_is_alive_closure, &keep_alive, &evac_followers, | |
403 &task_executor); | |
404 } else { | |
405 reference_processor()->process_discovered_references( | |
406 soft_ref_policy, &_is_alive_closure, &keep_alive, &evac_followers, | |
407 NULL); | |
408 } | |
409 } | |
410 | |
411 // Enqueue reference objects discovered during scavenge. | |
412 if (reference_processor()->processing_is_mt()) { | |
413 PSRefProcTaskExecutor task_executor; | |
414 reference_processor()->enqueue_discovered_references(&task_executor); | |
415 } else { | |
416 reference_processor()->enqueue_discovered_references(NULL); | |
417 } | |
418 | |
419 // Finally, flush the promotion_manager's labs, and deallocate its stacks. | |
420 assert(promotion_manager->claimed_stack_empty(), "Sanity"); | |
421 PSPromotionManager::post_scavenge(); | |
422 | |
423 promotion_failure_occurred = promotion_failed(); | |
424 if (promotion_failure_occurred) { | |
425 clean_up_failed_promotion(); | |
426 if (PrintGC) { | |
427 gclog_or_tty->print("--"); | |
428 } | |
429 } | |
430 | |
431 // Let the size policy know we're done. Note that we count promotion | |
432 // failure cleanup time as part of the collection (otherwise, we're | |
433 // implicitly saying it's mutator time). | |
434 size_policy->minor_collection_end(gc_cause); | |
435 | |
436 if (!promotion_failure_occurred) { | |
437 // Swap the survivor spaces. | |
438 young_gen->eden_space()->clear(); | |
439 young_gen->from_space()->clear(); | |
440 young_gen->swap_spaces(); | |
441 | |
442 size_t survived = young_gen->from_space()->used_in_bytes(); | |
443 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before; | |
444 size_policy->update_averages(_survivor_overflow, survived, promoted); | |
445 | |
446 if (UseAdaptiveSizePolicy) { | |
447 // Calculate the new survivor size and tenuring threshold | |
448 | |
449 if (PrintAdaptiveSizePolicy) { | |
450 gclog_or_tty->print("AdaptiveSizeStart: "); | |
451 gclog_or_tty->stamp(); | |
452 gclog_or_tty->print_cr(" collection: %d ", | |
453 heap->total_collections()); | |
454 | |
455 if (Verbose) { | |
456 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
457 " perm_gen_capacity: %d ", | |
458 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
459 perm_gen->capacity_in_bytes()); | |
460 } | |
461 } | |
462 | |
463 | |
464 if (UsePerfData) { | |
465 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
466 counters->update_old_eden_size( | |
467 size_policy->calculated_eden_size_in_bytes()); | |
468 counters->update_old_promo_size( | |
469 size_policy->calculated_promo_size_in_bytes()); | |
470 counters->update_old_capacity(old_gen->capacity_in_bytes()); | |
471 counters->update_young_capacity(young_gen->capacity_in_bytes()); | |
472 counters->update_survived(survived); | |
473 counters->update_promoted(promoted); | |
474 counters->update_survivor_overflowed(_survivor_overflow); | |
475 } | |
476 | |
477 size_t survivor_limit = | |
478 size_policy->max_survivor_size(young_gen->max_size()); | |
479 _tenuring_threshold = | |
480 size_policy->compute_survivor_space_size_and_threshold( | |
481 _survivor_overflow, | |
482 _tenuring_threshold, | |
483 survivor_limit); | |
484 | |
485 if (PrintTenuringDistribution) { | |
486 gclog_or_tty->cr(); | |
487 gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)", | |
488 size_policy->calculated_survivor_size_in_bytes(), | |
489 _tenuring_threshold, MaxTenuringThreshold); | |
490 } | |
491 | |
492 if (UsePerfData) { | |
493 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
494 counters->update_tenuring_threshold(_tenuring_threshold); | |
495 counters->update_survivor_size_counters(); | |
496 } | |
497 | |
498 // Do call at minor collections? | |
499 // Don't check if the size_policy is ready at this | |
500 // level. Let the size_policy check that internally. | |
501 if (UseAdaptiveSizePolicy && | |
502 UseAdaptiveGenerationSizePolicyAtMinorCollection && | |
503 ((gc_cause != GCCause::_java_lang_system_gc) || | |
504 UseAdaptiveSizePolicyWithSystemGC)) { | |
505 | |
506 // Calculate optimial free space amounts | |
507 assert(young_gen->max_size() > | |
508 young_gen->from_space()->capacity_in_bytes() + | |
509 young_gen->to_space()->capacity_in_bytes(), | |
510 "Sizes of space in young gen are out-of-bounds"); | |
511 size_t max_eden_size = young_gen->max_size() - | |
512 young_gen->from_space()->capacity_in_bytes() - | |
513 young_gen->to_space()->capacity_in_bytes(); | |
514 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
515 young_gen->eden_space()->used_in_bytes(), | |
516 old_gen->used_in_bytes(), | |
517 perm_gen->used_in_bytes(), | |
518 young_gen->eden_space()->capacity_in_bytes(), | |
519 old_gen->max_gen_size(), | |
520 max_eden_size, | |
521 false /* full gc*/, | |
522 gc_cause); | |
523 | |
524 } | |
525 // Resize the young generation at every collection | |
526 // even if new sizes have not been calculated. This is | |
527 // to allow resizes that may have been inhibited by the | |
528 // relative location of the "to" and "from" spaces. | |
529 | |
530 // Resizing the old gen at minor collects can cause increases | |
531 // that don't feed back to the generation sizing policy until | |
532 // a major collection. Don't resize the old gen here. | |
533 | |
534 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), | |
535 size_policy->calculated_survivor_size_in_bytes()); | |
536 | |
537 if (PrintAdaptiveSizePolicy) { | |
538 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
539 heap->total_collections()); | |
540 } | |
541 } | |
542 | |
543 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can | |
544 // cause the change of the heap layout. Make sure eden is reshaped if that's the case. | |
545 // Also update() will case adaptive NUMA chunk resizing. | |
546 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now"); | |
547 young_gen->eden_space()->update(); | |
548 | |
549 heap->gc_policy_counters()->update_counters(); | |
550 | |
551 heap->resize_all_tlabs(); | |
552 | |
553 assert(young_gen->to_space()->is_empty(), "to space should be empty now"); | |
554 } | |
555 | |
556 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
557 | |
558 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
559 | |
560 // Re-verify object start arrays | |
561 if (VerifyObjectStartArray && | |
562 VerifyAfterGC) { | |
563 old_gen->verify_object_start_array(); | |
564 perm_gen->verify_object_start_array(); | |
565 } | |
566 | |
567 // Verify all old -> young cards are now precise | |
568 if (VerifyRememberedSets) { | |
569 // Precise verification will give false positives. Until this is fixed, | |
570 // use imprecise verification. | |
571 // CardTableExtension::verify_all_young_refs_precise(); | |
572 CardTableExtension::verify_all_young_refs_imprecise(); | |
573 } | |
574 | |
575 if (TraceGen0Time) accumulated_time()->stop(); | |
576 | |
577 if (PrintGC) { | |
578 if (PrintGCDetails) { | |
579 // Don't print a GC timestamp here. This is after the GC so | |
580 // would be confusing. | |
581 young_gen->print_used_change(young_gen_used_before); | |
582 } | |
583 heap->print_heap_change(prev_used); | |
584 } | |
585 | |
586 // Track memory usage and detect low memory | |
587 MemoryService::track_memory_usage(); | |
588 heap->update_counters(); | |
589 } | |
590 | |
591 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
592 HandleMark hm; // Discard invalid handles created during verification | |
593 gclog_or_tty->print(" VerifyAfterGC:"); | |
594 Universe::verify(false); | |
595 } | |
596 | |
597 if (PrintHeapAtGC) { | |
598 Universe::print_heap_after_gc(); | |
599 } | |
600 | |
601 scavenge_exit.update(); | |
602 | |
603 if (PrintGCTaskTimeStamps) { | |
604 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT, | |
605 scavenge_entry.ticks(), scavenge_midpoint.ticks(), | |
606 scavenge_exit.ticks()); | |
607 gc_task_manager()->print_task_time_stamps(); | |
608 } | |
609 | |
610 return !promotion_failure_occurred; | |
611 } | |
612 | |
613 // This method iterates over all objects in the young generation, | |
614 // unforwarding markOops. It then restores any preserved mark oops, | |
615 // and clears the _preserved_mark_stack. | |
616 void PSScavenge::clean_up_failed_promotion() { | |
617 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
618 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
619 assert(promotion_failed(), "Sanity"); | |
620 | |
621 PSYoungGen* young_gen = heap->young_gen(); | |
622 | |
623 { | |
624 ResourceMark rm; | |
625 | |
626 // Unforward all pointers in the young gen. | |
627 PSPromotionFailedClosure unforward_closure; | |
628 young_gen->object_iterate(&unforward_closure); | |
629 | |
630 if (PrintGC && Verbose) { | |
631 gclog_or_tty->print_cr("Restoring %d marks", | |
632 _preserved_oop_stack->length()); | |
633 } | |
634 | |
635 // Restore any saved marks. | |
636 for (int i=0; i < _preserved_oop_stack->length(); i++) { | |
637 oop obj = _preserved_oop_stack->at(i); | |
638 markOop mark = _preserved_mark_stack->at(i); | |
639 obj->set_mark(mark); | |
640 } | |
641 | |
642 // Deallocate the preserved mark and oop stacks. | |
643 // The stacks were allocated as CHeap objects, so | |
644 // we must call delete to prevent mem leaks. | |
645 delete _preserved_mark_stack; | |
646 _preserved_mark_stack = NULL; | |
647 delete _preserved_oop_stack; | |
648 _preserved_oop_stack = NULL; | |
649 } | |
650 | |
651 // Reset the PromotionFailureALot counters. | |
652 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();) | |
653 } | |
654 | |
655 // This method is called whenever an attempt to promote an object | |
656 // fails. Some markOops will need preserving, some will not. Note | |
657 // that the entire eden is traversed after a failed promotion, with | |
658 // all forwarded headers replaced by the default markOop. This means | |
659 // it is not neccessary to preserve most markOops. | |
660 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) { | |
661 if (_preserved_mark_stack == NULL) { | |
662 ThreadCritical tc; // Lock and retest | |
663 if (_preserved_mark_stack == NULL) { | |
664 assert(_preserved_oop_stack == NULL, "Sanity"); | |
665 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true); | |
666 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true); | |
667 } | |
668 } | |
669 | |
670 // Because we must hold the ThreadCritical lock before using | |
671 // the stacks, we should be safe from observing partial allocations, | |
672 // which are also guarded by the ThreadCritical lock. | |
673 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) { | |
674 ThreadCritical tc; | |
675 _preserved_oop_stack->push(obj); | |
676 _preserved_mark_stack->push(obj_mark); | |
677 } | |
678 } | |
679 | |
680 bool PSScavenge::should_attempt_scavenge() { | |
681 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
682 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
683 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
684 | |
685 if (UsePerfData) { | |
686 counters->update_scavenge_skipped(not_skipped); | |
687 } | |
688 | |
689 PSYoungGen* young_gen = heap->young_gen(); | |
690 PSOldGen* old_gen = heap->old_gen(); | |
691 | |
692 if (!ScavengeWithObjectsInToSpace) { | |
693 // Do not attempt to promote unless to_space is empty | |
694 if (!young_gen->to_space()->is_empty()) { | |
695 _consecutive_skipped_scavenges++; | |
696 if (UsePerfData) { | |
697 counters->update_scavenge_skipped(to_space_not_empty); | |
698 } | |
699 return false; | |
700 } | |
701 } | |
702 | |
703 // Test to see if the scavenge will likely fail. | |
704 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
705 | |
706 // A similar test is done in the policy's should_full_GC(). If this is | |
707 // changed, decide if that test should also be changed. | |
708 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes(); | |
709 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes()); | |
710 bool result = promotion_estimate < old_gen->free_in_bytes(); | |
711 | |
712 if (PrintGCDetails && Verbose) { | |
713 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: "); | |
714 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT | |
715 " padded_average_promoted " SIZE_FORMAT | |
716 " free in old gen " SIZE_FORMAT, | |
717 (size_t) policy->average_promoted_in_bytes(), | |
718 (size_t) policy->padded_average_promoted_in_bytes(), | |
719 old_gen->free_in_bytes()); | |
720 if (young_gen->used_in_bytes() < | |
721 (size_t) policy->padded_average_promoted_in_bytes()) { | |
722 gclog_or_tty->print_cr(" padded_promoted_average is greater" | |
723 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes()); | |
724 } | |
725 } | |
726 | |
727 if (result) { | |
728 _consecutive_skipped_scavenges = 0; | |
729 } else { | |
730 _consecutive_skipped_scavenges++; | |
731 if (UsePerfData) { | |
732 counters->update_scavenge_skipped(promoted_too_large); | |
733 } | |
734 } | |
735 return result; | |
736 } | |
737 | |
738 // Used to add tasks | |
739 GCTaskManager* const PSScavenge::gc_task_manager() { | |
740 assert(ParallelScavengeHeap::gc_task_manager() != NULL, | |
741 "shouldn't return NULL"); | |
742 return ParallelScavengeHeap::gc_task_manager(); | |
743 } | |
744 | |
745 void PSScavenge::initialize() { | |
746 // Arguments must have been parsed | |
747 | |
748 if (AlwaysTenure) { | |
749 _tenuring_threshold = 0; | |
750 } else if (NeverTenure) { | |
751 _tenuring_threshold = markOopDesc::max_age + 1; | |
752 } else { | |
753 // We want to smooth out our startup times for the AdaptiveSizePolicy | |
754 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold : | |
755 MaxTenuringThreshold; | |
756 } | |
757 | |
758 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
759 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
760 | |
761 PSYoungGen* young_gen = heap->young_gen(); | |
762 PSOldGen* old_gen = heap->old_gen(); | |
763 PSPermGen* perm_gen = heap->perm_gen(); | |
764 | |
765 // Set boundary between young_gen and old_gen | |
766 assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(), | |
767 "perm above old"); | |
768 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(), | |
769 "old above young"); | |
770 _young_generation_boundary = young_gen->eden_space()->bottom(); | |
771 | |
772 // Initialize ref handling object for scavenging. | |
773 MemRegion mr = young_gen->reserved(); | |
774 _ref_processor = ReferenceProcessor::create_ref_processor( | |
775 mr, // span | |
776 true, // atomic_discovery | |
777 true, // mt_discovery | |
778 NULL, // is_alive_non_header | |
779 ParallelGCThreads, | |
780 ParallelRefProcEnabled); | |
781 | |
782 // Cache the cardtable | |
783 BarrierSet* bs = Universe::heap()->barrier_set(); | |
784 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind"); | |
785 _card_table = (CardTableExtension*)bs; | |
786 | |
787 _counters = new CollectorCounters("PSScavenge", 0); | |
788 } |