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annotate src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp @ 1562:dfe27f03244a
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author | trims |
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date | Tue, 01 Jun 2010 11:48:33 -0700 |
parents | c18cbe5936b8 |
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0 | 1 /* |
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2 * Copyright (c) 2002, 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 | |
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 | |
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68 template <class T> void do_oop_work(T* p) { |
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69 assert (!oopDesc::is_null(*p), "expected non-null ref"); |
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70 assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(), |
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71 "expected an oop while scanning weak refs"); |
0 | 72 |
73 // Weak refs may be visited more than once. | |
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74 if (PSScavenge::should_scavenge(p, _to_space)) { |
0 | 75 PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p); |
76 } | |
77 } | |
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78 virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); } |
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79 virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); } |
0 | 80 }; |
81 | |
82 class PSEvacuateFollowersClosure: public VoidClosure { | |
83 private: | |
84 PSPromotionManager* _promotion_manager; | |
85 public: | |
86 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {} | |
87 | |
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88 virtual void do_void() { |
0 | 89 assert(_promotion_manager != NULL, "Sanity"); |
90 _promotion_manager->drain_stacks(true); | |
91 guarantee(_promotion_manager->stacks_empty(), | |
92 "stacks should be empty at this point"); | |
93 } | |
94 }; | |
95 | |
96 class PSPromotionFailedClosure : public ObjectClosure { | |
97 virtual void do_object(oop obj) { | |
98 if (obj->is_forwarded()) { | |
99 obj->init_mark(); | |
100 } | |
101 } | |
102 }; | |
103 | |
104 class PSRefProcTaskProxy: public GCTask { | |
105 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask; | |
106 ProcessTask & _rp_task; | |
107 uint _work_id; | |
108 public: | |
109 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id) | |
110 : _rp_task(rp_task), | |
111 _work_id(work_id) | |
112 { } | |
113 | |
114 private: | |
115 virtual char* name() { return (char *)"Process referents by policy in parallel"; } | |
116 virtual void do_it(GCTaskManager* manager, uint which); | |
117 }; | |
118 | |
119 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which) | |
120 { | |
121 PSPromotionManager* promotion_manager = | |
122 PSPromotionManager::gc_thread_promotion_manager(which); | |
123 assert(promotion_manager != NULL, "sanity check"); | |
124 PSKeepAliveClosure keep_alive(promotion_manager); | |
125 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
126 PSIsAliveClosure is_alive; | |
127 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers); | |
128 } | |
129 | |
130 class PSRefEnqueueTaskProxy: public GCTask { | |
131 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask; | |
132 EnqueueTask& _enq_task; | |
133 uint _work_id; | |
134 | |
135 public: | |
136 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id) | |
137 : _enq_task(enq_task), | |
138 _work_id(work_id) | |
139 { } | |
140 | |
141 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; } | |
142 virtual void do_it(GCTaskManager* manager, uint which) | |
143 { | |
144 _enq_task.work(_work_id); | |
145 } | |
146 }; | |
147 | |
148 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor { | |
149 virtual void execute(ProcessTask& task); | |
150 virtual void execute(EnqueueTask& task); | |
151 }; | |
152 | |
153 void PSRefProcTaskExecutor::execute(ProcessTask& task) | |
154 { | |
155 GCTaskQueue* q = GCTaskQueue::create(); | |
156 for(uint i=0; i<ParallelGCThreads; i++) { | |
157 q->enqueue(new PSRefProcTaskProxy(task, i)); | |
158 } | |
159 ParallelTaskTerminator terminator( | |
160 ParallelScavengeHeap::gc_task_manager()->workers(), | |
161 UseDepthFirstScavengeOrder ? | |
162 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth() | |
163 : (TaskQueueSetSuper*) PSPromotionManager::stack_array_breadth()); | |
164 if (task.marks_oops_alive() && ParallelGCThreads > 1) { | |
165 for (uint j=0; j<ParallelGCThreads; j++) { | |
166 q->enqueue(new StealTask(&terminator)); | |
167 } | |
168 } | |
169 ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); | |
170 } | |
171 | |
172 | |
173 void PSRefProcTaskExecutor::execute(EnqueueTask& task) | |
174 { | |
175 GCTaskQueue* q = GCTaskQueue::create(); | |
176 for(uint i=0; i<ParallelGCThreads; i++) { | |
177 q->enqueue(new PSRefEnqueueTaskProxy(task, i)); | |
178 } | |
179 ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); | |
180 } | |
181 | |
182 // This method contains all heap specific policy for invoking scavenge. | |
183 // PSScavenge::invoke_no_policy() will do nothing but attempt to | |
184 // scavenge. It will not clean up after failed promotions, bail out if | |
185 // we've exceeded policy time limits, or any other special behavior. | |
186 // All such policy should be placed here. | |
187 // | |
188 // Note that this method should only be called from the vm_thread while | |
189 // at a safepoint! | |
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190 void PSScavenge::invoke() { |
0 | 191 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
192 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
193 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
194 | |
195 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
196 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
197 | |
198 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
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199 IsGCActiveMark mark; |
0 | 200 |
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201 bool scavenge_was_done = PSScavenge::invoke_no_policy(); |
0 | 202 |
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203 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
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204 if (UsePerfData) |
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205 counters->update_full_follows_scavenge(0); |
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206 if (!scavenge_was_done || |
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207 policy->should_full_GC(heap->old_gen()->free_in_bytes())) { |
0 | 208 if (UsePerfData) |
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209 counters->update_full_follows_scavenge(full_follows_scavenge); |
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210 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy); |
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211 CollectorPolicy* cp = heap->collector_policy(); |
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212 const bool clear_all_softrefs = cp->should_clear_all_soft_refs(); |
0 | 213 |
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214 if (UseParallelOldGC) { |
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215 PSParallelCompact::invoke_no_policy(clear_all_softrefs); |
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216 } else { |
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217 PSMarkSweep::invoke_no_policy(clear_all_softrefs); |
0 | 218 } |
219 } | |
220 } | |
221 | |
222 // This method contains no policy. You should probably | |
223 // be calling invoke() instead. | |
224 bool PSScavenge::invoke_no_policy() { | |
225 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
226 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
227 | |
228 TimeStamp scavenge_entry; | |
229 TimeStamp scavenge_midpoint; | |
230 TimeStamp scavenge_exit; | |
231 | |
232 scavenge_entry.update(); | |
233 | |
234 if (GC_locker::check_active_before_gc()) { | |
235 return false; | |
236 } | |
237 | |
238 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
239 GCCause::Cause gc_cause = heap->gc_cause(); | |
240 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
241 | |
242 // Check for potential problems. | |
243 if (!should_attempt_scavenge()) { | |
244 return false; | |
245 } | |
246 | |
247 bool promotion_failure_occurred = false; | |
248 | |
249 PSYoungGen* young_gen = heap->young_gen(); | |
250 PSOldGen* old_gen = heap->old_gen(); | |
251 PSPermGen* perm_gen = heap->perm_gen(); | |
252 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); | |
253 heap->increment_total_collections(); | |
254 | |
255 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
256 | |
257 if ((gc_cause != GCCause::_java_lang_system_gc) || | |
258 UseAdaptiveSizePolicyWithSystemGC) { | |
259 // Gather the feedback data for eden occupancy. | |
260 young_gen->eden_space()->accumulate_statistics(); | |
261 } | |
262 | |
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263 if (ZapUnusedHeapArea) { |
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264 // Save information needed to minimize mangling |
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265 heap->record_gen_tops_before_GC(); |
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266 } |
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267 |
0 | 268 if (PrintHeapAtGC) { |
269 Universe::print_heap_before_gc(); | |
270 } | |
271 | |
272 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity"); | |
273 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity"); | |
274 | |
275 size_t prev_used = heap->used(); | |
276 assert(promotion_failed() == false, "Sanity"); | |
277 | |
278 // Fill in TLABs | |
279 heap->accumulate_statistics_all_tlabs(); | |
280 heap->ensure_parsability(true); // retire TLABs | |
281 | |
282 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { | |
283 HandleMark hm; // Discard invalid handles created during verification | |
284 gclog_or_tty->print(" VerifyBeforeGC:"); | |
285 Universe::verify(true); | |
286 } | |
287 | |
288 { | |
289 ResourceMark rm; | |
290 HandleMark hm; | |
291 | |
292 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
293 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
294 TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty); | |
295 TraceCollectorStats tcs(counters()); | |
296 TraceMemoryManagerStats tms(false /* not full GC */); | |
297 | |
298 if (TraceGen0Time) accumulated_time()->start(); | |
299 | |
300 // Let the size policy know we're starting | |
301 size_policy->minor_collection_begin(); | |
302 | |
303 // Verify the object start arrays. | |
304 if (VerifyObjectStartArray && | |
305 VerifyBeforeGC) { | |
306 old_gen->verify_object_start_array(); | |
307 perm_gen->verify_object_start_array(); | |
308 } | |
309 | |
310 // Verify no unmarked old->young roots | |
311 if (VerifyRememberedSets) { | |
312 CardTableExtension::verify_all_young_refs_imprecise(); | |
313 } | |
314 | |
315 if (!ScavengeWithObjectsInToSpace) { | |
316 assert(young_gen->to_space()->is_empty(), | |
317 "Attempt to scavenge with live objects in to_space"); | |
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318 young_gen->to_space()->clear(SpaceDecorator::Mangle); |
0 | 319 } else if (ZapUnusedHeapArea) { |
320 young_gen->to_space()->mangle_unused_area(); | |
321 } | |
322 save_to_space_top_before_gc(); | |
323 | |
324 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
325 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
326 | |
327 reference_processor()->enable_discovery(); | |
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328 reference_processor()->setup_policy(false); |
0 | 329 |
330 // We track how much was promoted to the next generation for | |
331 // the AdaptiveSizePolicy. | |
332 size_t old_gen_used_before = old_gen->used_in_bytes(); | |
333 | |
334 // For PrintGCDetails | |
335 size_t young_gen_used_before = young_gen->used_in_bytes(); | |
336 | |
337 // Reset our survivor overflow. | |
338 set_survivor_overflow(false); | |
339 | |
340 // We need to save the old/perm top values before | |
341 // creating the promotion_manager. We pass the top | |
342 // values to the card_table, to prevent it from | |
343 // straying into the promotion labs. | |
344 HeapWord* old_top = old_gen->object_space()->top(); | |
345 HeapWord* perm_top = perm_gen->object_space()->top(); | |
346 | |
347 // Release all previously held resources | |
348 gc_task_manager()->release_all_resources(); | |
349 | |
350 PSPromotionManager::pre_scavenge(); | |
351 | |
352 // We'll use the promotion manager again later. | |
353 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager(); | |
354 { | |
355 // TraceTime("Roots"); | |
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356 ParallelScavengeHeap::ParStrongRootsScope psrs; |
0 | 357 |
358 GCTaskQueue* q = GCTaskQueue::create(); | |
359 | |
360 for(uint i=0; i<ParallelGCThreads; i++) { | |
361 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i)); | |
362 } | |
363 | |
364 q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top)); | |
365 | |
366 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe)); | |
367 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles)); | |
368 // We scan the thread roots in parallel | |
369 Threads::create_thread_roots_tasks(q); | |
370 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer)); | |
371 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler)); | |
372 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management)); | |
373 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary)); | |
374 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti)); | |
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375 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache)); |
0 | 376 |
377 ParallelTaskTerminator terminator( | |
378 gc_task_manager()->workers(), | |
379 promotion_manager->depth_first() ? | |
380 (TaskQueueSetSuper*) promotion_manager->stack_array_depth() | |
381 : (TaskQueueSetSuper*) promotion_manager->stack_array_breadth()); | |
382 if (ParallelGCThreads>1) { | |
383 for (uint j=0; j<ParallelGCThreads; j++) { | |
384 q->enqueue(new StealTask(&terminator)); | |
385 } | |
386 } | |
387 | |
388 gc_task_manager()->execute_and_wait(q); | |
389 } | |
390 | |
391 scavenge_midpoint.update(); | |
392 | |
393 // Process reference objects discovered during scavenge | |
394 { | |
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395 reference_processor()->setup_policy(false); // not always_clear |
0 | 396 PSKeepAliveClosure keep_alive(promotion_manager); |
397 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
398 if (reference_processor()->processing_is_mt()) { | |
399 PSRefProcTaskExecutor task_executor; | |
400 reference_processor()->process_discovered_references( | |
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401 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor); |
0 | 402 } else { |
403 reference_processor()->process_discovered_references( | |
453
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404 &_is_alive_closure, &keep_alive, &evac_followers, NULL); |
0 | 405 } |
406 } | |
407 | |
408 // Enqueue reference objects discovered during scavenge. | |
409 if (reference_processor()->processing_is_mt()) { | |
410 PSRefProcTaskExecutor task_executor; | |
411 reference_processor()->enqueue_discovered_references(&task_executor); | |
412 } else { | |
413 reference_processor()->enqueue_discovered_references(NULL); | |
414 } | |
415 | |
416 // Finally, flush the promotion_manager's labs, and deallocate its stacks. | |
417 assert(promotion_manager->claimed_stack_empty(), "Sanity"); | |
418 PSPromotionManager::post_scavenge(); | |
419 | |
420 promotion_failure_occurred = promotion_failed(); | |
421 if (promotion_failure_occurred) { | |
422 clean_up_failed_promotion(); | |
423 if (PrintGC) { | |
424 gclog_or_tty->print("--"); | |
425 } | |
426 } | |
427 | |
428 // Let the size policy know we're done. Note that we count promotion | |
429 // failure cleanup time as part of the collection (otherwise, we're | |
430 // implicitly saying it's mutator time). | |
431 size_policy->minor_collection_end(gc_cause); | |
432 | |
433 if (!promotion_failure_occurred) { | |
434 // Swap the survivor spaces. | |
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435 |
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436 |
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437 young_gen->eden_space()->clear(SpaceDecorator::Mangle); |
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438 young_gen->from_space()->clear(SpaceDecorator::Mangle); |
0 | 439 young_gen->swap_spaces(); |
440 | |
441 size_t survived = young_gen->from_space()->used_in_bytes(); | |
442 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before; | |
443 size_policy->update_averages(_survivor_overflow, survived, promoted); | |
444 | |
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445 // A successful scavenge should restart the GC time limit count which is |
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446 // for full GC's. |
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447 size_policy->reset_gc_overhead_limit_count(); |
0 | 448 if (UseAdaptiveSizePolicy) { |
449 // Calculate the new survivor size and tenuring threshold | |
450 | |
451 if (PrintAdaptiveSizePolicy) { | |
452 gclog_or_tty->print("AdaptiveSizeStart: "); | |
453 gclog_or_tty->stamp(); | |
454 gclog_or_tty->print_cr(" collection: %d ", | |
455 heap->total_collections()); | |
456 | |
457 if (Verbose) { | |
458 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
459 " perm_gen_capacity: %d ", | |
460 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
461 perm_gen->capacity_in_bytes()); | |
462 } | |
463 } | |
464 | |
465 | |
466 if (UsePerfData) { | |
467 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
468 counters->update_old_eden_size( | |
469 size_policy->calculated_eden_size_in_bytes()); | |
470 counters->update_old_promo_size( | |
471 size_policy->calculated_promo_size_in_bytes()); | |
472 counters->update_old_capacity(old_gen->capacity_in_bytes()); | |
473 counters->update_young_capacity(young_gen->capacity_in_bytes()); | |
474 counters->update_survived(survived); | |
475 counters->update_promoted(promoted); | |
476 counters->update_survivor_overflowed(_survivor_overflow); | |
477 } | |
478 | |
479 size_t survivor_limit = | |
480 size_policy->max_survivor_size(young_gen->max_size()); | |
481 _tenuring_threshold = | |
482 size_policy->compute_survivor_space_size_and_threshold( | |
483 _survivor_overflow, | |
484 _tenuring_threshold, | |
485 survivor_limit); | |
486 | |
487 if (PrintTenuringDistribution) { | |
488 gclog_or_tty->cr(); | |
489 gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)", | |
490 size_policy->calculated_survivor_size_in_bytes(), | |
491 _tenuring_threshold, MaxTenuringThreshold); | |
492 } | |
493 | |
494 if (UsePerfData) { | |
495 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
496 counters->update_tenuring_threshold(_tenuring_threshold); | |
497 counters->update_survivor_size_counters(); | |
498 } | |
499 | |
500 // Do call at minor collections? | |
501 // Don't check if the size_policy is ready at this | |
502 // level. Let the size_policy check that internally. | |
503 if (UseAdaptiveSizePolicy && | |
504 UseAdaptiveGenerationSizePolicyAtMinorCollection && | |
505 ((gc_cause != GCCause::_java_lang_system_gc) || | |
506 UseAdaptiveSizePolicyWithSystemGC)) { | |
507 | |
508 // Calculate optimial free space amounts | |
509 assert(young_gen->max_size() > | |
510 young_gen->from_space()->capacity_in_bytes() + | |
511 young_gen->to_space()->capacity_in_bytes(), | |
512 "Sizes of space in young gen are out-of-bounds"); | |
513 size_t max_eden_size = young_gen->max_size() - | |
514 young_gen->from_space()->capacity_in_bytes() - | |
515 young_gen->to_space()->capacity_in_bytes(); | |
516 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
517 young_gen->eden_space()->used_in_bytes(), | |
518 old_gen->used_in_bytes(), | |
519 perm_gen->used_in_bytes(), | |
520 young_gen->eden_space()->capacity_in_bytes(), | |
521 old_gen->max_gen_size(), | |
522 max_eden_size, | |
523 false /* full gc*/, | |
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524 gc_cause, |
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525 heap->collector_policy()); |
0 | 526 |
527 } | |
528 // Resize the young generation at every collection | |
529 // even if new sizes have not been calculated. This is | |
530 // to allow resizes that may have been inhibited by the | |
531 // relative location of the "to" and "from" spaces. | |
532 | |
533 // Resizing the old gen at minor collects can cause increases | |
534 // that don't feed back to the generation sizing policy until | |
535 // a major collection. Don't resize the old gen here. | |
536 | |
537 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), | |
538 size_policy->calculated_survivor_size_in_bytes()); | |
539 | |
540 if (PrintAdaptiveSizePolicy) { | |
541 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
542 heap->total_collections()); | |
543 } | |
544 } | |
545 | |
546 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can | |
547 // cause the change of the heap layout. Make sure eden is reshaped if that's the case. | |
548 // Also update() will case adaptive NUMA chunk resizing. | |
549 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now"); | |
550 young_gen->eden_space()->update(); | |
551 | |
552 heap->gc_policy_counters()->update_counters(); | |
553 | |
554 heap->resize_all_tlabs(); | |
555 | |
556 assert(young_gen->to_space()->is_empty(), "to space should be empty now"); | |
557 } | |
558 | |
559 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
560 | |
561 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
562 | |
563 // Re-verify object start arrays | |
564 if (VerifyObjectStartArray && | |
565 VerifyAfterGC) { | |
566 old_gen->verify_object_start_array(); | |
567 perm_gen->verify_object_start_array(); | |
568 } | |
569 | |
570 // Verify all old -> young cards are now precise | |
571 if (VerifyRememberedSets) { | |
572 // Precise verification will give false positives. Until this is fixed, | |
573 // use imprecise verification. | |
574 // CardTableExtension::verify_all_young_refs_precise(); | |
575 CardTableExtension::verify_all_young_refs_imprecise(); | |
576 } | |
577 | |
578 if (TraceGen0Time) accumulated_time()->stop(); | |
579 | |
580 if (PrintGC) { | |
581 if (PrintGCDetails) { | |
582 // Don't print a GC timestamp here. This is after the GC so | |
583 // would be confusing. | |
584 young_gen->print_used_change(young_gen_used_before); | |
585 } | |
586 heap->print_heap_change(prev_used); | |
587 } | |
588 | |
589 // Track memory usage and detect low memory | |
590 MemoryService::track_memory_usage(); | |
591 heap->update_counters(); | |
592 } | |
593 | |
594 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
595 HandleMark hm; // Discard invalid handles created during verification | |
596 gclog_or_tty->print(" VerifyAfterGC:"); | |
597 Universe::verify(false); | |
598 } | |
599 | |
600 if (PrintHeapAtGC) { | |
601 Universe::print_heap_after_gc(); | |
602 } | |
603 | |
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604 if (ZapUnusedHeapArea) { |
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605 young_gen->eden_space()->check_mangled_unused_area_complete(); |
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606 young_gen->from_space()->check_mangled_unused_area_complete(); |
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607 young_gen->to_space()->check_mangled_unused_area_complete(); |
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608 } |
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609 |
0 | 610 scavenge_exit.update(); |
611 | |
612 if (PrintGCTaskTimeStamps) { | |
613 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT, | |
614 scavenge_entry.ticks(), scavenge_midpoint.ticks(), | |
615 scavenge_exit.ticks()); | |
616 gc_task_manager()->print_task_time_stamps(); | |
617 } | |
618 | |
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619 #ifdef TRACESPINNING |
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620 ParallelTaskTerminator::print_termination_counts(); |
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621 #endif |
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622 |
0 | 623 return !promotion_failure_occurred; |
624 } | |
625 | |
626 // This method iterates over all objects in the young generation, | |
627 // unforwarding markOops. It then restores any preserved mark oops, | |
628 // and clears the _preserved_mark_stack. | |
629 void PSScavenge::clean_up_failed_promotion() { | |
630 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
631 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
632 assert(promotion_failed(), "Sanity"); | |
633 | |
634 PSYoungGen* young_gen = heap->young_gen(); | |
635 | |
636 { | |
637 ResourceMark rm; | |
638 | |
639 // Unforward all pointers in the young gen. | |
640 PSPromotionFailedClosure unforward_closure; | |
641 young_gen->object_iterate(&unforward_closure); | |
642 | |
643 if (PrintGC && Verbose) { | |
644 gclog_or_tty->print_cr("Restoring %d marks", | |
645 _preserved_oop_stack->length()); | |
646 } | |
647 | |
648 // Restore any saved marks. | |
649 for (int i=0; i < _preserved_oop_stack->length(); i++) { | |
650 oop obj = _preserved_oop_stack->at(i); | |
651 markOop mark = _preserved_mark_stack->at(i); | |
652 obj->set_mark(mark); | |
653 } | |
654 | |
655 // Deallocate the preserved mark and oop stacks. | |
656 // The stacks were allocated as CHeap objects, so | |
657 // we must call delete to prevent mem leaks. | |
658 delete _preserved_mark_stack; | |
659 _preserved_mark_stack = NULL; | |
660 delete _preserved_oop_stack; | |
661 _preserved_oop_stack = NULL; | |
662 } | |
663 | |
664 // Reset the PromotionFailureALot counters. | |
665 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();) | |
666 } | |
667 | |
668 // This method is called whenever an attempt to promote an object | |
669 // fails. Some markOops will need preserving, some will not. Note | |
670 // that the entire eden is traversed after a failed promotion, with | |
671 // all forwarded headers replaced by the default markOop. This means | |
672 // it is not neccessary to preserve most markOops. | |
673 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) { | |
674 if (_preserved_mark_stack == NULL) { | |
675 ThreadCritical tc; // Lock and retest | |
676 if (_preserved_mark_stack == NULL) { | |
677 assert(_preserved_oop_stack == NULL, "Sanity"); | |
678 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true); | |
679 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true); | |
680 } | |
681 } | |
682 | |
683 // Because we must hold the ThreadCritical lock before using | |
684 // the stacks, we should be safe from observing partial allocations, | |
685 // which are also guarded by the ThreadCritical lock. | |
686 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) { | |
687 ThreadCritical tc; | |
688 _preserved_oop_stack->push(obj); | |
689 _preserved_mark_stack->push(obj_mark); | |
690 } | |
691 } | |
692 | |
693 bool PSScavenge::should_attempt_scavenge() { | |
694 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
695 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
696 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
697 | |
698 if (UsePerfData) { | |
699 counters->update_scavenge_skipped(not_skipped); | |
700 } | |
701 | |
702 PSYoungGen* young_gen = heap->young_gen(); | |
703 PSOldGen* old_gen = heap->old_gen(); | |
704 | |
705 if (!ScavengeWithObjectsInToSpace) { | |
706 // Do not attempt to promote unless to_space is empty | |
707 if (!young_gen->to_space()->is_empty()) { | |
708 _consecutive_skipped_scavenges++; | |
709 if (UsePerfData) { | |
710 counters->update_scavenge_skipped(to_space_not_empty); | |
711 } | |
712 return false; | |
713 } | |
714 } | |
715 | |
716 // Test to see if the scavenge will likely fail. | |
717 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
718 | |
719 // A similar test is done in the policy's should_full_GC(). If this is | |
720 // changed, decide if that test should also be changed. | |
721 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes(); | |
722 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes()); | |
723 bool result = promotion_estimate < old_gen->free_in_bytes(); | |
724 | |
725 if (PrintGCDetails && Verbose) { | |
726 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: "); | |
727 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT | |
728 " padded_average_promoted " SIZE_FORMAT | |
729 " free in old gen " SIZE_FORMAT, | |
730 (size_t) policy->average_promoted_in_bytes(), | |
731 (size_t) policy->padded_average_promoted_in_bytes(), | |
732 old_gen->free_in_bytes()); | |
733 if (young_gen->used_in_bytes() < | |
734 (size_t) policy->padded_average_promoted_in_bytes()) { | |
735 gclog_or_tty->print_cr(" padded_promoted_average is greater" | |
736 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes()); | |
737 } | |
738 } | |
739 | |
740 if (result) { | |
741 _consecutive_skipped_scavenges = 0; | |
742 } else { | |
743 _consecutive_skipped_scavenges++; | |
744 if (UsePerfData) { | |
745 counters->update_scavenge_skipped(promoted_too_large); | |
746 } | |
747 } | |
748 return result; | |
749 } | |
750 | |
751 // Used to add tasks | |
752 GCTaskManager* const PSScavenge::gc_task_manager() { | |
753 assert(ParallelScavengeHeap::gc_task_manager() != NULL, | |
754 "shouldn't return NULL"); | |
755 return ParallelScavengeHeap::gc_task_manager(); | |
756 } | |
757 | |
758 void PSScavenge::initialize() { | |
759 // Arguments must have been parsed | |
760 | |
761 if (AlwaysTenure) { | |
762 _tenuring_threshold = 0; | |
763 } else if (NeverTenure) { | |
764 _tenuring_threshold = markOopDesc::max_age + 1; | |
765 } else { | |
766 // We want to smooth out our startup times for the AdaptiveSizePolicy | |
767 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold : | |
768 MaxTenuringThreshold; | |
769 } | |
770 | |
771 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
772 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
773 | |
774 PSYoungGen* young_gen = heap->young_gen(); | |
775 PSOldGen* old_gen = heap->old_gen(); | |
776 PSPermGen* perm_gen = heap->perm_gen(); | |
777 | |
778 // Set boundary between young_gen and old_gen | |
779 assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(), | |
780 "perm above old"); | |
781 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(), | |
782 "old above young"); | |
783 _young_generation_boundary = young_gen->eden_space()->bottom(); | |
784 | |
785 // Initialize ref handling object for scavenging. | |
786 MemRegion mr = young_gen->reserved(); | |
787 _ref_processor = ReferenceProcessor::create_ref_processor( | |
788 mr, // span | |
789 true, // atomic_discovery | |
790 true, // mt_discovery | |
791 NULL, // is_alive_non_header | |
792 ParallelGCThreads, | |
793 ParallelRefProcEnabled); | |
794 | |
795 // Cache the cardtable | |
796 BarrierSet* bs = Universe::heap()->barrier_set(); | |
797 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind"); | |
798 _card_table = (CardTableExtension*)bs; | |
799 | |
800 _counters = new CollectorCounters("PSScavenge", 0); | |
801 } |