Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp @ 1706:9d7a8ab3736b
6962589: remove breadth first scanning code from parallel gc
Summary: Remove the breadth-first copying order from ParallelScavenge and use depth-first by default.
Reviewed-by: jcoomes, ysr, johnc
author | tonyp |
---|---|
date | Thu, 22 Jul 2010 10:27:41 -0400 |
parents | b2a00dd3117c |
children | 894b1d7c7e01 |
rev | line source |
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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( | |
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160 ParallelScavengeHeap::gc_task_manager()->workers(), |
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161 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth()); |
0 | 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! | |
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188 void PSScavenge::invoke() { |
0 | 189 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
190 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
191 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
192 | |
193 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
194 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
195 | |
196 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
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197 IsGCActiveMark mark; |
0 | 198 |
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199 bool scavenge_was_done = PSScavenge::invoke_no_policy(); |
0 | 200 |
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201 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
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202 if (UsePerfData) |
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203 counters->update_full_follows_scavenge(0); |
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204 if (!scavenge_was_done || |
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205 policy->should_full_GC(heap->old_gen()->free_in_bytes())) { |
0 | 206 if (UsePerfData) |
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207 counters->update_full_follows_scavenge(full_follows_scavenge); |
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208 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy); |
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209 CollectorPolicy* cp = heap->collector_policy(); |
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210 const bool clear_all_softrefs = cp->should_clear_all_soft_refs(); |
0 | 211 |
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212 if (UseParallelOldGC) { |
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213 PSParallelCompact::invoke_no_policy(clear_all_softrefs); |
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214 } else { |
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215 PSMarkSweep::invoke_no_policy(clear_all_softrefs); |
0 | 216 } |
217 } | |
218 } | |
219 | |
220 // This method contains no policy. You should probably | |
221 // be calling invoke() instead. | |
222 bool PSScavenge::invoke_no_policy() { | |
223 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
224 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
225 | |
226 TimeStamp scavenge_entry; | |
227 TimeStamp scavenge_midpoint; | |
228 TimeStamp scavenge_exit; | |
229 | |
230 scavenge_entry.update(); | |
231 | |
232 if (GC_locker::check_active_before_gc()) { | |
233 return false; | |
234 } | |
235 | |
236 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
237 GCCause::Cause gc_cause = heap->gc_cause(); | |
238 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
239 | |
240 // Check for potential problems. | |
241 if (!should_attempt_scavenge()) { | |
242 return false; | |
243 } | |
244 | |
245 bool promotion_failure_occurred = false; | |
246 | |
247 PSYoungGen* young_gen = heap->young_gen(); | |
248 PSOldGen* old_gen = heap->old_gen(); | |
249 PSPermGen* perm_gen = heap->perm_gen(); | |
250 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); | |
251 heap->increment_total_collections(); | |
252 | |
253 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
254 | |
255 if ((gc_cause != GCCause::_java_lang_system_gc) || | |
256 UseAdaptiveSizePolicyWithSystemGC) { | |
257 // Gather the feedback data for eden occupancy. | |
258 young_gen->eden_space()->accumulate_statistics(); | |
259 } | |
260 | |
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261 if (ZapUnusedHeapArea) { |
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262 // Save information needed to minimize mangling |
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263 heap->record_gen_tops_before_GC(); |
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264 } |
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265 |
0 | 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"); | |
263
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316 young_gen->to_space()->clear(SpaceDecorator::Mangle); |
0 | 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(); | |
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326 reference_processor()->setup_policy(false); |
0 | 327 |
328 // We track how much was promoted to the next generation for | |
329 // the AdaptiveSizePolicy. | |
330 size_t old_gen_used_before = old_gen->used_in_bytes(); | |
331 | |
332 // For PrintGCDetails | |
333 size_t young_gen_used_before = young_gen->used_in_bytes(); | |
334 | |
335 // Reset our survivor overflow. | |
336 set_survivor_overflow(false); | |
337 | |
338 // We need to save the old/perm top values before | |
339 // creating the promotion_manager. We pass the top | |
340 // values to the card_table, to prevent it from | |
341 // straying into the promotion labs. | |
342 HeapWord* old_top = old_gen->object_space()->top(); | |
343 HeapWord* perm_top = perm_gen->object_space()->top(); | |
344 | |
345 // Release all previously held resources | |
346 gc_task_manager()->release_all_resources(); | |
347 | |
348 PSPromotionManager::pre_scavenge(); | |
349 | |
350 // We'll use the promotion manager again later. | |
351 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager(); | |
352 { | |
353 // TraceTime("Roots"); | |
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354 ParallelScavengeHeap::ParStrongRootsScope psrs; |
0 | 355 |
356 GCTaskQueue* q = GCTaskQueue::create(); | |
357 | |
358 for(uint i=0; i<ParallelGCThreads; i++) { | |
359 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i)); | |
360 } | |
361 | |
362 q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top)); | |
363 | |
364 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe)); | |
365 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles)); | |
366 // We scan the thread roots in parallel | |
367 Threads::create_thread_roots_tasks(q); | |
368 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer)); | |
369 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler)); | |
370 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management)); | |
371 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary)); | |
372 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti)); | |
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373 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache)); |
0 | 374 |
375 ParallelTaskTerminator terminator( | |
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376 gc_task_manager()->workers(), |
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377 (TaskQueueSetSuper*) promotion_manager->stack_array_depth()); |
0 | 378 if (ParallelGCThreads>1) { |
379 for (uint j=0; j<ParallelGCThreads; j++) { | |
380 q->enqueue(new StealTask(&terminator)); | |
381 } | |
382 } | |
383 | |
384 gc_task_manager()->execute_and_wait(q); | |
385 } | |
386 | |
387 scavenge_midpoint.update(); | |
388 | |
389 // Process reference objects discovered during scavenge | |
390 { | |
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391 reference_processor()->setup_policy(false); // not always_clear |
0 | 392 PSKeepAliveClosure keep_alive(promotion_manager); |
393 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
394 if (reference_processor()->processing_is_mt()) { | |
395 PSRefProcTaskExecutor task_executor; | |
396 reference_processor()->process_discovered_references( | |
453
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397 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor); |
0 | 398 } else { |
399 reference_processor()->process_discovered_references( | |
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400 &_is_alive_closure, &keep_alive, &evac_followers, NULL); |
0 | 401 } |
402 } | |
403 | |
404 // Enqueue reference objects discovered during scavenge. | |
405 if (reference_processor()->processing_is_mt()) { | |
406 PSRefProcTaskExecutor task_executor; | |
407 reference_processor()->enqueue_discovered_references(&task_executor); | |
408 } else { | |
409 reference_processor()->enqueue_discovered_references(NULL); | |
410 } | |
411 | |
412 // Finally, flush the promotion_manager's labs, and deallocate its stacks. | |
413 PSPromotionManager::post_scavenge(); | |
414 | |
415 promotion_failure_occurred = promotion_failed(); | |
416 if (promotion_failure_occurred) { | |
417 clean_up_failed_promotion(); | |
418 if (PrintGC) { | |
419 gclog_or_tty->print("--"); | |
420 } | |
421 } | |
422 | |
423 // Let the size policy know we're done. Note that we count promotion | |
424 // failure cleanup time as part of the collection (otherwise, we're | |
425 // implicitly saying it's mutator time). | |
426 size_policy->minor_collection_end(gc_cause); | |
427 | |
428 if (!promotion_failure_occurred) { | |
429 // Swap the survivor spaces. | |
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430 |
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431 |
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432 young_gen->eden_space()->clear(SpaceDecorator::Mangle); |
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433 young_gen->from_space()->clear(SpaceDecorator::Mangle); |
0 | 434 young_gen->swap_spaces(); |
435 | |
436 size_t survived = young_gen->from_space()->used_in_bytes(); | |
437 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before; | |
438 size_policy->update_averages(_survivor_overflow, survived, promoted); | |
439 | |
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440 // A successful scavenge should restart the GC time limit count which is |
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441 // for full GC's. |
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442 size_policy->reset_gc_overhead_limit_count(); |
0 | 443 if (UseAdaptiveSizePolicy) { |
444 // Calculate the new survivor size and tenuring threshold | |
445 | |
446 if (PrintAdaptiveSizePolicy) { | |
447 gclog_or_tty->print("AdaptiveSizeStart: "); | |
448 gclog_or_tty->stamp(); | |
449 gclog_or_tty->print_cr(" collection: %d ", | |
450 heap->total_collections()); | |
451 | |
452 if (Verbose) { | |
453 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
454 " perm_gen_capacity: %d ", | |
455 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
456 perm_gen->capacity_in_bytes()); | |
457 } | |
458 } | |
459 | |
460 | |
461 if (UsePerfData) { | |
462 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
463 counters->update_old_eden_size( | |
464 size_policy->calculated_eden_size_in_bytes()); | |
465 counters->update_old_promo_size( | |
466 size_policy->calculated_promo_size_in_bytes()); | |
467 counters->update_old_capacity(old_gen->capacity_in_bytes()); | |
468 counters->update_young_capacity(young_gen->capacity_in_bytes()); | |
469 counters->update_survived(survived); | |
470 counters->update_promoted(promoted); | |
471 counters->update_survivor_overflowed(_survivor_overflow); | |
472 } | |
473 | |
474 size_t survivor_limit = | |
475 size_policy->max_survivor_size(young_gen->max_size()); | |
476 _tenuring_threshold = | |
477 size_policy->compute_survivor_space_size_and_threshold( | |
478 _survivor_overflow, | |
479 _tenuring_threshold, | |
480 survivor_limit); | |
481 | |
482 if (PrintTenuringDistribution) { | |
483 gclog_or_tty->cr(); | |
484 gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)", | |
485 size_policy->calculated_survivor_size_in_bytes(), | |
486 _tenuring_threshold, MaxTenuringThreshold); | |
487 } | |
488 | |
489 if (UsePerfData) { | |
490 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
491 counters->update_tenuring_threshold(_tenuring_threshold); | |
492 counters->update_survivor_size_counters(); | |
493 } | |
494 | |
495 // Do call at minor collections? | |
496 // Don't check if the size_policy is ready at this | |
497 // level. Let the size_policy check that internally. | |
498 if (UseAdaptiveSizePolicy && | |
499 UseAdaptiveGenerationSizePolicyAtMinorCollection && | |
500 ((gc_cause != GCCause::_java_lang_system_gc) || | |
501 UseAdaptiveSizePolicyWithSystemGC)) { | |
502 | |
503 // Calculate optimial free space amounts | |
504 assert(young_gen->max_size() > | |
505 young_gen->from_space()->capacity_in_bytes() + | |
506 young_gen->to_space()->capacity_in_bytes(), | |
507 "Sizes of space in young gen are out-of-bounds"); | |
508 size_t max_eden_size = young_gen->max_size() - | |
509 young_gen->from_space()->capacity_in_bytes() - | |
510 young_gen->to_space()->capacity_in_bytes(); | |
511 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
512 young_gen->eden_space()->used_in_bytes(), | |
513 old_gen->used_in_bytes(), | |
514 perm_gen->used_in_bytes(), | |
515 young_gen->eden_space()->capacity_in_bytes(), | |
516 old_gen->max_gen_size(), | |
517 max_eden_size, | |
518 false /* full gc*/, | |
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519 gc_cause, |
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520 heap->collector_policy()); |
0 | 521 |
522 } | |
523 // Resize the young generation at every collection | |
524 // even if new sizes have not been calculated. This is | |
525 // to allow resizes that may have been inhibited by the | |
526 // relative location of the "to" and "from" spaces. | |
527 | |
528 // Resizing the old gen at minor collects can cause increases | |
529 // that don't feed back to the generation sizing policy until | |
530 // a major collection. Don't resize the old gen here. | |
531 | |
532 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), | |
533 size_policy->calculated_survivor_size_in_bytes()); | |
534 | |
535 if (PrintAdaptiveSizePolicy) { | |
536 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
537 heap->total_collections()); | |
538 } | |
539 } | |
540 | |
541 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can | |
542 // cause the change of the heap layout. Make sure eden is reshaped if that's the case. | |
543 // Also update() will case adaptive NUMA chunk resizing. | |
544 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now"); | |
545 young_gen->eden_space()->update(); | |
546 | |
547 heap->gc_policy_counters()->update_counters(); | |
548 | |
549 heap->resize_all_tlabs(); | |
550 | |
551 assert(young_gen->to_space()->is_empty(), "to space should be empty now"); | |
552 } | |
553 | |
554 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
555 | |
556 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
557 | |
558 // Re-verify object start arrays | |
559 if (VerifyObjectStartArray && | |
560 VerifyAfterGC) { | |
561 old_gen->verify_object_start_array(); | |
562 perm_gen->verify_object_start_array(); | |
563 } | |
564 | |
565 // Verify all old -> young cards are now precise | |
566 if (VerifyRememberedSets) { | |
567 // Precise verification will give false positives. Until this is fixed, | |
568 // use imprecise verification. | |
569 // CardTableExtension::verify_all_young_refs_precise(); | |
570 CardTableExtension::verify_all_young_refs_imprecise(); | |
571 } | |
572 | |
573 if (TraceGen0Time) accumulated_time()->stop(); | |
574 | |
575 if (PrintGC) { | |
576 if (PrintGCDetails) { | |
577 // Don't print a GC timestamp here. This is after the GC so | |
578 // would be confusing. | |
579 young_gen->print_used_change(young_gen_used_before); | |
580 } | |
581 heap->print_heap_change(prev_used); | |
582 } | |
583 | |
584 // Track memory usage and detect low memory | |
585 MemoryService::track_memory_usage(); | |
586 heap->update_counters(); | |
587 } | |
588 | |
589 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
590 HandleMark hm; // Discard invalid handles created during verification | |
591 gclog_or_tty->print(" VerifyAfterGC:"); | |
592 Universe::verify(false); | |
593 } | |
594 | |
595 if (PrintHeapAtGC) { | |
596 Universe::print_heap_after_gc(); | |
597 } | |
598 | |
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599 if (ZapUnusedHeapArea) { |
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600 young_gen->eden_space()->check_mangled_unused_area_complete(); |
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601 young_gen->from_space()->check_mangled_unused_area_complete(); |
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602 young_gen->to_space()->check_mangled_unused_area_complete(); |
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603 } |
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604 |
0 | 605 scavenge_exit.update(); |
606 | |
607 if (PrintGCTaskTimeStamps) { | |
608 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT, | |
609 scavenge_entry.ticks(), scavenge_midpoint.ticks(), | |
610 scavenge_exit.ticks()); | |
611 gc_task_manager()->print_task_time_stamps(); | |
612 } | |
613 | |
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614 #ifdef TRACESPINNING |
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615 ParallelTaskTerminator::print_termination_counts(); |
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616 #endif |
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617 |
0 | 618 return !promotion_failure_occurred; |
619 } | |
620 | |
621 // This method iterates over all objects in the young generation, | |
622 // unforwarding markOops. It then restores any preserved mark oops, | |
623 // and clears the _preserved_mark_stack. | |
624 void PSScavenge::clean_up_failed_promotion() { | |
625 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
626 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
627 assert(promotion_failed(), "Sanity"); | |
628 | |
629 PSYoungGen* young_gen = heap->young_gen(); | |
630 | |
631 { | |
632 ResourceMark rm; | |
633 | |
634 // Unforward all pointers in the young gen. | |
635 PSPromotionFailedClosure unforward_closure; | |
636 young_gen->object_iterate(&unforward_closure); | |
637 | |
638 if (PrintGC && Verbose) { | |
639 gclog_or_tty->print_cr("Restoring %d marks", | |
640 _preserved_oop_stack->length()); | |
641 } | |
642 | |
643 // Restore any saved marks. | |
644 for (int i=0; i < _preserved_oop_stack->length(); i++) { | |
645 oop obj = _preserved_oop_stack->at(i); | |
646 markOop mark = _preserved_mark_stack->at(i); | |
647 obj->set_mark(mark); | |
648 } | |
649 | |
650 // Deallocate the preserved mark and oop stacks. | |
651 // The stacks were allocated as CHeap objects, so | |
652 // we must call delete to prevent mem leaks. | |
653 delete _preserved_mark_stack; | |
654 _preserved_mark_stack = NULL; | |
655 delete _preserved_oop_stack; | |
656 _preserved_oop_stack = NULL; | |
657 } | |
658 | |
659 // Reset the PromotionFailureALot counters. | |
660 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();) | |
661 } | |
662 | |
663 // This method is called whenever an attempt to promote an object | |
664 // fails. Some markOops will need preserving, some will not. Note | |
665 // that the entire eden is traversed after a failed promotion, with | |
666 // all forwarded headers replaced by the default markOop. This means | |
667 // it is not neccessary to preserve most markOops. | |
668 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) { | |
669 if (_preserved_mark_stack == NULL) { | |
670 ThreadCritical tc; // Lock and retest | |
671 if (_preserved_mark_stack == NULL) { | |
672 assert(_preserved_oop_stack == NULL, "Sanity"); | |
673 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true); | |
674 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true); | |
675 } | |
676 } | |
677 | |
678 // Because we must hold the ThreadCritical lock before using | |
679 // the stacks, we should be safe from observing partial allocations, | |
680 // which are also guarded by the ThreadCritical lock. | |
681 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) { | |
682 ThreadCritical tc; | |
683 _preserved_oop_stack->push(obj); | |
684 _preserved_mark_stack->push(obj_mark); | |
685 } | |
686 } | |
687 | |
688 bool PSScavenge::should_attempt_scavenge() { | |
689 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
690 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
691 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
692 | |
693 if (UsePerfData) { | |
694 counters->update_scavenge_skipped(not_skipped); | |
695 } | |
696 | |
697 PSYoungGen* young_gen = heap->young_gen(); | |
698 PSOldGen* old_gen = heap->old_gen(); | |
699 | |
700 if (!ScavengeWithObjectsInToSpace) { | |
701 // Do not attempt to promote unless to_space is empty | |
702 if (!young_gen->to_space()->is_empty()) { | |
703 _consecutive_skipped_scavenges++; | |
704 if (UsePerfData) { | |
705 counters->update_scavenge_skipped(to_space_not_empty); | |
706 } | |
707 return false; | |
708 } | |
709 } | |
710 | |
711 // Test to see if the scavenge will likely fail. | |
712 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
713 | |
714 // A similar test is done in the policy's should_full_GC(). If this is | |
715 // changed, decide if that test should also be changed. | |
716 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes(); | |
717 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes()); | |
718 bool result = promotion_estimate < old_gen->free_in_bytes(); | |
719 | |
720 if (PrintGCDetails && Verbose) { | |
721 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: "); | |
722 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT | |
723 " padded_average_promoted " SIZE_FORMAT | |
724 " free in old gen " SIZE_FORMAT, | |
725 (size_t) policy->average_promoted_in_bytes(), | |
726 (size_t) policy->padded_average_promoted_in_bytes(), | |
727 old_gen->free_in_bytes()); | |
728 if (young_gen->used_in_bytes() < | |
729 (size_t) policy->padded_average_promoted_in_bytes()) { | |
730 gclog_or_tty->print_cr(" padded_promoted_average is greater" | |
731 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes()); | |
732 } | |
733 } | |
734 | |
735 if (result) { | |
736 _consecutive_skipped_scavenges = 0; | |
737 } else { | |
738 _consecutive_skipped_scavenges++; | |
739 if (UsePerfData) { | |
740 counters->update_scavenge_skipped(promoted_too_large); | |
741 } | |
742 } | |
743 return result; | |
744 } | |
745 | |
746 // Used to add tasks | |
747 GCTaskManager* const PSScavenge::gc_task_manager() { | |
748 assert(ParallelScavengeHeap::gc_task_manager() != NULL, | |
749 "shouldn't return NULL"); | |
750 return ParallelScavengeHeap::gc_task_manager(); | |
751 } | |
752 | |
753 void PSScavenge::initialize() { | |
754 // Arguments must have been parsed | |
755 | |
756 if (AlwaysTenure) { | |
757 _tenuring_threshold = 0; | |
758 } else if (NeverTenure) { | |
759 _tenuring_threshold = markOopDesc::max_age + 1; | |
760 } else { | |
761 // We want to smooth out our startup times for the AdaptiveSizePolicy | |
762 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold : | |
763 MaxTenuringThreshold; | |
764 } | |
765 | |
766 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
767 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
768 | |
769 PSYoungGen* young_gen = heap->young_gen(); | |
770 PSOldGen* old_gen = heap->old_gen(); | |
771 PSPermGen* perm_gen = heap->perm_gen(); | |
772 | |
773 // Set boundary between young_gen and old_gen | |
774 assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(), | |
775 "perm above old"); | |
776 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(), | |
777 "old above young"); | |
778 _young_generation_boundary = young_gen->eden_space()->bottom(); | |
779 | |
780 // Initialize ref handling object for scavenging. | |
781 MemRegion mr = young_gen->reserved(); | |
782 _ref_processor = ReferenceProcessor::create_ref_processor( | |
783 mr, // span | |
784 true, // atomic_discovery | |
785 true, // mt_discovery | |
786 NULL, // is_alive_non_header | |
787 ParallelGCThreads, | |
788 ParallelRefProcEnabled); | |
789 | |
790 // Cache the cardtable | |
791 BarrierSet* bs = Universe::heap()->barrier_set(); | |
792 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind"); | |
793 _card_table = (CardTableExtension*)bs; | |
794 | |
795 _counters = new CollectorCounters("PSScavenge", 0); | |
796 } |