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src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp@2d8a650513c2
src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp
Fri, 29 Apr 2016 00:06:10 +0800
- author
- aoqi
- date
- Fri, 29 Apr 2016 00:06:10 +0800
- changeset 1
- 2d8a650513c2
- parent 0
- f90c822e73f8
- child 25
- 873fd82b133d
- permissions
- -rw-r--r--
Added MIPS 64-bit port.
1 /*
2 * Copyright (c) 2002, 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 /*
26 * This file has been modified by Loongson Technology in 2015. These
27 * modifications are Copyright (c) 2015 Loongson Technology, and are made
28 * available on the same license terms set forth above.
29 */
31 #include "precompiled.hpp"
32 #include "classfile/symbolTable.hpp"
33 #include "code/codeCache.hpp"
34 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
35 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
36 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
37 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
38 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
39 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
40 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
41 #include "gc_implementation/parallelScavenge/psTasks.hpp"
42 #include "gc_implementation/shared/gcHeapSummary.hpp"
43 #include "gc_implementation/shared/gcTimer.hpp"
44 #include "gc_implementation/shared/gcTrace.hpp"
45 #include "gc_implementation/shared/gcTraceTime.hpp"
46 #include "gc_implementation/shared/isGCActiveMark.hpp"
47 #include "gc_implementation/shared/mutableNUMASpace.hpp"
48 #include "gc_implementation/shared/spaceDecorator.hpp"
49 #include "gc_interface/gcCause.hpp"
50 #include "memory/collectorPolicy.hpp"
51 #include "memory/gcLocker.inline.hpp"
52 #include "memory/referencePolicy.hpp"
53 #include "memory/referenceProcessor.hpp"
54 #include "memory/resourceArea.hpp"
55 #include "oops/oop.inline.hpp"
56 #include "oops/oop.psgc.inline.hpp"
57 #include "runtime/biasedLocking.hpp"
58 #include "runtime/fprofiler.hpp"
59 #include "runtime/handles.inline.hpp"
60 #include "runtime/threadCritical.hpp"
61 #include "runtime/vmThread.hpp"
62 #include "runtime/vm_operations.hpp"
63 #include "services/memoryService.hpp"
64 #include "utilities/stack.inline.hpp"
66 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
68 HeapWord* PSScavenge::_to_space_top_before_gc = NULL;
69 int PSScavenge::_consecutive_skipped_scavenges = 0;
70 ReferenceProcessor* PSScavenge::_ref_processor = NULL;
71 CardTableExtension* PSScavenge::_card_table = NULL;
72 bool PSScavenge::_survivor_overflow = false;
73 uint PSScavenge::_tenuring_threshold = 0;
74 HeapWord* PSScavenge::_young_generation_boundary = NULL;
75 uintptr_t PSScavenge::_young_generation_boundary_compressed = 0;
76 elapsedTimer PSScavenge::_accumulated_time;
77 STWGCTimer PSScavenge::_gc_timer;
78 ParallelScavengeTracer PSScavenge::_gc_tracer;
79 Stack<markOop, mtGC> PSScavenge::_preserved_mark_stack;
80 Stack<oop, mtGC> PSScavenge::_preserved_oop_stack;
81 CollectorCounters* PSScavenge::_counters = NULL;
83 // Define before use
84 class PSIsAliveClosure: public BoolObjectClosure {
85 public:
86 bool do_object_b(oop p) {
87 return (!PSScavenge::is_obj_in_young(p)) || p->is_forwarded();
88 }
89 };
91 PSIsAliveClosure PSScavenge::_is_alive_closure;
93 class PSKeepAliveClosure: public OopClosure {
94 protected:
95 MutableSpace* _to_space;
96 PSPromotionManager* _promotion_manager;
98 public:
99 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) {
100 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
101 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
102 _to_space = heap->young_gen()->to_space();
104 assert(_promotion_manager != NULL, "Sanity");
105 }
107 template <class T> void do_oop_work(T* p) {
108 assert (!oopDesc::is_null(*p), "expected non-null ref");
109 assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(),
110 "expected an oop while scanning weak refs");
112 // Weak refs may be visited more than once.
113 if (PSScavenge::should_scavenge(p, _to_space)) {
114 PSScavenge::copy_and_push_safe_barrier<T, /*promote_immediately=*/false>(_promotion_manager, p);
115 }
116 }
117 virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); }
118 virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); }
119 };
121 class PSEvacuateFollowersClosure: public VoidClosure {
122 private:
123 PSPromotionManager* _promotion_manager;
124 public:
125 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {}
127 virtual void do_void() {
128 assert(_promotion_manager != NULL, "Sanity");
129 _promotion_manager->drain_stacks(true);
130 guarantee(_promotion_manager->stacks_empty(),
131 "stacks should be empty at this point");
132 }
133 };
135 class PSPromotionFailedClosure : public ObjectClosure {
136 virtual void do_object(oop obj) {
137 if (obj->is_forwarded()) {
138 obj->init_mark();
139 }
140 }
141 };
143 class PSRefProcTaskProxy: public GCTask {
144 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
145 ProcessTask & _rp_task;
146 uint _work_id;
147 public:
148 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id)
149 : _rp_task(rp_task),
150 _work_id(work_id)
151 { }
153 private:
154 virtual char* name() { return (char *)"Process referents by policy in parallel"; }
155 virtual void do_it(GCTaskManager* manager, uint which);
156 };
158 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which)
159 {
160 PSPromotionManager* promotion_manager =
161 PSPromotionManager::gc_thread_promotion_manager(which);
162 assert(promotion_manager != NULL, "sanity check");
163 PSKeepAliveClosure keep_alive(promotion_manager);
164 PSEvacuateFollowersClosure evac_followers(promotion_manager);
165 PSIsAliveClosure is_alive;
166 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers);
167 }
169 class PSRefEnqueueTaskProxy: public GCTask {
170 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
171 EnqueueTask& _enq_task;
172 uint _work_id;
174 public:
175 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id)
176 : _enq_task(enq_task),
177 _work_id(work_id)
178 { }
180 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; }
181 virtual void do_it(GCTaskManager* manager, uint which)
182 {
183 _enq_task.work(_work_id);
184 }
185 };
187 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
188 virtual void execute(ProcessTask& task);
189 virtual void execute(EnqueueTask& task);
190 };
192 void PSRefProcTaskExecutor::execute(ProcessTask& task)
193 {
194 GCTaskQueue* q = GCTaskQueue::create();
195 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
196 for(uint i=0; i < manager->active_workers(); i++) {
197 q->enqueue(new PSRefProcTaskProxy(task, i));
198 }
199 ParallelTaskTerminator terminator(manager->active_workers(),
200 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth());
201 if (task.marks_oops_alive() && manager->active_workers() > 1) {
202 for (uint j = 0; j < manager->active_workers(); j++) {
203 q->enqueue(new StealTask(&terminator));
204 }
205 }
206 manager->execute_and_wait(q);
207 }
210 void PSRefProcTaskExecutor::execute(EnqueueTask& task)
211 {
212 GCTaskQueue* q = GCTaskQueue::create();
213 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
214 for(uint i=0; i < manager->active_workers(); i++) {
215 q->enqueue(new PSRefEnqueueTaskProxy(task, i));
216 }
217 manager->execute_and_wait(q);
218 }
220 // This method contains all heap specific policy for invoking scavenge.
221 // PSScavenge::invoke_no_policy() will do nothing but attempt to
222 // scavenge. It will not clean up after failed promotions, bail out if
223 // we've exceeded policy time limits, or any other special behavior.
224 // All such policy should be placed here.
225 //
226 // Note that this method should only be called from the vm_thread while
227 // at a safepoint!
228 bool PSScavenge::invoke() {
229 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
230 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
231 assert(!Universe::heap()->is_gc_active(), "not reentrant");
233 ParallelScavengeHeap* const heap = (ParallelScavengeHeap*)Universe::heap();
234 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
236 PSAdaptiveSizePolicy* policy = heap->size_policy();
237 IsGCActiveMark mark;
239 const bool scavenge_done = PSScavenge::invoke_no_policy();
240 bool need_full_gc;
241 if(UseOldNUMA) {
242 need_full_gc = !scavenge_done ||
243 policy->should_full_GC(heap->old_gen()->free_in_bytes_numa());
244 }
245 else {
246 need_full_gc = !scavenge_done ||
247 policy->should_full_GC(heap->old_gen()->free_in_bytes());
248 }
249 bool full_gc_done = false;
251 if (UsePerfData) {
252 PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
253 const int ffs_val = need_full_gc ? full_follows_scavenge : not_skipped;
254 counters->update_full_follows_scavenge(ffs_val);
255 }
257 if (need_full_gc) {
258 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy);
259 CollectorPolicy* cp = heap->collector_policy();
260 const bool clear_all_softrefs = cp->should_clear_all_soft_refs();
262 if (UseParallelOldGC) {
263 full_gc_done = PSParallelCompact::invoke_no_policy(clear_all_softrefs);
264 } else {
265 full_gc_done = PSMarkSweep::invoke_no_policy(clear_all_softrefs);
266 }
267 }
269 return full_gc_done;
270 }
272 /* 2014/7/7 Liao: Add these variables to stastic detail information during GC. */
273 /* Used for objects copy stastic. */
274 float each_gc_copy_time[16];
275 int each_gc_copy_fre[16];
277 /* Used for GC details stastic. */
278 float total_gc_time = 0;
279 int total_gc_fre = 0;
281 /* Used to statstic ThreadRoots optimization. */
282 int task_tag[16];
283 //Used to stastic each cpu
284 int each_total_num[16];
285 int each_eden_total_num[3][16];
286 int each_eden_aligned_num[3][16];
287 //Used to stastic every GC
288 int every_total_num;
289 int every_eden_total_num[3];
290 int every_eden_aligned_num[3];
291 //Used to stastic all the time
292 int all_total_num;
293 int all_eden_total_num[3];
294 int all_eden_aligned_num[3];
296 // This method contains no policy. You should probably
297 // be calling invoke() instead.
298 bool PSScavenge::invoke_no_policy() {
299 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
300 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
302 assert(_preserved_mark_stack.is_empty(), "should be empty");
303 assert(_preserved_oop_stack.is_empty(), "should be empty");
305 _gc_timer.register_gc_start();
307 TimeStamp scavenge_entry;
308 TimeStamp scavenge_midpoint;
309 TimeStamp scavenge_exit;
311 scavenge_entry.update();
313 if (GC_locker::check_active_before_gc()) {
314 return false;
315 }
317 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
318 GCCause::Cause gc_cause = heap->gc_cause();
319 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
321 // Check for potential problems.
322 if (!should_attempt_scavenge()) {
323 return false;
324 }
326 _gc_tracer.report_gc_start(heap->gc_cause(), _gc_timer.gc_start());
328 bool promotion_failure_occurred = false;
330 PSYoungGen* young_gen = heap->young_gen();
331 PSOldGen* old_gen = heap->old_gen();
332 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
334 heap->increment_total_collections();
336 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
338 if ((gc_cause != GCCause::_java_lang_system_gc) ||
339 UseAdaptiveSizePolicyWithSystemGC) {
340 // Gather the feedback data for eden occupancy.
341 young_gen->eden_space()->accumulate_statistics();
342 }
344 if (ZapUnusedHeapArea) {
345 // Save information needed to minimize mangling
346 heap->record_gen_tops_before_GC();
347 }
349 if(UseStasticCopy) {
350 for(uint i = 0; i < ParallelGCThreads; i++) {
351 each_gc_copy_time[i] = 0;
352 each_gc_copy_fre[i] = 0;
353 }
354 }
356 if(UseStasticScavenge) {
357 for(int j = 0; j < 3; j++) {
358 for(uint i = 0; i < ParallelGCThreads; i++) {
359 task_tag[i] = 0;
361 each_total_num[i] = 0;
362 each_eden_total_num[j][i] = 0;
363 each_eden_aligned_num[j][i] = 0;
365 every_total_num = 0;
366 every_eden_total_num[j] = 0;
367 every_eden_aligned_num[j] = 0;
368 }
369 }
370 }
372 heap->print_heap_before_gc();
373 heap->trace_heap_before_gc(&_gc_tracer);
375 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity");
376 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity");
378 size_t prev_used = heap->used();
380 // Fill in TLABs
381 heap->accumulate_statistics_all_tlabs();
382 heap->ensure_parsability(true); // retire TLABs
384 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
385 HandleMark hm; // Discard invalid handles created during verification
386 Universe::verify(" VerifyBeforeGC:");
387 }
389 {
390 ResourceMark rm;
391 HandleMark hm;
393 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
394 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
395 GCTraceTime t1(GCCauseString("GC", gc_cause), PrintGC, !PrintGCDetails, NULL);
396 TraceCollectorStats tcs(counters());
397 TraceMemoryManagerStats tms(false /* not full GC */,gc_cause);
399 if (TraceGen0Time) accumulated_time()->start();
401 // Let the size policy know we're starting
402 size_policy->minor_collection_begin();
404 // Verify the object start arrays.
405 if (VerifyObjectStartArray &&
406 VerifyBeforeGC) {
407 old_gen->verify_object_start_array();
408 }
410 // Verify no unmarked old->young roots
411 if (VerifyRememberedSets) {
412 CardTableExtension::verify_all_young_refs_imprecise();
413 }
415 if (!ScavengeWithObjectsInToSpace) {
416 assert(young_gen->to_space()->is_empty(),
417 "Attempt to scavenge with live objects in to_space");
418 young_gen->to_space()->clear(SpaceDecorator::Mangle);
419 } else if (ZapUnusedHeapArea) {
420 young_gen->to_space()->mangle_unused_area();
421 }
422 save_to_space_top_before_gc();
424 COMPILER2_PRESENT(DerivedPointerTable::clear());
426 reference_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
427 reference_processor()->setup_policy(false);
429 // We track how much was promoted to the next generation for
430 // the AdaptiveSizePolicy.
431 size_t old_gen_used_before = old_gen->used_in_bytes();
433 // For PrintGCDetails
434 size_t young_gen_used_before = young_gen->used_in_bytes();
436 // Reset our survivor overflow.
437 set_survivor_overflow(false);
439 // We need to save the old top values before
440 // creating the promotion_manager. We pass the top
441 // values to the card_table, to prevent it from
442 // straying into the promotion labs.
443 HeapWord* old_top = old_gen->object_space()->top();
445 // Release all previously held resources
446 gc_task_manager()->release_all_resources();
448 // Set the number of GC threads to be used in this collection
449 gc_task_manager()->set_active_gang();
450 gc_task_manager()->task_idle_workers();
451 // Get the active number of workers here and use that value
452 // throughout the methods.
453 uint active_workers = gc_task_manager()->active_workers();
454 heap->set_par_threads(active_workers);
456 PSPromotionManager::pre_scavenge();
458 // We'll use the promotion manager again later.
459 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager();
460 {
461 GCTraceTime tm("Scavenge", false, false, &_gc_timer);
462 ParallelScavengeHeap::ParStrongRootsScope psrs;
464 GCTaskQueue* q = GCTaskQueue::create();
466 if(UseOldNUMA) {
467 MutableSpace* sp;
468 MutableNUMASpace::LGRPSpace *ls;
469 MutableNUMASpace* s = (MutableNUMASpace*) old_gen->object_space();
470 int i, j;
471 i = s->lgrp_spaces()->length();
472 HeapWord** gen_top = (HeapWord**) malloc (i * sizeof(HeapWord));
473 for(j = 0; j < i; j++) {
474 ls = s->lgrp_spaces()->at(j);
475 sp = ls->space();
476 *(gen_top + j) = sp->top();
477 }
479 if (!old_gen->object_space()->is_empty()) {
480 uint stripe_total = active_workers;
481 for(uint i=0; i < stripe_total; i++) {
482 q->enqueue(new OldToYoungRootsTask_OldNUMA(old_gen, gen_top, i, stripe_total));
483 }
484 }
485 }
486 else {
487 if (!old_gen->object_space()->is_empty()) {
488 // There are only old-to-young pointers if there are objects
489 // in the old gen.
490 uint stripe_total = active_workers;
491 for(uint i=0; i < stripe_total; i++) {
492 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i, stripe_total));
493 }
494 }
495 }
497 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe));
498 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles));
499 // We scan the thread roots in parallel
500 Threads::create_thread_roots_tasks(q);
501 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer));
502 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler));
503 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management));
504 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary));
505 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::class_loader_data));
506 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti));
507 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache));
509 ParallelTaskTerminator terminator(
510 active_workers,
511 (TaskQueueSetSuper*) promotion_manager->stack_array_depth());
512 if (active_workers > 1) {
513 for (uint j = 0; j < active_workers; j++) {
514 q->enqueue(new StealTask(&terminator));
515 }
516 }
518 gc_task_manager()->execute_and_wait(q);
519 }
521 scavenge_midpoint.update();
523 // Process reference objects discovered during scavenge
524 {
525 GCTraceTime tm("References", false, false, &_gc_timer);
527 reference_processor()->setup_policy(false); // not always_clear
528 reference_processor()->set_active_mt_degree(active_workers);
529 PSKeepAliveClosure keep_alive(promotion_manager);
530 PSEvacuateFollowersClosure evac_followers(promotion_manager);
531 ReferenceProcessorStats stats;
532 if (reference_processor()->processing_is_mt()) {
533 PSRefProcTaskExecutor task_executor;
534 stats = reference_processor()->process_discovered_references(
535 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor,
536 &_gc_timer);
537 } else {
538 stats = reference_processor()->process_discovered_references(
539 &_is_alive_closure, &keep_alive, &evac_followers, NULL, &_gc_timer);
540 }
542 _gc_tracer.report_gc_reference_stats(stats);
544 // Enqueue reference objects discovered during scavenge.
545 if (reference_processor()->processing_is_mt()) {
546 PSRefProcTaskExecutor task_executor;
547 reference_processor()->enqueue_discovered_references(&task_executor);
548 } else {
549 reference_processor()->enqueue_discovered_references(NULL);
550 }
551 }
553 {
554 GCTraceTime tm("StringTable", false, false, &_gc_timer);
555 // Unlink any dead interned Strings and process the remaining live ones.
556 PSScavengeRootsClosure root_closure(promotion_manager);
557 StringTable::unlink_or_oops_do(&_is_alive_closure, &root_closure);
558 }
560 // Finally, flush the promotion_manager's labs, and deallocate its stacks.
561 promotion_failure_occurred = PSPromotionManager::post_scavenge(_gc_tracer);
562 if (promotion_failure_occurred) {
563 clean_up_failed_promotion();
564 if (PrintGC) {
565 gclog_or_tty->print("--");
566 }
567 }
569 // Let the size policy know we're done. Note that we count promotion
570 // failure cleanup time as part of the collection (otherwise, we're
571 // implicitly saying it's mutator time).
572 size_policy->minor_collection_end(gc_cause);
574 if (!promotion_failure_occurred) {
575 // Swap the survivor spaces.
576 young_gen->eden_space()->clear(SpaceDecorator::Mangle);
577 young_gen->from_space()->clear(SpaceDecorator::Mangle);
578 young_gen->swap_spaces();
580 size_t survived = young_gen->from_space()->used_in_bytes();
581 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before;
582 size_policy->update_averages(_survivor_overflow, survived, promoted);
584 // A successful scavenge should restart the GC time limit count which is
585 // for full GC's.
586 size_policy->reset_gc_overhead_limit_count();
587 if (UseAdaptiveSizePolicy) {
588 // Calculate the new survivor size and tenuring threshold
590 if (PrintAdaptiveSizePolicy) {
591 gclog_or_tty->print("AdaptiveSizeStart: ");
592 gclog_or_tty->stamp();
593 gclog_or_tty->print_cr(" collection: %d ",
594 heap->total_collections());
596 if (Verbose) {
597 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d",
598 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
599 }
600 }
603 if (UsePerfData) {
604 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
605 counters->update_old_eden_size(
606 size_policy->calculated_eden_size_in_bytes());
607 counters->update_old_promo_size(
608 size_policy->calculated_promo_size_in_bytes());
609 counters->update_old_capacity(old_gen->capacity_in_bytes());
610 counters->update_young_capacity(young_gen->capacity_in_bytes());
611 counters->update_survived(survived);
612 counters->update_promoted(promoted);
613 counters->update_survivor_overflowed(_survivor_overflow);
614 }
616 size_t max_young_size = young_gen->max_size();
618 // Deciding a free ratio in the young generation is tricky, so if
619 // MinHeapFreeRatio or MaxHeapFreeRatio are in use (implicating
620 // that the old generation size may have been limited because of them) we
621 // should then limit our young generation size using NewRatio to have it
622 // follow the old generation size.
623 if (MinHeapFreeRatio != 0 || MaxHeapFreeRatio != 100) {
624 max_young_size = MIN2(old_gen->capacity_in_bytes() / NewRatio, young_gen->max_size());
625 }
627 size_t survivor_limit =
628 size_policy->max_survivor_size(max_young_size);
629 _tenuring_threshold =
630 size_policy->compute_survivor_space_size_and_threshold(
631 _survivor_overflow,
632 _tenuring_threshold,
633 survivor_limit);
635 if (PrintTenuringDistribution) {
636 gclog_or_tty->cr();
637 gclog_or_tty->print_cr("Desired survivor size " SIZE_FORMAT " bytes, new threshold %u (max %u)",
638 size_policy->calculated_survivor_size_in_bytes(),
639 _tenuring_threshold, MaxTenuringThreshold);
640 }
642 if (UsePerfData) {
643 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
644 counters->update_tenuring_threshold(_tenuring_threshold);
645 counters->update_survivor_size_counters();
646 }
648 // Do call at minor collections?
649 // Don't check if the size_policy is ready at this
650 // level. Let the size_policy check that internally.
651 if (UseAdaptiveGenerationSizePolicyAtMinorCollection &&
652 ((gc_cause != GCCause::_java_lang_system_gc) ||
653 UseAdaptiveSizePolicyWithSystemGC)) {
655 // Calculate optimial free space amounts
656 assert(young_gen->max_size() >
657 young_gen->from_space()->capacity_in_bytes() +
658 young_gen->to_space()->capacity_in_bytes(),
659 "Sizes of space in young gen are out-of-bounds");
661 size_t young_live = young_gen->used_in_bytes();
662 size_t eden_live = young_gen->eden_space()->used_in_bytes();
663 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
664 size_t max_old_gen_size = old_gen->max_gen_size();
665 size_t max_eden_size = max_young_size -
666 young_gen->from_space()->capacity_in_bytes() -
667 young_gen->to_space()->capacity_in_bytes();
669 // Used for diagnostics
670 size_policy->clear_generation_free_space_flags();
672 size_policy->compute_eden_space_size(young_live,
673 eden_live,
674 cur_eden,
675 max_eden_size,
676 false /* not full gc*/);
678 size_policy->check_gc_overhead_limit(young_live,
679 eden_live,
680 max_old_gen_size,
681 max_eden_size,
682 false /* not full gc*/,
683 gc_cause,
684 heap->collector_policy());
686 size_policy->decay_supplemental_growth(false /* not full gc*/);
687 }
688 // Resize the young generation at every collection
689 // even if new sizes have not been calculated. This is
690 // to allow resizes that may have been inhibited by the
691 // relative location of the "to" and "from" spaces.
693 // Resizing the old gen at minor collects can cause increases
694 // that don't feed back to the generation sizing policy until
695 // a major collection. Don't resize the old gen here.
697 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
698 size_policy->calculated_survivor_size_in_bytes());
700 if (PrintAdaptiveSizePolicy) {
701 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
702 heap->total_collections());
703 }
704 }
706 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can
707 // cause the change of the heap layout. Make sure eden is reshaped if that's the case.
708 // Also update() will case adaptive NUMA chunk resizing.
709 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now");
710 young_gen->eden_space()->update();
712 heap->gc_policy_counters()->update_counters();
714 heap->resize_all_tlabs();
716 assert(young_gen->to_space()->is_empty(), "to space should be empty now");
717 }
719 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
721 NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
723 {
724 GCTraceTime tm("Prune Scavenge Root Methods", false, false, &_gc_timer);
726 CodeCache::prune_scavenge_root_nmethods();
727 }
729 // Re-verify object start arrays
730 if (VerifyObjectStartArray &&
731 VerifyAfterGC) {
732 old_gen->verify_object_start_array();
733 }
735 // Verify all old -> young cards are now precise
736 if (VerifyRememberedSets) {
737 // Precise verification will give false positives. Until this is fixed,
738 // use imprecise verification.
739 // CardTableExtension::verify_all_young_refs_precise();
740 CardTableExtension::verify_all_young_refs_imprecise();
741 }
743 if (TraceGen0Time) accumulated_time()->stop();
745 if (PrintGC) {
746 if (PrintGCDetails) {
747 // Don't print a GC timestamp here. This is after the GC so
748 // would be confusing.
749 young_gen->print_used_change(young_gen_used_before);
750 }
751 heap->print_heap_change(prev_used);
752 }
754 // Track memory usage and detect low memory
755 MemoryService::track_memory_usage();
756 heap->update_counters();
758 gc_task_manager()->release_idle_workers();
759 }
761 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
762 HandleMark hm; // Discard invalid handles created during verification
763 Universe::verify(" VerifyAfterGC:");
764 }
766 heap->print_heap_after_gc();
767 heap->trace_heap_after_gc(&_gc_tracer);
768 _gc_tracer.report_tenuring_threshold(tenuring_threshold());
770 if (ZapUnusedHeapArea) {
771 young_gen->eden_space()->check_mangled_unused_area_complete();
772 young_gen->from_space()->check_mangled_unused_area_complete();
773 young_gen->to_space()->check_mangled_unused_area_complete();
774 }
776 scavenge_exit.update();
778 if (PrintGCTaskTimeStamps) {
779 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT,
780 scavenge_entry.ticks(), scavenge_midpoint.ticks(),
781 scavenge_exit.ticks());
782 gc_task_manager()->print_task_time_stamps();
783 }
785 if(PrintGCDetails) {
786 float young_gc_time;
787 total_gc_fre++;
788 young_gc_time = ((float)(scavenge_exit.ticks() - scavenge_entry.ticks()))/1e9;
789 total_gc_time = total_gc_time + ((float)(scavenge_exit.ticks() - scavenge_entry.ticks()))/1e9;
790 tty->print_cr("total_gc_fre = %d, young_gc_time = %f, total_gc_time = %f", total_gc_fre, young_gc_time, total_gc_time);
791 }
793 if(UseStasticCopy) {
794 for(uint i = 0; i < ParallelGCThreads; i++) {
795 tty->print_cr("each_gc_copy_time[%d] = %f", i, each_gc_copy_time[i]/each_gc_copy_fre[i]);
796 }
797 tty->print_cr("");
798 for(uint i = 0; i < ParallelGCThreads; i++) {
799 tty->print_cr("each_gc_copy_fre[%d] = %d", i, each_gc_copy_fre[i]);
800 }
801 }
803 if(UseStasticScavenge) {
804 for(int i = 0; i < 3; i++) {
805 for(uint j = 0; j < ParallelGCThreads; j++) {
806 every_eden_total_num[i] += each_eden_total_num[i][j];
807 every_eden_aligned_num[i] += each_eden_aligned_num[i][j];
808 }
809 }
811 for(uint i = 0; i < ParallelGCThreads; i++) {
812 every_total_num += each_total_num[i];
813 }
815 all_total_num += every_total_num;
817 for(int i = 0; i < 3; i++) {
818 all_eden_total_num[i] += every_eden_total_num[i];
819 all_eden_aligned_num[i] += every_eden_aligned_num[i];
820 }
822 tty->print_cr("============= Every GCDetails: =============");
823 tty->print_cr("ThreadRootTask: prop of all = %f, prop of aligned = %f", (float)every_eden_total_num[0]/(float)every_total_num, (float)every_eden_aligned_num[0]/(float)every_eden_total_num[0]);
824 tty->print_cr("OldToYoungRootTask: prop of all = %f, prop of aligned = %f", (float)every_eden_total_num[1]/(float)every_total_num, (float)every_eden_aligned_num[1]/(float)every_eden_total_num[1]);
825 tty->print_cr("StealTask: prop of all = %f, prop of aligned = %f", (float)every_eden_total_num[2]/(float)every_total_num, (float)every_eden_aligned_num[2]/(float)every_eden_total_num[2]);
826 tty->print_cr("");
828 tty->print_cr("============= Total GCDetails: =============");
829 tty->print_cr("ThreadRootTask: prop of all = %f, prop of aligned = %f", (float)all_eden_total_num[0]/(float)all_total_num, (float)all_eden_aligned_num[0]/(float)all_eden_total_num[0]);
830 tty->print_cr("OldToYoungRootTask: prop of all = %f, prop of aligned = %f", (float)all_eden_total_num[1]/(float)all_total_num, (float)all_eden_aligned_num[1]/(float)all_eden_total_num[1]);
831 tty->print_cr("StealTask: prop of all = %f, prop of aligned = %f", (float)all_eden_total_num[2]/(float)all_total_num, (float)all_eden_aligned_num[2]/(float)all_eden_total_num[2]);
832 tty->print_cr("");
833 }
835 #ifdef TRACESPINNING
836 ParallelTaskTerminator::print_termination_counts();
837 #endif
840 _gc_timer.register_gc_end();
842 _gc_tracer.report_gc_end(_gc_timer.gc_end(), _gc_timer.time_partitions());
844 return !promotion_failure_occurred;
845 }
847 // This method iterates over all objects in the young generation,
848 // unforwarding markOops. It then restores any preserved mark oops,
849 // and clears the _preserved_mark_stack.
850 void PSScavenge::clean_up_failed_promotion() {
851 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
852 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
854 PSYoungGen* young_gen = heap->young_gen();
856 {
857 ResourceMark rm;
859 // Unforward all pointers in the young gen.
860 PSPromotionFailedClosure unforward_closure;
861 young_gen->object_iterate(&unforward_closure);
863 if (PrintGC && Verbose) {
864 gclog_or_tty->print_cr("Restoring %d marks", _preserved_oop_stack.size());
865 }
867 // Restore any saved marks.
868 while (!_preserved_oop_stack.is_empty()) {
869 oop obj = _preserved_oop_stack.pop();
870 markOop mark = _preserved_mark_stack.pop();
871 obj->set_mark(mark);
872 }
874 // Clear the preserved mark and oop stack caches.
875 _preserved_mark_stack.clear(true);
876 _preserved_oop_stack.clear(true);
877 }
879 // Reset the PromotionFailureALot counters.
880 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
881 }
883 // This method is called whenever an attempt to promote an object
884 // fails. Some markOops will need preservation, some will not. Note
885 // that the entire eden is traversed after a failed promotion, with
886 // all forwarded headers replaced by the default markOop. This means
887 // it is not necessary to preserve most markOops.
888 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) {
889 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) {
890 // Should use per-worker private stacks here rather than
891 // locking a common pair of stacks.
892 ThreadCritical tc;
893 _preserved_oop_stack.push(obj);
894 _preserved_mark_stack.push(obj_mark);
895 }
896 }
898 bool PSScavenge::should_attempt_scavenge() {
899 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
900 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
901 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters();
903 if (UsePerfData) {
904 counters->update_scavenge_skipped(not_skipped);
905 }
907 PSYoungGen* young_gen = heap->young_gen();
908 PSOldGen* old_gen = heap->old_gen();
910 if (!ScavengeWithObjectsInToSpace) {
911 // Do not attempt to promote unless to_space is empty
912 if (!young_gen->to_space()->is_empty()) {
913 _consecutive_skipped_scavenges++;
914 if (UsePerfData) {
915 counters->update_scavenge_skipped(to_space_not_empty);
916 }
917 return false;
918 }
919 }
921 // Test to see if the scavenge will likely fail.
922 PSAdaptiveSizePolicy* policy = heap->size_policy();
924 // A similar test is done in the policy's should_full_GC(). If this is
925 // changed, decide if that test should also be changed.
926 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes();
927 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes());
928 bool result = promotion_estimate < old_gen->free_in_bytes();
930 if (PrintGCDetails && Verbose) {
931 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: ");
932 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
933 " padded_average_promoted " SIZE_FORMAT
934 " free in old gen " SIZE_FORMAT,
935 (size_t) policy->average_promoted_in_bytes(),
936 (size_t) policy->padded_average_promoted_in_bytes(),
937 old_gen->free_in_bytes());
938 if (young_gen->used_in_bytes() <
939 (size_t) policy->padded_average_promoted_in_bytes()) {
940 gclog_or_tty->print_cr(" padded_promoted_average is greater"
941 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes());
942 }
943 }
945 if (result) {
946 _consecutive_skipped_scavenges = 0;
947 } else {
948 _consecutive_skipped_scavenges++;
949 if (UsePerfData) {
950 counters->update_scavenge_skipped(promoted_too_large);
951 }
952 }
953 return result;
954 }
956 // Used to add tasks
957 GCTaskManager* const PSScavenge::gc_task_manager() {
958 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
959 "shouldn't return NULL");
960 return ParallelScavengeHeap::gc_task_manager();
961 }
963 void PSScavenge::initialize() {
964 // Arguments must have been parsed
966 if (AlwaysTenure) {
967 _tenuring_threshold = 0;
968 } else if (NeverTenure) {
969 _tenuring_threshold = markOopDesc::max_age + 1;
970 } else {
971 // We want to smooth out our startup times for the AdaptiveSizePolicy
972 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold :
973 MaxTenuringThreshold;
974 }
976 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
977 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
979 PSYoungGen* young_gen = heap->young_gen();
980 PSOldGen* old_gen = heap->old_gen();
982 // Set boundary between young_gen and old_gen
983 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(),
984 "old above young");
985 set_young_generation_boundary(young_gen->eden_space()->bottom());
987 // Initialize ref handling object for scavenging.
988 MemRegion mr = young_gen->reserved();
990 _ref_processor =
991 new ReferenceProcessor(mr, // span
992 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
993 (int) ParallelGCThreads, // mt processing degree
994 true, // mt discovery
995 (int) ParallelGCThreads, // mt discovery degree
996 true, // atomic_discovery
997 NULL); // header provides liveness info
999 // Cache the cardtable
1000 BarrierSet* bs = Universe::heap()->barrier_set();
1001 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind");
1002 _card_table = (CardTableExtension*)bs;
1004 _counters = new CollectorCounters("PSScavenge", 0);
1005 }
