1 /*
2 * Copyright (c) 2001, 2019, 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 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classLoaderDataGraph.hpp"
28 #include "classfile/stringTable.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "code/codeCache.hpp"
32 #include "gc/parallel/parallelScavengeHeap.hpp"
33 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
34 #include "gc/parallel/psMarkSweep.hpp"
35 #include "gc/parallel/psMarkSweepDecorator.hpp"
36 #include "gc/parallel/psOldGen.hpp"
37 #include "gc/parallel/psScavenge.hpp"
38 #include "gc/parallel/psYoungGen.hpp"
39 #include "gc/serial/markSweep.hpp"
40 #include "gc/shared/gcCause.hpp"
41 #include "gc/shared/gcHeapSummary.hpp"
42 #include "gc/shared/gcId.hpp"
43 #include "gc/shared/gcLocker.hpp"
44 #include "gc/shared/gcTimer.hpp"
45 #include "gc/shared/gcTrace.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "gc/shared/isGCActiveMark.hpp"
48 #include "gc/shared/referencePolicy.hpp"
49 #include "gc/shared/referenceProcessor.hpp"
50 #include "gc/shared/referenceProcessorPhaseTimes.hpp"
51 #include "gc/shared/spaceDecorator.hpp"
52 #include "gc/shared/weakProcessor.hpp"
53 #include "memory/universe.hpp"
54 #include "logging/log.hpp"
55 #include "oops/oop.inline.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/flags/flagSetting.hpp"
58 #include "runtime/handles.inline.hpp"
59 #include "runtime/safepoint.hpp"
60 #include "runtime/vmThread.hpp"
61 #include "services/management.hpp"
62 #include "services/memoryService.hpp"
63 #include "utilities/align.hpp"
64 #include "utilities/events.inline.hpp"
65 #include "utilities/stack.inline.hpp"
66 #if INCLUDE_JVMCI
67 #include "jvmci/jvmci.hpp"
68 #endif
69
70 elapsedTimer PSMarkSweep::_accumulated_time;
71 jlong PSMarkSweep::_time_of_last_gc = 0;
72 CollectorCounters* PSMarkSweep::_counters = NULL;
73
74 SpanSubjectToDiscoveryClosure PSMarkSweep::_span_based_discoverer;
75
76 void PSMarkSweep::initialize() {
77 _span_based_discoverer.set_span(ParallelScavengeHeap::heap()->reserved_region());
78 set_ref_processor(new ReferenceProcessor(&_span_based_discoverer)); // a vanilla ref proc
79 _counters = new CollectorCounters("Serial full collection pauses", 1);
80 MarkSweep::initialize();
81 }
82
83 // This method contains all heap specific policy for invoking mark sweep.
84 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact
85 // the heap. It will do nothing further. If we need to bail out for policy
86 // reasons, scavenge before full gc, or any other specialized behavior, it
87 // needs to be added here.
88 //
89 // Note that this method should only be called from the vm_thread while
90 // at a safepoint!
91 //
92 // Note that the all_soft_refs_clear flag in the soft ref policy
93 // may be true because this method can be called without intervening
94 // activity. For example when the heap space is tight and full measure
95 // are being taken to free space.
96
97 void PSMarkSweep::invoke(bool maximum_heap_compaction) {
98 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
99 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
100 assert(!ParallelScavengeHeap::heap()->is_gc_active(), "not reentrant");
101
102 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
103 GCCause::Cause gc_cause = heap->gc_cause();
104 PSAdaptiveSizePolicy* policy = heap->size_policy();
105 IsGCActiveMark mark;
106
107 if (ScavengeBeforeFullGC) {
108 PSScavenge::invoke_no_policy();
109 }
110
111 const bool clear_all_soft_refs =
112 heap->soft_ref_policy()->should_clear_all_soft_refs();
113
114 uint count = maximum_heap_compaction ? 1 : MarkSweepAlwaysCompactCount;
115 UIntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count);
116 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction);
117 }
118
119 // This method contains no policy. You should probably
120 // be calling invoke() instead.
121 bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
122 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
123 assert(ref_processor() != NULL, "Sanity");
124
125 if (GCLocker::check_active_before_gc()) {
126 return false;
127 }
128
129 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
130 GCCause::Cause gc_cause = heap->gc_cause();
131
132 GCIdMark gc_id_mark;
133 _gc_timer->register_gc_start();
134 _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start());
135
136 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
137
138 // The scope of casr should end after code that can change
139 // SoftRefolicy::_should_clear_all_soft_refs.
140 ClearedAllSoftRefs casr(clear_all_softrefs, heap->soft_ref_policy());
141
142 PSYoungGen* young_gen = heap->young_gen();
143 PSOldGen* old_gen = heap->old_gen();
144
145 // Increment the invocation count
146 heap->increment_total_collections(true /* full */);
147
148 // Save information needed to minimize mangling
149 heap->record_gen_tops_before_GC();
150
151 // We need to track unique mark sweep invocations as well.
152 _total_invocations++;
153
154 heap->print_heap_before_gc();
155 heap->trace_heap_before_gc(_gc_tracer);
156
157 // Fill in TLABs
158 heap->ensure_parsability(true); // retire TLABs
159
160 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
161 HandleMark hm; // Discard invalid handles created during verification
162 Universe::verify("Before GC");
163 }
164
165 // Verify object start arrays
166 if (VerifyObjectStartArray &&
167 VerifyBeforeGC) {
168 old_gen->verify_object_start_array();
169 }
170
171 // Filled in below to track the state of the young gen after the collection.
172 bool eden_empty;
173 bool survivors_empty;
174 bool young_gen_empty;
175
176 {
177 HandleMark hm;
178
179 GCTraceCPUTime tcpu;
180 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause, true);
181
182 heap->pre_full_gc_dump(_gc_timer);
183
184 TraceCollectorStats tcs(counters());
185 TraceMemoryManagerStats tms(heap->old_gc_manager(),gc_cause);
186
187 if (log_is_enabled(Debug, gc, heap, exit)) {
188 accumulated_time()->start();
189 }
190
191 // Let the size policy know we're starting
192 size_policy->major_collection_begin();
193
194 BiasedLocking::preserve_marks();
195
196 const PreGenGCValues pre_gc_values = heap->get_pre_gc_values();
197
198 allocate_stacks();
199
200 #if COMPILER2_OR_JVMCI
201 DerivedPointerTable::clear();
202 #endif
203
204 ref_processor()->enable_discovery();
205 ref_processor()->setup_policy(clear_all_softrefs);
206
207 mark_sweep_phase1(clear_all_softrefs);
208
209 mark_sweep_phase2();
210
211 #if COMPILER2_OR_JVMCI
212 // Don't add any more derived pointers during phase3
213 assert(DerivedPointerTable::is_active(), "Sanity");
214 DerivedPointerTable::set_active(false);
215 #endif
216
217 mark_sweep_phase3();
218
219 mark_sweep_phase4();
220
221 restore_marks();
222
223 deallocate_stacks();
224
225 if (ZapUnusedHeapArea) {
226 // Do a complete mangle (top to end) because the usage for
227 // scratch does not maintain a top pointer.
228 young_gen->to_space()->mangle_unused_area_complete();
229 }
230
231 eden_empty = young_gen->eden_space()->is_empty();
232 if (!eden_empty) {
233 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
234 }
235
236 // Update heap occupancy information which is used as
237 // input to soft ref clearing policy at the next gc.
238 Universe::update_heap_info_at_gc();
239
240 survivors_empty = young_gen->from_space()->is_empty() &&
241 young_gen->to_space()->is_empty();
242 young_gen_empty = eden_empty && survivors_empty;
243
244 PSCardTable* card_table = heap->card_table();
245 MemRegion old_mr = heap->old_gen()->reserved();
246 if (young_gen_empty) {
247 card_table->clear(MemRegion(old_mr.start(), old_mr.end()));
248 } else {
249 card_table->invalidate(MemRegion(old_mr.start(), old_mr.end()));
250 }
251
252 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
253 ClassLoaderDataGraph::purge();
254 MetaspaceUtils::verify_metrics();
255
256 BiasedLocking::restore_marks();
257 heap->prune_scavengable_nmethods();
258
259 #if COMPILER2_OR_JVMCI
260 DerivedPointerTable::update_pointers();
261 #endif
262
263 assert(!ref_processor()->discovery_enabled(), "Should have been disabled earlier");
264
265 // Update time of last GC
266 reset_millis_since_last_gc();
267
268 // Let the size policy know we're done
269 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
270
271 if (UseAdaptiveSizePolicy) {
272
273 log_debug(gc, ergo)("AdaptiveSizeStart: collection: %d ", heap->total_collections());
274 log_trace(gc, ergo)("old_gen_capacity: " SIZE_FORMAT " young_gen_capacity: " SIZE_FORMAT,
275 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
276
277 // Don't check if the size_policy is ready here. Let
278 // the size_policy check that internally.
279 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
280 AdaptiveSizePolicy::should_update_promo_stats(gc_cause)) {
281 // Swap the survivor spaces if from_space is empty. The
282 // resize_young_gen() called below is normally used after
283 // a successful young GC and swapping of survivor spaces;
284 // otherwise, it will fail to resize the young gen with
285 // the current implementation.
286 if (young_gen->from_space()->is_empty()) {
287 young_gen->from_space()->clear(SpaceDecorator::Mangle);
288 young_gen->swap_spaces();
289 }
290
291 // Calculate optimal free space amounts
292 assert(young_gen->max_size() >
293 young_gen->from_space()->capacity_in_bytes() +
294 young_gen->to_space()->capacity_in_bytes(),
295 "Sizes of space in young gen are out of bounds");
296
297 size_t young_live = young_gen->used_in_bytes();
298 size_t eden_live = young_gen->eden_space()->used_in_bytes();
299 size_t old_live = old_gen->used_in_bytes();
300 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
301 size_t max_old_gen_size = old_gen->max_gen_size();
302 size_t max_eden_size = young_gen->max_size() -
303 young_gen->from_space()->capacity_in_bytes() -
304 young_gen->to_space()->capacity_in_bytes();
305
306 // Used for diagnostics
307 size_policy->clear_generation_free_space_flags();
308
309 size_policy->compute_generations_free_space(young_live,
310 eden_live,
311 old_live,
312 cur_eden,
313 max_old_gen_size,
314 max_eden_size,
315 true /* full gc*/);
316
317 size_policy->check_gc_overhead_limit(eden_live,
318 max_old_gen_size,
319 max_eden_size,
320 true /* full gc*/,
321 gc_cause,
322 heap->soft_ref_policy());
323
324 size_policy->decay_supplemental_growth(true /* full gc*/);
325
326 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
327
328 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
329 size_policy->calculated_survivor_size_in_bytes());
330 }
331 log_debug(gc, ergo)("AdaptiveSizeStop: collection: %d ", heap->total_collections());
332 }
333
334 if (UsePerfData) {
335 heap->gc_policy_counters()->update_counters();
336 heap->gc_policy_counters()->update_old_capacity(
337 old_gen->capacity_in_bytes());
338 heap->gc_policy_counters()->update_young_capacity(
339 young_gen->capacity_in_bytes());
340 }
341
342 heap->resize_all_tlabs();
343
344 // We collected the heap, recalculate the metaspace capacity
345 MetaspaceGC::compute_new_size();
346
347 if (log_is_enabled(Debug, gc, heap, exit)) {
348 accumulated_time()->stop();
349 }
350
351 heap->print_heap_change(pre_gc_values);
352
353 // Track memory usage and detect low memory
354 MemoryService::track_memory_usage();
355 heap->update_counters();
356
357 heap->post_full_gc_dump(_gc_timer);
358 }
359
360 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
361 HandleMark hm; // Discard invalid handles created during verification
362 Universe::verify("After GC");
363 }
364
365 // Re-verify object start arrays
366 if (VerifyObjectStartArray &&
367 VerifyAfterGC) {
368 old_gen->verify_object_start_array();
369 }
370
371 if (ZapUnusedHeapArea) {
372 old_gen->object_space()->check_mangled_unused_area_complete();
373 }
374
375 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
376
377 heap->print_heap_after_gc();
378 heap->trace_heap_after_gc(_gc_tracer);
379
380 #ifdef TRACESPINNING
381 ParallelTaskTerminator::print_termination_counts();
382 #endif
383
384 AdaptiveSizePolicyOutput::print(size_policy, heap->total_collections());
385
386 _gc_timer->register_gc_end();
387
388 _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());
389
390 return true;
391 }
392
393 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
394 PSYoungGen* young_gen,
395 PSOldGen* old_gen) {
396 MutableSpace* const eden_space = young_gen->eden_space();
397 assert(!eden_space->is_empty(), "eden must be non-empty");
398 assert(young_gen->virtual_space()->alignment() ==
399 old_gen->virtual_space()->alignment(), "alignments do not match");
400
401 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
402 return false;
403 }
404
405 // Both generations must be completely committed.
406 if (young_gen->virtual_space()->uncommitted_size() != 0) {
407 return false;
408 }
409 if (old_gen->virtual_space()->uncommitted_size() != 0) {
410 return false;
411 }
412
413 // Figure out how much to take from eden. Include the average amount promoted
414 // in the total; otherwise the next young gen GC will simply bail out to a
415 // full GC.
416 const size_t alignment = old_gen->virtual_space()->alignment();
417 const size_t eden_used = eden_space->used_in_bytes();
418 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
419 const size_t absorb_size = align_up(eden_used + promoted, alignment);
420 const size_t eden_capacity = eden_space->capacity_in_bytes();
421
422 if (absorb_size >= eden_capacity) {
423 return false; // Must leave some space in eden.
424 }
425
426 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
427 if (new_young_size < young_gen->min_gen_size()) {
428 return false; // Respect young gen minimum size.
429 }
430
431 log_trace(gc, ergo, heap)(" absorbing " SIZE_FORMAT "K: "
432 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
433 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
434 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
435 absorb_size / K,
436 eden_capacity / K, (eden_capacity - absorb_size) / K,
437 young_gen->from_space()->used_in_bytes() / K,
438 young_gen->to_space()->used_in_bytes() / K,
439 young_gen->capacity_in_bytes() / K, new_young_size / K);
440
441 // Fill the unused part of the old gen.
442 MutableSpace* const old_space = old_gen->object_space();
443 HeapWord* const unused_start = old_space->top();
444 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
445
446 if (unused_words > 0) {
447 if (unused_words < CollectedHeap::min_fill_size()) {
448 return false; // If the old gen cannot be filled, must give up.
449 }
450 CollectedHeap::fill_with_objects(unused_start, unused_words);
451 }
452
453 // Take the live data from eden and set both top and end in the old gen to
454 // eden top. (Need to set end because reset_after_change() mangles the region
455 // from end to virtual_space->high() in debug builds).
456 HeapWord* const new_top = eden_space->top();
457 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
458 absorb_size);
459 young_gen->reset_after_change();
460 old_space->set_top(new_top);
461 old_space->set_end(new_top);
462 old_gen->reset_after_change();
463
464 // Update the object start array for the filler object and the data from eden.
465 ObjectStartArray* const start_array = old_gen->start_array();
466 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
467 start_array->allocate_block(p);
468 }
469
470 // Could update the promoted average here, but it is not typically updated at
471 // full GCs and the value to use is unclear. Something like
472 //
473 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
474
475 size_policy->set_bytes_absorbed_from_eden(absorb_size);
476 return true;
477 }
478
479 void PSMarkSweep::allocate_stacks() {
480 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
481 PSYoungGen* young_gen = heap->young_gen();
482
483 MutableSpace* to_space = young_gen->to_space();
484 _preserved_marks = (PreservedMark*)to_space->top();
485 _preserved_count = 0;
486
487 // We want to calculate the size in bytes first.
488 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
489 // Now divide by the size of a PreservedMark
490 _preserved_count_max /= sizeof(PreservedMark);
491 }
492
493
494 void PSMarkSweep::deallocate_stacks() {
495 _preserved_mark_stack.clear(true);
496 _preserved_oop_stack.clear(true);
497 _marking_stack.clear();
498 _objarray_stack.clear(true);
499 }
500
501 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
502 // Recursively traverse all live objects and mark them
503 GCTraceTime(Info, gc, phases) tm("Phase 1: Mark live objects", _gc_timer);
504
505 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
506
507 // Need to clear claim bits before the tracing starts.
508 ClassLoaderDataGraph::clear_claimed_marks();
509
510 // General strong roots.
511 {
512 ParallelScavengeHeap::ParStrongRootsScope psrs;
513 Universe::oops_do(mark_and_push_closure());
514 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
515 MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations);
516 Threads::oops_do(mark_and_push_closure(), &each_active_code_blob);
517 ObjectSynchronizer::oops_do(mark_and_push_closure());
518 Management::oops_do(mark_and_push_closure());
519 JvmtiExport::oops_do(mark_and_push_closure());
520 SystemDictionary::oops_do(mark_and_push_closure());
521 ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure());
522 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
523 //ScavengableNMethods::scavengable_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
524 AOT_ONLY(AOTLoader::oops_do(mark_and_push_closure());)
525 }
526
527 // Flush marking stack.
528 follow_stack();
529
530 // Process reference objects found during marking
531 {
532 GCTraceTime(Debug, gc, phases) t("Reference Processing", _gc_timer);
533
534 ref_processor()->setup_policy(clear_all_softrefs);
535 ReferenceProcessorPhaseTimes pt(_gc_timer, ref_processor()->max_num_queues());
536 const ReferenceProcessorStats& stats =
537 ref_processor()->process_discovered_references(
538 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, &pt);
539 gc_tracer()->report_gc_reference_stats(stats);
540 pt.print_all_references();
541 }
542
543 // This is the point where the entire marking should have completed.
544 assert(_marking_stack.is_empty(), "Marking should have completed");
545
546 {
547 GCTraceTime(Debug, gc, phases) t("Weak Processing", _gc_timer);
548 WeakProcessor::weak_oops_do(is_alive_closure(), &do_nothing_cl);
549 }
550
551 {
552 GCTraceTime(Debug, gc, phases) t("Class Unloading", _gc_timer);
553
554 // Unload classes and purge the SystemDictionary.
555 bool purged_class = SystemDictionary::do_unloading(_gc_timer);
556
557 // Unload nmethods.
558 CodeCache::do_unloading(is_alive_closure(), purged_class);
559
560 // Prune dead klasses from subklass/sibling/implementor lists.
561 Klass::clean_weak_klass_links(purged_class);
562
563 // Clean JVMCI metadata handles.
564 JVMCI_ONLY(JVMCI::do_unloading(purged_class));
565 }
566
567 _gc_tracer->report_object_count_after_gc(is_alive_closure());
568 }
569
570
571 void PSMarkSweep::mark_sweep_phase2() {
572 GCTraceTime(Info, gc, phases) tm("Phase 2: Compute new object addresses", _gc_timer);
573
574 // Now all live objects are marked, compute the new object addresses.
575
576 // It is not required that we traverse spaces in the same order in
577 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
578 // tracking expects us to do so. See comment under phase4.
579
580 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
581 PSOldGen* old_gen = heap->old_gen();
582
583 // Begin compacting into the old gen
584 PSMarkSweepDecorator::set_destination_decorator_tenured();
585
586 // This will also compact the young gen spaces.
587 old_gen->precompact();
588 }
589
590 void PSMarkSweep::mark_sweep_phase3() {
591 // Adjust the pointers to reflect the new locations
592 GCTraceTime(Info, gc, phases) tm("Phase 3: Adjust pointers", _gc_timer);
593
594 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
595 PSYoungGen* young_gen = heap->young_gen();
596 PSOldGen* old_gen = heap->old_gen();
597
598 // Need to clear claim bits before the tracing starts.
599 ClassLoaderDataGraph::clear_claimed_marks();
600
601 // General strong roots.
602 Universe::oops_do(adjust_pointer_closure());
603 JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles
604 Threads::oops_do(adjust_pointer_closure(), NULL);
605 ObjectSynchronizer::oops_do(adjust_pointer_closure());
606 Management::oops_do(adjust_pointer_closure());
607 JvmtiExport::oops_do(adjust_pointer_closure());
608 SystemDictionary::oops_do(adjust_pointer_closure());
609 ClassLoaderDataGraph::cld_do(adjust_cld_closure());
610
611 // Now adjust pointers in remaining weak roots. (All of which should
612 // have been cleared if they pointed to non-surviving objects.)
613 // Global (weak) JNI handles
614 WeakProcessor::oops_do(adjust_pointer_closure());
615
616 CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations);
617 CodeCache::blobs_do(&adjust_from_blobs);
618 AOT_ONLY(AOTLoader::oops_do(adjust_pointer_closure());)
619
620 ref_processor()->weak_oops_do(adjust_pointer_closure());
621 PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure());
622
623 adjust_marks();
624
625 young_gen->adjust_pointers();
626 old_gen->adjust_pointers();
627 }
628
629 void PSMarkSweep::mark_sweep_phase4() {
630 EventMark m("4 compact heap");
631 GCTraceTime(Info, gc, phases) tm("Phase 4: Move objects", _gc_timer);
632
633 // All pointers are now adjusted, move objects accordingly
634
635 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
636 PSYoungGen* young_gen = heap->young_gen();
637 PSOldGen* old_gen = heap->old_gen();
638
639 old_gen->compact();
640 young_gen->compact();
641 }
642
643 jlong PSMarkSweep::millis_since_last_gc() {
644 // We need a monotonically non-decreasing time in ms but
645 // os::javaTimeMillis() does not guarantee monotonicity.
646 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
647 jlong ret_val = now - _time_of_last_gc;
648 // XXX See note in genCollectedHeap::millis_since_last_gc().
649 if (ret_val < 0) {
650 NOT_PRODUCT(log_warning(gc)("time warp: " JLONG_FORMAT, ret_val);)
651 return 0;
652 }
653 return ret_val;
654 }
655
656 void PSMarkSweep::reset_millis_since_last_gc() {
657 // We need a monotonically non-decreasing time in ms but
658 // os::javaTimeMillis() does not guarantee monotonicity.
659 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
660 }