1 /*
2 * Copyright (c) 2001, 2016, 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 "classfile/stringTable.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "code/codeCache.hpp"
30 #include "gc/parallel/parallelScavengeHeap.hpp"
31 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
32 #include "gc/parallel/psMarkSweep.hpp"
33 #include "gc/parallel/psMarkSweepDecorator.hpp"
34 #include "gc/parallel/psOldGen.hpp"
35 #include "gc/parallel/psScavenge.hpp"
36 #include "gc/parallel/psYoungGen.hpp"
37 #include "gc/serial/markSweep.hpp"
38 #include "gc/shared/gcCause.hpp"
39 #include "gc/shared/gcHeapSummary.hpp"
40 #include "gc/shared/gcId.hpp"
41 #include "gc/shared/gcLocker.inline.hpp"
42 #include "gc/shared/gcTimer.hpp"
43 #include "gc/shared/gcTrace.hpp"
44 #include "gc/shared/gcTraceTime.inline.hpp"
45 #include "gc/shared/isGCActiveMark.hpp"
46 #include "gc/shared/referencePolicy.hpp"
47 #include "gc/shared/referenceProcessor.hpp"
48 #include "gc/shared/spaceDecorator.hpp"
49 #include "logging/log.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "runtime/biasedLocking.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/safepoint.hpp"
54 #include "runtime/vmThread.hpp"
55 #include "services/management.hpp"
56 #include "services/memoryService.hpp"
57 #include "utilities/events.hpp"
58 #include "utilities/stack.inline.hpp"
59
60 elapsedTimer PSMarkSweep::_accumulated_time;
61 jlong PSMarkSweep::_time_of_last_gc = 0;
62 CollectorCounters* PSMarkSweep::_counters = NULL;
63
64 void PSMarkSweep::initialize() {
65 MemRegion mr = ParallelScavengeHeap::heap()->reserved_region();
66 set_ref_processor(new ReferenceProcessor(mr)); // a vanilla ref proc
67 _counters = new CollectorCounters("PSMarkSweep", 1);
68
69 // Dummy counter
70 new CollectorCounters("dummy", 2);
71 }
72
73 // This method contains all heap specific policy for invoking mark sweep.
74 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact
75 // the heap. It will do nothing further. If we need to bail out for policy
76 // reasons, scavenge before full gc, or any other specialized behavior, it
77 // needs to be added here.
78 //
79 // Note that this method should only be called from the vm_thread while
80 // at a safepoint!
81 //
82 // Note that the all_soft_refs_clear flag in the collector policy
83 // may be true because this method can be called without intervening
84 // activity. For example when the heap space is tight and full measure
85 // are being taken to free space.
86
87 void PSMarkSweep::invoke(bool maximum_heap_compaction) {
88 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
89 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
90 assert(!ParallelScavengeHeap::heap()->is_gc_active(), "not reentrant");
91
92 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
93 GCCause::Cause gc_cause = heap->gc_cause();
94 PSAdaptiveSizePolicy* policy = heap->size_policy();
95 IsGCActiveMark mark;
96
97 if (ScavengeBeforeFullGC) {
98 PSScavenge::invoke_no_policy();
99 }
100
101 const bool clear_all_soft_refs =
102 heap->collector_policy()->should_clear_all_soft_refs();
103
104 uint count = maximum_heap_compaction ? 1 : MarkSweepAlwaysCompactCount;
105 UIntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count);
106 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction);
107 }
108
109 // This method contains no policy. You should probably
110 // be calling invoke() instead.
111 bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
112 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
113 assert(ref_processor() != NULL, "Sanity");
114
115 if (GCLocker::check_active_before_gc()) {
116 return false;
117 }
118
119 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
120 GCCause::Cause gc_cause = heap->gc_cause();
121
122 GCIdMark gc_id_mark;
123 _gc_timer->register_gc_start();
124 _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start());
125
126 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
127
128 // The scope of casr should end after code that can change
129 // CollectorPolicy::_should_clear_all_soft_refs.
130 ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy());
131
132 PSYoungGen* young_gen = heap->young_gen();
133 PSOldGen* old_gen = heap->old_gen();
134
135 // Increment the invocation count
136 heap->increment_total_collections(true /* full */);
137
138 // Save information needed to minimize mangling
139 heap->record_gen_tops_before_GC();
140
141 // We need to track unique mark sweep invocations as well.
142 _total_invocations++;
143
144 heap->print_heap_before_gc();
145 heap->trace_heap_before_gc(_gc_tracer);
146
147 // Fill in TLABs
148 heap->accumulate_statistics_all_tlabs();
149 heap->ensure_parsability(true); // retire TLABs
150
151 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
152 HandleMark hm; // Discard invalid handles created during verification
153 Universe::verify("Before GC");
154 }
155
156 // Verify object start arrays
157 if (VerifyObjectStartArray &&
158 VerifyBeforeGC) {
159 old_gen->verify_object_start_array();
160 }
161
162 // Filled in below to track the state of the young gen after the collection.
163 bool eden_empty;
164 bool survivors_empty;
165 bool young_gen_empty;
166
167 {
168 HandleMark hm;
169
170 GCTraceCPUTime tcpu;
171 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause, true);
172
173 heap->pre_full_gc_dump(_gc_timer);
174
175 TraceCollectorStats tcs(counters());
176 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);
177
178 if (TraceOldGenTime) accumulated_time()->start();
179
180 // Let the size policy know we're starting
181 size_policy->major_collection_begin();
182
183 CodeCache::gc_prologue();
184 BiasedLocking::preserve_marks();
185
186 // Capture metadata size before collection for sizing.
187 size_t metadata_prev_used = MetaspaceAux::used_bytes();
188
189 size_t old_gen_prev_used = old_gen->used_in_bytes();
190 size_t young_gen_prev_used = young_gen->used_in_bytes();
191
192 allocate_stacks();
193
194 #if defined(COMPILER2) || INCLUDE_JVMCI
195 DerivedPointerTable::clear();
196 #endif
197
198 ref_processor()->enable_discovery();
199 ref_processor()->setup_policy(clear_all_softrefs);
200
201 mark_sweep_phase1(clear_all_softrefs);
202
203 mark_sweep_phase2();
204
205 #if defined(COMPILER2) || INCLUDE_JVMCI
206 // Don't add any more derived pointers during phase3
207 assert(DerivedPointerTable::is_active(), "Sanity");
208 DerivedPointerTable::set_active(false);
209 #endif
210
211 mark_sweep_phase3();
212
213 mark_sweep_phase4();
214
215 restore_marks();
216
217 deallocate_stacks();
218
219 if (ZapUnusedHeapArea) {
220 // Do a complete mangle (top to end) because the usage for
221 // scratch does not maintain a top pointer.
222 young_gen->to_space()->mangle_unused_area_complete();
223 }
224
225 eden_empty = young_gen->eden_space()->is_empty();
226 if (!eden_empty) {
227 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
228 }
229
230 // Update heap occupancy information which is used as
231 // input to soft ref clearing policy at the next gc.
232 Universe::update_heap_info_at_gc();
233
234 survivors_empty = young_gen->from_space()->is_empty() &&
235 young_gen->to_space()->is_empty();
236 young_gen_empty = eden_empty && survivors_empty;
237
238 ModRefBarrierSet* modBS = barrier_set_cast<ModRefBarrierSet>(heap->barrier_set());
239 MemRegion old_mr = heap->old_gen()->reserved();
240 if (young_gen_empty) {
241 modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
242 } else {
243 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
244 }
245
246 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
247 ClassLoaderDataGraph::purge();
248 MetaspaceAux::verify_metrics();
249
250 BiasedLocking::restore_marks();
251 CodeCache::gc_epilogue();
252 JvmtiExport::gc_epilogue();
253
254 #if defined(COMPILER2) || INCLUDE_JVMCI
255 DerivedPointerTable::update_pointers();
256 #endif
257
258 ref_processor()->enqueue_discovered_references(NULL);
259
260 // Update time of last GC
261 reset_millis_since_last_gc();
262
263 // Let the size policy know we're done
264 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
265
266 if (UseAdaptiveSizePolicy) {
267
268 log_debug(gc, ergo)("AdaptiveSizeStart: collection: %d ", heap->total_collections());
269 log_trace(gc, ergo)("old_gen_capacity: " SIZE_FORMAT " young_gen_capacity: " SIZE_FORMAT,
270 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
271
272 // Don't check if the size_policy is ready here. Let
273 // the size_policy check that internally.
274 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
275 AdaptiveSizePolicy::should_update_promo_stats(gc_cause)) {
276 // Swap the survivor spaces if from_space is empty. The
277 // resize_young_gen() called below is normally used after
278 // a successful young GC and swapping of survivor spaces;
279 // otherwise, it will fail to resize the young gen with
280 // the current implementation.
281 if (young_gen->from_space()->is_empty()) {
282 young_gen->from_space()->clear(SpaceDecorator::Mangle);
283 young_gen->swap_spaces();
284 }
285
286 // Calculate optimal free space amounts
287 assert(young_gen->max_size() >
288 young_gen->from_space()->capacity_in_bytes() +
289 young_gen->to_space()->capacity_in_bytes(),
290 "Sizes of space in young gen are out-of-bounds");
291
292 size_t young_live = young_gen->used_in_bytes();
293 size_t eden_live = young_gen->eden_space()->used_in_bytes();
294 size_t old_live = old_gen->used_in_bytes();
295 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
296 size_t max_old_gen_size = old_gen->max_gen_size();
297 size_t max_eden_size = young_gen->max_size() -
298 young_gen->from_space()->capacity_in_bytes() -
299 young_gen->to_space()->capacity_in_bytes();
300
301 // Used for diagnostics
302 size_policy->clear_generation_free_space_flags();
303
304 size_policy->compute_generations_free_space(young_live,
305 eden_live,
306 old_live,
307 cur_eden,
308 max_old_gen_size,
309 max_eden_size,
310 true /* full gc*/);
311
312 size_policy->check_gc_overhead_limit(young_live,
313 eden_live,
314 max_old_gen_size,
315 max_eden_size,
316 true /* full gc*/,
317 gc_cause,
318 heap->collector_policy());
319
320 size_policy->decay_supplemental_growth(true /* full gc*/);
321
322 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
323
324 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
325 size_policy->calculated_survivor_size_in_bytes());
326 }
327 log_debug(gc, ergo)("AdaptiveSizeStop: collection: %d ", heap->total_collections());
328 }
329
330 if (UsePerfData) {
331 heap->gc_policy_counters()->update_counters();
332 heap->gc_policy_counters()->update_old_capacity(
333 old_gen->capacity_in_bytes());
334 heap->gc_policy_counters()->update_young_capacity(
335 young_gen->capacity_in_bytes());
336 }
337
338 heap->resize_all_tlabs();
339
340 // We collected the heap, recalculate the metaspace capacity
341 MetaspaceGC::compute_new_size();
342
343 if (TraceOldGenTime) accumulated_time()->stop();
344
345 young_gen->print_used_change(young_gen_prev_used);
346 old_gen->print_used_change(old_gen_prev_used);
347 MetaspaceAux::print_metaspace_change(metadata_prev_used);
348
349 // Track memory usage and detect low memory
350 MemoryService::track_memory_usage();
351 heap->update_counters();
352
353 heap->post_full_gc_dump(_gc_timer);
354 }
355
356 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
357 HandleMark hm; // Discard invalid handles created during verification
358 Universe::verify("After GC");
359 }
360
361 // Re-verify object start arrays
362 if (VerifyObjectStartArray &&
363 VerifyAfterGC) {
364 old_gen->verify_object_start_array();
365 }
366
367 if (ZapUnusedHeapArea) {
368 old_gen->object_space()->check_mangled_unused_area_complete();
369 }
370
371 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
372
373 heap->print_heap_after_gc();
374 heap->trace_heap_after_gc(_gc_tracer);
375
376 #ifdef TRACESPINNING
377 ParallelTaskTerminator::print_termination_counts();
378 #endif
379
380 AdaptiveSizePolicyOutput::print(size_policy, heap->total_collections());
381
382 _gc_timer->register_gc_end();
383
384 _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());
385
386 return true;
387 }
388
389 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
390 PSYoungGen* young_gen,
391 PSOldGen* old_gen) {
392 MutableSpace* const eden_space = young_gen->eden_space();
393 assert(!eden_space->is_empty(), "eden must be non-empty");
394 assert(young_gen->virtual_space()->alignment() ==
395 old_gen->virtual_space()->alignment(), "alignments do not match");
396
397 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
398 return false;
399 }
400
401 // Both generations must be completely committed.
402 if (young_gen->virtual_space()->uncommitted_size() != 0) {
403 return false;
404 }
405 if (old_gen->virtual_space()->uncommitted_size() != 0) {
406 return false;
407 }
408
409 // Figure out how much to take from eden. Include the average amount promoted
410 // in the total; otherwise the next young gen GC will simply bail out to a
411 // full GC.
412 const size_t alignment = old_gen->virtual_space()->alignment();
413 const size_t eden_used = eden_space->used_in_bytes();
414 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
415 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
416 const size_t eden_capacity = eden_space->capacity_in_bytes();
417
418 if (absorb_size >= eden_capacity) {
419 return false; // Must leave some space in eden.
420 }
421
422 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
423 if (new_young_size < young_gen->min_gen_size()) {
424 return false; // Respect young gen minimum size.
425 }
426
427 log_trace(heap, ergo)(" absorbing " SIZE_FORMAT "K: "
428 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
429 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
430 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
431 absorb_size / K,
432 eden_capacity / K, (eden_capacity - absorb_size) / K,
433 young_gen->from_space()->used_in_bytes() / K,
434 young_gen->to_space()->used_in_bytes() / K,
435 young_gen->capacity_in_bytes() / K, new_young_size / K);
436
437 // Fill the unused part of the old gen.
438 MutableSpace* const old_space = old_gen->object_space();
439 HeapWord* const unused_start = old_space->top();
440 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
441
442 if (unused_words > 0) {
443 if (unused_words < CollectedHeap::min_fill_size()) {
444 return false; // If the old gen cannot be filled, must give up.
445 }
446 CollectedHeap::fill_with_objects(unused_start, unused_words);
447 }
448
449 // Take the live data from eden and set both top and end in the old gen to
450 // eden top. (Need to set end because reset_after_change() mangles the region
451 // from end to virtual_space->high() in debug builds).
452 HeapWord* const new_top = eden_space->top();
453 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
454 absorb_size);
455 young_gen->reset_after_change();
456 old_space->set_top(new_top);
457 old_space->set_end(new_top);
458 old_gen->reset_after_change();
459
460 // Update the object start array for the filler object and the data from eden.
461 ObjectStartArray* const start_array = old_gen->start_array();
462 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
463 start_array->allocate_block(p);
464 }
465
466 // Could update the promoted average here, but it is not typically updated at
467 // full GCs and the value to use is unclear. Something like
468 //
469 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
470
471 size_policy->set_bytes_absorbed_from_eden(absorb_size);
472 return true;
473 }
474
475 void PSMarkSweep::allocate_stacks() {
476 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
477 PSYoungGen* young_gen = heap->young_gen();
478
479 MutableSpace* to_space = young_gen->to_space();
480 _preserved_marks = (PreservedMark*)to_space->top();
481 _preserved_count = 0;
482
483 // We want to calculate the size in bytes first.
484 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
485 // Now divide by the size of a PreservedMark
486 _preserved_count_max /= sizeof(PreservedMark);
487 }
488
489
490 void PSMarkSweep::deallocate_stacks() {
491 _preserved_mark_stack.clear(true);
492 _preserved_oop_stack.clear(true);
493 _marking_stack.clear();
494 _objarray_stack.clear(true);
495 }
496
497 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
498 // Recursively traverse all live objects and mark them
499 GCTraceTime(Info, gc, phases) tm("Phase 1: Mark live objects", _gc_timer);
500
501 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
502
503 // Need to clear claim bits before the tracing starts.
504 ClassLoaderDataGraph::clear_claimed_marks();
505
506 // General strong roots.
507 {
508 ParallelScavengeHeap::ParStrongRootsScope psrs;
509 Universe::oops_do(mark_and_push_closure());
510 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
511 MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations);
512 Threads::oops_do(mark_and_push_closure(), &each_active_code_blob);
513 ObjectSynchronizer::oops_do(mark_and_push_closure());
514 FlatProfiler::oops_do(mark_and_push_closure());
515 Management::oops_do(mark_and_push_closure());
516 JvmtiExport::oops_do(mark_and_push_closure());
517 SystemDictionary::always_strong_oops_do(mark_and_push_closure());
518 ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure());
519 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
520 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
521 }
522
523 // Flush marking stack.
524 follow_stack();
525
526 // Process reference objects found during marking
527 {
528 GCTraceTime(Debug, gc, phases) t("Reference Processing", _gc_timer);
529
530 ref_processor()->setup_policy(clear_all_softrefs);
531 const ReferenceProcessorStats& stats =
532 ref_processor()->process_discovered_references(
533 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer);
534 gc_tracer()->report_gc_reference_stats(stats);
535 }
536
537 // This is the point where the entire marking should have completed.
538 assert(_marking_stack.is_empty(), "Marking should have completed");
539
540 {
541 GCTraceTime(Debug, gc, phases) t("Class Unloading", _gc_timer);
542
543 // Unload classes and purge the SystemDictionary.
544 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
545
546 // Unload nmethods.
547 CodeCache::do_unloading(is_alive_closure(), purged_class);
548
549 // Prune dead klasses from subklass/sibling/implementor lists.
550 Klass::clean_weak_klass_links(is_alive_closure());
551 }
552
553 {
554 GCTraceTime(Debug, gc, phases) t("Scrub String Table", _gc_timer);
555 // Delete entries for dead interned strings.
556 StringTable::unlink(is_alive_closure());
557 }
558
559 {
560 GCTraceTime(Debug, gc, phases) t("Scrub Symbol Table", _gc_timer);
561 // Clean up unreferenced symbols in symbol table.
562 SymbolTable::unlink();
563 }
564
565 _gc_tracer->report_object_count_after_gc(is_alive_closure());
566 }
567
568
569 void PSMarkSweep::mark_sweep_phase2() {
570 GCTraceTime(Info, gc, phases) tm("Phase 2: Compute new object addresses", _gc_timer);
571
572 // Now all live objects are marked, compute the new object addresses.
573
574 // It is not required that we traverse spaces in the same order in
575 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
576 // tracking expects us to do so. See comment under phase4.
577
578 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
579 PSOldGen* old_gen = heap->old_gen();
580
581 // Begin compacting into the old gen
582 PSMarkSweepDecorator::set_destination_decorator_tenured();
583
584 // This will also compact the young gen spaces.
585 old_gen->precompact();
586 }
587
588 void PSMarkSweep::mark_sweep_phase3() {
589 // Adjust the pointers to reflect the new locations
590 GCTraceTime(Info, gc, phases) tm("Phase 3: Adjust pointers", _gc_timer);
591
592 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
593 PSYoungGen* young_gen = heap->young_gen();
594 PSOldGen* old_gen = heap->old_gen();
595
596 // Need to clear claim bits before the tracing starts.
597 ClassLoaderDataGraph::clear_claimed_marks();
598
599 // General strong roots.
600 Universe::oops_do(adjust_pointer_closure());
601 JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles
602 Threads::oops_do(adjust_pointer_closure(), NULL);
603 ObjectSynchronizer::oops_do(adjust_pointer_closure());
604 FlatProfiler::oops_do(adjust_pointer_closure());
605 Management::oops_do(adjust_pointer_closure());
606 JvmtiExport::oops_do(adjust_pointer_closure());
607 SystemDictionary::oops_do(adjust_pointer_closure());
608 ClassLoaderDataGraph::cld_do(adjust_cld_closure());
609
610 // Now adjust pointers in remaining weak roots. (All of which should
611 // have been cleared if they pointed to non-surviving objects.)
612 // Global (weak) JNI handles
613 JNIHandles::weak_oops_do(adjust_pointer_closure());
614
615 CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations);
616 CodeCache::blobs_do(&adjust_from_blobs);
617 StringTable::oops_do(adjust_pointer_closure());
618 ref_processor()->weak_oops_do(adjust_pointer_closure());
619 PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure());
620
621 adjust_marks();
622
623 young_gen->adjust_pointers();
624 old_gen->adjust_pointers();
625 }
626
627 void PSMarkSweep::mark_sweep_phase4() {
628 EventMark m("4 compact heap");
629 GCTraceTime(Info, gc, phases) tm("Phase 4: Move objects", _gc_timer);
630
631 // All pointers are now adjusted, move objects accordingly
632
633 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
634 PSYoungGen* young_gen = heap->young_gen();
635 PSOldGen* old_gen = heap->old_gen();
636
637 old_gen->compact();
638 young_gen->compact();
639 }
640
641 jlong PSMarkSweep::millis_since_last_gc() {
642 // We need a monotonically non-decreasing time in ms but
643 // os::javaTimeMillis() does not guarantee monotonicity.
644 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
645 jlong ret_val = now - _time_of_last_gc;
646 // XXX See note in genCollectedHeap::millis_since_last_gc().
647 if (ret_val < 0) {
648 NOT_PRODUCT(log_warning(gc)("time warp: " JLONG_FORMAT, ret_val);)
649 return 0;
650 }
651 return ret_val;
652 }
653
654 void PSMarkSweep::reset_millis_since_last_gc() {
655 // We need a monotonically non-decreasing time in ms but
656 // os::javaTimeMillis() does not guarantee monotonicity.
657 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
658 }