Thu, 14 Mar 2013 09:37:38 +0100
6733980: par compact - TraceGen1Time always shows 0.0000 seconds
Summary: Use the correct collector to retrieve accumulated gen1 trace time
Reviewed-by: johnc, jmasa
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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23 */
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "code/codeCache.hpp"
29 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
31 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
32 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
33 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
34 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
35 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
36 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"
37 #include "gc_implementation/shared/isGCActiveMark.hpp"
38 #include "gc_implementation/shared/markSweep.hpp"
39 #include "gc_implementation/shared/spaceDecorator.hpp"
40 #include "gc_interface/gcCause.hpp"
41 #include "memory/gcLocker.inline.hpp"
42 #include "memory/referencePolicy.hpp"
43 #include "memory/referenceProcessor.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "runtime/biasedLocking.hpp"
46 #include "runtime/fprofiler.hpp"
47 #include "runtime/safepoint.hpp"
48 #include "runtime/vmThread.hpp"
49 #include "services/management.hpp"
50 #include "services/memoryService.hpp"
51 #include "utilities/events.hpp"
52 #include "utilities/stack.inline.hpp"
54 elapsedTimer PSMarkSweep::_accumulated_time;
55 jlong PSMarkSweep::_time_of_last_gc = 0;
56 CollectorCounters* PSMarkSweep::_counters = NULL;
58 void PSMarkSweep::initialize() {
59 MemRegion mr = Universe::heap()->reserved_region();
60 _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc
61 _counters = new CollectorCounters("PSMarkSweep", 1);
62 }
64 // This method contains all heap specific policy for invoking mark sweep.
65 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact
66 // the heap. It will do nothing further. If we need to bail out for policy
67 // reasons, scavenge before full gc, or any other specialized behavior, it
68 // needs to be added here.
69 //
70 // Note that this method should only be called from the vm_thread while
71 // at a safepoint!
72 //
73 // Note that the all_soft_refs_clear flag in the collector policy
74 // may be true because this method can be called without intervening
75 // activity. For example when the heap space is tight and full measure
76 // are being taken to free space.
78 void PSMarkSweep::invoke(bool maximum_heap_compaction) {
79 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
80 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
81 assert(!Universe::heap()->is_gc_active(), "not reentrant");
83 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
84 GCCause::Cause gc_cause = heap->gc_cause();
85 PSAdaptiveSizePolicy* policy = heap->size_policy();
86 IsGCActiveMark mark;
88 if (ScavengeBeforeFullGC) {
89 PSScavenge::invoke_no_policy();
90 }
92 const bool clear_all_soft_refs =
93 heap->collector_policy()->should_clear_all_soft_refs();
95 int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount;
96 IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count);
97 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction);
98 }
100 // This method contains no policy. You should probably
101 // be calling invoke() instead.
102 bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
103 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
104 assert(ref_processor() != NULL, "Sanity");
106 if (GC_locker::check_active_before_gc()) {
107 return false;
108 }
110 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
111 GCCause::Cause gc_cause = heap->gc_cause();
112 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
113 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
115 // The scope of casr should end after code that can change
116 // CollectorPolicy::_should_clear_all_soft_refs.
117 ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy());
119 PSYoungGen* young_gen = heap->young_gen();
120 PSOldGen* old_gen = heap->old_gen();
122 // Increment the invocation count
123 heap->increment_total_collections(true /* full */);
125 // Save information needed to minimize mangling
126 heap->record_gen_tops_before_GC();
128 // We need to track unique mark sweep invocations as well.
129 _total_invocations++;
131 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
133 heap->print_heap_before_gc();
135 // Fill in TLABs
136 heap->accumulate_statistics_all_tlabs();
137 heap->ensure_parsability(true); // retire TLABs
139 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
140 HandleMark hm; // Discard invalid handles created during verification
141 gclog_or_tty->print(" VerifyBeforeGC:");
142 Universe::verify();
143 }
145 // Verify object start arrays
146 if (VerifyObjectStartArray &&
147 VerifyBeforeGC) {
148 old_gen->verify_object_start_array();
149 }
151 heap->pre_full_gc_dump();
153 // Filled in below to track the state of the young gen after the collection.
154 bool eden_empty;
155 bool survivors_empty;
156 bool young_gen_empty;
158 {
159 HandleMark hm;
161 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
162 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
163 TraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, gclog_or_tty);
164 TraceCollectorStats tcs(counters());
165 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);
167 if (TraceGen1Time) accumulated_time()->start();
169 // Let the size policy know we're starting
170 size_policy->major_collection_begin();
172 CodeCache::gc_prologue();
173 Threads::gc_prologue();
174 BiasedLocking::preserve_marks();
176 // Capture heap size before collection for printing.
177 size_t prev_used = heap->used();
179 // Capture metadata size before collection for sizing.
180 size_t metadata_prev_used = MetaspaceAux::used_in_bytes();
182 // For PrintGCDetails
183 size_t old_gen_prev_used = old_gen->used_in_bytes();
184 size_t young_gen_prev_used = young_gen->used_in_bytes();
186 allocate_stacks();
188 COMPILER2_PRESENT(DerivedPointerTable::clear());
190 ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
191 ref_processor()->setup_policy(clear_all_softrefs);
193 mark_sweep_phase1(clear_all_softrefs);
195 mark_sweep_phase2();
197 // Don't add any more derived pointers during phase3
198 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
199 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
201 mark_sweep_phase3();
203 mark_sweep_phase4();
205 restore_marks();
207 deallocate_stacks();
209 if (ZapUnusedHeapArea) {
210 // Do a complete mangle (top to end) because the usage for
211 // scratch does not maintain a top pointer.
212 young_gen->to_space()->mangle_unused_area_complete();
213 }
215 eden_empty = young_gen->eden_space()->is_empty();
216 if (!eden_empty) {
217 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
218 }
220 // Update heap occupancy information which is used as
221 // input to soft ref clearing policy at the next gc.
222 Universe::update_heap_info_at_gc();
224 survivors_empty = young_gen->from_space()->is_empty() &&
225 young_gen->to_space()->is_empty();
226 young_gen_empty = eden_empty && survivors_empty;
228 BarrierSet* bs = heap->barrier_set();
229 if (bs->is_a(BarrierSet::ModRef)) {
230 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
231 MemRegion old_mr = heap->old_gen()->reserved();
232 if (young_gen_empty) {
233 modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
234 } else {
235 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
236 }
237 }
239 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
240 ClassLoaderDataGraph::purge();
242 BiasedLocking::restore_marks();
243 Threads::gc_epilogue();
244 CodeCache::gc_epilogue();
245 JvmtiExport::gc_epilogue();
247 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
249 ref_processor()->enqueue_discovered_references(NULL);
251 // Update time of last GC
252 reset_millis_since_last_gc();
254 // Let the size policy know we're done
255 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
257 if (UseAdaptiveSizePolicy) {
259 if (PrintAdaptiveSizePolicy) {
260 gclog_or_tty->print("AdaptiveSizeStart: ");
261 gclog_or_tty->stamp();
262 gclog_or_tty->print_cr(" collection: %d ",
263 heap->total_collections());
264 if (Verbose) {
265 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d",
266 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
267 }
268 }
270 // Don't check if the size_policy is ready here. Let
271 // the size_policy check that internally.
272 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
273 ((gc_cause != GCCause::_java_lang_system_gc) ||
274 UseAdaptiveSizePolicyWithSystemGC)) {
275 // Calculate optimal free space amounts
276 assert(young_gen->max_size() >
277 young_gen->from_space()->capacity_in_bytes() +
278 young_gen->to_space()->capacity_in_bytes(),
279 "Sizes of space in young gen are out-of-bounds");
280 size_t max_eden_size = young_gen->max_size() -
281 young_gen->from_space()->capacity_in_bytes() -
282 young_gen->to_space()->capacity_in_bytes();
283 size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
284 young_gen->eden_space()->used_in_bytes(),
285 old_gen->used_in_bytes(),
286 young_gen->eden_space()->capacity_in_bytes(),
287 old_gen->max_gen_size(),
288 max_eden_size,
289 true /* full gc*/,
290 gc_cause,
291 heap->collector_policy());
293 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
295 // Don't resize the young generation at an major collection. A
296 // desired young generation size may have been calculated but
297 // resizing the young generation complicates the code because the
298 // resizing of the old generation may have moved the boundary
299 // between the young generation and the old generation. Let the
300 // young generation resizing happen at the minor collections.
301 }
302 if (PrintAdaptiveSizePolicy) {
303 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
304 heap->total_collections());
305 }
306 }
308 if (UsePerfData) {
309 heap->gc_policy_counters()->update_counters();
310 heap->gc_policy_counters()->update_old_capacity(
311 old_gen->capacity_in_bytes());
312 heap->gc_policy_counters()->update_young_capacity(
313 young_gen->capacity_in_bytes());
314 }
316 heap->resize_all_tlabs();
318 // We collected the heap, recalculate the metaspace capacity
319 MetaspaceGC::compute_new_size();
321 if (TraceGen1Time) accumulated_time()->stop();
323 if (PrintGC) {
324 if (PrintGCDetails) {
325 // Don't print a GC timestamp here. This is after the GC so
326 // would be confusing.
327 young_gen->print_used_change(young_gen_prev_used);
328 old_gen->print_used_change(old_gen_prev_used);
329 }
330 heap->print_heap_change(prev_used);
331 if (PrintGCDetails) {
332 MetaspaceAux::print_metaspace_change(metadata_prev_used);
333 }
334 }
336 // Track memory usage and detect low memory
337 MemoryService::track_memory_usage();
338 heap->update_counters();
339 }
341 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
342 HandleMark hm; // Discard invalid handles created during verification
343 gclog_or_tty->print(" VerifyAfterGC:");
344 Universe::verify();
345 }
347 // Re-verify object start arrays
348 if (VerifyObjectStartArray &&
349 VerifyAfterGC) {
350 old_gen->verify_object_start_array();
351 }
353 if (ZapUnusedHeapArea) {
354 old_gen->object_space()->check_mangled_unused_area_complete();
355 }
357 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
359 heap->print_heap_after_gc();
361 heap->post_full_gc_dump();
363 #ifdef TRACESPINNING
364 ParallelTaskTerminator::print_termination_counts();
365 #endif
367 return true;
368 }
370 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
371 PSYoungGen* young_gen,
372 PSOldGen* old_gen) {
373 MutableSpace* const eden_space = young_gen->eden_space();
374 assert(!eden_space->is_empty(), "eden must be non-empty");
375 assert(young_gen->virtual_space()->alignment() ==
376 old_gen->virtual_space()->alignment(), "alignments do not match");
378 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
379 return false;
380 }
382 // Both generations must be completely committed.
383 if (young_gen->virtual_space()->uncommitted_size() != 0) {
384 return false;
385 }
386 if (old_gen->virtual_space()->uncommitted_size() != 0) {
387 return false;
388 }
390 // Figure out how much to take from eden. Include the average amount promoted
391 // in the total; otherwise the next young gen GC will simply bail out to a
392 // full GC.
393 const size_t alignment = old_gen->virtual_space()->alignment();
394 const size_t eden_used = eden_space->used_in_bytes();
395 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
396 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
397 const size_t eden_capacity = eden_space->capacity_in_bytes();
399 if (absorb_size >= eden_capacity) {
400 return false; // Must leave some space in eden.
401 }
403 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
404 if (new_young_size < young_gen->min_gen_size()) {
405 return false; // Respect young gen minimum size.
406 }
408 if (TraceAdaptiveGCBoundary && Verbose) {
409 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
410 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
411 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
412 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
413 absorb_size / K,
414 eden_capacity / K, (eden_capacity - absorb_size) / K,
415 young_gen->from_space()->used_in_bytes() / K,
416 young_gen->to_space()->used_in_bytes() / K,
417 young_gen->capacity_in_bytes() / K, new_young_size / K);
418 }
420 // Fill the unused part of the old gen.
421 MutableSpace* const old_space = old_gen->object_space();
422 HeapWord* const unused_start = old_space->top();
423 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
425 if (unused_words > 0) {
426 if (unused_words < CollectedHeap::min_fill_size()) {
427 return false; // If the old gen cannot be filled, must give up.
428 }
429 CollectedHeap::fill_with_objects(unused_start, unused_words);
430 }
432 // Take the live data from eden and set both top and end in the old gen to
433 // eden top. (Need to set end because reset_after_change() mangles the region
434 // from end to virtual_space->high() in debug builds).
435 HeapWord* const new_top = eden_space->top();
436 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
437 absorb_size);
438 young_gen->reset_after_change();
439 old_space->set_top(new_top);
440 old_space->set_end(new_top);
441 old_gen->reset_after_change();
443 // Update the object start array for the filler object and the data from eden.
444 ObjectStartArray* const start_array = old_gen->start_array();
445 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
446 start_array->allocate_block(p);
447 }
449 // Could update the promoted average here, but it is not typically updated at
450 // full GCs and the value to use is unclear. Something like
451 //
452 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
454 size_policy->set_bytes_absorbed_from_eden(absorb_size);
455 return true;
456 }
458 void PSMarkSweep::allocate_stacks() {
459 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
460 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
462 PSYoungGen* young_gen = heap->young_gen();
464 MutableSpace* to_space = young_gen->to_space();
465 _preserved_marks = (PreservedMark*)to_space->top();
466 _preserved_count = 0;
468 // We want to calculate the size in bytes first.
469 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
470 // Now divide by the size of a PreservedMark
471 _preserved_count_max /= sizeof(PreservedMark);
472 }
475 void PSMarkSweep::deallocate_stacks() {
476 _preserved_mark_stack.clear(true);
477 _preserved_oop_stack.clear(true);
478 _marking_stack.clear();
479 _objarray_stack.clear(true);
480 }
482 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
483 // Recursively traverse all live objects and mark them
484 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty);
485 trace(" 1");
487 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
488 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
490 // Need to clear claim bits before the tracing starts.
491 ClassLoaderDataGraph::clear_claimed_marks();
493 // General strong roots.
494 {
495 ParallelScavengeHeap::ParStrongRootsScope psrs;
496 Universe::oops_do(mark_and_push_closure());
497 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
498 CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure());
499 CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true);
500 Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob);
501 ObjectSynchronizer::oops_do(mark_and_push_closure());
502 FlatProfiler::oops_do(mark_and_push_closure());
503 Management::oops_do(mark_and_push_closure());
504 JvmtiExport::oops_do(mark_and_push_closure());
505 SystemDictionary::always_strong_oops_do(mark_and_push_closure());
506 ClassLoaderDataGraph::always_strong_oops_do(mark_and_push_closure(), follow_klass_closure(), true);
507 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
508 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
509 }
511 // Flush marking stack.
512 follow_stack();
514 // Process reference objects found during marking
515 {
516 ref_processor()->setup_policy(clear_all_softrefs);
517 ref_processor()->process_discovered_references(
518 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL);
519 }
521 // Follow system dictionary roots and unload classes
522 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
524 // Follow code cache roots
525 CodeCache::do_unloading(is_alive_closure(), purged_class);
526 follow_stack(); // Flush marking stack
528 // Update subklass/sibling/implementor links of live klasses
529 Klass::clean_weak_klass_links(&is_alive);
530 assert(_marking_stack.is_empty(), "just drained");
532 // Visit interned string tables and delete unmarked oops
533 StringTable::unlink(is_alive_closure());
534 // Clean up unreferenced symbols in symbol table.
535 SymbolTable::unlink();
537 assert(_marking_stack.is_empty(), "stack should be empty by now");
538 }
541 void PSMarkSweep::mark_sweep_phase2() {
542 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty);
543 trace("2");
545 // Now all live objects are marked, compute the new object addresses.
547 // It is not required that we traverse spaces in the same order in
548 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
549 // tracking expects us to do so. See comment under phase4.
551 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
552 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
554 PSOldGen* old_gen = heap->old_gen();
556 // Begin compacting into the old gen
557 PSMarkSweepDecorator::set_destination_decorator_tenured();
559 // This will also compact the young gen spaces.
560 old_gen->precompact();
561 }
563 // This should be moved to the shared markSweep code!
564 class PSAlwaysTrueClosure: public BoolObjectClosure {
565 public:
566 void do_object(oop p) { ShouldNotReachHere(); }
567 bool do_object_b(oop p) { return true; }
568 };
569 static PSAlwaysTrueClosure always_true;
571 void PSMarkSweep::mark_sweep_phase3() {
572 // Adjust the pointers to reflect the new locations
573 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty);
574 trace("3");
576 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
577 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
579 PSYoungGen* young_gen = heap->young_gen();
580 PSOldGen* old_gen = heap->old_gen();
582 // Need to clear claim bits before the tracing starts.
583 ClassLoaderDataGraph::clear_claimed_marks();
585 // General strong roots.
586 Universe::oops_do(adjust_root_pointer_closure());
587 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
588 CLDToOopClosure adjust_from_cld(adjust_root_pointer_closure());
589 Threads::oops_do(adjust_root_pointer_closure(), &adjust_from_cld, NULL);
590 ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
591 FlatProfiler::oops_do(adjust_root_pointer_closure());
592 Management::oops_do(adjust_root_pointer_closure());
593 JvmtiExport::oops_do(adjust_root_pointer_closure());
594 // SO_AllClasses
595 SystemDictionary::oops_do(adjust_root_pointer_closure());
596 ClassLoaderDataGraph::oops_do(adjust_root_pointer_closure(), adjust_klass_closure(), true);
597 //CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure());
599 // Now adjust pointers in remaining weak roots. (All of which should
600 // have been cleared if they pointed to non-surviving objects.)
601 // Global (weak) JNI handles
602 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
604 CodeCache::oops_do(adjust_pointer_closure());
605 StringTable::oops_do(adjust_root_pointer_closure());
606 ref_processor()->weak_oops_do(adjust_root_pointer_closure());
607 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure());
609 adjust_marks();
611 young_gen->adjust_pointers();
612 old_gen->adjust_pointers();
613 }
615 void PSMarkSweep::mark_sweep_phase4() {
616 EventMark m("4 compact heap");
617 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty);
618 trace("4");
620 // All pointers are now adjusted, move objects accordingly
622 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
623 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
625 PSYoungGen* young_gen = heap->young_gen();
626 PSOldGen* old_gen = heap->old_gen();
628 old_gen->compact();
629 young_gen->compact();
630 }
632 jlong PSMarkSweep::millis_since_last_gc() {
633 // We need a monotonically non-deccreasing time in ms but
634 // os::javaTimeMillis() does not guarantee monotonicity.
635 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
636 jlong ret_val = now - _time_of_last_gc;
637 // XXX See note in genCollectedHeap::millis_since_last_gc().
638 if (ret_val < 0) {
639 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);)
640 return 0;
641 }
642 return ret_val;
643 }
645 void PSMarkSweep::reset_millis_since_last_gc() {
646 // We need a monotonically non-deccreasing time in ms but
647 // os::javaTimeMillis() does not guarantee monotonicity.
648 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
649 }