1 /*
2 * Copyright (c) 2001, 2012, 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/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"
53
54 elapsedTimer PSMarkSweep::_accumulated_time;
55 jlong PSMarkSweep::_time_of_last_gc = 0;
56 CollectorCounters* PSMarkSweep::_counters = NULL;
57
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 }
63
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.
77
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");
82
83 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
84 GCCause::Cause gc_cause = heap->gc_cause();
85 PSAdaptiveSizePolicy* policy = heap->size_policy();
86 IsGCActiveMark mark;
87
88 if (ScavengeBeforeFullGC) {
89 PSScavenge::invoke_no_policy();
90 }
91
92 const bool clear_all_soft_refs =
93 heap->collector_policy()->should_clear_all_soft_refs();
94
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 }
99
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");
105
106 if (GC_locker::check_active_before_gc()) {
107 return false;
108 }
109
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();
114
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());
118
119 PSYoungGen* young_gen = heap->young_gen();
120 PSOldGen* old_gen = heap->old_gen();
121
122 // Increment the invocation count
123 heap->increment_total_collections(true /* full */);
124
125 // Save information needed to minimize mangling
126 heap->record_gen_tops_before_GC();
127
128 // We need to track unique mark sweep invocations as well.
129 _total_invocations++;
130
131 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
132
133 heap->print_heap_before_gc();
134
135 // Fill in TLABs
136 heap->accumulate_statistics_all_tlabs();
137 heap->ensure_parsability(true); // retire TLABs
138
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 }
144
145 // Verify object start arrays
146 if (VerifyObjectStartArray &&
147 VerifyBeforeGC) {
148 old_gen->verify_object_start_array();
149 }
150
151 heap->pre_full_gc_dump();
152
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;
157
158 {
159 HandleMark hm;
160
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);
166
167 if (TraceGen1Time) accumulated_time()->start();
168
169 // Let the size policy know we're starting
170 size_policy->major_collection_begin();
171
172 CodeCache::gc_prologue();
173 Threads::gc_prologue();
174 BiasedLocking::preserve_marks();
175
176 // Capture heap size before collection for printing.
177 size_t prev_used = heap->used();
178
179 // Capture metadata size before collection for sizing.
180 size_t metadata_prev_used = MetaspaceAux::used_in_bytes();
181
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();
185
186 allocate_stacks();
187
188 COMPILER2_PRESENT(DerivedPointerTable::clear());
189
190 ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
191 ref_processor()->setup_policy(clear_all_softrefs);
192
193 mark_sweep_phase1(clear_all_softrefs);
194
195 mark_sweep_phase2();
196
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));
200
201 mark_sweep_phase3();
202
203 mark_sweep_phase4();
204
205 restore_marks();
206
207 deallocate_stacks();
208
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 }
214
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 }
219
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();
223
224 survivors_empty = young_gen->from_space()->is_empty() &&
225 young_gen->to_space()->is_empty();
226 young_gen_empty = eden_empty && survivors_empty;
227
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 }
238
239 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
240 ClassLoaderDataGraph::purge();
241
242 BiasedLocking::restore_marks();
243 Threads::gc_epilogue();
244 CodeCache::gc_epilogue();
245 JvmtiExport::gc_epilogue();
246
247 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
248
249 ref_processor()->enqueue_discovered_references(NULL);
250
251 // Update time of last GC
252 reset_millis_since_last_gc();
253
254 // Let the size policy know we're done
255 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
256
257 if (UseAdaptiveSizePolicy) {
258
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 }
269
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());
292
293 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
294
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 }
307
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 }
315
316 heap->resize_all_tlabs();
317
318 // We collected the heap, recalculate the metaspace capacity
319 MetaspaceGC::compute_new_size();
320
321 if (TraceGen1Time) accumulated_time()->stop();
322
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 }
335
336 // Track memory usage and detect low memory
337 MemoryService::track_memory_usage();
338 heap->update_counters();
339 }
340
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 }
346
347 // Re-verify object start arrays
348 if (VerifyObjectStartArray &&
349 VerifyAfterGC) {
350 old_gen->verify_object_start_array();
351 }
352
353 if (ZapUnusedHeapArea) {
354 old_gen->object_space()->check_mangled_unused_area_complete();
355 }
356
357 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
358
359 heap->print_heap_after_gc();
360
361 heap->post_full_gc_dump();
362
363 #ifdef TRACESPINNING
364 ParallelTaskTerminator::print_termination_counts();
365 #endif
366
367 return true;
368 }
369
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");
377
378 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
379 return false;
380 }
381
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 }
389
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();
398
399 if (absorb_size >= eden_capacity) {
400 return false; // Must leave some space in eden.
401 }
402
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 }
407
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 }
419
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);
424
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 }
431
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();
442
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 }
448
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.
453
454 size_policy->set_bytes_absorbed_from_eden(absorb_size);
455 return true;
456 }
457
458 void PSMarkSweep::allocate_stacks() {
459 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
460 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
461
462 PSYoungGen* young_gen = heap->young_gen();
463
464 MutableSpace* to_space = young_gen->to_space();
465 _preserved_marks = (PreservedMark*)to_space->top();
466 _preserved_count = 0;
467
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 }
473
474
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 }
481
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");
486
487 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
488 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
489
490 // Need to clear claim bits before the tracing starts.
491 ClassLoaderDataGraph::clear_claimed_marks();
492
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 CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true);
499 Threads::oops_do(mark_and_push_closure(), &each_active_code_blob);
500 ObjectSynchronizer::oops_do(mark_and_push_closure());
501 FlatProfiler::oops_do(mark_and_push_closure());
502 Management::oops_do(mark_and_push_closure());
503 JvmtiExport::oops_do(mark_and_push_closure());
504 SystemDictionary::always_strong_oops_do(mark_and_push_closure());
505 ClassLoaderDataGraph::always_strong_oops_do(mark_and_push_closure(), follow_klass_closure(), true);
506 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
507 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
508 }
509
510 // Flush marking stack.
511 follow_stack();
512
513 // Process reference objects found during marking
514 {
515 ref_processor()->setup_policy(clear_all_softrefs);
516 ref_processor()->process_discovered_references(
517 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL);
518 }
519
520 // Follow system dictionary roots and unload classes
521 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
522
523 // Follow code cache roots
524 CodeCache::do_unloading(is_alive_closure(), purged_class);
525 follow_stack(); // Flush marking stack
526
527 // Update subklass/sibling/implementor links of live klasses
528 Klass::clean_weak_klass_links(&is_alive);
529 assert(_marking_stack.is_empty(), "just drained");
530
531 // Visit interned string tables and delete unmarked oops
532 StringTable::unlink(is_alive_closure());
533 // Clean up unreferenced symbols in symbol table.
534 SymbolTable::unlink();
535
536 assert(_marking_stack.is_empty(), "stack should be empty by now");
537 }
538
539
540 void PSMarkSweep::mark_sweep_phase2() {
541 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty);
542 trace("2");
543
544 // Now all live objects are marked, compute the new object addresses.
545
546 // It is not required that we traverse spaces in the same order in
547 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
548 // tracking expects us to do so. See comment under phase4.
549
550 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
551 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
552
553 PSOldGen* old_gen = heap->old_gen();
554
555 // Begin compacting into the old gen
556 PSMarkSweepDecorator::set_destination_decorator_tenured();
557
558 // This will also compact the young gen spaces.
559 old_gen->precompact();
560 }
561
562 // This should be moved to the shared markSweep code!
563 class PSAlwaysTrueClosure: public BoolObjectClosure {
564 public:
565 void do_object(oop p) { ShouldNotReachHere(); }
566 bool do_object_b(oop p) { return true; }
567 };
568 static PSAlwaysTrueClosure always_true;
569
570 void PSMarkSweep::mark_sweep_phase3() {
571 // Adjust the pointers to reflect the new locations
572 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty);
573 trace("3");
574
575 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
576 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
577
578 PSYoungGen* young_gen = heap->young_gen();
579 PSOldGen* old_gen = heap->old_gen();
580
581 // Need to clear claim bits before the tracing starts.
582 ClassLoaderDataGraph::clear_claimed_marks();
583
584 // General strong roots.
585 Universe::oops_do(adjust_root_pointer_closure());
586 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
587 Threads::oops_do(adjust_root_pointer_closure(), NULL);
588 ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
589 FlatProfiler::oops_do(adjust_root_pointer_closure());
590 Management::oops_do(adjust_root_pointer_closure());
591 JvmtiExport::oops_do(adjust_root_pointer_closure());
592 // SO_AllClasses
593 SystemDictionary::oops_do(adjust_root_pointer_closure());
594 ClassLoaderDataGraph::oops_do(adjust_root_pointer_closure(), adjust_klass_closure(), true);
595 //CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure());
596
597 // Now adjust pointers in remaining weak roots. (All of which should
598 // have been cleared if they pointed to non-surviving objects.)
599 // Global (weak) JNI handles
600 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
601
602 CodeCache::oops_do(adjust_pointer_closure());
603 StringTable::oops_do(adjust_root_pointer_closure());
604 ref_processor()->weak_oops_do(adjust_root_pointer_closure());
605 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure());
606
607 adjust_marks();
608
609 young_gen->adjust_pointers();
610 old_gen->adjust_pointers();
611 }
612
613 void PSMarkSweep::mark_sweep_phase4() {
614 EventMark m("4 compact heap");
615 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty);
616 trace("4");
617
618 // All pointers are now adjusted, move objects accordingly
619
620 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
621 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
622
623 PSYoungGen* young_gen = heap->young_gen();
624 PSOldGen* old_gen = heap->old_gen();
625
626 old_gen->compact();
627 young_gen->compact();
628 }
629
630 jlong PSMarkSweep::millis_since_last_gc() {
631 // We need a monotonically non-deccreasing time in ms but
632 // os::javaTimeMillis() does not guarantee monotonicity.
633 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
634 jlong ret_val = now - _time_of_last_gc;
635 // XXX See note in genCollectedHeap::millis_since_last_gc().
636 if (ret_val < 0) {
637 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);)
638 return 0;
639 }
640 return ret_val;
641 }
642
643 void PSMarkSweep::reset_millis_since_last_gc() {
644 // We need a monotonically non-deccreasing time in ms but
645 // os::javaTimeMillis() does not guarantee monotonicity.
646 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
647 }