1 /*
2 * Copyright (c) 2000, 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 "aot/aotLoader.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "gc/shared/collectedHeap.inline.hpp"
33 #include "gc/shared/collectorCounters.hpp"
34 #include "gc/shared/gcId.hpp"
35 #include "gc/shared/gcLocker.inline.hpp"
36 #include "gc/shared/gcTrace.hpp"
37 #include "gc/shared/gcTraceTime.inline.hpp"
38 #include "gc/shared/genCollectedHeap.hpp"
39 #include "gc/shared/genOopClosures.inline.hpp"
40 #include "gc/shared/generationSpec.hpp"
41 #include "gc/shared/space.hpp"
42 #include "gc/shared/strongRootsScope.hpp"
43 #include "gc/shared/vmGCOperations.hpp"
44 #include "gc/shared/workgroup.hpp"
45 #include "memory/filemap.hpp"
46 #include "memory/resourceArea.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "runtime/biasedLocking.hpp"
49 #include "runtime/fprofiler.hpp"
50 #include "runtime/handles.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/vmThread.hpp"
54 #include "services/management.hpp"
55 #include "services/memoryService.hpp"
56 #include "utilities/macros.hpp"
57 #include "utilities/stack.inline.hpp"
58 #include "utilities/vmError.hpp"
59 #if INCLUDE_ALL_GCS
60 #include "gc/cms/concurrentMarkSweepThread.hpp"
61 #include "gc/cms/vmCMSOperations.hpp"
62 #endif // INCLUDE_ALL_GCS
63
64 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
65
66 // The set of potentially parallel tasks in root scanning.
67 enum GCH_strong_roots_tasks {
68 GCH_PS_Universe_oops_do,
69 GCH_PS_JNIHandles_oops_do,
70 GCH_PS_ObjectSynchronizer_oops_do,
71 GCH_PS_FlatProfiler_oops_do,
72 GCH_PS_Management_oops_do,
73 GCH_PS_SystemDictionary_oops_do,
74 GCH_PS_ClassLoaderDataGraph_oops_do,
75 GCH_PS_jvmti_oops_do,
76 GCH_PS_CodeCache_oops_do,
77 GCH_PS_aot_oops_do,
78 GCH_PS_younger_gens,
79 // Leave this one last.
80 GCH_PS_NumElements
81 };
82
83 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
84 CollectedHeap(),
85 _rem_set(NULL),
86 _gen_policy(policy),
87 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
88 _full_collections_completed(0)
89 {
90 assert(policy != NULL, "Sanity check");
91 if (UseConcMarkSweepGC) {
92 _workers = new WorkGang("GC Thread", ParallelGCThreads,
93 /* are_GC_task_threads */true,
94 /* are_ConcurrentGC_threads */false);
95 _workers->initialize_workers();
96 } else {
97 // Serial GC does not use workers.
98 _workers = NULL;
99 }
100 }
101
102 jint GenCollectedHeap::initialize() {
103 CollectedHeap::pre_initialize();
104
105 // While there are no constraints in the GC code that HeapWordSize
106 // be any particular value, there are multiple other areas in the
107 // system which believe this to be true (e.g. oop->object_size in some
108 // cases incorrectly returns the size in wordSize units rather than
109 // HeapWordSize).
110 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
111
112 // Allocate space for the heap.
113
114 char* heap_address;
115 ReservedSpace heap_rs;
116
117 size_t heap_alignment = collector_policy()->heap_alignment();
118
119 heap_address = allocate(heap_alignment, &heap_rs);
120
121 if (!heap_rs.is_reserved()) {
122 vm_shutdown_during_initialization(
123 "Could not reserve enough space for object heap");
124 return JNI_ENOMEM;
125 }
126
127 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
128
129 _rem_set = collector_policy()->create_rem_set(reserved_region());
130 set_barrier_set(rem_set()->bs());
131
132 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false);
133 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, rem_set());
134 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size());
135
136 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false);
137 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, rem_set());
138 clear_incremental_collection_failed();
139
140 #if INCLUDE_ALL_GCS
141 // If we are running CMS, create the collector responsible
142 // for collecting the CMS generations.
143 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
144 bool success = create_cms_collector();
145 if (!success) return JNI_ENOMEM;
146 }
147 #endif // INCLUDE_ALL_GCS
148
149 return JNI_OK;
150 }
151
152 char* GenCollectedHeap::allocate(size_t alignment,
153 ReservedSpace* heap_rs){
154 // Now figure out the total size.
155 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
156 assert(alignment % pageSize == 0, "Must be");
157
158 GenerationSpec* young_spec = gen_policy()->young_gen_spec();
159 GenerationSpec* old_spec = gen_policy()->old_gen_spec();
160
161 // Check for overflow.
162 size_t total_reserved = young_spec->max_size() + old_spec->max_size();
163 if (total_reserved < young_spec->max_size()) {
164 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
165 "the maximum representable size");
166 }
167 assert(total_reserved % alignment == 0,
168 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
169 SIZE_FORMAT, total_reserved, alignment);
170
171 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
172
173 os::trace_page_sizes("Heap",
174 collector_policy()->min_heap_byte_size(),
175 total_reserved,
176 alignment,
177 heap_rs->base(),
178 heap_rs->size());
179
180 return heap_rs->base();
181 }
182
183 void GenCollectedHeap::post_initialize() {
184 ref_processing_init();
185 assert((_young_gen->kind() == Generation::DefNew) ||
186 (_young_gen->kind() == Generation::ParNew),
187 "Wrong youngest generation type");
188 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
189
190 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep ||
191 _old_gen->kind() == Generation::MarkSweepCompact,
192 "Wrong generation kind");
193
194 _gen_policy->initialize_size_policy(def_new_gen->eden()->capacity(),
195 _old_gen->capacity(),
196 def_new_gen->from()->capacity());
197 _gen_policy->initialize_gc_policy_counters();
198 }
199
200 void GenCollectedHeap::ref_processing_init() {
201 _young_gen->ref_processor_init();
202 _old_gen->ref_processor_init();
203 }
204
205 size_t GenCollectedHeap::capacity() const {
206 return _young_gen->capacity() + _old_gen->capacity();
207 }
208
209 size_t GenCollectedHeap::used() const {
210 return _young_gen->used() + _old_gen->used();
211 }
212
213 void GenCollectedHeap::save_used_regions() {
214 _old_gen->save_used_region();
215 _young_gen->save_used_region();
216 }
217
218 size_t GenCollectedHeap::max_capacity() const {
219 return _young_gen->max_capacity() + _old_gen->max_capacity();
220 }
221
222 // Update the _full_collections_completed counter
223 // at the end of a stop-world full GC.
224 unsigned int GenCollectedHeap::update_full_collections_completed() {
225 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
226 assert(_full_collections_completed <= _total_full_collections,
227 "Can't complete more collections than were started");
228 _full_collections_completed = _total_full_collections;
229 ml.notify_all();
230 return _full_collections_completed;
231 }
232
233 // Update the _full_collections_completed counter, as appropriate,
234 // at the end of a concurrent GC cycle. Note the conditional update
235 // below to allow this method to be called by a concurrent collector
236 // without synchronizing in any manner with the VM thread (which
237 // may already have initiated a STW full collection "concurrently").
238 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
239 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
240 assert((_full_collections_completed <= _total_full_collections) &&
241 (count <= _total_full_collections),
242 "Can't complete more collections than were started");
243 if (count > _full_collections_completed) {
244 _full_collections_completed = count;
245 ml.notify_all();
246 }
247 return _full_collections_completed;
248 }
249
250
251 #ifndef PRODUCT
252 // Override of memory state checking method in CollectedHeap:
253 // Some collectors (CMS for example) can't have badHeapWordVal written
254 // in the first two words of an object. (For instance , in the case of
255 // CMS these words hold state used to synchronize between certain
256 // (concurrent) GC steps and direct allocating mutators.)
257 // The skip_header_HeapWords() method below, allows us to skip
258 // over the requisite number of HeapWord's. Note that (for
259 // generational collectors) this means that those many words are
260 // skipped in each object, irrespective of the generation in which
261 // that object lives. The resultant loss of precision seems to be
262 // harmless and the pain of avoiding that imprecision appears somewhat
263 // higher than we are prepared to pay for such rudimentary debugging
264 // support.
265 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
266 size_t size) {
267 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
268 // We are asked to check a size in HeapWords,
269 // but the memory is mangled in juint words.
270 juint* start = (juint*) (addr + skip_header_HeapWords());
271 juint* end = (juint*) (addr + size);
272 for (juint* slot = start; slot < end; slot += 1) {
273 assert(*slot == badHeapWordVal,
274 "Found non badHeapWordValue in pre-allocation check");
275 }
276 }
277 }
278 #endif
279
280 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
281 bool is_tlab,
282 bool first_only) {
283 HeapWord* res = NULL;
284
285 if (_young_gen->should_allocate(size, is_tlab)) {
286 res = _young_gen->allocate(size, is_tlab);
287 if (res != NULL || first_only) {
288 return res;
289 }
290 }
291
292 if (_old_gen->should_allocate(size, is_tlab)) {
293 res = _old_gen->allocate(size, is_tlab);
294 }
295
296 return res;
297 }
298
299 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
300 bool* gc_overhead_limit_was_exceeded) {
301 return gen_policy()->mem_allocate_work(size,
302 false /* is_tlab */,
303 gc_overhead_limit_was_exceeded);
304 }
305
306 bool GenCollectedHeap::must_clear_all_soft_refs() {
307 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
308 _gc_cause == GCCause::_wb_full_gc;
309 }
310
311 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
312 if (!UseConcMarkSweepGC) {
313 return false;
314 }
315
316 switch (cause) {
317 case GCCause::_gc_locker: return GCLockerInvokesConcurrent;
318 case GCCause::_java_lang_system_gc:
319 case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent;
320 default: return false;
321 }
322 }
323
324 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
325 bool is_tlab, bool run_verification, bool clear_soft_refs,
326 bool restore_marks_for_biased_locking) {
327 FormatBuffer<> title("Collect gen: %s", gen->short_name());
328 GCTraceTime(Trace, gc, phases) t1(title);
329 TraceCollectorStats tcs(gen->counters());
330 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
331
332 gen->stat_record()->invocations++;
333 gen->stat_record()->accumulated_time.start();
334
335 // Must be done anew before each collection because
336 // a previous collection will do mangling and will
337 // change top of some spaces.
338 record_gen_tops_before_GC();
339
340 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
341
342 if (run_verification && VerifyBeforeGC) {
343 HandleMark hm; // Discard invalid handles created during verification
344 Universe::verify("Before GC");
345 }
346 COMPILER2_PRESENT(DerivedPointerTable::clear());
347
348 if (restore_marks_for_biased_locking) {
349 // We perform this mark word preservation work lazily
350 // because it's only at this point that we know whether we
351 // absolutely have to do it; we want to avoid doing it for
352 // scavenge-only collections where it's unnecessary
353 BiasedLocking::preserve_marks();
354 }
355
356 // Do collection work
357 {
358 // Note on ref discovery: For what appear to be historical reasons,
359 // GCH enables and disabled (by enqueing) refs discovery.
360 // In the future this should be moved into the generation's
361 // collect method so that ref discovery and enqueueing concerns
362 // are local to a generation. The collect method could return
363 // an appropriate indication in the case that notification on
364 // the ref lock was needed. This will make the treatment of
365 // weak refs more uniform (and indeed remove such concerns
366 // from GCH). XXX
367
368 HandleMark hm; // Discard invalid handles created during gc
369 save_marks(); // save marks for all gens
370 // We want to discover references, but not process them yet.
371 // This mode is disabled in process_discovered_references if the
372 // generation does some collection work, or in
373 // enqueue_discovered_references if the generation returns
374 // without doing any work.
375 ReferenceProcessor* rp = gen->ref_processor();
376 // If the discovery of ("weak") refs in this generation is
377 // atomic wrt other collectors in this configuration, we
378 // are guaranteed to have empty discovered ref lists.
379 if (rp->discovery_is_atomic()) {
380 rp->enable_discovery();
381 rp->setup_policy(clear_soft_refs);
382 } else {
383 // collect() below will enable discovery as appropriate
384 }
385 gen->collect(full, clear_soft_refs, size, is_tlab);
386 if (!rp->enqueuing_is_done()) {
387 rp->enqueue_discovered_references();
388 } else {
389 rp->set_enqueuing_is_done(false);
390 }
391 rp->verify_no_references_recorded();
392 }
393
394 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
395
396 gen->stat_record()->accumulated_time.stop();
397
398 update_gc_stats(gen, full);
399
400 if (run_verification && VerifyAfterGC) {
401 HandleMark hm; // Discard invalid handles created during verification
402 Universe::verify("After GC");
403 }
404 }
405
406 void GenCollectedHeap::do_collection(bool full,
407 bool clear_all_soft_refs,
408 size_t size,
409 bool is_tlab,
410 GenerationType max_generation) {
411 ResourceMark rm;
412 DEBUG_ONLY(Thread* my_thread = Thread::current();)
413
414 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
415 assert(my_thread->is_VM_thread() ||
416 my_thread->is_ConcurrentGC_thread(),
417 "incorrect thread type capability");
418 assert(Heap_lock->is_locked(),
419 "the requesting thread should have the Heap_lock");
420 guarantee(!is_gc_active(), "collection is not reentrant");
421
422 if (GCLocker::check_active_before_gc()) {
423 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
424 }
425
426 GCIdMarkAndRestore gc_id_mark;
427
428 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
429 collector_policy()->should_clear_all_soft_refs();
430
431 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
432
433 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
434
435 print_heap_before_gc();
436
437 {
438 FlagSetting fl(_is_gc_active, true);
439
440 bool complete = full && (max_generation == OldGen);
441 bool old_collects_young = complete && !ScavengeBeforeFullGC;
442 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
443
444 FormatBuffer<> gc_string("%s", "Pause ");
445 if (do_young_collection) {
446 gc_string.append("Young");
447 } else {
448 gc_string.append("Full");
449 }
450
451 GCTraceCPUTime tcpu;
452 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true);
453
454 gc_prologue(complete);
455 increment_total_collections(complete);
456
457 size_t young_prev_used = _young_gen->used();
458 size_t old_prev_used = _old_gen->used();
459
460 bool run_verification = total_collections() >= VerifyGCStartAt;
461
462 bool prepared_for_verification = false;
463 bool collected_old = false;
464
465 if (do_young_collection) {
466 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
467 prepare_for_verify();
468 prepared_for_verification = true;
469 }
470
471 collect_generation(_young_gen,
472 full,
473 size,
474 is_tlab,
475 run_verification && VerifyGCLevel <= 0,
476 do_clear_all_soft_refs,
477 false);
478
479 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
480 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
481 // Allocation request was met by young GC.
482 size = 0;
483 }
484 }
485
486 bool must_restore_marks_for_biased_locking = false;
487
488 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) {
489 if (!complete) {
490 // The full_collections increment was missed above.
491 increment_total_full_collections();
492 }
493
494 if (!prepared_for_verification && run_verification &&
495 VerifyGCLevel <= 1 && VerifyBeforeGC) {
496 prepare_for_verify();
497 }
498
499 if (do_young_collection) {
500 // We did a young GC. Need a new GC id for the old GC.
501 GCIdMarkAndRestore gc_id_mark;
502 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
503 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
504 } else {
505 // No young GC done. Use the same GC id as was set up earlier in this method.
506 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
507 }
508
509 must_restore_marks_for_biased_locking = true;
510 collected_old = true;
511 }
512
513 // Update "complete" boolean wrt what actually transpired --
514 // for instance, a promotion failure could have led to
515 // a whole heap collection.
516 complete = complete || collected_old;
517
518 print_heap_change(young_prev_used, old_prev_used);
519 MetaspaceAux::print_metaspace_change(metadata_prev_used);
520
521 // Adjust generation sizes.
522 if (collected_old) {
523 _old_gen->compute_new_size();
524 }
525 _young_gen->compute_new_size();
526
527 if (complete) {
528 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
529 ClassLoaderDataGraph::purge();
530 MetaspaceAux::verify_metrics();
531 // Resize the metaspace capacity after full collections
532 MetaspaceGC::compute_new_size();
533 update_full_collections_completed();
534 }
535
536 // Track memory usage and detect low memory after GC finishes
537 MemoryService::track_memory_usage();
538
539 gc_epilogue(complete);
540
541 if (must_restore_marks_for_biased_locking) {
542 BiasedLocking::restore_marks();
543 }
544 }
545
546 print_heap_after_gc();
547
548 #ifdef TRACESPINNING
549 ParallelTaskTerminator::print_termination_counts();
550 #endif
551 }
552
553 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
554 return gen_policy()->satisfy_failed_allocation(size, is_tlab);
555 }
556
557 #ifdef ASSERT
558 class AssertNonScavengableClosure: public OopClosure {
559 public:
560 virtual void do_oop(oop* p) {
561 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
562 "Referent should not be scavengable."); }
563 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
564 };
565 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
566 #endif
567
568 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
569 ScanningOption so,
570 OopClosure* strong_roots,
571 OopClosure* weak_roots,
572 CLDClosure* strong_cld_closure,
573 CLDClosure* weak_cld_closure,
574 CodeBlobToOopClosure* code_roots) {
575 // General roots.
576 assert(Threads::thread_claim_parity() != 0, "must have called prologue code");
577 assert(code_roots != NULL, "code root closure should always be set");
578 // _n_termination for _process_strong_tasks should be set up stream
579 // in a method not running in a GC worker. Otherwise the GC worker
580 // could be trying to change the termination condition while the task
581 // is executing in another GC worker.
582
583 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
584 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
585 }
586
587 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
588 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
589
590 bool is_par = scope->n_threads() > 1;
591 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
592
593 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
594 Universe::oops_do(strong_roots);
595 }
596 // Global (strong) JNI handles
597 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
598 JNIHandles::oops_do(strong_roots);
599 }
600
601 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
602 ObjectSynchronizer::oops_do(strong_roots);
603 }
604 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
605 FlatProfiler::oops_do(strong_roots);
606 }
607 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
608 Management::oops_do(strong_roots);
609 }
610 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
611 JvmtiExport::oops_do(strong_roots);
612 }
613 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) {
614 AOTLoader::oops_do(strong_roots);
615 }
616
617 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
618 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
619 }
620
621 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
622 if (so & SO_ScavengeCodeCache) {
623 assert(code_roots != NULL, "must supply closure for code cache");
624
625 // We only visit parts of the CodeCache when scavenging.
626 CodeCache::scavenge_root_nmethods_do(code_roots);
627 }
628 if (so & SO_AllCodeCache) {
629 assert(code_roots != NULL, "must supply closure for code cache");
630
631 // CMSCollector uses this to do intermediate-strength collections.
632 // We scan the entire code cache, since CodeCache::do_unloading is not called.
633 CodeCache::blobs_do(code_roots);
634 }
635 // Verify that the code cache contents are not subject to
636 // movement by a scavenging collection.
637 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
638 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
639 }
640 }
641
642 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope,
643 OopClosure* root_closure) {
644 assert(root_closure != NULL, "Must be set");
645 // All threads execute the following. A specific chunk of buckets
646 // from the StringTable are the individual tasks.
647 if (scope->n_threads() > 1) {
648 StringTable::possibly_parallel_oops_do(root_closure);
649 } else {
650 StringTable::oops_do(root_closure);
651 }
652 }
653
654 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
655 OopsInGenClosure* root_closure,
656 OopsInGenClosure* old_gen_closure,
657 CLDClosure* cld_closure) {
658 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
659
660 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure,
661 cld_closure, cld_closure, &mark_code_closure);
662 process_string_table_roots(scope, root_closure);
663
664 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
665 root_closure->reset_generation();
666 }
667
668 // When collection is parallel, all threads get to cooperate to do
669 // old generation scanning.
670 old_gen_closure->set_generation(_old_gen);
671 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
672 old_gen_closure->reset_generation();
673
674 _process_strong_tasks->all_tasks_completed(scope->n_threads());
675 }
676
677 void GenCollectedHeap::cms_process_roots(StrongRootsScope* scope,
678 bool young_gen_as_roots,
679 ScanningOption so,
680 bool only_strong_roots,
681 OopsInGenClosure* root_closure,
682 CLDClosure* cld_closure) {
683 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations);
684 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
685 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
686
687 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
688 if (!only_strong_roots) {
689 process_string_table_roots(scope, root_closure);
690 }
691
692 if (young_gen_as_roots &&
693 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
694 root_closure->set_generation(_young_gen);
695 _young_gen->oop_iterate(root_closure);
696 root_closure->reset_generation();
697 }
698
699 _process_strong_tasks->all_tasks_completed(scope->n_threads());
700 }
701
702 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
703 bool is_adjust_phase,
704 ScanningOption so,
705 bool only_strong_roots,
706 OopsInGenClosure* root_closure,
707 CLDClosure* cld_closure) {
708 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
709 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
710 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
711
712 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
713 if (is_adjust_phase) {
714 // We never treat the string table as roots during marking
715 // for the full gc, so we only need to process it during
716 // the adjust phase.
717 process_string_table_roots(scope, root_closure);
718 }
719
720 _process_strong_tasks->all_tasks_completed(scope->n_threads());
721 }
722
723 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
724 JNIHandles::weak_oops_do(root_closure);
725 HeapMonitoring::do_weak_oops(root_closure);
726 _young_gen->ref_processor()->weak_oops_do(root_closure);
727 _old_gen->ref_processor()->weak_oops_do(root_closure);
728 }
729
730 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
731 void GenCollectedHeap:: \
732 oop_since_save_marks_iterate(GenerationType gen, \
733 OopClosureType* cur, \
734 OopClosureType* older) { \
735 if (gen == YoungGen) { \
736 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
737 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
738 } else { \
739 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
740 } \
741 }
742
743 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
744
745 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
746
747 bool GenCollectedHeap::no_allocs_since_save_marks() {
748 return _young_gen->no_allocs_since_save_marks() &&
749 _old_gen->no_allocs_since_save_marks();
750 }
751
752 bool GenCollectedHeap::supports_inline_contig_alloc() const {
753 return _young_gen->supports_inline_contig_alloc();
754 }
755
756 HeapWord* volatile* GenCollectedHeap::top_addr() const {
757 return _young_gen->top_addr();
758 }
759
760 HeapWord** GenCollectedHeap::end_addr() const {
761 return _young_gen->end_addr();
762 }
763
764 // public collection interfaces
765
766 void GenCollectedHeap::collect(GCCause::Cause cause) {
767 if (should_do_concurrent_full_gc(cause)) {
768 #if INCLUDE_ALL_GCS
769 // Mostly concurrent full collection.
770 collect_mostly_concurrent(cause);
771 #else // INCLUDE_ALL_GCS
772 ShouldNotReachHere();
773 #endif // INCLUDE_ALL_GCS
774 } else if (cause == GCCause::_wb_young_gc) {
775 // Young collection for the WhiteBox API.
776 collect(cause, YoungGen);
777 } else {
778 #ifdef ASSERT
779 if (cause == GCCause::_scavenge_alot) {
780 // Young collection only.
781 collect(cause, YoungGen);
782 } else {
783 // Stop-the-world full collection.
784 collect(cause, OldGen);
785 }
786 #else
787 // Stop-the-world full collection.
788 collect(cause, OldGen);
789 #endif
790 }
791 }
792
793 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
794 // The caller doesn't have the Heap_lock
795 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
796 MutexLocker ml(Heap_lock);
797 collect_locked(cause, max_generation);
798 }
799
800 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
801 // The caller has the Heap_lock
802 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
803 collect_locked(cause, OldGen);
804 }
805
806 // this is the private collection interface
807 // The Heap_lock is expected to be held on entry.
808
809 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
810 // Read the GC count while holding the Heap_lock
811 unsigned int gc_count_before = total_collections();
812 unsigned int full_gc_count_before = total_full_collections();
813 {
814 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
815 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
816 cause, max_generation);
817 VMThread::execute(&op);
818 }
819 }
820
821 #if INCLUDE_ALL_GCS
822 bool GenCollectedHeap::create_cms_collector() {
823
824 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
825 "Unexpected generation kinds");
826 // Skip two header words in the block content verification
827 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
828 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type");
829 CMSCollector* collector =
830 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen,
831 _rem_set,
832 _gen_policy->as_concurrent_mark_sweep_policy());
833
834 if (collector == NULL || !collector->completed_initialization()) {
835 if (collector) {
836 delete collector; // Be nice in embedded situation
837 }
838 vm_shutdown_during_initialization("Could not create CMS collector");
839 return false;
840 }
841 return true; // success
842 }
843
844 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
845 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
846
847 MutexLocker ml(Heap_lock);
848 // Read the GC counts while holding the Heap_lock
849 unsigned int full_gc_count_before = total_full_collections();
850 unsigned int gc_count_before = total_collections();
851 {
852 MutexUnlocker mu(Heap_lock);
853 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
854 VMThread::execute(&op);
855 }
856 }
857 #endif // INCLUDE_ALL_GCS
858
859 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
860 do_full_collection(clear_all_soft_refs, OldGen);
861 }
862
863 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
864 GenerationType last_generation) {
865 GenerationType local_last_generation;
866 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
867 gc_cause() == GCCause::_gc_locker) {
868 local_last_generation = YoungGen;
869 } else {
870 local_last_generation = last_generation;
871 }
872
873 do_collection(true, // full
874 clear_all_soft_refs, // clear_all_soft_refs
875 0, // size
876 false, // is_tlab
877 local_last_generation); // last_generation
878 // Hack XXX FIX ME !!!
879 // A scavenge may not have been attempted, or may have
880 // been attempted and failed, because the old gen was too full
881 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker &&
882 incremental_collection_will_fail(false /* don't consult_young */)) {
883 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
884 // This time allow the old gen to be collected as well
885 do_collection(true, // full
886 clear_all_soft_refs, // clear_all_soft_refs
887 0, // size
888 false, // is_tlab
889 OldGen); // last_generation
890 }
891 }
892
893 bool GenCollectedHeap::is_in_young(oop p) {
894 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
895 assert(result == _young_gen->is_in_reserved(p),
896 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
897 return result;
898 }
899
900 // Returns "TRUE" iff "p" points into the committed areas of the heap.
901 bool GenCollectedHeap::is_in(const void* p) const {
902 return _young_gen->is_in(p) || _old_gen->is_in(p);
903 }
904
905 #ifdef ASSERT
906 // Don't implement this by using is_in_young(). This method is used
907 // in some cases to check that is_in_young() is correct.
908 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
909 assert(is_in_reserved(p) || p == NULL,
910 "Does not work if address is non-null and outside of the heap");
911 return p < _young_gen->reserved().end() && p != NULL;
912 }
913 #endif
914
915 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) {
916 NoHeaderExtendedOopClosure no_header_cl(cl);
917 oop_iterate(&no_header_cl);
918 }
919
920 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
921 _young_gen->oop_iterate(cl);
922 _old_gen->oop_iterate(cl);
923 }
924
925 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
926 _young_gen->object_iterate(cl);
927 _old_gen->object_iterate(cl);
928 }
929
930 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
931 _young_gen->safe_object_iterate(cl);
932 _old_gen->safe_object_iterate(cl);
933 }
934
935 Space* GenCollectedHeap::space_containing(const void* addr) const {
936 Space* res = _young_gen->space_containing(addr);
937 if (res != NULL) {
938 return res;
939 }
940 res = _old_gen->space_containing(addr);
941 assert(res != NULL, "Could not find containing space");
942 return res;
943 }
944
945 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
946 assert(is_in_reserved(addr), "block_start of address outside of heap");
947 if (_young_gen->is_in_reserved(addr)) {
948 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
949 return _young_gen->block_start(addr);
950 }
951
952 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
953 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
954 return _old_gen->block_start(addr);
955 }
956
957 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
958 assert(is_in_reserved(addr), "block_size of address outside of heap");
959 if (_young_gen->is_in_reserved(addr)) {
960 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
961 return _young_gen->block_size(addr);
962 }
963
964 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
965 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
966 return _old_gen->block_size(addr);
967 }
968
969 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
970 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
971 assert(block_start(addr) == addr, "addr must be a block start");
972 if (_young_gen->is_in_reserved(addr)) {
973 return _young_gen->block_is_obj(addr);
974 }
975
976 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
977 return _old_gen->block_is_obj(addr);
978 }
979
980 bool GenCollectedHeap::supports_tlab_allocation() const {
981 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
982 return _young_gen->supports_tlab_allocation();
983 }
984
985 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
986 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
987 if (_young_gen->supports_tlab_allocation()) {
988 return _young_gen->tlab_capacity();
989 }
990 return 0;
991 }
992
993 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
994 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
995 if (_young_gen->supports_tlab_allocation()) {
996 return _young_gen->tlab_used();
997 }
998 return 0;
999 }
1000
1001 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1002 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1003 if (_young_gen->supports_tlab_allocation()) {
1004 return _young_gen->unsafe_max_tlab_alloc();
1005 }
1006 return 0;
1007 }
1008
1009 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1010 bool gc_overhead_limit_was_exceeded;
1011 return gen_policy()->mem_allocate_work(size /* size */,
1012 true /* is_tlab */,
1013 &gc_overhead_limit_was_exceeded);
1014 }
1015
1016 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1017 // from the list headed by "*prev_ptr".
1018 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1019 bool first = true;
1020 size_t min_size = 0; // "first" makes this conceptually infinite.
1021 ScratchBlock **smallest_ptr, *smallest;
1022 ScratchBlock *cur = *prev_ptr;
1023 while (cur) {
1024 assert(*prev_ptr == cur, "just checking");
1025 if (first || cur->num_words < min_size) {
1026 smallest_ptr = prev_ptr;
1027 smallest = cur;
1028 min_size = smallest->num_words;
1029 first = false;
1030 }
1031 prev_ptr = &cur->next;
1032 cur = cur->next;
1033 }
1034 smallest = *smallest_ptr;
1035 *smallest_ptr = smallest->next;
1036 return smallest;
1037 }
1038
1039 // Sort the scratch block list headed by res into decreasing size order,
1040 // and set "res" to the result.
1041 static void sort_scratch_list(ScratchBlock*& list) {
1042 ScratchBlock* sorted = NULL;
1043 ScratchBlock* unsorted = list;
1044 while (unsorted) {
1045 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1046 smallest->next = sorted;
1047 sorted = smallest;
1048 }
1049 list = sorted;
1050 }
1051
1052 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1053 size_t max_alloc_words) {
1054 ScratchBlock* res = NULL;
1055 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1056 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1057 sort_scratch_list(res);
1058 return res;
1059 }
1060
1061 void GenCollectedHeap::release_scratch() {
1062 _young_gen->reset_scratch();
1063 _old_gen->reset_scratch();
1064 }
1065
1066 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1067 void do_generation(Generation* gen) {
1068 gen->prepare_for_verify();
1069 }
1070 };
1071
1072 void GenCollectedHeap::prepare_for_verify() {
1073 ensure_parsability(false); // no need to retire TLABs
1074 GenPrepareForVerifyClosure blk;
1075 generation_iterate(&blk, false);
1076 }
1077
1078 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1079 bool old_to_young) {
1080 if (old_to_young) {
1081 cl->do_generation(_old_gen);
1082 cl->do_generation(_young_gen);
1083 } else {
1084 cl->do_generation(_young_gen);
1085 cl->do_generation(_old_gen);
1086 }
1087 }
1088
1089 bool GenCollectedHeap::is_maximal_no_gc() const {
1090 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1091 }
1092
1093 void GenCollectedHeap::save_marks() {
1094 _young_gen->save_marks();
1095 _old_gen->save_marks();
1096 }
1097
1098 GenCollectedHeap* GenCollectedHeap::heap() {
1099 CollectedHeap* heap = Universe::heap();
1100 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1101 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap");
1102 return (GenCollectedHeap*)heap;
1103 }
1104
1105 void GenCollectedHeap::prepare_for_compaction() {
1106 // Start by compacting into same gen.
1107 CompactPoint cp(_old_gen);
1108 _old_gen->prepare_for_compaction(&cp);
1109 _young_gen->prepare_for_compaction(&cp);
1110 }
1111
1112 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1113 log_debug(gc, verify)("%s", _old_gen->name());
1114 _old_gen->verify();
1115
1116 log_debug(gc, verify)("%s", _old_gen->name());
1117 _young_gen->verify();
1118
1119 log_debug(gc, verify)("RemSet");
1120 rem_set()->verify();
1121 }
1122
1123 void GenCollectedHeap::print_on(outputStream* st) const {
1124 _young_gen->print_on(st);
1125 _old_gen->print_on(st);
1126 MetaspaceAux::print_on(st);
1127 }
1128
1129 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1130 if (workers() != NULL) {
1131 workers()->threads_do(tc);
1132 }
1133 #if INCLUDE_ALL_GCS
1134 if (UseConcMarkSweepGC) {
1135 ConcurrentMarkSweepThread::threads_do(tc);
1136 }
1137 #endif // INCLUDE_ALL_GCS
1138 }
1139
1140 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1141 #if INCLUDE_ALL_GCS
1142 if (UseConcMarkSweepGC) {
1143 workers()->print_worker_threads_on(st);
1144 ConcurrentMarkSweepThread::print_all_on(st);
1145 }
1146 #endif // INCLUDE_ALL_GCS
1147 }
1148
1149 void GenCollectedHeap::print_on_error(outputStream* st) const {
1150 this->CollectedHeap::print_on_error(st);
1151
1152 #if INCLUDE_ALL_GCS
1153 if (UseConcMarkSweepGC) {
1154 st->cr();
1155 CMSCollector::print_on_error(st);
1156 }
1157 #endif // INCLUDE_ALL_GCS
1158 }
1159
1160 void GenCollectedHeap::print_tracing_info() const {
1161 if (TraceYoungGenTime) {
1162 _young_gen->print_summary_info();
1163 }
1164 if (TraceOldGenTime) {
1165 _old_gen->print_summary_info();
1166 }
1167 }
1168
1169 void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const {
1170 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1171 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K);
1172 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1173 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K);
1174 }
1175
1176 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1177 private:
1178 bool _full;
1179 public:
1180 void do_generation(Generation* gen) {
1181 gen->gc_prologue(_full);
1182 }
1183 GenGCPrologueClosure(bool full) : _full(full) {};
1184 };
1185
1186 void GenCollectedHeap::gc_prologue(bool full) {
1187 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1188
1189 always_do_update_barrier = false;
1190 // Fill TLAB's and such
1191 CollectedHeap::accumulate_statistics_all_tlabs();
1192 ensure_parsability(true); // retire TLABs
1193
1194 // Walk generations
1195 GenGCPrologueClosure blk(full);
1196 generation_iterate(&blk, false); // not old-to-young.
1197 };
1198
1199 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1200 private:
1201 bool _full;
1202 public:
1203 void do_generation(Generation* gen) {
1204 gen->gc_epilogue(_full);
1205 }
1206 GenGCEpilogueClosure(bool full) : _full(full) {};
1207 };
1208
1209 void GenCollectedHeap::gc_epilogue(bool full) {
1210 #if defined(COMPILER2) || INCLUDE_JVMCI
1211 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1212 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1213 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1214 #endif /* COMPILER2 || INCLUDE_JVMCI */
1215
1216 resize_all_tlabs();
1217
1218 GenGCEpilogueClosure blk(full);
1219 generation_iterate(&blk, false); // not old-to-young.
1220
1221 if (!CleanChunkPoolAsync) {
1222 Chunk::clean_chunk_pool();
1223 }
1224
1225 MetaspaceCounters::update_performance_counters();
1226 CompressedClassSpaceCounters::update_performance_counters();
1227
1228 always_do_update_barrier = UseConcMarkSweepGC;
1229 };
1230
1231 #ifndef PRODUCT
1232 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1233 private:
1234 public:
1235 void do_generation(Generation* gen) {
1236 gen->record_spaces_top();
1237 }
1238 };
1239
1240 void GenCollectedHeap::record_gen_tops_before_GC() {
1241 if (ZapUnusedHeapArea) {
1242 GenGCSaveTopsBeforeGCClosure blk;
1243 generation_iterate(&blk, false); // not old-to-young.
1244 }
1245 }
1246 #endif // not PRODUCT
1247
1248 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1249 public:
1250 void do_generation(Generation* gen) {
1251 gen->ensure_parsability();
1252 }
1253 };
1254
1255 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1256 CollectedHeap::ensure_parsability(retire_tlabs);
1257 GenEnsureParsabilityClosure ep_cl;
1258 generation_iterate(&ep_cl, false);
1259 }
1260
1261 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1262 oop obj,
1263 size_t obj_size) {
1264 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1265 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1266 HeapWord* result = NULL;
1267
1268 result = old_gen->expand_and_allocate(obj_size, false);
1269
1270 if (result != NULL) {
1271 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1272 }
1273 return oop(result);
1274 }
1275
1276 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1277 jlong _time; // in ms
1278 jlong _now; // in ms
1279
1280 public:
1281 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1282
1283 jlong time() { return _time; }
1284
1285 void do_generation(Generation* gen) {
1286 _time = MIN2(_time, gen->time_of_last_gc(_now));
1287 }
1288 };
1289
1290 jlong GenCollectedHeap::millis_since_last_gc() {
1291 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1292 // provided the underlying platform provides such a time source
1293 // (and it is bug free). So we still have to guard against getting
1294 // back a time later than 'now'.
1295 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1296 GenTimeOfLastGCClosure tolgc_cl(now);
1297 // iterate over generations getting the oldest
1298 // time that a generation was collected
1299 generation_iterate(&tolgc_cl, false);
1300
1301 jlong retVal = now - tolgc_cl.time();
1302 if (retVal < 0) {
1303 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1304 ". returning zero instead.", retVal);
1305 return 0;
1306 }
1307 return retVal;
1308 }
1309
1310 void GenCollectedHeap::stop() {
1311 #if INCLUDE_ALL_GCS
1312 if (UseConcMarkSweepGC) {
1313 ConcurrentMarkSweepThread::cmst()->stop();
1314 }
1315 #endif
1316 }