121 vm_shutdown_during_initialization(
122 "Could not reserve enough space for object heap");
123 return JNI_ENOMEM;
124 }
125
126 _reserved = MemRegion((HeapWord*)heap_rs.base(),
127 (HeapWord*)(heap_rs.base() + heap_rs.size()));
128
129 // It is important to do this in a way such that concurrent readers can't
130 // temporarily think something is in the heap. (Seen this happen in asserts.)
131 _reserved.set_word_size(0);
132 _reserved.set_start((HeapWord*)heap_rs.base());
133 size_t actual_heap_size = heap_rs.size();
134 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
135
136 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
137 set_barrier_set(rem_set()->bs());
138
139 _gch = this;
140
141 for (i = 0; i < _n_gens; i++) {
142 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(), false, false);
143 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
144 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
145 }
146 clear_incremental_collection_failed();
147
148 #if INCLUDE_ALL_GCS
149 // If we are running CMS, create the collector responsible
150 // for collecting the CMS generations.
151 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
152 bool success = create_cms_collector();
153 if (!success) return JNI_ENOMEM;
154 }
155 #endif // INCLUDE_ALL_GCS
156
157 return JNI_OK;
158 }
159
160
161 char* GenCollectedHeap::allocate(size_t alignment,
162 size_t* _total_reserved,
163 int* _n_covered_regions,
164 ReservedSpace* heap_rs){
165 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
166 "the maximum representable size";
167
168 // Now figure out the total size.
169 size_t total_reserved = 0;
170 int n_covered_regions = 0;
171 const size_t pageSize = UseLargePages ?
172 os::large_page_size() : os::vm_page_size();
173
174 assert(alignment % pageSize == 0, "Must be");
175
176 for (int i = 0; i < _n_gens; i++) {
177 total_reserved += _gen_specs[i]->max_size();
178 if (total_reserved < _gen_specs[i]->max_size()) {
179 vm_exit_during_initialization(overflow_msg);
180 }
181 n_covered_regions += _gen_specs[i]->n_covered_regions();
182 }
183 assert(total_reserved % alignment == 0,
184 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
185 SIZE_FORMAT, total_reserved, alignment));
186
187 // Needed until the cardtable is fixed to have the right number
188 // of covered regions.
189 n_covered_regions += 2;
190
191 *_total_reserved = total_reserved;
192 *_n_covered_regions = n_covered_regions;
193
194 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
195 return heap_rs->base();
196 }
197
198
199 void GenCollectedHeap::post_initialize() {
200 SharedHeap::post_initialize();
201 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
202 guarantee(policy->is_generation_policy(), "Illegal policy type");
203 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
204 assert(def_new_gen->kind() == Generation::DefNew ||
205 def_new_gen->kind() == Generation::ParNew,
206 "Wrong generation kind");
207
208 Generation* old_gen = get_gen(1);
209 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
210 old_gen->kind() == Generation::MarkSweepCompact,
211 "Wrong generation kind");
212
213 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
214 old_gen->capacity(),
215 def_new_gen->from()->capacity());
216 policy->initialize_gc_policy_counters();
217 }
218
219 void GenCollectedHeap::ref_processing_init() {
220 SharedHeap::ref_processing_init();
221 for (int i = 0; i < _n_gens; i++) {
222 _gens[i]->ref_processor_init();
223 }
224 }
225
226 size_t GenCollectedHeap::capacity() const {
227 size_t res = 0;
228 for (int i = 0; i < _n_gens; i++) {
229 res += _gens[i]->capacity();
230 }
231 return res;
232 }
233
234 size_t GenCollectedHeap::used() const {
235 size_t res = 0;
236 for (int i = 0; i < _n_gens; i++) {
237 res += _gens[i]->used();
238 }
239 return res;
240 }
241
242 // Save the "used_region" for generations level and lower.
243 void GenCollectedHeap::save_used_regions(int level) {
244 assert(level < _n_gens, "Illegal level parameter");
245 for (int i = level; i >= 0; i--) {
246 _gens[i]->save_used_region();
247 }
248 }
249
250 size_t GenCollectedHeap::max_capacity() const {
251 size_t res = 0;
252 for (int i = 0; i < _n_gens; i++) {
253 res += _gens[i]->max_capacity();
254 }
255 return res;
256 }
257
258 // Update the _full_collections_completed counter
259 // at the end of a stop-world full GC.
260 unsigned int GenCollectedHeap::update_full_collections_completed() {
261 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
262 assert(_full_collections_completed <= _total_full_collections,
263 "Can't complete more collections than were started");
264 _full_collections_completed = _total_full_collections;
265 ml.notify_all();
266 return _full_collections_completed;
267 }
268
269 // Update the _full_collections_completed counter, as appropriate,
270 // at the end of a concurrent GC cycle. Note the conditional update
271 // below to allow this method to be called by a concurrent collector
272 // without synchronizing in any manner with the VM thread (which
273 // may already have initiated a STW full collection "concurrently").
274 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
275 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
299 // higher than we are prepared to pay for such rudimentary debugging
300 // support.
301 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
302 size_t size) {
303 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
304 // We are asked to check a size in HeapWords,
305 // but the memory is mangled in juint words.
306 juint* start = (juint*) (addr + skip_header_HeapWords());
307 juint* end = (juint*) (addr + size);
308 for (juint* slot = start; slot < end; slot += 1) {
309 assert(*slot == badHeapWordVal,
310 "Found non badHeapWordValue in pre-allocation check");
311 }
312 }
313 }
314 #endif
315
316 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
317 bool is_tlab,
318 bool first_only) {
319 HeapWord* res;
320 for (int i = 0; i < _n_gens; i++) {
321 if (_gens[i]->should_allocate(size, is_tlab)) {
322 res = _gens[i]->allocate(size, is_tlab);
323 if (res != NULL) return res;
324 else if (first_only) break;
325 }
326 }
327 // Otherwise...
328 return NULL;
329 }
330
331 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
332 bool* gc_overhead_limit_was_exceeded) {
333 return collector_policy()->mem_allocate_work(size,
334 false /* is_tlab */,
335 gc_overhead_limit_was_exceeded);
336 }
337
338 bool GenCollectedHeap::must_clear_all_soft_refs() {
339 return _gc_cause == GCCause::_last_ditch_collection;
340 }
341
342 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
343 return UseConcMarkSweepGC &&
344 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
345 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
346 }
347
348 void GenCollectedHeap::do_collection(bool full,
349 bool clear_all_soft_refs,
350 size_t size,
351 bool is_tlab,
352 int max_level) {
353 bool prepared_for_verification = false;
354 ResourceMark rm;
355 DEBUG_ONLY(Thread* my_thread = Thread::current();)
356
357 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
358 assert(my_thread->is_VM_thread() ||
359 my_thread->is_ConcurrentGC_thread(),
360 "incorrect thread type capability");
361 assert(Heap_lock->is_locked(),
362 "the requesting thread should have the Heap_lock");
363 guarantee(!is_gc_active(), "collection is not reentrant");
364 assert(max_level < n_gens(), "sanity check");
365
366 if (GC_locker::check_active_before_gc()) {
367 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
368 }
369
370 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
371 collector_policy()->should_clear_all_soft_refs();
372
373 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
374
375 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
376
377 print_heap_before_gc();
378
379 {
380 FlagSetting fl(_is_gc_active, true);
381
382 bool complete = full && (max_level == (n_gens()-1));
383 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
384 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
385 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
386 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
387 // so we can assume here that the next GC id is what we want.
388 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
389
390 gc_prologue(complete);
391 increment_total_collections(complete);
392
393 size_t gch_prev_used = used();
394
395 int starting_level = 0;
396 if (full) {
397 // Search for the oldest generation which will collect all younger
398 // generations, and start collection loop there.
399 for (int i = max_level; i >= 0; i--) {
400 if (_gens[i]->full_collects_younger_generations()) {
401 starting_level = i;
402 break;
403 }
404 }
405 }
406
407 bool must_restore_marks_for_biased_locking = false;
408
409 int max_level_collected = starting_level;
410 for (int i = starting_level; i <= max_level; i++) {
411 if (_gens[i]->should_collect(full, size, is_tlab)) {
412 if (i == n_gens() - 1) { // a major collection is to happen
413 if (!complete) {
414 // The full_collections increment was missed above.
415 increment_total_full_collections();
416 }
417 pre_full_gc_dump(NULL); // do any pre full gc dumps
418 }
419 // Timer for individual generations. Last argument is false: no CR
420 // FIXME: We should try to start the timing earlier to cover more of the GC pause
421 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
422 // so we can assume here that the next GC id is what we want.
423 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL, GCId::peek());
424 TraceCollectorStats tcs(_gens[i]->counters());
425 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
426
427 size_t prev_used = _gens[i]->used();
428 _gens[i]->stat_record()->invocations++;
429 _gens[i]->stat_record()->accumulated_time.start();
430
431 // Must be done anew before each collection because
432 // a previous collection will do mangling and will
433 // change top of some spaces.
434 record_gen_tops_before_GC();
435
436 if (PrintGC && Verbose) {
437 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
438 i,
439 _gens[i]->stat_record()->invocations,
440 size*HeapWordSize);
441 }
442
443 if (VerifyBeforeGC && i >= VerifyGCLevel &&
444 total_collections() >= VerifyGCStartAt) {
445 HandleMark hm; // Discard invalid handles created during verification
446 if (!prepared_for_verification) {
447 prepare_for_verify();
448 prepared_for_verification = true;
449 }
450 Universe::verify(" VerifyBeforeGC:");
451 }
452 COMPILER2_PRESENT(DerivedPointerTable::clear());
453
454 if (!must_restore_marks_for_biased_locking &&
455 _gens[i]->performs_in_place_marking()) {
456 // We perform this mark word preservation work lazily
457 // because it's only at this point that we know whether we
458 // absolutely have to do it; we want to avoid doing it for
459 // scavenge-only collections where it's unnecessary
460 must_restore_marks_for_biased_locking = true;
461 BiasedLocking::preserve_marks();
462 }
463
464 // Do collection work
465 {
466 // Note on ref discovery: For what appear to be historical reasons,
467 // GCH enables and disabled (by enqueing) refs discovery.
468 // In the future this should be moved into the generation's
469 // collect method so that ref discovery and enqueueing concerns
470 // are local to a generation. The collect method could return
471 // an appropriate indication in the case that notification on
472 // the ref lock was needed. This will make the treatment of
473 // weak refs more uniform (and indeed remove such concerns
474 // from GCH). XXX
475
476 HandleMark hm; // Discard invalid handles created during gc
477 save_marks(); // save marks for all gens
478 // We want to discover references, but not process them yet.
479 // This mode is disabled in process_discovered_references if the
480 // generation does some collection work, or in
481 // enqueue_discovered_references if the generation returns
482 // without doing any work.
483 ReferenceProcessor* rp = _gens[i]->ref_processor();
484 // If the discovery of ("weak") refs in this generation is
485 // atomic wrt other collectors in this configuration, we
486 // are guaranteed to have empty discovered ref lists.
487 if (rp->discovery_is_atomic()) {
488 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
489 rp->setup_policy(do_clear_all_soft_refs);
490 } else {
491 // collect() below will enable discovery as appropriate
492 }
493 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
494 if (!rp->enqueuing_is_done()) {
495 rp->enqueue_discovered_references();
496 } else {
497 rp->set_enqueuing_is_done(false);
498 }
499 rp->verify_no_references_recorded();
500 }
501 max_level_collected = i;
502
503 // Determine if allocation request was met.
504 if (size > 0) {
505 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
506 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
507 size = 0;
508 }
509 }
510 }
511
512 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
513
514 _gens[i]->stat_record()->accumulated_time.stop();
515
516 update_gc_stats(i, full);
517
518 if (VerifyAfterGC && i >= VerifyGCLevel &&
519 total_collections() >= VerifyGCStartAt) {
520 HandleMark hm; // Discard invalid handles created during verification
521 Universe::verify(" VerifyAfterGC:");
522 }
523
524 if (PrintGCDetails) {
525 gclog_or_tty->print(":");
526 _gens[i]->print_heap_change(prev_used);
527 }
528 }
529 }
530
531 // Update "complete" boolean wrt what actually transpired --
532 // for instance, a promotion failure could have led to
533 // a whole heap collection.
534 complete = complete || (max_level_collected == n_gens() - 1);
535
536 if (complete) { // We did a "major" collection
537 // FIXME: See comment at pre_full_gc_dump call
538 post_full_gc_dump(NULL); // do any post full gc dumps
539 }
540
541 if (PrintGCDetails) {
542 print_heap_change(gch_prev_used);
543
544 // Print metaspace info for full GC with PrintGCDetails flag.
545 if (complete) {
546 MetaspaceAux::print_metaspace_change(metadata_prev_used);
547 }
548 }
549
550 for (int j = max_level_collected; j >= 0; j -= 1) {
551 // Adjust generation sizes.
552 _gens[j]->compute_new_size();
553 }
554
555 if (complete) {
556 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
557 ClassLoaderDataGraph::purge();
558 MetaspaceAux::verify_metrics();
559 // Resize the metaspace capacity after full collections
560 MetaspaceGC::compute_new_size();
561 update_full_collections_completed();
562 }
563
564 // Track memory usage and detect low memory after GC finishes
565 MemoryService::track_memory_usage();
566
567 gc_epilogue(complete);
568
569 if (must_restore_marks_for_biased_locking) {
570 BiasedLocking::restore_marks();
571 }
572 }
573
590 void GenCollectedHeap::
591 gen_process_roots(int level,
592 bool younger_gens_as_roots,
593 bool activate_scope,
594 SharedHeap::ScanningOption so,
595 OopsInGenClosure* not_older_gens,
596 OopsInGenClosure* weak_roots,
597 OopsInGenClosure* older_gens,
598 CLDClosure* cld_closure,
599 CLDClosure* weak_cld_closure,
600 CodeBlobClosure* code_closure) {
601
602 // General roots.
603 SharedHeap::process_roots(activate_scope, so,
604 not_older_gens, weak_roots,
605 cld_closure, weak_cld_closure,
606 code_closure);
607
608 if (younger_gens_as_roots) {
609 if (!_gen_process_roots_tasks->is_task_claimed(GCH_PS_younger_gens)) {
610 for (int i = 0; i < level; i++) {
611 not_older_gens->set_generation(_gens[i]);
612 _gens[i]->oop_iterate(not_older_gens);
613 }
614 not_older_gens->reset_generation();
615 }
616 }
617 // When collection is parallel, all threads get to cooperate to do
618 // older-gen scanning.
619 for (int i = level+1; i < _n_gens; i++) {
620 older_gens->set_generation(_gens[i]);
621 rem_set()->younger_refs_iterate(_gens[i], older_gens);
622 older_gens->reset_generation();
623 }
624
625 _gen_process_roots_tasks->all_tasks_completed();
626 }
627
628 void GenCollectedHeap::
629 gen_process_roots(int level,
630 bool younger_gens_as_roots,
631 bool activate_scope,
632 SharedHeap::ScanningOption so,
633 bool only_strong_roots,
634 OopsInGenClosure* not_older_gens,
635 OopsInGenClosure* older_gens,
636 CLDClosure* cld_closure) {
637
638 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
639
640 bool is_moving_collection = false;
641 if (level == 0 || is_adjust_phase) {
642 // young collections are always moving
643 is_moving_collection = true;
644 }
645
646 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
647 CodeBlobClosure* code_closure = &mark_code_closure;
648
649 gen_process_roots(level,
650 younger_gens_as_roots,
651 activate_scope, so,
652 not_older_gens, only_strong_roots ? NULL : not_older_gens,
653 older_gens,
654 cld_closure, only_strong_roots ? NULL : cld_closure,
655 code_closure);
656
657 }
658
659 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
660 SharedHeap::process_weak_roots(root_closure);
661 // "Local" "weak" refs
662 for (int i = 0; i < _n_gens; i++) {
663 _gens[i]->ref_processor()->weak_oops_do(root_closure);
664 }
665 }
666
667 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
668 void GenCollectedHeap:: \
669 oop_since_save_marks_iterate(int level, \
670 OopClosureType* cur, \
671 OopClosureType* older) { \
672 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
673 for (int i = level+1; i < n_gens(); i++) { \
674 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
675 } \
676 }
677
678 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
679
680 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
681
682 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
683 for (int i = level; i < _n_gens; i++) {
684 if (!_gens[i]->no_allocs_since_save_marks()) return false;
685 }
686 return true;
687 }
688
689 bool GenCollectedHeap::supports_inline_contig_alloc() const {
690 return _gens[0]->supports_inline_contig_alloc();
691 }
692
693 HeapWord** GenCollectedHeap::top_addr() const {
694 return _gens[0]->top_addr();
695 }
696
697 HeapWord** GenCollectedHeap::end_addr() const {
698 return _gens[0]->end_addr();
699 }
700
701 // public collection interfaces
702
703 void GenCollectedHeap::collect(GCCause::Cause cause) {
704 if (should_do_concurrent_full_gc(cause)) {
705 #if INCLUDE_ALL_GCS
706 // mostly concurrent full collection
707 collect_mostly_concurrent(cause);
708 #else // INCLUDE_ALL_GCS
709 ShouldNotReachHere();
710 #endif // INCLUDE_ALL_GCS
711 } else {
712 #ifdef ASSERT
713 if (cause == GCCause::_scavenge_alot) {
714 // minor collection only
715 collect(cause, 0);
716 } else {
717 // Stop-the-world full collection
718 collect(cause, n_gens() - 1);
738 }
739
740 // this is the private collection interface
741 // The Heap_lock is expected to be held on entry.
742
743 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
744 // Read the GC count while holding the Heap_lock
745 unsigned int gc_count_before = total_collections();
746 unsigned int full_gc_count_before = total_full_collections();
747 {
748 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
749 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
750 cause, max_level);
751 VMThread::execute(&op);
752 }
753 }
754
755 #if INCLUDE_ALL_GCS
756 bool GenCollectedHeap::create_cms_collector() {
757
758 assert(_gens[1]->kind() == Generation::ConcurrentMarkSweep,
759 "Unexpected generation kinds");
760 // Skip two header words in the block content verification
761 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
762 CMSCollector* collector = new CMSCollector(
763 (ConcurrentMarkSweepGeneration*)_gens[1],
764 _rem_set->as_CardTableRS(),
765 (ConcurrentMarkSweepPolicy*) collector_policy());
766
767 if (collector == NULL || !collector->completed_initialization()) {
768 if (collector) {
769 delete collector; // Be nice in embedded situation
770 }
771 vm_shutdown_during_initialization("Could not create CMS collector");
772 return false;
773 }
774 return true; // success
775 }
776
777 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
778 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
779
780 MutexLocker ml(Heap_lock);
781 // Read the GC counts while holding the Heap_lock
782 unsigned int full_gc_count_before = total_full_collections();
783 unsigned int gc_count_before = total_collections();
810 local_max_level /* max_level */);
811 // Hack XXX FIX ME !!!
812 // A scavenge may not have been attempted, or may have
813 // been attempted and failed, because the old gen was too full
814 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
815 incremental_collection_will_fail(false /* don't consult_young */)) {
816 if (PrintGCDetails) {
817 gclog_or_tty->print_cr("GC locker: Trying a full collection "
818 "because scavenge failed");
819 }
820 // This time allow the old gen to be collected as well
821 do_collection(true /* full */,
822 clear_all_soft_refs /* clear_all_soft_refs */,
823 0 /* size */,
824 false /* is_tlab */,
825 n_gens() - 1 /* max_level */);
826 }
827 }
828
829 bool GenCollectedHeap::is_in_young(oop p) {
830 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
831 assert(result == _gens[0]->is_in_reserved(p),
832 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
833 return result;
834 }
835
836 // Returns "TRUE" iff "p" points into the committed areas of the heap.
837 bool GenCollectedHeap::is_in(const void* p) const {
838 #ifndef ASSERT
839 guarantee(VerifyBeforeGC ||
840 VerifyDuringGC ||
841 VerifyBeforeExit ||
842 VerifyDuringStartup ||
843 PrintAssembly ||
844 tty->count() != 0 || // already printing
845 VerifyAfterGC ||
846 VMError::fatal_error_in_progress(), "too expensive");
847
848 #endif
849 // This might be sped up with a cache of the last generation that
850 // answered yes.
851 for (int i = 0; i < _n_gens; i++) {
852 if (_gens[i]->is_in(p)) return true;
853 }
854 // Otherwise...
855 return false;
856 }
857
858 #ifdef ASSERT
859 // Don't implement this by using is_in_young(). This method is used
860 // in some cases to check that is_in_young() is correct.
861 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
862 assert(is_in_reserved(p) || p == NULL,
863 "Does not work if address is non-null and outside of the heap");
864 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
865 }
866 #endif
867
868 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
869 for (int i = 0; i < _n_gens; i++) {
870 _gens[i]->oop_iterate(cl);
871 }
872 }
873
874 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
875 for (int i = 0; i < _n_gens; i++) {
876 _gens[i]->object_iterate(cl);
877 }
878 }
879
880 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
881 for (int i = 0; i < _n_gens; i++) {
882 _gens[i]->safe_object_iterate(cl);
883 }
884 }
885
886 Space* GenCollectedHeap::space_containing(const void* addr) const {
887 for (int i = 0; i < _n_gens; i++) {
888 Space* res = _gens[i]->space_containing(addr);
889 if (res != NULL) return res;
890 }
891 // Otherwise...
892 assert(false, "Could not find containing space");
893 return NULL;
894 }
895
896
897 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
898 assert(is_in_reserved(addr), "block_start of address outside of heap");
899 for (int i = 0; i < _n_gens; i++) {
900 if (_gens[i]->is_in_reserved(addr)) {
901 assert(_gens[i]->is_in(addr),
902 "addr should be in allocated part of generation");
903 return _gens[i]->block_start(addr);
904 }
905 }
906 assert(false, "Some generation should contain the address");
907 return NULL;
908 }
909
910 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
911 assert(is_in_reserved(addr), "block_size of address outside of heap");
912 for (int i = 0; i < _n_gens; i++) {
913 if (_gens[i]->is_in_reserved(addr)) {
914 assert(_gens[i]->is_in(addr),
915 "addr should be in allocated part of generation");
916 return _gens[i]->block_size(addr);
917 }
918 }
919 assert(false, "Some generation should contain the address");
920 return 0;
921 }
922
923 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
924 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
925 assert(block_start(addr) == addr, "addr must be a block start");
926 for (int i = 0; i < _n_gens; i++) {
927 if (_gens[i]->is_in_reserved(addr)) {
928 return _gens[i]->block_is_obj(addr);
929 }
930 }
931 assert(false, "Some generation should contain the address");
932 return false;
933 }
934
935 bool GenCollectedHeap::supports_tlab_allocation() const {
936 for (int i = 0; i < _n_gens; i += 1) {
937 if (_gens[i]->supports_tlab_allocation()) {
938 return true;
939 }
940 }
941 return false;
942 }
943
944 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
945 size_t result = 0;
946 for (int i = 0; i < _n_gens; i += 1) {
947 if (_gens[i]->supports_tlab_allocation()) {
948 result += _gens[i]->tlab_capacity();
949 }
950 }
951 return result;
952 }
953
954 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
955 size_t result = 0;
956 for (int i = 0; i < _n_gens; i += 1) {
957 if (_gens[i]->supports_tlab_allocation()) {
958 result += _gens[i]->tlab_used();
959 }
960 }
961 return result;
962 }
963
964 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
965 size_t result = 0;
966 for (int i = 0; i < _n_gens; i += 1) {
967 if (_gens[i]->supports_tlab_allocation()) {
968 result += _gens[i]->unsafe_max_tlab_alloc();
969 }
970 }
971 return result;
972 }
973
974 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
975 bool gc_overhead_limit_was_exceeded;
976 return collector_policy()->mem_allocate_work(size /* size */,
977 true /* is_tlab */,
978 &gc_overhead_limit_was_exceeded);
979 }
980
981 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
982 // from the list headed by "*prev_ptr".
983 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
984 bool first = true;
985 size_t min_size = 0; // "first" makes this conceptually infinite.
986 ScratchBlock **smallest_ptr, *smallest;
987 ScratchBlock *cur = *prev_ptr;
988 while (cur) {
989 assert(*prev_ptr == cur, "just checking");
990 if (first || cur->num_words < min_size) {
991 smallest_ptr = prev_ptr;
1000 *smallest_ptr = smallest->next;
1001 return smallest;
1002 }
1003
1004 // Sort the scratch block list headed by res into decreasing size order,
1005 // and set "res" to the result.
1006 static void sort_scratch_list(ScratchBlock*& list) {
1007 ScratchBlock* sorted = NULL;
1008 ScratchBlock* unsorted = list;
1009 while (unsorted) {
1010 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1011 smallest->next = sorted;
1012 sorted = smallest;
1013 }
1014 list = sorted;
1015 }
1016
1017 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1018 size_t max_alloc_words) {
1019 ScratchBlock* res = NULL;
1020 for (int i = 0; i < _n_gens; i++) {
1021 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1022 }
1023 sort_scratch_list(res);
1024 return res;
1025 }
1026
1027 void GenCollectedHeap::release_scratch() {
1028 for (int i = 0; i < _n_gens; i++) {
1029 _gens[i]->reset_scratch();
1030 }
1031 }
1032
1033 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1034 void do_generation(Generation* gen) {
1035 gen->prepare_for_verify();
1036 }
1037 };
1038
1039 void GenCollectedHeap::prepare_for_verify() {
1040 ensure_parsability(false); // no need to retire TLABs
1041 GenPrepareForVerifyClosure blk;
1042 generation_iterate(&blk, false);
1043 }
1044
1045
1046 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1047 bool old_to_young) {
1048 if (old_to_young) {
1049 for (int i = _n_gens-1; i >= 0; i--) {
1050 cl->do_generation(_gens[i]);
1051 }
1052 } else {
1053 for (int i = 0; i < _n_gens; i++) {
1054 cl->do_generation(_gens[i]);
1055 }
1056 }
1057 }
1058
1059 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1060 for (int i = 0; i < _n_gens; i++) {
1061 _gens[i]->space_iterate(cl, true);
1062 }
1063 }
1064
1065 bool GenCollectedHeap::is_maximal_no_gc() const {
1066 for (int i = 0; i < _n_gens; i++) {
1067 if (!_gens[i]->is_maximal_no_gc()) {
1068 return false;
1069 }
1070 }
1071 return true;
1072 }
1073
1074 void GenCollectedHeap::save_marks() {
1075 for (int i = 0; i < _n_gens; i++) {
1076 _gens[i]->save_marks();
1077 }
1078 }
1079
1080 GenCollectedHeap* GenCollectedHeap::heap() {
1081 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1082 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1083 return _gch;
1084 }
1085
1086
1087 void GenCollectedHeap::prepare_for_compaction() {
1088 guarantee(_n_gens = 2, "Wrong number of generations");
1089 Generation* old_gen = _gens[1];
1090 // Start by compacting into same gen.
1091 CompactPoint cp(old_gen);
1092 old_gen->prepare_for_compaction(&cp);
1093 Generation* young_gen = _gens[0];
1094 young_gen->prepare_for_compaction(&cp);
1095 }
1096
1097 GCStats* GenCollectedHeap::gc_stats(int level) const {
1098 return _gens[level]->gc_stats();
1099 }
1100
1101 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1102 for (int i = _n_gens-1; i >= 0; i--) {
1103 Generation* g = _gens[i];
1104 if (!silent) {
1105 gclog_or_tty->print("%s", g->name());
1106 gclog_or_tty->print(" ");
1107 }
1108 g->verify();
1109 }
1110 if (!silent) {
1111 gclog_or_tty->print("remset ");
1112 }
1113 rem_set()->verify();
1114 }
1115
1116 void GenCollectedHeap::print_on(outputStream* st) const {
1117 for (int i = 0; i < _n_gens; i++) {
1118 _gens[i]->print_on(st);
1119 }
1120 MetaspaceAux::print_on(st);
1121 }
1122
1123 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1124 if (workers() != NULL) {
1125 workers()->threads_do(tc);
1126 }
1127 #if INCLUDE_ALL_GCS
1128 if (UseConcMarkSweepGC) {
1129 ConcurrentMarkSweepThread::threads_do(tc);
1130 }
1131 #endif // INCLUDE_ALL_GCS
1132 }
1133
1134 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1135 #if INCLUDE_ALL_GCS
1136 if (UseParNewGC) {
1137 workers()->print_worker_threads_on(st);
1138 }
1139 if (UseConcMarkSweepGC) {
|
121 vm_shutdown_during_initialization(
122 "Could not reserve enough space for object heap");
123 return JNI_ENOMEM;
124 }
125
126 _reserved = MemRegion((HeapWord*)heap_rs.base(),
127 (HeapWord*)(heap_rs.base() + heap_rs.size()));
128
129 // It is important to do this in a way such that concurrent readers can't
130 // temporarily think something is in the heap. (Seen this happen in asserts.)
131 _reserved.set_word_size(0);
132 _reserved.set_start((HeapWord*)heap_rs.base());
133 size_t actual_heap_size = heap_rs.size();
134 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
135
136 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
137 set_barrier_set(rem_set()->bs());
138
139 _gch = this;
140
141 ReservedSpace young_rs = heap_rs.first_part(_gen_specs[0]->max_size(), false, false);
142 _young_gen = _gen_specs[0]->init(young_rs, 0, rem_set());
143 heap_rs = heap_rs.last_part(_gen_specs[0]->max_size());
144
145 ReservedSpace old_rs = heap_rs.first_part(_gen_specs[1]->max_size(), false, false);
146 _old_gen = _gen_specs[1]->init(old_rs, 1, rem_set());
147 heap_rs = heap_rs.last_part(_gen_specs[1]->max_size());
148 clear_incremental_collection_failed();
149
150 #if INCLUDE_ALL_GCS
151 // If we are running CMS, create the collector responsible
152 // for collecting the CMS generations.
153 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
154 bool success = create_cms_collector();
155 if (!success) return JNI_ENOMEM;
156 }
157 #endif // INCLUDE_ALL_GCS
158
159 return JNI_OK;
160 }
161
162 char* GenCollectedHeap::allocate(size_t alignment,
163 size_t* _total_reserved,
164 int* _n_covered_regions,
165 ReservedSpace* heap_rs){
166 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
167 "the maximum representable size";
168
169 // Now figure out the total size.
170 size_t total_reserved = 0;
171 int n_covered_regions = 0;
172 const size_t pageSize = UseLargePages ?
173 os::large_page_size() : os::vm_page_size();
174
175 assert(alignment % pageSize == 0, "Must be");
176
177 for (int i = 0; i < _n_gens; i++) {
178 total_reserved += _gen_specs[i]->max_size();
179 if (total_reserved < _gen_specs[i]->max_size()) {
180 vm_exit_during_initialization(overflow_msg);
181 }
182 n_covered_regions += _gen_specs[i]->n_covered_regions();
183 }
184 assert(total_reserved % alignment == 0,
185 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
186 SIZE_FORMAT, total_reserved, alignment));
187
188 // Needed until the cardtable is fixed to have the right number
189 // of covered regions.
190 n_covered_regions += 2;
191
192 *_total_reserved = total_reserved;
193 *_n_covered_regions = n_covered_regions;
194
195 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
196 return heap_rs->base();
197 }
198
199 void GenCollectedHeap::post_initialize() {
200 SharedHeap::post_initialize();
201 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
202 guarantee(policy->is_generation_policy(), "Illegal policy type");
203 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
204 assert(def_new_gen->kind() == Generation::DefNew ||
205 def_new_gen->kind() == Generation::ParNew,
206 "Wrong generation kind");
207
208 Generation* old_gen = get_gen(1);
209 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
210 old_gen->kind() == Generation::MarkSweepCompact,
211 "Wrong generation kind");
212
213 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
214 old_gen->capacity(),
215 def_new_gen->from()->capacity());
216 policy->initialize_gc_policy_counters();
217 }
218
219 void GenCollectedHeap::ref_processing_init() {
220 SharedHeap::ref_processing_init();
221 _young_gen->ref_processor_init();
222 _old_gen->ref_processor_init();
223 }
224
225 size_t GenCollectedHeap::capacity() const {
226 return _young_gen->capacity() + _old_gen->capacity();
227 }
228
229 size_t GenCollectedHeap::used() const {
230 return _young_gen->used() + _old_gen->used();
231 }
232
233 // Save the "used_region" for generations level and lower.
234 void GenCollectedHeap::save_used_regions(int level) {
235 assert(level < _n_gens, "Illegal level parameter");
236 if (level == 1) {
237 _old_gen->save_used_region();
238 }
239 _young_gen->save_used_region();
240 }
241
242 size_t GenCollectedHeap::max_capacity() const {
243 return _young_gen->max_capacity() + _old_gen->max_capacity();
244 }
245
246 // Update the _full_collections_completed counter
247 // at the end of a stop-world full GC.
248 unsigned int GenCollectedHeap::update_full_collections_completed() {
249 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
250 assert(_full_collections_completed <= _total_full_collections,
251 "Can't complete more collections than were started");
252 _full_collections_completed = _total_full_collections;
253 ml.notify_all();
254 return _full_collections_completed;
255 }
256
257 // Update the _full_collections_completed counter, as appropriate,
258 // at the end of a concurrent GC cycle. Note the conditional update
259 // below to allow this method to be called by a concurrent collector
260 // without synchronizing in any manner with the VM thread (which
261 // may already have initiated a STW full collection "concurrently").
262 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
263 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
287 // higher than we are prepared to pay for such rudimentary debugging
288 // support.
289 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
290 size_t size) {
291 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
292 // We are asked to check a size in HeapWords,
293 // but the memory is mangled in juint words.
294 juint* start = (juint*) (addr + skip_header_HeapWords());
295 juint* end = (juint*) (addr + size);
296 for (juint* slot = start; slot < end; slot += 1) {
297 assert(*slot == badHeapWordVal,
298 "Found non badHeapWordValue in pre-allocation check");
299 }
300 }
301 }
302 #endif
303
304 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
305 bool is_tlab,
306 bool first_only) {
307 HeapWord* res = NULL;
308
309 if (_young_gen->should_allocate(size, is_tlab)) {
310 res = _young_gen->allocate(size, is_tlab);
311 if (res != NULL || first_only) {
312 return res;
313 }
314 }
315
316 if (_old_gen->should_allocate(size, is_tlab)) {
317 res = _old_gen->allocate(size, is_tlab);
318 }
319
320 return res;
321 }
322
323 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
324 bool* gc_overhead_limit_was_exceeded) {
325 return collector_policy()->mem_allocate_work(size,
326 false /* is_tlab */,
327 gc_overhead_limit_was_exceeded);
328 }
329
330 bool GenCollectedHeap::must_clear_all_soft_refs() {
331 return _gc_cause == GCCause::_last_ditch_collection;
332 }
333
334 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
335 return UseConcMarkSweepGC &&
336 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
337 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
338 }
339
340 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
341 bool is_tlab, bool run_verification, bool clear_soft_refs) {
342 // Timer for individual generations. Last argument is false: no CR
343 // FIXME: We should try to start the timing earlier to cover more of the GC pause
344 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
345 // so we can assume here that the next GC id is what we want.
346 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek());
347 TraceCollectorStats tcs(gen->counters());
348 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
349
350 size_t prev_used = gen->used();
351 gen->stat_record()->invocations++;
352 gen->stat_record()->accumulated_time.start();
353
354 // Must be done anew before each collection because
355 // a previous collection will do mangling and will
356 // change top of some spaces.
357 record_gen_tops_before_GC();
358
359 if (PrintGC && Verbose) {
360 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
361 gen->level(),
362 gen->stat_record()->invocations,
363 size * HeapWordSize);
364 }
365
366 if (run_verification && VerifyBeforeGC) {
367 HandleMark hm; // Discard invalid handles created during verification
368 Universe::verify(" VerifyBeforeGC:");
369 }
370 COMPILER2_PRESENT(DerivedPointerTable::clear());
371
372 // Do collection work
373 {
374 // Note on ref discovery: For what appear to be historical reasons,
375 // GCH enables and disabled (by enqueing) refs discovery.
376 // In the future this should be moved into the generation's
377 // collect method so that ref discovery and enqueueing concerns
378 // are local to a generation. The collect method could return
379 // an appropriate indication in the case that notification on
380 // the ref lock was needed. This will make the treatment of
381 // weak refs more uniform (and indeed remove such concerns
382 // from GCH). XXX
383
384 HandleMark hm; // Discard invalid handles created during gc
385 save_marks(); // save marks for all gens
386 // We want to discover references, but not process them yet.
387 // This mode is disabled in process_discovered_references if the
388 // generation does some collection work, or in
389 // enqueue_discovered_references if the generation returns
390 // without doing any work.
391 ReferenceProcessor* rp = gen->ref_processor();
392 // If the discovery of ("weak") refs in this generation is
393 // atomic wrt other collectors in this configuration, we
394 // are guaranteed to have empty discovered ref lists.
395 if (rp->discovery_is_atomic()) {
396 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
397 rp->setup_policy(clear_soft_refs);
398 } else {
399 // collect() below will enable discovery as appropriate
400 }
401 gen->collect(full, clear_soft_refs, size, is_tlab);
402 if (!rp->enqueuing_is_done()) {
403 rp->enqueue_discovered_references();
404 } else {
405 rp->set_enqueuing_is_done(false);
406 }
407 rp->verify_no_references_recorded();
408 }
409
410 // Determine if allocation request was met.
411 if (size > 0) {
412 if (!is_tlab || gen->supports_tlab_allocation()) {
413 if (size * HeapWordSize <= gen->unsafe_max_alloc_nogc()) {
414 size = 0;
415 }
416 }
417 }
418
419 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
420
421 gen->stat_record()->accumulated_time.stop();
422
423 update_gc_stats(gen->level(), full);
424
425 if (run_verification && VerifyAfterGC) {
426 HandleMark hm; // Discard invalid handles created during verification
427 Universe::verify(" VerifyAfterGC:");
428 }
429
430 if (PrintGCDetails) {
431 gclog_or_tty->print(":");
432 gen->print_heap_change(prev_used);
433 }
434 }
435
436 void GenCollectedHeap::do_collection(bool full,
437 bool clear_all_soft_refs,
438 size_t size,
439 bool is_tlab,
440 int max_level) {
441 ResourceMark rm;
442 DEBUG_ONLY(Thread* my_thread = Thread::current();)
443
444 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
445 assert(my_thread->is_VM_thread() ||
446 my_thread->is_ConcurrentGC_thread(),
447 "incorrect thread type capability");
448 assert(Heap_lock->is_locked(),
449 "the requesting thread should have the Heap_lock");
450 guarantee(!is_gc_active(), "collection is not reentrant");
451 assert(max_level < n_gens(), "sanity check");
452
453 if (GC_locker::check_active_before_gc()) {
454 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
455 }
456
457 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
458 collector_policy()->should_clear_all_soft_refs();
459
460 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
461
462 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
463
464 print_heap_before_gc();
465
466 {
467 FlagSetting fl(_is_gc_active, true);
468
469 bool complete = full && (max_level == (n_gens()-1));
470 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
471 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
472 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
473 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
474 // so we can assume here that the next GC id is what we want.
475 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
476
477 gc_prologue(complete);
478 increment_total_collections(complete);
479
480 size_t gch_prev_used = used();
481 bool must_restore_marks_for_biased_locking = false;
482 bool run_verification = total_collections() >= VerifyGCStartAt;
483
484 if (_young_gen->performs_in_place_marking() ||
485 _old_gen->performs_in_place_marking()) {
486 // We want to avoid doing this for
487 // scavenge-only collections where it's unnecessary.
488 must_restore_marks_for_biased_locking = true;
489 BiasedLocking::preserve_marks();
490 }
491
492 bool prepared_for_verification = false;
493 int max_level_collected = 0;
494 if (!(full && _old_gen->full_collects_younger_generations()) &&
495 _young_gen->should_collect(full, size, is_tlab)) {
496 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
497 prepare_for_verify();
498 prepared_for_verification = true;
499 }
500 collect_generation(_young_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 0, do_clear_all_soft_refs);
501 }
502 if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) {
503 if (!complete) {
504 // The full_collections increment was missed above.
505 increment_total_full_collections();
506 }
507 pre_full_gc_dump(NULL); // do any pre full gc dumps
508 if (run_verification && VerifyGCLevel <= 1 && VerifyBeforeGC) {
509 if (!prepared_for_verification) {
510 prepare_for_verify();
511 }
512 }
513 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs);
514 max_level_collected = 1;
515 }
516
517 // Update "complete" boolean wrt what actually transpired --
518 // for instance, a promotion failure could have led to
519 // a whole heap collection.
520 complete = complete || (max_level_collected == n_gens() - 1);
521
522 if (complete) { // We did a "major" collection
523 // FIXME: See comment at pre_full_gc_dump call
524 post_full_gc_dump(NULL); // do any post full gc dumps
525 }
526
527 if (PrintGCDetails) {
528 print_heap_change(gch_prev_used);
529
530 // Print metaspace info for full GC with PrintGCDetails flag.
531 if (complete) {
532 MetaspaceAux::print_metaspace_change(metadata_prev_used);
533 }
534 }
535
536 // Adjust generation sizes.
537 if (max_level_collected == 1) {
538 _old_gen->compute_new_size();
539 }
540 _young_gen->compute_new_size();
541
542 if (complete) {
543 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
544 ClassLoaderDataGraph::purge();
545 MetaspaceAux::verify_metrics();
546 // Resize the metaspace capacity after full collections
547 MetaspaceGC::compute_new_size();
548 update_full_collections_completed();
549 }
550
551 // Track memory usage and detect low memory after GC finishes
552 MemoryService::track_memory_usage();
553
554 gc_epilogue(complete);
555
556 if (must_restore_marks_for_biased_locking) {
557 BiasedLocking::restore_marks();
558 }
559 }
560
577 void GenCollectedHeap::
578 gen_process_roots(int level,
579 bool younger_gens_as_roots,
580 bool activate_scope,
581 SharedHeap::ScanningOption so,
582 OopsInGenClosure* not_older_gens,
583 OopsInGenClosure* weak_roots,
584 OopsInGenClosure* older_gens,
585 CLDClosure* cld_closure,
586 CLDClosure* weak_cld_closure,
587 CodeBlobClosure* code_closure) {
588
589 // General roots.
590 SharedHeap::process_roots(activate_scope, so,
591 not_older_gens, weak_roots,
592 cld_closure, weak_cld_closure,
593 code_closure);
594
595 if (younger_gens_as_roots) {
596 if (!_gen_process_roots_tasks->is_task_claimed(GCH_PS_younger_gens)) {
597 if (level == 1) {
598 not_older_gens->set_generation(_young_gen);
599 _young_gen->oop_iterate(not_older_gens);
600 }
601 not_older_gens->reset_generation();
602 }
603 }
604 // When collection is parallel, all threads get to cooperate to do
605 // older-gen scanning.
606 if (level == 0) {
607 older_gens->set_generation(_old_gen);
608 rem_set()->younger_refs_iterate(_old_gen, older_gens);
609 older_gens->reset_generation();
610 }
611
612 _gen_process_roots_tasks->all_tasks_completed();
613 }
614
615 void GenCollectedHeap::
616 gen_process_roots(int level,
617 bool younger_gens_as_roots,
618 bool activate_scope,
619 SharedHeap::ScanningOption so,
620 bool only_strong_roots,
621 OopsInGenClosure* not_older_gens,
622 OopsInGenClosure* older_gens,
623 CLDClosure* cld_closure) {
624
625 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
626
627 bool is_moving_collection = false;
628 if (level == 0 || is_adjust_phase) {
629 // young collections are always moving
630 is_moving_collection = true;
631 }
632
633 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
634 CodeBlobClosure* code_closure = &mark_code_closure;
635
636 gen_process_roots(level,
637 younger_gens_as_roots,
638 activate_scope, so,
639 not_older_gens, only_strong_roots ? NULL : not_older_gens,
640 older_gens,
641 cld_closure, only_strong_roots ? NULL : cld_closure,
642 code_closure);
643
644 }
645
646 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
647 SharedHeap::process_weak_roots(root_closure);
648 // "Local" "weak" refs
649 _young_gen->ref_processor()->weak_oops_do(root_closure);
650 _old_gen->ref_processor()->weak_oops_do(root_closure);
651 }
652
653 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
654 void GenCollectedHeap:: \
655 oop_since_save_marks_iterate(int level, \
656 OopClosureType* cur, \
657 OopClosureType* older) { \
658 if (level == 0) { \
659 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
660 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
661 } else { \
662 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
663 } \
664 }
665
666 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
667
668 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
669
670 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
671 if (level == 0) {
672 if (!_young_gen->no_allocs_since_save_marks()) return false;
673 }
674 if (!_old_gen->no_allocs_since_save_marks()) return false;
675 return true;
676 }
677
678 bool GenCollectedHeap::supports_inline_contig_alloc() const {
679 return _young_gen->supports_inline_contig_alloc();
680 }
681
682 HeapWord** GenCollectedHeap::top_addr() const {
683 return _young_gen->top_addr();
684 }
685
686 HeapWord** GenCollectedHeap::end_addr() const {
687 return _young_gen->end_addr();
688 }
689
690 // public collection interfaces
691
692 void GenCollectedHeap::collect(GCCause::Cause cause) {
693 if (should_do_concurrent_full_gc(cause)) {
694 #if INCLUDE_ALL_GCS
695 // mostly concurrent full collection
696 collect_mostly_concurrent(cause);
697 #else // INCLUDE_ALL_GCS
698 ShouldNotReachHere();
699 #endif // INCLUDE_ALL_GCS
700 } else {
701 #ifdef ASSERT
702 if (cause == GCCause::_scavenge_alot) {
703 // minor collection only
704 collect(cause, 0);
705 } else {
706 // Stop-the-world full collection
707 collect(cause, n_gens() - 1);
727 }
728
729 // this is the private collection interface
730 // The Heap_lock is expected to be held on entry.
731
732 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
733 // Read the GC count while holding the Heap_lock
734 unsigned int gc_count_before = total_collections();
735 unsigned int full_gc_count_before = total_full_collections();
736 {
737 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
738 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
739 cause, max_level);
740 VMThread::execute(&op);
741 }
742 }
743
744 #if INCLUDE_ALL_GCS
745 bool GenCollectedHeap::create_cms_collector() {
746
747 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
748 "Unexpected generation kinds");
749 // Skip two header words in the block content verification
750 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
751 CMSCollector* collector = new CMSCollector(
752 (ConcurrentMarkSweepGeneration*)_old_gen,
753 _rem_set->as_CardTableRS(),
754 (ConcurrentMarkSweepPolicy*) collector_policy());
755
756 if (collector == NULL || !collector->completed_initialization()) {
757 if (collector) {
758 delete collector; // Be nice in embedded situation
759 }
760 vm_shutdown_during_initialization("Could not create CMS collector");
761 return false;
762 }
763 return true; // success
764 }
765
766 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
767 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
768
769 MutexLocker ml(Heap_lock);
770 // Read the GC counts while holding the Heap_lock
771 unsigned int full_gc_count_before = total_full_collections();
772 unsigned int gc_count_before = total_collections();
799 local_max_level /* max_level */);
800 // Hack XXX FIX ME !!!
801 // A scavenge may not have been attempted, or may have
802 // been attempted and failed, because the old gen was too full
803 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
804 incremental_collection_will_fail(false /* don't consult_young */)) {
805 if (PrintGCDetails) {
806 gclog_or_tty->print_cr("GC locker: Trying a full collection "
807 "because scavenge failed");
808 }
809 // This time allow the old gen to be collected as well
810 do_collection(true /* full */,
811 clear_all_soft_refs /* clear_all_soft_refs */,
812 0 /* size */,
813 false /* is_tlab */,
814 n_gens() - 1 /* max_level */);
815 }
816 }
817
818 bool GenCollectedHeap::is_in_young(oop p) {
819 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
820 assert(result == _young_gen->is_in_reserved(p),
821 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
822 return result;
823 }
824
825 // Returns "TRUE" iff "p" points into the committed areas of the heap.
826 bool GenCollectedHeap::is_in(const void* p) const {
827 #ifndef ASSERT
828 guarantee(VerifyBeforeGC ||
829 VerifyDuringGC ||
830 VerifyBeforeExit ||
831 VerifyDuringStartup ||
832 PrintAssembly ||
833 tty->count() != 0 || // already printing
834 VerifyAfterGC ||
835 VMError::fatal_error_in_progress(), "too expensive");
836
837 #endif
838 // This might be sped up with a cache of the last generation that
839 // answered yes.
840 if (_young_gen->is_in(p) || _old_gen->is_in(p)) {
841 return true;
842 }
843 // Otherwise...
844 return false;
845 }
846
847 #ifdef ASSERT
848 // Don't implement this by using is_in_young(). This method is used
849 // in some cases to check that is_in_young() is correct.
850 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
851 assert(is_in_reserved(p) || p == NULL,
852 "Does not work if address is non-null and outside of the heap");
853 return p < _young_gen->reserved().end() && p != NULL;
854 }
855 #endif
856
857 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
858 _young_gen->oop_iterate(cl);
859 _old_gen->oop_iterate(cl);
860 }
861
862 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
863 _young_gen->object_iterate(cl);
864 _old_gen->object_iterate(cl);
865 }
866
867 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
868 _young_gen->safe_object_iterate(cl);
869 _old_gen->safe_object_iterate(cl);
870 }
871
872 Space* GenCollectedHeap::space_containing(const void* addr) const {
873 Space* res = _young_gen->space_containing(addr);
874 if (res != NULL) {
875 return res;
876 }
877 res = _old_gen->space_containing(addr);
878 assert(res != NULL, "Could not find containing space");
879 return res;
880 }
881
882 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
883 assert(is_in_reserved(addr), "block_start of address outside of heap");
884 if (_young_gen->is_in_reserved(addr)) {
885 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
886 return _young_gen->block_start(addr);
887 }
888
889 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
890 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
891 return _old_gen->block_start(addr);
892 }
893
894 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
895 assert(is_in_reserved(addr), "block_size of address outside of heap");
896 if (_young_gen->is_in_reserved(addr)) {
897 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
898 return _young_gen->block_size(addr);
899 }
900
901 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
902 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
903 return _old_gen->block_size(addr);
904 }
905
906 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
907 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
908 assert(block_start(addr) == addr, "addr must be a block start");
909 if (_young_gen->is_in_reserved(addr)) {
910 return _young_gen->block_is_obj(addr);
911 }
912
913 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
914 return _old_gen->block_is_obj(addr);
915 }
916
917 bool GenCollectedHeap::supports_tlab_allocation() const {
918 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
919 return _young_gen->supports_tlab_allocation();
920 }
921
922 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
923 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
924 if (_young_gen->supports_tlab_allocation()) {
925 return _young_gen->tlab_capacity();
926 }
927 return 0;
928 }
929
930 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
931 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
932 if (_young_gen->supports_tlab_allocation()) {
933 return _young_gen->tlab_used();
934 }
935 return 0;
936 }
937
938 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
939 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
940 if (_young_gen->supports_tlab_allocation()) {
941 return _young_gen->unsafe_max_tlab_alloc();
942 }
943 return 0;
944 }
945
946 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
947 bool gc_overhead_limit_was_exceeded;
948 return collector_policy()->mem_allocate_work(size /* size */,
949 true /* is_tlab */,
950 &gc_overhead_limit_was_exceeded);
951 }
952
953 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
954 // from the list headed by "*prev_ptr".
955 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
956 bool first = true;
957 size_t min_size = 0; // "first" makes this conceptually infinite.
958 ScratchBlock **smallest_ptr, *smallest;
959 ScratchBlock *cur = *prev_ptr;
960 while (cur) {
961 assert(*prev_ptr == cur, "just checking");
962 if (first || cur->num_words < min_size) {
963 smallest_ptr = prev_ptr;
972 *smallest_ptr = smallest->next;
973 return smallest;
974 }
975
976 // Sort the scratch block list headed by res into decreasing size order,
977 // and set "res" to the result.
978 static void sort_scratch_list(ScratchBlock*& list) {
979 ScratchBlock* sorted = NULL;
980 ScratchBlock* unsorted = list;
981 while (unsorted) {
982 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
983 smallest->next = sorted;
984 sorted = smallest;
985 }
986 list = sorted;
987 }
988
989 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
990 size_t max_alloc_words) {
991 ScratchBlock* res = NULL;
992 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
993 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
994 sort_scratch_list(res);
995 return res;
996 }
997
998 void GenCollectedHeap::release_scratch() {
999 _young_gen->reset_scratch();
1000 _old_gen->reset_scratch();
1001 }
1002
1003 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1004 void do_generation(Generation* gen) {
1005 gen->prepare_for_verify();
1006 }
1007 };
1008
1009 void GenCollectedHeap::prepare_for_verify() {
1010 ensure_parsability(false); // no need to retire TLABs
1011 GenPrepareForVerifyClosure blk;
1012 generation_iterate(&blk, false);
1013 }
1014
1015 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1016 bool old_to_young) {
1017 if (old_to_young) {
1018 cl->do_generation(_old_gen);
1019 cl->do_generation(_young_gen);
1020 } else {
1021 cl->do_generation(_young_gen);
1022 cl->do_generation(_old_gen);
1023 }
1024 }
1025
1026 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1027 _young_gen->space_iterate(cl, true);
1028 _old_gen->space_iterate(cl, true);
1029 }
1030
1031 bool GenCollectedHeap::is_maximal_no_gc() const {
1032 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1033 }
1034
1035 void GenCollectedHeap::save_marks() {
1036 _young_gen->save_marks();
1037 _old_gen->save_marks();
1038 }
1039
1040 GenCollectedHeap* GenCollectedHeap::heap() {
1041 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1042 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1043 return _gch;
1044 }
1045
1046
1047 void GenCollectedHeap::prepare_for_compaction() {
1048 guarantee(_n_gens = 2, "Wrong number of generations");
1049 Generation* old_gen = _old_gen;
1050 // Start by compacting into same gen.
1051 CompactPoint cp(old_gen);
1052 old_gen->prepare_for_compaction(&cp);
1053 Generation* young_gen = _young_gen;
1054 young_gen->prepare_for_compaction(&cp);
1055 }
1056
1057 GCStats* GenCollectedHeap::gc_stats(int level) const {
1058 if (level == 0) {
1059 return _young_gen->gc_stats();
1060 } else {
1061 return _old_gen->gc_stats();
1062 }
1063 }
1064
1065 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1066 if (!silent) {
1067 gclog_or_tty->print("%s", _old_gen->name());
1068 gclog_or_tty->print(" ");
1069 }
1070 _old_gen->verify();
1071
1072 if (!silent) {
1073 gclog_or_tty->print("%s", _young_gen->name());
1074 gclog_or_tty->print(" ");
1075 }
1076 _young_gen->verify();
1077
1078 if (!silent) {
1079 gclog_or_tty->print("remset ");
1080 }
1081 rem_set()->verify();
1082 }
1083
1084 void GenCollectedHeap::print_on(outputStream* st) const {
1085 _young_gen->print_on(st);
1086 _old_gen->print_on(st);
1087 MetaspaceAux::print_on(st);
1088 }
1089
1090 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1091 if (workers() != NULL) {
1092 workers()->threads_do(tc);
1093 }
1094 #if INCLUDE_ALL_GCS
1095 if (UseConcMarkSweepGC) {
1096 ConcurrentMarkSweepThread::threads_do(tc);
1097 }
1098 #endif // INCLUDE_ALL_GCS
1099 }
1100
1101 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1102 #if INCLUDE_ALL_GCS
1103 if (UseParNewGC) {
1104 workers()->print_worker_threads_on(st);
1105 }
1106 if (UseConcMarkSweepGC) {
|