111 size_t total_reserved = 0;
112 ReservedSpace heap_rs;
113
114 size_t heap_alignment = collector_policy()->heap_alignment();
115
116 heap_address = allocate(heap_alignment, &total_reserved, &heap_rs);
117
118 if (!heap_rs.is_reserved()) {
119 vm_shutdown_during_initialization(
120 "Could not reserve enough space for object heap");
121 return JNI_ENOMEM;
122 }
123
124 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
125
126 _rem_set = collector_policy()->create_rem_set(reserved_region());
127 set_barrier_set(rem_set()->bs());
128
129 _gch = this;
130
131 for (i = 0; i < _n_gens; i++) {
132 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(), false, false);
133 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
134 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
135 }
136 clear_incremental_collection_failed();
137
138 #if INCLUDE_ALL_GCS
139 // If we are running CMS, create the collector responsible
140 // for collecting the CMS generations.
141 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
142 bool success = create_cms_collector();
143 if (!success) return JNI_ENOMEM;
144 }
145 #endif // INCLUDE_ALL_GCS
146
147 return JNI_OK;
148 }
149
150
151 char* GenCollectedHeap::allocate(size_t alignment,
152 size_t* _total_reserved,
153 ReservedSpace* heap_rs){
154 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
155 "the maximum representable size";
156
157 // Now figure out the total size.
158 size_t total_reserved = 0;
159 const size_t pageSize = UseLargePages ?
160 os::large_page_size() : os::vm_page_size();
161
162 assert(alignment % pageSize == 0, "Must be");
163
164 for (int i = 0; i < _n_gens; i++) {
165 total_reserved += _gen_specs[i]->max_size();
166 if (total_reserved < _gen_specs[i]->max_size()) {
167 vm_exit_during_initialization(overflow_msg);
168 }
169 }
170 assert(total_reserved % alignment == 0,
171 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
172 SIZE_FORMAT, total_reserved, alignment));
173
174 *_total_reserved = total_reserved;
175
176 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
177 return heap_rs->base();
178 }
179
180
181 void GenCollectedHeap::post_initialize() {
182 SharedHeap::post_initialize();
183 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
184 guarantee(policy->is_generation_policy(), "Illegal policy type");
185 assert((get_gen(0)->kind() == Generation::DefNew) ||
186 (get_gen(0)->kind() == Generation::ParNew),
187 "Wrong youngest generation type");
188 DefNewGeneration* def_new_gen = (DefNewGeneration*)get_gen(0);
189
190 Generation* old_gen = get_gen(1);
191 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
192 old_gen->kind() == Generation::MarkSweepCompact,
193 "Wrong generation kind");
194
195 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
196 old_gen->capacity(),
197 def_new_gen->from()->capacity());
198 policy->initialize_gc_policy_counters();
199 }
200
201 void GenCollectedHeap::ref_processing_init() {
202 SharedHeap::ref_processing_init();
203 for (int i = 0; i < _n_gens; i++) {
204 _gens[i]->ref_processor_init();
205 }
206 }
207
208 size_t GenCollectedHeap::capacity() const {
209 size_t res = 0;
210 for (int i = 0; i < _n_gens; i++) {
211 res += _gens[i]->capacity();
212 }
213 return res;
214 }
215
216 size_t GenCollectedHeap::used() const {
217 size_t res = 0;
218 for (int i = 0; i < _n_gens; i++) {
219 res += _gens[i]->used();
220 }
221 return res;
222 }
223
224 // Save the "used_region" for generations level and lower.
225 void GenCollectedHeap::save_used_regions(int level) {
226 assert(level < _n_gens, "Illegal level parameter");
227 for (int i = level; i >= 0; i--) {
228 _gens[i]->save_used_region();
229 }
230 }
231
232 size_t GenCollectedHeap::max_capacity() const {
233 size_t res = 0;
234 for (int i = 0; i < _n_gens; i++) {
235 res += _gens[i]->max_capacity();
236 }
237 return res;
238 }
239
240 // Update the _full_collections_completed counter
241 // at the end of a stop-world full GC.
242 unsigned int GenCollectedHeap::update_full_collections_completed() {
243 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
244 assert(_full_collections_completed <= _total_full_collections,
245 "Can't complete more collections than were started");
246 _full_collections_completed = _total_full_collections;
247 ml.notify_all();
248 return _full_collections_completed;
249 }
250
251 // Update the _full_collections_completed counter, as appropriate,
252 // at the end of a concurrent GC cycle. Note the conditional update
253 // below to allow this method to be called by a concurrent collector
254 // without synchronizing in any manner with the VM thread (which
255 // may already have initiated a STW full collection "concurrently").
256 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
257 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
281 // higher than we are prepared to pay for such rudimentary debugging
282 // support.
283 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
284 size_t size) {
285 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
286 // We are asked to check a size in HeapWords,
287 // but the memory is mangled in juint words.
288 juint* start = (juint*) (addr + skip_header_HeapWords());
289 juint* end = (juint*) (addr + size);
290 for (juint* slot = start; slot < end; slot += 1) {
291 assert(*slot == badHeapWordVal,
292 "Found non badHeapWordValue in pre-allocation check");
293 }
294 }
295 }
296 #endif
297
298 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
299 bool is_tlab,
300 bool first_only) {
301 HeapWord* res;
302 for (int i = 0; i < _n_gens; i++) {
303 if (_gens[i]->should_allocate(size, is_tlab)) {
304 res = _gens[i]->allocate(size, is_tlab);
305 if (res != NULL) return res;
306 else if (first_only) break;
307 }
308 }
309 // Otherwise...
310 return NULL;
311 }
312
313 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
314 bool* gc_overhead_limit_was_exceeded) {
315 return collector_policy()->mem_allocate_work(size,
316 false /* is_tlab */,
317 gc_overhead_limit_was_exceeded);
318 }
319
320 bool GenCollectedHeap::must_clear_all_soft_refs() {
321 return _gc_cause == GCCause::_last_ditch_collection;
322 }
323
324 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
325 return UseConcMarkSweepGC &&
326 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
327 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
328 }
329
330 void GenCollectedHeap::do_collection(bool full,
331 bool clear_all_soft_refs,
332 size_t size,
333 bool is_tlab,
334 int max_level) {
335 bool prepared_for_verification = false;
336 ResourceMark rm;
337 DEBUG_ONLY(Thread* my_thread = Thread::current();)
338
339 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
340 assert(my_thread->is_VM_thread() ||
341 my_thread->is_ConcurrentGC_thread(),
342 "incorrect thread type capability");
343 assert(Heap_lock->is_locked(),
344 "the requesting thread should have the Heap_lock");
345 guarantee(!is_gc_active(), "collection is not reentrant");
346 assert(max_level < n_gens(), "sanity check");
347
348 if (GC_locker::check_active_before_gc()) {
349 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
350 }
351
352 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
353 collector_policy()->should_clear_all_soft_refs();
354
355 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
356
357 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
358
359 print_heap_before_gc();
360
361 {
362 FlagSetting fl(_is_gc_active, true);
363
364 bool complete = full && (max_level == (n_gens()-1));
365 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
366 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
367 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
368 // so we can assume here that the next GC id is what we want.
369 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
370
371 gc_prologue(complete);
372 increment_total_collections(complete);
373
374 size_t gch_prev_used = used();
375
376 int starting_level = 0;
377 if (full) {
378 // Search for the oldest generation which will collect all younger
379 // generations, and start collection loop there.
380 for (int i = max_level; i >= 0; i--) {
381 if (_gens[i]->full_collects_younger_generations()) {
382 starting_level = i;
383 break;
384 }
385 }
386 }
387
388 bool must_restore_marks_for_biased_locking = false;
389
390 int max_level_collected = starting_level;
391 for (int i = starting_level; i <= max_level; i++) {
392 if (_gens[i]->should_collect(full, size, is_tlab)) {
393 if (i == n_gens() - 1) { // a major collection is to happen
394 if (!complete) {
395 // The full_collections increment was missed above.
396 increment_total_full_collections();
397 }
398 pre_full_gc_dump(NULL); // do any pre full gc dumps
399 }
400 // Timer for individual generations. Last argument is false: no CR
401 // FIXME: We should try to start the timing earlier to cover more of the GC pause
402 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
403 // so we can assume here that the next GC id is what we want.
404 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL, GCId::peek());
405 TraceCollectorStats tcs(_gens[i]->counters());
406 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
407
408 size_t prev_used = _gens[i]->used();
409 _gens[i]->stat_record()->invocations++;
410 _gens[i]->stat_record()->accumulated_time.start();
411
412 // Must be done anew before each collection because
413 // a previous collection will do mangling and will
414 // change top of some spaces.
415 record_gen_tops_before_GC();
416
417 if (PrintGC && Verbose) {
418 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
419 i,
420 _gens[i]->stat_record()->invocations,
421 size*HeapWordSize);
422 }
423
424 if (VerifyBeforeGC && i >= VerifyGCLevel &&
425 total_collections() >= VerifyGCStartAt) {
426 HandleMark hm; // Discard invalid handles created during verification
427 if (!prepared_for_verification) {
428 prepare_for_verify();
429 prepared_for_verification = true;
430 }
431 Universe::verify(" VerifyBeforeGC:");
432 }
433 COMPILER2_PRESENT(DerivedPointerTable::clear());
434
435 if (!must_restore_marks_for_biased_locking &&
436 _gens[i]->performs_in_place_marking()) {
437 // We perform this mark word preservation work lazily
438 // because it's only at this point that we know whether we
439 // absolutely have to do it; we want to avoid doing it for
440 // scavenge-only collections where it's unnecessary
441 must_restore_marks_for_biased_locking = true;
442 BiasedLocking::preserve_marks();
443 }
444
445 // Do collection work
446 {
447 // Note on ref discovery: For what appear to be historical reasons,
448 // GCH enables and disabled (by enqueing) refs discovery.
449 // In the future this should be moved into the generation's
450 // collect method so that ref discovery and enqueueing concerns
451 // are local to a generation. The collect method could return
452 // an appropriate indication in the case that notification on
453 // the ref lock was needed. This will make the treatment of
454 // weak refs more uniform (and indeed remove such concerns
455 // from GCH). XXX
456
457 HandleMark hm; // Discard invalid handles created during gc
458 save_marks(); // save marks for all gens
459 // We want to discover references, but not process them yet.
460 // This mode is disabled in process_discovered_references if the
461 // generation does some collection work, or in
462 // enqueue_discovered_references if the generation returns
463 // without doing any work.
464 ReferenceProcessor* rp = _gens[i]->ref_processor();
465 // If the discovery of ("weak") refs in this generation is
466 // atomic wrt other collectors in this configuration, we
467 // are guaranteed to have empty discovered ref lists.
468 if (rp->discovery_is_atomic()) {
469 rp->enable_discovery();
470 rp->setup_policy(do_clear_all_soft_refs);
471 } else {
472 // collect() below will enable discovery as appropriate
473 }
474 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
475 if (!rp->enqueuing_is_done()) {
476 rp->enqueue_discovered_references();
477 } else {
478 rp->set_enqueuing_is_done(false);
479 }
480 rp->verify_no_references_recorded();
481 }
482 max_level_collected = i;
483
484 // Determine if allocation request was met.
485 if (size > 0) {
486 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
487 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
488 size = 0;
489 }
490 }
491 }
492
493 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
494
495 _gens[i]->stat_record()->accumulated_time.stop();
496
497 update_gc_stats(i, full);
498
499 if (VerifyAfterGC && i >= VerifyGCLevel &&
500 total_collections() >= VerifyGCStartAt) {
501 HandleMark hm; // Discard invalid handles created during verification
502 Universe::verify(" VerifyAfterGC:");
503 }
504
505 if (PrintGCDetails) {
506 gclog_or_tty->print(":");
507 _gens[i]->print_heap_change(prev_used);
508 }
509 }
510 }
511
512 // Update "complete" boolean wrt what actually transpired --
513 // for instance, a promotion failure could have led to
514 // a whole heap collection.
515 complete = complete || (max_level_collected == n_gens() - 1);
516
517 if (complete) { // We did a "major" collection
518 // FIXME: See comment at pre_full_gc_dump call
519 post_full_gc_dump(NULL); // do any post full gc dumps
520 }
521
522 if (PrintGCDetails) {
523 print_heap_change(gch_prev_used);
524
525 // Print metaspace info for full GC with PrintGCDetails flag.
526 if (complete) {
527 MetaspaceAux::print_metaspace_change(metadata_prev_used);
528 }
529 }
530
531 for (int j = max_level_collected; j >= 0; j -= 1) {
532 // Adjust generation sizes.
533 _gens[j]->compute_new_size();
534 }
535
536 if (complete) {
537 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
538 ClassLoaderDataGraph::purge();
539 MetaspaceAux::verify_metrics();
540 // Resize the metaspace capacity after full collections
541 MetaspaceGC::compute_new_size();
542 update_full_collections_completed();
543 }
544
545 // Track memory usage and detect low memory after GC finishes
546 MemoryService::track_memory_usage();
547
548 gc_epilogue(complete);
549
550 if (must_restore_marks_for_biased_locking) {
551 BiasedLocking::restore_marks();
552 }
553 }
554
571 void GenCollectedHeap::
572 gen_process_roots(int level,
573 bool younger_gens_as_roots,
574 bool activate_scope,
575 SharedHeap::ScanningOption so,
576 OopsInGenClosure* not_older_gens,
577 OopsInGenClosure* weak_roots,
578 OopsInGenClosure* older_gens,
579 CLDClosure* cld_closure,
580 CLDClosure* weak_cld_closure,
581 CodeBlobClosure* code_closure) {
582
583 // General roots.
584 SharedHeap::process_roots(activate_scope, so,
585 not_older_gens, weak_roots,
586 cld_closure, weak_cld_closure,
587 code_closure);
588
589 if (younger_gens_as_roots) {
590 if (!_gen_process_roots_tasks->is_task_claimed(GCH_PS_younger_gens)) {
591 for (int i = 0; i < level; i++) {
592 not_older_gens->set_generation(_gens[i]);
593 _gens[i]->oop_iterate(not_older_gens);
594 }
595 not_older_gens->reset_generation();
596 }
597 }
598 // When collection is parallel, all threads get to cooperate to do
599 // older-gen scanning.
600 for (int i = level+1; i < _n_gens; i++) {
601 older_gens->set_generation(_gens[i]);
602 rem_set()->younger_refs_iterate(_gens[i], older_gens);
603 older_gens->reset_generation();
604 }
605
606 _gen_process_roots_tasks->all_tasks_completed();
607 }
608
609 void GenCollectedHeap::
610 gen_process_roots(int level,
611 bool younger_gens_as_roots,
612 bool activate_scope,
613 SharedHeap::ScanningOption so,
614 bool only_strong_roots,
615 OopsInGenClosure* not_older_gens,
616 OopsInGenClosure* older_gens,
617 CLDClosure* cld_closure) {
618
619 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
620
621 bool is_moving_collection = false;
622 if (level == 0 || is_adjust_phase) {
623 // young collections are always moving
624 is_moving_collection = true;
625 }
626
627 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
628 CodeBlobClosure* code_closure = &mark_code_closure;
629
630 gen_process_roots(level,
631 younger_gens_as_roots,
632 activate_scope, so,
633 not_older_gens, only_strong_roots ? NULL : not_older_gens,
634 older_gens,
635 cld_closure, only_strong_roots ? NULL : cld_closure,
636 code_closure);
637
638 }
639
640 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
641 SharedHeap::process_weak_roots(root_closure);
642 // "Local" "weak" refs
643 for (int i = 0; i < _n_gens; i++) {
644 _gens[i]->ref_processor()->weak_oops_do(root_closure);
645 }
646 }
647
648 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
649 void GenCollectedHeap:: \
650 oop_since_save_marks_iterate(int level, \
651 OopClosureType* cur, \
652 OopClosureType* older) { \
653 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
654 for (int i = level+1; i < n_gens(); i++) { \
655 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
656 } \
657 }
658
659 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
660
661 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
662
663 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
664 for (int i = level; i < _n_gens; i++) {
665 if (!_gens[i]->no_allocs_since_save_marks()) return false;
666 }
667 return true;
668 }
669
670 bool GenCollectedHeap::supports_inline_contig_alloc() const {
671 return _gens[0]->supports_inline_contig_alloc();
672 }
673
674 HeapWord** GenCollectedHeap::top_addr() const {
675 return _gens[0]->top_addr();
676 }
677
678 HeapWord** GenCollectedHeap::end_addr() const {
679 return _gens[0]->end_addr();
680 }
681
682 // public collection interfaces
683
684 void GenCollectedHeap::collect(GCCause::Cause cause) {
685 if (should_do_concurrent_full_gc(cause)) {
686 #if INCLUDE_ALL_GCS
687 // mostly concurrent full collection
688 collect_mostly_concurrent(cause);
689 #else // INCLUDE_ALL_GCS
690 ShouldNotReachHere();
691 #endif // INCLUDE_ALL_GCS
692 } else if (cause == GCCause::_wb_young_gc) {
693 // minor collection for WhiteBox API
694 collect(cause, 0);
695 } else {
696 #ifdef ASSERT
697 if (cause == GCCause::_scavenge_alot) {
698 // minor collection only
699 collect(cause, 0);
722 }
723
724 // this is the private collection interface
725 // The Heap_lock is expected to be held on entry.
726
727 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
728 // Read the GC count while holding the Heap_lock
729 unsigned int gc_count_before = total_collections();
730 unsigned int full_gc_count_before = total_full_collections();
731 {
732 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
733 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
734 cause, max_level);
735 VMThread::execute(&op);
736 }
737 }
738
739 #if INCLUDE_ALL_GCS
740 bool GenCollectedHeap::create_cms_collector() {
741
742 assert(_gens[1]->kind() == Generation::ConcurrentMarkSweep,
743 "Unexpected generation kinds");
744 // Skip two header words in the block content verification
745 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
746 CMSCollector* collector = new CMSCollector(
747 (ConcurrentMarkSweepGeneration*)_gens[1],
748 _rem_set->as_CardTableRS(),
749 (ConcurrentMarkSweepPolicy*) collector_policy());
750
751 if (collector == NULL || !collector->completed_initialization()) {
752 if (collector) {
753 delete collector; // Be nice in embedded situation
754 }
755 vm_shutdown_during_initialization("Could not create CMS collector");
756 return false;
757 }
758 return true; // success
759 }
760
761 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
762 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
763
764 MutexLocker ml(Heap_lock);
765 // Read the GC counts while holding the Heap_lock
766 unsigned int full_gc_count_before = total_full_collections();
767 unsigned int gc_count_before = total_collections();
794 local_max_level /* max_level */);
795 // Hack XXX FIX ME !!!
796 // A scavenge may not have been attempted, or may have
797 // been attempted and failed, because the old gen was too full
798 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
799 incremental_collection_will_fail(false /* don't consult_young */)) {
800 if (PrintGCDetails) {
801 gclog_or_tty->print_cr("GC locker: Trying a full collection "
802 "because scavenge failed");
803 }
804 // This time allow the old gen to be collected as well
805 do_collection(true /* full */,
806 clear_all_soft_refs /* clear_all_soft_refs */,
807 0 /* size */,
808 false /* is_tlab */,
809 n_gens() - 1 /* max_level */);
810 }
811 }
812
813 bool GenCollectedHeap::is_in_young(oop p) {
814 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
815 assert(result == _gens[0]->is_in_reserved(p),
816 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
817 return result;
818 }
819
820 // Returns "TRUE" iff "p" points into the committed areas of the heap.
821 bool GenCollectedHeap::is_in(const void* p) const {
822 #ifndef ASSERT
823 guarantee(VerifyBeforeGC ||
824 VerifyDuringGC ||
825 VerifyBeforeExit ||
826 VerifyDuringStartup ||
827 PrintAssembly ||
828 tty->count() != 0 || // already printing
829 VerifyAfterGC ||
830 VMError::fatal_error_in_progress(), "too expensive");
831
832 #endif
833 // This might be sped up with a cache of the last generation that
834 // answered yes.
835 for (int i = 0; i < _n_gens; i++) {
836 if (_gens[i]->is_in(p)) return true;
837 }
838 // Otherwise...
839 return false;
840 }
841
842 #ifdef ASSERT
843 // Don't implement this by using is_in_young(). This method is used
844 // in some cases to check that is_in_young() is correct.
845 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
846 assert(is_in_reserved(p) || p == NULL,
847 "Does not work if address is non-null and outside of the heap");
848 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
849 }
850 #endif
851
852 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
853 for (int i = 0; i < _n_gens; i++) {
854 _gens[i]->oop_iterate(cl);
855 }
856 }
857
858 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
859 for (int i = 0; i < _n_gens; i++) {
860 _gens[i]->object_iterate(cl);
861 }
862 }
863
864 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
865 for (int i = 0; i < _n_gens; i++) {
866 _gens[i]->safe_object_iterate(cl);
867 }
868 }
869
870 Space* GenCollectedHeap::space_containing(const void* addr) const {
871 for (int i = 0; i < _n_gens; i++) {
872 Space* res = _gens[i]->space_containing(addr);
873 if (res != NULL) return res;
874 }
875 // Otherwise...
876 assert(false, "Could not find containing space");
877 return NULL;
878 }
879
880
881 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
882 assert(is_in_reserved(addr), "block_start of address outside of heap");
883 for (int i = 0; i < _n_gens; i++) {
884 if (_gens[i]->is_in_reserved(addr)) {
885 assert(_gens[i]->is_in(addr),
886 "addr should be in allocated part of generation");
887 return _gens[i]->block_start(addr);
888 }
889 }
890 assert(false, "Some generation should contain the address");
891 return NULL;
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 for (int i = 0; i < _n_gens; i++) {
897 if (_gens[i]->is_in_reserved(addr)) {
898 assert(_gens[i]->is_in(addr),
899 "addr should be in allocated part of generation");
900 return _gens[i]->block_size(addr);
901 }
902 }
903 assert(false, "Some generation should contain the address");
904 return 0;
905 }
906
907 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
908 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
909 assert(block_start(addr) == addr, "addr must be a block start");
910 for (int i = 0; i < _n_gens; i++) {
911 if (_gens[i]->is_in_reserved(addr)) {
912 return _gens[i]->block_is_obj(addr);
913 }
914 }
915 assert(false, "Some generation should contain the address");
916 return false;
917 }
918
919 bool GenCollectedHeap::supports_tlab_allocation() const {
920 for (int i = 0; i < _n_gens; i += 1) {
921 if (_gens[i]->supports_tlab_allocation()) {
922 return true;
923 }
924 }
925 return false;
926 }
927
928 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
929 size_t result = 0;
930 for (int i = 0; i < _n_gens; i += 1) {
931 if (_gens[i]->supports_tlab_allocation()) {
932 result += _gens[i]->tlab_capacity();
933 }
934 }
935 return result;
936 }
937
938 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
939 size_t result = 0;
940 for (int i = 0; i < _n_gens; i += 1) {
941 if (_gens[i]->supports_tlab_allocation()) {
942 result += _gens[i]->tlab_used();
943 }
944 }
945 return result;
946 }
947
948 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
949 size_t result = 0;
950 for (int i = 0; i < _n_gens; i += 1) {
951 if (_gens[i]->supports_tlab_allocation()) {
952 result += _gens[i]->unsafe_max_tlab_alloc();
953 }
954 }
955 return result;
956 }
957
958 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
959 bool gc_overhead_limit_was_exceeded;
960 return collector_policy()->mem_allocate_work(size /* size */,
961 true /* is_tlab */,
962 &gc_overhead_limit_was_exceeded);
963 }
964
965 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
966 // from the list headed by "*prev_ptr".
967 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
968 bool first = true;
969 size_t min_size = 0; // "first" makes this conceptually infinite.
970 ScratchBlock **smallest_ptr, *smallest;
971 ScratchBlock *cur = *prev_ptr;
972 while (cur) {
973 assert(*prev_ptr == cur, "just checking");
974 if (first || cur->num_words < min_size) {
975 smallest_ptr = prev_ptr;
984 *smallest_ptr = smallest->next;
985 return smallest;
986 }
987
988 // Sort the scratch block list headed by res into decreasing size order,
989 // and set "res" to the result.
990 static void sort_scratch_list(ScratchBlock*& list) {
991 ScratchBlock* sorted = NULL;
992 ScratchBlock* unsorted = list;
993 while (unsorted) {
994 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
995 smallest->next = sorted;
996 sorted = smallest;
997 }
998 list = sorted;
999 }
1000
1001 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1002 size_t max_alloc_words) {
1003 ScratchBlock* res = NULL;
1004 for (int i = 0; i < _n_gens; i++) {
1005 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1006 }
1007 sort_scratch_list(res);
1008 return res;
1009 }
1010
1011 void GenCollectedHeap::release_scratch() {
1012 for (int i = 0; i < _n_gens; i++) {
1013 _gens[i]->reset_scratch();
1014 }
1015 }
1016
1017 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1018 void do_generation(Generation* gen) {
1019 gen->prepare_for_verify();
1020 }
1021 };
1022
1023 void GenCollectedHeap::prepare_for_verify() {
1024 ensure_parsability(false); // no need to retire TLABs
1025 GenPrepareForVerifyClosure blk;
1026 generation_iterate(&blk, false);
1027 }
1028
1029
1030 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1031 bool old_to_young) {
1032 if (old_to_young) {
1033 for (int i = _n_gens-1; i >= 0; i--) {
1034 cl->do_generation(_gens[i]);
1035 }
1036 } else {
1037 for (int i = 0; i < _n_gens; i++) {
1038 cl->do_generation(_gens[i]);
1039 }
1040 }
1041 }
1042
1043 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1044 for (int i = 0; i < _n_gens; i++) {
1045 _gens[i]->space_iterate(cl, true);
1046 }
1047 }
1048
1049 bool GenCollectedHeap::is_maximal_no_gc() const {
1050 for (int i = 0; i < _n_gens; i++) {
1051 if (!_gens[i]->is_maximal_no_gc()) {
1052 return false;
1053 }
1054 }
1055 return true;
1056 }
1057
1058 void GenCollectedHeap::save_marks() {
1059 for (int i = 0; i < _n_gens; i++) {
1060 _gens[i]->save_marks();
1061 }
1062 }
1063
1064 GenCollectedHeap* GenCollectedHeap::heap() {
1065 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1066 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1067 return _gch;
1068 }
1069
1070
1071 void GenCollectedHeap::prepare_for_compaction() {
1072 guarantee(_n_gens = 2, "Wrong number of generations");
1073 Generation* old_gen = _gens[1];
1074 // Start by compacting into same gen.
1075 CompactPoint cp(old_gen);
1076 old_gen->prepare_for_compaction(&cp);
1077 Generation* young_gen = _gens[0];
1078 young_gen->prepare_for_compaction(&cp);
1079 }
1080
1081 GCStats* GenCollectedHeap::gc_stats(int level) const {
1082 return _gens[level]->gc_stats();
1083 }
1084
1085 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1086 for (int i = _n_gens-1; i >= 0; i--) {
1087 Generation* g = _gens[i];
1088 if (!silent) {
1089 gclog_or_tty->print("%s", g->name());
1090 gclog_or_tty->print(" ");
1091 }
1092 g->verify();
1093 }
1094 if (!silent) {
1095 gclog_or_tty->print("remset ");
1096 }
1097 rem_set()->verify();
1098 }
1099
1100 void GenCollectedHeap::print_on(outputStream* st) const {
1101 for (int i = 0; i < _n_gens; i++) {
1102 _gens[i]->print_on(st);
1103 }
1104 MetaspaceAux::print_on(st);
1105 }
1106
1107 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1108 if (workers() != NULL) {
1109 workers()->threads_do(tc);
1110 }
1111 #if INCLUDE_ALL_GCS
1112 if (UseConcMarkSweepGC) {
1113 ConcurrentMarkSweepThread::threads_do(tc);
1114 }
1115 #endif // INCLUDE_ALL_GCS
1116 }
1117
1118 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1119 #if INCLUDE_ALL_GCS
1120 if (UseConcMarkSweepGC) {
1121 workers()->print_worker_threads_on(st);
1122 ConcurrentMarkSweepThread::print_all_on(st);
1123 }
|
111 size_t total_reserved = 0;
112 ReservedSpace heap_rs;
113
114 size_t heap_alignment = collector_policy()->heap_alignment();
115
116 heap_address = allocate(heap_alignment, &total_reserved, &heap_rs);
117
118 if (!heap_rs.is_reserved()) {
119 vm_shutdown_during_initialization(
120 "Could not reserve enough space for object heap");
121 return JNI_ENOMEM;
122 }
123
124 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
125
126 _rem_set = collector_policy()->create_rem_set(reserved_region());
127 set_barrier_set(rem_set()->bs());
128
129 _gch = this;
130
131 ReservedSpace young_rs = heap_rs.first_part(_gen_specs[0]->max_size(), false, false);
132 _young_gen = _gen_specs[0]->init(young_rs, 0, rem_set());
133 heap_rs = heap_rs.last_part(_gen_specs[0]->max_size());
134
135 ReservedSpace old_rs = heap_rs.first_part(_gen_specs[1]->max_size(), false, false);
136 _old_gen = _gen_specs[1]->init(old_rs, 1, rem_set());
137 heap_rs = heap_rs.last_part(_gen_specs[1]->max_size());
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 size_t* _total_reserved,
154 ReservedSpace* heap_rs){
155 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
156 "the maximum representable size";
157
158 // Now figure out the total size.
159 size_t total_reserved = 0;
160 const size_t pageSize = UseLargePages ?
161 os::large_page_size() : os::vm_page_size();
162
163 assert(alignment % pageSize == 0, "Must be");
164
165 for (int i = 0; i < _n_gens; i++) {
166 total_reserved += _gen_specs[i]->max_size();
167 if (total_reserved < _gen_specs[i]->max_size()) {
168 vm_exit_during_initialization(overflow_msg);
169 }
170 }
171 assert(total_reserved % alignment == 0,
172 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
173 SIZE_FORMAT, total_reserved, alignment));
174
175 *_total_reserved = total_reserved;
176
177 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
178 return heap_rs->base();
179 }
180
181 void GenCollectedHeap::post_initialize() {
182 SharedHeap::post_initialize();
183 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
184 guarantee(policy->is_generation_policy(), "Illegal policy type");
185 assert((get_gen(0)->kind() == Generation::DefNew) ||
186 (get_gen(0)->kind() == Generation::ParNew),
187 "Wrong youngest generation type");
188 DefNewGeneration* def_new_gen = (DefNewGeneration*)get_gen(0);
189
190 Generation* old_gen = get_gen(1);
191 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
192 old_gen->kind() == Generation::MarkSweepCompact,
193 "Wrong generation kind");
194
195 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
196 old_gen->capacity(),
197 def_new_gen->from()->capacity());
198 policy->initialize_gc_policy_counters();
199 }
200
201 void GenCollectedHeap::ref_processing_init() {
202 SharedHeap::ref_processing_init();
203 _young_gen->ref_processor_init();
204 _old_gen->ref_processor_init();
205 }
206
207 size_t GenCollectedHeap::capacity() const {
208 return _young_gen->capacity() + _old_gen->capacity();
209 }
210
211 size_t GenCollectedHeap::used() const {
212 return _young_gen->used() + _old_gen->used();
213 }
214
215 // Save the "used_region" for generations level and lower.
216 void GenCollectedHeap::save_used_regions(int level) {
217 assert(level < _n_gens, "Illegal level parameter");
218 if (level == 1) {
219 _old_gen->save_used_region();
220 }
221 _young_gen->save_used_region();
222 }
223
224 size_t GenCollectedHeap::max_capacity() const {
225 return _young_gen->max_capacity() + _old_gen->max_capacity();
226 }
227
228 // Update the _full_collections_completed counter
229 // at the end of a stop-world full GC.
230 unsigned int GenCollectedHeap::update_full_collections_completed() {
231 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
232 assert(_full_collections_completed <= _total_full_collections,
233 "Can't complete more collections than were started");
234 _full_collections_completed = _total_full_collections;
235 ml.notify_all();
236 return _full_collections_completed;
237 }
238
239 // Update the _full_collections_completed counter, as appropriate,
240 // at the end of a concurrent GC cycle. Note the conditional update
241 // below to allow this method to be called by a concurrent collector
242 // without synchronizing in any manner with the VM thread (which
243 // may already have initiated a STW full collection "concurrently").
244 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
245 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
269 // higher than we are prepared to pay for such rudimentary debugging
270 // support.
271 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
272 size_t size) {
273 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
274 // We are asked to check a size in HeapWords,
275 // but the memory is mangled in juint words.
276 juint* start = (juint*) (addr + skip_header_HeapWords());
277 juint* end = (juint*) (addr + size);
278 for (juint* slot = start; slot < end; slot += 1) {
279 assert(*slot == badHeapWordVal,
280 "Found non badHeapWordValue in pre-allocation check");
281 }
282 }
283 }
284 #endif
285
286 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
287 bool is_tlab,
288 bool first_only) {
289 HeapWord* res = NULL;
290
291 if (_young_gen->should_allocate(size, is_tlab)) {
292 res = _young_gen->allocate(size, is_tlab);
293 if (res != NULL || first_only) {
294 return res;
295 }
296 }
297
298 if (_old_gen->should_allocate(size, is_tlab)) {
299 res = _old_gen->allocate(size, is_tlab);
300 }
301
302 return res;
303 }
304
305 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
306 bool* gc_overhead_limit_was_exceeded) {
307 return collector_policy()->mem_allocate_work(size,
308 false /* is_tlab */,
309 gc_overhead_limit_was_exceeded);
310 }
311
312 bool GenCollectedHeap::must_clear_all_soft_refs() {
313 return _gc_cause == GCCause::_last_ditch_collection;
314 }
315
316 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
317 return UseConcMarkSweepGC &&
318 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
319 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
320 }
321
322 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
323 bool is_tlab, bool run_verification, bool clear_soft_refs,
324 bool restore_marks_for_biased_locking) {
325 // Timer for individual generations. Last argument is false: no CR
326 // FIXME: We should try to start the timing earlier to cover more of the GC pause
327 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
328 // so we can assume here that the next GC id is what we want.
329 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek());
330 TraceCollectorStats tcs(gen->counters());
331 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
332
333 size_t prev_used = gen->used();
334 gen->stat_record()->invocations++;
335 gen->stat_record()->accumulated_time.start();
336
337 // Must be done anew before each collection because
338 // a previous collection will do mangling and will
339 // change top of some spaces.
340 record_gen_tops_before_GC();
341
342 if (PrintGC && Verbose) {
343 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
344 gen->level(),
345 gen->stat_record()->invocations,
346 size * HeapWordSize);
347 }
348
349 if (run_verification && VerifyBeforeGC) {
350 HandleMark hm; // Discard invalid handles created during verification
351 Universe::verify(" VerifyBeforeGC:");
352 }
353 COMPILER2_PRESENT(DerivedPointerTable::clear());
354
355 if (restore_marks_for_biased_locking) {
356 // We perform this mark word preservation work lazily
357 // because it's only at this point that we know whether we
358 // absolutely have to do it; we want to avoid doing it for
359 // scavenge-only collections where it's unnecessary
360 BiasedLocking::preserve_marks();
361 }
362
363 // Do collection work
364 {
365 // Note on ref discovery: For what appear to be historical reasons,
366 // GCH enables and disabled (by enqueing) refs discovery.
367 // In the future this should be moved into the generation's
368 // collect method so that ref discovery and enqueueing concerns
369 // are local to a generation. The collect method could return
370 // an appropriate indication in the case that notification on
371 // the ref lock was needed. This will make the treatment of
372 // weak refs more uniform (and indeed remove such concerns
373 // from GCH). XXX
374
375 HandleMark hm; // Discard invalid handles created during gc
376 save_marks(); // save marks for all gens
377 // We want to discover references, but not process them yet.
378 // This mode is disabled in process_discovered_references if the
379 // generation does some collection work, or in
380 // enqueue_discovered_references if the generation returns
381 // without doing any work.
382 ReferenceProcessor* rp = gen->ref_processor();
383 // If the discovery of ("weak") refs in this generation is
384 // atomic wrt other collectors in this configuration, we
385 // are guaranteed to have empty discovered ref lists.
386 if (rp->discovery_is_atomic()) {
387 rp->enable_discovery();
388 rp->setup_policy(clear_soft_refs);
389 } else {
390 // collect() below will enable discovery as appropriate
391 }
392 gen->collect(full, clear_soft_refs, size, is_tlab);
393 if (!rp->enqueuing_is_done()) {
394 rp->enqueue_discovered_references();
395 } else {
396 rp->set_enqueuing_is_done(false);
397 }
398 rp->verify_no_references_recorded();
399 }
400
401 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
402
403 gen->stat_record()->accumulated_time.stop();
404
405 update_gc_stats(gen->level(), full);
406
407 if (run_verification && VerifyAfterGC) {
408 HandleMark hm; // Discard invalid handles created during verification
409 Universe::verify(" VerifyAfterGC:");
410 }
411
412 if (PrintGCDetails) {
413 gclog_or_tty->print(":");
414 gen->print_heap_change(prev_used);
415 }
416 }
417
418 void GenCollectedHeap::do_collection(bool full,
419 bool clear_all_soft_refs,
420 size_t size,
421 bool is_tlab,
422 int max_level) {
423 ResourceMark rm;
424 DEBUG_ONLY(Thread* my_thread = Thread::current();)
425
426 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
427 assert(my_thread->is_VM_thread() ||
428 my_thread->is_ConcurrentGC_thread(),
429 "incorrect thread type capability");
430 assert(Heap_lock->is_locked(),
431 "the requesting thread should have the Heap_lock");
432 guarantee(!is_gc_active(), "collection is not reentrant");
433 assert(max_level < n_gens(), "sanity check");
434
435 if (GC_locker::check_active_before_gc()) {
436 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
437 }
438
439 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
440 collector_policy()->should_clear_all_soft_refs();
441
442 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
443
444 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
445
446 print_heap_before_gc();
447
448 {
449 FlagSetting fl(_is_gc_active, true);
450
451 bool complete = full && (max_level == (n_gens()-1));
452 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
453 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
454 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
455 // so we can assume here that the next GC id is what we want.
456 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
457
458 gc_prologue(complete);
459 increment_total_collections(complete);
460
461 size_t gch_prev_used = used();
462 bool must_restore_marks_for_biased_locking = false;
463 bool run_verification = total_collections() >= VerifyGCStartAt;
464
465 bool prepared_for_verification = false;
466 int max_level_collected = 0;
467 if (!(max_level == 1 && full && _old_gen->full_collects_younger_generations()) &&
468 _young_gen->should_collect(full, size, is_tlab)) {
469 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
470 prepare_for_verify();
471 prepared_for_verification = true;
472 }
473 if (_young_gen->performs_in_place_marking()) {
474 must_restore_marks_for_biased_locking = true;
475 }
476 collect_generation(_young_gen,
477 full,
478 size,
479 is_tlab,
480 run_verification && VerifyGCLevel <= 0,
481 do_clear_all_soft_refs,
482 must_restore_marks_for_biased_locking);
483
484 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
485 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
486 // Allocation request was met by young GC.
487 size = 0;
488 }
489 }
490
491 if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) {
492 if (!complete) {
493 // The full_collections increment was missed above.
494 increment_total_full_collections();
495 }
496 pre_full_gc_dump(NULL); // do any pre full gc dumps
497 if (!prepared_for_verification && run_verification &&
498 VerifyGCLevel <= 1 && VerifyBeforeGC) {
499 prepare_for_verify();
500 }
501 assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking");
502 collect_generation(_old_gen,
503 full,
504 size,
505 is_tlab,
506 run_verification && VerifyGCLevel <= 1,
507 do_clear_all_soft_refs,
508 !must_restore_marks_for_biased_locking);
509
510 must_restore_marks_for_biased_locking = true;
511 max_level_collected = 1;
512 }
513
514 // Update "complete" boolean wrt what actually transpired --
515 // for instance, a promotion failure could have led to
516 // a whole heap collection.
517 complete = complete || (max_level_collected == n_gens() - 1);
518
519 if (complete) { // We did a "major" collection
520 // FIXME: See comment at pre_full_gc_dump call
521 post_full_gc_dump(NULL); // do any post full gc dumps
522 }
523
524 if (PrintGCDetails) {
525 print_heap_change(gch_prev_used);
526
527 // Print metaspace info for full GC with PrintGCDetails flag.
528 if (complete) {
529 MetaspaceAux::print_metaspace_change(metadata_prev_used);
530 }
531 }
532
533 // Adjust generation sizes.
534 if (max_level_collected == 1) {
535 _old_gen->compute_new_size();
536 }
537 _young_gen->compute_new_size();
538
539 if (complete) {
540 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
541 ClassLoaderDataGraph::purge();
542 MetaspaceAux::verify_metrics();
543 // Resize the metaspace capacity after full collections
544 MetaspaceGC::compute_new_size();
545 update_full_collections_completed();
546 }
547
548 // Track memory usage and detect low memory after GC finishes
549 MemoryService::track_memory_usage();
550
551 gc_epilogue(complete);
552
553 if (must_restore_marks_for_biased_locking) {
554 BiasedLocking::restore_marks();
555 }
556 }
557
574 void GenCollectedHeap::
575 gen_process_roots(int level,
576 bool younger_gens_as_roots,
577 bool activate_scope,
578 SharedHeap::ScanningOption so,
579 OopsInGenClosure* not_older_gens,
580 OopsInGenClosure* weak_roots,
581 OopsInGenClosure* older_gens,
582 CLDClosure* cld_closure,
583 CLDClosure* weak_cld_closure,
584 CodeBlobClosure* code_closure) {
585
586 // General roots.
587 SharedHeap::process_roots(activate_scope, so,
588 not_older_gens, weak_roots,
589 cld_closure, weak_cld_closure,
590 code_closure);
591
592 if (younger_gens_as_roots) {
593 if (!_gen_process_roots_tasks->is_task_claimed(GCH_PS_younger_gens)) {
594 if (level == 1) {
595 not_older_gens->set_generation(_young_gen);
596 _young_gen->oop_iterate(not_older_gens);
597 }
598 not_older_gens->reset_generation();
599 }
600 }
601 // When collection is parallel, all threads get to cooperate to do
602 // older-gen scanning.
603 if (level == 0) {
604 older_gens->set_generation(_old_gen);
605 rem_set()->younger_refs_iterate(_old_gen, older_gens);
606 older_gens->reset_generation();
607 }
608
609 _gen_process_roots_tasks->all_tasks_completed();
610 }
611
612 void GenCollectedHeap::
613 gen_process_roots(int level,
614 bool younger_gens_as_roots,
615 bool activate_scope,
616 SharedHeap::ScanningOption so,
617 bool only_strong_roots,
618 OopsInGenClosure* not_older_gens,
619 OopsInGenClosure* older_gens,
620 CLDClosure* cld_closure) {
621
622 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
623
624 bool is_moving_collection = false;
625 if (level == 0 || is_adjust_phase) {
626 // young collections are always moving
627 is_moving_collection = true;
628 }
629
630 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
631 CodeBlobClosure* code_closure = &mark_code_closure;
632
633 gen_process_roots(level,
634 younger_gens_as_roots,
635 activate_scope, so,
636 not_older_gens, only_strong_roots ? NULL : not_older_gens,
637 older_gens,
638 cld_closure, only_strong_roots ? NULL : cld_closure,
639 code_closure);
640
641 }
642
643 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
644 SharedHeap::process_weak_roots(root_closure);
645 // "Local" "weak" refs
646 _young_gen->ref_processor()->weak_oops_do(root_closure);
647 _old_gen->ref_processor()->weak_oops_do(root_closure);
648 }
649
650 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
651 void GenCollectedHeap:: \
652 oop_since_save_marks_iterate(int level, \
653 OopClosureType* cur, \
654 OopClosureType* older) { \
655 if (level == 0) { \
656 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
657 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
658 } else { \
659 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
660 } \
661 }
662
663 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
664
665 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
666
667 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
668 if (level == 0 && !_young_gen->no_allocs_since_save_marks()) {
669 return false;
670 }
671 return _old_gen->no_allocs_since_save_marks();
672 }
673
674 bool GenCollectedHeap::supports_inline_contig_alloc() const {
675 return _young_gen->supports_inline_contig_alloc();
676 }
677
678 HeapWord** GenCollectedHeap::top_addr() const {
679 return _young_gen->top_addr();
680 }
681
682 HeapWord** GenCollectedHeap::end_addr() const {
683 return _young_gen->end_addr();
684 }
685
686 // public collection interfaces
687
688 void GenCollectedHeap::collect(GCCause::Cause cause) {
689 if (should_do_concurrent_full_gc(cause)) {
690 #if INCLUDE_ALL_GCS
691 // mostly concurrent full collection
692 collect_mostly_concurrent(cause);
693 #else // INCLUDE_ALL_GCS
694 ShouldNotReachHere();
695 #endif // INCLUDE_ALL_GCS
696 } else if (cause == GCCause::_wb_young_gc) {
697 // minor collection for WhiteBox API
698 collect(cause, 0);
699 } else {
700 #ifdef ASSERT
701 if (cause == GCCause::_scavenge_alot) {
702 // minor collection only
703 collect(cause, 0);
726 }
727
728 // this is the private collection interface
729 // The Heap_lock is expected to be held on entry.
730
731 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
732 // Read the GC count while holding the Heap_lock
733 unsigned int gc_count_before = total_collections();
734 unsigned int full_gc_count_before = total_full_collections();
735 {
736 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
737 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
738 cause, max_level);
739 VMThread::execute(&op);
740 }
741 }
742
743 #if INCLUDE_ALL_GCS
744 bool GenCollectedHeap::create_cms_collector() {
745
746 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
747 "Unexpected generation kinds");
748 // Skip two header words in the block content verification
749 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
750 CMSCollector* collector = new CMSCollector(
751 (ConcurrentMarkSweepGeneration*)_old_gen,
752 _rem_set->as_CardTableRS(),
753 (ConcurrentMarkSweepPolicy*) collector_policy());
754
755 if (collector == NULL || !collector->completed_initialization()) {
756 if (collector) {
757 delete collector; // Be nice in embedded situation
758 }
759 vm_shutdown_during_initialization("Could not create CMS collector");
760 return false;
761 }
762 return true; // success
763 }
764
765 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
766 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
767
768 MutexLocker ml(Heap_lock);
769 // Read the GC counts while holding the Heap_lock
770 unsigned int full_gc_count_before = total_full_collections();
771 unsigned int gc_count_before = total_collections();
798 local_max_level /* max_level */);
799 // Hack XXX FIX ME !!!
800 // A scavenge may not have been attempted, or may have
801 // been attempted and failed, because the old gen was too full
802 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
803 incremental_collection_will_fail(false /* don't consult_young */)) {
804 if (PrintGCDetails) {
805 gclog_or_tty->print_cr("GC locker: Trying a full collection "
806 "because scavenge failed");
807 }
808 // This time allow the old gen to be collected as well
809 do_collection(true /* full */,
810 clear_all_soft_refs /* clear_all_soft_refs */,
811 0 /* size */,
812 false /* is_tlab */,
813 n_gens() - 1 /* max_level */);
814 }
815 }
816
817 bool GenCollectedHeap::is_in_young(oop p) {
818 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
819 assert(result == _young_gen->is_in_reserved(p),
820 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
821 return result;
822 }
823
824 // Returns "TRUE" iff "p" points into the committed areas of the heap.
825 bool GenCollectedHeap::is_in(const void* p) const {
826 #ifndef ASSERT
827 guarantee(VerifyBeforeGC ||
828 VerifyDuringGC ||
829 VerifyBeforeExit ||
830 VerifyDuringStartup ||
831 PrintAssembly ||
832 tty->count() != 0 || // already printing
833 VerifyAfterGC ||
834 VMError::fatal_error_in_progress(), "too expensive");
835
836 #endif
837 // This might be sped up with a cache of the last generation that
838 // answered yes.
839 if (_young_gen->is_in(p) || _old_gen->is_in(p)) {
840 return true;
841 }
842 // Otherwise...
843 return false;
844 }
845
846 #ifdef ASSERT
847 // Don't implement this by using is_in_young(). This method is used
848 // in some cases to check that is_in_young() is correct.
849 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
850 assert(is_in_reserved(p) || p == NULL,
851 "Does not work if address is non-null and outside of the heap");
852 return p < _young_gen->reserved().end() && p != NULL;
853 }
854 #endif
855
856 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
857 _young_gen->oop_iterate(cl);
858 _old_gen->oop_iterate(cl);
859 }
860
861 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
862 _young_gen->object_iterate(cl);
863 _old_gen->object_iterate(cl);
864 }
865
866 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
867 _young_gen->safe_object_iterate(cl);
868 _old_gen->safe_object_iterate(cl);
869 }
870
871 Space* GenCollectedHeap::space_containing(const void* addr) const {
872 Space* res = _young_gen->space_containing(addr);
873 if (res != NULL) {
874 return res;
875 }
876 res = _old_gen->space_containing(addr);
877 assert(res != NULL, "Could not find containing space");
878 return res;
879 }
880
881 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
882 assert(is_in_reserved(addr), "block_start of address outside of heap");
883 if (_young_gen->is_in_reserved(addr)) {
884 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
885 return _young_gen->block_start(addr);
886 }
887
888 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
889 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
890 return _old_gen->block_start(addr);
891 }
892
893 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
894 assert(is_in_reserved(addr), "block_size of address outside of heap");
895 if (_young_gen->is_in_reserved(addr)) {
896 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
897 return _young_gen->block_size(addr);
898 }
899
900 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
901 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
902 return _old_gen->block_size(addr);
903 }
904
905 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
906 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
907 assert(block_start(addr) == addr, "addr must be a block start");
908 if (_young_gen->is_in_reserved(addr)) {
909 return _young_gen->block_is_obj(addr);
910 }
911
912 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
913 return _old_gen->block_is_obj(addr);
914 }
915
916 bool GenCollectedHeap::supports_tlab_allocation() const {
917 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
918 return _young_gen->supports_tlab_allocation();
919 }
920
921 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
922 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
923 if (_young_gen->supports_tlab_allocation()) {
924 return _young_gen->tlab_capacity();
925 }
926 return 0;
927 }
928
929 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
930 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
931 if (_young_gen->supports_tlab_allocation()) {
932 return _young_gen->tlab_used();
933 }
934 return 0;
935 }
936
937 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
938 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
939 if (_young_gen->supports_tlab_allocation()) {
940 return _young_gen->unsafe_max_tlab_alloc();
941 }
942 return 0;
943 }
944
945 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
946 bool gc_overhead_limit_was_exceeded;
947 return collector_policy()->mem_allocate_work(size /* size */,
948 true /* is_tlab */,
949 &gc_overhead_limit_was_exceeded);
950 }
951
952 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
953 // from the list headed by "*prev_ptr".
954 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
955 bool first = true;
956 size_t min_size = 0; // "first" makes this conceptually infinite.
957 ScratchBlock **smallest_ptr, *smallest;
958 ScratchBlock *cur = *prev_ptr;
959 while (cur) {
960 assert(*prev_ptr == cur, "just checking");
961 if (first || cur->num_words < min_size) {
962 smallest_ptr = prev_ptr;
971 *smallest_ptr = smallest->next;
972 return smallest;
973 }
974
975 // Sort the scratch block list headed by res into decreasing size order,
976 // and set "res" to the result.
977 static void sort_scratch_list(ScratchBlock*& list) {
978 ScratchBlock* sorted = NULL;
979 ScratchBlock* unsorted = list;
980 while (unsorted) {
981 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
982 smallest->next = sorted;
983 sorted = smallest;
984 }
985 list = sorted;
986 }
987
988 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
989 size_t max_alloc_words) {
990 ScratchBlock* res = NULL;
991 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
992 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
993 sort_scratch_list(res);
994 return res;
995 }
996
997 void GenCollectedHeap::release_scratch() {
998 _young_gen->reset_scratch();
999 _old_gen->reset_scratch();
1000 }
1001
1002 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1003 void do_generation(Generation* gen) {
1004 gen->prepare_for_verify();
1005 }
1006 };
1007
1008 void GenCollectedHeap::prepare_for_verify() {
1009 ensure_parsability(false); // no need to retire TLABs
1010 GenPrepareForVerifyClosure blk;
1011 generation_iterate(&blk, false);
1012 }
1013
1014 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1015 bool old_to_young) {
1016 if (old_to_young) {
1017 cl->do_generation(_old_gen);
1018 cl->do_generation(_young_gen);
1019 } else {
1020 cl->do_generation(_young_gen);
1021 cl->do_generation(_old_gen);
1022 }
1023 }
1024
1025 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1026 _young_gen->space_iterate(cl, true);
1027 _old_gen->space_iterate(cl, true);
1028 }
1029
1030 bool GenCollectedHeap::is_maximal_no_gc() const {
1031 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1032 }
1033
1034 void GenCollectedHeap::save_marks() {
1035 _young_gen->save_marks();
1036 _old_gen->save_marks();
1037 }
1038
1039 GenCollectedHeap* GenCollectedHeap::heap() {
1040 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1041 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1042 return _gch;
1043 }
1044
1045
1046 void GenCollectedHeap::prepare_for_compaction() {
1047 guarantee(_n_gens = 2, "Wrong number of generations");
1048 Generation* old_gen = _old_gen;
1049 // Start by compacting into same gen.
1050 CompactPoint cp(old_gen);
1051 old_gen->prepare_for_compaction(&cp);
1052 Generation* young_gen = _young_gen;
1053 young_gen->prepare_for_compaction(&cp);
1054 }
1055
1056 GCStats* GenCollectedHeap::gc_stats(int level) const {
1057 if (level == 0) {
1058 return _young_gen->gc_stats();
1059 } else {
1060 return _old_gen->gc_stats();
1061 }
1062 }
1063
1064 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1065 if (!silent) {
1066 gclog_or_tty->print("%s", _old_gen->name());
1067 gclog_or_tty->print(" ");
1068 }
1069 _old_gen->verify();
1070
1071 if (!silent) {
1072 gclog_or_tty->print("%s", _young_gen->name());
1073 gclog_or_tty->print(" ");
1074 }
1075 _young_gen->verify();
1076
1077 if (!silent) {
1078 gclog_or_tty->print("remset ");
1079 }
1080 rem_set()->verify();
1081 }
1082
1083 void GenCollectedHeap::print_on(outputStream* st) const {
1084 _young_gen->print_on(st);
1085 _old_gen->print_on(st);
1086 MetaspaceAux::print_on(st);
1087 }
1088
1089 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1090 if (workers() != NULL) {
1091 workers()->threads_do(tc);
1092 }
1093 #if INCLUDE_ALL_GCS
1094 if (UseConcMarkSweepGC) {
1095 ConcurrentMarkSweepThread::threads_do(tc);
1096 }
1097 #endif // INCLUDE_ALL_GCS
1098 }
1099
1100 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1101 #if INCLUDE_ALL_GCS
1102 if (UseConcMarkSweepGC) {
1103 workers()->print_worker_threads_on(st);
1104 ConcurrentMarkSweepThread::print_all_on(st);
1105 }
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