113 ReservedSpace heap_rs;
114
115 size_t heap_alignment = collector_policy()->heap_alignment();
116
117 heap_address = allocate(heap_alignment, &total_reserved,
118 &n_covered_regions, &heap_rs);
119
120 if (!heap_rs.is_reserved()) {
121 vm_shutdown_during_initialization(
122 "Could not reserve enough space for object heap");
123 return JNI_ENOMEM;
124 }
125
126 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
127
128 _rem_set = collector_policy()->create_rem_set(reserved_region(), n_covered_regions);
129 set_barrier_set(rem_set()->bs());
130
131 _gch = this;
132
133 for (i = 0; i < _n_gens; i++) {
134 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(), false, false);
135 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
136 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
137 }
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
153 char* GenCollectedHeap::allocate(size_t alignment,
154 size_t* _total_reserved,
155 int* _n_covered_regions,
156 ReservedSpace* heap_rs){
157 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
158 "the maximum representable size";
159
160 // Now figure out the total size.
161 size_t total_reserved = 0;
162 int n_covered_regions = 0;
163 const size_t pageSize = UseLargePages ?
164 os::large_page_size() : os::vm_page_size();
165
166 assert(alignment % pageSize == 0, "Must be");
167
168 for (int i = 0; i < _n_gens; i++) {
169 total_reserved += _gen_specs[i]->max_size();
170 if (total_reserved < _gen_specs[i]->max_size()) {
171 vm_exit_during_initialization(overflow_msg);
172 }
173 n_covered_regions += _gen_specs[i]->n_covered_regions();
174 }
175 assert(total_reserved % alignment == 0,
176 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
177 SIZE_FORMAT, total_reserved, alignment));
178
179 // Needed until the cardtable is fixed to have the right number
180 // of covered regions.
181 n_covered_regions += 2;
182
183 *_total_reserved = total_reserved;
184 *_n_covered_regions = n_covered_regions;
185
186 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
187 return heap_rs->base();
188 }
189
190
191 void GenCollectedHeap::post_initialize() {
192 SharedHeap::post_initialize();
193 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
194 guarantee(policy->is_generation_policy(), "Illegal policy type");
195 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
196 assert(def_new_gen->kind() == Generation::DefNew ||
197 def_new_gen->kind() == Generation::ParNew,
198 "Wrong generation kind");
199
200 Generation* old_gen = get_gen(1);
201 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
202 old_gen->kind() == Generation::MarkSweepCompact,
203 "Wrong generation kind");
204
205 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
206 old_gen->capacity(),
207 def_new_gen->from()->capacity());
208 policy->initialize_gc_policy_counters();
209 }
210
211 void GenCollectedHeap::ref_processing_init() {
212 SharedHeap::ref_processing_init();
213 for (int i = 0; i < _n_gens; i++) {
214 _gens[i]->ref_processor_init();
215 }
216 }
217
218 size_t GenCollectedHeap::capacity() const {
219 size_t res = 0;
220 for (int i = 0; i < _n_gens; i++) {
221 res += _gens[i]->capacity();
222 }
223 return res;
224 }
225
226 size_t GenCollectedHeap::used() const {
227 size_t res = 0;
228 for (int i = 0; i < _n_gens; i++) {
229 res += _gens[i]->used();
230 }
231 return res;
232 }
233
234 // Save the "used_region" for generations level and lower.
235 void GenCollectedHeap::save_used_regions(int level) {
236 assert(level < _n_gens, "Illegal level parameter");
237 for (int i = level; i >= 0; i--) {
238 _gens[i]->save_used_region();
239 }
240 }
241
242 size_t GenCollectedHeap::max_capacity() const {
243 size_t res = 0;
244 for (int i = 0; i < _n_gens; i++) {
245 res += _gens[i]->max_capacity();
246 }
247 return res;
248 }
249
250 // Update the _full_collections_completed counter
251 // at the end of a stop-world full GC.
252 unsigned int GenCollectedHeap::update_full_collections_completed() {
253 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
254 assert(_full_collections_completed <= _total_full_collections,
255 "Can't complete more collections than were started");
256 _full_collections_completed = _total_full_collections;
257 ml.notify_all();
258 return _full_collections_completed;
259 }
260
261 // Update the _full_collections_completed counter, as appropriate,
262 // at the end of a concurrent GC cycle. Note the conditional update
263 // below to allow this method to be called by a concurrent collector
264 // without synchronizing in any manner with the VM thread (which
265 // may already have initiated a STW full collection "concurrently").
266 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
267 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
291 // higher than we are prepared to pay for such rudimentary debugging
292 // support.
293 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
294 size_t size) {
295 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
296 // We are asked to check a size in HeapWords,
297 // but the memory is mangled in juint words.
298 juint* start = (juint*) (addr + skip_header_HeapWords());
299 juint* end = (juint*) (addr + size);
300 for (juint* slot = start; slot < end; slot += 1) {
301 assert(*slot == badHeapWordVal,
302 "Found non badHeapWordValue in pre-allocation check");
303 }
304 }
305 }
306 #endif
307
308 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
309 bool is_tlab,
310 bool first_only) {
311 HeapWord* res;
312 for (int i = 0; i < _n_gens; i++) {
313 if (_gens[i]->should_allocate(size, is_tlab)) {
314 res = _gens[i]->allocate(size, is_tlab);
315 if (res != NULL) return res;
316 else if (first_only) break;
317 }
318 }
319 // Otherwise...
320 return NULL;
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::do_collection(bool full,
341 bool clear_all_soft_refs,
342 size_t size,
343 bool is_tlab,
344 int max_level) {
345 bool prepared_for_verification = false;
346 ResourceMark rm;
347 DEBUG_ONLY(Thread* my_thread = Thread::current();)
348
349 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
350 assert(my_thread->is_VM_thread() ||
351 my_thread->is_ConcurrentGC_thread(),
352 "incorrect thread type capability");
353 assert(Heap_lock->is_locked(),
354 "the requesting thread should have the Heap_lock");
355 guarantee(!is_gc_active(), "collection is not reentrant");
356 assert(max_level < n_gens(), "sanity check");
357
358 if (GC_locker::check_active_before_gc()) {
359 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
360 }
361
362 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
363 collector_policy()->should_clear_all_soft_refs();
364
365 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
366
367 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
368
369 print_heap_before_gc();
370
371 {
372 FlagSetting fl(_is_gc_active, true);
373
374 bool complete = full && (max_level == (n_gens()-1));
375 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
376 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
377 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
378 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
379 // so we can assume here that the next GC id is what we want.
380 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
381
382 gc_prologue(complete);
383 increment_total_collections(complete);
384
385 size_t gch_prev_used = used();
386
387 int starting_level = 0;
388 if (full) {
389 // Search for the oldest generation which will collect all younger
390 // generations, and start collection loop there.
391 for (int i = max_level; i >= 0; i--) {
392 if (_gens[i]->full_collects_younger_generations()) {
393 starting_level = i;
394 break;
395 }
396 }
397 }
398
399 bool must_restore_marks_for_biased_locking = false;
400
401 int max_level_collected = starting_level;
402 for (int i = starting_level; i <= max_level; i++) {
403 if (_gens[i]->should_collect(full, size, is_tlab)) {
404 if (i == n_gens() - 1) { // a major collection is to happen
405 if (!complete) {
406 // The full_collections increment was missed above.
407 increment_total_full_collections();
408 }
409 pre_full_gc_dump(NULL); // do any pre full gc dumps
410 }
411 // Timer for individual generations. Last argument is false: no CR
412 // FIXME: We should try to start the timing earlier to cover more of the GC pause
413 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
414 // so we can assume here that the next GC id is what we want.
415 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL, GCId::peek());
416 TraceCollectorStats tcs(_gens[i]->counters());
417 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
418
419 size_t prev_used = _gens[i]->used();
420 _gens[i]->stat_record()->invocations++;
421 _gens[i]->stat_record()->accumulated_time.start();
422
423 // Must be done anew before each collection because
424 // a previous collection will do mangling and will
425 // change top of some spaces.
426 record_gen_tops_before_GC();
427
428 if (PrintGC && Verbose) {
429 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
430 i,
431 _gens[i]->stat_record()->invocations,
432 size*HeapWordSize);
433 }
434
435 if (VerifyBeforeGC && i >= VerifyGCLevel &&
436 total_collections() >= VerifyGCStartAt) {
437 HandleMark hm; // Discard invalid handles created during verification
438 if (!prepared_for_verification) {
439 prepare_for_verify();
440 prepared_for_verification = true;
441 }
442 Universe::verify(" VerifyBeforeGC:");
443 }
444 COMPILER2_PRESENT(DerivedPointerTable::clear());
445
446 if (!must_restore_marks_for_biased_locking &&
447 _gens[i]->performs_in_place_marking()) {
448 // We perform this mark word preservation work lazily
449 // because it's only at this point that we know whether we
450 // absolutely have to do it; we want to avoid doing it for
451 // scavenge-only collections where it's unnecessary
452 must_restore_marks_for_biased_locking = true;
453 BiasedLocking::preserve_marks();
454 }
455
456 // Do collection work
457 {
458 // Note on ref discovery: For what appear to be historical reasons,
459 // GCH enables and disabled (by enqueing) refs discovery.
460 // In the future this should be moved into the generation's
461 // collect method so that ref discovery and enqueueing concerns
462 // are local to a generation. The collect method could return
463 // an appropriate indication in the case that notification on
464 // the ref lock was needed. This will make the treatment of
465 // weak refs more uniform (and indeed remove such concerns
466 // from GCH). XXX
467
468 HandleMark hm; // Discard invalid handles created during gc
469 save_marks(); // save marks for all gens
470 // We want to discover references, but not process them yet.
471 // This mode is disabled in process_discovered_references if the
472 // generation does some collection work, or in
473 // enqueue_discovered_references if the generation returns
474 // without doing any work.
475 ReferenceProcessor* rp = _gens[i]->ref_processor();
476 // If the discovery of ("weak") refs in this generation is
477 // atomic wrt other collectors in this configuration, we
478 // are guaranteed to have empty discovered ref lists.
479 if (rp->discovery_is_atomic()) {
480 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
481 rp->setup_policy(do_clear_all_soft_refs);
482 } else {
483 // collect() below will enable discovery as appropriate
484 }
485 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
486 if (!rp->enqueuing_is_done()) {
487 rp->enqueue_discovered_references();
488 } else {
489 rp->set_enqueuing_is_done(false);
490 }
491 rp->verify_no_references_recorded();
492 }
493 max_level_collected = i;
494
495 // Determine if allocation request was met.
496 if (size > 0) {
497 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
498 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
499 size = 0;
500 }
501 }
502 }
503
504 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
505
506 _gens[i]->stat_record()->accumulated_time.stop();
507
508 update_gc_stats(i, full);
509
510 if (VerifyAfterGC && i >= VerifyGCLevel &&
511 total_collections() >= VerifyGCStartAt) {
512 HandleMark hm; // Discard invalid handles created during verification
513 Universe::verify(" VerifyAfterGC:");
514 }
515
516 if (PrintGCDetails) {
517 gclog_or_tty->print(":");
518 _gens[i]->print_heap_change(prev_used);
519 }
520 }
521 }
522
523 // Update "complete" boolean wrt what actually transpired --
524 // for instance, a promotion failure could have led to
525 // a whole heap collection.
526 complete = complete || (max_level_collected == n_gens() - 1);
527
528 if (complete) { // We did a "major" collection
529 // FIXME: See comment at pre_full_gc_dump call
530 post_full_gc_dump(NULL); // do any post full gc dumps
531 }
532
533 if (PrintGCDetails) {
534 print_heap_change(gch_prev_used);
535
536 // Print metaspace info for full GC with PrintGCDetails flag.
537 if (complete) {
538 MetaspaceAux::print_metaspace_change(metadata_prev_used);
539 }
540 }
541
542 for (int j = max_level_collected; j >= 0; j -= 1) {
543 // Adjust generation sizes.
544 _gens[j]->compute_new_size();
545 }
546
547 if (complete) {
548 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
549 ClassLoaderDataGraph::purge();
550 MetaspaceAux::verify_metrics();
551 // Resize the metaspace capacity after full collections
552 MetaspaceGC::compute_new_size();
553 update_full_collections_completed();
554 }
555
556 // Track memory usage and detect low memory after GC finishes
557 MemoryService::track_memory_usage();
558
559 gc_epilogue(complete);
560
561 if (must_restore_marks_for_biased_locking) {
562 BiasedLocking::restore_marks();
563 }
564 }
565
582 void GenCollectedHeap::
583 gen_process_roots(int level,
584 bool younger_gens_as_roots,
585 bool activate_scope,
586 SharedHeap::ScanningOption so,
587 OopsInGenClosure* not_older_gens,
588 OopsInGenClosure* weak_roots,
589 OopsInGenClosure* older_gens,
590 CLDClosure* cld_closure,
591 CLDClosure* weak_cld_closure,
592 CodeBlobClosure* code_closure) {
593
594 // General roots.
595 SharedHeap::process_roots(activate_scope, so,
596 not_older_gens, weak_roots,
597 cld_closure, weak_cld_closure,
598 code_closure);
599
600 if (younger_gens_as_roots) {
601 if (!_gen_process_roots_tasks->is_task_claimed(GCH_PS_younger_gens)) {
602 for (int i = 0; i < level; i++) {
603 not_older_gens->set_generation(_gens[i]);
604 _gens[i]->oop_iterate(not_older_gens);
605 }
606 not_older_gens->reset_generation();
607 }
608 }
609 // When collection is parallel, all threads get to cooperate to do
610 // older-gen scanning.
611 for (int i = level+1; i < _n_gens; i++) {
612 older_gens->set_generation(_gens[i]);
613 rem_set()->younger_refs_iterate(_gens[i], older_gens);
614 older_gens->reset_generation();
615 }
616
617 _gen_process_roots_tasks->all_tasks_completed();
618 }
619
620 void GenCollectedHeap::
621 gen_process_roots(int level,
622 bool younger_gens_as_roots,
623 bool activate_scope,
624 SharedHeap::ScanningOption so,
625 bool only_strong_roots,
626 OopsInGenClosure* not_older_gens,
627 OopsInGenClosure* older_gens,
628 CLDClosure* cld_closure) {
629
630 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
631
632 bool is_moving_collection = false;
633 if (level == 0 || is_adjust_phase) {
634 // young collections are always moving
635 is_moving_collection = true;
636 }
637
638 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
639 CodeBlobClosure* code_closure = &mark_code_closure;
640
641 gen_process_roots(level,
642 younger_gens_as_roots,
643 activate_scope, so,
644 not_older_gens, only_strong_roots ? NULL : not_older_gens,
645 older_gens,
646 cld_closure, only_strong_roots ? NULL : cld_closure,
647 code_closure);
648
649 }
650
651 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
652 SharedHeap::process_weak_roots(root_closure);
653 // "Local" "weak" refs
654 for (int i = 0; i < _n_gens; i++) {
655 _gens[i]->ref_processor()->weak_oops_do(root_closure);
656 }
657 }
658
659 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
660 void GenCollectedHeap:: \
661 oop_since_save_marks_iterate(int level, \
662 OopClosureType* cur, \
663 OopClosureType* older) { \
664 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
665 for (int i = level+1; i < n_gens(); i++) { \
666 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
667 } \
668 }
669
670 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
671
672 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
673
674 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
675 for (int i = level; i < _n_gens; i++) {
676 if (!_gens[i]->no_allocs_since_save_marks()) return false;
677 }
678 return true;
679 }
680
681 bool GenCollectedHeap::supports_inline_contig_alloc() const {
682 return _gens[0]->supports_inline_contig_alloc();
683 }
684
685 HeapWord** GenCollectedHeap::top_addr() const {
686 return _gens[0]->top_addr();
687 }
688
689 HeapWord** GenCollectedHeap::end_addr() const {
690 return _gens[0]->end_addr();
691 }
692
693 // public collection interfaces
694
695 void GenCollectedHeap::collect(GCCause::Cause cause) {
696 if (should_do_concurrent_full_gc(cause)) {
697 #if INCLUDE_ALL_GCS
698 // mostly concurrent full collection
699 collect_mostly_concurrent(cause);
700 #else // INCLUDE_ALL_GCS
701 ShouldNotReachHere();
702 #endif // INCLUDE_ALL_GCS
703 } else if (cause == GCCause::_wb_young_gc) {
704 // minor collection for WhiteBox API
705 collect(cause, 0);
706 } else {
707 #ifdef ASSERT
708 if (cause == GCCause::_scavenge_alot) {
709 // minor collection only
710 collect(cause, 0);
733 }
734
735 // this is the private collection interface
736 // The Heap_lock is expected to be held on entry.
737
738 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
739 // Read the GC count while holding the Heap_lock
740 unsigned int gc_count_before = total_collections();
741 unsigned int full_gc_count_before = total_full_collections();
742 {
743 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
744 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
745 cause, max_level);
746 VMThread::execute(&op);
747 }
748 }
749
750 #if INCLUDE_ALL_GCS
751 bool GenCollectedHeap::create_cms_collector() {
752
753 assert(_gens[1]->kind() == Generation::ConcurrentMarkSweep,
754 "Unexpected generation kinds");
755 // Skip two header words in the block content verification
756 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
757 CMSCollector* collector = new CMSCollector(
758 (ConcurrentMarkSweepGeneration*)_gens[1],
759 _rem_set->as_CardTableRS(),
760 (ConcurrentMarkSweepPolicy*) collector_policy());
761
762 if (collector == NULL || !collector->completed_initialization()) {
763 if (collector) {
764 delete collector; // Be nice in embedded situation
765 }
766 vm_shutdown_during_initialization("Could not create CMS collector");
767 return false;
768 }
769 return true; // success
770 }
771
772 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
773 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
774
775 MutexLocker ml(Heap_lock);
776 // Read the GC counts while holding the Heap_lock
777 unsigned int full_gc_count_before = total_full_collections();
778 unsigned int gc_count_before = total_collections();
805 local_max_level /* max_level */);
806 // Hack XXX FIX ME !!!
807 // A scavenge may not have been attempted, or may have
808 // been attempted and failed, because the old gen was too full
809 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
810 incremental_collection_will_fail(false /* don't consult_young */)) {
811 if (PrintGCDetails) {
812 gclog_or_tty->print_cr("GC locker: Trying a full collection "
813 "because scavenge failed");
814 }
815 // This time allow the old gen to be collected as well
816 do_collection(true /* full */,
817 clear_all_soft_refs /* clear_all_soft_refs */,
818 0 /* size */,
819 false /* is_tlab */,
820 n_gens() - 1 /* max_level */);
821 }
822 }
823
824 bool GenCollectedHeap::is_in_young(oop p) {
825 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
826 assert(result == _gens[0]->is_in_reserved(p),
827 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
828 return result;
829 }
830
831 // Returns "TRUE" iff "p" points into the committed areas of the heap.
832 bool GenCollectedHeap::is_in(const void* p) const {
833 #ifndef ASSERT
834 guarantee(VerifyBeforeGC ||
835 VerifyDuringGC ||
836 VerifyBeforeExit ||
837 VerifyDuringStartup ||
838 PrintAssembly ||
839 tty->count() != 0 || // already printing
840 VerifyAfterGC ||
841 VMError::fatal_error_in_progress(), "too expensive");
842
843 #endif
844 // This might be sped up with a cache of the last generation that
845 // answered yes.
846 for (int i = 0; i < _n_gens; i++) {
847 if (_gens[i]->is_in(p)) return true;
848 }
849 // Otherwise...
850 return false;
851 }
852
853 #ifdef ASSERT
854 // Don't implement this by using is_in_young(). This method is used
855 // in some cases to check that is_in_young() is correct.
856 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
857 assert(is_in_reserved(p) || p == NULL,
858 "Does not work if address is non-null and outside of the heap");
859 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
860 }
861 #endif
862
863 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
864 for (int i = 0; i < _n_gens; i++) {
865 _gens[i]->oop_iterate(cl);
866 }
867 }
868
869 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
870 for (int i = 0; i < _n_gens; i++) {
871 _gens[i]->object_iterate(cl);
872 }
873 }
874
875 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
876 for (int i = 0; i < _n_gens; i++) {
877 _gens[i]->safe_object_iterate(cl);
878 }
879 }
880
881 Space* GenCollectedHeap::space_containing(const void* addr) const {
882 for (int i = 0; i < _n_gens; i++) {
883 Space* res = _gens[i]->space_containing(addr);
884 if (res != NULL) return res;
885 }
886 // Otherwise...
887 assert(false, "Could not find containing space");
888 return NULL;
889 }
890
891
892 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
893 assert(is_in_reserved(addr), "block_start of address outside of heap");
894 for (int i = 0; i < _n_gens; i++) {
895 if (_gens[i]->is_in_reserved(addr)) {
896 assert(_gens[i]->is_in(addr),
897 "addr should be in allocated part of generation");
898 return _gens[i]->block_start(addr);
899 }
900 }
901 assert(false, "Some generation should contain the address");
902 return NULL;
903 }
904
905 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
906 assert(is_in_reserved(addr), "block_size of address outside of heap");
907 for (int i = 0; i < _n_gens; i++) {
908 if (_gens[i]->is_in_reserved(addr)) {
909 assert(_gens[i]->is_in(addr),
910 "addr should be in allocated part of generation");
911 return _gens[i]->block_size(addr);
912 }
913 }
914 assert(false, "Some generation should contain the address");
915 return 0;
916 }
917
918 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
919 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
920 assert(block_start(addr) == addr, "addr must be a block start");
921 for (int i = 0; i < _n_gens; i++) {
922 if (_gens[i]->is_in_reserved(addr)) {
923 return _gens[i]->block_is_obj(addr);
924 }
925 }
926 assert(false, "Some generation should contain the address");
927 return false;
928 }
929
930 bool GenCollectedHeap::supports_tlab_allocation() const {
931 for (int i = 0; i < _n_gens; i += 1) {
932 if (_gens[i]->supports_tlab_allocation()) {
933 return true;
934 }
935 }
936 return false;
937 }
938
939 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
940 size_t result = 0;
941 for (int i = 0; i < _n_gens; i += 1) {
942 if (_gens[i]->supports_tlab_allocation()) {
943 result += _gens[i]->tlab_capacity();
944 }
945 }
946 return result;
947 }
948
949 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
950 size_t result = 0;
951 for (int i = 0; i < _n_gens; i += 1) {
952 if (_gens[i]->supports_tlab_allocation()) {
953 result += _gens[i]->tlab_used();
954 }
955 }
956 return result;
957 }
958
959 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
960 size_t result = 0;
961 for (int i = 0; i < _n_gens; i += 1) {
962 if (_gens[i]->supports_tlab_allocation()) {
963 result += _gens[i]->unsafe_max_tlab_alloc();
964 }
965 }
966 return result;
967 }
968
969 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
970 bool gc_overhead_limit_was_exceeded;
971 return collector_policy()->mem_allocate_work(size /* size */,
972 true /* is_tlab */,
973 &gc_overhead_limit_was_exceeded);
974 }
975
976 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
977 // from the list headed by "*prev_ptr".
978 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
979 bool first = true;
980 size_t min_size = 0; // "first" makes this conceptually infinite.
981 ScratchBlock **smallest_ptr, *smallest;
982 ScratchBlock *cur = *prev_ptr;
983 while (cur) {
984 assert(*prev_ptr == cur, "just checking");
985 if (first || cur->num_words < min_size) {
986 smallest_ptr = prev_ptr;
995 *smallest_ptr = smallest->next;
996 return smallest;
997 }
998
999 // Sort the scratch block list headed by res into decreasing size order,
1000 // and set "res" to the result.
1001 static void sort_scratch_list(ScratchBlock*& list) {
1002 ScratchBlock* sorted = NULL;
1003 ScratchBlock* unsorted = list;
1004 while (unsorted) {
1005 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1006 smallest->next = sorted;
1007 sorted = smallest;
1008 }
1009 list = sorted;
1010 }
1011
1012 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1013 size_t max_alloc_words) {
1014 ScratchBlock* res = NULL;
1015 for (int i = 0; i < _n_gens; i++) {
1016 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1017 }
1018 sort_scratch_list(res);
1019 return res;
1020 }
1021
1022 void GenCollectedHeap::release_scratch() {
1023 for (int i = 0; i < _n_gens; i++) {
1024 _gens[i]->reset_scratch();
1025 }
1026 }
1027
1028 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1029 void do_generation(Generation* gen) {
1030 gen->prepare_for_verify();
1031 }
1032 };
1033
1034 void GenCollectedHeap::prepare_for_verify() {
1035 ensure_parsability(false); // no need to retire TLABs
1036 GenPrepareForVerifyClosure blk;
1037 generation_iterate(&blk, false);
1038 }
1039
1040
1041 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1042 bool old_to_young) {
1043 if (old_to_young) {
1044 for (int i = _n_gens-1; i >= 0; i--) {
1045 cl->do_generation(_gens[i]);
1046 }
1047 } else {
1048 for (int i = 0; i < _n_gens; i++) {
1049 cl->do_generation(_gens[i]);
1050 }
1051 }
1052 }
1053
1054 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1055 for (int i = 0; i < _n_gens; i++) {
1056 _gens[i]->space_iterate(cl, true);
1057 }
1058 }
1059
1060 bool GenCollectedHeap::is_maximal_no_gc() const {
1061 for (int i = 0; i < _n_gens; i++) {
1062 if (!_gens[i]->is_maximal_no_gc()) {
1063 return false;
1064 }
1065 }
1066 return true;
1067 }
1068
1069 void GenCollectedHeap::save_marks() {
1070 for (int i = 0; i < _n_gens; i++) {
1071 _gens[i]->save_marks();
1072 }
1073 }
1074
1075 GenCollectedHeap* GenCollectedHeap::heap() {
1076 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1077 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1078 return _gch;
1079 }
1080
1081
1082 void GenCollectedHeap::prepare_for_compaction() {
1083 guarantee(_n_gens = 2, "Wrong number of generations");
1084 Generation* old_gen = _gens[1];
1085 // Start by compacting into same gen.
1086 CompactPoint cp(old_gen);
1087 old_gen->prepare_for_compaction(&cp);
1088 Generation* young_gen = _gens[0];
1089 young_gen->prepare_for_compaction(&cp);
1090 }
1091
1092 GCStats* GenCollectedHeap::gc_stats(int level) const {
1093 return _gens[level]->gc_stats();
1094 }
1095
1096 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1097 for (int i = _n_gens-1; i >= 0; i--) {
1098 Generation* g = _gens[i];
1099 if (!silent) {
1100 gclog_or_tty->print("%s", g->name());
1101 gclog_or_tty->print(" ");
1102 }
1103 g->verify();
1104 }
1105 if (!silent) {
1106 gclog_or_tty->print("remset ");
1107 }
1108 rem_set()->verify();
1109 }
1110
1111 void GenCollectedHeap::print_on(outputStream* st) const {
1112 for (int i = 0; i < _n_gens; i++) {
1113 _gens[i]->print_on(st);
1114 }
1115 MetaspaceAux::print_on(st);
1116 }
1117
1118 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1119 if (workers() != NULL) {
1120 workers()->threads_do(tc);
1121 }
1122 #if INCLUDE_ALL_GCS
1123 if (UseConcMarkSweepGC) {
1124 ConcurrentMarkSweepThread::threads_do(tc);
1125 }
1126 #endif // INCLUDE_ALL_GCS
1127 }
1128
1129 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1130 #if INCLUDE_ALL_GCS
1131 if (UseParNewGC) {
1132 workers()->print_worker_threads_on(st);
1133 }
1134 if (UseConcMarkSweepGC) {
|
113 ReservedSpace heap_rs;
114
115 size_t heap_alignment = collector_policy()->heap_alignment();
116
117 heap_address = allocate(heap_alignment, &total_reserved,
118 &n_covered_regions, &heap_rs);
119
120 if (!heap_rs.is_reserved()) {
121 vm_shutdown_during_initialization(
122 "Could not reserve enough space for object heap");
123 return JNI_ENOMEM;
124 }
125
126 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
127
128 _rem_set = collector_policy()->create_rem_set(reserved_region(), n_covered_regions);
129 set_barrier_set(rem_set()->bs());
130
131 _gch = this;
132
133 ReservedSpace young_rs = heap_rs.first_part(_gen_specs[0]->max_size(), false, false);
134 _young_gen = _gen_specs[0]->init(young_rs, 0, rem_set());
135 heap_rs = heap_rs.last_part(_gen_specs[0]->max_size());
136
137 ReservedSpace old_rs = heap_rs.first_part(_gen_specs[1]->max_size(), false, false);
138 _old_gen = _gen_specs[1]->init(old_rs, 1, rem_set());
139 heap_rs = heap_rs.last_part(_gen_specs[1]->max_size());
140 clear_incremental_collection_failed();
141
142 #if INCLUDE_ALL_GCS
143 // If we are running CMS, create the collector responsible
144 // for collecting the CMS generations.
145 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
146 bool success = create_cms_collector();
147 if (!success) return JNI_ENOMEM;
148 }
149 #endif // INCLUDE_ALL_GCS
150
151 return JNI_OK;
152 }
153
154 char* GenCollectedHeap::allocate(size_t alignment,
155 size_t* _total_reserved,
156 int* _n_covered_regions,
157 ReservedSpace* heap_rs){
158 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
159 "the maximum representable size";
160
161 // Now figure out the total size.
162 size_t total_reserved = 0;
163 int n_covered_regions = 0;
164 const size_t pageSize = UseLargePages ?
165 os::large_page_size() : os::vm_page_size();
166
167 assert(alignment % pageSize == 0, "Must be");
168
169 for (int i = 0; i < _n_gens; i++) {
170 total_reserved += _gen_specs[i]->max_size();
171 if (total_reserved < _gen_specs[i]->max_size()) {
172 vm_exit_during_initialization(overflow_msg);
173 }
174 n_covered_regions += _gen_specs[i]->n_covered_regions();
175 }
176 assert(total_reserved % alignment == 0,
177 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
178 SIZE_FORMAT, total_reserved, alignment));
179
180 // Needed until the cardtable is fixed to have the right number
181 // of covered regions.
182 n_covered_regions += 2;
183
184 *_total_reserved = total_reserved;
185 *_n_covered_regions = n_covered_regions;
186
187 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
188 return heap_rs->base();
189 }
190
191 void GenCollectedHeap::post_initialize() {
192 SharedHeap::post_initialize();
193 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
194 guarantee(policy->is_generation_policy(), "Illegal policy type");
195 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
196 assert(def_new_gen->kind() == Generation::DefNew ||
197 def_new_gen->kind() == Generation::ParNew,
198 "Wrong generation kind");
199
200 Generation* old_gen = get_gen(1);
201 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
202 old_gen->kind() == Generation::MarkSweepCompact,
203 "Wrong generation kind");
204
205 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
206 old_gen->capacity(),
207 def_new_gen->from()->capacity());
208 policy->initialize_gc_policy_counters();
209 }
210
211 void GenCollectedHeap::ref_processing_init() {
212 SharedHeap::ref_processing_init();
213 _young_gen->ref_processor_init();
214 _old_gen->ref_processor_init();
215 }
216
217 size_t GenCollectedHeap::capacity() const {
218 return _young_gen->capacity() + _old_gen->capacity();
219 }
220
221 size_t GenCollectedHeap::used() const {
222 return _young_gen->used() + _old_gen->used();
223 }
224
225 // Save the "used_region" for generations level and lower.
226 void GenCollectedHeap::save_used_regions(int level) {
227 assert(level < _n_gens, "Illegal level parameter");
228 if (level == 1) {
229 _old_gen->save_used_region();
230 }
231 _young_gen->save_used_region();
232 }
233
234 size_t GenCollectedHeap::max_capacity() const {
235 return _young_gen->max_capacity() + _old_gen->max_capacity();
236 }
237
238 // Update the _full_collections_completed counter
239 // at the end of a stop-world full GC.
240 unsigned int GenCollectedHeap::update_full_collections_completed() {
241 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
242 assert(_full_collections_completed <= _total_full_collections,
243 "Can't complete more collections than were started");
244 _full_collections_completed = _total_full_collections;
245 ml.notify_all();
246 return _full_collections_completed;
247 }
248
249 // Update the _full_collections_completed counter, as appropriate,
250 // at the end of a concurrent GC cycle. Note the conditional update
251 // below to allow this method to be called by a concurrent collector
252 // without synchronizing in any manner with the VM thread (which
253 // may already have initiated a STW full collection "concurrently").
254 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
255 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
279 // higher than we are prepared to pay for such rudimentary debugging
280 // support.
281 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
282 size_t size) {
283 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
284 // We are asked to check a size in HeapWords,
285 // but the memory is mangled in juint words.
286 juint* start = (juint*) (addr + skip_header_HeapWords());
287 juint* end = (juint*) (addr + size);
288 for (juint* slot = start; slot < end; slot += 1) {
289 assert(*slot == badHeapWordVal,
290 "Found non badHeapWordValue in pre-allocation check");
291 }
292 }
293 }
294 #endif
295
296 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
297 bool is_tlab,
298 bool first_only) {
299 HeapWord* res = NULL;
300
301 if (_young_gen->should_allocate(size, is_tlab)) {
302 res = _young_gen->allocate(size, is_tlab);
303 if (res != NULL || first_only) {
304 return res;
305 }
306 }
307
308 if (_old_gen->should_allocate(size, is_tlab)) {
309 res = _old_gen->allocate(size, is_tlab);
310 }
311
312 return res;
313 }
314
315 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
316 bool* gc_overhead_limit_was_exceeded) {
317 return collector_policy()->mem_allocate_work(size,
318 false /* is_tlab */,
319 gc_overhead_limit_was_exceeded);
320 }
321
322 bool GenCollectedHeap::must_clear_all_soft_refs() {
323 return _gc_cause == GCCause::_last_ditch_collection;
324 }
325
326 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
327 return UseConcMarkSweepGC &&
328 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
329 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
330 }
331
332 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
333 bool is_tlab, bool run_verification, bool clear_soft_refs) {
334 // Timer for individual generations. Last argument is false: no CR
335 // FIXME: We should try to start the timing earlier to cover more of the GC pause
336 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
337 // so we can assume here that the next GC id is what we want.
338 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek());
339 TraceCollectorStats tcs(gen->counters());
340 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
341
342 size_t prev_used = gen->used();
343 gen->stat_record()->invocations++;
344 gen->stat_record()->accumulated_time.start();
345
346 // Must be done anew before each collection because
347 // a previous collection will do mangling and will
348 // change top of some spaces.
349 record_gen_tops_before_GC();
350
351 if (PrintGC && Verbose) {
352 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
353 gen->level(),
354 gen->stat_record()->invocations,
355 size * HeapWordSize);
356 }
357
358 if (run_verification && VerifyBeforeGC) {
359 HandleMark hm; // Discard invalid handles created during verification
360 Universe::verify(" VerifyBeforeGC:");
361 }
362 COMPILER2_PRESENT(DerivedPointerTable::clear());
363
364 // Do collection work
365 {
366 // Note on ref discovery: For what appear to be historical reasons,
367 // GCH enables and disabled (by enqueing) refs discovery.
368 // In the future this should be moved into the generation's
369 // collect method so that ref discovery and enqueueing concerns
370 // are local to a generation. The collect method could return
371 // an appropriate indication in the case that notification on
372 // the ref lock was needed. This will make the treatment of
373 // weak refs more uniform (and indeed remove such concerns
374 // from GCH). XXX
375
376 HandleMark hm; // Discard invalid handles created during gc
377 save_marks(); // save marks for all gens
378 // We want to discover references, but not process them yet.
379 // This mode is disabled in process_discovered_references if the
380 // generation does some collection work, or in
381 // enqueue_discovered_references if the generation returns
382 // without doing any work.
383 ReferenceProcessor* rp = gen->ref_processor();
384 // If the discovery of ("weak") refs in this generation is
385 // atomic wrt other collectors in this configuration, we
386 // are guaranteed to have empty discovered ref lists.
387 if (rp->discovery_is_atomic()) {
388 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
389 rp->setup_policy(clear_soft_refs);
390 } else {
391 // collect() below will enable discovery as appropriate
392 }
393 gen->collect(full, clear_soft_refs, size, is_tlab);
394 if (!rp->enqueuing_is_done()) {
395 rp->enqueue_discovered_references();
396 } else {
397 rp->set_enqueuing_is_done(false);
398 }
399 rp->verify_no_references_recorded();
400 }
401
402 // Determine if allocation request was met.
403 if (size > 0) {
404 if (!is_tlab || gen->supports_tlab_allocation()) {
405 if (size * HeapWordSize <= gen->unsafe_max_alloc_nogc()) {
406 size = 0;
407 }
408 }
409 }
410
411 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
412
413 gen->stat_record()->accumulated_time.stop();
414
415 update_gc_stats(gen->level(), full);
416
417 if (run_verification && VerifyAfterGC) {
418 HandleMark hm; // Discard invalid handles created during verification
419 Universe::verify(" VerifyAfterGC:");
420 }
421
422 if (PrintGCDetails) {
423 gclog_or_tty->print(":");
424 gen->print_heap_change(prev_used);
425 }
426 }
427
428 void GenCollectedHeap::do_collection(bool full,
429 bool clear_all_soft_refs,
430 size_t size,
431 bool is_tlab,
432 int max_level) {
433 ResourceMark rm;
434 DEBUG_ONLY(Thread* my_thread = Thread::current();)
435
436 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
437 assert(my_thread->is_VM_thread() ||
438 my_thread->is_ConcurrentGC_thread(),
439 "incorrect thread type capability");
440 assert(Heap_lock->is_locked(),
441 "the requesting thread should have the Heap_lock");
442 guarantee(!is_gc_active(), "collection is not reentrant");
443 assert(max_level < n_gens(), "sanity check");
444
445 if (GC_locker::check_active_before_gc()) {
446 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
447 }
448
449 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
450 collector_policy()->should_clear_all_soft_refs();
451
452 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
453
454 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
455
456 print_heap_before_gc();
457
458 {
459 FlagSetting fl(_is_gc_active, true);
460
461 bool complete = full && (max_level == (n_gens()-1));
462 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
463 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
464 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
465 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
466 // so we can assume here that the next GC id is what we want.
467 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
468
469 gc_prologue(complete);
470 increment_total_collections(complete);
471
472 size_t gch_prev_used = used();
473 bool must_restore_marks_for_biased_locking = false;
474 bool run_verification = total_collections() >= VerifyGCStartAt;
475
476 if (_young_gen->performs_in_place_marking() ||
477 _old_gen->performs_in_place_marking()) {
478 // We want to avoid doing this for
479 // scavenge-only collections where it's unnecessary.
480 must_restore_marks_for_biased_locking = true;
481 BiasedLocking::preserve_marks();
482 }
483
484 bool prepared_for_verification = false;
485 int max_level_collected = 0;
486 if (!(full && _old_gen->full_collects_younger_generations()) &&
487 _young_gen->should_collect(full, size, is_tlab)) {
488 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
489 prepare_for_verify();
490 prepared_for_verification = true;
491 }
492 collect_generation(_young_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 0, do_clear_all_soft_refs);
493 }
494 if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) {
495 if (!complete) {
496 // The full_collections increment was missed above.
497 increment_total_full_collections();
498 }
499 pre_full_gc_dump(NULL); // do any pre full gc dumps
500 if (run_verification && VerifyGCLevel <= 1 && VerifyBeforeGC) {
501 if (!prepared_for_verification) {
502 prepare_for_verify();
503 }
504 }
505 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs);
506 max_level_collected = 1;
507 }
508
509 // Update "complete" boolean wrt what actually transpired --
510 // for instance, a promotion failure could have led to
511 // a whole heap collection.
512 complete = complete || (max_level_collected == n_gens() - 1);
513
514 if (complete) { // We did a "major" collection
515 // FIXME: See comment at pre_full_gc_dump call
516 post_full_gc_dump(NULL); // do any post full gc dumps
517 }
518
519 if (PrintGCDetails) {
520 print_heap_change(gch_prev_used);
521
522 // Print metaspace info for full GC with PrintGCDetails flag.
523 if (complete) {
524 MetaspaceAux::print_metaspace_change(metadata_prev_used);
525 }
526 }
527
528 // Adjust generation sizes.
529 if (max_level_collected == 1) {
530 _old_gen->compute_new_size();
531 }
532 _young_gen->compute_new_size();
533
534 if (complete) {
535 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
536 ClassLoaderDataGraph::purge();
537 MetaspaceAux::verify_metrics();
538 // Resize the metaspace capacity after full collections
539 MetaspaceGC::compute_new_size();
540 update_full_collections_completed();
541 }
542
543 // Track memory usage and detect low memory after GC finishes
544 MemoryService::track_memory_usage();
545
546 gc_epilogue(complete);
547
548 if (must_restore_marks_for_biased_locking) {
549 BiasedLocking::restore_marks();
550 }
551 }
552
569 void GenCollectedHeap::
570 gen_process_roots(int level,
571 bool younger_gens_as_roots,
572 bool activate_scope,
573 SharedHeap::ScanningOption so,
574 OopsInGenClosure* not_older_gens,
575 OopsInGenClosure* weak_roots,
576 OopsInGenClosure* older_gens,
577 CLDClosure* cld_closure,
578 CLDClosure* weak_cld_closure,
579 CodeBlobClosure* code_closure) {
580
581 // General roots.
582 SharedHeap::process_roots(activate_scope, so,
583 not_older_gens, weak_roots,
584 cld_closure, weak_cld_closure,
585 code_closure);
586
587 if (younger_gens_as_roots) {
588 if (!_gen_process_roots_tasks->is_task_claimed(GCH_PS_younger_gens)) {
589 if (level == 1) {
590 not_older_gens->set_generation(_young_gen);
591 _young_gen->oop_iterate(not_older_gens);
592 }
593 not_older_gens->reset_generation();
594 }
595 }
596 // When collection is parallel, all threads get to cooperate to do
597 // older-gen scanning.
598 if (level == 0) {
599 older_gens->set_generation(_old_gen);
600 rem_set()->younger_refs_iterate(_old_gen, older_gens);
601 older_gens->reset_generation();
602 }
603
604 _gen_process_roots_tasks->all_tasks_completed();
605 }
606
607 void GenCollectedHeap::
608 gen_process_roots(int level,
609 bool younger_gens_as_roots,
610 bool activate_scope,
611 SharedHeap::ScanningOption so,
612 bool only_strong_roots,
613 OopsInGenClosure* not_older_gens,
614 OopsInGenClosure* older_gens,
615 CLDClosure* cld_closure) {
616
617 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
618
619 bool is_moving_collection = false;
620 if (level == 0 || is_adjust_phase) {
621 // young collections are always moving
622 is_moving_collection = true;
623 }
624
625 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
626 CodeBlobClosure* code_closure = &mark_code_closure;
627
628 gen_process_roots(level,
629 younger_gens_as_roots,
630 activate_scope, so,
631 not_older_gens, only_strong_roots ? NULL : not_older_gens,
632 older_gens,
633 cld_closure, only_strong_roots ? NULL : cld_closure,
634 code_closure);
635
636 }
637
638 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
639 SharedHeap::process_weak_roots(root_closure);
640 // "Local" "weak" refs
641 _young_gen->ref_processor()->weak_oops_do(root_closure);
642 _old_gen->ref_processor()->weak_oops_do(root_closure);
643 }
644
645 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
646 void GenCollectedHeap:: \
647 oop_since_save_marks_iterate(int level, \
648 OopClosureType* cur, \
649 OopClosureType* older) { \
650 if (level == 0) { \
651 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
652 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
653 } else { \
654 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
655 } \
656 }
657
658 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
659
660 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
661
662 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
663 if (level == 0) {
664 if (!_young_gen->no_allocs_since_save_marks()) return false;
665 }
666 if (!_old_gen->no_allocs_since_save_marks()) return false;
667 return true;
668 }
669
670 bool GenCollectedHeap::supports_inline_contig_alloc() const {
671 return _young_gen->supports_inline_contig_alloc();
672 }
673
674 HeapWord** GenCollectedHeap::top_addr() const {
675 return _young_gen->top_addr();
676 }
677
678 HeapWord** GenCollectedHeap::end_addr() const {
679 return _young_gen->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(_old_gen->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*)_old_gen,
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) < _old_gen->reserved().start();
815 assert(result == _young_gen->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 if (_young_gen->is_in(p) || _old_gen->is_in(p)) {
836 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 < _young_gen->reserved().end() && p != NULL;
849 }
850 #endif
851
852 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
853 _young_gen->oop_iterate(cl);
854 _old_gen->oop_iterate(cl);
855 }
856
857 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
858 _young_gen->object_iterate(cl);
859 _old_gen->object_iterate(cl);
860 }
861
862 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
863 _young_gen->safe_object_iterate(cl);
864 _old_gen->safe_object_iterate(cl);
865 }
866
867 Space* GenCollectedHeap::space_containing(const void* addr) const {
868 Space* res = _young_gen->space_containing(addr);
869 if (res != NULL) {
870 return res;
871 }
872 res = _old_gen->space_containing(addr);
873 assert(res != NULL, "Could not find containing space");
874 return res;
875 }
876
877 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
878 assert(is_in_reserved(addr), "block_start of address outside of heap");
879 if (_young_gen->is_in_reserved(addr)) {
880 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
881 return _young_gen->block_start(addr);
882 }
883
884 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
885 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
886 return _old_gen->block_start(addr);
887 }
888
889 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
890 assert(is_in_reserved(addr), "block_size of address outside of heap");
891 if (_young_gen->is_in_reserved(addr)) {
892 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
893 return _young_gen->block_size(addr);
894 }
895
896 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
897 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
898 return _old_gen->block_size(addr);
899 }
900
901 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
902 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
903 assert(block_start(addr) == addr, "addr must be a block start");
904 if (_young_gen->is_in_reserved(addr)) {
905 return _young_gen->block_is_obj(addr);
906 }
907
908 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
909 return _old_gen->block_is_obj(addr);
910 }
911
912 bool GenCollectedHeap::supports_tlab_allocation() const {
913 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
914 return _young_gen->supports_tlab_allocation();
915 }
916
917 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
918 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
919 if (_young_gen->supports_tlab_allocation()) {
920 return _young_gen->tlab_capacity();
921 }
922 return 0;
923 }
924
925 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
926 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
927 if (_young_gen->supports_tlab_allocation()) {
928 return _young_gen->tlab_used();
929 }
930 return 0;
931 }
932
933 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
934 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
935 if (_young_gen->supports_tlab_allocation()) {
936 return _young_gen->unsafe_max_tlab_alloc();
937 }
938 return 0;
939 }
940
941 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
942 bool gc_overhead_limit_was_exceeded;
943 return collector_policy()->mem_allocate_work(size /* size */,
944 true /* is_tlab */,
945 &gc_overhead_limit_was_exceeded);
946 }
947
948 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
949 // from the list headed by "*prev_ptr".
950 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
951 bool first = true;
952 size_t min_size = 0; // "first" makes this conceptually infinite.
953 ScratchBlock **smallest_ptr, *smallest;
954 ScratchBlock *cur = *prev_ptr;
955 while (cur) {
956 assert(*prev_ptr == cur, "just checking");
957 if (first || cur->num_words < min_size) {
958 smallest_ptr = prev_ptr;
967 *smallest_ptr = smallest->next;
968 return smallest;
969 }
970
971 // Sort the scratch block list headed by res into decreasing size order,
972 // and set "res" to the result.
973 static void sort_scratch_list(ScratchBlock*& list) {
974 ScratchBlock* sorted = NULL;
975 ScratchBlock* unsorted = list;
976 while (unsorted) {
977 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
978 smallest->next = sorted;
979 sorted = smallest;
980 }
981 list = sorted;
982 }
983
984 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
985 size_t max_alloc_words) {
986 ScratchBlock* res = NULL;
987 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
988 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
989 sort_scratch_list(res);
990 return res;
991 }
992
993 void GenCollectedHeap::release_scratch() {
994 _young_gen->reset_scratch();
995 _old_gen->reset_scratch();
996 }
997
998 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
999 void do_generation(Generation* gen) {
1000 gen->prepare_for_verify();
1001 }
1002 };
1003
1004 void GenCollectedHeap::prepare_for_verify() {
1005 ensure_parsability(false); // no need to retire TLABs
1006 GenPrepareForVerifyClosure blk;
1007 generation_iterate(&blk, false);
1008 }
1009
1010 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1011 bool old_to_young) {
1012 if (old_to_young) {
1013 cl->do_generation(_old_gen);
1014 cl->do_generation(_young_gen);
1015 } else {
1016 cl->do_generation(_young_gen);
1017 cl->do_generation(_old_gen);
1018 }
1019 }
1020
1021 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1022 _young_gen->space_iterate(cl, true);
1023 _old_gen->space_iterate(cl, true);
1024 }
1025
1026 bool GenCollectedHeap::is_maximal_no_gc() const {
1027 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1028 }
1029
1030 void GenCollectedHeap::save_marks() {
1031 _young_gen->save_marks();
1032 _old_gen->save_marks();
1033 }
1034
1035 GenCollectedHeap* GenCollectedHeap::heap() {
1036 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1037 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1038 return _gch;
1039 }
1040
1041
1042 void GenCollectedHeap::prepare_for_compaction() {
1043 guarantee(_n_gens = 2, "Wrong number of generations");
1044 Generation* old_gen = _old_gen;
1045 // Start by compacting into same gen.
1046 CompactPoint cp(old_gen);
1047 old_gen->prepare_for_compaction(&cp);
1048 Generation* young_gen = _young_gen;
1049 young_gen->prepare_for_compaction(&cp);
1050 }
1051
1052 GCStats* GenCollectedHeap::gc_stats(int level) const {
1053 if (level == 0) {
1054 return _young_gen->gc_stats();
1055 } else {
1056 return _old_gen->gc_stats();
1057 }
1058 }
1059
1060 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1061 if (!silent) {
1062 gclog_or_tty->print("%s", _old_gen->name());
1063 gclog_or_tty->print(" ");
1064 }
1065 _old_gen->verify();
1066
1067 if (!silent) {
1068 gclog_or_tty->print("%s", _young_gen->name());
1069 gclog_or_tty->print(" ");
1070 }
1071 _young_gen->verify();
1072
1073 if (!silent) {
1074 gclog_or_tty->print("remset ");
1075 }
1076 rem_set()->verify();
1077 }
1078
1079 void GenCollectedHeap::print_on(outputStream* st) const {
1080 _young_gen->print_on(st);
1081 _old_gen->print_on(st);
1082 MetaspaceAux::print_on(st);
1083 }
1084
1085 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1086 if (workers() != NULL) {
1087 workers()->threads_do(tc);
1088 }
1089 #if INCLUDE_ALL_GCS
1090 if (UseConcMarkSweepGC) {
1091 ConcurrentMarkSweepThread::threads_do(tc);
1092 }
1093 #endif // INCLUDE_ALL_GCS
1094 }
1095
1096 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1097 #if INCLUDE_ALL_GCS
1098 if (UseParNewGC) {
1099 workers()->print_worker_threads_on(st);
1100 }
1101 if (UseConcMarkSweepGC) {
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