1/*
2 * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "aot/aotLoader.hpp"
27#include "classfile/classLoaderDataGraph.hpp"
28#include "classfile/symbolTable.hpp"
29#include "classfile/stringTable.hpp"
30#include "classfile/systemDictionary.hpp"
31#include "classfile/vmSymbols.hpp"
32#include "code/codeCache.hpp"
33#include "code/icBuffer.hpp"
34#include "gc/serial/defNewGeneration.hpp"
35#include "gc/shared/adaptiveSizePolicy.hpp"
36#include "gc/shared/cardTableBarrierSet.hpp"
37#include "gc/shared/cardTableRS.hpp"
38#include "gc/shared/collectedHeap.inline.hpp"
39#include "gc/shared/collectorCounters.hpp"
40#include "gc/shared/gcId.hpp"
41#include "gc/shared/gcLocker.hpp"
42#include "gc/shared/gcPolicyCounters.hpp"
43#include "gc/shared/gcTrace.hpp"
44#include "gc/shared/gcTraceTime.inline.hpp"
45#include "gc/shared/genArguments.hpp"
46#include "gc/shared/gcVMOperations.hpp"
47#include "gc/shared/genCollectedHeap.hpp"
48#include "gc/shared/genOopClosures.inline.hpp"
49#include "gc/shared/generationSpec.hpp"
50#include "gc/shared/oopStorageParState.inline.hpp"
51#include "gc/shared/scavengableNMethods.hpp"
52#include "gc/shared/space.hpp"
53#include "gc/shared/strongRootsScope.hpp"
54#include "gc/shared/weakProcessor.hpp"
55#include "gc/shared/workgroup.hpp"
56#include "memory/filemap.hpp"
57#include "memory/metaspaceCounters.hpp"
58#include "memory/resourceArea.hpp"
59#include "memory/universe.hpp"
60#include "oops/oop.inline.hpp"
61#include "runtime/biasedLocking.hpp"
62#include "runtime/flags/flagSetting.hpp"
63#include "runtime/handles.hpp"
64#include "runtime/handles.inline.hpp"
65#include "runtime/java.hpp"
66#include "runtime/vmThread.hpp"
67#include "services/management.hpp"
68#include "services/memoryService.hpp"
69#include "utilities/debug.hpp"
70#include "utilities/formatBuffer.hpp"
71#include "utilities/macros.hpp"
72#include "utilities/stack.inline.hpp"
73#include "utilities/vmError.hpp"
74#if INCLUDE_JVMCI
75#include "jvmci/jvmci.hpp"
76#endif
77
78GenCollectedHeap::GenCollectedHeap(Generation::Name young,
79 Generation::Name old,
80 const char* policy_counters_name) :
81 CollectedHeap(),
82 _young_gen_spec(new GenerationSpec(young,
83 NewSize,
84 MaxNewSize,
85 GenAlignment)),
86 _old_gen_spec(new GenerationSpec(old,
87 OldSize,
88 MaxOldSize,
89 GenAlignment)),
90 _rem_set(NULL),
91 _soft_ref_gen_policy(),
92 _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)),
93 _full_collections_completed(0),
94 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)) {
95}
96
97jint GenCollectedHeap::initialize() {
98 // While there are no constraints in the GC code that HeapWordSize
99 // be any particular value, there are multiple other areas in the
100 // system which believe this to be true (e.g. oop->object_size in some
101 // cases incorrectly returns the size in wordSize units rather than
102 // HeapWordSize).
103 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
104
105 // Allocate space for the heap.
106
107 char* heap_address;
108 ReservedSpace heap_rs;
109
110 heap_address = allocate(HeapAlignment, &heap_rs);
111
112 if (!heap_rs.is_reserved()) {
113 vm_shutdown_during_initialization(
114 "Could not reserve enough space for object heap");
115 return JNI_ENOMEM;
116 }
117
118 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
119
120 _rem_set = create_rem_set(reserved_region());
121 _rem_set->initialize();
122 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set);
123 bs->initialize();
124 BarrierSet::set_barrier_set(bs);
125
126 ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size(), false, false);
127 _young_gen = _young_gen_spec->init(young_rs, rem_set());
128 heap_rs = heap_rs.last_part(_young_gen_spec->max_size());
129
130 ReservedSpace old_rs = heap_rs.first_part(_old_gen_spec->max_size(), false, false);
131 _old_gen = _old_gen_spec->init(old_rs, rem_set());
132 clear_incremental_collection_failed();
133
134 return JNI_OK;
135}
136
137CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) {
138 return new CardTableRS(reserved_region, false /* scan_concurrently */);
139}
140
141void GenCollectedHeap::initialize_size_policy(size_t init_eden_size,
142 size_t init_promo_size,
143 size_t init_survivor_size) {
144 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
145 _size_policy = new AdaptiveSizePolicy(init_eden_size,
146 init_promo_size,
147 init_survivor_size,
148 max_gc_pause_sec,
149 GCTimeRatio);
150}
151
152char* GenCollectedHeap::allocate(size_t alignment,
153 ReservedSpace* heap_rs){
154 // Now figure out the total size.
155 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
156 assert(alignment % pageSize == 0, "Must be");
157
158 // Check for overflow.
159 size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size();
160 if (total_reserved < _young_gen_spec->max_size()) {
161 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
162 "the maximum representable size");
163 }
164 assert(total_reserved % alignment == 0,
165 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
166 SIZE_FORMAT, total_reserved, alignment);
167
168 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
169
170 os::trace_page_sizes("Heap",
171 MinHeapSize,
172 total_reserved,
173 alignment,
174 heap_rs->base(),
175 heap_rs->size());
176
177 return heap_rs->base();
178}
179
180class GenIsScavengable : public BoolObjectClosure {
181public:
182 bool do_object_b(oop obj) {
183 return GenCollectedHeap::heap()->is_in_young(obj);
184 }
185};
186
187static GenIsScavengable _is_scavengable;
188
189void GenCollectedHeap::post_initialize() {
190 CollectedHeap::post_initialize();
191 ref_processing_init();
192
193 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
194
195 initialize_size_policy(def_new_gen->eden()->capacity(),
196 _old_gen->capacity(),
197 def_new_gen->from()->capacity());
198
199 MarkSweep::initialize();
200
201 ScavengableNMethods::initialize(&_is_scavengable);
202}
203
204void GenCollectedHeap::ref_processing_init() {
205 _young_gen->ref_processor_init();
206 _old_gen->ref_processor_init();
207}
208
209GenerationSpec* GenCollectedHeap::young_gen_spec() const {
210 return _young_gen_spec;
211}
212
213GenerationSpec* GenCollectedHeap::old_gen_spec() const {
214 return _old_gen_spec;
215}
216
217size_t GenCollectedHeap::capacity() const {
218 return _young_gen->capacity() + _old_gen->capacity();
219}
220
221size_t GenCollectedHeap::used() const {
222 return _young_gen->used() + _old_gen->used();
223}
224
225void GenCollectedHeap::save_used_regions() {
226 _old_gen->save_used_region();
227 _young_gen->save_used_region();
228}
229
230size_t GenCollectedHeap::max_capacity() const {
231 return _young_gen->max_capacity() + _old_gen->max_capacity();
232}
233
234// Update the _full_collections_completed counter
235// at the end of a stop-world full GC.
236unsigned int GenCollectedHeap::update_full_collections_completed() {
237 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
238 assert(_full_collections_completed <= _total_full_collections,
239 "Can't complete more collections than were started");
240 _full_collections_completed = _total_full_collections;
241 ml.notify_all();
242 return _full_collections_completed;
243}
244
245// Update the _full_collections_completed counter, as appropriate,
246// at the end of a concurrent GC cycle. Note the conditional update
247// below to allow this method to be called by a concurrent collector
248// without synchronizing in any manner with the VM thread (which
249// may already have initiated a STW full collection "concurrently").
250unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
251 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
252 assert((_full_collections_completed <= _total_full_collections) &&
253 (count <= _total_full_collections),
254 "Can't complete more collections than were started");
255 if (count > _full_collections_completed) {
256 _full_collections_completed = count;
257 ml.notify_all();
258 }
259 return _full_collections_completed;
260}
261
262// Return true if any of the following is true:
263// . the allocation won't fit into the current young gen heap
264// . gc locker is occupied (jni critical section)
265// . heap memory is tight -- the most recent previous collection
266// was a full collection because a partial collection (would
267// have) failed and is likely to fail again
268bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const {
269 size_t young_capacity = _young_gen->capacity_before_gc();
270 return (word_size > heap_word_size(young_capacity))
271 || GCLocker::is_active_and_needs_gc()
272 || incremental_collection_failed();
273}
274
275HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) {
276 HeapWord* result = NULL;
277 if (_old_gen->should_allocate(size, is_tlab)) {
278 result = _old_gen->expand_and_allocate(size, is_tlab);
279 }
280 if (result == NULL) {
281 if (_young_gen->should_allocate(size, is_tlab)) {
282 result = _young_gen->expand_and_allocate(size, is_tlab);
283 }
284 }
285 assert(result == NULL || is_in_reserved(result), "result not in heap");
286 return result;
287}
288
289HeapWord* GenCollectedHeap::mem_allocate_work(size_t size,
290 bool is_tlab,
291 bool* gc_overhead_limit_was_exceeded) {
292 // In general gc_overhead_limit_was_exceeded should be false so
293 // set it so here and reset it to true only if the gc time
294 // limit is being exceeded as checked below.
295 *gc_overhead_limit_was_exceeded = false;
296
297 HeapWord* result = NULL;
298
299 // Loop until the allocation is satisfied, or unsatisfied after GC.
300 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
301 HandleMark hm; // Discard any handles allocated in each iteration.
302
303 // First allocation attempt is lock-free.
304 Generation *young = _young_gen;
305 assert(young->supports_inline_contig_alloc(),
306 "Otherwise, must do alloc within heap lock");
307 if (young->should_allocate(size, is_tlab)) {
308 result = young->par_allocate(size, is_tlab);
309 if (result != NULL) {
310 assert(is_in_reserved(result), "result not in heap");
311 return result;
312 }
313 }
314 uint gc_count_before; // Read inside the Heap_lock locked region.
315 {
316 MutexLocker ml(Heap_lock);
317 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation");
318 // Note that only large objects get a shot at being
319 // allocated in later generations.
320 bool first_only = !should_try_older_generation_allocation(size);
321
322 result = attempt_allocation(size, is_tlab, first_only);
323 if (result != NULL) {
324 assert(is_in_reserved(result), "result not in heap");
325 return result;
326 }
327
328 if (GCLocker::is_active_and_needs_gc()) {
329 if (is_tlab) {
330 return NULL; // Caller will retry allocating individual object.
331 }
332 if (!is_maximal_no_gc()) {
333 // Try and expand heap to satisfy request.
334 result = expand_heap_and_allocate(size, is_tlab);
335 // Result could be null if we are out of space.
336 if (result != NULL) {
337 return result;
338 }
339 }
340
341 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
342 return NULL; // We didn't get to do a GC and we didn't get any memory.
343 }
344
345 // If this thread is not in a jni critical section, we stall
346 // the requestor until the critical section has cleared and
347 // GC allowed. When the critical section clears, a GC is
348 // initiated by the last thread exiting the critical section; so
349 // we retry the allocation sequence from the beginning of the loop,
350 // rather than causing more, now probably unnecessary, GC attempts.
351 JavaThread* jthr = JavaThread::current();
352 if (!jthr->in_critical()) {
353 MutexUnlocker mul(Heap_lock);
354 // Wait for JNI critical section to be exited
355 GCLocker::stall_until_clear();
356 gclocker_stalled_count += 1;
357 continue;
358 } else {
359 if (CheckJNICalls) {
360 fatal("Possible deadlock due to allocating while"
361 " in jni critical section");
362 }
363 return NULL;
364 }
365 }
366
367 // Read the gc count while the heap lock is held.
368 gc_count_before = total_collections();
369 }
370
371 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
372 VMThread::execute(&op);
373 if (op.prologue_succeeded()) {
374 result = op.result();
375 if (op.gc_locked()) {
376 assert(result == NULL, "must be NULL if gc_locked() is true");
377 continue; // Retry and/or stall as necessary.
378 }
379
380 // Allocation has failed and a collection
381 // has been done. If the gc time limit was exceeded the
382 // this time, return NULL so that an out-of-memory
383 // will be thrown. Clear gc_overhead_limit_exceeded
384 // so that the overhead exceeded does not persist.
385
386 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
387 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear();
388
389 if (limit_exceeded && softrefs_clear) {
390 *gc_overhead_limit_was_exceeded = true;
391 size_policy()->set_gc_overhead_limit_exceeded(false);
392 if (op.result() != NULL) {
393 CollectedHeap::fill_with_object(op.result(), size);
394 }
395 return NULL;
396 }
397 assert(result == NULL || is_in_reserved(result),
398 "result not in heap");
399 return result;
400 }
401
402 // Give a warning if we seem to be looping forever.
403 if ((QueuedAllocationWarningCount > 0) &&
404 (try_count % QueuedAllocationWarningCount == 0)) {
405 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times,"
406 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : "");
407 }
408 }
409}
410
411#ifndef PRODUCT
412// Override of memory state checking method in CollectedHeap:
413// Some collectors (CMS for example) can't have badHeapWordVal written
414// in the first two words of an object. (For instance , in the case of
415// CMS these words hold state used to synchronize between certain
416// (concurrent) GC steps and direct allocating mutators.)
417// The skip_header_HeapWords() method below, allows us to skip
418// over the requisite number of HeapWord's. Note that (for
419// generational collectors) this means that those many words are
420// skipped in each object, irrespective of the generation in which
421// that object lives. The resultant loss of precision seems to be
422// harmless and the pain of avoiding that imprecision appears somewhat
423// higher than we are prepared to pay for such rudimentary debugging
424// support.
425void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
426 size_t size) {
427 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
428 // We are asked to check a size in HeapWords,
429 // but the memory is mangled in juint words.
430 juint* start = (juint*) (addr + skip_header_HeapWords());
431 juint* end = (juint*) (addr + size);
432 for (juint* slot = start; slot < end; slot += 1) {
433 assert(*slot == badHeapWordVal,
434 "Found non badHeapWordValue in pre-allocation check");
435 }
436 }
437}
438#endif
439
440HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
441 bool is_tlab,
442 bool first_only) {
443 HeapWord* res = NULL;
444
445 if (_young_gen->should_allocate(size, is_tlab)) {
446 res = _young_gen->allocate(size, is_tlab);
447 if (res != NULL || first_only) {
448 return res;
449 }
450 }
451
452 if (_old_gen->should_allocate(size, is_tlab)) {
453 res = _old_gen->allocate(size, is_tlab);
454 }
455
456 return res;
457}
458
459HeapWord* GenCollectedHeap::mem_allocate(size_t size,
460 bool* gc_overhead_limit_was_exceeded) {
461 return mem_allocate_work(size,
462 false /* is_tlab */,
463 gc_overhead_limit_was_exceeded);
464}
465
466bool GenCollectedHeap::must_clear_all_soft_refs() {
467 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
468 _gc_cause == GCCause::_wb_full_gc;
469}
470
471void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
472 bool is_tlab, bool run_verification, bool clear_soft_refs,
473 bool restore_marks_for_biased_locking) {
474 FormatBuffer<> title("Collect gen: %s", gen->short_name());
475 GCTraceTime(Trace, gc, phases) t1(title);
476 TraceCollectorStats tcs(gen->counters());
477 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause());
478
479 gen->stat_record()->invocations++;
480 gen->stat_record()->accumulated_time.start();
481
482 // Must be done anew before each collection because
483 // a previous collection will do mangling and will
484 // change top of some spaces.
485 record_gen_tops_before_GC();
486
487 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
488
489 if (run_verification && VerifyBeforeGC) {
490 HandleMark hm; // Discard invalid handles created during verification
491 Universe::verify("Before GC");
492 }
493 COMPILER2_PRESENT(DerivedPointerTable::clear());
494
495 if (restore_marks_for_biased_locking) {
496 // We perform this mark word preservation work lazily
497 // because it's only at this point that we know whether we
498 // absolutely have to do it; we want to avoid doing it for
499 // scavenge-only collections where it's unnecessary
500 BiasedLocking::preserve_marks();
501 }
502
503 // Do collection work
504 {
505 // Note on ref discovery: For what appear to be historical reasons,
506 // GCH enables and disabled (by enqueing) refs discovery.
507 // In the future this should be moved into the generation's
508 // collect method so that ref discovery and enqueueing concerns
509 // are local to a generation. The collect method could return
510 // an appropriate indication in the case that notification on
511 // the ref lock was needed. This will make the treatment of
512 // weak refs more uniform (and indeed remove such concerns
513 // from GCH). XXX
514
515 HandleMark hm; // Discard invalid handles created during gc
516 save_marks(); // save marks for all gens
517 // We want to discover references, but not process them yet.
518 // This mode is disabled in process_discovered_references if the
519 // generation does some collection work, or in
520 // enqueue_discovered_references if the generation returns
521 // without doing any work.
522 ReferenceProcessor* rp = gen->ref_processor();
523 // If the discovery of ("weak") refs in this generation is
524 // atomic wrt other collectors in this configuration, we
525 // are guaranteed to have empty discovered ref lists.
526 if (rp->discovery_is_atomic()) {
527 rp->enable_discovery();
528 rp->setup_policy(clear_soft_refs);
529 } else {
530 // collect() below will enable discovery as appropriate
531 }
532 gen->collect(full, clear_soft_refs, size, is_tlab);
533 if (!rp->enqueuing_is_done()) {
534 rp->disable_discovery();
535 } else {
536 rp->set_enqueuing_is_done(false);
537 }
538 rp->verify_no_references_recorded();
539 }
540
541 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
542
543 gen->stat_record()->accumulated_time.stop();
544
545 update_gc_stats(gen, full);
546
547 if (run_verification && VerifyAfterGC) {
548 HandleMark hm; // Discard invalid handles created during verification
549 Universe::verify("After GC");
550 }
551}
552
553void GenCollectedHeap::do_collection(bool full,
554 bool clear_all_soft_refs,
555 size_t size,
556 bool is_tlab,
557 GenerationType max_generation) {
558 ResourceMark rm;
559 DEBUG_ONLY(Thread* my_thread = Thread::current();)
560
561 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
562 assert(my_thread->is_VM_thread() ||
563 my_thread->is_ConcurrentGC_thread(),
564 "incorrect thread type capability");
565 assert(Heap_lock->is_locked(),
566 "the requesting thread should have the Heap_lock");
567 guarantee(!is_gc_active(), "collection is not reentrant");
568
569 if (GCLocker::check_active_before_gc()) {
570 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
571 }
572
573 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
574 soft_ref_policy()->should_clear_all_soft_refs();
575
576 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy());
577
578 const size_t metadata_prev_used = MetaspaceUtils::used_bytes();
579
580
581 FlagSetting fl(_is_gc_active, true);
582
583 bool complete = full && (max_generation == OldGen);
584 bool old_collects_young = complete && !ScavengeBeforeFullGC;
585 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
586
587 size_t young_prev_used = _young_gen->used();
588 size_t old_prev_used = _old_gen->used();
589
590 bool run_verification = total_collections() >= VerifyGCStartAt;
591 bool prepared_for_verification = false;
592 bool do_full_collection = false;
593
594 if (do_young_collection) {
595 GCIdMark gc_id_mark;
596 GCTraceCPUTime tcpu;
597 GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true);
598
599 print_heap_before_gc();
600
601 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
602 prepare_for_verify();
603 prepared_for_verification = true;
604 }
605
606 gc_prologue(complete);
607 increment_total_collections(complete);
608
609 collect_generation(_young_gen,
610 full,
611 size,
612 is_tlab,
613 run_verification && VerifyGCLevel <= 0,
614 do_clear_all_soft_refs,
615 false);
616
617 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
618 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
619 // Allocation request was met by young GC.
620 size = 0;
621 }
622
623 // Ask if young collection is enough. If so, do the final steps for young collection,
624 // and fallthrough to the end.
625 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
626 if (!do_full_collection) {
627 // Adjust generation sizes.
628 _young_gen->compute_new_size();
629
630 print_heap_change(young_prev_used, old_prev_used);
631 MetaspaceUtils::print_metaspace_change(metadata_prev_used);
632
633 // Track memory usage and detect low memory after GC finishes
634 MemoryService::track_memory_usage();
635
636 gc_epilogue(complete);
637 }
638
639 print_heap_after_gc();
640
641 } else {
642 // No young collection, ask if we need to perform Full collection.
643 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
644 }
645
646 if (do_full_collection) {
647 GCIdMark gc_id_mark;
648 GCTraceCPUTime tcpu;
649 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
650
651 print_heap_before_gc();
652
653 if (!prepared_for_verification && run_verification &&
654 VerifyGCLevel <= 1 && VerifyBeforeGC) {
655 prepare_for_verify();
656 }
657
658 if (!do_young_collection) {
659 gc_prologue(complete);
660 increment_total_collections(complete);
661 }
662
663 // Accounting quirk: total full collections would be incremented when "complete"
664 // is set, by calling increment_total_collections above. However, we also need to
665 // account Full collections that had "complete" unset.
666 if (!complete) {
667 increment_total_full_collections();
668 }
669
670 collect_generation(_old_gen,
671 full,
672 size,
673 is_tlab,
674 run_verification && VerifyGCLevel <= 1,
675 do_clear_all_soft_refs,
676 true);
677
678 // Adjust generation sizes.
679 _old_gen->compute_new_size();
680 _young_gen->compute_new_size();
681
682 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
683 ClassLoaderDataGraph::purge();
684 MetaspaceUtils::verify_metrics();
685 // Resize the metaspace capacity after full collections
686 MetaspaceGC::compute_new_size();
687 update_full_collections_completed();
688
689 print_heap_change(young_prev_used, old_prev_used);
690 MetaspaceUtils::print_metaspace_change(metadata_prev_used);
691
692 // Track memory usage and detect low memory after GC finishes
693 MemoryService::track_memory_usage();
694
695 // Need to tell the epilogue code we are done with Full GC, regardless what was
696 // the initial value for "complete" flag.
697 gc_epilogue(true);
698
699 BiasedLocking::restore_marks();
700
701 print_heap_after_gc();
702 }
703
704#ifdef TRACESPINNING
705 ParallelTaskTerminator::print_termination_counts();
706#endif
707}
708
709bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab,
710 GenCollectedHeap::GenerationType max_gen) const {
711 return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab);
712}
713
714void GenCollectedHeap::register_nmethod(nmethod* nm) {
715 ScavengableNMethods::register_nmethod(nm);
716}
717
718void GenCollectedHeap::unregister_nmethod(nmethod* nm) {
719 ScavengableNMethods::unregister_nmethod(nm);
720}
721
722void GenCollectedHeap::verify_nmethod(nmethod* nm) {
723 ScavengableNMethods::verify_nmethod(nm);
724}
725
726void GenCollectedHeap::flush_nmethod(nmethod* nm) {
727 // Do nothing.
728}
729
730void GenCollectedHeap::prune_scavengable_nmethods() {
731 ScavengableNMethods::prune_nmethods();
732}
733
734HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
735 GCCauseSetter x(this, GCCause::_allocation_failure);
736 HeapWord* result = NULL;
737
738 assert(size != 0, "Precondition violated");
739 if (GCLocker::is_active_and_needs_gc()) {
740 // GC locker is active; instead of a collection we will attempt
741 // to expand the heap, if there's room for expansion.
742 if (!is_maximal_no_gc()) {
743 result = expand_heap_and_allocate(size, is_tlab);
744 }
745 return result; // Could be null if we are out of space.
746 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) {
747 // Do an incremental collection.
748 do_collection(false, // full
749 false, // clear_all_soft_refs
750 size, // size
751 is_tlab, // is_tlab
752 GenCollectedHeap::OldGen); // max_generation
753 } else {
754 log_trace(gc)(" :: Trying full because partial may fail :: ");
755 // Try a full collection; see delta for bug id 6266275
756 // for the original code and why this has been simplified
757 // with from-space allocation criteria modified and
758 // such allocation moved out of the safepoint path.
759 do_collection(true, // full
760 false, // clear_all_soft_refs
761 size, // size
762 is_tlab, // is_tlab
763 GenCollectedHeap::OldGen); // max_generation
764 }
765
766 result = attempt_allocation(size, is_tlab, false /*first_only*/);
767
768 if (result != NULL) {
769 assert(is_in_reserved(result), "result not in heap");
770 return result;
771 }
772
773 // OK, collection failed, try expansion.
774 result = expand_heap_and_allocate(size, is_tlab);
775 if (result != NULL) {
776 return result;
777 }
778
779 // If we reach this point, we're really out of memory. Try every trick
780 // we can to reclaim memory. Force collection of soft references. Force
781 // a complete compaction of the heap. Any additional methods for finding
782 // free memory should be here, especially if they are expensive. If this
783 // attempt fails, an OOM exception will be thrown.
784 {
785 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
786
787 do_collection(true, // full
788 true, // clear_all_soft_refs
789 size, // size
790 is_tlab, // is_tlab
791 GenCollectedHeap::OldGen); // max_generation
792 }
793
794 result = attempt_allocation(size, is_tlab, false /* first_only */);
795 if (result != NULL) {
796 assert(is_in_reserved(result), "result not in heap");
797 return result;
798 }
799
800 assert(!soft_ref_policy()->should_clear_all_soft_refs(),
801 "Flag should have been handled and cleared prior to this point");
802
803 // What else? We might try synchronous finalization later. If the total
804 // space available is large enough for the allocation, then a more
805 // complete compaction phase than we've tried so far might be
806 // appropriate.
807 return NULL;
808}
809
810#ifdef ASSERT
811class AssertNonScavengableClosure: public OopClosure {
812public:
813 virtual void do_oop(oop* p) {
814 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
815 "Referent should not be scavengable."); }
816 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
817};
818static AssertNonScavengableClosure assert_is_non_scavengable_closure;
819#endif
820
821void GenCollectedHeap::process_roots(StrongRootsScope* scope,
822 ScanningOption so,
823 OopClosure* strong_roots,
824 CLDClosure* strong_cld_closure,
825 CLDClosure* weak_cld_closure,
826 CodeBlobToOopClosure* code_roots) {
827 // General roots.
828 assert(code_roots != NULL, "code root closure should always be set");
829 // _n_termination for _process_strong_tasks should be set up stream
830 // in a method not running in a GC worker. Otherwise the GC worker
831 // could be trying to change the termination condition while the task
832 // is executing in another GC worker.
833
834 if (_process_strong_tasks->try_claim_task(GCH_PS_ClassLoaderDataGraph_oops_do)) {
835 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
836 }
837
838 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
839 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
840
841 bool is_par = scope->n_threads() > 1;
842 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
843
844 if (_process_strong_tasks->try_claim_task(GCH_PS_Universe_oops_do)) {
845 Universe::oops_do(strong_roots);
846 }
847 // Global (strong) JNI handles
848 if (_process_strong_tasks->try_claim_task(GCH_PS_JNIHandles_oops_do)) {
849 JNIHandles::oops_do(strong_roots);
850 }
851
852 if (_process_strong_tasks->try_claim_task(GCH_PS_ObjectSynchronizer_oops_do)) {
853 ObjectSynchronizer::oops_do(strong_roots);
854 }
855 if (_process_strong_tasks->try_claim_task(GCH_PS_Management_oops_do)) {
856 Management::oops_do(strong_roots);
857 }
858 if (_process_strong_tasks->try_claim_task(GCH_PS_jvmti_oops_do)) {
859 JvmtiExport::oops_do(strong_roots);
860 }
861#if INCLUDE_AOT
862 if (UseAOT && _process_strong_tasks->try_claim_task(GCH_PS_aot_oops_do)) {
863 AOTLoader::oops_do(strong_roots);
864 }
865#endif
866#if INCLUDE_JVMCI
867 if (EnableJVMCI && _process_strong_tasks->try_claim_task(GCH_PS_jvmci_oops_do)) {
868 JVMCI::oops_do(strong_roots);
869 }
870#endif
871 if (_process_strong_tasks->try_claim_task(GCH_PS_SystemDictionary_oops_do)) {
872 SystemDictionary::oops_do(strong_roots);
873 }
874
875 if (_process_strong_tasks->try_claim_task(GCH_PS_CodeCache_oops_do)) {
876 if (so & SO_ScavengeCodeCache) {
877 assert(code_roots != NULL, "must supply closure for code cache");
878
879 // We only visit parts of the CodeCache when scavenging.
880 ScavengableNMethods::nmethods_do(code_roots);
881 }
882 if (so & SO_AllCodeCache) {
883 assert(code_roots != NULL, "must supply closure for code cache");
884
885 // CMSCollector uses this to do intermediate-strength collections.
886 // We scan the entire code cache, since CodeCache::do_unloading is not called.
887 CodeCache::blobs_do(code_roots);
888 }
889 // Verify that the code cache contents are not subject to
890 // movement by a scavenging collection.
891 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
892 DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
893 }
894}
895
896void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
897 OopsInGenClosure* root_closure,
898 OopsInGenClosure* old_gen_closure,
899 CLDClosure* cld_closure) {
900 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
901
902 process_roots(scope, SO_ScavengeCodeCache, root_closure,
903 cld_closure, cld_closure, &mark_code_closure);
904
905 if (_process_strong_tasks->try_claim_task(GCH_PS_younger_gens)) {
906 root_closure->reset_generation();
907 }
908
909 // When collection is parallel, all threads get to cooperate to do
910 // old generation scanning.
911 old_gen_closure->set_generation(_old_gen);
912 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
913 old_gen_closure->reset_generation();
914
915 _process_strong_tasks->all_tasks_completed(scope->n_threads());
916}
917
918void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
919 bool is_adjust_phase,
920 ScanningOption so,
921 bool only_strong_roots,
922 OopsInGenClosure* root_closure,
923 CLDClosure* cld_closure) {
924 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
925 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
926
927 process_roots(scope, so, root_closure, cld_closure, weak_cld_closure, &mark_code_closure);
928 _process_strong_tasks->all_tasks_completed(scope->n_threads());
929}
930
931void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
932 WeakProcessor::oops_do(root_closure);
933 _young_gen->ref_processor()->weak_oops_do(root_closure);
934 _old_gen->ref_processor()->weak_oops_do(root_closure);
935}
936
937bool GenCollectedHeap::no_allocs_since_save_marks() {
938 return _young_gen->no_allocs_since_save_marks() &&
939 _old_gen->no_allocs_since_save_marks();
940}
941
942bool GenCollectedHeap::supports_inline_contig_alloc() const {
943 return _young_gen->supports_inline_contig_alloc();
944}
945
946HeapWord* volatile* GenCollectedHeap::top_addr() const {
947 return _young_gen->top_addr();
948}
949
950HeapWord** GenCollectedHeap::end_addr() const {
951 return _young_gen->end_addr();
952}
953
954// public collection interfaces
955
956void GenCollectedHeap::collect(GCCause::Cause cause) {
957 if (cause == GCCause::_wb_young_gc) {
958 // Young collection for the WhiteBox API.
959 collect(cause, YoungGen);
960 } else {
961#ifdef ASSERT
962 if (cause == GCCause::_scavenge_alot) {
963 // Young collection only.
964 collect(cause, YoungGen);
965 } else {
966 // Stop-the-world full collection.
967 collect(cause, OldGen);
968 }
969#else
970 // Stop-the-world full collection.
971 collect(cause, OldGen);
972#endif
973 }
974}
975
976void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
977 // The caller doesn't have the Heap_lock
978 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
979 MutexLocker ml(Heap_lock);
980 collect_locked(cause, max_generation);
981}
982
983void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
984 // The caller has the Heap_lock
985 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
986 collect_locked(cause, OldGen);
987}
988
989// this is the private collection interface
990// The Heap_lock is expected to be held on entry.
991
992void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
993 // Read the GC count while holding the Heap_lock
994 unsigned int gc_count_before = total_collections();
995 unsigned int full_gc_count_before = total_full_collections();
996 {
997 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
998 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
999 cause, max_generation);
1000 VMThread::execute(&op);
1001 }
1002}
1003
1004void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
1005 do_full_collection(clear_all_soft_refs, OldGen);
1006}
1007
1008void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
1009 GenerationType last_generation) {
1010 GenerationType local_last_generation;
1011 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
1012 gc_cause() == GCCause::_gc_locker) {
1013 local_last_generation = YoungGen;
1014 } else {
1015 local_last_generation = last_generation;
1016 }
1017
1018 do_collection(true, // full
1019 clear_all_soft_refs, // clear_all_soft_refs
1020 0, // size
1021 false, // is_tlab
1022 local_last_generation); // last_generation
1023 // Hack XXX FIX ME !!!
1024 // A scavenge may not have been attempted, or may have
1025 // been attempted and failed, because the old gen was too full
1026 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker &&
1027 incremental_collection_will_fail(false /* don't consult_young */)) {
1028 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
1029 // This time allow the old gen to be collected as well
1030 do_collection(true, // full
1031 clear_all_soft_refs, // clear_all_soft_refs
1032 0, // size
1033 false, // is_tlab
1034 OldGen); // last_generation
1035 }
1036}
1037
1038bool GenCollectedHeap::is_in_young(oop p) {
1039 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
1040 assert(result == _young_gen->is_in_reserved(p),
1041 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
1042 return result;
1043}
1044
1045// Returns "TRUE" iff "p" points into the committed areas of the heap.
1046bool GenCollectedHeap::is_in(const void* p) const {
1047 return _young_gen->is_in(p) || _old_gen->is_in(p);
1048}
1049
1050#ifdef ASSERT
1051// Don't implement this by using is_in_young(). This method is used
1052// in some cases to check that is_in_young() is correct.
1053bool GenCollectedHeap::is_in_partial_collection(const void* p) {
1054 assert(is_in_reserved(p) || p == NULL,
1055 "Does not work if address is non-null and outside of the heap");
1056 return p < _young_gen->reserved().end() && p != NULL;
1057}
1058#endif
1059
1060void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) {
1061 _young_gen->oop_iterate(cl);
1062 _old_gen->oop_iterate(cl);
1063}
1064
1065void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
1066 _young_gen->object_iterate(cl);
1067 _old_gen->object_iterate(cl);
1068}
1069
1070void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
1071 _young_gen->safe_object_iterate(cl);
1072 _old_gen->safe_object_iterate(cl);
1073}
1074
1075Space* GenCollectedHeap::space_containing(const void* addr) const {
1076 Space* res = _young_gen->space_containing(addr);
1077 if (res != NULL) {
1078 return res;
1079 }
1080 res = _old_gen->space_containing(addr);
1081 assert(res != NULL, "Could not find containing space");
1082 return res;
1083}
1084
1085HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1086 assert(is_in_reserved(addr), "block_start of address outside of heap");
1087 if (_young_gen->is_in_reserved(addr)) {
1088 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
1089 return _young_gen->block_start(addr);
1090 }
1091
1092 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1093 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
1094 return _old_gen->block_start(addr);
1095}
1096
1097bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1098 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1099 assert(block_start(addr) == addr, "addr must be a block start");
1100 if (_young_gen->is_in_reserved(addr)) {
1101 return _young_gen->block_is_obj(addr);
1102 }
1103
1104 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1105 return _old_gen->block_is_obj(addr);
1106}
1107
1108bool GenCollectedHeap::supports_tlab_allocation() const {
1109 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1110 return _young_gen->supports_tlab_allocation();
1111}
1112
1113size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1114 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1115 if (_young_gen->supports_tlab_allocation()) {
1116 return _young_gen->tlab_capacity();
1117 }
1118 return 0;
1119}
1120
1121size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1122 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1123 if (_young_gen->supports_tlab_allocation()) {
1124 return _young_gen->tlab_used();
1125 }
1126 return 0;
1127}
1128
1129size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1130 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1131 if (_young_gen->supports_tlab_allocation()) {
1132 return _young_gen->unsafe_max_tlab_alloc();
1133 }
1134 return 0;
1135}
1136
1137HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size,
1138 size_t requested_size,
1139 size_t* actual_size) {
1140 bool gc_overhead_limit_was_exceeded;
1141 HeapWord* result = mem_allocate_work(requested_size /* size */,
1142 true /* is_tlab */,
1143 &gc_overhead_limit_was_exceeded);
1144 if (result != NULL) {
1145 *actual_size = requested_size;
1146 }
1147
1148 return result;
1149}
1150
1151// Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1152// from the list headed by "*prev_ptr".
1153static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1154 bool first = true;
1155 size_t min_size = 0; // "first" makes this conceptually infinite.
1156 ScratchBlock **smallest_ptr, *smallest;
1157 ScratchBlock *cur = *prev_ptr;
1158 while (cur) {
1159 assert(*prev_ptr == cur, "just checking");
1160 if (first || cur->num_words < min_size) {
1161 smallest_ptr = prev_ptr;
1162 smallest = cur;
1163 min_size = smallest->num_words;
1164 first = false;
1165 }
1166 prev_ptr = &cur->next;
1167 cur = cur->next;
1168 }
1169 smallest = *smallest_ptr;
1170 *smallest_ptr = smallest->next;
1171 return smallest;
1172}
1173
1174// Sort the scratch block list headed by res into decreasing size order,
1175// and set "res" to the result.
1176static void sort_scratch_list(ScratchBlock*& list) {
1177 ScratchBlock* sorted = NULL;
1178 ScratchBlock* unsorted = list;
1179 while (unsorted) {
1180 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1181 smallest->next = sorted;
1182 sorted = smallest;
1183 }
1184 list = sorted;
1185}
1186
1187ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1188 size_t max_alloc_words) {
1189 ScratchBlock* res = NULL;
1190 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1191 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1192 sort_scratch_list(res);
1193 return res;
1194}
1195
1196void GenCollectedHeap::release_scratch() {
1197 _young_gen->reset_scratch();
1198 _old_gen->reset_scratch();
1199}
1200
1201class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1202 void do_generation(Generation* gen) {
1203 gen->prepare_for_verify();
1204 }
1205};
1206
1207void GenCollectedHeap::prepare_for_verify() {
1208 ensure_parsability(false); // no need to retire TLABs
1209 GenPrepareForVerifyClosure blk;
1210 generation_iterate(&blk, false);
1211}
1212
1213void GenCollectedHeap::generation_iterate(GenClosure* cl,
1214 bool old_to_young) {
1215 if (old_to_young) {
1216 cl->do_generation(_old_gen);
1217 cl->do_generation(_young_gen);
1218 } else {
1219 cl->do_generation(_young_gen);
1220 cl->do_generation(_old_gen);
1221 }
1222}
1223
1224bool GenCollectedHeap::is_maximal_no_gc() const {
1225 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1226}
1227
1228void GenCollectedHeap::save_marks() {
1229 _young_gen->save_marks();
1230 _old_gen->save_marks();
1231}
1232
1233GenCollectedHeap* GenCollectedHeap::heap() {
1234 CollectedHeap* heap = Universe::heap();
1235 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1236 assert(heap->kind() == CollectedHeap::Serial ||
1237 heap->kind() == CollectedHeap::CMS, "Invalid name");
1238 return (GenCollectedHeap*) heap;
1239}
1240
1241#if INCLUDE_SERIALGC
1242void GenCollectedHeap::prepare_for_compaction() {
1243 // Start by compacting into same gen.
1244 CompactPoint cp(_old_gen);
1245 _old_gen->prepare_for_compaction(&cp);
1246 _young_gen->prepare_for_compaction(&cp);
1247}
1248#endif // INCLUDE_SERIALGC
1249
1250void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1251 log_debug(gc, verify)("%s", _old_gen->name());
1252 _old_gen->verify();
1253
1254 log_debug(gc, verify)("%s", _old_gen->name());
1255 _young_gen->verify();
1256
1257 log_debug(gc, verify)("RemSet");
1258 rem_set()->verify();
1259}
1260
1261void GenCollectedHeap::print_on(outputStream* st) const {
1262 _young_gen->print_on(st);
1263 _old_gen->print_on(st);
1264 MetaspaceUtils::print_on(st);
1265}
1266
1267void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1268}
1269
1270void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1271}
1272
1273void GenCollectedHeap::print_tracing_info() const {
1274 if (log_is_enabled(Debug, gc, heap, exit)) {
1275 LogStreamHandle(Debug, gc, heap, exit) lsh;
1276 _young_gen->print_summary_info_on(&lsh);
1277 _old_gen->print_summary_info_on(&lsh);
1278 }
1279}
1280
1281void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const {
1282 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1283 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K);
1284 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1285 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K);
1286}
1287
1288class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1289 private:
1290 bool _full;
1291 public:
1292 void do_generation(Generation* gen) {
1293 gen->gc_prologue(_full);
1294 }
1295 GenGCPrologueClosure(bool full) : _full(full) {};
1296};
1297
1298void GenCollectedHeap::gc_prologue(bool full) {
1299 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1300
1301 // Fill TLAB's and such
1302 ensure_parsability(true); // retire TLABs
1303
1304 // Walk generations
1305 GenGCPrologueClosure blk(full);
1306 generation_iterate(&blk, false); // not old-to-young.
1307};
1308
1309class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1310 private:
1311 bool _full;
1312 public:
1313 void do_generation(Generation* gen) {
1314 gen->gc_epilogue(_full);
1315 }
1316 GenGCEpilogueClosure(bool full) : _full(full) {};
1317};
1318
1319void GenCollectedHeap::gc_epilogue(bool full) {
1320#if COMPILER2_OR_JVMCI
1321 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1322 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1323 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1324#endif // COMPILER2_OR_JVMCI
1325
1326 resize_all_tlabs();
1327
1328 GenGCEpilogueClosure blk(full);
1329 generation_iterate(&blk, false); // not old-to-young.
1330
1331 if (!CleanChunkPoolAsync) {
1332 Chunk::clean_chunk_pool();
1333 }
1334
1335 MetaspaceCounters::update_performance_counters();
1336 CompressedClassSpaceCounters::update_performance_counters();
1337};
1338
1339#ifndef PRODUCT
1340class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1341 private:
1342 public:
1343 void do_generation(Generation* gen) {
1344 gen->record_spaces_top();
1345 }
1346};
1347
1348void GenCollectedHeap::record_gen_tops_before_GC() {
1349 if (ZapUnusedHeapArea) {
1350 GenGCSaveTopsBeforeGCClosure blk;
1351 generation_iterate(&blk, false); // not old-to-young.
1352 }
1353}
1354#endif // not PRODUCT
1355
1356class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1357 public:
1358 void do_generation(Generation* gen) {
1359 gen->ensure_parsability();
1360 }
1361};
1362
1363void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1364 CollectedHeap::ensure_parsability(retire_tlabs);
1365 GenEnsureParsabilityClosure ep_cl;
1366 generation_iterate(&ep_cl, false);
1367}
1368
1369oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1370 oop obj,
1371 size_t obj_size) {
1372 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1373 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1374 HeapWord* result = NULL;
1375
1376 result = old_gen->expand_and_allocate(obj_size, false);
1377
1378 if (result != NULL) {
1379 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1380 }
1381 return oop(result);
1382}
1383
1384class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1385 jlong _time; // in ms
1386 jlong _now; // in ms
1387
1388 public:
1389 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1390
1391 jlong time() { return _time; }
1392
1393 void do_generation(Generation* gen) {
1394 _time = MIN2(_time, gen->time_of_last_gc(_now));
1395 }
1396};
1397
1398jlong GenCollectedHeap::millis_since_last_gc() {
1399 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1400 // provided the underlying platform provides such a time source
1401 // (and it is bug free). So we still have to guard against getting
1402 // back a time later than 'now'.
1403 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1404 GenTimeOfLastGCClosure tolgc_cl(now);
1405 // iterate over generations getting the oldest
1406 // time that a generation was collected
1407 generation_iterate(&tolgc_cl, false);
1408
1409 jlong retVal = now - tolgc_cl.time();
1410 if (retVal < 0) {
1411 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1412 ". returning zero instead.", retVal);
1413 return 0;
1414 }
1415 return retVal;
1416}
1417