1 /*
2 * Copyright (c) 2000, 2021, 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 "classfile/classLoaderDataGraph.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/stringTable.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "compiler/oopMap.hpp"
33 #include "gc/serial/defNewGeneration.hpp"
34 #include "gc/shared/adaptiveSizePolicy.hpp"
35 #include "gc/shared/cardTableBarrierSet.hpp"
36 #include "gc/shared/cardTableRS.hpp"
37 #include "gc/shared/collectedHeap.inline.hpp"
38 #include "gc/shared/collectorCounters.hpp"
39 #include "gc/shared/gcId.hpp"
40 #include "gc/shared/gcLocker.hpp"
41 #include "gc/shared/gcPolicyCounters.hpp"
42 #include "gc/shared/gcTrace.hpp"
43 #include "gc/shared/gcTraceTime.inline.hpp"
44 #include "gc/shared/genArguments.hpp"
45 #include "gc/shared/gcVMOperations.hpp"
46 #include "gc/shared/genCollectedHeap.hpp"
47 #include "gc/shared/genOopClosures.inline.hpp"
48 #include "gc/shared/generationSpec.hpp"
49 #include "gc/shared/gcInitLogger.hpp"
50 #include "gc/shared/locationPrinter.inline.hpp"
51 #include "gc/shared/oopStorage.inline.hpp"
52 #include "gc/shared/oopStorageSet.inline.hpp"
53 #include "gc/shared/oopStorageParState.inline.hpp"
54 #include "gc/shared/scavengableNMethods.hpp"
55 #include "gc/shared/slidingForwarding.hpp"
56 #include "gc/shared/space.hpp"
57 #include "gc/shared/strongRootsScope.hpp"
58 #include "gc/shared/weakProcessor.hpp"
59 #include "gc/shared/workgroup.hpp"
60 #include "memory/iterator.hpp"
61 #include "memory/metaspaceCounters.hpp"
62 #include "memory/metaspaceUtils.hpp"
63 #include "memory/resourceArea.hpp"
64 #include "memory/universe.hpp"
65 #include "oops/oop.inline.hpp"
66 #include "runtime/biasedLocking.hpp"
67 #include "runtime/handles.hpp"
68 #include "runtime/handles.inline.hpp"
69 #include "runtime/java.hpp"
70 #include "runtime/vmThread.hpp"
71 #include "services/memoryService.hpp"
72 #include "utilities/autoRestore.hpp"
73 #include "utilities/debug.hpp"
74 #include "utilities/formatBuffer.hpp"
75 #include "utilities/macros.hpp"
76 #include "utilities/stack.inline.hpp"
77 #include "utilities/vmError.hpp"
78 #if INCLUDE_JVMCI
79 #include "jvmci/jvmci.hpp"
80 #endif
81
82 GenCollectedHeap::GenCollectedHeap(Generation::Name young,
83 Generation::Name old,
84 const char* policy_counters_name) :
85 CollectedHeap(),
86 _young_gen(NULL),
87 _old_gen(NULL),
88 _young_gen_spec(new GenerationSpec(young,
89 NewSize,
90 MaxNewSize,
91 GenAlignment)),
92 _old_gen_spec(new GenerationSpec(old,
93 OldSize,
94 MaxOldSize,
95 GenAlignment)),
96 _rem_set(NULL),
97 _soft_ref_gen_policy(),
98 _size_policy(NULL),
99 _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)),
100 _incremental_collection_failed(false),
101 _full_collections_completed(0),
102 _young_manager(NULL),
103 _old_manager(NULL) {
104 }
105
106 jint GenCollectedHeap::initialize() {
107 // While there are no constraints in the GC code that HeapWordSize
108 // be any particular value, there are multiple other areas in the
109 // system which believe this to be true (e.g. oop->object_size in some
110 // cases incorrectly returns the size in wordSize units rather than
111 // HeapWordSize).
112 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
113
114 // Allocate space for the heap.
115
116 ReservedHeapSpace heap_rs = allocate(HeapAlignment);
117
118 if (!heap_rs.is_reserved()) {
119 vm_shutdown_during_initialization(
120 "Could not reserve enough space for object heap");
121 return JNI_ENOMEM;
122 }
123
124 initialize_reserved_region(heap_rs);
125
126 _rem_set = create_rem_set(heap_rs.region());
127 _rem_set->initialize();
128 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set);
129 bs->initialize();
130 BarrierSet::set_barrier_set(bs);
131
132 ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size());
133 _young_gen = _young_gen_spec->init(young_rs, rem_set());
134 ReservedSpace old_rs = heap_rs.last_part(_young_gen_spec->max_size());
135
136 old_rs = old_rs.first_part(_old_gen_spec->max_size());
137 _old_gen = _old_gen_spec->init(old_rs, rem_set());
138
139 GCInitLogger::print();
140
141 SlidingForwarding::initialize(_reserved, SpaceAlignment / HeapWordSize);
142
143 return JNI_OK;
144 }
145
146 CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) {
147 return new CardTableRS(reserved_region);
148 }
149
150 void GenCollectedHeap::initialize_size_policy(size_t init_eden_size,
151 size_t init_promo_size,
152 size_t init_survivor_size) {
153 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
154 _size_policy = new AdaptiveSizePolicy(init_eden_size,
155 init_promo_size,
156 init_survivor_size,
157 max_gc_pause_sec,
158 GCTimeRatio);
159 }
160
161 ReservedHeapSpace GenCollectedHeap::allocate(size_t alignment) {
162 // Now figure out the total size.
163 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
164 assert(alignment % pageSize == 0, "Must be");
165
166 // Check for overflow.
167 size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size();
168 if (total_reserved < _young_gen_spec->max_size()) {
169 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
170 "the maximum representable size");
171 }
172 assert(total_reserved % alignment == 0,
173 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
174 SIZE_FORMAT, total_reserved, alignment);
175
176 ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment);
177 size_t used_page_size = heap_rs.page_size();
178
179 os::trace_page_sizes("Heap",
180 MinHeapSize,
181 total_reserved,
182 used_page_size,
183 heap_rs.base(),
184 heap_rs.size());
185
186 return heap_rs;
187 }
188
189 class GenIsScavengable : public BoolObjectClosure {
190 public:
191 bool do_object_b(oop obj) {
192 return GenCollectedHeap::heap()->is_in_young(obj);
193 }
194 };
195
196 static GenIsScavengable _is_scavengable;
197
198 void GenCollectedHeap::post_initialize() {
199 CollectedHeap::post_initialize();
200 ref_processing_init();
201
202 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
203
204 initialize_size_policy(def_new_gen->eden()->capacity(),
205 _old_gen->capacity(),
206 def_new_gen->from()->capacity());
207
208 MarkSweep::initialize();
209
210 ScavengableNMethods::initialize(&_is_scavengable);
211 }
212
213 void GenCollectedHeap::ref_processing_init() {
214 _young_gen->ref_processor_init();
215 _old_gen->ref_processor_init();
216 }
217
218 PreGenGCValues GenCollectedHeap::get_pre_gc_values() const {
219 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
220
221 return PreGenGCValues(def_new_gen->used(),
222 def_new_gen->capacity(),
223 def_new_gen->eden()->used(),
224 def_new_gen->eden()->capacity(),
225 def_new_gen->from()->used(),
226 def_new_gen->from()->capacity(),
227 old_gen()->used(),
228 old_gen()->capacity());
229 }
230
231 GenerationSpec* GenCollectedHeap::young_gen_spec() const {
232 return _young_gen_spec;
233 }
234
235 GenerationSpec* GenCollectedHeap::old_gen_spec() const {
236 return _old_gen_spec;
237 }
238
239 size_t GenCollectedHeap::capacity() const {
240 return _young_gen->capacity() + _old_gen->capacity();
241 }
242
243 size_t GenCollectedHeap::used() const {
244 return _young_gen->used() + _old_gen->used();
245 }
246
247 void GenCollectedHeap::save_used_regions() {
248 _old_gen->save_used_region();
249 _young_gen->save_used_region();
250 }
251
252 size_t GenCollectedHeap::max_capacity() const {
253 return _young_gen->max_capacity() + _old_gen->max_capacity();
254 }
255
256 // Update the _full_collections_completed counter
257 // at the end of a stop-world full GC.
258 unsigned int GenCollectedHeap::update_full_collections_completed() {
259 assert(_full_collections_completed <= _total_full_collections,
260 "Can't complete more collections than were started");
261 _full_collections_completed = _total_full_collections;
262 return _full_collections_completed;
263 }
264
265 // Return true if any of the following is true:
266 // . the allocation won't fit into the current young gen heap
267 // . gc locker is occupied (jni critical section)
268 // . heap memory is tight -- the most recent previous collection
269 // was a full collection because a partial collection (would
270 // have) failed and is likely to fail again
271 bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const {
272 size_t young_capacity = _young_gen->capacity_before_gc();
273 return (word_size > heap_word_size(young_capacity))
274 || GCLocker::is_active_and_needs_gc()
275 || incremental_collection_failed();
276 }
277
278 HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) {
279 HeapWord* result = NULL;
280 if (_old_gen->should_allocate(size, is_tlab)) {
281 result = _old_gen->expand_and_allocate(size, is_tlab);
282 }
283 if (result == NULL) {
284 if (_young_gen->should_allocate(size, is_tlab)) {
285 result = _young_gen->expand_and_allocate(size, is_tlab);
286 }
287 }
288 assert(result == NULL || is_in_reserved(result), "result not in heap");
289 return result;
290 }
291
292 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size,
293 bool is_tlab,
294 bool* gc_overhead_limit_was_exceeded) {
295 // In general gc_overhead_limit_was_exceeded should be false so
296 // set it so here and reset it to true only if the gc time
297 // limit is being exceeded as checked below.
298 *gc_overhead_limit_was_exceeded = false;
299
300 HeapWord* result = NULL;
301
302 // Loop until the allocation is satisfied, or unsatisfied after GC.
303 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
304
305 // First allocation attempt is lock-free.
306 Generation *young = _young_gen;
307 assert(young->supports_inline_contig_alloc(),
308 "Otherwise, must do alloc within heap lock");
309 if (young->should_allocate(size, is_tlab)) {
310 result = young->par_allocate(size, is_tlab);
311 if (result != NULL) {
312 assert(is_in_reserved(result), "result not in heap");
313 return result;
314 }
315 }
316 uint gc_count_before; // Read inside the Heap_lock locked region.
317 {
318 MutexLocker ml(Heap_lock);
319 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation");
320 // Note that only large objects get a shot at being
321 // allocated in later generations.
322 bool first_only = !should_try_older_generation_allocation(size);
323
324 result = attempt_allocation(size, is_tlab, first_only);
325 if (result != NULL) {
326 assert(is_in_reserved(result), "result not in heap");
327 return result;
328 }
329
330 if (GCLocker::is_active_and_needs_gc()) {
331 if (is_tlab) {
332 return NULL; // Caller will retry allocating individual object.
333 }
334 if (!is_maximal_no_gc()) {
335 // Try and expand heap to satisfy request.
336 result = expand_heap_and_allocate(size, is_tlab);
337 // Result could be null if we are out of space.
338 if (result != NULL) {
339 return result;
340 }
341 }
342
343 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
344 return NULL; // We didn't get to do a GC and we didn't get any memory.
345 }
346
347 // If this thread is not in a jni critical section, we stall
348 // the requestor until the critical section has cleared and
349 // GC allowed. When the critical section clears, a GC is
350 // initiated by the last thread exiting the critical section; so
351 // we retry the allocation sequence from the beginning of the loop,
352 // rather than causing more, now probably unnecessary, GC attempts.
353 JavaThread* jthr = JavaThread::current();
354 if (!jthr->in_critical()) {
355 MutexUnlocker mul(Heap_lock);
356 // Wait for JNI critical section to be exited
357 GCLocker::stall_until_clear();
358 gclocker_stalled_count += 1;
359 continue;
360 } else {
361 if (CheckJNICalls) {
362 fatal("Possible deadlock due to allocating while"
363 " in jni critical section");
364 }
365 return NULL;
366 }
367 }
368
369 // Read the gc count while the heap lock is held.
370 gc_count_before = total_collections();
371 }
372
373 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
374 VMThread::execute(&op);
375 if (op.prologue_succeeded()) {
376 result = op.result();
377 if (op.gc_locked()) {
378 assert(result == NULL, "must be NULL if gc_locked() is true");
379 continue; // Retry and/or stall as necessary.
380 }
381
382 // Allocation has failed and a collection
383 // has been done. If the gc time limit was exceeded the
384 // this time, return NULL so that an out-of-memory
385 // will be thrown. Clear gc_overhead_limit_exceeded
386 // so that the overhead exceeded does not persist.
387
388 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
389 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear();
390
391 if (limit_exceeded && softrefs_clear) {
392 *gc_overhead_limit_was_exceeded = true;
393 size_policy()->set_gc_overhead_limit_exceeded(false);
394 if (op.result() != NULL) {
395 CollectedHeap::fill_with_object(op.result(), size);
396 }
397 return NULL;
398 }
399 assert(result == NULL || is_in_reserved(result),
400 "result not in heap");
401 return result;
402 }
403
404 // Give a warning if we seem to be looping forever.
405 if ((QueuedAllocationWarningCount > 0) &&
406 (try_count % QueuedAllocationWarningCount == 0)) {
407 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times,"
408 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : "");
409 }
410 }
411 }
412
413 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
414 bool is_tlab,
415 bool first_only) {
416 HeapWord* res = NULL;
417
418 if (_young_gen->should_allocate(size, is_tlab)) {
419 res = _young_gen->allocate(size, is_tlab);
420 if (res != NULL || first_only) {
421 return res;
422 }
423 }
424
425 if (_old_gen->should_allocate(size, is_tlab)) {
426 res = _old_gen->allocate(size, is_tlab);
427 }
428
429 return res;
430 }
431
432 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
433 bool* gc_overhead_limit_was_exceeded) {
434 return mem_allocate_work(size,
435 false /* is_tlab */,
436 gc_overhead_limit_was_exceeded);
437 }
438
439 bool GenCollectedHeap::must_clear_all_soft_refs() {
440 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
441 _gc_cause == GCCause::_wb_full_gc;
442 }
443
444 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
445 bool is_tlab, bool run_verification, bool clear_soft_refs,
446 bool restore_marks_for_biased_locking) {
447 FormatBuffer<> title("Collect gen: %s", gen->short_name());
448 GCTraceTime(Trace, gc, phases) t1(title);
449 TraceCollectorStats tcs(gen->counters());
450 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause());
451
452 gen->stat_record()->invocations++;
453 gen->stat_record()->accumulated_time.start();
454
455 // Must be done anew before each collection because
456 // a previous collection will do mangling and will
457 // change top of some spaces.
458 record_gen_tops_before_GC();
459
460 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
461
462 if (run_verification && VerifyBeforeGC) {
463 Universe::verify("Before GC");
464 }
465 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear());
466
467 if (restore_marks_for_biased_locking) {
468 // We perform this mark word preservation work lazily
469 // because it's only at this point that we know whether we
470 // absolutely have to do it; we want to avoid doing it for
471 // scavenge-only collections where it's unnecessary
472 BiasedLocking::preserve_marks();
473 }
474
475 // Do collection work
476 {
477 // Note on ref discovery: For what appear to be historical reasons,
478 // GCH enables and disabled (by enqueing) refs discovery.
479 // In the future this should be moved into the generation's
480 // collect method so that ref discovery and enqueueing concerns
481 // are local to a generation. The collect method could return
482 // an appropriate indication in the case that notification on
483 // the ref lock was needed. This will make the treatment of
484 // weak refs more uniform (and indeed remove such concerns
485 // from GCH). XXX
486
487 save_marks(); // save marks for all gens
488 // We want to discover references, but not process them yet.
489 // This mode is disabled in process_discovered_references if the
490 // generation does some collection work, or in
491 // enqueue_discovered_references if the generation returns
492 // without doing any work.
493 ReferenceProcessor* rp = gen->ref_processor();
494 // If the discovery of ("weak") refs in this generation is
495 // atomic wrt other collectors in this configuration, we
496 // are guaranteed to have empty discovered ref lists.
497 if (rp->discovery_is_atomic()) {
498 rp->enable_discovery();
499 rp->setup_policy(clear_soft_refs);
500 } else {
501 // collect() below will enable discovery as appropriate
502 }
503 gen->collect(full, clear_soft_refs, size, is_tlab);
504 if (!rp->enqueuing_is_done()) {
505 rp->disable_discovery();
506 } else {
507 rp->set_enqueuing_is_done(false);
508 }
509 rp->verify_no_references_recorded();
510 }
511
512 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers());
513
514 gen->stat_record()->accumulated_time.stop();
515
516 update_gc_stats(gen, full);
517
518 if (run_verification && VerifyAfterGC) {
519 Universe::verify("After GC");
520 }
521 }
522
523 void GenCollectedHeap::do_collection(bool full,
524 bool clear_all_soft_refs,
525 size_t size,
526 bool is_tlab,
527 GenerationType max_generation) {
528 ResourceMark rm;
529 DEBUG_ONLY(Thread* my_thread = Thread::current();)
530
531 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
532 assert(my_thread->is_VM_thread(), "only VM thread");
533 assert(Heap_lock->is_locked(),
534 "the requesting thread should have the Heap_lock");
535 guarantee(!is_gc_active(), "collection is not reentrant");
536
537 if (GCLocker::check_active_before_gc()) {
538 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
539 }
540
541 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
542 soft_ref_policy()->should_clear_all_soft_refs();
543
544 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy());
545
546 AutoModifyRestore<bool> temporarily(_is_gc_active, true);
547
548 bool complete = full && (max_generation == OldGen);
549 bool old_collects_young = complete && !ScavengeBeforeFullGC;
550 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
551
552 const PreGenGCValues pre_gc_values = get_pre_gc_values();
553
554 bool run_verification = total_collections() >= VerifyGCStartAt;
555 bool prepared_for_verification = false;
556 bool do_full_collection = false;
557
558 if (do_young_collection) {
559 GCIdMark gc_id_mark;
560 GCTraceCPUTime tcpu;
561 GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true);
562
563 print_heap_before_gc();
564
565 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
566 prepare_for_verify();
567 prepared_for_verification = true;
568 }
569
570 gc_prologue(complete);
571 increment_total_collections(complete);
572
573 collect_generation(_young_gen,
574 full,
575 size,
576 is_tlab,
577 run_verification && VerifyGCLevel <= 0,
578 do_clear_all_soft_refs,
579 false);
580
581 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
582 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
583 // Allocation request was met by young GC.
584 size = 0;
585 }
586
587 // Ask if young collection is enough. If so, do the final steps for young collection,
588 // and fallthrough to the end.
589 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
590 if (!do_full_collection) {
591 // Adjust generation sizes.
592 _young_gen->compute_new_size();
593
594 print_heap_change(pre_gc_values);
595
596 // Track memory usage and detect low memory after GC finishes
597 MemoryService::track_memory_usage();
598
599 gc_epilogue(complete);
600 }
601
602 print_heap_after_gc();
603
604 } else {
605 // No young collection, ask if we need to perform Full collection.
606 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
607 }
608
609 if (do_full_collection) {
610 GCIdMark gc_id_mark;
611 GCTraceCPUTime tcpu;
612 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
613
614 print_heap_before_gc();
615
616 if (!prepared_for_verification && run_verification &&
617 VerifyGCLevel <= 1 && VerifyBeforeGC) {
618 prepare_for_verify();
619 }
620
621 if (!do_young_collection) {
622 gc_prologue(complete);
623 increment_total_collections(complete);
624 }
625
626 // Accounting quirk: total full collections would be incremented when "complete"
627 // is set, by calling increment_total_collections above. However, we also need to
628 // account Full collections that had "complete" unset.
629 if (!complete) {
630 increment_total_full_collections();
631 }
632
633 collect_generation(_old_gen,
634 full,
635 size,
636 is_tlab,
637 run_verification && VerifyGCLevel <= 1,
638 do_clear_all_soft_refs,
639 true);
640
641 // Adjust generation sizes.
642 _old_gen->compute_new_size();
643 _young_gen->compute_new_size();
644
645 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
646 ClassLoaderDataGraph::purge(/*at_safepoint*/true);
647 DEBUG_ONLY(MetaspaceUtils::verify();)
648 // Resize the metaspace capacity after full collections
649 MetaspaceGC::compute_new_size();
650 update_full_collections_completed();
651
652 print_heap_change(pre_gc_values);
653
654 // Track memory usage and detect low memory after GC finishes
655 MemoryService::track_memory_usage();
656
657 // Need to tell the epilogue code we are done with Full GC, regardless what was
658 // the initial value for "complete" flag.
659 gc_epilogue(true);
660
661 BiasedLocking::restore_marks();
662
663 print_heap_after_gc();
664 }
665 }
666
667 bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab,
668 GenCollectedHeap::GenerationType max_gen) const {
669 return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab);
670 }
671
672 void GenCollectedHeap::register_nmethod(nmethod* nm) {
673 ScavengableNMethods::register_nmethod(nm);
674 }
675
676 void GenCollectedHeap::unregister_nmethod(nmethod* nm) {
677 ScavengableNMethods::unregister_nmethod(nm);
678 }
679
680 void GenCollectedHeap::verify_nmethod(nmethod* nm) {
681 ScavengableNMethods::verify_nmethod(nm);
682 }
683
684 void GenCollectedHeap::flush_nmethod(nmethod* nm) {
685 // Do nothing.
686 }
687
688 void GenCollectedHeap::prune_scavengable_nmethods() {
689 ScavengableNMethods::prune_nmethods();
690 }
691
692 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
693 GCCauseSetter x(this, GCCause::_allocation_failure);
694 HeapWord* result = NULL;
695
696 assert(size != 0, "Precondition violated");
697 if (GCLocker::is_active_and_needs_gc()) {
698 // GC locker is active; instead of a collection we will attempt
699 // to expand the heap, if there's room for expansion.
700 if (!is_maximal_no_gc()) {
701 result = expand_heap_and_allocate(size, is_tlab);
702 }
703 return result; // Could be null if we are out of space.
704 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) {
705 // Do an incremental collection.
706 do_collection(false, // full
707 false, // clear_all_soft_refs
708 size, // size
709 is_tlab, // is_tlab
710 GenCollectedHeap::OldGen); // max_generation
711 } else {
712 log_trace(gc)(" :: Trying full because partial may fail :: ");
713 // Try a full collection; see delta for bug id 6266275
714 // for the original code and why this has been simplified
715 // with from-space allocation criteria modified and
716 // such allocation moved out of the safepoint path.
717 do_collection(true, // full
718 false, // clear_all_soft_refs
719 size, // size
720 is_tlab, // is_tlab
721 GenCollectedHeap::OldGen); // max_generation
722 }
723
724 result = attempt_allocation(size, is_tlab, false /*first_only*/);
725
726 if (result != NULL) {
727 assert(is_in_reserved(result), "result not in heap");
728 return result;
729 }
730
731 // OK, collection failed, try expansion.
732 result = expand_heap_and_allocate(size, is_tlab);
733 if (result != NULL) {
734 return result;
735 }
736
737 // If we reach this point, we're really out of memory. Try every trick
738 // we can to reclaim memory. Force collection of soft references. Force
739 // a complete compaction of the heap. Any additional methods for finding
740 // free memory should be here, especially if they are expensive. If this
741 // attempt fails, an OOM exception will be thrown.
742 {
743 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
744
745 do_collection(true, // full
746 true, // clear_all_soft_refs
747 size, // size
748 is_tlab, // is_tlab
749 GenCollectedHeap::OldGen); // max_generation
750 }
751
752 result = attempt_allocation(size, is_tlab, false /* first_only */);
753 if (result != NULL) {
754 assert(is_in_reserved(result), "result not in heap");
755 return result;
756 }
757
758 assert(!soft_ref_policy()->should_clear_all_soft_refs(),
759 "Flag should have been handled and cleared prior to this point");
760
761 // What else? We might try synchronous finalization later. If the total
762 // space available is large enough for the allocation, then a more
763 // complete compaction phase than we've tried so far might be
764 // appropriate.
765 return NULL;
766 }
767
768 #ifdef ASSERT
769 class AssertNonScavengableClosure: public OopClosure {
770 public:
771 virtual void do_oop(oop* p) {
772 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
773 "Referent should not be scavengable."); }
774 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
775 };
776 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
777 #endif
778
779 void GenCollectedHeap::process_roots(ScanningOption so,
780 OopClosure* strong_roots,
781 CLDClosure* strong_cld_closure,
782 CLDClosure* weak_cld_closure,
783 CodeBlobToOopClosure* code_roots) {
784 // General roots.
785 assert(code_roots != NULL, "code root closure should always be set");
786
787 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
788
789 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
790 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
791
792 Threads::oops_do(strong_roots, roots_from_code_p);
793
794 OopStorageSet::strong_oops_do(strong_roots);
795
796 if (so & SO_ScavengeCodeCache) {
797 assert(code_roots != NULL, "must supply closure for code cache");
798
799 // We only visit parts of the CodeCache when scavenging.
800 ScavengableNMethods::nmethods_do(code_roots);
801 }
802 if (so & SO_AllCodeCache) {
803 assert(code_roots != NULL, "must supply closure for code cache");
804
805 // CMSCollector uses this to do intermediate-strength collections.
806 // We scan the entire code cache, since CodeCache::do_unloading is not called.
807 CodeCache::blobs_do(code_roots);
808 }
809 // Verify that the code cache contents are not subject to
810 // movement by a scavenging collection.
811 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
812 DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
813 }
814
815 void GenCollectedHeap::full_process_roots(bool is_adjust_phase,
816 ScanningOption so,
817 bool only_strong_roots,
818 OopClosure* root_closure,
819 CLDClosure* cld_closure) {
820 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
821 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
822
823 process_roots(so, root_closure, cld_closure, weak_cld_closure, &mark_code_closure);
824 }
825
826 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
827 WeakProcessor::oops_do(root_closure);
828 _young_gen->ref_processor()->weak_oops_do(root_closure);
829 _old_gen->ref_processor()->weak_oops_do(root_closure);
830 }
831
832 bool GenCollectedHeap::no_allocs_since_save_marks() {
833 return _young_gen->no_allocs_since_save_marks() &&
834 _old_gen->no_allocs_since_save_marks();
835 }
836
837 bool GenCollectedHeap::supports_inline_contig_alloc() const {
838 return _young_gen->supports_inline_contig_alloc();
839 }
840
841 HeapWord* volatile* GenCollectedHeap::top_addr() const {
842 return _young_gen->top_addr();
843 }
844
845 HeapWord** GenCollectedHeap::end_addr() const {
846 return _young_gen->end_addr();
847 }
848
849 // public collection interfaces
850
851 void GenCollectedHeap::collect(GCCause::Cause cause) {
852 if ((cause == GCCause::_wb_young_gc) ||
853 (cause == GCCause::_gc_locker)) {
854 // Young collection for WhiteBox or GCLocker.
855 collect(cause, YoungGen);
856 } else {
857 #ifdef ASSERT
858 if (cause == GCCause::_scavenge_alot) {
859 // Young collection only.
860 collect(cause, YoungGen);
861 } else {
862 // Stop-the-world full collection.
863 collect(cause, OldGen);
864 }
865 #else
866 // Stop-the-world full collection.
867 collect(cause, OldGen);
868 #endif
869 }
870 }
871
872 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
873 // The caller doesn't have the Heap_lock
874 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
875 MutexLocker ml(Heap_lock);
876 collect_locked(cause, max_generation);
877 }
878
879 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
880 // The caller has the Heap_lock
881 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
882 collect_locked(cause, OldGen);
883 }
884
885 // this is the private collection interface
886 // The Heap_lock is expected to be held on entry.
887
888 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
889 // Read the GC count while holding the Heap_lock
890 unsigned int gc_count_before = total_collections();
891 unsigned int full_gc_count_before = total_full_collections();
892
893 if (GCLocker::should_discard(cause, gc_count_before)) {
894 return;
895 }
896
897 {
898 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
899 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
900 cause, max_generation);
901 VMThread::execute(&op);
902 }
903 }
904
905 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
906 do_full_collection(clear_all_soft_refs, OldGen);
907 }
908
909 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
910 GenerationType last_generation) {
911 do_collection(true, // full
912 clear_all_soft_refs, // clear_all_soft_refs
913 0, // size
914 false, // is_tlab
915 last_generation); // last_generation
916 // Hack XXX FIX ME !!!
917 // A scavenge may not have been attempted, or may have
918 // been attempted and failed, because the old gen was too full
919 if (gc_cause() == GCCause::_gc_locker && incremental_collection_failed()) {
920 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
921 // This time allow the old gen to be collected as well
922 do_collection(true, // full
923 clear_all_soft_refs, // clear_all_soft_refs
924 0, // size
925 false, // is_tlab
926 OldGen); // last_generation
927 }
928 }
929
930 bool GenCollectedHeap::is_in_young(oop p) {
931 bool result = cast_from_oop<HeapWord*>(p) < _old_gen->reserved().start();
932 assert(result == _young_gen->is_in_reserved(p),
933 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
934 return result;
935 }
936
937 // Returns "TRUE" iff "p" points into the committed areas of the heap.
938 bool GenCollectedHeap::is_in(const void* p) const {
939 return _young_gen->is_in(p) || _old_gen->is_in(p);
940 }
941
942 #ifdef ASSERT
943 // Don't implement this by using is_in_young(). This method is used
944 // in some cases to check that is_in_young() is correct.
945 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
946 assert(is_in_reserved(p) || p == NULL,
947 "Does not work if address is non-null and outside of the heap");
948 return p < _young_gen->reserved().end() && p != NULL;
949 }
950 #endif
951
952 void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) {
953 _young_gen->oop_iterate(cl);
954 _old_gen->oop_iterate(cl);
955 }
956
957 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
958 _young_gen->object_iterate(cl);
959 _old_gen->object_iterate(cl);
960 }
961
962 Space* GenCollectedHeap::space_containing(const void* addr) const {
963 Space* res = _young_gen->space_containing(addr);
964 if (res != NULL) {
965 return res;
966 }
967 res = _old_gen->space_containing(addr);
968 assert(res != NULL, "Could not find containing space");
969 return res;
970 }
971
972 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
973 assert(is_in_reserved(addr), "block_start of address outside of heap");
974 if (_young_gen->is_in_reserved(addr)) {
975 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
976 return _young_gen->block_start(addr);
977 }
978
979 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
980 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
981 return _old_gen->block_start(addr);
982 }
983
984 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
985 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
986 assert(block_start(addr) == addr, "addr must be a block start");
987 if (_young_gen->is_in_reserved(addr)) {
988 return _young_gen->block_is_obj(addr);
989 }
990
991 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
992 return _old_gen->block_is_obj(addr);
993 }
994
995 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
996 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
997 assert(_young_gen->supports_tlab_allocation(), "Young gen doesn't support TLAB allocation?!");
998 return _young_gen->tlab_capacity();
999 }
1000
1001 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1002 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1003 assert(_young_gen->supports_tlab_allocation(), "Young gen doesn't support TLAB allocation?!");
1004 return _young_gen->tlab_used();
1005 }
1006
1007 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1008 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1009 assert(_young_gen->supports_tlab_allocation(), "Young gen doesn't support TLAB allocation?!");
1010 return _young_gen->unsafe_max_tlab_alloc();
1011 }
1012
1013 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size,
1014 size_t requested_size,
1015 size_t* actual_size) {
1016 bool gc_overhead_limit_was_exceeded;
1017 HeapWord* result = mem_allocate_work(requested_size /* size */,
1018 true /* is_tlab */,
1019 &gc_overhead_limit_was_exceeded);
1020 if (result != NULL) {
1021 *actual_size = requested_size;
1022 }
1023
1024 return result;
1025 }
1026
1027 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1028 // from the list headed by "*prev_ptr".
1029 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1030 bool first = true;
1031 size_t min_size = 0; // "first" makes this conceptually infinite.
1032 ScratchBlock **smallest_ptr, *smallest;
1033 ScratchBlock *cur = *prev_ptr;
1034 while (cur) {
1035 assert(*prev_ptr == cur, "just checking");
1036 if (first || cur->num_words < min_size) {
1037 smallest_ptr = prev_ptr;
1038 smallest = cur;
1039 min_size = smallest->num_words;
1040 first = false;
1041 }
1042 prev_ptr = &cur->next;
1043 cur = cur->next;
1044 }
1045 smallest = *smallest_ptr;
1046 *smallest_ptr = smallest->next;
1047 return smallest;
1048 }
1049
1050 // Sort the scratch block list headed by res into decreasing size order,
1051 // and set "res" to the result.
1052 static void sort_scratch_list(ScratchBlock*& list) {
1053 ScratchBlock* sorted = NULL;
1054 ScratchBlock* unsorted = list;
1055 while (unsorted) {
1056 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1057 smallest->next = sorted;
1058 sorted = smallest;
1059 }
1060 list = sorted;
1061 }
1062
1063 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1064 size_t max_alloc_words) {
1065 ScratchBlock* res = NULL;
1066 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1067 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1068 sort_scratch_list(res);
1069 return res;
1070 }
1071
1072 void GenCollectedHeap::release_scratch() {
1073 _young_gen->reset_scratch();
1074 _old_gen->reset_scratch();
1075 }
1076
1077 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1078 void do_generation(Generation* gen) {
1079 gen->prepare_for_verify();
1080 }
1081 };
1082
1083 void GenCollectedHeap::prepare_for_verify() {
1084 ensure_parsability(false); // no need to retire TLABs
1085 GenPrepareForVerifyClosure blk;
1086 generation_iterate(&blk, false);
1087 }
1088
1089 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1090 bool old_to_young) {
1091 if (old_to_young) {
1092 cl->do_generation(_old_gen);
1093 cl->do_generation(_young_gen);
1094 } else {
1095 cl->do_generation(_young_gen);
1096 cl->do_generation(_old_gen);
1097 }
1098 }
1099
1100 bool GenCollectedHeap::is_maximal_no_gc() const {
1101 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1102 }
1103
1104 void GenCollectedHeap::save_marks() {
1105 _young_gen->save_marks();
1106 _old_gen->save_marks();
1107 }
1108
1109 GenCollectedHeap* GenCollectedHeap::heap() {
1110 // SerialHeap is the only subtype of GenCollectedHeap.
1111 return named_heap<GenCollectedHeap>(CollectedHeap::Serial);
1112 }
1113
1114 #if INCLUDE_SERIALGC
1115 void GenCollectedHeap::prepare_for_compaction() {
1116 // Start by compacting into same gen.
1117 CompactPoint cp(_old_gen);
1118 _old_gen->prepare_for_compaction(&cp);
1119 _young_gen->prepare_for_compaction(&cp);
1120 }
1121 #endif // INCLUDE_SERIALGC
1122
1123 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1124 log_debug(gc, verify)("%s", _old_gen->name());
1125 _old_gen->verify();
1126
1127 log_debug(gc, verify)("%s", _old_gen->name());
1128 _young_gen->verify();
1129
1130 log_debug(gc, verify)("RemSet");
1131 rem_set()->verify();
1132 }
1133
1134 void GenCollectedHeap::print_on(outputStream* st) const {
1135 if (_young_gen != NULL) {
1136 _young_gen->print_on(st);
1137 }
1138 if (_old_gen != NULL) {
1139 _old_gen->print_on(st);
1140 }
1141 MetaspaceUtils::print_on(st);
1142 }
1143
1144 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1145 }
1146
1147 bool GenCollectedHeap::print_location(outputStream* st, void* addr) const {
1148 return BlockLocationPrinter<GenCollectedHeap>::print_location(st, addr);
1149 }
1150
1151 void GenCollectedHeap::print_tracing_info() const {
1152 if (log_is_enabled(Debug, gc, heap, exit)) {
1153 LogStreamHandle(Debug, gc, heap, exit) lsh;
1154 _young_gen->print_summary_info_on(&lsh);
1155 _old_gen->print_summary_info_on(&lsh);
1156 }
1157 }
1158
1159 void GenCollectedHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const {
1160 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
1161
1162 log_info(gc, heap)(HEAP_CHANGE_FORMAT" "
1163 HEAP_CHANGE_FORMAT" "
1164 HEAP_CHANGE_FORMAT,
1165 HEAP_CHANGE_FORMAT_ARGS(def_new_gen->short_name(),
1166 pre_gc_values.young_gen_used(),
1167 pre_gc_values.young_gen_capacity(),
1168 def_new_gen->used(),
1169 def_new_gen->capacity()),
1170 HEAP_CHANGE_FORMAT_ARGS("Eden",
1171 pre_gc_values.eden_used(),
1172 pre_gc_values.eden_capacity(),
1173 def_new_gen->eden()->used(),
1174 def_new_gen->eden()->capacity()),
1175 HEAP_CHANGE_FORMAT_ARGS("From",
1176 pre_gc_values.from_used(),
1177 pre_gc_values.from_capacity(),
1178 def_new_gen->from()->used(),
1179 def_new_gen->from()->capacity()));
1180 log_info(gc, heap)(HEAP_CHANGE_FORMAT,
1181 HEAP_CHANGE_FORMAT_ARGS(old_gen()->short_name(),
1182 pre_gc_values.old_gen_used(),
1183 pre_gc_values.old_gen_capacity(),
1184 old_gen()->used(),
1185 old_gen()->capacity()));
1186 MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes());
1187 }
1188
1189 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1190 private:
1191 bool _full;
1192 public:
1193 void do_generation(Generation* gen) {
1194 gen->gc_prologue(_full);
1195 }
1196 GenGCPrologueClosure(bool full) : _full(full) {};
1197 };
1198
1199 void GenCollectedHeap::gc_prologue(bool full) {
1200 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1201
1202 // Fill TLAB's and such
1203 ensure_parsability(true); // retire TLABs
1204
1205 // Walk generations
1206 GenGCPrologueClosure blk(full);
1207 generation_iterate(&blk, false); // not old-to-young.
1208 };
1209
1210 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1211 private:
1212 bool _full;
1213 public:
1214 void do_generation(Generation* gen) {
1215 gen->gc_epilogue(_full);
1216 }
1217 GenGCEpilogueClosure(bool full) : _full(full) {};
1218 };
1219
1220 void GenCollectedHeap::gc_epilogue(bool full) {
1221 #if COMPILER2_OR_JVMCI
1222 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1223 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1224 guarantee(!CompilerConfig::is_c2_or_jvmci_compiler_enabled() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1225 #endif // COMPILER2_OR_JVMCI
1226
1227 resize_all_tlabs();
1228
1229 GenGCEpilogueClosure blk(full);
1230 generation_iterate(&blk, false); // not old-to-young.
1231
1232 MetaspaceCounters::update_performance_counters();
1233 };
1234
1235 #ifndef PRODUCT
1236 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1237 private:
1238 public:
1239 void do_generation(Generation* gen) {
1240 gen->record_spaces_top();
1241 }
1242 };
1243
1244 void GenCollectedHeap::record_gen_tops_before_GC() {
1245 if (ZapUnusedHeapArea) {
1246 GenGCSaveTopsBeforeGCClosure blk;
1247 generation_iterate(&blk, false); // not old-to-young.
1248 }
1249 }
1250 #endif // not PRODUCT
1251
1252 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1253 public:
1254 void do_generation(Generation* gen) {
1255 gen->ensure_parsability();
1256 }
1257 };
1258
1259 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1260 CollectedHeap::ensure_parsability(retire_tlabs);
1261 GenEnsureParsabilityClosure ep_cl;
1262 generation_iterate(&ep_cl, false);
1263 }
1264
1265 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1266 oop obj,
1267 size_t obj_size) {
1268 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1269 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1270 HeapWord* result = NULL;
1271
1272 result = old_gen->expand_and_allocate(obj_size, false);
1273
1274 if (result != NULL) {
1275 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), result, obj_size);
1276 }
1277 return cast_to_oop(result);
1278 }