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