1 /*
2 * Copyright (c) 2001, 2023, 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/classLoaderData.hpp"
27 #include "classfile/vmClasses.hpp"
28 #include "gc/shared/allocTracer.hpp"
29 #include "gc/shared/barrierSet.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "gc/shared/gcLocker.inline.hpp"
33 #include "gc/shared/gcHeapSummary.hpp"
34 #include "gc/shared/stringdedup/stringDedup.hpp"
35 #include "gc/shared/gcTrace.hpp"
36 #include "gc/shared/gcTraceTime.inline.hpp"
37 #include "gc/shared/gcVMOperations.hpp"
38 #include "gc/shared/gcWhen.hpp"
39 #include "gc/shared/gc_globals.hpp"
40 #include "gc/shared/memAllocator.hpp"
41 #include "gc/shared/tlab_globals.hpp"
42 #include "logging/log.hpp"
43 #include "logging/logStream.hpp"
44 #include "memory/classLoaderMetaspace.hpp"
45 #include "memory/metaspaceUtils.hpp"
46 #include "memory/resourceArea.hpp"
47 #include "memory/universe.hpp"
48 #include "oops/instanceMirrorKlass.hpp"
49 #include "oops/oop.inline.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/init.hpp"
52 #include "runtime/javaThread.hpp"
53 #include "runtime/perfData.hpp"
54 #include "runtime/threadSMR.hpp"
55 #include "runtime/vmThread.hpp"
56 #include "services/heapDumper.hpp"
57 #include "utilities/align.hpp"
58 #include "utilities/copy.hpp"
59 #include "utilities/events.hpp"
60
61 class ClassLoaderData;
62
63 size_t CollectedHeap::_lab_alignment_reserve = SIZE_MAX;
64 Klass* CollectedHeap::_filler_object_klass = nullptr;
65 size_t CollectedHeap::_filler_array_max_size = 0;
66 size_t CollectedHeap::_stack_chunk_max_size = 0;
67
68 class GCMessage : public FormatBuffer<1024> {
69 public:
70 bool is_before;
71 };
72
73 template <>
74 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
75 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
76 st->print_raw(m);
77 }
78
79 class GCHeapLog : public EventLogBase<GCMessage> {
80 private:
81 void log_heap(CollectedHeap* heap, bool before);
82
83 public:
84 GCHeapLog() : EventLogBase<GCMessage>("GC Heap History", "gc") {}
85
86 void log_heap_before(CollectedHeap* heap) {
87 log_heap(heap, true);
88 }
89 void log_heap_after(CollectedHeap* heap) {
90 log_heap(heap, false);
91 }
92 };
93
94 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
95 if (!should_log()) {
96 return;
97 }
98
99 double timestamp = fetch_timestamp();
100 MutexLocker ml(&_mutex, Mutex::_no_safepoint_check_flag);
101 int index = compute_log_index();
102 _records[index].thread = nullptr; // Its the GC thread so it's not that interesting.
103 _records[index].timestamp = timestamp;
104 _records[index].data.is_before = before;
105 stringStream st(_records[index].data.buffer(), _records[index].data.size());
106
107 st.print_cr("{Heap %s GC invocations=%u (full %u):",
108 before ? "before" : "after",
109 heap->total_collections(),
110 heap->total_full_collections());
111
112 heap->print_on(&st);
113 st.print_cr("}");
114 }
115
116 ParallelObjectIterator::ParallelObjectIterator(uint thread_num) :
117 _impl(Universe::heap()->parallel_object_iterator(thread_num))
118 {}
119
120 ParallelObjectIterator::~ParallelObjectIterator() {
121 delete _impl;
122 }
123
124 void ParallelObjectIterator::object_iterate(ObjectClosure* cl, uint worker_id) {
125 _impl->object_iterate(cl, worker_id);
126 }
127
128 size_t CollectedHeap::unused() const {
129 MutexLocker ml(Heap_lock);
130 return capacity() - used();
131 }
132
133 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
134 size_t capacity_in_words = capacity() / HeapWordSize;
135
136 return VirtualSpaceSummary(
137 _reserved.start(), _reserved.start() + capacity_in_words, _reserved.end());
138 }
139
140 GCHeapSummary CollectedHeap::create_heap_summary() {
141 VirtualSpaceSummary heap_space = create_heap_space_summary();
142 return GCHeapSummary(heap_space, used());
143 }
144
145 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
146 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
147 MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType);
148 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
149 MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType);
150 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(),
151 MetaspaceUtils::get_combined_statistics(),
152 ms_chunk_free_list_summary, class_chunk_free_list_summary);
153 }
154
155 bool CollectedHeap::contains_null(const oop* p) const {
156 return *p == nullptr;
157 }
158
159 void CollectedHeap::print_heap_before_gc() {
160 LogTarget(Debug, gc, heap) lt;
161 if (lt.is_enabled()) {
162 LogStream ls(lt);
163 ls.print_cr("Heap before GC invocations=%u (full %u):", total_collections(), total_full_collections());
164 ResourceMark rm;
165 print_on(&ls);
166 }
167
168 if (_gc_heap_log != nullptr) {
169 _gc_heap_log->log_heap_before(this);
170 }
171 }
172
173 void CollectedHeap::print_heap_after_gc() {
174 LogTarget(Debug, gc, heap) lt;
175 if (lt.is_enabled()) {
176 LogStream ls(lt);
177 ls.print_cr("Heap after GC invocations=%u (full %u):", total_collections(), total_full_collections());
178 ResourceMark rm;
179 print_on(&ls);
180 }
181
182 if (_gc_heap_log != nullptr) {
183 _gc_heap_log->log_heap_after(this);
184 }
185 }
186
187 void CollectedHeap::print() const { print_on(tty); }
188
189 void CollectedHeap::print_on_error(outputStream* st) const {
190 st->print_cr("Heap:");
191 print_extended_on(st);
192 st->cr();
193
194 BarrierSet* bs = BarrierSet::barrier_set();
195 if (bs != nullptr) {
196 bs->print_on(st);
197 }
198 }
199
200 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
201 const GCHeapSummary& heap_summary = create_heap_summary();
202 gc_tracer->report_gc_heap_summary(when, heap_summary);
203
204 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
205 gc_tracer->report_metaspace_summary(when, metaspace_summary);
206 }
207
208 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
209 trace_heap(GCWhen::BeforeGC, gc_tracer);
210 }
211
212 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
213 trace_heap(GCWhen::AfterGC, gc_tracer);
214 }
215
216 // Default implementation, for collectors that don't support the feature.
217 bool CollectedHeap::supports_concurrent_gc_breakpoints() const {
218 return false;
219 }
220
221 bool CollectedHeap::is_oop(oop object) const {
222 if (!is_object_aligned(object)) {
223 return false;
224 }
225
226 if (!is_in(object)) {
227 return false;
228 }
229
230 return true;
231 }
232
233 // Memory state functions.
234
235
236 CollectedHeap::CollectedHeap() :
237 _capacity_at_last_gc(0),
238 _used_at_last_gc(0),
239 _is_gc_active(false),
240 _last_whole_heap_examined_time_ns(os::javaTimeNanos()),
241 _total_collections(0),
242 _total_full_collections(0),
243 _gc_cause(GCCause::_no_gc),
244 _gc_lastcause(GCCause::_no_gc)
245 {
246 // If the minimum object size is greater than MinObjAlignment, we can
247 // end up with a shard at the end of the buffer that's smaller than
248 // the smallest object. We can't allow that because the buffer must
249 // look like it's full of objects when we retire it, so we make
250 // sure we have enough space for a filler int array object.
251 size_t min_size = min_dummy_object_size();
252 _lab_alignment_reserve = min_size > (size_t)MinObjAlignment ? align_object_size(min_size) : 0;
253
254 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
255 const size_t elements_per_word = HeapWordSize / sizeof(jint);
256 int header_size_in_bytes = arrayOopDesc::base_offset_in_bytes(T_INT);
257 assert(header_size_in_bytes % sizeof(jint) == 0, "must be aligned to int");
258 int header_size_in_ints = header_size_in_bytes / sizeof(jint);
259 _filler_array_max_size = align_object_size((header_size_in_ints + max_len) / elements_per_word);
260
261 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
262 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
263
264 if (UsePerfData) {
265 EXCEPTION_MARK;
266
267 // create the gc cause jvmstat counters
268 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
269 80, GCCause::to_string(_gc_cause), CHECK);
270
271 _perf_gc_lastcause =
272 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
273 80, GCCause::to_string(_gc_lastcause), CHECK);
274 }
275
276 // Create the ring log
277 if (LogEvents) {
278 _gc_heap_log = new GCHeapLog();
279 } else {
280 _gc_heap_log = nullptr;
281 }
282 }
283
284 // This interface assumes that it's being called by the
285 // vm thread. It collects the heap assuming that the
286 // heap lock is already held and that we are executing in
287 // the context of the vm thread.
288 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
289 Thread* thread = Thread::current();
290 assert(thread->is_VM_thread(), "Precondition#1");
291 assert(Heap_lock->is_locked(), "Precondition#2");
292 GCCauseSetter gcs(this, cause);
293 switch (cause) {
294 case GCCause::_codecache_GC_threshold:
295 case GCCause::_codecache_GC_aggressive:
296 case GCCause::_heap_inspection:
297 case GCCause::_heap_dump:
298 case GCCause::_metadata_GC_threshold: {
299 HandleMark hm(thread);
300 do_full_collection(false); // don't clear all soft refs
301 break;
302 }
303 case GCCause::_metadata_GC_clear_soft_refs: {
304 HandleMark hm(thread);
305 do_full_collection(true); // do clear all soft refs
306 break;
307 }
308 default:
309 ShouldNotReachHere(); // Unexpected use of this function
310 }
311 }
312
313 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
314 size_t word_size,
315 Metaspace::MetadataType mdtype) {
316 uint loop_count = 0;
317 uint gc_count = 0;
318 uint full_gc_count = 0;
319
320 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
321
322 do {
323 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
324 if (result != nullptr) {
325 return result;
326 }
327
328 if (GCLocker::is_active_and_needs_gc()) {
329 // If the GCLocker is active, just expand and allocate.
330 // If that does not succeed, wait if this thread is not
331 // in a critical section itself.
332 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
333 if (result != nullptr) {
334 return result;
335 }
336 JavaThread* jthr = JavaThread::current();
337 if (!jthr->in_critical()) {
338 // Wait for JNI critical section to be exited
339 GCLocker::stall_until_clear();
340 // The GC invoked by the last thread leaving the critical
341 // section will be a young collection and a full collection
342 // is (currently) needed for unloading classes so continue
343 // to the next iteration to get a full GC.
344 continue;
345 } else {
346 if (CheckJNICalls) {
347 fatal("Possible deadlock due to allocating while"
348 " in jni critical section");
349 }
350 return nullptr;
351 }
352 }
353
354 { // Need lock to get self consistent gc_count's
355 MutexLocker ml(Heap_lock);
356 gc_count = Universe::heap()->total_collections();
357 full_gc_count = Universe::heap()->total_full_collections();
358 }
359
360 // Generate a VM operation
361 VM_CollectForMetadataAllocation op(loader_data,
362 word_size,
363 mdtype,
364 gc_count,
365 full_gc_count,
366 GCCause::_metadata_GC_threshold);
367 VMThread::execute(&op);
368
369 // If GC was locked out, try again. Check before checking success because the
370 // prologue could have succeeded and the GC still have been locked out.
371 if (op.gc_locked()) {
372 continue;
373 }
374
375 if (op.prologue_succeeded()) {
376 return op.result();
377 }
378 loop_count++;
379 if ((QueuedAllocationWarningCount > 0) &&
380 (loop_count % QueuedAllocationWarningCount == 0)) {
381 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
382 " size=" SIZE_FORMAT, loop_count, word_size);
383 }
384 } while (true); // Until a GC is done
385 }
386
387 MemoryUsage CollectedHeap::memory_usage() {
388 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity());
389 }
390
391 void CollectedHeap::set_gc_cause(GCCause::Cause v) {
392 if (UsePerfData) {
393 _gc_lastcause = _gc_cause;
394 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause));
395 _perf_gc_cause->set_value(GCCause::to_string(v));
396 }
397 _gc_cause = v;
398 }
399
400 #ifndef PRODUCT
401 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
402 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
403 // please note mismatch between size (in 32/64 bit words), and ju_addr that always point to a 32 bit word
404 for (juint* ju_addr = reinterpret_cast<juint*>(addr); ju_addr < reinterpret_cast<juint*>(addr + size); ++ju_addr) {
405 assert(*ju_addr == badHeapWordVal, "Found non badHeapWordValue in pre-allocation check");
406 }
407 }
408 }
409 #endif // PRODUCT
410
411 size_t CollectedHeap::max_tlab_size() const {
412 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
413 // This restriction could be removed by enabling filling with multiple arrays.
414 // If we compute that the reasonable way as
415 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
416 // we'll overflow on the multiply, so we do the divide first.
417 // We actually lose a little by dividing first,
418 // but that just makes the TLAB somewhat smaller than the biggest array,
419 // which is fine, since we'll be able to fill that.
420 int header_size_in_bytes = typeArrayOopDesc::base_offset_in_bytes(T_INT);
421 assert(header_size_in_bytes % sizeof(jint) == 0, "header size must align to int");
422 size_t max_int_size = header_size_in_bytes / HeapWordSize +
423 sizeof(jint) *
424 ((juint) max_jint / (size_t) HeapWordSize);
425 return align_down(max_int_size, MinObjAlignment);
426 }
427
428 size_t CollectedHeap::filler_array_min_size() {
429 int aligned_header_size_words = align_up(arrayOopDesc::base_offset_in_bytes(T_INT), HeapWordSize) / HeapWordSize;
430 return align_object_size(aligned_header_size_words); // align to MinObjAlignment
431 }
432
433 void CollectedHeap::zap_filler_array_with(HeapWord* start, size_t words, juint value) {
434 int payload_start = align_up(arrayOopDesc::base_offset_in_bytes(T_INT), HeapWordSize) / HeapWordSize;
435 Copy::fill_to_words(start + payload_start,
436 words - payload_start, value);
437 }
438
439 #ifdef ASSERT
440 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
441 {
442 assert(words >= min_fill_size(), "too small to fill");
443 assert(is_object_aligned(words), "unaligned size");
444 }
445
446 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
447 {
448 if (ZapFillerObjects && zap) {
449 zap_filler_array_with(start, words, 0XDEAFBABE);
450 }
451 }
452 #endif // ASSERT
453
454 void
455 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
456 {
457 assert(words >= filler_array_min_size(), "too small for an array");
458 assert(words <= filler_array_max_size(), "too big for a single object");
459
460 const size_t payload_size_bytes = words * HeapWordSize - arrayOopDesc::base_offset_in_bytes(T_INT);
461 assert(payload_size_bytes % sizeof(jint) == 0, "must be int aligned");
462 const size_t len = payload_size_bytes / sizeof(jint);
463 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
464
465 ObjArrayAllocator allocator(Universe::fillerArrayKlassObj(), words, (int)len, /* do_zero */ false);
466 allocator.initialize(start);
467 if (DumpSharedSpaces) {
468 // This array is written into the CDS archive. Make sure it
469 // has deterministic contents.
470 zap_filler_array_with(start, words, 0);
471 } else {
472 DEBUG_ONLY(zap_filler_array(start, words, zap);)
473 }
474 }
475
476 void
477 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
478 {
479 assert(words <= filler_array_max_size(), "too big for a single object");
480
481 if (words >= filler_array_min_size()) {
482 fill_with_array(start, words, zap);
483 } else if (words > 0) {
484 assert(words == min_fill_size(), "unaligned size");
485 ObjAllocator allocator(CollectedHeap::filler_object_klass(), words);
486 allocator.initialize(start);
487 }
488 }
489
490 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
491 {
492 DEBUG_ONLY(fill_args_check(start, words);)
493 HandleMark hm(Thread::current()); // Free handles before leaving.
494 fill_with_object_impl(start, words, zap);
495 }
496
497 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
498 {
499 DEBUG_ONLY(fill_args_check(start, words);)
500 HandleMark hm(Thread::current()); // Free handles before leaving.
501
502 // Multiple objects may be required depending on the filler array maximum size. Fill
503 // the range up to that with objects that are filler_array_max_size sized. The
504 // remainder is filled with a single object.
505 const size_t min = min_fill_size();
506 const size_t max = filler_array_max_size();
507 while (words > max) {
508 const size_t cur = (words - max) >= min ? max : max - min;
509 fill_with_array(start, cur, zap);
510 start += cur;
511 words -= cur;
512 }
513
514 fill_with_object_impl(start, words, zap);
515 }
516
517 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
518 CollectedHeap::fill_with_object(start, end, zap);
519 }
520
521 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
522 size_t requested_size,
523 size_t* actual_size) {
524 guarantee(false, "thread-local allocation buffers not supported");
525 return nullptr;
526 }
527
528 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
529 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
530 "Should only be called at a safepoint or at start-up");
531
532 ThreadLocalAllocStats stats;
533
534 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) {
535 BarrierSet::barrier_set()->make_parsable(thread);
536 if (UseTLAB) {
537 if (retire_tlabs) {
538 thread->tlab().retire(&stats);
539 } else {
540 thread->tlab().make_parsable();
541 }
542 }
543 }
544
545 stats.publish();
546 }
547
548 void CollectedHeap::resize_all_tlabs() {
549 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
550 "Should only resize tlabs at safepoint");
551
552 if (UseTLAB && ResizeTLAB) {
553 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
554 thread->tlab().resize();
555 }
556 }
557 }
558
559 jlong CollectedHeap::millis_since_last_whole_heap_examined() {
560 return (os::javaTimeNanos() - _last_whole_heap_examined_time_ns) / NANOSECS_PER_MILLISEC;
561 }
562
563 void CollectedHeap::record_whole_heap_examined_timestamp() {
564 _last_whole_heap_examined_time_ns = os::javaTimeNanos();
565 }
566
567 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
568 assert(timer != nullptr, "timer is null");
569 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
570 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
571 HeapDumper::dump_heap();
572 }
573
574 LogTarget(Trace, gc, classhisto) lt;
575 if (lt.is_enabled()) {
576 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
577 ResourceMark rm;
578 LogStream ls(lt);
579 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
580 inspector.doit();
581 }
582 }
583
584 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
585 full_gc_dump(timer, true);
586 }
587
588 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
589 full_gc_dump(timer, false);
590 }
591
592 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) {
593 // It is important to do this in a way such that concurrent readers can't
594 // temporarily think something is in the heap. (Seen this happen in asserts.)
595 _reserved.set_word_size(0);
596 _reserved.set_start((HeapWord*)rs.base());
597 _reserved.set_end((HeapWord*)rs.end());
598 }
599
600 void CollectedHeap::post_initialize() {
601 StringDedup::initialize();
602 initialize_serviceability();
603 }
604
605 #ifndef PRODUCT
606
607 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
608 // Access to count is not atomic; the value does not have to be exact.
609 if (PromotionFailureALot) {
610 const size_t gc_num = total_collections();
611 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
612 if (elapsed_gcs >= PromotionFailureALotInterval) {
613 // Test for unsigned arithmetic wrap-around.
614 if (++*count >= PromotionFailureALotCount) {
615 *count = 0;
616 return true;
617 }
618 }
619 }
620 return false;
621 }
622
623 bool CollectedHeap::promotion_should_fail() {
624 return promotion_should_fail(&_promotion_failure_alot_count);
625 }
626
627 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
628 if (PromotionFailureALot) {
629 _promotion_failure_alot_gc_number = total_collections();
630 *count = 0;
631 }
632 }
633
634 void CollectedHeap::reset_promotion_should_fail() {
635 reset_promotion_should_fail(&_promotion_failure_alot_count);
636 }
637
638 #endif // #ifndef PRODUCT
639
640 // It's the caller's responsibility to ensure glitch-freedom
641 // (if required).
642 void CollectedHeap::update_capacity_and_used_at_gc() {
643 _capacity_at_last_gc = capacity();
644 _used_at_last_gc = used();
645 }