1 /*
2 * Copyright (c) 2001, 2018, 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/systemDictionary.hpp"
27 #include "gc/shared/allocTracer.hpp"
28 #include "gc/shared/barrierSet.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "gc/shared/gcLocker.inline.hpp"
32 #include "gc/shared/gcHeapSummary.hpp"
33 #include "gc/shared/gcTrace.hpp"
34 #include "gc/shared/gcTraceTime.inline.hpp"
35 #include "gc/shared/gcWhen.hpp"
36 #include "gc/shared/vmGCOperations.hpp"
37 #include "logging/log.hpp"
38 #include "memory/metaspace.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "oops/instanceMirrorKlass.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "runtime/handles.inline.hpp"
43 #include "runtime/init.hpp"
44 #include "runtime/thread.inline.hpp"
45 #include "runtime/threadSMR.hpp"
46 #include "runtime/vmThread.hpp"
47 #include "services/heapDumper.hpp"
48 #include "utilities/align.hpp"
49
50 class ClassLoaderData;
51
52 #ifdef ASSERT
53 int CollectedHeap::_fire_out_of_memory_count = 0;
54 #endif
55
56 size_t CollectedHeap::_filler_array_max_size = 0;
57
58 template <>
59 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
60 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
61 st->print_raw(m);
62 }
63
64 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
65 if (!should_log()) {
66 return;
67 }
68
69 double timestamp = fetch_timestamp();
70 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
71 int index = compute_log_index();
72 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
73 _records[index].timestamp = timestamp;
74 _records[index].data.is_before = before;
75 stringStream st(_records[index].data.buffer(), _records[index].data.size());
76
77 st.print_cr("{Heap %s GC invocations=%u (full %u):",
78 before ? "before" : "after",
79 heap->total_collections(),
80 heap->total_full_collections());
81
82 heap->print_on(&st);
83 st.print_cr("}");
84 }
85
86 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
87 size_t capacity_in_words = capacity() / HeapWordSize;
88
89 return VirtualSpaceSummary(
90 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
91 }
92
93 GCHeapSummary CollectedHeap::create_heap_summary() {
94 VirtualSpaceSummary heap_space = create_heap_space_summary();
95 return GCHeapSummary(heap_space, used());
96 }
97
98 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
99 const MetaspaceSizes meta_space(
100 MetaspaceUtils::committed_bytes(),
101 MetaspaceUtils::used_bytes(),
102 MetaspaceUtils::reserved_bytes());
103 const MetaspaceSizes data_space(
104 MetaspaceUtils::committed_bytes(Metaspace::NonClassType),
105 MetaspaceUtils::used_bytes(Metaspace::NonClassType),
106 MetaspaceUtils::reserved_bytes(Metaspace::NonClassType));
107 const MetaspaceSizes class_space(
108 MetaspaceUtils::committed_bytes(Metaspace::ClassType),
109 MetaspaceUtils::used_bytes(Metaspace::ClassType),
110 MetaspaceUtils::reserved_bytes(Metaspace::ClassType));
111
112 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
113 MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType);
114 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
115 MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType);
116
117 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
118 ms_chunk_free_list_summary, class_chunk_free_list_summary);
119 }
120
121 void CollectedHeap::print_heap_before_gc() {
122 Universe::print_heap_before_gc();
123 if (_gc_heap_log != NULL) {
124 _gc_heap_log->log_heap_before(this);
125 }
126 }
127
128 void CollectedHeap::print_heap_after_gc() {
129 Universe::print_heap_after_gc();
130 if (_gc_heap_log != NULL) {
131 _gc_heap_log->log_heap_after(this);
132 }
133 }
134
135 void CollectedHeap::print_on_error(outputStream* st) const {
136 st->print_cr("Heap:");
137 print_extended_on(st);
138 st->cr();
139
140 BarrierSet::barrier_set()->print_on(st);
141 }
142
143 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
144 const GCHeapSummary& heap_summary = create_heap_summary();
145 gc_tracer->report_gc_heap_summary(when, heap_summary);
146
147 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
148 gc_tracer->report_metaspace_summary(when, metaspace_summary);
149 }
150
151 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
152 trace_heap(GCWhen::BeforeGC, gc_tracer);
153 }
154
155 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
156 trace_heap(GCWhen::AfterGC, gc_tracer);
157 }
158
159 // WhiteBox API support for concurrent collectors. These are the
160 // default implementations, for collectors which don't support this
161 // feature.
162 bool CollectedHeap::supports_concurrent_phase_control() const {
163 return false;
164 }
165
166 const char* const* CollectedHeap::concurrent_phases() const {
167 static const char* const result[] = { NULL };
168 return result;
169 }
170
171 bool CollectedHeap::request_concurrent_phase(const char* phase) {
172 return false;
173 }
174
175 bool CollectedHeap::is_oop(oop object) const {
176 if (!check_obj_alignment(object)) {
177 return false;
178 }
179
180 if (!is_in_reserved(object)) {
181 return false;
182 }
183
184 if (is_in_reserved(object->klass_or_null())) {
185 return false;
186 }
187
188 return true;
189 }
190
191 // Memory state functions.
192
193
194 CollectedHeap::CollectedHeap() :
195 _is_gc_active(false),
196 _total_collections(0),
197 _total_full_collections(0),
198 _gc_cause(GCCause::_no_gc),
199 _gc_lastcause(GCCause::_no_gc)
200 {
201 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
202 const size_t elements_per_word = HeapWordSize / sizeof(jint);
203 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
204 max_len / elements_per_word);
205
206 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
207 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
208
209 if (UsePerfData) {
210 EXCEPTION_MARK;
211
212 // create the gc cause jvmstat counters
213 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
214 80, GCCause::to_string(_gc_cause), CHECK);
215
216 _perf_gc_lastcause =
217 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
218 80, GCCause::to_string(_gc_lastcause), CHECK);
219 }
220
221 // Create the ring log
222 if (LogEvents) {
223 _gc_heap_log = new GCHeapLog();
224 } else {
225 _gc_heap_log = NULL;
226 }
227 }
228
229 // This interface assumes that it's being called by the
230 // vm thread. It collects the heap assuming that the
231 // heap lock is already held and that we are executing in
232 // the context of the vm thread.
233 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
234 assert(Thread::current()->is_VM_thread(), "Precondition#1");
235 assert(Heap_lock->is_locked(), "Precondition#2");
236 GCCauseSetter gcs(this, cause);
237 switch (cause) {
238 case GCCause::_heap_inspection:
239 case GCCause::_heap_dump:
240 case GCCause::_metadata_GC_threshold : {
241 HandleMark hm;
242 do_full_collection(false); // don't clear all soft refs
243 break;
244 }
245 case GCCause::_metadata_GC_clear_soft_refs: {
246 HandleMark hm;
247 do_full_collection(true); // do clear all soft refs
248 break;
249 }
250 default:
251 ShouldNotReachHere(); // Unexpected use of this function
252 }
253 }
254
255 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
256 size_t word_size,
257 Metaspace::MetadataType mdtype) {
258 uint loop_count = 0;
259 uint gc_count = 0;
260 uint full_gc_count = 0;
261
262 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
263
264 do {
265 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
266 if (result != NULL) {
267 return result;
268 }
269
270 if (GCLocker::is_active_and_needs_gc()) {
271 // If the GCLocker is active, just expand and allocate.
272 // If that does not succeed, wait if this thread is not
273 // in a critical section itself.
274 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
275 if (result != NULL) {
276 return result;
277 }
278 JavaThread* jthr = JavaThread::current();
279 if (!jthr->in_critical()) {
280 // Wait for JNI critical section to be exited
281 GCLocker::stall_until_clear();
282 // The GC invoked by the last thread leaving the critical
283 // section will be a young collection and a full collection
284 // is (currently) needed for unloading classes so continue
285 // to the next iteration to get a full GC.
286 continue;
287 } else {
288 if (CheckJNICalls) {
289 fatal("Possible deadlock due to allocating while"
290 " in jni critical section");
291 }
292 return NULL;
293 }
294 }
295
296 { // Need lock to get self consistent gc_count's
297 MutexLocker ml(Heap_lock);
298 gc_count = Universe::heap()->total_collections();
299 full_gc_count = Universe::heap()->total_full_collections();
300 }
301
302 // Generate a VM operation
303 VM_CollectForMetadataAllocation op(loader_data,
304 word_size,
305 mdtype,
306 gc_count,
307 full_gc_count,
308 GCCause::_metadata_GC_threshold);
309 VMThread::execute(&op);
310
311 // If GC was locked out, try again. Check before checking success because the
312 // prologue could have succeeded and the GC still have been locked out.
313 if (op.gc_locked()) {
314 continue;
315 }
316
317 if (op.prologue_succeeded()) {
318 return op.result();
319 }
320 loop_count++;
321 if ((QueuedAllocationWarningCount > 0) &&
322 (loop_count % QueuedAllocationWarningCount == 0)) {
323 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
324 " size=" SIZE_FORMAT, loop_count, word_size);
325 }
326 } while (true); // Until a GC is done
327 }
328
329 #ifndef PRODUCT
330 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
331 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
332 for (size_t slot = 0; slot < size; slot += 1) {
333 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
334 "Found badHeapWordValue in post-allocation check");
335 }
336 }
337 }
338
339 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
340 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
341 for (size_t slot = 0; slot < size; slot += 1) {
342 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
343 "Found non badHeapWordValue in pre-allocation check");
344 }
345 }
346 }
347 #endif // PRODUCT
348
349 #ifdef ASSERT
350 void CollectedHeap::check_for_valid_allocation_state() {
351 Thread *thread = Thread::current();
352 // How to choose between a pending exception and a potential
353 // OutOfMemoryError? Don't allow pending exceptions.
354 // This is a VM policy failure, so how do we exhaustively test it?
355 assert(!thread->has_pending_exception(),
356 "shouldn't be allocating with pending exception");
357 if (StrictSafepointChecks) {
358 assert(thread->allow_allocation(),
359 "Allocation done by thread for which allocation is blocked "
360 "by No_Allocation_Verifier!");
361 // Allocation of an oop can always invoke a safepoint,
362 // hence, the true argument
363 thread->check_for_valid_safepoint_state(true);
364 }
365 }
366 #endif
367
368 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
369
370 // Retain tlab and allocate object in shared space if
371 // the amount free in the tlab is too large to discard.
372 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
373 thread->tlab().record_slow_allocation(size);
374 return NULL;
375 }
376
377 // Discard tlab and allocate a new one.
378 // To minimize fragmentation, the last TLAB may be smaller than the rest.
379 size_t new_tlab_size = thread->tlab().compute_size(size);
380
381 thread->tlab().clear_before_allocation();
382
383 if (new_tlab_size == 0) {
384 return NULL;
385 }
386
387 // Allocate a new TLAB requesting new_tlab_size. Any size
388 // between minimal and new_tlab_size is accepted.
389 size_t actual_tlab_size = 0;
390 size_t min_tlab_size = ThreadLocalAllocBuffer::compute_min_size(size);
391 HeapWord* obj = Universe::heap()->allocate_new_tlab(min_tlab_size, new_tlab_size, &actual_tlab_size);
392 if (obj == NULL) {
393 assert(actual_tlab_size == 0, "Allocation failed, but actual size was updated. min: " SIZE_FORMAT ", desired: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
394 min_tlab_size, new_tlab_size, actual_tlab_size);
395 return NULL;
396 }
397 assert(actual_tlab_size != 0, "Allocation succeeded but actual size not updated. obj at: " PTR_FORMAT " min: " SIZE_FORMAT ", desired: " SIZE_FORMAT,
398 p2i(obj), min_tlab_size, new_tlab_size);
399
400 AllocTracer::send_allocation_in_new_tlab(klass, obj, actual_tlab_size * HeapWordSize, size * HeapWordSize, thread);
401
402 if (ZeroTLAB) {
403 // ..and clear it.
404 Copy::zero_to_words(obj, actual_tlab_size);
405 } else {
406 // ...and zap just allocated object.
407 #ifdef ASSERT
408 // Skip mangling the space corresponding to the object header to
409 // ensure that the returned space is not considered parsable by
410 // any concurrent GC thread.
411 size_t hdr_size = oopDesc::header_size();
412 Copy::fill_to_words(obj + hdr_size, actual_tlab_size - hdr_size, badHeapWordVal);
413 #endif // ASSERT
414 }
415 thread->tlab().fill(obj, obj + size, actual_tlab_size);
416 return obj;
417 }
418
419 size_t CollectedHeap::max_tlab_size() const {
420 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
421 // This restriction could be removed by enabling filling with multiple arrays.
422 // If we compute that the reasonable way as
423 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
424 // we'll overflow on the multiply, so we do the divide first.
425 // We actually lose a little by dividing first,
426 // but that just makes the TLAB somewhat smaller than the biggest array,
427 // which is fine, since we'll be able to fill that.
428 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
429 sizeof(jint) *
430 ((juint) max_jint / (size_t) HeapWordSize);
431 return align_down(max_int_size, MinObjAlignment);
432 }
433
434 size_t CollectedHeap::filler_array_hdr_size() {
435 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
436 }
437
438 size_t CollectedHeap::filler_array_min_size() {
439 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
440 }
441
442 #ifdef ASSERT
443 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
444 {
445 assert(words >= min_fill_size(), "too small to fill");
446 assert(is_object_aligned(words), "unaligned size");
447 assert(Universe::heap()->is_in_reserved(start), "not in heap");
448 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
449 }
450
451 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
452 {
453 if (ZapFillerObjects && zap) {
454 Copy::fill_to_words(start + filler_array_hdr_size(),
455 words - filler_array_hdr_size(), 0XDEAFBABE);
456 }
457 }
458 #endif // ASSERT
459
460 void
461 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
462 {
463 assert(words >= filler_array_min_size(), "too small for an array");
464 assert(words <= filler_array_max_size(), "too big for a single object");
465
466 const size_t payload_size = words - filler_array_hdr_size();
467 const size_t len = payload_size * HeapWordSize / sizeof(jint);
468 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
469
470 // Set the length first for concurrent GC.
471 ((arrayOop)start)->set_length((int)len);
472 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
473 DEBUG_ONLY(zap_filler_array(start, words, zap);)
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 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
486 }
487 }
488
489 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
490 {
491 DEBUG_ONLY(fill_args_check(start, words);)
492 HandleMark hm; // Free handles before leaving.
493 fill_with_object_impl(start, words, zap);
494 }
495
496 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
497 {
498 DEBUG_ONLY(fill_args_check(start, words);)
499 HandleMark hm; // Free handles before leaving.
500
501 // Multiple objects may be required depending on the filler array maximum size. Fill
502 // the range up to that with objects that are filler_array_max_size sized. The
503 // remainder is filled with a single object.
504 const size_t min = min_fill_size();
505 const size_t max = filler_array_max_size();
506 while (words > max) {
507 const size_t cur = (words - max) >= min ? max : max - min;
508 fill_with_array(start, cur, zap);
509 start += cur;
510 words -= cur;
511 }
512
513 fill_with_object_impl(start, words, zap);
514 }
515
516 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
517 size_t requested_size,
518 size_t* actual_size) {
519 guarantee(false, "thread-local allocation buffers not supported");
520 return NULL;
521 }
522
523 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
524 // The second disjunct in the assertion below makes a concession
525 // for the start-up verification done while the VM is being
526 // created. Callers be careful that you know that mutators
527 // aren't going to interfere -- for instance, this is permissible
528 // if we are still single-threaded and have either not yet
529 // started allocating (nothing much to verify) or we have
530 // started allocating but are now a full-fledged JavaThread
531 // (and have thus made our TLAB's) available for filling.
532 assert(SafepointSynchronize::is_at_safepoint() ||
533 !is_init_completed(),
534 "Should only be called at a safepoint or at start-up"
535 " otherwise concurrent mutator activity may make heap "
536 " unparsable again");
537 const bool use_tlab = UseTLAB;
538 // The main thread starts allocating via a TLAB even before it
539 // has added itself to the threads list at vm boot-up.
540 JavaThreadIteratorWithHandle jtiwh;
541 assert(!use_tlab || jtiwh.length() > 0,
542 "Attempt to fill tlabs before main thread has been added"
543 " to threads list is doomed to failure!");
544 BarrierSet *bs = BarrierSet::barrier_set();
545 for (; JavaThread *thread = jtiwh.next(); ) {
546 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
547 bs->make_parsable(thread);
548 }
549 }
550
551 void CollectedHeap::accumulate_statistics_all_tlabs() {
552 if (UseTLAB) {
553 assert(SafepointSynchronize::is_at_safepoint() ||
554 !is_init_completed(),
555 "should only accumulate statistics on tlabs at safepoint");
556
557 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
558 }
559 }
560
561 void CollectedHeap::resize_all_tlabs() {
562 if (UseTLAB) {
563 assert(SafepointSynchronize::is_at_safepoint() ||
564 !is_init_completed(),
565 "should only resize tlabs at safepoint");
566
567 ThreadLocalAllocBuffer::resize_all_tlabs();
568 }
569 }
570
571 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
572 assert(timer != NULL, "timer is null");
573 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
574 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
575 HeapDumper::dump_heap();
576 }
577
578 LogTarget(Trace, gc, classhisto) lt;
579 if (lt.is_enabled()) {
580 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
581 ResourceMark rm;
582 LogStream ls(lt);
583 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
584 inspector.doit();
585 }
586 }
587
588 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
589 full_gc_dump(timer, true);
590 }
591
592 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
593 full_gc_dump(timer, false);
594 }
595
596 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
597 // It is important to do this in a way such that concurrent readers can't
598 // temporarily think something is in the heap. (Seen this happen in asserts.)
599 _reserved.set_word_size(0);
600 _reserved.set_start(start);
601 _reserved.set_end(end);
602 }
603
604 void CollectedHeap::post_initialize() {
605 initialize_serviceability();
606 }
607
608 #ifndef PRODUCT
609
610 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
611 // Access to count is not atomic; the value does not have to be exact.
612 if (PromotionFailureALot) {
613 const size_t gc_num = total_collections();
614 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
615 if (elapsed_gcs >= PromotionFailureALotInterval) {
616 // Test for unsigned arithmetic wrap-around.
617 if (++*count >= PromotionFailureALotCount) {
618 *count = 0;
619 return true;
620 }
621 }
622 }
623 return false;
624 }
625
626 bool CollectedHeap::promotion_should_fail() {
627 return promotion_should_fail(&_promotion_failure_alot_count);
628 }
629
630 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
631 if (PromotionFailureALot) {
632 _promotion_failure_alot_gc_number = total_collections();
633 *count = 0;
634 }
635 }
636
637 void CollectedHeap::reset_promotion_should_fail() {
638 reset_promotion_should_fail(&_promotion_failure_alot_count);
639 }
640
641 #endif // #ifndef PRODUCT
642
643 bool CollectedHeap::supports_object_pinning() const {
644 return false;
645 }
646
647 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
648 ShouldNotReachHere();
649 return NULL;
650 }
651
652 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
653 ShouldNotReachHere();
654 }