1 /*
2 * Copyright (c) 2001, 2022, 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_t)0;
64 Klass* CollectedHeap::_filler_object_klass = NULL;
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 = NULL; // 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 void CollectedHeap::print_heap_before_gc() {
156 LogTarget(Debug, gc, heap) lt;
157 if (lt.is_enabled()) {
158 LogStream ls(lt);
159 ls.print_cr("Heap before GC invocations=%u (full %u):", total_collections(), total_full_collections());
160 ResourceMark rm;
161 print_on(&ls);
162 }
163
164 if (_gc_heap_log != NULL) {
165 _gc_heap_log->log_heap_before(this);
166 }
167 }
168
169 void CollectedHeap::print_heap_after_gc() {
170 LogTarget(Debug, gc, heap) lt;
171 if (lt.is_enabled()) {
172 LogStream ls(lt);
173 ls.print_cr("Heap after GC invocations=%u (full %u):", total_collections(), total_full_collections());
174 ResourceMark rm;
175 print_on(&ls);
176 }
177
178 if (_gc_heap_log != NULL) {
179 _gc_heap_log->log_heap_after(this);
180 }
181 }
182
183 void CollectedHeap::print() const { print_on(tty); }
184
185 void CollectedHeap::print_on_error(outputStream* st) const {
186 st->print_cr("Heap:");
187 print_extended_on(st);
188 st->cr();
189
190 BarrierSet* bs = BarrierSet::barrier_set();
191 if (bs != NULL) {
192 bs->print_on(st);
193 }
194 }
195
196 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
197 const GCHeapSummary& heap_summary = create_heap_summary();
198 gc_tracer->report_gc_heap_summary(when, heap_summary);
199
200 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
201 gc_tracer->report_metaspace_summary(when, metaspace_summary);
202 }
203
204 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
205 trace_heap(GCWhen::BeforeGC, gc_tracer);
206 }
207
208 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
209 trace_heap(GCWhen::AfterGC, gc_tracer);
210 }
211
212 // Default implementation, for collectors that don't support the feature.
213 bool CollectedHeap::supports_concurrent_gc_breakpoints() const {
214 return false;
215 }
216
217 bool CollectedHeap::is_oop(oop object) const {
218 if (!is_object_aligned(object)) {
219 return false;
220 }
221
222 if (!is_in(object)) {
223 return false;
224 }
225
226 if (is_in(object->klass_or_null())) {
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 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
257 max_len / elements_per_word);
258
259 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
260 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
261
262 if (UsePerfData) {
263 EXCEPTION_MARK;
264
265 // create the gc cause jvmstat counters
266 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
267 80, GCCause::to_string(_gc_cause), CHECK);
268
269 _perf_gc_lastcause =
270 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
271 80, GCCause::to_string(_gc_lastcause), CHECK);
272 }
273
274 // Create the ring log
275 if (LogEvents) {
276 _gc_heap_log = new GCHeapLog();
277 } else {
278 _gc_heap_log = NULL;
279 }
280 }
281
282 // This interface assumes that it's being called by the
283 // vm thread. It collects the heap assuming that the
284 // heap lock is already held and that we are executing in
285 // the context of the vm thread.
286 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
287 Thread* thread = Thread::current();
288 assert(thread->is_VM_thread(), "Precondition#1");
289 assert(Heap_lock->is_locked(), "Precondition#2");
290 GCCauseSetter gcs(this, cause);
291 switch (cause) {
292 case GCCause::_codecache_GC_threshold:
293 case GCCause::_codecache_GC_aggressive:
294 case GCCause::_heap_inspection:
295 case GCCause::_heap_dump:
296 case GCCause::_metadata_GC_threshold: {
297 HandleMark hm(thread);
298 do_full_collection(false); // don't clear all soft refs
299 break;
300 }
301 case GCCause::_archive_time_gc:
302 case GCCause::_metadata_GC_clear_soft_refs: {
303 HandleMark hm(thread);
304 do_full_collection(true); // do clear all soft refs
305 break;
306 }
307 default:
308 ShouldNotReachHere(); // Unexpected use of this function
309 }
310 }
311
312 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
313 size_t word_size,
314 Metaspace::MetadataType mdtype) {
315 uint loop_count = 0;
316 uint gc_count = 0;
317 uint full_gc_count = 0;
318
319 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
320
321 do {
322 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
323 if (result != NULL) {
324 return result;
325 }
326
327 if (GCLocker::is_active_and_needs_gc()) {
328 // If the GCLocker is active, just expand and allocate.
329 // If that does not succeed, wait if this thread is not
330 // in a critical section itself.
331 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
332 if (result != NULL) {
333 return result;
334 }
335 JavaThread* jthr = JavaThread::current();
336 if (!jthr->in_critical()) {
337 // Wait for JNI critical section to be exited
338 GCLocker::stall_until_clear();
339 // The GC invoked by the last thread leaving the critical
340 // section will be a young collection and a full collection
341 // is (currently) needed for unloading classes so continue
342 // to the next iteration to get a full GC.
343 continue;
344 } else {
345 if (CheckJNICalls) {
346 fatal("Possible deadlock due to allocating while"
347 " in jni critical section");
348 }
349 return NULL;
350 }
351 }
352
353 { // Need lock to get self consistent gc_count's
354 MutexLocker ml(Heap_lock);
355 gc_count = Universe::heap()->total_collections();
356 full_gc_count = Universe::heap()->total_full_collections();
357 }
358
359 // Generate a VM operation
360 VM_CollectForMetadataAllocation op(loader_data,
361 word_size,
362 mdtype,
363 gc_count,
364 full_gc_count,
365 GCCause::_metadata_GC_threshold);
366 VMThread::execute(&op);
367
368 // If GC was locked out, try again. Check before checking success because the
369 // prologue could have succeeded and the GC still have been locked out.
370 if (op.gc_locked()) {
371 continue;
372 }
373
374 if (op.prologue_succeeded()) {
375 return op.result();
376 }
377 loop_count++;
378 if ((QueuedAllocationWarningCount > 0) &&
379 (loop_count % QueuedAllocationWarningCount == 0)) {
380 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
381 " size=" SIZE_FORMAT, loop_count, word_size);
382 }
383 } while (true); // Until a GC is done
384 }
385
386 MemoryUsage CollectedHeap::memory_usage() {
387 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity());
388 }
389
390 void CollectedHeap::set_gc_cause(GCCause::Cause v) {
391 if (UsePerfData) {
392 _gc_lastcause = _gc_cause;
393 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause));
394 _perf_gc_cause->set_value(GCCause::to_string(v));
395 }
396 _gc_cause = v;
397 }
398
399 #ifndef PRODUCT
400 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
401 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
402 // please note mismatch between size (in 32/64 bit words), and ju_addr that always point to a 32 bit word
403 for (juint* ju_addr = reinterpret_cast<juint*>(addr); ju_addr < reinterpret_cast<juint*>(addr + size); ++ju_addr) {
404 assert(*ju_addr == badHeapWordVal, "Found non badHeapWordValue in pre-allocation check");
405 }
406 }
407 }
408 #endif // PRODUCT
409
410 size_t CollectedHeap::max_tlab_size() const {
411 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
412 // This restriction could be removed by enabling filling with multiple arrays.
413 // If we compute that the reasonable way as
414 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
415 // we'll overflow on the multiply, so we do the divide first.
416 // We actually lose a little by dividing first,
417 // but that just makes the TLAB somewhat smaller than the biggest array,
418 // which is fine, since we'll be able to fill that.
419 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
420 sizeof(jint) *
421 ((juint) max_jint / (size_t) HeapWordSize);
422 return align_down(max_int_size, MinObjAlignment);
423 }
424
425 size_t CollectedHeap::filler_array_hdr_size() {
426 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
427 }
428
429 size_t CollectedHeap::filler_array_min_size() {
430 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
431 }
432
433 void CollectedHeap::zap_filler_array_with(HeapWord* start, size_t words, juint value) {
434 Copy::fill_to_words(start + filler_array_hdr_size(),
435 words - filler_array_hdr_size(), value);
436 }
437
438 #ifdef ASSERT
439 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
440 {
441 assert(words >= min_fill_size(), "too small to fill");
442 assert(is_object_aligned(words), "unaligned size");
443 }
444
445 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
446 {
447 if (ZapFillerObjects && zap) {
448 zap_filler_array_with(start, words, 0XDEAFBABE);
449 }
450 }
451 #endif // ASSERT
452
453 void
454 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
455 {
456 assert(words >= filler_array_min_size(), "too small for an array");
457 assert(words <= filler_array_max_size(), "too big for a single object");
458
459 const size_t payload_size = words - filler_array_hdr_size();
460 const size_t len = payload_size * HeapWordSize / sizeof(jint);
461 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
462
463 ObjArrayAllocator allocator(Universe::fillerArrayKlassObj(), words, (int)len, /* do_zero */ false);
464 allocator.initialize(start);
465 if (DumpSharedSpaces) {
466 // This array is written into the CDS archive. Make sure it
467 // has deterministic contents.
468 zap_filler_array_with(start, words, 0);
469 } else {
470 DEBUG_ONLY(zap_filler_array(start, words, zap);)
471 }
472 }
473
474 void
475 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
476 {
477 assert(words <= filler_array_max_size(), "too big for a single object");
478
479 if (words >= filler_array_min_size()) {
480 fill_with_array(start, words, zap);
481 } else if (words > 0) {
482 assert(words == min_fill_size(), "unaligned size");
483 ObjAllocator allocator(CollectedHeap::filler_object_klass(), words);
484 allocator.initialize(start);
485 }
486 }
487
488 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
489 {
490 DEBUG_ONLY(fill_args_check(start, words);)
491 HandleMark hm(Thread::current()); // Free handles before leaving.
492 fill_with_object_impl(start, words, zap);
493 }
494
495 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
496 {
497 DEBUG_ONLY(fill_args_check(start, words);)
498 HandleMark hm(Thread::current()); // Free handles before leaving.
499
500 // Multiple objects may be required depending on the filler array maximum size. Fill
501 // the range up to that with objects that are filler_array_max_size sized. The
502 // remainder is filled with a single object.
503 const size_t min = min_fill_size();
504 const size_t max = filler_array_max_size();
505 while (words > max) {
506 const size_t cur = (words - max) >= min ? max : max - min;
507 fill_with_array(start, cur, zap);
508 start += cur;
509 words -= cur;
510 }
511
512 fill_with_object_impl(start, words, zap);
513 }
514
515 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
516 CollectedHeap::fill_with_object(start, end, zap);
517 }
518
519 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
520 size_t requested_size,
521 size_t* actual_size) {
522 guarantee(false, "thread-local allocation buffers not supported");
523 return NULL;
524 }
525
526 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
527 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
528 "Should only be called at a safepoint or at start-up");
529
530 ThreadLocalAllocStats stats;
531
532 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) {
533 BarrierSet::barrier_set()->make_parsable(thread);
534 if (UseTLAB) {
535 if (retire_tlabs) {
536 thread->tlab().retire(&stats);
537 } else {
538 thread->tlab().make_parsable();
539 }
540 }
541 }
542
543 stats.publish();
544 }
545
546 void CollectedHeap::resize_all_tlabs() {
547 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
548 "Should only resize tlabs at safepoint");
549
550 if (UseTLAB && ResizeTLAB) {
551 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
552 thread->tlab().resize();
553 }
554 }
555 }
556
557 jlong CollectedHeap::millis_since_last_whole_heap_examined() {
558 return (os::javaTimeNanos() - _last_whole_heap_examined_time_ns) / NANOSECS_PER_MILLISEC;
559 }
560
561 void CollectedHeap::record_whole_heap_examined_timestamp() {
562 _last_whole_heap_examined_time_ns = os::javaTimeNanos();
563 }
564
565 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
566 assert(timer != NULL, "timer is null");
567 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
568 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
569 HeapDumper::dump_heap();
570 }
571
572 LogTarget(Trace, gc, classhisto) lt;
573 if (lt.is_enabled()) {
574 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
575 ResourceMark rm;
576 LogStream ls(lt);
577 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
578 inspector.doit();
579 }
580 }
581
582 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
583 full_gc_dump(timer, true);
584 }
585
586 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
587 full_gc_dump(timer, false);
588 }
589
590 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) {
591 // It is important to do this in a way such that concurrent readers can't
592 // temporarily think something is in the heap. (Seen this happen in asserts.)
593 _reserved.set_word_size(0);
594 _reserved.set_start((HeapWord*)rs.base());
595 _reserved.set_end((HeapWord*)rs.end());
596 }
597
598 void CollectedHeap::post_initialize() {
599 StringDedup::initialize();
600 initialize_serviceability();
601 }
602
603 #ifndef PRODUCT
604
605 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
606 // Access to count is not atomic; the value does not have to be exact.
607 if (PromotionFailureALot) {
608 const size_t gc_num = total_collections();
609 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
610 if (elapsed_gcs >= PromotionFailureALotInterval) {
611 // Test for unsigned arithmetic wrap-around.
612 if (++*count >= PromotionFailureALotCount) {
613 *count = 0;
614 return true;
615 }
616 }
617 }
618 return false;
619 }
620
621 bool CollectedHeap::promotion_should_fail() {
622 return promotion_should_fail(&_promotion_failure_alot_count);
623 }
624
625 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
626 if (PromotionFailureALot) {
627 _promotion_failure_alot_gc_number = total_collections();
628 *count = 0;
629 }
630 }
631
632 void CollectedHeap::reset_promotion_should_fail() {
633 reset_promotion_should_fail(&_promotion_failure_alot_count);
634 }
635
636 #endif // #ifndef PRODUCT
637
638 bool CollectedHeap::supports_object_pinning() const {
639 return false;
640 }
641
642 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
643 ShouldNotReachHere();
644 return NULL;
645 }
646
647 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
648 ShouldNotReachHere();
649 }
650
651 bool CollectedHeap::is_archived_object(oop object) const {
652 return false;
653 }
654
655 // It's the caller's responsibility to ensure glitch-freedom
656 // (if required).
657 void CollectedHeap::update_capacity_and_used_at_gc() {
658 _capacity_at_last_gc = capacity();
659 _used_at_last_gc = used();
660 }