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::_heap_inspection:
294 case GCCause::_heap_dump:
295 case GCCause::_metadata_GC_threshold : {
296 HandleMark hm(thread);
297 do_full_collection(false); // don't clear all soft refs
298 break;
299 }
300 case GCCause::_archive_time_gc:
301 case GCCause::_metadata_GC_clear_soft_refs: {
302 HandleMark hm(thread);
303 do_full_collection(true); // do clear all soft refs
304 break;
305 }
306 default:
307 ShouldNotReachHere(); // Unexpected use of this function
308 }
309 }
310
311 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
312 size_t word_size,
313 Metaspace::MetadataType mdtype) {
314 uint loop_count = 0;
315 uint gc_count = 0;
316 uint full_gc_count = 0;
317
318 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
319
320 do {
321 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
322 if (result != NULL) {
323 return result;
324 }
325
326 if (GCLocker::is_active_and_needs_gc()) {
327 // If the GCLocker is active, just expand and allocate.
328 // If that does not succeed, wait if this thread is not
329 // in a critical section itself.
330 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
331 if (result != NULL) {
332 return result;
333 }
334 JavaThread* jthr = JavaThread::current();
335 if (!jthr->in_critical()) {
336 // Wait for JNI critical section to be exited
337 GCLocker::stall_until_clear();
338 // The GC invoked by the last thread leaving the critical
339 // section will be a young collection and a full collection
340 // is (currently) needed for unloading classes so continue
341 // to the next iteration to get a full GC.
342 continue;
343 } else {
344 if (CheckJNICalls) {
345 fatal("Possible deadlock due to allocating while"
346 " in jni critical section");
347 }
348 return NULL;
349 }
350 }
351
352 { // Need lock to get self consistent gc_count's
353 MutexLocker ml(Heap_lock);
354 gc_count = Universe::heap()->total_collections();
355 full_gc_count = Universe::heap()->total_full_collections();
356 }
357
358 // Generate a VM operation
359 VM_CollectForMetadataAllocation op(loader_data,
360 word_size,
361 mdtype,
362 gc_count,
363 full_gc_count,
364 GCCause::_metadata_GC_threshold);
365 VMThread::execute(&op);
366
367 // If GC was locked out, try again. Check before checking success because the
368 // prologue could have succeeded and the GC still have been locked out.
369 if (op.gc_locked()) {
370 continue;
371 }
372
373 if (op.prologue_succeeded()) {
374 return op.result();
375 }
376 loop_count++;
377 if ((QueuedAllocationWarningCount > 0) &&
378 (loop_count % QueuedAllocationWarningCount == 0)) {
379 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
380 " size=" SIZE_FORMAT, loop_count, word_size);
381 }
382 } while (true); // Until a GC is done
383 }
384
385 MemoryUsage CollectedHeap::memory_usage() {
386 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity());
387 }
388
389 void CollectedHeap::set_gc_cause(GCCause::Cause v) {
390 if (UsePerfData) {
391 _gc_lastcause = _gc_cause;
392 _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause));
393 _perf_gc_cause->set_value(GCCause::to_string(v));
394 }
395 _gc_cause = v;
396 }
397
398 #ifndef PRODUCT
399 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
400 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
401 // please note mismatch between size (in 32/64 bit words), and ju_addr that always point to a 32 bit word
402 for (juint* ju_addr = reinterpret_cast<juint*>(addr); ju_addr < reinterpret_cast<juint*>(addr + size); ++ju_addr) {
403 assert(*ju_addr == badHeapWordVal, "Found non badHeapWordValue in pre-allocation check");
404 }
405 }
406 }
407 #endif // PRODUCT
408
409 size_t CollectedHeap::max_tlab_size() const {
410 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
411 // This restriction could be removed by enabling filling with multiple arrays.
412 // If we compute that the reasonable way as
413 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
414 // we'll overflow on the multiply, so we do the divide first.
415 // We actually lose a little by dividing first,
416 // but that just makes the TLAB somewhat smaller than the biggest array,
417 // which is fine, since we'll be able to fill that.
418 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
419 sizeof(jint) *
420 ((juint) max_jint / (size_t) HeapWordSize);
421 return align_down(max_int_size, MinObjAlignment);
422 }
423
424 size_t CollectedHeap::filler_array_hdr_size() {
425 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
426 }
427
428 size_t CollectedHeap::filler_array_min_size() {
429 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
430 }
431
432 void CollectedHeap::zap_filler_array_with(HeapWord* start, size_t words, juint value) {
433 Copy::fill_to_words(start + filler_array_hdr_size(),
434 words - filler_array_hdr_size(), value);
435 }
436
437 #ifdef ASSERT
438 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
439 {
440 assert(words >= min_fill_size(), "too small to fill");
441 assert(is_object_aligned(words), "unaligned size");
442 }
443
444 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
445 {
446 if (ZapFillerObjects && zap) {
447 zap_filler_array_with(start, words, 0XDEAFBABE);
448 }
449 }
450 #endif // ASSERT
451
452 void
453 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
454 {
455 assert(words >= filler_array_min_size(), "too small for an array");
456 assert(words <= filler_array_max_size(), "too big for a single object");
457
458 const size_t payload_size = words - filler_array_hdr_size();
459 const size_t len = payload_size * HeapWordSize / sizeof(jint);
460 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
461
462 ObjArrayAllocator allocator(Universe::fillerArrayKlassObj(), words, (int)len, /* do_zero */ false);
463 allocator.initialize(start);
464 if (DumpSharedSpaces) {
465 // This array is written into the CDS archive. Make sure it
466 // has deterministic contents.
467 zap_filler_array_with(start, words, 0);
468 } else {
469 DEBUG_ONLY(zap_filler_array(start, words, zap);)
470 }
471 }
472
473 void
474 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
475 {
476 assert(words <= filler_array_max_size(), "too big for a single object");
477
478 if (words >= filler_array_min_size()) {
479 fill_with_array(start, words, zap);
480 } else if (words > 0) {
481 assert(words == min_fill_size(), "unaligned size");
482 ObjAllocator allocator(CollectedHeap::filler_object_klass(), words);
483 allocator.initialize(start);
484 }
485 }
486
487 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
488 {
489 DEBUG_ONLY(fill_args_check(start, words);)
490 HandleMark hm(Thread::current()); // Free handles before leaving.
491 fill_with_object_impl(start, words, zap);
492 }
493
494 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
495 {
496 DEBUG_ONLY(fill_args_check(start, words);)
497 HandleMark hm(Thread::current()); // Free handles before leaving.
498
499 // Multiple objects may be required depending on the filler array maximum size. Fill
500 // the range up to that with objects that are filler_array_max_size sized. The
501 // remainder is filled with a single object.
502 const size_t min = min_fill_size();
503 const size_t max = filler_array_max_size();
504 while (words > max) {
505 const size_t cur = (words - max) >= min ? max : max - min;
506 fill_with_array(start, cur, zap);
507 start += cur;
508 words -= cur;
509 }
510
511 fill_with_object_impl(start, words, zap);
512 }
513
514 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
515 CollectedHeap::fill_with_object(start, end, zap);
516 }
517
518 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
519 size_t requested_size,
520 size_t* actual_size) {
521 guarantee(false, "thread-local allocation buffers not supported");
522 return NULL;
523 }
524
525 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
526 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
527 "Should only be called at a safepoint or at start-up");
528
529 ThreadLocalAllocStats stats;
530
531 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) {
532 BarrierSet::barrier_set()->make_parsable(thread);
533 if (UseTLAB) {
534 if (retire_tlabs) {
535 thread->tlab().retire(&stats);
536 } else {
537 thread->tlab().make_parsable();
538 }
539 }
540 }
541
542 stats.publish();
543 }
544
545 void CollectedHeap::resize_all_tlabs() {
546 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
547 "Should only resize tlabs at safepoint");
548
549 if (UseTLAB && ResizeTLAB) {
550 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
551 thread->tlab().resize();
552 }
553 }
554 }
555
556 jlong CollectedHeap::millis_since_last_whole_heap_examined() {
557 return (os::javaTimeNanos() - _last_whole_heap_examined_time_ns) / NANOSECS_PER_MILLISEC;
558 }
559
560 void CollectedHeap::record_whole_heap_examined_timestamp() {
561 _last_whole_heap_examined_time_ns = os::javaTimeNanos();
562 }
563
564 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
565 assert(timer != NULL, "timer is null");
566 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
567 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
568 HeapDumper::dump_heap();
569 }
570
571 LogTarget(Trace, gc, classhisto) lt;
572 if (lt.is_enabled()) {
573 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
574 ResourceMark rm;
575 LogStream ls(lt);
576 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
577 inspector.doit();
578 }
579 }
580
581 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
582 full_gc_dump(timer, true);
583 }
584
585 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
586 full_gc_dump(timer, false);
587 }
588
589 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) {
590 // It is important to do this in a way such that concurrent readers can't
591 // temporarily think something is in the heap. (Seen this happen in asserts.)
592 _reserved.set_word_size(0);
593 _reserved.set_start((HeapWord*)rs.base());
594 _reserved.set_end((HeapWord*)rs.end());
595 }
596
597 void CollectedHeap::post_initialize() {
598 StringDedup::initialize();
599 initialize_serviceability();
600 }
601
602 #ifndef PRODUCT
603
604 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
605 // Access to count is not atomic; the value does not have to be exact.
606 if (PromotionFailureALot) {
607 const size_t gc_num = total_collections();
608 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
609 if (elapsed_gcs >= PromotionFailureALotInterval) {
610 // Test for unsigned arithmetic wrap-around.
611 if (++*count >= PromotionFailureALotCount) {
612 *count = 0;
613 return true;
614 }
615 }
616 }
617 return false;
618 }
619
620 bool CollectedHeap::promotion_should_fail() {
621 return promotion_should_fail(&_promotion_failure_alot_count);
622 }
623
624 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
625 if (PromotionFailureALot) {
626 _promotion_failure_alot_gc_number = total_collections();
627 *count = 0;
628 }
629 }
630
631 void CollectedHeap::reset_promotion_should_fail() {
632 reset_promotion_should_fail(&_promotion_failure_alot_count);
633 }
634
635 #endif // #ifndef PRODUCT
636
637 bool CollectedHeap::supports_object_pinning() const {
638 return false;
639 }
640
641 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
642 ShouldNotReachHere();
643 return NULL;
644 }
645
646 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
647 ShouldNotReachHere();
648 }
649
650 bool CollectedHeap::is_archived_object(oop object) const {
651 return false;
652 }
653
654 uint32_t CollectedHeap::hash_oop(oop obj) const {
655 const uintptr_t addr = cast_from_oop<uintptr_t>(obj);
656 return static_cast<uint32_t>(addr >> LogMinObjAlignment);
657 }
658
659 // It's the caller's responsibility to ensure glitch-freedom
660 // (if required).
661 void CollectedHeap::update_capacity_and_used_at_gc() {
662 _capacity_at_last_gc = capacity();
663 _used_at_last_gc = used();
664 }