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 _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 // Memory state functions.
176
177
178 CollectedHeap::CollectedHeap() :
179 _barrier_set(NULL),
180 _is_gc_active(false),
181 _total_collections(0),
182 _total_full_collections(0),
183 _gc_cause(GCCause::_no_gc),
184 _gc_lastcause(GCCause::_no_gc)
185 {
186 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
187 const size_t elements_per_word = HeapWordSize / sizeof(jint);
188 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
189 max_len / elements_per_word);
190
191 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
192 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
193
194 if (UsePerfData) {
195 EXCEPTION_MARK;
196
197 // create the gc cause jvmstat counters
198 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
199 80, GCCause::to_string(_gc_cause), CHECK);
200
201 _perf_gc_lastcause =
202 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
203 80, GCCause::to_string(_gc_lastcause), CHECK);
204 }
205
206 // Create the ring log
207 if (LogEvents) {
208 _gc_heap_log = new GCHeapLog();
209 } else {
210 _gc_heap_log = NULL;
211 }
212 }
213
214 // This interface assumes that it's being called by the
215 // vm thread. It collects the heap assuming that the
216 // heap lock is already held and that we are executing in
217 // the context of the vm thread.
218 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
219 assert(Thread::current()->is_VM_thread(), "Precondition#1");
220 assert(Heap_lock->is_locked(), "Precondition#2");
221 GCCauseSetter gcs(this, cause);
222 switch (cause) {
223 case GCCause::_heap_inspection:
224 case GCCause::_heap_dump:
225 case GCCause::_metadata_GC_threshold : {
226 HandleMark hm;
227 do_full_collection(false); // don't clear all soft refs
228 break;
229 }
230 case GCCause::_metadata_GC_clear_soft_refs: {
231 HandleMark hm;
232 do_full_collection(true); // do clear all soft refs
233 break;
234 }
235 default:
236 ShouldNotReachHere(); // Unexpected use of this function
237 }
238 }
239
240 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
241 size_t word_size,
242 Metaspace::MetadataType mdtype) {
243 uint loop_count = 0;
244 uint gc_count = 0;
245 uint full_gc_count = 0;
246
247 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
248
249 do {
250 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
251 if (result != NULL) {
252 return result;
253 }
254
255 if (GCLocker::is_active_and_needs_gc()) {
256 // If the GCLocker is active, just expand and allocate.
257 // If that does not succeed, wait if this thread is not
258 // in a critical section itself.
259 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
260 if (result != NULL) {
261 return result;
262 }
263 JavaThread* jthr = JavaThread::current();
264 if (!jthr->in_critical()) {
265 // Wait for JNI critical section to be exited
266 GCLocker::stall_until_clear();
267 // The GC invoked by the last thread leaving the critical
268 // section will be a young collection and a full collection
269 // is (currently) needed for unloading classes so continue
270 // to the next iteration to get a full GC.
271 continue;
272 } else {
273 if (CheckJNICalls) {
274 fatal("Possible deadlock due to allocating while"
275 " in jni critical section");
276 }
277 return NULL;
278 }
279 }
280
281 { // Need lock to get self consistent gc_count's
282 MutexLocker ml(Heap_lock);
283 gc_count = Universe::heap()->total_collections();
284 full_gc_count = Universe::heap()->total_full_collections();
285 }
286
287 // Generate a VM operation
288 VM_CollectForMetadataAllocation op(loader_data,
289 word_size,
290 mdtype,
291 gc_count,
292 full_gc_count,
293 GCCause::_metadata_GC_threshold);
294 VMThread::execute(&op);
295
296 // If GC was locked out, try again. Check before checking success because the
297 // prologue could have succeeded and the GC still have been locked out.
298 if (op.gc_locked()) {
299 continue;
300 }
301
302 if (op.prologue_succeeded()) {
303 return op.result();
304 }
305 loop_count++;
306 if ((QueuedAllocationWarningCount > 0) &&
307 (loop_count % QueuedAllocationWarningCount == 0)) {
308 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
309 " size=" SIZE_FORMAT, loop_count, word_size);
310 }
311 } while (true); // Until a GC is done
312 }
313
314 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
315 _barrier_set = barrier_set;
316 BarrierSet::set_bs(barrier_set);
317 }
318
319 #ifndef PRODUCT
320 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
321 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
322 for (size_t slot = 0; slot < size; slot += 1) {
323 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
324 "Found badHeapWordValue in post-allocation check");
325 }
326 }
327 }
328
329 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
330 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
331 for (size_t slot = 0; slot < size; slot += 1) {
332 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
333 "Found non badHeapWordValue in pre-allocation check");
334 }
335 }
336 }
337 #endif // PRODUCT
338
339 #ifdef ASSERT
340 void CollectedHeap::check_for_valid_allocation_state() {
341 Thread *thread = Thread::current();
342 // How to choose between a pending exception and a potential
343 // OutOfMemoryError? Don't allow pending exceptions.
344 // This is a VM policy failure, so how do we exhaustively test it?
345 assert(!thread->has_pending_exception(),
346 "shouldn't be allocating with pending exception");
347 if (StrictSafepointChecks) {
348 assert(thread->allow_allocation(),
349 "Allocation done by thread for which allocation is blocked "
350 "by No_Allocation_Verifier!");
351 // Allocation of an oop can always invoke a safepoint,
352 // hence, the true argument
353 thread->check_for_valid_safepoint_state(true);
354 }
355 }
356 #endif
357
358 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
359
360 // Retain tlab and allocate object in shared space if
361 // the amount free in the tlab is too large to discard.
362 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
363 thread->tlab().record_slow_allocation(size);
364 return NULL;
365 }
366
367 // Discard tlab and allocate a new one.
368 // To minimize fragmentation, the last TLAB may be smaller than the rest.
369 size_t new_tlab_size = thread->tlab().compute_size(size);
370
371 thread->tlab().clear_before_allocation();
372
373 if (new_tlab_size == 0) {
374 return NULL;
375 }
376
377 // Allocate a new TLAB...
378 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
379 if (obj == NULL) {
380 return NULL;
381 }
382
383 AllocTracer::send_allocation_in_new_tlab(klass, obj, new_tlab_size * HeapWordSize, size * HeapWordSize, thread);
384
385 if (ZeroTLAB) {
386 // ..and clear it.
387 Copy::zero_to_words(obj, new_tlab_size);
388 } else {
389 // ...and zap just allocated object.
390 #ifdef ASSERT
391 // Skip mangling the space corresponding to the object header to
392 // ensure that the returned space is not considered parsable by
393 // any concurrent GC thread.
394 size_t hdr_size = oopDesc::header_size();
395 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
396 #endif // ASSERT
397 }
398 thread->tlab().fill(obj, obj + size, new_tlab_size);
399 return obj;
400 }
401
402 size_t CollectedHeap::max_tlab_size() const {
403 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
404 // This restriction could be removed by enabling filling with multiple arrays.
405 // If we compute that the reasonable way as
406 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
407 // we'll overflow on the multiply, so we do the divide first.
408 // We actually lose a little by dividing first,
409 // but that just makes the TLAB somewhat smaller than the biggest array,
410 // which is fine, since we'll be able to fill that.
411 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
412 sizeof(jint) *
413 ((juint) max_jint / (size_t) HeapWordSize);
414 return align_down(max_int_size, MinObjAlignment);
415 }
416
417 size_t CollectedHeap::filler_array_hdr_size() {
418 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
419 }
420
421 size_t CollectedHeap::filler_array_min_size() {
422 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
423 }
424
425 #ifdef ASSERT
426 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
427 {
428 assert(words >= min_fill_size(), "too small to fill");
429 assert(is_object_aligned(words), "unaligned size");
430 assert(Universe::heap()->is_in_reserved(start), "not in heap");
431 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
432 }
433
434 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
435 {
436 if (ZapFillerObjects && zap) {
437 Copy::fill_to_words(start + filler_array_hdr_size(),
438 words - filler_array_hdr_size(), 0XDEAFBABE);
439 }
440 }
441 #endif // ASSERT
442
443 void
444 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
445 {
446 assert(words >= filler_array_min_size(), "too small for an array");
447 assert(words <= filler_array_max_size(), "too big for a single object");
448
449 const size_t payload_size = words - filler_array_hdr_size();
450 const size_t len = payload_size * HeapWordSize / sizeof(jint);
451 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
452
453 // Set the length first for concurrent GC.
454 ((arrayOop)start)->set_length((int)len);
455 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
456 DEBUG_ONLY(zap_filler_array(start, words, zap);)
457 }
458
459 void
460 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
461 {
462 assert(words <= filler_array_max_size(), "too big for a single object");
463
464 if (words >= filler_array_min_size()) {
465 fill_with_array(start, words, zap);
466 } else if (words > 0) {
467 assert(words == min_fill_size(), "unaligned size");
468 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
469 }
470 }
471
472 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
473 {
474 DEBUG_ONLY(fill_args_check(start, words);)
475 HandleMark hm; // Free handles before leaving.
476 fill_with_object_impl(start, words, zap);
477 }
478
479 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
480 {
481 DEBUG_ONLY(fill_args_check(start, words);)
482 HandleMark hm; // Free handles before leaving.
483
484 // Multiple objects may be required depending on the filler array maximum size. Fill
485 // the range up to that with objects that are filler_array_max_size sized. The
486 // remainder is filled with a single object.
487 const size_t min = min_fill_size();
488 const size_t max = filler_array_max_size();
489 while (words > max) {
490 const size_t cur = (words - max) >= min ? max : max - min;
491 fill_with_array(start, cur, zap);
492 start += cur;
493 words -= cur;
494 }
495
496 fill_with_object_impl(start, words, zap);
497 }
498
499 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
500 guarantee(false, "thread-local allocation buffers not supported");
501 return NULL;
502 }
503
504 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
505 // The second disjunct in the assertion below makes a concession
506 // for the start-up verification done while the VM is being
507 // created. Callers be careful that you know that mutators
508 // aren't going to interfere -- for instance, this is permissible
509 // if we are still single-threaded and have either not yet
510 // started allocating (nothing much to verify) or we have
511 // started allocating but are now a full-fledged JavaThread
512 // (and have thus made our TLAB's) available for filling.
513 assert(SafepointSynchronize::is_at_safepoint() ||
514 !is_init_completed(),
515 "Should only be called at a safepoint or at start-up"
516 " otherwise concurrent mutator activity may make heap "
517 " unparsable again");
518 const bool use_tlab = UseTLAB;
519 // The main thread starts allocating via a TLAB even before it
520 // has added itself to the threads list at vm boot-up.
521 JavaThreadIteratorWithHandle jtiwh;
522 assert(!use_tlab || jtiwh.length() > 0,
523 "Attempt to fill tlabs before main thread has been added"
524 " to threads list is doomed to failure!");
525 BarrierSet *bs = barrier_set();
526 for (; JavaThread *thread = jtiwh.next(); ) {
527 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
528 bs->make_parsable(thread);
529 }
530 }
531
532 void CollectedHeap::accumulate_statistics_all_tlabs() {
533 if (UseTLAB) {
534 assert(SafepointSynchronize::is_at_safepoint() ||
535 !is_init_completed(),
536 "should only accumulate statistics on tlabs at safepoint");
537
538 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
539 }
540 }
541
542 void CollectedHeap::resize_all_tlabs() {
543 if (UseTLAB) {
544 assert(SafepointSynchronize::is_at_safepoint() ||
545 !is_init_completed(),
546 "should only resize tlabs at safepoint");
547
548 ThreadLocalAllocBuffer::resize_all_tlabs();
549 }
550 }
551
552 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
553 assert(timer != NULL, "timer is null");
554 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
555 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
556 HeapDumper::dump_heap();
557 }
558
559 LogTarget(Trace, gc, classhisto) lt;
560 if (lt.is_enabled()) {
561 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
562 ResourceMark rm;
563 LogStream ls(lt);
564 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
565 inspector.doit();
566 }
567 }
568
569 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
570 full_gc_dump(timer, true);
571 }
572
573 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
574 full_gc_dump(timer, false);
575 }
576
577 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
578 // It is important to do this in a way such that concurrent readers can't
579 // temporarily think something is in the heap. (Seen this happen in asserts.)
580 _reserved.set_word_size(0);
581 _reserved.set_start(start);
582 _reserved.set_end(end);
583 }
584
585 void CollectedHeap::post_initialize() {
586 initialize_serviceability();
587 }
588
589 #ifndef PRODUCT
590
591 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
592 // Access to count is not atomic; the value does not have to be exact.
593 if (PromotionFailureALot) {
594 const size_t gc_num = total_collections();
595 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
596 if (elapsed_gcs >= PromotionFailureALotInterval) {
597 // Test for unsigned arithmetic wrap-around.
598 if (++*count >= PromotionFailureALotCount) {
599 *count = 0;
600 return true;
601 }
602 }
603 }
604 return false;
605 }
606
607 bool CollectedHeap::promotion_should_fail() {
608 return promotion_should_fail(&_promotion_failure_alot_count);
609 }
610
611 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
612 if (PromotionFailureALot) {
613 _promotion_failure_alot_gc_number = total_collections();
614 *count = 0;
615 }
616 }
617
618 void CollectedHeap::reset_promotion_should_fail() {
619 reset_promotion_should_fail(&_promotion_failure_alot_count);
620 }
621
622 #endif // #ifndef PRODUCT
623
624 oop CollectedHeap::pin_object(JavaThread* thread, oop o) {
625 Handle handle(thread, o);
626 GCLocker::lock_critical(thread);
627 return handle();
628 }
629
630 void CollectedHeap::unpin_object(JavaThread* thread, oop o) {
631 GCLocker::unlock_critical(thread);
632 }