1 /*
2 * Copyright (c) 2001, 2017, 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.inline.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "gc/shared/gcHeapSummary.hpp"
32 #include "gc/shared/gcTrace.hpp"
33 #include "gc/shared/gcTraceTime.inline.hpp"
34 #include "gc/shared/gcWhen.hpp"
35 #include "gc/shared/vmGCOperations.hpp"
36 #include "logging/log.hpp"
37 #include "memory/metaspace.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/instanceMirrorKlass.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "runtime/heapMonitoring.hpp"
42 #include "runtime/init.hpp"
43 #include "runtime/thread.inline.hpp"
44 #include "services/heapDumper.hpp"
45 #include "utilities/align.hpp"
46
47
48 #ifdef ASSERT
49 int CollectedHeap::_fire_out_of_memory_count = 0;
50 #endif
51
52 size_t CollectedHeap::_filler_array_max_size = 0;
53
54 template <>
55 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
56 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
57 st->print_raw(m);
58 }
59
60 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
61 if (!should_log()) {
62 return;
63 }
64
65 double timestamp = fetch_timestamp();
66 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
67 int index = compute_log_index();
68 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
69 _records[index].timestamp = timestamp;
70 _records[index].data.is_before = before;
71 stringStream st(_records[index].data.buffer(), _records[index].data.size());
72
73 st.print_cr("{Heap %s GC invocations=%u (full %u):",
74 before ? "before" : "after",
75 heap->total_collections(),
76 heap->total_full_collections());
77
78 heap->print_on(&st);
79 st.print_cr("}");
80 }
81
82 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
83 size_t capacity_in_words = capacity() / HeapWordSize;
84
85 return VirtualSpaceSummary(
86 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
87 }
88
89 GCHeapSummary CollectedHeap::create_heap_summary() {
90 VirtualSpaceSummary heap_space = create_heap_space_summary();
91 return GCHeapSummary(heap_space, used());
92 }
93
94 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
95 const MetaspaceSizes meta_space(
96 MetaspaceAux::committed_bytes(),
97 MetaspaceAux::used_bytes(),
98 MetaspaceAux::reserved_bytes());
99 const MetaspaceSizes data_space(
100 MetaspaceAux::committed_bytes(Metaspace::NonClassType),
101 MetaspaceAux::used_bytes(Metaspace::NonClassType),
102 MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
103 const MetaspaceSizes class_space(
104 MetaspaceAux::committed_bytes(Metaspace::ClassType),
105 MetaspaceAux::used_bytes(Metaspace::ClassType),
106 MetaspaceAux::reserved_bytes(Metaspace::ClassType));
107
108 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
109 MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
110 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
111 MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
112
113 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
114 ms_chunk_free_list_summary, class_chunk_free_list_summary);
115 }
116
117 void CollectedHeap::print_heap_before_gc() {
118 Universe::print_heap_before_gc();
119 if (_gc_heap_log != NULL) {
120 _gc_heap_log->log_heap_before(this);
121 }
122 }
123
124 void CollectedHeap::print_heap_after_gc() {
125 Universe::print_heap_after_gc();
126 if (_gc_heap_log != NULL) {
127 _gc_heap_log->log_heap_after(this);
128 }
129 }
130
131 void CollectedHeap::print_on_error(outputStream* st) const {
132 st->print_cr("Heap:");
133 print_extended_on(st);
134 st->cr();
135
136 _barrier_set->print_on(st);
137 }
138
139 void CollectedHeap::register_nmethod(nmethod* nm) {
140 assert_locked_or_safepoint(CodeCache_lock);
141 }
142
143 void CollectedHeap::unregister_nmethod(nmethod* nm) {
144 assert_locked_or_safepoint(CodeCache_lock);
145 }
146
147 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
148 const GCHeapSummary& heap_summary = create_heap_summary();
149 gc_tracer->report_gc_heap_summary(when, heap_summary);
150
151 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
152 gc_tracer->report_metaspace_summary(when, metaspace_summary);
153 }
154
155 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
156 trace_heap(GCWhen::BeforeGC, gc_tracer);
157 }
158
159 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
160 trace_heap(GCWhen::AfterGC, gc_tracer);
161 }
162
163 // WhiteBox API support for concurrent collectors. These are the
164 // default implementations, for collectors which don't support this
165 // feature.
166 bool CollectedHeap::supports_concurrent_phase_control() const {
167 return false;
168 }
169
170 const char* const* CollectedHeap::concurrent_phases() const {
171 static const char* const result[] = { NULL };
172 return result;
173 }
174
175 bool CollectedHeap::request_concurrent_phase(const char* phase) {
176 return false;
177 }
178
179 // Memory state functions.
180
181
182 CollectedHeap::CollectedHeap() :
183 _barrier_set(NULL),
184 _is_gc_active(false),
185 _total_collections(0),
186 _total_full_collections(0),
187 _gc_cause(GCCause::_no_gc),
188 _gc_lastcause(GCCause::_no_gc),
189 _defer_initial_card_mark(false) // strengthened by subclass in pre_initialize() below.
190 {
191 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
192 const size_t elements_per_word = HeapWordSize / sizeof(jint);
193 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
194 max_len / elements_per_word);
195
196 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
197 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
198
199 if (UsePerfData) {
200 EXCEPTION_MARK;
201
202 // create the gc cause jvmstat counters
203 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
204 80, GCCause::to_string(_gc_cause), CHECK);
205
206 _perf_gc_lastcause =
207 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
208 80, GCCause::to_string(_gc_lastcause), CHECK);
209 }
210
211 // Create the ring log
212 if (LogEvents) {
213 _gc_heap_log = new GCHeapLog();
214 } else {
215 _gc_heap_log = NULL;
216 }
217 }
218
219 // This interface assumes that it's being called by the
220 // vm thread. It collects the heap assuming that the
221 // heap lock is already held and that we are executing in
222 // the context of the vm thread.
223 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
224 assert(Thread::current()->is_VM_thread(), "Precondition#1");
225 assert(Heap_lock->is_locked(), "Precondition#2");
226 GCCauseSetter gcs(this, cause);
227 switch (cause) {
228 case GCCause::_heap_inspection:
229 case GCCause::_heap_dump:
230 case GCCause::_metadata_GC_threshold : {
231 HandleMark hm;
232 do_full_collection(false); // don't clear all soft refs
233 break;
234 }
235 case GCCause::_metadata_GC_clear_soft_refs: {
236 HandleMark hm;
237 do_full_collection(true); // do clear all soft refs
238 break;
239 }
240 default:
241 ShouldNotReachHere(); // Unexpected use of this function
242 }
243 }
244
245 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
246 _barrier_set = barrier_set;
247 oopDesc::set_bs(_barrier_set);
248 }
249
250 void CollectedHeap::pre_initialize() {
251 // Used for ReduceInitialCardMarks (when COMPILER2 is used);
252 // otherwise remains unused.
253 #if defined(COMPILER2) || INCLUDE_JVMCI
254 _defer_initial_card_mark = is_server_compilation_mode_vm() && ReduceInitialCardMarks && can_elide_tlab_store_barriers()
255 && (DeferInitialCardMark || card_mark_must_follow_store());
256 #else
257 assert(_defer_initial_card_mark == false, "Who would set it?");
258 #endif
259 }
260
261 #ifndef PRODUCT
262 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
263 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
264 for (size_t slot = 0; slot < size; slot += 1) {
265 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
266 "Found badHeapWordValue in post-allocation check");
267 }
268 }
269 }
270
271 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
272 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
273 for (size_t slot = 0; slot < size; slot += 1) {
274 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
275 "Found non badHeapWordValue in pre-allocation check");
276 }
277 }
278 }
279 #endif // PRODUCT
280
281 #ifdef ASSERT
282 void CollectedHeap::check_for_valid_allocation_state() {
283 Thread *thread = Thread::current();
284 // How to choose between a pending exception and a potential
285 // OutOfMemoryError? Don't allow pending exceptions.
286 // This is a VM policy failure, so how do we exhaustively test it?
287 assert(!thread->has_pending_exception(),
288 "shouldn't be allocating with pending exception");
289 if (StrictSafepointChecks) {
290 assert(thread->allow_allocation(),
291 "Allocation done by thread for which allocation is blocked "
292 "by No_Allocation_Verifier!");
293 // Allocation of an oop can always invoke a safepoint,
294 // hence, the true argument
295 thread->check_for_valid_safepoint_state(true);
296 }
297 }
298 #endif
299
300 HeapWord* CollectedHeap::handle_heap_sampling(Thread* thread, HeapWord* obj, size_t size) {
301 // We can come here for three reasons:
302 // - We either really did fill the tlab.
303 // - We pretended to everyone we did and we want to sample.
304 // - Both of the above reasons are true at the same time.
305 if (HeapMonitoring::enabled()) {
306 if (thread->tlab().should_sample()) {
307 // If we don't have an object yet, try to allocate it.
308 if (obj == NULL) {
309 // The tlab could still have space after this sample.
310 thread->tlab().set_back_actual_end();
311 obj = thread->tlab().allocate(size);
312 }
313
314 // Is the object allocated now?
315 // If not, this means we have to wait till a new TLAB, let the subsequent
316 // call to handle_heap_sampling pick the next sample.
317 if (obj != NULL) {
318 // Object is allocated, sample it now.
319 HeapMonitoring::object_alloc_do_sample(thread,
320 reinterpret_cast<oopDesc*>(obj),
321 size);
322 // Pick a next sample in this case, we allocated right.
323 thread->tlab().pick_next_sample();
324 }
325 }
326 }
327
328 return obj;
329 }
330
331 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
332 HeapWord* obj = handle_heap_sampling(thread, NULL, size);
333
334 if (obj != NULL) {
335 return obj;
336 }
337
338 // Retain tlab and allocate object in shared space if
339 // the amount free in the tlab is too large to discard.
340 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
341 thread->tlab().record_slow_allocation(size);
342 return NULL;
343 }
344
345 // Discard tlab and allocate a new one.
346 // To minimize fragmentation, the last TLAB may be smaller than the rest.
347 size_t new_tlab_size = thread->tlab().compute_size(size);
348
349 thread->tlab().clear_before_allocation();
350
351 if (new_tlab_size == 0) {
352 return NULL;
353 }
354
355 // Allocate a new TLAB...
356 obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
357 if (obj == NULL) {
358 return NULL;
359 }
360
361 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
362
363 if (ZeroTLAB) {
364 // ..and clear it.
365 Copy::zero_to_words(obj, new_tlab_size);
366 } else {
367 // ...and zap just allocated object.
368 #ifdef ASSERT
369 // Skip mangling the space corresponding to the object header to
370 // ensure that the returned space is not considered parsable by
371 // any concurrent GC thread.
372 size_t hdr_size = oopDesc::header_size();
373 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
374 #endif // ASSERT
375 }
376 thread->tlab().fill(obj, obj + size, new_tlab_size);
377 handle_heap_sampling(thread, obj, size);
378 return obj;
379 }
380
381 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
382 MemRegion deferred = thread->deferred_card_mark();
383 if (!deferred.is_empty()) {
384 assert(_defer_initial_card_mark, "Otherwise should be empty");
385 {
386 // Verify that the storage points to a parsable object in heap
387 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
388 assert(is_in(old_obj), "Not in allocated heap");
389 assert(!can_elide_initializing_store_barrier(old_obj),
390 "Else should have been filtered in new_store_pre_barrier()");
391 assert(oopDesc::is_oop(old_obj, true), "Not an oop");
392 assert(deferred.word_size() == (size_t)(old_obj->size()),
393 "Mismatch: multiple objects?");
394 }
395 BarrierSet* bs = barrier_set();
396 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
397 bs->write_region(deferred);
398 // "Clear" the deferred_card_mark field
399 thread->set_deferred_card_mark(MemRegion());
400 }
401 assert(thread->deferred_card_mark().is_empty(), "invariant");
402 }
403
404 size_t CollectedHeap::max_tlab_size() const {
405 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
406 // This restriction could be removed by enabling filling with multiple arrays.
407 // If we compute that the reasonable way as
408 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
409 // we'll overflow on the multiply, so we do the divide first.
410 // We actually lose a little by dividing first,
411 // but that just makes the TLAB somewhat smaller than the biggest array,
412 // which is fine, since we'll be able to fill that.
413 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
414 sizeof(jint) *
415 ((juint) max_jint / (size_t) HeapWordSize);
416 return align_down(max_int_size, MinObjAlignment);
417 }
418
419 // Helper for ReduceInitialCardMarks. For performance,
420 // compiled code may elide card-marks for initializing stores
421 // to a newly allocated object along the fast-path. We
422 // compensate for such elided card-marks as follows:
423 // (a) Generational, non-concurrent collectors, such as
424 // GenCollectedHeap(ParNew,DefNew,Tenured) and
425 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
426 // need the card-mark if and only if the region is
427 // in the old gen, and do not care if the card-mark
428 // succeeds or precedes the initializing stores themselves,
429 // so long as the card-mark is completed before the next
430 // scavenge. For all these cases, we can do a card mark
431 // at the point at which we do a slow path allocation
432 // in the old gen, i.e. in this call.
433 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
434 // in addition that the card-mark for an old gen allocated
435 // object strictly follow any associated initializing stores.
436 // In these cases, the memRegion remembered below is
437 // used to card-mark the entire region either just before the next
438 // slow-path allocation by this thread or just before the next scavenge or
439 // CMS-associated safepoint, whichever of these events happens first.
440 // (The implicit assumption is that the object has been fully
441 // initialized by this point, a fact that we assert when doing the
442 // card-mark.)
443 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
444 // G1 concurrent marking is in progress an SATB (pre-write-)barrier
445 // is used to remember the pre-value of any store. Initializing
446 // stores will not need this barrier, so we need not worry about
447 // compensating for the missing pre-barrier here. Turning now
448 // to the post-barrier, we note that G1 needs a RS update barrier
449 // which simply enqueues a (sequence of) dirty cards which may
450 // optionally be refined by the concurrent update threads. Note
451 // that this barrier need only be applied to a non-young write,
452 // but, like in CMS, because of the presence of concurrent refinement
453 // (much like CMS' precleaning), must strictly follow the oop-store.
454 // Thus, using the same protocol for maintaining the intended
455 // invariants turns out, serendepitously, to be the same for both
456 // G1 and CMS.
457 //
458 // For any future collector, this code should be reexamined with
459 // that specific collector in mind, and the documentation above suitably
460 // extended and updated.
461 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
462 // If a previous card-mark was deferred, flush it now.
463 flush_deferred_store_barrier(thread);
464 if (can_elide_initializing_store_barrier(new_obj) ||
465 new_obj->is_typeArray()) {
466 // Arrays of non-references don't need a pre-barrier.
467 // The deferred_card_mark region should be empty
468 // following the flush above.
469 assert(thread->deferred_card_mark().is_empty(), "Error");
470 } else {
471 MemRegion mr((HeapWord*)new_obj, new_obj->size());
472 assert(!mr.is_empty(), "Error");
473 if (_defer_initial_card_mark) {
474 // Defer the card mark
475 thread->set_deferred_card_mark(mr);
476 } else {
477 // Do the card mark
478 BarrierSet* bs = barrier_set();
479 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
480 bs->write_region(mr);
481 }
482 }
483 return new_obj;
484 }
485
486 size_t CollectedHeap::filler_array_hdr_size() {
487 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
488 }
489
490 size_t CollectedHeap::filler_array_min_size() {
491 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
492 }
493
494 #ifdef ASSERT
495 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
496 {
497 assert(words >= min_fill_size(), "too small to fill");
498 assert(is_object_aligned(words), "unaligned size");
499 assert(Universe::heap()->is_in_reserved(start), "not in heap");
500 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
501 }
502
503 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
504 {
505 if (ZapFillerObjects && zap) {
506 Copy::fill_to_words(start + filler_array_hdr_size(),
507 words - filler_array_hdr_size(), 0XDEAFBABE);
508 }
509 }
510 #endif // ASSERT
511
512 void
513 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
514 {
515 assert(words >= filler_array_min_size(), "too small for an array");
516 assert(words <= filler_array_max_size(), "too big for a single object");
517
518 const size_t payload_size = words - filler_array_hdr_size();
519 const size_t len = payload_size * HeapWordSize / sizeof(jint);
520 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
521
522 // Set the length first for concurrent GC.
523 ((arrayOop)start)->set_length((int)len);
524 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
525 DEBUG_ONLY(zap_filler_array(start, words, zap);)
526 }
527
528 void
529 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
530 {
531 assert(words <= filler_array_max_size(), "too big for a single object");
532
533 if (words >= filler_array_min_size()) {
534 fill_with_array(start, words, zap);
535 } else if (words > 0) {
536 assert(words == min_fill_size(), "unaligned size");
537 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
538 }
539 }
540
541 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
542 {
543 DEBUG_ONLY(fill_args_check(start, words);)
544 HandleMark hm; // Free handles before leaving.
545 fill_with_object_impl(start, words, zap);
546 }
547
548 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
549 {
550 DEBUG_ONLY(fill_args_check(start, words);)
551 HandleMark hm; // Free handles before leaving.
552
553 // Multiple objects may be required depending on the filler array maximum size. Fill
554 // the range up to that with objects that are filler_array_max_size sized. The
555 // remainder is filled with a single object.
556 const size_t min = min_fill_size();
557 const size_t max = filler_array_max_size();
558 while (words > max) {
559 const size_t cur = (words - max) >= min ? max : max - min;
560 fill_with_array(start, cur, zap);
561 start += cur;
562 words -= cur;
563 }
564
565 fill_with_object_impl(start, words, zap);
566 }
567
568 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
569 guarantee(false, "thread-local allocation buffers not supported");
570 return NULL;
571 }
572
573 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
574 // The second disjunct in the assertion below makes a concession
575 // for the start-up verification done while the VM is being
576 // created. Callers be careful that you know that mutators
577 // aren't going to interfere -- for instance, this is permissible
578 // if we are still single-threaded and have either not yet
579 // started allocating (nothing much to verify) or we have
580 // started allocating but are now a full-fledged JavaThread
581 // (and have thus made our TLAB's) available for filling.
582 assert(SafepointSynchronize::is_at_safepoint() ||
583 !is_init_completed(),
584 "Should only be called at a safepoint or at start-up"
585 " otherwise concurrent mutator activity may make heap "
586 " unparsable again");
587 const bool use_tlab = UseTLAB;
588 const bool deferred = _defer_initial_card_mark;
589 // The main thread starts allocating via a TLAB even before it
590 // has added itself to the threads list at vm boot-up.
591 assert(!use_tlab || Threads::first() != NULL,
592 "Attempt to fill tlabs before main thread has been added"
593 " to threads list is doomed to failure!");
594 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
595 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
596 #if defined(COMPILER2) || INCLUDE_JVMCI
597 // The deferred store barriers must all have been flushed to the
598 // card-table (or other remembered set structure) before GC starts
599 // processing the card-table (or other remembered set).
600 if (deferred) flush_deferred_store_barrier(thread);
601 #else
602 assert(!deferred, "Should be false");
603 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
604 #endif
605 }
606 }
607
608 void CollectedHeap::accumulate_statistics_all_tlabs() {
609 if (UseTLAB) {
610 assert(SafepointSynchronize::is_at_safepoint() ||
611 !is_init_completed(),
612 "should only accumulate statistics on tlabs at safepoint");
613
614 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
615 }
616 }
617
618 void CollectedHeap::resize_all_tlabs() {
619 if (UseTLAB) {
620 assert(SafepointSynchronize::is_at_safepoint() ||
621 !is_init_completed(),
622 "should only resize tlabs at safepoint");
623
624 ThreadLocalAllocBuffer::resize_all_tlabs();
625 }
626 }
627
628 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
629 assert(timer != NULL, "timer is null");
630 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
631 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
632 HeapDumper::dump_heap();
633 }
634
635 LogTarget(Trace, gc, classhisto) lt;
636 if (lt.is_enabled()) {
637 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
638 ResourceMark rm;
639 LogStream ls(lt);
640 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
641 inspector.doit();
642 }
643 }
644
645 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
646 full_gc_dump(timer, true);
647 }
648
649 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
650 full_gc_dump(timer, false);
651 }
652
653 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
654 // It is important to do this in a way such that concurrent readers can't
655 // temporarily think something is in the heap. (Seen this happen in asserts.)
656 _reserved.set_word_size(0);
657 _reserved.set_start(start);
658 _reserved.set_end(end);
659 }