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