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::allocate_from_tlab_slow(Klass* klass, Thread* thread, 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 // The tlab could still have space after this sample.
307 thread->tlab().set_back_actual_end();
308
309 // Try to allocate again: it could work now.
310 HeapWord* obj = thread->tlab().allocate(size);
311 if (obj != NULL) {
312 // Object got allocated, sample it now.
313 HeapMonitoring::object_alloc_do_sample(thread,
314 reinterpret_cast<oopDesc*>(obj),
315 size);
316 thread->tlab().pick_next_sample();
317 return obj;
318 }
319 }
320 }
321
322 // Retain tlab and allocate object in shared space if
323 // the amount free in the tlab is too large to discard.
324 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
325 thread->tlab().record_slow_allocation(size);
326 return NULL;
327 }
328
329 // Discard tlab and allocate a new one.
330 // To minimize fragmentation, the last TLAB may be smaller than the rest.
331 size_t new_tlab_size = thread->tlab().compute_size(size);
332
333 thread->tlab().clear_before_allocation();
334
335 if (new_tlab_size == 0) {
336 return NULL;
337 }
338
339 // Allocate a new TLAB...
340 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
341 if (obj == NULL) {
342 return NULL;
343 }
344
345 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
346
347 if (ZeroTLAB) {
348 // ..and clear it.
349 Copy::zero_to_words(obj, new_tlab_size);
350 } else {
351 // ...and zap just allocated object.
352 #ifdef ASSERT
353 // Skip mangling the space corresponding to the object header to
354 // ensure that the returned space is not considered parsable by
355 // any concurrent GC thread.
356 size_t hdr_size = oopDesc::header_size();
357 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
358 #endif // ASSERT
359 }
360 thread->tlab().fill(obj, obj + size, new_tlab_size);
361
362 if (HeapMonitoring::enabled()) {
363 if (thread->tlab().should_sample()) {
364 HeapMonitoring::object_alloc_do_sample(thread,
365 reinterpret_cast<oopDesc*>(obj),
366 size);
367 }
368 // Always pick a next sample here.
369 thread->tlab().pick_next_sample();
370 }
371 return obj;
372 }
373
374 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
375 MemRegion deferred = thread->deferred_card_mark();
376 if (!deferred.is_empty()) {
377 assert(_defer_initial_card_mark, "Otherwise should be empty");
378 {
379 // Verify that the storage points to a parsable object in heap
380 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
381 assert(is_in(old_obj), "Not in allocated heap");
382 assert(!can_elide_initializing_store_barrier(old_obj),
383 "Else should have been filtered in new_store_pre_barrier()");
384 assert(old_obj->is_oop(true), "Not an oop");
385 assert(deferred.word_size() == (size_t)(old_obj->size()),
386 "Mismatch: multiple objects?");
387 }
388 BarrierSet* bs = barrier_set();
389 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
390 bs->write_region(deferred);
391 // "Clear" the deferred_card_mark field
392 thread->set_deferred_card_mark(MemRegion());
393 }
394 assert(thread->deferred_card_mark().is_empty(), "invariant");
395 }
396
397 size_t CollectedHeap::max_tlab_size() const {
398 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
399 // This restriction could be removed by enabling filling with multiple arrays.
400 // If we compute that the reasonable way as
401 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
402 // we'll overflow on the multiply, so we do the divide first.
403 // We actually lose a little by dividing first,
404 // but that just makes the TLAB somewhat smaller than the biggest array,
405 // which is fine, since we'll be able to fill that.
406 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
407 sizeof(jint) *
408 ((juint) max_jint / (size_t) HeapWordSize);
409 return align_size_down(max_int_size, MinObjAlignment);
410 }
411
412 // Helper for ReduceInitialCardMarks. For performance,
413 // compiled code may elide card-marks for initializing stores
414 // to a newly allocated object along the fast-path. We
415 // compensate for such elided card-marks as follows:
416 // (a) Generational, non-concurrent collectors, such as
417 // GenCollectedHeap(ParNew,DefNew,Tenured) and
418 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
419 // need the card-mark if and only if the region is
420 // in the old gen, and do not care if the card-mark
421 // succeeds or precedes the initializing stores themselves,
422 // so long as the card-mark is completed before the next
423 // scavenge. For all these cases, we can do a card mark
424 // at the point at which we do a slow path allocation
425 // in the old gen, i.e. in this call.
426 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
427 // in addition that the card-mark for an old gen allocated
428 // object strictly follow any associated initializing stores.
429 // In these cases, the memRegion remembered below is
430 // used to card-mark the entire region either just before the next
431 // slow-path allocation by this thread or just before the next scavenge or
432 // CMS-associated safepoint, whichever of these events happens first.
433 // (The implicit assumption is that the object has been fully
434 // initialized by this point, a fact that we assert when doing the
435 // card-mark.)
436 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
437 // G1 concurrent marking is in progress an SATB (pre-write-)barrier
438 // is used to remember the pre-value of any store. Initializing
439 // stores will not need this barrier, so we need not worry about
440 // compensating for the missing pre-barrier here. Turning now
441 // to the post-barrier, we note that G1 needs a RS update barrier
442 // which simply enqueues a (sequence of) dirty cards which may
443 // optionally be refined by the concurrent update threads. Note
444 // that this barrier need only be applied to a non-young write,
445 // but, like in CMS, because of the presence of concurrent refinement
446 // (much like CMS' precleaning), must strictly follow the oop-store.
447 // Thus, using the same protocol for maintaining the intended
448 // invariants turns out, serendepitously, to be the same for both
449 // G1 and CMS.
450 //
451 // For any future collector, this code should be reexamined with
452 // that specific collector in mind, and the documentation above suitably
453 // extended and updated.
454 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
455 // If a previous card-mark was deferred, flush it now.
456 flush_deferred_store_barrier(thread);
457 if (can_elide_initializing_store_barrier(new_obj) ||
458 new_obj->is_typeArray()) {
459 // Arrays of non-references don't need a pre-barrier.
460 // The deferred_card_mark region should be empty
461 // following the flush above.
462 assert(thread->deferred_card_mark().is_empty(), "Error");
463 } else {
464 MemRegion mr((HeapWord*)new_obj, new_obj->size());
465 assert(!mr.is_empty(), "Error");
466 if (_defer_initial_card_mark) {
467 // Defer the card mark
468 thread->set_deferred_card_mark(mr);
469 } else {
470 // Do the card mark
471 BarrierSet* bs = barrier_set();
472 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
473 bs->write_region(mr);
474 }
475 }
476 return new_obj;
477 }
478
479 size_t CollectedHeap::filler_array_hdr_size() {
480 return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
481 }
482
483 size_t CollectedHeap::filler_array_min_size() {
484 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
485 }
486
487 #ifdef ASSERT
488 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
489 {
490 assert(words >= min_fill_size(), "too small to fill");
491 assert(words % MinObjAlignment == 0, "unaligned size");
492 assert(Universe::heap()->is_in_reserved(start), "not in heap");
493 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
494 }
495
496 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
497 {
498 if (ZapFillerObjects && zap) {
499 Copy::fill_to_words(start + filler_array_hdr_size(),
500 words - filler_array_hdr_size(), 0XDEAFBABE);
501 }
502 }
503 #endif // ASSERT
504
505 void
506 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
507 {
508 assert(words >= filler_array_min_size(), "too small for an array");
509 assert(words <= filler_array_max_size(), "too big for a single object");
510
511 const size_t payload_size = words - filler_array_hdr_size();
512 const size_t len = payload_size * HeapWordSize / sizeof(jint);
513 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
514
515 // Set the length first for concurrent GC.
516 ((arrayOop)start)->set_length((int)len);
517 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
518 DEBUG_ONLY(zap_filler_array(start, words, zap);)
519 }
520
521 void
522 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
523 {
524 assert(words <= filler_array_max_size(), "too big for a single object");
525
526 if (words >= filler_array_min_size()) {
527 fill_with_array(start, words, zap);
528 } else if (words > 0) {
529 assert(words == min_fill_size(), "unaligned size");
530 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
531 }
532 }
533
534 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
535 {
536 DEBUG_ONLY(fill_args_check(start, words);)
537 HandleMark hm; // Free handles before leaving.
538 fill_with_object_impl(start, words, zap);
539 }
540
541 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
542 {
543 DEBUG_ONLY(fill_args_check(start, words);)
544 HandleMark hm; // Free handles before leaving.
545
546 // Multiple objects may be required depending on the filler array maximum size. Fill
547 // the range up to that with objects that are filler_array_max_size sized. The
548 // remainder is filled with a single object.
549 const size_t min = min_fill_size();
550 const size_t max = filler_array_max_size();
551 while (words > max) {
552 const size_t cur = (words - max) >= min ? max : max - min;
553 fill_with_array(start, cur, zap);
554 start += cur;
555 words -= cur;
556 }
557
558 fill_with_object_impl(start, words, zap);
559 }
560
561 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
562 guarantee(false, "thread-local allocation buffers not supported");
563 return NULL;
564 }
565
566 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
567 // The second disjunct in the assertion below makes a concession
568 // for the start-up verification done while the VM is being
569 // created. Callers be careful that you know that mutators
570 // aren't going to interfere -- for instance, this is permissible
571 // if we are still single-threaded and have either not yet
572 // started allocating (nothing much to verify) or we have
573 // started allocating but are now a full-fledged JavaThread
574 // (and have thus made our TLAB's) available for filling.
575 assert(SafepointSynchronize::is_at_safepoint() ||
576 !is_init_completed(),
577 "Should only be called at a safepoint or at start-up"
578 " otherwise concurrent mutator activity may make heap "
579 " unparsable again");
580 const bool use_tlab = UseTLAB;
581 const bool deferred = _defer_initial_card_mark;
582 // The main thread starts allocating via a TLAB even before it
583 // has added itself to the threads list at vm boot-up.
584 assert(!use_tlab || Threads::first() != NULL,
585 "Attempt to fill tlabs before main thread has been added"
586 " to threads list is doomed to failure!");
587 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
588 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
589 #if defined(COMPILER2) || INCLUDE_JVMCI
590 // The deferred store barriers must all have been flushed to the
591 // card-table (or other remembered set structure) before GC starts
592 // processing the card-table (or other remembered set).
593 if (deferred) flush_deferred_store_barrier(thread);
594 #else
595 assert(!deferred, "Should be false");
596 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
597 #endif
598 }
599 }
600
601 void CollectedHeap::accumulate_statistics_all_tlabs() {
602 if (UseTLAB) {
603 assert(SafepointSynchronize::is_at_safepoint() ||
604 !is_init_completed(),
605 "should only accumulate statistics on tlabs at safepoint");
606
607 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
608 }
609 }
610
611 void CollectedHeap::resize_all_tlabs() {
612 if (UseTLAB) {
613 assert(SafepointSynchronize::is_at_safepoint() ||
614 !is_init_completed(),
615 "should only resize tlabs at safepoint");
616
617 ThreadLocalAllocBuffer::resize_all_tlabs();
618 }
619 }
620
621 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
622 assert(timer != NULL, "timer is null");
623 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
624 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
625 HeapDumper::dump_heap();
626 }
627
628 Log(gc, classhisto) log;
629 if (log.is_trace()) {
630 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
631 ResourceMark rm;
632 VM_GC_HeapInspection inspector(log.trace_stream(), false /* ! full gc */);
633 inspector.doit();
634 }
635 }
636
637 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
638 full_gc_dump(timer, true);
639 }
640
641 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
642 full_gc_dump(timer, false);
643 }
644
645 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
646 // It is important to do this in a way such that concurrent readers can't
647 // temporarily think something is in the heap. (Seen this happen in asserts.)
648 _reserved.set_word_size(0);
649 _reserved.set_start(start);
650 _reserved.set_end(end);
651 }