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 HeapWord *end = thread->tlab().end();
308 thread->tlab().set_back_actual_end();
309
310 // If we don't have an object yet, try to allocate it.
311 if (obj == NULL) {
312 // The tlab could still have space after this sample.
313 obj = thread->tlab().allocate(size);
314 }
315
316 // Is the object allocated now?
317 // If not, this means we have to wait till a new TLAB, let the subsequent
318 // call to handle_heap_sampling pick the next sample.
319 if (obj != NULL) {
320 // Object is allocated, sample it now.
321 HeapMonitoring::object_alloc_do_sample(thread,
322 reinterpret_cast<oopDesc*>(obj),
323 size * HeapWordSize);
324 // Pick a next sample in this case, we allocated right.
325 thread->tlab().pick_next_sample(thread->tlab().top() - end);
326 }
327 }
328 }
329
330 return obj;
331 }
332
333 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
334 HeapWord* obj = handle_heap_sampling(thread, NULL, size);
335 bool should_sample = thread->tlab().should_sample();
336
337 if (obj != NULL) {
338 return obj;
339 }
340
341 // Retain tlab and allocate object in shared space if
342 // the amount free in the tlab is too large to discard.
343 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
344 thread->tlab().record_slow_allocation(size);
345 return NULL;
346 }
347
348 // Discard tlab and allocate a new one.
349 // To minimize fragmentation, the last TLAB may be smaller than the rest.
350 size_t new_tlab_size = thread->tlab().compute_size(size);
351
352 thread->tlab().clear_before_allocation();
353
354 if (new_tlab_size == 0) {
355 return NULL;
356 }
357
358 // Allocate a new TLAB...
359 obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
360 if (obj == NULL) {
361 return NULL;
362 }
363
364 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
365
366 if (ZeroTLAB) {
367 // ..and clear it.
368 Copy::zero_to_words(obj, new_tlab_size);
369 } else {
370 // ...and zap just allocated object.
371 #ifdef ASSERT
372 // Skip mangling the space corresponding to the object header to
373 // ensure that the returned space is not considered parsable by
374 // any concurrent GC thread.
375 size_t hdr_size = oopDesc::header_size();
376 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
377 #endif // ASSERT
378 }
379 thread->tlab().fill(obj, obj + size, new_tlab_size);
380
381 if (should_sample) {
382 return handle_heap_sampling(thread, obj, size);
383 } else {
384 return obj;
385 }
386 }
387
388 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
389 MemRegion deferred = thread->deferred_card_mark();
390 if (!deferred.is_empty()) {
391 assert(_defer_initial_card_mark, "Otherwise should be empty");
392 {
393 // Verify that the storage points to a parsable object in heap
394 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
395 assert(is_in(old_obj), "Not in allocated heap");
396 assert(!can_elide_initializing_store_barrier(old_obj),
397 "Else should have been filtered in new_store_pre_barrier()");
398 assert(oopDesc::is_oop(old_obj, true), "Not an oop");
399 assert(deferred.word_size() == (size_t)(old_obj->size()),
400 "Mismatch: multiple objects?");
401 }
402 BarrierSet* bs = barrier_set();
403 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
404 bs->write_region(deferred);
405 // "Clear" the deferred_card_mark field
406 thread->set_deferred_card_mark(MemRegion());
407 }
408 assert(thread->deferred_card_mark().is_empty(), "invariant");
409 }
410
411 size_t CollectedHeap::max_tlab_size() const {
412 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
413 // This restriction could be removed by enabling filling with multiple arrays.
414 // If we compute that the reasonable way as
415 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
416 // we'll overflow on the multiply, so we do the divide first.
417 // We actually lose a little by dividing first,
418 // but that just makes the TLAB somewhat smaller than the biggest array,
419 // which is fine, since we'll be able to fill that.
420 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
421 sizeof(jint) *
422 ((juint) max_jint / (size_t) HeapWordSize);
423 return align_down(max_int_size, MinObjAlignment);
424 }
425
426 // Helper for ReduceInitialCardMarks. For performance,
427 // compiled code may elide card-marks for initializing stores
428 // to a newly allocated object along the fast-path. We
429 // compensate for such elided card-marks as follows:
430 // (a) Generational, non-concurrent collectors, such as
431 // GenCollectedHeap(ParNew,DefNew,Tenured) and
432 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
433 // need the card-mark if and only if the region is
434 // in the old gen, and do not care if the card-mark
435 // succeeds or precedes the initializing stores themselves,
436 // so long as the card-mark is completed before the next
437 // scavenge. For all these cases, we can do a card mark
438 // at the point at which we do a slow path allocation
439 // in the old gen, i.e. in this call.
440 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
441 // in addition that the card-mark for an old gen allocated
442 // object strictly follow any associated initializing stores.
443 // In these cases, the memRegion remembered below is
444 // used to card-mark the entire region either just before the next
445 // slow-path allocation by this thread or just before the next scavenge or
446 // CMS-associated safepoint, whichever of these events happens first.
447 // (The implicit assumption is that the object has been fully
448 // initialized by this point, a fact that we assert when doing the
449 // card-mark.)
450 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
451 // G1 concurrent marking is in progress an SATB (pre-write-)barrier
452 // is used to remember the pre-value of any store. Initializing
453 // stores will not need this barrier, so we need not worry about
454 // compensating for the missing pre-barrier here. Turning now
455 // to the post-barrier, we note that G1 needs a RS update barrier
456 // which simply enqueues a (sequence of) dirty cards which may
457 // optionally be refined by the concurrent update threads. Note
458 // that this barrier need only be applied to a non-young write,
459 // but, like in CMS, because of the presence of concurrent refinement
460 // (much like CMS' precleaning), must strictly follow the oop-store.
461 // Thus, using the same protocol for maintaining the intended
462 // invariants turns out, serendepitously, to be the same for both
463 // G1 and CMS.
464 //
465 // For any future collector, this code should be reexamined with
466 // that specific collector in mind, and the documentation above suitably
467 // extended and updated.
468 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
469 // If a previous card-mark was deferred, flush it now.
470 flush_deferred_store_barrier(thread);
471 if (can_elide_initializing_store_barrier(new_obj) ||
472 new_obj->is_typeArray()) {
473 // Arrays of non-references don't need a pre-barrier.
474 // The deferred_card_mark region should be empty
475 // following the flush above.
476 assert(thread->deferred_card_mark().is_empty(), "Error");
477 } else {
478 MemRegion mr((HeapWord*)new_obj, new_obj->size());
479 assert(!mr.is_empty(), "Error");
480 if (_defer_initial_card_mark) {
481 // Defer the card mark
482 thread->set_deferred_card_mark(mr);
483 } else {
484 // Do the card mark
485 BarrierSet* bs = barrier_set();
486 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
487 bs->write_region(mr);
488 }
489 }
490 return new_obj;
491 }
492
493 size_t CollectedHeap::filler_array_hdr_size() {
494 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
495 }
496
497 size_t CollectedHeap::filler_array_min_size() {
498 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
499 }
500
501 #ifdef ASSERT
502 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
503 {
504 assert(words >= min_fill_size(), "too small to fill");
505 assert(is_object_aligned(words), "unaligned size");
506 assert(Universe::heap()->is_in_reserved(start), "not in heap");
507 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
508 }
509
510 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
511 {
512 if (ZapFillerObjects && zap) {
513 Copy::fill_to_words(start + filler_array_hdr_size(),
514 words - filler_array_hdr_size(), 0XDEAFBABE);
515 }
516 }
517 #endif // ASSERT
518
519 void
520 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
521 {
522 assert(words >= filler_array_min_size(), "too small for an array");
523 assert(words <= filler_array_max_size(), "too big for a single object");
524
525 const size_t payload_size = words - filler_array_hdr_size();
526 const size_t len = payload_size * HeapWordSize / sizeof(jint);
527 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
528
529 // Set the length first for concurrent GC.
530 ((arrayOop)start)->set_length((int)len);
531 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
532 DEBUG_ONLY(zap_filler_array(start, words, zap);)
533 }
534
535 void
536 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
537 {
538 assert(words <= filler_array_max_size(), "too big for a single object");
539
540 if (words >= filler_array_min_size()) {
541 fill_with_array(start, words, zap);
542 } else if (words > 0) {
543 assert(words == min_fill_size(), "unaligned size");
544 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
545 }
546 }
547
548 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
549 {
550 DEBUG_ONLY(fill_args_check(start, words);)
551 HandleMark hm; // Free handles before leaving.
552 fill_with_object_impl(start, words, zap);
553 }
554
555 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
556 {
557 DEBUG_ONLY(fill_args_check(start, words);)
558 HandleMark hm; // Free handles before leaving.
559
560 // Multiple objects may be required depending on the filler array maximum size. Fill
561 // the range up to that with objects that are filler_array_max_size sized. The
562 // remainder is filled with a single object.
563 const size_t min = min_fill_size();
564 const size_t max = filler_array_max_size();
565 while (words > max) {
566 const size_t cur = (words - max) >= min ? max : max - min;
567 fill_with_array(start, cur, zap);
568 start += cur;
569 words -= cur;
570 }
571
572 fill_with_object_impl(start, words, zap);
573 }
574
575 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
576 guarantee(false, "thread-local allocation buffers not supported");
577 return NULL;
578 }
579
580 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
581 // The second disjunct in the assertion below makes a concession
582 // for the start-up verification done while the VM is being
583 // created. Callers be careful that you know that mutators
584 // aren't going to interfere -- for instance, this is permissible
585 // if we are still single-threaded and have either not yet
586 // started allocating (nothing much to verify) or we have
587 // started allocating but are now a full-fledged JavaThread
588 // (and have thus made our TLAB's) available for filling.
589 assert(SafepointSynchronize::is_at_safepoint() ||
590 !is_init_completed(),
591 "Should only be called at a safepoint or at start-up"
592 " otherwise concurrent mutator activity may make heap "
593 " unparsable again");
594 const bool use_tlab = UseTLAB;
595 const bool deferred = _defer_initial_card_mark;
596 // The main thread starts allocating via a TLAB even before it
597 // has added itself to the threads list at vm boot-up.
598 assert(!use_tlab || Threads::first() != NULL,
599 "Attempt to fill tlabs before main thread has been added"
600 " to threads list is doomed to failure!");
601 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
602 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
603 #if defined(COMPILER2) || INCLUDE_JVMCI
604 // The deferred store barriers must all have been flushed to the
605 // card-table (or other remembered set structure) before GC starts
606 // processing the card-table (or other remembered set).
607 if (deferred) flush_deferred_store_barrier(thread);
608 #else
609 assert(!deferred, "Should be false");
610 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
611 #endif
612 }
613 }
614
615 void CollectedHeap::accumulate_statistics_all_tlabs() {
616 if (UseTLAB) {
617 assert(SafepointSynchronize::is_at_safepoint() ||
618 !is_init_completed(),
619 "should only accumulate statistics on tlabs at safepoint");
620
621 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
622 }
623 }
624
625 void CollectedHeap::resize_all_tlabs() {
626 if (UseTLAB) {
627 assert(SafepointSynchronize::is_at_safepoint() ||
628 !is_init_completed(),
629 "should only resize tlabs at safepoint");
630
631 ThreadLocalAllocBuffer::resize_all_tlabs();
632 }
633 }
634
635 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
636 assert(timer != NULL, "timer is null");
637 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
638 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
639 HeapDumper::dump_heap();
640 }
641
642 LogTarget(Trace, gc, classhisto) lt;
643 if (lt.is_enabled()) {
644 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
645 ResourceMark rm;
646 LogStream ls(lt);
647 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
648 inspector.doit();
649 }
650 }
651
652 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
653 full_gc_dump(timer, true);
654 }
655
656 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
657 full_gc_dump(timer, false);
658 }
659
660 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
661 // It is important to do this in a way such that concurrent readers can't
662 // temporarily think something is in the heap. (Seen this happen in asserts.)
663 _reserved.set_word_size(0);
664 _reserved.set_start(start);
665 _reserved.set_end(end);
666 }