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