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 "runtime/threadSMR.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::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
140 const GCHeapSummary& heap_summary = create_heap_summary();
141 gc_tracer->report_gc_heap_summary(when, heap_summary);
142
143 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
144 gc_tracer->report_metaspace_summary(when, metaspace_summary);
145 }
146
147 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
148 trace_heap(GCWhen::BeforeGC, gc_tracer);
149 }
150
151 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
152 trace_heap(GCWhen::AfterGC, gc_tracer);
153 }
154
155 // WhiteBox API support for concurrent collectors. These are the
156 // default implementations, for collectors which don't support this
157 // feature.
158 bool CollectedHeap::supports_concurrent_phase_control() const {
159 return false;
160 }
161
162 const char* const* CollectedHeap::concurrent_phases() const {
163 static const char* const result[] = { NULL };
164 return result;
165 }
166
167 bool CollectedHeap::request_concurrent_phase(const char* phase) {
168 return false;
169 }
170
171 // Memory state functions.
172
173
174 CollectedHeap::CollectedHeap() :
175 _barrier_set(NULL),
176 _is_gc_active(false),
177 _total_collections(0),
178 _total_full_collections(0),
179 _gc_cause(GCCause::_no_gc),
180 _gc_lastcause(GCCause::_no_gc),
181 _defer_initial_card_mark(false) // strengthened by subclass in pre_initialize() below.
182 {
183 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
184 const size_t elements_per_word = HeapWordSize / sizeof(jint);
185 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
186 max_len / elements_per_word);
187
188 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
189 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
190
191 if (UsePerfData) {
192 EXCEPTION_MARK;
193
194 // create the gc cause jvmstat counters
195 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
196 80, GCCause::to_string(_gc_cause), CHECK);
197
198 _perf_gc_lastcause =
199 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
200 80, GCCause::to_string(_gc_lastcause), CHECK);
201 }
202
203 // Create the ring log
204 if (LogEvents) {
205 _gc_heap_log = new GCHeapLog();
206 } else {
207 _gc_heap_log = NULL;
208 }
209 }
210
211 // This interface assumes that it's being called by the
212 // vm thread. It collects the heap assuming that the
213 // heap lock is already held and that we are executing in
214 // the context of the vm thread.
215 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
216 assert(Thread::current()->is_VM_thread(), "Precondition#1");
217 assert(Heap_lock->is_locked(), "Precondition#2");
218 GCCauseSetter gcs(this, cause);
219 switch (cause) {
220 case GCCause::_heap_inspection:
221 case GCCause::_heap_dump:
222 case GCCause::_metadata_GC_threshold : {
223 HandleMark hm;
224 do_full_collection(false); // don't clear all soft refs
225 break;
226 }
227 case GCCause::_metadata_GC_clear_soft_refs: {
228 HandleMark hm;
229 do_full_collection(true); // do clear all soft refs
230 break;
231 }
232 default:
233 ShouldNotReachHere(); // Unexpected use of this function
234 }
235 }
236
237 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
238 _barrier_set = barrier_set;
239 BarrierSet::set_bs(barrier_set);
240 }
241
242 void CollectedHeap::pre_initialize() {
243 // Used for ReduceInitialCardMarks (when COMPILER2 is used);
244 // otherwise remains unused.
245 #if COMPILER2_OR_JVMCI
246 _defer_initial_card_mark = is_server_compilation_mode_vm() && ReduceInitialCardMarks && can_elide_tlab_store_barriers()
247 && (DeferInitialCardMark || card_mark_must_follow_store());
248 #else
249 assert(_defer_initial_card_mark == false, "Who would set it?");
250 #endif
251 }
252
253 #ifndef PRODUCT
254 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
255 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
256 for (size_t slot = 0; slot < size; slot += 1) {
257 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
258 "Found badHeapWordValue in post-allocation check");
259 }
260 }
261 }
262
263 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
264 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
265 for (size_t slot = 0; slot < size; slot += 1) {
266 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
267 "Found non badHeapWordValue in pre-allocation check");
268 }
269 }
270 }
271 #endif // PRODUCT
272
273 #ifdef ASSERT
274 void CollectedHeap::check_for_valid_allocation_state() {
275 Thread *thread = Thread::current();
276 // How to choose between a pending exception and a potential
277 // OutOfMemoryError? Don't allow pending exceptions.
278 // This is a VM policy failure, so how do we exhaustively test it?
279 assert(!thread->has_pending_exception(),
280 "shouldn't be allocating with pending exception");
281 if (StrictSafepointChecks) {
282 assert(thread->allow_allocation(),
283 "Allocation done by thread for which allocation is blocked "
284 "by No_Allocation_Verifier!");
285 // Allocation of an oop can always invoke a safepoint,
286 // hence, the true argument
287 thread->check_for_valid_safepoint_state(true);
288 }
289 }
290 #endif
291
292 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
293
294 // Retain tlab and allocate object in shared space if
295 // the amount free in the tlab is too large to discard.
296 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
297 thread->tlab().record_slow_allocation(size);
298 return NULL;
299 }
300
301 // Discard tlab and allocate a new one.
302 // To minimize fragmentation, the last TLAB may be smaller than the rest.
303 size_t new_tlab_size = thread->tlab().compute_size(size);
304
305 thread->tlab().clear_before_allocation();
306
307 if (new_tlab_size == 0) {
308 return NULL;
309 }
310
311 // Allocate a new TLAB...
312 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
313 if (obj == NULL) {
314 return NULL;
315 }
316
317 AllocTracer::send_allocation_in_new_tlab(klass, obj, new_tlab_size * HeapWordSize, size * HeapWordSize, thread);
318
319 if (ZeroTLAB) {
320 // ..and clear it.
321 Copy::zero_to_words(obj, new_tlab_size);
322 } else {
323 // ...and zap just allocated object.
324 #ifdef ASSERT
325 // Skip mangling the space corresponding to the object header to
326 // ensure that the returned space is not considered parsable by
327 // any concurrent GC thread.
328 size_t hdr_size = oopDesc::header_size();
329 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
330 #endif // ASSERT
331 }
332 thread->tlab().fill(obj, obj + size, new_tlab_size);
333 return obj;
334 }
335
336 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
337 MemRegion deferred = thread->deferred_card_mark();
338 if (!deferred.is_empty()) {
339 assert(_defer_initial_card_mark, "Otherwise should be empty");
340 {
341 // Verify that the storage points to a parsable object in heap
342 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
343 assert(is_in(old_obj), "Not in allocated heap");
344 assert(!can_elide_initializing_store_barrier(old_obj),
345 "Else should have been filtered in new_store_pre_barrier()");
346 assert(oopDesc::is_oop(old_obj, true), "Not an oop");
347 assert(deferred.word_size() == (size_t)(old_obj->size()),
348 "Mismatch: multiple objects?");
349 }
350 BarrierSet* bs = barrier_set();
351 bs->write_region(deferred);
352 // "Clear" the deferred_card_mark field
353 thread->set_deferred_card_mark(MemRegion());
354 }
355 assert(thread->deferred_card_mark().is_empty(), "invariant");
356 }
357
358 size_t CollectedHeap::max_tlab_size() const {
359 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
360 // This restriction could be removed by enabling filling with multiple arrays.
361 // If we compute that the reasonable way as
362 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
363 // we'll overflow on the multiply, so we do the divide first.
364 // We actually lose a little by dividing first,
365 // but that just makes the TLAB somewhat smaller than the biggest array,
366 // which is fine, since we'll be able to fill that.
367 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
368 sizeof(jint) *
369 ((juint) max_jint / (size_t) HeapWordSize);
370 return align_down(max_int_size, MinObjAlignment);
371 }
372
373 // Helper for ReduceInitialCardMarks. For performance,
374 // compiled code may elide card-marks for initializing stores
375 // to a newly allocated object along the fast-path. We
376 // compensate for such elided card-marks as follows:
377 // (a) Generational, non-concurrent collectors, such as
378 // GenCollectedHeap(ParNew,DefNew,Tenured) and
379 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
380 // need the card-mark if and only if the region is
381 // in the old gen, and do not care if the card-mark
382 // succeeds or precedes the initializing stores themselves,
383 // so long as the card-mark is completed before the next
384 // scavenge. For all these cases, we can do a card mark
385 // at the point at which we do a slow path allocation
386 // in the old gen, i.e. in this call.
387 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
388 // in addition that the card-mark for an old gen allocated
389 // object strictly follow any associated initializing stores.
390 // In these cases, the memRegion remembered below is
391 // used to card-mark the entire region either just before the next
392 // slow-path allocation by this thread or just before the next scavenge or
393 // CMS-associated safepoint, whichever of these events happens first.
394 // (The implicit assumption is that the object has been fully
395 // initialized by this point, a fact that we assert when doing the
396 // card-mark.)
397 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
398 // G1 concurrent marking is in progress an SATB (pre-write-)barrier
399 // is used to remember the pre-value of any store. Initializing
400 // stores will not need this barrier, so we need not worry about
401 // compensating for the missing pre-barrier here. Turning now
402 // to the post-barrier, we note that G1 needs a RS update barrier
403 // which simply enqueues a (sequence of) dirty cards which may
404 // optionally be refined by the concurrent update threads. Note
405 // that this barrier need only be applied to a non-young write,
406 // but, like in CMS, because of the presence of concurrent refinement
407 // (much like CMS' precleaning), must strictly follow the oop-store.
408 // Thus, using the same protocol for maintaining the intended
409 // invariants turns out, serendepitously, to be the same for both
410 // G1 and CMS.
411 //
412 // For any future collector, this code should be reexamined with
413 // that specific collector in mind, and the documentation above suitably
414 // extended and updated.
415 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
416 // If a previous card-mark was deferred, flush it now.
417 flush_deferred_store_barrier(thread);
418 if (can_elide_initializing_store_barrier(new_obj) ||
419 new_obj->is_typeArray()) {
420 // Arrays of non-references don't need a pre-barrier.
421 // The deferred_card_mark region should be empty
422 // following the flush above.
423 assert(thread->deferred_card_mark().is_empty(), "Error");
424 } else {
425 MemRegion mr((HeapWord*)new_obj, new_obj->size());
426 assert(!mr.is_empty(), "Error");
427 if (_defer_initial_card_mark) {
428 // Defer the card mark
429 thread->set_deferred_card_mark(mr);
430 } else {
431 // Do the card mark
432 BarrierSet* bs = barrier_set();
433 bs->write_region(mr);
434 }
435 }
436 return new_obj;
437 }
438
439 size_t CollectedHeap::filler_array_hdr_size() {
440 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
441 }
442
443 size_t CollectedHeap::filler_array_min_size() {
444 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
445 }
446
447 #ifdef ASSERT
448 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
449 {
450 assert(words >= min_fill_size(), "too small to fill");
451 assert(is_object_aligned(words), "unaligned size");
452 assert(Universe::heap()->is_in_reserved(start), "not in heap");
453 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
454 }
455
456 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
457 {
458 if (ZapFillerObjects && zap) {
459 Copy::fill_to_words(start + filler_array_hdr_size(),
460 words - filler_array_hdr_size(), 0XDEAFBABE);
461 }
462 }
463 #endif // ASSERT
464
465 void
466 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
467 {
468 assert(words >= filler_array_min_size(), "too small for an array");
469 assert(words <= filler_array_max_size(), "too big for a single object");
470
471 const size_t payload_size = words - filler_array_hdr_size();
472 const size_t len = payload_size * HeapWordSize / sizeof(jint);
473 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
474
475 // Set the length first for concurrent GC.
476 ((arrayOop)start)->set_length((int)len);
477 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
478 DEBUG_ONLY(zap_filler_array(start, words, zap);)
479 }
480
481 void
482 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
483 {
484 assert(words <= filler_array_max_size(), "too big for a single object");
485
486 if (words >= filler_array_min_size()) {
487 fill_with_array(start, words, zap);
488 } else if (words > 0) {
489 assert(words == min_fill_size(), "unaligned size");
490 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
491 }
492 }
493
494 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
495 {
496 DEBUG_ONLY(fill_args_check(start, words);)
497 HandleMark hm; // Free handles before leaving.
498 fill_with_object_impl(start, words, zap);
499 }
500
501 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
502 {
503 DEBUG_ONLY(fill_args_check(start, words);)
504 HandleMark hm; // Free handles before leaving.
505
506 // Multiple objects may be required depending on the filler array maximum size. Fill
507 // the range up to that with objects that are filler_array_max_size sized. The
508 // remainder is filled with a single object.
509 const size_t min = min_fill_size();
510 const size_t max = filler_array_max_size();
511 while (words > max) {
512 const size_t cur = (words - max) >= min ? max : max - min;
513 fill_with_array(start, cur, zap);
514 start += cur;
515 words -= cur;
516 }
517
518 fill_with_object_impl(start, words, zap);
519 }
520
521 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
522 guarantee(false, "thread-local allocation buffers not supported");
523 return NULL;
524 }
525
526 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
527 // The second disjunct in the assertion below makes a concession
528 // for the start-up verification done while the VM is being
529 // created. Callers be careful that you know that mutators
530 // aren't going to interfere -- for instance, this is permissible
531 // if we are still single-threaded and have either not yet
532 // started allocating (nothing much to verify) or we have
533 // started allocating but are now a full-fledged JavaThread
534 // (and have thus made our TLAB's) available for filling.
535 assert(SafepointSynchronize::is_at_safepoint() ||
536 !is_init_completed(),
537 "Should only be called at a safepoint or at start-up"
538 " otherwise concurrent mutator activity may make heap "
539 " unparsable again");
540 const bool use_tlab = UseTLAB;
541 const bool deferred = _defer_initial_card_mark;
542 // The main thread starts allocating via a TLAB even before it
543 // has added itself to the threads list at vm boot-up.
544 JavaThreadIteratorWithHandle jtiwh;
545 assert(!use_tlab || jtiwh.length() > 0,
546 "Attempt to fill tlabs before main thread has been added"
547 " to threads list is doomed to failure!");
548 for (; JavaThread *thread = jtiwh.next(); ) {
549 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
550 #if COMPILER2_OR_JVMCI
551 // The deferred store barriers must all have been flushed to the
552 // card-table (or other remembered set structure) before GC starts
553 // processing the card-table (or other remembered set).
554 if (deferred) flush_deferred_store_barrier(thread);
555 #else
556 assert(!deferred, "Should be false");
557 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
558 #endif
559 }
560 }
561
562 void CollectedHeap::accumulate_statistics_all_tlabs() {
563 if (UseTLAB) {
564 assert(SafepointSynchronize::is_at_safepoint() ||
565 !is_init_completed(),
566 "should only accumulate statistics on tlabs at safepoint");
567
568 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
569 }
570 }
571
572 void CollectedHeap::resize_all_tlabs() {
573 if (UseTLAB) {
574 assert(SafepointSynchronize::is_at_safepoint() ||
575 !is_init_completed(),
576 "should only resize tlabs at safepoint");
577
578 ThreadLocalAllocBuffer::resize_all_tlabs();
579 }
580 }
581
582 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
583 assert(timer != NULL, "timer is null");
584 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
585 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
586 HeapDumper::dump_heap();
587 }
588
589 LogTarget(Trace, gc, classhisto) lt;
590 if (lt.is_enabled()) {
591 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
592 ResourceMark rm;
593 LogStream ls(lt);
594 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
595 inspector.doit();
596 }
597 }
598
599 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
600 full_gc_dump(timer, true);
601 }
602
603 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
604 full_gc_dump(timer, false);
605 }
606
607 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
608 // It is important to do this in a way such that concurrent readers can't
609 // temporarily think something is in the heap. (Seen this happen in asserts.)
610 _reserved.set_word_size(0);
611 _reserved.set_start(start);
612 _reserved.set_end(end);
613 }
614
615 void CollectedHeap::post_initialize() {
616 initialize_serviceability();
617 }