1 /*
2 * Copyright (c) 2001, 2015, 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.hpp"
34 #include "gc/shared/gcWhen.hpp"
35 #include "gc/shared/vmGCOperations.hpp"
36 #include "memory/metaspace.hpp"
37 #include "oops/instanceMirrorKlass.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/init.hpp"
40 #include "runtime/thread.inline.hpp"
41 #include "services/heapDumper.hpp"
42
43
44 #ifdef ASSERT
45 int CollectedHeap::_fire_out_of_memory_count = 0;
46 #endif
47
48 size_t CollectedHeap::_filler_array_max_size = 0;
49
50 template <>
51 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
52 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
53 st->print_raw(m);
54 }
55
56 void GCHeapLog::log_heap(bool before) {
57 if (!should_log()) {
58 return;
59 }
60
61 double timestamp = fetch_timestamp();
62 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
63 int index = compute_log_index();
64 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
65 _records[index].timestamp = timestamp;
66 _records[index].data.is_before = before;
67 stringStream st(_records[index].data.buffer(), _records[index].data.size());
68 if (before) {
69 Universe::print_heap_before_gc(&st, true);
70 } else {
71 Universe::print_heap_after_gc(&st, true);
72 }
73 }
74
75 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
76 size_t capacity_in_words = capacity() / HeapWordSize;
77
78 return VirtualSpaceSummary(
79 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
80 }
81
82 GCHeapSummary CollectedHeap::create_heap_summary() {
83 VirtualSpaceSummary heap_space = create_heap_space_summary();
84 return GCHeapSummary(heap_space, used());
85 }
86
87 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
88 const MetaspaceSizes meta_space(
89 MetaspaceAux::committed_bytes(),
90 MetaspaceAux::used_bytes(),
91 MetaspaceAux::reserved_bytes());
92 const MetaspaceSizes data_space(
93 MetaspaceAux::committed_bytes(Metaspace::NonClassType),
94 MetaspaceAux::used_bytes(Metaspace::NonClassType),
95 MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
96 const MetaspaceSizes class_space(
97 MetaspaceAux::committed_bytes(Metaspace::ClassType),
98 MetaspaceAux::used_bytes(Metaspace::ClassType),
99 MetaspaceAux::reserved_bytes(Metaspace::ClassType));
100
101 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
102 MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
103 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
104 MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
105
106 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
107 ms_chunk_free_list_summary, class_chunk_free_list_summary);
108 }
109
110 void CollectedHeap::print_heap_before_gc() {
111 if (PrintHeapAtGC) {
112 Universe::print_heap_before_gc();
113 }
114 if (_gc_heap_log != NULL) {
115 _gc_heap_log->log_heap_before();
116 }
117 }
118
119 void CollectedHeap::print_heap_after_gc() {
120 if (PrintHeapAtGC) {
121 Universe::print_heap_after_gc();
122 }
123 if (_gc_heap_log != NULL) {
124 _gc_heap_log->log_heap_after();
125 }
126 }
127
128 void CollectedHeap::print_on_error(outputStream* st) const {
129 st->print_cr("Heap:");
130 print_extended_on(st);
131 st->cr();
132
133 _barrier_set->print_on(st);
134 }
135
136 void CollectedHeap::register_nmethod(nmethod* nm) {
137 assert_locked_or_safepoint(CodeCache_lock);
138 }
139
140 void CollectedHeap::unregister_nmethod(nmethod* nm) {
141 assert_locked_or_safepoint(CodeCache_lock);
142 }
143
144 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
145 const GCHeapSummary& heap_summary = create_heap_summary();
146 gc_tracer->report_gc_heap_summary(when, heap_summary);
147
148 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
149 gc_tracer->report_metaspace_summary(when, metaspace_summary);
150 }
151
152 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
153 trace_heap(GCWhen::BeforeGC, gc_tracer);
154 }
155
156 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
157 trace_heap(GCWhen::AfterGC, gc_tracer);
158 }
159
160 // Memory state functions.
161
162
163 CollectedHeap::CollectedHeap() {
164 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
165 const size_t elements_per_word = HeapWordSize / sizeof(jint);
166 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
167 max_len / elements_per_word);
168
169 _barrier_set = NULL;
170 _is_gc_active = false;
171 _total_collections = _total_full_collections = 0;
172 _gc_cause = _gc_lastcause = GCCause::_no_gc;
173 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
174 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
175
176 if (UsePerfData) {
177 EXCEPTION_MARK;
178
179 // create the gc cause jvmstat counters
180 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
181 80, GCCause::to_string(_gc_cause), CHECK);
182
183 _perf_gc_lastcause =
184 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
185 80, GCCause::to_string(_gc_lastcause), CHECK);
186 }
187 _defer_initial_card_mark = false; // strengthened by subclass in pre_initialize() below.
188 // Create the ring log
189 if (LogEvents) {
190 _gc_heap_log = new GCHeapLog();
191 } else {
192 _gc_heap_log = NULL;
193 }
194 }
195
196 // This interface assumes that it's being called by the
197 // vm thread. It collects the heap assuming that the
198 // heap lock is already held and that we are executing in
199 // the context of the vm thread.
200 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
201 assert(Thread::current()->is_VM_thread(), "Precondition#1");
202 assert(Heap_lock->is_locked(), "Precondition#2");
203 GCCauseSetter gcs(this, cause);
204 switch (cause) {
205 case GCCause::_heap_inspection:
206 case GCCause::_heap_dump:
207 case GCCause::_metadata_GC_threshold : {
208 HandleMark hm;
209 do_full_collection(false); // don't clear all soft refs
210 break;
211 }
212 case GCCause::_last_ditch_collection: {
213 HandleMark hm;
214 do_full_collection(true); // do clear all soft refs
215 break;
216 }
217 default:
218 ShouldNotReachHere(); // Unexpected use of this function
219 }
220 }
221
222 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
223 _barrier_set = barrier_set;
224 oopDesc::set_bs(_barrier_set);
225 }
226
227 void CollectedHeap::pre_initialize() {
228 // Used for ReduceInitialCardMarks (when COMPILER2 is used);
229 // otherwise remains unused.
230 #ifdef COMPILER2
231 _defer_initial_card_mark = ReduceInitialCardMarks && can_elide_tlab_store_barriers()
232 && (DeferInitialCardMark || card_mark_must_follow_store());
233 #else
234 assert(_defer_initial_card_mark == false, "Who would set it?");
235 #endif
236 }
237
238 #ifndef PRODUCT
239 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
240 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
241 for (size_t slot = 0; slot < size; slot += 1) {
242 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
243 "Found badHeapWordValue in post-allocation check");
244 }
245 }
246 }
247
248 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
249 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
250 for (size_t slot = 0; slot < size; slot += 1) {
251 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
252 "Found non badHeapWordValue in pre-allocation check");
253 }
254 }
255 }
256 #endif // PRODUCT
257
258 #ifdef ASSERT
259 void CollectedHeap::check_for_valid_allocation_state() {
260 Thread *thread = Thread::current();
261 // How to choose between a pending exception and a potential
262 // OutOfMemoryError? Don't allow pending exceptions.
263 // This is a VM policy failure, so how do we exhaustively test it?
264 assert(!thread->has_pending_exception(),
265 "shouldn't be allocating with pending exception");
266 if (StrictSafepointChecks) {
267 assert(thread->allow_allocation(),
268 "Allocation done by thread for which allocation is blocked "
269 "by No_Allocation_Verifier!");
270 // Allocation of an oop can always invoke a safepoint,
271 // hence, the true argument
272 thread->check_for_valid_safepoint_state(true);
273 }
274 }
275 #endif
276
277 HeapWord* CollectedHeap::allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size) {
278
279 // Retain tlab and allocate object in shared space if
280 // the amount free in the tlab is too large to discard.
281 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
282 thread->tlab().record_slow_allocation(size);
283 return NULL;
284 }
285
286 // Discard tlab and allocate a new one.
287 // To minimize fragmentation, the last TLAB may be smaller than the rest.
288 size_t new_tlab_size = thread->tlab().compute_size(size);
289
290 thread->tlab().clear_before_allocation();
291
292 if (new_tlab_size == 0) {
293 return NULL;
294 }
295
296 // Allocate a new TLAB...
297 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
298 if (obj == NULL) {
299 return NULL;
300 }
301
302 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
303
304 if (ZeroTLAB) {
305 // ..and clear it.
306 Copy::zero_to_words(obj, new_tlab_size);
307 } else {
308 // ...and zap just allocated object.
309 #ifdef ASSERT
310 // Skip mangling the space corresponding to the object header to
311 // ensure that the returned space is not considered parsable by
312 // any concurrent GC thread.
313 size_t hdr_size = oopDesc::header_size();
314 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
315 #endif // ASSERT
316 }
317 thread->tlab().fill(obj, obj + size, new_tlab_size);
318 return obj;
319 }
320
321 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
322 MemRegion deferred = thread->deferred_card_mark();
323 if (!deferred.is_empty()) {
324 assert(_defer_initial_card_mark, "Otherwise should be empty");
325 {
326 // Verify that the storage points to a parsable object in heap
327 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
328 assert(is_in(old_obj), "Not in allocated heap");
329 assert(!can_elide_initializing_store_barrier(old_obj),
330 "Else should have been filtered in new_store_pre_barrier()");
331 assert(old_obj->is_oop(true), "Not an oop");
332 assert(deferred.word_size() == (size_t)(old_obj->size()),
333 "Mismatch: multiple objects?");
334 }
335 BarrierSet* bs = barrier_set();
336 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
337 bs->write_region(deferred);
338 // "Clear" the deferred_card_mark field
339 thread->set_deferred_card_mark(MemRegion());
340 }
341 assert(thread->deferred_card_mark().is_empty(), "invariant");
342 }
343
344 size_t CollectedHeap::max_tlab_size() const {
345 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
346 // This restriction could be removed by enabling filling with multiple arrays.
347 // If we compute that the reasonable way as
348 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
349 // we'll overflow on the multiply, so we do the divide first.
350 // We actually lose a little by dividing first,
351 // but that just makes the TLAB somewhat smaller than the biggest array,
352 // which is fine, since we'll be able to fill that.
353 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
354 sizeof(jint) *
355 ((juint) max_jint / (size_t) HeapWordSize);
356 return align_size_down(max_int_size, MinObjAlignment);
357 }
358
359 // Helper for ReduceInitialCardMarks. For performance,
360 // compiled code may elide card-marks for initializing stores
361 // to a newly allocated object along the fast-path. We
362 // compensate for such elided card-marks as follows:
363 // (a) Generational, non-concurrent collectors, such as
364 // GenCollectedHeap(ParNew,DefNew,Tenured) and
365 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
366 // need the card-mark if and only if the region is
367 // in the old gen, and do not care if the card-mark
368 // succeeds or precedes the initializing stores themselves,
369 // so long as the card-mark is completed before the next
370 // scavenge. For all these cases, we can do a card mark
371 // at the point at which we do a slow path allocation
372 // in the old gen, i.e. in this call.
373 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
374 // in addition that the card-mark for an old gen allocated
375 // object strictly follow any associated initializing stores.
376 // In these cases, the memRegion remembered below is
377 // used to card-mark the entire region either just before the next
378 // slow-path allocation by this thread or just before the next scavenge or
379 // CMS-associated safepoint, whichever of these events happens first.
380 // (The implicit assumption is that the object has been fully
381 // initialized by this point, a fact that we assert when doing the
382 // card-mark.)
383 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
384 // G1 concurrent marking is in progress an SATB (pre-write-)barrier is
385 // is used to remember the pre-value of any store. Initializing
386 // stores will not need this barrier, so we need not worry about
387 // compensating for the missing pre-barrier here. Turning now
388 // to the post-barrier, we note that G1 needs a RS update barrier
389 // which simply enqueues a (sequence of) dirty cards which may
390 // optionally be refined by the concurrent update threads. Note
391 // that this barrier need only be applied to a non-young write,
392 // but, like in CMS, because of the presence of concurrent refinement
393 // (much like CMS' precleaning), must strictly follow the oop-store.
394 // Thus, using the same protocol for maintaining the intended
395 // invariants turns out, serendepitously, to be the same for both
396 // G1 and CMS.
397 //
398 // For any future collector, this code should be reexamined with
399 // that specific collector in mind, and the documentation above suitably
400 // extended and updated.
401 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
402 // If a previous card-mark was deferred, flush it now.
403 flush_deferred_store_barrier(thread);
404 if (can_elide_initializing_store_barrier(new_obj)) {
405 // The deferred_card_mark region should be empty
406 // following the flush above.
407 assert(thread->deferred_card_mark().is_empty(), "Error");
408 } else {
409 MemRegion mr((HeapWord*)new_obj, new_obj->size());
410 assert(!mr.is_empty(), "Error");
411 if (_defer_initial_card_mark) {
412 // Defer the card mark
413 thread->set_deferred_card_mark(mr);
414 } else {
415 // Do the card mark
416 BarrierSet* bs = barrier_set();
417 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
418 bs->write_region(mr);
419 }
420 }
421 return new_obj;
422 }
423
424 size_t CollectedHeap::filler_array_hdr_size() {
425 return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
426 }
427
428 size_t CollectedHeap::filler_array_min_size() {
429 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
430 }
431
432 #ifdef ASSERT
433 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
434 {
435 assert(words >= min_fill_size(), "too small to fill");
436 assert(words % MinObjAlignment == 0, "unaligned size");
437 assert(Universe::heap()->is_in_reserved(start), "not in heap");
438 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
439 }
440
441 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
442 {
443 if (ZapFillerObjects && zap) {
444 Copy::fill_to_words(start + filler_array_hdr_size(),
445 words - filler_array_hdr_size(), 0XDEAFBABE);
446 }
447 }
448 #endif // ASSERT
449
450 void
451 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
452 {
453 assert(words >= filler_array_min_size(), "too small for an array");
454 assert(words <= filler_array_max_size(), "too big for a single object");
455
456 const size_t payload_size = words - filler_array_hdr_size();
457 const size_t len = payload_size * HeapWordSize / sizeof(jint);
458 assert((int)len >= 0, err_msg("size too large " SIZE_FORMAT " becomes %d", words, (int)len));
459
460 // Set the length first for concurrent GC.
461 ((arrayOop)start)->set_length((int)len);
462 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
463 DEBUG_ONLY(zap_filler_array(start, words, zap);)
464 }
465
466 void
467 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
468 {
469 assert(words <= filler_array_max_size(), "too big for a single object");
470
471 if (words >= filler_array_min_size()) {
472 fill_with_array(start, words, zap);
473 } else if (words > 0) {
474 assert(words == min_fill_size(), "unaligned size");
475 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
476 }
477 }
478
479 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
480 {
481 DEBUG_ONLY(fill_args_check(start, words);)
482 HandleMark hm; // Free handles before leaving.
483 fill_with_object_impl(start, words, zap);
484 }
485
486 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
487 {
488 DEBUG_ONLY(fill_args_check(start, words);)
489 HandleMark hm; // Free handles before leaving.
490
491 // Multiple objects may be required depending on the filler array maximum size. Fill
492 // the range up to that with objects that are filler_array_max_size sized. The
493 // remainder is filled with a single object.
494 const size_t min = min_fill_size();
495 const size_t max = filler_array_max_size();
496 while (words > max) {
497 const size_t cur = (words - max) >= min ? max : max - min;
498 fill_with_array(start, cur, zap);
499 start += cur;
500 words -= cur;
501 }
502
503 fill_with_object_impl(start, words, zap);
504 }
505
506 void CollectedHeap::post_initialize() {
507 collector_policy()->post_heap_initialize();
508 }
509
510 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
511 guarantee(false, "thread-local allocation buffers not supported");
512 return NULL;
513 }
514
515 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
516 // The second disjunct in the assertion below makes a concession
517 // for the start-up verification done while the VM is being
518 // created. Callers be careful that you know that mutators
519 // aren't going to interfere -- for instance, this is permissible
520 // if we are still single-threaded and have either not yet
521 // started allocating (nothing much to verify) or we have
522 // started allocating but are now a full-fledged JavaThread
523 // (and have thus made our TLAB's) available for filling.
524 assert(SafepointSynchronize::is_at_safepoint() ||
525 !is_init_completed(),
526 "Should only be called at a safepoint or at start-up"
527 " otherwise concurrent mutator activity may make heap "
528 " unparsable again");
529 const bool use_tlab = UseTLAB;
530 const bool deferred = _defer_initial_card_mark;
531 // The main thread starts allocating via a TLAB even before it
532 // has added itself to the threads list at vm boot-up.
533 assert(!use_tlab || Threads::first() != NULL,
534 "Attempt to fill tlabs before main thread has been added"
535 " to threads list is doomed to failure!");
536 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
537 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
538 #ifdef COMPILER2
539 // The deferred store barriers must all have been flushed to the
540 // card-table (or other remembered set structure) before GC starts
541 // processing the card-table (or other remembered set).
542 if (deferred) flush_deferred_store_barrier(thread);
543 #else
544 assert(!deferred, "Should be false");
545 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
546 #endif
547 }
548 }
549
550 void CollectedHeap::accumulate_statistics_all_tlabs() {
551 if (UseTLAB) {
552 assert(SafepointSynchronize::is_at_safepoint() ||
553 !is_init_completed(),
554 "should only accumulate statistics on tlabs at safepoint");
555
556 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
557 }
558 }
559
560 void CollectedHeap::resize_all_tlabs() {
561 if (UseTLAB) {
562 assert(SafepointSynchronize::is_at_safepoint() ||
563 !is_init_completed(),
564 "should only resize tlabs at safepoint");
565
566 ThreadLocalAllocBuffer::resize_all_tlabs();
567 }
568 }
569
570 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
571 if (HeapDumpBeforeFullGC) {
572 GCTraceTime tt("Heap Dump (before full gc): ", PrintGCDetails, false, timer, GCId::create());
573 // We are doing a "major" collection and a heap dump before
574 // major collection has been requested.
575 HeapDumper::dump_heap();
576 }
577 if (PrintClassHistogramBeforeFullGC) {
578 GCTraceTime tt("Class Histogram (before full gc): ", PrintGCDetails, true, timer, GCId::create());
579 VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
580 inspector.doit();
581 }
582 }
583
584 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
585 if (HeapDumpAfterFullGC) {
586 GCTraceTime tt("Heap Dump (after full gc): ", PrintGCDetails, false, timer, GCId::create());
587 HeapDumper::dump_heap();
588 }
589 if (PrintClassHistogramAfterFullGC) {
590 GCTraceTime tt("Class Histogram (after full gc): ", PrintGCDetails, true, timer, GCId::create());
591 VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
592 inspector.doit();
593 }
594 }
595
596 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
597 // It is important to do this in a way such that concurrent readers can't
598 // temporarily think something is in the heap. (Seen this happen in asserts.)
599 _reserved.set_word_size(0);
600 _reserved.set_start(start);
601 _reserved.set_end(end);
602 }
603
604 /////////////// Unit tests ///////////////
605
606 #ifndef PRODUCT
607 void CollectedHeap::test_is_in() {
608 CollectedHeap* heap = Universe::heap();
609
610 uintptr_t epsilon = (uintptr_t) MinObjAlignment;
611 uintptr_t heap_start = (uintptr_t) heap->_reserved.start();
612 uintptr_t heap_end = (uintptr_t) heap->_reserved.end();
613
614 // Test that NULL is not in the heap.
615 assert(!heap->is_in(NULL), "NULL is unexpectedly in the heap");
616
617 // Test that a pointer to before the heap start is reported as outside the heap.
618 assert(heap_start >= ((uintptr_t)NULL + epsilon), "sanity");
619 void* before_heap = (void*)(heap_start - epsilon);
620 assert(!heap->is_in(before_heap),
621 err_msg("before_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(before_heap)));
622
623 // Test that a pointer to after the heap end is reported as outside the heap.
624 assert(heap_end <= ((uintptr_t)-1 - epsilon), "sanity");
625 void* after_heap = (void*)(heap_end + epsilon);
626 assert(!heap->is_in(after_heap),
627 err_msg("after_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(after_heap)));
628 }
629 #endif