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_implementation/shared/gcHeapSummary.hpp"
28 #include "gc_implementation/shared/gcTrace.hpp"
29 #include "gc_implementation/shared/gcTraceTime.hpp"
30 #include "gc_implementation/shared/gcWhen.hpp"
31 #include "gc_implementation/shared/vmGCOperations.hpp"
32 #include "gc_interface/allocTracer.hpp"
33 #include "gc_interface/collectedHeap.hpp"
34 #include "gc_interface/collectedHeap.inline.hpp"
35 #include "memory/barrierSet.inline.hpp"
36 #include "memory/metaspace.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "oops/instanceMirrorKlass.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() : _n_par_threads(0)
164 {
165 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
166 const size_t elements_per_word = HeapWordSize / sizeof(jint);
167 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
168 max_len / elements_per_word);
169
170 _barrier_set = NULL;
171 _is_gc_active = false;
172 _total_collections = _total_full_collections = 0;
173 _gc_cause = _gc_lastcause = GCCause::_no_gc;
174 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
175 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
176
177 if (UsePerfData) {
178 EXCEPTION_MARK;
179
180 // create the gc cause jvmstat counters
181 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
182 80, GCCause::to_string(_gc_cause), CHECK);
183
184 _perf_gc_lastcause =
185 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
186 80, GCCause::to_string(_gc_lastcause), CHECK);
187 }
188 _defer_initial_card_mark = false; // strengthened by subclass in pre_initialize() below.
189 // Create the ring log
190 if (LogEvents) {
191 _gc_heap_log = new GCHeapLog();
192 } else {
193 _gc_heap_log = NULL;
194 }
195 }
196
197 // This interface assumes that it's being called by the
198 // vm thread. It collects the heap assuming that the
199 // heap lock is already held and that we are executing in
200 // the context of the vm thread.
201 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
202 assert(Thread::current()->is_VM_thread(), "Precondition#1");
203 assert(Heap_lock->is_locked(), "Precondition#2");
204 GCCauseSetter gcs(this, cause);
205 switch (cause) {
206 case GCCause::_heap_inspection:
207 case GCCause::_heap_dump:
208 case GCCause::_metadata_GC_threshold : {
209 HandleMark hm;
210 do_full_collection(false); // don't clear all soft refs
211 break;
212 }
213 case GCCause::_last_ditch_collection: {
214 HandleMark hm;
215 do_full_collection(true); // do clear all soft refs
216 break;
217 }
218 default:
219 ShouldNotReachHere(); // Unexpected use of this function
220 }
221 }
222
223 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
224 _barrier_set = barrier_set;
225 oopDesc::set_bs(_barrier_set);
226 }
227
228 void CollectedHeap::pre_initialize() {
229 // Used for ReduceInitialCardMarks (when COMPILER2 is used);
230 // otherwise remains unused.
231 #ifdef COMPILER2
232 _defer_initial_card_mark = ReduceInitialCardMarks && can_elide_tlab_store_barriers()
233 && (DeferInitialCardMark || card_mark_must_follow_store());
234 #else
235 assert(_defer_initial_card_mark == false, "Who would set it?");
236 #endif
237 }
238
239 #ifndef PRODUCT
240 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
241 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
242 for (size_t slot = 0; slot < size; slot += 1) {
243 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
244 "Found badHeapWordValue in post-allocation check");
245 }
246 }
247 }
248
249 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
250 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
251 for (size_t slot = 0; slot < size; slot += 1) {
252 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
253 "Found non badHeapWordValue in pre-allocation check");
254 }
255 }
256 }
257 #endif // PRODUCT
258
259 #ifdef ASSERT
260 void CollectedHeap::check_for_valid_allocation_state() {
261 Thread *thread = Thread::current();
262 // How to choose between a pending exception and a potential
263 // OutOfMemoryError? Don't allow pending exceptions.
264 // This is a VM policy failure, so how do we exhaustively test it?
265 assert(!thread->has_pending_exception(),
266 "shouldn't be allocating with pending exception");
267 if (StrictSafepointChecks) {
268 assert(thread->allow_allocation(),
269 "Allocation done by thread for which allocation is blocked "
270 "by No_Allocation_Verifier!");
271 // Allocation of an oop can always invoke a safepoint,
272 // hence, the true argument
273 thread->check_for_valid_safepoint_state(true);
274 }
275 }
276 #endif
277
278 HeapWord* CollectedHeap::allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size) {
279
280 // Retain tlab and allocate object in shared space if
281 // the amount free in the tlab is too large to discard.
282 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
283 thread->tlab().record_slow_allocation(size);
284 return NULL;
285 }
286
287 // Discard tlab and allocate a new one.
288 // To minimize fragmentation, the last TLAB may be smaller than the rest.
289 size_t new_tlab_size = thread->tlab().compute_size(size);
290
291 thread->tlab().clear_before_allocation();
292
293 if (new_tlab_size == 0) {
294 return NULL;
295 }
296
297 // Allocate a new TLAB...
298 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
299 if (obj == NULL) {
300 return NULL;
301 }
302
303 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
304
305 if (ZeroTLAB) {
306 // ..and clear it.
307 Copy::zero_to_words(obj, new_tlab_size);
308 } else {
309 // ...and zap just allocated object.
310 #ifdef ASSERT
311 // Skip mangling the space corresponding to the object header to
312 // ensure that the returned space is not considered parsable by
313 // any concurrent GC thread.
314 size_t hdr_size = oopDesc::header_size();
315 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
316 #endif // ASSERT
317 }
318 thread->tlab().fill(obj, obj + size, new_tlab_size);
319 return obj;
320 }
321
322 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
323 MemRegion deferred = thread->deferred_card_mark();
324 if (!deferred.is_empty()) {
325 assert(_defer_initial_card_mark, "Otherwise should be empty");
326 {
327 // Verify that the storage points to a parsable object in heap
328 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
329 assert(is_in(old_obj), "Not in allocated heap");
330 assert(!can_elide_initializing_store_barrier(old_obj),
331 "Else should have been filtered in new_store_pre_barrier()");
332 assert(old_obj->is_oop(true), "Not an oop");
333 assert(deferred.word_size() == (size_t)(old_obj->size()),
334 "Mismatch: multiple objects?");
335 }
336 BarrierSet* bs = barrier_set();
337 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
338 bs->write_region(deferred);
339 // "Clear" the deferred_card_mark field
340 thread->set_deferred_card_mark(MemRegion());
341 }
342 assert(thread->deferred_card_mark().is_empty(), "invariant");
343 }
344
345 size_t CollectedHeap::max_tlab_size() const {
346 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
347 // This restriction could be removed by enabling filling with multiple arrays.
348 // If we compute that the reasonable way as
349 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
350 // we'll overflow on the multiply, so we do the divide first.
351 // We actually lose a little by dividing first,
352 // but that just makes the TLAB somewhat smaller than the biggest array,
353 // which is fine, since we'll be able to fill that.
354 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
355 sizeof(jint) *
356 ((juint) max_jint / (size_t) HeapWordSize);
357 return align_size_down(max_int_size, MinObjAlignment);
358 }
359
360 // Helper for ReduceInitialCardMarks. For performance,
361 // compiled code may elide card-marks for initializing stores
362 // to a newly allocated object along the fast-path. We
363 // compensate for such elided card-marks as follows:
364 // (a) Generational, non-concurrent collectors, such as
365 // GenCollectedHeap(ParNew,DefNew,Tenured) and
366 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
367 // need the card-mark if and only if the region is
368 // in the old gen, and do not care if the card-mark
369 // succeeds or precedes the initializing stores themselves,
370 // so long as the card-mark is completed before the next
371 // scavenge. For all these cases, we can do a card mark
372 // at the point at which we do a slow path allocation
373 // in the old gen, i.e. in this call.
374 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
375 // in addition that the card-mark for an old gen allocated
376 // object strictly follow any associated initializing stores.
377 // In these cases, the memRegion remembered below is
378 // used to card-mark the entire region either just before the next
379 // slow-path allocation by this thread or just before the next scavenge or
380 // CMS-associated safepoint, whichever of these events happens first.
381 // (The implicit assumption is that the object has been fully
382 // initialized by this point, a fact that we assert when doing the
383 // card-mark.)
384 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
385 // G1 concurrent marking is in progress an SATB (pre-write-)barrier is
386 // is used to remember the pre-value of any store. Initializing
387 // stores will not need this barrier, so we need not worry about
388 // compensating for the missing pre-barrier here. Turning now
389 // to the post-barrier, we note that G1 needs a RS update barrier
390 // which simply enqueues a (sequence of) dirty cards which may
391 // optionally be refined by the concurrent update threads. Note
392 // that this barrier need only be applied to a non-young write,
393 // but, like in CMS, because of the presence of concurrent refinement
394 // (much like CMS' precleaning), must strictly follow the oop-store.
395 // Thus, using the same protocol for maintaining the intended
396 // invariants turns out, serendepitously, to be the same for both
397 // G1 and CMS.
398 //
399 // For any future collector, this code should be reexamined with
400 // that specific collector in mind, and the documentation above suitably
401 // extended and updated.
402 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
403 // If a previous card-mark was deferred, flush it now.
404 flush_deferred_store_barrier(thread);
405 if (can_elide_initializing_store_barrier(new_obj)) {
406 // The deferred_card_mark region should be empty
407 // following the flush above.
408 assert(thread->deferred_card_mark().is_empty(), "Error");
409 } else {
410 MemRegion mr((HeapWord*)new_obj, new_obj->size());
411 assert(!mr.is_empty(), "Error");
412 if (_defer_initial_card_mark) {
413 // Defer the card mark
414 thread->set_deferred_card_mark(mr);
415 } else {
416 // Do the card mark
417 BarrierSet* bs = barrier_set();
418 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
419 bs->write_region(mr);
420 }
421 }
422 return new_obj;
423 }
424
425 size_t CollectedHeap::filler_array_hdr_size() {
426 return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
427 }
428
429 size_t CollectedHeap::filler_array_min_size() {
430 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
431 }
432
433 #ifdef ASSERT
434 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
435 {
436 assert(words >= min_fill_size(), "too small to fill");
437 assert(words % MinObjAlignment == 0, "unaligned size");
438 assert(Universe::heap()->is_in_reserved(start), "not in heap");
439 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
440 }
441
442 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
443 {
444 if (ZapFillerObjects && zap) {
445 Copy::fill_to_words(start + filler_array_hdr_size(),
446 words - filler_array_hdr_size(), 0XDEAFBABE);
447 }
448 }
449 #endif // ASSERT
450
451 void
452 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
453 {
454 assert(words >= filler_array_min_size(), "too small for an array");
455 assert(words <= filler_array_max_size(), "too big for a single object");
456
457 const size_t payload_size = words - filler_array_hdr_size();
458 const size_t len = payload_size * HeapWordSize / sizeof(jint);
459 assert((int)len >= 0, err_msg("size too large " SIZE_FORMAT " becomes %d", words, (int)len));
460
461 // Set the length first for concurrent GC.
462 ((arrayOop)start)->set_length((int)len);
463 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
464 DEBUG_ONLY(zap_filler_array(start, words, zap);)
465 }
466
467 void
468 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
469 {
470 assert(words <= filler_array_max_size(), "too big for a single object");
471
472 if (words >= filler_array_min_size()) {
473 fill_with_array(start, words, zap);
474 } else if (words > 0) {
475 assert(words == min_fill_size(), "unaligned size");
476 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
477 }
478 }
479
480 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
481 {
482 DEBUG_ONLY(fill_args_check(start, words);)
483 HandleMark hm; // Free handles before leaving.
484 fill_with_object_impl(start, words, zap);
485 }
486
487 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
488 {
489 DEBUG_ONLY(fill_args_check(start, words);)
490 HandleMark hm; // Free handles before leaving.
491
492 #ifdef _LP64
493 // A single array can fill ~8G, so multiple objects are needed only in 64-bit.
494 // First fill with arrays, ensuring that any remaining space is big enough to
495 // fill. The remainder is filled with a single object.
496 const size_t min = min_fill_size();
497 const size_t max = filler_array_max_size();
498 while (words > max) {
499 const size_t cur = words - max >= min ? max : max - min;
500 fill_with_array(start, cur, zap);
501 start += cur;
502 words -= cur;
503 }
504 #endif
505
506 fill_with_object_impl(start, words, zap);
507 }
508
509 void CollectedHeap::post_initialize() {
510 collector_policy()->post_heap_initialize();
511 }
512
513 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
514 guarantee(false, "thread-local allocation buffers not supported");
515 return NULL;
516 }
517
518 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
519 // The second disjunct in the assertion below makes a concession
520 // for the start-up verification done while the VM is being
521 // created. Callers be careful that you know that mutators
522 // aren't going to interfere -- for instance, this is permissible
523 // if we are still single-threaded and have either not yet
524 // started allocating (nothing much to verify) or we have
525 // started allocating but are now a full-fledged JavaThread
526 // (and have thus made our TLAB's) available for filling.
527 assert(SafepointSynchronize::is_at_safepoint() ||
528 !is_init_completed(),
529 "Should only be called at a safepoint or at start-up"
530 " otherwise concurrent mutator activity may make heap "
531 " unparsable again");
532 const bool use_tlab = UseTLAB;
533 const bool deferred = _defer_initial_card_mark;
534 // The main thread starts allocating via a TLAB even before it
535 // has added itself to the threads list at vm boot-up.
536 assert(!use_tlab || Threads::first() != NULL,
537 "Attempt to fill tlabs before main thread has been added"
538 " to threads list is doomed to failure!");
539 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
540 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
541 #ifdef COMPILER2
542 // The deferred store barriers must all have been flushed to the
543 // card-table (or other remembered set structure) before GC starts
544 // processing the card-table (or other remembered set).
545 if (deferred) flush_deferred_store_barrier(thread);
546 #else
547 assert(!deferred, "Should be false");
548 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
549 #endif
550 }
551 }
552
553 void CollectedHeap::accumulate_statistics_all_tlabs() {
554 if (UseTLAB) {
555 assert(SafepointSynchronize::is_at_safepoint() ||
556 !is_init_completed(),
557 "should only accumulate statistics on tlabs at safepoint");
558
559 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
560 }
561 }
562
563 void CollectedHeap::resize_all_tlabs() {
564 if (UseTLAB) {
565 assert(SafepointSynchronize::is_at_safepoint() ||
566 !is_init_completed(),
567 "should only resize tlabs at safepoint");
568
569 ThreadLocalAllocBuffer::resize_all_tlabs();
570 }
571 }
572
573 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
574 if (HeapDumpBeforeFullGC) {
575 GCTraceTime tt("Heap Dump (before full gc): ", PrintGCDetails, false, timer, GCId::create());
576 // We are doing a "major" collection and a heap dump before
577 // major collection has been requested.
578 HeapDumper::dump_heap();
579 }
580 if (PrintClassHistogramBeforeFullGC) {
581 GCTraceTime tt("Class Histogram (before full gc): ", PrintGCDetails, true, timer, GCId::create());
582 VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
583 inspector.doit();
584 }
585 }
586
587 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
588 if (HeapDumpAfterFullGC) {
589 GCTraceTime tt("Heap Dump (after full gc): ", PrintGCDetails, false, timer, GCId::create());
590 HeapDumper::dump_heap();
591 }
592 if (PrintClassHistogramAfterFullGC) {
593 GCTraceTime tt("Class Histogram (after full gc): ", PrintGCDetails, true, timer, GCId::create());
594 VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
595 inspector.doit();
596 }
597 }
598
599 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
600 // It is important to do this in a way such that concurrent readers can't
601 // temporarily think something is in the heap. (Seen this happen in asserts.)
602 _reserved.set_word_size(0);
603 _reserved.set_start(start);
604 _reserved.set_end(end);
605 }
606
607 /////////////// Unit tests ///////////////
608
609 #ifndef PRODUCT
610 void CollectedHeap::test_is_in() {
611 CollectedHeap* heap = Universe::heap();
612
613 uintptr_t epsilon = (uintptr_t) MinObjAlignment;
614 uintptr_t heap_start = (uintptr_t) heap->_reserved.start();
615 uintptr_t heap_end = (uintptr_t) heap->_reserved.end();
616
617 // Test that NULL is not in the heap.
618 assert(!heap->is_in(NULL), "NULL is unexpectedly in the heap");
619
620 // Test that a pointer to before the heap start is reported as outside the heap.
621 assert(heap_start >= ((uintptr_t)NULL + epsilon), "sanity");
622 void* before_heap = (void*)(heap_start - epsilon);
623 assert(!heap->is_in(before_heap),
624 err_msg("before_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(before_heap)));
625
626 // Test that a pointer to after the heap end is reported as outside the heap.
627 assert(heap_end <= ((uintptr_t)-1 - epsilon), "sanity");
628 void* after_heap = (void*)(heap_end + epsilon);
629 assert(!heap->is_in(after_heap),
630 err_msg("after_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(after_heap)));
631 }
632 #endif