1 /*
2 * Copyright (c) 2001, 2020, 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/metaspace.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "oops/instanceMirrorKlass.hpp"
38 #include "runtime/init.hpp"
39 #include "runtime/thread.inline.hpp"
40 #include "services/heapDumper.hpp"
41
42
43 #ifdef ASSERT
44 int CollectedHeap::_fire_out_of_memory_count = 0;
45 #endif
46
47 size_t CollectedHeap::_filler_array_max_size = 0;
48
49 template <>
50 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
51 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
52 st->print_raw(m);
53 }
54
55 void GCHeapLog::log_heap(bool before) {
56 if (!should_log()) {
57 return;
58 }
59
60 double timestamp = fetch_timestamp();
61 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
62 int index = compute_log_index();
63 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
64 _records[index].timestamp = timestamp;
65 _records[index].data.is_before = before;
66 stringStream st(_records[index].data.buffer(), _records[index].data.size());
67 if (before) {
68 Universe::print_heap_before_gc(&st, true);
69 } else {
70 Universe::print_heap_after_gc(&st, true);
71 }
72 }
73
74 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
75 size_t capacity_in_words = capacity() / HeapWordSize;
76
77 return VirtualSpaceSummary(
78 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
79 }
80
81 GCHeapSummary CollectedHeap::create_heap_summary() {
82 VirtualSpaceSummary heap_space = create_heap_space_summary();
83 return GCHeapSummary(heap_space, used());
84 }
85
86 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
87 const MetaspaceSizes meta_space(
88 MetaspaceAux::committed_bytes(),
89 MetaspaceAux::used_bytes(),
90 MetaspaceAux::reserved_bytes());
91 const MetaspaceSizes data_space(
92 MetaspaceAux::committed_bytes(Metaspace::NonClassType),
93 MetaspaceAux::used_bytes(Metaspace::NonClassType),
94 MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
95 const MetaspaceSizes class_space(
96 MetaspaceAux::committed_bytes(Metaspace::ClassType),
97 MetaspaceAux::used_bytes(Metaspace::ClassType),
98 MetaspaceAux::reserved_bytes(Metaspace::ClassType));
99
100 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
101 MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
102 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
103 MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
104
105 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
106 ms_chunk_free_list_summary, class_chunk_free_list_summary);
107 }
108
109 void CollectedHeap::print_heap_before_gc() {
110 if (PrintHeapAtGC) {
111 Universe::print_heap_before_gc();
112 }
113 if (_gc_heap_log != NULL) {
114 _gc_heap_log->log_heap_before();
115 }
116 }
117
118 void CollectedHeap::print_heap_after_gc() {
119 if (PrintHeapAtGC) {
120 Universe::print_heap_after_gc();
121 }
122 if (_gc_heap_log != NULL) {
123 _gc_heap_log->log_heap_after();
124 }
125 }
126
127 void CollectedHeap::register_nmethod(nmethod* nm) {
128 assert_locked_or_safepoint(CodeCache_lock);
129 }
130
131 void CollectedHeap::unregister_nmethod(nmethod* nm) {
132 assert_locked_or_safepoint(CodeCache_lock);
133 }
134
135 void CollectedHeap::trace_heap(GCWhen::Type when, GCTracer* gc_tracer) {
136 const GCHeapSummary& heap_summary = create_heap_summary();
137 gc_tracer->report_gc_heap_summary(when, heap_summary);
138
139 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
140 gc_tracer->report_metaspace_summary(when, metaspace_summary);
141 }
142
143 void CollectedHeap::trace_heap_before_gc(GCTracer* gc_tracer) {
144 trace_heap(GCWhen::BeforeGC, gc_tracer);
145 }
146
147 void CollectedHeap::trace_heap_after_gc(GCTracer* gc_tracer) {
148 trace_heap(GCWhen::AfterGC, gc_tracer);
149 }
150
151 // Memory state functions.
152
153
154 CollectedHeap::CollectedHeap() : _n_par_threads(0)
155 {
156 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
157 const size_t elements_per_word = HeapWordSize / sizeof(jint);
158 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
159 max_len / elements_per_word);
160
161 _barrier_set = NULL;
162 _is_gc_active = false;
163 _total_collections = _total_full_collections = 0;
164 _gc_cause = _gc_lastcause = GCCause::_no_gc;
165 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
166 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
167
168 if (UsePerfData) {
169 EXCEPTION_MARK;
170
171 // create the gc cause jvmstat counters
172 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
173 80, GCCause::to_string(_gc_cause), CHECK);
174
175 _perf_gc_lastcause =
176 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
177 80, GCCause::to_string(_gc_lastcause), CHECK);
178 }
179 _defer_initial_card_mark = false; // strengthened by subclass in pre_initialize() below.
180 // Create the ring log
181 if (LogEvents) {
182 _gc_heap_log = new GCHeapLog();
183 } else {
184 _gc_heap_log = NULL;
185 }
186 }
187
188 // This interface assumes that it's being called by the
189 // vm thread. It collects the heap assuming that the
190 // heap lock is already held and that we are executing in
191 // the context of the vm thread.
192 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
193 assert(Thread::current()->is_VM_thread(), "Precondition#1");
194 assert(Heap_lock->is_locked(), "Precondition#2");
195 GCCauseSetter gcs(this, cause);
196 switch (cause) {
197 case GCCause::_heap_inspection:
198 case GCCause::_heap_dump:
199 case GCCause::_metadata_GC_threshold : {
200 HandleMark hm;
201 do_full_collection(false); // don't clear all soft refs
202 break;
203 }
204 case GCCause::_last_ditch_collection: {
205 HandleMark hm;
206 do_full_collection(true); // do clear all soft refs
207 break;
208 }
209 default:
210 ShouldNotReachHere(); // Unexpected use of this function
211 }
212 }
213
214 void CollectedHeap::pre_initialize() {
215 // Used for ReduceInitialCardMarks (when COMPILER2 is used);
216 // otherwise remains unused.
217 #ifdef COMPILER2
218 _defer_initial_card_mark = ReduceInitialCardMarks && can_elide_tlab_store_barriers()
219 && (DeferInitialCardMark || card_mark_must_follow_store());
220 #else
221 assert(_defer_initial_card_mark == false, "Who would set it?");
222 #endif
223 }
224
225 #ifndef PRODUCT
226 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
227 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
228 for (size_t slot = 0; slot < size; slot += 1) {
229 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
230 "Found badHeapWordValue in post-allocation check");
231 }
232 }
233 }
234
235 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
236 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
237 for (size_t slot = 0; slot < size; slot += 1) {
238 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
239 "Found non badHeapWordValue in pre-allocation check");
240 }
241 }
242 }
243 #endif // PRODUCT
244
245 #ifdef ASSERT
246 void CollectedHeap::check_for_valid_allocation_state() {
247 Thread *thread = Thread::current();
248 // How to choose between a pending exception and a potential
249 // OutOfMemoryError? Don't allow pending exceptions.
250 // This is a VM policy failure, so how do we exhaustively test it?
251 assert(!thread->has_pending_exception(),
252 "shouldn't be allocating with pending exception");
253 if (StrictSafepointChecks) {
254 assert(thread->allow_allocation(),
255 "Allocation done by thread for which allocation is blocked "
256 "by No_Allocation_Verifier!");
257 // Allocation of an oop can always invoke a safepoint,
258 // hence, the true argument
259 thread->check_for_valid_safepoint_state(true);
260 }
261 }
262 #endif
263
264 HeapWord* CollectedHeap::allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size) {
265
266 // Retain tlab and allocate object in shared space if
267 // the amount free in the tlab is too large to discard.
268 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
269 thread->tlab().record_slow_allocation(size);
270 return NULL;
271 }
272
273 // Discard tlab and allocate a new one.
274 // To minimize fragmentation, the last TLAB may be smaller than the rest.
275 size_t new_tlab_size = thread->tlab().compute_size(size);
276
277 thread->tlab().clear_before_allocation();
278
279 if (new_tlab_size == 0) {
280 return NULL;
281 }
282
283 // Allocate a new TLAB...
284 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
285 if (obj == NULL) {
286 return NULL;
287 }
288
289 if (ZeroTLAB) {
290 // ..and clear it.
291 Copy::zero_to_words(obj, new_tlab_size);
292 } else {
293 // ...and zap just allocated object.
294 #ifdef ASSERT
295 // Skip mangling the space corresponding to the object header to
296 // ensure that the returned space is not considered parsable by
297 // any concurrent GC thread.
298 size_t hdr_size = oopDesc::header_size();
299 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
300 #endif // ASSERT
301 }
302 thread->tlab().fill(obj, obj + size, new_tlab_size);
303 return obj;
304 }
305
306 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
307 MemRegion deferred = thread->deferred_card_mark();
308 if (!deferred.is_empty()) {
309 assert(_defer_initial_card_mark, "Otherwise should be empty");
310 {
311 // Verify that the storage points to a parsable object in heap
312 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
313 assert(is_in(old_obj), "Not in allocated heap");
314 assert(!can_elide_initializing_store_barrier(old_obj),
315 "Else should have been filtered in new_store_pre_barrier()");
316 assert(old_obj->is_oop(true), "Not an oop");
317 assert(deferred.word_size() == (size_t)(old_obj->size()),
318 "Mismatch: multiple objects?");
319 }
320 BarrierSet* bs = barrier_set();
321 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
322 bs->write_region(deferred);
323 // "Clear" the deferred_card_mark field
324 thread->set_deferred_card_mark(MemRegion());
325 }
326 assert(thread->deferred_card_mark().is_empty(), "invariant");
327 }
328
329 size_t CollectedHeap::max_tlab_size() const {
330 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
331 // This restriction could be removed by enabling filling with multiple arrays.
332 // If we compute that the reasonable way as
333 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
334 // we'll overflow on the multiply, so we do the divide first.
335 // We actually lose a little by dividing first,
336 // but that just makes the TLAB somewhat smaller than the biggest array,
337 // which is fine, since we'll be able to fill that.
338 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
339 sizeof(jint) *
340 ((juint) max_jint / (size_t) HeapWordSize);
341 return align_size_down(max_int_size, MinObjAlignment);
342 }
343
344 // Helper for ReduceInitialCardMarks. For performance,
345 // compiled code may elide card-marks for initializing stores
346 // to a newly allocated object along the fast-path. We
347 // compensate for such elided card-marks as follows:
348 // (a) Generational, non-concurrent collectors, such as
349 // GenCollectedHeap(ParNew,DefNew,Tenured) and
350 // ParallelScavengeHeap(ParallelGC, ParallelOldGC)
351 // need the card-mark if and only if the region is
352 // in the old gen, and do not care if the card-mark
353 // succeeds or precedes the initializing stores themselves,
354 // so long as the card-mark is completed before the next
355 // scavenge. For all these cases, we can do a card mark
356 // at the point at which we do a slow path allocation
357 // in the old gen, i.e. in this call.
358 // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
359 // in addition that the card-mark for an old gen allocated
360 // object strictly follow any associated initializing stores.
361 // In these cases, the memRegion remembered below is
362 // used to card-mark the entire region either just before the next
363 // slow-path allocation by this thread or just before the next scavenge or
364 // CMS-associated safepoint, whichever of these events happens first.
365 // (The implicit assumption is that the object has been fully
366 // initialized by this point, a fact that we assert when doing the
367 // card-mark.)
368 // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
369 // G1 concurrent marking is in progress an SATB (pre-write-)barrier is
370 // is used to remember the pre-value of any store. Initializing
371 // stores will not need this barrier, so we need not worry about
372 // compensating for the missing pre-barrier here. Turning now
373 // to the post-barrier, we note that G1 needs a RS update barrier
374 // which simply enqueues a (sequence of) dirty cards which may
375 // optionally be refined by the concurrent update threads. Note
376 // that this barrier need only be applied to a non-young write,
377 // but, like in CMS, because of the presence of concurrent refinement
378 // (much like CMS' precleaning), must strictly follow the oop-store.
379 // Thus, using the same protocol for maintaining the intended
380 // invariants turns out, serendepitously, to be the same for both
381 // G1 and CMS.
382 //
383 // For any future collector, this code should be reexamined with
384 // that specific collector in mind, and the documentation above suitably
385 // extended and updated.
386 oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
387 // If a previous card-mark was deferred, flush it now.
388 flush_deferred_store_barrier(thread);
389 if (can_elide_initializing_store_barrier(new_obj)) {
390 // The deferred_card_mark region should be empty
391 // following the flush above.
392 assert(thread->deferred_card_mark().is_empty(), "Error");
393 } else {
394 MemRegion mr((HeapWord*)new_obj, new_obj->size());
395 assert(!mr.is_empty(), "Error");
396 if (_defer_initial_card_mark) {
397 // Defer the card mark
398 thread->set_deferred_card_mark(mr);
399 } else {
400 // Do the card mark
401 BarrierSet* bs = barrier_set();
402 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
403 bs->write_region(mr);
404 }
405 }
406 return new_obj;
407 }
408
409 size_t CollectedHeap::filler_array_hdr_size() {
410 return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
411 }
412
413 size_t CollectedHeap::filler_array_min_size() {
414 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
415 }
416
417 #ifdef ASSERT
418 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
419 {
420 assert(words >= min_fill_size(), "too small to fill");
421 assert(words % MinObjAlignment == 0, "unaligned size");
422 assert(Universe::heap()->is_in_reserved(start), "not in heap");
423 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
424 }
425
426 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
427 {
428 if (ZapFillerObjects && zap) {
429 Copy::fill_to_words(start + filler_array_hdr_size(),
430 words - filler_array_hdr_size(), 0XDEAFBABE);
431 }
432 }
433 #endif // ASSERT
434
435 void
436 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
437 {
438 assert(words >= filler_array_min_size(), "too small for an array");
439 assert(words <= filler_array_max_size(), "too big for a single object");
440
441 const size_t payload_size = words - filler_array_hdr_size();
442 const size_t len = payload_size * HeapWordSize / sizeof(jint);
443 assert((int)len >= 0, err_msg("size too large " SIZE_FORMAT " becomes %d", words, (int)len));
444
445 // Set the length first for concurrent GC.
446 ((arrayOop)start)->set_length((int)len);
447 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
448 DEBUG_ONLY(zap_filler_array(start, words, zap);)
449 }
450
451 void
452 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
453 {
454 assert(words <= filler_array_max_size(), "too big for a single object");
455
456 if (words >= filler_array_min_size()) {
457 fill_with_array(start, words, zap);
458 } else if (words > 0) {
459 assert(words == min_fill_size(), "unaligned size");
460 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
461 }
462 }
463
464 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
465 {
466 DEBUG_ONLY(fill_args_check(start, words);)
467 HandleMark hm; // Free handles before leaving.
468 fill_with_object_impl(start, words, zap);
469 }
470
471 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
472 {
473 DEBUG_ONLY(fill_args_check(start, words);)
474 HandleMark hm; // Free handles before leaving.
475
476 #ifdef _LP64
477 // A single array can fill ~8G, so multiple objects are needed only in 64-bit.
478 // First fill with arrays, ensuring that any remaining space is big enough to
479 // fill. The remainder is filled with a single object.
480 const size_t min = min_fill_size();
481 const size_t max = filler_array_max_size();
482 while (words > max) {
483 const size_t cur = words - max >= min ? max : max - min;
484 fill_with_array(start, cur, zap);
485 start += cur;
486 words -= cur;
487 }
488 #endif
489
490 fill_with_object_impl(start, words, zap);
491 }
492
493 void CollectedHeap::post_initialize() {
494 collector_policy()->post_heap_initialize();
495 }
496
497 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
498 guarantee(false, "thread-local allocation buffers not supported");
499 return NULL;
500 }
501
502 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
503 // The second disjunct in the assertion below makes a concession
504 // for the start-up verification done while the VM is being
505 // created. Callers be careful that you know that mutators
506 // aren't going to interfere -- for instance, this is permissible
507 // if we are still single-threaded and have either not yet
508 // started allocating (nothing much to verify) or we have
509 // started allocating but are now a full-fledged JavaThread
510 // (and have thus made our TLAB's) available for filling.
511 assert(SafepointSynchronize::is_at_safepoint() ||
512 !is_init_completed(),
513 "Should only be called at a safepoint or at start-up"
514 " otherwise concurrent mutator activity may make heap "
515 " unparsable again");
516 const bool use_tlab = UseTLAB;
517 const bool deferred = _defer_initial_card_mark;
518 // The main thread starts allocating via a TLAB even before it
519 // has added itself to the threads list at vm boot-up.
520 assert(!use_tlab || Threads::first() != NULL,
521 "Attempt to fill tlabs before main thread has been added"
522 " to threads list is doomed to failure!");
523 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
524 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
525 #ifdef COMPILER2
526 // The deferred store barriers must all have been flushed to the
527 // card-table (or other remembered set structure) before GC starts
528 // processing the card-table (or other remembered set).
529 if (deferred) flush_deferred_store_barrier(thread);
530 #else
531 assert(!deferred, "Should be false");
532 assert(thread->deferred_card_mark().is_empty(), "Should be empty");
533 #endif
534 }
535 }
536
537 void CollectedHeap::accumulate_statistics_all_tlabs() {
538 if (UseTLAB) {
539 assert(SafepointSynchronize::is_at_safepoint() ||
540 !is_init_completed(),
541 "should only accumulate statistics on tlabs at safepoint");
542
543 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
544 }
545 }
546
547 void CollectedHeap::resize_all_tlabs() {
548 if (UseTLAB) {
549 assert(SafepointSynchronize::is_at_safepoint() ||
550 !is_init_completed(),
551 "should only resize tlabs at safepoint");
552
553 ThreadLocalAllocBuffer::resize_all_tlabs();
554 }
555 }
556
557 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
558 if (HeapDumpBeforeFullGC) {
559 GCTraceTime tt("Heap Dump (before full gc): ", PrintGCDetails, false, timer, GCId::create());
560 // We are doing a "major" collection and a heap dump before
561 // major collection has been requested.
562 HeapDumper::dump_heap();
563 }
564 if (PrintClassHistogramBeforeFullGC) {
565 GCTraceTime tt("Class Histogram (before full gc): ", PrintGCDetails, true, timer, GCId::create());
566 VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
567 inspector.doit();
568 }
569 }
570
571 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
572 if (HeapDumpAfterFullGC) {
573 GCTraceTime tt("Heap Dump (after full gc): ", PrintGCDetails, false, timer, GCId::create());
574 HeapDumper::dump_heap();
575 }
576 if (PrintClassHistogramAfterFullGC) {
577 GCTraceTime tt("Class Histogram (after full gc): ", PrintGCDetails, true, timer, GCId::create());
578 VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */);
579 inspector.doit();
580 }
581 }
582
583 /////////////// Unit tests ///////////////
584
585 #ifndef PRODUCT
586 void CollectedHeap::test_is_in() {
587 CollectedHeap* heap = Universe::heap();
588
589 uintptr_t epsilon = (uintptr_t) MinObjAlignment;
590 uintptr_t heap_start = (uintptr_t) heap->_reserved.start();
591 uintptr_t heap_end = (uintptr_t) heap->_reserved.end();
592
593 // Test that NULL is not in the heap.
594 assert(!heap->is_in(NULL), "NULL is unexpectedly in the heap");
595
596 // Test that a pointer to before the heap start is reported as outside the heap.
597 assert(heap_start >= ((uintptr_t)NULL + epsilon), "sanity");
598 void* before_heap = (void*)(heap_start - epsilon);
599 assert(!heap->is_in(before_heap),
600 err_msg("before_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(before_heap)));
601
602 // Test that a pointer to after the heap end is reported as outside the heap.
603 assert(heap_end <= ((uintptr_t)-1 - epsilon), "sanity");
604 void* after_heap = (void*)(heap_end + epsilon);
605 assert(!heap->is_in(after_heap),
606 err_msg("after_heap: " PTR_FORMAT " is unexpectedly in the heap", p2i(after_heap)));
607 }
608 #endif
609
610 void CollectedHeap::shutdown() {
611 // Default implementation does nothing.
612 }
613
614 void CollectedHeap::accumulate_statistics_all_gclabs() {
615 // Default implementation does nothing.
616 }
617
618 bool CollectedHeap::supports_object_pinning() const {
619 return false;
620 }
621
622 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
623 ShouldNotReachHere();
624 return NULL;
625 }
626
627 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
628 ShouldNotReachHere();
629 }