1 /*
2 * Copyright (c) 2001, 2016, 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 "gc/parallel/adjoiningGenerations.hpp"
27 #include "gc/parallel/adjoiningVirtualSpaces.hpp"
28 #include "gc/parallel/cardTableExtension.hpp"
29 #include "gc/parallel/gcTaskManager.hpp"
30 #include "gc/parallel/generationSizer.hpp"
31 #include "gc/parallel/objectStartArray.inline.hpp"
32 #include "gc/parallel/parallelScavengeHeap.inline.hpp"
33 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
34 #include "gc/parallel/psMarkSweep.hpp"
35 #include "gc/parallel/psParallelCompact.inline.hpp"
36 #include "gc/parallel/psPromotionManager.hpp"
37 #include "gc/parallel/psScavenge.hpp"
38 #include "gc/parallel/vmPSOperations.hpp"
39 #include "gc/shared/gcHeapSummary.hpp"
40 #include "gc/shared/gcLocker.inline.hpp"
41 #include "gc/shared/gcWhen.hpp"
42 #include "logging/log.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "runtime/handles.inline.hpp"
45 #include "runtime/java.hpp"
46 #include "runtime/vmThread.hpp"
47 #include "services/memTracker.hpp"
48 #include "utilities/vmError.hpp"
49
50 PSYoungGen* ParallelScavengeHeap::_young_gen = NULL;
51 PSOldGen* ParallelScavengeHeap::_old_gen = NULL;
52 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
53 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
54 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
55
56 jint ParallelScavengeHeap::initialize() {
57 CollectedHeap::pre_initialize();
58
59 const size_t heap_size = _collector_policy->max_heap_byte_size();
60
61 ReservedSpace heap_rs = Universe::reserve_heap(heap_size, _collector_policy->heap_alignment());
62
63 os::trace_page_sizes("Heap",
64 _collector_policy->min_heap_byte_size(),
65 heap_size,
66 generation_alignment(),
67 heap_rs.base(),
68 heap_rs.size());
69
70 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
71
72 CardTableExtension* const barrier_set = new CardTableExtension(reserved_region());
73 barrier_set->initialize();
74 set_barrier_set(barrier_set);
75
76 // Make up the generations
77 // Calculate the maximum size that a generation can grow. This
78 // includes growth into the other generation. Note that the
79 // parameter _max_gen_size is kept as the maximum
80 // size of the generation as the boundaries currently stand.
81 // _max_gen_size is still used as that value.
82 double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
83 double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
84
85 _gens = new AdjoiningGenerations(heap_rs, _collector_policy, generation_alignment());
86
87 _old_gen = _gens->old_gen();
88 _young_gen = _gens->young_gen();
89
90 const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
91 const size_t old_capacity = _old_gen->capacity_in_bytes();
92 const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
93 _size_policy =
94 new PSAdaptiveSizePolicy(eden_capacity,
95 initial_promo_size,
96 young_gen()->to_space()->capacity_in_bytes(),
97 _collector_policy->gen_alignment(),
98 max_gc_pause_sec,
99 max_gc_minor_pause_sec,
100 GCTimeRatio
101 );
102
103 assert(!UseAdaptiveGCBoundary ||
104 (old_gen()->virtual_space()->high_boundary() ==
105 young_gen()->virtual_space()->low_boundary()),
106 "Boundaries must meet");
107 // initialize the policy counters - 2 collectors, 3 generations
108 _gc_policy_counters =
109 new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
110
111 // Set up the GCTaskManager
112 _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
113
114 if (UseParallelOldGC && !PSParallelCompact::initialize()) {
115 return JNI_ENOMEM;
116 }
117
118 return JNI_OK;
119 }
120
121 void ParallelScavengeHeap::post_initialize() {
122 // Need to init the tenuring threshold
123 PSScavenge::initialize();
124 if (UseParallelOldGC) {
125 PSParallelCompact::post_initialize();
126 } else {
127 PSMarkSweep::initialize();
128 }
129 PSPromotionManager::initialize();
130 }
131
132 void ParallelScavengeHeap::update_counters() {
133 young_gen()->update_counters();
134 old_gen()->update_counters();
135 MetaspaceCounters::update_performance_counters();
136 CompressedClassSpaceCounters::update_performance_counters();
137 }
138
139 size_t ParallelScavengeHeap::capacity() const {
140 size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
141 return value;
142 }
143
144 size_t ParallelScavengeHeap::used() const {
145 size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
146 return value;
147 }
148
149 bool ParallelScavengeHeap::is_maximal_no_gc() const {
150 return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
151 }
152
153
154 size_t ParallelScavengeHeap::max_capacity() const {
155 size_t estimated = reserved_region().byte_size();
156 if (UseAdaptiveSizePolicy) {
157 estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
158 } else {
159 estimated -= young_gen()->to_space()->capacity_in_bytes();
160 }
161 return MAX2(estimated, capacity());
162 }
163
164 bool ParallelScavengeHeap::is_in(const void* p) const {
165 return young_gen()->is_in(p) || old_gen()->is_in(p);
166 }
167
168 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
169 return young_gen()->is_in_reserved(p) || old_gen()->is_in_reserved(p);
170 }
171
172 bool ParallelScavengeHeap::is_scavengable(const void* addr) {
173 return is_in_young((oop)addr);
174 }
175
176 // There are two levels of allocation policy here.
177 //
178 // When an allocation request fails, the requesting thread must invoke a VM
179 // operation, transfer control to the VM thread, and await the results of a
180 // garbage collection. That is quite expensive, and we should avoid doing it
181 // multiple times if possible.
182 //
183 // To accomplish this, we have a basic allocation policy, and also a
184 // failed allocation policy.
185 //
186 // The basic allocation policy controls how you allocate memory without
187 // attempting garbage collection. It is okay to grab locks and
188 // expand the heap, if that can be done without coming to a safepoint.
189 // It is likely that the basic allocation policy will not be very
190 // aggressive.
191 //
192 // The failed allocation policy is invoked from the VM thread after
193 // the basic allocation policy is unable to satisfy a mem_allocate
194 // request. This policy needs to cover the entire range of collection,
195 // heap expansion, and out-of-memory conditions. It should make every
196 // attempt to allocate the requested memory.
197
198 // Basic allocation policy. Should never be called at a safepoint, or
199 // from the VM thread.
200 //
201 // This method must handle cases where many mem_allocate requests fail
202 // simultaneously. When that happens, only one VM operation will succeed,
203 // and the rest will not be executed. For that reason, this method loops
204 // during failed allocation attempts. If the java heap becomes exhausted,
205 // we rely on the size_policy object to force a bail out.
206 HeapWord* ParallelScavengeHeap::mem_allocate(
207 size_t size,
208 bool* gc_overhead_limit_was_exceeded) {
209 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
210 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
211 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
212
213 // In general gc_overhead_limit_was_exceeded should be false so
214 // set it so here and reset it to true only if the gc time
215 // limit is being exceeded as checked below.
216 *gc_overhead_limit_was_exceeded = false;
217
218 HeapWord* result = young_gen()->allocate(size);
219
220 uint loop_count = 0;
221 uint gc_count = 0;
222 uint gclocker_stalled_count = 0;
223
224 while (result == NULL) {
225 // We don't want to have multiple collections for a single filled generation.
226 // To prevent this, each thread tracks the total_collections() value, and if
227 // the count has changed, does not do a new collection.
228 //
229 // The collection count must be read only while holding the heap lock. VM
230 // operations also hold the heap lock during collections. There is a lock
231 // contention case where thread A blocks waiting on the Heap_lock, while
232 // thread B is holding it doing a collection. When thread A gets the lock,
233 // the collection count has already changed. To prevent duplicate collections,
234 // The policy MUST attempt allocations during the same period it reads the
235 // total_collections() value!
236 {
237 MutexLocker ml(Heap_lock);
238 gc_count = total_collections();
239
240 result = young_gen()->allocate(size);
241 if (result != NULL) {
242 return result;
243 }
244
245 // If certain conditions hold, try allocating from the old gen.
246 result = mem_allocate_old_gen(size);
247 if (result != NULL) {
248 return result;
249 }
250
251 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
252 return NULL;
253 }
254
255 // Failed to allocate without a gc.
256 if (GCLocker::is_active_and_needs_gc()) {
257 // If this thread is not in a jni critical section, we stall
258 // the requestor until the critical section has cleared and
259 // GC allowed. When the critical section clears, a GC is
260 // initiated by the last thread exiting the critical section; so
261 // we retry the allocation sequence from the beginning of the loop,
262 // rather than causing more, now probably unnecessary, GC attempts.
263 JavaThread* jthr = JavaThread::current();
264 if (!jthr->in_critical()) {
265 MutexUnlocker mul(Heap_lock);
266 GCLocker::stall_until_clear();
267 gclocker_stalled_count += 1;
268 continue;
269 } else {
270 if (CheckJNICalls) {
271 fatal("Possible deadlock due to allocating while"
272 " in jni critical section");
273 }
274 return NULL;
275 }
276 }
277 }
278
279 if (result == NULL) {
280 // Generate a VM operation
281 VM_ParallelGCFailedAllocation op(size, gc_count);
282 VMThread::execute(&op);
283
284 // Did the VM operation execute? If so, return the result directly.
285 // This prevents us from looping until time out on requests that can
286 // not be satisfied.
287 if (op.prologue_succeeded()) {
288 assert(is_in_or_null(op.result()), "result not in heap");
289
290 // If GC was locked out during VM operation then retry allocation
291 // and/or stall as necessary.
292 if (op.gc_locked()) {
293 assert(op.result() == NULL, "must be NULL if gc_locked() is true");
294 continue; // retry and/or stall as necessary
295 }
296
297 // Exit the loop if the gc time limit has been exceeded.
298 // The allocation must have failed above ("result" guarding
299 // this path is NULL) and the most recent collection has exceeded the
300 // gc overhead limit (although enough may have been collected to
301 // satisfy the allocation). Exit the loop so that an out-of-memory
302 // will be thrown (return a NULL ignoring the contents of
303 // op.result()),
304 // but clear gc_overhead_limit_exceeded so that the next collection
305 // starts with a clean slate (i.e., forgets about previous overhead
306 // excesses). Fill op.result() with a filler object so that the
307 // heap remains parsable.
308 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
309 const bool softrefs_clear = collector_policy()->all_soft_refs_clear();
310
311 if (limit_exceeded && softrefs_clear) {
312 *gc_overhead_limit_was_exceeded = true;
313 size_policy()->set_gc_overhead_limit_exceeded(false);
314 log_trace(gc)("ParallelScavengeHeap::mem_allocate: return NULL because gc_overhead_limit_exceeded is set");
315 if (op.result() != NULL) {
316 CollectedHeap::fill_with_object(op.result(), size);
317 }
318 return NULL;
319 }
320
321 return op.result();
322 }
323 }
324
325 // The policy object will prevent us from looping forever. If the
326 // time spent in gc crosses a threshold, we will bail out.
327 loop_count++;
328 if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
329 (loop_count % QueuedAllocationWarningCount == 0)) {
330 log_warning(gc)("ParallelScavengeHeap::mem_allocate retries %d times", loop_count);
331 log_warning(gc)("\tsize=" SIZE_FORMAT, size);
332 }
333 }
334
335 return result;
336 }
337
338 // A "death march" is a series of ultra-slow allocations in which a full gc is
339 // done before each allocation, and after the full gc the allocation still
340 // cannot be satisfied from the young gen. This routine detects that condition;
341 // it should be called after a full gc has been done and the allocation
342 // attempted from the young gen. The parameter 'addr' should be the result of
343 // that young gen allocation attempt.
344 void
345 ParallelScavengeHeap::death_march_check(HeapWord* const addr, size_t size) {
346 if (addr != NULL) {
347 _death_march_count = 0; // death march has ended
348 } else if (_death_march_count == 0) {
349 if (should_alloc_in_eden(size)) {
350 _death_march_count = 1; // death march has started
351 }
352 }
353 }
354
355 HeapWord* ParallelScavengeHeap::mem_allocate_old_gen(size_t size) {
356 if (!should_alloc_in_eden(size) || GCLocker::is_active_and_needs_gc()) {
357 // Size is too big for eden, or gc is locked out.
358 return old_gen()->allocate(size);
359 }
360
361 // If a "death march" is in progress, allocate from the old gen a limited
362 // number of times before doing a GC.
363 if (_death_march_count > 0) {
364 if (_death_march_count < 64) {
365 ++_death_march_count;
366 return old_gen()->allocate(size);
367 } else {
368 _death_march_count = 0;
369 }
370 }
371 return NULL;
372 }
373
374 void ParallelScavengeHeap::do_full_collection(bool clear_all_soft_refs) {
375 if (UseParallelOldGC) {
376 // The do_full_collection() parameter clear_all_soft_refs
377 // is interpreted here as maximum_compaction which will
378 // cause SoftRefs to be cleared.
379 bool maximum_compaction = clear_all_soft_refs;
380 PSParallelCompact::invoke(maximum_compaction);
381 } else {
382 PSMarkSweep::invoke(clear_all_soft_refs);
383 }
384 }
385
386 // Failed allocation policy. Must be called from the VM thread, and
387 // only at a safepoint! Note that this method has policy for allocation
388 // flow, and NOT collection policy. So we do not check for gc collection
389 // time over limit here, that is the responsibility of the heap specific
390 // collection methods. This method decides where to attempt allocations,
391 // and when to attempt collections, but no collection specific policy.
392 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size) {
393 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
394 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
395 assert(!is_gc_active(), "not reentrant");
396 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
397
398 // We assume that allocation in eden will fail unless we collect.
399
400 // First level allocation failure, scavenge and allocate in young gen.
401 GCCauseSetter gccs(this, GCCause::_allocation_failure);
402 const bool invoked_full_gc = PSScavenge::invoke();
403 HeapWord* result = young_gen()->allocate(size);
404
405 // Second level allocation failure.
406 // Mark sweep and allocate in young generation.
407 if (result == NULL && !invoked_full_gc) {
408 do_full_collection(false);
409 result = young_gen()->allocate(size);
410 }
411
412 death_march_check(result, size);
413
414 // Third level allocation failure.
415 // After mark sweep and young generation allocation failure,
416 // allocate in old generation.
417 if (result == NULL) {
418 result = old_gen()->allocate(size);
419 }
420
421 // Fourth level allocation failure. We're running out of memory.
422 // More complete mark sweep and allocate in young generation.
423 if (result == NULL) {
424 do_full_collection(true);
425 result = young_gen()->allocate(size);
426 }
427
428 // Fifth level allocation failure.
429 // After more complete mark sweep, allocate in old generation.
430 if (result == NULL) {
431 result = old_gen()->allocate(size);
432 }
433
434 return result;
435 }
436
437 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
438 CollectedHeap::ensure_parsability(retire_tlabs);
439 young_gen()->eden_space()->ensure_parsability();
440 }
441
442 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
443 return young_gen()->eden_space()->tlab_capacity(thr);
444 }
445
446 size_t ParallelScavengeHeap::tlab_used(Thread* thr) const {
447 return young_gen()->eden_space()->tlab_used(thr);
448 }
449
450 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
451 return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
452 }
453
454 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
455 return young_gen()->allocate(size);
456 }
457
458 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
459 CollectedHeap::accumulate_statistics_all_tlabs();
460 }
461
462 void ParallelScavengeHeap::resize_all_tlabs() {
463 CollectedHeap::resize_all_tlabs();
464 }
465
466 bool ParallelScavengeHeap::can_elide_initializing_store_barrier(oop new_obj) {
467 // We don't need barriers for stores to objects in the
468 // young gen and, a fortiori, for initializing stores to
469 // objects therein.
470 return is_in_young(new_obj);
471 }
472
473 // This method is used by System.gc() and JVMTI.
474 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
475 assert(!Heap_lock->owned_by_self(),
476 "this thread should not own the Heap_lock");
477
478 uint gc_count = 0;
479 uint full_gc_count = 0;
480 {
481 MutexLocker ml(Heap_lock);
482 // This value is guarded by the Heap_lock
483 gc_count = total_collections();
484 full_gc_count = total_full_collections();
485 }
486
487 VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
488 VMThread::execute(&op);
489 }
490
491 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
492 young_gen()->object_iterate(cl);
493 old_gen()->object_iterate(cl);
494 }
495
496
497 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
498 if (young_gen()->is_in_reserved(addr)) {
499 assert(young_gen()->is_in(addr),
500 "addr should be in allocated part of young gen");
501 // called from os::print_location by find or VMError
502 if (Debugging || VMError::fatal_error_in_progress()) return NULL;
503 Unimplemented();
504 } else if (old_gen()->is_in_reserved(addr)) {
505 assert(old_gen()->is_in(addr),
506 "addr should be in allocated part of old gen");
507 return old_gen()->start_array()->object_start((HeapWord*)addr);
508 }
509 return 0;
510 }
511
512 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
513 return oop(addr)->size();
514 }
515
516 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
517 return block_start(addr) == addr;
518 }
519
520 jlong ParallelScavengeHeap::millis_since_last_gc() {
521 return UseParallelOldGC ?
522 PSParallelCompact::millis_since_last_gc() :
523 PSMarkSweep::millis_since_last_gc();
524 }
525
526 void ParallelScavengeHeap::prepare_for_verify() {
527 ensure_parsability(false); // no need to retire TLABs for verification
528 }
529
530 PSHeapSummary ParallelScavengeHeap::create_ps_heap_summary() {
531 PSOldGen* old = old_gen();
532 HeapWord* old_committed_end = (HeapWord*)old->virtual_space()->committed_high_addr();
533 VirtualSpaceSummary old_summary(old->reserved().start(), old_committed_end, old->reserved().end());
534 SpaceSummary old_space(old->reserved().start(), old_committed_end, old->used_in_bytes());
535
536 PSYoungGen* young = young_gen();
537 VirtualSpaceSummary young_summary(young->reserved().start(),
538 (HeapWord*)young->virtual_space()->committed_high_addr(), young->reserved().end());
539
540 MutableSpace* eden = young_gen()->eden_space();
541 SpaceSummary eden_space(eden->bottom(), eden->end(), eden->used_in_bytes());
542
543 MutableSpace* from = young_gen()->from_space();
544 SpaceSummary from_space(from->bottom(), from->end(), from->used_in_bytes());
545
546 MutableSpace* to = young_gen()->to_space();
547 SpaceSummary to_space(to->bottom(), to->end(), to->used_in_bytes());
548
549 VirtualSpaceSummary heap_summary = create_heap_space_summary();
550 return PSHeapSummary(heap_summary, used(), old_summary, old_space, young_summary, eden_space, from_space, to_space);
551 }
552
553 void ParallelScavengeHeap::print_on(outputStream* st) const {
554 young_gen()->print_on(st);
555 old_gen()->print_on(st);
556 MetaspaceAux::print_on(st);
557 }
558
559 void ParallelScavengeHeap::print_on_error(outputStream* st) const {
560 this->CollectedHeap::print_on_error(st);
561
562 if (UseParallelOldGC) {
563 st->cr();
564 PSParallelCompact::print_on_error(st);
565 }
566 }
567
568 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
569 PSScavenge::gc_task_manager()->threads_do(tc);
570 }
571
572 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
573 PSScavenge::gc_task_manager()->print_threads_on(st);
574 }
575
576 void ParallelScavengeHeap::print_tracing_info() const {
577 AdaptiveSizePolicyOutput::print();
578 log_debug(gc, heap, exit)("Accumulated young generation GC time %3.7f secs", PSScavenge::accumulated_time()->seconds());
579 log_debug(gc, heap, exit)("Accumulated old generation GC time %3.7f secs",
580 UseParallelOldGC ? PSParallelCompact::accumulated_time()->seconds() : PSMarkSweep::accumulated_time()->seconds());
581 }
582
583
584 void ParallelScavengeHeap::verify(VerifyOption option /* ignored */) {
585 // Why do we need the total_collections()-filter below?
586 if (total_collections() > 0) {
587 log_debug(gc, verify)("Tenured");
588 old_gen()->verify();
589
590 log_debug(gc, verify)("Eden");
591 young_gen()->verify();
592 }
593 }
594
595 void ParallelScavengeHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
596 const PSHeapSummary& heap_summary = create_ps_heap_summary();
597 gc_tracer->report_gc_heap_summary(when, heap_summary);
598
599 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
600 gc_tracer->report_metaspace_summary(when, metaspace_summary);
601 }
602
603 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
604 CollectedHeap* heap = Universe::heap();
605 assert(heap != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
606 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Not a ParallelScavengeHeap");
607 return (ParallelScavengeHeap*)heap;
608 }
609
610 // Before delegating the resize to the young generation,
611 // the reserved space for the young and old generations
612 // may be changed to accommodate the desired resize.
613 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
614 size_t survivor_size) {
615 if (UseAdaptiveGCBoundary) {
616 if (size_policy()->bytes_absorbed_from_eden() != 0) {
617 size_policy()->reset_bytes_absorbed_from_eden();
618 return; // The generation changed size already.
619 }
620 gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
621 }
622
623 // Delegate the resize to the generation.
624 _young_gen->resize(eden_size, survivor_size);
625 }
626
627 // Before delegating the resize to the old generation,
628 // the reserved space for the young and old generations
629 // may be changed to accommodate the desired resize.
630 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
631 if (UseAdaptiveGCBoundary) {
632 if (size_policy()->bytes_absorbed_from_eden() != 0) {
633 size_policy()->reset_bytes_absorbed_from_eden();
634 return; // The generation changed size already.
635 }
636 gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
637 }
638
639 // Delegate the resize to the generation.
640 _old_gen->resize(desired_free_space);
641 }
642
643 ParallelScavengeHeap::ParStrongRootsScope::ParStrongRootsScope() {
644 // nothing particular
645 }
646
647 ParallelScavengeHeap::ParStrongRootsScope::~ParStrongRootsScope() {
648 // nothing particular
649 }
650
651 #ifndef PRODUCT
652 void ParallelScavengeHeap::record_gen_tops_before_GC() {
653 if (ZapUnusedHeapArea) {
654 young_gen()->record_spaces_top();
655 old_gen()->record_spaces_top();
656 }
657 }
658
659 void ParallelScavengeHeap::gen_mangle_unused_area() {
660 if (ZapUnusedHeapArea) {
661 young_gen()->eden_space()->mangle_unused_area();
662 young_gen()->to_space()->mangle_unused_area();
663 young_gen()->from_space()->mangle_unused_area();
664 old_gen()->object_space()->mangle_unused_area();
665 }
666 }
667 #endif