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