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("ps main", _collector_policy->min_heap_byte_size(),
64 heap_size, generation_alignment(),
65 heap_rs.base(),
66 heap_rs.size());
67
68 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
69
70 CardTableExtension* const barrier_set = new CardTableExtension(reserved_region());
71 barrier_set->initialize();
72 set_barrier_set(barrier_set);
73
74 // Make up the generations
75 // Calculate the maximum size that a generation can grow. This
76 // includes growth into the other generation. Note that the
77 // parameter _max_gen_size is kept as the maximum
78 // size of the generation as the boundaries currently stand.
79 // _max_gen_size is still used as that value.
80 double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
81 double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
82
83 _gens = new AdjoiningGenerations(heap_rs, _collector_policy, generation_alignment());
84
85 _old_gen = _gens->old_gen();
86 _young_gen = _gens->young_gen();
87
88 const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
89 const size_t old_capacity = _old_gen->capacity_in_bytes();
90 const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
91 _size_policy =
92 new PSAdaptiveSizePolicy(eden_capacity,
93 initial_promo_size,
94 young_gen()->to_space()->capacity_in_bytes(),
95 _collector_policy->gen_alignment(),
96 max_gc_pause_sec,
97 max_gc_minor_pause_sec,
98 GCTimeRatio
99 );
100
101 assert(!UseAdaptiveGCBoundary ||
102 (old_gen()->virtual_space()->high_boundary() ==
103 young_gen()->virtual_space()->low_boundary()),
104 "Boundaries must meet");
105 // initialize the policy counters - 2 collectors, 3 generations
106 _gc_policy_counters =
107 new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
108
109 // Set up the GCTaskManager
110 _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
111
112 if (UseParallelOldGC && !PSParallelCompact::initialize()) {
113 return JNI_ENOMEM;
114 }
115
116 return JNI_OK;
117 }
118
119 void ParallelScavengeHeap::post_initialize() {
120 // Need to init the tenuring threshold
121 PSScavenge::initialize();
122 if (UseParallelOldGC) {
123 PSParallelCompact::post_initialize();
124 } else {
125 PSMarkSweep::initialize();
126 }
127 PSPromotionManager::initialize();
128 }
129
130 void ParallelScavengeHeap::update_counters() {
131 young_gen()->update_counters();
132 old_gen()->update_counters();
133 MetaspaceCounters::update_performance_counters();
134 CompressedClassSpaceCounters::update_performance_counters();
135 }
136
137 size_t ParallelScavengeHeap::capacity() const {
138 size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
139 return value;
140 }
141
142 size_t ParallelScavengeHeap::used() const {
143 size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
144 return value;
145 }
146
147 bool ParallelScavengeHeap::is_maximal_no_gc() const {
148 return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
149 }
150
151
152 size_t ParallelScavengeHeap::max_capacity() const {
153 size_t estimated = reserved_region().byte_size();
154 if (UseAdaptiveSizePolicy) {
155 estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
156 } else {
157 estimated -= young_gen()->to_space()->capacity_in_bytes();
158 }
159 return MAX2(estimated, capacity());
160 }
161
162 bool ParallelScavengeHeap::is_in(const void* p) const {
163 return young_gen()->is_in(p) || old_gen()->is_in(p);
164 }
165
166 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
167 return young_gen()->is_in_reserved(p) || old_gen()->is_in_reserved(p);
168 }
169
170 bool ParallelScavengeHeap::is_scavengable(const void* addr) {
171 return is_in_young((oop)addr);
172 }
173
174 // There are two levels of allocation policy here.
175 //
176 // When an allocation request fails, the requesting thread must invoke a VM
177 // operation, transfer control to the VM thread, and await the results of a
178 // garbage collection. That is quite expensive, and we should avoid doing it
179 // multiple times if possible.
180 //
181 // To accomplish this, we have a basic allocation policy, and also a
182 // failed allocation policy.
183 //
184 // The basic allocation policy controls how you allocate memory without
185 // attempting garbage collection. It is okay to grab locks and
186 // expand the heap, if that can be done without coming to a safepoint.
187 // It is likely that the basic allocation policy will not be very
188 // aggressive.
189 //
190 // The failed allocation policy is invoked from the VM thread after
191 // the basic allocation policy is unable to satisfy a mem_allocate
192 // request. This policy needs to cover the entire range of collection,
193 // heap expansion, and out-of-memory conditions. It should make every
194 // attempt to allocate the requested memory.
195
196 // Basic allocation policy. Should never be called at a safepoint, or
197 // from the VM thread.
198 //
199 // This method must handle cases where many mem_allocate requests fail
200 // simultaneously. When that happens, only one VM operation will succeed,
201 // and the rest will not be executed. For that reason, this method loops
202 // during failed allocation attempts. If the java heap becomes exhausted,
203 // we rely on the size_policy object to force a bail out.
204 HeapWord* ParallelScavengeHeap::mem_allocate(
205 size_t size,
206 bool* gc_overhead_limit_was_exceeded) {
207 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
208 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
209 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
210
211 // In general gc_overhead_limit_was_exceeded should be false so
212 // set it so here and reset it to true only if the gc time
213 // limit is being exceeded as checked below.
214 *gc_overhead_limit_was_exceeded = false;
215
216 HeapWord* result = young_gen()->allocate(size);
217
218 uint loop_count = 0;
219 uint gc_count = 0;
220 uint gclocker_stalled_count = 0;
221
222 while (result == NULL) {
223 // We don't want to have multiple collections for a single filled generation.
224 // To prevent this, each thread tracks the total_collections() value, and if
225 // the count has changed, does not do a new collection.
226 //
227 // The collection count must be read only while holding the heap lock. VM
228 // operations also hold the heap lock during collections. There is a lock
229 // contention case where thread A blocks waiting on the Heap_lock, while
230 // thread B is holding it doing a collection. When thread A gets the lock,
231 // the collection count has already changed. To prevent duplicate collections,
232 // The policy MUST attempt allocations during the same period it reads the
233 // total_collections() value!
234 {
235 MutexLocker ml(Heap_lock);
236 gc_count = total_collections();
237
238 result = young_gen()->allocate(size);
239 if (result != NULL) {
240 return result;
241 }
242
243 // If certain conditions hold, try allocating from the old gen.
244 result = mem_allocate_old_gen(size);
245 if (result != NULL) {
246 return result;
247 }
248
249 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
250 return NULL;
251 }
252
253 // Failed to allocate without a gc.
254 if (GCLocker::is_active_and_needs_gc()) {
255 // If this thread is not in a jni critical section, we stall
256 // the requestor until the critical section has cleared and
257 // GC allowed. When the critical section clears, a GC is
258 // initiated by the last thread exiting the critical section; so
259 // we retry the allocation sequence from the beginning of the loop,
260 // rather than causing more, now probably unnecessary, GC attempts.
261 JavaThread* jthr = JavaThread::current();
262 if (!jthr->in_critical()) {
263 MutexUnlocker mul(Heap_lock);
264 GCLocker::stall_until_clear();
265 gclocker_stalled_count += 1;
266 continue;
267 } else {
268 if (CheckJNICalls) {
269 fatal("Possible deadlock due to allocating while"
270 " in jni critical section");
271 }
272 return NULL;
273 }
274 }
275 }
276
277 if (result == NULL) {
278 // Generate a VM operation
279 VM_ParallelGCFailedAllocation op(size, gc_count);
280 VMThread::execute(&op);
281
282 // Did the VM operation execute? If so, return the result directly.
283 // This prevents us from looping until time out on requests that can
284 // not be satisfied.
285 if (op.prologue_succeeded()) {
286 assert(is_in_or_null(op.result()), "result not in heap");
287
288 // If GC was locked out during VM operation then retry allocation
289 // and/or stall as necessary.
290 if (op.gc_locked()) {
291 assert(op.result() == NULL, "must be NULL if gc_locked() is true");
292 continue; // retry and/or stall as necessary
293 }
294
295 // Exit the loop if the gc time limit has been exceeded.
296 // The allocation must have failed above ("result" guarding
297 // this path is NULL) and the most recent collection has exceeded the
298 // gc overhead limit (although enough may have been collected to
299 // satisfy the allocation). Exit the loop so that an out-of-memory
300 // will be thrown (return a NULL ignoring the contents of
301 // op.result()),
302 // but clear gc_overhead_limit_exceeded so that the next collection
303 // starts with a clean slate (i.e., forgets about previous overhead
304 // excesses). Fill op.result() with a filler object so that the
305 // heap remains parsable.
306 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
307 const bool softrefs_clear = collector_policy()->all_soft_refs_clear();
308
309 if (limit_exceeded && softrefs_clear) {
310 *gc_overhead_limit_was_exceeded = true;
311 size_policy()->set_gc_overhead_limit_exceeded(false);
312 log_trace(gc)("ParallelScavengeHeap::mem_allocate: return NULL because gc_overhead_limit_exceeded is set");
313 if (op.result() != NULL) {
314 CollectedHeap::fill_with_object(op.result(), size);
315 }
316 return NULL;
317 }
318
319 return op.result();
320 }
321 }
322
323 // The policy object will prevent us from looping forever. If the
324 // time spent in gc crosses a threshold, we will bail out.
325 loop_count++;
326 if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
327 (loop_count % QueuedAllocationWarningCount == 0)) {
328 log_warning(gc)("ParallelScavengeHeap::mem_allocate retries %d times", loop_count);
329 log_warning(gc)("\tsize=" SIZE_FORMAT, size);
330 }
331 }
332
333 return result;
334 }
335
336 // A "death march" is a series of ultra-slow allocations in which a full gc is
337 // done before each allocation, and after the full gc the allocation still
338 // cannot be satisfied from the young gen. This routine detects that condition;
339 // it should be called after a full gc has been done and the allocation
340 // attempted from the young gen. The parameter 'addr' should be the result of
341 // that young gen allocation attempt.
342 void
343 ParallelScavengeHeap::death_march_check(HeapWord* const addr, size_t size) {
344 if (addr != NULL) {
345 _death_march_count = 0; // death march has ended
346 } else if (_death_march_count == 0) {
347 if (should_alloc_in_eden(size)) {
348 _death_march_count = 1; // death march has started
349 }
350 }
351 }
352
353 HeapWord* ParallelScavengeHeap::mem_allocate_old_gen(size_t size) {
354 if (!should_alloc_in_eden(size) || GCLocker::is_active_and_needs_gc()) {
355 // Size is too big for eden, or gc is locked out.
356 return old_gen()->allocate(size);
357 }
358
359 // If a "death march" is in progress, allocate from the old gen a limited
360 // number of times before doing a GC.
361 if (_death_march_count > 0) {
362 if (_death_march_count < 64) {
363 ++_death_march_count;
364 return old_gen()->allocate(size);
365 } else {
366 _death_march_count = 0;
367 }
368 }
369 return NULL;
370 }
371
372 void ParallelScavengeHeap::do_full_collection(bool clear_all_soft_refs) {
373 if (UseParallelOldGC) {
374 // The do_full_collection() parameter clear_all_soft_refs
375 // is interpreted here as maximum_compaction which will
376 // cause SoftRefs to be cleared.
377 bool maximum_compaction = clear_all_soft_refs;
378 PSParallelCompact::invoke(maximum_compaction);
379 } else {
380 PSMarkSweep::invoke(clear_all_soft_refs);
381 }
382 }
383
384 // Failed allocation policy. Must be called from the VM thread, and
385 // only at a safepoint! Note that this method has policy for allocation
386 // flow, and NOT collection policy. So we do not check for gc collection
387 // time over limit here, that is the responsibility of the heap specific
388 // collection methods. This method decides where to attempt allocations,
389 // and when to attempt collections, but no collection specific policy.
390 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size) {
391 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
392 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
393 assert(!is_gc_active(), "not reentrant");
394 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
395
396 // We assume that allocation in eden will fail unless we collect.
397
398 // First level allocation failure, scavenge and allocate in young gen.
399 GCCauseSetter gccs(this, GCCause::_allocation_failure);
400 const bool invoked_full_gc = PSScavenge::invoke();
401 HeapWord* result = young_gen()->allocate(size);
402
403 // Second level allocation failure.
404 // Mark sweep and allocate in young generation.
405 if (result == NULL && !invoked_full_gc) {
406 do_full_collection(false);
407 result = young_gen()->allocate(size);
408 }
409
410 death_march_check(result, size);
411
412 // Third level allocation failure.
413 // After mark sweep and young generation allocation failure,
414 // allocate in old generation.
415 if (result == NULL) {
416 result = old_gen()->allocate(size);
417 }
418
419 // Fourth level allocation failure. We're running out of memory.
420 // More complete mark sweep and allocate in young generation.
421 if (result == NULL) {
422 do_full_collection(true);
423 result = young_gen()->allocate(size);
424 }
425
426 // Fifth level allocation failure.
427 // After more complete mark sweep, allocate in old generation.
428 if (result == NULL) {
429 result = old_gen()->allocate(size);
430 }
431
432 return result;
433 }
434
435 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
436 CollectedHeap::ensure_parsability(retire_tlabs);
437 young_gen()->eden_space()->ensure_parsability();
438 }
439
440 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
441 return young_gen()->eden_space()->tlab_capacity(thr);
442 }
443
444 size_t ParallelScavengeHeap::tlab_used(Thread* thr) const {
445 return young_gen()->eden_space()->tlab_used(thr);
446 }
447
448 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
449 return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
450 }
451
452 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
453 return young_gen()->allocate(size);
454 }
455
456 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
457 CollectedHeap::accumulate_statistics_all_tlabs();
458 }
459
460 void ParallelScavengeHeap::resize_all_tlabs() {
461 CollectedHeap::resize_all_tlabs();
462 }
463
464 bool ParallelScavengeHeap::can_elide_initializing_store_barrier(oop new_obj) {
465 // We don't need barriers for stores to objects in the
466 // young gen and, a fortiori, for initializing stores to
467 // objects therein.
468 return is_in_young(new_obj);
469 }
470
471 // This method is used by System.gc() and JVMTI.
472 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
473 assert(!Heap_lock->owned_by_self(),
474 "this thread should not own the Heap_lock");
475
476 uint gc_count = 0;
477 uint full_gc_count = 0;
478 {
479 MutexLocker ml(Heap_lock);
480 // This value is guarded by the Heap_lock
481 gc_count = total_collections();
482 full_gc_count = total_full_collections();
483 }
484
485 VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
486 VMThread::execute(&op);
487 }
488
489 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
490 young_gen()->object_iterate(cl);
491 old_gen()->object_iterate(cl);
492 }
493
494
495 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
496 if (young_gen()->is_in_reserved(addr)) {
497 assert(young_gen()->is_in(addr),
498 "addr should be in allocated part of young gen");
499 // called from os::print_location by find or VMError
500 if (Debugging || VMError::fatal_error_in_progress()) return NULL;
501 Unimplemented();
502 } else if (old_gen()->is_in_reserved(addr)) {
503 assert(old_gen()->is_in(addr),
504 "addr should be in allocated part of old gen");
505 return old_gen()->start_array()->object_start((HeapWord*)addr);
506 }
507 return 0;
508 }
509
510 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
511 return oop(addr)->size();
512 }
513
514 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
515 return block_start(addr) == addr;
516 }
517
518 jlong ParallelScavengeHeap::millis_since_last_gc() {
519 return UseParallelOldGC ?
520 PSParallelCompact::millis_since_last_gc() :
521 PSMarkSweep::millis_since_last_gc();
522 }
523
524 void ParallelScavengeHeap::prepare_for_verify() {
525 ensure_parsability(false); // no need to retire TLABs for verification
526 }
527
528 PSHeapSummary ParallelScavengeHeap::create_ps_heap_summary() {
529 PSOldGen* old = old_gen();
530 HeapWord* old_committed_end = (HeapWord*)old->virtual_space()->committed_high_addr();
531 VirtualSpaceSummary old_summary(old->reserved().start(), old_committed_end, old->reserved().end());
532 SpaceSummary old_space(old->reserved().start(), old_committed_end, old->used_in_bytes());
533
534 PSYoungGen* young = young_gen();
535 VirtualSpaceSummary young_summary(young->reserved().start(),
536 (HeapWord*)young->virtual_space()->committed_high_addr(), young->reserved().end());
537
538 MutableSpace* eden = young_gen()->eden_space();
539 SpaceSummary eden_space(eden->bottom(), eden->end(), eden->used_in_bytes());
540
541 MutableSpace* from = young_gen()->from_space();
542 SpaceSummary from_space(from->bottom(), from->end(), from->used_in_bytes());
543
544 MutableSpace* to = young_gen()->to_space();
545 SpaceSummary to_space(to->bottom(), to->end(), to->used_in_bytes());
546
547 VirtualSpaceSummary heap_summary = create_heap_space_summary();
548 return PSHeapSummary(heap_summary, used(), old_summary, old_space, young_summary, eden_space, from_space, to_space);
549 }
550
551 void ParallelScavengeHeap::print_on(outputStream* st) const {
552 young_gen()->print_on(st);
553 old_gen()->print_on(st);
554 MetaspaceAux::print_on(st);
555 }
556
557 void ParallelScavengeHeap::print_on_error(outputStream* st) const {
558 this->CollectedHeap::print_on_error(st);
559
560 if (UseParallelOldGC) {
561 st->cr();
562 PSParallelCompact::print_on_error(st);
563 }
564 }
565
566 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
567 PSScavenge::gc_task_manager()->threads_do(tc);
568 }
569
570 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
571 PSScavenge::gc_task_manager()->print_threads_on(st);
572 }
573
574 void ParallelScavengeHeap::print_tracing_info() const {
575 if (TraceYoungGenTime) {
576 double time = PSScavenge::accumulated_time()->seconds();
577 tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
578 }
579 if (TraceOldGenTime) {
580 double time = UseParallelOldGC ? PSParallelCompact::accumulated_time()->seconds() : PSMarkSweep::accumulated_time()->seconds();
581 tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
582 }
583 }
584
585
586 void ParallelScavengeHeap::verify(VerifyOption option /* ignored */) {
587 // Why do we need the total_collections()-filter below?
588 if (total_collections() > 0) {
589 log_debug(gc, verify)("Tenured");
590 old_gen()->verify();
591
592 log_debug(gc, verify)("Eden");
593 young_gen()->verify();
594 }
595 }
596
597 void ParallelScavengeHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
598 const PSHeapSummary& heap_summary = create_ps_heap_summary();
599 gc_tracer->report_gc_heap_summary(when, heap_summary);
600
601 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
602 gc_tracer->report_metaspace_summary(when, metaspace_summary);
603 }
604
605 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
606 CollectedHeap* heap = Universe::heap();
607 assert(heap != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
608 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Not a ParallelScavengeHeap");
609 return (ParallelScavengeHeap*)heap;
610 }
611
612 // Before delegating the resize to the young generation,
613 // the reserved space for the young and old generations
614 // may be changed to accommodate the desired resize.
615 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
616 size_t survivor_size) {
617 if (UseAdaptiveGCBoundary) {
618 if (size_policy()->bytes_absorbed_from_eden() != 0) {
619 size_policy()->reset_bytes_absorbed_from_eden();
620 return; // The generation changed size already.
621 }
622 gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
623 }
624
625 // Delegate the resize to the generation.
626 _young_gen->resize(eden_size, survivor_size);
627 }
628
629 // Before delegating the resize to the old generation,
630 // the reserved space for the young and old generations
631 // may be changed to accommodate the desired resize.
632 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
633 if (UseAdaptiveGCBoundary) {
634 if (size_policy()->bytes_absorbed_from_eden() != 0) {
635 size_policy()->reset_bytes_absorbed_from_eden();
636 return; // The generation changed size already.
637 }
638 gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
639 }
640
641 // Delegate the resize to the generation.
642 _old_gen->resize(desired_free_space);
643 }
644
645 ParallelScavengeHeap::ParStrongRootsScope::ParStrongRootsScope() {
646 // nothing particular
647 }
648
649 ParallelScavengeHeap::ParStrongRootsScope::~ParStrongRootsScope() {
650 // nothing particular
651 }
652
653 #ifndef PRODUCT
654 void ParallelScavengeHeap::record_gen_tops_before_GC() {
655 if (ZapUnusedHeapArea) {
656 young_gen()->record_spaces_top();
657 old_gen()->record_spaces_top();
658 }
659 }
660
661 void ParallelScavengeHeap::gen_mangle_unused_area() {
662 if (ZapUnusedHeapArea) {
663 young_gen()->eden_space()->mangle_unused_area();
664 young_gen()->to_space()->mangle_unused_area();
665 young_gen()->from_space()->mangle_unused_area();
666 old_gen()->object_space()->mangle_unused_area();
667 }
668 }
669 #endif