1 /*
2 * Copyright (c) 2000, 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 "aot/aotLoader.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "gc/shared/collectedHeap.inline.hpp"
33 #include "gc/shared/collectorCounters.hpp"
34 #include "gc/shared/gcId.hpp"
35 #include "gc/shared/gcLocker.inline.hpp"
36 #include "gc/shared/gcTrace.hpp"
37 #include "gc/shared/gcTraceTime.inline.hpp"
38 #include "gc/shared/genCollectedHeap.hpp"
39 #include "gc/shared/genOopClosures.inline.hpp"
40 #include "gc/shared/generationSpec.hpp"
41 #include "gc/shared/space.hpp"
42 #include "gc/shared/strongRootsScope.hpp"
43 #include "gc/shared/vmGCOperations.hpp"
44 #include "gc/shared/workgroup.hpp"
45 #include "memory/filemap.hpp"
46 #include "memory/resourceArea.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "runtime/biasedLocking.hpp"
49 #include "runtime/fprofiler.hpp"
50 #include "runtime/handles.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/vmThread.hpp"
54 #include "services/management.hpp"
55 #include "services/memoryService.hpp"
56 #include "utilities/macros.hpp"
57 #include "utilities/stack.inline.hpp"
58 #include "utilities/vmError.hpp"
59 #if INCLUDE_ALL_GCS
60 #include "gc/cms/concurrentMarkSweepThread.hpp"
61 #include "gc/cms/vmCMSOperations.hpp"
62 #endif // INCLUDE_ALL_GCS
63
64 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
65
66 // The set of potentially parallel tasks in root scanning.
67 enum GCH_strong_roots_tasks {
68 GCH_PS_Universe_oops_do,
69 GCH_PS_JNIHandles_oops_do,
70 GCH_PS_ObjectSynchronizer_oops_do,
71 GCH_PS_FlatProfiler_oops_do,
72 GCH_PS_Management_oops_do,
73 GCH_PS_SystemDictionary_oops_do,
74 GCH_PS_ClassLoaderDataGraph_oops_do,
75 GCH_PS_jvmti_oops_do,
76 GCH_PS_CodeCache_oops_do,
77 GCH_PS_aot_oops_do,
78 GCH_PS_younger_gens,
79 // Leave this one last.
80 GCH_PS_NumElements
81 };
82
83 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
84 CollectedHeap(),
85 _rem_set(NULL),
86 _gen_policy(policy),
87 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
88 _full_collections_completed(0)
89 {
90 assert(policy != NULL, "Sanity check");
91 if (UseConcMarkSweepGC) {
92 _workers = new WorkGang("GC Thread", ParallelGCThreads,
93 /* are_GC_task_threads */true,
94 /* are_ConcurrentGC_threads */false);
95 _workers->initialize_workers();
96 } else {
97 // Serial GC does not use workers.
98 _workers = NULL;
99 }
100 }
101
102 jint GenCollectedHeap::initialize() {
103 CollectedHeap::pre_initialize();
104
105 // While there are no constraints in the GC code that HeapWordSize
106 // be any particular value, there are multiple other areas in the
107 // system which believe this to be true (e.g. oop->object_size in some
108 // cases incorrectly returns the size in wordSize units rather than
109 // HeapWordSize).
110 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
111
112 // Allocate space for the heap.
113
114 char* heap_address;
115 ReservedSpace heap_rs;
116
117 size_t heap_alignment = collector_policy()->heap_alignment();
118
119 heap_address = allocate(heap_alignment, &heap_rs);
120
121 if (!heap_rs.is_reserved()) {
122 vm_shutdown_during_initialization(
123 "Could not reserve enough space for object heap");
124 return JNI_ENOMEM;
125 }
126
127 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
128
129 _rem_set = new CardTableRS(reserved_region());
130 _rem_set->initialize();
131 CardTableModRefBS *bs = new CardTableModRefBS(_rem_set);
132 bs->initialize();
133 set_barrier_set(bs);
134
135 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false);
136 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, rem_set());
137 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size());
138
139 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false);
140 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, rem_set());
141 clear_incremental_collection_failed();
142
143 #if INCLUDE_ALL_GCS
144 // If we are running CMS, create the collector responsible
145 // for collecting the CMS generations.
146 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
147 bool success = create_cms_collector();
148 if (!success) return JNI_ENOMEM;
149 }
150 #endif // INCLUDE_ALL_GCS
151
152 return JNI_OK;
153 }
154
155 char* GenCollectedHeap::allocate(size_t alignment,
156 ReservedSpace* heap_rs){
157 // Now figure out the total size.
158 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
159 assert(alignment % pageSize == 0, "Must be");
160
161 GenerationSpec* young_spec = gen_policy()->young_gen_spec();
162 GenerationSpec* old_spec = gen_policy()->old_gen_spec();
163
164 // Check for overflow.
165 size_t total_reserved = young_spec->max_size() + old_spec->max_size();
166 if (total_reserved < young_spec->max_size()) {
167 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
168 "the maximum representable size");
169 }
170 assert(total_reserved % alignment == 0,
171 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
172 SIZE_FORMAT, total_reserved, alignment);
173
174 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
175
176 os::trace_page_sizes("Heap",
177 collector_policy()->min_heap_byte_size(),
178 total_reserved,
179 alignment,
180 heap_rs->base(),
181 heap_rs->size());
182
183 return heap_rs->base();
184 }
185
186 void GenCollectedHeap::post_initialize() {
187 ref_processing_init();
188 assert((_young_gen->kind() == Generation::DefNew) ||
189 (_young_gen->kind() == Generation::ParNew),
190 "Wrong youngest generation type");
191 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
192
193 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep ||
194 _old_gen->kind() == Generation::MarkSweepCompact,
195 "Wrong generation kind");
196
197 _gen_policy->initialize_size_policy(def_new_gen->eden()->capacity(),
198 _old_gen->capacity(),
199 def_new_gen->from()->capacity());
200 _gen_policy->initialize_gc_policy_counters();
201 }
202
203 void GenCollectedHeap::ref_processing_init() {
204 _young_gen->ref_processor_init();
205 _old_gen->ref_processor_init();
206 }
207
208 size_t GenCollectedHeap::capacity() const {
209 return _young_gen->capacity() + _old_gen->capacity();
210 }
211
212 size_t GenCollectedHeap::used() const {
213 return _young_gen->used() + _old_gen->used();
214 }
215
216 void GenCollectedHeap::save_used_regions() {
217 _old_gen->save_used_region();
218 _young_gen->save_used_region();
219 }
220
221 size_t GenCollectedHeap::max_capacity() const {
222 return _young_gen->max_capacity() + _old_gen->max_capacity();
223 }
224
225 // Update the _full_collections_completed counter
226 // at the end of a stop-world full GC.
227 unsigned int GenCollectedHeap::update_full_collections_completed() {
228 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
229 assert(_full_collections_completed <= _total_full_collections,
230 "Can't complete more collections than were started");
231 _full_collections_completed = _total_full_collections;
232 ml.notify_all();
233 return _full_collections_completed;
234 }
235
236 // Update the _full_collections_completed counter, as appropriate,
237 // at the end of a concurrent GC cycle. Note the conditional update
238 // below to allow this method to be called by a concurrent collector
239 // without synchronizing in any manner with the VM thread (which
240 // may already have initiated a STW full collection "concurrently").
241 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
242 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
243 assert((_full_collections_completed <= _total_full_collections) &&
244 (count <= _total_full_collections),
245 "Can't complete more collections than were started");
246 if (count > _full_collections_completed) {
247 _full_collections_completed = count;
248 ml.notify_all();
249 }
250 return _full_collections_completed;
251 }
252
253
254 #ifndef PRODUCT
255 // Override of memory state checking method in CollectedHeap:
256 // Some collectors (CMS for example) can't have badHeapWordVal written
257 // in the first two words of an object. (For instance , in the case of
258 // CMS these words hold state used to synchronize between certain
259 // (concurrent) GC steps and direct allocating mutators.)
260 // The skip_header_HeapWords() method below, allows us to skip
261 // over the requisite number of HeapWord's. Note that (for
262 // generational collectors) this means that those many words are
263 // skipped in each object, irrespective of the generation in which
264 // that object lives. The resultant loss of precision seems to be
265 // harmless and the pain of avoiding that imprecision appears somewhat
266 // higher than we are prepared to pay for such rudimentary debugging
267 // support.
268 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
269 size_t size) {
270 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
271 // We are asked to check a size in HeapWords,
272 // but the memory is mangled in juint words.
273 juint* start = (juint*) (addr + skip_header_HeapWords());
274 juint* end = (juint*) (addr + size);
275 for (juint* slot = start; slot < end; slot += 1) {
276 assert(*slot == badHeapWordVal,
277 "Found non badHeapWordValue in pre-allocation check");
278 }
279 }
280 }
281 #endif
282
283 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
284 bool is_tlab,
285 bool first_only) {
286 HeapWord* res = NULL;
287
288 if (_young_gen->should_allocate(size, is_tlab)) {
289 res = _young_gen->allocate(size, is_tlab);
290 if (res != NULL || first_only) {
291 return res;
292 }
293 }
294
295 if (_old_gen->should_allocate(size, is_tlab)) {
296 res = _old_gen->allocate(size, is_tlab);
297 }
298
299 return res;
300 }
301
302 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
303 bool* gc_overhead_limit_was_exceeded) {
304 return gen_policy()->mem_allocate_work(size,
305 false /* is_tlab */,
306 gc_overhead_limit_was_exceeded);
307 }
308
309 bool GenCollectedHeap::must_clear_all_soft_refs() {
310 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
311 _gc_cause == GCCause::_wb_full_gc;
312 }
313
314 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
315 if (!UseConcMarkSweepGC) {
316 return false;
317 }
318
319 switch (cause) {
320 case GCCause::_gc_locker: return GCLockerInvokesConcurrent;
321 case GCCause::_java_lang_system_gc:
322 case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent;
323 default: return false;
324 }
325 }
326
327 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
328 bool is_tlab, bool run_verification, bool clear_soft_refs,
329 bool restore_marks_for_biased_locking) {
330 FormatBuffer<> title("Collect gen: %s", gen->short_name());
331 GCTraceTime(Trace, gc, phases) t1(title);
332 TraceCollectorStats tcs(gen->counters());
333 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
334
335 gen->stat_record()->invocations++;
336 gen->stat_record()->accumulated_time.start();
337
338 // Must be done anew before each collection because
339 // a previous collection will do mangling and will
340 // change top of some spaces.
341 record_gen_tops_before_GC();
342
343 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
344
345 if (run_verification && VerifyBeforeGC) {
346 HandleMark hm; // Discard invalid handles created during verification
347 Universe::verify("Before GC");
348 }
349 COMPILER2_PRESENT(DerivedPointerTable::clear());
350
351 if (restore_marks_for_biased_locking) {
352 // We perform this mark word preservation work lazily
353 // because it's only at this point that we know whether we
354 // absolutely have to do it; we want to avoid doing it for
355 // scavenge-only collections where it's unnecessary
356 BiasedLocking::preserve_marks();
357 }
358
359 // Do collection work
360 {
361 // Note on ref discovery: For what appear to be historical reasons,
362 // GCH enables and disabled (by enqueing) refs discovery.
363 // In the future this should be moved into the generation's
364 // collect method so that ref discovery and enqueueing concerns
365 // are local to a generation. The collect method could return
366 // an appropriate indication in the case that notification on
367 // the ref lock was needed. This will make the treatment of
368 // weak refs more uniform (and indeed remove such concerns
369 // from GCH). XXX
370
371 HandleMark hm; // Discard invalid handles created during gc
372 save_marks(); // save marks for all gens
373 // We want to discover references, but not process them yet.
374 // This mode is disabled in process_discovered_references if the
375 // generation does some collection work, or in
376 // enqueue_discovered_references if the generation returns
377 // without doing any work.
378 ReferenceProcessor* rp = gen->ref_processor();
379 // If the discovery of ("weak") refs in this generation is
380 // atomic wrt other collectors in this configuration, we
381 // are guaranteed to have empty discovered ref lists.
382 if (rp->discovery_is_atomic()) {
383 rp->enable_discovery();
384 rp->setup_policy(clear_soft_refs);
385 } else {
386 // collect() below will enable discovery as appropriate
387 }
388 gen->collect(full, clear_soft_refs, size, is_tlab);
389 if (!rp->enqueuing_is_done()) {
390 rp->enqueue_discovered_references();
391 } else {
392 rp->set_enqueuing_is_done(false);
393 }
394 rp->verify_no_references_recorded();
395 }
396
397 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
398
399 gen->stat_record()->accumulated_time.stop();
400
401 update_gc_stats(gen, full);
402
403 if (run_verification && VerifyAfterGC) {
404 HandleMark hm; // Discard invalid handles created during verification
405 Universe::verify("After GC");
406 }
407 }
408
409 void GenCollectedHeap::do_collection(bool full,
410 bool clear_all_soft_refs,
411 size_t size,
412 bool is_tlab,
413 GenerationType max_generation) {
414 ResourceMark rm;
415 DEBUG_ONLY(Thread* my_thread = Thread::current();)
416
417 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
418 assert(my_thread->is_VM_thread() ||
419 my_thread->is_ConcurrentGC_thread(),
420 "incorrect thread type capability");
421 assert(Heap_lock->is_locked(),
422 "the requesting thread should have the Heap_lock");
423 guarantee(!is_gc_active(), "collection is not reentrant");
424
425 if (GCLocker::check_active_before_gc()) {
426 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
427 }
428
429 GCIdMarkAndRestore gc_id_mark;
430
431 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
432 collector_policy()->should_clear_all_soft_refs();
433
434 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
435
436 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
437
438 print_heap_before_gc();
439
440 {
441 FlagSetting fl(_is_gc_active, true);
442
443 bool complete = full && (max_generation == OldGen);
444 bool old_collects_young = complete && !ScavengeBeforeFullGC;
445 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
446
447 FormatBuffer<> gc_string("%s", "Pause ");
448 if (do_young_collection) {
449 gc_string.append("Young");
450 } else {
451 gc_string.append("Full");
452 }
453
454 GCTraceCPUTime tcpu;
455 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true);
456
457 gc_prologue(complete);
458 increment_total_collections(complete);
459
460 size_t young_prev_used = _young_gen->used();
461 size_t old_prev_used = _old_gen->used();
462
463 bool run_verification = total_collections() >= VerifyGCStartAt;
464
465 bool prepared_for_verification = false;
466 bool collected_old = false;
467
468 if (do_young_collection) {
469 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
470 prepare_for_verify();
471 prepared_for_verification = true;
472 }
473
474 collect_generation(_young_gen,
475 full,
476 size,
477 is_tlab,
478 run_verification && VerifyGCLevel <= 0,
479 do_clear_all_soft_refs,
480 false);
481
482 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
483 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
484 // Allocation request was met by young GC.
485 size = 0;
486 }
487 }
488
489 bool must_restore_marks_for_biased_locking = false;
490
491 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) {
492 if (!complete) {
493 // The full_collections increment was missed above.
494 increment_total_full_collections();
495 }
496
497 if (!prepared_for_verification && run_verification &&
498 VerifyGCLevel <= 1 && VerifyBeforeGC) {
499 prepare_for_verify();
500 }
501
502 if (do_young_collection) {
503 // We did a young GC. Need a new GC id for the old GC.
504 GCIdMarkAndRestore gc_id_mark;
505 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
506 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
507 } else {
508 // No young GC done. Use the same GC id as was set up earlier in this method.
509 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
510 }
511
512 must_restore_marks_for_biased_locking = true;
513 collected_old = true;
514 }
515
516 // Update "complete" boolean wrt what actually transpired --
517 // for instance, a promotion failure could have led to
518 // a whole heap collection.
519 complete = complete || collected_old;
520
521 print_heap_change(young_prev_used, old_prev_used);
522 MetaspaceAux::print_metaspace_change(metadata_prev_used);
523
524 // Adjust generation sizes.
525 if (collected_old) {
526 _old_gen->compute_new_size();
527 }
528 _young_gen->compute_new_size();
529
530 if (complete) {
531 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
532 ClassLoaderDataGraph::purge();
533 MetaspaceAux::verify_metrics();
534 // Resize the metaspace capacity after full collections
535 MetaspaceGC::compute_new_size();
536 update_full_collections_completed();
537 }
538
539 // Track memory usage and detect low memory after GC finishes
540 MemoryService::track_memory_usage();
541
542 gc_epilogue(complete);
543
544 if (must_restore_marks_for_biased_locking) {
545 BiasedLocking::restore_marks();
546 }
547 }
548
549 print_heap_after_gc();
550
551 #ifdef TRACESPINNING
552 ParallelTaskTerminator::print_termination_counts();
553 #endif
554 }
555
556 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
557 return gen_policy()->satisfy_failed_allocation(size, is_tlab);
558 }
559
560 #ifdef ASSERT
561 class AssertNonScavengableClosure: public OopClosure {
562 public:
563 virtual void do_oop(oop* p) {
564 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
565 "Referent should not be scavengable."); }
566 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
567 };
568 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
569 #endif
570
571 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
572 ScanningOption so,
573 OopClosure* strong_roots,
574 OopClosure* weak_roots,
575 CLDClosure* strong_cld_closure,
576 CLDClosure* weak_cld_closure,
577 CodeBlobToOopClosure* code_roots) {
578 // General roots.
579 assert(Threads::thread_claim_parity() != 0, "must have called prologue code");
580 assert(code_roots != NULL, "code root closure should always be set");
581 // _n_termination for _process_strong_tasks should be set up stream
582 // in a method not running in a GC worker. Otherwise the GC worker
583 // could be trying to change the termination condition while the task
584 // is executing in another GC worker.
585
586 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
587 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
588 }
589
590 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
591 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
592
593 bool is_par = scope->n_threads() > 1;
594 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
595
596 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
597 Universe::oops_do(strong_roots);
598 }
599 // Global (strong) JNI handles
600 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
601 JNIHandles::oops_do(strong_roots);
602 }
603
604 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
605 ObjectSynchronizer::oops_do(strong_roots);
606 }
607 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
608 FlatProfiler::oops_do(strong_roots);
609 }
610 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
611 Management::oops_do(strong_roots);
612 }
613 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
614 JvmtiExport::oops_do(strong_roots);
615 }
616 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) {
617 AOTLoader::oops_do(strong_roots);
618 }
619
620 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
621 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
622 }
623
624 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
625 if (so & SO_ScavengeCodeCache) {
626 assert(code_roots != NULL, "must supply closure for code cache");
627
628 // We only visit parts of the CodeCache when scavenging.
629 CodeCache::scavenge_root_nmethods_do(code_roots);
630 }
631 if (so & SO_AllCodeCache) {
632 assert(code_roots != NULL, "must supply closure for code cache");
633
634 // CMSCollector uses this to do intermediate-strength collections.
635 // We scan the entire code cache, since CodeCache::do_unloading is not called.
636 CodeCache::blobs_do(code_roots);
637 }
638 // Verify that the code cache contents are not subject to
639 // movement by a scavenging collection.
640 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
641 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
642 }
643 }
644
645 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope,
646 OopClosure* root_closure) {
647 assert(root_closure != NULL, "Must be set");
648 // All threads execute the following. A specific chunk of buckets
649 // from the StringTable are the individual tasks.
650 if (scope->n_threads() > 1) {
651 StringTable::possibly_parallel_oops_do(root_closure);
652 } else {
653 StringTable::oops_do(root_closure);
654 }
655 }
656
657 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
658 OopsInGenClosure* root_closure,
659 OopsInGenClosure* old_gen_closure,
660 CLDClosure* cld_closure) {
661 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
662
663 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure,
664 cld_closure, cld_closure, &mark_code_closure);
665 process_string_table_roots(scope, root_closure);
666
667 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
668 root_closure->reset_generation();
669 }
670
671 // When collection is parallel, all threads get to cooperate to do
672 // old generation scanning.
673 old_gen_closure->set_generation(_old_gen);
674 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
675 old_gen_closure->reset_generation();
676
677 _process_strong_tasks->all_tasks_completed(scope->n_threads());
678 }
679
680 void GenCollectedHeap::cms_process_roots(StrongRootsScope* scope,
681 bool young_gen_as_roots,
682 ScanningOption so,
683 bool only_strong_roots,
684 OopsInGenClosure* root_closure,
685 CLDClosure* cld_closure) {
686 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations);
687 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
688 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
689
690 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
691 if (!only_strong_roots) {
692 process_string_table_roots(scope, root_closure);
693 }
694
695 if (young_gen_as_roots &&
696 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
697 root_closure->set_generation(_young_gen);
698 _young_gen->oop_iterate(root_closure);
699 root_closure->reset_generation();
700 }
701
702 _process_strong_tasks->all_tasks_completed(scope->n_threads());
703 }
704
705 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
706 bool is_adjust_phase,
707 ScanningOption so,
708 bool only_strong_roots,
709 OopsInGenClosure* root_closure,
710 CLDClosure* cld_closure) {
711 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
712 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
713 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
714
715 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
716 if (is_adjust_phase) {
717 // We never treat the string table as roots during marking
718 // for the full gc, so we only need to process it during
719 // the adjust phase.
720 process_string_table_roots(scope, root_closure);
721 }
722
723 _process_strong_tasks->all_tasks_completed(scope->n_threads());
724 }
725
726 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
727 JNIHandles::weak_oops_do(root_closure);
728 _young_gen->ref_processor()->weak_oops_do(root_closure);
729 _old_gen->ref_processor()->weak_oops_do(root_closure);
730 }
731
732 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
733 void GenCollectedHeap:: \
734 oop_since_save_marks_iterate(GenerationType gen, \
735 OopClosureType* cur, \
736 OopClosureType* older) { \
737 if (gen == YoungGen) { \
738 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
739 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
740 } else { \
741 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
742 } \
743 }
744
745 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
746
747 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
748
749 bool GenCollectedHeap::no_allocs_since_save_marks() {
750 return _young_gen->no_allocs_since_save_marks() &&
751 _old_gen->no_allocs_since_save_marks();
752 }
753
754 bool GenCollectedHeap::supports_inline_contig_alloc() const {
755 return _young_gen->supports_inline_contig_alloc();
756 }
757
758 HeapWord* volatile* GenCollectedHeap::top_addr() const {
759 return _young_gen->top_addr();
760 }
761
762 HeapWord** GenCollectedHeap::end_addr() const {
763 return _young_gen->end_addr();
764 }
765
766 // public collection interfaces
767
768 void GenCollectedHeap::collect(GCCause::Cause cause) {
769 if (should_do_concurrent_full_gc(cause)) {
770 #if INCLUDE_ALL_GCS
771 // Mostly concurrent full collection.
772 collect_mostly_concurrent(cause);
773 #else // INCLUDE_ALL_GCS
774 ShouldNotReachHere();
775 #endif // INCLUDE_ALL_GCS
776 } else if (cause == GCCause::_wb_young_gc) {
777 // Young collection for the WhiteBox API.
778 collect(cause, YoungGen);
779 } else {
780 #ifdef ASSERT
781 if (cause == GCCause::_scavenge_alot) {
782 // Young collection only.
783 collect(cause, YoungGen);
784 } else {
785 // Stop-the-world full collection.
786 collect(cause, OldGen);
787 }
788 #else
789 // Stop-the-world full collection.
790 collect(cause, OldGen);
791 #endif
792 }
793 }
794
795 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
796 // The caller doesn't have the Heap_lock
797 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
798 MutexLocker ml(Heap_lock);
799 collect_locked(cause, max_generation);
800 }
801
802 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
803 // The caller has the Heap_lock
804 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
805 collect_locked(cause, OldGen);
806 }
807
808 // this is the private collection interface
809 // The Heap_lock is expected to be held on entry.
810
811 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
812 // Read the GC count while holding the Heap_lock
813 unsigned int gc_count_before = total_collections();
814 unsigned int full_gc_count_before = total_full_collections();
815 {
816 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
817 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
818 cause, max_generation);
819 VMThread::execute(&op);
820 }
821 }
822
823 #if INCLUDE_ALL_GCS
824 bool GenCollectedHeap::create_cms_collector() {
825
826 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
827 "Unexpected generation kinds");
828 // Skip two header words in the block content verification
829 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
830 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type");
831 CMSCollector* collector =
832 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen,
833 _rem_set,
834 _gen_policy->as_concurrent_mark_sweep_policy());
835
836 if (collector == NULL || !collector->completed_initialization()) {
837 if (collector) {
838 delete collector; // Be nice in embedded situation
839 }
840 vm_shutdown_during_initialization("Could not create CMS collector");
841 return false;
842 }
843 return true; // success
844 }
845
846 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
847 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
848
849 MutexLocker ml(Heap_lock);
850 // Read the GC counts while holding the Heap_lock
851 unsigned int full_gc_count_before = total_full_collections();
852 unsigned int gc_count_before = total_collections();
853 {
854 MutexUnlocker mu(Heap_lock);
855 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
856 VMThread::execute(&op);
857 }
858 }
859 #endif // INCLUDE_ALL_GCS
860
861 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
862 do_full_collection(clear_all_soft_refs, OldGen);
863 }
864
865 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
866 GenerationType last_generation) {
867 GenerationType local_last_generation;
868 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
869 gc_cause() == GCCause::_gc_locker) {
870 local_last_generation = YoungGen;
871 } else {
872 local_last_generation = last_generation;
873 }
874
875 do_collection(true, // full
876 clear_all_soft_refs, // clear_all_soft_refs
877 0, // size
878 false, // is_tlab
879 local_last_generation); // last_generation
880 // Hack XXX FIX ME !!!
881 // A scavenge may not have been attempted, or may have
882 // been attempted and failed, because the old gen was too full
883 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker &&
884 incremental_collection_will_fail(false /* don't consult_young */)) {
885 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
886 // This time allow the old gen to be collected as well
887 do_collection(true, // full
888 clear_all_soft_refs, // clear_all_soft_refs
889 0, // size
890 false, // is_tlab
891 OldGen); // last_generation
892 }
893 }
894
895 bool GenCollectedHeap::is_in_young(oop p) {
896 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
897 assert(result == _young_gen->is_in_reserved(p),
898 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
899 return result;
900 }
901
902 // Returns "TRUE" iff "p" points into the committed areas of the heap.
903 bool GenCollectedHeap::is_in(const void* p) const {
904 return _young_gen->is_in(p) || _old_gen->is_in(p);
905 }
906
907 #ifdef ASSERT
908 // Don't implement this by using is_in_young(). This method is used
909 // in some cases to check that is_in_young() is correct.
910 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
911 assert(is_in_reserved(p) || p == NULL,
912 "Does not work if address is non-null and outside of the heap");
913 return p < _young_gen->reserved().end() && p != NULL;
914 }
915 #endif
916
917 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) {
918 NoHeaderExtendedOopClosure no_header_cl(cl);
919 oop_iterate(&no_header_cl);
920 }
921
922 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
923 _young_gen->oop_iterate(cl);
924 _old_gen->oop_iterate(cl);
925 }
926
927 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
928 _young_gen->object_iterate(cl);
929 _old_gen->object_iterate(cl);
930 }
931
932 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
933 _young_gen->safe_object_iterate(cl);
934 _old_gen->safe_object_iterate(cl);
935 }
936
937 Space* GenCollectedHeap::space_containing(const void* addr) const {
938 Space* res = _young_gen->space_containing(addr);
939 if (res != NULL) {
940 return res;
941 }
942 res = _old_gen->space_containing(addr);
943 assert(res != NULL, "Could not find containing space");
944 return res;
945 }
946
947 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
948 assert(is_in_reserved(addr), "block_start of address outside of heap");
949 if (_young_gen->is_in_reserved(addr)) {
950 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
951 return _young_gen->block_start(addr);
952 }
953
954 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
955 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
956 return _old_gen->block_start(addr);
957 }
958
959 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
960 assert(is_in_reserved(addr), "block_size of address outside of heap");
961 if (_young_gen->is_in_reserved(addr)) {
962 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
963 return _young_gen->block_size(addr);
964 }
965
966 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
967 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
968 return _old_gen->block_size(addr);
969 }
970
971 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
972 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
973 assert(block_start(addr) == addr, "addr must be a block start");
974 if (_young_gen->is_in_reserved(addr)) {
975 return _young_gen->block_is_obj(addr);
976 }
977
978 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
979 return _old_gen->block_is_obj(addr);
980 }
981
982 bool GenCollectedHeap::supports_tlab_allocation() const {
983 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
984 return _young_gen->supports_tlab_allocation();
985 }
986
987 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
988 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
989 if (_young_gen->supports_tlab_allocation()) {
990 return _young_gen->tlab_capacity();
991 }
992 return 0;
993 }
994
995 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
996 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
997 if (_young_gen->supports_tlab_allocation()) {
998 return _young_gen->tlab_used();
999 }
1000 return 0;
1001 }
1002
1003 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1004 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1005 if (_young_gen->supports_tlab_allocation()) {
1006 return _young_gen->unsafe_max_tlab_alloc();
1007 }
1008 return 0;
1009 }
1010
1011 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1012 bool gc_overhead_limit_was_exceeded;
1013 return gen_policy()->mem_allocate_work(size /* size */,
1014 true /* is_tlab */,
1015 &gc_overhead_limit_was_exceeded);
1016 }
1017
1018 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1019 // from the list headed by "*prev_ptr".
1020 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1021 bool first = true;
1022 size_t min_size = 0; // "first" makes this conceptually infinite.
1023 ScratchBlock **smallest_ptr, *smallest;
1024 ScratchBlock *cur = *prev_ptr;
1025 while (cur) {
1026 assert(*prev_ptr == cur, "just checking");
1027 if (first || cur->num_words < min_size) {
1028 smallest_ptr = prev_ptr;
1029 smallest = cur;
1030 min_size = smallest->num_words;
1031 first = false;
1032 }
1033 prev_ptr = &cur->next;
1034 cur = cur->next;
1035 }
1036 smallest = *smallest_ptr;
1037 *smallest_ptr = smallest->next;
1038 return smallest;
1039 }
1040
1041 // Sort the scratch block list headed by res into decreasing size order,
1042 // and set "res" to the result.
1043 static void sort_scratch_list(ScratchBlock*& list) {
1044 ScratchBlock* sorted = NULL;
1045 ScratchBlock* unsorted = list;
1046 while (unsorted) {
1047 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1048 smallest->next = sorted;
1049 sorted = smallest;
1050 }
1051 list = sorted;
1052 }
1053
1054 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1055 size_t max_alloc_words) {
1056 ScratchBlock* res = NULL;
1057 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1058 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1059 sort_scratch_list(res);
1060 return res;
1061 }
1062
1063 void GenCollectedHeap::release_scratch() {
1064 _young_gen->reset_scratch();
1065 _old_gen->reset_scratch();
1066 }
1067
1068 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1069 void do_generation(Generation* gen) {
1070 gen->prepare_for_verify();
1071 }
1072 };
1073
1074 void GenCollectedHeap::prepare_for_verify() {
1075 ensure_parsability(false); // no need to retire TLABs
1076 GenPrepareForVerifyClosure blk;
1077 generation_iterate(&blk, false);
1078 }
1079
1080 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1081 bool old_to_young) {
1082 if (old_to_young) {
1083 cl->do_generation(_old_gen);
1084 cl->do_generation(_young_gen);
1085 } else {
1086 cl->do_generation(_young_gen);
1087 cl->do_generation(_old_gen);
1088 }
1089 }
1090
1091 bool GenCollectedHeap::is_maximal_no_gc() const {
1092 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1093 }
1094
1095 void GenCollectedHeap::save_marks() {
1096 _young_gen->save_marks();
1097 _old_gen->save_marks();
1098 }
1099
1100 GenCollectedHeap* GenCollectedHeap::heap() {
1101 CollectedHeap* heap = Universe::heap();
1102 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1103 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap");
1104 return (GenCollectedHeap*)heap;
1105 }
1106
1107 void GenCollectedHeap::prepare_for_compaction() {
1108 // Start by compacting into same gen.
1109 CompactPoint cp(_old_gen);
1110 _old_gen->prepare_for_compaction(&cp);
1111 _young_gen->prepare_for_compaction(&cp);
1112 }
1113
1114 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1115 log_debug(gc, verify)("%s", _old_gen->name());
1116 _old_gen->verify();
1117
1118 log_debug(gc, verify)("%s", _old_gen->name());
1119 _young_gen->verify();
1120
1121 log_debug(gc, verify)("RemSet");
1122 rem_set()->verify();
1123 }
1124
1125 void GenCollectedHeap::print_on(outputStream* st) const {
1126 _young_gen->print_on(st);
1127 _old_gen->print_on(st);
1128 MetaspaceAux::print_on(st);
1129 }
1130
1131 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1132 if (workers() != NULL) {
1133 workers()->threads_do(tc);
1134 }
1135 #if INCLUDE_ALL_GCS
1136 if (UseConcMarkSweepGC) {
1137 ConcurrentMarkSweepThread::threads_do(tc);
1138 }
1139 #endif // INCLUDE_ALL_GCS
1140 }
1141
1142 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1143 #if INCLUDE_ALL_GCS
1144 if (UseConcMarkSweepGC) {
1145 workers()->print_worker_threads_on(st);
1146 ConcurrentMarkSweepThread::print_all_on(st);
1147 }
1148 #endif // INCLUDE_ALL_GCS
1149 }
1150
1151 void GenCollectedHeap::print_on_error(outputStream* st) const {
1152 this->CollectedHeap::print_on_error(st);
1153
1154 #if INCLUDE_ALL_GCS
1155 if (UseConcMarkSweepGC) {
1156 st->cr();
1157 CMSCollector::print_on_error(st);
1158 }
1159 #endif // INCLUDE_ALL_GCS
1160 }
1161
1162 void GenCollectedHeap::print_tracing_info() const {
1163 if (TraceYoungGenTime) {
1164 _young_gen->print_summary_info();
1165 }
1166 if (TraceOldGenTime) {
1167 _old_gen->print_summary_info();
1168 }
1169 }
1170
1171 void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const {
1172 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1173 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K);
1174 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1175 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K);
1176 }
1177
1178 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1179 private:
1180 bool _full;
1181 public:
1182 void do_generation(Generation* gen) {
1183 gen->gc_prologue(_full);
1184 }
1185 GenGCPrologueClosure(bool full) : _full(full) {};
1186 };
1187
1188 void GenCollectedHeap::gc_prologue(bool full) {
1189 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1190
1191 always_do_update_barrier = false;
1192 // Fill TLAB's and such
1193 CollectedHeap::accumulate_statistics_all_tlabs();
1194 ensure_parsability(true); // retire TLABs
1195
1196 // Walk generations
1197 GenGCPrologueClosure blk(full);
1198 generation_iterate(&blk, false); // not old-to-young.
1199 };
1200
1201 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1202 private:
1203 bool _full;
1204 public:
1205 void do_generation(Generation* gen) {
1206 gen->gc_epilogue(_full);
1207 }
1208 GenGCEpilogueClosure(bool full) : _full(full) {};
1209 };
1210
1211 void GenCollectedHeap::gc_epilogue(bool full) {
1212 #if defined(COMPILER2) || INCLUDE_JVMCI
1213 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1214 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1215 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1216 #endif /* COMPILER2 || INCLUDE_JVMCI */
1217
1218 resize_all_tlabs();
1219
1220 GenGCEpilogueClosure blk(full);
1221 generation_iterate(&blk, false); // not old-to-young.
1222
1223 if (!CleanChunkPoolAsync) {
1224 Chunk::clean_chunk_pool();
1225 }
1226
1227 MetaspaceCounters::update_performance_counters();
1228 CompressedClassSpaceCounters::update_performance_counters();
1229
1230 always_do_update_barrier = UseConcMarkSweepGC;
1231 };
1232
1233 #ifndef PRODUCT
1234 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1235 private:
1236 public:
1237 void do_generation(Generation* gen) {
1238 gen->record_spaces_top();
1239 }
1240 };
1241
1242 void GenCollectedHeap::record_gen_tops_before_GC() {
1243 if (ZapUnusedHeapArea) {
1244 GenGCSaveTopsBeforeGCClosure blk;
1245 generation_iterate(&blk, false); // not old-to-young.
1246 }
1247 }
1248 #endif // not PRODUCT
1249
1250 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1251 public:
1252 void do_generation(Generation* gen) {
1253 gen->ensure_parsability();
1254 }
1255 };
1256
1257 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1258 CollectedHeap::ensure_parsability(retire_tlabs);
1259 GenEnsureParsabilityClosure ep_cl;
1260 generation_iterate(&ep_cl, false);
1261 }
1262
1263 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1264 oop obj,
1265 size_t obj_size) {
1266 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1267 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1268 HeapWord* result = NULL;
1269
1270 result = old_gen->expand_and_allocate(obj_size, false);
1271
1272 if (result != NULL) {
1273 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1274 }
1275 return oop(result);
1276 }
1277
1278 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1279 jlong _time; // in ms
1280 jlong _now; // in ms
1281
1282 public:
1283 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1284
1285 jlong time() { return _time; }
1286
1287 void do_generation(Generation* gen) {
1288 _time = MIN2(_time, gen->time_of_last_gc(_now));
1289 }
1290 };
1291
1292 jlong GenCollectedHeap::millis_since_last_gc() {
1293 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1294 // provided the underlying platform provides such a time source
1295 // (and it is bug free). So we still have to guard against getting
1296 // back a time later than 'now'.
1297 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1298 GenTimeOfLastGCClosure tolgc_cl(now);
1299 // iterate over generations getting the oldest
1300 // time that a generation was collected
1301 generation_iterate(&tolgc_cl, false);
1302
1303 jlong retVal = now - tolgc_cl.time();
1304 if (retVal < 0) {
1305 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1306 ". returning zero instead.", retVal);
1307 return 0;
1308 }
1309 return retVal;
1310 }
1311
1312 void GenCollectedHeap::stop() {
1313 #if INCLUDE_ALL_GCS
1314 if (UseConcMarkSweepGC) {
1315 ConcurrentMarkSweepThread::cmst()->stop();
1316 }
1317 #endif
1318 }
1319
1320 void GenCollectedHeap::safepoint_synchronize_begin() {
1321 #if INCLUDE_ALL_GCS
1322 if (UseConcMarkSweepGC) {
1323 ConcurrentMarkSweepThread::synchronize(false);
1324 }
1325 #endif
1326 }
1327
1328 void GenCollectedHeap::safepoint_synchronize_end() {
1329 #if INCLUDE_ALL_GCS
1330 if (UseConcMarkSweepGC) {
1331 ConcurrentMarkSweepThread::desynchronize(false);
1332 }
1333 #endif
1334 }