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