1 /*
2 * Copyright (c) 2000, 2017, 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/stringTable.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "gc/shared/collectedHeap.inline.hpp"
34 #include "gc/shared/collectorCounters.hpp"
35 #include "gc/shared/gcId.hpp"
36 #include "gc/shared/gcLocker.inline.hpp"
37 #include "gc/shared/gcTrace.hpp"
38 #include "gc/shared/gcTraceTime.inline.hpp"
39 #include "gc/shared/genCollectedHeap.hpp"
40 #include "gc/shared/genOopClosures.inline.hpp"
41 #include "gc/shared/generationSpec.hpp"
42 #include "gc/shared/space.hpp"
43 #include "gc/shared/strongRootsScope.hpp"
44 #include "gc/shared/vmGCOperations.hpp"
45 #include "gc/shared/workgroup.hpp"
46 #include "memory/filemap.hpp"
47 #include "memory/resourceArea.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fprofiler.hpp"
51 #include "runtime/handles.hpp"
52 #include "runtime/handles.inline.hpp"
53 #include "runtime/java.hpp"
54 #include "runtime/vmThread.hpp"
55 #include "services/management.hpp"
56 #include "services/memoryService.hpp"
57 #include "utilities/debug.hpp"
58 #include "utilities/formatBuffer.hpp"
59 #include "utilities/macros.hpp"
60 #include "utilities/stack.inline.hpp"
61 #include "utilities/vmError.hpp"
62 #if INCLUDE_ALL_GCS
63 #include "gc/cms/concurrentMarkSweepThread.hpp"
64 #include "gc/cms/vmCMSOperations.hpp"
65 #endif // INCLUDE_ALL_GCS
66
67 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
68
69 // The set of potentially parallel tasks in root scanning.
70 enum GCH_strong_roots_tasks {
71 GCH_PS_Universe_oops_do,
72 GCH_PS_JNIHandles_oops_do,
73 GCH_PS_ObjectSynchronizer_oops_do,
74 GCH_PS_FlatProfiler_oops_do,
75 GCH_PS_Management_oops_do,
76 GCH_PS_SystemDictionary_oops_do,
77 GCH_PS_ClassLoaderDataGraph_oops_do,
78 GCH_PS_jvmti_oops_do,
79 GCH_PS_CodeCache_oops_do,
80 GCH_PS_aot_oops_do,
81 GCH_PS_younger_gens,
82 // Leave this one last.
83 GCH_PS_NumElements
84 };
85
86 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
87 CollectedHeap(),
88 _rem_set(NULL),
89 _gen_policy(policy),
90 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
91 _full_collections_completed(0)
92 {
93 assert(policy != NULL, "Sanity check");
94 if (UseConcMarkSweepGC) {
95 _workers = new WorkGang("GC Thread", ParallelGCThreads,
96 /* are_GC_task_threads */true,
97 /* are_ConcurrentGC_threads */false);
98 _workers->initialize_workers();
99 } else {
100 // Serial GC does not use workers.
101 _workers = NULL;
102 }
103 }
104
105 jint GenCollectedHeap::initialize() {
106 CollectedHeap::pre_initialize();
107
108 // While there are no constraints in the GC code that HeapWordSize
109 // be any particular value, there are multiple other areas in the
110 // system which believe this to be true (e.g. oop->object_size in some
111 // cases incorrectly returns the size in wordSize units rather than
112 // HeapWordSize).
113 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
114
115 // Allocate space for the heap.
116
117 char* heap_address;
118 ReservedSpace heap_rs;
119
120 size_t heap_alignment = collector_policy()->heap_alignment();
121
122 heap_address = allocate(heap_alignment, &heap_rs);
123
124 if (!heap_rs.is_reserved()) {
125 vm_shutdown_during_initialization(
126 "Could not reserve enough space for object heap");
127 return JNI_ENOMEM;
128 }
129
130 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
131
132 _rem_set = collector_policy()->create_rem_set(reserved_region());
133 set_barrier_set(rem_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 ReferenceProcessorPhaseTimes pt(NULL, rp->num_q());
391 rp->enqueue_discovered_references(NULL, &pt);
392 pt.print_enqueue_phase();
393 } else {
394 rp->set_enqueuing_is_done(false);
395 }
396 rp->verify_no_references_recorded();
397 }
398
399 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
400
401 gen->stat_record()->accumulated_time.stop();
402
403 update_gc_stats(gen, full);
404
405 if (run_verification && VerifyAfterGC) {
406 HandleMark hm; // Discard invalid handles created during verification
407 Universe::verify("After GC");
408 }
409 }
410
411 void GenCollectedHeap::do_collection(bool full,
412 bool clear_all_soft_refs,
413 size_t size,
414 bool is_tlab,
415 GenerationType max_generation) {
416 ResourceMark rm;
417 DEBUG_ONLY(Thread* my_thread = Thread::current();)
418
419 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
420 assert(my_thread->is_VM_thread() ||
421 my_thread->is_ConcurrentGC_thread(),
422 "incorrect thread type capability");
423 assert(Heap_lock->is_locked(),
424 "the requesting thread should have the Heap_lock");
425 guarantee(!is_gc_active(), "collection is not reentrant");
426
427 if (GCLocker::check_active_before_gc()) {
428 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
429 }
430
431 GCIdMarkAndRestore gc_id_mark;
432
433 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
434 collector_policy()->should_clear_all_soft_refs();
435
436 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
437
438 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
439
440 print_heap_before_gc();
441
442 {
443 FlagSetting fl(_is_gc_active, true);
444
445 bool complete = full && (max_generation == OldGen);
446 bool old_collects_young = complete && !ScavengeBeforeFullGC;
447 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
448
449 FormatBuffer<> gc_string("%s", "Pause ");
450 if (do_young_collection) {
451 gc_string.append("Young");
452 } else {
453 gc_string.append("Full");
454 }
455
456 GCTraceCPUTime tcpu;
457 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true);
458
459 gc_prologue(complete);
460 increment_total_collections(complete);
461
462 size_t young_prev_used = _young_gen->used();
463 size_t old_prev_used = _old_gen->used();
464
465 bool run_verification = total_collections() >= VerifyGCStartAt;
466
467 bool prepared_for_verification = false;
468 bool collected_old = false;
469
470 if (do_young_collection) {
471 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
472 prepare_for_verify();
473 prepared_for_verification = true;
474 }
475
476 collect_generation(_young_gen,
477 full,
478 size,
479 is_tlab,
480 run_verification && VerifyGCLevel <= 0,
481 do_clear_all_soft_refs,
482 false);
483
484 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
485 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
486 // Allocation request was met by young GC.
487 size = 0;
488 }
489 }
490
491 bool must_restore_marks_for_biased_locking = false;
492
493 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) {
494 if (!complete) {
495 // The full_collections increment was missed above.
496 increment_total_full_collections();
497 }
498
499 if (!prepared_for_verification && run_verification &&
500 VerifyGCLevel <= 1 && VerifyBeforeGC) {
501 prepare_for_verify();
502 }
503
504 if (do_young_collection) {
505 // We did a young GC. Need a new GC id for the old GC.
506 GCIdMarkAndRestore gc_id_mark;
507 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
508 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
509 } else {
510 // No young GC done. Use the same GC id as was set up earlier in this method.
511 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
512 }
513
514 must_restore_marks_for_biased_locking = true;
515 collected_old = true;
516 }
517
518 // Update "complete" boolean wrt what actually transpired --
519 // for instance, a promotion failure could have led to
520 // a whole heap collection.
521 complete = complete || collected_old;
522
523 print_heap_change(young_prev_used, old_prev_used);
524 MetaspaceAux::print_metaspace_change(metadata_prev_used);
525
526 // Adjust generation sizes.
527 if (collected_old) {
528 _old_gen->compute_new_size();
529 }
530 _young_gen->compute_new_size();
531
532 if (complete) {
533 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
534 ClassLoaderDataGraph::purge();
535 MetaspaceAux::verify_metrics();
536 // Resize the metaspace capacity after full collections
537 MetaspaceGC::compute_new_size();
538 update_full_collections_completed();
539 }
540
541 // Track memory usage and detect low memory after GC finishes
542 MemoryService::track_memory_usage();
543
544 gc_epilogue(complete);
545
546 if (must_restore_marks_for_biased_locking) {
547 BiasedLocking::restore_marks();
548 }
549 }
550
551 print_heap_after_gc();
552
553 #ifdef TRACESPINNING
554 ParallelTaskTerminator::print_termination_counts();
555 #endif
556 }
557
558 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
559 return gen_policy()->satisfy_failed_allocation(size, is_tlab);
560 }
561
562 #ifdef ASSERT
563 class AssertNonScavengableClosure: public OopClosure {
564 public:
565 virtual void do_oop(oop* p) {
566 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
567 "Referent should not be scavengable."); }
568 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
569 };
570 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
571 #endif
572
573 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
574 ScanningOption so,
575 OopClosure* strong_roots,
576 OopClosure* weak_roots,
577 CLDClosure* strong_cld_closure,
578 CLDClosure* weak_cld_closure,
579 CodeBlobToOopClosure* code_roots) {
580 // General roots.
581 assert(Threads::thread_claim_parity() != 0, "must have called prologue code");
582 assert(code_roots != NULL, "code root closure should always be set");
583 // _n_termination for _process_strong_tasks should be set up stream
584 // in a method not running in a GC worker. Otherwise the GC worker
585 // could be trying to change the termination condition while the task
586 // is executing in another GC worker.
587
588 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
589 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
590 }
591
592 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
593 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
594
595 bool is_par = scope->n_threads() > 1;
596 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
597
598 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
599 Universe::oops_do(strong_roots);
600 }
601 // Global (strong) JNI handles
602 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
603 JNIHandles::oops_do(strong_roots);
604 }
605
606 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
607 ObjectSynchronizer::oops_do(strong_roots);
608 }
609 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
610 FlatProfiler::oops_do(strong_roots);
611 }
612 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
613 Management::oops_do(strong_roots);
614 }
615 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
616 JvmtiExport::oops_do(strong_roots);
617 }
618 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) {
619 AOTLoader::oops_do(strong_roots);
620 }
621
622 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
623 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
624 }
625
626 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
627 if (so & SO_ScavengeCodeCache) {
628 assert(code_roots != NULL, "must supply closure for code cache");
629
630 // We only visit parts of the CodeCache when scavenging.
631 CodeCache::scavenge_root_nmethods_do(code_roots);
632 }
633 if (so & SO_AllCodeCache) {
634 assert(code_roots != NULL, "must supply closure for code cache");
635
636 // CMSCollector uses this to do intermediate-strength collections.
637 // We scan the entire code cache, since CodeCache::do_unloading is not called.
638 CodeCache::blobs_do(code_roots);
639 }
640 // Verify that the code cache contents are not subject to
641 // movement by a scavenging collection.
642 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
643 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
644 }
645 }
646
647 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope,
648 OopClosure* root_closure) {
649 assert(root_closure != NULL, "Must be set");
650 // All threads execute the following. A specific chunk of buckets
651 // from the StringTable are the individual tasks.
652 if (scope->n_threads() > 1) {
653 StringTable::possibly_parallel_oops_do(root_closure);
654 } else {
655 StringTable::oops_do(root_closure);
656 }
657 }
658
659 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
660 OopsInGenClosure* root_closure,
661 OopsInGenClosure* old_gen_closure,
662 CLDClosure* cld_closure) {
663 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
664
665 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure,
666 cld_closure, cld_closure, &mark_code_closure);
667 process_string_table_roots(scope, root_closure);
668
669 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
670 root_closure->reset_generation();
671 }
672
673 // When collection is parallel, all threads get to cooperate to do
674 // old generation scanning.
675 old_gen_closure->set_generation(_old_gen);
676 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
677 old_gen_closure->reset_generation();
678
679 _process_strong_tasks->all_tasks_completed(scope->n_threads());
680 }
681
682 void GenCollectedHeap::cms_process_roots(StrongRootsScope* scope,
683 bool young_gen_as_roots,
684 ScanningOption so,
685 bool only_strong_roots,
686 OopsInGenClosure* root_closure,
687 CLDClosure* cld_closure) {
688 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations);
689 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
690 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
691
692 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
693 if (!only_strong_roots) {
694 process_string_table_roots(scope, root_closure);
695 }
696
697 if (young_gen_as_roots &&
698 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
699 root_closure->set_generation(_young_gen);
700 _young_gen->oop_iterate(root_closure);
701 root_closure->reset_generation();
702 }
703
704 _process_strong_tasks->all_tasks_completed(scope->n_threads());
705 }
706
707 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
708 bool is_adjust_phase,
709 ScanningOption so,
710 bool only_strong_roots,
711 OopsInGenClosure* root_closure,
712 CLDClosure* cld_closure) {
713 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
714 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
715 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
716
717 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
718 if (is_adjust_phase) {
719 // We never treat the string table as roots during marking
720 // for the full gc, so we only need to process it during
721 // the adjust phase.
722 process_string_table_roots(scope, root_closure);
723 }
724
725 _process_strong_tasks->all_tasks_completed(scope->n_threads());
726 }
727
728 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
729 JNIHandles::weak_oops_do(root_closure);
730 _young_gen->ref_processor()->weak_oops_do(root_closure);
731 _old_gen->ref_processor()->weak_oops_do(root_closure);
732 }
733
734 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
735 void GenCollectedHeap:: \
736 oop_since_save_marks_iterate(GenerationType gen, \
737 OopClosureType* cur, \
738 OopClosureType* older) { \
739 if (gen == YoungGen) { \
740 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
741 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
742 } else { \
743 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
744 } \
745 }
746
747 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
748
749 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
750
751 bool GenCollectedHeap::no_allocs_since_save_marks() {
752 return _young_gen->no_allocs_since_save_marks() &&
753 _old_gen->no_allocs_since_save_marks();
754 }
755
756 bool GenCollectedHeap::supports_inline_contig_alloc() const {
757 return _young_gen->supports_inline_contig_alloc();
758 }
759
760 HeapWord* volatile* GenCollectedHeap::top_addr() const {
761 return _young_gen->top_addr();
762 }
763
764 HeapWord** GenCollectedHeap::end_addr() const {
765 return _young_gen->end_addr();
766 }
767
768 // public collection interfaces
769
770 void GenCollectedHeap::collect(GCCause::Cause cause) {
771 if (should_do_concurrent_full_gc(cause)) {
772 #if INCLUDE_ALL_GCS
773 // Mostly concurrent full collection.
774 collect_mostly_concurrent(cause);
775 #else // INCLUDE_ALL_GCS
776 ShouldNotReachHere();
777 #endif // INCLUDE_ALL_GCS
778 } else if (cause == GCCause::_wb_young_gc) {
779 // Young collection for the WhiteBox API.
780 collect(cause, YoungGen);
781 } else {
782 #ifdef ASSERT
783 if (cause == GCCause::_scavenge_alot) {
784 // Young collection only.
785 collect(cause, YoungGen);
786 } else {
787 // Stop-the-world full collection.
788 collect(cause, OldGen);
789 }
790 #else
791 // Stop-the-world full collection.
792 collect(cause, OldGen);
793 #endif
794 }
795 }
796
797 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
798 // The caller doesn't have the Heap_lock
799 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
800 MutexLocker ml(Heap_lock);
801 collect_locked(cause, max_generation);
802 }
803
804 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
805 // The caller has the Heap_lock
806 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
807 collect_locked(cause, OldGen);
808 }
809
810 // this is the private collection interface
811 // The Heap_lock is expected to be held on entry.
812
813 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
814 // Read the GC count while holding the Heap_lock
815 unsigned int gc_count_before = total_collections();
816 unsigned int full_gc_count_before = total_full_collections();
817 {
818 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
819 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
820 cause, max_generation);
821 VMThread::execute(&op);
822 }
823 }
824
825 #if INCLUDE_ALL_GCS
826 bool GenCollectedHeap::create_cms_collector() {
827
828 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
829 "Unexpected generation kinds");
830 // Skip two header words in the block content verification
831 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
832 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type");
833 CMSCollector* collector =
834 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen,
835 _rem_set,
836 _gen_policy->as_concurrent_mark_sweep_policy());
837
838 if (collector == NULL || !collector->completed_initialization()) {
839 if (collector) {
840 delete collector; // Be nice in embedded situation
841 }
842 vm_shutdown_during_initialization("Could not create CMS collector");
843 return false;
844 }
845 return true; // success
846 }
847
848 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
849 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
850
851 MutexLocker ml(Heap_lock);
852 // Read the GC counts while holding the Heap_lock
853 unsigned int full_gc_count_before = total_full_collections();
854 unsigned int gc_count_before = total_collections();
855 {
856 MutexUnlocker mu(Heap_lock);
857 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
858 VMThread::execute(&op);
859 }
860 }
861 #endif // INCLUDE_ALL_GCS
862
863 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
864 do_full_collection(clear_all_soft_refs, OldGen);
865 }
866
867 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
868 GenerationType last_generation) {
869 GenerationType local_last_generation;
870 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
871 gc_cause() == GCCause::_gc_locker) {
872 local_last_generation = YoungGen;
873 } else {
874 local_last_generation = last_generation;
875 }
876
877 do_collection(true, // full
878 clear_all_soft_refs, // clear_all_soft_refs
879 0, // size
880 false, // is_tlab
881 local_last_generation); // last_generation
882 // Hack XXX FIX ME !!!
883 // A scavenge may not have been attempted, or may have
884 // been attempted and failed, because the old gen was too full
885 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker &&
886 incremental_collection_will_fail(false /* don't consult_young */)) {
887 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
888 // This time allow the old gen to be collected as well
889 do_collection(true, // full
890 clear_all_soft_refs, // clear_all_soft_refs
891 0, // size
892 false, // is_tlab
893 OldGen); // last_generation
894 }
895 }
896
897 bool GenCollectedHeap::is_in_young(oop p) {
898 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
899 assert(result == _young_gen->is_in_reserved(p),
900 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
901 return result;
902 }
903
904 // Returns "TRUE" iff "p" points into the committed areas of the heap.
905 bool GenCollectedHeap::is_in(const void* p) const {
906 return _young_gen->is_in(p) || _old_gen->is_in(p);
907 }
908
909 #ifdef ASSERT
910 // Don't implement this by using is_in_young(). This method is used
911 // in some cases to check that is_in_young() is correct.
912 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
913 assert(is_in_reserved(p) || p == NULL,
914 "Does not work if address is non-null and outside of the heap");
915 return p < _young_gen->reserved().end() && p != NULL;
916 }
917 #endif
918
919 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) {
920 NoHeaderExtendedOopClosure no_header_cl(cl);
921 oop_iterate(&no_header_cl);
922 }
923
924 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
925 _young_gen->oop_iterate(cl);
926 _old_gen->oop_iterate(cl);
927 }
928
929 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
930 _young_gen->object_iterate(cl);
931 _old_gen->object_iterate(cl);
932 }
933
934 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
935 _young_gen->safe_object_iterate(cl);
936 _old_gen->safe_object_iterate(cl);
937 }
938
939 Space* GenCollectedHeap::space_containing(const void* addr) const {
940 Space* res = _young_gen->space_containing(addr);
941 if (res != NULL) {
942 return res;
943 }
944 res = _old_gen->space_containing(addr);
945 assert(res != NULL, "Could not find containing space");
946 return res;
947 }
948
949 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
950 assert(is_in_reserved(addr), "block_start of address outside of heap");
951 if (_young_gen->is_in_reserved(addr)) {
952 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
953 return _young_gen->block_start(addr);
954 }
955
956 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
957 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
958 return _old_gen->block_start(addr);
959 }
960
961 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
962 assert(is_in_reserved(addr), "block_size of address outside of heap");
963 if (_young_gen->is_in_reserved(addr)) {
964 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
965 return _young_gen->block_size(addr);
966 }
967
968 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
969 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
970 return _old_gen->block_size(addr);
971 }
972
973 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
974 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
975 assert(block_start(addr) == addr, "addr must be a block start");
976 if (_young_gen->is_in_reserved(addr)) {
977 return _young_gen->block_is_obj(addr);
978 }
979
980 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
981 return _old_gen->block_is_obj(addr);
982 }
983
984 bool GenCollectedHeap::supports_tlab_allocation() const {
985 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
986 return _young_gen->supports_tlab_allocation();
987 }
988
989 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
990 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
991 if (_young_gen->supports_tlab_allocation()) {
992 return _young_gen->tlab_capacity();
993 }
994 return 0;
995 }
996
997 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
998 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
999 if (_young_gen->supports_tlab_allocation()) {
1000 return _young_gen->tlab_used();
1001 }
1002 return 0;
1003 }
1004
1005 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1006 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1007 if (_young_gen->supports_tlab_allocation()) {
1008 return _young_gen->unsafe_max_tlab_alloc();
1009 }
1010 return 0;
1011 }
1012
1013 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1014 bool gc_overhead_limit_was_exceeded;
1015 return gen_policy()->mem_allocate_work(size /* size */,
1016 true /* is_tlab */,
1017 &gc_overhead_limit_was_exceeded);
1018 }
1019
1020 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1021 // from the list headed by "*prev_ptr".
1022 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1023 bool first = true;
1024 size_t min_size = 0; // "first" makes this conceptually infinite.
1025 ScratchBlock **smallest_ptr, *smallest;
1026 ScratchBlock *cur = *prev_ptr;
1027 while (cur) {
1028 assert(*prev_ptr == cur, "just checking");
1029 if (first || cur->num_words < min_size) {
1030 smallest_ptr = prev_ptr;
1031 smallest = cur;
1032 min_size = smallest->num_words;
1033 first = false;
1034 }
1035 prev_ptr = &cur->next;
1036 cur = cur->next;
1037 }
1038 smallest = *smallest_ptr;
1039 *smallest_ptr = smallest->next;
1040 return smallest;
1041 }
1042
1043 // Sort the scratch block list headed by res into decreasing size order,
1044 // and set "res" to the result.
1045 static void sort_scratch_list(ScratchBlock*& list) {
1046 ScratchBlock* sorted = NULL;
1047 ScratchBlock* unsorted = list;
1048 while (unsorted) {
1049 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1050 smallest->next = sorted;
1051 sorted = smallest;
1052 }
1053 list = sorted;
1054 }
1055
1056 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1057 size_t max_alloc_words) {
1058 ScratchBlock* res = NULL;
1059 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1060 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1061 sort_scratch_list(res);
1062 return res;
1063 }
1064
1065 void GenCollectedHeap::release_scratch() {
1066 _young_gen->reset_scratch();
1067 _old_gen->reset_scratch();
1068 }
1069
1070 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1071 void do_generation(Generation* gen) {
1072 gen->prepare_for_verify();
1073 }
1074 };
1075
1076 void GenCollectedHeap::prepare_for_verify() {
1077 ensure_parsability(false); // no need to retire TLABs
1078 GenPrepareForVerifyClosure blk;
1079 generation_iterate(&blk, false);
1080 }
1081
1082 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1083 bool old_to_young) {
1084 if (old_to_young) {
1085 cl->do_generation(_old_gen);
1086 cl->do_generation(_young_gen);
1087 } else {
1088 cl->do_generation(_young_gen);
1089 cl->do_generation(_old_gen);
1090 }
1091 }
1092
1093 bool GenCollectedHeap::is_maximal_no_gc() const {
1094 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1095 }
1096
1097 void GenCollectedHeap::save_marks() {
1098 _young_gen->save_marks();
1099 _old_gen->save_marks();
1100 }
1101
1102 GenCollectedHeap* GenCollectedHeap::heap() {
1103 CollectedHeap* heap = Universe::heap();
1104 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1105 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap");
1106 return (GenCollectedHeap*)heap;
1107 }
1108
1109 void GenCollectedHeap::prepare_for_compaction() {
1110 // Start by compacting into same gen.
1111 CompactPoint cp(_old_gen);
1112 _old_gen->prepare_for_compaction(&cp);
1113 _young_gen->prepare_for_compaction(&cp);
1114 }
1115
1116 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1117 log_debug(gc, verify)("%s", _old_gen->name());
1118 _old_gen->verify();
1119
1120 log_debug(gc, verify)("%s", _old_gen->name());
1121 _young_gen->verify();
1122
1123 log_debug(gc, verify)("RemSet");
1124 rem_set()->verify();
1125 }
1126
1127 void GenCollectedHeap::print_on(outputStream* st) const {
1128 _young_gen->print_on(st);
1129 _old_gen->print_on(st);
1130 MetaspaceAux::print_on(st);
1131 }
1132
1133 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1134 if (workers() != NULL) {
1135 workers()->threads_do(tc);
1136 }
1137 #if INCLUDE_ALL_GCS
1138 if (UseConcMarkSweepGC) {
1139 ConcurrentMarkSweepThread::threads_do(tc);
1140 }
1141 #endif // INCLUDE_ALL_GCS
1142 }
1143
1144 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1145 #if INCLUDE_ALL_GCS
1146 if (UseConcMarkSweepGC) {
1147 workers()->print_worker_threads_on(st);
1148 ConcurrentMarkSweepThread::print_all_on(st);
1149 }
1150 #endif // INCLUDE_ALL_GCS
1151 }
1152
1153 void GenCollectedHeap::print_on_error(outputStream* st) const {
1154 this->CollectedHeap::print_on_error(st);
1155
1156 #if INCLUDE_ALL_GCS
1157 if (UseConcMarkSweepGC) {
1158 st->cr();
1159 CMSCollector::print_on_error(st);
1160 }
1161 #endif // INCLUDE_ALL_GCS
1162 }
1163
1164 void GenCollectedHeap::print_tracing_info() const {
1165 _young_gen->print_summary_info();
1166 _old_gen->print_summary_info();
1167 }
1168
1169 void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const {
1170 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1171 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K);
1172 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1173 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K);
1174 }
1175
1176 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1177 private:
1178 bool _full;
1179 public:
1180 void do_generation(Generation* gen) {
1181 gen->gc_prologue(_full);
1182 }
1183 GenGCPrologueClosure(bool full) : _full(full) {};
1184 };
1185
1186 void GenCollectedHeap::gc_prologue(bool full) {
1187 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1188
1189 always_do_update_barrier = false;
1190 // Fill TLAB's and such
1191 CollectedHeap::accumulate_statistics_all_tlabs();
1192 ensure_parsability(true); // retire TLABs
1193
1194 // Walk generations
1195 GenGCPrologueClosure blk(full);
1196 generation_iterate(&blk, false); // not old-to-young.
1197 };
1198
1199 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1200 private:
1201 bool _full;
1202 public:
1203 void do_generation(Generation* gen) {
1204 gen->gc_epilogue(_full);
1205 }
1206 GenGCEpilogueClosure(bool full) : _full(full) {};
1207 };
1208
1209 void GenCollectedHeap::gc_epilogue(bool full) {
1210 #if defined(COMPILER2) || INCLUDE_JVMCI
1211 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1212 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1213 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1214 #endif /* COMPILER2 || INCLUDE_JVMCI */
1215
1216 resize_all_tlabs();
1217
1218 GenGCEpilogueClosure blk(full);
1219 generation_iterate(&blk, false); // not old-to-young.
1220
1221 if (!CleanChunkPoolAsync) {
1222 Chunk::clean_chunk_pool();
1223 }
1224
1225 MetaspaceCounters::update_performance_counters();
1226 CompressedClassSpaceCounters::update_performance_counters();
1227
1228 always_do_update_barrier = UseConcMarkSweepGC;
1229 };
1230
1231 #ifndef PRODUCT
1232 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1233 private:
1234 public:
1235 void do_generation(Generation* gen) {
1236 gen->record_spaces_top();
1237 }
1238 };
1239
1240 void GenCollectedHeap::record_gen_tops_before_GC() {
1241 if (ZapUnusedHeapArea) {
1242 GenGCSaveTopsBeforeGCClosure blk;
1243 generation_iterate(&blk, false); // not old-to-young.
1244 }
1245 }
1246 #endif // not PRODUCT
1247
1248 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1249 public:
1250 void do_generation(Generation* gen) {
1251 gen->ensure_parsability();
1252 }
1253 };
1254
1255 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1256 CollectedHeap::ensure_parsability(retire_tlabs);
1257 GenEnsureParsabilityClosure ep_cl;
1258 generation_iterate(&ep_cl, false);
1259 }
1260
1261 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1262 oop obj,
1263 size_t obj_size) {
1264 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1265 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1266 HeapWord* result = NULL;
1267
1268 result = old_gen->expand_and_allocate(obj_size, false);
1269
1270 if (result != NULL) {
1271 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1272 }
1273 return oop(result);
1274 }
1275
1276 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1277 jlong _time; // in ms
1278 jlong _now; // in ms
1279
1280 public:
1281 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1282
1283 jlong time() { return _time; }
1284
1285 void do_generation(Generation* gen) {
1286 _time = MIN2(_time, gen->time_of_last_gc(_now));
1287 }
1288 };
1289
1290 jlong GenCollectedHeap::millis_since_last_gc() {
1291 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1292 // provided the underlying platform provides such a time source
1293 // (and it is bug free). So we still have to guard against getting
1294 // back a time later than 'now'.
1295 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1296 GenTimeOfLastGCClosure tolgc_cl(now);
1297 // iterate over generations getting the oldest
1298 // time that a generation was collected
1299 generation_iterate(&tolgc_cl, false);
1300
1301 jlong retVal = now - tolgc_cl.time();
1302 if (retVal < 0) {
1303 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1304 ". returning zero instead.", retVal);
1305 return 0;
1306 }
1307 return retVal;
1308 }
1309
1310 void GenCollectedHeap::stop() {
1311 #if INCLUDE_ALL_GCS
1312 if (UseConcMarkSweepGC) {
1313 ConcurrentMarkSweepThread::cmst()->stop();
1314 }
1315 #endif
1316 }