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