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