1 /*
2 * Copyright (c) 2000, 2015, 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 "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/codeCache.hpp"
30 #include "code/icBuffer.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "gc/shared/collectorCounters.hpp"
33 #include "gc/shared/gcLocker.inline.hpp"
34 #include "gc/shared/gcTrace.hpp"
35 #include "gc/shared/gcTraceTime.hpp"
36 #include "gc/shared/genCollectedHeap.hpp"
37 #include "gc/shared/genOopClosures.inline.hpp"
38 #include "gc/shared/generationSpec.hpp"
39 #include "gc/shared/space.hpp"
40 #include "gc/shared/strongRootsScope.hpp"
41 #include "gc/shared/vmGCOperations.hpp"
42 #include "gc/shared/workgroup.hpp"
43 #include "memory/filemap.hpp"
44 #include "memory/resourceArea.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "runtime/biasedLocking.hpp"
47 #include "runtime/fprofiler.hpp"
48 #include "runtime/handles.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/java.hpp"
51 #include "runtime/vmThread.hpp"
52 #include "services/management.hpp"
53 #include "services/memoryService.hpp"
54 #include "utilities/macros.hpp"
55 #include "utilities/stack.inline.hpp"
56 #include "utilities/vmError.hpp"
57 #if INCLUDE_ALL_GCS
58 #include "gc/cms/concurrentMarkSweepThread.hpp"
59 #include "gc/cms/vmCMSOperations.hpp"
60 #endif // INCLUDE_ALL_GCS
61
62 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
63
64 // The set of potentially parallel tasks in root scanning.
65 enum GCH_strong_roots_tasks {
66 GCH_PS_Universe_oops_do,
67 GCH_PS_JNIHandles_oops_do,
68 GCH_PS_ObjectSynchronizer_oops_do,
69 GCH_PS_FlatProfiler_oops_do,
70 GCH_PS_Management_oops_do,
71 GCH_PS_SystemDictionary_oops_do,
72 GCH_PS_ClassLoaderDataGraph_oops_do,
73 GCH_PS_jvmti_oops_do,
74 GCH_PS_CodeCache_oops_do,
75 GCH_PS_younger_gens,
76 // Leave this one last.
77 GCH_PS_NumElements
78 };
79
80 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
81 CollectedHeap(),
82 _rem_set(NULL),
83 _gen_policy(policy),
84 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
85 _full_collections_completed(0)
86 {
87 assert(policy != NULL, "Sanity check");
88 if (UseConcMarkSweepGC) {
89 _workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads,
90 /* are_GC_task_threads */true,
91 /* are_ConcurrentGC_threads */false);
92 _workers->initialize_workers();
93 } else {
94 // Serial GC does not use workers.
95 _workers = NULL;
96 }
97 }
98
99 jint GenCollectedHeap::initialize() {
100 CollectedHeap::pre_initialize();
101
102 // While there are no constraints in the GC code that HeapWordSize
103 // be any particular value, there are multiple other areas in the
104 // system which believe this to be true (e.g. oop->object_size in some
105 // cases incorrectly returns the size in wordSize units rather than
106 // HeapWordSize).
107 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
108
109 // Allocate space for the heap.
110
111 char* heap_address;
112 ReservedSpace heap_rs;
113
114 size_t heap_alignment = collector_policy()->heap_alignment();
115
116 heap_address = allocate(heap_alignment, &heap_rs);
117
118 if (!heap_rs.is_reserved()) {
119 vm_shutdown_during_initialization(
120 "Could not reserve enough space for object heap");
121 return JNI_ENOMEM;
122 }
123
124 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
125
126 _rem_set = collector_policy()->create_rem_set(reserved_region());
127 set_barrier_set(rem_set()->bs());
128
129 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false);
130 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, 0, rem_set());
131 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size());
132
133 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false);
134 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, 1, rem_set());
135 clear_incremental_collection_failed();
136
137 #if INCLUDE_ALL_GCS
138 // If we are running CMS, create the collector responsible
139 // for collecting the CMS generations.
140 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
141 bool success = create_cms_collector();
142 if (!success) return JNI_ENOMEM;
143 }
144 #endif // INCLUDE_ALL_GCS
145
146 return JNI_OK;
147 }
148
149 char* GenCollectedHeap::allocate(size_t alignment,
150 ReservedSpace* heap_rs){
151 // Now figure out the total size.
152 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
153 assert(alignment % pageSize == 0, "Must be");
154
155 GenerationSpec* young_spec = gen_policy()->young_gen_spec();
156 GenerationSpec* old_spec = gen_policy()->old_gen_spec();
157
158 // Check for overflow.
159 size_t total_reserved = young_spec->max_size() + old_spec->max_size();
160 if (total_reserved < young_spec->max_size()) {
161 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
162 "the maximum representable size");
163 }
164 assert(total_reserved % alignment == 0,
165 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
166 SIZE_FORMAT, total_reserved, alignment));
167
168 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
169 return heap_rs->base();
170 }
171
172 void GenCollectedHeap::post_initialize() {
173 CollectedHeap::post_initialize();
174 ref_processing_init();
175 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
176 guarantee(policy->is_generation_policy(), "Illegal policy type");
177 assert((_young_gen->kind() == Generation::DefNew) ||
178 (_young_gen->kind() == Generation::ParNew),
179 "Wrong youngest generation type");
180 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
181
182 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep ||
183 _old_gen->kind() == Generation::MarkSweepCompact,
184 "Wrong generation kind");
185
186 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
187 _old_gen->capacity(),
188 def_new_gen->from()->capacity());
189 policy->initialize_gc_policy_counters();
190 }
191
192 void GenCollectedHeap::ref_processing_init() {
193 _young_gen->ref_processor_init();
194 _old_gen->ref_processor_init();
195 }
196
197 size_t GenCollectedHeap::capacity() const {
198 return _young_gen->capacity() + _old_gen->capacity();
199 }
200
201 size_t GenCollectedHeap::used() const {
202 return _young_gen->used() + _old_gen->used();
203 }
204
205 // Save the "used_region" for generations level and lower.
206 void GenCollectedHeap::save_used_regions(int level) {
207 assert(level == 0 || level == 1, "Illegal level parameter");
208 if (level == 1) {
209 _old_gen->save_used_region();
210 }
211 _young_gen->save_used_region();
212 }
213
214 size_t GenCollectedHeap::max_capacity() const {
215 return _young_gen->max_capacity() + _old_gen->max_capacity();
216 }
217
218 // Update the _full_collections_completed counter
219 // at the end of a stop-world full GC.
220 unsigned int GenCollectedHeap::update_full_collections_completed() {
221 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
222 assert(_full_collections_completed <= _total_full_collections,
223 "Can't complete more collections than were started");
224 _full_collections_completed = _total_full_collections;
225 ml.notify_all();
226 return _full_collections_completed;
227 }
228
229 // Update the _full_collections_completed counter, as appropriate,
230 // at the end of a concurrent GC cycle. Note the conditional update
231 // below to allow this method to be called by a concurrent collector
232 // without synchronizing in any manner with the VM thread (which
233 // may already have initiated a STW full collection "concurrently").
234 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
235 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
236 assert((_full_collections_completed <= _total_full_collections) &&
237 (count <= _total_full_collections),
238 "Can't complete more collections than were started");
239 if (count > _full_collections_completed) {
240 _full_collections_completed = count;
241 ml.notify_all();
242 }
243 return _full_collections_completed;
244 }
245
246
247 #ifndef PRODUCT
248 // Override of memory state checking method in CollectedHeap:
249 // Some collectors (CMS for example) can't have badHeapWordVal written
250 // in the first two words of an object. (For instance , in the case of
251 // CMS these words hold state used to synchronize between certain
252 // (concurrent) GC steps and direct allocating mutators.)
253 // The skip_header_HeapWords() method below, allows us to skip
254 // over the requisite number of HeapWord's. Note that (for
255 // generational collectors) this means that those many words are
256 // skipped in each object, irrespective of the generation in which
257 // that object lives. The resultant loss of precision seems to be
258 // harmless and the pain of avoiding that imprecision appears somewhat
259 // higher than we are prepared to pay for such rudimentary debugging
260 // support.
261 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
262 size_t size) {
263 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
264 // We are asked to check a size in HeapWords,
265 // but the memory is mangled in juint words.
266 juint* start = (juint*) (addr + skip_header_HeapWords());
267 juint* end = (juint*) (addr + size);
268 for (juint* slot = start; slot < end; slot += 1) {
269 assert(*slot == badHeapWordVal,
270 "Found non badHeapWordValue in pre-allocation check");
271 }
272 }
273 }
274 #endif
275
276 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
277 bool is_tlab,
278 bool first_only) {
279 HeapWord* res = NULL;
280
281 if (_young_gen->should_allocate(size, is_tlab)) {
282 res = _young_gen->allocate(size, is_tlab);
283 if (res != NULL || first_only) {
284 return res;
285 }
286 }
287
288 if (_old_gen->should_allocate(size, is_tlab)) {
289 res = _old_gen->allocate(size, is_tlab);
290 }
291
292 return res;
293 }
294
295 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
296 bool* gc_overhead_limit_was_exceeded) {
297 return collector_policy()->mem_allocate_work(size,
298 false /* is_tlab */,
299 gc_overhead_limit_was_exceeded);
300 }
301
302 bool GenCollectedHeap::must_clear_all_soft_refs() {
303 return _gc_cause == GCCause::_last_ditch_collection;
304 }
305
306 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
307 return UseConcMarkSweepGC &&
308 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
309 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
310 }
311
312 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
313 bool is_tlab, bool run_verification, bool clear_soft_refs,
314 bool restore_marks_for_biased_locking) {
315 // Timer for individual generations. Last argument is false: no CR
316 // FIXME: We should try to start the timing earlier to cover more of the GC pause
317 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
318 // so we can assume here that the next GC id is what we want.
319 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek());
320 TraceCollectorStats tcs(gen->counters());
321 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
322
323 size_t prev_used = gen->used();
324 gen->stat_record()->invocations++;
325 gen->stat_record()->accumulated_time.start();
326
327 // Must be done anew before each collection because
328 // a previous collection will do mangling and will
329 // change top of some spaces.
330 record_gen_tops_before_GC();
331
332 if (PrintGC && Verbose) {
333 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
334 gen->level(),
335 gen->stat_record()->invocations,
336 size * HeapWordSize);
337 }
338
339 if (run_verification && VerifyBeforeGC) {
340 HandleMark hm; // Discard invalid handles created during verification
341 Universe::verify(" VerifyBeforeGC:");
342 }
343 COMPILER2_PRESENT(DerivedPointerTable::clear());
344
345 if (restore_marks_for_biased_locking) {
346 // We perform this mark word preservation work lazily
347 // because it's only at this point that we know whether we
348 // absolutely have to do it; we want to avoid doing it for
349 // scavenge-only collections where it's unnecessary
350 BiasedLocking::preserve_marks();
351 }
352
353 // Do collection work
354 {
355 // Note on ref discovery: For what appear to be historical reasons,
356 // GCH enables and disabled (by enqueing) refs discovery.
357 // In the future this should be moved into the generation's
358 // collect method so that ref discovery and enqueueing concerns
359 // are local to a generation. The collect method could return
360 // an appropriate indication in the case that notification on
361 // the ref lock was needed. This will make the treatment of
362 // weak refs more uniform (and indeed remove such concerns
363 // from GCH). XXX
364
365 HandleMark hm; // Discard invalid handles created during gc
366 save_marks(); // save marks for all gens
367 // We want to discover references, but not process them yet.
368 // This mode is disabled in process_discovered_references if the
369 // generation does some collection work, or in
370 // enqueue_discovered_references if the generation returns
371 // without doing any work.
372 ReferenceProcessor* rp = gen->ref_processor();
373 // If the discovery of ("weak") refs in this generation is
374 // atomic wrt other collectors in this configuration, we
375 // are guaranteed to have empty discovered ref lists.
376 if (rp->discovery_is_atomic()) {
377 rp->enable_discovery();
378 rp->setup_policy(clear_soft_refs);
379 } else {
380 // collect() below will enable discovery as appropriate
381 }
382 gen->collect(full, clear_soft_refs, size, is_tlab);
383 if (!rp->enqueuing_is_done()) {
384 rp->enqueue_discovered_references();
385 } else {
386 rp->set_enqueuing_is_done(false);
387 }
388 rp->verify_no_references_recorded();
389 }
390
391 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
392
393 gen->stat_record()->accumulated_time.stop();
394
395 update_gc_stats(gen->level(), full);
396
397 if (run_verification && VerifyAfterGC) {
398 HandleMark hm; // Discard invalid handles created during verification
399 Universe::verify(" VerifyAfterGC:");
400 }
401
402 if (PrintGCDetails) {
403 gclog_or_tty->print(":");
404 gen->print_heap_change(prev_used);
405 }
406 }
407
408 void GenCollectedHeap::do_collection(bool full,
409 bool clear_all_soft_refs,
410 size_t size,
411 bool is_tlab,
412 int max_level) {
413 ResourceMark rm;
414 DEBUG_ONLY(Thread* my_thread = Thread::current();)
415
416 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
417 assert(my_thread->is_VM_thread() ||
418 my_thread->is_ConcurrentGC_thread(),
419 "incorrect thread type capability");
420 assert(Heap_lock->is_locked(),
421 "the requesting thread should have the Heap_lock");
422 guarantee(!is_gc_active(), "collection is not reentrant");
423
424 if (GC_locker::check_active_before_gc()) {
425 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
426 }
427
428 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
429 collector_policy()->should_clear_all_soft_refs();
430
431 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
432
433 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
434
435 print_heap_before_gc();
436
437 {
438 FlagSetting fl(_is_gc_active, true);
439
440 bool complete = full && (max_level == 1 /* old */);
441 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
442 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
443 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
444 // so we can assume here that the next GC id is what we want.
445 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
446
447 gc_prologue(complete);
448 increment_total_collections(complete);
449
450 size_t gch_prev_used = used();
451 bool run_verification = total_collections() >= VerifyGCStartAt;
452
453 bool prepared_for_verification = false;
454 int max_level_collected = 0;
455 bool old_collects_young = (max_level == 1) &&
456 full &&
457 _old_gen->full_collects_younger_generations();
458 if (!old_collects_young &&
459 _young_gen->should_collect(full, size, is_tlab)) {
460 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
461 prepare_for_verify();
462 prepared_for_verification = true;
463 }
464
465 assert(!_young_gen->performs_in_place_marking(), "No young generation do in place marking");
466 collect_generation(_young_gen,
467 full,
468 size,
469 is_tlab,
470 run_verification && VerifyGCLevel <= 0,
471 do_clear_all_soft_refs,
472 false);
473
474 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
475 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
476 // Allocation request was met by young GC.
477 size = 0;
478 }
479 }
480
481 bool must_restore_marks_for_biased_locking = false;
482
483 if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) {
484 if (!complete) {
485 // The full_collections increment was missed above.
486 increment_total_full_collections();
487 }
488
489 pre_full_gc_dump(NULL); // do any pre full gc dumps
490
491 if (!prepared_for_verification && run_verification &&
492 VerifyGCLevel <= 1 && VerifyBeforeGC) {
493 prepare_for_verify();
494 }
495
496 assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking");
497 collect_generation(_old_gen,
498 full,
499 size,
500 is_tlab,
501 run_verification && VerifyGCLevel <= 1,
502 do_clear_all_soft_refs,
503 true);
504
505 must_restore_marks_for_biased_locking = true;
506 max_level_collected = 1;
507 }
508
509 // Update "complete" boolean wrt what actually transpired --
510 // for instance, a promotion failure could have led to
511 // a whole heap collection.
512 complete = complete || (max_level_collected == 1 /* old */);
513
514 if (complete) { // We did a "major" collection
515 // FIXME: See comment at pre_full_gc_dump call
516 post_full_gc_dump(NULL); // do any post full gc dumps
517 }
518
519 if (PrintGCDetails) {
520 print_heap_change(gch_prev_used);
521
522 // Print metaspace info for full GC with PrintGCDetails flag.
523 if (complete) {
524 MetaspaceAux::print_metaspace_change(metadata_prev_used);
525 }
526 }
527
528 // Adjust generation sizes.
529 if (max_level_collected == 1 /* old */) {
530 _old_gen->compute_new_size();
531 }
532 _young_gen->compute_new_size();
533
534 if (complete) {
535 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
536 ClassLoaderDataGraph::purge();
537 MetaspaceAux::verify_metrics();
538 // Resize the metaspace capacity after full collections
539 MetaspaceGC::compute_new_size();
540 update_full_collections_completed();
541 }
542
543 // Track memory usage and detect low memory after GC finishes
544 MemoryService::track_memory_usage();
545
546 gc_epilogue(complete);
547
548 if (must_restore_marks_for_biased_locking) {
549 BiasedLocking::restore_marks();
550 }
551 }
552
553 print_heap_after_gc();
554
555 #ifdef TRACESPINNING
556 ParallelTaskTerminator::print_termination_counts();
557 #endif
558 }
559
560 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
561 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
562 }
563
564 #ifdef ASSERT
565 class AssertNonScavengableClosure: public OopClosure {
566 public:
567 virtual void do_oop(oop* p) {
568 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
569 "Referent should not be scavengable."); }
570 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
571 };
572 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
573 #endif
574
575 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
576 ScanningOption so,
577 OopClosure* strong_roots,
578 OopClosure* weak_roots,
579 CLDClosure* strong_cld_closure,
580 CLDClosure* weak_cld_closure,
581 CodeBlobClosure* code_roots) {
582 // General roots.
583 assert(Threads::thread_claim_parity() != 0, "must have called prologue code");
584 assert(code_roots != NULL, "code root closure should always be set");
585 // _n_termination for _process_strong_tasks should be set up stream
586 // in a method not running in a GC worker. Otherwise the GC worker
587 // could be trying to change the termination condition while the task
588 // is executing in another GC worker.
589
590 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
591 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
592 }
593
594 // Some CLDs contained in the thread frames should be considered strong.
595 // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
596 CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
597 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
598 CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
599
600 bool is_par = scope->n_threads() > 1;
601 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_clds_p, roots_from_code_p);
602
603 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
604 Universe::oops_do(strong_roots);
605 }
606 // Global (strong) JNI handles
607 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
608 JNIHandles::oops_do(strong_roots);
609 }
610
611 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
612 ObjectSynchronizer::oops_do(strong_roots);
613 }
614 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
615 FlatProfiler::oops_do(strong_roots);
616 }
617 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
618 Management::oops_do(strong_roots);
619 }
620 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
621 JvmtiExport::oops_do(strong_roots);
622 }
623
624 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
625 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
626 }
627
628 // All threads execute the following. A specific chunk of buckets
629 // from the StringTable are the individual tasks.
630 if (weak_roots != NULL) {
631 if (is_par) {
632 StringTable::possibly_parallel_oops_do(weak_roots);
633 } else {
634 StringTable::oops_do(weak_roots);
635 }
636 }
637
638 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
639 if (so & SO_ScavengeCodeCache) {
640 assert(code_roots != NULL, "must supply closure for code cache");
641
642 // We only visit parts of the CodeCache when scavenging.
643 CodeCache::scavenge_root_nmethods_do(code_roots);
644 }
645 if (so & SO_AllCodeCache) {
646 assert(code_roots != NULL, "must supply closure for code cache");
647
648 // CMSCollector uses this to do intermediate-strength collections.
649 // We scan the entire code cache, since CodeCache::do_unloading is not called.
650 CodeCache::blobs_do(code_roots);
651 }
652 // Verify that the code cache contents are not subject to
653 // movement by a scavenging collection.
654 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
655 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
656 }
657
658 }
659
660 void GenCollectedHeap::gen_process_roots(StrongRootsScope* scope,
661 int level,
662 bool younger_gens_as_roots,
663 ScanningOption so,
664 bool only_strong_roots,
665 OopsInGenClosure* not_older_gens,
666 OopsInGenClosure* older_gens,
667 CLDClosure* cld_closure) {
668 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
669
670 bool is_moving_collection = false;
671 if (level == 0 || is_adjust_phase) {
672 // young collections are always moving
673 is_moving_collection = true;
674 }
675
676 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
677 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : not_older_gens;
678 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
679
680 process_roots(scope, so,
681 not_older_gens, weak_roots,
682 cld_closure, weak_cld_closure,
683 &mark_code_closure);
684
685 if (younger_gens_as_roots) {
686 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
687 if (level == 1) {
688 not_older_gens->set_generation(_young_gen);
689 _young_gen->oop_iterate(not_older_gens);
690 }
691 not_older_gens->reset_generation();
692 }
693 }
694 // When collection is parallel, all threads get to cooperate to do
695 // older-gen scanning.
696 if (level == 0) {
697 older_gens->set_generation(_old_gen);
698 rem_set()->younger_refs_iterate(_old_gen, older_gens, scope->n_threads());
699 older_gens->reset_generation();
700 }
701
702 _process_strong_tasks->all_tasks_completed(scope->n_threads());
703 }
704
705
706 class AlwaysTrueClosure: public BoolObjectClosure {
707 public:
708 bool do_object_b(oop p) { return true; }
709 };
710 static AlwaysTrueClosure always_true;
711
712 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
713 JNIHandles::weak_oops_do(&always_true, root_closure);
714 _young_gen->ref_processor()->weak_oops_do(root_closure);
715 _old_gen->ref_processor()->weak_oops_do(root_closure);
716 }
717
718 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
719 void GenCollectedHeap:: \
720 oop_since_save_marks_iterate(int level, \
721 OopClosureType* cur, \
722 OopClosureType* older) { \
723 if (level == 0) { \
724 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
725 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
726 } else { \
727 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
728 } \
729 }
730
731 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
732
733 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
734
735 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
736 if (level == 0 && !_young_gen->no_allocs_since_save_marks()) {
737 return false;
738 }
739 return _old_gen->no_allocs_since_save_marks();
740 }
741
742 bool GenCollectedHeap::supports_inline_contig_alloc() const {
743 return _young_gen->supports_inline_contig_alloc();
744 }
745
746 HeapWord** GenCollectedHeap::top_addr() const {
747 return _young_gen->top_addr();
748 }
749
750 HeapWord** GenCollectedHeap::end_addr() const {
751 return _young_gen->end_addr();
752 }
753
754 // public collection interfaces
755
756 void GenCollectedHeap::collect(GCCause::Cause cause) {
757 if (should_do_concurrent_full_gc(cause)) {
758 #if INCLUDE_ALL_GCS
759 // mostly concurrent full collection
760 collect_mostly_concurrent(cause);
761 #else // INCLUDE_ALL_GCS
762 ShouldNotReachHere();
763 #endif // INCLUDE_ALL_GCS
764 } else if (cause == GCCause::_wb_young_gc) {
765 // minor collection for WhiteBox API
766 collect(cause, 0 /* young */);
767 } else {
768 #ifdef ASSERT
769 if (cause == GCCause::_scavenge_alot) {
770 // minor collection only
771 collect(cause, 0 /* young */);
772 } else {
773 // Stop-the-world full collection
774 collect(cause, 1 /* old */);
775 }
776 #else
777 // Stop-the-world full collection
778 collect(cause, 1 /* old */);
779 #endif
780 }
781 }
782
783 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
784 // The caller doesn't have the Heap_lock
785 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
786 MutexLocker ml(Heap_lock);
787 collect_locked(cause, max_level);
788 }
789
790 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
791 // The caller has the Heap_lock
792 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
793 collect_locked(cause, 1 /* old */);
794 }
795
796 // this is the private collection interface
797 // The Heap_lock is expected to be held on entry.
798
799 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
800 // Read the GC count while holding the Heap_lock
801 unsigned int gc_count_before = total_collections();
802 unsigned int full_gc_count_before = total_full_collections();
803 {
804 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
805 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
806 cause, max_level);
807 VMThread::execute(&op);
808 }
809 }
810
811 #if INCLUDE_ALL_GCS
812 bool GenCollectedHeap::create_cms_collector() {
813
814 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
815 "Unexpected generation kinds");
816 // Skip two header words in the block content verification
817 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
818 CMSCollector* collector = new CMSCollector(
819 (ConcurrentMarkSweepGeneration*)_old_gen,
820 _rem_set->as_CardTableRS(),
821 (ConcurrentMarkSweepPolicy*) collector_policy());
822
823 if (collector == NULL || !collector->completed_initialization()) {
824 if (collector) {
825 delete collector; // Be nice in embedded situation
826 }
827 vm_shutdown_during_initialization("Could not create CMS collector");
828 return false;
829 }
830 return true; // success
831 }
832
833 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
834 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
835
836 MutexLocker ml(Heap_lock);
837 // Read the GC counts while holding the Heap_lock
838 unsigned int full_gc_count_before = total_full_collections();
839 unsigned int gc_count_before = total_collections();
840 {
841 MutexUnlocker mu(Heap_lock);
842 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
843 VMThread::execute(&op);
844 }
845 }
846 #endif // INCLUDE_ALL_GCS
847
848 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
849 do_full_collection(clear_all_soft_refs, 1 /* old */);
850 }
851
852 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
853 int max_level) {
854 int local_max_level;
855 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
856 gc_cause() == GCCause::_gc_locker) {
857 local_max_level = 0;
858 } else {
859 local_max_level = max_level;
860 }
861
862 do_collection(true /* full */,
863 clear_all_soft_refs /* clear_all_soft_refs */,
864 0 /* size */,
865 false /* is_tlab */,
866 local_max_level /* max_level */);
867 // Hack XXX FIX ME !!!
868 // A scavenge may not have been attempted, or may have
869 // been attempted and failed, because the old gen was too full
870 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
871 incremental_collection_will_fail(false /* don't consult_young */)) {
872 if (PrintGCDetails) {
873 gclog_or_tty->print_cr("GC locker: Trying a full collection "
874 "because scavenge failed");
875 }
876 // This time allow the old gen to be collected as well
877 do_collection(true /* full */,
878 clear_all_soft_refs /* clear_all_soft_refs */,
879 0 /* size */,
880 false /* is_tlab */,
881 1 /* old */ /* max_level */);
882 }
883 }
884
885 bool GenCollectedHeap::is_in_young(oop p) {
886 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
887 assert(result == _young_gen->is_in_reserved(p),
888 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
889 return result;
890 }
891
892 // Returns "TRUE" iff "p" points into the committed areas of the heap.
893 bool GenCollectedHeap::is_in(const void* p) const {
894 return _young_gen->is_in(p) || _old_gen->is_in(p);
895 }
896
897 #ifdef ASSERT
898 // Don't implement this by using is_in_young(). This method is used
899 // in some cases to check that is_in_young() is correct.
900 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
901 assert(is_in_reserved(p) || p == NULL,
902 "Does not work if address is non-null and outside of the heap");
903 return p < _young_gen->reserved().end() && p != NULL;
904 }
905 #endif
906
907 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) {
908 NoHeaderExtendedOopClosure no_header_cl(cl);
909 oop_iterate(&no_header_cl);
910 }
911
912 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
913 _young_gen->oop_iterate(cl);
914 _old_gen->oop_iterate(cl);
915 }
916
917 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
918 _young_gen->object_iterate(cl);
919 _old_gen->object_iterate(cl);
920 }
921
922 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
923 _young_gen->safe_object_iterate(cl);
924 _old_gen->safe_object_iterate(cl);
925 }
926
927 Space* GenCollectedHeap::space_containing(const void* addr) const {
928 Space* res = _young_gen->space_containing(addr);
929 if (res != NULL) {
930 return res;
931 }
932 res = _old_gen->space_containing(addr);
933 assert(res != NULL, "Could not find containing space");
934 return res;
935 }
936
937 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
938 assert(is_in_reserved(addr), "block_start of address outside of heap");
939 if (_young_gen->is_in_reserved(addr)) {
940 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
941 return _young_gen->block_start(addr);
942 }
943
944 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
945 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
946 return _old_gen->block_start(addr);
947 }
948
949 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
950 assert(is_in_reserved(addr), "block_size of address outside of heap");
951 if (_young_gen->is_in_reserved(addr)) {
952 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
953 return _young_gen->block_size(addr);
954 }
955
956 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
957 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
958 return _old_gen->block_size(addr);
959 }
960
961 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
962 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
963 assert(block_start(addr) == addr, "addr must be a block start");
964 if (_young_gen->is_in_reserved(addr)) {
965 return _young_gen->block_is_obj(addr);
966 }
967
968 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
969 return _old_gen->block_is_obj(addr);
970 }
971
972 bool GenCollectedHeap::supports_tlab_allocation() const {
973 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
974 return _young_gen->supports_tlab_allocation();
975 }
976
977 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
978 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
979 if (_young_gen->supports_tlab_allocation()) {
980 return _young_gen->tlab_capacity();
981 }
982 return 0;
983 }
984
985 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
986 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
987 if (_young_gen->supports_tlab_allocation()) {
988 return _young_gen->tlab_used();
989 }
990 return 0;
991 }
992
993 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
994 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
995 if (_young_gen->supports_tlab_allocation()) {
996 return _young_gen->unsafe_max_tlab_alloc();
997 }
998 return 0;
999 }
1000
1001 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1002 bool gc_overhead_limit_was_exceeded;
1003 return collector_policy()->mem_allocate_work(size /* size */,
1004 true /* is_tlab */,
1005 &gc_overhead_limit_was_exceeded);
1006 }
1007
1008 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1009 // from the list headed by "*prev_ptr".
1010 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1011 bool first = true;
1012 size_t min_size = 0; // "first" makes this conceptually infinite.
1013 ScratchBlock **smallest_ptr, *smallest;
1014 ScratchBlock *cur = *prev_ptr;
1015 while (cur) {
1016 assert(*prev_ptr == cur, "just checking");
1017 if (first || cur->num_words < min_size) {
1018 smallest_ptr = prev_ptr;
1019 smallest = cur;
1020 min_size = smallest->num_words;
1021 first = false;
1022 }
1023 prev_ptr = &cur->next;
1024 cur = cur->next;
1025 }
1026 smallest = *smallest_ptr;
1027 *smallest_ptr = smallest->next;
1028 return smallest;
1029 }
1030
1031 // Sort the scratch block list headed by res into decreasing size order,
1032 // and set "res" to the result.
1033 static void sort_scratch_list(ScratchBlock*& list) {
1034 ScratchBlock* sorted = NULL;
1035 ScratchBlock* unsorted = list;
1036 while (unsorted) {
1037 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1038 smallest->next = sorted;
1039 sorted = smallest;
1040 }
1041 list = sorted;
1042 }
1043
1044 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1045 size_t max_alloc_words) {
1046 ScratchBlock* res = NULL;
1047 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1048 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1049 sort_scratch_list(res);
1050 return res;
1051 }
1052
1053 void GenCollectedHeap::release_scratch() {
1054 _young_gen->reset_scratch();
1055 _old_gen->reset_scratch();
1056 }
1057
1058 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1059 void do_generation(Generation* gen) {
1060 gen->prepare_for_verify();
1061 }
1062 };
1063
1064 void GenCollectedHeap::prepare_for_verify() {
1065 ensure_parsability(false); // no need to retire TLABs
1066 GenPrepareForVerifyClosure blk;
1067 generation_iterate(&blk, false);
1068 }
1069
1070 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1071 bool old_to_young) {
1072 if (old_to_young) {
1073 cl->do_generation(_old_gen);
1074 cl->do_generation(_young_gen);
1075 } else {
1076 cl->do_generation(_young_gen);
1077 cl->do_generation(_old_gen);
1078 }
1079 }
1080
1081 bool GenCollectedHeap::is_maximal_no_gc() const {
1082 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1083 }
1084
1085 void GenCollectedHeap::save_marks() {
1086 _young_gen->save_marks();
1087 _old_gen->save_marks();
1088 }
1089
1090 GenCollectedHeap* GenCollectedHeap::heap() {
1091 CollectedHeap* heap = Universe::heap();
1092 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1093 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap");
1094 return (GenCollectedHeap*)heap;
1095 }
1096
1097 void GenCollectedHeap::prepare_for_compaction() {
1098 // Start by compacting into same gen.
1099 CompactPoint cp(_old_gen);
1100 _old_gen->prepare_for_compaction(&cp);
1101 _young_gen->prepare_for_compaction(&cp);
1102 }
1103
1104 GCStats* GenCollectedHeap::gc_stats(int level) const {
1105 if (level == 0) {
1106 return _young_gen->gc_stats();
1107 } else {
1108 return _old_gen->gc_stats();
1109 }
1110 }
1111
1112 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1113 if (!silent) {
1114 gclog_or_tty->print("%s", _old_gen->name());
1115 gclog_or_tty->print(" ");
1116 }
1117 _old_gen->verify();
1118
1119 if (!silent) {
1120 gclog_or_tty->print("%s", _young_gen->name());
1121 gclog_or_tty->print(" ");
1122 }
1123 _young_gen->verify();
1124
1125 if (!silent) {
1126 gclog_or_tty->print("remset ");
1127 }
1128 rem_set()->verify();
1129 }
1130
1131 void GenCollectedHeap::print_on(outputStream* st) const {
1132 _young_gen->print_on(st);
1133 _old_gen->print_on(st);
1134 MetaspaceAux::print_on(st);
1135 }
1136
1137 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1138 if (workers() != NULL) {
1139 workers()->threads_do(tc);
1140 }
1141 #if INCLUDE_ALL_GCS
1142 if (UseConcMarkSweepGC) {
1143 ConcurrentMarkSweepThread::threads_do(tc);
1144 }
1145 #endif // INCLUDE_ALL_GCS
1146 }
1147
1148 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1149 #if INCLUDE_ALL_GCS
1150 if (UseConcMarkSweepGC) {
1151 workers()->print_worker_threads_on(st);
1152 ConcurrentMarkSweepThread::print_all_on(st);
1153 }
1154 #endif // INCLUDE_ALL_GCS
1155 }
1156
1157 void GenCollectedHeap::print_on_error(outputStream* st) const {
1158 this->CollectedHeap::print_on_error(st);
1159
1160 #if INCLUDE_ALL_GCS
1161 if (UseConcMarkSweepGC) {
1162 st->cr();
1163 CMSCollector::print_on_error(st);
1164 }
1165 #endif // INCLUDE_ALL_GCS
1166 }
1167
1168 void GenCollectedHeap::print_tracing_info() const {
1169 if (TraceYoungGenTime) {
1170 _young_gen->print_summary_info();
1171 }
1172 if (TraceOldGenTime) {
1173 _old_gen->print_summary_info();
1174 }
1175 }
1176
1177 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1178 if (PrintGCDetails && Verbose) {
1179 gclog_or_tty->print(" " SIZE_FORMAT
1180 "->" SIZE_FORMAT
1181 "(" SIZE_FORMAT ")",
1182 prev_used, used(), capacity());
1183 } else {
1184 gclog_or_tty->print(" " SIZE_FORMAT "K"
1185 "->" SIZE_FORMAT "K"
1186 "(" SIZE_FORMAT "K)",
1187 prev_used / K, used() / K, capacity() / K);
1188 }
1189 }
1190
1191 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1192 private:
1193 bool _full;
1194 public:
1195 void do_generation(Generation* gen) {
1196 gen->gc_prologue(_full);
1197 }
1198 GenGCPrologueClosure(bool full) : _full(full) {};
1199 };
1200
1201 void GenCollectedHeap::gc_prologue(bool full) {
1202 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1203
1204 always_do_update_barrier = false;
1205 // Fill TLAB's and such
1206 CollectedHeap::accumulate_statistics_all_tlabs();
1207 ensure_parsability(true); // retire TLABs
1208
1209 // Walk generations
1210 GenGCPrologueClosure blk(full);
1211 generation_iterate(&blk, false); // not old-to-young.
1212 };
1213
1214 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1215 private:
1216 bool _full;
1217 public:
1218 void do_generation(Generation* gen) {
1219 gen->gc_epilogue(_full);
1220 }
1221 GenGCEpilogueClosure(bool full) : _full(full) {};
1222 };
1223
1224 void GenCollectedHeap::gc_epilogue(bool full) {
1225 #ifdef COMPILER2
1226 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1227 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1228 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1229 #endif /* COMPILER2 */
1230
1231 resize_all_tlabs();
1232
1233 GenGCEpilogueClosure blk(full);
1234 generation_iterate(&blk, false); // not old-to-young.
1235
1236 if (!CleanChunkPoolAsync) {
1237 Chunk::clean_chunk_pool();
1238 }
1239
1240 MetaspaceCounters::update_performance_counters();
1241 CompressedClassSpaceCounters::update_performance_counters();
1242
1243 always_do_update_barrier = UseConcMarkSweepGC;
1244 };
1245
1246 #ifndef PRODUCT
1247 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1248 private:
1249 public:
1250 void do_generation(Generation* gen) {
1251 gen->record_spaces_top();
1252 }
1253 };
1254
1255 void GenCollectedHeap::record_gen_tops_before_GC() {
1256 if (ZapUnusedHeapArea) {
1257 GenGCSaveTopsBeforeGCClosure blk;
1258 generation_iterate(&blk, false); // not old-to-young.
1259 }
1260 }
1261 #endif // not PRODUCT
1262
1263 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1264 public:
1265 void do_generation(Generation* gen) {
1266 gen->ensure_parsability();
1267 }
1268 };
1269
1270 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1271 CollectedHeap::ensure_parsability(retire_tlabs);
1272 GenEnsureParsabilityClosure ep_cl;
1273 generation_iterate(&ep_cl, false);
1274 }
1275
1276 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1277 oop obj,
1278 size_t obj_size) {
1279 guarantee(old_gen->level() == 1, "We only get here with an old generation");
1280 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1281 HeapWord* result = NULL;
1282
1283 result = old_gen->expand_and_allocate(obj_size, false);
1284
1285 if (result != NULL) {
1286 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1287 }
1288 return oop(result);
1289 }
1290
1291 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1292 jlong _time; // in ms
1293 jlong _now; // in ms
1294
1295 public:
1296 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1297
1298 jlong time() { return _time; }
1299
1300 void do_generation(Generation* gen) {
1301 _time = MIN2(_time, gen->time_of_last_gc(_now));
1302 }
1303 };
1304
1305 jlong GenCollectedHeap::millis_since_last_gc() {
1306 // We need a monotonically non-decreasing time in ms but
1307 // os::javaTimeMillis() does not guarantee monotonicity.
1308 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1309 GenTimeOfLastGCClosure tolgc_cl(now);
1310 // iterate over generations getting the oldest
1311 // time that a generation was collected
1312 generation_iterate(&tolgc_cl, false);
1313
1314 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1315 // provided the underlying platform provides such a time source
1316 // (and it is bug free). So we still have to guard against getting
1317 // back a time later than 'now'.
1318 jlong retVal = now - tolgc_cl.time();
1319 if (retVal < 0) {
1320 NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, retVal);)
1321 return 0;
1322 }
1323 return retVal;
1324 }