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_implementation/shared/collectorCounters.hpp"
32 #include "gc_implementation/shared/gcTrace.hpp"
33 #include "gc_implementation/shared/gcTraceTime.hpp"
34 #include "gc_implementation/shared/vmGCOperations.hpp"
35 #include "gc_interface/collectedHeap.inline.hpp"
36 #include "memory/filemap.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/genCollectedHeap.hpp"
39 #include "memory/genOopClosures.inline.hpp"
40 #include "memory/generationSpec.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "memory/strongRootsScope.hpp"
43 #include "memory/space.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "runtime/biasedLocking.hpp"
46 #include "runtime/fprofiler.hpp"
47 #include "runtime/handles.hpp"
48 #include "runtime/handles.inline.hpp"
49 #include "runtime/java.hpp"
50 #include "runtime/vmThread.hpp"
51 #include "services/management.hpp"
52 #include "services/memoryService.hpp"
53 #include "utilities/macros.hpp"
54 #include "utilities/stack.inline.hpp"
55 #include "utilities/vmError.hpp"
56 #include "utilities/workgroup.hpp"
57 #if INCLUDE_ALL_GCS
58 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
59 #include "gc_implementation/concurrentMarkSweep/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, 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, 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 void GenCollectedHeap::save_used_regions() {
206 _old_gen->save_used_region();
207 _young_gen->save_used_region();
208 }
209
210 size_t GenCollectedHeap::max_capacity() const {
211 return _young_gen->max_capacity() + _old_gen->max_capacity();
212 }
213
214 // Update the _full_collections_completed counter
215 // at the end of a stop-world full GC.
216 unsigned int GenCollectedHeap::update_full_collections_completed() {
217 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
218 assert(_full_collections_completed <= _total_full_collections,
219 "Can't complete more collections than were started");
220 _full_collections_completed = _total_full_collections;
221 ml.notify_all();
222 return _full_collections_completed;
223 }
224
225 // Update the _full_collections_completed counter, as appropriate,
226 // at the end of a concurrent GC cycle. Note the conditional update
227 // below to allow this method to be called by a concurrent collector
228 // without synchronizing in any manner with the VM thread (which
229 // may already have initiated a STW full collection "concurrently").
230 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
231 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
232 assert((_full_collections_completed <= _total_full_collections) &&
233 (count <= _total_full_collections),
234 "Can't complete more collections than were started");
235 if (count > _full_collections_completed) {
236 _full_collections_completed = count;
237 ml.notify_all();
238 }
239 return _full_collections_completed;
240 }
241
242
243 #ifndef PRODUCT
244 // Override of memory state checking method in CollectedHeap:
245 // Some collectors (CMS for example) can't have badHeapWordVal written
246 // in the first two words of an object. (For instance , in the case of
247 // CMS these words hold state used to synchronize between certain
248 // (concurrent) GC steps and direct allocating mutators.)
249 // The skip_header_HeapWords() method below, allows us to skip
250 // over the requisite number of HeapWord's. Note that (for
251 // generational collectors) this means that those many words are
252 // skipped in each object, irrespective of the generation in which
253 // that object lives. The resultant loss of precision seems to be
254 // harmless and the pain of avoiding that imprecision appears somewhat
255 // higher than we are prepared to pay for such rudimentary debugging
256 // support.
257 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
258 size_t size) {
259 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
260 // We are asked to check a size in HeapWords,
261 // but the memory is mangled in juint words.
262 juint* start = (juint*) (addr + skip_header_HeapWords());
263 juint* end = (juint*) (addr + size);
264 for (juint* slot = start; slot < end; slot += 1) {
265 assert(*slot == badHeapWordVal,
266 "Found non badHeapWordValue in pre-allocation check");
267 }
268 }
269 }
270 #endif
271
272 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
273 bool is_tlab,
274 bool first_only) {
275 HeapWord* res = NULL;
276
277 if (_young_gen->should_allocate(size, is_tlab)) {
278 res = _young_gen->allocate(size, is_tlab);
279 if (res != NULL || first_only) {
280 return res;
281 }
282 }
283
284 if (_old_gen->should_allocate(size, is_tlab)) {
285 res = _old_gen->allocate(size, is_tlab);
286 }
287
288 return res;
289 }
290
291 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
292 bool* gc_overhead_limit_was_exceeded) {
293 return collector_policy()->mem_allocate_work(size,
294 false /* is_tlab */,
295 gc_overhead_limit_was_exceeded);
296 }
297
298 bool GenCollectedHeap::must_clear_all_soft_refs() {
299 return _gc_cause == GCCause::_last_ditch_collection;
300 }
301
302 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
303 return UseConcMarkSweepGC &&
304 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
305 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
306 }
307
308 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
309 bool is_tlab, bool run_verification, bool clear_soft_refs,
310 bool restore_marks_for_biased_locking) {
311 // Timer for individual generations. Last argument is false: no CR
312 // FIXME: We should try to start the timing earlier to cover more of the GC pause
313 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
314 // so we can assume here that the next GC id is what we want.
315 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek());
316 TraceCollectorStats tcs(gen->counters());
317 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
318
319 size_t prev_used = gen->used();
320 gen->stat_record()->invocations++;
321 gen->stat_record()->accumulated_time.start();
322
323 // Must be done anew before each collection because
324 // a previous collection will do mangling and will
325 // change top of some spaces.
326 record_gen_tops_before_GC();
327
328 if (PrintGC && Verbose) {
329 // I didn't want to change the logging when removing the level concept,
330 // but I guess this logging could say young/old or something instead of 0/1.
331 uint level;
332 if (gen == GenCollectedHeap::heap()->young_gen()) {
333 level = 0;
334 } else {
335 level = 1;
336 }
337 gclog_or_tty->print("level=%u invoke=%d size=" SIZE_FORMAT,
338 level,
339 gen->stat_record()->invocations,
340 size * HeapWordSize);
341 }
342
343 if (run_verification && VerifyBeforeGC) {
344 HandleMark hm; // Discard invalid handles created during verification
345 Universe::verify(" VerifyBeforeGC:");
346 }
347 COMPILER2_PRESENT(DerivedPointerTable::clear());
348
349 if (restore_marks_for_biased_locking) {
350 // We perform this mark word preservation work lazily
351 // because it's only at this point that we know whether we
352 // absolutely have to do it; we want to avoid doing it for
353 // scavenge-only collections where it's unnecessary
354 BiasedLocking::preserve_marks();
355 }
356
357 // Do collection work
358 {
359 // Note on ref discovery: For what appear to be historical reasons,
360 // GCH enables and disabled (by enqueing) refs discovery.
361 // In the future this should be moved into the generation's
362 // collect method so that ref discovery and enqueueing concerns
363 // are local to a generation. The collect method could return
364 // an appropriate indication in the case that notification on
365 // the ref lock was needed. This will make the treatment of
366 // weak refs more uniform (and indeed remove such concerns
367 // from GCH). XXX
368
369 HandleMark hm; // Discard invalid handles created during gc
370 save_marks(); // save marks for all gens
371 // We want to discover references, but not process them yet.
372 // This mode is disabled in process_discovered_references if the
373 // generation does some collection work, or in
374 // enqueue_discovered_references if the generation returns
375 // without doing any work.
376 ReferenceProcessor* rp = gen->ref_processor();
377 // If the discovery of ("weak") refs in this generation is
378 // atomic wrt other collectors in this configuration, we
379 // are guaranteed to have empty discovered ref lists.
380 if (rp->discovery_is_atomic()) {
381 rp->enable_discovery();
382 rp->setup_policy(clear_soft_refs);
383 } else {
384 // collect() below will enable discovery as appropriate
385 }
386 gen->collect(full, clear_soft_refs, size, is_tlab);
387 if (!rp->enqueuing_is_done()) {
388 rp->enqueue_discovered_references();
389 } else {
390 rp->set_enqueuing_is_done(false);
391 }
392 rp->verify_no_references_recorded();
393 }
394
395 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
396
397 gen->stat_record()->accumulated_time.stop();
398
399 update_gc_stats(gen, full);
400
401 if (run_verification && VerifyAfterGC) {
402 HandleMark hm; // Discard invalid handles created during verification
403 Universe::verify(" VerifyAfterGC:");
404 }
405
406 if (PrintGCDetails) {
407 gclog_or_tty->print(":");
408 gen->print_heap_change(prev_used);
409 }
410 }
411
412 void GenCollectedHeap::do_collection(bool full,
413 bool clear_all_soft_refs,
414 size_t size,
415 bool is_tlab,
416 Generation::Type max_generation) {
417 ResourceMark rm;
418 DEBUG_ONLY(Thread* my_thread = Thread::current();)
419
420 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
421 assert(my_thread->is_VM_thread() ||
422 my_thread->is_ConcurrentGC_thread(),
423 "incorrect thread type capability");
424 assert(Heap_lock->is_locked(),
425 "the requesting thread should have the Heap_lock");
426 guarantee(!is_gc_active(), "collection is not reentrant");
427
428 if (GC_locker::check_active_before_gc()) {
429 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
430 }
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 == Generation::Old);
445 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
446 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
447 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
448 // so we can assume here that the next GC id is what we want.
449 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
450
451 gc_prologue(complete);
452 increment_total_collections(complete);
453
454 size_t gch_prev_used = used();
455 bool run_verification = total_collections() >= VerifyGCStartAt;
456
457 bool prepared_for_verification = false;
458 bool collected_old = false;
459 bool old_collects_young = complete &&
460 _old_gen->full_collects_younger_generations();
461 if (!old_collects_young &&
462 _young_gen->should_collect(full, size, is_tlab)) {
463 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
464 prepare_for_verify();
465 prepared_for_verification = true;
466 }
467
468 assert(!_young_gen->performs_in_place_marking(), "No young generation do in place marking");
469 collect_generation(_young_gen,
470 full,
471 size,
472 is_tlab,
473 run_verification && VerifyGCLevel <= 0,
474 do_clear_all_soft_refs,
475 false);
476
477 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
478 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
479 // Allocation request was met by young GC.
480 size = 0;
481 }
482 }
483
484 bool must_restore_marks_for_biased_locking = false;
485
486 if (max_generation == Generation::Old && _old_gen->should_collect(full, size, is_tlab)) {
487 if (!complete) {
488 // The full_collections increment was missed above.
489 increment_total_full_collections();
490 }
491
492 pre_full_gc_dump(NULL); // do any pre full gc dumps
493
494 if (!prepared_for_verification && run_verification &&
495 VerifyGCLevel <= 1 && VerifyBeforeGC) {
496 prepare_for_verify();
497 }
498
499 assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking");
500 collect_generation(_old_gen,
501 full,
502 size,
503 is_tlab,
504 run_verification && VerifyGCLevel <= 1,
505 do_clear_all_soft_refs,
506 true);
507
508 must_restore_marks_for_biased_locking = true;
509 collected_old = true;
510 }
511
512 // Update "complete" boolean wrt what actually transpired --
513 // for instance, a promotion failure could have led to
514 // a whole heap collection.
515 complete = complete || collected_old;
516
517 if (complete) { // We did a "major" collection
518 // FIXME: See comment at pre_full_gc_dump call
519 post_full_gc_dump(NULL); // do any post full gc dumps
520 }
521
522 if (PrintGCDetails) {
523 print_heap_change(gch_prev_used);
524
525 // Print metaspace info for full GC with PrintGCDetails flag.
526 if (complete) {
527 MetaspaceAux::print_metaspace_change(metadata_prev_used);
528 }
529 }
530
531 // Adjust generation sizes.
532 if (collected_old) {
533 _old_gen->compute_new_size();
534 }
535 _young_gen->compute_new_size();
536
537 if (complete) {
538 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
539 ClassLoaderDataGraph::purge();
540 MetaspaceAux::verify_metrics();
541 // Resize the metaspace capacity after full collections
542 MetaspaceGC::compute_new_size();
543 update_full_collections_completed();
544 }
545
546 // Track memory usage and detect low memory after GC finishes
547 MemoryService::track_memory_usage();
548
549 gc_epilogue(complete);
550
551 if (must_restore_marks_for_biased_locking) {
552 BiasedLocking::restore_marks();
553 }
554 }
555
556 print_heap_after_gc();
557
558 #ifdef TRACESPINNING
559 ParallelTaskTerminator::print_termination_counts();
560 #endif
561 }
562
563 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
564 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
565 }
566
567 void GenCollectedHeap::set_par_threads(uint t) {
568 assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
569 CollectedHeap::set_par_threads(t);
570 set_n_termination(t);
571 }
572
573 void GenCollectedHeap::set_n_termination(uint t) {
574 _process_strong_tasks->set_n_threads(t);
575 }
576
577 #ifdef ASSERT
578 class AssertNonScavengableClosure: public OopClosure {
579 public:
580 virtual void do_oop(oop* p) {
581 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
582 "Referent should not be scavengable."); }
583 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
584 };
585 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
586 #endif
587
588 void GenCollectedHeap::process_roots(bool activate_scope,
589 ScanningOption so,
590 OopClosure* strong_roots,
591 OopClosure* weak_roots,
592 CLDClosure* strong_cld_closure,
593 CLDClosure* weak_cld_closure,
594 CodeBlobClosure* code_roots) {
595 StrongRootsScope srs(activate_scope);
596
597 // General roots.
598 assert(Threads::thread_claim_parity() != 0, "must have called prologue code");
599 assert(code_roots != NULL, "code root closure should always be set");
600 // _n_termination for _process_strong_tasks should be set up stream
601 // in a method not running in a GC worker. Otherwise the GC worker
602 // could be trying to change the termination condition while the task
603 // is executing in another GC worker.
604
605 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
606 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
607 }
608
609 // Some CLDs contained in the thread frames should be considered strong.
610 // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
611 CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
612 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
613 CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
614
615 bool is_par = n_par_threads() > 0;
616 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_clds_p, roots_from_code_p);
617
618 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
619 Universe::oops_do(strong_roots);
620 }
621 // Global (strong) JNI handles
622 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
623 JNIHandles::oops_do(strong_roots);
624 }
625
626 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
627 ObjectSynchronizer::oops_do(strong_roots);
628 }
629 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
630 FlatProfiler::oops_do(strong_roots);
631 }
632 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
633 Management::oops_do(strong_roots);
634 }
635 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
636 JvmtiExport::oops_do(strong_roots);
637 }
638
639 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
640 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
641 }
642
643 // All threads execute the following. A specific chunk of buckets
644 // from the StringTable are the individual tasks.
645 if (weak_roots != NULL) {
646 if (is_par) {
647 StringTable::possibly_parallel_oops_do(weak_roots);
648 } else {
649 StringTable::oops_do(weak_roots);
650 }
651 }
652
653 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
654 if (so & SO_ScavengeCodeCache) {
655 assert(code_roots != NULL, "must supply closure for code cache");
656
657 // We only visit parts of the CodeCache when scavenging.
658 CodeCache::scavenge_root_nmethods_do(code_roots);
659 }
660 if (so & SO_AllCodeCache) {
661 assert(code_roots != NULL, "must supply closure for code cache");
662
663 // CMSCollector uses this to do intermediate-strength collections.
664 // We scan the entire code cache, since CodeCache::do_unloading is not called.
665 CodeCache::blobs_do(code_roots);
666 }
667 // Verify that the code cache contents are not subject to
668 // movement by a scavenging collection.
669 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
670 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
671 }
672
673 }
674
675 void GenCollectedHeap::gen_process_roots(Generation::Type type,
676 bool younger_gens_as_roots,
677 bool activate_scope,
678 ScanningOption so,
679 bool only_strong_roots,
680 OopsInGenClosure* not_older_gens,
681 OopsInGenClosure* older_gens,
682 CLDClosure* cld_closure) {
683 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
684
685 bool is_moving_collection = false;
686 if (type == Generation::Young || is_adjust_phase) {
687 // young collections are always moving
688 is_moving_collection = true;
689 }
690
691 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
692 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : not_older_gens;
693 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
694
695 process_roots(activate_scope, so,
696 not_older_gens, weak_roots,
697 cld_closure, weak_cld_closure,
698 &mark_code_closure);
699
700 if (younger_gens_as_roots) {
701 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
702 if (type == Generation::Old) {
703 not_older_gens->set_generation(_young_gen);
704 _young_gen->oop_iterate(not_older_gens);
705 }
706 not_older_gens->reset_generation();
707 }
708 }
709 // When collection is parallel, all threads get to cooperate to do
710 // old generation scanning.
711 if (type == Generation::Young) {
712 older_gens->set_generation(_old_gen);
713 rem_set()->younger_refs_iterate(_old_gen, older_gens);
714 older_gens->reset_generation();
715 }
716
717 _process_strong_tasks->all_tasks_completed();
718 }
719
720
721 class AlwaysTrueClosure: public BoolObjectClosure {
722 public:
723 bool do_object_b(oop p) { return true; }
724 };
725 static AlwaysTrueClosure always_true;
726
727 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
728 JNIHandles::weak_oops_do(&always_true, 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(Generation::Type gen, \
736 OopClosureType* cur, \
737 OopClosureType* older) { \
738 if (gen == Generation::Young) { \
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(bool include_young) {
751 if (include_young && !_young_gen->no_allocs_since_save_marks()) {
752 return false;
753 }
754 return _old_gen->no_allocs_since_save_marks();
755 }
756
757 bool GenCollectedHeap::supports_inline_contig_alloc() const {
758 return _young_gen->supports_inline_contig_alloc();
759 }
760
761 HeapWord** GenCollectedHeap::top_addr() const {
762 return _young_gen->top_addr();
763 }
764
765 HeapWord** GenCollectedHeap::end_addr() const {
766 return _young_gen->end_addr();
767 }
768
769 // public collection interfaces
770
771 void GenCollectedHeap::collect(GCCause::Cause cause) {
772 if (should_do_concurrent_full_gc(cause)) {
773 #if INCLUDE_ALL_GCS
774 // mostly concurrent full collection
775 collect_mostly_concurrent(cause);
776 #else // INCLUDE_ALL_GCS
777 ShouldNotReachHere();
778 #endif // INCLUDE_ALL_GCS
779 } else if (cause == GCCause::_wb_young_gc) {
780 // minor collection for WhiteBox API
781 collect(cause, Generation::Young);
782 } else {
783 #ifdef ASSERT
784 if (cause == GCCause::_scavenge_alot) {
785 // minor collection only
786 collect(cause, Generation::Young);
787 } else {
788 // Stop-the-world full collection
789 collect(cause, Generation::Old);
790 }
791 #else
792 // Stop-the-world full collection
793 collect(cause, Generation::Old);
794 #endif
795 }
796 }
797
798 void GenCollectedHeap::collect(GCCause::Cause cause, Generation::Type max_generation) {
799 // The caller doesn't have the Heap_lock
800 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
801 MutexLocker ml(Heap_lock);
802 collect_locked(cause, max_generation);
803 }
804
805 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
806 // The caller has the Heap_lock
807 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
808 collect_locked(cause, Generation::Old);
809 }
810
811 // this is the private collection interface
812 // The Heap_lock is expected to be held on entry.
813
814 void GenCollectedHeap::collect_locked(GCCause::Cause cause, Generation::Type max_generation) {
815 // Read the GC count while holding the Heap_lock
816 unsigned int gc_count_before = total_collections();
817 unsigned int full_gc_count_before = total_full_collections();
818 {
819 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
820 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
821 cause, max_generation);
822 VMThread::execute(&op);
823 }
824 }
825
826 #if INCLUDE_ALL_GCS
827 bool GenCollectedHeap::create_cms_collector() {
828
829 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
830 "Unexpected generation kinds");
831 // Skip two header words in the block content verification
832 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
833 CMSCollector* collector = new CMSCollector(
834 (ConcurrentMarkSweepGeneration*)_old_gen,
835 _rem_set->as_CardTableRS(),
836 (ConcurrentMarkSweepPolicy*) collector_policy());
837
838 if (collector == NULL || !collector->completed_initialization()) {
839 if (collector) {
840 delete collector; // Be nice in embedded situation
841 }
842 vm_shutdown_during_initialization("Could not create CMS collector");
843 return false;
844 }
845 return true; // success
846 }
847
848 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
849 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
850
851 MutexLocker ml(Heap_lock);
852 // Read the GC counts while holding the Heap_lock
853 unsigned int full_gc_count_before = total_full_collections();
854 unsigned int gc_count_before = total_collections();
855 {
856 MutexUnlocker mu(Heap_lock);
857 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
858 VMThread::execute(&op);
859 }
860 }
861 #endif // INCLUDE_ALL_GCS
862
863 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
864 do_full_collection(clear_all_soft_refs, Generation::Old);
865 }
866
867 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
868 Generation::Type last_generation) {
869 Generation::Type local_last_generation;
870 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
871 gc_cause() == GCCause::_gc_locker) {
872 local_last_generation = Generation::Young;
873 } else {
874 local_last_generation = last_generation;
875 }
876
877 do_collection(true /* full */,
878 clear_all_soft_refs /* clear_all_soft_refs */,
879 0 /* size */,
880 false /* is_tlab */,
881 local_last_generation /* last_generation */);
882 // Hack XXX FIX ME !!!
883 // A scavenge may not have been attempted, or may have
884 // been attempted and failed, because the old gen was too full
885 if (local_last_generation == Generation::Young && gc_cause() == GCCause::_gc_locker &&
886 incremental_collection_will_fail(false /* don't consult_young */)) {
887 if (PrintGCDetails) {
888 gclog_or_tty->print_cr("GC locker: Trying a full collection "
889 "because scavenge failed");
890 }
891 // This time allow the old gen to be collected as well
892 do_collection(true /* full */,
893 clear_all_soft_refs /* clear_all_soft_refs */,
894 0 /* size */,
895 false /* is_tlab */,
896 Generation::Old /* last_generation */);
897 }
898 }
899
900 bool GenCollectedHeap::is_in_young(oop p) {
901 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
902 assert(result == _young_gen->is_in_reserved(p),
903 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
904 return result;
905 }
906
907 // Returns "TRUE" iff "p" points into the committed areas of the heap.
908 bool GenCollectedHeap::is_in(const void* p) const {
909 return _young_gen->is_in(p) || _old_gen->is_in(p);
910 }
911
912 #ifdef ASSERT
913 // Don't implement this by using is_in_young(). This method is used
914 // in some cases to check that is_in_young() is correct.
915 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
916 assert(is_in_reserved(p) || p == NULL,
917 "Does not work if address is non-null and outside of the heap");
918 return p < _young_gen->reserved().end() && p != NULL;
919 }
920 #endif
921
922 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) {
923 NoHeaderExtendedOopClosure no_header_cl(cl);
924 oop_iterate(&no_header_cl);
925 }
926
927 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
928 _young_gen->oop_iterate(cl);
929 _old_gen->oop_iterate(cl);
930 }
931
932 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
933 _young_gen->object_iterate(cl);
934 _old_gen->object_iterate(cl);
935 }
936
937 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
938 _young_gen->safe_object_iterate(cl);
939 _old_gen->safe_object_iterate(cl);
940 }
941
942 Space* GenCollectedHeap::space_containing(const void* addr) const {
943 Space* res = _young_gen->space_containing(addr);
944 if (res != NULL) {
945 return res;
946 }
947 res = _old_gen->space_containing(addr);
948 assert(res != NULL, "Could not find containing space");
949 return res;
950 }
951
952 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
953 assert(is_in_reserved(addr), "block_start of address outside of heap");
954 if (_young_gen->is_in_reserved(addr)) {
955 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
956 return _young_gen->block_start(addr);
957 }
958
959 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
960 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
961 return _old_gen->block_start(addr);
962 }
963
964 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
965 assert(is_in_reserved(addr), "block_size of address outside of heap");
966 if (_young_gen->is_in_reserved(addr)) {
967 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
968 return _young_gen->block_size(addr);
969 }
970
971 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
972 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
973 return _old_gen->block_size(addr);
974 }
975
976 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
977 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
978 assert(block_start(addr) == addr, "addr must be a block start");
979 if (_young_gen->is_in_reserved(addr)) {
980 return _young_gen->block_is_obj(addr);
981 }
982
983 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
984 return _old_gen->block_is_obj(addr);
985 }
986
987 bool GenCollectedHeap::supports_tlab_allocation() const {
988 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
989 return _young_gen->supports_tlab_allocation();
990 }
991
992 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
993 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
994 if (_young_gen->supports_tlab_allocation()) {
995 return _young_gen->tlab_capacity();
996 }
997 return 0;
998 }
999
1000 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1001 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1002 if (_young_gen->supports_tlab_allocation()) {
1003 return _young_gen->tlab_used();
1004 }
1005 return 0;
1006 }
1007
1008 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1009 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1010 if (_young_gen->supports_tlab_allocation()) {
1011 return _young_gen->unsafe_max_tlab_alloc();
1012 }
1013 return 0;
1014 }
1015
1016 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1017 bool gc_overhead_limit_was_exceeded;
1018 return collector_policy()->mem_allocate_work(size /* size */,
1019 true /* is_tlab */,
1020 &gc_overhead_limit_was_exceeded);
1021 }
1022
1023 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1024 // from the list headed by "*prev_ptr".
1025 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1026 bool first = true;
1027 size_t min_size = 0; // "first" makes this conceptually infinite.
1028 ScratchBlock **smallest_ptr, *smallest;
1029 ScratchBlock *cur = *prev_ptr;
1030 while (cur) {
1031 assert(*prev_ptr == cur, "just checking");
1032 if (first || cur->num_words < min_size) {
1033 smallest_ptr = prev_ptr;
1034 smallest = cur;
1035 min_size = smallest->num_words;
1036 first = false;
1037 }
1038 prev_ptr = &cur->next;
1039 cur = cur->next;
1040 }
1041 smallest = *smallest_ptr;
1042 *smallest_ptr = smallest->next;
1043 return smallest;
1044 }
1045
1046 // Sort the scratch block list headed by res into decreasing size order,
1047 // and set "res" to the result.
1048 static void sort_scratch_list(ScratchBlock*& list) {
1049 ScratchBlock* sorted = NULL;
1050 ScratchBlock* unsorted = list;
1051 while (unsorted) {
1052 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1053 smallest->next = sorted;
1054 sorted = smallest;
1055 }
1056 list = sorted;
1057 }
1058
1059 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1060 size_t max_alloc_words) {
1061 ScratchBlock* res = NULL;
1062 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1063 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1064 sort_scratch_list(res);
1065 return res;
1066 }
1067
1068 void GenCollectedHeap::release_scratch() {
1069 _young_gen->reset_scratch();
1070 _old_gen->reset_scratch();
1071 }
1072
1073 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1074 void do_generation(Generation* gen) {
1075 gen->prepare_for_verify();
1076 }
1077 };
1078
1079 void GenCollectedHeap::prepare_for_verify() {
1080 ensure_parsability(false); // no need to retire TLABs
1081 GenPrepareForVerifyClosure blk;
1082 generation_iterate(&blk, false);
1083 }
1084
1085 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1086 bool old_to_young) {
1087 if (old_to_young) {
1088 cl->do_generation(_old_gen);
1089 cl->do_generation(_young_gen);
1090 } else {
1091 cl->do_generation(_young_gen);
1092 cl->do_generation(_old_gen);
1093 }
1094 }
1095
1096 bool GenCollectedHeap::is_maximal_no_gc() const {
1097 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1098 }
1099
1100 void GenCollectedHeap::save_marks() {
1101 _young_gen->save_marks();
1102 _old_gen->save_marks();
1103 }
1104
1105 GenCollectedHeap* GenCollectedHeap::heap() {
1106 CollectedHeap* heap = Universe::heap();
1107 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1108 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap");
1109 return (GenCollectedHeap*)heap;
1110 }
1111
1112 void GenCollectedHeap::prepare_for_compaction() {
1113 // Start by compacting into same gen.
1114 CompactPoint cp(_old_gen);
1115 _old_gen->prepare_for_compaction(&cp);
1116 _young_gen->prepare_for_compaction(&cp);
1117 }
1118
1119 GCStats* GenCollectedHeap::gc_stats(Generation* gen) const {
1120 return gen->gc_stats();
1121 }
1122
1123 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1124 if (!silent) {
1125 gclog_or_tty->print("%s", _old_gen->name());
1126 gclog_or_tty->print(" ");
1127 }
1128 _old_gen->verify();
1129
1130 if (!silent) {
1131 gclog_or_tty->print("%s", _young_gen->name());
1132 gclog_or_tty->print(" ");
1133 }
1134 _young_gen->verify();
1135
1136 if (!silent) {
1137 gclog_or_tty->print("remset ");
1138 }
1139 rem_set()->verify();
1140 }
1141
1142 void GenCollectedHeap::print_on(outputStream* st) const {
1143 _young_gen->print_on(st);
1144 _old_gen->print_on(st);
1145 MetaspaceAux::print_on(st);
1146 }
1147
1148 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1149 if (workers() != NULL) {
1150 workers()->threads_do(tc);
1151 }
1152 #if INCLUDE_ALL_GCS
1153 if (UseConcMarkSweepGC) {
1154 ConcurrentMarkSweepThread::threads_do(tc);
1155 }
1156 #endif // INCLUDE_ALL_GCS
1157 }
1158
1159 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1160 #if INCLUDE_ALL_GCS
1161 if (UseConcMarkSweepGC) {
1162 workers()->print_worker_threads_on(st);
1163 ConcurrentMarkSweepThread::print_all_on(st);
1164 }
1165 #endif // INCLUDE_ALL_GCS
1166 }
1167
1168 void GenCollectedHeap::print_on_error(outputStream* st) const {
1169 this->CollectedHeap::print_on_error(st);
1170
1171 #if INCLUDE_ALL_GCS
1172 if (UseConcMarkSweepGC) {
1173 st->cr();
1174 CMSCollector::print_on_error(st);
1175 }
1176 #endif // INCLUDE_ALL_GCS
1177 }
1178
1179 void GenCollectedHeap::print_tracing_info() const {
1180 if (TraceYoungGenTime) {
1181 _young_gen->print_summary_info();
1182 }
1183 if (TraceOldGenTime) {
1184 _old_gen->print_summary_info();
1185 }
1186 }
1187
1188 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1189 if (PrintGCDetails && Verbose) {
1190 gclog_or_tty->print(" " SIZE_FORMAT
1191 "->" SIZE_FORMAT
1192 "(" SIZE_FORMAT ")",
1193 prev_used, used(), capacity());
1194 } else {
1195 gclog_or_tty->print(" " SIZE_FORMAT "K"
1196 "->" SIZE_FORMAT "K"
1197 "(" SIZE_FORMAT "K)",
1198 prev_used / K, used() / K, capacity() / K);
1199 }
1200 }
1201
1202 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1203 private:
1204 bool _full;
1205 public:
1206 void do_generation(Generation* gen) {
1207 gen->gc_prologue(_full);
1208 }
1209 GenGCPrologueClosure(bool full) : _full(full) {};
1210 };
1211
1212 void GenCollectedHeap::gc_prologue(bool full) {
1213 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1214
1215 always_do_update_barrier = false;
1216 // Fill TLAB's and such
1217 CollectedHeap::accumulate_statistics_all_tlabs();
1218 ensure_parsability(true); // retire TLABs
1219
1220 // Walk generations
1221 GenGCPrologueClosure blk(full);
1222 generation_iterate(&blk, false); // not old-to-young.
1223 };
1224
1225 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1226 private:
1227 bool _full;
1228 public:
1229 void do_generation(Generation* gen) {
1230 gen->gc_epilogue(_full);
1231 }
1232 GenGCEpilogueClosure(bool full) : _full(full) {};
1233 };
1234
1235 void GenCollectedHeap::gc_epilogue(bool full) {
1236 #ifdef COMPILER2
1237 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1238 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1239 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1240 #endif /* COMPILER2 */
1241
1242 resize_all_tlabs();
1243
1244 GenGCEpilogueClosure blk(full);
1245 generation_iterate(&blk, false); // not old-to-young.
1246
1247 if (!CleanChunkPoolAsync) {
1248 Chunk::clean_chunk_pool();
1249 }
1250
1251 MetaspaceCounters::update_performance_counters();
1252 CompressedClassSpaceCounters::update_performance_counters();
1253
1254 always_do_update_barrier = UseConcMarkSweepGC;
1255 };
1256
1257 #ifndef PRODUCT
1258 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1259 private:
1260 public:
1261 void do_generation(Generation* gen) {
1262 gen->record_spaces_top();
1263 }
1264 };
1265
1266 void GenCollectedHeap::record_gen_tops_before_GC() {
1267 if (ZapUnusedHeapArea) {
1268 GenGCSaveTopsBeforeGCClosure blk;
1269 generation_iterate(&blk, false); // not old-to-young.
1270 }
1271 }
1272 #endif // not PRODUCT
1273
1274 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1275 public:
1276 void do_generation(Generation* gen) {
1277 gen->ensure_parsability();
1278 }
1279 };
1280
1281 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1282 CollectedHeap::ensure_parsability(retire_tlabs);
1283 GenEnsureParsabilityClosure ep_cl;
1284 generation_iterate(&ep_cl, false);
1285 }
1286
1287 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1288 oop obj,
1289 size_t obj_size) {
1290 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1291 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1292 HeapWord* result = NULL;
1293
1294 result = old_gen->expand_and_allocate(obj_size, false);
1295
1296 if (result != NULL) {
1297 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1298 }
1299 return oop(result);
1300 }
1301
1302 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1303 jlong _time; // in ms
1304 jlong _now; // in ms
1305
1306 public:
1307 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1308
1309 jlong time() { return _time; }
1310
1311 void do_generation(Generation* gen) {
1312 _time = MIN2(_time, gen->time_of_last_gc(_now));
1313 }
1314 };
1315
1316 jlong GenCollectedHeap::millis_since_last_gc() {
1317 // We need a monotonically non-decreasing time in ms but
1318 // os::javaTimeMillis() does not guarantee monotonicity.
1319 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1320 GenTimeOfLastGCClosure tolgc_cl(now);
1321 // iterate over generations getting the oldest
1322 // time that a generation was collected
1323 generation_iterate(&tolgc_cl, false);
1324
1325 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1326 // provided the underlying platform provides such a time source
1327 // (and it is bug free). So we still have to guard against getting
1328 // back a time later than 'now'.
1329 jlong retVal = now - tolgc_cl.time();
1330 if (retVal < 0) {
1331 NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, retVal);)
1332 return 0;
1333 }
1334 return retVal;
1335 }