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/sharedHeap.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/vmError.hpp"
54 #include "utilities/workgroup.hpp"
55 #include "utilities/macros.hpp"
56 #if INCLUDE_ALL_GCS
57 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
58 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp"
59 #endif // INCLUDE_ALL_GCS
60
61 GenCollectedHeap* GenCollectedHeap::_gch;
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 SharedHeap(policy),
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 }
89
90 jint GenCollectedHeap::initialize() {
91 CollectedHeap::pre_initialize();
92
93 // While there are no constraints in the GC code that HeapWordSize
94 // be any particular value, there are multiple other areas in the
95 // system which believe this to be true (e.g. oop->object_size in some
96 // cases incorrectly returns the size in wordSize units rather than
97 // HeapWordSize).
98 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
99
100 // Allocate space for the heap.
101
102 char* heap_address;
103 ReservedSpace heap_rs;
104
105 size_t heap_alignment = collector_policy()->heap_alignment();
106
107 heap_address = allocate(heap_alignment, &heap_rs);
108
109 if (!heap_rs.is_reserved()) {
110 vm_shutdown_during_initialization(
111 "Could not reserve enough space for object heap");
112 return JNI_ENOMEM;
113 }
114
115 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
116
117 _rem_set = collector_policy()->create_rem_set(reserved_region());
118 set_barrier_set(rem_set()->bs());
119
120 _gch = this;
121
122 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false);
123 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, 0, rem_set());
124 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size());
125
126 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false);
127 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, 1, rem_set());
128 clear_incremental_collection_failed();
129
130 #if INCLUDE_ALL_GCS
131 // If we are running CMS, create the collector responsible
132 // for collecting the CMS generations.
133 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
134 bool success = create_cms_collector();
135 if (!success) return JNI_ENOMEM;
136 }
137 #endif // INCLUDE_ALL_GCS
138
139 return JNI_OK;
140 }
141
142 char* GenCollectedHeap::allocate(size_t alignment,
143 ReservedSpace* heap_rs){
144 // Now figure out the total size.
145 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
146 assert(alignment % pageSize == 0, "Must be");
147
148 GenerationSpec* young_spec = gen_policy()->young_gen_spec();
149 GenerationSpec* old_spec = gen_policy()->old_gen_spec();
150
151 // Check for overflow.
152 size_t total_reserved = young_spec->max_size() + old_spec->max_size();
153 if (total_reserved < young_spec->max_size()) {
154 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
155 "the maximum representable size");
156 }
157 assert(total_reserved % alignment == 0,
158 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
159 SIZE_FORMAT, total_reserved, alignment));
160
161 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
162 return heap_rs->base();
163 }
164
165 void GenCollectedHeap::post_initialize() {
166 SharedHeap::post_initialize();
167 GenCollectorPolicy *policy = (GenCollectorPolicy *)collector_policy();
168 guarantee(policy->is_generation_policy(), "Illegal policy type");
169 assert((_young_gen->kind() == Generation::DefNew) ||
170 (_young_gen->kind() == Generation::ParNew),
171 "Wrong youngest generation type");
172 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
173
174 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep ||
175 _old_gen->kind() == Generation::MarkSweepCompact,
176 "Wrong generation kind");
177
178 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
179 _old_gen->capacity(),
180 def_new_gen->from()->capacity());
181 policy->initialize_gc_policy_counters();
182 }
183
184 void GenCollectedHeap::ref_processing_init() {
185 SharedHeap::ref_processing_init();
186 _young_gen->ref_processor_init();
187 _old_gen->ref_processor_init();
188 }
189
190 size_t GenCollectedHeap::capacity() const {
191 return _young_gen->capacity() + _old_gen->capacity();
192 }
193
194 size_t GenCollectedHeap::used() const {
195 return _young_gen->used() + _old_gen->used();
196 }
197
198 // Save the "used_region" for generations level and lower.
199 void GenCollectedHeap::save_used_regions(int level) {
200 assert(level == 0 || level == 1, "Illegal level parameter");
201 if (level == 1) {
202 _old_gen->save_used_region();
203 }
204 _young_gen->save_used_region();
205 }
206
207 size_t GenCollectedHeap::max_capacity() const {
208 return _young_gen->max_capacity() + _old_gen->max_capacity();
209 }
210
211 // Update the _full_collections_completed counter
212 // at the end of a stop-world full GC.
213 unsigned int GenCollectedHeap::update_full_collections_completed() {
214 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
215 assert(_full_collections_completed <= _total_full_collections,
216 "Can't complete more collections than were started");
217 _full_collections_completed = _total_full_collections;
218 ml.notify_all();
219 return _full_collections_completed;
220 }
221
222 // Update the _full_collections_completed counter, as appropriate,
223 // at the end of a concurrent GC cycle. Note the conditional update
224 // below to allow this method to be called by a concurrent collector
225 // without synchronizing in any manner with the VM thread (which
226 // may already have initiated a STW full collection "concurrently").
227 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
228 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
229 assert((_full_collections_completed <= _total_full_collections) &&
230 (count <= _total_full_collections),
231 "Can't complete more collections than were started");
232 if (count > _full_collections_completed) {
233 _full_collections_completed = count;
234 ml.notify_all();
235 }
236 return _full_collections_completed;
237 }
238
239
240 #ifndef PRODUCT
241 // Override of memory state checking method in CollectedHeap:
242 // Some collectors (CMS for example) can't have badHeapWordVal written
243 // in the first two words of an object. (For instance , in the case of
244 // CMS these words hold state used to synchronize between certain
245 // (concurrent) GC steps and direct allocating mutators.)
246 // The skip_header_HeapWords() method below, allows us to skip
247 // over the requisite number of HeapWord's. Note that (for
248 // generational collectors) this means that those many words are
249 // skipped in each object, irrespective of the generation in which
250 // that object lives. The resultant loss of precision seems to be
251 // harmless and the pain of avoiding that imprecision appears somewhat
252 // higher than we are prepared to pay for such rudimentary debugging
253 // support.
254 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
255 size_t size) {
256 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
257 // We are asked to check a size in HeapWords,
258 // but the memory is mangled in juint words.
259 juint* start = (juint*) (addr + skip_header_HeapWords());
260 juint* end = (juint*) (addr + size);
261 for (juint* slot = start; slot < end; slot += 1) {
262 assert(*slot == badHeapWordVal,
263 "Found non badHeapWordValue in pre-allocation check");
264 }
265 }
266 }
267 #endif
268
269 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
270 bool is_tlab,
271 bool first_only) {
272 HeapWord* res = NULL;
273
274 if (_young_gen->should_allocate(size, is_tlab)) {
275 res = _young_gen->allocate(size, is_tlab);
276 if (res != NULL || first_only) {
277 return res;
278 }
279 }
280
281 if (_old_gen->should_allocate(size, is_tlab)) {
282 res = _old_gen->allocate(size, is_tlab);
283 }
284
285 return res;
286 }
287
288 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
289 bool* gc_overhead_limit_was_exceeded) {
290 return collector_policy()->mem_allocate_work(size,
291 false /* is_tlab */,
292 gc_overhead_limit_was_exceeded);
293 }
294
295 bool GenCollectedHeap::must_clear_all_soft_refs() {
296 return _gc_cause == GCCause::_last_ditch_collection;
297 }
298
299 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
300 return UseConcMarkSweepGC &&
301 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
302 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
303 }
304
305 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
306 bool is_tlab, bool run_verification, bool clear_soft_refs,
307 bool restore_marks_for_biased_locking) {
308 // Timer for individual generations. Last argument is false: no CR
309 // FIXME: We should try to start the timing earlier to cover more of the GC pause
310 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
311 // so we can assume here that the next GC id is what we want.
312 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL, GCId::peek());
313 TraceCollectorStats tcs(gen->counters());
314 TraceMemoryManagerStats tmms(gen->kind(),gc_cause());
315
316 size_t prev_used = gen->used();
317 gen->stat_record()->invocations++;
318 gen->stat_record()->accumulated_time.start();
319
320 // Must be done anew before each collection because
321 // a previous collection will do mangling and will
322 // change top of some spaces.
323 record_gen_tops_before_GC();
324
325 if (PrintGC && Verbose) {
326 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
327 gen->level(),
328 gen->stat_record()->invocations,
329 size * HeapWordSize);
330 }
331
332 if (run_verification && VerifyBeforeGC) {
333 HandleMark hm; // Discard invalid handles created during verification
334 Universe::verify(" VerifyBeforeGC:");
335 }
336 COMPILER2_PRESENT(DerivedPointerTable::clear());
337
338 if (restore_marks_for_biased_locking) {
339 // We perform this mark word preservation work lazily
340 // because it's only at this point that we know whether we
341 // absolutely have to do it; we want to avoid doing it for
342 // scavenge-only collections where it's unnecessary
343 BiasedLocking::preserve_marks();
344 }
345
346 // Do collection work
347 {
348 // Note on ref discovery: For what appear to be historical reasons,
349 // GCH enables and disabled (by enqueing) refs discovery.
350 // In the future this should be moved into the generation's
351 // collect method so that ref discovery and enqueueing concerns
352 // are local to a generation. The collect method could return
353 // an appropriate indication in the case that notification on
354 // the ref lock was needed. This will make the treatment of
355 // weak refs more uniform (and indeed remove such concerns
356 // from GCH). XXX
357
358 HandleMark hm; // Discard invalid handles created during gc
359 save_marks(); // save marks for all gens
360 // We want to discover references, but not process them yet.
361 // This mode is disabled in process_discovered_references if the
362 // generation does some collection work, or in
363 // enqueue_discovered_references if the generation returns
364 // without doing any work.
365 ReferenceProcessor* rp = gen->ref_processor();
366 // If the discovery of ("weak") refs in this generation is
367 // atomic wrt other collectors in this configuration, we
368 // are guaranteed to have empty discovered ref lists.
369 if (rp->discovery_is_atomic()) {
370 rp->enable_discovery();
371 rp->setup_policy(clear_soft_refs);
372 } else {
373 // collect() below will enable discovery as appropriate
374 }
375 gen->collect(full, clear_soft_refs, size, is_tlab);
376 if (!rp->enqueuing_is_done()) {
377 rp->enqueue_discovered_references();
378 } else {
379 rp->set_enqueuing_is_done(false);
380 }
381 rp->verify_no_references_recorded();
382 }
383
384 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
385
386 gen->stat_record()->accumulated_time.stop();
387
388 update_gc_stats(gen->level(), full);
389
390 if (run_verification && VerifyAfterGC) {
391 HandleMark hm; // Discard invalid handles created during verification
392 Universe::verify(" VerifyAfterGC:");
393 }
394
395 if (PrintGCDetails) {
396 gclog_or_tty->print(":");
397 gen->print_heap_change(prev_used);
398 }
399 }
400
401 void GenCollectedHeap::do_collection(bool full,
402 bool clear_all_soft_refs,
403 size_t size,
404 bool is_tlab,
405 int max_level) {
406 ResourceMark rm;
407 DEBUG_ONLY(Thread* my_thread = Thread::current();)
408
409 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
410 assert(my_thread->is_VM_thread() ||
411 my_thread->is_ConcurrentGC_thread(),
412 "incorrect thread type capability");
413 assert(Heap_lock->is_locked(),
414 "the requesting thread should have the Heap_lock");
415 guarantee(!is_gc_active(), "collection is not reentrant");
416
417 if (GC_locker::check_active_before_gc()) {
418 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
419 }
420
421 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
422 collector_policy()->should_clear_all_soft_refs();
423
424 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
425
426 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
427
428 print_heap_before_gc();
429
430 {
431 FlagSetting fl(_is_gc_active, true);
432
433 bool complete = full && (max_level == 1 /* old */);
434 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
435 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
436 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
437 // so we can assume here that the next GC id is what we want.
438 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
439
440 gc_prologue(complete);
441 increment_total_collections(complete);
442
443 size_t gch_prev_used = used();
444 bool run_verification = total_collections() >= VerifyGCStartAt;
445
446 bool prepared_for_verification = false;
447 int max_level_collected = 0;
448 bool old_collects_young = (max_level == 1) &&
449 full &&
450 _old_gen->full_collects_younger_generations();
451 if (!old_collects_young &&
452 _young_gen->should_collect(full, size, is_tlab)) {
453 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
454 prepare_for_verify();
455 prepared_for_verification = true;
456 }
457
458 assert(!_young_gen->performs_in_place_marking(), "No young generation do in place marking");
459 collect_generation(_young_gen,
460 full,
461 size,
462 is_tlab,
463 run_verification && VerifyGCLevel <= 0,
464 do_clear_all_soft_refs,
465 false);
466
467 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
468 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
469 // Allocation request was met by young GC.
470 size = 0;
471 }
472 }
473
474 bool must_restore_marks_for_biased_locking = false;
475
476 if (max_level == 1 && _old_gen->should_collect(full, size, is_tlab)) {
477 if (!complete) {
478 // The full_collections increment was missed above.
479 increment_total_full_collections();
480 }
481
482 pre_full_gc_dump(NULL); // do any pre full gc dumps
483
484 if (!prepared_for_verification && run_verification &&
485 VerifyGCLevel <= 1 && VerifyBeforeGC) {
486 prepare_for_verify();
487 }
488
489 assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking");
490 collect_generation(_old_gen,
491 full,
492 size,
493 is_tlab,
494 run_verification && VerifyGCLevel <= 1,
495 do_clear_all_soft_refs,
496 true);
497
498 must_restore_marks_for_biased_locking = true;
499 max_level_collected = 1;
500 }
501
502 // Update "complete" boolean wrt what actually transpired --
503 // for instance, a promotion failure could have led to
504 // a whole heap collection.
505 complete = complete || (max_level_collected == 1 /* old */);
506
507 if (complete) { // We did a "major" collection
508 // FIXME: See comment at pre_full_gc_dump call
509 post_full_gc_dump(NULL); // do any post full gc dumps
510 }
511
512 if (PrintGCDetails) {
513 print_heap_change(gch_prev_used);
514
515 // Print metaspace info for full GC with PrintGCDetails flag.
516 if (complete) {
517 MetaspaceAux::print_metaspace_change(metadata_prev_used);
518 }
519 }
520
521 // Adjust generation sizes.
522 if (max_level_collected == 1 /* old */) {
523 _old_gen->compute_new_size();
524 }
525 _young_gen->compute_new_size();
526
527 if (complete) {
528 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
529 ClassLoaderDataGraph::purge();
530 MetaspaceAux::verify_metrics();
531 // Resize the metaspace capacity after full collections
532 MetaspaceGC::compute_new_size();
533 update_full_collections_completed();
534 }
535
536 // Track memory usage and detect low memory after GC finishes
537 MemoryService::track_memory_usage();
538
539 gc_epilogue(complete);
540
541 if (must_restore_marks_for_biased_locking) {
542 BiasedLocking::restore_marks();
543 }
544 }
545
546 print_heap_after_gc();
547
548 #ifdef TRACESPINNING
549 ParallelTaskTerminator::print_termination_counts();
550 #endif
551 }
552
553 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
554 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
555 }
556
557 void GenCollectedHeap::set_par_threads(uint t) {
558 SharedHeap::set_par_threads(t);
559 set_n_termination(t);
560 }
561
562 void GenCollectedHeap::set_n_termination(uint t) {
563 _process_strong_tasks->set_n_threads(t);
564 }
565
566 #ifdef ASSERT
567 class AssertNonScavengableClosure: public OopClosure {
568 public:
569 virtual void do_oop(oop* p) {
570 assert(!Universe::heap()->is_in_partial_collection(*p),
571 "Referent should not be scavengable."); }
572 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
573 };
574 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
575 #endif
576
577 void GenCollectedHeap::process_roots(bool activate_scope,
578 ScanningOption so,
579 OopClosure* strong_roots,
580 OopClosure* weak_roots,
581 CLDClosure* strong_cld_closure,
582 CLDClosure* weak_cld_closure,
583 CodeBlobClosure* code_roots) {
584 StrongRootsScope srs(this, activate_scope);
585
586 // General roots.
587 assert(_strong_roots_parity != 0, "must have called prologue code");
588 assert(code_roots != NULL, "code root closure should always be set");
589 // _n_termination for _process_strong_tasks should be set up stream
590 // in a method not running in a GC worker. Otherwise the GC worker
591 // could be trying to change the termination condition while the task
592 // is executing in another GC worker.
593
594 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
595 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
596 }
597
598 // Some CLDs contained in the thread frames should be considered strong.
599 // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
600 CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
601 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
602 CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
603
604 Threads::possibly_parallel_oops_do(strong_roots, roots_from_clds_p, roots_from_code_p);
605
606 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
607 Universe::oops_do(strong_roots);
608 }
609 // Global (strong) JNI handles
610 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
611 JNIHandles::oops_do(strong_roots);
612 }
613
614 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
615 ObjectSynchronizer::oops_do(strong_roots);
616 }
617 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
618 FlatProfiler::oops_do(strong_roots);
619 }
620 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
621 Management::oops_do(strong_roots);
622 }
623 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
624 JvmtiExport::oops_do(strong_roots);
625 }
626
627 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
628 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
629 }
630
631 // All threads execute the following. A specific chunk of buckets
632 // from the StringTable are the individual tasks.
633 if (weak_roots != NULL) {
634 if (CollectedHeap::use_parallel_gc_threads()) {
635 StringTable::possibly_parallel_oops_do(weak_roots);
636 } else {
637 StringTable::oops_do(weak_roots);
638 }
639 }
640
641 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
642 if (so & SO_ScavengeCodeCache) {
643 assert(code_roots != NULL, "must supply closure for code cache");
644
645 // We only visit parts of the CodeCache when scavenging.
646 CodeCache::scavenge_root_nmethods_do(code_roots);
647 }
648 if (so & SO_AllCodeCache) {
649 assert(code_roots != NULL, "must supply closure for code cache");
650
651 // CMSCollector uses this to do intermediate-strength collections.
652 // We scan the entire code cache, since CodeCache::do_unloading is not called.
653 CodeCache::blobs_do(code_roots);
654 }
655 // Verify that the code cache contents are not subject to
656 // movement by a scavenging collection.
657 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
658 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
659 }
660
661 }
662
663 void GenCollectedHeap::gen_process_roots(int level,
664 bool younger_gens_as_roots,
665 bool activate_scope,
666 ScanningOption so,
667 bool only_strong_roots,
668 OopsInGenClosure* not_older_gens,
669 OopsInGenClosure* older_gens,
670 CLDClosure* cld_closure) {
671 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
672
673 bool is_moving_collection = false;
674 if (level == 0 || is_adjust_phase) {
675 // young collections are always moving
676 is_moving_collection = true;
677 }
678
679 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
680 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : not_older_gens;
681 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
682
683 process_roots(activate_scope, so,
684 not_older_gens, weak_roots,
685 cld_closure, weak_cld_closure,
686 &mark_code_closure);
687
688 if (younger_gens_as_roots) {
689 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
690 if (level == 1) {
691 not_older_gens->set_generation(_young_gen);
692 _young_gen->oop_iterate(not_older_gens);
693 }
694 not_older_gens->reset_generation();
695 }
696 }
697 // When collection is parallel, all threads get to cooperate to do
698 // older-gen scanning.
699 if (level == 0) {
700 older_gens->set_generation(_old_gen);
701 rem_set()->younger_refs_iterate(_old_gen, older_gens);
702 older_gens->reset_generation();
703 }
704
705 _process_strong_tasks->all_tasks_completed();
706 }
707
708
709 class AlwaysTrueClosure: public BoolObjectClosure {
710 public:
711 bool do_object_b(oop p) { return true; }
712 };
713 static AlwaysTrueClosure always_true;
714
715 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
716 JNIHandles::weak_oops_do(&always_true, root_closure);
717 _young_gen->ref_processor()->weak_oops_do(root_closure);
718 _old_gen->ref_processor()->weak_oops_do(root_closure);
719 }
720
721 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
722 void GenCollectedHeap:: \
723 oop_since_save_marks_iterate(int level, \
724 OopClosureType* cur, \
725 OopClosureType* older) { \
726 if (level == 0) { \
727 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
728 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
729 } else { \
730 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
731 } \
732 }
733
734 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
735
736 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
737
738 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
739 if (level == 0 && !_young_gen->no_allocs_since_save_marks()) {
740 return false;
741 }
742 return _old_gen->no_allocs_since_save_marks();
743 }
744
745 bool GenCollectedHeap::supports_inline_contig_alloc() const {
746 return _young_gen->supports_inline_contig_alloc();
747 }
748
749 HeapWord** GenCollectedHeap::top_addr() const {
750 return _young_gen->top_addr();
751 }
752
753 HeapWord** GenCollectedHeap::end_addr() const {
754 return _young_gen->end_addr();
755 }
756
757 // public collection interfaces
758
759 void GenCollectedHeap::collect(GCCause::Cause cause) {
760 if (should_do_concurrent_full_gc(cause)) {
761 #if INCLUDE_ALL_GCS
762 // mostly concurrent full collection
763 collect_mostly_concurrent(cause);
764 #else // INCLUDE_ALL_GCS
765 ShouldNotReachHere();
766 #endif // INCLUDE_ALL_GCS
767 } else if (cause == GCCause::_wb_young_gc) {
768 // minor collection for WhiteBox API
769 collect(cause, 0 /* young */);
770 } else {
771 #ifdef ASSERT
772 if (cause == GCCause::_scavenge_alot) {
773 // minor collection only
774 collect(cause, 0 /* young */);
775 } else {
776 // Stop-the-world full collection
777 collect(cause, 1 /* old */);
778 }
779 #else
780 // Stop-the-world full collection
781 collect(cause, 1 /* old */);
782 #endif
783 }
784 }
785
786 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
787 // The caller doesn't have the Heap_lock
788 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
789 MutexLocker ml(Heap_lock);
790 collect_locked(cause, max_level);
791 }
792
793 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
794 // The caller has the Heap_lock
795 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
796 collect_locked(cause, 1 /* old */);
797 }
798
799 // this is the private collection interface
800 // The Heap_lock is expected to be held on entry.
801
802 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
803 // Read the GC count while holding the Heap_lock
804 unsigned int gc_count_before = total_collections();
805 unsigned int full_gc_count_before = total_full_collections();
806 {
807 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
808 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
809 cause, max_level);
810 VMThread::execute(&op);
811 }
812 }
813
814 #if INCLUDE_ALL_GCS
815 bool GenCollectedHeap::create_cms_collector() {
816
817 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep,
818 "Unexpected generation kinds");
819 // Skip two header words in the block content verification
820 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
821 CMSCollector* collector = new CMSCollector(
822 (ConcurrentMarkSweepGeneration*)_old_gen,
823 _rem_set->as_CardTableRS(),
824 (ConcurrentMarkSweepPolicy*) collector_policy());
825
826 if (collector == NULL || !collector->completed_initialization()) {
827 if (collector) {
828 delete collector; // Be nice in embedded situation
829 }
830 vm_shutdown_during_initialization("Could not create CMS collector");
831 return false;
832 }
833 return true; // success
834 }
835
836 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
837 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
838
839 MutexLocker ml(Heap_lock);
840 // Read the GC counts while holding the Heap_lock
841 unsigned int full_gc_count_before = total_full_collections();
842 unsigned int gc_count_before = total_collections();
843 {
844 MutexUnlocker mu(Heap_lock);
845 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
846 VMThread::execute(&op);
847 }
848 }
849 #endif // INCLUDE_ALL_GCS
850
851 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
852 do_full_collection(clear_all_soft_refs, 1 /* old */);
853 }
854
855 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
856 int max_level) {
857 int local_max_level;
858 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
859 gc_cause() == GCCause::_gc_locker) {
860 local_max_level = 0;
861 } else {
862 local_max_level = max_level;
863 }
864
865 do_collection(true /* full */,
866 clear_all_soft_refs /* clear_all_soft_refs */,
867 0 /* size */,
868 false /* is_tlab */,
869 local_max_level /* max_level */);
870 // Hack XXX FIX ME !!!
871 // A scavenge may not have been attempted, or may have
872 // been attempted and failed, because the old gen was too full
873 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
874 incremental_collection_will_fail(false /* don't consult_young */)) {
875 if (PrintGCDetails) {
876 gclog_or_tty->print_cr("GC locker: Trying a full collection "
877 "because scavenge failed");
878 }
879 // This time allow the old gen to be collected as well
880 do_collection(true /* full */,
881 clear_all_soft_refs /* clear_all_soft_refs */,
882 0 /* size */,
883 false /* is_tlab */,
884 1 /* old */ /* max_level */);
885 }
886 }
887
888 bool GenCollectedHeap::is_in_young(oop p) {
889 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
890 assert(result == _young_gen->is_in_reserved(p),
891 err_msg("incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)));
892 return result;
893 }
894
895 // Returns "TRUE" iff "p" points into the committed areas of the heap.
896 bool GenCollectedHeap::is_in(const void* p) const {
897 #ifndef ASSERT
898 guarantee(VerifyBeforeGC ||
899 VerifyDuringGC ||
900 VerifyBeforeExit ||
901 VerifyDuringStartup ||
902 PrintAssembly ||
903 tty->count() != 0 || // already printing
904 VerifyAfterGC ||
905 VMError::fatal_error_in_progress(), "too expensive");
906
907 #endif
908 return _young_gen->is_in(p) || _old_gen->is_in(p);
909 }
910
911 #ifdef ASSERT
912 // Don't implement this by using is_in_young(). This method is used
913 // in some cases to check that is_in_young() is correct.
914 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
915 assert(is_in_reserved(p) || p == NULL,
916 "Does not work if address is non-null and outside of the heap");
917 return p < _young_gen->reserved().end() && p != NULL;
918 }
919 #endif
920
921 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
922 _young_gen->oop_iterate(cl);
923 _old_gen->oop_iterate(cl);
924 }
925
926 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
927 _young_gen->object_iterate(cl);
928 _old_gen->object_iterate(cl);
929 }
930
931 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
932 _young_gen->safe_object_iterate(cl);
933 _old_gen->safe_object_iterate(cl);
934 }
935
936 Space* GenCollectedHeap::space_containing(const void* addr) const {
937 Space* res = _young_gen->space_containing(addr);
938 if (res != NULL) {
939 return res;
940 }
941 res = _old_gen->space_containing(addr);
942 assert(res != NULL, "Could not find containing space");
943 return res;
944 }
945
946 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
947 assert(is_in_reserved(addr), "block_start of address outside of heap");
948 if (_young_gen->is_in_reserved(addr)) {
949 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
950 return _young_gen->block_start(addr);
951 }
952
953 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
954 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
955 return _old_gen->block_start(addr);
956 }
957
958 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
959 assert(is_in_reserved(addr), "block_size of address outside of heap");
960 if (_young_gen->is_in_reserved(addr)) {
961 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
962 return _young_gen->block_size(addr);
963 }
964
965 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
966 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
967 return _old_gen->block_size(addr);
968 }
969
970 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
971 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
972 assert(block_start(addr) == addr, "addr must be a block start");
973 if (_young_gen->is_in_reserved(addr)) {
974 return _young_gen->block_is_obj(addr);
975 }
976
977 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
978 return _old_gen->block_is_obj(addr);
979 }
980
981 bool GenCollectedHeap::supports_tlab_allocation() const {
982 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
983 return _young_gen->supports_tlab_allocation();
984 }
985
986 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
987 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
988 if (_young_gen->supports_tlab_allocation()) {
989 return _young_gen->tlab_capacity();
990 }
991 return 0;
992 }
993
994 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
995 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
996 if (_young_gen->supports_tlab_allocation()) {
997 return _young_gen->tlab_used();
998 }
999 return 0;
1000 }
1001
1002 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1003 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1004 if (_young_gen->supports_tlab_allocation()) {
1005 return _young_gen->unsafe_max_tlab_alloc();
1006 }
1007 return 0;
1008 }
1009
1010 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1011 bool gc_overhead_limit_was_exceeded;
1012 return collector_policy()->mem_allocate_work(size /* size */,
1013 true /* is_tlab */,
1014 &gc_overhead_limit_was_exceeded);
1015 }
1016
1017 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1018 // from the list headed by "*prev_ptr".
1019 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1020 bool first = true;
1021 size_t min_size = 0; // "first" makes this conceptually infinite.
1022 ScratchBlock **smallest_ptr, *smallest;
1023 ScratchBlock *cur = *prev_ptr;
1024 while (cur) {
1025 assert(*prev_ptr == cur, "just checking");
1026 if (first || cur->num_words < min_size) {
1027 smallest_ptr = prev_ptr;
1028 smallest = cur;
1029 min_size = smallest->num_words;
1030 first = false;
1031 }
1032 prev_ptr = &cur->next;
1033 cur = cur->next;
1034 }
1035 smallest = *smallest_ptr;
1036 *smallest_ptr = smallest->next;
1037 return smallest;
1038 }
1039
1040 // Sort the scratch block list headed by res into decreasing size order,
1041 // and set "res" to the result.
1042 static void sort_scratch_list(ScratchBlock*& list) {
1043 ScratchBlock* sorted = NULL;
1044 ScratchBlock* unsorted = list;
1045 while (unsorted) {
1046 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1047 smallest->next = sorted;
1048 sorted = smallest;
1049 }
1050 list = sorted;
1051 }
1052
1053 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1054 size_t max_alloc_words) {
1055 ScratchBlock* res = NULL;
1056 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1057 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1058 sort_scratch_list(res);
1059 return res;
1060 }
1061
1062 void GenCollectedHeap::release_scratch() {
1063 _young_gen->reset_scratch();
1064 _old_gen->reset_scratch();
1065 }
1066
1067 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1068 void do_generation(Generation* gen) {
1069 gen->prepare_for_verify();
1070 }
1071 };
1072
1073 void GenCollectedHeap::prepare_for_verify() {
1074 ensure_parsability(false); // no need to retire TLABs
1075 GenPrepareForVerifyClosure blk;
1076 generation_iterate(&blk, false);
1077 }
1078
1079 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1080 bool old_to_young) {
1081 if (old_to_young) {
1082 cl->do_generation(_old_gen);
1083 cl->do_generation(_young_gen);
1084 } else {
1085 cl->do_generation(_young_gen);
1086 cl->do_generation(_old_gen);
1087 }
1088 }
1089
1090 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1091 _young_gen->space_iterate(cl, true);
1092 _old_gen->space_iterate(cl, true);
1093 }
1094
1095 bool GenCollectedHeap::is_maximal_no_gc() const {
1096 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1097 }
1098
1099 void GenCollectedHeap::save_marks() {
1100 _young_gen->save_marks();
1101 _old_gen->save_marks();
1102 }
1103
1104 GenCollectedHeap* GenCollectedHeap::heap() {
1105 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1106 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1107 return _gch;
1108 }
1109
1110 void GenCollectedHeap::prepare_for_compaction() {
1111 // Start by compacting into same gen.
1112 CompactPoint cp(_old_gen);
1113 _old_gen->prepare_for_compaction(&cp);
1114 _young_gen->prepare_for_compaction(&cp);
1115 }
1116
1117 GCStats* GenCollectedHeap::gc_stats(int level) const {
1118 if (level == 0) {
1119 return _young_gen->gc_stats();
1120 } else {
1121 return _old_gen->gc_stats();
1122 }
1123 }
1124
1125 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1126 if (!silent) {
1127 gclog_or_tty->print("%s", _old_gen->name());
1128 gclog_or_tty->print(" ");
1129 }
1130 _old_gen->verify();
1131
1132 if (!silent) {
1133 gclog_or_tty->print("%s", _young_gen->name());
1134 gclog_or_tty->print(" ");
1135 }
1136 _young_gen->verify();
1137
1138 if (!silent) {
1139 gclog_or_tty->print("remset ");
1140 }
1141 rem_set()->verify();
1142 }
1143
1144 void GenCollectedHeap::print_on(outputStream* st) const {
1145 _young_gen->print_on(st);
1146 _old_gen->print_on(st);
1147 MetaspaceAux::print_on(st);
1148 }
1149
1150 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1151 if (workers() != NULL) {
1152 workers()->threads_do(tc);
1153 }
1154 #if INCLUDE_ALL_GCS
1155 if (UseConcMarkSweepGC) {
1156 ConcurrentMarkSweepThread::threads_do(tc);
1157 }
1158 #endif // INCLUDE_ALL_GCS
1159 }
1160
1161 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1162 #if INCLUDE_ALL_GCS
1163 if (UseConcMarkSweepGC) {
1164 workers()->print_worker_threads_on(st);
1165 ConcurrentMarkSweepThread::print_all_on(st);
1166 }
1167 #endif // INCLUDE_ALL_GCS
1168 }
1169
1170 void GenCollectedHeap::print_on_error(outputStream* st) const {
1171 this->CollectedHeap::print_on_error(st);
1172
1173 #if INCLUDE_ALL_GCS
1174 if (UseConcMarkSweepGC) {
1175 st->cr();
1176 CMSCollector::print_on_error(st);
1177 }
1178 #endif // INCLUDE_ALL_GCS
1179 }
1180
1181 void GenCollectedHeap::print_tracing_info() const {
1182 if (TraceYoungGenTime) {
1183 _young_gen->print_summary_info();
1184 }
1185 if (TraceOldGenTime) {
1186 _old_gen->print_summary_info();
1187 }
1188 }
1189
1190 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1191 if (PrintGCDetails && Verbose) {
1192 gclog_or_tty->print(" " SIZE_FORMAT
1193 "->" SIZE_FORMAT
1194 "(" SIZE_FORMAT ")",
1195 prev_used, used(), capacity());
1196 } else {
1197 gclog_or_tty->print(" " SIZE_FORMAT "K"
1198 "->" SIZE_FORMAT "K"
1199 "(" SIZE_FORMAT "K)",
1200 prev_used / K, used() / K, capacity() / K);
1201 }
1202 }
1203
1204 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1205 private:
1206 bool _full;
1207 public:
1208 void do_generation(Generation* gen) {
1209 gen->gc_prologue(_full);
1210 }
1211 GenGCPrologueClosure(bool full) : _full(full) {};
1212 };
1213
1214 void GenCollectedHeap::gc_prologue(bool full) {
1215 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1216
1217 always_do_update_barrier = false;
1218 // Fill TLAB's and such
1219 CollectedHeap::accumulate_statistics_all_tlabs();
1220 ensure_parsability(true); // retire TLABs
1221
1222 // Walk generations
1223 GenGCPrologueClosure blk(full);
1224 generation_iterate(&blk, false); // not old-to-young.
1225 };
1226
1227 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1228 private:
1229 bool _full;
1230 public:
1231 void do_generation(Generation* gen) {
1232 gen->gc_epilogue(_full);
1233 }
1234 GenGCEpilogueClosure(bool full) : _full(full) {};
1235 };
1236
1237 void GenCollectedHeap::gc_epilogue(bool full) {
1238 #ifdef COMPILER2
1239 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1240 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1241 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1242 #endif /* COMPILER2 */
1243
1244 resize_all_tlabs();
1245
1246 GenGCEpilogueClosure blk(full);
1247 generation_iterate(&blk, false); // not old-to-young.
1248
1249 if (!CleanChunkPoolAsync) {
1250 Chunk::clean_chunk_pool();
1251 }
1252
1253 MetaspaceCounters::update_performance_counters();
1254 CompressedClassSpaceCounters::update_performance_counters();
1255
1256 always_do_update_barrier = UseConcMarkSweepGC;
1257 };
1258
1259 #ifndef PRODUCT
1260 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1261 private:
1262 public:
1263 void do_generation(Generation* gen) {
1264 gen->record_spaces_top();
1265 }
1266 };
1267
1268 void GenCollectedHeap::record_gen_tops_before_GC() {
1269 if (ZapUnusedHeapArea) {
1270 GenGCSaveTopsBeforeGCClosure blk;
1271 generation_iterate(&blk, false); // not old-to-young.
1272 }
1273 }
1274 #endif // not PRODUCT
1275
1276 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1277 public:
1278 void do_generation(Generation* gen) {
1279 gen->ensure_parsability();
1280 }
1281 };
1282
1283 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1284 CollectedHeap::ensure_parsability(retire_tlabs);
1285 GenEnsureParsabilityClosure ep_cl;
1286 generation_iterate(&ep_cl, false);
1287 }
1288
1289 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1290 oop obj,
1291 size_t obj_size) {
1292 guarantee(old_gen->level() == 1, "We only get here with an old generation");
1293 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1294 HeapWord* result = NULL;
1295
1296 result = old_gen->expand_and_allocate(obj_size, false);
1297
1298 if (result != NULL) {
1299 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1300 }
1301 return oop(result);
1302 }
1303
1304 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1305 jlong _time; // in ms
1306 jlong _now; // in ms
1307
1308 public:
1309 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1310
1311 jlong time() { return _time; }
1312
1313 void do_generation(Generation* gen) {
1314 _time = MIN2(_time, gen->time_of_last_gc(_now));
1315 }
1316 };
1317
1318 jlong GenCollectedHeap::millis_since_last_gc() {
1319 // We need a monotonically non-decreasing time in ms but
1320 // os::javaTimeMillis() does not guarantee monotonicity.
1321 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1322 GenTimeOfLastGCClosure tolgc_cl(now);
1323 // iterate over generations getting the oldest
1324 // time that a generation was collected
1325 generation_iterate(&tolgc_cl, false);
1326
1327 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1328 // provided the underlying platform provides such a time source
1329 // (and it is bug free). So we still have to guard against getting
1330 // back a time later than 'now'.
1331 jlong retVal = now - tolgc_cl.time();
1332 if (retVal < 0) {
1333 NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, retVal);)
1334 return 0;
1335 }
1336 return retVal;
1337 }