1 /*
2 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classLoaderDataGraph.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/stringTable.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "gc/serial/defNewGeneration.hpp"
34 #include "gc/shared/adaptiveSizePolicy.hpp"
35 #include "gc/shared/cardTableBarrierSet.hpp"
36 #include "gc/shared/cardTableRS.hpp"
37 #include "gc/shared/collectedHeap.inline.hpp"
38 #include "gc/shared/collectorCounters.hpp"
39 #include "gc/shared/gcId.hpp"
40 #include "gc/shared/gcLocker.hpp"
41 #include "gc/shared/gcPolicyCounters.hpp"
42 #include "gc/shared/gcTrace.hpp"
43 #include "gc/shared/gcTraceTime.inline.hpp"
44 #include "gc/shared/genArguments.hpp"
45 #include "gc/shared/gcVMOperations.hpp"
46 #include "gc/shared/genCollectedHeap.hpp"
47 #include "gc/shared/genOopClosures.inline.hpp"
48 #include "gc/shared/generationSpec.hpp"
49 #include "gc/shared/gcInitLogger.hpp"
50 #include "gc/shared/locationPrinter.inline.hpp"
51 #include "gc/shared/oopStorage.inline.hpp"
52 #include "gc/shared/oopStorageSet.inline.hpp"
53 #include "gc/shared/oopStorageParState.inline.hpp"
54 #include "gc/shared/scavengableNMethods.hpp"
55 #include "gc/shared/space.hpp"
56 #include "gc/shared/strongRootsScope.hpp"
57 #include "gc/shared/weakProcessor.hpp"
58 #include "gc/shared/workgroup.hpp"
59 #include "memory/filemap.hpp"
60 #include "memory/iterator.hpp"
61 #include "memory/metaspaceCounters.hpp"
62 #include "memory/resourceArea.hpp"
63 #include "memory/universe.hpp"
64 #include "oops/oop.inline.hpp"
65 #include "runtime/biasedLocking.hpp"
66 #include "runtime/handles.hpp"
67 #include "runtime/handles.inline.hpp"
68 #include "runtime/java.hpp"
69 #include "runtime/vmThread.hpp"
70 #include "services/memoryService.hpp"
71 #include "utilities/autoRestore.hpp"
72 #include "utilities/debug.hpp"
73 #include "utilities/formatBuffer.hpp"
74 #include "utilities/macros.hpp"
75 #include "utilities/stack.inline.hpp"
76 #include "utilities/vmError.hpp"
77 #if INCLUDE_JVMCI
78 #include "jvmci/jvmci.hpp"
79 #endif
80
81 GenCollectedHeap::GenCollectedHeap(Generation::Name young,
82 Generation::Name old,
83 const char* policy_counters_name) :
84 CollectedHeap(),
85 _young_gen(NULL),
86 _old_gen(NULL),
87 _young_gen_spec(new GenerationSpec(young,
88 NewSize,
89 MaxNewSize,
90 GenAlignment)),
91 _old_gen_spec(new GenerationSpec(old,
92 OldSize,
93 MaxOldSize,
94 GenAlignment)),
95 _rem_set(NULL),
96 _soft_ref_gen_policy(),
97 _size_policy(NULL),
98 _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)),
99 _incremental_collection_failed(false),
100 _full_collections_completed(0),
101 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
102 _young_manager(NULL),
103 _old_manager(NULL) {
104 }
105
106 jint GenCollectedHeap::initialize() {
107 // While there are no constraints in the GC code that HeapWordSize
108 // be any particular value, there are multiple other areas in the
109 // system which believe this to be true (e.g. oop->object_size in some
110 // cases incorrectly returns the size in wordSize units rather than
111 // HeapWordSize).
112 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
113
114 // Allocate space for the heap.
115
116 ReservedHeapSpace heap_rs = allocate(HeapAlignment);
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(heap_rs);
125
126 _rem_set = create_rem_set(heap_rs.region());
127 _rem_set->initialize();
128 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set);
129 bs->initialize();
130 BarrierSet::set_barrier_set(bs);
131
132 ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size());
133 _young_gen = _young_gen_spec->init(young_rs, rem_set());
134 ReservedSpace old_rs = heap_rs.last_part(_young_gen_spec->max_size());
135
136 old_rs = old_rs.first_part(_old_gen_spec->max_size());
137 _old_gen = _old_gen_spec->init(old_rs, rem_set());
138
139 GCInitLogger::print();
140
141 return JNI_OK;
142 }
143
144 CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) {
145 return new CardTableRS(reserved_region, false /* scan_concurrently */);
146 }
147
148 void GenCollectedHeap::initialize_size_policy(size_t init_eden_size,
149 size_t init_promo_size,
150 size_t init_survivor_size) {
151 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
152 _size_policy = new AdaptiveSizePolicy(init_eden_size,
153 init_promo_size,
154 init_survivor_size,
155 max_gc_pause_sec,
156 GCTimeRatio);
157 }
158
159 ReservedHeapSpace GenCollectedHeap::allocate(size_t alignment) {
160 // Now figure out the total size.
161 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
162 assert(alignment % pageSize == 0, "Must be");
163
164 // Check for overflow.
165 size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size();
166 if (total_reserved < _young_gen_spec->max_size()) {
167 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
168 "the maximum representable size");
169 }
170 assert(total_reserved % alignment == 0,
171 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
172 SIZE_FORMAT, total_reserved, alignment);
173
174 ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment);
175
176 os::trace_page_sizes("Heap",
177 MinHeapSize,
178 total_reserved,
179 alignment,
180 heap_rs.base(),
181 heap_rs.size());
182
183 return heap_rs;
184 }
185
186 class GenIsScavengable : public BoolObjectClosure {
187 public:
188 bool do_object_b(oop obj) {
189 return GenCollectedHeap::heap()->is_in_young(obj);
190 }
191 };
192
193 static GenIsScavengable _is_scavengable;
194
195 void GenCollectedHeap::post_initialize() {
196 CollectedHeap::post_initialize();
197 ref_processing_init();
198
199 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
200
201 initialize_size_policy(def_new_gen->eden()->capacity(),
202 _old_gen->capacity(),
203 def_new_gen->from()->capacity());
204
205 MarkSweep::initialize();
206
207 ScavengableNMethods::initialize(&_is_scavengable);
208 }
209
210 void GenCollectedHeap::ref_processing_init() {
211 _young_gen->ref_processor_init();
212 _old_gen->ref_processor_init();
213 }
214
215 PreGenGCValues GenCollectedHeap::get_pre_gc_values() const {
216 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
217
218 return PreGenGCValues(def_new_gen->used(),
219 def_new_gen->capacity(),
220 def_new_gen->eden()->used(),
221 def_new_gen->eden()->capacity(),
222 def_new_gen->from()->used(),
223 def_new_gen->from()->capacity(),
224 old_gen()->used(),
225 old_gen()->capacity());
226 }
227
228 GenerationSpec* GenCollectedHeap::young_gen_spec() const {
229 return _young_gen_spec;
230 }
231
232 GenerationSpec* GenCollectedHeap::old_gen_spec() const {
233 return _old_gen_spec;
234 }
235
236 size_t GenCollectedHeap::capacity() const {
237 return _young_gen->capacity() + _old_gen->capacity();
238 }
239
240 size_t GenCollectedHeap::used() const {
241 return _young_gen->used() + _old_gen->used();
242 }
243
244 void GenCollectedHeap::save_used_regions() {
245 _old_gen->save_used_region();
246 _young_gen->save_used_region();
247 }
248
249 size_t GenCollectedHeap::max_capacity() const {
250 return _young_gen->max_capacity() + _old_gen->max_capacity();
251 }
252
253 // Update the _full_collections_completed counter
254 // at the end of a stop-world full GC.
255 unsigned int GenCollectedHeap::update_full_collections_completed() {
256 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
257 assert(_full_collections_completed <= _total_full_collections,
258 "Can't complete more collections than were started");
259 _full_collections_completed = _total_full_collections;
260 ml.notify_all();
261 return _full_collections_completed;
262 }
263
264 // Update the _full_collections_completed counter, as appropriate,
265 // at the end of a concurrent GC cycle. Note the conditional update
266 // below to allow this method to be called by a concurrent collector
267 // without synchronizing in any manner with the VM thread (which
268 // may already have initiated a STW full collection "concurrently").
269 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
270 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
271 assert((_full_collections_completed <= _total_full_collections) &&
272 (count <= _total_full_collections),
273 "Can't complete more collections than were started");
274 if (count > _full_collections_completed) {
275 _full_collections_completed = count;
276 ml.notify_all();
277 }
278 return _full_collections_completed;
279 }
280
281 // Return true if any of the following is true:
282 // . the allocation won't fit into the current young gen heap
283 // . gc locker is occupied (jni critical section)
284 // . heap memory is tight -- the most recent previous collection
285 // was a full collection because a partial collection (would
286 // have) failed and is likely to fail again
287 bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const {
288 size_t young_capacity = _young_gen->capacity_before_gc();
289 return (word_size > heap_word_size(young_capacity))
290 || GCLocker::is_active_and_needs_gc()
291 || incremental_collection_failed();
292 }
293
294 HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) {
295 HeapWord* result = NULL;
296 if (_old_gen->should_allocate(size, is_tlab)) {
297 result = _old_gen->expand_and_allocate(size, is_tlab);
298 }
299 if (result == NULL) {
300 if (_young_gen->should_allocate(size, is_tlab)) {
301 result = _young_gen->expand_and_allocate(size, is_tlab);
302 }
303 }
304 assert(result == NULL || is_in_reserved(result), "result not in heap");
305 return result;
306 }
307
308 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size,
309 bool is_tlab,
310 bool* gc_overhead_limit_was_exceeded) {
311 // In general gc_overhead_limit_was_exceeded should be false so
312 // set it so here and reset it to true only if the gc time
313 // limit is being exceeded as checked below.
314 *gc_overhead_limit_was_exceeded = false;
315
316 HeapWord* result = NULL;
317
318 // Loop until the allocation is satisfied, or unsatisfied after GC.
319 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
320 HandleMark hm; // Discard any handles allocated in each iteration.
321
322 // First allocation attempt is lock-free.
323 Generation *young = _young_gen;
324 assert(young->supports_inline_contig_alloc(),
325 "Otherwise, must do alloc within heap lock");
326 if (young->should_allocate(size, is_tlab)) {
327 result = young->par_allocate(size, is_tlab);
328 if (result != NULL) {
329 assert(is_in_reserved(result), "result not in heap");
330 return result;
331 }
332 }
333 uint gc_count_before; // Read inside the Heap_lock locked region.
334 {
335 MutexLocker ml(Heap_lock);
336 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation");
337 // Note that only large objects get a shot at being
338 // allocated in later generations.
339 bool first_only = !should_try_older_generation_allocation(size);
340
341 result = attempt_allocation(size, is_tlab, first_only);
342 if (result != NULL) {
343 assert(is_in_reserved(result), "result not in heap");
344 return result;
345 }
346
347 if (GCLocker::is_active_and_needs_gc()) {
348 if (is_tlab) {
349 return NULL; // Caller will retry allocating individual object.
350 }
351 if (!is_maximal_no_gc()) {
352 // Try and expand heap to satisfy request.
353 result = expand_heap_and_allocate(size, is_tlab);
354 // Result could be null if we are out of space.
355 if (result != NULL) {
356 return result;
357 }
358 }
359
360 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
361 return NULL; // We didn't get to do a GC and we didn't get any memory.
362 }
363
364 // If this thread is not in a jni critical section, we stall
365 // the requestor until the critical section has cleared and
366 // GC allowed. When the critical section clears, a GC is
367 // initiated by the last thread exiting the critical section; so
368 // we retry the allocation sequence from the beginning of the loop,
369 // rather than causing more, now probably unnecessary, GC attempts.
370 JavaThread* jthr = JavaThread::current();
371 if (!jthr->in_critical()) {
372 MutexUnlocker mul(Heap_lock);
373 // Wait for JNI critical section to be exited
374 GCLocker::stall_until_clear();
375 gclocker_stalled_count += 1;
376 continue;
377 } else {
378 if (CheckJNICalls) {
379 fatal("Possible deadlock due to allocating while"
380 " in jni critical section");
381 }
382 return NULL;
383 }
384 }
385
386 // Read the gc count while the heap lock is held.
387 gc_count_before = total_collections();
388 }
389
390 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
391 VMThread::execute(&op);
392 if (op.prologue_succeeded()) {
393 result = op.result();
394 if (op.gc_locked()) {
395 assert(result == NULL, "must be NULL if gc_locked() is true");
396 continue; // Retry and/or stall as necessary.
397 }
398
399 // Allocation has failed and a collection
400 // has been done. If the gc time limit was exceeded the
401 // this time, return NULL so that an out-of-memory
402 // will be thrown. Clear gc_overhead_limit_exceeded
403 // so that the overhead exceeded does not persist.
404
405 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
406 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear();
407
408 if (limit_exceeded && softrefs_clear) {
409 *gc_overhead_limit_was_exceeded = true;
410 size_policy()->set_gc_overhead_limit_exceeded(false);
411 if (op.result() != NULL) {
412 CollectedHeap::fill_with_object(op.result(), size);
413 }
414 return NULL;
415 }
416 assert(result == NULL || is_in_reserved(result),
417 "result not in heap");
418 return result;
419 }
420
421 // Give a warning if we seem to be looping forever.
422 if ((QueuedAllocationWarningCount > 0) &&
423 (try_count % QueuedAllocationWarningCount == 0)) {
424 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times,"
425 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : "");
426 }
427 }
428 }
429
430 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
431 bool is_tlab,
432 bool first_only) {
433 HeapWord* res = NULL;
434
435 if (_young_gen->should_allocate(size, is_tlab)) {
436 res = _young_gen->allocate(size, is_tlab);
437 if (res != NULL || first_only) {
438 return res;
439 }
440 }
441
442 if (_old_gen->should_allocate(size, is_tlab)) {
443 res = _old_gen->allocate(size, is_tlab);
444 }
445
446 return res;
447 }
448
449 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
450 bool* gc_overhead_limit_was_exceeded) {
451 return mem_allocate_work(size,
452 false /* is_tlab */,
453 gc_overhead_limit_was_exceeded);
454 }
455
456 bool GenCollectedHeap::must_clear_all_soft_refs() {
457 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
458 _gc_cause == GCCause::_wb_full_gc;
459 }
460
461 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
462 bool is_tlab, bool run_verification, bool clear_soft_refs,
463 bool restore_marks_for_biased_locking) {
464 FormatBuffer<> title("Collect gen: %s", gen->short_name());
465 GCTraceTime(Trace, gc, phases) t1(title);
466 TraceCollectorStats tcs(gen->counters());
467 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause());
468
469 gen->stat_record()->invocations++;
470 gen->stat_record()->accumulated_time.start();
471
472 // Must be done anew before each collection because
473 // a previous collection will do mangling and will
474 // change top of some spaces.
475 record_gen_tops_before_GC();
476
477 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
478
479 if (run_verification && VerifyBeforeGC) {
480 HandleMark hm; // Discard invalid handles created during verification
481 Universe::verify("Before GC");
482 }
483 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear());
484
485 if (restore_marks_for_biased_locking) {
486 // We perform this mark word preservation work lazily
487 // because it's only at this point that we know whether we
488 // absolutely have to do it; we want to avoid doing it for
489 // scavenge-only collections where it's unnecessary
490 BiasedLocking::preserve_marks();
491 }
492
493 // Do collection work
494 {
495 // Note on ref discovery: For what appear to be historical reasons,
496 // GCH enables and disabled (by enqueing) refs discovery.
497 // In the future this should be moved into the generation's
498 // collect method so that ref discovery and enqueueing concerns
499 // are local to a generation. The collect method could return
500 // an appropriate indication in the case that notification on
501 // the ref lock was needed. This will make the treatment of
502 // weak refs more uniform (and indeed remove such concerns
503 // from GCH). XXX
504
505 HandleMark hm; // Discard invalid handles created during gc
506 save_marks(); // save marks for all gens
507 // We want to discover references, but not process them yet.
508 // This mode is disabled in process_discovered_references if the
509 // generation does some collection work, or in
510 // enqueue_discovered_references if the generation returns
511 // without doing any work.
512 ReferenceProcessor* rp = gen->ref_processor();
513 // If the discovery of ("weak") refs in this generation is
514 // atomic wrt other collectors in this configuration, we
515 // are guaranteed to have empty discovered ref lists.
516 if (rp->discovery_is_atomic()) {
517 rp->enable_discovery();
518 rp->setup_policy(clear_soft_refs);
519 } else {
520 // collect() below will enable discovery as appropriate
521 }
522 gen->collect(full, clear_soft_refs, size, is_tlab);
523 if (!rp->enqueuing_is_done()) {
524 rp->disable_discovery();
525 } else {
526 rp->set_enqueuing_is_done(false);
527 }
528 rp->verify_no_references_recorded();
529 }
530
531 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers());
532
533 gen->stat_record()->accumulated_time.stop();
534
535 update_gc_stats(gen, full);
536
537 if (run_verification && VerifyAfterGC) {
538 HandleMark hm; // Discard invalid handles created during verification
539 Universe::verify("After GC");
540 }
541 }
542
543 void GenCollectedHeap::do_collection(bool full,
544 bool clear_all_soft_refs,
545 size_t size,
546 bool is_tlab,
547 GenerationType max_generation) {
548 ResourceMark rm;
549 DEBUG_ONLY(Thread* my_thread = Thread::current();)
550
551 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
552 assert(my_thread->is_VM_thread() ||
553 my_thread->is_ConcurrentGC_thread(),
554 "incorrect thread type capability");
555 assert(Heap_lock->is_locked(),
556 "the requesting thread should have the Heap_lock");
557 guarantee(!is_gc_active(), "collection is not reentrant");
558
559 if (GCLocker::check_active_before_gc()) {
560 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
561 }
562
563 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
564 soft_ref_policy()->should_clear_all_soft_refs();
565
566 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy());
567
568 AutoModifyRestore<bool> temporarily(_is_gc_active, true);
569
570 bool complete = full && (max_generation == OldGen);
571 bool old_collects_young = complete && !ScavengeBeforeFullGC;
572 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
573
574 const PreGenGCValues pre_gc_values = get_pre_gc_values();
575
576 bool run_verification = total_collections() >= VerifyGCStartAt;
577 bool prepared_for_verification = false;
578 bool do_full_collection = false;
579
580 if (do_young_collection) {
581 GCIdMark gc_id_mark;
582 GCTraceCPUTime tcpu;
583 GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true);
584
585 print_heap_before_gc();
586
587 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
588 prepare_for_verify();
589 prepared_for_verification = true;
590 }
591
592 gc_prologue(complete);
593 increment_total_collections(complete);
594
595 collect_generation(_young_gen,
596 full,
597 size,
598 is_tlab,
599 run_verification && VerifyGCLevel <= 0,
600 do_clear_all_soft_refs,
601 false);
602
603 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
604 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
605 // Allocation request was met by young GC.
606 size = 0;
607 }
608
609 // Ask if young collection is enough. If so, do the final steps for young collection,
610 // and fallthrough to the end.
611 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
612 if (!do_full_collection) {
613 // Adjust generation sizes.
614 _young_gen->compute_new_size();
615
616 print_heap_change(pre_gc_values);
617
618 // Track memory usage and detect low memory after GC finishes
619 MemoryService::track_memory_usage();
620
621 gc_epilogue(complete);
622 }
623
624 print_heap_after_gc();
625
626 } else {
627 // No young collection, ask if we need to perform Full collection.
628 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
629 }
630
631 if (do_full_collection) {
632 GCIdMark gc_id_mark;
633 GCTraceCPUTime tcpu;
634 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
635
636 print_heap_before_gc();
637
638 if (!prepared_for_verification && run_verification &&
639 VerifyGCLevel <= 1 && VerifyBeforeGC) {
640 prepare_for_verify();
641 }
642
643 if (!do_young_collection) {
644 gc_prologue(complete);
645 increment_total_collections(complete);
646 }
647
648 // Accounting quirk: total full collections would be incremented when "complete"
649 // is set, by calling increment_total_collections above. However, we also need to
650 // account Full collections that had "complete" unset.
651 if (!complete) {
652 increment_total_full_collections();
653 }
654
655 collect_generation(_old_gen,
656 full,
657 size,
658 is_tlab,
659 run_verification && VerifyGCLevel <= 1,
660 do_clear_all_soft_refs,
661 true);
662
663 // Adjust generation sizes.
664 _old_gen->compute_new_size();
665 _young_gen->compute_new_size();
666
667 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
668 ClassLoaderDataGraph::purge();
669 MetaspaceUtils::verify_metrics();
670 // Resize the metaspace capacity after full collections
671 MetaspaceGC::compute_new_size();
672 update_full_collections_completed();
673
674 print_heap_change(pre_gc_values);
675
676 // Track memory usage and detect low memory after GC finishes
677 MemoryService::track_memory_usage();
678
679 // Need to tell the epilogue code we are done with Full GC, regardless what was
680 // the initial value for "complete" flag.
681 gc_epilogue(true);
682
683 BiasedLocking::restore_marks();
684
685 print_heap_after_gc();
686 }
687 }
688
689 bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab,
690 GenCollectedHeap::GenerationType max_gen) const {
691 return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab);
692 }
693
694 void GenCollectedHeap::register_nmethod(nmethod* nm) {
695 ScavengableNMethods::register_nmethod(nm);
696 }
697
698 void GenCollectedHeap::unregister_nmethod(nmethod* nm) {
699 ScavengableNMethods::unregister_nmethod(nm);
700 }
701
702 void GenCollectedHeap::verify_nmethod(nmethod* nm) {
703 ScavengableNMethods::verify_nmethod(nm);
704 }
705
706 void GenCollectedHeap::flush_nmethod(nmethod* nm) {
707 // Do nothing.
708 }
709
710 void GenCollectedHeap::prune_scavengable_nmethods() {
711 ScavengableNMethods::prune_nmethods();
712 }
713
714 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
715 GCCauseSetter x(this, GCCause::_allocation_failure);
716 HeapWord* result = NULL;
717
718 assert(size != 0, "Precondition violated");
719 if (GCLocker::is_active_and_needs_gc()) {
720 // GC locker is active; instead of a collection we will attempt
721 // to expand the heap, if there's room for expansion.
722 if (!is_maximal_no_gc()) {
723 result = expand_heap_and_allocate(size, is_tlab);
724 }
725 return result; // Could be null if we are out of space.
726 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) {
727 // Do an incremental collection.
728 do_collection(false, // full
729 false, // clear_all_soft_refs
730 size, // size
731 is_tlab, // is_tlab
732 GenCollectedHeap::OldGen); // max_generation
733 } else {
734 log_trace(gc)(" :: Trying full because partial may fail :: ");
735 // Try a full collection; see delta for bug id 6266275
736 // for the original code and why this has been simplified
737 // with from-space allocation criteria modified and
738 // such allocation moved out of the safepoint path.
739 do_collection(true, // full
740 false, // clear_all_soft_refs
741 size, // size
742 is_tlab, // is_tlab
743 GenCollectedHeap::OldGen); // max_generation
744 }
745
746 result = attempt_allocation(size, is_tlab, false /*first_only*/);
747
748 if (result != NULL) {
749 assert(is_in_reserved(result), "result not in heap");
750 return result;
751 }
752
753 // OK, collection failed, try expansion.
754 result = expand_heap_and_allocate(size, is_tlab);
755 if (result != NULL) {
756 return result;
757 }
758
759 // If we reach this point, we're really out of memory. Try every trick
760 // we can to reclaim memory. Force collection of soft references. Force
761 // a complete compaction of the heap. Any additional methods for finding
762 // free memory should be here, especially if they are expensive. If this
763 // attempt fails, an OOM exception will be thrown.
764 {
765 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
766
767 do_collection(true, // full
768 true, // clear_all_soft_refs
769 size, // size
770 is_tlab, // is_tlab
771 GenCollectedHeap::OldGen); // max_generation
772 }
773
774 result = attempt_allocation(size, is_tlab, false /* first_only */);
775 if (result != NULL) {
776 assert(is_in_reserved(result), "result not in heap");
777 return result;
778 }
779
780 assert(!soft_ref_policy()->should_clear_all_soft_refs(),
781 "Flag should have been handled and cleared prior to this point");
782
783 // What else? We might try synchronous finalization later. If the total
784 // space available is large enough for the allocation, then a more
785 // complete compaction phase than we've tried so far might be
786 // appropriate.
787 return NULL;
788 }
789
790 #ifdef ASSERT
791 class AssertNonScavengableClosure: public OopClosure {
792 public:
793 virtual void do_oop(oop* p) {
794 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
795 "Referent should not be scavengable."); }
796 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
797 };
798 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
799 #endif
800
801 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
802 ScanningOption so,
803 OopClosure* strong_roots,
804 CLDClosure* strong_cld_closure,
805 CLDClosure* weak_cld_closure,
806 CodeBlobToOopClosure* code_roots) {
807 // General roots.
808 assert(code_roots != NULL, "code root closure should always be set");
809 // _n_termination for _process_strong_tasks should be set up stream
810 // in a method not running in a GC worker. Otherwise the GC worker
811 // could be trying to change the termination condition while the task
812 // is executing in another GC worker.
813
814 if (_process_strong_tasks->try_claim_task(GCH_PS_ClassLoaderDataGraph_oops_do)) {
815 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
816 }
817
818 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
819 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
820
821 bool is_par = scope->n_threads() > 1;
822 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
823
824 if (_process_strong_tasks->try_claim_task(GCH_PS_Universe_oops_do)) {
825 Universe::oops_do(strong_roots);
826 }
827
828 if (_process_strong_tasks->try_claim_task(GCH_PS_ObjectSynchronizer_oops_do)) {
829 ObjectSynchronizer::oops_do(strong_roots);
830 }
831 #if INCLUDE_AOT
832 if (UseAOT && _process_strong_tasks->try_claim_task(GCH_PS_aot_oops_do)) {
833 AOTLoader::oops_do(strong_roots);
834 }
835 #endif
836 if (_process_strong_tasks->try_claim_task(GCH_PS_OopStorageSet_oops_do)) {
837 OopStorageSet::strong_oops_do(strong_roots);
838 }
839
840 if (_process_strong_tasks->try_claim_task(GCH_PS_CodeCache_oops_do)) {
841 if (so & SO_ScavengeCodeCache) {
842 assert(code_roots != NULL, "must supply closure for code cache");
843
844 // We only visit parts of the CodeCache when scavenging.
845 ScavengableNMethods::nmethods_do(code_roots);
846 }
847 if (so & SO_AllCodeCache) {
848 assert(code_roots != NULL, "must supply closure for code cache");
849
850 // CMSCollector uses this to do intermediate-strength collections.
851 // We scan the entire code cache, since CodeCache::do_unloading is not called.
852 CodeCache::blobs_do(code_roots);
853 }
854 // Verify that the code cache contents are not subject to
855 // movement by a scavenging collection.
856 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
857 DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
858 }
859 }
860
861 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
862 OopsInGenClosure* root_closure,
863 OopsInGenClosure* old_gen_closure,
864 CLDClosure* cld_closure) {
865 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
866
867 process_roots(scope, SO_ScavengeCodeCache, root_closure,
868 cld_closure, cld_closure, &mark_code_closure);
869
870 if (_process_strong_tasks->try_claim_task(GCH_PS_younger_gens)) {
871 root_closure->reset_generation();
872 }
873
874 // When collection is parallel, all threads get to cooperate to do
875 // old generation scanning.
876 old_gen_closure->set_generation(_old_gen);
877 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
878 old_gen_closure->reset_generation();
879
880 _process_strong_tasks->all_tasks_completed(scope->n_threads());
881 }
882
883 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
884 bool is_adjust_phase,
885 ScanningOption so,
886 bool only_strong_roots,
887 OopsInGenClosure* root_closure,
888 CLDClosure* cld_closure) {
889 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
890 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
891
892 process_roots(scope, so, root_closure, cld_closure, weak_cld_closure, &mark_code_closure);
893 _process_strong_tasks->all_tasks_completed(scope->n_threads());
894 }
895
896 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
897 WeakProcessor::oops_do(root_closure);
898 _young_gen->ref_processor()->weak_oops_do(root_closure);
899 _old_gen->ref_processor()->weak_oops_do(root_closure);
900 }
901
902 bool GenCollectedHeap::no_allocs_since_save_marks() {
903 return _young_gen->no_allocs_since_save_marks() &&
904 _old_gen->no_allocs_since_save_marks();
905 }
906
907 bool GenCollectedHeap::supports_inline_contig_alloc() const {
908 return _young_gen->supports_inline_contig_alloc();
909 }
910
911 HeapWord* volatile* GenCollectedHeap::top_addr() const {
912 return _young_gen->top_addr();
913 }
914
915 HeapWord** GenCollectedHeap::end_addr() const {
916 return _young_gen->end_addr();
917 }
918
919 // public collection interfaces
920
921 void GenCollectedHeap::collect(GCCause::Cause cause) {
922 if ((cause == GCCause::_wb_young_gc) ||
923 (cause == GCCause::_gc_locker)) {
924 // Young collection for WhiteBox or GCLocker.
925 collect(cause, YoungGen);
926 } else {
927 #ifdef ASSERT
928 if (cause == GCCause::_scavenge_alot) {
929 // Young collection only.
930 collect(cause, YoungGen);
931 } else {
932 // Stop-the-world full collection.
933 collect(cause, OldGen);
934 }
935 #else
936 // Stop-the-world full collection.
937 collect(cause, OldGen);
938 #endif
939 }
940 }
941
942 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
943 // The caller doesn't have the Heap_lock
944 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
945 MutexLocker ml(Heap_lock);
946 collect_locked(cause, max_generation);
947 }
948
949 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
950 // The caller has the Heap_lock
951 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
952 collect_locked(cause, OldGen);
953 }
954
955 // this is the private collection interface
956 // The Heap_lock is expected to be held on entry.
957
958 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
959 // Read the GC count while holding the Heap_lock
960 unsigned int gc_count_before = total_collections();
961 unsigned int full_gc_count_before = total_full_collections();
962
963 if (GCLocker::should_discard(cause, gc_count_before)) {
964 return;
965 }
966
967 {
968 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
969 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
970 cause, max_generation);
971 VMThread::execute(&op);
972 }
973 }
974
975 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
976 do_full_collection(clear_all_soft_refs, OldGen);
977 }
978
979 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
980 GenerationType last_generation) {
981 do_collection(true, // full
982 clear_all_soft_refs, // clear_all_soft_refs
983 0, // size
984 false, // is_tlab
985 last_generation); // last_generation
986 // Hack XXX FIX ME !!!
987 // A scavenge may not have been attempted, or may have
988 // been attempted and failed, because the old gen was too full
989 if (gc_cause() == GCCause::_gc_locker && incremental_collection_failed()) {
990 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
991 // This time allow the old gen to be collected as well
992 do_collection(true, // full
993 clear_all_soft_refs, // clear_all_soft_refs
994 0, // size
995 false, // is_tlab
996 OldGen); // last_generation
997 }
998 }
999
1000 bool GenCollectedHeap::is_in_young(oop p) {
1001 bool result = cast_from_oop<HeapWord*>(p) < _old_gen->reserved().start();
1002 assert(result == _young_gen->is_in_reserved(p),
1003 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
1004 return result;
1005 }
1006
1007 // Returns "TRUE" iff "p" points into the committed areas of the heap.
1008 bool GenCollectedHeap::is_in(const void* p) const {
1009 return _young_gen->is_in(p) || _old_gen->is_in(p);
1010 }
1011
1012 #ifdef ASSERT
1013 // Don't implement this by using is_in_young(). This method is used
1014 // in some cases to check that is_in_young() is correct.
1015 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
1016 assert(is_in_reserved(p) || p == NULL,
1017 "Does not work if address is non-null and outside of the heap");
1018 return p < _young_gen->reserved().end() && p != NULL;
1019 }
1020 #endif
1021
1022 void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) {
1023 _young_gen->oop_iterate(cl);
1024 _old_gen->oop_iterate(cl);
1025 }
1026
1027 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
1028 _young_gen->object_iterate(cl);
1029 _old_gen->object_iterate(cl);
1030 }
1031
1032 Space* GenCollectedHeap::space_containing(const void* addr) const {
1033 Space* res = _young_gen->space_containing(addr);
1034 if (res != NULL) {
1035 return res;
1036 }
1037 res = _old_gen->space_containing(addr);
1038 assert(res != NULL, "Could not find containing space");
1039 return res;
1040 }
1041
1042 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1043 assert(is_in_reserved(addr), "block_start of address outside of heap");
1044 if (_young_gen->is_in_reserved(addr)) {
1045 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
1046 return _young_gen->block_start(addr);
1047 }
1048
1049 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1050 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
1051 return _old_gen->block_start(addr);
1052 }
1053
1054 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1055 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1056 assert(block_start(addr) == addr, "addr must be a block start");
1057 if (_young_gen->is_in_reserved(addr)) {
1058 return _young_gen->block_is_obj(addr);
1059 }
1060
1061 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1062 return _old_gen->block_is_obj(addr);
1063 }
1064
1065 bool GenCollectedHeap::supports_tlab_allocation() const {
1066 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1067 return _young_gen->supports_tlab_allocation();
1068 }
1069
1070 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1071 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1072 if (_young_gen->supports_tlab_allocation()) {
1073 return _young_gen->tlab_capacity();
1074 }
1075 return 0;
1076 }
1077
1078 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1079 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1080 if (_young_gen->supports_tlab_allocation()) {
1081 return _young_gen->tlab_used();
1082 }
1083 return 0;
1084 }
1085
1086 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1087 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1088 if (_young_gen->supports_tlab_allocation()) {
1089 return _young_gen->unsafe_max_tlab_alloc();
1090 }
1091 return 0;
1092 }
1093
1094 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size,
1095 size_t requested_size,
1096 size_t* actual_size) {
1097 bool gc_overhead_limit_was_exceeded;
1098 HeapWord* result = mem_allocate_work(requested_size /* size */,
1099 true /* is_tlab */,
1100 &gc_overhead_limit_was_exceeded);
1101 if (result != NULL) {
1102 *actual_size = requested_size;
1103 }
1104
1105 return result;
1106 }
1107
1108 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1109 // from the list headed by "*prev_ptr".
1110 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1111 bool first = true;
1112 size_t min_size = 0; // "first" makes this conceptually infinite.
1113 ScratchBlock **smallest_ptr, *smallest;
1114 ScratchBlock *cur = *prev_ptr;
1115 while (cur) {
1116 assert(*prev_ptr == cur, "just checking");
1117 if (first || cur->num_words < min_size) {
1118 smallest_ptr = prev_ptr;
1119 smallest = cur;
1120 min_size = smallest->num_words;
1121 first = false;
1122 }
1123 prev_ptr = &cur->next;
1124 cur = cur->next;
1125 }
1126 smallest = *smallest_ptr;
1127 *smallest_ptr = smallest->next;
1128 return smallest;
1129 }
1130
1131 // Sort the scratch block list headed by res into decreasing size order,
1132 // and set "res" to the result.
1133 static void sort_scratch_list(ScratchBlock*& list) {
1134 ScratchBlock* sorted = NULL;
1135 ScratchBlock* unsorted = list;
1136 while (unsorted) {
1137 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1138 smallest->next = sorted;
1139 sorted = smallest;
1140 }
1141 list = sorted;
1142 }
1143
1144 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1145 size_t max_alloc_words) {
1146 ScratchBlock* res = NULL;
1147 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1148 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1149 sort_scratch_list(res);
1150 return res;
1151 }
1152
1153 void GenCollectedHeap::release_scratch() {
1154 _young_gen->reset_scratch();
1155 _old_gen->reset_scratch();
1156 }
1157
1158 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1159 void do_generation(Generation* gen) {
1160 gen->prepare_for_verify();
1161 }
1162 };
1163
1164 void GenCollectedHeap::prepare_for_verify() {
1165 ensure_parsability(false); // no need to retire TLABs
1166 GenPrepareForVerifyClosure blk;
1167 generation_iterate(&blk, false);
1168 }
1169
1170 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1171 bool old_to_young) {
1172 if (old_to_young) {
1173 cl->do_generation(_old_gen);
1174 cl->do_generation(_young_gen);
1175 } else {
1176 cl->do_generation(_young_gen);
1177 cl->do_generation(_old_gen);
1178 }
1179 }
1180
1181 bool GenCollectedHeap::is_maximal_no_gc() const {
1182 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1183 }
1184
1185 void GenCollectedHeap::save_marks() {
1186 _young_gen->save_marks();
1187 _old_gen->save_marks();
1188 }
1189
1190 GenCollectedHeap* GenCollectedHeap::heap() {
1191 // SerialHeap is the only subtype of GenCollectedHeap.
1192 return named_heap<GenCollectedHeap>(CollectedHeap::Serial);
1193 }
1194
1195 #if INCLUDE_SERIALGC
1196 void GenCollectedHeap::prepare_for_compaction() {
1197 // Start by compacting into same gen.
1198 CompactPoint cp(_old_gen);
1199 _old_gen->prepare_for_compaction(&cp);
1200 _young_gen->prepare_for_compaction(&cp);
1201 }
1202 #endif // INCLUDE_SERIALGC
1203
1204 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1205 log_debug(gc, verify)("%s", _old_gen->name());
1206 _old_gen->verify();
1207
1208 log_debug(gc, verify)("%s", _old_gen->name());
1209 _young_gen->verify();
1210
1211 log_debug(gc, verify)("RemSet");
1212 rem_set()->verify();
1213 }
1214
1215 void GenCollectedHeap::print_on(outputStream* st) const {
1216 if (_young_gen != NULL) {
1217 _young_gen->print_on(st);
1218 }
1219 if (_old_gen != NULL) {
1220 _old_gen->print_on(st);
1221 }
1222 MetaspaceUtils::print_on(st);
1223 }
1224
1225 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1226 }
1227
1228 bool GenCollectedHeap::print_location(outputStream* st, void* addr) const {
1229 return BlockLocationPrinter<GenCollectedHeap>::print_location(st, addr);
1230 }
1231
1232 void GenCollectedHeap::print_tracing_info() const {
1233 if (log_is_enabled(Debug, gc, heap, exit)) {
1234 LogStreamHandle(Debug, gc, heap, exit) lsh;
1235 _young_gen->print_summary_info_on(&lsh);
1236 _old_gen->print_summary_info_on(&lsh);
1237 }
1238 }
1239
1240 void GenCollectedHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const {
1241 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
1242
1243 log_info(gc, heap)(HEAP_CHANGE_FORMAT" "
1244 HEAP_CHANGE_FORMAT" "
1245 HEAP_CHANGE_FORMAT,
1246 HEAP_CHANGE_FORMAT_ARGS(def_new_gen->short_name(),
1247 pre_gc_values.young_gen_used(),
1248 pre_gc_values.young_gen_capacity(),
1249 def_new_gen->used(),
1250 def_new_gen->capacity()),
1251 HEAP_CHANGE_FORMAT_ARGS("Eden",
1252 pre_gc_values.eden_used(),
1253 pre_gc_values.eden_capacity(),
1254 def_new_gen->eden()->used(),
1255 def_new_gen->eden()->capacity()),
1256 HEAP_CHANGE_FORMAT_ARGS("From",
1257 pre_gc_values.from_used(),
1258 pre_gc_values.from_capacity(),
1259 def_new_gen->from()->used(),
1260 def_new_gen->from()->capacity()));
1261 log_info(gc, heap)(HEAP_CHANGE_FORMAT,
1262 HEAP_CHANGE_FORMAT_ARGS(old_gen()->short_name(),
1263 pre_gc_values.old_gen_used(),
1264 pre_gc_values.old_gen_capacity(),
1265 old_gen()->used(),
1266 old_gen()->capacity()));
1267 MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes());
1268 }
1269
1270 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1271 private:
1272 bool _full;
1273 public:
1274 void do_generation(Generation* gen) {
1275 gen->gc_prologue(_full);
1276 }
1277 GenGCPrologueClosure(bool full) : _full(full) {};
1278 };
1279
1280 void GenCollectedHeap::gc_prologue(bool full) {
1281 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1282
1283 // Fill TLAB's and such
1284 ensure_parsability(true); // retire TLABs
1285
1286 // Walk generations
1287 GenGCPrologueClosure blk(full);
1288 generation_iterate(&blk, false); // not old-to-young.
1289 };
1290
1291 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1292 private:
1293 bool _full;
1294 public:
1295 void do_generation(Generation* gen) {
1296 gen->gc_epilogue(_full);
1297 }
1298 GenGCEpilogueClosure(bool full) : _full(full) {};
1299 };
1300
1301 void GenCollectedHeap::gc_epilogue(bool full) {
1302 #if COMPILER2_OR_JVMCI
1303 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1304 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1305 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1306 #endif // COMPILER2_OR_JVMCI
1307
1308 resize_all_tlabs();
1309
1310 GenGCEpilogueClosure blk(full);
1311 generation_iterate(&blk, false); // not old-to-young.
1312
1313 if (!CleanChunkPoolAsync) {
1314 Chunk::clean_chunk_pool();
1315 }
1316
1317 MetaspaceCounters::update_performance_counters();
1318 CompressedClassSpaceCounters::update_performance_counters();
1319 };
1320
1321 #ifndef PRODUCT
1322 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1323 private:
1324 public:
1325 void do_generation(Generation* gen) {
1326 gen->record_spaces_top();
1327 }
1328 };
1329
1330 void GenCollectedHeap::record_gen_tops_before_GC() {
1331 if (ZapUnusedHeapArea) {
1332 GenGCSaveTopsBeforeGCClosure blk;
1333 generation_iterate(&blk, false); // not old-to-young.
1334 }
1335 }
1336 #endif // not PRODUCT
1337
1338 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1339 public:
1340 void do_generation(Generation* gen) {
1341 gen->ensure_parsability();
1342 }
1343 };
1344
1345 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1346 CollectedHeap::ensure_parsability(retire_tlabs);
1347 GenEnsureParsabilityClosure ep_cl;
1348 generation_iterate(&ep_cl, false);
1349 }
1350
1351 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1352 oop obj,
1353 size_t obj_size) {
1354 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1355 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1356 HeapWord* result = NULL;
1357
1358 result = old_gen->expand_and_allocate(obj_size, false);
1359
1360 if (result != NULL) {
1361 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), result, obj_size);
1362 }
1363 return oop(result);
1364 }
1365
1366 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1367 jlong _time; // in ms
1368 jlong _now; // in ms
1369
1370 public:
1371 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1372
1373 jlong time() { return _time; }
1374
1375 void do_generation(Generation* gen) {
1376 _time = MIN2(_time, gen->time_of_last_gc(_now));
1377 }
1378 };
1379
1380 jlong GenCollectedHeap::millis_since_last_gc() {
1381 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1382 // provided the underlying platform provides such a time source
1383 // (and it is bug free). So we still have to guard against getting
1384 // back a time later than 'now'.
1385 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1386 GenTimeOfLastGCClosure tolgc_cl(now);
1387 // iterate over generations getting the oldest
1388 // time that a generation was collected
1389 generation_iterate(&tolgc_cl, false);
1390
1391 jlong retVal = now - tolgc_cl.time();
1392 if (retVal < 0) {
1393 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1394 ". returning zero instead.", retVal);
1395 return 0;
1396 }
1397 return retVal;
1398 }