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/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/icBuffer.hpp"
34 #include "gc/serial/defNewGeneration.hpp"
35 #include "gc/shared/adaptiveSizePolicy.hpp"
36 #include "gc/shared/cardTableBarrierSet.hpp"
37 #include "gc/shared/cardTableRS.hpp"
38 #include "gc/shared/collectedHeap.inline.hpp"
39 #include "gc/shared/collectorCounters.hpp"
40 #include "gc/shared/gcId.hpp"
41 #include "gc/shared/gcLocker.hpp"
42 #include "gc/shared/gcPolicyCounters.hpp"
43 #include "gc/shared/gcTrace.hpp"
44 #include "gc/shared/gcTraceTime.inline.hpp"
45 #include "gc/shared/genArguments.hpp"
46 #include "gc/shared/gcVMOperations.hpp"
47 #include "gc/shared/genCollectedHeap.hpp"
48 #include "gc/shared/genOopClosures.inline.hpp"
49 #include "gc/shared/generationSpec.hpp"
50 #include "gc/shared/initLogger.hpp"
51 #include "gc/shared/locationPrinter.inline.hpp"
52 #include "gc/shared/oopStorageParState.inline.hpp"
53 #include "gc/shared/scavengableNMethods.hpp"
54 #include "gc/shared/space.hpp"
55 #include "gc/shared/strongRootsScope.hpp"
56 #include "gc/shared/weakProcessor.hpp"
57 #include "gc/shared/workgroup.hpp"
58 #include "memory/filemap.hpp"
59 #include "memory/iterator.hpp"
60 #include "memory/metaspaceCounters.hpp"
61 #include "memory/resourceArea.hpp"
62 #include "memory/universe.hpp"
63 #include "oops/oop.inline.hpp"
64 #include "runtime/biasedLocking.hpp"
65 #include "runtime/flags/flagSetting.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/management.hpp"
71 #include "services/memoryService.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_spec(new GenerationSpec(young,
86 NewSize,
87 MaxNewSize,
88 GenAlignment)),
89 _old_gen_spec(new GenerationSpec(old,
90 OldSize,
91 MaxOldSize,
92 GenAlignment)),
93 _rem_set(NULL),
94 _soft_ref_gen_policy(),
95 _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)),
96 _full_collections_completed(0),
97 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)) {
98 }
99
100 jint GenCollectedHeap::initialize() {
101 // While there are no constraints in the GC code that HeapWordSize
102 // be any particular value, there are multiple other areas in the
103 // system which believe this to be true (e.g. oop->object_size in some
104 // cases incorrectly returns the size in wordSize units rather than
105 // HeapWordSize).
106 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
107
108 // Allocate space for the heap.
109
110 ReservedHeapSpace heap_rs = allocate(HeapAlignment);
111
112 if (!heap_rs.is_reserved()) {
113 vm_shutdown_during_initialization(
114 "Could not reserve enough space for object heap");
115 return JNI_ENOMEM;
116 }
117
118 initialize_reserved_region(heap_rs);
119
120 _rem_set = create_rem_set(heap_rs.region());
121 _rem_set->initialize();
122 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set);
123 bs->initialize();
124 BarrierSet::set_barrier_set(bs);
125
126 ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size(), false, false);
127 _young_gen = _young_gen_spec->init(young_rs, rem_set());
128 ReservedSpace old_rs = heap_rs.last_part(_young_gen_spec->max_size());
129
130 old_rs = old_rs.first_part(_old_gen_spec->max_size(), false, false);
131 _old_gen = _old_gen_spec->init(old_rs, rem_set());
132 clear_incremental_collection_failed();
133
134 InitLogger::print();
135
136 return JNI_OK;
137 }
138
139 CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) {
140 return new CardTableRS(reserved_region, false /* scan_concurrently */);
141 }
142
143 void GenCollectedHeap::initialize_size_policy(size_t init_eden_size,
144 size_t init_promo_size,
145 size_t init_survivor_size) {
146 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
147 _size_policy = new AdaptiveSizePolicy(init_eden_size,
148 init_promo_size,
149 init_survivor_size,
150 max_gc_pause_sec,
151 GCTimeRatio);
152 }
153
154 ReservedHeapSpace GenCollectedHeap::allocate(size_t alignment) {
155 // Now figure out the total size.
156 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
157 assert(alignment % pageSize == 0, "Must be");
158
159 // Check for overflow.
160 size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size();
161 if (total_reserved < _young_gen_spec->max_size()) {
162 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
163 "the maximum representable size");
164 }
165 assert(total_reserved % alignment == 0,
166 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
167 SIZE_FORMAT, total_reserved, alignment);
168
169 ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment);
170
171 os::trace_page_sizes("Heap",
172 MinHeapSize,
173 total_reserved,
174 alignment,
175 heap_rs.base(),
176 heap_rs.size());
177
178 return heap_rs;
179 }
180
181 class GenIsScavengable : public BoolObjectClosure {
182 public:
183 bool do_object_b(oop obj) {
184 return GenCollectedHeap::heap()->is_in_young(obj);
185 }
186 };
187
188 static GenIsScavengable _is_scavengable;
189
190 void GenCollectedHeap::post_initialize() {
191 CollectedHeap::post_initialize();
192 ref_processing_init();
193
194 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
195
196 initialize_size_policy(def_new_gen->eden()->capacity(),
197 _old_gen->capacity(),
198 def_new_gen->from()->capacity());
199
200 MarkSweep::initialize();
201
202 ScavengableNMethods::initialize(&_is_scavengable);
203 }
204
205 void GenCollectedHeap::ref_processing_init() {
206 _young_gen->ref_processor_init();
207 _old_gen->ref_processor_init();
208 }
209
210 PreGenGCValues GenCollectedHeap::get_pre_gc_values() const {
211 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
212
213 return PreGenGCValues(def_new_gen->used(),
214 def_new_gen->capacity(),
215 def_new_gen->eden()->used(),
216 def_new_gen->eden()->capacity(),
217 def_new_gen->from()->used(),
218 def_new_gen->from()->capacity(),
219 old_gen()->used(),
220 old_gen()->capacity());
221 }
222
223 GenerationSpec* GenCollectedHeap::young_gen_spec() const {
224 return _young_gen_spec;
225 }
226
227 GenerationSpec* GenCollectedHeap::old_gen_spec() const {
228 return _old_gen_spec;
229 }
230
231 size_t GenCollectedHeap::capacity() const {
232 return _young_gen->capacity() + _old_gen->capacity();
233 }
234
235 size_t GenCollectedHeap::used() const {
236 return _young_gen->used() + _old_gen->used();
237 }
238
239 void GenCollectedHeap::save_used_regions() {
240 _old_gen->save_used_region();
241 _young_gen->save_used_region();
242 }
243
244 size_t GenCollectedHeap::max_capacity() const {
245 return _young_gen->max_capacity() + _old_gen->max_capacity();
246 }
247
248 // Update the _full_collections_completed counter
249 // at the end of a stop-world full GC.
250 unsigned int GenCollectedHeap::update_full_collections_completed() {
251 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
252 assert(_full_collections_completed <= _total_full_collections,
253 "Can't complete more collections than were started");
254 _full_collections_completed = _total_full_collections;
255 ml.notify_all();
256 return _full_collections_completed;
257 }
258
259 // Update the _full_collections_completed counter, as appropriate,
260 // at the end of a concurrent GC cycle. Note the conditional update
261 // below to allow this method to be called by a concurrent collector
262 // without synchronizing in any manner with the VM thread (which
263 // may already have initiated a STW full collection "concurrently").
264 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
265 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
266 assert((_full_collections_completed <= _total_full_collections) &&
267 (count <= _total_full_collections),
268 "Can't complete more collections than were started");
269 if (count > _full_collections_completed) {
270 _full_collections_completed = count;
271 ml.notify_all();
272 }
273 return _full_collections_completed;
274 }
275
276 // Return true if any of the following is true:
277 // . the allocation won't fit into the current young gen heap
278 // . gc locker is occupied (jni critical section)
279 // . heap memory is tight -- the most recent previous collection
280 // was a full collection because a partial collection (would
281 // have) failed and is likely to fail again
282 bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const {
283 size_t young_capacity = _young_gen->capacity_before_gc();
284 return (word_size > heap_word_size(young_capacity))
285 || GCLocker::is_active_and_needs_gc()
286 || incremental_collection_failed();
287 }
288
289 HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) {
290 HeapWord* result = NULL;
291 if (_old_gen->should_allocate(size, is_tlab)) {
292 result = _old_gen->expand_and_allocate(size, is_tlab);
293 }
294 if (result == NULL) {
295 if (_young_gen->should_allocate(size, is_tlab)) {
296 result = _young_gen->expand_and_allocate(size, is_tlab);
297 }
298 }
299 assert(result == NULL || is_in_reserved(result), "result not in heap");
300 return result;
301 }
302
303 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size,
304 bool is_tlab,
305 bool* gc_overhead_limit_was_exceeded) {
306 // In general gc_overhead_limit_was_exceeded should be false so
307 // set it so here and reset it to true only if the gc time
308 // limit is being exceeded as checked below.
309 *gc_overhead_limit_was_exceeded = false;
310
311 HeapWord* result = NULL;
312
313 // Loop until the allocation is satisfied, or unsatisfied after GC.
314 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
315 HandleMark hm; // Discard any handles allocated in each iteration.
316
317 // First allocation attempt is lock-free.
318 Generation *young = _young_gen;
319 assert(young->supports_inline_contig_alloc(),
320 "Otherwise, must do alloc within heap lock");
321 if (young->should_allocate(size, is_tlab)) {
322 result = young->par_allocate(size, is_tlab);
323 if (result != NULL) {
324 assert(is_in_reserved(result), "result not in heap");
325 return result;
326 }
327 }
328 uint gc_count_before; // Read inside the Heap_lock locked region.
329 {
330 MutexLocker ml(Heap_lock);
331 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation");
332 // Note that only large objects get a shot at being
333 // allocated in later generations.
334 bool first_only = !should_try_older_generation_allocation(size);
335
336 result = attempt_allocation(size, is_tlab, first_only);
337 if (result != NULL) {
338 assert(is_in_reserved(result), "result not in heap");
339 return result;
340 }
341
342 if (GCLocker::is_active_and_needs_gc()) {
343 if (is_tlab) {
344 return NULL; // Caller will retry allocating individual object.
345 }
346 if (!is_maximal_no_gc()) {
347 // Try and expand heap to satisfy request.
348 result = expand_heap_and_allocate(size, is_tlab);
349 // Result could be null if we are out of space.
350 if (result != NULL) {
351 return result;
352 }
353 }
354
355 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
356 return NULL; // We didn't get to do a GC and we didn't get any memory.
357 }
358
359 // If this thread is not in a jni critical section, we stall
360 // the requestor until the critical section has cleared and
361 // GC allowed. When the critical section clears, a GC is
362 // initiated by the last thread exiting the critical section; so
363 // we retry the allocation sequence from the beginning of the loop,
364 // rather than causing more, now probably unnecessary, GC attempts.
365 JavaThread* jthr = JavaThread::current();
366 if (!jthr->in_critical()) {
367 MutexUnlocker mul(Heap_lock);
368 // Wait for JNI critical section to be exited
369 GCLocker::stall_until_clear();
370 gclocker_stalled_count += 1;
371 continue;
372 } else {
373 if (CheckJNICalls) {
374 fatal("Possible deadlock due to allocating while"
375 " in jni critical section");
376 }
377 return NULL;
378 }
379 }
380
381 // Read the gc count while the heap lock is held.
382 gc_count_before = total_collections();
383 }
384
385 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
386 VMThread::execute(&op);
387 if (op.prologue_succeeded()) {
388 result = op.result();
389 if (op.gc_locked()) {
390 assert(result == NULL, "must be NULL if gc_locked() is true");
391 continue; // Retry and/or stall as necessary.
392 }
393
394 // Allocation has failed and a collection
395 // has been done. If the gc time limit was exceeded the
396 // this time, return NULL so that an out-of-memory
397 // will be thrown. Clear gc_overhead_limit_exceeded
398 // so that the overhead exceeded does not persist.
399
400 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
401 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear();
402
403 if (limit_exceeded && softrefs_clear) {
404 *gc_overhead_limit_was_exceeded = true;
405 size_policy()->set_gc_overhead_limit_exceeded(false);
406 if (op.result() != NULL) {
407 CollectedHeap::fill_with_object(op.result(), size);
408 }
409 return NULL;
410 }
411 assert(result == NULL || is_in_reserved(result),
412 "result not in heap");
413 return result;
414 }
415
416 // Give a warning if we seem to be looping forever.
417 if ((QueuedAllocationWarningCount > 0) &&
418 (try_count % QueuedAllocationWarningCount == 0)) {
419 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times,"
420 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : "");
421 }
422 }
423 }
424
425 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
426 bool is_tlab,
427 bool first_only) {
428 HeapWord* res = NULL;
429
430 if (_young_gen->should_allocate(size, is_tlab)) {
431 res = _young_gen->allocate(size, is_tlab);
432 if (res != NULL || first_only) {
433 return res;
434 }
435 }
436
437 if (_old_gen->should_allocate(size, is_tlab)) {
438 res = _old_gen->allocate(size, is_tlab);
439 }
440
441 return res;
442 }
443
444 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
445 bool* gc_overhead_limit_was_exceeded) {
446 return mem_allocate_work(size,
447 false /* is_tlab */,
448 gc_overhead_limit_was_exceeded);
449 }
450
451 bool GenCollectedHeap::must_clear_all_soft_refs() {
452 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
453 _gc_cause == GCCause::_wb_full_gc;
454 }
455
456 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
457 bool is_tlab, bool run_verification, bool clear_soft_refs,
458 bool restore_marks_for_biased_locking) {
459 FormatBuffer<> title("Collect gen: %s", gen->short_name());
460 GCTraceTime(Trace, gc, phases) t1(title);
461 TraceCollectorStats tcs(gen->counters());
462 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause());
463
464 gen->stat_record()->invocations++;
465 gen->stat_record()->accumulated_time.start();
466
467 // Must be done anew before each collection because
468 // a previous collection will do mangling and will
469 // change top of some spaces.
470 record_gen_tops_before_GC();
471
472 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
473
474 if (run_verification && VerifyBeforeGC) {
475 HandleMark hm; // Discard invalid handles created during verification
476 Universe::verify("Before GC");
477 }
478 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear());
479
480 if (restore_marks_for_biased_locking) {
481 // We perform this mark word preservation work lazily
482 // because it's only at this point that we know whether we
483 // absolutely have to do it; we want to avoid doing it for
484 // scavenge-only collections where it's unnecessary
485 BiasedLocking::preserve_marks();
486 }
487
488 // Do collection work
489 {
490 // Note on ref discovery: For what appear to be historical reasons,
491 // GCH enables and disabled (by enqueing) refs discovery.
492 // In the future this should be moved into the generation's
493 // collect method so that ref discovery and enqueueing concerns
494 // are local to a generation. The collect method could return
495 // an appropriate indication in the case that notification on
496 // the ref lock was needed. This will make the treatment of
497 // weak refs more uniform (and indeed remove such concerns
498 // from GCH). XXX
499
500 HandleMark hm; // Discard invalid handles created during gc
501 save_marks(); // save marks for all gens
502 // We want to discover references, but not process them yet.
503 // This mode is disabled in process_discovered_references if the
504 // generation does some collection work, or in
505 // enqueue_discovered_references if the generation returns
506 // without doing any work.
507 ReferenceProcessor* rp = gen->ref_processor();
508 // If the discovery of ("weak") refs in this generation is
509 // atomic wrt other collectors in this configuration, we
510 // are guaranteed to have empty discovered ref lists.
511 if (rp->discovery_is_atomic()) {
512 rp->enable_discovery();
513 rp->setup_policy(clear_soft_refs);
514 } else {
515 // collect() below will enable discovery as appropriate
516 }
517 gen->collect(full, clear_soft_refs, size, is_tlab);
518 if (!rp->enqueuing_is_done()) {
519 rp->disable_discovery();
520 } else {
521 rp->set_enqueuing_is_done(false);
522 }
523 rp->verify_no_references_recorded();
524 }
525
526 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers());
527
528 gen->stat_record()->accumulated_time.stop();
529
530 update_gc_stats(gen, full);
531
532 if (run_verification && VerifyAfterGC) {
533 HandleMark hm; // Discard invalid handles created during verification
534 Universe::verify("After GC");
535 }
536 }
537
538 void GenCollectedHeap::do_collection(bool full,
539 bool clear_all_soft_refs,
540 size_t size,
541 bool is_tlab,
542 GenerationType max_generation) {
543 ResourceMark rm;
544 DEBUG_ONLY(Thread* my_thread = Thread::current();)
545
546 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
547 assert(my_thread->is_VM_thread() ||
548 my_thread->is_ConcurrentGC_thread(),
549 "incorrect thread type capability");
550 assert(Heap_lock->is_locked(),
551 "the requesting thread should have the Heap_lock");
552 guarantee(!is_gc_active(), "collection is not reentrant");
553
554 if (GCLocker::check_active_before_gc()) {
555 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
556 }
557
558 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
559 soft_ref_policy()->should_clear_all_soft_refs();
560
561 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy());
562
563 FlagSetting fl(_is_gc_active, true);
564
565 bool complete = full && (max_generation == OldGen);
566 bool old_collects_young = complete && !ScavengeBeforeFullGC;
567 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
568
569 const PreGenGCValues pre_gc_values = get_pre_gc_values();
570
571 bool run_verification = total_collections() >= VerifyGCStartAt;
572 bool prepared_for_verification = false;
573 bool do_full_collection = false;
574
575 if (do_young_collection) {
576 GCIdMark gc_id_mark;
577 GCTraceCPUTime tcpu;
578 GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true);
579
580 print_heap_before_gc();
581
582 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
583 prepare_for_verify();
584 prepared_for_verification = true;
585 }
586
587 gc_prologue(complete);
588 increment_total_collections(complete);
589
590 collect_generation(_young_gen,
591 full,
592 size,
593 is_tlab,
594 run_verification && VerifyGCLevel <= 0,
595 do_clear_all_soft_refs,
596 false);
597
598 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
599 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
600 // Allocation request was met by young GC.
601 size = 0;
602 }
603
604 // Ask if young collection is enough. If so, do the final steps for young collection,
605 // and fallthrough to the end.
606 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
607 if (!do_full_collection) {
608 // Adjust generation sizes.
609 _young_gen->compute_new_size();
610
611 print_heap_change(pre_gc_values);
612
613 // Track memory usage and detect low memory after GC finishes
614 MemoryService::track_memory_usage();
615
616 gc_epilogue(complete);
617 }
618
619 print_heap_after_gc();
620
621 } else {
622 // No young collection, ask if we need to perform Full collection.
623 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
624 }
625
626 if (do_full_collection) {
627 GCIdMark gc_id_mark;
628 GCTraceCPUTime tcpu;
629 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
630
631 print_heap_before_gc();
632
633 if (!prepared_for_verification && run_verification &&
634 VerifyGCLevel <= 1 && VerifyBeforeGC) {
635 prepare_for_verify();
636 }
637
638 if (!do_young_collection) {
639 gc_prologue(complete);
640 increment_total_collections(complete);
641 }
642
643 // Accounting quirk: total full collections would be incremented when "complete"
644 // is set, by calling increment_total_collections above. However, we also need to
645 // account Full collections that had "complete" unset.
646 if (!complete) {
647 increment_total_full_collections();
648 }
649
650 collect_generation(_old_gen,
651 full,
652 size,
653 is_tlab,
654 run_verification && VerifyGCLevel <= 1,
655 do_clear_all_soft_refs,
656 true);
657
658 // Adjust generation sizes.
659 _old_gen->compute_new_size();
660 _young_gen->compute_new_size();
661
662 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
663 ClassLoaderDataGraph::purge();
664 MetaspaceUtils::verify_metrics();
665 // Resize the metaspace capacity after full collections
666 MetaspaceGC::compute_new_size();
667 update_full_collections_completed();
668
669 print_heap_change(pre_gc_values);
670
671 // Track memory usage and detect low memory after GC finishes
672 MemoryService::track_memory_usage();
673
674 // Need to tell the epilogue code we are done with Full GC, regardless what was
675 // the initial value for "complete" flag.
676 gc_epilogue(true);
677
678 BiasedLocking::restore_marks();
679
680 print_heap_after_gc();
681 }
682 }
683
684 bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab,
685 GenCollectedHeap::GenerationType max_gen) const {
686 return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab);
687 }
688
689 void GenCollectedHeap::register_nmethod(nmethod* nm) {
690 ScavengableNMethods::register_nmethod(nm);
691 }
692
693 void GenCollectedHeap::unregister_nmethod(nmethod* nm) {
694 ScavengableNMethods::unregister_nmethod(nm);
695 }
696
697 void GenCollectedHeap::verify_nmethod(nmethod* nm) {
698 ScavengableNMethods::verify_nmethod(nm);
699 }
700
701 void GenCollectedHeap::flush_nmethod(nmethod* nm) {
702 // Do nothing.
703 }
704
705 void GenCollectedHeap::prune_scavengable_nmethods() {
706 ScavengableNMethods::prune_nmethods();
707 }
708
709 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
710 GCCauseSetter x(this, GCCause::_allocation_failure);
711 HeapWord* result = NULL;
712
713 assert(size != 0, "Precondition violated");
714 if (GCLocker::is_active_and_needs_gc()) {
715 // GC locker is active; instead of a collection we will attempt
716 // to expand the heap, if there's room for expansion.
717 if (!is_maximal_no_gc()) {
718 result = expand_heap_and_allocate(size, is_tlab);
719 }
720 return result; // Could be null if we are out of space.
721 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) {
722 // Do an incremental collection.
723 do_collection(false, // full
724 false, // clear_all_soft_refs
725 size, // size
726 is_tlab, // is_tlab
727 GenCollectedHeap::OldGen); // max_generation
728 } else {
729 log_trace(gc)(" :: Trying full because partial may fail :: ");
730 // Try a full collection; see delta for bug id 6266275
731 // for the original code and why this has been simplified
732 // with from-space allocation criteria modified and
733 // such allocation moved out of the safepoint path.
734 do_collection(true, // full
735 false, // clear_all_soft_refs
736 size, // size
737 is_tlab, // is_tlab
738 GenCollectedHeap::OldGen); // max_generation
739 }
740
741 result = attempt_allocation(size, is_tlab, false /*first_only*/);
742
743 if (result != NULL) {
744 assert(is_in_reserved(result), "result not in heap");
745 return result;
746 }
747
748 // OK, collection failed, try expansion.
749 result = expand_heap_and_allocate(size, is_tlab);
750 if (result != NULL) {
751 return result;
752 }
753
754 // If we reach this point, we're really out of memory. Try every trick
755 // we can to reclaim memory. Force collection of soft references. Force
756 // a complete compaction of the heap. Any additional methods for finding
757 // free memory should be here, especially if they are expensive. If this
758 // attempt fails, an OOM exception will be thrown.
759 {
760 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
761
762 do_collection(true, // full
763 true, // clear_all_soft_refs
764 size, // size
765 is_tlab, // is_tlab
766 GenCollectedHeap::OldGen); // max_generation
767 }
768
769 result = attempt_allocation(size, is_tlab, false /* first_only */);
770 if (result != NULL) {
771 assert(is_in_reserved(result), "result not in heap");
772 return result;
773 }
774
775 assert(!soft_ref_policy()->should_clear_all_soft_refs(),
776 "Flag should have been handled and cleared prior to this point");
777
778 // What else? We might try synchronous finalization later. If the total
779 // space available is large enough for the allocation, then a more
780 // complete compaction phase than we've tried so far might be
781 // appropriate.
782 return NULL;
783 }
784
785 #ifdef ASSERT
786 class AssertNonScavengableClosure: public OopClosure {
787 public:
788 virtual void do_oop(oop* p) {
789 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
790 "Referent should not be scavengable."); }
791 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
792 };
793 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
794 #endif
795
796 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
797 ScanningOption so,
798 OopClosure* strong_roots,
799 CLDClosure* strong_cld_closure,
800 CLDClosure* weak_cld_closure,
801 CodeBlobToOopClosure* code_roots) {
802 // General roots.
803 assert(code_roots != NULL, "code root closure should always be set");
804 // _n_termination for _process_strong_tasks should be set up stream
805 // in a method not running in a GC worker. Otherwise the GC worker
806 // could be trying to change the termination condition while the task
807 // is executing in another GC worker.
808
809 if (_process_strong_tasks->try_claim_task(GCH_PS_ClassLoaderDataGraph_oops_do)) {
810 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
811 }
812
813 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
814 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
815
816 bool is_par = scope->n_threads() > 1;
817 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
818
819 if (_process_strong_tasks->try_claim_task(GCH_PS_Universe_oops_do)) {
820 Universe::oops_do(strong_roots);
821 }
822 // Global (strong) JNI handles
823 if (_process_strong_tasks->try_claim_task(GCH_PS_JNIHandles_oops_do)) {
824 JNIHandles::oops_do(strong_roots);
825 }
826
827 if (_process_strong_tasks->try_claim_task(GCH_PS_ObjectSynchronizer_oops_do)) {
828 ObjectSynchronizer::oops_do(strong_roots);
829 }
830 if (_process_strong_tasks->try_claim_task(GCH_PS_Management_oops_do)) {
831 Management::oops_do(strong_roots);
832 }
833 if (_process_strong_tasks->try_claim_task(GCH_PS_jvmti_oops_do)) {
834 JvmtiExport::oops_do(strong_roots);
835 }
836 #if INCLUDE_AOT
837 if (UseAOT && _process_strong_tasks->try_claim_task(GCH_PS_aot_oops_do)) {
838 AOTLoader::oops_do(strong_roots);
839 }
840 #endif
841 if (_process_strong_tasks->try_claim_task(GCH_PS_SystemDictionary_oops_do)) {
842 SystemDictionary::oops_do(strong_roots);
843 }
844
845 if (_process_strong_tasks->try_claim_task(GCH_PS_CodeCache_oops_do)) {
846 if (so & SO_ScavengeCodeCache) {
847 assert(code_roots != NULL, "must supply closure for code cache");
848
849 // We only visit parts of the CodeCache when scavenging.
850 ScavengableNMethods::nmethods_do(code_roots);
851 }
852 if (so & SO_AllCodeCache) {
853 assert(code_roots != NULL, "must supply closure for code cache");
854
855 // CMSCollector uses this to do intermediate-strength collections.
856 // We scan the entire code cache, since CodeCache::do_unloading is not called.
857 CodeCache::blobs_do(code_roots);
858 }
859 // Verify that the code cache contents are not subject to
860 // movement by a scavenging collection.
861 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
862 DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
863 }
864 }
865
866 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
867 OopsInGenClosure* root_closure,
868 OopsInGenClosure* old_gen_closure,
869 CLDClosure* cld_closure) {
870 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
871
872 process_roots(scope, SO_ScavengeCodeCache, root_closure,
873 cld_closure, cld_closure, &mark_code_closure);
874
875 if (_process_strong_tasks->try_claim_task(GCH_PS_younger_gens)) {
876 root_closure->reset_generation();
877 }
878
879 // When collection is parallel, all threads get to cooperate to do
880 // old generation scanning.
881 old_gen_closure->set_generation(_old_gen);
882 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
883 old_gen_closure->reset_generation();
884
885 _process_strong_tasks->all_tasks_completed(scope->n_threads());
886 }
887
888 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
889 bool is_adjust_phase,
890 ScanningOption so,
891 bool only_strong_roots,
892 OopsInGenClosure* root_closure,
893 CLDClosure* cld_closure) {
894 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
895 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
896
897 process_roots(scope, so, root_closure, cld_closure, weak_cld_closure, &mark_code_closure);
898 _process_strong_tasks->all_tasks_completed(scope->n_threads());
899 }
900
901 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
902 WeakProcessor::oops_do(root_closure);
903 _young_gen->ref_processor()->weak_oops_do(root_closure);
904 _old_gen->ref_processor()->weak_oops_do(root_closure);
905 }
906
907 bool GenCollectedHeap::no_allocs_since_save_marks() {
908 return _young_gen->no_allocs_since_save_marks() &&
909 _old_gen->no_allocs_since_save_marks();
910 }
911
912 bool GenCollectedHeap::supports_inline_contig_alloc() const {
913 return _young_gen->supports_inline_contig_alloc();
914 }
915
916 HeapWord* volatile* GenCollectedHeap::top_addr() const {
917 return _young_gen->top_addr();
918 }
919
920 HeapWord** GenCollectedHeap::end_addr() const {
921 return _young_gen->end_addr();
922 }
923
924 // public collection interfaces
925
926 void GenCollectedHeap::collect(GCCause::Cause cause) {
927 if ((cause == GCCause::_wb_young_gc) ||
928 (cause == GCCause::_gc_locker)) {
929 // Young collection for WhiteBox or GCLocker.
930 collect(cause, YoungGen);
931 } else {
932 #ifdef ASSERT
933 if (cause == GCCause::_scavenge_alot) {
934 // Young collection only.
935 collect(cause, YoungGen);
936 } else {
937 // Stop-the-world full collection.
938 collect(cause, OldGen);
939 }
940 #else
941 // Stop-the-world full collection.
942 collect(cause, OldGen);
943 #endif
944 }
945 }
946
947 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
948 // The caller doesn't have the Heap_lock
949 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
950 MutexLocker ml(Heap_lock);
951 collect_locked(cause, max_generation);
952 }
953
954 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
955 // The caller has the Heap_lock
956 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
957 collect_locked(cause, OldGen);
958 }
959
960 // this is the private collection interface
961 // The Heap_lock is expected to be held on entry.
962
963 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
964 // Read the GC count while holding the Heap_lock
965 unsigned int gc_count_before = total_collections();
966 unsigned int full_gc_count_before = total_full_collections();
967
968 if (GCLocker::should_discard(cause, gc_count_before)) {
969 return;
970 }
971
972 {
973 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
974 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
975 cause, max_generation);
976 VMThread::execute(&op);
977 }
978 }
979
980 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
981 do_full_collection(clear_all_soft_refs, OldGen);
982 }
983
984 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
985 GenerationType last_generation) {
986 do_collection(true, // full
987 clear_all_soft_refs, // clear_all_soft_refs
988 0, // size
989 false, // is_tlab
990 last_generation); // last_generation
991 // Hack XXX FIX ME !!!
992 // A scavenge may not have been attempted, or may have
993 // been attempted and failed, because the old gen was too full
994 if (gc_cause() == GCCause::_gc_locker && incremental_collection_failed()) {
995 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
996 // This time allow the old gen to be collected as well
997 do_collection(true, // full
998 clear_all_soft_refs, // clear_all_soft_refs
999 0, // size
1000 false, // is_tlab
1001 OldGen); // last_generation
1002 }
1003 }
1004
1005 bool GenCollectedHeap::is_in_young(oop p) {
1006 bool result = cast_from_oop<HeapWord*>(p) < _old_gen->reserved().start();
1007 assert(result == _young_gen->is_in_reserved(p),
1008 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
1009 return result;
1010 }
1011
1012 // Returns "TRUE" iff "p" points into the committed areas of the heap.
1013 bool GenCollectedHeap::is_in(const void* p) const {
1014 return _young_gen->is_in(p) || _old_gen->is_in(p);
1015 }
1016
1017 #ifdef ASSERT
1018 // Don't implement this by using is_in_young(). This method is used
1019 // in some cases to check that is_in_young() is correct.
1020 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
1021 assert(is_in_reserved(p) || p == NULL,
1022 "Does not work if address is non-null and outside of the heap");
1023 return p < _young_gen->reserved().end() && p != NULL;
1024 }
1025 #endif
1026
1027 void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) {
1028 _young_gen->oop_iterate(cl);
1029 _old_gen->oop_iterate(cl);
1030 }
1031
1032 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
1033 _young_gen->object_iterate(cl);
1034 _old_gen->object_iterate(cl);
1035 }
1036
1037 Space* GenCollectedHeap::space_containing(const void* addr) const {
1038 Space* res = _young_gen->space_containing(addr);
1039 if (res != NULL) {
1040 return res;
1041 }
1042 res = _old_gen->space_containing(addr);
1043 assert(res != NULL, "Could not find containing space");
1044 return res;
1045 }
1046
1047 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1048 assert(is_in_reserved(addr), "block_start of address outside of heap");
1049 if (_young_gen->is_in_reserved(addr)) {
1050 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
1051 return _young_gen->block_start(addr);
1052 }
1053
1054 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1055 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
1056 return _old_gen->block_start(addr);
1057 }
1058
1059 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1060 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1061 assert(block_start(addr) == addr, "addr must be a block start");
1062 if (_young_gen->is_in_reserved(addr)) {
1063 return _young_gen->block_is_obj(addr);
1064 }
1065
1066 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1067 return _old_gen->block_is_obj(addr);
1068 }
1069
1070 bool GenCollectedHeap::supports_tlab_allocation() const {
1071 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1072 return _young_gen->supports_tlab_allocation();
1073 }
1074
1075 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1076 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1077 if (_young_gen->supports_tlab_allocation()) {
1078 return _young_gen->tlab_capacity();
1079 }
1080 return 0;
1081 }
1082
1083 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1084 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1085 if (_young_gen->supports_tlab_allocation()) {
1086 return _young_gen->tlab_used();
1087 }
1088 return 0;
1089 }
1090
1091 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1092 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1093 if (_young_gen->supports_tlab_allocation()) {
1094 return _young_gen->unsafe_max_tlab_alloc();
1095 }
1096 return 0;
1097 }
1098
1099 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size,
1100 size_t requested_size,
1101 size_t* actual_size) {
1102 bool gc_overhead_limit_was_exceeded;
1103 HeapWord* result = mem_allocate_work(requested_size /* size */,
1104 true /* is_tlab */,
1105 &gc_overhead_limit_was_exceeded);
1106 if (result != NULL) {
1107 *actual_size = requested_size;
1108 }
1109
1110 return result;
1111 }
1112
1113 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1114 // from the list headed by "*prev_ptr".
1115 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1116 bool first = true;
1117 size_t min_size = 0; // "first" makes this conceptually infinite.
1118 ScratchBlock **smallest_ptr, *smallest;
1119 ScratchBlock *cur = *prev_ptr;
1120 while (cur) {
1121 assert(*prev_ptr == cur, "just checking");
1122 if (first || cur->num_words < min_size) {
1123 smallest_ptr = prev_ptr;
1124 smallest = cur;
1125 min_size = smallest->num_words;
1126 first = false;
1127 }
1128 prev_ptr = &cur->next;
1129 cur = cur->next;
1130 }
1131 smallest = *smallest_ptr;
1132 *smallest_ptr = smallest->next;
1133 return smallest;
1134 }
1135
1136 // Sort the scratch block list headed by res into decreasing size order,
1137 // and set "res" to the result.
1138 static void sort_scratch_list(ScratchBlock*& list) {
1139 ScratchBlock* sorted = NULL;
1140 ScratchBlock* unsorted = list;
1141 while (unsorted) {
1142 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1143 smallest->next = sorted;
1144 sorted = smallest;
1145 }
1146 list = sorted;
1147 }
1148
1149 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1150 size_t max_alloc_words) {
1151 ScratchBlock* res = NULL;
1152 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1153 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1154 sort_scratch_list(res);
1155 return res;
1156 }
1157
1158 void GenCollectedHeap::release_scratch() {
1159 _young_gen->reset_scratch();
1160 _old_gen->reset_scratch();
1161 }
1162
1163 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1164 void do_generation(Generation* gen) {
1165 gen->prepare_for_verify();
1166 }
1167 };
1168
1169 void GenCollectedHeap::prepare_for_verify() {
1170 ensure_parsability(false); // no need to retire TLABs
1171 GenPrepareForVerifyClosure blk;
1172 generation_iterate(&blk, false);
1173 }
1174
1175 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1176 bool old_to_young) {
1177 if (old_to_young) {
1178 cl->do_generation(_old_gen);
1179 cl->do_generation(_young_gen);
1180 } else {
1181 cl->do_generation(_young_gen);
1182 cl->do_generation(_old_gen);
1183 }
1184 }
1185
1186 bool GenCollectedHeap::is_maximal_no_gc() const {
1187 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1188 }
1189
1190 void GenCollectedHeap::save_marks() {
1191 _young_gen->save_marks();
1192 _old_gen->save_marks();
1193 }
1194
1195 GenCollectedHeap* GenCollectedHeap::heap() {
1196 CollectedHeap* heap = Universe::heap();
1197 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1198 assert(heap->kind() == CollectedHeap::Serial, "Invalid name");
1199 return (GenCollectedHeap*) heap;
1200 }
1201
1202 #if INCLUDE_SERIALGC
1203 void GenCollectedHeap::prepare_for_compaction() {
1204 // Start by compacting into same gen.
1205 CompactPoint cp(_old_gen);
1206 _old_gen->prepare_for_compaction(&cp);
1207 _young_gen->prepare_for_compaction(&cp);
1208 }
1209 #endif // INCLUDE_SERIALGC
1210
1211 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1212 log_debug(gc, verify)("%s", _old_gen->name());
1213 _old_gen->verify();
1214
1215 log_debug(gc, verify)("%s", _old_gen->name());
1216 _young_gen->verify();
1217
1218 log_debug(gc, verify)("RemSet");
1219 rem_set()->verify();
1220 }
1221
1222 void GenCollectedHeap::print_on(outputStream* st) const {
1223 _young_gen->print_on(st);
1224 _old_gen->print_on(st);
1225 MetaspaceUtils::print_on(st);
1226 }
1227
1228 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1229 }
1230
1231 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1232 }
1233
1234 bool GenCollectedHeap::print_location(outputStream* st, void* addr) const {
1235 return BlockLocationPrinter<GenCollectedHeap>::print_location(st, addr);
1236 }
1237
1238 void GenCollectedHeap::print_tracing_info() const {
1239 if (log_is_enabled(Debug, gc, heap, exit)) {
1240 LogStreamHandle(Debug, gc, heap, exit) lsh;
1241 _young_gen->print_summary_info_on(&lsh);
1242 _old_gen->print_summary_info_on(&lsh);
1243 }
1244 }
1245
1246 void GenCollectedHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const {
1247 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen();
1248
1249 log_info(gc, heap)(HEAP_CHANGE_FORMAT" "
1250 HEAP_CHANGE_FORMAT" "
1251 HEAP_CHANGE_FORMAT,
1252 HEAP_CHANGE_FORMAT_ARGS(def_new_gen->short_name(),
1253 pre_gc_values.young_gen_used(),
1254 pre_gc_values.young_gen_capacity(),
1255 def_new_gen->used(),
1256 def_new_gen->capacity()),
1257 HEAP_CHANGE_FORMAT_ARGS("Eden",
1258 pre_gc_values.eden_used(),
1259 pre_gc_values.eden_capacity(),
1260 def_new_gen->eden()->used(),
1261 def_new_gen->eden()->capacity()),
1262 HEAP_CHANGE_FORMAT_ARGS("From",
1263 pre_gc_values.from_used(),
1264 pre_gc_values.from_capacity(),
1265 def_new_gen->from()->used(),
1266 def_new_gen->from()->capacity()));
1267 log_info(gc, heap)(HEAP_CHANGE_FORMAT,
1268 HEAP_CHANGE_FORMAT_ARGS(old_gen()->short_name(),
1269 pre_gc_values.old_gen_used(),
1270 pre_gc_values.old_gen_capacity(),
1271 old_gen()->used(),
1272 old_gen()->capacity()));
1273 MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes());
1274 }
1275
1276 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1277 private:
1278 bool _full;
1279 public:
1280 void do_generation(Generation* gen) {
1281 gen->gc_prologue(_full);
1282 }
1283 GenGCPrologueClosure(bool full) : _full(full) {};
1284 };
1285
1286 void GenCollectedHeap::gc_prologue(bool full) {
1287 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1288
1289 // Fill TLAB's and such
1290 ensure_parsability(true); // retire TLABs
1291
1292 // Walk generations
1293 GenGCPrologueClosure blk(full);
1294 generation_iterate(&blk, false); // not old-to-young.
1295 };
1296
1297 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1298 private:
1299 bool _full;
1300 public:
1301 void do_generation(Generation* gen) {
1302 gen->gc_epilogue(_full);
1303 }
1304 GenGCEpilogueClosure(bool full) : _full(full) {};
1305 };
1306
1307 void GenCollectedHeap::gc_epilogue(bool full) {
1308 #if COMPILER2_OR_JVMCI
1309 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1310 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1311 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1312 #endif // COMPILER2_OR_JVMCI
1313
1314 resize_all_tlabs();
1315
1316 GenGCEpilogueClosure blk(full);
1317 generation_iterate(&blk, false); // not old-to-young.
1318
1319 if (!CleanChunkPoolAsync) {
1320 Chunk::clean_chunk_pool();
1321 }
1322
1323 MetaspaceCounters::update_performance_counters();
1324 CompressedClassSpaceCounters::update_performance_counters();
1325 };
1326
1327 #ifndef PRODUCT
1328 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1329 private:
1330 public:
1331 void do_generation(Generation* gen) {
1332 gen->record_spaces_top();
1333 }
1334 };
1335
1336 void GenCollectedHeap::record_gen_tops_before_GC() {
1337 if (ZapUnusedHeapArea) {
1338 GenGCSaveTopsBeforeGCClosure blk;
1339 generation_iterate(&blk, false); // not old-to-young.
1340 }
1341 }
1342 #endif // not PRODUCT
1343
1344 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1345 public:
1346 void do_generation(Generation* gen) {
1347 gen->ensure_parsability();
1348 }
1349 };
1350
1351 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1352 CollectedHeap::ensure_parsability(retire_tlabs);
1353 GenEnsureParsabilityClosure ep_cl;
1354 generation_iterate(&ep_cl, false);
1355 }
1356
1357 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1358 oop obj,
1359 size_t obj_size) {
1360 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1361 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1362 HeapWord* result = NULL;
1363
1364 result = old_gen->expand_and_allocate(obj_size, false);
1365
1366 if (result != NULL) {
1367 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), result, obj_size);
1368 }
1369 return oop(result);
1370 }
1371
1372 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1373 jlong _time; // in ms
1374 jlong _now; // in ms
1375
1376 public:
1377 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1378
1379 jlong time() { return _time; }
1380
1381 void do_generation(Generation* gen) {
1382 _time = MIN2(_time, gen->time_of_last_gc(_now));
1383 }
1384 };
1385
1386 jlong GenCollectedHeap::millis_since_last_gc() {
1387 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1388 // provided the underlying platform provides such a time source
1389 // (and it is bug free). So we still have to guard against getting
1390 // back a time later than 'now'.
1391 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1392 GenTimeOfLastGCClosure tolgc_cl(now);
1393 // iterate over generations getting the oldest
1394 // time that a generation was collected
1395 generation_iterate(&tolgc_cl, false);
1396
1397 jlong retVal = now - tolgc_cl.time();
1398 if (retVal < 0) {
1399 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1400 ". returning zero instead.", retVal);
1401 return 0;
1402 }
1403 return retVal;
1404 }