1 /*
2 * Copyright (c) 2000, 2018, 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/symbolTable.hpp"
28 #include "classfile/stringTable.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "gc/shared/cardTableRS.hpp"
34 #include "gc/shared/collectedHeap.inline.hpp"
35 #include "gc/shared/collectorCounters.hpp"
36 #include "gc/shared/gcId.hpp"
37 #include "gc/shared/gcLocker.inline.hpp"
38 #include "gc/shared/gcTrace.hpp"
39 #include "gc/shared/gcTraceTime.inline.hpp"
40 #include "gc/shared/genCollectedHeap.hpp"
41 #include "gc/shared/genOopClosures.inline.hpp"
42 #include "gc/shared/generationSpec.hpp"
43 #include "gc/shared/space.hpp"
44 #include "gc/shared/strongRootsScope.hpp"
45 #include "gc/shared/vmGCOperations.hpp"
46 #include "gc/shared/weakProcessor.hpp"
47 #include "gc/shared/workgroup.hpp"
48 #include "memory/filemap.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "runtime/biasedLocking.hpp"
52 #include "runtime/handles.hpp"
53 #include "runtime/handles.inline.hpp"
54 #include "runtime/java.hpp"
55 #include "runtime/vmThread.hpp"
56 #include "services/management.hpp"
57 #include "services/memoryService.hpp"
58 #include "utilities/debug.hpp"
59 #include "utilities/formatBuffer.hpp"
60 #include "utilities/macros.hpp"
61 #include "utilities/stack.inline.hpp"
62 #include "utilities/vmError.hpp"
63
64 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
65 CollectedHeap(),
66 _rem_set(NULL),
67 _gen_policy(policy),
68 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
69 _full_collections_completed(0)
70 {
71 assert(policy != NULL, "Sanity check");
72 }
73
74 jint GenCollectedHeap::initialize() {
75 // While there are no constraints in the GC code that HeapWordSize
76 // be any particular value, there are multiple other areas in the
77 // system which believe this to be true (e.g. oop->object_size in some
78 // cases incorrectly returns the size in wordSize units rather than
79 // HeapWordSize).
80 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
81
82 // Allocate space for the heap.
83
84 char* heap_address;
85 ReservedSpace heap_rs;
86
87 size_t heap_alignment = collector_policy()->heap_alignment();
88
89 heap_address = allocate(heap_alignment, &heap_rs);
90
91 if (!heap_rs.is_reserved()) {
92 vm_shutdown_during_initialization(
93 "Could not reserve enough space for object heap");
94 return JNI_ENOMEM;
95 }
96
97 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
98
99 _rem_set = new CardTableRS(reserved_region());
100 set_barrier_set(rem_set()->bs());
101
102 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false);
103 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, rem_set());
104 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size());
105
106 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false);
107 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, rem_set());
108 clear_incremental_collection_failed();
109
110 return JNI_OK;
111 }
112
113 char* GenCollectedHeap::allocate(size_t alignment,
114 ReservedSpace* heap_rs){
115 // Now figure out the total size.
116 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size();
117 assert(alignment % pageSize == 0, "Must be");
118
119 GenerationSpec* young_spec = gen_policy()->young_gen_spec();
120 GenerationSpec* old_spec = gen_policy()->old_gen_spec();
121
122 // Check for overflow.
123 size_t total_reserved = young_spec->max_size() + old_spec->max_size();
124 if (total_reserved < young_spec->max_size()) {
125 vm_exit_during_initialization("The size of the object heap + VM data exceeds "
126 "the maximum representable size");
127 }
128 assert(total_reserved % alignment == 0,
129 "Gen size; total_reserved=" SIZE_FORMAT ", alignment="
130 SIZE_FORMAT, total_reserved, alignment);
131
132 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
133
134 os::trace_page_sizes("Heap",
135 collector_policy()->min_heap_byte_size(),
136 total_reserved,
137 alignment,
138 heap_rs->base(),
139 heap_rs->size());
140
141 return heap_rs->base();
142 }
143
144 void GenCollectedHeap::post_initialize() {
145 CollectedHeap::post_initialize();
146 ref_processing_init();
147 check_gen_kinds();
148 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen;
149
150 _gen_policy->initialize_size_policy(def_new_gen->eden()->capacity(),
151 _old_gen->capacity(),
152 def_new_gen->from()->capacity());
153
154 // Connect the two policies.
155 _soft_ref_gen_policy.set_size_policy(_gen_policy->size_policy());
156
157 _gen_policy->initialize_gc_policy_counters();
158 }
159
160 void GenCollectedHeap::ref_processing_init() {
161 _young_gen->ref_processor_init();
162 _old_gen->ref_processor_init();
163 }
164
165 size_t GenCollectedHeap::capacity() const {
166 return _young_gen->capacity() + _old_gen->capacity();
167 }
168
169 size_t GenCollectedHeap::used() const {
170 return _young_gen->used() + _old_gen->used();
171 }
172
173 void GenCollectedHeap::save_used_regions() {
174 _old_gen->save_used_region();
175 _young_gen->save_used_region();
176 }
177
178 size_t GenCollectedHeap::max_capacity() const {
179 return _young_gen->max_capacity() + _old_gen->max_capacity();
180 }
181
182 // Update the _full_collections_completed counter
183 // at the end of a stop-world full GC.
184 unsigned int GenCollectedHeap::update_full_collections_completed() {
185 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
186 assert(_full_collections_completed <= _total_full_collections,
187 "Can't complete more collections than were started");
188 _full_collections_completed = _total_full_collections;
189 ml.notify_all();
190 return _full_collections_completed;
191 }
192
193 // Update the _full_collections_completed counter, as appropriate,
194 // at the end of a concurrent GC cycle. Note the conditional update
195 // below to allow this method to be called by a concurrent collector
196 // without synchronizing in any manner with the VM thread (which
197 // may already have initiated a STW full collection "concurrently").
198 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
199 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
200 assert((_full_collections_completed <= _total_full_collections) &&
201 (count <= _total_full_collections),
202 "Can't complete more collections than were started");
203 if (count > _full_collections_completed) {
204 _full_collections_completed = count;
205 ml.notify_all();
206 }
207 return _full_collections_completed;
208 }
209
210 // Return true if any of the following is true:
211 // . the allocation won't fit into the current young gen heap
212 // . gc locker is occupied (jni critical section)
213 // . heap memory is tight -- the most recent previous collection
214 // was a full collection because a partial collection (would
215 // have) failed and is likely to fail again
216 bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const {
217 size_t young_capacity = young_gen()->capacity_before_gc();
218 return (word_size > heap_word_size(young_capacity))
219 || GCLocker::is_active_and_needs_gc()
220 || incremental_collection_failed();
221 }
222
223 HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) {
224 HeapWord* result = NULL;
225 if (old_gen()->should_allocate(size, is_tlab)) {
226 result = old_gen()->expand_and_allocate(size, is_tlab);
227 }
228 if (result == NULL) {
229 if (young_gen()->should_allocate(size, is_tlab)) {
230 result = young_gen()->expand_and_allocate(size, is_tlab);
231 }
232 }
233 assert(result == NULL || is_in_reserved(result), "result not in heap");
234 return result;
235 }
236
237 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size,
238 bool is_tlab,
239 bool* gc_overhead_limit_was_exceeded) {
240 debug_only(check_for_valid_allocation_state());
241 assert(no_gc_in_progress(), "Allocation during gc not allowed");
242
243 // In general gc_overhead_limit_was_exceeded should be false so
244 // set it so here and reset it to true only if the gc time
245 // limit is being exceeded as checked below.
246 *gc_overhead_limit_was_exceeded = false;
247
248 HeapWord* result = NULL;
249
250 // Loop until the allocation is satisfied, or unsatisfied after GC.
251 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
252 HandleMark hm; // Discard any handles allocated in each iteration.
253
254 // First allocation attempt is lock-free.
255 Generation *young = young_gen();
256 assert(young->supports_inline_contig_alloc(),
257 "Otherwise, must do alloc within heap lock");
258 if (young->should_allocate(size, is_tlab)) {
259 result = young->par_allocate(size, is_tlab);
260 if (result != NULL) {
261 assert(is_in_reserved(result), "result not in heap");
262 return result;
263 }
264 }
265 uint gc_count_before; // Read inside the Heap_lock locked region.
266 {
267 MutexLocker ml(Heap_lock);
268 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation");
269 // Note that only large objects get a shot at being
270 // allocated in later generations.
271 bool first_only = ! should_try_older_generation_allocation(size);
272
273 result = attempt_allocation(size, is_tlab, first_only);
274 if (result != NULL) {
275 assert(is_in_reserved(result), "result not in heap");
276 return result;
277 }
278
279 if (GCLocker::is_active_and_needs_gc()) {
280 if (is_tlab) {
281 return NULL; // Caller will retry allocating individual object.
282 }
283 if (!is_maximal_no_gc()) {
284 // Try and expand heap to satisfy request.
285 result = expand_heap_and_allocate(size, is_tlab);
286 // Result could be null if we are out of space.
287 if (result != NULL) {
288 return result;
289 }
290 }
291
292 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
293 return NULL; // We didn't get to do a GC and we didn't get any memory.
294 }
295
296 // If this thread is not in a jni critical section, we stall
297 // the requestor until the critical section has cleared and
298 // GC allowed. When the critical section clears, a GC is
299 // initiated by the last thread exiting the critical section; so
300 // we retry the allocation sequence from the beginning of the loop,
301 // rather than causing more, now probably unnecessary, GC attempts.
302 JavaThread* jthr = JavaThread::current();
303 if (!jthr->in_critical()) {
304 MutexUnlocker mul(Heap_lock);
305 // Wait for JNI critical section to be exited
306 GCLocker::stall_until_clear();
307 gclocker_stalled_count += 1;
308 continue;
309 } else {
310 if (CheckJNICalls) {
311 fatal("Possible deadlock due to allocating while"
312 " in jni critical section");
313 }
314 return NULL;
315 }
316 }
317
318 // Read the gc count while the heap lock is held.
319 gc_count_before = total_collections();
320 }
321
322 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
323 VMThread::execute(&op);
324 if (op.prologue_succeeded()) {
325 result = op.result();
326 if (op.gc_locked()) {
327 assert(result == NULL, "must be NULL if gc_locked() is true");
328 continue; // Retry and/or stall as necessary.
329 }
330
331 // Allocation has failed and a collection
332 // has been done. If the gc time limit was exceeded the
333 // this time, return NULL so that an out-of-memory
334 // will be thrown. Clear gc_overhead_limit_exceeded
335 // so that the overhead exceeded does not persist.
336
337 const bool limit_exceeded = gen_policy()->size_policy()->gc_overhead_limit_exceeded();
338 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear();
339
340 if (limit_exceeded && softrefs_clear) {
341 *gc_overhead_limit_was_exceeded = true;
342 gen_policy()->size_policy()->set_gc_overhead_limit_exceeded(false);
343 if (op.result() != NULL) {
344 CollectedHeap::fill_with_object(op.result(), size);
345 }
346 return NULL;
347 }
348 assert(result == NULL || is_in_reserved(result),
349 "result not in heap");
350 return result;
351 }
352
353 // Give a warning if we seem to be looping forever.
354 if ((QueuedAllocationWarningCount > 0) &&
355 (try_count % QueuedAllocationWarningCount == 0)) {
356 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times,"
357 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : "");
358 }
359 }
360 }
361
362 #ifndef PRODUCT
363 // Override of memory state checking method in CollectedHeap:
364 // Some collectors (CMS for example) can't have badHeapWordVal written
365 // in the first two words of an object. (For instance , in the case of
366 // CMS these words hold state used to synchronize between certain
367 // (concurrent) GC steps and direct allocating mutators.)
368 // The skip_header_HeapWords() method below, allows us to skip
369 // over the requisite number of HeapWord's. Note that (for
370 // generational collectors) this means that those many words are
371 // skipped in each object, irrespective of the generation in which
372 // that object lives. The resultant loss of precision seems to be
373 // harmless and the pain of avoiding that imprecision appears somewhat
374 // higher than we are prepared to pay for such rudimentary debugging
375 // support.
376 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
377 size_t size) {
378 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
379 // We are asked to check a size in HeapWords,
380 // but the memory is mangled in juint words.
381 juint* start = (juint*) (addr + skip_header_HeapWords());
382 juint* end = (juint*) (addr + size);
383 for (juint* slot = start; slot < end; slot += 1) {
384 assert(*slot == badHeapWordVal,
385 "Found non badHeapWordValue in pre-allocation check");
386 }
387 }
388 }
389 #endif
390
391 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
392 bool is_tlab,
393 bool first_only) {
394 HeapWord* res = NULL;
395
396 if (_young_gen->should_allocate(size, is_tlab)) {
397 res = _young_gen->allocate(size, is_tlab);
398 if (res != NULL || first_only) {
399 return res;
400 }
401 }
402
403 if (_old_gen->should_allocate(size, is_tlab)) {
404 res = _old_gen->allocate(size, is_tlab);
405 }
406
407 return res;
408 }
409
410 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
411 bool* gc_overhead_limit_was_exceeded) {
412 return mem_allocate_work(size,
413 false /* is_tlab */,
414 gc_overhead_limit_was_exceeded);
415 }
416
417 bool GenCollectedHeap::must_clear_all_soft_refs() {
418 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs ||
419 _gc_cause == GCCause::_wb_full_gc;
420 }
421
422 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size,
423 bool is_tlab, bool run_verification, bool clear_soft_refs,
424 bool restore_marks_for_biased_locking) {
425 FormatBuffer<> title("Collect gen: %s", gen->short_name());
426 GCTraceTime(Trace, gc, phases) t1(title);
427 TraceCollectorStats tcs(gen->counters());
428 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause());
429
430 gen->stat_record()->invocations++;
431 gen->stat_record()->accumulated_time.start();
432
433 // Must be done anew before each collection because
434 // a previous collection will do mangling and will
435 // change top of some spaces.
436 record_gen_tops_before_GC();
437
438 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize);
439
440 if (run_verification && VerifyBeforeGC) {
441 HandleMark hm; // Discard invalid handles created during verification
442 Universe::verify("Before GC");
443 }
444 COMPILER2_PRESENT(DerivedPointerTable::clear());
445
446 if (restore_marks_for_biased_locking) {
447 // We perform this mark word preservation work lazily
448 // because it's only at this point that we know whether we
449 // absolutely have to do it; we want to avoid doing it for
450 // scavenge-only collections where it's unnecessary
451 BiasedLocking::preserve_marks();
452 }
453
454 // Do collection work
455 {
456 // Note on ref discovery: For what appear to be historical reasons,
457 // GCH enables and disabled (by enqueing) refs discovery.
458 // In the future this should be moved into the generation's
459 // collect method so that ref discovery and enqueueing concerns
460 // are local to a generation. The collect method could return
461 // an appropriate indication in the case that notification on
462 // the ref lock was needed. This will make the treatment of
463 // weak refs more uniform (and indeed remove such concerns
464 // from GCH). XXX
465
466 HandleMark hm; // Discard invalid handles created during gc
467 save_marks(); // save marks for all gens
468 // We want to discover references, but not process them yet.
469 // This mode is disabled in process_discovered_references if the
470 // generation does some collection work, or in
471 // enqueue_discovered_references if the generation returns
472 // without doing any work.
473 ReferenceProcessor* rp = gen->ref_processor();
474 // If the discovery of ("weak") refs in this generation is
475 // atomic wrt other collectors in this configuration, we
476 // are guaranteed to have empty discovered ref lists.
477 if (rp->discovery_is_atomic()) {
478 rp->enable_discovery();
479 rp->setup_policy(clear_soft_refs);
480 } else {
481 // collect() below will enable discovery as appropriate
482 }
483 gen->collect(full, clear_soft_refs, size, is_tlab);
484 if (!rp->enqueuing_is_done()) {
485 ReferenceProcessorPhaseTimes pt(NULL, rp->num_q());
486 rp->enqueue_discovered_references(NULL, &pt);
487 pt.print_enqueue_phase();
488 } else {
489 rp->set_enqueuing_is_done(false);
490 }
491 rp->verify_no_references_recorded();
492 }
493
494 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
495
496 gen->stat_record()->accumulated_time.stop();
497
498 update_gc_stats(gen, full);
499
500 if (run_verification && VerifyAfterGC) {
501 HandleMark hm; // Discard invalid handles created during verification
502 Universe::verify("After GC");
503 }
504 }
505
506 void GenCollectedHeap::do_collection(bool full,
507 bool clear_all_soft_refs,
508 size_t size,
509 bool is_tlab,
510 GenerationType max_generation) {
511 ResourceMark rm;
512 DEBUG_ONLY(Thread* my_thread = Thread::current();)
513
514 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
515 assert(my_thread->is_VM_thread() ||
516 my_thread->is_ConcurrentGC_thread(),
517 "incorrect thread type capability");
518 assert(Heap_lock->is_locked(),
519 "the requesting thread should have the Heap_lock");
520 guarantee(!is_gc_active(), "collection is not reentrant");
521
522 if (GCLocker::check_active_before_gc()) {
523 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
524 }
525
526 GCIdMark gc_id_mark;
527
528 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
529 soft_ref_policy()->should_clear_all_soft_refs();
530
531 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy());
532
533 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
534
535 print_heap_before_gc();
536
537 {
538 FlagSetting fl(_is_gc_active, true);
539
540 bool complete = full && (max_generation == OldGen);
541 bool old_collects_young = complete && !ScavengeBeforeFullGC;
542 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
543
544 FormatBuffer<> gc_string("%s", "Pause ");
545 if (do_young_collection) {
546 gc_string.append("Young");
547 } else {
548 gc_string.append("Full");
549 }
550
551 GCTraceCPUTime tcpu;
552 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true);
553
554 gc_prologue(complete);
555 increment_total_collections(complete);
556
557 size_t young_prev_used = _young_gen->used();
558 size_t old_prev_used = _old_gen->used();
559
560 bool run_verification = total_collections() >= VerifyGCStartAt;
561
562 bool prepared_for_verification = false;
563 bool collected_old = false;
564
565 if (do_young_collection) {
566 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
567 prepare_for_verify();
568 prepared_for_verification = true;
569 }
570
571 collect_generation(_young_gen,
572 full,
573 size,
574 is_tlab,
575 run_verification && VerifyGCLevel <= 0,
576 do_clear_all_soft_refs,
577 false);
578
579 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
580 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
581 // Allocation request was met by young GC.
582 size = 0;
583 }
584 }
585
586 bool must_restore_marks_for_biased_locking = false;
587
588 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) {
589 if (!complete) {
590 // The full_collections increment was missed above.
591 increment_total_full_collections();
592 }
593
594 if (!prepared_for_verification && run_verification &&
595 VerifyGCLevel <= 1 && VerifyBeforeGC) {
596 prepare_for_verify();
597 }
598
599 if (do_young_collection) {
600 // We did a young GC. Need a new GC id for the old GC.
601 GCIdMark gc_id_mark;
602 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
603 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
604 } else {
605 // No young GC done. Use the same GC id as was set up earlier in this method.
606 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
607 }
608
609 must_restore_marks_for_biased_locking = true;
610 collected_old = true;
611 }
612
613 // Update "complete" boolean wrt what actually transpired --
614 // for instance, a promotion failure could have led to
615 // a whole heap collection.
616 complete = complete || collected_old;
617
618 print_heap_change(young_prev_used, old_prev_used);
619 MetaspaceAux::print_metaspace_change(metadata_prev_used);
620
621 // Adjust generation sizes.
622 if (collected_old) {
623 _old_gen->compute_new_size();
624 }
625 _young_gen->compute_new_size();
626
627 if (complete) {
628 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
629 ClassLoaderDataGraph::purge();
630 MetaspaceAux::verify_metrics();
631 // Resize the metaspace capacity after full collections
632 MetaspaceGC::compute_new_size();
633 update_full_collections_completed();
634 }
635
636 // Track memory usage and detect low memory after GC finishes
637 MemoryService::track_memory_usage();
638
639 gc_epilogue(complete);
640
641 if (must_restore_marks_for_biased_locking) {
642 BiasedLocking::restore_marks();
643 }
644 }
645
646 print_heap_after_gc();
647
648 #ifdef TRACESPINNING
649 ParallelTaskTerminator::print_termination_counts();
650 #endif
651 }
652
653 void GenCollectedHeap::register_nmethod(nmethod* nm) {
654 CodeCache::register_scavenge_root_nmethod(nm);
655 }
656
657 void GenCollectedHeap::verify_nmethod(nmethod* nm) {
658 CodeCache::verify_scavenge_root_nmethod(nm);
659 }
660
661 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
662 GCCauseSetter x(this, GCCause::_allocation_failure);
663 HeapWord* result = NULL;
664
665 assert(size != 0, "Precondition violated");
666 if (GCLocker::is_active_and_needs_gc()) {
667 // GC locker is active; instead of a collection we will attempt
668 // to expand the heap, if there's room for expansion.
669 if (!is_maximal_no_gc()) {
670 result = expand_heap_and_allocate(size, is_tlab);
671 }
672 return result; // Could be null if we are out of space.
673 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) {
674 // Do an incremental collection.
675 do_collection(false, // full
676 false, // clear_all_soft_refs
677 size, // size
678 is_tlab, // is_tlab
679 GenCollectedHeap::OldGen); // max_generation
680 } else {
681 log_trace(gc)(" :: Trying full because partial may fail :: ");
682 // Try a full collection; see delta for bug id 6266275
683 // for the original code and why this has been simplified
684 // with from-space allocation criteria modified and
685 // such allocation moved out of the safepoint path.
686 do_collection(true, // full
687 false, // clear_all_soft_refs
688 size, // size
689 is_tlab, // is_tlab
690 GenCollectedHeap::OldGen); // max_generation
691 }
692
693 result = attempt_allocation(size, is_tlab, false /*first_only*/);
694
695 if (result != NULL) {
696 assert(is_in_reserved(result), "result not in heap");
697 return result;
698 }
699
700 // OK, collection failed, try expansion.
701 result = expand_heap_and_allocate(size, is_tlab);
702 if (result != NULL) {
703 return result;
704 }
705
706 // If we reach this point, we're really out of memory. Try every trick
707 // we can to reclaim memory. Force collection of soft references. Force
708 // a complete compaction of the heap. Any additional methods for finding
709 // free memory should be here, especially if they are expensive. If this
710 // attempt fails, an OOM exception will be thrown.
711 {
712 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
713
714 do_collection(true, // full
715 true, // clear_all_soft_refs
716 size, // size
717 is_tlab, // is_tlab
718 GenCollectedHeap::OldGen); // max_generation
719 }
720
721 result = attempt_allocation(size, is_tlab, false /* first_only */);
722 if (result != NULL) {
723 assert(is_in_reserved(result), "result not in heap");
724 return result;
725 }
726
727 assert(!soft_ref_policy()->should_clear_all_soft_refs(),
728 "Flag should have been handled and cleared prior to this point");
729
730 // What else? We might try synchronous finalization later. If the total
731 // space available is large enough for the allocation, then a more
732 // complete compaction phase than we've tried so far might be
733 // appropriate.
734 return NULL;
735 }
736
737 #ifdef ASSERT
738 class AssertNonScavengableClosure: public OopClosure {
739 public:
740 virtual void do_oop(oop* p) {
741 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p),
742 "Referent should not be scavengable."); }
743 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
744 };
745 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
746 #endif
747
748 void GenCollectedHeap::process_roots(StrongRootsScope* scope,
749 ScanningOption so,
750 OopClosure* strong_roots,
751 OopClosure* weak_roots,
752 CLDClosure* strong_cld_closure,
753 CLDClosure* weak_cld_closure,
754 CodeBlobToOopClosure* code_roots) {
755 // General roots.
756 assert(Threads::thread_claim_parity() != 0, "must have called prologue code");
757 assert(code_roots != NULL, "code root closure should always be set");
758 // _n_termination for _process_strong_tasks should be set up stream
759 // in a method not running in a GC worker. Otherwise the GC worker
760 // could be trying to change the termination condition while the task
761 // is executing in another GC worker.
762
763 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
764 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
765 }
766
767 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
768 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
769
770 bool is_par = scope->n_threads() > 1;
771 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p);
772
773 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
774 Universe::oops_do(strong_roots);
775 }
776 // Global (strong) JNI handles
777 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
778 JNIHandles::oops_do(strong_roots);
779 }
780
781 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
782 ObjectSynchronizer::oops_do(strong_roots);
783 }
784 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
785 Management::oops_do(strong_roots);
786 }
787 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
788 JvmtiExport::oops_do(strong_roots);
789 }
790 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) {
791 AOTLoader::oops_do(strong_roots);
792 }
793
794 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
795 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
796 }
797
798 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
799 if (so & SO_ScavengeCodeCache) {
800 assert(code_roots != NULL, "must supply closure for code cache");
801
802 // We only visit parts of the CodeCache when scavenging.
803 CodeCache::scavenge_root_nmethods_do(code_roots);
804 }
805 if (so & SO_AllCodeCache) {
806 assert(code_roots != NULL, "must supply closure for code cache");
807
808 // CMSCollector uses this to do intermediate-strength collections.
809 // We scan the entire code cache, since CodeCache::do_unloading is not called.
810 CodeCache::blobs_do(code_roots);
811 }
812 // Verify that the code cache contents are not subject to
813 // movement by a scavenging collection.
814 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
815 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
816 }
817 }
818
819 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope,
820 OopClosure* root_closure) {
821 assert(root_closure != NULL, "Must be set");
822 // All threads execute the following. A specific chunk of buckets
823 // from the StringTable are the individual tasks.
824 if (scope->n_threads() > 1) {
825 StringTable::possibly_parallel_oops_do(root_closure);
826 } else {
827 StringTable::oops_do(root_closure);
828 }
829 }
830
831 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope,
832 OopsInGenClosure* root_closure,
833 OopsInGenClosure* old_gen_closure,
834 CLDClosure* cld_closure) {
835 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations);
836
837 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure,
838 cld_closure, cld_closure, &mark_code_closure);
839 process_string_table_roots(scope, root_closure);
840
841 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
842 root_closure->reset_generation();
843 }
844
845 // When collection is parallel, all threads get to cooperate to do
846 // old generation scanning.
847 old_gen_closure->set_generation(_old_gen);
848 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads());
849 old_gen_closure->reset_generation();
850
851 _process_strong_tasks->all_tasks_completed(scope->n_threads());
852 }
853
854 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope,
855 bool is_adjust_phase,
856 ScanningOption so,
857 bool only_strong_roots,
858 OopsInGenClosure* root_closure,
859 CLDClosure* cld_closure) {
860 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase);
861 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure;
862 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
863
864 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure);
865 if (is_adjust_phase) {
866 // We never treat the string table as roots during marking
867 // for the full gc, so we only need to process it during
868 // the adjust phase.
869 process_string_table_roots(scope, root_closure);
870 }
871
872 _process_strong_tasks->all_tasks_completed(scope->n_threads());
873 }
874
875 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
876 WeakProcessor::oops_do(root_closure);
877 _young_gen->ref_processor()->weak_oops_do(root_closure);
878 _old_gen->ref_processor()->weak_oops_do(root_closure);
879 }
880
881 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
882 void GenCollectedHeap:: \
883 oop_since_save_marks_iterate(GenerationType gen, \
884 OopClosureType* cur, \
885 OopClosureType* older) { \
886 if (gen == YoungGen) { \
887 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
888 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \
889 } else { \
890 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \
891 } \
892 }
893
894 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
895
896 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
897
898 bool GenCollectedHeap::no_allocs_since_save_marks() {
899 return _young_gen->no_allocs_since_save_marks() &&
900 _old_gen->no_allocs_since_save_marks();
901 }
902
903 bool GenCollectedHeap::supports_inline_contig_alloc() const {
904 return _young_gen->supports_inline_contig_alloc();
905 }
906
907 HeapWord* volatile* GenCollectedHeap::top_addr() const {
908 return _young_gen->top_addr();
909 }
910
911 HeapWord** GenCollectedHeap::end_addr() const {
912 return _young_gen->end_addr();
913 }
914
915 // public collection interfaces
916
917 void GenCollectedHeap::collect(GCCause::Cause cause) {
918 if (cause == GCCause::_wb_young_gc) {
919 // Young collection for the WhiteBox API.
920 collect(cause, YoungGen);
921 } else {
922 #ifdef ASSERT
923 if (cause == GCCause::_scavenge_alot) {
924 // Young collection only.
925 collect(cause, YoungGen);
926 } else {
927 // Stop-the-world full collection.
928 collect(cause, OldGen);
929 }
930 #else
931 // Stop-the-world full collection.
932 collect(cause, OldGen);
933 #endif
934 }
935 }
936
937 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) {
938 // The caller doesn't have the Heap_lock
939 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
940 MutexLocker ml(Heap_lock);
941 collect_locked(cause, max_generation);
942 }
943
944 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
945 // The caller has the Heap_lock
946 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
947 collect_locked(cause, OldGen);
948 }
949
950 // this is the private collection interface
951 // The Heap_lock is expected to be held on entry.
952
953 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) {
954 // Read the GC count while holding the Heap_lock
955 unsigned int gc_count_before = total_collections();
956 unsigned int full_gc_count_before = total_full_collections();
957 {
958 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
959 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
960 cause, max_generation);
961 VMThread::execute(&op);
962 }
963 }
964
965 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
966 do_full_collection(clear_all_soft_refs, OldGen);
967 }
968
969 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
970 GenerationType last_generation) {
971 GenerationType local_last_generation;
972 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
973 gc_cause() == GCCause::_gc_locker) {
974 local_last_generation = YoungGen;
975 } else {
976 local_last_generation = last_generation;
977 }
978
979 do_collection(true, // full
980 clear_all_soft_refs, // clear_all_soft_refs
981 0, // size
982 false, // is_tlab
983 local_last_generation); // last_generation
984 // Hack XXX FIX ME !!!
985 // A scavenge may not have been attempted, or may have
986 // been attempted and failed, because the old gen was too full
987 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker &&
988 incremental_collection_will_fail(false /* don't consult_young */)) {
989 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed");
990 // This time allow the old gen to be collected as well
991 do_collection(true, // full
992 clear_all_soft_refs, // clear_all_soft_refs
993 0, // size
994 false, // is_tlab
995 OldGen); // last_generation
996 }
997 }
998
999 bool GenCollectedHeap::is_in_young(oop p) {
1000 bool result = ((HeapWord*)p) < _old_gen->reserved().start();
1001 assert(result == _young_gen->is_in_reserved(p),
1002 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p));
1003 return result;
1004 }
1005
1006 // Returns "TRUE" iff "p" points into the committed areas of the heap.
1007 bool GenCollectedHeap::is_in(const void* p) const {
1008 return _young_gen->is_in(p) || _old_gen->is_in(p);
1009 }
1010
1011 #ifdef ASSERT
1012 // Don't implement this by using is_in_young(). This method is used
1013 // in some cases to check that is_in_young() is correct.
1014 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
1015 assert(is_in_reserved(p) || p == NULL,
1016 "Does not work if address is non-null and outside of the heap");
1017 return p < _young_gen->reserved().end() && p != NULL;
1018 }
1019 #endif
1020
1021 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) {
1022 NoHeaderExtendedOopClosure no_header_cl(cl);
1023 oop_iterate(&no_header_cl);
1024 }
1025
1026 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
1027 _young_gen->oop_iterate(cl);
1028 _old_gen->oop_iterate(cl);
1029 }
1030
1031 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
1032 _young_gen->object_iterate(cl);
1033 _old_gen->object_iterate(cl);
1034 }
1035
1036 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
1037 _young_gen->safe_object_iterate(cl);
1038 _old_gen->safe_object_iterate(cl);
1039 }
1040
1041 Space* GenCollectedHeap::space_containing(const void* addr) const {
1042 Space* res = _young_gen->space_containing(addr);
1043 if (res != NULL) {
1044 return res;
1045 }
1046 res = _old_gen->space_containing(addr);
1047 assert(res != NULL, "Could not find containing space");
1048 return res;
1049 }
1050
1051 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1052 assert(is_in_reserved(addr), "block_start of address outside of heap");
1053 if (_young_gen->is_in_reserved(addr)) {
1054 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
1055 return _young_gen->block_start(addr);
1056 }
1057
1058 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1059 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
1060 return _old_gen->block_start(addr);
1061 }
1062
1063 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1064 assert(is_in_reserved(addr), "block_size of address outside of heap");
1065 if (_young_gen->is_in_reserved(addr)) {
1066 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation");
1067 return _young_gen->block_size(addr);
1068 }
1069
1070 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1071 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation");
1072 return _old_gen->block_size(addr);
1073 }
1074
1075 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1076 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1077 assert(block_start(addr) == addr, "addr must be a block start");
1078 if (_young_gen->is_in_reserved(addr)) {
1079 return _young_gen->block_is_obj(addr);
1080 }
1081
1082 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address");
1083 return _old_gen->block_is_obj(addr);
1084 }
1085
1086 bool GenCollectedHeap::supports_tlab_allocation() const {
1087 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1088 return _young_gen->supports_tlab_allocation();
1089 }
1090
1091 size_t GenCollectedHeap::tlab_capacity(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->tlab_capacity();
1095 }
1096 return 0;
1097 }
1098
1099 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1100 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1101 if (_young_gen->supports_tlab_allocation()) {
1102 return _young_gen->tlab_used();
1103 }
1104 return 0;
1105 }
1106
1107 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1108 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!");
1109 if (_young_gen->supports_tlab_allocation()) {
1110 return _young_gen->unsafe_max_tlab_alloc();
1111 }
1112 return 0;
1113 }
1114
1115 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1116 bool gc_overhead_limit_was_exceeded;
1117 return mem_allocate_work(size /* size */,
1118 true /* is_tlab */,
1119 &gc_overhead_limit_was_exceeded);
1120 }
1121
1122 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1123 // from the list headed by "*prev_ptr".
1124 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1125 bool first = true;
1126 size_t min_size = 0; // "first" makes this conceptually infinite.
1127 ScratchBlock **smallest_ptr, *smallest;
1128 ScratchBlock *cur = *prev_ptr;
1129 while (cur) {
1130 assert(*prev_ptr == cur, "just checking");
1131 if (first || cur->num_words < min_size) {
1132 smallest_ptr = prev_ptr;
1133 smallest = cur;
1134 min_size = smallest->num_words;
1135 first = false;
1136 }
1137 prev_ptr = &cur->next;
1138 cur = cur->next;
1139 }
1140 smallest = *smallest_ptr;
1141 *smallest_ptr = smallest->next;
1142 return smallest;
1143 }
1144
1145 // Sort the scratch block list headed by res into decreasing size order,
1146 // and set "res" to the result.
1147 static void sort_scratch_list(ScratchBlock*& list) {
1148 ScratchBlock* sorted = NULL;
1149 ScratchBlock* unsorted = list;
1150 while (unsorted) {
1151 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1152 smallest->next = sorted;
1153 sorted = smallest;
1154 }
1155 list = sorted;
1156 }
1157
1158 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1159 size_t max_alloc_words) {
1160 ScratchBlock* res = NULL;
1161 _young_gen->contribute_scratch(res, requestor, max_alloc_words);
1162 _old_gen->contribute_scratch(res, requestor, max_alloc_words);
1163 sort_scratch_list(res);
1164 return res;
1165 }
1166
1167 void GenCollectedHeap::release_scratch() {
1168 _young_gen->reset_scratch();
1169 _old_gen->reset_scratch();
1170 }
1171
1172 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1173 void do_generation(Generation* gen) {
1174 gen->prepare_for_verify();
1175 }
1176 };
1177
1178 void GenCollectedHeap::prepare_for_verify() {
1179 ensure_parsability(false); // no need to retire TLABs
1180 GenPrepareForVerifyClosure blk;
1181 generation_iterate(&blk, false);
1182 }
1183
1184 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1185 bool old_to_young) {
1186 if (old_to_young) {
1187 cl->do_generation(_old_gen);
1188 cl->do_generation(_young_gen);
1189 } else {
1190 cl->do_generation(_young_gen);
1191 cl->do_generation(_old_gen);
1192 }
1193 }
1194
1195 bool GenCollectedHeap::is_maximal_no_gc() const {
1196 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc();
1197 }
1198
1199 void GenCollectedHeap::save_marks() {
1200 _young_gen->save_marks();
1201 _old_gen->save_marks();
1202 }
1203
1204 GenCollectedHeap* GenCollectedHeap::heap() {
1205 CollectedHeap* heap = Universe::heap();
1206 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1207 assert(heap->kind() == CollectedHeap::SerialHeap ||
1208 heap->kind() == CollectedHeap::CMSHeap, "Not a GenCollectedHeap");
1209 return (GenCollectedHeap*) heap;
1210 }
1211
1212 void GenCollectedHeap::prepare_for_compaction() {
1213 // Start by compacting into same gen.
1214 CompactPoint cp(_old_gen);
1215 _old_gen->prepare_for_compaction(&cp);
1216 _young_gen->prepare_for_compaction(&cp);
1217 }
1218
1219 void GenCollectedHeap::verify(VerifyOption option /* ignored */) {
1220 log_debug(gc, verify)("%s", _old_gen->name());
1221 _old_gen->verify();
1222
1223 log_debug(gc, verify)("%s", _old_gen->name());
1224 _young_gen->verify();
1225
1226 log_debug(gc, verify)("RemSet");
1227 rem_set()->verify();
1228 }
1229
1230 void GenCollectedHeap::print_on(outputStream* st) const {
1231 _young_gen->print_on(st);
1232 _old_gen->print_on(st);
1233 MetaspaceAux::print_on(st);
1234 }
1235
1236 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1237 }
1238
1239 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1240 }
1241
1242 void GenCollectedHeap::print_tracing_info() const {
1243 if (log_is_enabled(Debug, gc, heap, exit)) {
1244 LogStreamHandle(Debug, gc, heap, exit) lsh;
1245 _young_gen->print_summary_info_on(&lsh);
1246 _old_gen->print_summary_info_on(&lsh);
1247 }
1248 }
1249
1250 void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const {
1251 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1252 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K);
1253 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
1254 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K);
1255 }
1256
1257 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1258 private:
1259 bool _full;
1260 public:
1261 void do_generation(Generation* gen) {
1262 gen->gc_prologue(_full);
1263 }
1264 GenGCPrologueClosure(bool full) : _full(full) {};
1265 };
1266
1267 void GenCollectedHeap::gc_prologue(bool full) {
1268 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1269
1270 // Fill TLAB's and such
1271 CollectedHeap::accumulate_statistics_all_tlabs();
1272 ensure_parsability(true); // retire TLABs
1273
1274 // Walk generations
1275 GenGCPrologueClosure blk(full);
1276 generation_iterate(&blk, false); // not old-to-young.
1277 };
1278
1279 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1280 private:
1281 bool _full;
1282 public:
1283 void do_generation(Generation* gen) {
1284 gen->gc_epilogue(_full);
1285 }
1286 GenGCEpilogueClosure(bool full) : _full(full) {};
1287 };
1288
1289 void GenCollectedHeap::gc_epilogue(bool full) {
1290 #if COMPILER2_OR_JVMCI
1291 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1292 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1293 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1294 #endif // COMPILER2_OR_JVMCI
1295
1296 resize_all_tlabs();
1297
1298 GenGCEpilogueClosure blk(full);
1299 generation_iterate(&blk, false); // not old-to-young.
1300
1301 if (!CleanChunkPoolAsync) {
1302 Chunk::clean_chunk_pool();
1303 }
1304
1305 MetaspaceCounters::update_performance_counters();
1306 CompressedClassSpaceCounters::update_performance_counters();
1307 };
1308
1309 #ifndef PRODUCT
1310 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1311 private:
1312 public:
1313 void do_generation(Generation* gen) {
1314 gen->record_spaces_top();
1315 }
1316 };
1317
1318 void GenCollectedHeap::record_gen_tops_before_GC() {
1319 if (ZapUnusedHeapArea) {
1320 GenGCSaveTopsBeforeGCClosure blk;
1321 generation_iterate(&blk, false); // not old-to-young.
1322 }
1323 }
1324 #endif // not PRODUCT
1325
1326 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1327 public:
1328 void do_generation(Generation* gen) {
1329 gen->ensure_parsability();
1330 }
1331 };
1332
1333 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1334 CollectedHeap::ensure_parsability(retire_tlabs);
1335 GenEnsureParsabilityClosure ep_cl;
1336 generation_iterate(&ep_cl, false);
1337 }
1338
1339 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1340 oop obj,
1341 size_t obj_size) {
1342 guarantee(old_gen == _old_gen, "We only get here with an old generation");
1343 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1344 HeapWord* result = NULL;
1345
1346 result = old_gen->expand_and_allocate(obj_size, false);
1347
1348 if (result != NULL) {
1349 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1350 }
1351 return oop(result);
1352 }
1353
1354 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1355 jlong _time; // in ms
1356 jlong _now; // in ms
1357
1358 public:
1359 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1360
1361 jlong time() { return _time; }
1362
1363 void do_generation(Generation* gen) {
1364 _time = MIN2(_time, gen->time_of_last_gc(_now));
1365 }
1366 };
1367
1368 jlong GenCollectedHeap::millis_since_last_gc() {
1369 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1370 // provided the underlying platform provides such a time source
1371 // (and it is bug free). So we still have to guard against getting
1372 // back a time later than 'now'.
1373 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1374 GenTimeOfLastGCClosure tolgc_cl(now);
1375 // iterate over generations getting the oldest
1376 // time that a generation was collected
1377 generation_iterate(&tolgc_cl, false);
1378
1379 jlong retVal = now - tolgc_cl.time();
1380 if (retVal < 0) {
1381 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT
1382 ". returning zero instead.", retVal);
1383 return 0;
1384 }
1385 return retVal;
1386 }