1 /*
2 * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/codeCache.hpp"
30 #include "code/icBuffer.hpp"
31 #include "gc_implementation/shared/collectorCounters.hpp"
32 #include "gc_implementation/shared/gcTrace.hpp"
33 #include "gc_implementation/shared/gcTraceTime.hpp"
34 #include "gc_implementation/shared/vmGCOperations.hpp"
35 #include "gc_interface/collectedHeap.inline.hpp"
36 #include "memory/filemap.hpp"
37 #include "memory/gcLocker.inline.hpp"
38 #include "memory/genCollectedHeap.hpp"
39 #include "memory/genOopClosures.inline.hpp"
40 #include "memory/generation.inline.hpp"
41 #include "memory/generationSpec.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/sharedHeap.hpp"
44 #include "memory/space.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/oop.inline2.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/fprofiler.hpp"
49 #include "runtime/handles.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/java.hpp"
52 #include "runtime/vmThread.hpp"
53 #include "services/management.hpp"
54 #include "services/memoryService.hpp"
55 #include "utilities/vmError.hpp"
56 #include "utilities/workgroup.hpp"
57 #include "utilities/macros.hpp"
58 #if INCLUDE_ALL_GCS
59 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
60 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp"
61 #endif // INCLUDE_ALL_GCS
62 #if INCLUDE_JFR
63 #include "jfr/jfr.hpp"
64 #endif // INCLUDE_JFR
65
66 GenCollectedHeap* GenCollectedHeap::_gch;
67 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
68
69 // The set of potentially parallel tasks in root scanning.
70 enum GCH_strong_roots_tasks {
71 GCH_PS_Universe_oops_do,
72 GCH_PS_JNIHandles_oops_do,
73 GCH_PS_ObjectSynchronizer_oops_do,
74 GCH_PS_FlatProfiler_oops_do,
75 GCH_PS_Management_oops_do,
76 GCH_PS_SystemDictionary_oops_do,
77 GCH_PS_ClassLoaderDataGraph_oops_do,
78 GCH_PS_jvmti_oops_do,
79 GCH_PS_CodeCache_oops_do,
80 GCH_PS_younger_gens,
81 // Leave this one last.
82 GCH_PS_NumElements
83 };
84
85 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
86 SharedHeap(policy),
87 _gen_policy(policy),
88 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
89 _full_collections_completed(0)
90 {
91 assert(policy != NULL, "Sanity check");
92 }
93
94 jint GenCollectedHeap::initialize() {
95 CollectedHeap::pre_initialize();
96
97 int i;
98 _n_gens = gen_policy()->number_of_generations();
99
100 // While there are no constraints in the GC code that HeapWordSize
101 // be any particular value, there are multiple other areas in the
102 // system which believe this to be true (e.g. oop->object_size in some
103 // cases incorrectly returns the size in wordSize units rather than
104 // HeapWordSize).
105 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
106
107 // The heap must be at least as aligned as generations.
108 size_t gen_alignment = Generation::GenGrain;
109
110 _gen_specs = gen_policy()->generations();
111
112 // Make sure the sizes are all aligned.
113 for (i = 0; i < _n_gens; i++) {
114 _gen_specs[i]->align(gen_alignment);
115 }
116
117 // Allocate space for the heap.
118
119 char* heap_address;
120 size_t total_reserved = 0;
121 int n_covered_regions = 0;
122 ReservedSpace heap_rs;
123
124 size_t heap_alignment = collector_policy()->heap_alignment();
125
126 heap_address = allocate(heap_alignment, &total_reserved,
127 &n_covered_regions, &heap_rs);
128
129 if (!heap_rs.is_reserved()) {
130 vm_shutdown_during_initialization(
131 "Could not reserve enough space for object heap");
132 return JNI_ENOMEM;
133 }
134
135 _reserved = MemRegion((HeapWord*)heap_rs.base(),
136 (HeapWord*)(heap_rs.base() + heap_rs.size()));
137
138 // It is important to do this in a way such that concurrent readers can't
139 // temporarily think somethings in the heap. (Seen this happen in asserts.)
140 _reserved.set_word_size(0);
141 _reserved.set_start((HeapWord*)heap_rs.base());
142 size_t actual_heap_size = heap_rs.size();
143 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
144
145 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
146 set_barrier_set(rem_set()->bs());
147
148 _gch = this;
149
150 for (i = 0; i < _n_gens; i++) {
151 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(), false, false);
152 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
153 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
154 }
155 clear_incremental_collection_failed();
156
157 #if INCLUDE_ALL_GCS
158 // If we are running CMS, create the collector responsible
159 // for collecting the CMS generations.
160 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
161 bool success = create_cms_collector();
162 if (!success) return JNI_ENOMEM;
163 }
164 #endif // INCLUDE_ALL_GCS
165
166 return JNI_OK;
167 }
168
169
170 char* GenCollectedHeap::allocate(size_t alignment,
171 size_t* _total_reserved,
172 int* _n_covered_regions,
173 ReservedSpace* heap_rs){
174 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
175 "the maximum representable size";
176
177 // Now figure out the total size.
178 size_t total_reserved = 0;
179 int n_covered_regions = 0;
180 const size_t pageSize = UseLargePages ?
181 os::large_page_size() : os::vm_page_size();
182
183 assert(alignment % pageSize == 0, "Must be");
184
185 for (int i = 0; i < _n_gens; i++) {
186 total_reserved += _gen_specs[i]->max_size();
187 if (total_reserved < _gen_specs[i]->max_size()) {
188 vm_exit_during_initialization(overflow_msg);
189 }
190 n_covered_regions += _gen_specs[i]->n_covered_regions();
191 }
192 assert(total_reserved % alignment == 0,
193 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
194 SIZE_FORMAT, total_reserved, alignment));
195
196 // Needed until the cardtable is fixed to have the right number
197 // of covered regions.
198 n_covered_regions += 2;
199
200 *_total_reserved = total_reserved;
201 *_n_covered_regions = n_covered_regions;
202
203 *heap_rs = Universe::reserve_heap(total_reserved, alignment);
204 return heap_rs->base();
205 }
206
207
208 void GenCollectedHeap::post_initialize() {
209 SharedHeap::post_initialize();
210 TwoGenerationCollectorPolicy *policy =
211 (TwoGenerationCollectorPolicy *)collector_policy();
212 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
213 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
214 assert(def_new_gen->kind() == Generation::DefNew ||
215 def_new_gen->kind() == Generation::ParNew ||
216 def_new_gen->kind() == Generation::ASParNew,
217 "Wrong generation kind");
218
219 Generation* old_gen = get_gen(1);
220 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
221 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
222 old_gen->kind() == Generation::MarkSweepCompact,
223 "Wrong generation kind");
224
225 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
226 old_gen->capacity(),
227 def_new_gen->from()->capacity());
228 policy->initialize_gc_policy_counters();
229 }
230
231 void GenCollectedHeap::ref_processing_init() {
232 SharedHeap::ref_processing_init();
233 for (int i = 0; i < _n_gens; i++) {
234 _gens[i]->ref_processor_init();
235 }
236 }
237
238 size_t GenCollectedHeap::capacity() const {
239 size_t res = 0;
240 for (int i = 0; i < _n_gens; i++) {
241 res += _gens[i]->capacity();
242 }
243 return res;
244 }
245
246 size_t GenCollectedHeap::used() const {
247 size_t res = 0;
248 for (int i = 0; i < _n_gens; i++) {
249 res += _gens[i]->used();
250 }
251 return res;
252 }
253
254 // Save the "used_region" for generations level and lower.
255 void GenCollectedHeap::save_used_regions(int level) {
256 assert(level < _n_gens, "Illegal level parameter");
257 for (int i = level; i >= 0; i--) {
258 _gens[i]->save_used_region();
259 }
260 }
261
262 size_t GenCollectedHeap::max_capacity() const {
263 size_t res = 0;
264 for (int i = 0; i < _n_gens; i++) {
265 res += _gens[i]->max_capacity();
266 }
267 return res;
268 }
269
270 // Update the _full_collections_completed counter
271 // at the end of a stop-world full GC.
272 unsigned int GenCollectedHeap::update_full_collections_completed() {
273 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
274 assert(_full_collections_completed <= _total_full_collections,
275 "Can't complete more collections than were started");
276 _full_collections_completed = _total_full_collections;
277 ml.notify_all();
278 return _full_collections_completed;
279 }
280
281 // Update the _full_collections_completed counter, as appropriate,
282 // at the end of a concurrent GC cycle. Note the conditional update
283 // below to allow this method to be called by a concurrent collector
284 // without synchronizing in any manner with the VM thread (which
285 // may already have initiated a STW full collection "concurrently").
286 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
287 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
288 assert((_full_collections_completed <= _total_full_collections) &&
289 (count <= _total_full_collections),
290 "Can't complete more collections than were started");
291 if (count > _full_collections_completed) {
292 _full_collections_completed = count;
293 ml.notify_all();
294 }
295 return _full_collections_completed;
296 }
297
298
299 #ifndef PRODUCT
300 // Override of memory state checking method in CollectedHeap:
301 // Some collectors (CMS for example) can't have badHeapWordVal written
302 // in the first two words of an object. (For instance , in the case of
303 // CMS these words hold state used to synchronize between certain
304 // (concurrent) GC steps and direct allocating mutators.)
305 // The skip_header_HeapWords() method below, allows us to skip
306 // over the requisite number of HeapWord's. Note that (for
307 // generational collectors) this means that those many words are
308 // skipped in each object, irrespective of the generation in which
309 // that object lives. The resultant loss of precision seems to be
310 // harmless and the pain of avoiding that imprecision appears somewhat
311 // higher than we are prepared to pay for such rudimentary debugging
312 // support.
313 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
314 size_t size) {
315 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
316 // We are asked to check a size in HeapWords,
317 // but the memory is mangled in juint words.
318 juint* start = (juint*) (addr + skip_header_HeapWords());
319 juint* end = (juint*) (addr + size);
320 for (juint* slot = start; slot < end; slot += 1) {
321 assert(*slot == badHeapWordVal,
322 "Found non badHeapWordValue in pre-allocation check");
323 }
324 }
325 }
326 #endif
327
328 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
329 bool is_tlab,
330 bool first_only) {
331 HeapWord* res;
332 for (int i = 0; i < _n_gens; i++) {
333 if (_gens[i]->should_allocate(size, is_tlab)) {
334 res = _gens[i]->allocate(size, is_tlab);
335 if (res != NULL) return res;
336 else if (first_only) break;
337 }
338 }
339 // Otherwise...
340 return NULL;
341 }
342
343 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
344 bool* gc_overhead_limit_was_exceeded) {
345 return collector_policy()->mem_allocate_work(size,
346 false /* is_tlab */,
347 gc_overhead_limit_was_exceeded);
348 }
349
350 bool GenCollectedHeap::must_clear_all_soft_refs() {
351 return _gc_cause == GCCause::_last_ditch_collection;
352 }
353
354 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
355 return UseConcMarkSweepGC &&
356 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
357 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
358 }
359
360 void GenCollectedHeap::do_collection(bool full,
361 bool clear_all_soft_refs,
362 size_t size,
363 bool is_tlab,
364 int max_level) {
365 bool prepared_for_verification = false;
366 ResourceMark rm;
367 DEBUG_ONLY(Thread* my_thread = Thread::current();)
368
369 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
370 assert(my_thread->is_VM_thread() ||
371 my_thread->is_ConcurrentGC_thread(),
372 "incorrect thread type capability");
373 assert(Heap_lock->is_locked(),
374 "the requesting thread should have the Heap_lock");
375 guarantee(!is_gc_active(), "collection is not reentrant");
376 assert(max_level < n_gens(), "sanity check");
377
378 if (GC_locker::check_active_before_gc()) {
379 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
380 }
381
382 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
383 collector_policy()->should_clear_all_soft_refs();
384
385 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
386
387 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
388
389 print_heap_before_gc();
390
391 {
392 FlagSetting fl(_is_gc_active, true);
393
394 bool complete = full && (max_level == (n_gens()-1));
395 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
396 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
397 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
398 // so we can assume here that the next GC id is what we want.
399 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL, GCId::peek());
400
401 gc_prologue(complete);
402 increment_total_collections(complete);
403
404 size_t gch_prev_used = used();
405
406 int starting_level = 0;
407 if (full) {
408 // Search for the oldest generation which will collect all younger
409 // generations, and start collection loop there.
410 for (int i = max_level; i >= 0; i--) {
411 if (_gens[i]->full_collects_younger_generations()) {
412 starting_level = i;
413 break;
414 }
415 }
416 }
417
418 bool must_restore_marks_for_biased_locking = false;
419
420 int max_level_collected = starting_level;
421 for (int i = starting_level; i <= max_level; i++) {
422 if (_gens[i]->should_collect(full, size, is_tlab)) {
423 if (i == n_gens() - 1) { // a major collection is to happen
424 if (!complete) {
425 // The full_collections increment was missed above.
426 increment_total_full_collections();
427 }
428 pre_full_gc_dump(NULL); // do any pre full gc dumps
429 }
430 // Timer for individual generations. Last argument is false: no CR
431 // FIXME: We should try to start the timing earlier to cover more of the GC pause
432 // The PrintGCDetails logging starts before we have incremented the GC id. We will do that later
433 // so we can assume here that the next GC id is what we want.
434 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL, GCId::peek());
435 TraceCollectorStats tcs(_gens[i]->counters());
436 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
437
438 size_t prev_used = _gens[i]->used();
439 _gens[i]->stat_record()->invocations++;
440 _gens[i]->stat_record()->accumulated_time.start();
441
442 // Must be done anew before each collection because
443 // a previous collection will do mangling and will
444 // change top of some spaces.
445 record_gen_tops_before_GC();
446
447 if (PrintGC && Verbose) {
448 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
449 i,
450 _gens[i]->stat_record()->invocations,
451 size*HeapWordSize);
452 }
453
454 if (VerifyBeforeGC && i >= VerifyGCLevel &&
455 total_collections() >= VerifyGCStartAt) {
456 HandleMark hm; // Discard invalid handles created during verification
457 if (!prepared_for_verification) {
458 prepare_for_verify();
459 prepared_for_verification = true;
460 }
461 Universe::verify(" VerifyBeforeGC:");
462 }
463 COMPILER2_PRESENT(DerivedPointerTable::clear());
464
465 if (!must_restore_marks_for_biased_locking &&
466 _gens[i]->performs_in_place_marking()) {
467 // We perform this mark word preservation work lazily
468 // because it's only at this point that we know whether we
469 // absolutely have to do it; we want to avoid doing it for
470 // scavenge-only collections where it's unnecessary
471 must_restore_marks_for_biased_locking = true;
472 BiasedLocking::preserve_marks();
473 }
474
475 // Do collection work
476 {
477 // Note on ref discovery: For what appear to be historical reasons,
478 // GCH enables and disabled (by enqueing) refs discovery.
479 // In the future this should be moved into the generation's
480 // collect method so that ref discovery and enqueueing concerns
481 // are local to a generation. The collect method could return
482 // an appropriate indication in the case that notification on
483 // the ref lock was needed. This will make the treatment of
484 // weak refs more uniform (and indeed remove such concerns
485 // from GCH). XXX
486
487 HandleMark hm; // Discard invalid handles created during gc
488 save_marks(); // save marks for all gens
489 // We want to discover references, but not process them yet.
490 // This mode is disabled in process_discovered_references if the
491 // generation does some collection work, or in
492 // enqueue_discovered_references if the generation returns
493 // without doing any work.
494 ReferenceProcessor* rp = _gens[i]->ref_processor();
495 // If the discovery of ("weak") refs in this generation is
496 // atomic wrt other collectors in this configuration, we
497 // are guaranteed to have empty discovered ref lists.
498 if (rp->discovery_is_atomic()) {
499 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
500 rp->setup_policy(do_clear_all_soft_refs);
501 } else {
502 // collect() below will enable discovery as appropriate
503 }
504 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
505 if (!rp->enqueuing_is_done()) {
506 rp->enqueue_discovered_references();
507 } else {
508 rp->set_enqueuing_is_done(false);
509 }
510 rp->verify_no_references_recorded();
511 }
512 max_level_collected = i;
513
514 // Determine if allocation request was met.
515 if (size > 0) {
516 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
517 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
518 size = 0;
519 }
520 }
521 }
522
523 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
524
525 _gens[i]->stat_record()->accumulated_time.stop();
526
527 update_gc_stats(i, full);
528
529 if (VerifyAfterGC && i >= VerifyGCLevel &&
530 total_collections() >= VerifyGCStartAt) {
531 HandleMark hm; // Discard invalid handles created during verification
532 Universe::verify(" VerifyAfterGC:");
533 }
534
535 if (PrintGCDetails) {
536 gclog_or_tty->print(":");
537 _gens[i]->print_heap_change(prev_used);
538 }
539 }
540 }
541
542 // Update "complete" boolean wrt what actually transpired --
543 // for instance, a promotion failure could have led to
544 // a whole heap collection.
545 complete = complete || (max_level_collected == n_gens() - 1);
546
547 if (complete) { // We did a "major" collection
548 // FIXME: See comment at pre_full_gc_dump call
549 post_full_gc_dump(NULL); // do any post full gc dumps
550 }
551
552 if (PrintGCDetails) {
553 print_heap_change(gch_prev_used);
554
555 // Print metaspace info for full GC with PrintGCDetails flag.
556 if (complete) {
557 MetaspaceAux::print_metaspace_change(metadata_prev_used);
558 }
559 }
560
561 for (int j = max_level_collected; j >= 0; j -= 1) {
562 // Adjust generation sizes.
563 _gens[j]->compute_new_size();
564 }
565
566 if (complete) {
567 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
568 ClassLoaderDataGraph::purge();
569 MetaspaceAux::verify_metrics();
570 // Resize the metaspace capacity after full collections
571 MetaspaceGC::compute_new_size();
572 update_full_collections_completed();
573 }
574
575 // Track memory usage and detect low memory after GC finishes
576 MemoryService::track_memory_usage();
577
578 gc_epilogue(complete);
579
580 if (must_restore_marks_for_biased_locking) {
581 BiasedLocking::restore_marks();
582 }
583 }
584
585 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
586 AdaptiveSizePolicyOutput(sp, total_collections());
587
588 print_heap_after_gc();
589
590 #ifdef TRACESPINNING
591 ParallelTaskTerminator::print_termination_counts();
592 #endif
593 }
594
595 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
596 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
597 }
598
599 void GenCollectedHeap::set_par_threads(uint t) {
600 SharedHeap::set_par_threads(t);
601 set_n_termination(t);
602 }
603
604 void GenCollectedHeap::set_n_termination(uint t) {
605 _process_strong_tasks->set_n_threads(t);
606 }
607
608 #ifdef ASSERT
609 class AssertNonScavengableClosure: public OopClosure {
610 public:
611 virtual void do_oop(oop* p) {
612 assert(!Universe::heap()->is_in_partial_collection(*p),
613 "Referent should not be scavengable."); }
614 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
615 };
616 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
617 #endif
618
619 void GenCollectedHeap::process_roots(bool activate_scope,
620 ScanningOption so,
621 OopClosure* strong_roots,
622 OopClosure* weak_roots,
623 CLDClosure* strong_cld_closure,
624 CLDClosure* weak_cld_closure,
625 CodeBlobClosure* code_roots) {
626 StrongRootsScope srs(this, activate_scope);
627
628 // General roots.
629 assert(_strong_roots_parity != 0, "must have called prologue code");
630 assert(code_roots != NULL, "code root closure should always be set");
631 // _n_termination for _process_strong_tasks should be set up stream
632 // in a method not running in a GC worker. Otherwise the GC worker
633 // could be trying to change the termination condition while the task
634 // is executing in another GC worker.
635
636 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) {
637 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
638 }
639
640 // Some CLDs contained in the thread frames should be considered strong.
641 // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
642 CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
643 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
644 CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
645
646 Threads::possibly_parallel_oops_do(strong_roots, roots_from_clds_p, roots_from_code_p);
647
648 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) {
649 Universe::oops_do(strong_roots);
650 }
651 // Global (strong) JNI handles
652 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) {
653 JNIHandles::oops_do(strong_roots);
654 }
655
656 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) {
657 ObjectSynchronizer::oops_do(strong_roots);
658 }
659 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) {
660 FlatProfiler::oops_do(strong_roots);
661 }
662 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) {
663 Management::oops_do(strong_roots);
664 }
665 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) {
666 JvmtiExport::oops_do(strong_roots);
667 }
668
669 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) {
670 SystemDictionary::roots_oops_do(strong_roots, weak_roots);
671 }
672
673 // All threads execute the following. A specific chunk of buckets
674 // from the StringTable are the individual tasks.
675 if (weak_roots != NULL) {
676 if (CollectedHeap::use_parallel_gc_threads()) {
677 StringTable::possibly_parallel_oops_do(weak_roots);
678 } else {
679 StringTable::oops_do(weak_roots);
680 }
681 }
682
683 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) {
684 if (so & SO_ScavengeCodeCache) {
685 assert(code_roots != NULL, "must supply closure for code cache");
686
687 // We only visit parts of the CodeCache when scavenging.
688 CodeCache::scavenge_root_nmethods_do(code_roots);
689 }
690 if (so & SO_AllCodeCache) {
691 assert(code_roots != NULL, "must supply closure for code cache");
692
693 // CMSCollector uses this to do intermediate-strength collections.
694 // We scan the entire code cache, since CodeCache::do_unloading is not called.
695 CodeCache::blobs_do(code_roots);
696 }
697 // Verify that the code cache contents are not subject to
698 // movement by a scavenging collection.
699 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
700 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
701 }
702
703 }
704
705 void GenCollectedHeap::gen_process_roots(int level,
706 bool younger_gens_as_roots,
707 bool activate_scope,
708 ScanningOption so,
709 bool only_strong_roots,
710 OopsInGenClosure* not_older_gens,
711 OopsInGenClosure* older_gens,
712 CLDClosure* cld_closure) {
713 const bool is_adjust_phase = !only_strong_roots && !younger_gens_as_roots;
714
715 bool is_moving_collection = false;
716 if (level == 0 || is_adjust_phase) {
717 // young collections are always moving
718 is_moving_collection = true;
719 }
720
721 MarkingCodeBlobClosure mark_code_closure(not_older_gens, is_moving_collection);
722 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : not_older_gens;
723 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure;
724
725 process_roots(activate_scope, so,
726 not_older_gens, weak_roots,
727 cld_closure, weak_cld_closure,
728 &mark_code_closure);
729
730 if (younger_gens_as_roots) {
731 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
732 for (int i = 0; i < level; i++) {
733 not_older_gens->set_generation(_gens[i]);
734 _gens[i]->oop_iterate(not_older_gens);
735 }
736 not_older_gens->reset_generation();
737 }
738 }
739 // When collection is parallel, all threads get to cooperate to do
740 // older-gen scanning.
741 for (int i = level+1; i < _n_gens; i++) {
742 older_gens->set_generation(_gens[i]);
743 rem_set()->younger_refs_iterate(_gens[i], older_gens);
744 older_gens->reset_generation();
745 }
746
747 _process_strong_tasks->all_tasks_completed();
748 }
749
750
751 class AlwaysTrueClosure: public BoolObjectClosure {
752 public:
753 bool do_object_b(oop p) { return true; }
754 };
755 static AlwaysTrueClosure always_true;
756
757 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) {
758 JNIHandles::weak_oops_do(&always_true, root_closure);
759 JFR_ONLY(Jfr::weak_oops_do(&always_true, root_closure));
760 for (int i = 0; i < _n_gens; i++) {
761 _gens[i]->ref_processor()->weak_oops_do(root_closure);
762 }
763 }
764
765 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
766 void GenCollectedHeap:: \
767 oop_since_save_marks_iterate(int level, \
768 OopClosureType* cur, \
769 OopClosureType* older) { \
770 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
771 for (int i = level+1; i < n_gens(); i++) { \
772 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
773 } \
774 }
775
776 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
777
778 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
779
780 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
781 for (int i = level; i < _n_gens; i++) {
782 if (!_gens[i]->no_allocs_since_save_marks()) return false;
783 }
784 return true;
785 }
786
787 bool GenCollectedHeap::supports_inline_contig_alloc() const {
788 return _gens[0]->supports_inline_contig_alloc();
789 }
790
791 HeapWord** GenCollectedHeap::top_addr() const {
792 return _gens[0]->top_addr();
793 }
794
795 HeapWord** GenCollectedHeap::end_addr() const {
796 return _gens[0]->end_addr();
797 }
798
799 // public collection interfaces
800
801 void GenCollectedHeap::collect(GCCause::Cause cause) {
802 if (should_do_concurrent_full_gc(cause)) {
803 #if INCLUDE_ALL_GCS
804 // mostly concurrent full collection
805 collect_mostly_concurrent(cause);
806 #else // INCLUDE_ALL_GCS
807 ShouldNotReachHere();
808 #endif // INCLUDE_ALL_GCS
809 } else if (cause == GCCause::_wb_young_gc) {
810 // minor collection for WhiteBox API
811 collect(cause, 0);
812 } else {
813 #ifdef ASSERT
814 if (cause == GCCause::_scavenge_alot) {
815 // minor collection only
816 collect(cause, 0);
817 } else {
818 // Stop-the-world full collection
819 collect(cause, n_gens() - 1);
820 }
821 #else
822 // Stop-the-world full collection
823 collect(cause, n_gens() - 1);
824 #endif
825 }
826 }
827
828 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
829 // The caller doesn't have the Heap_lock
830 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
831 MutexLocker ml(Heap_lock);
832 collect_locked(cause, max_level);
833 }
834
835 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
836 // The caller has the Heap_lock
837 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
838 collect_locked(cause, n_gens() - 1);
839 }
840
841 // this is the private collection interface
842 // The Heap_lock is expected to be held on entry.
843
844 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
845 // Read the GC count while holding the Heap_lock
846 unsigned int gc_count_before = total_collections();
847 unsigned int full_gc_count_before = total_full_collections();
848 {
849 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
850 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
851 cause, max_level);
852 VMThread::execute(&op);
853 }
854 }
855
856 #if INCLUDE_ALL_GCS
857 bool GenCollectedHeap::create_cms_collector() {
858
859 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
860 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)),
861 "Unexpected generation kinds");
862 // Skip two header words in the block content verification
863 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
864 CMSCollector* collector = new CMSCollector(
865 (ConcurrentMarkSweepGeneration*)_gens[1],
866 _rem_set->as_CardTableRS(),
867 (ConcurrentMarkSweepPolicy*) collector_policy());
868
869 if (collector == NULL || !collector->completed_initialization()) {
870 if (collector) {
871 delete collector; // Be nice in embedded situation
872 }
873 vm_shutdown_during_initialization("Could not create CMS collector");
874 return false;
875 }
876 return true; // success
877 }
878
879 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
880 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
881
882 MutexLocker ml(Heap_lock);
883 // Read the GC counts while holding the Heap_lock
884 unsigned int full_gc_count_before = total_full_collections();
885 unsigned int gc_count_before = total_collections();
886 {
887 MutexUnlocker mu(Heap_lock);
888 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
889 VMThread::execute(&op);
890 }
891 }
892 #endif // INCLUDE_ALL_GCS
893
894 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
895 do_full_collection(clear_all_soft_refs, _n_gens - 1);
896 }
897
898 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
899 int max_level) {
900 int local_max_level;
901 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
902 gc_cause() == GCCause::_gc_locker) {
903 local_max_level = 0;
904 } else {
905 local_max_level = max_level;
906 }
907
908 do_collection(true /* full */,
909 clear_all_soft_refs /* clear_all_soft_refs */,
910 0 /* size */,
911 false /* is_tlab */,
912 local_max_level /* max_level */);
913 // Hack XXX FIX ME !!!
914 // A scavenge may not have been attempted, or may have
915 // been attempted and failed, because the old gen was too full
916 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
917 incremental_collection_will_fail(false /* don't consult_young */)) {
918 if (PrintGCDetails) {
919 gclog_or_tty->print_cr("GC locker: Trying a full collection "
920 "because scavenge failed");
921 }
922 // This time allow the old gen to be collected as well
923 do_collection(true /* full */,
924 clear_all_soft_refs /* clear_all_soft_refs */,
925 0 /* size */,
926 false /* is_tlab */,
927 n_gens() - 1 /* max_level */);
928 }
929 }
930
931 bool GenCollectedHeap::is_in_young(oop p) {
932 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
933 assert(result == _gens[0]->is_in_reserved(p),
934 err_msg("incorrect test - result=%d, p=" PTR_FORMAT, result, p2i((void*)p)));
935 return result;
936 }
937
938 // Returns "TRUE" iff "p" points into the committed areas of the heap.
939 bool GenCollectedHeap::is_in(const void* p) const {
940 #ifndef ASSERT
941 guarantee(VerifyBeforeGC ||
942 VerifyDuringGC ||
943 VerifyBeforeExit ||
944 VerifyDuringStartup ||
945 PrintAssembly ||
946 tty->count() != 0 || // already printing
947 VerifyAfterGC ||
948 VMError::fatal_error_in_progress(), "too expensive");
949
950 #endif
951 // This might be sped up with a cache of the last generation that
952 // answered yes.
953 for (int i = 0; i < _n_gens; i++) {
954 if (_gens[i]->is_in(p)) return true;
955 }
956 // Otherwise...
957 return false;
958 }
959
960 #ifdef ASSERT
961 // Don't implement this by using is_in_young(). This method is used
962 // in some cases to check that is_in_young() is correct.
963 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
964 assert(is_in_reserved(p) || p == NULL,
965 "Does not work if address is non-null and outside of the heap");
966 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
967 }
968 #endif
969
970 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) {
971 for (int i = 0; i < _n_gens; i++) {
972 _gens[i]->oop_iterate(cl);
973 }
974 }
975
976 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
977 for (int i = 0; i < _n_gens; i++) {
978 _gens[i]->object_iterate(cl);
979 }
980 }
981
982 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
983 for (int i = 0; i < _n_gens; i++) {
984 _gens[i]->safe_object_iterate(cl);
985 }
986 }
987
988 Space* GenCollectedHeap::space_containing(const void* addr) const {
989 for (int i = 0; i < _n_gens; i++) {
990 Space* res = _gens[i]->space_containing(addr);
991 if (res != NULL) return res;
992 }
993 // Otherwise...
994 assert(false, "Could not find containing space");
995 return NULL;
996 }
997
998
999 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1000 assert(is_in_reserved(addr), "block_start of address outside of heap");
1001 for (int i = 0; i < _n_gens; i++) {
1002 if (_gens[i]->is_in_reserved(addr)) {
1003 assert(_gens[i]->is_in(addr),
1004 "addr should be in allocated part of generation");
1005 return _gens[i]->block_start(addr);
1006 }
1007 }
1008 assert(false, "Some generation should contain the address");
1009 return NULL;
1010 }
1011
1012 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1013 assert(is_in_reserved(addr), "block_size of address outside of heap");
1014 for (int i = 0; i < _n_gens; i++) {
1015 if (_gens[i]->is_in_reserved(addr)) {
1016 assert(_gens[i]->is_in(addr),
1017 "addr should be in allocated part of generation");
1018 return _gens[i]->block_size(addr);
1019 }
1020 }
1021 assert(false, "Some generation should contain the address");
1022 return 0;
1023 }
1024
1025 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1026 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1027 assert(block_start(addr) == addr, "addr must be a block start");
1028 for (int i = 0; i < _n_gens; i++) {
1029 if (_gens[i]->is_in_reserved(addr)) {
1030 return _gens[i]->block_is_obj(addr);
1031 }
1032 }
1033 assert(false, "Some generation should contain the address");
1034 return false;
1035 }
1036
1037 bool GenCollectedHeap::supports_tlab_allocation() const {
1038 for (int i = 0; i < _n_gens; i += 1) {
1039 if (_gens[i]->supports_tlab_allocation()) {
1040 return true;
1041 }
1042 }
1043 return false;
1044 }
1045
1046 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1047 size_t result = 0;
1048 for (int i = 0; i < _n_gens; i += 1) {
1049 if (_gens[i]->supports_tlab_allocation()) {
1050 result += _gens[i]->tlab_capacity();
1051 }
1052 }
1053 return result;
1054 }
1055
1056 size_t GenCollectedHeap::tlab_used(Thread* thr) const {
1057 size_t result = 0;
1058 for (int i = 0; i < _n_gens; i += 1) {
1059 if (_gens[i]->supports_tlab_allocation()) {
1060 result += _gens[i]->tlab_used();
1061 }
1062 }
1063 return result;
1064 }
1065
1066 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1067 size_t result = 0;
1068 for (int i = 0; i < _n_gens; i += 1) {
1069 if (_gens[i]->supports_tlab_allocation()) {
1070 result += _gens[i]->unsafe_max_tlab_alloc();
1071 }
1072 }
1073 return result;
1074 }
1075
1076 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1077 bool gc_overhead_limit_was_exceeded;
1078 return collector_policy()->mem_allocate_work(size /* size */,
1079 true /* is_tlab */,
1080 &gc_overhead_limit_was_exceeded);
1081 }
1082
1083 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1084 // from the list headed by "*prev_ptr".
1085 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1086 bool first = true;
1087 size_t min_size = 0; // "first" makes this conceptually infinite.
1088 ScratchBlock **smallest_ptr, *smallest;
1089 ScratchBlock *cur = *prev_ptr;
1090 while (cur) {
1091 assert(*prev_ptr == cur, "just checking");
1092 if (first || cur->num_words < min_size) {
1093 smallest_ptr = prev_ptr;
1094 smallest = cur;
1095 min_size = smallest->num_words;
1096 first = false;
1097 }
1098 prev_ptr = &cur->next;
1099 cur = cur->next;
1100 }
1101 smallest = *smallest_ptr;
1102 *smallest_ptr = smallest->next;
1103 return smallest;
1104 }
1105
1106 // Sort the scratch block list headed by res into decreasing size order,
1107 // and set "res" to the result.
1108 static void sort_scratch_list(ScratchBlock*& list) {
1109 ScratchBlock* sorted = NULL;
1110 ScratchBlock* unsorted = list;
1111 while (unsorted) {
1112 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1113 smallest->next = sorted;
1114 sorted = smallest;
1115 }
1116 list = sorted;
1117 }
1118
1119 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1120 size_t max_alloc_words) {
1121 ScratchBlock* res = NULL;
1122 for (int i = 0; i < _n_gens; i++) {
1123 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1124 }
1125 sort_scratch_list(res);
1126 return res;
1127 }
1128
1129 void GenCollectedHeap::release_scratch() {
1130 for (int i = 0; i < _n_gens; i++) {
1131 _gens[i]->reset_scratch();
1132 }
1133 }
1134
1135 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1136 void do_generation(Generation* gen) {
1137 gen->prepare_for_verify();
1138 }
1139 };
1140
1141 void GenCollectedHeap::prepare_for_verify() {
1142 ensure_parsability(false); // no need to retire TLABs
1143 GenPrepareForVerifyClosure blk;
1144 generation_iterate(&blk, false);
1145 }
1146
1147
1148 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1149 bool old_to_young) {
1150 if (old_to_young) {
1151 for (int i = _n_gens-1; i >= 0; i--) {
1152 cl->do_generation(_gens[i]);
1153 }
1154 } else {
1155 for (int i = 0; i < _n_gens; i++) {
1156 cl->do_generation(_gens[i]);
1157 }
1158 }
1159 }
1160
1161 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1162 for (int i = 0; i < _n_gens; i++) {
1163 _gens[i]->space_iterate(cl, true);
1164 }
1165 }
1166
1167 bool GenCollectedHeap::is_maximal_no_gc() const {
1168 for (int i = 0; i < _n_gens; i++) {
1169 if (!_gens[i]->is_maximal_no_gc()) {
1170 return false;
1171 }
1172 }
1173 return true;
1174 }
1175
1176 void GenCollectedHeap::save_marks() {
1177 for (int i = 0; i < _n_gens; i++) {
1178 _gens[i]->save_marks();
1179 }
1180 }
1181
1182 GenCollectedHeap* GenCollectedHeap::heap() {
1183 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1184 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1185 return _gch;
1186 }
1187
1188
1189 void GenCollectedHeap::prepare_for_compaction() {
1190 guarantee(_n_gens = 2, "Wrong number of generations");
1191 Generation* old_gen = _gens[1];
1192 // Start by compacting into same gen.
1193 CompactPoint cp(old_gen);
1194 old_gen->prepare_for_compaction(&cp);
1195 Generation* young_gen = _gens[0];
1196 young_gen->prepare_for_compaction(&cp);
1197 }
1198
1199 GCStats* GenCollectedHeap::gc_stats(int level) const {
1200 return _gens[level]->gc_stats();
1201 }
1202
1203 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1204 for (int i = _n_gens-1; i >= 0; i--) {
1205 Generation* g = _gens[i];
1206 if (!silent) {
1207 gclog_or_tty->print("%s", g->name());
1208 gclog_or_tty->print(" ");
1209 }
1210 g->verify();
1211 }
1212 if (!silent) {
1213 gclog_or_tty->print("remset ");
1214 }
1215 rem_set()->verify();
1216 }
1217
1218 void GenCollectedHeap::print_on(outputStream* st) const {
1219 for (int i = 0; i < _n_gens; i++) {
1220 _gens[i]->print_on(st);
1221 }
1222 MetaspaceAux::print_on(st);
1223 }
1224
1225 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1226 if (workers() != NULL) {
1227 workers()->threads_do(tc);
1228 }
1229 #if INCLUDE_ALL_GCS
1230 if (UseConcMarkSweepGC) {
1231 ConcurrentMarkSweepThread::threads_do(tc);
1232 }
1233 #endif // INCLUDE_ALL_GCS
1234 }
1235
1236 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1237 #if INCLUDE_ALL_GCS
1238 if (UseParNewGC) {
1239 workers()->print_worker_threads_on(st);
1240 }
1241 if (UseConcMarkSweepGC) {
1242 ConcurrentMarkSweepThread::print_all_on(st);
1243 }
1244 #endif // INCLUDE_ALL_GCS
1245 }
1246
1247 void GenCollectedHeap::print_on_error(outputStream* st) const {
1248 this->CollectedHeap::print_on_error(st);
1249
1250 #if INCLUDE_ALL_GCS
1251 if (UseConcMarkSweepGC) {
1252 st->cr();
1253 CMSCollector::print_on_error(st);
1254 }
1255 #endif // INCLUDE_ALL_GCS
1256 }
1257
1258 void GenCollectedHeap::print_tracing_info() const {
1259 if (TraceGen0Time) {
1260 get_gen(0)->print_summary_info();
1261 }
1262 if (TraceGen1Time) {
1263 get_gen(1)->print_summary_info();
1264 }
1265 }
1266
1267 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1268 if (PrintGCDetails && Verbose) {
1269 gclog_or_tty->print(" " SIZE_FORMAT
1270 "->" SIZE_FORMAT
1271 "(" SIZE_FORMAT ")",
1272 prev_used, used(), capacity());
1273 } else {
1274 gclog_or_tty->print(" " SIZE_FORMAT "K"
1275 "->" SIZE_FORMAT "K"
1276 "(" SIZE_FORMAT "K)",
1277 prev_used / K, used() / K, capacity() / K);
1278 }
1279 }
1280
1281 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1282 private:
1283 bool _full;
1284 public:
1285 void do_generation(Generation* gen) {
1286 gen->gc_prologue(_full);
1287 }
1288 GenGCPrologueClosure(bool full) : _full(full) {};
1289 };
1290
1291 void GenCollectedHeap::gc_prologue(bool full) {
1292 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1293
1294 always_do_update_barrier = false;
1295 // Fill TLAB's and such
1296 CollectedHeap::accumulate_statistics_all_tlabs();
1297 ensure_parsability(true); // retire TLABs
1298
1299 // Walk generations
1300 GenGCPrologueClosure blk(full);
1301 generation_iterate(&blk, false); // not old-to-young.
1302 };
1303
1304 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1305 private:
1306 bool _full;
1307 public:
1308 void do_generation(Generation* gen) {
1309 gen->gc_epilogue(_full);
1310 }
1311 GenGCEpilogueClosure(bool full) : _full(full) {};
1312 };
1313
1314 void GenCollectedHeap::gc_epilogue(bool full) {
1315 #ifdef COMPILER2
1316 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1317 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1318 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1319 #endif /* COMPILER2 */
1320
1321 resize_all_tlabs();
1322
1323 GenGCEpilogueClosure blk(full);
1324 generation_iterate(&blk, false); // not old-to-young.
1325
1326 if (!CleanChunkPoolAsync) {
1327 Chunk::clean_chunk_pool();
1328 }
1329
1330 MetaspaceCounters::update_performance_counters();
1331 CompressedClassSpaceCounters::update_performance_counters();
1332
1333 always_do_update_barrier = UseConcMarkSweepGC;
1334 };
1335
1336 #ifndef PRODUCT
1337 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1338 private:
1339 public:
1340 void do_generation(Generation* gen) {
1341 gen->record_spaces_top();
1342 }
1343 };
1344
1345 void GenCollectedHeap::record_gen_tops_before_GC() {
1346 if (ZapUnusedHeapArea) {
1347 GenGCSaveTopsBeforeGCClosure blk;
1348 generation_iterate(&blk, false); // not old-to-young.
1349 }
1350 }
1351 #endif // not PRODUCT
1352
1353 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1354 public:
1355 void do_generation(Generation* gen) {
1356 gen->ensure_parsability();
1357 }
1358 };
1359
1360 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1361 CollectedHeap::ensure_parsability(retire_tlabs);
1362 GenEnsureParsabilityClosure ep_cl;
1363 generation_iterate(&ep_cl, false);
1364 }
1365
1366 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
1367 oop obj,
1368 size_t obj_size) {
1369 guarantee(old_gen->level() == 1, "We only get here with an old generation");
1370 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1371 HeapWord* result = NULL;
1372
1373 result = old_gen->expand_and_allocate(obj_size, false);
1374
1375 if (result != NULL) {
1376 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1377 }
1378 return oop(result);
1379 }
1380
1381 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1382 jlong _time; // in ms
1383 jlong _now; // in ms
1384
1385 public:
1386 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1387
1388 jlong time() { return _time; }
1389
1390 void do_generation(Generation* gen) {
1391 _time = MIN2(_time, gen->time_of_last_gc(_now));
1392 }
1393 };
1394
1395 jlong GenCollectedHeap::millis_since_last_gc() {
1396 // We need a monotonically non-deccreasing time in ms but
1397 // os::javaTimeMillis() does not guarantee monotonicity.
1398 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1399 GenTimeOfLastGCClosure tolgc_cl(now);
1400 // iterate over generations getting the oldest
1401 // time that a generation was collected
1402 generation_iterate(&tolgc_cl, false);
1403
1404 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1405 // provided the underlying platform provides such a time source
1406 // (and it is bug free). So we still have to guard against getting
1407 // back a time later than 'now'.
1408 jlong retVal = now - tolgc_cl.time();
1409 if (retVal < 0) {
1410 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, (int64_t) retVal);)
1411 return 0;
1412 }
1413 return retVal;
1414 }