1 /*
2 * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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24
25 #ifndef SHARE_GC_G1_G1COLLECTEDHEAP_HPP
26 #define SHARE_GC_G1_G1COLLECTEDHEAP_HPP
27
28 #include "gc/g1/g1BarrierSet.hpp"
29 #include "gc/g1/g1BiasedArray.hpp"
30 #include "gc/g1/g1CardTable.hpp"
31 #include "gc/g1/g1CardSet.hpp"
32 #include "gc/g1/g1CollectionSet.hpp"
33 #include "gc/g1/g1CollectorState.hpp"
34 #include "gc/g1/g1ConcurrentMark.hpp"
35 #include "gc/g1/g1EdenRegions.hpp"
36 #include "gc/g1/g1EvacStats.hpp"
37 #include "gc/g1/g1GCPauseType.hpp"
38 #include "gc/g1/g1HeapRegionAttr.hpp"
39 #include "gc/g1/g1HeapTransition.hpp"
40 #include "gc/g1/g1HeapVerifier.hpp"
41 #include "gc/g1/g1HRPrinter.hpp"
42 #include "gc/g1/g1MonitoringSupport.hpp"
43 #include "gc/g1/g1NUMA.hpp"
44 #include "gc/g1/g1SegmentedArrayFreeMemoryTask.hpp"
45 #include "gc/g1/g1SurvivorRegions.hpp"
46 #include "gc/g1/g1YoungGCEvacFailureInjector.hpp"
47 #include "gc/g1/heapRegionManager.hpp"
48 #include "gc/g1/heapRegionSet.hpp"
49 #include "gc/shared/barrierSet.hpp"
50 #include "gc/shared/collectedHeap.hpp"
51 #include "gc/shared/gcHeapSummary.hpp"
52 #include "gc/shared/plab.hpp"
53 #include "gc/shared/softRefPolicy.hpp"
54 #include "gc/shared/taskqueue.hpp"
55 #include "memory/allocation.hpp"
56 #include "memory/iterator.hpp"
57 #include "memory/memRegion.hpp"
58 #include "utilities/bitMap.hpp"
59
60 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
61 // It uses the "Garbage First" heap organization and algorithm, which
62 // may combine concurrent marking with parallel, incremental compaction of
63 // heap subsets that will yield large amounts of garbage.
64
65 // Forward declarations
66 class G1Allocator;
67 class G1ArchiveAllocator;
68 class G1BatchedTask;
69 class G1CardTableEntryClosure;
70 class G1ConcurrentMark;
71 class G1ConcurrentMarkThread;
72 class G1ConcurrentRefine;
73 class G1GCCounters;
74 class G1GCPhaseTimes;
75 class G1HeapSizingPolicy;
76 class G1HotCardCache;
77 class G1NewTracer;
78 class G1RemSet;
79 class G1ServiceTask;
80 class G1ServiceThread;
81 class GCMemoryManager;
82 class HeapRegion;
83 class MemoryPool;
84 class nmethod;
85 class ReferenceProcessor;
86 class STWGCTimer;
87 class WorkerThreads;
88
89 typedef OverflowTaskQueue<ScannerTask, mtGC> G1ScannerTasksQueue;
90 typedef GenericTaskQueueSet<G1ScannerTasksQueue, mtGC> G1ScannerTasksQueueSet;
91
92 typedef int RegionIdx_t; // needs to hold [ 0..max_reserved_regions() )
93 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
94
95 // The G1 STW is alive closure.
96 // An instance is embedded into the G1CH and used as the
97 // (optional) _is_alive_non_header closure in the STW
98 // reference processor. It is also extensively used during
99 // reference processing during STW evacuation pauses.
100 class G1STWIsAliveClosure : public BoolObjectClosure {
101 G1CollectedHeap* _g1h;
102 public:
103 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
104 bool do_object_b(oop p) override;
105 };
106
107 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure {
108 G1CollectedHeap* _g1h;
109 public:
110 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
111 bool do_object_b(oop p) override;
112 };
113
114 class G1RegionMappingChangedListener : public G1MappingChangedListener {
115 private:
116 void reset_from_card_cache(uint start_idx, size_t num_regions);
117 public:
118 void on_commit(uint start_idx, size_t num_regions, bool zero_filled) override;
119 };
120
121 class G1CollectedHeap : public CollectedHeap {
122 friend class VM_G1CollectForAllocation;
123 friend class VM_G1CollectFull;
124 friend class VM_G1TryInitiateConcMark;
125 friend class VMStructs;
126 friend class MutatorAllocRegion;
127 friend class G1FullCollector;
128 friend class G1GCAllocRegion;
129 friend class G1HeapVerifier;
130
131 friend class G1YoungGCVerifierMark;
132
133 // Closures used in implementation.
134 friend class G1EvacuateRegionsTask;
135 friend class G1PLABAllocator;
136
137 // Other related classes.
138 friend class G1HeapPrinterMark;
139 friend class HeapRegionClaimer;
140
141 // Testing classes.
142 friend class G1CheckRegionAttrTableClosure;
143
144 private:
145 G1ServiceThread* _service_thread;
146 G1ServiceTask* _periodic_gc_task;
147 G1SegmentedArrayFreeMemoryTask* _free_segmented_array_memory_task;
148
149 WorkerThreads* _workers;
150 G1CardTable* _card_table;
151
152 Ticks _collection_pause_end;
153
154 SoftRefPolicy _soft_ref_policy;
155
156 static size_t _humongous_object_threshold_in_words;
157
158 // These sets keep track of old, archive and humongous regions respectively.
159 HeapRegionSet _old_set;
160 HeapRegionSet _archive_set;
161 HeapRegionSet _humongous_set;
162
163 // Young gen memory statistics before GC.
164 G1SegmentedArrayMemoryStats _young_gen_card_set_stats;
165 // Collection set candidates memory statistics after GC.
166 G1SegmentedArrayMemoryStats _collection_set_candidates_card_set_stats;
167
168 // The block offset table for the G1 heap.
169 G1BlockOffsetTable* _bot;
170
171 public:
172 void rebuild_free_region_list();
173 // Start a new incremental collection set for the next pause.
174 void start_new_collection_set();
175
176 void prepare_region_for_full_compaction(HeapRegion* hr);
177
178 private:
179 // Rebuilds the region sets / lists so that they are repopulated to
180 // reflect the contents of the heap. The only exception is the
181 // humongous set which was not torn down in the first place. If
182 // free_list_only is true, it will only rebuild the free list.
183 void rebuild_region_sets(bool free_list_only);
184
185 // Callback for region mapping changed events.
186 G1RegionMappingChangedListener _listener;
187
188 // Handle G1 NUMA support.
189 G1NUMA* _numa;
190
191 // The sequence of all heap regions in the heap.
192 HeapRegionManager _hrm;
193
194 // Manages all allocations with regions except humongous object allocations.
195 G1Allocator* _allocator;
196
197 G1YoungGCEvacFailureInjector _evac_failure_injector;
198
199 // Manages all heap verification.
200 G1HeapVerifier* _verifier;
201
202 // Outside of GC pauses, the number of bytes used in all regions other
203 // than the current allocation region(s).
204 volatile size_t _summary_bytes_used;
205
206 void increase_used(size_t bytes);
207 void decrease_used(size_t bytes);
208
209 void set_used(size_t bytes);
210
211 // Number of bytes used in all regions during GC. Typically changed when
212 // retiring a GC alloc region.
213 size_t _bytes_used_during_gc;
214
215 public:
216 size_t bytes_used_during_gc() const { return _bytes_used_during_gc; }
217
218 private:
219 // Class that handles archive allocation ranges.
220 G1ArchiveAllocator* _archive_allocator;
221
222 // GC allocation statistics policy for survivors.
223 G1EvacStats _survivor_evac_stats;
224
225 // GC allocation statistics policy for tenured objects.
226 G1EvacStats _old_evac_stats;
227
228 // Helper for monitoring and management support.
229 G1MonitoringSupport* _monitoring_support;
230
231 // Records whether the region at the given index is (still) a
232 // candidate for eager reclaim. Only valid for humongous start
233 // regions; other regions have unspecified values. Humongous start
234 // regions are initialized at start of collection pause, with
235 // candidates removed from the set as they are found reachable from
236 // roots or the young generation.
237 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> {
238 protected:
239 bool default_value() const override { return false; }
240 public:
241 void clear() { G1BiasedMappedArray<bool>::clear(); }
242 void set_candidate(uint region, bool value) {
243 set_by_index(region, value);
244 }
245 bool is_candidate(uint region) {
246 return get_by_index(region);
247 }
248 };
249
250 HumongousReclaimCandidates _humongous_reclaim_candidates;
251 uint _num_humongous_objects; // Current amount of (all) humongous objects found in the heap.
252 uint _num_humongous_reclaim_candidates; // Number of humongous object eager reclaim candidates.
253 public:
254 uint num_humongous_objects() const { return _num_humongous_objects; }
255 uint num_humongous_reclaim_candidates() const { return _num_humongous_reclaim_candidates; }
256 bool has_humongous_reclaim_candidates() const { return _num_humongous_reclaim_candidates > 0; }
257
258 bool should_do_eager_reclaim() const;
259
260 void set_humongous_stats(uint num_humongous_total, uint num_humongous_candidates);
261
262 bool should_sample_collection_set_candidates() const;
263 void set_collection_set_candidates_stats(G1SegmentedArrayMemoryStats& stats);
264 void set_young_gen_card_set_stats(const G1SegmentedArrayMemoryStats& stats);
265
266 private:
267
268 G1HRPrinter _hr_printer;
269
270 // Return true if an explicit GC should start a concurrent cycle instead
271 // of doing a STW full GC. A concurrent cycle should be started if:
272 // (a) cause == _g1_humongous_allocation,
273 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent,
274 // (c) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent,
275 // (d) cause == _wb_conc_mark or _wb_breakpoint,
276 // (e) cause == _g1_periodic_collection and +G1PeriodicGCInvokesConcurrent.
277 bool should_do_concurrent_full_gc(GCCause::Cause cause);
278
279 // Attempt to start a concurrent cycle with the indicated cause.
280 // precondition: should_do_concurrent_full_gc(cause)
281 bool try_collect_concurrently(GCCause::Cause cause,
282 uint gc_counter,
283 uint old_marking_started_before);
284
285 // indicates whether we are in young or mixed GC mode
286 G1CollectorState _collector_state;
287
288 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
289 // concurrent cycles) we have started.
290 volatile uint _old_marking_cycles_started;
291
292 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
293 // concurrent cycles) we have completed.
294 volatile uint _old_marking_cycles_completed;
295
296 // This is a non-product method that is helpful for testing. It is
297 // called at the end of a GC and artificially expands the heap by
298 // allocating a number of dead regions. This way we can induce very
299 // frequent marking cycles and stress the cleanup / concurrent
300 // cleanup code more (as all the regions that will be allocated by
301 // this method will be found dead by the marking cycle).
302 void allocate_dummy_regions() PRODUCT_RETURN;
303
304 // Create a memory mapper for auxiliary data structures of the given size and
305 // translation factor.
306 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description,
307 size_t size,
308 size_t translation_factor);
309
310 void trace_heap(GCWhen::Type when, const GCTracer* tracer) override;
311
312 // These are macros so that, if the assert fires, we get the correct
313 // line number, file, etc.
314
315 #define heap_locking_asserts_params(_extra_message_) \
316 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
317 (_extra_message_), \
318 BOOL_TO_STR(Heap_lock->owned_by_self()), \
319 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
320 BOOL_TO_STR(Thread::current()->is_VM_thread())
321
322 #define assert_heap_locked() \
323 do { \
324 assert(Heap_lock->owned_by_self(), \
325 heap_locking_asserts_params("should be holding the Heap_lock")); \
326 } while (0)
327
328 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
329 do { \
330 assert(Heap_lock->owned_by_self() || \
331 (SafepointSynchronize::is_at_safepoint() && \
332 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
333 heap_locking_asserts_params("should be holding the Heap_lock or " \
334 "should be at a safepoint")); \
335 } while (0)
336
337 #define assert_heap_locked_and_not_at_safepoint() \
338 do { \
339 assert(Heap_lock->owned_by_self() && \
340 !SafepointSynchronize::is_at_safepoint(), \
341 heap_locking_asserts_params("should be holding the Heap_lock and " \
342 "should not be at a safepoint")); \
343 } while (0)
344
345 #define assert_heap_not_locked() \
346 do { \
347 assert(!Heap_lock->owned_by_self(), \
348 heap_locking_asserts_params("should not be holding the Heap_lock")); \
349 } while (0)
350
351 #define assert_heap_not_locked_and_not_at_safepoint() \
352 do { \
353 assert(!Heap_lock->owned_by_self() && \
354 !SafepointSynchronize::is_at_safepoint(), \
355 heap_locking_asserts_params("should not be holding the Heap_lock and " \
356 "should not be at a safepoint")); \
357 } while (0)
358
359 #define assert_at_safepoint_on_vm_thread() \
360 do { \
361 assert_at_safepoint(); \
362 assert(Thread::current_or_null() != NULL, "no current thread"); \
363 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \
364 } while (0)
365
366 #ifdef ASSERT
367 #define assert_used_and_recalculate_used_equal(g1h) \
368 do { \
369 size_t cur_used_bytes = g1h->used(); \
370 size_t recal_used_bytes = g1h->recalculate_used(); \
371 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \
372 " same as recalculated used(" SIZE_FORMAT ").", \
373 cur_used_bytes, recal_used_bytes); \
374 } while (0)
375 #else
376 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0)
377 #endif
378
379 // The young region list.
380 G1EdenRegions _eden;
381 G1SurvivorRegions _survivor;
382
383 STWGCTimer* _gc_timer_stw;
384
385 G1NewTracer* _gc_tracer_stw;
386
387 // The current policy object for the collector.
388 G1Policy* _policy;
389 G1HeapSizingPolicy* _heap_sizing_policy;
390
391 G1CollectionSet _collection_set;
392
393 // Try to allocate a single non-humongous HeapRegion sufficient for
394 // an allocation of the given word_size. If do_expand is true,
395 // attempt to expand the heap if necessary to satisfy the allocation
396 // request. 'type' takes the type of region to be allocated. (Use constants
397 // Old, Eden, Humongous, Survivor defined in HeapRegionType.)
398 HeapRegion* new_region(size_t word_size,
399 HeapRegionType type,
400 bool do_expand,
401 uint node_index = G1NUMA::AnyNodeIndex);
402
403 // Initialize a contiguous set of free regions of length num_regions
404 // and starting at index first so that they appear as a single
405 // humongous region.
406 HeapWord* humongous_obj_allocate_initialize_regions(HeapRegion* first_hr,
407 uint num_regions,
408 size_t word_size);
409
410 // Attempt to allocate a humongous object of the given size. Return
411 // NULL if unsuccessful.
412 HeapWord* humongous_obj_allocate(size_t word_size);
413
414 // The following two methods, allocate_new_tlab() and
415 // mem_allocate(), are the two main entry points from the runtime
416 // into the G1's allocation routines. They have the following
417 // assumptions:
418 //
419 // * They should both be called outside safepoints.
420 //
421 // * They should both be called without holding the Heap_lock.
422 //
423 // * All allocation requests for new TLABs should go to
424 // allocate_new_tlab().
425 //
426 // * All non-TLAB allocation requests should go to mem_allocate().
427 //
428 // * If either call cannot satisfy the allocation request using the
429 // current allocating region, they will try to get a new one. If
430 // this fails, they will attempt to do an evacuation pause and
431 // retry the allocation.
432 //
433 // * If all allocation attempts fail, even after trying to schedule
434 // an evacuation pause, allocate_new_tlab() will return NULL,
435 // whereas mem_allocate() will attempt a heap expansion and/or
436 // schedule a Full GC.
437 //
438 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
439 // should never be called with word_size being humongous. All
440 // humongous allocation requests should go to mem_allocate() which
441 // will satisfy them with a special path.
442
443 HeapWord* allocate_new_tlab(size_t min_size,
444 size_t requested_size,
445 size_t* actual_size) override;
446
447 HeapWord* mem_allocate(size_t word_size,
448 bool* gc_overhead_limit_was_exceeded) override;
449
450 // First-level mutator allocation attempt: try to allocate out of
451 // the mutator alloc region without taking the Heap_lock. This
452 // should only be used for non-humongous allocations.
453 inline HeapWord* attempt_allocation(size_t min_word_size,
454 size_t desired_word_size,
455 size_t* actual_word_size);
456
457 // Second-level mutator allocation attempt: take the Heap_lock and
458 // retry the allocation attempt, potentially scheduling a GC
459 // pause. This should only be used for non-humongous allocations.
460 HeapWord* attempt_allocation_slow(size_t word_size);
461
462 // Takes the Heap_lock and attempts a humongous allocation. It can
463 // potentially schedule a GC pause.
464 HeapWord* attempt_allocation_humongous(size_t word_size);
465
466 // Allocation attempt that should be called during safepoints (e.g.,
467 // at the end of a successful GC). expect_null_mutator_alloc_region
468 // specifies whether the mutator alloc region is expected to be NULL
469 // or not.
470 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
471 bool expect_null_mutator_alloc_region);
472
473 // These methods are the "callbacks" from the G1AllocRegion class.
474
475 // For mutator alloc regions.
476 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index);
477 void retire_mutator_alloc_region(HeapRegion* alloc_region,
478 size_t allocated_bytes);
479
480 // For GC alloc regions.
481 bool has_more_regions(G1HeapRegionAttr dest);
482 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest, uint node_index);
483 void retire_gc_alloc_region(HeapRegion* alloc_region,
484 size_t allocated_bytes, G1HeapRegionAttr dest);
485
486 // - if explicit_gc is true, the GC is for a System.gc() etc,
487 // otherwise it's for a failed allocation.
488 // - if clear_all_soft_refs is true, all soft references should be
489 // cleared during the GC.
490 // - if do_maximal_compaction is true, full gc will do a maximally
491 // compacting collection, leaving no dead wood.
492 // - it returns false if it is unable to do the collection due to the
493 // GC locker being active, true otherwise.
494 bool do_full_collection(bool explicit_gc,
495 bool clear_all_soft_refs,
496 bool do_maximal_compaction);
497
498 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
499 void do_full_collection(bool clear_all_soft_refs) override;
500
501 // Helper to do a full collection that clears soft references.
502 bool upgrade_to_full_collection();
503
504 // Callback from VM_G1CollectForAllocation operation.
505 // This function does everything necessary/possible to satisfy a
506 // failed allocation request (including collection, expansion, etc.)
507 HeapWord* satisfy_failed_allocation(size_t word_size,
508 bool* succeeded);
509 // Internal helpers used during full GC to split it up to
510 // increase readability.
511 void abort_concurrent_cycle();
512 void verify_before_full_collection(bool explicit_gc);
513 void prepare_heap_for_full_collection();
514 void prepare_heap_for_mutators();
515 void abort_refinement();
516 void verify_after_full_collection();
517 void print_heap_after_full_collection();
518
519 // Helper method for satisfy_failed_allocation()
520 HeapWord* satisfy_failed_allocation_helper(size_t word_size,
521 bool do_gc,
522 bool maximal_compaction,
523 bool expect_null_mutator_alloc_region,
524 bool* gc_succeeded);
525
526 // Attempting to expand the heap sufficiently
527 // to support an allocation of the given "word_size". If
528 // successful, perform the allocation and return the address of the
529 // allocated block, or else "NULL".
530 HeapWord* expand_and_allocate(size_t word_size);
531
532 void verify_numa_regions(const char* desc);
533
534 public:
535 // If during a concurrent start pause we may install a pending list head which is not
536 // otherwise reachable, ensure that it is marked in the bitmap for concurrent marking
537 // to discover.
538 void make_pending_list_reachable();
539
540 G1ServiceThread* service_thread() const { return _service_thread; }
541
542 WorkerThreads* workers() const { return _workers; }
543
544 // Run the given batch task using the workers.
545 void run_batch_task(G1BatchedTask* cl);
546
547 G1Allocator* allocator() {
548 return _allocator;
549 }
550
551 G1YoungGCEvacFailureInjector* evac_failure_injector() { return &_evac_failure_injector; }
552
553 G1HeapVerifier* verifier() {
554 return _verifier;
555 }
556
557 G1MonitoringSupport* monitoring_support() {
558 assert(_monitoring_support != nullptr, "should have been initialized");
559 return _monitoring_support;
560 }
561
562 void resize_heap_if_necessary();
563
564 // Check if there is memory to uncommit and if so schedule a task to do it.
565 void uncommit_regions_if_necessary();
566 // Immediately uncommit uncommittable regions.
567 uint uncommit_regions(uint region_limit);
568 bool has_uncommittable_regions();
569
570 G1NUMA* numa() const { return _numa; }
571
572 // Expand the garbage-first heap by at least the given size (in bytes!).
573 // Returns true if the heap was expanded by the requested amount;
574 // false otherwise.
575 // (Rounds up to a HeapRegion boundary.)
576 bool expand(size_t expand_bytes, WorkerThreads* pretouch_workers = NULL, double* expand_time_ms = NULL);
577 bool expand_single_region(uint node_index);
578
579 // Returns the PLAB statistics for a given destination.
580 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest);
581
582 // Determines PLAB size for a given destination.
583 inline size_t desired_plab_sz(G1HeapRegionAttr dest);
584
585 // Do anything common to GC's.
586 void gc_prologue(bool full);
587 void gc_epilogue(bool full);
588
589 // Does the given region fulfill remembered set based eager reclaim candidate requirements?
590 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const;
591
592 // Modify the reclaim candidate set and test for presence.
593 // These are only valid for starts_humongous regions.
594 inline void set_humongous_reclaim_candidate(uint region, bool value);
595 inline bool is_humongous_reclaim_candidate(uint region);
596
597 // Remove from the reclaim candidate set. Also remove from the
598 // collection set so that later encounters avoid the slow path.
599 inline void set_humongous_is_live(oop obj);
600
601 // Register the given region to be part of the collection set.
602 inline void register_humongous_region_with_region_attr(uint index);
603
604 // We register a region with the fast "in collection set" test. We
605 // simply set to true the array slot corresponding to this region.
606 void register_young_region_with_region_attr(HeapRegion* r) {
607 _region_attr.set_in_young(r->hrm_index());
608 }
609 inline void register_new_survivor_region_with_region_attr(HeapRegion* r);
610 inline void register_region_with_region_attr(HeapRegion* r);
611 inline void register_old_region_with_region_attr(HeapRegion* r);
612 inline void register_optional_region_with_region_attr(HeapRegion* r);
613
614 void clear_region_attr(const HeapRegion* hr) {
615 _region_attr.clear(hr);
616 }
617
618 void clear_region_attr() {
619 _region_attr.clear();
620 }
621
622 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking
623 // for all regions.
624 void verify_region_attr_remset_is_tracked() PRODUCT_RETURN;
625
626 void clear_prev_bitmap_for_region(HeapRegion* hr);
627
628 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause);
629
630 // This is called at the start of either a concurrent cycle or a Full
631 // GC to update the number of old marking cycles started.
632 void increment_old_marking_cycles_started();
633
634 // This is called at the end of either a concurrent cycle or a Full
635 // GC to update the number of old marking cycles completed. Those two
636 // can happen in a nested fashion, i.e., we start a concurrent
637 // cycle, a Full GC happens half-way through it which ends first,
638 // and then the cycle notices that a Full GC happened and ends
639 // too. The concurrent parameter is a boolean to help us do a bit
640 // tighter consistency checking in the method. If concurrent is
641 // false, the caller is the inner caller in the nesting (i.e., the
642 // Full GC). If concurrent is true, the caller is the outer caller
643 // in this nesting (i.e., the concurrent cycle). Further nesting is
644 // not currently supported. The end of this call also notifies
645 // the G1OldGCCount_lock in case a Java thread is waiting for a full
646 // GC to happen (e.g., it called System.gc() with
647 // +ExplicitGCInvokesConcurrent).
648 // whole_heap_examined should indicate that during that old marking
649 // cycle the whole heap has been examined for live objects (as opposed
650 // to only parts, or aborted before completion).
651 void increment_old_marking_cycles_completed(bool concurrent, bool whole_heap_examined);
652
653 uint old_marking_cycles_started() const {
654 return _old_marking_cycles_started;
655 }
656
657 uint old_marking_cycles_completed() const {
658 return _old_marking_cycles_completed;
659 }
660
661 G1HRPrinter* hr_printer() { return &_hr_printer; }
662
663 // Allocates a new heap region instance.
664 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr);
665
666 // Allocate the highest free region in the reserved heap. This will commit
667 // regions as necessary.
668 HeapRegion* alloc_highest_free_region();
669
670 // Frees a region by resetting its metadata and adding it to the free list
671 // passed as a parameter (this is usually a local list which will be appended
672 // to the master free list later or NULL if free list management is handled
673 // in another way).
674 // Callers must ensure they are the only one calling free on the given region
675 // at the same time.
676 void free_region(HeapRegion* hr, FreeRegionList* free_list);
677
678 // It dirties the cards that cover the block so that the post
679 // write barrier never queues anything when updating objects on this
680 // block. It is assumed (and in fact we assert) that the block
681 // belongs to a young region.
682 inline void dirty_young_block(HeapWord* start, size_t word_size);
683
684 // Frees a humongous region by collapsing it into individual regions
685 // and calling free_region() for each of them. The freed regions
686 // will be added to the free list that's passed as a parameter (this
687 // is usually a local list which will be appended to the master free
688 // list later).
689 // The method assumes that only a single thread is ever calling
690 // this for a particular region at once.
691 void free_humongous_region(HeapRegion* hr,
692 FreeRegionList* free_list);
693
694 // Facility for allocating in 'archive' regions in high heap memory and
695 // recording the allocated ranges. These should all be called from the
696 // VM thread at safepoints, without the heap lock held. They can be used
697 // to create and archive a set of heap regions which can be mapped at the
698 // same fixed addresses in a subsequent JVM invocation.
699 void begin_archive_alloc_range(bool open = false);
700
701 // Check if the requested size would be too large for an archive allocation.
702 bool is_archive_alloc_too_large(size_t word_size);
703
704 // Allocate memory of the requested size from the archive region. This will
705 // return NULL if the size is too large or if no memory is available. It
706 // does not trigger a garbage collection.
707 HeapWord* archive_mem_allocate(size_t word_size);
708
709 // Optionally aligns the end address and returns the allocated ranges in
710 // an array of MemRegions in order of ascending addresses.
711 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges,
712 size_t end_alignment_in_bytes = 0);
713
714 // Facility for allocating a fixed range within the heap and marking
715 // the containing regions as 'archive'. For use at JVM init time, when the
716 // caller may mmap archived heap data at the specified range(s).
717 // Verify that the MemRegions specified in the argument array are within the
718 // reserved heap.
719 bool check_archive_addresses(MemRegion* range, size_t count);
720
721 // Commit the appropriate G1 regions containing the specified MemRegions
722 // and mark them as 'archive' regions. The regions in the array must be
723 // non-overlapping and in order of ascending address.
724 bool alloc_archive_regions(MemRegion* range, size_t count, bool open);
725
726 // Insert any required filler objects in the G1 regions around the specified
727 // ranges to make the regions parseable. This must be called after
728 // alloc_archive_regions, and after class loading has occurred.
729 void fill_archive_regions(MemRegion* range, size_t count);
730
731 // Populate the G1BlockOffsetTablePart for archived regions with the given
732 // memory ranges.
733 void populate_archive_regions_bot_part(MemRegion* range, size_t count);
734
735 // For each of the specified MemRegions, uncommit the containing G1 regions
736 // which had been allocated by alloc_archive_regions. This should be called
737 // rather than fill_archive_regions at JVM init time if the archive file
738 // mapping failed, with the same non-overlapping and sorted MemRegion array.
739 void dealloc_archive_regions(MemRegion* range, size_t count);
740
741 private:
742
743 // Shrink the garbage-first heap by at most the given size (in bytes!).
744 // (Rounds down to a HeapRegion boundary.)
745 void shrink(size_t shrink_bytes);
746 void shrink_helper(size_t expand_bytes);
747
748 // Schedule the VM operation that will do an evacuation pause to
749 // satisfy an allocation request of word_size. *succeeded will
750 // return whether the VM operation was successful (it did do an
751 // evacuation pause) or not (another thread beat us to it or the GC
752 // locker was active). Given that we should not be holding the
753 // Heap_lock when we enter this method, we will pass the
754 // gc_count_before (i.e., total_collections()) as a parameter since
755 // it has to be read while holding the Heap_lock. Currently, both
756 // methods that call do_collection_pause() release the Heap_lock
757 // before the call, so it's easy to read gc_count_before just before.
758 HeapWord* do_collection_pause(size_t word_size,
759 uint gc_count_before,
760 bool* succeeded,
761 GCCause::Cause gc_cause);
762
763 // Perform an incremental collection at a safepoint, possibly
764 // followed by a by-policy upgrade to a full collection. Returns
765 // false if unable to do the collection due to the GC locker being
766 // active, true otherwise.
767 // precondition: at safepoint on VM thread
768 // precondition: !is_gc_active()
769 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
770
771 // Helper for do_collection_pause_at_safepoint, containing the guts
772 // of the incremental collection pause, executed by the vm thread.
773 void do_collection_pause_at_safepoint_helper(double target_pause_time_ms);
774
775 G1HeapVerifier::G1VerifyType young_collection_verify_type() const;
776 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type);
777 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type);
778
779 public:
780 // Start a concurrent cycle.
781 void start_concurrent_cycle(bool concurrent_operation_is_full_mark);
782
783 void prepare_tlabs_for_mutator();
784
785 void retire_tlabs();
786
787 void expand_heap_after_young_collection();
788 // Update object copying statistics.
789 void record_obj_copy_mem_stats();
790
791 private:
792 // The hot card cache for remembered set insertion optimization.
793 G1HotCardCache* _hot_card_cache;
794
795 // The g1 remembered set of the heap.
796 G1RemSet* _rem_set;
797 // Global card set configuration
798 G1CardSetConfiguration _card_set_config;
799
800 public:
801 // After a collection pause, reset eden and the collection set.
802 void clear_eden();
803 void clear_collection_set();
804
805 // Abandon the current collection set without recording policy
806 // statistics or updating free lists.
807 void abandon_collection_set(G1CollectionSet* collection_set);
808
809 // The concurrent marker (and the thread it runs in.)
810 G1ConcurrentMark* _cm;
811 G1ConcurrentMarkThread* _cm_thread;
812
813 // The concurrent refiner.
814 G1ConcurrentRefine* _cr;
815
816 // The parallel task queues
817 G1ScannerTasksQueueSet *_task_queues;
818
819 // ("Weak") Reference processing support.
820 //
821 // G1 has 2 instances of the reference processor class.
822 //
823 // One (_ref_processor_cm) handles reference object discovery and subsequent
824 // processing during concurrent marking cycles. Discovery is enabled/disabled
825 // at the start/end of a concurrent marking cycle.
826 //
827 // The other (_ref_processor_stw) handles reference object discovery and
828 // processing during incremental evacuation pauses and full GC pauses.
829 //
830 // ## Incremental evacuation pauses
831 //
832 // STW ref processor discovery is enabled/disabled at the start/end of an
833 // incremental evacuation pause. No particular handling of the CM ref
834 // processor is needed, apart from treating the discovered references as
835 // roots; CM discovery does not need to be temporarily disabled as all
836 // marking threads are paused during incremental evacuation pauses.
837 //
838 // ## Full GC pauses
839 //
840 // We abort any ongoing concurrent marking cycle, disable CM discovery, and
841 // temporarily substitute a new closure for the STW ref processor's
842 // _is_alive_non_header field (old value is restored after the full GC). Then
843 // STW ref processor discovery is enabled, and marking & compaction
844 // commences.
845
846 // The (stw) reference processor...
847 ReferenceProcessor* _ref_processor_stw;
848
849 // During reference object discovery, the _is_alive_non_header
850 // closure (if non-null) is applied to the referent object to
851 // determine whether the referent is live. If so then the
852 // reference object does not need to be 'discovered' and can
853 // be treated as a regular oop. This has the benefit of reducing
854 // the number of 'discovered' reference objects that need to
855 // be processed.
856 //
857 // Instance of the is_alive closure for embedding into the
858 // STW reference processor as the _is_alive_non_header field.
859 // Supplying a value for the _is_alive_non_header field is
860 // optional but doing so prevents unnecessary additions to
861 // the discovered lists during reference discovery.
862 G1STWIsAliveClosure _is_alive_closure_stw;
863
864 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw;
865
866 // The (concurrent marking) reference processor...
867 ReferenceProcessor* _ref_processor_cm;
868
869 // Instance of the concurrent mark is_alive closure for embedding
870 // into the Concurrent Marking reference processor as the
871 // _is_alive_non_header field. Supplying a value for the
872 // _is_alive_non_header field is optional but doing so prevents
873 // unnecessary additions to the discovered lists during reference
874 // discovery.
875 G1CMIsAliveClosure _is_alive_closure_cm;
876
877 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm;
878 public:
879
880 G1ScannerTasksQueueSet* task_queues() const;
881 G1ScannerTasksQueue* task_queue(uint i) const;
882
883 // Create a G1CollectedHeap.
884 // Must call the initialize method afterwards.
885 // May not return if something goes wrong.
886 G1CollectedHeap();
887
888 private:
889 jint initialize_concurrent_refinement();
890 jint initialize_service_thread();
891 public:
892 // Initialize the G1CollectedHeap to have the initial and
893 // maximum sizes and remembered and barrier sets
894 // specified by the policy object.
895 jint initialize() override;
896
897 // Returns whether concurrent mark threads (and the VM) are about to terminate.
898 bool concurrent_mark_is_terminating() const;
899
900 void stop() override;
901 void safepoint_synchronize_begin() override;
902 void safepoint_synchronize_end() override;
903
904 // Does operations required after initialization has been done.
905 void post_initialize() override;
906
907 // Initialize weak reference processing.
908 void ref_processing_init();
909
910 Name kind() const override {
911 return CollectedHeap::G1;
912 }
913
914 const char* name() const override {
915 return "G1";
916 }
917
918 const G1CollectorState* collector_state() const { return &_collector_state; }
919 G1CollectorState* collector_state() { return &_collector_state; }
920
921 // The current policy object for the collector.
922 G1Policy* policy() const { return _policy; }
923 // The remembered set.
924 G1RemSet* rem_set() const { return _rem_set; }
925
926 inline G1GCPhaseTimes* phase_times() const;
927
928 const G1CollectionSet* collection_set() const { return &_collection_set; }
929 G1CollectionSet* collection_set() { return &_collection_set; }
930
931 SoftRefPolicy* soft_ref_policy() override;
932
933 void initialize_serviceability() override;
934 MemoryUsage memory_usage() override;
935 GrowableArray<GCMemoryManager*> memory_managers() override;
936 GrowableArray<MemoryPool*> memory_pools() override;
937
938 void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) override;
939
940 // Apply the given closure on all cards in the Hot Card Cache, emptying it.
941 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id);
942
943 // The shared block offset table array.
944 G1BlockOffsetTable* bot() const { return _bot; }
945
946 // Reference Processing accessors
947
948 // The STW reference processor....
949 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
950
951 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; }
952 STWGCTimer* gc_timer_stw() const { return _gc_timer_stw; }
953
954 // The Concurrent Marking reference processor...
955 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
956
957 size_t unused_committed_regions_in_bytes() const;
958
959 size_t capacity() const override;
960 size_t used() const override;
961 // This should be called when we're not holding the heap lock. The
962 // result might be a bit inaccurate.
963 size_t used_unlocked() const;
964 size_t recalculate_used() const;
965
966 // These virtual functions do the actual allocation.
967 // Some heaps may offer a contiguous region for shared non-blocking
968 // allocation, via inlined code (by exporting the address of the top and
969 // end fields defining the extent of the contiguous allocation region.)
970 // But G1CollectedHeap doesn't yet support this.
971
972 bool is_maximal_no_gc() const override {
973 return _hrm.available() == 0;
974 }
975
976 // Returns true if an incremental GC should be upgrade to a full gc. This
977 // is done when there are no free regions and the heap can't be expanded.
978 bool should_upgrade_to_full_gc() const {
979 return is_maximal_no_gc() && num_free_regions() == 0;
980 }
981
982 // The current number of regions in the heap.
983 uint num_regions() const { return _hrm.length(); }
984
985 // The max number of regions reserved for the heap. Except for static array
986 // sizing purposes you probably want to use max_regions().
987 uint max_reserved_regions() const { return _hrm.reserved_length(); }
988
989 // Max number of regions that can be committed.
990 uint max_regions() const { return _hrm.max_length(); }
991
992 // The number of regions that are completely free.
993 uint num_free_regions() const { return _hrm.num_free_regions(); }
994
995 // The number of regions that can be allocated into.
996 uint num_free_or_available_regions() const { return num_free_regions() + _hrm.available(); }
997
998 MemoryUsage get_auxiliary_data_memory_usage() const {
999 return _hrm.get_auxiliary_data_memory_usage();
1000 }
1001
1002 // The number of regions that are not completely free.
1003 uint num_used_regions() const { return num_regions() - num_free_regions(); }
1004
1005 #ifdef ASSERT
1006 bool is_on_master_free_list(HeapRegion* hr) {
1007 return _hrm.is_free(hr);
1008 }
1009 #endif // ASSERT
1010
1011 inline void old_set_add(HeapRegion* hr);
1012 inline void old_set_remove(HeapRegion* hr);
1013
1014 inline void archive_set_add(HeapRegion* hr);
1015
1016 size_t non_young_capacity_bytes() {
1017 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes;
1018 }
1019
1020 // Determine whether the given region is one that we are using as an
1021 // old GC alloc region.
1022 bool is_old_gc_alloc_region(HeapRegion* hr);
1023
1024 // Perform a collection of the heap; intended for use in implementing
1025 // "System.gc". This probably implies as full a collection as the
1026 // "CollectedHeap" supports.
1027 void collect(GCCause::Cause cause) override;
1028
1029 // Perform a collection of the heap with the given cause.
1030 // Returns whether this collection actually executed.
1031 bool try_collect(GCCause::Cause cause, const G1GCCounters& counters_before);
1032
1033 void start_concurrent_gc_for_metadata_allocation(GCCause::Cause gc_cause);
1034
1035 void remove_from_old_gen_sets(const uint old_regions_removed,
1036 const uint archive_regions_removed,
1037 const uint humongous_regions_removed);
1038 void prepend_to_freelist(FreeRegionList* list);
1039 void decrement_summary_bytes(size_t bytes);
1040
1041 bool is_in(const void* p) const override;
1042
1043 // Return "TRUE" iff the given object address is within the collection
1044 // set. Assumes that the reference points into the heap.
1045 inline bool is_in_cset(const HeapRegion *hr);
1046 inline bool is_in_cset(oop obj);
1047 inline bool is_in_cset(HeapWord* addr);
1048
1049 inline bool is_in_cset_or_humongous(const oop obj);
1050
1051 private:
1052 // This array is used for a quick test on whether a reference points into
1053 // the collection set or not. Each of the array's elements denotes whether the
1054 // corresponding region is in the collection set or not.
1055 G1HeapRegionAttrBiasedMappedArray _region_attr;
1056
1057 public:
1058
1059 inline G1HeapRegionAttr region_attr(const void* obj) const;
1060 inline G1HeapRegionAttr region_attr(uint idx) const;
1061
1062 MemRegion reserved() const {
1063 return _hrm.reserved();
1064 }
1065
1066 bool is_in_reserved(const void* addr) const {
1067 return reserved().contains(addr);
1068 }
1069
1070 G1HotCardCache* hot_card_cache() const { return _hot_card_cache; }
1071
1072 G1CardTable* card_table() const {
1073 return _card_table;
1074 }
1075
1076 // Iteration functions.
1077
1078 void object_iterate_parallel(ObjectClosure* cl, uint worker_id, HeapRegionClaimer* claimer);
1079
1080 // Iterate over all objects, calling "cl.do_object" on each.
1081 void object_iterate(ObjectClosure* cl) override;
1082
1083 ParallelObjectIteratorImpl* parallel_object_iterator(uint thread_num) override;
1084
1085 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1086 void keep_alive(oop obj) override;
1087
1088 // Iterate over heap regions, in address order, terminating the
1089 // iteration early if the "do_heap_region" method returns "true".
1090 void heap_region_iterate(HeapRegionClosure* blk) const;
1091
1092 // Return the region with the given index. It assumes the index is valid.
1093 inline HeapRegion* region_at(uint index) const;
1094 inline HeapRegion* region_at_or_null(uint index) const;
1095
1096 // Return the next region (by index) that is part of the same
1097 // humongous object that hr is part of.
1098 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
1099
1100 // Calculate the region index of the given address. Given address must be
1101 // within the heap.
1102 inline uint addr_to_region(HeapWord* addr) const;
1103
1104 inline HeapWord* bottom_addr_for_region(uint index) const;
1105
1106 // Two functions to iterate over the heap regions in parallel. Threads
1107 // compete using the HeapRegionClaimer to claim the regions before
1108 // applying the closure on them.
1109 // The _from_worker_offset version uses the HeapRegionClaimer and
1110 // the worker id to calculate a start offset to prevent all workers to
1111 // start from the point.
1112 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl,
1113 HeapRegionClaimer* hrclaimer,
1114 uint worker_id) const;
1115
1116 void heap_region_par_iterate_from_start(HeapRegionClosure* cl,
1117 HeapRegionClaimer* hrclaimer) const;
1118
1119 // Iterate over all regions in the collection set in parallel.
1120 void collection_set_par_iterate_all(HeapRegionClosure* cl,
1121 HeapRegionClaimer* hr_claimer,
1122 uint worker_id);
1123
1124 // Iterate over all regions currently in the current collection set.
1125 void collection_set_iterate_all(HeapRegionClosure* blk);
1126
1127 // Iterate over the regions in the current increment of the collection set.
1128 // Starts the iteration so that the start regions of a given worker id over the
1129 // set active_workers are evenly spread across the set of collection set regions
1130 // to be iterated.
1131 // The variant with the HeapRegionClaimer guarantees that the closure will be
1132 // applied to a particular region exactly once.
1133 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) {
1134 collection_set_iterate_increment_from(blk, NULL, worker_id);
1135 }
1136 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id);
1137 // Iterate over the array of region indexes, uint regions[length], applying
1138 // the given HeapRegionClosure on each region. The worker_id will determine where
1139 // to start the iteration to allow for more efficient parallel iteration.
1140 void par_iterate_regions_array(HeapRegionClosure* cl,
1141 HeapRegionClaimer* hr_claimer,
1142 const uint regions[],
1143 size_t length,
1144 uint worker_id) const;
1145
1146 // Returns the HeapRegion that contains addr. addr must not be NULL.
1147 template <class T>
1148 inline HeapRegion* heap_region_containing(const T addr) const;
1149
1150 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted
1151 // region. addr must not be NULL.
1152 template <class T>
1153 inline HeapRegion* heap_region_containing_or_null(const T addr) const;
1154
1155 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1156 // each address in the (reserved) heap is a member of exactly
1157 // one block. The defining characteristic of a block is that it is
1158 // possible to find its size, and thus to progress forward to the next
1159 // block. (Blocks may be of different sizes.) Thus, blocks may
1160 // represent Java objects, or they might be free blocks in a
1161 // free-list-based heap (or subheap), as long as the two kinds are
1162 // distinguishable and the size of each is determinable.
1163
1164 // Returns the address of the start of the "block" that contains the
1165 // address "addr". We say "blocks" instead of "object" since some heaps
1166 // may not pack objects densely; a chunk may either be an object or a
1167 // non-object.
1168 HeapWord* block_start(const void* addr) const;
1169
1170 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1171 // the block is an object.
1172 bool block_is_obj(const HeapWord* addr) const;
1173
1174 // Section on thread-local allocation buffers (TLABs)
1175 // See CollectedHeap for semantics.
1176
1177 size_t tlab_capacity(Thread* ignored) const override;
1178 size_t tlab_used(Thread* ignored) const override;
1179 size_t max_tlab_size() const override;
1180 size_t unsafe_max_tlab_alloc(Thread* ignored) const override;
1181
1182 inline bool is_in_young(const oop obj) const;
1183
1184 // Returns "true" iff the given word_size is "very large".
1185 static bool is_humongous(size_t word_size) {
1186 // Note this has to be strictly greater-than as the TLABs
1187 // are capped at the humongous threshold and we want to
1188 // ensure that we don't try to allocate a TLAB as
1189 // humongous and that we don't allocate a humongous
1190 // object in a TLAB.
1191 return word_size > _humongous_object_threshold_in_words;
1192 }
1193
1194 // Returns the humongous threshold for a specific region size
1195 static size_t humongous_threshold_for(size_t region_size) {
1196 return (region_size / 2);
1197 }
1198
1199 // Returns the number of regions the humongous object of the given word size
1200 // requires.
1201 static size_t humongous_obj_size_in_regions(size_t word_size);
1202
1203 // Print the maximum heap capacity.
1204 size_t max_capacity() const override;
1205
1206 Tickspan time_since_last_collection() const { return Ticks::now() - _collection_pause_end; }
1207
1208 // Convenience function to be used in situations where the heap type can be
1209 // asserted to be this type.
1210 static G1CollectedHeap* heap() {
1211 return named_heap<G1CollectedHeap>(CollectedHeap::G1);
1212 }
1213
1214 void set_region_short_lived_locked(HeapRegion* hr);
1215 // add appropriate methods for any other surv rate groups
1216
1217 G1SurvivorRegions* survivor() { return &_survivor; }
1218
1219 uint eden_regions_count() const { return _eden.length(); }
1220 uint eden_regions_count(uint node_index) const { return _eden.regions_on_node(node_index); }
1221 uint survivor_regions_count() const { return _survivor.length(); }
1222 uint survivor_regions_count(uint node_index) const { return _survivor.regions_on_node(node_index); }
1223 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); }
1224 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); }
1225 uint young_regions_count() const { return _eden.length() + _survivor.length(); }
1226 uint old_regions_count() const { return _old_set.length(); }
1227 uint archive_regions_count() const { return _archive_set.length(); }
1228 uint humongous_regions_count() const { return _humongous_set.length(); }
1229
1230 #ifdef ASSERT
1231 bool check_young_list_empty();
1232 #endif
1233
1234 bool is_marked_next(oop obj) const;
1235
1236 // Determine if an object is dead, given the object and also
1237 // the region to which the object belongs.
1238 inline bool is_obj_dead(const oop obj, const HeapRegion* hr) const;
1239
1240 // Determine if an object is dead, given only the object itself.
1241 // This will find the region to which the object belongs and
1242 // then call the region version of the same function.
1243
1244 // Added if it is NULL it isn't dead.
1245
1246 inline bool is_obj_dead(const oop obj) const;
1247
1248 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const;
1249 inline bool is_obj_dead_full(const oop obj) const;
1250
1251 // Mark the live object that failed evacuation in the prev bitmap.
1252 void mark_evac_failure_object(const oop obj, uint worker_id) const;
1253
1254 G1ConcurrentMark* concurrent_mark() const { return _cm; }
1255
1256 // Refinement
1257
1258 G1ConcurrentRefine* concurrent_refine() const { return _cr; }
1259
1260 // Optimized nmethod scanning support routines
1261
1262 // Register the given nmethod with the G1 heap.
1263 void register_nmethod(nmethod* nm) override;
1264
1265 // Unregister the given nmethod from the G1 heap.
1266 void unregister_nmethod(nmethod* nm) override;
1267
1268 // No nmethod flushing needed.
1269 void flush_nmethod(nmethod* nm) override {}
1270
1271 // No nmethod verification implemented.
1272 void verify_nmethod(nmethod* nm) override {}
1273
1274 // Recalculate amount of used memory after GC. Must be called after all allocation
1275 // has finished.
1276 void update_used_after_gc(bool evacuation_failed);
1277 // Reset and re-enable the hot card cache.
1278 // Note the counts for the cards in the regions in the
1279 // collection set are reset when the collection set is freed.
1280 void reset_hot_card_cache();
1281 // Free up superfluous code root memory.
1282 void purge_code_root_memory();
1283
1284 // Rebuild the code root lists for each region
1285 // after a full GC.
1286 void rebuild_code_roots();
1287
1288 // Performs cleaning of data structures after class unloading.
1289 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred);
1290
1291 // Verification
1292
1293 // Perform any cleanup actions necessary before allowing a verification.
1294 void prepare_for_verify() override;
1295
1296 // Perform verification.
1297
1298 // vo == UsePrevMarking -> use "prev" marking information,
1299 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
1300 //
1301 // NOTE: Only the "prev" marking information is guaranteed to be
1302 // consistent most of the time, so most calls to this should use
1303 // vo == UsePrevMarking.
1304 // Currently there is only one place where this is called with
1305 // vo == UseFullMarking, which is to verify the marking during a
1306 // full GC.
1307 void verify(VerifyOption vo) override;
1308
1309 // WhiteBox testing support.
1310 bool supports_concurrent_gc_breakpoints() const override;
1311
1312 WorkerThreads* safepoint_workers() override { return _workers; }
1313
1314 bool is_archived_object(oop object) const override;
1315
1316 // The methods below are here for convenience and dispatch the
1317 // appropriate method depending on value of the given VerifyOption
1318 // parameter. The values for that parameter, and their meanings,
1319 // are the same as those above.
1320
1321 bool is_obj_dead_cond(const oop obj,
1322 const HeapRegion* hr,
1323 const VerifyOption vo) const;
1324
1325 bool is_obj_dead_cond(const oop obj,
1326 const VerifyOption vo) const;
1327
1328 G1HeapSummary create_g1_heap_summary();
1329 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats);
1330
1331 // Printing
1332 private:
1333 void print_heap_regions() const;
1334 void print_regions_on(outputStream* st) const;
1335
1336 public:
1337 void print_on(outputStream* st) const override;
1338 void print_extended_on(outputStream* st) const override;
1339 void print_on_error(outputStream* st) const override;
1340
1341 void gc_threads_do(ThreadClosure* tc) const override;
1342
1343 // Override
1344 void print_tracing_info() const override;
1345
1346 // The following two methods are helpful for debugging RSet issues.
1347 void print_cset_rsets() PRODUCT_RETURN;
1348 void print_all_rsets() PRODUCT_RETURN;
1349
1350 // Used to print information about locations in the hs_err file.
1351 bool print_location(outputStream* st, void* addr) const override;
1352 };
1353
1354 // Scoped object that performs common pre- and post-gc heap printing operations.
1355 class G1HeapPrinterMark : public StackObj {
1356 G1CollectedHeap* _g1h;
1357 G1HeapTransition _heap_transition;
1358
1359 public:
1360 G1HeapPrinterMark(G1CollectedHeap* g1h);
1361 ~G1HeapPrinterMark();
1362 };
1363
1364 // Scoped object that performs common pre- and post-gc operations related to
1365 // JFR events.
1366 class G1JFRTracerMark : public StackObj {
1367 protected:
1368 STWGCTimer* _timer;
1369 GCTracer* _tracer;
1370
1371 public:
1372 G1JFRTracerMark(STWGCTimer* timer, GCTracer* tracer);
1373 ~G1JFRTracerMark();
1374 };
1375
1376 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP