1 /*
2 * Copyright (c) 2001, 2023, 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/g1MonotonicArenaFreeMemoryTask.hpp"
44 #include "gc/g1/g1MonotonicArenaFreePool.hpp"
45 #include "gc/g1/g1NUMA.hpp"
46 #include "gc/g1/g1SurvivorRegions.hpp"
47 #include "gc/g1/g1YoungGCEvacFailureInjector.hpp"
48 #include "gc/g1/heapRegionManager.hpp"
49 #include "gc/g1/heapRegionSet.hpp"
50 #include "gc/shared/barrierSet.hpp"
51 #include "gc/shared/collectedHeap.hpp"
52 #include "gc/shared/gcHeapSummary.hpp"
53 #include "gc/shared/plab.hpp"
54 #include "gc/shared/softRefPolicy.hpp"
55 #include "gc/shared/taskqueue.hpp"
56 #include "memory/allocation.hpp"
57 #include "memory/iterator.hpp"
58 #include "memory/memRegion.hpp"
59 #include "runtime/mutexLocker.hpp"
60 #include "runtime/threadSMR.hpp"
61 #include "utilities/bitMap.hpp"
62
63 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
64 // It uses the "Garbage First" heap organization and algorithm, which
65 // may combine concurrent marking with parallel, incremental compaction of
66 // heap subsets that will yield large amounts of garbage.
67
68 // Forward declarations
69 class G1Allocator;
70 class G1BatchedTask;
71 class G1CardTableEntryClosure;
72 class G1ConcurrentMark;
73 class G1ConcurrentMarkThread;
74 class G1ConcurrentRefine;
75 class G1GCCounters;
76 class G1GCPhaseTimes;
77 class G1HeapSizingPolicy;
78 class G1NewTracer;
79 class G1RemSet;
80 class G1ServiceTask;
81 class G1ServiceThread;
82 class GCMemoryManager;
83 class HeapRegion;
84 class MemoryPool;
85 class nmethod;
86 class ReferenceProcessor;
87 class STWGCTimer;
88 class SlidingForwarding;
89 class WorkerThreads;
90
91 typedef OverflowTaskQueue<ScannerTask, mtGC> G1ScannerTasksQueue;
92 typedef GenericTaskQueueSet<G1ScannerTasksQueue, mtGC> G1ScannerTasksQueueSet;
93
94 typedef int RegionIdx_t; // needs to hold [ 0..max_reserved_regions() )
95 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
96
97 // The G1 STW is alive closure.
98 // An instance is embedded into the G1CH and used as the
99 // (optional) _is_alive_non_header closure in the STW
100 // reference processor. It is also extensively used during
101 // reference processing during STW evacuation pauses.
102 class G1STWIsAliveClosure : public BoolObjectClosure {
103 G1CollectedHeap* _g1h;
104 public:
105 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
106 bool do_object_b(oop p) override;
107 };
108
109 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure {
110 G1CollectedHeap* _g1h;
111 public:
112 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
113 bool do_object_b(oop p) override;
114 };
115
116 class G1RegionMappingChangedListener : public G1MappingChangedListener {
117 private:
118 void reset_from_card_cache(uint start_idx, size_t num_regions);
119 public:
120 void on_commit(uint start_idx, size_t num_regions, bool zero_filled) override;
121 };
122
123 // Helper to claim contiguous sets of JavaThread for processing by multiple threads.
124 class G1JavaThreadsListClaimer : public StackObj {
125 ThreadsListHandle _list;
126 uint _claim_step;
127
128 volatile uint _cur_claim;
129
130 // Attempts to claim _claim_step JavaThreads, returning an array of claimed
131 // JavaThread* with count elements. Returns null (and a zero count) if there
132 // are no more threads to claim.
133 JavaThread* const* claim(uint& count);
134
135 public:
136 G1JavaThreadsListClaimer(uint claim_step) : _list(), _claim_step(claim_step), _cur_claim(0) {
137 assert(claim_step > 0, "must be");
138 }
139
140 // Executes the given closure on the elements of the JavaThread list, chunking the
141 // JavaThread set in claim_step chunks for each caller to reduce parallelization
142 // overhead.
143 void apply(ThreadClosure* cl);
144
145 // Total number of JavaThreads that can be claimed.
146 uint length() const { return _list.length(); }
147 };
148
149 class G1CollectedHeap : public CollectedHeap {
150 friend class VM_G1CollectForAllocation;
151 friend class VM_G1CollectFull;
152 friend class VM_G1TryInitiateConcMark;
153 friend class VMStructs;
154 friend class MutatorAllocRegion;
155 friend class G1FullCollector;
156 friend class G1GCAllocRegion;
157 friend class G1HeapVerifier;
158
159 friend class G1YoungGCVerifierMark;
160
161 // Closures used in implementation.
162 friend class G1EvacuateRegionsTask;
163 friend class G1PLABAllocator;
164
165 // Other related classes.
166 friend class G1HeapPrinterMark;
167 friend class HeapRegionClaimer;
168
169 // Testing classes.
170 friend class G1CheckRegionAttrTableClosure;
171
172 private:
173 G1ServiceThread* _service_thread;
174 G1ServiceTask* _periodic_gc_task;
175 G1MonotonicArenaFreeMemoryTask* _free_arena_memory_task;
176
177 WorkerThreads* _workers;
178 G1CardTable* _card_table;
179
180 Ticks _collection_pause_end;
181
182 SoftRefPolicy _soft_ref_policy;
183
184 static size_t _humongous_object_threshold_in_words;
185
186 // These sets keep track of old, archive and humongous regions respectively.
187 HeapRegionSet _old_set;
188 HeapRegionSet _archive_set;
189 HeapRegionSet _humongous_set;
190
191 // Young gen memory statistics before GC.
192 G1MonotonicArenaMemoryStats _young_gen_card_set_stats;
193 // Collection set candidates memory statistics after GC.
194 G1MonotonicArenaMemoryStats _collection_set_candidates_card_set_stats;
195
196 // The block offset table for the G1 heap.
197 G1BlockOffsetTable* _bot;
198
199 public:
200 void rebuild_free_region_list();
201 // Start a new incremental collection set for the next pause.
202 void start_new_collection_set();
203
204 void prepare_region_for_full_compaction(HeapRegion* hr);
205
206 private:
207 // Rebuilds the region sets / lists so that they are repopulated to
208 // reflect the contents of the heap. The only exception is the
209 // humongous set which was not torn down in the first place. If
210 // free_list_only is true, it will only rebuild the free list.
211 void rebuild_region_sets(bool free_list_only);
212
213 // Callback for region mapping changed events.
214 G1RegionMappingChangedListener _listener;
215
216 // Handle G1 NUMA support.
217 G1NUMA* _numa;
218
219 // The sequence of all heap regions in the heap.
220 HeapRegionManager _hrm;
221
222 // Manages all allocations with regions except humongous object allocations.
223 G1Allocator* _allocator;
224
225 G1YoungGCEvacFailureInjector _evac_failure_injector;
226
227 // Manages all heap verification.
228 G1HeapVerifier* _verifier;
229
230 // Outside of GC pauses, the number of bytes used in all regions other
231 // than the current allocation region(s).
232 volatile size_t _summary_bytes_used;
233
234 void increase_used(size_t bytes);
235 void decrease_used(size_t bytes);
236
237 void set_used(size_t bytes);
238
239 // Number of bytes used in all regions during GC. Typically changed when
240 // retiring a GC alloc region.
241 size_t _bytes_used_during_gc;
242
243 public:
244 size_t bytes_used_during_gc() const { return _bytes_used_during_gc; }
245
246 private:
247 // GC allocation statistics policy for survivors.
248 G1EvacStats _survivor_evac_stats;
249
250 // GC allocation statistics policy for tenured objects.
251 G1EvacStats _old_evac_stats;
252
253 // Helper for monitoring and management support.
254 G1MonitoringSupport* _monitoring_support;
255
256 SlidingForwarding* _forwarding;
257
258 uint _num_humongous_objects; // Current amount of (all) humongous objects found in the heap.
259 uint _num_humongous_reclaim_candidates; // Number of humongous object eager reclaim candidates.
260 public:
261 uint num_humongous_objects() const { return _num_humongous_objects; }
262 uint num_humongous_reclaim_candidates() const { return _num_humongous_reclaim_candidates; }
263 bool has_humongous_reclaim_candidates() const { return _num_humongous_reclaim_candidates > 0; }
264
265 void set_humongous_stats(uint num_humongous_total, uint num_humongous_candidates);
266
267 bool should_sample_collection_set_candidates() const;
268 void set_collection_set_candidates_stats(G1MonotonicArenaMemoryStats& stats);
269 void set_young_gen_card_set_stats(const G1MonotonicArenaMemoryStats& stats);
270
271 SlidingForwarding* forwarding() const {
272 return _forwarding;
273 }
274
275 private:
276
277 G1HRPrinter _hr_printer;
278
279 // Return true if an explicit GC should start a concurrent cycle instead
280 // of doing a STW full GC. A concurrent cycle should be started if:
281 // (a) cause == _g1_humongous_allocation,
282 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent,
283 // (c) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent,
284 // (d) cause == _wb_breakpoint,
285 // (e) cause == _g1_periodic_collection and +G1PeriodicGCInvokesConcurrent.
286 bool should_do_concurrent_full_gc(GCCause::Cause cause);
287
288 // Attempt to start a concurrent cycle with the indicated cause.
289 // precondition: should_do_concurrent_full_gc(cause)
290 bool try_collect_concurrently(GCCause::Cause cause,
291 uint gc_counter,
292 uint old_marking_started_before);
293
294 // indicates whether we are in young or mixed GC mode
295 G1CollectorState _collector_state;
296
297 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
298 // concurrent cycles) we have started.
299 volatile uint _old_marking_cycles_started;
300
301 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
302 // concurrent cycles) we have completed.
303 volatile uint _old_marking_cycles_completed;
304
305 // Create a memory mapper for auxiliary data structures of the given size and
306 // translation factor.
307 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description,
308 size_t size,
309 size_t translation_factor);
310
311 void trace_heap(GCWhen::Type when, const GCTracer* tracer) override;
312
313 // These are macros so that, if the assert fires, we get the correct
314 // line number, file, etc.
315
316 #define heap_locking_asserts_params(_extra_message_) \
317 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
318 (_extra_message_), \
319 BOOL_TO_STR(Heap_lock->owned_by_self()), \
320 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
321 BOOL_TO_STR(Thread::current()->is_VM_thread())
322
323 #define assert_heap_locked() \
324 do { \
325 assert(Heap_lock->owned_by_self(), \
326 heap_locking_asserts_params("should be holding the Heap_lock")); \
327 } while (0)
328
329 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
330 do { \
331 assert(Heap_lock->owned_by_self() || \
332 (SafepointSynchronize::is_at_safepoint() && \
333 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
334 heap_locking_asserts_params("should be holding the Heap_lock or " \
335 "should be at a safepoint")); \
336 } while (0)
337
338 #define assert_heap_locked_and_not_at_safepoint() \
339 do { \
340 assert(Heap_lock->owned_by_self() && \
341 !SafepointSynchronize::is_at_safepoint(), \
342 heap_locking_asserts_params("should be holding the Heap_lock and " \
343 "should not be at a safepoint")); \
344 } while (0)
345
346 #define assert_heap_not_locked() \
347 do { \
348 assert(!Heap_lock->owned_by_self(), \
349 heap_locking_asserts_params("should not be holding the Heap_lock")); \
350 } while (0)
351
352 #define assert_heap_not_locked_and_not_at_safepoint() \
353 do { \
354 assert(!Heap_lock->owned_by_self() && \
355 !SafepointSynchronize::is_at_safepoint(), \
356 heap_locking_asserts_params("should not be holding the Heap_lock and " \
357 "should not be at a safepoint")); \
358 } while (0)
359
360 #define assert_at_safepoint_on_vm_thread() \
361 do { \
362 assert_at_safepoint(); \
363 assert(Thread::current_or_null() != NULL, "no current thread"); \
364 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \
365 } while (0)
366
367 #ifdef ASSERT
368 #define assert_used_and_recalculate_used_equal(g1h) \
369 do { \
370 size_t cur_used_bytes = g1h->used(); \
371 size_t recal_used_bytes = g1h->recalculate_used(); \
372 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \
373 " same as recalculated used(" SIZE_FORMAT ").", \
374 cur_used_bytes, recal_used_bytes); \
375 } while (0)
376 #else
377 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0)
378 #endif
379
380 // The young region list.
381 G1EdenRegions _eden;
382 G1SurvivorRegions _survivor;
383
384 STWGCTimer* _gc_timer_stw;
385
386 G1NewTracer* _gc_tracer_stw;
387
388 // The current policy object for the collector.
389 G1Policy* _policy;
390 G1HeapSizingPolicy* _heap_sizing_policy;
391
392 G1CollectionSet _collection_set;
393
394 // Try to allocate a single non-humongous HeapRegion sufficient for
395 // an allocation of the given word_size. If do_expand is true,
396 // attempt to expand the heap if necessary to satisfy the allocation
397 // request. 'type' takes the type of region to be allocated. (Use constants
398 // Old, Eden, Humongous, Survivor defined in HeapRegionType.)
399 HeapRegion* new_region(size_t word_size,
400 HeapRegionType type,
401 bool do_expand,
402 uint node_index = G1NUMA::AnyNodeIndex);
403
404 // Initialize a contiguous set of free regions of length num_regions
405 // and starting at index first so that they appear as a single
406 // humongous region.
407 HeapWord* humongous_obj_allocate_initialize_regions(HeapRegion* first_hr,
408 uint num_regions,
409 size_t word_size);
410
411 // Attempt to allocate a humongous object of the given size. Return
412 // NULL if unsuccessful.
413 HeapWord* humongous_obj_allocate(size_t word_size);
414
415 // The following two methods, allocate_new_tlab() and
416 // mem_allocate(), are the two main entry points from the runtime
417 // into the G1's allocation routines. They have the following
418 // assumptions:
419 //
420 // * They should both be called outside safepoints.
421 //
422 // * They should both be called without holding the Heap_lock.
423 //
424 // * All allocation requests for new TLABs should go to
425 // allocate_new_tlab().
426 //
427 // * All non-TLAB allocation requests should go to mem_allocate().
428 //
429 // * If either call cannot satisfy the allocation request using the
430 // current allocating region, they will try to get a new one. If
431 // this fails, they will attempt to do an evacuation pause and
432 // retry the allocation.
433 //
434 // * If all allocation attempts fail, even after trying to schedule
435 // an evacuation pause, allocate_new_tlab() will return NULL,
436 // whereas mem_allocate() will attempt a heap expansion and/or
437 // schedule a Full GC.
438 //
439 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
440 // should never be called with word_size being humongous. All
441 // humongous allocation requests should go to mem_allocate() which
442 // will satisfy them with a special path.
443
444 HeapWord* allocate_new_tlab(size_t min_size,
445 size_t requested_size,
446 size_t* actual_size) override;
447
448 HeapWord* mem_allocate(size_t word_size,
449 bool* gc_overhead_limit_was_exceeded) override;
450
451 // First-level mutator allocation attempt: try to allocate out of
452 // the mutator alloc region without taking the Heap_lock. This
453 // should only be used for non-humongous allocations.
454 inline HeapWord* attempt_allocation(size_t min_word_size,
455 size_t desired_word_size,
456 size_t* actual_word_size);
457
458 // Second-level mutator allocation attempt: take the Heap_lock and
459 // retry the allocation attempt, potentially scheduling a GC
460 // pause. This should only be used for non-humongous allocations.
461 HeapWord* attempt_allocation_slow(size_t word_size);
462
463 // Takes the Heap_lock and attempts a humongous allocation. It can
464 // potentially schedule a GC pause.
465 HeapWord* attempt_allocation_humongous(size_t word_size);
466
467 // Allocation attempt that should be called during safepoints (e.g.,
468 // at the end of a successful GC). expect_null_mutator_alloc_region
469 // specifies whether the mutator alloc region is expected to be NULL
470 // or not.
471 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
472 bool expect_null_mutator_alloc_region);
473
474 // These methods are the "callbacks" from the G1AllocRegion class.
475
476 // For mutator alloc regions.
477 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index);
478 void retire_mutator_alloc_region(HeapRegion* alloc_region,
479 size_t allocated_bytes);
480
481 // For GC alloc regions.
482 bool has_more_regions(G1HeapRegionAttr dest);
483 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest, uint node_index);
484 void retire_gc_alloc_region(HeapRegion* alloc_region,
485 size_t allocated_bytes, G1HeapRegionAttr dest);
486
487 // - if explicit_gc is true, the GC is for a System.gc() etc,
488 // otherwise it's for a failed allocation.
489 // - if clear_all_soft_refs is true, all soft references should be
490 // cleared during the GC.
491 // - if do_maximal_compaction is true, full gc will do a maximally
492 // compacting collection, leaving no dead wood.
493 // - it returns false if it is unable to do the collection due to the
494 // GC locker being active, true otherwise.
495 bool do_full_collection(bool explicit_gc,
496 bool clear_all_soft_refs,
497 bool do_maximal_compaction);
498
499 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
500 void do_full_collection(bool clear_all_soft_refs) override;
501
502 // Helper to do a full collection that clears soft references.
503 bool upgrade_to_full_collection();
504
505 // Callback from VM_G1CollectForAllocation operation.
506 // This function does everything necessary/possible to satisfy a
507 // failed allocation request (including collection, expansion, etc.)
508 HeapWord* satisfy_failed_allocation(size_t word_size,
509 bool* succeeded);
510 // Internal helpers used during full GC to split it up to
511 // increase readability.
512 bool abort_concurrent_cycle();
513 void verify_before_full_collection(bool explicit_gc);
514 void prepare_heap_for_full_collection();
515 void prepare_for_mutator_after_full_collection();
516 void abort_refinement();
517 void verify_after_full_collection();
518 void print_heap_after_full_collection();
519
520 // Helper method for satisfy_failed_allocation()
521 HeapWord* satisfy_failed_allocation_helper(size_t word_size,
522 bool do_gc,
523 bool maximal_compaction,
524 bool expect_null_mutator_alloc_region,
525 bool* gc_succeeded);
526
527 // Attempting to expand the heap sufficiently
528 // to support an allocation of the given "word_size". If
529 // successful, perform the allocation and return the address of the
530 // allocated block, or else "NULL".
531 HeapWord* expand_and_allocate(size_t word_size);
532
533 void verify_numa_regions(const char* desc);
534
535 public:
536 // If during a concurrent start pause we may install a pending list head which is not
537 // otherwise reachable, ensure that it is marked in the bitmap for concurrent marking
538 // to discover.
539 void make_pending_list_reachable();
540
541 G1ServiceThread* service_thread() const { return _service_thread; }
542
543 WorkerThreads* workers() const { return _workers; }
544
545 // Run the given batch task using the workers.
546 void run_batch_task(G1BatchedTask* cl);
547
548 // Return "optimal" number of chunks per region we want to use for claiming areas
549 // within a region to claim.
550 // The returned value is a trade-off between granularity of work distribution and
551 // memory usage and maintenance costs of that table.
552 // Testing showed that 64 for 1M/2M region, 128 for 4M/8M regions, 256 for 16/32M regions,
553 // and so on seems to be such a good trade-off.
554 static uint get_chunks_per_region();
555
556 G1Allocator* allocator() {
557 return _allocator;
558 }
559
560 G1YoungGCEvacFailureInjector* evac_failure_injector() { return &_evac_failure_injector; }
561
562 G1HeapVerifier* verifier() {
563 return _verifier;
564 }
565
566 G1MonitoringSupport* monitoring_support() {
567 assert(_monitoring_support != nullptr, "should have been initialized");
568 return _monitoring_support;
569 }
570
571 void resize_heap_if_necessary();
572
573 // Check if there is memory to uncommit and if so schedule a task to do it.
574 void uncommit_regions_if_necessary();
575 // Immediately uncommit uncommittable regions.
576 uint uncommit_regions(uint region_limit);
577 bool has_uncommittable_regions();
578
579 G1NUMA* numa() const { return _numa; }
580
581 // Expand the garbage-first heap by at least the given size (in bytes!).
582 // Returns true if the heap was expanded by the requested amount;
583 // false otherwise.
584 // (Rounds up to a HeapRegion boundary.)
585 bool expand(size_t expand_bytes, WorkerThreads* pretouch_workers = NULL, double* expand_time_ms = NULL);
586 bool expand_single_region(uint node_index);
587
588 // Returns the PLAB statistics for a given destination.
589 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest);
590
591 // Determines PLAB size for a given destination.
592 inline size_t desired_plab_sz(G1HeapRegionAttr dest);
593 // Clamp the given PLAB word size to allowed values. Prevents humongous PLAB sizes
594 // for two reasons:
595 // * PLABs are allocated using a similar paths as oops, but should
596 // never be in a humongous region
597 // * Allowing humongous PLABs needlessly churns the region free lists
598 inline size_t clamp_plab_size(size_t value) const;
599
600 // Do anything common to GC's.
601 void gc_prologue(bool full);
602 void gc_epilogue(bool full);
603
604 // Does the given region fulfill remembered set based eager reclaim candidate requirements?
605 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const;
606
607 inline bool is_humongous_reclaim_candidate(uint region);
608
609 // Remove from the reclaim candidate set. Also remove from the
610 // collection set so that later encounters avoid the slow path.
611 inline void set_humongous_is_live(oop obj);
612
613 // Register the given region to be part of the collection set.
614 inline void register_humongous_candidate_region_with_region_attr(uint index);
615
616 // We register a region with the fast "in collection set" test. We
617 // simply set to true the array slot corresponding to this region.
618 void register_young_region_with_region_attr(HeapRegion* r) {
619 _region_attr.set_in_young(r->hrm_index());
620 }
621 inline void register_new_survivor_region_with_region_attr(HeapRegion* r);
622 inline void register_region_with_region_attr(HeapRegion* r);
623 inline void register_old_region_with_region_attr(HeapRegion* r);
624 inline void register_optional_region_with_region_attr(HeapRegion* r);
625
626 void clear_region_attr(const HeapRegion* hr) {
627 _region_attr.clear(hr);
628 }
629
630 void clear_region_attr() {
631 _region_attr.clear();
632 }
633
634 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking
635 // for all regions.
636 void verify_region_attr_remset_is_tracked() PRODUCT_RETURN;
637
638 void clear_bitmap_for_region(HeapRegion* hr);
639
640 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause);
641
642 // This is called at the start of either a concurrent cycle or a Full
643 // GC to update the number of old marking cycles started.
644 void increment_old_marking_cycles_started();
645
646 // This is called at the end of either a concurrent cycle or a Full
647 // GC to update the number of old marking cycles completed. Those two
648 // can happen in a nested fashion, i.e., we start a concurrent
649 // cycle, a Full GC happens half-way through it which ends first,
650 // and then the cycle notices that a Full GC happened and ends
651 // too. The concurrent parameter is a boolean to help us do a bit
652 // tighter consistency checking in the method. If concurrent is
653 // false, the caller is the inner caller in the nesting (i.e., the
654 // Full GC). If concurrent is true, the caller is the outer caller
655 // in this nesting (i.e., the concurrent cycle). Further nesting is
656 // not currently supported. The end of this call also notifies
657 // the G1OldGCCount_lock in case a Java thread is waiting for a full
658 // GC to happen (e.g., it called System.gc() with
659 // +ExplicitGCInvokesConcurrent).
660 // whole_heap_examined should indicate that during that old marking
661 // cycle the whole heap has been examined for live objects (as opposed
662 // to only parts, or aborted before completion).
663 void increment_old_marking_cycles_completed(bool concurrent, bool whole_heap_examined);
664
665 uint old_marking_cycles_started() const {
666 return _old_marking_cycles_started;
667 }
668
669 uint old_marking_cycles_completed() const {
670 return _old_marking_cycles_completed;
671 }
672
673 G1HRPrinter* hr_printer() { return &_hr_printer; }
674
675 // Allocates a new heap region instance.
676 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr);
677
678 // Allocate the highest free region in the reserved heap. This will commit
679 // regions as necessary.
680 HeapRegion* alloc_highest_free_region();
681
682 // Frees a region by resetting its metadata and adding it to the free list
683 // passed as a parameter (this is usually a local list which will be appended
684 // to the master free list later or NULL if free list management is handled
685 // in another way).
686 // Callers must ensure they are the only one calling free on the given region
687 // at the same time.
688 void free_region(HeapRegion* hr, FreeRegionList* free_list);
689
690 // It dirties the cards that cover the block so that the post
691 // write barrier never queues anything when updating objects on this
692 // block. It is assumed (and in fact we assert) that the block
693 // belongs to a young region.
694 inline void dirty_young_block(HeapWord* start, size_t word_size);
695
696 // Frees a humongous region by collapsing it into individual regions
697 // and calling free_region() for each of them. The freed regions
698 // will be added to the free list that's passed as a parameter (this
699 // is usually a local list which will be appended to the master free
700 // list later).
701 // The method assumes that only a single thread is ever calling
702 // this for a particular region at once.
703 void free_humongous_region(HeapRegion* hr,
704 FreeRegionList* free_list);
705
706 // Facility for allocating a fixed range within the heap and marking
707 // the containing regions as 'archive'. For use at JVM init time, when the
708 // caller may mmap archived heap data at the specified range(s).
709 // Verify that the MemRegions specified in the argument array are within the
710 // reserved heap.
711 bool check_archive_addresses(MemRegion* range, size_t count);
712
713 // Commit the appropriate G1 regions containing the specified MemRegions
714 // and mark them as 'archive' regions. The regions in the array must be
715 // non-overlapping and in order of ascending address.
716 bool alloc_archive_regions(MemRegion* range, size_t count, bool open);
717
718 // Insert any required filler objects in the G1 regions around the specified
719 // ranges to make the regions parseable. This must be called after
720 // alloc_archive_regions, and after class loading has occurred.
721 void fill_archive_regions(MemRegion* range, size_t count);
722
723 // Populate the G1BlockOffsetTablePart for archived regions with the given
724 // memory ranges.
725 void populate_archive_regions_bot_part(MemRegion* range, size_t count);
726
727 // For each of the specified MemRegions, uncommit the containing G1 regions
728 // which had been allocated by alloc_archive_regions. This should be called
729 // rather than fill_archive_regions at JVM init time if the archive file
730 // mapping failed, with the same non-overlapping and sorted MemRegion array.
731 void dealloc_archive_regions(MemRegion* range, size_t count);
732
733 private:
734
735 // Shrink the garbage-first heap by at most the given size (in bytes!).
736 // (Rounds down to a HeapRegion boundary.)
737 void shrink(size_t shrink_bytes);
738 void shrink_helper(size_t expand_bytes);
739
740 // Schedule the VM operation that will do an evacuation pause to
741 // satisfy an allocation request of word_size. *succeeded will
742 // return whether the VM operation was successful (it did do an
743 // evacuation pause) or not (another thread beat us to it or the GC
744 // locker was active). Given that we should not be holding the
745 // Heap_lock when we enter this method, we will pass the
746 // gc_count_before (i.e., total_collections()) as a parameter since
747 // it has to be read while holding the Heap_lock. Currently, both
748 // methods that call do_collection_pause() release the Heap_lock
749 // before the call, so it's easy to read gc_count_before just before.
750 HeapWord* do_collection_pause(size_t word_size,
751 uint gc_count_before,
752 bool* succeeded,
753 GCCause::Cause gc_cause);
754
755 // Perform an incremental collection at a safepoint, possibly
756 // followed by a by-policy upgrade to a full collection. Returns
757 // false if unable to do the collection due to the GC locker being
758 // active, true otherwise.
759 // precondition: at safepoint on VM thread
760 // precondition: !is_gc_active()
761 bool do_collection_pause_at_safepoint();
762
763 // Helper for do_collection_pause_at_safepoint, containing the guts
764 // of the incremental collection pause, executed by the vm thread.
765 void do_collection_pause_at_safepoint_helper();
766
767 G1HeapVerifier::G1VerifyType young_collection_verify_type() const;
768 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type);
769 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type);
770
771 public:
772 // Start a concurrent cycle.
773 void start_concurrent_cycle(bool concurrent_operation_is_full_mark);
774
775 void prepare_for_mutator_after_young_collection();
776
777 void retire_tlabs();
778
779 void expand_heap_after_young_collection();
780 // Update object copying statistics.
781 void record_obj_copy_mem_stats();
782
783 private:
784 // The g1 remembered set of the heap.
785 G1RemSet* _rem_set;
786 // Global card set configuration
787 G1CardSetConfiguration _card_set_config;
788
789 G1MonotonicArenaFreePool _card_set_freelist_pool;
790
791 public:
792 // After a collection pause, reset eden and the collection set.
793 void clear_eden();
794 void clear_collection_set();
795
796 // Abandon the current collection set without recording policy
797 // statistics or updating free lists.
798 void abandon_collection_set(G1CollectionSet* collection_set);
799
800 // The concurrent marker (and the thread it runs in.)
801 G1ConcurrentMark* _cm;
802 G1ConcurrentMarkThread* _cm_thread;
803
804 // The concurrent refiner.
805 G1ConcurrentRefine* _cr;
806
807 // The parallel task queues
808 G1ScannerTasksQueueSet *_task_queues;
809
810 // ("Weak") Reference processing support.
811 //
812 // G1 has 2 instances of the reference processor class.
813 //
814 // One (_ref_processor_cm) handles reference object discovery and subsequent
815 // processing during concurrent marking cycles. Discovery is enabled/disabled
816 // at the start/end of a concurrent marking cycle.
817 //
818 // The other (_ref_processor_stw) handles reference object discovery and
819 // processing during incremental evacuation pauses and full GC pauses.
820 //
821 // ## Incremental evacuation pauses
822 //
823 // STW ref processor discovery is enabled/disabled at the start/end of an
824 // incremental evacuation pause. No particular handling of the CM ref
825 // processor is needed, apart from treating the discovered references as
826 // roots; CM discovery does not need to be temporarily disabled as all
827 // marking threads are paused during incremental evacuation pauses.
828 //
829 // ## Full GC pauses
830 //
831 // We abort any ongoing concurrent marking cycle, disable CM discovery, and
832 // temporarily substitute a new closure for the STW ref processor's
833 // _is_alive_non_header field (old value is restored after the full GC). Then
834 // STW ref processor discovery is enabled, and marking & compaction
835 // commences.
836
837 // The (stw) reference processor...
838 ReferenceProcessor* _ref_processor_stw;
839
840 // During reference object discovery, the _is_alive_non_header
841 // closure (if non-null) is applied to the referent object to
842 // determine whether the referent is live. If so then the
843 // reference object does not need to be 'discovered' and can
844 // be treated as a regular oop. This has the benefit of reducing
845 // the number of 'discovered' reference objects that need to
846 // be processed.
847 //
848 // Instance of the is_alive closure for embedding into the
849 // STW reference processor as the _is_alive_non_header field.
850 // Supplying a value for the _is_alive_non_header field is
851 // optional but doing so prevents unnecessary additions to
852 // the discovered lists during reference discovery.
853 G1STWIsAliveClosure _is_alive_closure_stw;
854
855 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw;
856
857 // The (concurrent marking) reference processor...
858 ReferenceProcessor* _ref_processor_cm;
859
860 // Instance of the concurrent mark is_alive closure for embedding
861 // into the Concurrent Marking reference processor as the
862 // _is_alive_non_header field. Supplying a value for the
863 // _is_alive_non_header field is optional but doing so prevents
864 // unnecessary additions to the discovered lists during reference
865 // discovery.
866 G1CMIsAliveClosure _is_alive_closure_cm;
867
868 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm;
869 public:
870
871 G1ScannerTasksQueueSet* task_queues() const;
872 G1ScannerTasksQueue* task_queue(uint i) const;
873
874 // Create a G1CollectedHeap.
875 // Must call the initialize method afterwards.
876 // May not return if something goes wrong.
877 G1CollectedHeap();
878
879 private:
880 jint initialize_concurrent_refinement();
881 jint initialize_service_thread();
882 public:
883 // Initialize the G1CollectedHeap to have the initial and
884 // maximum sizes and remembered and barrier sets
885 // specified by the policy object.
886 jint initialize() override;
887
888 // Returns whether concurrent mark threads (and the VM) are about to terminate.
889 bool concurrent_mark_is_terminating() const;
890
891 void stop() override;
892 void safepoint_synchronize_begin() override;
893 void safepoint_synchronize_end() override;
894
895 // Does operations required after initialization has been done.
896 void post_initialize() override;
897
898 // Initialize weak reference processing.
899 void ref_processing_init();
900
901 Name kind() const override {
902 return CollectedHeap::G1;
903 }
904
905 const char* name() const override {
906 return "G1";
907 }
908
909 const G1CollectorState* collector_state() const { return &_collector_state; }
910 G1CollectorState* collector_state() { return &_collector_state; }
911
912 // The current policy object for the collector.
913 G1Policy* policy() const { return _policy; }
914 // The remembered set.
915 G1RemSet* rem_set() const { return _rem_set; }
916
917 const G1MonotonicArenaFreePool* card_set_freelist_pool() const { return &_card_set_freelist_pool; }
918 G1MonotonicArenaFreePool* card_set_freelist_pool() { return &_card_set_freelist_pool; }
919
920 inline G1GCPhaseTimes* phase_times() const;
921
922 const G1CollectionSet* collection_set() const { return &_collection_set; }
923 G1CollectionSet* collection_set() { return &_collection_set; }
924
925 SoftRefPolicy* soft_ref_policy() override;
926
927 void initialize_serviceability() override;
928 MemoryUsage memory_usage() override;
929 GrowableArray<GCMemoryManager*> memory_managers() override;
930 GrowableArray<MemoryPool*> memory_pools() override;
931
932 void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) override;
933
934 static void start_codecache_marking_cycle_if_inactive(bool concurrent_mark_start);
935 static void finish_codecache_marking_cycle();
936
937 // The shared block offset table array.
938 G1BlockOffsetTable* bot() const { return _bot; }
939
940 // Reference Processing accessors
941
942 // The STW reference processor....
943 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
944
945 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; }
946 STWGCTimer* gc_timer_stw() const { return _gc_timer_stw; }
947
948 // The Concurrent Marking reference processor...
949 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
950
951 size_t unused_committed_regions_in_bytes() const;
952
953 size_t capacity() const override;
954 size_t used() const override;
955 // This should be called when we're not holding the heap lock. The
956 // result might be a bit inaccurate.
957 size_t used_unlocked() const;
958 size_t recalculate_used() const;
959
960 // These virtual functions do the actual allocation.
961 // Some heaps may offer a contiguous region for shared non-blocking
962 // allocation, via inlined code (by exporting the address of the top and
963 // end fields defining the extent of the contiguous allocation region.)
964 // But G1CollectedHeap doesn't yet support this.
965
966 bool is_maximal_no_gc() const override {
967 return _hrm.available() == 0;
968 }
969
970 // Returns true if an incremental GC should be upgrade to a full gc. This
971 // is done when there are no free regions and the heap can't be expanded.
972 bool should_upgrade_to_full_gc() const {
973 return is_maximal_no_gc() && num_free_regions() == 0;
974 }
975
976 // The current number of regions in the heap.
977 uint num_regions() const { return _hrm.length(); }
978
979 // The max number of regions reserved for the heap. Except for static array
980 // sizing purposes you probably want to use max_regions().
981 uint max_reserved_regions() const { return _hrm.reserved_length(); }
982
983 // Max number of regions that can be committed.
984 uint max_regions() const { return _hrm.max_length(); }
985
986 // The number of regions that are completely free.
987 uint num_free_regions() const { return _hrm.num_free_regions(); }
988
989 // The number of regions that can be allocated into.
990 uint num_free_or_available_regions() const { return num_free_regions() + _hrm.available(); }
991
992 MemoryUsage get_auxiliary_data_memory_usage() const {
993 return _hrm.get_auxiliary_data_memory_usage();
994 }
995
996 // The number of regions that are not completely free.
997 uint num_used_regions() const { return num_regions() - num_free_regions(); }
998
999 #ifdef ASSERT
1000 bool is_on_master_free_list(HeapRegion* hr) {
1001 return _hrm.is_free(hr);
1002 }
1003 #endif // ASSERT
1004
1005 inline void old_set_add(HeapRegion* hr);
1006 inline void old_set_remove(HeapRegion* hr);
1007
1008 inline void archive_set_add(HeapRegion* hr);
1009
1010 size_t non_young_capacity_bytes() {
1011 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes;
1012 }
1013
1014 // Determine whether the given region is one that we are using as an
1015 // old GC alloc region.
1016 bool is_old_gc_alloc_region(HeapRegion* hr);
1017
1018 // Perform a collection of the heap; intended for use in implementing
1019 // "System.gc". This probably implies as full a collection as the
1020 // "CollectedHeap" supports.
1021 void collect(GCCause::Cause cause) override;
1022
1023 // Perform a collection of the heap with the given cause.
1024 // Returns whether this collection actually executed.
1025 bool try_collect(GCCause::Cause cause, const G1GCCounters& counters_before);
1026
1027 void start_concurrent_gc_for_metadata_allocation(GCCause::Cause gc_cause);
1028
1029 void remove_from_old_gen_sets(const uint old_regions_removed,
1030 const uint archive_regions_removed,
1031 const uint humongous_regions_removed);
1032 void prepend_to_freelist(FreeRegionList* list);
1033 void decrement_summary_bytes(size_t bytes);
1034
1035 bool is_in(const void* p) const override;
1036
1037 // Return "TRUE" iff the given object address is within the collection
1038 // set. Assumes that the reference points into the heap.
1039 inline bool is_in_cset(const HeapRegion *hr) const;
1040 inline bool is_in_cset(oop obj) const;
1041 inline bool is_in_cset(HeapWord* addr) const;
1042
1043 inline bool is_in_cset_or_humongous_candidate(const oop obj);
1044
1045 private:
1046 // This array is used for a quick test on whether a reference points into
1047 // the collection set or not. Each of the array's elements denotes whether the
1048 // corresponding region is in the collection set or not.
1049 G1HeapRegionAttrBiasedMappedArray _region_attr;
1050
1051 public:
1052
1053 inline G1HeapRegionAttr region_attr(const void* obj) const;
1054 inline G1HeapRegionAttr region_attr(uint idx) const;
1055
1056 MemRegion reserved() const {
1057 return _hrm.reserved();
1058 }
1059
1060 bool is_in_reserved(const void* addr) const {
1061 return reserved().contains(addr);
1062 }
1063
1064 G1CardTable* card_table() const {
1065 return _card_table;
1066 }
1067
1068 // Iteration functions.
1069
1070 void object_iterate_parallel(ObjectClosure* cl, uint worker_id, HeapRegionClaimer* claimer);
1071
1072 // Iterate over all objects, calling "cl.do_object" on each.
1073 void object_iterate(ObjectClosure* cl) override;
1074
1075 ParallelObjectIteratorImpl* parallel_object_iterator(uint thread_num) override;
1076
1077 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1078 void keep_alive(oop obj) override;
1079
1080 // Iterate over heap regions, in address order, terminating the
1081 // iteration early if the "do_heap_region" method returns "true".
1082 void heap_region_iterate(HeapRegionClosure* blk) const;
1083 void heap_region_iterate(HeapRegionIndexClosure* blk) const;
1084
1085 // Return the region with the given index. It assumes the index is valid.
1086 inline HeapRegion* region_at(uint index) const;
1087 inline HeapRegion* region_at_or_null(uint index) const;
1088
1089 // Return the next region (by index) that is part of the same
1090 // humongous object that hr is part of.
1091 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
1092
1093 // Calculate the region index of the given address. Given address must be
1094 // within the heap.
1095 inline uint addr_to_region(const void* addr) const;
1096
1097 inline HeapWord* bottom_addr_for_region(uint index) const;
1098
1099 // Two functions to iterate over the heap regions in parallel. Threads
1100 // compete using the HeapRegionClaimer to claim the regions before
1101 // applying the closure on them.
1102 // The _from_worker_offset version uses the HeapRegionClaimer and
1103 // the worker id to calculate a start offset to prevent all workers to
1104 // start from the point.
1105 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl,
1106 HeapRegionClaimer* hrclaimer,
1107 uint worker_id) const;
1108
1109 void heap_region_par_iterate_from_start(HeapRegionClosure* cl,
1110 HeapRegionClaimer* hrclaimer) const;
1111
1112 // Iterate over all regions in the collection set in parallel.
1113 void collection_set_par_iterate_all(HeapRegionClosure* cl,
1114 HeapRegionClaimer* hr_claimer,
1115 uint worker_id);
1116
1117 // Iterate over all regions currently in the current collection set.
1118 void collection_set_iterate_all(HeapRegionClosure* blk);
1119
1120 // Iterate over the regions in the current increment of the collection set.
1121 // Starts the iteration so that the start regions of a given worker id over the
1122 // set active_workers are evenly spread across the set of collection set regions
1123 // to be iterated.
1124 // The variant with the HeapRegionClaimer guarantees that the closure will be
1125 // applied to a particular region exactly once.
1126 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) {
1127 collection_set_iterate_increment_from(blk, NULL, worker_id);
1128 }
1129 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id);
1130 // Iterate over the array of region indexes, uint regions[length], applying
1131 // the given HeapRegionClosure on each region. The worker_id will determine where
1132 // to start the iteration to allow for more efficient parallel iteration.
1133 void par_iterate_regions_array(HeapRegionClosure* cl,
1134 HeapRegionClaimer* hr_claimer,
1135 const uint regions[],
1136 size_t length,
1137 uint worker_id) const;
1138
1139 // Returns the HeapRegion that contains addr. addr must not be nullptr.
1140 inline HeapRegion* heap_region_containing(const void* addr) const;
1141
1142 // Returns the HeapRegion that contains addr, or nullptr if that is an uncommitted
1143 // region. addr must not be nullptr.
1144 inline HeapRegion* heap_region_containing_or_null(const void* addr) const;
1145
1146 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1147 // each address in the (reserved) heap is a member of exactly
1148 // one block. The defining characteristic of a block is that it is
1149 // possible to find its size, and thus to progress forward to the next
1150 // block. (Blocks may be of different sizes.) Thus, blocks may
1151 // represent Java objects, or they might be free blocks in a
1152 // free-list-based heap (or subheap), as long as the two kinds are
1153 // distinguishable and the size of each is determinable.
1154
1155 // Returns the address of the start of the "block" that contains the
1156 // address "addr". We say "blocks" instead of "object" since some heaps
1157 // may not pack objects densely; a chunk may either be an object or a
1158 // non-object.
1159 HeapWord* block_start(const void* addr) const;
1160
1161 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1162 // the block is an object.
1163 bool block_is_obj(const HeapWord* addr) const;
1164
1165 // Section on thread-local allocation buffers (TLABs)
1166 // See CollectedHeap for semantics.
1167
1168 size_t tlab_capacity(Thread* ignored) const override;
1169 size_t tlab_used(Thread* ignored) const override;
1170 size_t max_tlab_size() const override;
1171 size_t unsafe_max_tlab_alloc(Thread* ignored) const override;
1172
1173 inline bool is_in_young(const oop obj) const;
1174 inline bool requires_barriers(stackChunkOop obj) const override;
1175
1176 // Returns "true" iff the given word_size is "very large".
1177 static bool is_humongous(size_t word_size) {
1178 // Note this has to be strictly greater-than as the TLABs
1179 // are capped at the humongous threshold and we want to
1180 // ensure that we don't try to allocate a TLAB as
1181 // humongous and that we don't allocate a humongous
1182 // object in a TLAB.
1183 return word_size > _humongous_object_threshold_in_words;
1184 }
1185
1186 // Returns the humongous threshold for a specific region size
1187 static size_t humongous_threshold_for(size_t region_size) {
1188 return (region_size / 2);
1189 }
1190
1191 // Returns the number of regions the humongous object of the given word size
1192 // requires.
1193 static size_t humongous_obj_size_in_regions(size_t word_size);
1194
1195 // Print the maximum heap capacity.
1196 size_t max_capacity() const override;
1197
1198 Tickspan time_since_last_collection() const { return Ticks::now() - _collection_pause_end; }
1199
1200 // Convenience function to be used in situations where the heap type can be
1201 // asserted to be this type.
1202 static G1CollectedHeap* heap() {
1203 return named_heap<G1CollectedHeap>(CollectedHeap::G1);
1204 }
1205
1206 void set_region_short_lived_locked(HeapRegion* hr);
1207 // add appropriate methods for any other surv rate groups
1208
1209 G1SurvivorRegions* survivor() { return &_survivor; }
1210
1211 uint eden_regions_count() const { return _eden.length(); }
1212 uint eden_regions_count(uint node_index) const { return _eden.regions_on_node(node_index); }
1213 uint survivor_regions_count() const { return _survivor.length(); }
1214 uint survivor_regions_count(uint node_index) const { return _survivor.regions_on_node(node_index); }
1215 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); }
1216 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); }
1217 uint young_regions_count() const { return _eden.length() + _survivor.length(); }
1218 uint old_regions_count() const { return _old_set.length(); }
1219 uint archive_regions_count() const { return _archive_set.length(); }
1220 uint humongous_regions_count() const { return _humongous_set.length(); }
1221
1222 #ifdef ASSERT
1223 bool check_young_list_empty();
1224 #endif
1225
1226 bool is_marked(oop obj) const;
1227
1228 inline static bool is_obj_filler(const oop obj);
1229 // Determine if an object is dead, given the object and also
1230 // the region to which the object belongs.
1231 inline bool is_obj_dead(const oop obj, const HeapRegion* hr) const;
1232
1233 // Determine if an object is dead, given only the object itself.
1234 // This will find the region to which the object belongs and
1235 // then call the region version of the same function.
1236 // If obj is NULL it is not dead.
1237 inline bool is_obj_dead(const oop obj) const;
1238
1239 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const;
1240 inline bool is_obj_dead_full(const oop obj) const;
1241
1242 // Mark the live object that failed evacuation in the bitmap.
1243 void mark_evac_failure_object(uint worker_id, oop obj, size_t obj_size) const;
1244
1245 G1ConcurrentMark* concurrent_mark() const { return _cm; }
1246
1247 // Refinement
1248
1249 G1ConcurrentRefine* concurrent_refine() const { return _cr; }
1250
1251 // Optimized nmethod scanning support routines
1252
1253 // Register the given nmethod with the G1 heap.
1254 void register_nmethod(nmethod* nm) override;
1255
1256 // Unregister the given nmethod from the G1 heap.
1257 void unregister_nmethod(nmethod* nm) override;
1258
1259 // No nmethod verification implemented.
1260 void verify_nmethod(nmethod* nm) override {}
1261
1262 // Recalculate amount of used memory after GC. Must be called after all allocation
1263 // has finished.
1264 void update_used_after_gc(bool evacuation_failed);
1265
1266 // Rebuild the code root lists for each region
1267 // after a full GC.
1268 void rebuild_code_roots();
1269
1270 // Performs cleaning of data structures after class unloading.
1271 void complete_cleaning(bool class_unloading_occurred);
1272
1273 // Verification
1274
1275 // Perform any cleanup actions necessary before allowing a verification.
1276 void prepare_for_verify() override;
1277
1278 // Perform verification.
1279 void verify(VerifyOption vo) override;
1280
1281 // WhiteBox testing support.
1282 bool supports_concurrent_gc_breakpoints() const override;
1283
1284 WorkerThreads* safepoint_workers() override { return _workers; }
1285
1286 bool is_archived_object(oop object) const override;
1287
1288 // The methods below are here for convenience and dispatch the
1289 // appropriate method depending on value of the given VerifyOption
1290 // parameter. The values for that parameter, and their meanings,
1291 // are the same as those above.
1292
1293 bool is_obj_dead_cond(const oop obj,
1294 const HeapRegion* hr,
1295 const VerifyOption vo) const;
1296
1297 bool is_obj_dead_cond(const oop obj,
1298 const VerifyOption vo) const;
1299
1300 G1HeapSummary create_g1_heap_summary();
1301 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats);
1302
1303 void pin_object(JavaThread* thread, oop obj) override;
1304 void unpin_object(JavaThread* thread, oop obj) override;
1305
1306 // Printing
1307 private:
1308 void print_heap_regions() const;
1309 void print_regions_on(outputStream* st) const;
1310
1311 public:
1312 void print_on(outputStream* st) const override;
1313 void print_extended_on(outputStream* st) const override;
1314 void print_on_error(outputStream* st) const override;
1315
1316 void gc_threads_do(ThreadClosure* tc) const override;
1317
1318 // Override
1319 void print_tracing_info() const override;
1320
1321 // Used to print information about locations in the hs_err file.
1322 bool print_location(outputStream* st, void* addr) const override;
1323 };
1324
1325 // Scoped object that performs common pre- and post-gc heap printing operations.
1326 class G1HeapPrinterMark : public StackObj {
1327 G1CollectedHeap* _g1h;
1328 G1HeapTransition _heap_transition;
1329
1330 public:
1331 G1HeapPrinterMark(G1CollectedHeap* g1h);
1332 ~G1HeapPrinterMark();
1333 };
1334
1335 // Scoped object that performs common pre- and post-gc operations related to
1336 // JFR events.
1337 class G1JFRTracerMark : public StackObj {
1338 protected:
1339 STWGCTimer* _timer;
1340 GCTracer* _tracer;
1341
1342 public:
1343 G1JFRTracerMark(STWGCTimer* timer, GCTracer* tracer);
1344 ~G1JFRTracerMark();
1345 };
1346
1347 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP