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 SlidingForwarding;
88 class WorkerThreads;
89
90 typedef OverflowTaskQueue<ScannerTask, mtGC> G1ScannerTasksQueue;
91 typedef GenericTaskQueueSet<G1ScannerTasksQueue, mtGC> G1ScannerTasksQueueSet;
92
93 typedef int RegionIdx_t; // needs to hold [ 0..max_reserved_regions() )
94 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
95
96 // The G1 STW is alive closure.
97 // An instance is embedded into the G1CH and used as the
98 // (optional) _is_alive_non_header closure in the STW
99 // reference processor. It is also extensively used during
100 // reference processing during STW evacuation pauses.
101 class G1STWIsAliveClosure : public BoolObjectClosure {
102 G1CollectedHeap* _g1h;
103 public:
104 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
105 bool do_object_b(oop p) override;
106 };
107
108 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure {
109 G1CollectedHeap* _g1h;
110 public:
111 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
112 bool do_object_b(oop p) override;
113 };
114
115 class G1RegionMappingChangedListener : public G1MappingChangedListener {
116 private:
117 void reset_from_card_cache(uint start_idx, size_t num_regions);
118 public:
119 void on_commit(uint start_idx, size_t num_regions, bool zero_filled) override;
120 };
121
122 class G1CollectedHeap : public CollectedHeap {
123 friend class VM_G1CollectForAllocation;
124 friend class VM_G1CollectFull;
125 friend class VM_G1TryInitiateConcMark;
126 friend class VMStructs;
127 friend class MutatorAllocRegion;
128 friend class G1FullCollector;
129 friend class G1GCAllocRegion;
130 friend class G1HeapVerifier;
131
132 friend class G1YoungGCVerifierMark;
133
134 // Closures used in implementation.
135 friend class G1EvacuateRegionsTask;
136 friend class G1PLABAllocator;
137
138 // Other related classes.
139 friend class G1HeapPrinterMark;
140 friend class HeapRegionClaimer;
141
142 // Testing classes.
143 friend class G1CheckRegionAttrTableClosure;
144
145 private:
146 G1ServiceThread* _service_thread;
147 G1ServiceTask* _periodic_gc_task;
148 G1SegmentedArrayFreeMemoryTask* _free_segmented_array_memory_task;
149
150 WorkerThreads* _workers;
151 G1CardTable* _card_table;
152
153 Ticks _collection_pause_end;
154
155 SoftRefPolicy _soft_ref_policy;
156
157 static size_t _humongous_object_threshold_in_words;
158
159 // These sets keep track of old, archive and humongous regions respectively.
160 HeapRegionSet _old_set;
161 HeapRegionSet _archive_set;
162 HeapRegionSet _humongous_set;
163
164 // Young gen memory statistics before GC.
165 G1SegmentedArrayMemoryStats _young_gen_card_set_stats;
166 // Collection set candidates memory statistics after GC.
167 G1SegmentedArrayMemoryStats _collection_set_candidates_card_set_stats;
168
169 // The block offset table for the G1 heap.
170 G1BlockOffsetTable* _bot;
171
172 public:
173 void rebuild_free_region_list();
174 // Start a new incremental collection set for the next pause.
175 void start_new_collection_set();
176
177 void prepare_region_for_full_compaction(HeapRegion* hr);
178
179 private:
180 // Rebuilds the region sets / lists so that they are repopulated to
181 // reflect the contents of the heap. The only exception is the
182 // humongous set which was not torn down in the first place. If
183 // free_list_only is true, it will only rebuild the free list.
184 void rebuild_region_sets(bool free_list_only);
185
186 // Callback for region mapping changed events.
187 G1RegionMappingChangedListener _listener;
188
189 // Handle G1 NUMA support.
190 G1NUMA* _numa;
191
192 // The sequence of all heap regions in the heap.
193 HeapRegionManager _hrm;
194
195 // Manages all allocations with regions except humongous object allocations.
196 G1Allocator* _allocator;
197
198 G1YoungGCEvacFailureInjector _evac_failure_injector;
199
200 // Manages all heap verification.
201 G1HeapVerifier* _verifier;
202
203 // Outside of GC pauses, the number of bytes used in all regions other
204 // than the current allocation region(s).
205 volatile size_t _summary_bytes_used;
206
207 void increase_used(size_t bytes);
208 void decrease_used(size_t bytes);
209
210 void set_used(size_t bytes);
211
212 // Number of bytes used in all regions during GC. Typically changed when
213 // retiring a GC alloc region.
214 size_t _bytes_used_during_gc;
215
216 public:
217 size_t bytes_used_during_gc() const { return _bytes_used_during_gc; }
218
219 private:
220 // Class that handles archive allocation ranges.
221 G1ArchiveAllocator* _archive_allocator;
222
223 // GC allocation statistics policy for survivors.
224 G1EvacStats _survivor_evac_stats;
225
226 // GC allocation statistics policy for tenured objects.
227 G1EvacStats _old_evac_stats;
228
229 // Helper for monitoring and management support.
230 G1MonitoringSupport* _monitoring_support;
231
232 SlidingForwarding* _forwarding;
233
234 // Records whether the region at the given index is (still) a
235 // candidate for eager reclaim. Only valid for humongous start
236 // regions; other regions have unspecified values. Humongous start
237 // regions are initialized at start of collection pause, with
238 // candidates removed from the set as they are found reachable from
239 // roots or the young generation.
240 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> {
241 protected:
242 bool default_value() const override { return false; }
243 public:
244 void clear() { G1BiasedMappedArray<bool>::clear(); }
245 void set_candidate(uint region, bool value) {
246 set_by_index(region, value);
247 }
248 bool is_candidate(uint region) {
249 return get_by_index(region);
250 }
251 };
252
253 HumongousReclaimCandidates _humongous_reclaim_candidates;
254 uint _num_humongous_objects; // Current amount of (all) humongous objects found in the heap.
255 uint _num_humongous_reclaim_candidates; // Number of humongous object eager reclaim candidates.
256 public:
257 uint num_humongous_objects() const { return _num_humongous_objects; }
258 uint num_humongous_reclaim_candidates() const { return _num_humongous_reclaim_candidates; }
259 bool has_humongous_reclaim_candidates() const { return _num_humongous_reclaim_candidates > 0; }
260
261 bool should_do_eager_reclaim() const;
262
263 void set_humongous_stats(uint num_humongous_total, uint num_humongous_candidates);
264
265 bool should_sample_collection_set_candidates() const;
266 void set_collection_set_candidates_stats(G1SegmentedArrayMemoryStats& stats);
267 void set_young_gen_card_set_stats(const G1SegmentedArrayMemoryStats& stats);
268
269 SlidingForwarding* forwarding() const {
270 return _forwarding;
271 }
272
273 private:
274
275 G1HRPrinter _hr_printer;
276
277 // Return true if an explicit GC should start a concurrent cycle instead
278 // of doing a STW full GC. A concurrent cycle should be started if:
279 // (a) cause == _g1_humongous_allocation,
280 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent,
281 // (c) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent,
282 // (d) cause == _wb_conc_mark or _wb_breakpoint,
283 // (e) cause == _g1_periodic_collection and +G1PeriodicGCInvokesConcurrent.
284 bool should_do_concurrent_full_gc(GCCause::Cause cause);
285
286 // Attempt to start a concurrent cycle with the indicated cause.
287 // precondition: should_do_concurrent_full_gc(cause)
288 bool try_collect_concurrently(GCCause::Cause cause,
289 uint gc_counter,
290 uint old_marking_started_before);
291
292 // indicates whether we are in young or mixed GC mode
293 G1CollectorState _collector_state;
294
295 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
296 // concurrent cycles) we have started.
297 volatile uint _old_marking_cycles_started;
298
299 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
300 // concurrent cycles) we have completed.
301 volatile uint _old_marking_cycles_completed;
302
303 // This is a non-product method that is helpful for testing. It is
304 // called at the end of a GC and artificially expands the heap by
305 // allocating a number of dead regions. This way we can induce very
306 // frequent marking cycles and stress the cleanup / concurrent
307 // cleanup code more (as all the regions that will be allocated by
308 // this method will be found dead by the marking cycle).
309 void allocate_dummy_regions() PRODUCT_RETURN;
310
311 // Create a memory mapper for auxiliary data structures of the given size and
312 // translation factor.
313 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description,
314 size_t size,
315 size_t translation_factor);
316
317 void trace_heap(GCWhen::Type when, const GCTracer* tracer) override;
318
319 // These are macros so that, if the assert fires, we get the correct
320 // line number, file, etc.
321
322 #define heap_locking_asserts_params(_extra_message_) \
323 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
324 (_extra_message_), \
325 BOOL_TO_STR(Heap_lock->owned_by_self()), \
326 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
327 BOOL_TO_STR(Thread::current()->is_VM_thread())
328
329 #define assert_heap_locked() \
330 do { \
331 assert(Heap_lock->owned_by_self(), \
332 heap_locking_asserts_params("should be holding the Heap_lock")); \
333 } while (0)
334
335 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
336 do { \
337 assert(Heap_lock->owned_by_self() || \
338 (SafepointSynchronize::is_at_safepoint() && \
339 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
340 heap_locking_asserts_params("should be holding the Heap_lock or " \
341 "should be at a safepoint")); \
342 } while (0)
343
344 #define assert_heap_locked_and_not_at_safepoint() \
345 do { \
346 assert(Heap_lock->owned_by_self() && \
347 !SafepointSynchronize::is_at_safepoint(), \
348 heap_locking_asserts_params("should be holding the Heap_lock and " \
349 "should not be at a safepoint")); \
350 } while (0)
351
352 #define assert_heap_not_locked() \
353 do { \
354 assert(!Heap_lock->owned_by_self(), \
355 heap_locking_asserts_params("should not be holding the Heap_lock")); \
356 } while (0)
357
358 #define assert_heap_not_locked_and_not_at_safepoint() \
359 do { \
360 assert(!Heap_lock->owned_by_self() && \
361 !SafepointSynchronize::is_at_safepoint(), \
362 heap_locking_asserts_params("should not be holding the Heap_lock and " \
363 "should not be at a safepoint")); \
364 } while (0)
365
366 #define assert_at_safepoint_on_vm_thread() \
367 do { \
368 assert_at_safepoint(); \
369 assert(Thread::current_or_null() != NULL, "no current thread"); \
370 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \
371 } while (0)
372
373 #ifdef ASSERT
374 #define assert_used_and_recalculate_used_equal(g1h) \
375 do { \
376 size_t cur_used_bytes = g1h->used(); \
377 size_t recal_used_bytes = g1h->recalculate_used(); \
378 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \
379 " same as recalculated used(" SIZE_FORMAT ").", \
380 cur_used_bytes, recal_used_bytes); \
381 } while (0)
382 #else
383 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0)
384 #endif
385
386 // The young region list.
387 G1EdenRegions _eden;
388 G1SurvivorRegions _survivor;
389
390 STWGCTimer* _gc_timer_stw;
391
392 G1NewTracer* _gc_tracer_stw;
393
394 // The current policy object for the collector.
395 G1Policy* _policy;
396 G1HeapSizingPolicy* _heap_sizing_policy;
397
398 G1CollectionSet _collection_set;
399
400 // Try to allocate a single non-humongous HeapRegion sufficient for
401 // an allocation of the given word_size. If do_expand is true,
402 // attempt to expand the heap if necessary to satisfy the allocation
403 // request. 'type' takes the type of region to be allocated. (Use constants
404 // Old, Eden, Humongous, Survivor defined in HeapRegionType.)
405 HeapRegion* new_region(size_t word_size,
406 HeapRegionType type,
407 bool do_expand,
408 uint node_index = G1NUMA::AnyNodeIndex);
409
410 // Initialize a contiguous set of free regions of length num_regions
411 // and starting at index first so that they appear as a single
412 // humongous region.
413 HeapWord* humongous_obj_allocate_initialize_regions(HeapRegion* first_hr,
414 uint num_regions,
415 size_t word_size);
416
417 // Attempt to allocate a humongous object of the given size. Return
418 // NULL if unsuccessful.
419 HeapWord* humongous_obj_allocate(size_t word_size);
420
421 // The following two methods, allocate_new_tlab() and
422 // mem_allocate(), are the two main entry points from the runtime
423 // into the G1's allocation routines. They have the following
424 // assumptions:
425 //
426 // * They should both be called outside safepoints.
427 //
428 // * They should both be called without holding the Heap_lock.
429 //
430 // * All allocation requests for new TLABs should go to
431 // allocate_new_tlab().
432 //
433 // * All non-TLAB allocation requests should go to mem_allocate().
434 //
435 // * If either call cannot satisfy the allocation request using the
436 // current allocating region, they will try to get a new one. If
437 // this fails, they will attempt to do an evacuation pause and
438 // retry the allocation.
439 //
440 // * If all allocation attempts fail, even after trying to schedule
441 // an evacuation pause, allocate_new_tlab() will return NULL,
442 // whereas mem_allocate() will attempt a heap expansion and/or
443 // schedule a Full GC.
444 //
445 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
446 // should never be called with word_size being humongous. All
447 // humongous allocation requests should go to mem_allocate() which
448 // will satisfy them with a special path.
449
450 HeapWord* allocate_new_tlab(size_t min_size,
451 size_t requested_size,
452 size_t* actual_size) override;
453
454 HeapWord* mem_allocate(size_t word_size,
455 bool* gc_overhead_limit_was_exceeded) override;
456
457 // First-level mutator allocation attempt: try to allocate out of
458 // the mutator alloc region without taking the Heap_lock. This
459 // should only be used for non-humongous allocations.
460 inline HeapWord* attempt_allocation(size_t min_word_size,
461 size_t desired_word_size,
462 size_t* actual_word_size);
463
464 // Second-level mutator allocation attempt: take the Heap_lock and
465 // retry the allocation attempt, potentially scheduling a GC
466 // pause. This should only be used for non-humongous allocations.
467 HeapWord* attempt_allocation_slow(size_t word_size);
468
469 // Takes the Heap_lock and attempts a humongous allocation. It can
470 // potentially schedule a GC pause.
471 HeapWord* attempt_allocation_humongous(size_t word_size);
472
473 // Allocation attempt that should be called during safepoints (e.g.,
474 // at the end of a successful GC). expect_null_mutator_alloc_region
475 // specifies whether the mutator alloc region is expected to be NULL
476 // or not.
477 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
478 bool expect_null_mutator_alloc_region);
479
480 // These methods are the "callbacks" from the G1AllocRegion class.
481
482 // For mutator alloc regions.
483 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index);
484 void retire_mutator_alloc_region(HeapRegion* alloc_region,
485 size_t allocated_bytes);
486
487 // For GC alloc regions.
488 bool has_more_regions(G1HeapRegionAttr dest);
489 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest, uint node_index);
490 void retire_gc_alloc_region(HeapRegion* alloc_region,
491 size_t allocated_bytes, G1HeapRegionAttr dest);
492
493 // - if explicit_gc is true, the GC is for a System.gc() etc,
494 // otherwise it's for a failed allocation.
495 // - if clear_all_soft_refs is true, all soft references should be
496 // cleared during the GC.
497 // - if do_maximal_compaction is true, full gc will do a maximally
498 // compacting collection, leaving no dead wood.
499 // - it returns false if it is unable to do the collection due to the
500 // GC locker being active, true otherwise.
501 bool do_full_collection(bool explicit_gc,
502 bool clear_all_soft_refs,
503 bool do_maximal_compaction);
504
505 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
506 void do_full_collection(bool clear_all_soft_refs) override;
507
508 // Helper to do a full collection that clears soft references.
509 bool upgrade_to_full_collection();
510
511 // Callback from VM_G1CollectForAllocation operation.
512 // This function does everything necessary/possible to satisfy a
513 // failed allocation request (including collection, expansion, etc.)
514 HeapWord* satisfy_failed_allocation(size_t word_size,
515 bool* succeeded);
516 // Internal helpers used during full GC to split it up to
517 // increase readability.
518 void abort_concurrent_cycle();
519 void verify_before_full_collection(bool explicit_gc);
520 void prepare_heap_for_full_collection();
521 void prepare_heap_for_mutators();
522 void abort_refinement();
523 void verify_after_full_collection();
524 void print_heap_after_full_collection();
525
526 // Helper method for satisfy_failed_allocation()
527 HeapWord* satisfy_failed_allocation_helper(size_t word_size,
528 bool do_gc,
529 bool maximal_compaction,
530 bool expect_null_mutator_alloc_region,
531 bool* gc_succeeded);
532
533 // Attempting to expand the heap sufficiently
534 // to support an allocation of the given "word_size". If
535 // successful, perform the allocation and return the address of the
536 // allocated block, or else "NULL".
537 HeapWord* expand_and_allocate(size_t word_size);
538
539 void verify_numa_regions(const char* desc);
540
541 public:
542 // If during a concurrent start pause we may install a pending list head which is not
543 // otherwise reachable, ensure that it is marked in the bitmap for concurrent marking
544 // to discover.
545 void make_pending_list_reachable();
546
547 G1ServiceThread* service_thread() const { return _service_thread; }
548
549 WorkerThreads* workers() const { return _workers; }
550
551 // Run the given batch task using the workers.
552 void run_batch_task(G1BatchedTask* cl);
553
554 G1Allocator* allocator() {
555 return _allocator;
556 }
557
558 G1YoungGCEvacFailureInjector* evac_failure_injector() { return &_evac_failure_injector; }
559
560 G1HeapVerifier* verifier() {
561 return _verifier;
562 }
563
564 G1MonitoringSupport* monitoring_support() {
565 assert(_monitoring_support != nullptr, "should have been initialized");
566 return _monitoring_support;
567 }
568
569 void resize_heap_if_necessary();
570
571 // Check if there is memory to uncommit and if so schedule a task to do it.
572 void uncommit_regions_if_necessary();
573 // Immediately uncommit uncommittable regions.
574 uint uncommit_regions(uint region_limit);
575 bool has_uncommittable_regions();
576
577 G1NUMA* numa() const { return _numa; }
578
579 // Expand the garbage-first heap by at least the given size (in bytes!).
580 // Returns true if the heap was expanded by the requested amount;
581 // false otherwise.
582 // (Rounds up to a HeapRegion boundary.)
583 bool expand(size_t expand_bytes, WorkerThreads* pretouch_workers = NULL, double* expand_time_ms = NULL);
584 bool expand_single_region(uint node_index);
585
586 // Returns the PLAB statistics for a given destination.
587 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest);
588
589 // Determines PLAB size for a given destination.
590 inline size_t desired_plab_sz(G1HeapRegionAttr dest);
591
592 // Do anything common to GC's.
593 void gc_prologue(bool full);
594 void gc_epilogue(bool full);
595
596 // Does the given region fulfill remembered set based eager reclaim candidate requirements?
597 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const;
598
599 // Modify the reclaim candidate set and test for presence.
600 // These are only valid for starts_humongous regions.
601 inline void set_humongous_reclaim_candidate(uint region, bool value);
602 inline bool is_humongous_reclaim_candidate(uint region);
603
604 // Remove from the reclaim candidate set. Also remove from the
605 // collection set so that later encounters avoid the slow path.
606 inline void set_humongous_is_live(oop obj);
607
608 // Register the given region to be part of the collection set.
609 inline void register_humongous_region_with_region_attr(uint index);
610
611 // We register a region with the fast "in collection set" test. We
612 // simply set to true the array slot corresponding to this region.
613 void register_young_region_with_region_attr(HeapRegion* r) {
614 _region_attr.set_in_young(r->hrm_index());
615 }
616 inline void register_new_survivor_region_with_region_attr(HeapRegion* r);
617 inline void register_region_with_region_attr(HeapRegion* r);
618 inline void register_old_region_with_region_attr(HeapRegion* r);
619 inline void register_optional_region_with_region_attr(HeapRegion* r);
620
621 void clear_region_attr(const HeapRegion* hr) {
622 _region_attr.clear(hr);
623 }
624
625 void clear_region_attr() {
626 _region_attr.clear();
627 }
628
629 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking
630 // for all regions.
631 void verify_region_attr_remset_is_tracked() PRODUCT_RETURN;
632
633 void clear_prev_bitmap_for_region(HeapRegion* hr);
634
635 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause);
636
637 // This is called at the start of either a concurrent cycle or a Full
638 // GC to update the number of old marking cycles started.
639 void increment_old_marking_cycles_started();
640
641 // This is called at the end of either a concurrent cycle or a Full
642 // GC to update the number of old marking cycles completed. Those two
643 // can happen in a nested fashion, i.e., we start a concurrent
644 // cycle, a Full GC happens half-way through it which ends first,
645 // and then the cycle notices that a Full GC happened and ends
646 // too. The concurrent parameter is a boolean to help us do a bit
647 // tighter consistency checking in the method. If concurrent is
648 // false, the caller is the inner caller in the nesting (i.e., the
649 // Full GC). If concurrent is true, the caller is the outer caller
650 // in this nesting (i.e., the concurrent cycle). Further nesting is
651 // not currently supported. The end of this call also notifies
652 // the G1OldGCCount_lock in case a Java thread is waiting for a full
653 // GC to happen (e.g., it called System.gc() with
654 // +ExplicitGCInvokesConcurrent).
655 // whole_heap_examined should indicate that during that old marking
656 // cycle the whole heap has been examined for live objects (as opposed
657 // to only parts, or aborted before completion).
658 void increment_old_marking_cycles_completed(bool concurrent, bool whole_heap_examined);
659
660 uint old_marking_cycles_started() const {
661 return _old_marking_cycles_started;
662 }
663
664 uint old_marking_cycles_completed() const {
665 return _old_marking_cycles_completed;
666 }
667
668 G1HRPrinter* hr_printer() { return &_hr_printer; }
669
670 // Allocates a new heap region instance.
671 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr);
672
673 // Allocate the highest free region in the reserved heap. This will commit
674 // regions as necessary.
675 HeapRegion* alloc_highest_free_region();
676
677 // Frees a region by resetting its metadata and adding it to the free list
678 // passed as a parameter (this is usually a local list which will be appended
679 // to the master free list later or NULL if free list management is handled
680 // in another way).
681 // Callers must ensure they are the only one calling free on the given region
682 // at the same time.
683 void free_region(HeapRegion* hr, FreeRegionList* free_list);
684
685 // It dirties the cards that cover the block so that the post
686 // write barrier never queues anything when updating objects on this
687 // block. It is assumed (and in fact we assert) that the block
688 // belongs to a young region.
689 inline void dirty_young_block(HeapWord* start, size_t word_size);
690
691 // Frees a humongous region by collapsing it into individual regions
692 // and calling free_region() for each of them. The freed regions
693 // will be added to the free list that's passed as a parameter (this
694 // is usually a local list which will be appended to the master free
695 // list later).
696 // The method assumes that only a single thread is ever calling
697 // this for a particular region at once.
698 void free_humongous_region(HeapRegion* hr,
699 FreeRegionList* free_list);
700
701 // Facility for allocating in 'archive' regions in high heap memory and
702 // recording the allocated ranges. These should all be called from the
703 // VM thread at safepoints, without the heap lock held. They can be used
704 // to create and archive a set of heap regions which can be mapped at the
705 // same fixed addresses in a subsequent JVM invocation.
706 void begin_archive_alloc_range(bool open = false);
707
708 // Check if the requested size would be too large for an archive allocation.
709 bool is_archive_alloc_too_large(size_t word_size);
710
711 // Allocate memory of the requested size from the archive region. This will
712 // return NULL if the size is too large or if no memory is available. It
713 // does not trigger a garbage collection.
714 HeapWord* archive_mem_allocate(size_t word_size);
715
716 // Optionally aligns the end address and returns the allocated ranges in
717 // an array of MemRegions in order of ascending addresses.
718 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges,
719 size_t end_alignment_in_bytes = 0);
720
721 // Facility for allocating a fixed range within the heap and marking
722 // the containing regions as 'archive'. For use at JVM init time, when the
723 // caller may mmap archived heap data at the specified range(s).
724 // Verify that the MemRegions specified in the argument array are within the
725 // reserved heap.
726 bool check_archive_addresses(MemRegion* range, size_t count);
727
728 // Commit the appropriate G1 regions containing the specified MemRegions
729 // and mark them as 'archive' regions. The regions in the array must be
730 // non-overlapping and in order of ascending address.
731 bool alloc_archive_regions(MemRegion* range, size_t count, bool open);
732
733 // Insert any required filler objects in the G1 regions around the specified
734 // ranges to make the regions parseable. This must be called after
735 // alloc_archive_regions, and after class loading has occurred.
736 void fill_archive_regions(MemRegion* range, size_t count);
737
738 // Populate the G1BlockOffsetTablePart for archived regions with the given
739 // memory ranges.
740 void populate_archive_regions_bot_part(MemRegion* range, size_t count);
741
742 // For each of the specified MemRegions, uncommit the containing G1 regions
743 // which had been allocated by alloc_archive_regions. This should be called
744 // rather than fill_archive_regions at JVM init time if the archive file
745 // mapping failed, with the same non-overlapping and sorted MemRegion array.
746 void dealloc_archive_regions(MemRegion* range, size_t count);
747
748 private:
749
750 // Shrink the garbage-first heap by at most the given size (in bytes!).
751 // (Rounds down to a HeapRegion boundary.)
752 void shrink(size_t shrink_bytes);
753 void shrink_helper(size_t expand_bytes);
754
755 // Schedule the VM operation that will do an evacuation pause to
756 // satisfy an allocation request of word_size. *succeeded will
757 // return whether the VM operation was successful (it did do an
758 // evacuation pause) or not (another thread beat us to it or the GC
759 // locker was active). Given that we should not be holding the
760 // Heap_lock when we enter this method, we will pass the
761 // gc_count_before (i.e., total_collections()) as a parameter since
762 // it has to be read while holding the Heap_lock. Currently, both
763 // methods that call do_collection_pause() release the Heap_lock
764 // before the call, so it's easy to read gc_count_before just before.
765 HeapWord* do_collection_pause(size_t word_size,
766 uint gc_count_before,
767 bool* succeeded,
768 GCCause::Cause gc_cause);
769
770 // Perform an incremental collection at a safepoint, possibly
771 // followed by a by-policy upgrade to a full collection. Returns
772 // false if unable to do the collection due to the GC locker being
773 // active, true otherwise.
774 // precondition: at safepoint on VM thread
775 // precondition: !is_gc_active()
776 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
777
778 // Helper for do_collection_pause_at_safepoint, containing the guts
779 // of the incremental collection pause, executed by the vm thread.
780 void do_collection_pause_at_safepoint_helper(double target_pause_time_ms);
781
782 G1HeapVerifier::G1VerifyType young_collection_verify_type() const;
783 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type);
784 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type);
785
786 public:
787 // Start a concurrent cycle.
788 void start_concurrent_cycle(bool concurrent_operation_is_full_mark);
789
790 void prepare_tlabs_for_mutator();
791
792 void retire_tlabs();
793
794 void expand_heap_after_young_collection();
795 // Update object copying statistics.
796 void record_obj_copy_mem_stats();
797
798 private:
799 // The hot card cache for remembered set insertion optimization.
800 G1HotCardCache* _hot_card_cache;
801
802 // The g1 remembered set of the heap.
803 G1RemSet* _rem_set;
804 // Global card set configuration
805 G1CardSetConfiguration _card_set_config;
806
807 public:
808 // After a collection pause, reset eden and the collection set.
809 void clear_eden();
810 void clear_collection_set();
811
812 // Abandon the current collection set without recording policy
813 // statistics or updating free lists.
814 void abandon_collection_set(G1CollectionSet* collection_set);
815
816 // The concurrent marker (and the thread it runs in.)
817 G1ConcurrentMark* _cm;
818 G1ConcurrentMarkThread* _cm_thread;
819
820 // The concurrent refiner.
821 G1ConcurrentRefine* _cr;
822
823 // The parallel task queues
824 G1ScannerTasksQueueSet *_task_queues;
825
826 // ("Weak") Reference processing support.
827 //
828 // G1 has 2 instances of the reference processor class.
829 //
830 // One (_ref_processor_cm) handles reference object discovery and subsequent
831 // processing during concurrent marking cycles. Discovery is enabled/disabled
832 // at the start/end of a concurrent marking cycle.
833 //
834 // The other (_ref_processor_stw) handles reference object discovery and
835 // processing during incremental evacuation pauses and full GC pauses.
836 //
837 // ## Incremental evacuation pauses
838 //
839 // STW ref processor discovery is enabled/disabled at the start/end of an
840 // incremental evacuation pause. No particular handling of the CM ref
841 // processor is needed, apart from treating the discovered references as
842 // roots; CM discovery does not need to be temporarily disabled as all
843 // marking threads are paused during incremental evacuation pauses.
844 //
845 // ## Full GC pauses
846 //
847 // We abort any ongoing concurrent marking cycle, disable CM discovery, and
848 // temporarily substitute a new closure for the STW ref processor's
849 // _is_alive_non_header field (old value is restored after the full GC). Then
850 // STW ref processor discovery is enabled, and marking & compaction
851 // commences.
852
853 // The (stw) reference processor...
854 ReferenceProcessor* _ref_processor_stw;
855
856 // During reference object discovery, the _is_alive_non_header
857 // closure (if non-null) is applied to the referent object to
858 // determine whether the referent is live. If so then the
859 // reference object does not need to be 'discovered' and can
860 // be treated as a regular oop. This has the benefit of reducing
861 // the number of 'discovered' reference objects that need to
862 // be processed.
863 //
864 // Instance of the is_alive closure for embedding into the
865 // STW reference processor as the _is_alive_non_header field.
866 // Supplying a value for the _is_alive_non_header field is
867 // optional but doing so prevents unnecessary additions to
868 // the discovered lists during reference discovery.
869 G1STWIsAliveClosure _is_alive_closure_stw;
870
871 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw;
872
873 // The (concurrent marking) reference processor...
874 ReferenceProcessor* _ref_processor_cm;
875
876 // Instance of the concurrent mark is_alive closure for embedding
877 // into the Concurrent Marking reference processor as the
878 // _is_alive_non_header field. Supplying a value for the
879 // _is_alive_non_header field is optional but doing so prevents
880 // unnecessary additions to the discovered lists during reference
881 // discovery.
882 G1CMIsAliveClosure _is_alive_closure_cm;
883
884 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm;
885 public:
886
887 G1ScannerTasksQueueSet* task_queues() const;
888 G1ScannerTasksQueue* task_queue(uint i) const;
889
890 // Create a G1CollectedHeap.
891 // Must call the initialize method afterwards.
892 // May not return if something goes wrong.
893 G1CollectedHeap();
894
895 private:
896 jint initialize_concurrent_refinement();
897 jint initialize_service_thread();
898 public:
899 // Initialize the G1CollectedHeap to have the initial and
900 // maximum sizes and remembered and barrier sets
901 // specified by the policy object.
902 jint initialize() override;
903
904 // Returns whether concurrent mark threads (and the VM) are about to terminate.
905 bool concurrent_mark_is_terminating() const;
906
907 void stop() override;
908 void safepoint_synchronize_begin() override;
909 void safepoint_synchronize_end() override;
910
911 // Does operations required after initialization has been done.
912 void post_initialize() override;
913
914 // Initialize weak reference processing.
915 void ref_processing_init();
916
917 Name kind() const override {
918 return CollectedHeap::G1;
919 }
920
921 const char* name() const override {
922 return "G1";
923 }
924
925 const G1CollectorState* collector_state() const { return &_collector_state; }
926 G1CollectorState* collector_state() { return &_collector_state; }
927
928 // The current policy object for the collector.
929 G1Policy* policy() const { return _policy; }
930 // The remembered set.
931 G1RemSet* rem_set() const { return _rem_set; }
932
933 inline G1GCPhaseTimes* phase_times() const;
934
935 const G1CollectionSet* collection_set() const { return &_collection_set; }
936 G1CollectionSet* collection_set() { return &_collection_set; }
937
938 SoftRefPolicy* soft_ref_policy() override;
939
940 void initialize_serviceability() override;
941 MemoryUsage memory_usage() override;
942 GrowableArray<GCMemoryManager*> memory_managers() override;
943 GrowableArray<MemoryPool*> memory_pools() override;
944
945 void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) override;
946
947 // Apply the given closure on all cards in the Hot Card Cache, emptying it.
948 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id);
949
950 // The shared block offset table array.
951 G1BlockOffsetTable* bot() const { return _bot; }
952
953 // Reference Processing accessors
954
955 // The STW reference processor....
956 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
957
958 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; }
959 STWGCTimer* gc_timer_stw() const { return _gc_timer_stw; }
960
961 // The Concurrent Marking reference processor...
962 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
963
964 size_t unused_committed_regions_in_bytes() const;
965
966 size_t capacity() const override;
967 size_t used() const override;
968 // This should be called when we're not holding the heap lock. The
969 // result might be a bit inaccurate.
970 size_t used_unlocked() const;
971 size_t recalculate_used() const;
972
973 // These virtual functions do the actual allocation.
974 // Some heaps may offer a contiguous region for shared non-blocking
975 // allocation, via inlined code (by exporting the address of the top and
976 // end fields defining the extent of the contiguous allocation region.)
977 // But G1CollectedHeap doesn't yet support this.
978
979 bool is_maximal_no_gc() const override {
980 return _hrm.available() == 0;
981 }
982
983 // Returns true if an incremental GC should be upgrade to a full gc. This
984 // is done when there are no free regions and the heap can't be expanded.
985 bool should_upgrade_to_full_gc() const {
986 return is_maximal_no_gc() && num_free_regions() == 0;
987 }
988
989 // The current number of regions in the heap.
990 uint num_regions() const { return _hrm.length(); }
991
992 // The max number of regions reserved for the heap. Except for static array
993 // sizing purposes you probably want to use max_regions().
994 uint max_reserved_regions() const { return _hrm.reserved_length(); }
995
996 // Max number of regions that can be committed.
997 uint max_regions() const { return _hrm.max_length(); }
998
999 // The number of regions that are completely free.
1000 uint num_free_regions() const { return _hrm.num_free_regions(); }
1001
1002 // The number of regions that can be allocated into.
1003 uint num_free_or_available_regions() const { return num_free_regions() + _hrm.available(); }
1004
1005 MemoryUsage get_auxiliary_data_memory_usage() const {
1006 return _hrm.get_auxiliary_data_memory_usage();
1007 }
1008
1009 // The number of regions that are not completely free.
1010 uint num_used_regions() const { return num_regions() - num_free_regions(); }
1011
1012 #ifdef ASSERT
1013 bool is_on_master_free_list(HeapRegion* hr) {
1014 return _hrm.is_free(hr);
1015 }
1016 #endif // ASSERT
1017
1018 inline void old_set_add(HeapRegion* hr);
1019 inline void old_set_remove(HeapRegion* hr);
1020
1021 inline void archive_set_add(HeapRegion* hr);
1022
1023 size_t non_young_capacity_bytes() {
1024 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes;
1025 }
1026
1027 // Determine whether the given region is one that we are using as an
1028 // old GC alloc region.
1029 bool is_old_gc_alloc_region(HeapRegion* hr);
1030
1031 // Perform a collection of the heap; intended for use in implementing
1032 // "System.gc". This probably implies as full a collection as the
1033 // "CollectedHeap" supports.
1034 void collect(GCCause::Cause cause) override;
1035
1036 // Perform a collection of the heap with the given cause.
1037 // Returns whether this collection actually executed.
1038 bool try_collect(GCCause::Cause cause, const G1GCCounters& counters_before);
1039
1040 void start_concurrent_gc_for_metadata_allocation(GCCause::Cause gc_cause);
1041
1042 void remove_from_old_gen_sets(const uint old_regions_removed,
1043 const uint archive_regions_removed,
1044 const uint humongous_regions_removed);
1045 void prepend_to_freelist(FreeRegionList* list);
1046 void decrement_summary_bytes(size_t bytes);
1047
1048 bool is_in(const void* p) const override;
1049
1050 // Return "TRUE" iff the given object address is within the collection
1051 // set. Assumes that the reference points into the heap.
1052 inline bool is_in_cset(const HeapRegion *hr);
1053 inline bool is_in_cset(oop obj);
1054 inline bool is_in_cset(HeapWord* addr);
1055
1056 inline bool is_in_cset_or_humongous(const oop obj);
1057
1058 private:
1059 // This array is used for a quick test on whether a reference points into
1060 // the collection set or not. Each of the array's elements denotes whether the
1061 // corresponding region is in the collection set or not.
1062 G1HeapRegionAttrBiasedMappedArray _region_attr;
1063
1064 public:
1065
1066 inline G1HeapRegionAttr region_attr(const void* obj) const;
1067 inline G1HeapRegionAttr region_attr(uint idx) const;
1068
1069 MemRegion reserved() const {
1070 return _hrm.reserved();
1071 }
1072
1073 bool is_in_reserved(const void* addr) const {
1074 return reserved().contains(addr);
1075 }
1076
1077 G1HotCardCache* hot_card_cache() const { return _hot_card_cache; }
1078
1079 G1CardTable* card_table() const {
1080 return _card_table;
1081 }
1082
1083 // Iteration functions.
1084
1085 void object_iterate_parallel(ObjectClosure* cl, uint worker_id, HeapRegionClaimer* claimer);
1086
1087 // Iterate over all objects, calling "cl.do_object" on each.
1088 void object_iterate(ObjectClosure* cl) override;
1089
1090 ParallelObjectIteratorImpl* parallel_object_iterator(uint thread_num) override;
1091
1092 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1093 void keep_alive(oop obj) override;
1094
1095 // Iterate over heap regions, in address order, terminating the
1096 // iteration early if the "do_heap_region" method returns "true".
1097 void heap_region_iterate(HeapRegionClosure* blk) const;
1098
1099 // Return the region with the given index. It assumes the index is valid.
1100 inline HeapRegion* region_at(uint index) const;
1101 inline HeapRegion* region_at_or_null(uint index) const;
1102
1103 // Return the next region (by index) that is part of the same
1104 // humongous object that hr is part of.
1105 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
1106
1107 // Calculate the region index of the given address. Given address must be
1108 // within the heap.
1109 inline uint addr_to_region(HeapWord* addr) const;
1110
1111 inline HeapWord* bottom_addr_for_region(uint index) const;
1112
1113 // Two functions to iterate over the heap regions in parallel. Threads
1114 // compete using the HeapRegionClaimer to claim the regions before
1115 // applying the closure on them.
1116 // The _from_worker_offset version uses the HeapRegionClaimer and
1117 // the worker id to calculate a start offset to prevent all workers to
1118 // start from the point.
1119 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl,
1120 HeapRegionClaimer* hrclaimer,
1121 uint worker_id) const;
1122
1123 void heap_region_par_iterate_from_start(HeapRegionClosure* cl,
1124 HeapRegionClaimer* hrclaimer) const;
1125
1126 // Iterate over all regions in the collection set in parallel.
1127 void collection_set_par_iterate_all(HeapRegionClosure* cl,
1128 HeapRegionClaimer* hr_claimer,
1129 uint worker_id);
1130
1131 // Iterate over all regions currently in the current collection set.
1132 void collection_set_iterate_all(HeapRegionClosure* blk);
1133
1134 // Iterate over the regions in the current increment of the collection set.
1135 // Starts the iteration so that the start regions of a given worker id over the
1136 // set active_workers are evenly spread across the set of collection set regions
1137 // to be iterated.
1138 // The variant with the HeapRegionClaimer guarantees that the closure will be
1139 // applied to a particular region exactly once.
1140 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) {
1141 collection_set_iterate_increment_from(blk, NULL, worker_id);
1142 }
1143 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id);
1144 // Iterate over the array of region indexes, uint regions[length], applying
1145 // the given HeapRegionClosure on each region. The worker_id will determine where
1146 // to start the iteration to allow for more efficient parallel iteration.
1147 void par_iterate_regions_array(HeapRegionClosure* cl,
1148 HeapRegionClaimer* hr_claimer,
1149 const uint regions[],
1150 size_t length,
1151 uint worker_id) const;
1152
1153 // Returns the HeapRegion that contains addr. addr must not be NULL.
1154 template <class T>
1155 inline HeapRegion* heap_region_containing(const T addr) const;
1156
1157 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted
1158 // region. addr must not be NULL.
1159 template <class T>
1160 inline HeapRegion* heap_region_containing_or_null(const T addr) const;
1161
1162 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1163 // each address in the (reserved) heap is a member of exactly
1164 // one block. The defining characteristic of a block is that it is
1165 // possible to find its size, and thus to progress forward to the next
1166 // block. (Blocks may be of different sizes.) Thus, blocks may
1167 // represent Java objects, or they might be free blocks in a
1168 // free-list-based heap (or subheap), as long as the two kinds are
1169 // distinguishable and the size of each is determinable.
1170
1171 // Returns the address of the start of the "block" that contains the
1172 // address "addr". We say "blocks" instead of "object" since some heaps
1173 // may not pack objects densely; a chunk may either be an object or a
1174 // non-object.
1175 HeapWord* block_start(const void* addr) const;
1176
1177 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1178 // the block is an object.
1179 bool block_is_obj(const HeapWord* addr) const;
1180
1181 // Section on thread-local allocation buffers (TLABs)
1182 // See CollectedHeap for semantics.
1183
1184 size_t tlab_capacity(Thread* ignored) const override;
1185 size_t tlab_used(Thread* ignored) const override;
1186 size_t max_tlab_size() const override;
1187 size_t unsafe_max_tlab_alloc(Thread* ignored) const override;
1188
1189 inline bool is_in_young(const oop obj) const;
1190
1191 // Returns "true" iff the given word_size is "very large".
1192 static bool is_humongous(size_t word_size) {
1193 // Note this has to be strictly greater-than as the TLABs
1194 // are capped at the humongous threshold and we want to
1195 // ensure that we don't try to allocate a TLAB as
1196 // humongous and that we don't allocate a humongous
1197 // object in a TLAB.
1198 return word_size > _humongous_object_threshold_in_words;
1199 }
1200
1201 // Returns the humongous threshold for a specific region size
1202 static size_t humongous_threshold_for(size_t region_size) {
1203 return (region_size / 2);
1204 }
1205
1206 // Returns the number of regions the humongous object of the given word size
1207 // requires.
1208 static size_t humongous_obj_size_in_regions(size_t word_size);
1209
1210 // Print the maximum heap capacity.
1211 size_t max_capacity() const override;
1212
1213 Tickspan time_since_last_collection() const { return Ticks::now() - _collection_pause_end; }
1214
1215 // Convenience function to be used in situations where the heap type can be
1216 // asserted to be this type.
1217 static G1CollectedHeap* heap() {
1218 return named_heap<G1CollectedHeap>(CollectedHeap::G1);
1219 }
1220
1221 void set_region_short_lived_locked(HeapRegion* hr);
1222 // add appropriate methods for any other surv rate groups
1223
1224 G1SurvivorRegions* survivor() { return &_survivor; }
1225
1226 uint eden_regions_count() const { return _eden.length(); }
1227 uint eden_regions_count(uint node_index) const { return _eden.regions_on_node(node_index); }
1228 uint survivor_regions_count() const { return _survivor.length(); }
1229 uint survivor_regions_count(uint node_index) const { return _survivor.regions_on_node(node_index); }
1230 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); }
1231 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); }
1232 uint young_regions_count() const { return _eden.length() + _survivor.length(); }
1233 uint old_regions_count() const { return _old_set.length(); }
1234 uint archive_regions_count() const { return _archive_set.length(); }
1235 uint humongous_regions_count() const { return _humongous_set.length(); }
1236
1237 #ifdef ASSERT
1238 bool check_young_list_empty();
1239 #endif
1240
1241 bool is_marked_next(oop obj) const;
1242
1243 // Determine if an object is dead, given the object and also
1244 // the region to which the object belongs.
1245 inline bool is_obj_dead(const oop obj, const HeapRegion* hr) const;
1246
1247 // Determine if an object is dead, given only the object itself.
1248 // This will find the region to which the object belongs and
1249 // then call the region version of the same function.
1250
1251 // Added if it is NULL it isn't dead.
1252
1253 inline bool is_obj_dead(const oop obj) const;
1254
1255 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const;
1256 inline bool is_obj_dead_full(const oop obj) const;
1257
1258 // Mark the live object that failed evacuation in the prev bitmap.
1259 void mark_evac_failure_object(const oop obj, uint worker_id) const;
1260
1261 G1ConcurrentMark* concurrent_mark() const { return _cm; }
1262
1263 // Refinement
1264
1265 G1ConcurrentRefine* concurrent_refine() const { return _cr; }
1266
1267 // Optimized nmethod scanning support routines
1268
1269 // Register the given nmethod with the G1 heap.
1270 void register_nmethod(nmethod* nm) override;
1271
1272 // Unregister the given nmethod from the G1 heap.
1273 void unregister_nmethod(nmethod* nm) override;
1274
1275 // No nmethod flushing needed.
1276 void flush_nmethod(nmethod* nm) override {}
1277
1278 // No nmethod verification implemented.
1279 void verify_nmethod(nmethod* nm) override {}
1280
1281 // Recalculate amount of used memory after GC. Must be called after all allocation
1282 // has finished.
1283 void update_used_after_gc(bool evacuation_failed);
1284 // Reset and re-enable the hot card cache.
1285 // Note the counts for the cards in the regions in the
1286 // collection set are reset when the collection set is freed.
1287 void reset_hot_card_cache();
1288 // Free up superfluous code root memory.
1289 void purge_code_root_memory();
1290
1291 // Rebuild the code root lists for each region
1292 // after a full GC.
1293 void rebuild_code_roots();
1294
1295 // Performs cleaning of data structures after class unloading.
1296 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred);
1297
1298 // Verification
1299
1300 // Perform any cleanup actions necessary before allowing a verification.
1301 void prepare_for_verify() override;
1302
1303 // Perform verification.
1304
1305 // vo == UsePrevMarking -> use "prev" marking information,
1306 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
1307 //
1308 // NOTE: Only the "prev" marking information is guaranteed to be
1309 // consistent most of the time, so most calls to this should use
1310 // vo == UsePrevMarking.
1311 // Currently there is only one place where this is called with
1312 // vo == UseFullMarking, which is to verify the marking during a
1313 // full GC.
1314 void verify(VerifyOption vo) override;
1315
1316 // WhiteBox testing support.
1317 bool supports_concurrent_gc_breakpoints() const override;
1318
1319 WorkerThreads* safepoint_workers() override { return _workers; }
1320
1321 bool is_archived_object(oop object) const override;
1322
1323 // The methods below are here for convenience and dispatch the
1324 // appropriate method depending on value of the given VerifyOption
1325 // parameter. The values for that parameter, and their meanings,
1326 // are the same as those above.
1327
1328 bool is_obj_dead_cond(const oop obj,
1329 const HeapRegion* hr,
1330 const VerifyOption vo) const;
1331
1332 bool is_obj_dead_cond(const oop obj,
1333 const VerifyOption vo) const;
1334
1335 G1HeapSummary create_g1_heap_summary();
1336 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats);
1337
1338 // Printing
1339 private:
1340 void print_heap_regions() const;
1341 void print_regions_on(outputStream* st) const;
1342
1343 public:
1344 void print_on(outputStream* st) const override;
1345 void print_extended_on(outputStream* st) const override;
1346 void print_on_error(outputStream* st) const override;
1347
1348 void gc_threads_do(ThreadClosure* tc) const override;
1349
1350 // Override
1351 void print_tracing_info() const override;
1352
1353 // The following two methods are helpful for debugging RSet issues.
1354 void print_cset_rsets() PRODUCT_RETURN;
1355 void print_all_rsets() PRODUCT_RETURN;
1356
1357 // Used to print information about locations in the hs_err file.
1358 bool print_location(outputStream* st, void* addr) const override;
1359 };
1360
1361 // Scoped object that performs common pre- and post-gc heap printing operations.
1362 class G1HeapPrinterMark : public StackObj {
1363 G1CollectedHeap* _g1h;
1364 G1HeapTransition _heap_transition;
1365
1366 public:
1367 G1HeapPrinterMark(G1CollectedHeap* g1h);
1368 ~G1HeapPrinterMark();
1369 };
1370
1371 // Scoped object that performs common pre- and post-gc operations related to
1372 // JFR events.
1373 class G1JFRTracerMark : public StackObj {
1374 protected:
1375 STWGCTimer* _timer;
1376 GCTracer* _tracer;
1377
1378 public:
1379 G1JFRTracerMark(STWGCTimer* timer, GCTracer* tracer);
1380 ~G1JFRTracerMark();
1381 };
1382
1383 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP