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