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