1 /*
2 * Copyright (c) 2001, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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/g1CollectionSet.hpp"
32 #include "gc/g1/g1CollectorState.hpp"
33 #include "gc/g1/g1ConcurrentMark.hpp"
34 #include "gc/g1/g1EdenRegions.hpp"
35 #include "gc/g1/g1EvacFailure.hpp"
36 #include "gc/g1/g1EvacStats.hpp"
37 #include "gc/g1/g1EvacuationInfo.hpp"
38 #include "gc/g1/g1GCPhaseTimes.hpp"
39 #include "gc/g1/g1HeapTransition.hpp"
40 #include "gc/g1/g1HeapVerifier.hpp"
41 #include "gc/g1/g1HRPrinter.hpp"
42 #include "gc/g1/g1HeapRegionAttr.hpp"
43 #include "gc/g1/g1MonitoringSupport.hpp"
44 #include "gc/g1/g1NUMA.hpp"
45 #include "gc/g1/g1RedirtyCardsQueue.hpp"
46 #include "gc/g1/g1SurvivorRegions.hpp"
47 #include "gc/g1/g1YCTypes.hpp"
48 #include "gc/g1/heapRegionManager.hpp"
49 #include "gc/g1/heapRegionSet.hpp"
50 #include "gc/g1/heterogeneousHeapRegionManager.hpp"
51 #include "gc/shared/barrierSet.hpp"
52 #include "gc/shared/collectedHeap.hpp"
53 #include "gc/shared/gcHeapSummary.hpp"
54 #include "gc/shared/plab.hpp"
55 #include "gc/shared/preservedMarks.hpp"
56 #include "gc/shared/softRefPolicy.hpp"
57 #include "gc/shared/taskqueue.hpp"
58 #include "memory/memRegion.hpp"
59 #include "utilities/stack.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 HeapRegion;
68 class GenerationSpec;
69 class G1ParScanThreadState;
70 class G1ParScanThreadStateSet;
71 class G1ParScanThreadState;
72 class MemoryPool;
73 class MemoryManager;
74 class ObjectClosure;
75 class SpaceClosure;
76 class CompactibleSpaceClosure;
77 class Space;
78 class G1CardTableEntryClosure;
79 class G1CollectionSet;
80 class G1Policy;
81 class G1HotCardCache;
82 class G1RemSet;
83 class G1YoungRemSetSamplingThread;
84 class G1ConcurrentMark;
85 class G1ConcurrentMarkThread;
86 class G1ConcurrentRefine;
87 class GenerationCounters;
88 class STWGCTimer;
89 class G1NewTracer;
90 class EvacuationFailedInfo;
91 class nmethod;
92 class WorkGang;
93 class G1Allocator;
94 class G1ArchiveAllocator;
95 class G1FullGCScope;
96 class G1HeapVerifier;
97 class G1HeapSizingPolicy;
98 class G1HeapSummary;
99 class G1EvacSummary;
100
101 typedef OverflowTaskQueue<ScannerTask, mtGC> G1ScannerTasksQueue;
102 typedef GenericTaskQueueSet<G1ScannerTasksQueue, mtGC> G1ScannerTasksQueueSet;
103
104 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() )
105 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
106
107 // The G1 STW is alive closure.
108 // An instance is embedded into the G1CH and used as the
109 // (optional) _is_alive_non_header closure in the STW
110 // reference processor. It is also extensively used during
111 // reference processing during STW evacuation pauses.
112 class G1STWIsAliveClosure : public BoolObjectClosure {
113 G1CollectedHeap* _g1h;
114 public:
115 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
116 bool do_object_b(oop p);
117 };
118
119 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure {
120 G1CollectedHeap* _g1h;
121 public:
122 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
123 bool do_object_b(oop p);
124 };
125
126 class G1RegionMappingChangedListener : public G1MappingChangedListener {
127 private:
128 void reset_from_card_cache(uint start_idx, size_t num_regions);
129 public:
130 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
131 };
132
133 class G1CollectedHeap : public CollectedHeap {
134 friend class VM_CollectForMetadataAllocation;
135 friend class VM_G1CollectForAllocation;
136 friend class VM_G1CollectFull;
137 friend class VM_G1TryInitiateConcMark;
138 friend class VMStructs;
139 friend class MutatorAllocRegion;
140 friend class G1FullCollector;
141 friend class G1GCAllocRegion;
142 friend class G1HeapVerifier;
143
144 // Closures used in implementation.
145 friend class G1ParScanThreadState;
146 friend class G1ParScanThreadStateSet;
147 friend class G1EvacuateRegionsTask;
148 friend class G1PLABAllocator;
149
150 // Other related classes.
151 friend class HeapRegionClaimer;
152
153 // Testing classes.
154 friend class G1CheckRegionAttrTableClosure;
155
156 private:
157 G1YoungRemSetSamplingThread* _young_gen_sampling_thread;
158
159 WorkGang* _workers;
160 G1CardTable* _card_table;
161
162 SoftRefPolicy _soft_ref_policy;
163
164 static size_t _humongous_object_threshold_in_words;
165
166 // These sets keep track of old, archive and humongous regions respectively.
167 HeapRegionSet _old_set;
168 HeapRegionSet _archive_set;
169 HeapRegionSet _humongous_set;
170
171 void eagerly_reclaim_humongous_regions();
172 // Start a new incremental collection set for the next pause.
173 void start_new_collection_set();
174
175 // The block offset table for the G1 heap.
176 G1BlockOffsetTable* _bot;
177
178 // Tears down the region sets / lists so that they are empty and the
179 // regions on the heap do not belong to a region set / list. The
180 // only exception is the humongous set which we leave unaltered. If
181 // free_list_only is true, it will only tear down the master free
182 // list. It is called before a Full GC (free_list_only == false) or
183 // before heap shrinking (free_list_only == true).
184 void tear_down_region_sets(bool free_list_only);
185
186 // Rebuilds the region sets / lists so that they are repopulated to
187 // reflect the contents of the heap. The only exception is the
188 // humongous set which was not torn down in the first place. If
189 // free_list_only is true, it will only rebuild the master free
190 // list. It is called after a Full GC (free_list_only == false) or
191 // after heap shrinking (free_list_only == true).
192 void rebuild_region_sets(bool free_list_only);
193
194 // Callback for region mapping changed events.
195 G1RegionMappingChangedListener _listener;
196
197 // Handle G1 NUMA support.
198 G1NUMA* _numa;
199
200 // The sequence of all heap regions in the heap.
201 HeapRegionManager* _hrm;
202
203 // Manages all allocations with regions except humongous object allocations.
204 G1Allocator* _allocator;
205
206 // Manages all heap verification.
207 G1HeapVerifier* _verifier;
208
209 // Outside of GC pauses, the number of bytes used in all regions other
210 // than the current allocation region(s).
211 volatile size_t _summary_bytes_used;
212
213 void increase_used(size_t bytes);
214 void decrease_used(size_t bytes);
215
216 void set_used(size_t bytes);
217
218 // Number of bytes used in all regions during GC. Typically changed when
219 // retiring a GC alloc region.
220 size_t _bytes_used_during_gc;
221
222 // Class that handles archive allocation ranges.
223 G1ArchiveAllocator* _archive_allocator;
224
225 // GC allocation statistics policy for survivors.
226 G1EvacStats _survivor_evac_stats;
227
228 // GC allocation statistics policy for tenured objects.
229 G1EvacStats _old_evac_stats;
230
231 // It specifies whether we should attempt to expand the heap after a
232 // region allocation failure. If heap expansion fails we set this to
233 // false so that we don't re-attempt the heap expansion (it's likely
234 // that subsequent expansion attempts will also fail if one fails).
235 // Currently, it is only consulted during GC and it's reset at the
236 // start of each GC.
237 bool _expand_heap_after_alloc_failure;
238
239 // Helper for monitoring and management support.
240 G1MonitoringSupport* _g1mm;
241
242 // Records whether the region at the given index is (still) a
243 // candidate for eager reclaim. Only valid for humongous start
244 // regions; other regions have unspecified values. Humongous start
245 // regions are initialized at start of collection pause, with
246 // candidates removed from the set as they are found reachable from
247 // roots or the young generation.
248 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> {
249 protected:
250 bool default_value() const { return false; }
251 public:
252 void clear() { G1BiasedMappedArray<bool>::clear(); }
253 void set_candidate(uint region, bool value) {
254 set_by_index(region, value);
255 }
256 bool is_candidate(uint region) {
257 return get_by_index(region);
258 }
259 };
260
261 HumongousReclaimCandidates _humongous_reclaim_candidates;
262 // Stores whether during humongous object registration we found candidate regions.
263 // If not, we can skip a few steps.
264 bool _has_humongous_reclaim_candidates;
265
266 G1HRPrinter _hr_printer;
267
268 // Return true if an explicit GC should start a concurrent cycle instead
269 // of doing a STW full GC. A concurrent cycle should be started if:
270 // (a) cause == _g1_humongous_allocation,
271 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent,
272 // (c) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent,
273 // (d) cause == _wb_conc_mark or _wb_breakpoint,
274 // (e) cause == _g1_periodic_collection and +G1PeriodicGCInvokesConcurrent.
275 bool should_do_concurrent_full_gc(GCCause::Cause cause);
276
277 // Attempt to start a concurrent cycle with the indicated cause.
278 // precondition: should_do_concurrent_full_gc(cause)
279 bool try_collect_concurrently(GCCause::Cause cause,
280 uint gc_counter,
281 uint old_marking_started_before);
282
283 // Return true if should upgrade to full gc after an incremental one.
284 bool should_upgrade_to_full_gc(GCCause::Cause cause);
285
286 // indicates whether we are in young or mixed GC mode
287 G1CollectorState _collector_state;
288
289 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
290 // concurrent cycles) we have started.
291 volatile uint _old_marking_cycles_started;
292
293 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
294 // concurrent cycles) we have completed.
295 volatile uint _old_marking_cycles_completed;
296
297 // This is a non-product method that is helpful for testing. It is
298 // called at the end of a GC and artificially expands the heap by
299 // allocating a number of dead regions. This way we can induce very
300 // frequent marking cycles and stress the cleanup / concurrent
301 // cleanup code more (as all the regions that will be allocated by
302 // this method will be found dead by the marking cycle).
303 void allocate_dummy_regions() PRODUCT_RETURN;
304
305 // If the HR printer is active, dump the state of the regions in the
306 // heap after a compaction.
307 void print_hrm_post_compaction();
308
309 // Create a memory mapper for auxiliary data structures of the given size and
310 // translation factor.
311 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description,
312 size_t size,
313 size_t translation_factor);
314
315 void trace_heap(GCWhen::Type when, const GCTracer* tracer);
316
317 // These are macros so that, if the assert fires, we get the correct
318 // line number, file, etc.
319
320 #define heap_locking_asserts_params(_extra_message_) \
321 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
322 (_extra_message_), \
323 BOOL_TO_STR(Heap_lock->owned_by_self()), \
324 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
325 BOOL_TO_STR(Thread::current()->is_VM_thread())
326
327 #define assert_heap_locked() \
328 do { \
329 assert(Heap_lock->owned_by_self(), \
330 heap_locking_asserts_params("should be holding the Heap_lock")); \
331 } while (0)
332
333 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
334 do { \
335 assert(Heap_lock->owned_by_self() || \
336 (SafepointSynchronize::is_at_safepoint() && \
337 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
338 heap_locking_asserts_params("should be holding the Heap_lock or " \
339 "should be at a safepoint")); \
340 } while (0)
341
342 #define assert_heap_locked_and_not_at_safepoint() \
343 do { \
344 assert(Heap_lock->owned_by_self() && \
345 !SafepointSynchronize::is_at_safepoint(), \
346 heap_locking_asserts_params("should be holding the Heap_lock and " \
347 "should not be at a safepoint")); \
348 } while (0)
349
350 #define assert_heap_not_locked() \
351 do { \
352 assert(!Heap_lock->owned_by_self(), \
353 heap_locking_asserts_params("should not be holding the Heap_lock")); \
354 } while (0)
355
356 #define assert_heap_not_locked_and_not_at_safepoint() \
357 do { \
358 assert(!Heap_lock->owned_by_self() && \
359 !SafepointSynchronize::is_at_safepoint(), \
360 heap_locking_asserts_params("should not be holding the Heap_lock and " \
361 "should not be at a safepoint")); \
362 } while (0)
363
364 #define assert_at_safepoint_on_vm_thread() \
365 do { \
366 assert_at_safepoint(); \
367 assert(Thread::current_or_null() != NULL, "no current thread"); \
368 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \
369 } while (0)
370
371 #ifdef ASSERT
372 #define assert_used_and_recalculate_used_equal(g1h) \
373 do { \
374 size_t cur_used_bytes = g1h->used(); \
375 size_t recal_used_bytes = g1h->recalculate_used(); \
376 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \
377 " same as recalculated used(" SIZE_FORMAT ").", \
378 cur_used_bytes, recal_used_bytes); \
379 } while (0)
380 #else
381 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0)
382 #endif
383
384 const char* young_gc_name() const;
385
386 // The young region list.
387 G1EdenRegions _eden;
388 G1SurvivorRegions _survivor;
389
390 STWGCTimer* _gc_timer_stw;
391
392 G1NewTracer* _gc_tracer_stw;
393
394 // The current policy object for the collector.
395 G1Policy* _policy;
396 G1HeapSizingPolicy* _heap_sizing_policy;
397
398 G1CollectionSet _collection_set;
399
400 // Try to allocate a single non-humongous HeapRegion sufficient for
401 // an allocation of the given word_size. If do_expand is true,
402 // attempt to expand the heap if necessary to satisfy the allocation
403 // request. 'type' takes the type of region to be allocated. (Use constants
404 // Old, Eden, Humongous, Survivor defined in HeapRegionType.)
405 HeapRegion* new_region(size_t word_size,
406 HeapRegionType type,
407 bool do_expand,
408 uint node_index = G1NUMA::AnyNodeIndex);
409
410 // Initialize a contiguous set of free regions of length num_regions
411 // and starting at index first so that they appear as a single
412 // humongous region.
413 HeapWord* humongous_obj_allocate_initialize_regions(HeapRegion* first_hr,
414 uint num_regions,
415 size_t word_size);
416
417 // Attempt to allocate a humongous object of the given size. Return
418 // NULL if unsuccessful.
419 HeapWord* humongous_obj_allocate(size_t word_size);
420
421 // The following two methods, allocate_new_tlab() and
422 // mem_allocate(), are the two main entry points from the runtime
423 // into the G1's allocation routines. They have the following
424 // assumptions:
425 //
426 // * They should both be called outside safepoints.
427 //
428 // * They should both be called without holding the Heap_lock.
429 //
430 // * All allocation requests for new TLABs should go to
431 // allocate_new_tlab().
432 //
433 // * All non-TLAB allocation requests should go to mem_allocate().
434 //
435 // * If either call cannot satisfy the allocation request using the
436 // current allocating region, they will try to get a new one. If
437 // this fails, they will attempt to do an evacuation pause and
438 // retry the allocation.
439 //
440 // * If all allocation attempts fail, even after trying to schedule
441 // an evacuation pause, allocate_new_tlab() will return NULL,
442 // whereas mem_allocate() will attempt a heap expansion and/or
443 // schedule a Full GC.
444 //
445 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
446 // should never be called with word_size being humongous. All
447 // humongous allocation requests should go to mem_allocate() which
448 // will satisfy them with a special path.
449
450 virtual HeapWord* allocate_new_tlab(size_t min_size,
451 size_t requested_size,
452 size_t* actual_size);
453
454 virtual HeapWord* mem_allocate(size_t word_size,
455 bool* gc_overhead_limit_was_exceeded);
456
457 // First-level mutator allocation attempt: try to allocate out of
458 // the mutator alloc region without taking the Heap_lock. This
459 // should only be used for non-humongous allocations.
460 inline HeapWord* attempt_allocation(size_t min_word_size,
461 size_t desired_word_size,
462 size_t* actual_word_size);
463
464 // Second-level mutator allocation attempt: take the Heap_lock and
465 // retry the allocation attempt, potentially scheduling a GC
466 // pause. This should only be used for non-humongous allocations.
467 HeapWord* attempt_allocation_slow(size_t word_size);
468
469 // Takes the Heap_lock and attempts a humongous allocation. It can
470 // potentially schedule a GC pause.
471 HeapWord* attempt_allocation_humongous(size_t word_size);
472
473 // Allocation attempt that should be called during safepoints (e.g.,
474 // at the end of a successful GC). expect_null_mutator_alloc_region
475 // specifies whether the mutator alloc region is expected to be NULL
476 // or not.
477 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
478 bool expect_null_mutator_alloc_region);
479
480 // These methods are the "callbacks" from the G1AllocRegion class.
481
482 // For mutator alloc regions.
483 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index);
484 void retire_mutator_alloc_region(HeapRegion* alloc_region,
485 size_t allocated_bytes);
486
487 // For GC alloc regions.
488 bool has_more_regions(G1HeapRegionAttr dest);
489 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest, uint node_index);
490 void retire_gc_alloc_region(HeapRegion* alloc_region,
491 size_t allocated_bytes, G1HeapRegionAttr dest);
492
493 // - if explicit_gc is true, the GC is for a System.gc() etc,
494 // otherwise it's for a failed allocation.
495 // - if clear_all_soft_refs is true, all soft references should be
496 // cleared during the GC.
497 // - it returns false if it is unable to do the collection due to the
498 // GC locker being active, true otherwise.
499 bool do_full_collection(bool explicit_gc,
500 bool clear_all_soft_refs);
501
502 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
503 virtual void do_full_collection(bool clear_all_soft_refs);
504
505 // Callback from VM_G1CollectForAllocation operation.
506 // This function does everything necessary/possible to satisfy a
507 // failed allocation request (including collection, expansion, etc.)
508 HeapWord* satisfy_failed_allocation(size_t word_size,
509 bool* succeeded);
510 // Internal helpers used during full GC to split it up to
511 // increase readability.
512 void abort_concurrent_cycle();
513 void verify_before_full_collection(bool explicit_gc);
514 void prepare_heap_for_full_collection();
515 void prepare_heap_for_mutators();
516 void abort_refinement();
517 void verify_after_full_collection();
518 void print_heap_after_full_collection(G1HeapTransition* heap_transition);
519
520 // Helper method for satisfy_failed_allocation()
521 HeapWord* satisfy_failed_allocation_helper(size_t word_size,
522 bool do_gc,
523 bool clear_all_soft_refs,
524 bool expect_null_mutator_alloc_region,
525 bool* gc_succeeded);
526
527 // Attempting to expand the heap sufficiently
528 // to support an allocation of the given "word_size". If
529 // successful, perform the allocation and return the address of the
530 // allocated block, or else "NULL".
531 HeapWord* expand_and_allocate(size_t word_size);
532
533 // Process any reference objects discovered.
534 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states);
535
536 // If during an initial mark pause we may install a pending list head which is not
537 // otherwise reachable ensure that it is marked in the bitmap for concurrent marking
538 // to discover.
539 void make_pending_list_reachable();
540
541 // Merges the information gathered on a per-thread basis for all worker threads
542 // during GC into global variables.
543 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states);
544
545 void verify_numa_regions(const char* desc);
546
547 public:
548 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; }
549
550 WorkGang* workers() const { return _workers; }
551
552 // Runs the given AbstractGangTask with the current active workers, returning the
553 // total time taken.
554 Tickspan run_task(AbstractGangTask* task);
555
556 G1Allocator* allocator() {
557 return _allocator;
558 }
559
560 G1HeapVerifier* verifier() {
561 return _verifier;
562 }
563
564 G1MonitoringSupport* g1mm() {
565 assert(_g1mm != NULL, "should have been initialized");
566 return _g1mm;
567 }
568
569 void resize_heap_after_full_collection();
570
571 G1NUMA* numa() const { return _numa; }
572
573 // Expand the garbage-first heap by at least the given size (in bytes!).
574 // Returns true if the heap was expanded by the requested amount;
575 // false otherwise.
576 // (Rounds up to a HeapRegion boundary.)
577 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL);
578 bool expand_single_region(uint node_index);
579
580 // Returns the PLAB statistics for a given destination.
581 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest);
582
583 // Determines PLAB size for a given destination.
584 inline size_t desired_plab_sz(G1HeapRegionAttr dest);
585
586 // Do anything common to GC's.
587 void gc_prologue(bool full);
588 void gc_epilogue(bool full);
589
590 // Does the given region fulfill remembered set based eager reclaim candidate requirements?
591 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const;
592
593 // Modify the reclaim candidate set and test for presence.
594 // These are only valid for starts_humongous regions.
595 inline void set_humongous_reclaim_candidate(uint region, bool value);
596 inline bool is_humongous_reclaim_candidate(uint region);
597 inline void set_has_humongous_reclaim_candidate(bool value);
598
599 // Remove from the reclaim candidate set. Also remove from the
600 // collection set so that later encounters avoid the slow path.
601 inline void set_humongous_is_live(oop obj);
602
603 // Register the given region to be part of the collection set.
604 inline void register_humongous_region_with_region_attr(uint index);
605
606 // We register a region with the fast "in collection set" test. We
607 // simply set to true the array slot corresponding to this region.
608 void register_young_region_with_region_attr(HeapRegion* r) {
609 _region_attr.set_in_young(r->hrm_index());
610 }
611 inline void register_region_with_region_attr(HeapRegion* r);
612 inline void register_old_region_with_region_attr(HeapRegion* r);
613 inline void register_optional_region_with_region_attr(HeapRegion* r);
614
615 void clear_region_attr(const HeapRegion* hr) {
616 _region_attr.clear(hr);
617 }
618
619 void clear_region_attr() {
620 _region_attr.clear();
621 }
622
623 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking
624 // for all regions.
625 void verify_region_attr_remset_update() PRODUCT_RETURN;
626
627 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause);
628
629 // This is called at the start of either a concurrent cycle or a Full
630 // GC to update the number of old marking cycles started.
631 void increment_old_marking_cycles_started();
632
633 // This is called at the end of either a concurrent cycle or a Full
634 // GC to update the number of old marking cycles completed. Those two
635 // can happen in a nested fashion, i.e., we start a concurrent
636 // cycle, a Full GC happens half-way through it which ends first,
637 // and then the cycle notices that a Full GC happened and ends
638 // too. The concurrent parameter is a boolean to help us do a bit
639 // tighter consistency checking in the method. If concurrent is
640 // false, the caller is the inner caller in the nesting (i.e., the
641 // Full GC). If concurrent is true, the caller is the outer caller
642 // in this nesting (i.e., the concurrent cycle). Further nesting is
643 // not currently supported. The end of this call also notifies
644 // the G1OldGCCount_lock in case a Java thread is waiting for a full
645 // GC to happen (e.g., it called System.gc() with
646 // +ExplicitGCInvokesConcurrent).
647 void increment_old_marking_cycles_completed(bool concurrent);
648
649 uint old_marking_cycles_completed() {
650 return _old_marking_cycles_completed;
651 }
652
653 G1HRPrinter* hr_printer() { return &_hr_printer; }
654
655 // Allocates a new heap region instance.
656 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr);
657
658 // Allocate the highest free region in the reserved heap. This will commit
659 // regions as necessary.
660 HeapRegion* alloc_highest_free_region();
661
662 // Frees a region by resetting its metadata and adding it to the free list
663 // passed as a parameter (this is usually a local list which will be appended
664 // to the master free list later or NULL if free list management is handled
665 // in another way).
666 // Callers must ensure they are the only one calling free on the given region
667 // at the same time.
668 void free_region(HeapRegion* hr, FreeRegionList* free_list);
669
670 // It dirties the cards that cover the block so that the post
671 // write barrier never queues anything when updating objects on this
672 // block. It is assumed (and in fact we assert) that the block
673 // belongs to a young region.
674 inline void dirty_young_block(HeapWord* start, size_t word_size);
675
676 // Frees a humongous region by collapsing it into individual regions
677 // and calling free_region() for each of them. The freed regions
678 // will be added to the free list that's passed as a parameter (this
679 // is usually a local list which will be appended to the master free
680 // list later).
681 // The method assumes that only a single thread is ever calling
682 // this for a particular region at once.
683 void free_humongous_region(HeapRegion* hr,
684 FreeRegionList* free_list);
685
686 // Facility for allocating in 'archive' regions in high heap memory and
687 // recording the allocated ranges. These should all be called from the
688 // VM thread at safepoints, without the heap lock held. They can be used
689 // to create and archive a set of heap regions which can be mapped at the
690 // same fixed addresses in a subsequent JVM invocation.
691 void begin_archive_alloc_range(bool open = false);
692
693 // Check if the requested size would be too large for an archive allocation.
694 bool is_archive_alloc_too_large(size_t word_size);
695
696 // Allocate memory of the requested size from the archive region. This will
697 // return NULL if the size is too large or if no memory is available. It
698 // does not trigger a garbage collection.
699 HeapWord* archive_mem_allocate(size_t word_size);
700
701 // Optionally aligns the end address and returns the allocated ranges in
702 // an array of MemRegions in order of ascending addresses.
703 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges,
704 size_t end_alignment_in_bytes = 0);
705
706 // Facility for allocating a fixed range within the heap and marking
707 // the containing regions as 'archive'. For use at JVM init time, when the
708 // caller may mmap archived heap data at the specified range(s).
709 // Verify that the MemRegions specified in the argument array are within the
710 // reserved heap.
711 bool check_archive_addresses(MemRegion* range, size_t count);
712
713 // Commit the appropriate G1 regions containing the specified MemRegions
714 // and mark them as 'archive' regions. The regions in the array must be
715 // non-overlapping and in order of ascending address.
716 bool alloc_archive_regions(MemRegion* range, size_t count, bool open);
717
718 // Insert any required filler objects in the G1 regions around the specified
719 // ranges to make the regions parseable. This must be called after
720 // alloc_archive_regions, and after class loading has occurred.
721 void fill_archive_regions(MemRegion* range, size_t count);
722
723 // For each of the specified MemRegions, uncommit the containing G1 regions
724 // which had been allocated by alloc_archive_regions. This should be called
725 // rather than fill_archive_regions at JVM init time if the archive file
726 // mapping failed, with the same non-overlapping and sorted MemRegion array.
727 void dealloc_archive_regions(MemRegion* range, size_t count);
728
729 oop materialize_archived_object(oop obj);
730
731 private:
732
733 // Shrink the garbage-first heap by at most the given size (in bytes!).
734 // (Rounds down to a HeapRegion boundary.)
735 void shrink(size_t expand_bytes);
736 void shrink_helper(size_t expand_bytes);
737
738 #if TASKQUEUE_STATS
739 static void print_taskqueue_stats_hdr(outputStream* const st);
740 void print_taskqueue_stats() const;
741 void reset_taskqueue_stats();
742 #endif // TASKQUEUE_STATS
743
744 // Schedule the VM operation that will do an evacuation pause to
745 // satisfy an allocation request of word_size. *succeeded will
746 // return whether the VM operation was successful (it did do an
747 // evacuation pause) or not (another thread beat us to it or the GC
748 // locker was active). Given that we should not be holding the
749 // Heap_lock when we enter this method, we will pass the
750 // gc_count_before (i.e., total_collections()) as a parameter since
751 // it has to be read while holding the Heap_lock. Currently, both
752 // methods that call do_collection_pause() release the Heap_lock
753 // before the call, so it's easy to read gc_count_before just before.
754 HeapWord* do_collection_pause(size_t word_size,
755 uint gc_count_before,
756 bool* succeeded,
757 GCCause::Cause gc_cause);
758
759 void wait_for_root_region_scanning();
760
761 // Perform an incremental collection at a safepoint, possibly
762 // followed by a by-policy upgrade to a full collection. Returns
763 // false if unable to do the collection due to the GC locker being
764 // active, true otherwise.
765 // precondition: at safepoint on VM thread
766 // precondition: !is_gc_active()
767 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
768
769 // Helper for do_collection_pause_at_safepoint, containing the guts
770 // of the incremental collection pause, executed by the vm thread.
771 void do_collection_pause_at_safepoint_helper(double target_pause_time_ms);
772
773 G1HeapVerifier::G1VerifyType young_collection_verify_type() const;
774 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type);
775 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type);
776
777 void calculate_collection_set(G1EvacuationInfo& evacuation_info, double target_pause_time_ms);
778
779 // Actually do the work of evacuating the parts of the collection set.
780 void evacuate_initial_collection_set(G1ParScanThreadStateSet* per_thread_states);
781 void evacuate_optional_collection_set(G1ParScanThreadStateSet* per_thread_states);
782 private:
783 // Evacuate the next set of optional regions.
784 void evacuate_next_optional_regions(G1ParScanThreadStateSet* per_thread_states);
785
786 public:
787 void pre_evacuate_collection_set(G1EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss);
788 void post_evacuate_collection_set(G1EvacuationInfo& evacuation_info,
789 G1RedirtyCardsQueueSet* rdcqs,
790 G1ParScanThreadStateSet* pss);
791
792 void resize_heap_after_young_gc();
793
794 // Update object copying statistics.
795 void record_obj_copy_mem_stats();
796
797 // The hot card cache for remembered set insertion optimization.
798 G1HotCardCache* _hot_card_cache;
799
800 // The g1 remembered set of the heap.
801 G1RemSet* _rem_set;
802
803 // After a collection pause, convert the regions in the collection set into free
804 // regions.
805 void free_collection_set(G1CollectionSet* collection_set, G1EvacuationInfo& evacuation_info, const size_t* surviving_young_words);
806
807 // Abandon the current collection set without recording policy
808 // statistics or updating free lists.
809 void abandon_collection_set(G1CollectionSet* collection_set);
810
811 // The concurrent marker (and the thread it runs in.)
812 G1ConcurrentMark* _cm;
813 G1ConcurrentMarkThread* _cm_thread;
814
815 // The concurrent refiner.
816 G1ConcurrentRefine* _cr;
817
818 // The parallel task queues
819 G1ScannerTasksQueueSet *_task_queues;
820
821 // True iff a evacuation has failed in the current collection.
822 bool _evacuation_failed;
823
824 EvacuationFailedInfo* _evacuation_failed_info_array;
825
826 // Failed evacuations cause some logical from-space objects to have
827 // forwarding pointers to themselves. Reset them.
828 void remove_self_forwarding_pointers(G1RedirtyCardsQueueSet* rdcqs);
829
830 // Restore the objects in the regions in the collection set after an
831 // evacuation failure.
832 void restore_after_evac_failure(G1RedirtyCardsQueueSet* rdcqs);
833
834 PreservedMarksSet _preserved_marks_set;
835
836 // Preserve the mark of "obj", if necessary, in preparation for its mark
837 // word being overwritten with a self-forwarding-pointer.
838 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markWord m);
839
840 #ifndef PRODUCT
841 // Support for forcing evacuation failures. Analogous to
842 // PromotionFailureALot for the other collectors.
843
844 // Records whether G1EvacuationFailureALot should be in effect
845 // for the current GC
846 bool _evacuation_failure_alot_for_current_gc;
847
848 // Used to record the GC number for interval checking when
849 // determining whether G1EvaucationFailureALot is in effect
850 // for the current GC.
851 size_t _evacuation_failure_alot_gc_number;
852
853 // Count of the number of evacuations between failures.
854 volatile size_t _evacuation_failure_alot_count;
855
856 // Set whether G1EvacuationFailureALot should be in effect
857 // for the current GC (based upon the type of GC and which
858 // command line flags are set);
859 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc,
860 bool during_initial_mark,
861 bool mark_or_rebuild_in_progress);
862
863 inline void set_evacuation_failure_alot_for_current_gc();
864
865 // Return true if it's time to cause an evacuation failure.
866 inline bool evacuation_should_fail();
867
868 // Reset the G1EvacuationFailureALot counters. Should be called at
869 // the end of an evacuation pause in which an evacuation failure occurred.
870 inline void reset_evacuation_should_fail();
871 #endif // !PRODUCT
872
873 // ("Weak") Reference processing support.
874 //
875 // G1 has 2 instances of the reference processor class. One
876 // (_ref_processor_cm) handles reference object discovery
877 // and subsequent processing during concurrent marking cycles.
878 //
879 // The other (_ref_processor_stw) handles reference object
880 // discovery and processing during full GCs and incremental
881 // evacuation pauses.
882 //
883 // During an incremental pause, reference discovery will be
884 // temporarily disabled for _ref_processor_cm and will be
885 // enabled for _ref_processor_stw. At the end of the evacuation
886 // pause references discovered by _ref_processor_stw will be
887 // processed and discovery will be disabled. The previous
888 // setting for reference object discovery for _ref_processor_cm
889 // will be re-instated.
890 //
891 // At the start of marking:
892 // * Discovery by the CM ref processor is verified to be inactive
893 // and it's discovered lists are empty.
894 // * Discovery by the CM ref processor is then enabled.
895 //
896 // At the end of marking:
897 // * Any references on the CM ref processor's discovered
898 // lists are processed (possibly MT).
899 //
900 // At the start of full GC we:
901 // * Disable discovery by the CM ref processor and
902 // empty CM ref processor's discovered lists
903 // (without processing any entries).
904 // * Verify that the STW ref processor is inactive and it's
905 // discovered lists are empty.
906 // * Temporarily set STW ref processor discovery as single threaded.
907 // * Temporarily clear the STW ref processor's _is_alive_non_header
908 // field.
909 // * Finally enable discovery by the STW ref processor.
910 //
911 // The STW ref processor is used to record any discovered
912 // references during the full GC.
913 //
914 // At the end of a full GC we:
915 // * Enqueue any reference objects discovered by the STW ref processor
916 // that have non-live referents. This has the side-effect of
917 // making the STW ref processor inactive by disabling discovery.
918 // * Verify that the CM ref processor is still inactive
919 // and no references have been placed on it's discovered
920 // lists (also checked as a precondition during initial marking).
921
922 // The (stw) reference processor...
923 ReferenceProcessor* _ref_processor_stw;
924
925 // During reference object discovery, the _is_alive_non_header
926 // closure (if non-null) is applied to the referent object to
927 // determine whether the referent is live. If so then the
928 // reference object does not need to be 'discovered' and can
929 // be treated as a regular oop. This has the benefit of reducing
930 // the number of 'discovered' reference objects that need to
931 // be processed.
932 //
933 // Instance of the is_alive closure for embedding into the
934 // STW reference processor as the _is_alive_non_header field.
935 // Supplying a value for the _is_alive_non_header field is
936 // optional but doing so prevents unnecessary additions to
937 // the discovered lists during reference discovery.
938 G1STWIsAliveClosure _is_alive_closure_stw;
939
940 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw;
941
942 // The (concurrent marking) reference processor...
943 ReferenceProcessor* _ref_processor_cm;
944
945 // Instance of the concurrent mark is_alive closure for embedding
946 // into the Concurrent Marking reference processor as the
947 // _is_alive_non_header field. Supplying a value for the
948 // _is_alive_non_header field is optional but doing so prevents
949 // unnecessary additions to the discovered lists during reference
950 // discovery.
951 G1CMIsAliveClosure _is_alive_closure_cm;
952
953 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm;
954 public:
955
956 G1ScannerTasksQueue* task_queue(uint i) const;
957
958 uint num_task_queues() const;
959
960 // Create a G1CollectedHeap.
961 // Must call the initialize method afterwards.
962 // May not return if something goes wrong.
963 G1CollectedHeap();
964
965 private:
966 jint initialize_concurrent_refinement();
967 jint initialize_young_gen_sampling_thread();
968 public:
969 // Initialize the G1CollectedHeap to have the initial and
970 // maximum sizes and remembered and barrier sets
971 // specified by the policy object.
972 jint initialize();
973
974 virtual void stop();
975 virtual void safepoint_synchronize_begin();
976 virtual void safepoint_synchronize_end();
977
978 // Does operations required after initialization has been done.
979 void post_initialize();
980
981 // Initialize weak reference processing.
982 void ref_processing_init();
983
984 virtual Name kind() const {
985 return CollectedHeap::G1;
986 }
987
988 virtual const char* name() const {
989 return "G1";
990 }
991
992 const G1CollectorState* collector_state() const { return &_collector_state; }
993 G1CollectorState* collector_state() { return &_collector_state; }
994
995 // The current policy object for the collector.
996 G1Policy* policy() const { return _policy; }
997 // The remembered set.
998 G1RemSet* rem_set() const { return _rem_set; }
999
1000 inline G1GCPhaseTimes* phase_times() const;
1001
1002 HeapRegionManager* hrm() const { return _hrm; }
1003
1004 const G1CollectionSet* collection_set() const { return &_collection_set; }
1005 G1CollectionSet* collection_set() { return &_collection_set; }
1006
1007 virtual SoftRefPolicy* soft_ref_policy();
1008
1009 virtual void initialize_serviceability();
1010 virtual MemoryUsage memory_usage();
1011 virtual GrowableArray<GCMemoryManager*> memory_managers();
1012 virtual GrowableArray<MemoryPool*> memory_pools();
1013
1014 // Try to minimize the remembered set.
1015 void scrub_rem_set();
1016
1017 // Apply the given closure on all cards in the Hot Card Cache, emptying it.
1018 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id);
1019
1020 // The shared block offset table array.
1021 G1BlockOffsetTable* bot() const { return _bot; }
1022
1023 // Reference Processing accessors
1024
1025 // The STW reference processor....
1026 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
1027
1028 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; }
1029
1030 // The Concurrent Marking reference processor...
1031 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
1032
1033 size_t unused_committed_regions_in_bytes() const;
1034
1035 virtual size_t capacity() const;
1036 virtual size_t used() const;
1037 // This should be called when we're not holding the heap lock. The
1038 // result might be a bit inaccurate.
1039 size_t used_unlocked() const;
1040 size_t recalculate_used() const;
1041
1042 // These virtual functions do the actual allocation.
1043 // Some heaps may offer a contiguous region for shared non-blocking
1044 // allocation, via inlined code (by exporting the address of the top and
1045 // end fields defining the extent of the contiguous allocation region.)
1046 // But G1CollectedHeap doesn't yet support this.
1047
1048 virtual bool is_maximal_no_gc() const {
1049 return _hrm->available() == 0;
1050 }
1051
1052 // Returns whether there are any regions left in the heap for allocation.
1053 bool has_regions_left_for_allocation() const {
1054 return !is_maximal_no_gc() || num_free_regions() != 0;
1055 }
1056
1057 // The current number of regions in the heap.
1058 uint num_regions() const { return _hrm->length(); }
1059
1060 // The max number of regions in the heap.
1061 uint max_regions() const { return _hrm->max_length(); }
1062
1063 // Max number of regions that can be comitted.
1064 uint max_expandable_regions() const { return _hrm->max_expandable_length(); }
1065
1066 // The number of regions that are completely free.
1067 uint num_free_regions() const { return _hrm->num_free_regions(); }
1068
1069 // The number of regions that can be allocated into.
1070 uint num_free_or_available_regions() const { return num_free_regions() + _hrm->available(); }
1071
1072 MemoryUsage get_auxiliary_data_memory_usage() const {
1073 return _hrm->get_auxiliary_data_memory_usage();
1074 }
1075
1076 // The number of regions that are not completely free.
1077 uint num_used_regions() const { return num_regions() - num_free_regions(); }
1078
1079 #ifdef ASSERT
1080 bool is_on_master_free_list(HeapRegion* hr) {
1081 return _hrm->is_free(hr);
1082 }
1083 #endif // ASSERT
1084
1085 inline void old_set_add(HeapRegion* hr);
1086 inline void old_set_remove(HeapRegion* hr);
1087
1088 inline void archive_set_add(HeapRegion* hr);
1089
1090 size_t non_young_capacity_bytes() const {
1091 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes;
1092 }
1093
1094 // Determine whether the given region is one that we are using as an
1095 // old GC alloc region.
1096 bool is_old_gc_alloc_region(HeapRegion* hr);
1097
1098 // Perform a collection of the heap; intended for use in implementing
1099 // "System.gc". This probably implies as full a collection as the
1100 // "CollectedHeap" supports.
1101 virtual void collect(GCCause::Cause cause);
1102
1103 // Perform a collection of the heap with the given cause.
1104 // Returns whether this collection actually executed.
1105 bool try_collect(GCCause::Cause cause);
1106
1107 // True iff an evacuation has failed in the most-recent collection.
1108 bool evacuation_failed() { return _evacuation_failed; }
1109
1110 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed);
1111 void prepend_to_freelist(FreeRegionList* list);
1112 void decrement_summary_bytes(size_t bytes);
1113
1114 virtual bool is_in(const void* p) const;
1115 #ifdef ASSERT
1116 // Returns whether p is in one of the available areas of the heap. Slow but
1117 // extensive version.
1118 bool is_in_exact(const void* p) const;
1119 #endif
1120
1121 // Return "TRUE" iff the given object address is within the collection
1122 // set. Assumes that the reference points into the heap.
1123 inline bool is_in_cset(const HeapRegion *hr);
1124 inline bool is_in_cset(oop obj);
1125 inline bool is_in_cset(HeapWord* addr);
1126
1127 inline bool is_in_cset_or_humongous(const oop obj);
1128
1129 private:
1130 // This array is used for a quick test on whether a reference points into
1131 // the collection set or not. Each of the array's elements denotes whether the
1132 // corresponding region is in the collection set or not.
1133 G1HeapRegionAttrBiasedMappedArray _region_attr;
1134
1135 public:
1136
1137 inline G1HeapRegionAttr region_attr(const void* obj) const;
1138 inline G1HeapRegionAttr region_attr(uint idx) const;
1139
1140 // Return "TRUE" iff the given object address is in the reserved
1141 // region of g1.
1142 bool is_in_g1_reserved(const void* p) const {
1143 return _hrm->reserved().contains(p);
1144 }
1145
1146 // Returns a MemRegion that corresponds to the space that has been
1147 // reserved for the heap
1148 MemRegion g1_reserved() const {
1149 return _hrm->reserved();
1150 }
1151
1152 MemRegion reserved_region() const {
1153 return _reserved;
1154 }
1155
1156 HeapWord* base() const {
1157 return _reserved.start();
1158 }
1159
1160 bool is_in_reserved(const void* addr) const {
1161 return _reserved.contains(addr);
1162 }
1163
1164 G1HotCardCache* hot_card_cache() const { return _hot_card_cache; }
1165
1166 G1CardTable* card_table() const {
1167 return _card_table;
1168 }
1169
1170 // Iteration functions.
1171
1172 // Iterate over all objects, calling "cl.do_object" on each.
1173 virtual void object_iterate(ObjectClosure* cl);
1174
1175 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1176 virtual void keep_alive(oop obj);
1177
1178 // Iterate over heap regions, in address order, terminating the
1179 // iteration early if the "do_heap_region" method returns "true".
1180 void heap_region_iterate(HeapRegionClosure* blk) const;
1181
1182 // Return the region with the given index. It assumes the index is valid.
1183 inline HeapRegion* region_at(uint index) const;
1184 inline HeapRegion* region_at_or_null(uint index) const;
1185
1186 // Return the next region (by index) that is part of the same
1187 // humongous object that hr is part of.
1188 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
1189
1190 // Calculate the region index of the given address. Given address must be
1191 // within the heap.
1192 inline uint addr_to_region(HeapWord* addr) const;
1193
1194 inline HeapWord* bottom_addr_for_region(uint index) const;
1195
1196 // Two functions to iterate over the heap regions in parallel. Threads
1197 // compete using the HeapRegionClaimer to claim the regions before
1198 // applying the closure on them.
1199 // The _from_worker_offset version uses the HeapRegionClaimer and
1200 // the worker id to calculate a start offset to prevent all workers to
1201 // start from the point.
1202 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl,
1203 HeapRegionClaimer* hrclaimer,
1204 uint worker_id) const;
1205
1206 void heap_region_par_iterate_from_start(HeapRegionClosure* cl,
1207 HeapRegionClaimer* hrclaimer) const;
1208
1209 // Iterate over all regions in the collection set in parallel.
1210 void collection_set_par_iterate_all(HeapRegionClosure* cl,
1211 HeapRegionClaimer* hr_claimer,
1212 uint worker_id);
1213
1214 // Iterate over all regions currently in the current collection set.
1215 void collection_set_iterate_all(HeapRegionClosure* blk);
1216
1217 // Iterate over the regions in the current increment of the collection set.
1218 // Starts the iteration so that the start regions of a given worker id over the
1219 // set active_workers are evenly spread across the set of collection set regions
1220 // to be iterated.
1221 // The variant with the HeapRegionClaimer guarantees that the closure will be
1222 // applied to a particular region exactly once.
1223 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) {
1224 collection_set_iterate_increment_from(blk, NULL, worker_id);
1225 }
1226 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id);
1227
1228 // Returns the HeapRegion that contains addr. addr must not be NULL.
1229 template <class T>
1230 inline HeapRegion* heap_region_containing(const T addr) const;
1231
1232 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted
1233 // region. addr must not be NULL.
1234 template <class T>
1235 inline HeapRegion* heap_region_containing_or_null(const T addr) const;
1236
1237 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1238 // each address in the (reserved) heap is a member of exactly
1239 // one block. The defining characteristic of a block is that it is
1240 // possible to find its size, and thus to progress forward to the next
1241 // block. (Blocks may be of different sizes.) Thus, blocks may
1242 // represent Java objects, or they might be free blocks in a
1243 // free-list-based heap (or subheap), as long as the two kinds are
1244 // distinguishable and the size of each is determinable.
1245
1246 // Returns the address of the start of the "block" that contains the
1247 // address "addr". We say "blocks" instead of "object" since some heaps
1248 // may not pack objects densely; a chunk may either be an object or a
1249 // non-object.
1250 HeapWord* block_start(const void* addr) const;
1251
1252 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1253 // the block is an object.
1254 bool block_is_obj(const HeapWord* addr) const;
1255
1256 // Section on thread-local allocation buffers (TLABs)
1257 // See CollectedHeap for semantics.
1258
1259 bool supports_tlab_allocation() const;
1260 size_t tlab_capacity(Thread* ignored) const;
1261 size_t tlab_used(Thread* ignored) const;
1262 size_t max_tlab_size() const;
1263 size_t unsafe_max_tlab_alloc(Thread* ignored) const;
1264
1265 inline bool is_in_young(const oop obj);
1266
1267 // Returns "true" iff the given word_size is "very large".
1268 static bool is_humongous(size_t word_size) {
1269 // Note this has to be strictly greater-than as the TLABs
1270 // are capped at the humongous threshold and we want to
1271 // ensure that we don't try to allocate a TLAB as
1272 // humongous and that we don't allocate a humongous
1273 // object in a TLAB.
1274 return word_size > _humongous_object_threshold_in_words;
1275 }
1276
1277 // Returns the humongous threshold for a specific region size
1278 static size_t humongous_threshold_for(size_t region_size) {
1279 return (region_size / 2);
1280 }
1281
1282 // Returns the number of regions the humongous object of the given word size
1283 // requires.
1284 static size_t humongous_obj_size_in_regions(size_t word_size);
1285
1286 // Print the maximum heap capacity.
1287 virtual size_t max_capacity() const;
1288 virtual size_t min_capacity() const;
1289
1290 // Return the size of reserved memory. Returns different value than max_capacity() when AllocateOldGenAt is used.
1291 virtual size_t max_reserved_capacity() const;
1292
1293 // Print the soft maximum heap capacity.
1294 size_t soft_max_capacity() const;
1295
1296 virtual jlong millis_since_last_gc();
1297
1298
1299 // Convenience function to be used in situations where the heap type can be
1300 // asserted to be this type.
1301 static G1CollectedHeap* heap();
1302
1303 void set_region_short_lived_locked(HeapRegion* hr);
1304 // add appropriate methods for any other surv rate groups
1305
1306 const G1SurvivorRegions* survivor() const { return &_survivor; }
1307
1308 uint eden_regions_count() const { return _eden.length(); }
1309 uint eden_regions_count(uint node_index) const { return _eden.regions_on_node(node_index); }
1310 uint survivor_regions_count() const { return _survivor.length(); }
1311 uint survivor_regions_count(uint node_index) const { return _survivor.regions_on_node(node_index); }
1312 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); }
1313 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); }
1314 uint young_regions_count() const { return _eden.length() + _survivor.length(); }
1315 uint old_regions_count() const { return _old_set.length(); }
1316 uint archive_regions_count() const { return _archive_set.length(); }
1317 uint humongous_regions_count() const { return _humongous_set.length(); }
1318
1319 #ifdef ASSERT
1320 bool check_young_list_empty();
1321 #endif
1322
1323 // *** Stuff related to concurrent marking. It's not clear to me that so
1324 // many of these need to be public.
1325
1326 // The functions below are helper functions that a subclass of
1327 // "CollectedHeap" can use in the implementation of its virtual
1328 // functions.
1329 // This performs a concurrent marking of the live objects in a
1330 // bitmap off to the side.
1331 void do_concurrent_mark();
1332
1333 bool is_marked_next(oop obj) const;
1334
1335 // Determine if an object is dead, given the object and also
1336 // the region to which the object belongs. An object is dead
1337 // iff a) it was not allocated since the last mark, b) it
1338 // is not marked, and c) it is not in an archive region.
1339 bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
1340 return
1341 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) &&
1342 !hr->is_archive();
1343 }
1344
1345 // This function returns true when an object has been
1346 // around since the previous marking and hasn't yet
1347 // been marked during this marking, and is not in an archive region.
1348 bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
1349 return
1350 !hr->obj_allocated_since_next_marking(obj) &&
1351 !is_marked_next(obj) &&
1352 !hr->is_archive();
1353 }
1354
1355 // Determine if an object is dead, given only the object itself.
1356 // This will find the region to which the object belongs and
1357 // then call the region version of the same function.
1358
1359 // Added if it is NULL it isn't dead.
1360
1361 inline bool is_obj_dead(const oop obj) const;
1362
1363 inline bool is_obj_ill(const oop obj) const;
1364
1365 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const;
1366 inline bool is_obj_dead_full(const oop obj) const;
1367
1368 G1ConcurrentMark* concurrent_mark() const { return _cm; }
1369
1370 // Refinement
1371
1372 G1ConcurrentRefine* concurrent_refine() const { return _cr; }
1373
1374 // Optimized nmethod scanning support routines
1375
1376 // Register the given nmethod with the G1 heap.
1377 virtual void register_nmethod(nmethod* nm);
1378
1379 // Unregister the given nmethod from the G1 heap.
1380 virtual void unregister_nmethod(nmethod* nm);
1381
1382 // No nmethod flushing needed.
1383 virtual void flush_nmethod(nmethod* nm) {}
1384
1385 // No nmethod verification implemented.
1386 virtual void verify_nmethod(nmethod* nm) {}
1387
1388 // Free up superfluous code root memory.
1389 void purge_code_root_memory();
1390
1391 // Rebuild the strong code root lists for each region
1392 // after a full GC.
1393 void rebuild_strong_code_roots();
1394
1395 // Partial cleaning of VM internal data structures.
1396 void string_dedup_cleaning(BoolObjectClosure* is_alive,
1397 OopClosure* keep_alive,
1398 G1GCPhaseTimes* phase_times = NULL);
1399
1400 // Performs cleaning of data structures after class unloading.
1401 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred);
1402
1403 // Redirty logged cards in the refinement queue.
1404 void redirty_logged_cards(G1RedirtyCardsQueueSet* rdcqs);
1405
1406 // Verification
1407
1408 // Deduplicate the string
1409 virtual void deduplicate_string(oop str);
1410
1411 // Perform any cleanup actions necessary before allowing a verification.
1412 virtual void prepare_for_verify();
1413
1414 // Perform verification.
1415
1416 // vo == UsePrevMarking -> use "prev" marking information,
1417 // vo == UseNextMarking -> use "next" marking information
1418 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
1419 //
1420 // NOTE: Only the "prev" marking information is guaranteed to be
1421 // consistent most of the time, so most calls to this should use
1422 // vo == UsePrevMarking.
1423 // Currently, there is only one case where this is called with
1424 // vo == UseNextMarking, which is to verify the "next" marking
1425 // information at the end of remark.
1426 // Currently there is only one place where this is called with
1427 // vo == UseFullMarking, which is to verify the marking during a
1428 // full GC.
1429 void verify(VerifyOption vo);
1430
1431 // WhiteBox testing support.
1432 virtual bool supports_concurrent_gc_breakpoints() const;
1433 bool is_heterogeneous_heap() const;
1434
1435 virtual WorkGang* get_safepoint_workers() { return _workers; }
1436
1437 // The methods below are here for convenience and dispatch the
1438 // appropriate method depending on value of the given VerifyOption
1439 // parameter. The values for that parameter, and their meanings,
1440 // are the same as those above.
1441
1442 bool is_obj_dead_cond(const oop obj,
1443 const HeapRegion* hr,
1444 const VerifyOption vo) const;
1445
1446 bool is_obj_dead_cond(const oop obj,
1447 const VerifyOption vo) const;
1448
1449 G1HeapSummary create_g1_heap_summary();
1450 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats);
1451
1452 // Printing
1453 private:
1454 void print_heap_regions() const;
1455 void print_regions_on(outputStream* st) const;
1456
1457 public:
1458 virtual void print_on(outputStream* st) const;
1459 virtual void print_extended_on(outputStream* st) const;
1460 virtual void print_on_error(outputStream* st) const;
1461
1462 virtual void gc_threads_do(ThreadClosure* tc) const;
1463
1464 // Override
1465 void print_tracing_info() const;
1466
1467 // The following two methods are helpful for debugging RSet issues.
1468 void print_cset_rsets() PRODUCT_RETURN;
1469 void print_all_rsets() PRODUCT_RETURN;
1470
1471 // Used to print information about locations in the hs_err file.
1472 virtual bool print_location(outputStream* st, void* addr) const;
1473 };
1474
1475 class G1ParEvacuateFollowersClosure : public VoidClosure {
1476 private:
1477 double _start_term;
1478 double _term_time;
1479 size_t _term_attempts;
1480
1481 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); }
1482 void end_term_time() { _term_time += (os::elapsedTime() - _start_term); }
1483 protected:
1484 G1CollectedHeap* _g1h;
1485 G1ParScanThreadState* _par_scan_state;
1486 G1ScannerTasksQueueSet* _queues;
1487 TaskTerminator* _terminator;
1488 G1GCPhaseTimes::GCParPhases _phase;
1489
1490 G1ParScanThreadState* par_scan_state() { return _par_scan_state; }
1491 G1ScannerTasksQueueSet* queues() { return _queues; }
1492 TaskTerminator* terminator() { return _terminator; }
1493
1494 public:
1495 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h,
1496 G1ParScanThreadState* par_scan_state,
1497 G1ScannerTasksQueueSet* queues,
1498 TaskTerminator* terminator,
1499 G1GCPhaseTimes::GCParPhases phase)
1500 : _start_term(0.0), _term_time(0.0), _term_attempts(0),
1501 _g1h(g1h), _par_scan_state(par_scan_state),
1502 _queues(queues), _terminator(terminator), _phase(phase) {}
1503
1504 void do_void();
1505
1506 double term_time() const { return _term_time; }
1507 size_t term_attempts() const { return _term_attempts; }
1508
1509 private:
1510 inline bool offer_termination();
1511 };
1512
1513 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP