1 /*
2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_G1_G1COLLECTEDHEAP_HPP
26 #define SHARE_VM_GC_G1_G1COLLECTEDHEAP_HPP
27
28 #include "gc/g1/evacuationInfo.hpp"
29 #include "gc/g1/g1BarrierSet.hpp"
30 #include "gc/g1/g1BiasedArray.hpp"
31 #include "gc/g1/g1CardTable.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/g1EvacFailure.hpp"
37 #include "gc/g1/g1EvacStats.hpp"
38 #include "gc/g1/g1HeapTransition.hpp"
39 #include "gc/g1/g1HeapVerifier.hpp"
40 #include "gc/g1/g1HRPrinter.hpp"
41 #include "gc/g1/g1InCSetState.hpp"
42 #include "gc/g1/g1MonitoringSupport.hpp"
43 #include "gc/g1/g1SurvivorRegions.hpp"
44 #include "gc/g1/g1YCTypes.hpp"
45 #include "gc/g1/heapRegionManager.hpp"
46 #include "gc/g1/heapRegionSet.hpp"
47 #include "gc/shared/barrierSet.hpp"
48 #include "gc/shared/collectedHeap.hpp"
49 #include "gc/shared/gcHeapSummary.hpp"
50 #include "gc/shared/plab.hpp"
51 #include "gc/shared/preservedMarks.hpp"
52 #include "gc/shared/softRefPolicy.hpp"
53 #include "memory/memRegion.hpp"
54 #include "services/memoryManager.hpp"
55 #include "utilities/stack.hpp"
56
57 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
58 // It uses the "Garbage First" heap organization and algorithm, which
59 // may combine concurrent marking with parallel, incremental compaction of
60 // heap subsets that will yield large amounts of garbage.
61
62 // Forward declarations
63 class HeapRegion;
64 class HRRSCleanupTask;
65 class GenerationSpec;
66 class G1ParScanThreadState;
67 class G1ParScanThreadStateSet;
68 class G1ParScanThreadState;
69 class MemoryPool;
70 class ObjectClosure;
71 class SpaceClosure;
72 class CompactibleSpaceClosure;
73 class Space;
74 class G1CollectionSet;
75 class G1CollectorPolicy;
76 class G1Policy;
77 class G1HotCardCache;
78 class G1RemSet;
79 class G1YoungRemSetSamplingThread;
80 class HeapRegionRemSetIterator;
81 class G1ConcurrentMark;
82 class G1ConcurrentMarkThread;
83 class G1ConcurrentRefine;
84 class GenerationCounters;
85 class STWGCTimer;
86 class G1NewTracer;
87 class EvacuationFailedInfo;
88 class nmethod;
89 class Ticks;
90 class WorkGang;
91 class G1Allocator;
92 class G1ArchiveAllocator;
93 class G1FullGCScope;
94 class G1HeapVerifier;
95 class G1HeapSizingPolicy;
96 class G1HeapSummary;
97 class G1EvacSummary;
98
99 typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue;
100 typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet;
101
102 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() )
103 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
104
105 // The G1 STW is alive closure.
106 // An instance is embedded into the G1CH and used as the
107 // (optional) _is_alive_non_header closure in the STW
108 // reference processor. It is also extensively used during
109 // reference processing during STW evacuation pauses.
110 class G1STWIsAliveClosure: public BoolObjectClosure {
111 G1CollectedHeap* _g1h;
112 public:
113 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
114 bool do_object_b(oop p);
115 };
116
117 class G1RegionMappingChangedListener : public G1MappingChangedListener {
118 private:
119 void reset_from_card_cache(uint start_idx, size_t num_regions);
120 public:
121 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
122 };
123
124 class G1CollectedHeap : public CollectedHeap {
125 friend class G1FreeCollectionSetTask;
126 friend class VM_CollectForMetadataAllocation;
127 friend class VM_G1CollectForAllocation;
128 friend class VM_G1CollectFull;
129 friend class VMStructs;
130 friend class MutatorAllocRegion;
131 friend class G1FullCollector;
132 friend class G1GCAllocRegion;
133 friend class G1HeapVerifier;
134
135 // Closures used in implementation.
136 friend class G1ParScanThreadState;
137 friend class G1ParScanThreadStateSet;
138 friend class G1ParTask;
139 friend class G1PLABAllocator;
140 friend class G1PrepareCompactClosure;
141
142 // Other related classes.
143 friend class HeapRegionClaimer;
144
145 // Testing classes.
146 friend class G1CheckCSetFastTableClosure;
147
148 private:
149 G1YoungRemSetSamplingThread* _young_gen_sampling_thread;
150
151 WorkGang* _workers;
152 G1CollectorPolicy* _collector_policy;
153 G1CardTable* _card_table;
154
155 SoftRefPolicy _soft_ref_policy;
156
157 GCMemoryManager _memory_manager;
158 GCMemoryManager _full_gc_memory_manager;
159
160 MemoryPool* _eden_pool;
161 MemoryPool* _survivor_pool;
162 MemoryPool* _old_pool;
163
164 static size_t _humongous_object_threshold_in_words;
165
166 // It keeps track of the old regions.
167 HeapRegionSet _old_set;
168
169 // It keeps track of the humongous regions.
170 HeapRegionSet _humongous_set;
171
172 virtual void initialize_serviceability();
173
174 void eagerly_reclaim_humongous_regions();
175 // Start a new incremental collection set for the next pause.
176 void start_new_collection_set();
177
178 // The number of regions we could create by expansion.
179 uint _expansion_regions;
180
181 // The block offset table for the G1 heap.
182 G1BlockOffsetTable* _bot;
183
184 // Tears down the region sets / lists so that they are empty and the
185 // regions on the heap do not belong to a region set / list. The
186 // only exception is the humongous set which we leave unaltered. If
187 // free_list_only is true, it will only tear down the master free
188 // list. It is called before a Full GC (free_list_only == false) or
189 // before heap shrinking (free_list_only == true).
190 void tear_down_region_sets(bool free_list_only);
191
192 // Rebuilds the region sets / lists so that they are repopulated to
193 // reflect the contents of the heap. The only exception is the
194 // humongous set which was not torn down in the first place. If
195 // free_list_only is true, it will only rebuild the master free
196 // list. It is called after a Full GC (free_list_only == false) or
197 // after heap shrinking (free_list_only == true).
198 void rebuild_region_sets(bool free_list_only);
199
200 // Callback for region mapping changed events.
201 G1RegionMappingChangedListener _listener;
202
203 // The sequence of all heap regions in the heap.
204 HeapRegionManager _hrm;
205
206 // Manages all allocations with regions except humongous object allocations.
207 G1Allocator* _allocator;
208
209 // Manages all heap verification.
210 G1HeapVerifier* _verifier;
211
212 // Outside of GC pauses, the number of bytes used in all regions other
213 // than the current allocation region(s).
214 size_t _summary_bytes_used;
215
216 void increase_used(size_t bytes);
217 void decrease_used(size_t bytes);
218
219 void set_used(size_t bytes);
220
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 // It specifies whether we should attempt to expand the heap after a
231 // region allocation failure. If heap expansion fails we set this to
232 // false so that we don't re-attempt the heap expansion (it's likely
233 // that subsequent expansion attempts will also fail if one fails).
234 // Currently, it is only consulted during GC and it's reset at the
235 // start of each GC.
236 bool _expand_heap_after_alloc_failure;
237
238 // Helper for monitoring and management support.
239 G1MonitoringSupport* _g1mm;
240
241 // Records whether the region at the given index is (still) a
242 // candidate for eager reclaim. Only valid for humongous start
243 // regions; other regions have unspecified values. Humongous start
244 // regions are initialized at start of collection pause, with
245 // candidates removed from the set as they are found reachable from
246 // roots or the young generation.
247 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> {
248 protected:
249 bool default_value() const { return false; }
250 public:
251 void clear() { G1BiasedMappedArray<bool>::clear(); }
252 void set_candidate(uint region, bool value) {
253 set_by_index(region, value);
254 }
255 bool is_candidate(uint region) {
256 return get_by_index(region);
257 }
258 };
259
260 HumongousReclaimCandidates _humongous_reclaim_candidates;
261 // Stores whether during humongous object registration we found candidate regions.
262 // If not, we can skip a few steps.
263 bool _has_humongous_reclaim_candidates;
264
265 G1HRPrinter _hr_printer;
266
267 // It decides whether an explicit GC should start a concurrent cycle
268 // instead of doing a STW GC. Currently, a concurrent cycle is
269 // explicitly started if:
270 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or
271 // (b) cause == _g1_humongous_allocation
272 // (c) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent.
273 // (d) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent.
274 // (e) cause == _wb_conc_mark
275 bool should_do_concurrent_full_gc(GCCause::Cause cause);
276
277 // indicates whether we are in young or mixed GC mode
278 G1CollectorState _collector_state;
279
280 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
281 // concurrent cycles) we have started.
282 volatile uint _old_marking_cycles_started;
283
284 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
285 // concurrent cycles) we have completed.
286 volatile uint _old_marking_cycles_completed;
287
288 // This is a non-product method that is helpful for testing. It is
289 // called at the end of a GC and artificially expands the heap by
290 // allocating a number of dead regions. This way we can induce very
291 // frequent marking cycles and stress the cleanup / concurrent
292 // cleanup code more (as all the regions that will be allocated by
293 // this method will be found dead by the marking cycle).
294 void allocate_dummy_regions() PRODUCT_RETURN;
295
296 // If the HR printer is active, dump the state of the regions in the
297 // heap after a compaction.
298 void print_hrm_post_compaction();
299
300 // Create a memory mapper for auxiliary data structures of the given size and
301 // translation factor.
302 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description,
303 size_t size,
304 size_t translation_factor);
305
306 void trace_heap(GCWhen::Type when, const GCTracer* tracer);
307
308 // These are macros so that, if the assert fires, we get the correct
309 // line number, file, etc.
310
311 #define heap_locking_asserts_params(_extra_message_) \
312 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
313 (_extra_message_), \
314 BOOL_TO_STR(Heap_lock->owned_by_self()), \
315 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
316 BOOL_TO_STR(Thread::current()->is_VM_thread())
317
318 #define assert_heap_locked() \
319 do { \
320 assert(Heap_lock->owned_by_self(), \
321 heap_locking_asserts_params("should be holding the Heap_lock")); \
322 } while (0)
323
324 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
325 do { \
326 assert(Heap_lock->owned_by_self() || \
327 (SafepointSynchronize::is_at_safepoint() && \
328 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
329 heap_locking_asserts_params("should be holding the Heap_lock or " \
330 "should be at a safepoint")); \
331 } while (0)
332
333 #define assert_heap_locked_and_not_at_safepoint() \
334 do { \
335 assert(Heap_lock->owned_by_self() && \
336 !SafepointSynchronize::is_at_safepoint(), \
337 heap_locking_asserts_params("should be holding the Heap_lock and " \
338 "should not be at a safepoint")); \
339 } while (0)
340
341 #define assert_heap_not_locked() \
342 do { \
343 assert(!Heap_lock->owned_by_self(), \
344 heap_locking_asserts_params("should not be holding the Heap_lock")); \
345 } while (0)
346
347 #define assert_heap_not_locked_and_not_at_safepoint() \
348 do { \
349 assert(!Heap_lock->owned_by_self() && \
350 !SafepointSynchronize::is_at_safepoint(), \
351 heap_locking_asserts_params("should not be holding the Heap_lock and " \
352 "should not be at a safepoint")); \
353 } while (0)
354
355 #define assert_at_safepoint_on_vm_thread() \
356 do { \
357 assert_at_safepoint(); \
358 assert(Thread::current_or_null() != NULL, "no current thread"); \
359 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \
360 } while (0)
361
362 // The young region list.
363 G1EdenRegions _eden;
364 G1SurvivorRegions _survivor;
365
366 STWGCTimer* _gc_timer_stw;
367
368 G1NewTracer* _gc_tracer_stw;
369
370 // The current policy object for the collector.
371 G1Policy* _g1_policy;
372 G1HeapSizingPolicy* _heap_sizing_policy;
373
374 G1CollectionSet _collection_set;
375
376 // Try to allocate a single non-humongous HeapRegion sufficient for
377 // an allocation of the given word_size. If do_expand is true,
378 // attempt to expand the heap if necessary to satisfy the allocation
379 // request. If the region is to be used as an old region or for a
380 // humongous object, set is_old to true. If not, to false.
381 HeapRegion* new_region(size_t word_size, bool is_old, bool do_expand);
382
383 // Initialize a contiguous set of free regions of length num_regions
384 // and starting at index first so that they appear as a single
385 // humongous region.
386 HeapWord* humongous_obj_allocate_initialize_regions(uint first,
387 uint num_regions,
388 size_t word_size);
389
390 // Attempt to allocate a humongous object of the given size. Return
391 // NULL if unsuccessful.
392 HeapWord* humongous_obj_allocate(size_t word_size);
393
394 // The following two methods, allocate_new_tlab() and
395 // mem_allocate(), are the two main entry points from the runtime
396 // into the G1's allocation routines. They have the following
397 // assumptions:
398 //
399 // * They should both be called outside safepoints.
400 //
401 // * They should both be called without holding the Heap_lock.
402 //
403 // * All allocation requests for new TLABs should go to
404 // allocate_new_tlab().
405 //
406 // * All non-TLAB allocation requests should go to mem_allocate().
407 //
408 // * If either call cannot satisfy the allocation request using the
409 // current allocating region, they will try to get a new one. If
410 // this fails, they will attempt to do an evacuation pause and
411 // retry the allocation.
412 //
413 // * If all allocation attempts fail, even after trying to schedule
414 // an evacuation pause, allocate_new_tlab() will return NULL,
415 // whereas mem_allocate() will attempt a heap expansion and/or
416 // schedule a Full GC.
417 //
418 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
419 // should never be called with word_size being humongous. All
420 // humongous allocation requests should go to mem_allocate() which
421 // will satisfy them with a special path.
422
423 virtual HeapWord* allocate_new_tlab(size_t min_word_size,
424 size_t desired_word_size,
425 size_t* actual_word_size);
426
427 virtual HeapWord* mem_allocate(size_t word_size,
428 bool* gc_overhead_limit_was_exceeded);
429
430 // First-level mutator allocation attempt: try to allocate out of
431 // the mutator alloc region without taking the Heap_lock. This
432 // should only be used for non-humongous allocations.
433 inline HeapWord* attempt_allocation(size_t min_word_size,
434 size_t desired_word_size,
435 size_t* actual_word_size);
436
437
438 // Second-level mutator allocation attempt: take the Heap_lock and
439 // retry the allocation attempt, potentially scheduling a GC
440 // pause. This should only be used for non-humongous allocations.
441 HeapWord* attempt_allocation_slow(size_t word_size);
442
443 // Takes the Heap_lock and attempts a humongous allocation. It can
444 // potentially schedule a GC pause.
445 HeapWord* attempt_allocation_humongous(size_t word_size);
446
447 // Allocation attempt that should be called during safepoints (e.g.,
448 // at the end of a successful GC). expect_null_mutator_alloc_region
449 // specifies whether the mutator alloc region is expected to be NULL
450 // or not.
451 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
452 bool expect_null_mutator_alloc_region);
453
454 // These methods are the "callbacks" from the G1AllocRegion class.
455
456 // For mutator alloc regions.
457 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force);
458 void retire_mutator_alloc_region(HeapRegion* alloc_region,
459 size_t allocated_bytes);
460
461 // For GC alloc regions.
462 bool has_more_regions(InCSetState dest);
463 HeapRegion* new_gc_alloc_region(size_t word_size, InCSetState dest);
464 void retire_gc_alloc_region(HeapRegion* alloc_region,
465 size_t allocated_bytes, InCSetState dest);
466
467 // - if explicit_gc is true, the GC is for a System.gc() etc,
468 // otherwise it's for a failed allocation.
469 // - if clear_all_soft_refs is true, all soft references should be
470 // cleared during the GC.
471 // - it returns false if it is unable to do the collection due to the
472 // GC locker being active, true otherwise.
473 bool do_full_collection(bool explicit_gc,
474 bool clear_all_soft_refs);
475
476 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
477 virtual void do_full_collection(bool clear_all_soft_refs);
478
479 // Resize the heap if necessary after a full collection.
480 void resize_if_necessary_after_full_collection();
481
482 // Callback from VM_G1CollectForAllocation operation.
483 // This function does everything necessary/possible to satisfy a
484 // failed allocation request (including collection, expansion, etc.)
485 HeapWord* satisfy_failed_allocation(size_t word_size,
486 bool* succeeded);
487 // Internal helpers used during full GC to split it up to
488 // increase readability.
489 void abort_concurrent_cycle();
490 void verify_before_full_collection(bool explicit_gc);
491 void prepare_heap_for_full_collection();
492 void prepare_heap_for_mutators();
493 void abort_refinement();
494 void verify_after_full_collection();
495 void print_heap_after_full_collection(G1HeapTransition* heap_transition);
496
497 // Helper method for satisfy_failed_allocation()
498 HeapWord* satisfy_failed_allocation_helper(size_t word_size,
499 bool do_gc,
500 bool clear_all_soft_refs,
501 bool expect_null_mutator_alloc_region,
502 bool* gc_succeeded);
503
504 // Attempting to expand the heap sufficiently
505 // to support an allocation of the given "word_size". If
506 // successful, perform the allocation and return the address of the
507 // allocated block, or else "NULL".
508 HeapWord* expand_and_allocate(size_t word_size);
509
510 // Preserve any referents discovered by concurrent marking that have not yet been
511 // copied by the STW pause.
512 void preserve_cm_referents(G1ParScanThreadStateSet* per_thread_states);
513 // Process any reference objects discovered during
514 // an incremental evacuation pause.
515 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states);
516
517 // Enqueue any remaining discovered references
518 // after processing.
519 void enqueue_discovered_references(G1ParScanThreadStateSet* per_thread_states);
520
521 // Merges the information gathered on a per-thread basis for all worker threads
522 // during GC into global variables.
523 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states);
524 public:
525 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; }
526
527 WorkGang* workers() const { return _workers; }
528
529 G1Allocator* allocator() {
530 return _allocator;
531 }
532
533 G1HeapVerifier* verifier() {
534 return _verifier;
535 }
536
537 G1MonitoringSupport* g1mm() {
538 assert(_g1mm != NULL, "should have been initialized");
539 return _g1mm;
540 }
541
542 // Expand the garbage-first heap by at least the given size (in bytes!).
543 // Returns true if the heap was expanded by the requested amount;
544 // false otherwise.
545 // (Rounds up to a HeapRegion boundary.)
546 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL);
547
548 // Returns the PLAB statistics for a given destination.
549 inline G1EvacStats* alloc_buffer_stats(InCSetState dest);
550
551 // Determines PLAB size for a given destination.
552 inline size_t desired_plab_sz(InCSetState dest);
553
554 // Do anything common to GC's.
555 void gc_prologue(bool full);
556 void gc_epilogue(bool full);
557
558 // Does the given region fulfill remembered set based eager reclaim candidate requirements?
559 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const;
560
561 // Modify the reclaim candidate set and test for presence.
562 // These are only valid for starts_humongous regions.
563 inline void set_humongous_reclaim_candidate(uint region, bool value);
564 inline bool is_humongous_reclaim_candidate(uint region);
565
566 // Remove from the reclaim candidate set. Also remove from the
567 // collection set so that later encounters avoid the slow path.
568 inline void set_humongous_is_live(oop obj);
569
570 // Register the given region to be part of the collection set.
571 inline void register_humongous_region_with_cset(uint index);
572 // Register regions with humongous objects (actually on the start region) in
573 // the in_cset_fast_test table.
574 void register_humongous_regions_with_cset();
575 // We register a region with the fast "in collection set" test. We
576 // simply set to true the array slot corresponding to this region.
577 void register_young_region_with_cset(HeapRegion* r) {
578 _in_cset_fast_test.set_in_young(r->hrm_index());
579 }
580 void register_old_region_with_cset(HeapRegion* r) {
581 _in_cset_fast_test.set_in_old(r->hrm_index());
582 }
583 void clear_in_cset(const HeapRegion* hr) {
584 _in_cset_fast_test.clear(hr);
585 }
586
587 void clear_cset_fast_test() {
588 _in_cset_fast_test.clear();
589 }
590
591 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause);
592
593 // This is called at the start of either a concurrent cycle or a Full
594 // GC to update the number of old marking cycles started.
595 void increment_old_marking_cycles_started();
596
597 // This is called at the end of either a concurrent cycle or a Full
598 // GC to update the number of old marking cycles completed. Those two
599 // can happen in a nested fashion, i.e., we start a concurrent
600 // cycle, a Full GC happens half-way through it which ends first,
601 // and then the cycle notices that a Full GC happened and ends
602 // too. The concurrent parameter is a boolean to help us do a bit
603 // tighter consistency checking in the method. If concurrent is
604 // false, the caller is the inner caller in the nesting (i.e., the
605 // Full GC). If concurrent is true, the caller is the outer caller
606 // in this nesting (i.e., the concurrent cycle). Further nesting is
607 // not currently supported. The end of this call also notifies
608 // the FullGCCount_lock in case a Java thread is waiting for a full
609 // GC to happen (e.g., it called System.gc() with
610 // +ExplicitGCInvokesConcurrent).
611 void increment_old_marking_cycles_completed(bool concurrent);
612
613 uint old_marking_cycles_completed() {
614 return _old_marking_cycles_completed;
615 }
616
617 G1HRPrinter* hr_printer() { return &_hr_printer; }
618
619 // Allocates a new heap region instance.
620 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr);
621
622 // Allocate the highest free region in the reserved heap. This will commit
623 // regions as necessary.
624 HeapRegion* alloc_highest_free_region();
625
626 // Frees a non-humongous region by initializing its contents and
627 // adding it to the free list that's passed as a parameter (this is
628 // usually a local list which will be appended to the master free
629 // list later). The used bytes of freed regions are accumulated in
630 // pre_used. If skip_remset is true, the region's RSet will not be freed
631 // up. If skip_hot_card_cache is true, the region's hot card cache will not
632 // be freed up. The assumption is that this will be done later.
633 // The locked parameter indicates if the caller has already taken
634 // care of proper synchronization. This may allow some optimizations.
635 void free_region(HeapRegion* hr,
636 FreeRegionList* free_list,
637 bool skip_remset,
638 bool skip_hot_card_cache = false,
639 bool locked = false);
640
641 // It dirties the cards that cover the block so that the post
642 // write barrier never queues anything when updating objects on this
643 // block. It is assumed (and in fact we assert) that the block
644 // belongs to a young region.
645 inline void dirty_young_block(HeapWord* start, size_t word_size);
646
647 // Frees a humongous region by collapsing it into individual regions
648 // and calling free_region() for each of them. The freed regions
649 // will be added to the free list that's passed as a parameter (this
650 // is usually a local list which will be appended to the master free
651 // list later).
652 // The method assumes that only a single thread is ever calling
653 // this for a particular region at once.
654 void free_humongous_region(HeapRegion* hr,
655 FreeRegionList* free_list);
656
657 // Facility for allocating in 'archive' regions in high heap memory and
658 // recording the allocated ranges. These should all be called from the
659 // VM thread at safepoints, without the heap lock held. They can be used
660 // to create and archive a set of heap regions which can be mapped at the
661 // same fixed addresses in a subsequent JVM invocation.
662 void begin_archive_alloc_range(bool open = false);
663
664 // Check if the requested size would be too large for an archive allocation.
665 bool is_archive_alloc_too_large(size_t word_size);
666
667 // Allocate memory of the requested size from the archive region. This will
668 // return NULL if the size is too large or if no memory is available. It
669 // does not trigger a garbage collection.
670 HeapWord* archive_mem_allocate(size_t word_size);
671
672 // Optionally aligns the end address and returns the allocated ranges in
673 // an array of MemRegions in order of ascending addresses.
674 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges,
675 size_t end_alignment_in_bytes = 0);
676
677 // Facility for allocating a fixed range within the heap and marking
678 // the containing regions as 'archive'. For use at JVM init time, when the
679 // caller may mmap archived heap data at the specified range(s).
680 // Verify that the MemRegions specified in the argument array are within the
681 // reserved heap.
682 bool check_archive_addresses(MemRegion* range, size_t count);
683
684 // Commit the appropriate G1 regions containing the specified MemRegions
685 // and mark them as 'archive' regions. The regions in the array must be
686 // non-overlapping and in order of ascending address.
687 bool alloc_archive_regions(MemRegion* range, size_t count, bool open);
688
689 // Insert any required filler objects in the G1 regions around the specified
690 // ranges to make the regions parseable. This must be called after
691 // alloc_archive_regions, and after class loading has occurred.
692 void fill_archive_regions(MemRegion* range, size_t count);
693
694 // For each of the specified MemRegions, uncommit the containing G1 regions
695 // which had been allocated by alloc_archive_regions. This should be called
696 // rather than fill_archive_regions at JVM init time if the archive file
697 // mapping failed, with the same non-overlapping and sorted MemRegion array.
698 void dealloc_archive_regions(MemRegion* range, size_t count);
699
700 private:
701
702 // Shrink the garbage-first heap by at most the given size (in bytes!).
703 // (Rounds down to a HeapRegion boundary.)
704 void shrink(size_t expand_bytes);
705 void shrink_helper(size_t expand_bytes);
706
707 #if TASKQUEUE_STATS
708 static void print_taskqueue_stats_hdr(outputStream* const st);
709 void print_taskqueue_stats() const;
710 void reset_taskqueue_stats();
711 #endif // TASKQUEUE_STATS
712
713 // Schedule the VM operation that will do an evacuation pause to
714 // satisfy an allocation request of word_size. *succeeded will
715 // return whether the VM operation was successful (it did do an
716 // evacuation pause) or not (another thread beat us to it or the GC
717 // locker was active). Given that we should not be holding the
718 // Heap_lock when we enter this method, we will pass the
719 // gc_count_before (i.e., total_collections()) as a parameter since
720 // it has to be read while holding the Heap_lock. Currently, both
721 // methods that call do_collection_pause() release the Heap_lock
722 // before the call, so it's easy to read gc_count_before just before.
723 HeapWord* do_collection_pause(size_t word_size,
724 uint gc_count_before,
725 bool* succeeded,
726 GCCause::Cause gc_cause);
727
728 void wait_for_root_region_scanning();
729
730 // The guts of the incremental collection pause, executed by the vm
731 // thread. It returns false if it is unable to do the collection due
732 // to the GC locker being active, true otherwise
733 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
734
735 // Actually do the work of evacuating the collection set.
736 void evacuate_collection_set(G1ParScanThreadStateSet* per_thread_states);
737
738 void pre_evacuate_collection_set();
739 void post_evacuate_collection_set(EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss);
740
741 // Print the header for the per-thread termination statistics.
742 static void print_termination_stats_hdr();
743 // Print actual per-thread termination statistics.
744 void print_termination_stats(uint worker_id,
745 double elapsed_ms,
746 double strong_roots_ms,
747 double term_ms,
748 size_t term_attempts,
749 size_t alloc_buffer_waste,
750 size_t undo_waste) const;
751 // Update object copying statistics.
752 void record_obj_copy_mem_stats();
753
754 // The hot card cache for remembered set insertion optimization.
755 G1HotCardCache* _hot_card_cache;
756
757 // The g1 remembered set of the heap.
758 G1RemSet* _g1_rem_set;
759
760 // A set of cards that cover the objects for which the Rsets should be updated
761 // concurrently after the collection.
762 DirtyCardQueueSet _dirty_card_queue_set;
763
764 // After a collection pause, convert the regions in the collection set into free
765 // regions.
766 void free_collection_set(G1CollectionSet* collection_set, EvacuationInfo& evacuation_info, const size_t* surviving_young_words);
767
768 // Abandon the current collection set without recording policy
769 // statistics or updating free lists.
770 void abandon_collection_set(G1CollectionSet* collection_set);
771
772 // The concurrent marker (and the thread it runs in.)
773 G1ConcurrentMark* _cm;
774 G1ConcurrentMarkThread* _cm_thread;
775
776 // The concurrent refiner.
777 G1ConcurrentRefine* _cr;
778
779 // The parallel task queues
780 RefToScanQueueSet *_task_queues;
781
782 // True iff a evacuation has failed in the current collection.
783 bool _evacuation_failed;
784
785 EvacuationFailedInfo* _evacuation_failed_info_array;
786
787 // Failed evacuations cause some logical from-space objects to have
788 // forwarding pointers to themselves. Reset them.
789 void remove_self_forwarding_pointers();
790
791 // Restore the objects in the regions in the collection set after an
792 // evacuation failure.
793 void restore_after_evac_failure();
794
795 PreservedMarksSet _preserved_marks_set;
796
797 // Preserve the mark of "obj", if necessary, in preparation for its mark
798 // word being overwritten with a self-forwarding-pointer.
799 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markOop m);
800
801 #ifndef PRODUCT
802 // Support for forcing evacuation failures. Analogous to
803 // PromotionFailureALot for the other collectors.
804
805 // Records whether G1EvacuationFailureALot should be in effect
806 // for the current GC
807 bool _evacuation_failure_alot_for_current_gc;
808
809 // Used to record the GC number for interval checking when
810 // determining whether G1EvaucationFailureALot is in effect
811 // for the current GC.
812 size_t _evacuation_failure_alot_gc_number;
813
814 // Count of the number of evacuations between failures.
815 volatile size_t _evacuation_failure_alot_count;
816
817 // Set whether G1EvacuationFailureALot should be in effect
818 // for the current GC (based upon the type of GC and which
819 // command line flags are set);
820 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc,
821 bool during_initial_mark,
822 bool mark_or_rebuild_in_progress);
823
824 inline void set_evacuation_failure_alot_for_current_gc();
825
826 // Return true if it's time to cause an evacuation failure.
827 inline bool evacuation_should_fail();
828
829 // Reset the G1EvacuationFailureALot counters. Should be called at
830 // the end of an evacuation pause in which an evacuation failure occurred.
831 inline void reset_evacuation_should_fail();
832 #endif // !PRODUCT
833
834 // ("Weak") Reference processing support.
835 //
836 // G1 has 2 instances of the reference processor class. One
837 // (_ref_processor_cm) handles reference object discovery
838 // and subsequent processing during concurrent marking cycles.
839 //
840 // The other (_ref_processor_stw) handles reference object
841 // discovery and processing during full GCs and incremental
842 // evacuation pauses.
843 //
844 // During an incremental pause, reference discovery will be
845 // temporarily disabled for _ref_processor_cm and will be
846 // enabled for _ref_processor_stw. At the end of the evacuation
847 // pause references discovered by _ref_processor_stw will be
848 // processed and discovery will be disabled. The previous
849 // setting for reference object discovery for _ref_processor_cm
850 // will be re-instated.
851 //
852 // At the start of marking:
853 // * Discovery by the CM ref processor is verified to be inactive
854 // and it's discovered lists are empty.
855 // * Discovery by the CM ref processor is then enabled.
856 //
857 // At the end of marking:
858 // * Any references on the CM ref processor's discovered
859 // lists are processed (possibly MT).
860 //
861 // At the start of full GC we:
862 // * Disable discovery by the CM ref processor and
863 // empty CM ref processor's discovered lists
864 // (without processing any entries).
865 // * Verify that the STW ref processor is inactive and it's
866 // discovered lists are empty.
867 // * Temporarily set STW ref processor discovery as single threaded.
868 // * Temporarily clear the STW ref processor's _is_alive_non_header
869 // field.
870 // * Finally enable discovery by the STW ref processor.
871 //
872 // The STW ref processor is used to record any discovered
873 // references during the full GC.
874 //
875 // At the end of a full GC we:
876 // * Enqueue any reference objects discovered by the STW ref processor
877 // that have non-live referents. This has the side-effect of
878 // making the STW ref processor inactive by disabling discovery.
879 // * Verify that the CM ref processor is still inactive
880 // and no references have been placed on it's discovered
881 // lists (also checked as a precondition during initial marking).
882
883 // The (stw) reference processor...
884 ReferenceProcessor* _ref_processor_stw;
885
886 // During reference object discovery, the _is_alive_non_header
887 // closure (if non-null) is applied to the referent object to
888 // determine whether the referent is live. If so then the
889 // reference object does not need to be 'discovered' and can
890 // be treated as a regular oop. This has the benefit of reducing
891 // the number of 'discovered' reference objects that need to
892 // be processed.
893 //
894 // Instance of the is_alive closure for embedding into the
895 // STW reference processor as the _is_alive_non_header field.
896 // Supplying a value for the _is_alive_non_header field is
897 // optional but doing so prevents unnecessary additions to
898 // the discovered lists during reference discovery.
899 G1STWIsAliveClosure _is_alive_closure_stw;
900
901 // The (concurrent marking) reference processor...
902 ReferenceProcessor* _ref_processor_cm;
903
904 // Instance of the concurrent mark is_alive closure for embedding
905 // into the Concurrent Marking reference processor as the
906 // _is_alive_non_header field. Supplying a value for the
907 // _is_alive_non_header field is optional but doing so prevents
908 // unnecessary additions to the discovered lists during reference
909 // discovery.
910 G1CMIsAliveClosure _is_alive_closure_cm;
911
912 public:
913
914 RefToScanQueue *task_queue(uint i) const;
915
916 uint num_task_queues() const;
917
918 // A set of cards where updates happened during the GC
919 DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
920
921 // Create a G1CollectedHeap with the specified policy.
922 // Must call the initialize method afterwards.
923 // May not return if something goes wrong.
924 G1CollectedHeap(G1CollectorPolicy* policy);
925
926 private:
927 jint initialize_concurrent_refinement();
928 jint initialize_young_gen_sampling_thread();
929 public:
930 // Initialize the G1CollectedHeap to have the initial and
931 // maximum sizes and remembered and barrier sets
932 // specified by the policy object.
933 jint initialize();
934
935 virtual void stop();
936 virtual void safepoint_synchronize_begin();
937 virtual void safepoint_synchronize_end();
938
939 // Return the (conservative) maximum heap alignment for any G1 heap
940 static size_t conservative_max_heap_alignment();
941
942 // Does operations required after initialization has been done.
943 void post_initialize();
944
945 // Initialize weak reference processing.
946 void ref_processing_init();
947
948 virtual Name kind() const {
949 return CollectedHeap::G1;
950 }
951
952 virtual const char* name() const {
953 return "G1";
954 }
955
956 const G1CollectorState* collector_state() const { return &_collector_state; }
957 G1CollectorState* collector_state() { return &_collector_state; }
958
959 // The current policy object for the collector.
960 G1Policy* g1_policy() const { return _g1_policy; }
961
962 const G1CollectionSet* collection_set() const { return &_collection_set; }
963 G1CollectionSet* collection_set() { return &_collection_set; }
964
965 virtual CollectorPolicy* collector_policy() const;
966
967 virtual SoftRefPolicy* soft_ref_policy();
968
969 virtual GrowableArray<GCMemoryManager*> memory_managers();
970 virtual GrowableArray<MemoryPool*> memory_pools();
971
972 // The rem set and barrier set.
973 G1RemSet* g1_rem_set() const { return _g1_rem_set; }
974
975 // Try to minimize the remembered set.
976 void scrub_rem_set();
977
978 // Apply the given closure on all cards in the Hot Card Cache, emptying it.
979 void iterate_hcc_closure(CardTableEntryClosure* cl, uint worker_i);
980
981 // Apply the given closure on all cards in the Dirty Card Queue Set, emptying it.
982 void iterate_dirty_card_closure(CardTableEntryClosure* cl, uint worker_i);
983
984 // The shared block offset table array.
985 G1BlockOffsetTable* bot() const { return _bot; }
986
987 // Reference Processing accessors
988
989 // The STW reference processor....
990 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
991
992 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; }
993
994 // The Concurrent Marking reference processor...
995 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
996
997 size_t unused_committed_regions_in_bytes() const;
998 virtual size_t capacity() const;
999 virtual size_t used() const;
1000 // This should be called when we're not holding the heap lock. The
1001 // result might be a bit inaccurate.
1002 size_t used_unlocked() const;
1003 size_t recalculate_used() const;
1004
1005 // These virtual functions do the actual allocation.
1006 // Some heaps may offer a contiguous region for shared non-blocking
1007 // allocation, via inlined code (by exporting the address of the top and
1008 // end fields defining the extent of the contiguous allocation region.)
1009 // But G1CollectedHeap doesn't yet support this.
1010
1011 virtual bool is_maximal_no_gc() const {
1012 return _hrm.available() == 0;
1013 }
1014
1015 // Returns whether there are any regions left in the heap for allocation.
1016 bool has_regions_left_for_allocation() const {
1017 return !is_maximal_no_gc() || num_free_regions() != 0;
1018 }
1019
1020 // The current number of regions in the heap.
1021 uint num_regions() const { return _hrm.length(); }
1022
1023 // The max number of regions in the heap.
1024 uint max_regions() const { return _hrm.max_length(); }
1025
1026 // The number of regions that are completely free.
1027 uint num_free_regions() const { return _hrm.num_free_regions(); }
1028
1029 MemoryUsage get_auxiliary_data_memory_usage() const {
1030 return _hrm.get_auxiliary_data_memory_usage();
1031 }
1032
1033 // The number of regions that are not completely free.
1034 uint num_used_regions() const { return num_regions() - num_free_regions(); }
1035
1036 #ifdef ASSERT
1037 bool is_on_master_free_list(HeapRegion* hr) {
1038 return _hrm.is_free(hr);
1039 }
1040 #endif // ASSERT
1041
1042 inline void old_set_add(HeapRegion* hr);
1043 inline void old_set_remove(HeapRegion* hr);
1044
1045 size_t non_young_capacity_bytes() {
1046 return (_old_set.length() + _humongous_set.length()) * HeapRegion::GrainBytes;
1047 }
1048
1049 // Determine whether the given region is one that we are using as an
1050 // old GC alloc region.
1051 bool is_old_gc_alloc_region(HeapRegion* hr);
1052
1053 // Perform a collection of the heap; intended for use in implementing
1054 // "System.gc". This probably implies as full a collection as the
1055 // "CollectedHeap" supports.
1056 virtual void collect(GCCause::Cause cause);
1057
1058 // True iff an evacuation has failed in the most-recent collection.
1059 bool evacuation_failed() { return _evacuation_failed; }
1060
1061 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed);
1062 void prepend_to_freelist(FreeRegionList* list);
1063 void decrement_summary_bytes(size_t bytes);
1064
1065 virtual bool is_in(const void* p) const;
1066 #ifdef ASSERT
1067 // Returns whether p is in one of the available areas of the heap. Slow but
1068 // extensive version.
1069 bool is_in_exact(const void* p) const;
1070 #endif
1071
1072 // Return "TRUE" iff the given object address is within the collection
1073 // set. Assumes that the reference points into the heap.
1074 inline bool is_in_cset(const HeapRegion *hr);
1075 inline bool is_in_cset(oop obj);
1076 inline bool is_in_cset(HeapWord* addr);
1077
1078 inline bool is_in_cset_or_humongous(const oop obj);
1079
1080 private:
1081 // This array is used for a quick test on whether a reference points into
1082 // the collection set or not. Each of the array's elements denotes whether the
1083 // corresponding region is in the collection set or not.
1084 G1InCSetStateFastTestBiasedMappedArray _in_cset_fast_test;
1085
1086 public:
1087
1088 inline InCSetState in_cset_state(const oop obj);
1089
1090 // Return "TRUE" iff the given object address is in the reserved
1091 // region of g1.
1092 bool is_in_g1_reserved(const void* p) const {
1093 return _hrm.reserved().contains(p);
1094 }
1095
1096 // Returns a MemRegion that corresponds to the space that has been
1097 // reserved for the heap
1098 MemRegion g1_reserved() const {
1099 return _hrm.reserved();
1100 }
1101
1102 virtual bool is_in_closed_subset(const void* p) const;
1103
1104 G1HotCardCache* g1_hot_card_cache() const { return _hot_card_cache; }
1105
1106 G1CardTable* card_table() const {
1107 return _card_table;
1108 }
1109
1110 // Iteration functions.
1111
1112 // Iterate over all objects, calling "cl.do_object" on each.
1113 virtual void object_iterate(ObjectClosure* cl);
1114
1115 virtual void safe_object_iterate(ObjectClosure* cl) {
1116 object_iterate(cl);
1117 }
1118
1119 // Iterate over heap regions, in address order, terminating the
1120 // iteration early if the "do_heap_region" method returns "true".
1121 void heap_region_iterate(HeapRegionClosure* blk) const;
1122
1123 // Return the region with the given index. It assumes the index is valid.
1124 inline HeapRegion* region_at(uint index) const;
1125
1126 // Return the next region (by index) that is part of the same
1127 // humongous object that hr is part of.
1128 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
1129
1130 // Calculate the region index of the given address. Given address must be
1131 // within the heap.
1132 inline uint addr_to_region(HeapWord* addr) const;
1133
1134 inline HeapWord* bottom_addr_for_region(uint index) const;
1135
1136 // Two functions to iterate over the heap regions in parallel. Threads
1137 // compete using the HeapRegionClaimer to claim the regions before
1138 // applying the closure on them.
1139 // The _from_worker_offset version uses the HeapRegionClaimer and
1140 // the worker id to calculate a start offset to prevent all workers to
1141 // start from the point.
1142 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl,
1143 HeapRegionClaimer* hrclaimer,
1144 uint worker_id) const;
1145
1146 void heap_region_par_iterate_from_start(HeapRegionClosure* cl,
1147 HeapRegionClaimer* hrclaimer) const;
1148
1149 // Iterate over the regions (if any) in the current collection set.
1150 void collection_set_iterate(HeapRegionClosure* blk);
1151
1152 // Iterate over the regions (if any) in the current collection set. Starts the
1153 // iteration over the entire collection set so that the start regions of a given
1154 // worker id over the set active_workers are evenly spread across the set of
1155 // collection set regions.
1156 void collection_set_iterate_from(HeapRegionClosure *blk, uint worker_id);
1157
1158 // Returns the HeapRegion that contains addr. addr must not be NULL.
1159 template <class T>
1160 inline HeapRegion* heap_region_containing(const T addr) const;
1161
1162 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1163 // each address in the (reserved) heap is a member of exactly
1164 // one block. The defining characteristic of a block is that it is
1165 // possible to find its size, and thus to progress forward to the next
1166 // block. (Blocks may be of different sizes.) Thus, blocks may
1167 // represent Java objects, or they might be free blocks in a
1168 // free-list-based heap (or subheap), as long as the two kinds are
1169 // distinguishable and the size of each is determinable.
1170
1171 // Returns the address of the start of the "block" that contains the
1172 // address "addr". We say "blocks" instead of "object" since some heaps
1173 // may not pack objects densely; a chunk may either be an object or a
1174 // non-object.
1175 virtual HeapWord* block_start(const void* addr) const;
1176
1177 // Requires "addr" to be the start of a chunk, and returns its size.
1178 // "addr + size" is required to be the start of a new chunk, or the end
1179 // of the active area of the heap.
1180 virtual size_t block_size(const HeapWord* addr) const;
1181
1182 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1183 // the block is an object.
1184 virtual bool block_is_obj(const HeapWord* addr) const;
1185
1186 // Section on thread-local allocation buffers (TLABs)
1187 // See CollectedHeap for semantics.
1188
1189 bool supports_tlab_allocation() const;
1190 size_t tlab_capacity(Thread* ignored) const;
1191 size_t tlab_used(Thread* ignored) const;
1192 size_t max_tlab_size() const;
1193 size_t unsafe_max_tlab_alloc(Thread* ignored) const;
1194
1195 inline bool is_in_young(const oop obj);
1196
1197 // Returns "true" iff the given word_size is "very large".
1198 static bool is_humongous(size_t word_size) {
1199 // Note this has to be strictly greater-than as the TLABs
1200 // are capped at the humongous threshold and we want to
1201 // ensure that we don't try to allocate a TLAB as
1202 // humongous and that we don't allocate a humongous
1203 // object in a TLAB.
1204 return word_size > _humongous_object_threshold_in_words;
1205 }
1206
1207 // Returns the humongous threshold for a specific region size
1208 static size_t humongous_threshold_for(size_t region_size) {
1209 return (region_size / 2);
1210 }
1211
1212 // Returns the number of regions the humongous object of the given word size
1213 // requires.
1214 static size_t humongous_obj_size_in_regions(size_t word_size);
1215
1216 // Print the maximum heap capacity.
1217 virtual size_t max_capacity() const;
1218
1219 virtual jlong millis_since_last_gc();
1220
1221
1222 // Convenience function to be used in situations where the heap type can be
1223 // asserted to be this type.
1224 static G1CollectedHeap* heap();
1225
1226 void set_region_short_lived_locked(HeapRegion* hr);
1227 // add appropriate methods for any other surv rate groups
1228
1229 const G1SurvivorRegions* survivor() const { return &_survivor; }
1230
1231 uint survivor_regions_count() const {
1232 return _survivor.length();
1233 }
1234
1235 uint eden_regions_count() const {
1236 return _eden.length();
1237 }
1238
1239 uint young_regions_count() const {
1240 return _eden.length() + _survivor.length();
1241 }
1242
1243 uint old_regions_count() const { return _old_set.length(); }
1244
1245 uint humongous_regions_count() const { return _humongous_set.length(); }
1246
1247 #ifdef ASSERT
1248 bool check_young_list_empty();
1249 #endif
1250
1251 // *** Stuff related to concurrent marking. It's not clear to me that so
1252 // many of these need to be public.
1253
1254 // The functions below are helper functions that a subclass of
1255 // "CollectedHeap" can use in the implementation of its virtual
1256 // functions.
1257 // This performs a concurrent marking of the live objects in a
1258 // bitmap off to the side.
1259 void do_concurrent_mark();
1260
1261 bool is_marked_next(oop obj) const;
1262
1263 // Determine if an object is dead, given the object and also
1264 // the region to which the object belongs. An object is dead
1265 // iff a) it was not allocated since the last mark, b) it
1266 // is not marked, and c) it is not in an archive region.
1267 bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
1268 return
1269 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) &&
1270 !hr->is_archive();
1271 }
1272
1273 // This function returns true when an object has been
1274 // around since the previous marking and hasn't yet
1275 // been marked during this marking, and is not in an archive region.
1276 bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
1277 return
1278 !hr->obj_allocated_since_next_marking(obj) &&
1279 !is_marked_next(obj) &&
1280 !hr->is_archive();
1281 }
1282
1283 // Determine if an object is dead, given only the object itself.
1284 // This will find the region to which the object belongs and
1285 // then call the region version of the same function.
1286
1287 // Added if it is NULL it isn't dead.
1288
1289 inline bool is_obj_dead(const oop obj) const;
1290
1291 inline bool is_obj_ill(const oop obj) const;
1292
1293 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const;
1294 inline bool is_obj_dead_full(const oop obj) const;
1295
1296 G1ConcurrentMark* concurrent_mark() const { return _cm; }
1297
1298 // Refinement
1299
1300 G1ConcurrentRefine* concurrent_refine() const { return _cr; }
1301
1302 // Optimized nmethod scanning support routines
1303
1304 // Is an oop scavengeable
1305 virtual bool is_scavengable(oop obj);
1306
1307 // Register the given nmethod with the G1 heap.
1308 virtual void register_nmethod(nmethod* nm);
1309
1310 // Unregister the given nmethod from the G1 heap.
1311 virtual void unregister_nmethod(nmethod* nm);
1312
1313 // Free up superfluous code root memory.
1314 void purge_code_root_memory();
1315
1316 // Rebuild the strong code root lists for each region
1317 // after a full GC.
1318 void rebuild_strong_code_roots();
1319
1320 // Partial cleaning used when class unloading is disabled.
1321 // Let the caller choose what structures to clean out:
1322 // - StringTable
1323 // - SymbolTable
1324 // - StringDeduplication structures
1325 void partial_cleaning(BoolObjectClosure* is_alive, bool unlink_strings, bool unlink_symbols, bool unlink_string_dedup);
1326
1327 // Complete cleaning used when class unloading is enabled.
1328 // Cleans out all structures handled by partial_cleaning and also the CodeCache.
1329 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred);
1330
1331 // Redirty logged cards in the refinement queue.
1332 void redirty_logged_cards();
1333 // Verification
1334
1335 // Perform any cleanup actions necessary before allowing a verification.
1336 virtual void prepare_for_verify();
1337
1338 // Perform verification.
1339
1340 // vo == UsePrevMarking -> use "prev" marking information,
1341 // vo == UseNextMarking -> use "next" marking information
1342 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
1343 //
1344 // NOTE: Only the "prev" marking information is guaranteed to be
1345 // consistent most of the time, so most calls to this should use
1346 // vo == UsePrevMarking.
1347 // Currently, there is only one case where this is called with
1348 // vo == UseNextMarking, which is to verify the "next" marking
1349 // information at the end of remark.
1350 // Currently there is only one place where this is called with
1351 // vo == UseFullMarking, which is to verify the marking during a
1352 // full GC.
1353 void verify(VerifyOption vo);
1354
1355 // WhiteBox testing support.
1356 virtual bool supports_concurrent_phase_control() const;
1357 virtual const char* const* concurrent_phases() const;
1358 virtual bool request_concurrent_phase(const char* phase);
1359
1360 // The methods below are here for convenience and dispatch the
1361 // appropriate method depending on value of the given VerifyOption
1362 // parameter. The values for that parameter, and their meanings,
1363 // are the same as those above.
1364
1365 bool is_obj_dead_cond(const oop obj,
1366 const HeapRegion* hr,
1367 const VerifyOption vo) const;
1368
1369 bool is_obj_dead_cond(const oop obj,
1370 const VerifyOption vo) const;
1371
1372 G1HeapSummary create_g1_heap_summary();
1373 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats);
1374
1375 // Printing
1376 private:
1377 void print_heap_regions() const;
1378 void print_regions_on(outputStream* st) const;
1379
1380 public:
1381 virtual void print_on(outputStream* st) const;
1382 virtual void print_extended_on(outputStream* st) const;
1383 virtual void print_on_error(outputStream* st) const;
1384
1385 virtual void print_gc_threads_on(outputStream* st) const;
1386 virtual void gc_threads_do(ThreadClosure* tc) const;
1387
1388 // Override
1389 void print_tracing_info() const;
1390
1391 // The following two methods are helpful for debugging RSet issues.
1392 void print_cset_rsets() PRODUCT_RETURN;
1393 void print_all_rsets() PRODUCT_RETURN;
1394
1395 public:
1396 size_t pending_card_num();
1397
1398 private:
1399 size_t _max_heap_capacity;
1400 };
1401
1402 class G1ParEvacuateFollowersClosure : public VoidClosure {
1403 private:
1404 double _start_term;
1405 double _term_time;
1406 size_t _term_attempts;
1407
1408 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); }
1409 void end_term_time() { _term_time += os::elapsedTime() - _start_term; }
1410 protected:
1411 G1CollectedHeap* _g1h;
1412 G1ParScanThreadState* _par_scan_state;
1413 RefToScanQueueSet* _queues;
1414 ParallelTaskTerminator* _terminator;
1415
1416 G1ParScanThreadState* par_scan_state() { return _par_scan_state; }
1417 RefToScanQueueSet* queues() { return _queues; }
1418 ParallelTaskTerminator* terminator() { return _terminator; }
1419
1420 public:
1421 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h,
1422 G1ParScanThreadState* par_scan_state,
1423 RefToScanQueueSet* queues,
1424 ParallelTaskTerminator* terminator)
1425 : _g1h(g1h), _par_scan_state(par_scan_state),
1426 _queues(queues), _terminator(terminator),
1427 _start_term(0.0), _term_time(0.0), _term_attempts(0) {}
1428
1429 void do_void();
1430
1431 double term_time() const { return _term_time; }
1432 size_t term_attempts() const { return _term_attempts; }
1433
1434 private:
1435 inline bool offer_termination();
1436 };
1437
1438 #endif // SHARE_VM_GC_G1_G1COLLECTEDHEAP_HPP