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 "utilities/stack.hpp"
55
56 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
57 // It uses the "Garbage First" heap organization and algorithm, which
58 // may combine concurrent marking with parallel, incremental compaction of
59 // heap subsets that will yield large amounts of garbage.
60
61 // Forward declarations
62 class HeapRegion;
63 class GenerationSpec;
64 class G1ParScanThreadState;
65 class G1ParScanThreadStateSet;
66 class G1ParScanThreadState;
67 class MemoryPool;
68 class MemoryManager;
69 class ObjectClosure;
70 class SpaceClosure;
71 class CompactibleSpaceClosure;
72 class Space;
73 class G1CollectionSet;
74 class G1CollectorPolicy;
75 class G1Policy;
76 class G1HotCardCache;
77 class G1RemSet;
78 class G1YoungRemSetSamplingThread;
79 class HeapRegionRemSetIterator;
80 class G1ConcurrentMark;
81 class G1ConcurrentMarkThread;
82 class G1ConcurrentRefine;
83 class GenerationCounters;
84 class STWGCTimer;
85 class G1NewTracer;
86 class EvacuationFailedInfo;
87 class nmethod;
88 class WorkGang;
89 class G1Allocator;
90 class G1ArchiveAllocator;
91 class G1FullGCScope;
92 class G1HeapVerifier;
93 class G1HeapSizingPolicy;
94 class G1HeapSummary;
95 class G1EvacSummary;
96
97 typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue;
98 typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet;
99
100 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() )
101 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
102
103 // The G1 STW is alive closure.
104 // An instance is embedded into the G1CH and used as the
105 // (optional) _is_alive_non_header closure in the STW
106 // reference processor. It is also extensively used during
107 // reference processing during STW evacuation pauses.
108 class G1STWIsAliveClosure : public BoolObjectClosure {
109 G1CollectedHeap* _g1h;
110 public:
111 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
112 bool do_object_b(oop p);
113 };
114
115 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure {
116 G1CollectedHeap* _g1h;
117 public:
118 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {}
119 bool do_object_b(oop p);
120 };
121
122 class G1RegionMappingChangedListener : public G1MappingChangedListener {
123 private:
124 void reset_from_card_cache(uint start_idx, size_t num_regions);
125 public:
126 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
127 };
128
129 class G1CollectedHeap : public CollectedHeap {
130 friend class G1FreeCollectionSetTask;
131 friend class VM_CollectForMetadataAllocation;
132 friend class VM_G1CollectForAllocation;
133 friend class VM_G1CollectFull;
134 friend class VMStructs;
135 friend class MutatorAllocRegion;
136 friend class G1FullCollector;
137 friend class G1GCAllocRegion;
138 friend class G1HeapVerifier;
139
140 // Closures used in implementation.
141 friend class G1ParScanThreadState;
142 friend class G1ParScanThreadStateSet;
143 friend class G1ParTask;
144 friend class G1PLABAllocator;
145 friend class G1PrepareCompactClosure;
146
147 // Other related classes.
148 friend class HeapRegionClaimer;
149
150 // Testing classes.
151 friend class G1CheckCSetFastTableClosure;
152
153 private:
154 G1YoungRemSetSamplingThread* _young_gen_sampling_thread;
155
156 WorkGang* _workers;
157 G1CollectorPolicy* _collector_policy;
158 G1CardTable* _card_table;
159
160 SoftRefPolicy _soft_ref_policy;
161
162 static size_t _humongous_object_threshold_in_words;
163
164 // These sets keep track of old, archive and humongous regions respectively.
165 HeapRegionSet _old_set;
166 HeapRegionSet _archive_set;
167 HeapRegionSet _humongous_set;
168
169 void eagerly_reclaim_humongous_regions();
170 // Start a new incremental collection set for the next pause.
171 void start_new_collection_set();
172
173 // The block offset table for the G1 heap.
174 G1BlockOffsetTable* _bot;
175
176 // Tears down the region sets / lists so that they are empty and the
177 // regions on the heap do not belong to a region set / list. The
178 // only exception is the humongous set which we leave unaltered. If
179 // free_list_only is true, it will only tear down the master free
180 // list. It is called before a Full GC (free_list_only == false) or
181 // before heap shrinking (free_list_only == true).
182 void tear_down_region_sets(bool free_list_only);
183
184 // Rebuilds the region sets / lists so that they are repopulated to
185 // reflect the contents of the heap. The only exception is the
186 // humongous set which was not torn down in the first place. If
187 // free_list_only is true, it will only rebuild the master free
188 // list. It is called after a Full GC (free_list_only == false) or
189 // after heap shrinking (free_list_only == true).
190 void rebuild_region_sets(bool free_list_only);
191
192 // Callback for region mapping changed events.
193 G1RegionMappingChangedListener _listener;
194
195 // The sequence of all heap regions in the heap.
196 HeapRegionManager _hrm;
197
198 // Manages all allocations with regions except humongous object allocations.
199 G1Allocator* _allocator;
200
201 // Manages all heap verification.
202 G1HeapVerifier* _verifier;
203
204 // Outside of GC pauses, the number of bytes used in all regions other
205 // than the current allocation region(s).
206 size_t _summary_bytes_used;
207
208 void increase_used(size_t bytes);
209 void decrease_used(size_t bytes);
210
211 void set_used(size_t bytes);
212
213 // Class that handles archive allocation ranges.
214 G1ArchiveAllocator* _archive_allocator;
215
216 // GC allocation statistics policy for survivors.
217 G1EvacStats _survivor_evac_stats;
218
219 // GC allocation statistics policy for tenured objects.
220 G1EvacStats _old_evac_stats;
221
222 // It specifies whether we should attempt to expand the heap after a
223 // region allocation failure. If heap expansion fails we set this to
224 // false so that we don't re-attempt the heap expansion (it's likely
225 // that subsequent expansion attempts will also fail if one fails).
226 // Currently, it is only consulted during GC and it's reset at the
227 // start of each GC.
228 bool _expand_heap_after_alloc_failure;
229
230 // Helper for monitoring and management support.
231 G1MonitoringSupport* _g1mm;
232
233 // Records whether the region at the given index is (still) a
234 // candidate for eager reclaim. Only valid for humongous start
235 // regions; other regions have unspecified values. Humongous start
236 // regions are initialized at start of collection pause, with
237 // candidates removed from the set as they are found reachable from
238 // roots or the young generation.
239 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> {
240 protected:
241 bool default_value() const { return false; }
242 public:
243 void clear() { G1BiasedMappedArray<bool>::clear(); }
244 void set_candidate(uint region, bool value) {
245 set_by_index(region, value);
246 }
247 bool is_candidate(uint region) {
248 return get_by_index(region);
249 }
250 };
251
252 HumongousReclaimCandidates _humongous_reclaim_candidates;
253 // Stores whether during humongous object registration we found candidate regions.
254 // If not, we can skip a few steps.
255 bool _has_humongous_reclaim_candidates;
256
257 G1HRPrinter _hr_printer;
258
259 // It decides whether an explicit GC should start a concurrent cycle
260 // instead of doing a STW GC. Currently, a concurrent cycle is
261 // explicitly started if:
262 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or
263 // (b) cause == _g1_humongous_allocation
264 // (c) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent.
265 // (d) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent.
266 // (e) cause == _wb_conc_mark
267 bool should_do_concurrent_full_gc(GCCause::Cause cause);
268
269 // indicates whether we are in young or mixed GC mode
270 G1CollectorState _collector_state;
271
272 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
273 // concurrent cycles) we have started.
274 volatile uint _old_marking_cycles_started;
275
276 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
277 // concurrent cycles) we have completed.
278 volatile uint _old_marking_cycles_completed;
279
280 // This is a non-product method that is helpful for testing. It is
281 // called at the end of a GC and artificially expands the heap by
282 // allocating a number of dead regions. This way we can induce very
283 // frequent marking cycles and stress the cleanup / concurrent
284 // cleanup code more (as all the regions that will be allocated by
285 // this method will be found dead by the marking cycle).
286 void allocate_dummy_regions() PRODUCT_RETURN;
287
288 // If the HR printer is active, dump the state of the regions in the
289 // heap after a compaction.
290 void print_hrm_post_compaction();
291
292 // Create a memory mapper for auxiliary data structures of the given size and
293 // translation factor.
294 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description,
295 size_t size,
296 size_t translation_factor);
297
298 void trace_heap(GCWhen::Type when, const GCTracer* tracer);
299
300 // These are macros so that, if the assert fires, we get the correct
301 // line number, file, etc.
302
303 #define heap_locking_asserts_params(_extra_message_) \
304 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
305 (_extra_message_), \
306 BOOL_TO_STR(Heap_lock->owned_by_self()), \
307 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
308 BOOL_TO_STR(Thread::current()->is_VM_thread())
309
310 #define assert_heap_locked() \
311 do { \
312 assert(Heap_lock->owned_by_self(), \
313 heap_locking_asserts_params("should be holding the Heap_lock")); \
314 } while (0)
315
316 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
317 do { \
318 assert(Heap_lock->owned_by_self() || \
319 (SafepointSynchronize::is_at_safepoint() && \
320 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
321 heap_locking_asserts_params("should be holding the Heap_lock or " \
322 "should be at a safepoint")); \
323 } while (0)
324
325 #define assert_heap_locked_and_not_at_safepoint() \
326 do { \
327 assert(Heap_lock->owned_by_self() && \
328 !SafepointSynchronize::is_at_safepoint(), \
329 heap_locking_asserts_params("should be holding the Heap_lock and " \
330 "should not be at a safepoint")); \
331 } while (0)
332
333 #define assert_heap_not_locked() \
334 do { \
335 assert(!Heap_lock->owned_by_self(), \
336 heap_locking_asserts_params("should not be holding the Heap_lock")); \
337 } while (0)
338
339 #define assert_heap_not_locked_and_not_at_safepoint() \
340 do { \
341 assert(!Heap_lock->owned_by_self() && \
342 !SafepointSynchronize::is_at_safepoint(), \
343 heap_locking_asserts_params("should not be holding the Heap_lock and " \
344 "should not be at a safepoint")); \
345 } while (0)
346
347 #define assert_at_safepoint_on_vm_thread() \
348 do { \
349 assert_at_safepoint(); \
350 assert(Thread::current_or_null() != NULL, "no current thread"); \
351 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \
352 } while (0)
353
354 // The young region list.
355 G1EdenRegions _eden;
356 G1SurvivorRegions _survivor;
357
358 STWGCTimer* _gc_timer_stw;
359
360 G1NewTracer* _gc_tracer_stw;
361
362 // The current policy object for the collector.
363 G1Policy* _g1_policy;
364 G1HeapSizingPolicy* _heap_sizing_policy;
365
366 G1CollectionSet _collection_set;
367
368 // Try to allocate a single non-humongous HeapRegion sufficient for
369 // an allocation of the given word_size. If do_expand is true,
370 // attempt to expand the heap if necessary to satisfy the allocation
371 // request. If the region is to be used as an old region or for a
372 // humongous object, set is_old to true. If not, to false.
373 HeapRegion* new_region(size_t word_size, bool is_old, bool do_expand);
374
375 // Initialize a contiguous set of free regions of length num_regions
376 // and starting at index first so that they appear as a single
377 // humongous region.
378 HeapWord* humongous_obj_allocate_initialize_regions(uint first,
379 uint num_regions,
380 size_t word_size);
381
382 // Attempt to allocate a humongous object of the given size. Return
383 // NULL if unsuccessful.
384 HeapWord* humongous_obj_allocate(size_t word_size);
385
386 // The following two methods, allocate_new_tlab() and
387 // mem_allocate(), are the two main entry points from the runtime
388 // into the G1's allocation routines. They have the following
389 // assumptions:
390 //
391 // * They should both be called outside safepoints.
392 //
393 // * They should both be called without holding the Heap_lock.
394 //
395 // * All allocation requests for new TLABs should go to
396 // allocate_new_tlab().
397 //
398 // * All non-TLAB allocation requests should go to mem_allocate().
399 //
400 // * If either call cannot satisfy the allocation request using the
401 // current allocating region, they will try to get a new one. If
402 // this fails, they will attempt to do an evacuation pause and
403 // retry the allocation.
404 //
405 // * If all allocation attempts fail, even after trying to schedule
406 // an evacuation pause, allocate_new_tlab() will return NULL,
407 // whereas mem_allocate() will attempt a heap expansion and/or
408 // schedule a Full GC.
409 //
410 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
411 // should never be called with word_size being humongous. All
412 // humongous allocation requests should go to mem_allocate() which
413 // will satisfy them with a special path.
414
415 virtual HeapWord* allocate_new_tlab(size_t min_size,
416 size_t requested_size,
417 size_t* actual_size);
418
419 virtual HeapWord* mem_allocate(size_t word_size,
420 bool* gc_overhead_limit_was_exceeded);
421
422 // First-level mutator allocation attempt: try to allocate out of
423 // the mutator alloc region without taking the Heap_lock. This
424 // should only be used for non-humongous allocations.
425 inline HeapWord* attempt_allocation(size_t min_word_size,
426 size_t desired_word_size,
427 size_t* actual_word_size);
428
429 // Second-level mutator allocation attempt: take the Heap_lock and
430 // retry the allocation attempt, potentially scheduling a GC
431 // pause. This should only be used for non-humongous allocations.
432 HeapWord* attempt_allocation_slow(size_t word_size);
433
434 // Takes the Heap_lock and attempts a humongous allocation. It can
435 // potentially schedule a GC pause.
436 HeapWord* attempt_allocation_humongous(size_t word_size);
437
438 // Allocation attempt that should be called during safepoints (e.g.,
439 // at the end of a successful GC). expect_null_mutator_alloc_region
440 // specifies whether the mutator alloc region is expected to be NULL
441 // or not.
442 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
443 bool expect_null_mutator_alloc_region);
444
445 // These methods are the "callbacks" from the G1AllocRegion class.
446
447 // For mutator alloc regions.
448 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force);
449 void retire_mutator_alloc_region(HeapRegion* alloc_region,
450 size_t allocated_bytes);
451
452 // For GC alloc regions.
453 bool has_more_regions(InCSetState dest);
454 HeapRegion* new_gc_alloc_region(size_t word_size, InCSetState dest);
455 void retire_gc_alloc_region(HeapRegion* alloc_region,
456 size_t allocated_bytes, InCSetState dest);
457
458 // - if explicit_gc is true, the GC is for a System.gc() etc,
459 // otherwise it's for a failed allocation.
460 // - if clear_all_soft_refs is true, all soft references should be
461 // cleared during the GC.
462 // - it returns false if it is unable to do the collection due to the
463 // GC locker being active, true otherwise.
464 bool do_full_collection(bool explicit_gc,
465 bool clear_all_soft_refs);
466
467 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
468 virtual void do_full_collection(bool clear_all_soft_refs);
469
470 // Callback from VM_G1CollectForAllocation operation.
471 // This function does everything necessary/possible to satisfy a
472 // failed allocation request (including collection, expansion, etc.)
473 HeapWord* satisfy_failed_allocation(size_t word_size,
474 bool* succeeded);
475 // Internal helpers used during full GC to split it up to
476 // increase readability.
477 void abort_concurrent_cycle();
478 void verify_before_full_collection(bool explicit_gc);
479 void prepare_heap_for_full_collection();
480 void prepare_heap_for_mutators();
481 void abort_refinement();
482 void verify_after_full_collection();
483 void print_heap_after_full_collection(G1HeapTransition* heap_transition);
484
485 // Helper method for satisfy_failed_allocation()
486 HeapWord* satisfy_failed_allocation_helper(size_t word_size,
487 bool do_gc,
488 bool clear_all_soft_refs,
489 bool expect_null_mutator_alloc_region,
490 bool* gc_succeeded);
491
492 // Attempting to expand the heap sufficiently
493 // to support an allocation of the given "word_size". If
494 // successful, perform the allocation and return the address of the
495 // allocated block, or else "NULL".
496 HeapWord* expand_and_allocate(size_t word_size);
497
498 // Process any reference objects discovered.
499 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states);
500
501 // If during an initial mark pause we may install a pending list head which is not
502 // otherwise reachable ensure that it is marked in the bitmap for concurrent marking
503 // to discover.
504 void make_pending_list_reachable();
505
506 // Merges the information gathered on a per-thread basis for all worker threads
507 // during GC into global variables.
508 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states);
509 public:
510 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; }
511
512 WorkGang* workers() const { return _workers; }
513
514 G1Allocator* allocator() {
515 return _allocator;
516 }
517
518 G1HeapVerifier* verifier() {
519 return _verifier;
520 }
521
522 G1MonitoringSupport* g1mm() {
523 assert(_g1mm != NULL, "should have been initialized");
524 return _g1mm;
525 }
526
527 void resize_heap_if_necessary();
528
529 // Expand the garbage-first heap by at least the given size (in bytes!).
530 // Returns true if the heap was expanded by the requested amount;
531 // false otherwise.
532 // (Rounds up to a HeapRegion boundary.)
533 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL);
534
535 // Returns the PLAB statistics for a given destination.
536 inline G1EvacStats* alloc_buffer_stats(InCSetState dest);
537
538 // Determines PLAB size for a given destination.
539 inline size_t desired_plab_sz(InCSetState dest);
540
541 // Do anything common to GC's.
542 void gc_prologue(bool full);
543 void gc_epilogue(bool full);
544
545 // Does the given region fulfill remembered set based eager reclaim candidate requirements?
546 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const;
547
548 // Modify the reclaim candidate set and test for presence.
549 // These are only valid for starts_humongous regions.
550 inline void set_humongous_reclaim_candidate(uint region, bool value);
551 inline bool is_humongous_reclaim_candidate(uint region);
552
553 // Remove from the reclaim candidate set. Also remove from the
554 // collection set so that later encounters avoid the slow path.
555 inline void set_humongous_is_live(oop obj);
556
557 // Register the given region to be part of the collection set.
558 inline void register_humongous_region_with_cset(uint index);
559 // Register regions with humongous objects (actually on the start region) in
560 // the in_cset_fast_test table.
561 void register_humongous_regions_with_cset();
562 // We register a region with the fast "in collection set" test. We
563 // simply set to true the array slot corresponding to this region.
564 void register_young_region_with_cset(HeapRegion* r) {
565 _in_cset_fast_test.set_in_young(r->hrm_index());
566 }
567 void register_old_region_with_cset(HeapRegion* r) {
568 _in_cset_fast_test.set_in_old(r->hrm_index());
569 }
570 void clear_in_cset(const HeapRegion* hr) {
571 _in_cset_fast_test.clear(hr);
572 }
573
574 void clear_cset_fast_test() {
575 _in_cset_fast_test.clear();
576 }
577
578 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause);
579
580 // This is called at the start of either a concurrent cycle or a Full
581 // GC to update the number of old marking cycles started.
582 void increment_old_marking_cycles_started();
583
584 // This is called at the end of either a concurrent cycle or a Full
585 // GC to update the number of old marking cycles completed. Those two
586 // can happen in a nested fashion, i.e., we start a concurrent
587 // cycle, a Full GC happens half-way through it which ends first,
588 // and then the cycle notices that a Full GC happened and ends
589 // too. The concurrent parameter is a boolean to help us do a bit
590 // tighter consistency checking in the method. If concurrent is
591 // false, the caller is the inner caller in the nesting (i.e., the
592 // Full GC). If concurrent is true, the caller is the outer caller
593 // in this nesting (i.e., the concurrent cycle). Further nesting is
594 // not currently supported. The end of this call also notifies
595 // the FullGCCount_lock in case a Java thread is waiting for a full
596 // GC to happen (e.g., it called System.gc() with
597 // +ExplicitGCInvokesConcurrent).
598 void increment_old_marking_cycles_completed(bool concurrent);
599
600 uint old_marking_cycles_completed() {
601 return _old_marking_cycles_completed;
602 }
603
604 G1HRPrinter* hr_printer() { return &_hr_printer; }
605
606 // Allocates a new heap region instance.
607 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr);
608
609 // Allocate the highest free region in the reserved heap. This will commit
610 // regions as necessary.
611 HeapRegion* alloc_highest_free_region();
612
613 // Frees a non-humongous region by initializing its contents and
614 // adding it to the free list that's passed as a parameter (this is
615 // usually a local list which will be appended to the master free
616 // list later). The used bytes of freed regions are accumulated in
617 // pre_used. If skip_remset is true, the region's RSet will not be freed
618 // up. If skip_hot_card_cache is true, the region's hot card cache will not
619 // be freed up. The assumption is that this will be done later.
620 // The locked parameter indicates if the caller has already taken
621 // care of proper synchronization. This may allow some optimizations.
622 void free_region(HeapRegion* hr,
623 FreeRegionList* free_list,
624 bool skip_remset,
625 bool skip_hot_card_cache = false,
626 bool locked = false);
627
628 // It dirties the cards that cover the block so that the post
629 // write barrier never queues anything when updating objects on this
630 // block. It is assumed (and in fact we assert) that the block
631 // belongs to a young region.
632 inline void dirty_young_block(HeapWord* start, size_t word_size);
633
634 // Frees a humongous region by collapsing it into individual regions
635 // and calling free_region() for each of them. The freed regions
636 // will be added to the free list that's passed as a parameter (this
637 // is usually a local list which will be appended to the master free
638 // list later).
639 // The method assumes that only a single thread is ever calling
640 // this for a particular region at once.
641 void free_humongous_region(HeapRegion* hr,
642 FreeRegionList* free_list);
643
644 // Facility for allocating in 'archive' regions in high heap memory and
645 // recording the allocated ranges. These should all be called from the
646 // VM thread at safepoints, without the heap lock held. They can be used
647 // to create and archive a set of heap regions which can be mapped at the
648 // same fixed addresses in a subsequent JVM invocation.
649 void begin_archive_alloc_range(bool open = false);
650
651 // Check if the requested size would be too large for an archive allocation.
652 bool is_archive_alloc_too_large(size_t word_size);
653
654 // Allocate memory of the requested size from the archive region. This will
655 // return NULL if the size is too large or if no memory is available. It
656 // does not trigger a garbage collection.
657 HeapWord* archive_mem_allocate(size_t word_size);
658
659 // Optionally aligns the end address and returns the allocated ranges in
660 // an array of MemRegions in order of ascending addresses.
661 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges,
662 size_t end_alignment_in_bytes = 0);
663
664 // Facility for allocating a fixed range within the heap and marking
665 // the containing regions as 'archive'. For use at JVM init time, when the
666 // caller may mmap archived heap data at the specified range(s).
667 // Verify that the MemRegions specified in the argument array are within the
668 // reserved heap.
669 bool check_archive_addresses(MemRegion* range, size_t count);
670
671 // Commit the appropriate G1 regions containing the specified MemRegions
672 // and mark them as 'archive' regions. The regions in the array must be
673 // non-overlapping and in order of ascending address.
674 bool alloc_archive_regions(MemRegion* range, size_t count, bool open);
675
676 // Insert any required filler objects in the G1 regions around the specified
677 // ranges to make the regions parseable. This must be called after
678 // alloc_archive_regions, and after class loading has occurred.
679 void fill_archive_regions(MemRegion* range, size_t count);
680
681 // For each of the specified MemRegions, uncommit the containing G1 regions
682 // which had been allocated by alloc_archive_regions. This should be called
683 // rather than fill_archive_regions at JVM init time if the archive file
684 // mapping failed, with the same non-overlapping and sorted MemRegion array.
685 void dealloc_archive_regions(MemRegion* range, size_t count);
686
687 oop materialize_archived_object(oop obj);
688
689 private:
690
691 // Shrink the garbage-first heap by at most the given size (in bytes!).
692 // (Rounds down to a HeapRegion boundary.)
693 void shrink(size_t expand_bytes);
694 void shrink_helper(size_t expand_bytes);
695
696 #if TASKQUEUE_STATS
697 static void print_taskqueue_stats_hdr(outputStream* const st);
698 void print_taskqueue_stats() const;
699 void reset_taskqueue_stats();
700 #endif // TASKQUEUE_STATS
701
702 // Schedule the VM operation that will do an evacuation pause to
703 // satisfy an allocation request of word_size. *succeeded will
704 // return whether the VM operation was successful (it did do an
705 // evacuation pause) or not (another thread beat us to it or the GC
706 // locker was active). Given that we should not be holding the
707 // Heap_lock when we enter this method, we will pass the
708 // gc_count_before (i.e., total_collections()) as a parameter since
709 // it has to be read while holding the Heap_lock. Currently, both
710 // methods that call do_collection_pause() release the Heap_lock
711 // before the call, so it's easy to read gc_count_before just before.
712 HeapWord* do_collection_pause(size_t word_size,
713 uint gc_count_before,
714 bool* succeeded,
715 GCCause::Cause gc_cause);
716
717 void wait_for_root_region_scanning();
718
719 // The guts of the incremental collection pause, executed by the vm
720 // thread. It returns false if it is unable to do the collection due
721 // to the GC locker being active, true otherwise
722 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
723
724 // Actually do the work of evacuating the collection set.
725 void evacuate_collection_set(G1ParScanThreadStateSet* per_thread_states);
726
727 void pre_evacuate_collection_set();
728 void post_evacuate_collection_set(EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss);
729
730 // Print the header for the per-thread termination statistics.
731 static void print_termination_stats_hdr();
732 // Print actual per-thread termination statistics.
733 void print_termination_stats(uint worker_id,
734 double elapsed_ms,
735 double strong_roots_ms,
736 double term_ms,
737 size_t term_attempts,
738 size_t alloc_buffer_waste,
739 size_t undo_waste) const;
740 // Update object copying statistics.
741 void record_obj_copy_mem_stats();
742
743 // The hot card cache for remembered set insertion optimization.
744 G1HotCardCache* _hot_card_cache;
745
746 // The g1 remembered set of the heap.
747 G1RemSet* _g1_rem_set;
748
749 // A set of cards that cover the objects for which the Rsets should be updated
750 // concurrently after the collection.
751 DirtyCardQueueSet _dirty_card_queue_set;
752
753 // After a collection pause, convert the regions in the collection set into free
754 // regions.
755 void free_collection_set(G1CollectionSet* collection_set, EvacuationInfo& evacuation_info, const size_t* surviving_young_words);
756
757 // Abandon the current collection set without recording policy
758 // statistics or updating free lists.
759 void abandon_collection_set(G1CollectionSet* collection_set);
760
761 // The concurrent marker (and the thread it runs in.)
762 G1ConcurrentMark* _cm;
763 G1ConcurrentMarkThread* _cm_thread;
764
765 // The concurrent refiner.
766 G1ConcurrentRefine* _cr;
767
768 // The parallel task queues
769 RefToScanQueueSet *_task_queues;
770
771 // True iff a evacuation has failed in the current collection.
772 bool _evacuation_failed;
773
774 EvacuationFailedInfo* _evacuation_failed_info_array;
775
776 // Failed evacuations cause some logical from-space objects to have
777 // forwarding pointers to themselves. Reset them.
778 void remove_self_forwarding_pointers();
779
780 // Restore the objects in the regions in the collection set after an
781 // evacuation failure.
782 void restore_after_evac_failure();
783
784 PreservedMarksSet _preserved_marks_set;
785
786 // Preserve the mark of "obj", if necessary, in preparation for its mark
787 // word being overwritten with a self-forwarding-pointer.
788 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markOop m);
789
790 #ifndef PRODUCT
791 // Support for forcing evacuation failures. Analogous to
792 // PromotionFailureALot for the other collectors.
793
794 // Records whether G1EvacuationFailureALot should be in effect
795 // for the current GC
796 bool _evacuation_failure_alot_for_current_gc;
797
798 // Used to record the GC number for interval checking when
799 // determining whether G1EvaucationFailureALot is in effect
800 // for the current GC.
801 size_t _evacuation_failure_alot_gc_number;
802
803 // Count of the number of evacuations between failures.
804 volatile size_t _evacuation_failure_alot_count;
805
806 // Set whether G1EvacuationFailureALot should be in effect
807 // for the current GC (based upon the type of GC and which
808 // command line flags are set);
809 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc,
810 bool during_initial_mark,
811 bool mark_or_rebuild_in_progress);
812
813 inline void set_evacuation_failure_alot_for_current_gc();
814
815 // Return true if it's time to cause an evacuation failure.
816 inline bool evacuation_should_fail();
817
818 // Reset the G1EvacuationFailureALot counters. Should be called at
819 // the end of an evacuation pause in which an evacuation failure occurred.
820 inline void reset_evacuation_should_fail();
821 #endif // !PRODUCT
822
823 // ("Weak") Reference processing support.
824 //
825 // G1 has 2 instances of the reference processor class. One
826 // (_ref_processor_cm) handles reference object discovery
827 // and subsequent processing during concurrent marking cycles.
828 //
829 // The other (_ref_processor_stw) handles reference object
830 // discovery and processing during full GCs and incremental
831 // evacuation pauses.
832 //
833 // During an incremental pause, reference discovery will be
834 // temporarily disabled for _ref_processor_cm and will be
835 // enabled for _ref_processor_stw. At the end of the evacuation
836 // pause references discovered by _ref_processor_stw will be
837 // processed and discovery will be disabled. The previous
838 // setting for reference object discovery for _ref_processor_cm
839 // will be re-instated.
840 //
841 // At the start of marking:
842 // * Discovery by the CM ref processor is verified to be inactive
843 // and it's discovered lists are empty.
844 // * Discovery by the CM ref processor is then enabled.
845 //
846 // At the end of marking:
847 // * Any references on the CM ref processor's discovered
848 // lists are processed (possibly MT).
849 //
850 // At the start of full GC we:
851 // * Disable discovery by the CM ref processor and
852 // empty CM ref processor's discovered lists
853 // (without processing any entries).
854 // * Verify that the STW ref processor is inactive and it's
855 // discovered lists are empty.
856 // * Temporarily set STW ref processor discovery as single threaded.
857 // * Temporarily clear the STW ref processor's _is_alive_non_header
858 // field.
859 // * Finally enable discovery by the STW ref processor.
860 //
861 // The STW ref processor is used to record any discovered
862 // references during the full GC.
863 //
864 // At the end of a full GC we:
865 // * Enqueue any reference objects discovered by the STW ref processor
866 // that have non-live referents. This has the side-effect of
867 // making the STW ref processor inactive by disabling discovery.
868 // * Verify that the CM ref processor is still inactive
869 // and no references have been placed on it's discovered
870 // lists (also checked as a precondition during initial marking).
871
872 // The (stw) reference processor...
873 ReferenceProcessor* _ref_processor_stw;
874
875 // During reference object discovery, the _is_alive_non_header
876 // closure (if non-null) is applied to the referent object to
877 // determine whether the referent is live. If so then the
878 // reference object does not need to be 'discovered' and can
879 // be treated as a regular oop. This has the benefit of reducing
880 // the number of 'discovered' reference objects that need to
881 // be processed.
882 //
883 // Instance of the is_alive closure for embedding into the
884 // STW reference processor as the _is_alive_non_header field.
885 // Supplying a value for the _is_alive_non_header field is
886 // optional but doing so prevents unnecessary additions to
887 // the discovered lists during reference discovery.
888 G1STWIsAliveClosure _is_alive_closure_stw;
889
890 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw;
891
892 // The (concurrent marking) reference processor...
893 ReferenceProcessor* _ref_processor_cm;
894
895 // Instance of the concurrent mark is_alive closure for embedding
896 // into the Concurrent Marking reference processor as the
897 // _is_alive_non_header field. Supplying a value for the
898 // _is_alive_non_header field is optional but doing so prevents
899 // unnecessary additions to the discovered lists during reference
900 // discovery.
901 G1CMIsAliveClosure _is_alive_closure_cm;
902
903 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm;
904 public:
905
906 RefToScanQueue *task_queue(uint i) const;
907
908 uint num_task_queues() const;
909
910 // A set of cards where updates happened during the GC
911 DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
912
913 // Create a G1CollectedHeap with the specified policy.
914 // Must call the initialize method afterwards.
915 // May not return if something goes wrong.
916 G1CollectedHeap(G1CollectorPolicy* policy);
917
918 private:
919 jint initialize_concurrent_refinement();
920 jint initialize_young_gen_sampling_thread();
921 public:
922 // Initialize the G1CollectedHeap to have the initial and
923 // maximum sizes and remembered and barrier sets
924 // specified by the policy object.
925 jint initialize();
926
927 virtual void stop();
928 virtual void safepoint_synchronize_begin();
929 virtual void safepoint_synchronize_end();
930
931 // Return the (conservative) maximum heap alignment for any G1 heap
932 static size_t conservative_max_heap_alignment();
933
934 // Does operations required after initialization has been done.
935 void post_initialize();
936
937 // Initialize weak reference processing.
938 void ref_processing_init();
939
940 virtual Name kind() const {
941 return CollectedHeap::G1;
942 }
943
944 virtual const char* name() const {
945 return "G1";
946 }
947
948 const G1CollectorState* collector_state() const { return &_collector_state; }
949 G1CollectorState* collector_state() { return &_collector_state; }
950
951 // The current policy object for the collector.
952 G1Policy* g1_policy() const { return _g1_policy; }
953
954 const G1CollectionSet* collection_set() const { return &_collection_set; }
955 G1CollectionSet* collection_set() { return &_collection_set; }
956
957 virtual CollectorPolicy* collector_policy() const;
958
959 virtual SoftRefPolicy* soft_ref_policy();
960
961 virtual void initialize_serviceability();
962 virtual MemoryUsage memory_usage();
963 virtual GrowableArray<GCMemoryManager*> memory_managers();
964 virtual GrowableArray<MemoryPool*> memory_pools();
965
966 // The rem set and barrier set.
967 G1RemSet* g1_rem_set() const { return _g1_rem_set; }
968
969 // Try to minimize the remembered set.
970 void scrub_rem_set();
971
972 // Apply the given closure on all cards in the Hot Card Cache, emptying it.
973 void iterate_hcc_closure(CardTableEntryClosure* cl, uint worker_i);
974
975 // Apply the given closure on all cards in the Dirty Card Queue Set, emptying it.
976 void iterate_dirty_card_closure(CardTableEntryClosure* cl, uint worker_i);
977
978 // The shared block offset table array.
979 G1BlockOffsetTable* bot() const { return _bot; }
980
981 // Reference Processing accessors
982
983 // The STW reference processor....
984 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
985
986 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; }
987
988 // The Concurrent Marking reference processor...
989 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
990
991 size_t unused_committed_regions_in_bytes() const;
992 virtual size_t capacity() const;
993 virtual size_t used() const;
994 // This should be called when we're not holding the heap lock. The
995 // result might be a bit inaccurate.
996 size_t used_unlocked() const;
997 size_t recalculate_used() const;
998
999 // These virtual functions do the actual allocation.
1000 // Some heaps may offer a contiguous region for shared non-blocking
1001 // allocation, via inlined code (by exporting the address of the top and
1002 // end fields defining the extent of the contiguous allocation region.)
1003 // But G1CollectedHeap doesn't yet support this.
1004
1005 virtual bool is_maximal_no_gc() const {
1006 return _hrm.available() == 0;
1007 }
1008
1009 // Returns whether there are any regions left in the heap for allocation.
1010 bool has_regions_left_for_allocation() const {
1011 return !is_maximal_no_gc() || num_free_regions() != 0;
1012 }
1013
1014 // The current number of regions in the heap.
1015 uint num_regions() const { return _hrm.length(); }
1016
1017 // The max number of regions in the heap.
1018 uint max_regions() const { return _hrm.max_length(); }
1019
1020 // The number of regions that are completely free.
1021 uint num_free_regions() const { return _hrm.num_free_regions(); }
1022
1023 MemoryUsage get_auxiliary_data_memory_usage() const {
1024 return _hrm.get_auxiliary_data_memory_usage();
1025 }
1026
1027 // The number of regions that are not completely free.
1028 uint num_used_regions() const { return num_regions() - num_free_regions(); }
1029
1030 #ifdef ASSERT
1031 bool is_on_master_free_list(HeapRegion* hr) {
1032 return _hrm.is_free(hr);
1033 }
1034 #endif // ASSERT
1035
1036 inline void old_set_add(HeapRegion* hr);
1037 inline void old_set_remove(HeapRegion* hr);
1038
1039 inline void archive_set_add(HeapRegion* hr);
1040
1041 size_t non_young_capacity_bytes() {
1042 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes;
1043 }
1044
1045 // Determine whether the given region is one that we are using as an
1046 // old GC alloc region.
1047 bool is_old_gc_alloc_region(HeapRegion* hr);
1048
1049 // Perform a collection of the heap; intended for use in implementing
1050 // "System.gc". This probably implies as full a collection as the
1051 // "CollectedHeap" supports.
1052 virtual void collect(GCCause::Cause cause);
1053
1054 // True iff an evacuation has failed in the most-recent collection.
1055 bool evacuation_failed() { return _evacuation_failed; }
1056
1057 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed);
1058 void prepend_to_freelist(FreeRegionList* list);
1059 void decrement_summary_bytes(size_t bytes);
1060
1061 virtual bool is_in(const void* p) const;
1062 #ifdef ASSERT
1063 // Returns whether p is in one of the available areas of the heap. Slow but
1064 // extensive version.
1065 bool is_in_exact(const void* p) const;
1066 #endif
1067
1068 // Return "TRUE" iff the given object address is within the collection
1069 // set. Assumes that the reference points into the heap.
1070 inline bool is_in_cset(const HeapRegion *hr);
1071 inline bool is_in_cset(oop obj);
1072 inline bool is_in_cset(HeapWord* addr);
1073
1074 inline bool is_in_cset_or_humongous(const oop obj);
1075
1076 private:
1077 // This array is used for a quick test on whether a reference points into
1078 // the collection set or not. Each of the array's elements denotes whether the
1079 // corresponding region is in the collection set or not.
1080 G1InCSetStateFastTestBiasedMappedArray _in_cset_fast_test;
1081
1082 public:
1083
1084 inline InCSetState in_cset_state(const oop obj);
1085
1086 // Return "TRUE" iff the given object address is in the reserved
1087 // region of g1.
1088 bool is_in_g1_reserved(const void* p) const {
1089 return _hrm.reserved().contains(p);
1090 }
1091
1092 // Returns a MemRegion that corresponds to the space that has been
1093 // reserved for the heap
1094 MemRegion g1_reserved() const {
1095 return _hrm.reserved();
1096 }
1097
1098 virtual bool is_in_closed_subset(const void* p) const;
1099
1100 G1HotCardCache* g1_hot_card_cache() const { return _hot_card_cache; }
1101
1102 G1CardTable* card_table() const {
1103 return _card_table;
1104 }
1105
1106 // Iteration functions.
1107
1108 // Iterate over all objects, calling "cl.do_object" on each.
1109 virtual void object_iterate(ObjectClosure* cl);
1110
1111 virtual void safe_object_iterate(ObjectClosure* cl) {
1112 object_iterate(cl);
1113 }
1114
1115 // Iterate over heap regions, in address order, terminating the
1116 // iteration early if the "do_heap_region" method returns "true".
1117 void heap_region_iterate(HeapRegionClosure* blk) const;
1118
1119 // Return the region with the given index. It assumes the index is valid.
1120 inline HeapRegion* region_at(uint index) const;
1121 inline HeapRegion* region_at_or_null(uint index) const;
1122
1123 // Return the next region (by index) that is part of the same
1124 // humongous object that hr is part of.
1125 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const;
1126
1127 // Calculate the region index of the given address. Given address must be
1128 // within the heap.
1129 inline uint addr_to_region(HeapWord* addr) const;
1130
1131 inline HeapWord* bottom_addr_for_region(uint index) const;
1132
1133 // Two functions to iterate over the heap regions in parallel. Threads
1134 // compete using the HeapRegionClaimer to claim the regions before
1135 // applying the closure on them.
1136 // The _from_worker_offset version uses the HeapRegionClaimer and
1137 // the worker id to calculate a start offset to prevent all workers to
1138 // start from the point.
1139 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl,
1140 HeapRegionClaimer* hrclaimer,
1141 uint worker_id) const;
1142
1143 void heap_region_par_iterate_from_start(HeapRegionClosure* cl,
1144 HeapRegionClaimer* hrclaimer) const;
1145
1146 // Iterate over the regions (if any) in the current collection set.
1147 void collection_set_iterate(HeapRegionClosure* blk);
1148
1149 // Iterate over the regions (if any) in the current collection set. Starts the
1150 // iteration over the entire collection set so that the start regions of a given
1151 // worker id over the set active_workers are evenly spread across the set of
1152 // collection set regions.
1153 void collection_set_iterate_from(HeapRegionClosure *blk, uint worker_id);
1154
1155 // Returns the HeapRegion that contains addr. addr must not be NULL.
1156 template <class T>
1157 inline HeapRegion* heap_region_containing(const T addr) const;
1158
1159 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted
1160 // region. addr must not be NULL.
1161 template <class T>
1162 inline HeapRegion* heap_region_containing_or_null(const T addr) const;
1163
1164 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1165 // each address in the (reserved) heap is a member of exactly
1166 // one block. The defining characteristic of a block is that it is
1167 // possible to find its size, and thus to progress forward to the next
1168 // block. (Blocks may be of different sizes.) Thus, blocks may
1169 // represent Java objects, or they might be free blocks in a
1170 // free-list-based heap (or subheap), as long as the two kinds are
1171 // distinguishable and the size of each is determinable.
1172
1173 // Returns the address of the start of the "block" that contains the
1174 // address "addr". We say "blocks" instead of "object" since some heaps
1175 // may not pack objects densely; a chunk may either be an object or a
1176 // non-object.
1177 virtual HeapWord* block_start(const void* addr) const;
1178
1179 // Requires "addr" to be the start of a chunk, and returns its size.
1180 // "addr + size" is required to be the start of a new chunk, or the end
1181 // of the active area of the heap.
1182 virtual size_t block_size(const HeapWord* addr) const;
1183
1184 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1185 // the block is an object.
1186 virtual bool block_is_obj(const HeapWord* addr) const;
1187
1188 // Section on thread-local allocation buffers (TLABs)
1189 // See CollectedHeap for semantics.
1190
1191 bool supports_tlab_allocation() const;
1192 size_t tlab_capacity(Thread* ignored) const;
1193 size_t tlab_used(Thread* ignored) const;
1194 size_t max_tlab_size() const;
1195 size_t unsafe_max_tlab_alloc(Thread* ignored) const;
1196
1197 inline bool is_in_young(const oop obj);
1198
1199 // Returns "true" iff the given word_size is "very large".
1200 static bool is_humongous(size_t word_size) {
1201 // Note this has to be strictly greater-than as the TLABs
1202 // are capped at the humongous threshold and we want to
1203 // ensure that we don't try to allocate a TLAB as
1204 // humongous and that we don't allocate a humongous
1205 // object in a TLAB.
1206 return word_size > _humongous_object_threshold_in_words;
1207 }
1208
1209 // Returns the humongous threshold for a specific region size
1210 static size_t humongous_threshold_for(size_t region_size) {
1211 return (region_size / 2);
1212 }
1213
1214 // Returns the number of regions the humongous object of the given word size
1215 // requires.
1216 static size_t humongous_obj_size_in_regions(size_t word_size);
1217
1218 // Print the maximum heap capacity.
1219 virtual size_t max_capacity() const;
1220
1221 virtual jlong millis_since_last_gc();
1222
1223
1224 // Convenience function to be used in situations where the heap type can be
1225 // asserted to be this type.
1226 static G1CollectedHeap* heap();
1227
1228 void set_region_short_lived_locked(HeapRegion* hr);
1229 // add appropriate methods for any other surv rate groups
1230
1231 const G1SurvivorRegions* survivor() const { return &_survivor; }
1232
1233 uint eden_regions_count() const { return _eden.length(); }
1234 uint survivor_regions_count() const { return _survivor.length(); }
1235 uint young_regions_count() const { return _eden.length() + _survivor.length(); }
1236 uint old_regions_count() const { return _old_set.length(); }
1237 uint archive_regions_count() const { return _archive_set.length(); }
1238 uint humongous_regions_count() const { return _humongous_set.length(); }
1239
1240 #ifdef ASSERT
1241 bool check_young_list_empty();
1242 #endif
1243
1244 // *** Stuff related to concurrent marking. It's not clear to me that so
1245 // many of these need to be public.
1246
1247 // The functions below are helper functions that a subclass of
1248 // "CollectedHeap" can use in the implementation of its virtual
1249 // functions.
1250 // This performs a concurrent marking of the live objects in a
1251 // bitmap off to the side.
1252 void do_concurrent_mark();
1253
1254 bool is_marked_next(oop obj) const;
1255
1256 // Determine if an object is dead, given the object and also
1257 // the region to which the object belongs. An object is dead
1258 // iff a) it was not allocated since the last mark, b) it
1259 // is not marked, and c) it is not in an archive region.
1260 bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
1261 return
1262 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) &&
1263 !hr->is_archive();
1264 }
1265
1266 // This function returns true when an object has been
1267 // around since the previous marking and hasn't yet
1268 // been marked during this marking, and is not in an archive region.
1269 bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
1270 return
1271 !hr->obj_allocated_since_next_marking(obj) &&
1272 !is_marked_next(obj) &&
1273 !hr->is_archive();
1274 }
1275
1276 // Determine if an object is dead, given only the object itself.
1277 // This will find the region to which the object belongs and
1278 // then call the region version of the same function.
1279
1280 // Added if it is NULL it isn't dead.
1281
1282 inline bool is_obj_dead(const oop obj) const;
1283
1284 inline bool is_obj_ill(const oop obj) const;
1285
1286 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const;
1287 inline bool is_obj_dead_full(const oop obj) const;
1288
1289 G1ConcurrentMark* concurrent_mark() const { return _cm; }
1290
1291 // Refinement
1292
1293 G1ConcurrentRefine* concurrent_refine() const { return _cr; }
1294
1295 // Optimized nmethod scanning support routines
1296
1297 // Is an oop scavengeable
1298 virtual bool is_scavengable(oop obj);
1299
1300 // Register the given nmethod with the G1 heap.
1301 virtual void register_nmethod(nmethod* nm);
1302
1303 // Unregister the given nmethod from the G1 heap.
1304 virtual void unregister_nmethod(nmethod* nm);
1305
1306 // Free up superfluous code root memory.
1307 void purge_code_root_memory();
1308
1309 // Rebuild the strong code root lists for each region
1310 // after a full GC.
1311 void rebuild_strong_code_roots();
1312
1313 // Partial cleaning used when class unloading is disabled.
1314 // Let the caller choose what structures to clean out:
1315 // - StringTable
1316 // - StringDeduplication structures
1317 void partial_cleaning(BoolObjectClosure* is_alive, bool unlink_strings, bool unlink_string_dedup);
1318
1319 // Complete cleaning used when class unloading is enabled.
1320 // Cleans out all structures handled by partial_cleaning and also the CodeCache.
1321 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred);
1322
1323 // Redirty logged cards in the refinement queue.
1324 void redirty_logged_cards();
1325 // Verification
1326
1327 // Deduplicate the string
1328 virtual void deduplicate_string(oop str);
1329
1330 // Perform any cleanup actions necessary before allowing a verification.
1331 virtual void prepare_for_verify();
1332
1333 // Perform verification.
1334
1335 // vo == UsePrevMarking -> use "prev" marking information,
1336 // vo == UseNextMarking -> use "next" marking information
1337 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
1338 //
1339 // NOTE: Only the "prev" marking information is guaranteed to be
1340 // consistent most of the time, so most calls to this should use
1341 // vo == UsePrevMarking.
1342 // Currently, there is only one case where this is called with
1343 // vo == UseNextMarking, which is to verify the "next" marking
1344 // information at the end of remark.
1345 // Currently there is only one place where this is called with
1346 // vo == UseFullMarking, which is to verify the marking during a
1347 // full GC.
1348 void verify(VerifyOption vo);
1349
1350 // WhiteBox testing support.
1351 virtual bool supports_concurrent_phase_control() const;
1352 virtual const char* const* concurrent_phases() const;
1353 virtual bool request_concurrent_phase(const char* phase);
1354
1355 virtual WorkGang* get_safepoint_workers() { return _workers; }
1356
1357 // The methods below are here for convenience and dispatch the
1358 // appropriate method depending on value of the given VerifyOption
1359 // parameter. The values for that parameter, and their meanings,
1360 // are the same as those above.
1361
1362 bool is_obj_dead_cond(const oop obj,
1363 const HeapRegion* hr,
1364 const VerifyOption vo) const;
1365
1366 bool is_obj_dead_cond(const oop obj,
1367 const VerifyOption vo) const;
1368
1369 G1HeapSummary create_g1_heap_summary();
1370 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats);
1371
1372 // Printing
1373 private:
1374 void print_heap_regions() const;
1375 void print_regions_on(outputStream* st) const;
1376
1377 public:
1378 virtual void print_on(outputStream* st) const;
1379 virtual void print_extended_on(outputStream* st) const;
1380 virtual void print_on_error(outputStream* st) const;
1381
1382 virtual void print_gc_threads_on(outputStream* st) const;
1383 virtual void gc_threads_do(ThreadClosure* tc) const;
1384
1385 // Override
1386 void print_tracing_info() const;
1387
1388 // The following two methods are helpful for debugging RSet issues.
1389 void print_cset_rsets() PRODUCT_RETURN;
1390 void print_all_rsets() PRODUCT_RETURN;
1391
1392 size_t pending_card_num();
1393 };
1394
1395 class G1ParEvacuateFollowersClosure : public VoidClosure {
1396 private:
1397 double _start_term;
1398 double _term_time;
1399 size_t _term_attempts;
1400
1401 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); }
1402 void end_term_time() { _term_time += os::elapsedTime() - _start_term; }
1403 protected:
1404 G1CollectedHeap* _g1h;
1405 G1ParScanThreadState* _par_scan_state;
1406 RefToScanQueueSet* _queues;
1407 ParallelTaskTerminator* _terminator;
1408
1409 G1ParScanThreadState* par_scan_state() { return _par_scan_state; }
1410 RefToScanQueueSet* queues() { return _queues; }
1411 ParallelTaskTerminator* terminator() { return _terminator; }
1412
1413 public:
1414 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h,
1415 G1ParScanThreadState* par_scan_state,
1416 RefToScanQueueSet* queues,
1417 ParallelTaskTerminator* terminator)
1418 : _start_term(0.0), _term_time(0.0), _term_attempts(0),
1419 _g1h(g1h), _par_scan_state(par_scan_state),
1420 _queues(queues), _terminator(terminator) {}
1421
1422 void do_void();
1423
1424 double term_time() const { return _term_time; }
1425 size_t term_attempts() const { return _term_attempts; }
1426
1427 private:
1428 inline bool offer_termination();
1429 };
1430
1431 #endif // SHARE_VM_GC_G1_G1COLLECTEDHEAP_HPP