Thu, 23 Aug 2012 10:21:12 +0200
7178363: G1: Remove the serial code for PrintGCDetails and make it a special case of the parallel code
Summary: Also reviewed by vitalyd@gmail.com. Introduced the WorkerDataArray class. Fixed some minor logging bugs.
Reviewed-by: johnc, mgerdin
1 /*
2 * Copyright (c) 2001, 2012, 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.
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP
28 #include "gc_implementation/g1/concurrentMark.hpp"
29 #include "gc_implementation/g1/g1AllocRegion.hpp"
30 #include "gc_implementation/g1/g1HRPrinter.hpp"
31 #include "gc_implementation/g1/g1RemSet.hpp"
32 #include "gc_implementation/g1/g1MonitoringSupport.hpp"
33 #include "gc_implementation/g1/heapRegionSeq.hpp"
34 #include "gc_implementation/g1/heapRegionSets.hpp"
35 #include "gc_implementation/shared/hSpaceCounters.hpp"
36 #include "gc_implementation/shared/parGCAllocBuffer.hpp"
37 #include "memory/barrierSet.hpp"
38 #include "memory/memRegion.hpp"
39 #include "memory/sharedHeap.hpp"
41 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
42 // It uses the "Garbage First" heap organization and algorithm, which
43 // may combine concurrent marking with parallel, incremental compaction of
44 // heap subsets that will yield large amounts of garbage.
46 class HeapRegion;
47 class HRRSCleanupTask;
48 class PermanentGenerationSpec;
49 class GenerationSpec;
50 class OopsInHeapRegionClosure;
51 class G1ScanHeapEvacClosure;
52 class ObjectClosure;
53 class SpaceClosure;
54 class CompactibleSpaceClosure;
55 class Space;
56 class G1CollectorPolicy;
57 class GenRemSet;
58 class G1RemSet;
59 class HeapRegionRemSetIterator;
60 class ConcurrentMark;
61 class ConcurrentMarkThread;
62 class ConcurrentG1Refine;
63 class GenerationCounters;
65 typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue;
66 typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet;
68 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() )
69 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion )
71 enum GCAllocPurpose {
72 GCAllocForTenured,
73 GCAllocForSurvived,
74 GCAllocPurposeCount
75 };
77 class YoungList : public CHeapObj<mtGC> {
78 private:
79 G1CollectedHeap* _g1h;
81 HeapRegion* _head;
83 HeapRegion* _survivor_head;
84 HeapRegion* _survivor_tail;
86 HeapRegion* _curr;
88 uint _length;
89 uint _survivor_length;
91 size_t _last_sampled_rs_lengths;
92 size_t _sampled_rs_lengths;
94 void empty_list(HeapRegion* list);
96 public:
97 YoungList(G1CollectedHeap* g1h);
99 void push_region(HeapRegion* hr);
100 void add_survivor_region(HeapRegion* hr);
102 void empty_list();
103 bool is_empty() { return _length == 0; }
104 uint length() { return _length; }
105 uint survivor_length() { return _survivor_length; }
107 // Currently we do not keep track of the used byte sum for the
108 // young list and the survivors and it'd be quite a lot of work to
109 // do so. When we'll eventually replace the young list with
110 // instances of HeapRegionLinkedList we'll get that for free. So,
111 // we'll report the more accurate information then.
112 size_t eden_used_bytes() {
113 assert(length() >= survivor_length(), "invariant");
114 return (size_t) (length() - survivor_length()) * HeapRegion::GrainBytes;
115 }
116 size_t survivor_used_bytes() {
117 return (size_t) survivor_length() * HeapRegion::GrainBytes;
118 }
120 void rs_length_sampling_init();
121 bool rs_length_sampling_more();
122 void rs_length_sampling_next();
124 void reset_sampled_info() {
125 _last_sampled_rs_lengths = 0;
126 }
127 size_t sampled_rs_lengths() { return _last_sampled_rs_lengths; }
129 // for development purposes
130 void reset_auxilary_lists();
131 void clear() { _head = NULL; _length = 0; }
133 void clear_survivors() {
134 _survivor_head = NULL;
135 _survivor_tail = NULL;
136 _survivor_length = 0;
137 }
139 HeapRegion* first_region() { return _head; }
140 HeapRegion* first_survivor_region() { return _survivor_head; }
141 HeapRegion* last_survivor_region() { return _survivor_tail; }
143 // debugging
144 bool check_list_well_formed();
145 bool check_list_empty(bool check_sample = true);
146 void print();
147 };
149 class MutatorAllocRegion : public G1AllocRegion {
150 protected:
151 virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
152 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
153 public:
154 MutatorAllocRegion()
155 : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { }
156 };
158 // The G1 STW is alive closure.
159 // An instance is embedded into the G1CH and used as the
160 // (optional) _is_alive_non_header closure in the STW
161 // reference processor. It is also extensively used during
162 // refence processing during STW evacuation pauses.
163 class G1STWIsAliveClosure: public BoolObjectClosure {
164 G1CollectedHeap* _g1;
165 public:
166 G1STWIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) {}
167 void do_object(oop p) { assert(false, "Do not call."); }
168 bool do_object_b(oop p);
169 };
171 class SurvivorGCAllocRegion : public G1AllocRegion {
172 protected:
173 virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
174 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
175 public:
176 SurvivorGCAllocRegion()
177 : G1AllocRegion("Survivor GC Alloc Region", false /* bot_updates */) { }
178 };
180 class OldGCAllocRegion : public G1AllocRegion {
181 protected:
182 virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
183 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
184 public:
185 OldGCAllocRegion()
186 : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { }
187 };
189 class RefineCardTableEntryClosure;
191 class G1CollectedHeap : public SharedHeap {
192 friend class VM_G1CollectForAllocation;
193 friend class VM_GenCollectForPermanentAllocation;
194 friend class VM_G1CollectFull;
195 friend class VM_G1IncCollectionPause;
196 friend class VMStructs;
197 friend class MutatorAllocRegion;
198 friend class SurvivorGCAllocRegion;
199 friend class OldGCAllocRegion;
201 // Closures used in implementation.
202 template <bool do_gen_barrier, G1Barrier barrier, bool do_mark_object>
203 friend class G1ParCopyClosure;
204 friend class G1IsAliveClosure;
205 friend class G1EvacuateFollowersClosure;
206 friend class G1ParScanThreadState;
207 friend class G1ParScanClosureSuper;
208 friend class G1ParEvacuateFollowersClosure;
209 friend class G1ParTask;
210 friend class G1FreeGarbageRegionClosure;
211 friend class RefineCardTableEntryClosure;
212 friend class G1PrepareCompactClosure;
213 friend class RegionSorter;
214 friend class RegionResetter;
215 friend class CountRCClosure;
216 friend class EvacPopObjClosure;
217 friend class G1ParCleanupCTTask;
219 // Other related classes.
220 friend class G1MarkSweep;
222 private:
223 // The one and only G1CollectedHeap, so static functions can find it.
224 static G1CollectedHeap* _g1h;
226 static size_t _humongous_object_threshold_in_words;
228 // Storage for the G1 heap (excludes the permanent generation).
229 VirtualSpace _g1_storage;
230 MemRegion _g1_reserved;
232 // The part of _g1_storage that is currently committed.
233 MemRegion _g1_committed;
235 // The master free list. It will satisfy all new region allocations.
236 MasterFreeRegionList _free_list;
238 // The secondary free list which contains regions that have been
239 // freed up during the cleanup process. This will be appended to the
240 // master free list when appropriate.
241 SecondaryFreeRegionList _secondary_free_list;
243 // It keeps track of the old regions.
244 MasterOldRegionSet _old_set;
246 // It keeps track of the humongous regions.
247 MasterHumongousRegionSet _humongous_set;
249 // The number of regions we could create by expansion.
250 uint _expansion_regions;
252 // The block offset table for the G1 heap.
253 G1BlockOffsetSharedArray* _bot_shared;
255 // Tears down the region sets / lists so that they are empty and the
256 // regions on the heap do not belong to a region set / list. The
257 // only exception is the humongous set which we leave unaltered. If
258 // free_list_only is true, it will only tear down the master free
259 // list. It is called before a Full GC (free_list_only == false) or
260 // before heap shrinking (free_list_only == true).
261 void tear_down_region_sets(bool free_list_only);
263 // Rebuilds the region sets / lists so that they are repopulated to
264 // reflect the contents of the heap. The only exception is the
265 // humongous set which was not torn down in the first place. If
266 // free_list_only is true, it will only rebuild the master free
267 // list. It is called after a Full GC (free_list_only == false) or
268 // after heap shrinking (free_list_only == true).
269 void rebuild_region_sets(bool free_list_only);
271 // The sequence of all heap regions in the heap.
272 HeapRegionSeq _hrs;
274 // Alloc region used to satisfy mutator allocation requests.
275 MutatorAllocRegion _mutator_alloc_region;
277 // Alloc region used to satisfy allocation requests by the GC for
278 // survivor objects.
279 SurvivorGCAllocRegion _survivor_gc_alloc_region;
281 // PLAB sizing policy for survivors.
282 PLABStats _survivor_plab_stats;
284 // Alloc region used to satisfy allocation requests by the GC for
285 // old objects.
286 OldGCAllocRegion _old_gc_alloc_region;
288 // PLAB sizing policy for tenured objects.
289 PLABStats _old_plab_stats;
291 PLABStats* stats_for_purpose(GCAllocPurpose purpose) {
292 PLABStats* stats = NULL;
294 switch (purpose) {
295 case GCAllocForSurvived:
296 stats = &_survivor_plab_stats;
297 break;
298 case GCAllocForTenured:
299 stats = &_old_plab_stats;
300 break;
301 default:
302 assert(false, "unrecognized GCAllocPurpose");
303 }
305 return stats;
306 }
308 // The last old region we allocated to during the last GC.
309 // Typically, it is not full so we should re-use it during the next GC.
310 HeapRegion* _retained_old_gc_alloc_region;
312 // It specifies whether we should attempt to expand the heap after a
313 // region allocation failure. If heap expansion fails we set this to
314 // false so that we don't re-attempt the heap expansion (it's likely
315 // that subsequent expansion attempts will also fail if one fails).
316 // Currently, it is only consulted during GC and it's reset at the
317 // start of each GC.
318 bool _expand_heap_after_alloc_failure;
320 // It resets the mutator alloc region before new allocations can take place.
321 void init_mutator_alloc_region();
323 // It releases the mutator alloc region.
324 void release_mutator_alloc_region();
326 // It initializes the GC alloc regions at the start of a GC.
327 void init_gc_alloc_regions();
329 // It releases the GC alloc regions at the end of a GC.
330 void release_gc_alloc_regions();
332 // It does any cleanup that needs to be done on the GC alloc regions
333 // before a Full GC.
334 void abandon_gc_alloc_regions();
336 // Helper for monitoring and management support.
337 G1MonitoringSupport* _g1mm;
339 // Determines PLAB size for a particular allocation purpose.
340 size_t desired_plab_sz(GCAllocPurpose purpose);
342 // Outside of GC pauses, the number of bytes used in all regions other
343 // than the current allocation region.
344 size_t _summary_bytes_used;
346 // This is used for a quick test on whether a reference points into
347 // the collection set or not. Basically, we have an array, with one
348 // byte per region, and that byte denotes whether the corresponding
349 // region is in the collection set or not. The entry corresponding
350 // the bottom of the heap, i.e., region 0, is pointed to by
351 // _in_cset_fast_test_base. The _in_cset_fast_test field has been
352 // biased so that it actually points to address 0 of the address
353 // space, to make the test as fast as possible (we can simply shift
354 // the address to address into it, instead of having to subtract the
355 // bottom of the heap from the address before shifting it; basically
356 // it works in the same way the card table works).
357 bool* _in_cset_fast_test;
359 // The allocated array used for the fast test on whether a reference
360 // points into the collection set or not. This field is also used to
361 // free the array.
362 bool* _in_cset_fast_test_base;
364 // The length of the _in_cset_fast_test_base array.
365 uint _in_cset_fast_test_length;
367 volatile unsigned _gc_time_stamp;
369 size_t* _surviving_young_words;
371 G1HRPrinter _hr_printer;
373 void setup_surviving_young_words();
374 void update_surviving_young_words(size_t* surv_young_words);
375 void cleanup_surviving_young_words();
377 // It decides whether an explicit GC should start a concurrent cycle
378 // instead of doing a STW GC. Currently, a concurrent cycle is
379 // explicitly started if:
380 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or
381 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent.
382 // (c) cause == _g1_humongous_allocation
383 bool should_do_concurrent_full_gc(GCCause::Cause cause);
385 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
386 // concurrent cycles) we have started.
387 volatile unsigned int _old_marking_cycles_started;
389 // Keeps track of how many "old marking cycles" (i.e., Full GCs or
390 // concurrent cycles) we have completed.
391 volatile unsigned int _old_marking_cycles_completed;
393 // This is a non-product method that is helpful for testing. It is
394 // called at the end of a GC and artificially expands the heap by
395 // allocating a number of dead regions. This way we can induce very
396 // frequent marking cycles and stress the cleanup / concurrent
397 // cleanup code more (as all the regions that will be allocated by
398 // this method will be found dead by the marking cycle).
399 void allocate_dummy_regions() PRODUCT_RETURN;
401 // Clear RSets after a compaction. It also resets the GC time stamps.
402 void clear_rsets_post_compaction();
404 // If the HR printer is active, dump the state of the regions in the
405 // heap after a compaction.
406 void print_hrs_post_compaction();
408 double verify(bool guard, const char* msg);
409 void verify_before_gc();
410 void verify_after_gc();
412 // These are macros so that, if the assert fires, we get the correct
413 // line number, file, etc.
415 #define heap_locking_asserts_err_msg(_extra_message_) \
416 err_msg("%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
417 (_extra_message_), \
418 BOOL_TO_STR(Heap_lock->owned_by_self()), \
419 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
420 BOOL_TO_STR(Thread::current()->is_VM_thread()))
422 #define assert_heap_locked() \
423 do { \
424 assert(Heap_lock->owned_by_self(), \
425 heap_locking_asserts_err_msg("should be holding the Heap_lock")); \
426 } while (0)
428 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
429 do { \
430 assert(Heap_lock->owned_by_self() || \
431 (SafepointSynchronize::is_at_safepoint() && \
432 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
433 heap_locking_asserts_err_msg("should be holding the Heap_lock or " \
434 "should be at a safepoint")); \
435 } while (0)
437 #define assert_heap_locked_and_not_at_safepoint() \
438 do { \
439 assert(Heap_lock->owned_by_self() && \
440 !SafepointSynchronize::is_at_safepoint(), \
441 heap_locking_asserts_err_msg("should be holding the Heap_lock and " \
442 "should not be at a safepoint")); \
443 } while (0)
445 #define assert_heap_not_locked() \
446 do { \
447 assert(!Heap_lock->owned_by_self(), \
448 heap_locking_asserts_err_msg("should not be holding the Heap_lock")); \
449 } while (0)
451 #define assert_heap_not_locked_and_not_at_safepoint() \
452 do { \
453 assert(!Heap_lock->owned_by_self() && \
454 !SafepointSynchronize::is_at_safepoint(), \
455 heap_locking_asserts_err_msg("should not be holding the Heap_lock and " \
456 "should not be at a safepoint")); \
457 } while (0)
459 #define assert_at_safepoint(_should_be_vm_thread_) \
460 do { \
461 assert(SafepointSynchronize::is_at_safepoint() && \
462 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread()), \
463 heap_locking_asserts_err_msg("should be at a safepoint")); \
464 } while (0)
466 #define assert_not_at_safepoint() \
467 do { \
468 assert(!SafepointSynchronize::is_at_safepoint(), \
469 heap_locking_asserts_err_msg("should not be at a safepoint")); \
470 } while (0)
472 protected:
474 // The young region list.
475 YoungList* _young_list;
477 // The current policy object for the collector.
478 G1CollectorPolicy* _g1_policy;
480 // This is the second level of trying to allocate a new region. If
481 // new_region() didn't find a region on the free_list, this call will
482 // check whether there's anything available on the
483 // secondary_free_list and/or wait for more regions to appear on
484 // that list, if _free_regions_coming is set.
485 HeapRegion* new_region_try_secondary_free_list();
487 // Try to allocate a single non-humongous HeapRegion sufficient for
488 // an allocation of the given word_size. If do_expand is true,
489 // attempt to expand the heap if necessary to satisfy the allocation
490 // request.
491 HeapRegion* new_region(size_t word_size, bool do_expand);
493 // Attempt to satisfy a humongous allocation request of the given
494 // size by finding a contiguous set of free regions of num_regions
495 // length and remove them from the master free list. Return the
496 // index of the first region or G1_NULL_HRS_INDEX if the search
497 // was unsuccessful.
498 uint humongous_obj_allocate_find_first(uint num_regions,
499 size_t word_size);
501 // Initialize a contiguous set of free regions of length num_regions
502 // and starting at index first so that they appear as a single
503 // humongous region.
504 HeapWord* humongous_obj_allocate_initialize_regions(uint first,
505 uint num_regions,
506 size_t word_size);
508 // Attempt to allocate a humongous object of the given size. Return
509 // NULL if unsuccessful.
510 HeapWord* humongous_obj_allocate(size_t word_size);
512 // The following two methods, allocate_new_tlab() and
513 // mem_allocate(), are the two main entry points from the runtime
514 // into the G1's allocation routines. They have the following
515 // assumptions:
516 //
517 // * They should both be called outside safepoints.
518 //
519 // * They should both be called without holding the Heap_lock.
520 //
521 // * All allocation requests for new TLABs should go to
522 // allocate_new_tlab().
523 //
524 // * All non-TLAB allocation requests should go to mem_allocate().
525 //
526 // * If either call cannot satisfy the allocation request using the
527 // current allocating region, they will try to get a new one. If
528 // this fails, they will attempt to do an evacuation pause and
529 // retry the allocation.
530 //
531 // * If all allocation attempts fail, even after trying to schedule
532 // an evacuation pause, allocate_new_tlab() will return NULL,
533 // whereas mem_allocate() will attempt a heap expansion and/or
534 // schedule a Full GC.
535 //
536 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
537 // should never be called with word_size being humongous. All
538 // humongous allocation requests should go to mem_allocate() which
539 // will satisfy them with a special path.
541 virtual HeapWord* allocate_new_tlab(size_t word_size);
543 virtual HeapWord* mem_allocate(size_t word_size,
544 bool* gc_overhead_limit_was_exceeded);
546 // The following three methods take a gc_count_before_ret
547 // parameter which is used to return the GC count if the method
548 // returns NULL. Given that we are required to read the GC count
549 // while holding the Heap_lock, and these paths will take the
550 // Heap_lock at some point, it's easier to get them to read the GC
551 // count while holding the Heap_lock before they return NULL instead
552 // of the caller (namely: mem_allocate()) having to also take the
553 // Heap_lock just to read the GC count.
555 // First-level mutator allocation attempt: try to allocate out of
556 // the mutator alloc region without taking the Heap_lock. This
557 // should only be used for non-humongous allocations.
558 inline HeapWord* attempt_allocation(size_t word_size,
559 unsigned int* gc_count_before_ret);
561 // Second-level mutator allocation attempt: take the Heap_lock and
562 // retry the allocation attempt, potentially scheduling a GC
563 // pause. This should only be used for non-humongous allocations.
564 HeapWord* attempt_allocation_slow(size_t word_size,
565 unsigned int* gc_count_before_ret);
567 // Takes the Heap_lock and attempts a humongous allocation. It can
568 // potentially schedule a GC pause.
569 HeapWord* attempt_allocation_humongous(size_t word_size,
570 unsigned int* gc_count_before_ret);
572 // Allocation attempt that should be called during safepoints (e.g.,
573 // at the end of a successful GC). expect_null_mutator_alloc_region
574 // specifies whether the mutator alloc region is expected to be NULL
575 // or not.
576 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
577 bool expect_null_mutator_alloc_region);
579 // It dirties the cards that cover the block so that so that the post
580 // write barrier never queues anything when updating objects on this
581 // block. It is assumed (and in fact we assert) that the block
582 // belongs to a young region.
583 inline void dirty_young_block(HeapWord* start, size_t word_size);
585 // Allocate blocks during garbage collection. Will ensure an
586 // allocation region, either by picking one or expanding the
587 // heap, and then allocate a block of the given size. The block
588 // may not be a humongous - it must fit into a single heap region.
589 HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size);
591 HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose,
592 HeapRegion* alloc_region,
593 bool par,
594 size_t word_size);
596 // Ensure that no further allocations can happen in "r", bearing in mind
597 // that parallel threads might be attempting allocations.
598 void par_allocate_remaining_space(HeapRegion* r);
600 // Allocation attempt during GC for a survivor object / PLAB.
601 inline HeapWord* survivor_attempt_allocation(size_t word_size);
603 // Allocation attempt during GC for an old object / PLAB.
604 inline HeapWord* old_attempt_allocation(size_t word_size);
606 // These methods are the "callbacks" from the G1AllocRegion class.
608 // For mutator alloc regions.
609 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force);
610 void retire_mutator_alloc_region(HeapRegion* alloc_region,
611 size_t allocated_bytes);
613 // For GC alloc regions.
614 HeapRegion* new_gc_alloc_region(size_t word_size, uint count,
615 GCAllocPurpose ap);
616 void retire_gc_alloc_region(HeapRegion* alloc_region,
617 size_t allocated_bytes, GCAllocPurpose ap);
619 // - if explicit_gc is true, the GC is for a System.gc() or a heap
620 // inspection request and should collect the entire heap
621 // - if clear_all_soft_refs is true, all soft references should be
622 // cleared during the GC
623 // - if explicit_gc is false, word_size describes the allocation that
624 // the GC should attempt (at least) to satisfy
625 // - it returns false if it is unable to do the collection due to the
626 // GC locker being active, true otherwise
627 bool do_collection(bool explicit_gc,
628 bool clear_all_soft_refs,
629 size_t word_size);
631 // Callback from VM_G1CollectFull operation.
632 // Perform a full collection.
633 void do_full_collection(bool clear_all_soft_refs);
635 // Resize the heap if necessary after a full collection. If this is
636 // after a collect-for allocation, "word_size" is the allocation size,
637 // and will be considered part of the used portion of the heap.
638 void resize_if_necessary_after_full_collection(size_t word_size);
640 // Callback from VM_G1CollectForAllocation operation.
641 // This function does everything necessary/possible to satisfy a
642 // failed allocation request (including collection, expansion, etc.)
643 HeapWord* satisfy_failed_allocation(size_t word_size, bool* succeeded);
645 // Attempting to expand the heap sufficiently
646 // to support an allocation of the given "word_size". If
647 // successful, perform the allocation and return the address of the
648 // allocated block, or else "NULL".
649 HeapWord* expand_and_allocate(size_t word_size);
651 // Process any reference objects discovered during
652 // an incremental evacuation pause.
653 void process_discovered_references();
655 // Enqueue any remaining discovered references
656 // after processing.
657 void enqueue_discovered_references();
659 public:
661 G1MonitoringSupport* g1mm() {
662 assert(_g1mm != NULL, "should have been initialized");
663 return _g1mm;
664 }
666 // Expand the garbage-first heap by at least the given size (in bytes!).
667 // Returns true if the heap was expanded by the requested amount;
668 // false otherwise.
669 // (Rounds up to a HeapRegion boundary.)
670 bool expand(size_t expand_bytes);
672 // Do anything common to GC's.
673 virtual void gc_prologue(bool full);
674 virtual void gc_epilogue(bool full);
676 // We register a region with the fast "in collection set" test. We
677 // simply set to true the array slot corresponding to this region.
678 void register_region_with_in_cset_fast_test(HeapRegion* r) {
679 assert(_in_cset_fast_test_base != NULL, "sanity");
680 assert(r->in_collection_set(), "invariant");
681 uint index = r->hrs_index();
682 assert(index < _in_cset_fast_test_length, "invariant");
683 assert(!_in_cset_fast_test_base[index], "invariant");
684 _in_cset_fast_test_base[index] = true;
685 }
687 // This is a fast test on whether a reference points into the
688 // collection set or not. It does not assume that the reference
689 // points into the heap; if it doesn't, it will return false.
690 bool in_cset_fast_test(oop obj) {
691 assert(_in_cset_fast_test != NULL, "sanity");
692 if (_g1_committed.contains((HeapWord*) obj)) {
693 // no need to subtract the bottom of the heap from obj,
694 // _in_cset_fast_test is biased
695 uintx index = (uintx) obj >> HeapRegion::LogOfHRGrainBytes;
696 bool ret = _in_cset_fast_test[index];
697 // let's make sure the result is consistent with what the slower
698 // test returns
699 assert( ret || !obj_in_cs(obj), "sanity");
700 assert(!ret || obj_in_cs(obj), "sanity");
701 return ret;
702 } else {
703 return false;
704 }
705 }
707 void clear_cset_fast_test() {
708 assert(_in_cset_fast_test_base != NULL, "sanity");
709 memset(_in_cset_fast_test_base, false,
710 (size_t) _in_cset_fast_test_length * sizeof(bool));
711 }
713 // This is called at the start of either a concurrent cycle or a Full
714 // GC to update the number of old marking cycles started.
715 void increment_old_marking_cycles_started();
717 // This is called at the end of either a concurrent cycle or a Full
718 // GC to update the number of old marking cycles completed. Those two
719 // can happen in a nested fashion, i.e., we start a concurrent
720 // cycle, a Full GC happens half-way through it which ends first,
721 // and then the cycle notices that a Full GC happened and ends
722 // too. The concurrent parameter is a boolean to help us do a bit
723 // tighter consistency checking in the method. If concurrent is
724 // false, the caller is the inner caller in the nesting (i.e., the
725 // Full GC). If concurrent is true, the caller is the outer caller
726 // in this nesting (i.e., the concurrent cycle). Further nesting is
727 // not currently supported. The end of this call also notifies
728 // the FullGCCount_lock in case a Java thread is waiting for a full
729 // GC to happen (e.g., it called System.gc() with
730 // +ExplicitGCInvokesConcurrent).
731 void increment_old_marking_cycles_completed(bool concurrent);
733 unsigned int old_marking_cycles_completed() {
734 return _old_marking_cycles_completed;
735 }
737 G1HRPrinter* hr_printer() { return &_hr_printer; }
739 protected:
741 // Shrink the garbage-first heap by at most the given size (in bytes!).
742 // (Rounds down to a HeapRegion boundary.)
743 virtual void shrink(size_t expand_bytes);
744 void shrink_helper(size_t expand_bytes);
746 #if TASKQUEUE_STATS
747 static void print_taskqueue_stats_hdr(outputStream* const st = gclog_or_tty);
748 void print_taskqueue_stats(outputStream* const st = gclog_or_tty) const;
749 void reset_taskqueue_stats();
750 #endif // TASKQUEUE_STATS
752 // Schedule the VM operation that will do an evacuation pause to
753 // satisfy an allocation request of word_size. *succeeded will
754 // return whether the VM operation was successful (it did do an
755 // evacuation pause) or not (another thread beat us to it or the GC
756 // locker was active). Given that we should not be holding the
757 // Heap_lock when we enter this method, we will pass the
758 // gc_count_before (i.e., total_collections()) as a parameter since
759 // it has to be read while holding the Heap_lock. Currently, both
760 // methods that call do_collection_pause() release the Heap_lock
761 // before the call, so it's easy to read gc_count_before just before.
762 HeapWord* do_collection_pause(size_t word_size,
763 unsigned int gc_count_before,
764 bool* succeeded);
766 // The guts of the incremental collection pause, executed by the vm
767 // thread. It returns false if it is unable to do the collection due
768 // to the GC locker being active, true otherwise
769 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
771 // Actually do the work of evacuating the collection set.
772 void evacuate_collection_set();
774 // The g1 remembered set of the heap.
775 G1RemSet* _g1_rem_set;
776 // And it's mod ref barrier set, used to track updates for the above.
777 ModRefBarrierSet* _mr_bs;
779 // A set of cards that cover the objects for which the Rsets should be updated
780 // concurrently after the collection.
781 DirtyCardQueueSet _dirty_card_queue_set;
783 // The Heap Region Rem Set Iterator.
784 HeapRegionRemSetIterator** _rem_set_iterator;
786 // The closure used to refine a single card.
787 RefineCardTableEntryClosure* _refine_cte_cl;
789 // A function to check the consistency of dirty card logs.
790 void check_ct_logs_at_safepoint();
792 // A DirtyCardQueueSet that is used to hold cards that contain
793 // references into the current collection set. This is used to
794 // update the remembered sets of the regions in the collection
795 // set in the event of an evacuation failure.
796 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
798 // After a collection pause, make the regions in the CS into free
799 // regions.
800 void free_collection_set(HeapRegion* cs_head);
802 // Abandon the current collection set without recording policy
803 // statistics or updating free lists.
804 void abandon_collection_set(HeapRegion* cs_head);
806 // Applies "scan_non_heap_roots" to roots outside the heap,
807 // "scan_rs" to roots inside the heap (having done "set_region" to
808 // indicate the region in which the root resides), and does "scan_perm"
809 // (setting the generation to the perm generation.) If "scan_rs" is
810 // NULL, then this step is skipped. The "worker_i"
811 // param is for use with parallel roots processing, and should be
812 // the "i" of the calling parallel worker thread's work(i) function.
813 // In the sequential case this param will be ignored.
814 void g1_process_strong_roots(bool collecting_perm_gen,
815 ScanningOption so,
816 OopClosure* scan_non_heap_roots,
817 OopsInHeapRegionClosure* scan_rs,
818 OopsInGenClosure* scan_perm,
819 int worker_i);
821 // Apply "blk" to all the weak roots of the system. These include
822 // JNI weak roots, the code cache, system dictionary, symbol table,
823 // string table, and referents of reachable weak refs.
824 void g1_process_weak_roots(OopClosure* root_closure,
825 OopClosure* non_root_closure);
827 // Frees a non-humongous region by initializing its contents and
828 // adding it to the free list that's passed as a parameter (this is
829 // usually a local list which will be appended to the master free
830 // list later). The used bytes of freed regions are accumulated in
831 // pre_used. If par is true, the region's RSet will not be freed
832 // up. The assumption is that this will be done later.
833 void free_region(HeapRegion* hr,
834 size_t* pre_used,
835 FreeRegionList* free_list,
836 bool par);
838 // Frees a humongous region by collapsing it into individual regions
839 // and calling free_region() for each of them. The freed regions
840 // will be added to the free list that's passed as a parameter (this
841 // is usually a local list which will be appended to the master free
842 // list later). The used bytes of freed regions are accumulated in
843 // pre_used. If par is true, the region's RSet will not be freed
844 // up. The assumption is that this will be done later.
845 void free_humongous_region(HeapRegion* hr,
846 size_t* pre_used,
847 FreeRegionList* free_list,
848 HumongousRegionSet* humongous_proxy_set,
849 bool par);
851 // Notifies all the necessary spaces that the committed space has
852 // been updated (either expanded or shrunk). It should be called
853 // after _g1_storage is updated.
854 void update_committed_space(HeapWord* old_end, HeapWord* new_end);
856 // The concurrent marker (and the thread it runs in.)
857 ConcurrentMark* _cm;
858 ConcurrentMarkThread* _cmThread;
859 bool _mark_in_progress;
861 // The concurrent refiner.
862 ConcurrentG1Refine* _cg1r;
864 // The parallel task queues
865 RefToScanQueueSet *_task_queues;
867 // True iff a evacuation has failed in the current collection.
868 bool _evacuation_failed;
870 // Set the attribute indicating whether evacuation has failed in the
871 // current collection.
872 void set_evacuation_failed(bool b) { _evacuation_failed = b; }
874 // Failed evacuations cause some logical from-space objects to have
875 // forwarding pointers to themselves. Reset them.
876 void remove_self_forwarding_pointers();
878 // When one is non-null, so is the other. Together, they each pair is
879 // an object with a preserved mark, and its mark value.
880 GrowableArray<oop>* _objs_with_preserved_marks;
881 GrowableArray<markOop>* _preserved_marks_of_objs;
883 // Preserve the mark of "obj", if necessary, in preparation for its mark
884 // word being overwritten with a self-forwarding-pointer.
885 void preserve_mark_if_necessary(oop obj, markOop m);
887 // The stack of evac-failure objects left to be scanned.
888 GrowableArray<oop>* _evac_failure_scan_stack;
889 // The closure to apply to evac-failure objects.
891 OopsInHeapRegionClosure* _evac_failure_closure;
892 // Set the field above.
893 void
894 set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) {
895 _evac_failure_closure = evac_failure_closure;
896 }
898 // Push "obj" on the scan stack.
899 void push_on_evac_failure_scan_stack(oop obj);
900 // Process scan stack entries until the stack is empty.
901 void drain_evac_failure_scan_stack();
902 // True iff an invocation of "drain_scan_stack" is in progress; to
903 // prevent unnecessary recursion.
904 bool _drain_in_progress;
906 // Do any necessary initialization for evacuation-failure handling.
907 // "cl" is the closure that will be used to process evac-failure
908 // objects.
909 void init_for_evac_failure(OopsInHeapRegionClosure* cl);
910 // Do any necessary cleanup for evacuation-failure handling data
911 // structures.
912 void finalize_for_evac_failure();
914 // An attempt to evacuate "obj" has failed; take necessary steps.
915 oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj);
916 void handle_evacuation_failure_common(oop obj, markOop m);
918 // ("Weak") Reference processing support.
919 //
920 // G1 has 2 instances of the referece processor class. One
921 // (_ref_processor_cm) handles reference object discovery
922 // and subsequent processing during concurrent marking cycles.
923 //
924 // The other (_ref_processor_stw) handles reference object
925 // discovery and processing during full GCs and incremental
926 // evacuation pauses.
927 //
928 // During an incremental pause, reference discovery will be
929 // temporarily disabled for _ref_processor_cm and will be
930 // enabled for _ref_processor_stw. At the end of the evacuation
931 // pause references discovered by _ref_processor_stw will be
932 // processed and discovery will be disabled. The previous
933 // setting for reference object discovery for _ref_processor_cm
934 // will be re-instated.
935 //
936 // At the start of marking:
937 // * Discovery by the CM ref processor is verified to be inactive
938 // and it's discovered lists are empty.
939 // * Discovery by the CM ref processor is then enabled.
940 //
941 // At the end of marking:
942 // * Any references on the CM ref processor's discovered
943 // lists are processed (possibly MT).
944 //
945 // At the start of full GC we:
946 // * Disable discovery by the CM ref processor and
947 // empty CM ref processor's discovered lists
948 // (without processing any entries).
949 // * Verify that the STW ref processor is inactive and it's
950 // discovered lists are empty.
951 // * Temporarily set STW ref processor discovery as single threaded.
952 // * Temporarily clear the STW ref processor's _is_alive_non_header
953 // field.
954 // * Finally enable discovery by the STW ref processor.
955 //
956 // The STW ref processor is used to record any discovered
957 // references during the full GC.
958 //
959 // At the end of a full GC we:
960 // * Enqueue any reference objects discovered by the STW ref processor
961 // that have non-live referents. This has the side-effect of
962 // making the STW ref processor inactive by disabling discovery.
963 // * Verify that the CM ref processor is still inactive
964 // and no references have been placed on it's discovered
965 // lists (also checked as a precondition during initial marking).
967 // The (stw) reference processor...
968 ReferenceProcessor* _ref_processor_stw;
970 // During reference object discovery, the _is_alive_non_header
971 // closure (if non-null) is applied to the referent object to
972 // determine whether the referent is live. If so then the
973 // reference object does not need to be 'discovered' and can
974 // be treated as a regular oop. This has the benefit of reducing
975 // the number of 'discovered' reference objects that need to
976 // be processed.
977 //
978 // Instance of the is_alive closure for embedding into the
979 // STW reference processor as the _is_alive_non_header field.
980 // Supplying a value for the _is_alive_non_header field is
981 // optional but doing so prevents unnecessary additions to
982 // the discovered lists during reference discovery.
983 G1STWIsAliveClosure _is_alive_closure_stw;
985 // The (concurrent marking) reference processor...
986 ReferenceProcessor* _ref_processor_cm;
988 // Instance of the concurrent mark is_alive closure for embedding
989 // into the Concurrent Marking reference processor as the
990 // _is_alive_non_header field. Supplying a value for the
991 // _is_alive_non_header field is optional but doing so prevents
992 // unnecessary additions to the discovered lists during reference
993 // discovery.
994 G1CMIsAliveClosure _is_alive_closure_cm;
996 // Cache used by G1CollectedHeap::start_cset_region_for_worker().
997 HeapRegion** _worker_cset_start_region;
999 // Time stamp to validate the regions recorded in the cache
1000 // used by G1CollectedHeap::start_cset_region_for_worker().
1001 // The heap region entry for a given worker is valid iff
1002 // the associated time stamp value matches the current value
1003 // of G1CollectedHeap::_gc_time_stamp.
1004 unsigned int* _worker_cset_start_region_time_stamp;
1006 enum G1H_process_strong_roots_tasks {
1007 G1H_PS_filter_satb_buffers,
1008 G1H_PS_refProcessor_oops_do,
1009 // Leave this one last.
1010 G1H_PS_NumElements
1011 };
1013 SubTasksDone* _process_strong_tasks;
1015 volatile bool _free_regions_coming;
1017 public:
1019 SubTasksDone* process_strong_tasks() { return _process_strong_tasks; }
1021 void set_refine_cte_cl_concurrency(bool concurrent);
1023 RefToScanQueue *task_queue(int i) const;
1025 // A set of cards where updates happened during the GC
1026 DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
1028 // A DirtyCardQueueSet that is used to hold cards that contain
1029 // references into the current collection set. This is used to
1030 // update the remembered sets of the regions in the collection
1031 // set in the event of an evacuation failure.
1032 DirtyCardQueueSet& into_cset_dirty_card_queue_set()
1033 { return _into_cset_dirty_card_queue_set; }
1035 // Create a G1CollectedHeap with the specified policy.
1036 // Must call the initialize method afterwards.
1037 // May not return if something goes wrong.
1038 G1CollectedHeap(G1CollectorPolicy* policy);
1040 // Initialize the G1CollectedHeap to have the initial and
1041 // maximum sizes, permanent generation, and remembered and barrier sets
1042 // specified by the policy object.
1043 jint initialize();
1045 // Initialize weak reference processing.
1046 virtual void ref_processing_init();
1048 void set_par_threads(uint t) {
1049 SharedHeap::set_par_threads(t);
1050 // Done in SharedHeap but oddly there are
1051 // two _process_strong_tasks's in a G1CollectedHeap
1052 // so do it here too.
1053 _process_strong_tasks->set_n_threads(t);
1054 }
1056 // Set _n_par_threads according to a policy TBD.
1057 void set_par_threads();
1059 void set_n_termination(int t) {
1060 _process_strong_tasks->set_n_threads(t);
1061 }
1063 virtual CollectedHeap::Name kind() const {
1064 return CollectedHeap::G1CollectedHeap;
1065 }
1067 // The current policy object for the collector.
1068 G1CollectorPolicy* g1_policy() const { return _g1_policy; }
1070 // Adaptive size policy. No such thing for g1.
1071 virtual AdaptiveSizePolicy* size_policy() { return NULL; }
1073 // The rem set and barrier set.
1074 G1RemSet* g1_rem_set() const { return _g1_rem_set; }
1075 ModRefBarrierSet* mr_bs() const { return _mr_bs; }
1077 // The rem set iterator.
1078 HeapRegionRemSetIterator* rem_set_iterator(int i) {
1079 return _rem_set_iterator[i];
1080 }
1082 HeapRegionRemSetIterator* rem_set_iterator() {
1083 return _rem_set_iterator[0];
1084 }
1086 unsigned get_gc_time_stamp() {
1087 return _gc_time_stamp;
1088 }
1090 void reset_gc_time_stamp() {
1091 _gc_time_stamp = 0;
1092 OrderAccess::fence();
1093 // Clear the cached CSet starting regions and time stamps.
1094 // Their validity is dependent on the GC timestamp.
1095 clear_cset_start_regions();
1096 }
1098 void check_gc_time_stamps() PRODUCT_RETURN;
1100 void increment_gc_time_stamp() {
1101 ++_gc_time_stamp;
1102 OrderAccess::fence();
1103 }
1105 // Reset the given region's GC timestamp. If it's starts humongous,
1106 // also reset the GC timestamp of its corresponding
1107 // continues humongous regions too.
1108 void reset_gc_time_stamps(HeapRegion* hr);
1110 void iterate_dirty_card_closure(CardTableEntryClosure* cl,
1111 DirtyCardQueue* into_cset_dcq,
1112 bool concurrent, int worker_i);
1114 // The shared block offset table array.
1115 G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; }
1117 // Reference Processing accessors
1119 // The STW reference processor....
1120 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; }
1122 // The Concurent Marking reference processor...
1123 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; }
1125 virtual size_t capacity() const;
1126 virtual size_t used() const;
1127 // This should be called when we're not holding the heap lock. The
1128 // result might be a bit inaccurate.
1129 size_t used_unlocked() const;
1130 size_t recalculate_used() const;
1132 // These virtual functions do the actual allocation.
1133 // Some heaps may offer a contiguous region for shared non-blocking
1134 // allocation, via inlined code (by exporting the address of the top and
1135 // end fields defining the extent of the contiguous allocation region.)
1136 // But G1CollectedHeap doesn't yet support this.
1138 // Return an estimate of the maximum allocation that could be performed
1139 // without triggering any collection or expansion activity. In a
1140 // generational collector, for example, this is probably the largest
1141 // allocation that could be supported (without expansion) in the youngest
1142 // generation. It is "unsafe" because no locks are taken; the result
1143 // should be treated as an approximation, not a guarantee, for use in
1144 // heuristic resizing decisions.
1145 virtual size_t unsafe_max_alloc();
1147 virtual bool is_maximal_no_gc() const {
1148 return _g1_storage.uncommitted_size() == 0;
1149 }
1151 // The total number of regions in the heap.
1152 uint n_regions() { return _hrs.length(); }
1154 // The max number of regions in the heap.
1155 uint max_regions() { return _hrs.max_length(); }
1157 // The number of regions that are completely free.
1158 uint free_regions() { return _free_list.length(); }
1160 // The number of regions that are not completely free.
1161 uint used_regions() { return n_regions() - free_regions(); }
1163 // The number of regions available for "regular" expansion.
1164 uint expansion_regions() { return _expansion_regions; }
1166 // Factory method for HeapRegion instances. It will return NULL if
1167 // the allocation fails.
1168 HeapRegion* new_heap_region(uint hrs_index, HeapWord* bottom);
1170 void verify_not_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
1171 void verify_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
1172 void verify_dirty_young_list(HeapRegion* head) PRODUCT_RETURN;
1173 void verify_dirty_young_regions() PRODUCT_RETURN;
1175 // verify_region_sets() performs verification over the region
1176 // lists. It will be compiled in the product code to be used when
1177 // necessary (i.e., during heap verification).
1178 void verify_region_sets();
1180 // verify_region_sets_optional() is planted in the code for
1181 // list verification in non-product builds (and it can be enabled in
1182 // product builds by definning HEAP_REGION_SET_FORCE_VERIFY to be 1).
1183 #if HEAP_REGION_SET_FORCE_VERIFY
1184 void verify_region_sets_optional() {
1185 verify_region_sets();
1186 }
1187 #else // HEAP_REGION_SET_FORCE_VERIFY
1188 void verify_region_sets_optional() { }
1189 #endif // HEAP_REGION_SET_FORCE_VERIFY
1191 #ifdef ASSERT
1192 bool is_on_master_free_list(HeapRegion* hr) {
1193 return hr->containing_set() == &_free_list;
1194 }
1196 bool is_in_humongous_set(HeapRegion* hr) {
1197 return hr->containing_set() == &_humongous_set;
1198 }
1199 #endif // ASSERT
1201 // Wrapper for the region list operations that can be called from
1202 // methods outside this class.
1204 void secondary_free_list_add_as_tail(FreeRegionList* list) {
1205 _secondary_free_list.add_as_tail(list);
1206 }
1208 void append_secondary_free_list() {
1209 _free_list.add_as_head(&_secondary_free_list);
1210 }
1212 void append_secondary_free_list_if_not_empty_with_lock() {
1213 // If the secondary free list looks empty there's no reason to
1214 // take the lock and then try to append it.
1215 if (!_secondary_free_list.is_empty()) {
1216 MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
1217 append_secondary_free_list();
1218 }
1219 }
1221 void old_set_remove(HeapRegion* hr) {
1222 _old_set.remove(hr);
1223 }
1225 size_t non_young_capacity_bytes() {
1226 return _old_set.total_capacity_bytes() + _humongous_set.total_capacity_bytes();
1227 }
1229 void set_free_regions_coming();
1230 void reset_free_regions_coming();
1231 bool free_regions_coming() { return _free_regions_coming; }
1232 void wait_while_free_regions_coming();
1234 // Determine whether the given region is one that we are using as an
1235 // old GC alloc region.
1236 bool is_old_gc_alloc_region(HeapRegion* hr) {
1237 return hr == _retained_old_gc_alloc_region;
1238 }
1240 // Perform a collection of the heap; intended for use in implementing
1241 // "System.gc". This probably implies as full a collection as the
1242 // "CollectedHeap" supports.
1243 virtual void collect(GCCause::Cause cause);
1245 // The same as above but assume that the caller holds the Heap_lock.
1246 void collect_locked(GCCause::Cause cause);
1248 // This interface assumes that it's being called by the
1249 // vm thread. It collects the heap assuming that the
1250 // heap lock is already held and that we are executing in
1251 // the context of the vm thread.
1252 virtual void collect_as_vm_thread(GCCause::Cause cause);
1254 // True iff a evacuation has failed in the most-recent collection.
1255 bool evacuation_failed() { return _evacuation_failed; }
1257 // It will free a region if it has allocated objects in it that are
1258 // all dead. It calls either free_region() or
1259 // free_humongous_region() depending on the type of the region that
1260 // is passed to it.
1261 void free_region_if_empty(HeapRegion* hr,
1262 size_t* pre_used,
1263 FreeRegionList* free_list,
1264 OldRegionSet* old_proxy_set,
1265 HumongousRegionSet* humongous_proxy_set,
1266 HRRSCleanupTask* hrrs_cleanup_task,
1267 bool par);
1269 // It appends the free list to the master free list and updates the
1270 // master humongous list according to the contents of the proxy
1271 // list. It also adjusts the total used bytes according to pre_used
1272 // (if par is true, it will do so by taking the ParGCRareEvent_lock).
1273 void update_sets_after_freeing_regions(size_t pre_used,
1274 FreeRegionList* free_list,
1275 OldRegionSet* old_proxy_set,
1276 HumongousRegionSet* humongous_proxy_set,
1277 bool par);
1279 // Returns "TRUE" iff "p" points into the committed areas of the heap.
1280 virtual bool is_in(const void* p) const;
1282 // Return "TRUE" iff the given object address is within the collection
1283 // set.
1284 inline bool obj_in_cs(oop obj);
1286 // Return "TRUE" iff the given object address is in the reserved
1287 // region of g1 (excluding the permanent generation).
1288 bool is_in_g1_reserved(const void* p) const {
1289 return _g1_reserved.contains(p);
1290 }
1292 // Returns a MemRegion that corresponds to the space that has been
1293 // reserved for the heap
1294 MemRegion g1_reserved() {
1295 return _g1_reserved;
1296 }
1298 // Returns a MemRegion that corresponds to the space that has been
1299 // committed in the heap
1300 MemRegion g1_committed() {
1301 return _g1_committed;
1302 }
1304 virtual bool is_in_closed_subset(const void* p) const;
1306 // This resets the card table to all zeros. It is used after
1307 // a collection pause which used the card table to claim cards.
1308 void cleanUpCardTable();
1310 // Iteration functions.
1312 // Iterate over all the ref-containing fields of all objects, calling
1313 // "cl.do_oop" on each.
1314 virtual void oop_iterate(OopClosure* cl) {
1315 oop_iterate(cl, true);
1316 }
1317 void oop_iterate(OopClosure* cl, bool do_perm);
1319 // Same as above, restricted to a memory region.
1320 virtual void oop_iterate(MemRegion mr, OopClosure* cl) {
1321 oop_iterate(mr, cl, true);
1322 }
1323 void oop_iterate(MemRegion mr, OopClosure* cl, bool do_perm);
1325 // Iterate over all objects, calling "cl.do_object" on each.
1326 virtual void object_iterate(ObjectClosure* cl) {
1327 object_iterate(cl, true);
1328 }
1329 virtual void safe_object_iterate(ObjectClosure* cl) {
1330 object_iterate(cl, true);
1331 }
1332 void object_iterate(ObjectClosure* cl, bool do_perm);
1334 // Iterate over all objects allocated since the last collection, calling
1335 // "cl.do_object" on each. The heap must have been initialized properly
1336 // to support this function, or else this call will fail.
1337 virtual void object_iterate_since_last_GC(ObjectClosure* cl);
1339 // Iterate over all spaces in use in the heap, in ascending address order.
1340 virtual void space_iterate(SpaceClosure* cl);
1342 // Iterate over heap regions, in address order, terminating the
1343 // iteration early if the "doHeapRegion" method returns "true".
1344 void heap_region_iterate(HeapRegionClosure* blk) const;
1346 // Return the region with the given index. It assumes the index is valid.
1347 HeapRegion* region_at(uint index) const { return _hrs.at(index); }
1349 // Divide the heap region sequence into "chunks" of some size (the number
1350 // of regions divided by the number of parallel threads times some
1351 // overpartition factor, currently 4). Assumes that this will be called
1352 // in parallel by ParallelGCThreads worker threads with discinct worker
1353 // ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel
1354 // calls will use the same "claim_value", and that that claim value is
1355 // different from the claim_value of any heap region before the start of
1356 // the iteration. Applies "blk->doHeapRegion" to each of the regions, by
1357 // attempting to claim the first region in each chunk, and, if
1358 // successful, applying the closure to each region in the chunk (and
1359 // setting the claim value of the second and subsequent regions of the
1360 // chunk.) For now requires that "doHeapRegion" always returns "false",
1361 // i.e., that a closure never attempt to abort a traversal.
1362 void heap_region_par_iterate_chunked(HeapRegionClosure* blk,
1363 uint worker,
1364 uint no_of_par_workers,
1365 jint claim_value);
1367 // It resets all the region claim values to the default.
1368 void reset_heap_region_claim_values();
1370 // Resets the claim values of regions in the current
1371 // collection set to the default.
1372 void reset_cset_heap_region_claim_values();
1374 #ifdef ASSERT
1375 bool check_heap_region_claim_values(jint claim_value);
1377 // Same as the routine above but only checks regions in the
1378 // current collection set.
1379 bool check_cset_heap_region_claim_values(jint claim_value);
1380 #endif // ASSERT
1382 // Clear the cached cset start regions and (more importantly)
1383 // the time stamps. Called when we reset the GC time stamp.
1384 void clear_cset_start_regions();
1386 // Given the id of a worker, obtain or calculate a suitable
1387 // starting region for iterating over the current collection set.
1388 HeapRegion* start_cset_region_for_worker(int worker_i);
1390 // This is a convenience method that is used by the
1391 // HeapRegionIterator classes to calculate the starting region for
1392 // each worker so that they do not all start from the same region.
1393 HeapRegion* start_region_for_worker(uint worker_i, uint no_of_par_workers);
1395 // Iterate over the regions (if any) in the current collection set.
1396 void collection_set_iterate(HeapRegionClosure* blk);
1398 // As above but starting from region r
1399 void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk);
1401 // Returns the first (lowest address) compactible space in the heap.
1402 virtual CompactibleSpace* first_compactible_space();
1404 // A CollectedHeap will contain some number of spaces. This finds the
1405 // space containing a given address, or else returns NULL.
1406 virtual Space* space_containing(const void* addr) const;
1408 // A G1CollectedHeap will contain some number of heap regions. This
1409 // finds the region containing a given address, or else returns NULL.
1410 template <class T>
1411 inline HeapRegion* heap_region_containing(const T addr) const;
1413 // Like the above, but requires "addr" to be in the heap (to avoid a
1414 // null-check), and unlike the above, may return an continuing humongous
1415 // region.
1416 template <class T>
1417 inline HeapRegion* heap_region_containing_raw(const T addr) const;
1419 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1420 // each address in the (reserved) heap is a member of exactly
1421 // one block. The defining characteristic of a block is that it is
1422 // possible to find its size, and thus to progress forward to the next
1423 // block. (Blocks may be of different sizes.) Thus, blocks may
1424 // represent Java objects, or they might be free blocks in a
1425 // free-list-based heap (or subheap), as long as the two kinds are
1426 // distinguishable and the size of each is determinable.
1428 // Returns the address of the start of the "block" that contains the
1429 // address "addr". We say "blocks" instead of "object" since some heaps
1430 // may not pack objects densely; a chunk may either be an object or a
1431 // non-object.
1432 virtual HeapWord* block_start(const void* addr) const;
1434 // Requires "addr" to be the start of a chunk, and returns its size.
1435 // "addr + size" is required to be the start of a new chunk, or the end
1436 // of the active area of the heap.
1437 virtual size_t block_size(const HeapWord* addr) const;
1439 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1440 // the block is an object.
1441 virtual bool block_is_obj(const HeapWord* addr) const;
1443 // Does this heap support heap inspection? (+PrintClassHistogram)
1444 virtual bool supports_heap_inspection() const { return true; }
1446 // Section on thread-local allocation buffers (TLABs)
1447 // See CollectedHeap for semantics.
1449 virtual bool supports_tlab_allocation() const;
1450 virtual size_t tlab_capacity(Thread* thr) const;
1451 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
1453 // Can a compiler initialize a new object without store barriers?
1454 // This permission only extends from the creation of a new object
1455 // via a TLAB up to the first subsequent safepoint. If such permission
1456 // is granted for this heap type, the compiler promises to call
1457 // defer_store_barrier() below on any slow path allocation of
1458 // a new object for which such initializing store barriers will
1459 // have been elided. G1, like CMS, allows this, but should be
1460 // ready to provide a compensating write barrier as necessary
1461 // if that storage came out of a non-young region. The efficiency
1462 // of this implementation depends crucially on being able to
1463 // answer very efficiently in constant time whether a piece of
1464 // storage in the heap comes from a young region or not.
1465 // See ReduceInitialCardMarks.
1466 virtual bool can_elide_tlab_store_barriers() const {
1467 return true;
1468 }
1470 virtual bool card_mark_must_follow_store() const {
1471 return true;
1472 }
1474 bool is_in_young(const oop obj) {
1475 HeapRegion* hr = heap_region_containing(obj);
1476 return hr != NULL && hr->is_young();
1477 }
1479 #ifdef ASSERT
1480 virtual bool is_in_partial_collection(const void* p);
1481 #endif
1483 virtual bool is_scavengable(const void* addr);
1485 // We don't need barriers for initializing stores to objects
1486 // in the young gen: for the SATB pre-barrier, there is no
1487 // pre-value that needs to be remembered; for the remembered-set
1488 // update logging post-barrier, we don't maintain remembered set
1489 // information for young gen objects.
1490 virtual bool can_elide_initializing_store_barrier(oop new_obj) {
1491 return is_in_young(new_obj);
1492 }
1494 // Can a compiler elide a store barrier when it writes
1495 // a permanent oop into the heap? Applies when the compiler
1496 // is storing x to the heap, where x->is_perm() is true.
1497 virtual bool can_elide_permanent_oop_store_barriers() const {
1498 // At least until perm gen collection is also G1-ified, at
1499 // which point this should return false.
1500 return true;
1501 }
1503 // Returns "true" iff the given word_size is "very large".
1504 static bool isHumongous(size_t word_size) {
1505 // Note this has to be strictly greater-than as the TLABs
1506 // are capped at the humongous thresold and we want to
1507 // ensure that we don't try to allocate a TLAB as
1508 // humongous and that we don't allocate a humongous
1509 // object in a TLAB.
1510 return word_size > _humongous_object_threshold_in_words;
1511 }
1513 // Update mod union table with the set of dirty cards.
1514 void updateModUnion();
1516 // Set the mod union bits corresponding to the given memRegion. Note
1517 // that this is always a safe operation, since it doesn't clear any
1518 // bits.
1519 void markModUnionRange(MemRegion mr);
1521 // Records the fact that a marking phase is no longer in progress.
1522 void set_marking_complete() {
1523 _mark_in_progress = false;
1524 }
1525 void set_marking_started() {
1526 _mark_in_progress = true;
1527 }
1528 bool mark_in_progress() {
1529 return _mark_in_progress;
1530 }
1532 // Print the maximum heap capacity.
1533 virtual size_t max_capacity() const;
1535 virtual jlong millis_since_last_gc();
1537 // Perform any cleanup actions necessary before allowing a verification.
1538 virtual void prepare_for_verify();
1540 // Perform verification.
1542 // vo == UsePrevMarking -> use "prev" marking information,
1543 // vo == UseNextMarking -> use "next" marking information
1544 // vo == UseMarkWord -> use the mark word in the object header
1545 //
1546 // NOTE: Only the "prev" marking information is guaranteed to be
1547 // consistent most of the time, so most calls to this should use
1548 // vo == UsePrevMarking.
1549 // Currently, there is only one case where this is called with
1550 // vo == UseNextMarking, which is to verify the "next" marking
1551 // information at the end of remark.
1552 // Currently there is only one place where this is called with
1553 // vo == UseMarkWord, which is to verify the marking during a
1554 // full GC.
1555 void verify(bool silent, VerifyOption vo);
1557 // Override; it uses the "prev" marking information
1558 virtual void verify(bool silent);
1559 virtual void print_on(outputStream* st) const;
1560 virtual void print_extended_on(outputStream* st) const;
1562 virtual void print_gc_threads_on(outputStream* st) const;
1563 virtual void gc_threads_do(ThreadClosure* tc) const;
1565 // Override
1566 void print_tracing_info() const;
1568 // The following two methods are helpful for debugging RSet issues.
1569 void print_cset_rsets() PRODUCT_RETURN;
1570 void print_all_rsets() PRODUCT_RETURN;
1572 // Convenience function to be used in situations where the heap type can be
1573 // asserted to be this type.
1574 static G1CollectedHeap* heap();
1576 void set_region_short_lived_locked(HeapRegion* hr);
1577 // add appropriate methods for any other surv rate groups
1579 YoungList* young_list() { return _young_list; }
1581 // debugging
1582 bool check_young_list_well_formed() {
1583 return _young_list->check_list_well_formed();
1584 }
1586 bool check_young_list_empty(bool check_heap,
1587 bool check_sample = true);
1589 // *** Stuff related to concurrent marking. It's not clear to me that so
1590 // many of these need to be public.
1592 // The functions below are helper functions that a subclass of
1593 // "CollectedHeap" can use in the implementation of its virtual
1594 // functions.
1595 // This performs a concurrent marking of the live objects in a
1596 // bitmap off to the side.
1597 void doConcurrentMark();
1599 bool isMarkedPrev(oop obj) const;
1600 bool isMarkedNext(oop obj) const;
1602 // Determine if an object is dead, given the object and also
1603 // the region to which the object belongs. An object is dead
1604 // iff a) it was not allocated since the last mark and b) it
1605 // is not marked.
1607 bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
1608 return
1609 !hr->obj_allocated_since_prev_marking(obj) &&
1610 !isMarkedPrev(obj);
1611 }
1613 // This function returns true when an object has been
1614 // around since the previous marking and hasn't yet
1615 // been marked during this marking.
1617 bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
1618 return
1619 !hr->obj_allocated_since_next_marking(obj) &&
1620 !isMarkedNext(obj);
1621 }
1623 // Determine if an object is dead, given only the object itself.
1624 // This will find the region to which the object belongs and
1625 // then call the region version of the same function.
1627 // Added if it is in permanent gen it isn't dead.
1628 // Added if it is NULL it isn't dead.
1630 bool is_obj_dead(const oop obj) const {
1631 const HeapRegion* hr = heap_region_containing(obj);
1632 if (hr == NULL) {
1633 if (Universe::heap()->is_in_permanent(obj))
1634 return false;
1635 else if (obj == NULL) return false;
1636 else return true;
1637 }
1638 else return is_obj_dead(obj, hr);
1639 }
1641 bool is_obj_ill(const oop obj) const {
1642 const HeapRegion* hr = heap_region_containing(obj);
1643 if (hr == NULL) {
1644 if (Universe::heap()->is_in_permanent(obj))
1645 return false;
1646 else if (obj == NULL) return false;
1647 else return true;
1648 }
1649 else return is_obj_ill(obj, hr);
1650 }
1652 // The methods below are here for convenience and dispatch the
1653 // appropriate method depending on value of the given VerifyOption
1654 // parameter. The options for that parameter are:
1655 //
1656 // vo == UsePrevMarking -> use "prev" marking information,
1657 // vo == UseNextMarking -> use "next" marking information,
1658 // vo == UseMarkWord -> use mark word from object header
1660 bool is_obj_dead_cond(const oop obj,
1661 const HeapRegion* hr,
1662 const VerifyOption vo) const {
1663 switch (vo) {
1664 case VerifyOption_G1UsePrevMarking: return is_obj_dead(obj, hr);
1665 case VerifyOption_G1UseNextMarking: return is_obj_ill(obj, hr);
1666 case VerifyOption_G1UseMarkWord: return !obj->is_gc_marked();
1667 default: ShouldNotReachHere();
1668 }
1669 return false; // keep some compilers happy
1670 }
1672 bool is_obj_dead_cond(const oop obj,
1673 const VerifyOption vo) const {
1674 switch (vo) {
1675 case VerifyOption_G1UsePrevMarking: return is_obj_dead(obj);
1676 case VerifyOption_G1UseNextMarking: return is_obj_ill(obj);
1677 case VerifyOption_G1UseMarkWord: return !obj->is_gc_marked();
1678 default: ShouldNotReachHere();
1679 }
1680 return false; // keep some compilers happy
1681 }
1683 bool allocated_since_marking(oop obj, HeapRegion* hr, VerifyOption vo);
1684 HeapWord* top_at_mark_start(HeapRegion* hr, VerifyOption vo);
1685 bool is_marked(oop obj, VerifyOption vo);
1686 const char* top_at_mark_start_str(VerifyOption vo);
1688 // The following is just to alert the verification code
1689 // that a full collection has occurred and that the
1690 // remembered sets are no longer up to date.
1691 bool _full_collection;
1692 void set_full_collection() { _full_collection = true;}
1693 void clear_full_collection() {_full_collection = false;}
1694 bool full_collection() {return _full_collection;}
1696 ConcurrentMark* concurrent_mark() const { return _cm; }
1697 ConcurrentG1Refine* concurrent_g1_refine() const { return _cg1r; }
1699 // The dirty cards region list is used to record a subset of regions
1700 // whose cards need clearing. The list if populated during the
1701 // remembered set scanning and drained during the card table
1702 // cleanup. Although the methods are reentrant, population/draining
1703 // phases must not overlap. For synchronization purposes the last
1704 // element on the list points to itself.
1705 HeapRegion* _dirty_cards_region_list;
1706 void push_dirty_cards_region(HeapRegion* hr);
1707 HeapRegion* pop_dirty_cards_region();
1709 public:
1710 void stop_conc_gc_threads();
1712 size_t pending_card_num();
1713 size_t cards_scanned();
1715 protected:
1716 size_t _max_heap_capacity;
1717 };
1719 class G1ParGCAllocBuffer: public ParGCAllocBuffer {
1720 private:
1721 bool _retired;
1723 public:
1724 G1ParGCAllocBuffer(size_t gclab_word_size);
1726 void set_buf(HeapWord* buf) {
1727 ParGCAllocBuffer::set_buf(buf);
1728 _retired = false;
1729 }
1731 void retire(bool end_of_gc, bool retain) {
1732 if (_retired)
1733 return;
1734 ParGCAllocBuffer::retire(end_of_gc, retain);
1735 _retired = true;
1736 }
1737 };
1739 class G1ParScanThreadState : public StackObj {
1740 protected:
1741 G1CollectedHeap* _g1h;
1742 RefToScanQueue* _refs;
1743 DirtyCardQueue _dcq;
1744 CardTableModRefBS* _ct_bs;
1745 G1RemSet* _g1_rem;
1747 G1ParGCAllocBuffer _surviving_alloc_buffer;
1748 G1ParGCAllocBuffer _tenured_alloc_buffer;
1749 G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount];
1750 ageTable _age_table;
1752 size_t _alloc_buffer_waste;
1753 size_t _undo_waste;
1755 OopsInHeapRegionClosure* _evac_failure_cl;
1756 G1ParScanHeapEvacClosure* _evac_cl;
1757 G1ParScanPartialArrayClosure* _partial_scan_cl;
1759 int _hash_seed;
1760 uint _queue_num;
1762 size_t _term_attempts;
1764 double _start;
1765 double _start_strong_roots;
1766 double _strong_roots_time;
1767 double _start_term;
1768 double _term_time;
1770 // Map from young-age-index (0 == not young, 1 is youngest) to
1771 // surviving words. base is what we get back from the malloc call
1772 size_t* _surviving_young_words_base;
1773 // this points into the array, as we use the first few entries for padding
1774 size_t* _surviving_young_words;
1776 #define PADDING_ELEM_NUM (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t))
1778 void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
1780 void add_to_undo_waste(size_t waste) { _undo_waste += waste; }
1782 DirtyCardQueue& dirty_card_queue() { return _dcq; }
1783 CardTableModRefBS* ctbs() { return _ct_bs; }
1785 template <class T> void immediate_rs_update(HeapRegion* from, T* p, int tid) {
1786 if (!from->is_survivor()) {
1787 _g1_rem->par_write_ref(from, p, tid);
1788 }
1789 }
1791 template <class T> void deferred_rs_update(HeapRegion* from, T* p, int tid) {
1792 // If the new value of the field points to the same region or
1793 // is the to-space, we don't need to include it in the Rset updates.
1794 if (!from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) && !from->is_survivor()) {
1795 size_t card_index = ctbs()->index_for(p);
1796 // If the card hasn't been added to the buffer, do it.
1797 if (ctbs()->mark_card_deferred(card_index)) {
1798 dirty_card_queue().enqueue((jbyte*)ctbs()->byte_for_index(card_index));
1799 }
1800 }
1801 }
1803 public:
1804 G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num);
1806 ~G1ParScanThreadState() {
1807 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base, mtGC);
1808 }
1810 RefToScanQueue* refs() { return _refs; }
1811 ageTable* age_table() { return &_age_table; }
1813 G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) {
1814 return _alloc_buffers[purpose];
1815 }
1817 size_t alloc_buffer_waste() const { return _alloc_buffer_waste; }
1818 size_t undo_waste() const { return _undo_waste; }
1820 #ifdef ASSERT
1821 bool verify_ref(narrowOop* ref) const;
1822 bool verify_ref(oop* ref) const;
1823 bool verify_task(StarTask ref) const;
1824 #endif // ASSERT
1826 template <class T> void push_on_queue(T* ref) {
1827 assert(verify_ref(ref), "sanity");
1828 refs()->push(ref);
1829 }
1831 template <class T> void update_rs(HeapRegion* from, T* p, int tid) {
1832 if (G1DeferredRSUpdate) {
1833 deferred_rs_update(from, p, tid);
1834 } else {
1835 immediate_rs_update(from, p, tid);
1836 }
1837 }
1839 HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz) {
1840 HeapWord* obj = NULL;
1841 size_t gclab_word_size = _g1h->desired_plab_sz(purpose);
1842 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
1843 G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose);
1844 add_to_alloc_buffer_waste(alloc_buf->words_remaining());
1845 alloc_buf->flush_stats_and_retire(_g1h->stats_for_purpose(purpose),
1846 false /* end_of_gc */,
1847 false /* retain */);
1849 HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size);
1850 if (buf == NULL) return NULL; // Let caller handle allocation failure.
1851 // Otherwise.
1852 alloc_buf->set_word_size(gclab_word_size);
1853 alloc_buf->set_buf(buf);
1855 obj = alloc_buf->allocate(word_sz);
1856 assert(obj != NULL, "buffer was definitely big enough...");
1857 } else {
1858 obj = _g1h->par_allocate_during_gc(purpose, word_sz);
1859 }
1860 return obj;
1861 }
1863 HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz) {
1864 HeapWord* obj = alloc_buffer(purpose)->allocate(word_sz);
1865 if (obj != NULL) return obj;
1866 return allocate_slow(purpose, word_sz);
1867 }
1869 void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz) {
1870 if (alloc_buffer(purpose)->contains(obj)) {
1871 assert(alloc_buffer(purpose)->contains(obj + word_sz - 1),
1872 "should contain whole object");
1873 alloc_buffer(purpose)->undo_allocation(obj, word_sz);
1874 } else {
1875 CollectedHeap::fill_with_object(obj, word_sz);
1876 add_to_undo_waste(word_sz);
1877 }
1878 }
1880 void set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_cl) {
1881 _evac_failure_cl = evac_failure_cl;
1882 }
1883 OopsInHeapRegionClosure* evac_failure_closure() {
1884 return _evac_failure_cl;
1885 }
1887 void set_evac_closure(G1ParScanHeapEvacClosure* evac_cl) {
1888 _evac_cl = evac_cl;
1889 }
1891 void set_partial_scan_closure(G1ParScanPartialArrayClosure* partial_scan_cl) {
1892 _partial_scan_cl = partial_scan_cl;
1893 }
1895 int* hash_seed() { return &_hash_seed; }
1896 uint queue_num() { return _queue_num; }
1898 size_t term_attempts() const { return _term_attempts; }
1899 void note_term_attempt() { _term_attempts++; }
1901 void start_strong_roots() {
1902 _start_strong_roots = os::elapsedTime();
1903 }
1904 void end_strong_roots() {
1905 _strong_roots_time += (os::elapsedTime() - _start_strong_roots);
1906 }
1907 double strong_roots_time() const { return _strong_roots_time; }
1909 void start_term_time() {
1910 note_term_attempt();
1911 _start_term = os::elapsedTime();
1912 }
1913 void end_term_time() {
1914 _term_time += (os::elapsedTime() - _start_term);
1915 }
1916 double term_time() const { return _term_time; }
1918 double elapsed_time() const {
1919 return os::elapsedTime() - _start;
1920 }
1922 static void
1923 print_termination_stats_hdr(outputStream* const st = gclog_or_tty);
1924 void
1925 print_termination_stats(int i, outputStream* const st = gclog_or_tty) const;
1927 size_t* surviving_young_words() {
1928 // We add on to hide entry 0 which accumulates surviving words for
1929 // age -1 regions (i.e. non-young ones)
1930 return _surviving_young_words;
1931 }
1933 void retire_alloc_buffers() {
1934 for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
1935 size_t waste = _alloc_buffers[ap]->words_remaining();
1936 add_to_alloc_buffer_waste(waste);
1937 _alloc_buffers[ap]->flush_stats_and_retire(_g1h->stats_for_purpose((GCAllocPurpose)ap),
1938 true /* end_of_gc */,
1939 false /* retain */);
1940 }
1941 }
1943 template <class T> void deal_with_reference(T* ref_to_scan) {
1944 if (has_partial_array_mask(ref_to_scan)) {
1945 _partial_scan_cl->do_oop_nv(ref_to_scan);
1946 } else {
1947 // Note: we can use "raw" versions of "region_containing" because
1948 // "obj_to_scan" is definitely in the heap, and is not in a
1949 // humongous region.
1950 HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
1951 _evac_cl->set_region(r);
1952 _evac_cl->do_oop_nv(ref_to_scan);
1953 }
1954 }
1956 void deal_with_reference(StarTask ref) {
1957 assert(verify_task(ref), "sanity");
1958 if (ref.is_narrow()) {
1959 deal_with_reference((narrowOop*)ref);
1960 } else {
1961 deal_with_reference((oop*)ref);
1962 }
1963 }
1965 public:
1966 void trim_queue();
1967 };
1969 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP