Fri, 24 Jun 2011 12:38:49 -0400
7049999: G1: Make the G1PrintHeapRegions output consistent and complete
Summary: Extend and make more consistent the output from the G1PrintHeapRegions flag.
Reviewed-by: johnc, jmasa
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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/parNew/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> RefToScanQueue;
66 typedef GenericTaskQueueSet<RefToScanQueue> 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 {
78 private:
79 G1CollectedHeap* _g1h;
81 HeapRegion* _head;
83 HeapRegion* _survivor_head;
84 HeapRegion* _survivor_tail;
86 HeapRegion* _curr;
88 size_t _length;
89 size_t _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 size_t length() { return _length; }
105 size_t 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 (length() - survivor_length()) * HeapRegion::GrainBytes;
115 }
116 size_t survivor_used_bytes() {
117 return 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 class RefineCardTableEntryClosure;
159 class G1CollectedHeap : public SharedHeap {
160 friend class VM_G1CollectForAllocation;
161 friend class VM_GenCollectForPermanentAllocation;
162 friend class VM_G1CollectFull;
163 friend class VM_G1IncCollectionPause;
164 friend class VMStructs;
165 friend class MutatorAllocRegion;
167 // Closures used in implementation.
168 friend class G1ParCopyHelper;
169 friend class G1IsAliveClosure;
170 friend class G1EvacuateFollowersClosure;
171 friend class G1ParScanThreadState;
172 friend class G1ParScanClosureSuper;
173 friend class G1ParEvacuateFollowersClosure;
174 friend class G1ParTask;
175 friend class G1FreeGarbageRegionClosure;
176 friend class RefineCardTableEntryClosure;
177 friend class G1PrepareCompactClosure;
178 friend class RegionSorter;
179 friend class RegionResetter;
180 friend class CountRCClosure;
181 friend class EvacPopObjClosure;
182 friend class G1ParCleanupCTTask;
184 // Other related classes.
185 friend class G1MarkSweep;
187 private:
188 // The one and only G1CollectedHeap, so static functions can find it.
189 static G1CollectedHeap* _g1h;
191 static size_t _humongous_object_threshold_in_words;
193 // Storage for the G1 heap (excludes the permanent generation).
194 VirtualSpace _g1_storage;
195 MemRegion _g1_reserved;
197 // The part of _g1_storage that is currently committed.
198 MemRegion _g1_committed;
200 // The master free list. It will satisfy all new region allocations.
201 MasterFreeRegionList _free_list;
203 // The secondary free list which contains regions that have been
204 // freed up during the cleanup process. This will be appended to the
205 // master free list when appropriate.
206 SecondaryFreeRegionList _secondary_free_list;
208 // It keeps track of the humongous regions.
209 MasterHumongousRegionSet _humongous_set;
211 // The number of regions we could create by expansion.
212 size_t _expansion_regions;
214 // The block offset table for the G1 heap.
215 G1BlockOffsetSharedArray* _bot_shared;
217 // Move all of the regions off the free lists, then rebuild those free
218 // lists, before and after full GC.
219 void tear_down_region_lists();
220 void rebuild_region_lists();
222 // The sequence of all heap regions in the heap.
223 HeapRegionSeq _hrs;
225 // Alloc region used to satisfy mutator allocation requests.
226 MutatorAllocRegion _mutator_alloc_region;
228 // It resets the mutator alloc region before new allocations can take place.
229 void init_mutator_alloc_region();
231 // It releases the mutator alloc region.
232 void release_mutator_alloc_region();
234 void abandon_gc_alloc_regions();
236 // The to-space memory regions into which objects are being copied during
237 // a GC.
238 HeapRegion* _gc_alloc_regions[GCAllocPurposeCount];
239 size_t _gc_alloc_region_counts[GCAllocPurposeCount];
240 // These are the regions, one per GCAllocPurpose, that are half-full
241 // at the end of a collection and that we want to reuse during the
242 // next collection.
243 HeapRegion* _retained_gc_alloc_regions[GCAllocPurposeCount];
244 // This specifies whether we will keep the last half-full region at
245 // the end of a collection so that it can be reused during the next
246 // collection (this is specified per GCAllocPurpose)
247 bool _retain_gc_alloc_region[GCAllocPurposeCount];
249 // A list of the regions that have been set to be alloc regions in the
250 // current collection.
251 HeapRegion* _gc_alloc_region_list;
253 // Helper for monitoring and management support.
254 G1MonitoringSupport* _g1mm;
256 // Determines PLAB size for a particular allocation purpose.
257 static size_t desired_plab_sz(GCAllocPurpose purpose);
259 // When called by par thread, requires the FreeList_lock to be held.
260 void push_gc_alloc_region(HeapRegion* hr);
262 // This should only be called single-threaded. Undeclares all GC alloc
263 // regions.
264 void forget_alloc_region_list();
266 // Should be used to set an alloc region, because there's other
267 // associated bookkeeping.
268 void set_gc_alloc_region(int purpose, HeapRegion* r);
270 // Check well-formedness of alloc region list.
271 bool check_gc_alloc_regions();
273 // Outside of GC pauses, the number of bytes used in all regions other
274 // than the current allocation region.
275 size_t _summary_bytes_used;
277 // This is used for a quick test on whether a reference points into
278 // the collection set or not. Basically, we have an array, with one
279 // byte per region, and that byte denotes whether the corresponding
280 // region is in the collection set or not. The entry corresponding
281 // the bottom of the heap, i.e., region 0, is pointed to by
282 // _in_cset_fast_test_base. The _in_cset_fast_test field has been
283 // biased so that it actually points to address 0 of the address
284 // space, to make the test as fast as possible (we can simply shift
285 // the address to address into it, instead of having to subtract the
286 // bottom of the heap from the address before shifting it; basically
287 // it works in the same way the card table works).
288 bool* _in_cset_fast_test;
290 // The allocated array used for the fast test on whether a reference
291 // points into the collection set or not. This field is also used to
292 // free the array.
293 bool* _in_cset_fast_test_base;
295 // The length of the _in_cset_fast_test_base array.
296 size_t _in_cset_fast_test_length;
298 volatile unsigned _gc_time_stamp;
300 size_t* _surviving_young_words;
302 G1HRPrinter _hr_printer;
304 void setup_surviving_young_words();
305 void update_surviving_young_words(size_t* surv_young_words);
306 void cleanup_surviving_young_words();
308 // It decides whether an explicit GC should start a concurrent cycle
309 // instead of doing a STW GC. Currently, a concurrent cycle is
310 // explicitly started if:
311 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or
312 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent.
313 bool should_do_concurrent_full_gc(GCCause::Cause cause);
315 // Keeps track of how many "full collections" (i.e., Full GCs or
316 // concurrent cycles) we have completed. The number of them we have
317 // started is maintained in _total_full_collections in CollectedHeap.
318 volatile unsigned int _full_collections_completed;
320 // This is a non-product method that is helpful for testing. It is
321 // called at the end of a GC and artificially expands the heap by
322 // allocating a number of dead regions. This way we can induce very
323 // frequent marking cycles and stress the cleanup / concurrent
324 // cleanup code more (as all the regions that will be allocated by
325 // this method will be found dead by the marking cycle).
326 void allocate_dummy_regions() PRODUCT_RETURN;
328 // These are macros so that, if the assert fires, we get the correct
329 // line number, file, etc.
331 #define heap_locking_asserts_err_msg(_extra_message_) \
332 err_msg("%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \
333 (_extra_message_), \
334 BOOL_TO_STR(Heap_lock->owned_by_self()), \
335 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \
336 BOOL_TO_STR(Thread::current()->is_VM_thread()))
338 #define assert_heap_locked() \
339 do { \
340 assert(Heap_lock->owned_by_self(), \
341 heap_locking_asserts_err_msg("should be holding the Heap_lock")); \
342 } while (0)
344 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \
345 do { \
346 assert(Heap_lock->owned_by_self() || \
347 (SafepointSynchronize::is_at_safepoint() && \
348 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \
349 heap_locking_asserts_err_msg("should be holding the Heap_lock or " \
350 "should be at a safepoint")); \
351 } while (0)
353 #define assert_heap_locked_and_not_at_safepoint() \
354 do { \
355 assert(Heap_lock->owned_by_self() && \
356 !SafepointSynchronize::is_at_safepoint(), \
357 heap_locking_asserts_err_msg("should be holding the Heap_lock and " \
358 "should not be at a safepoint")); \
359 } while (0)
361 #define assert_heap_not_locked() \
362 do { \
363 assert(!Heap_lock->owned_by_self(), \
364 heap_locking_asserts_err_msg("should not be holding the Heap_lock")); \
365 } while (0)
367 #define assert_heap_not_locked_and_not_at_safepoint() \
368 do { \
369 assert(!Heap_lock->owned_by_self() && \
370 !SafepointSynchronize::is_at_safepoint(), \
371 heap_locking_asserts_err_msg("should not be holding the Heap_lock and " \
372 "should not be at a safepoint")); \
373 } while (0)
375 #define assert_at_safepoint(_should_be_vm_thread_) \
376 do { \
377 assert(SafepointSynchronize::is_at_safepoint() && \
378 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread()), \
379 heap_locking_asserts_err_msg("should be at a safepoint")); \
380 } while (0)
382 #define assert_not_at_safepoint() \
383 do { \
384 assert(!SafepointSynchronize::is_at_safepoint(), \
385 heap_locking_asserts_err_msg("should not be at a safepoint")); \
386 } while (0)
388 protected:
390 // Returns "true" iff none of the gc alloc regions have any allocations
391 // since the last call to "save_marks".
392 bool all_alloc_regions_no_allocs_since_save_marks();
393 // Perform finalization stuff on all allocation regions.
394 void retire_all_alloc_regions();
396 // The number of regions allocated to hold humongous objects.
397 int _num_humongous_regions;
398 YoungList* _young_list;
400 // The current policy object for the collector.
401 G1CollectorPolicy* _g1_policy;
403 // This is the second level of trying to allocate a new region. If
404 // new_region() didn't find a region on the free_list, this call will
405 // check whether there's anything available on the
406 // secondary_free_list and/or wait for more regions to appear on
407 // that list, if _free_regions_coming is set.
408 HeapRegion* new_region_try_secondary_free_list();
410 // Try to allocate a single non-humongous HeapRegion sufficient for
411 // an allocation of the given word_size. If do_expand is true,
412 // attempt to expand the heap if necessary to satisfy the allocation
413 // request.
414 HeapRegion* new_region(size_t word_size, bool do_expand);
416 // Try to allocate a new region to be used for allocation by
417 // a GC thread. It will try to expand the heap if no region is
418 // available.
419 HeapRegion* new_gc_alloc_region(int purpose, size_t word_size);
421 // Attempt to satisfy a humongous allocation request of the given
422 // size by finding a contiguous set of free regions of num_regions
423 // length and remove them from the master free list. Return the
424 // index of the first region or G1_NULL_HRS_INDEX if the search
425 // was unsuccessful.
426 size_t humongous_obj_allocate_find_first(size_t num_regions,
427 size_t word_size);
429 // Initialize a contiguous set of free regions of length num_regions
430 // and starting at index first so that they appear as a single
431 // humongous region.
432 HeapWord* humongous_obj_allocate_initialize_regions(size_t first,
433 size_t num_regions,
434 size_t word_size);
436 // Attempt to allocate a humongous object of the given size. Return
437 // NULL if unsuccessful.
438 HeapWord* humongous_obj_allocate(size_t word_size);
440 // The following two methods, allocate_new_tlab() and
441 // mem_allocate(), are the two main entry points from the runtime
442 // into the G1's allocation routines. They have the following
443 // assumptions:
444 //
445 // * They should both be called outside safepoints.
446 //
447 // * They should both be called without holding the Heap_lock.
448 //
449 // * All allocation requests for new TLABs should go to
450 // allocate_new_tlab().
451 //
452 // * All non-TLAB allocation requests should go to mem_allocate().
453 //
454 // * If either call cannot satisfy the allocation request using the
455 // current allocating region, they will try to get a new one. If
456 // this fails, they will attempt to do an evacuation pause and
457 // retry the allocation.
458 //
459 // * If all allocation attempts fail, even after trying to schedule
460 // an evacuation pause, allocate_new_tlab() will return NULL,
461 // whereas mem_allocate() will attempt a heap expansion and/or
462 // schedule a Full GC.
463 //
464 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab
465 // should never be called with word_size being humongous. All
466 // humongous allocation requests should go to mem_allocate() which
467 // will satisfy them with a special path.
469 virtual HeapWord* allocate_new_tlab(size_t word_size);
471 virtual HeapWord* mem_allocate(size_t word_size,
472 bool* gc_overhead_limit_was_exceeded);
474 // The following three methods take a gc_count_before_ret
475 // parameter which is used to return the GC count if the method
476 // returns NULL. Given that we are required to read the GC count
477 // while holding the Heap_lock, and these paths will take the
478 // Heap_lock at some point, it's easier to get them to read the GC
479 // count while holding the Heap_lock before they return NULL instead
480 // of the caller (namely: mem_allocate()) having to also take the
481 // Heap_lock just to read the GC count.
483 // First-level mutator allocation attempt: try to allocate out of
484 // the mutator alloc region without taking the Heap_lock. This
485 // should only be used for non-humongous allocations.
486 inline HeapWord* attempt_allocation(size_t word_size,
487 unsigned int* gc_count_before_ret);
489 // Second-level mutator allocation attempt: take the Heap_lock and
490 // retry the allocation attempt, potentially scheduling a GC
491 // pause. This should only be used for non-humongous allocations.
492 HeapWord* attempt_allocation_slow(size_t word_size,
493 unsigned int* gc_count_before_ret);
495 // Takes the Heap_lock and attempts a humongous allocation. It can
496 // potentially schedule a GC pause.
497 HeapWord* attempt_allocation_humongous(size_t word_size,
498 unsigned int* gc_count_before_ret);
500 // Allocation attempt that should be called during safepoints (e.g.,
501 // at the end of a successful GC). expect_null_mutator_alloc_region
502 // specifies whether the mutator alloc region is expected to be NULL
503 // or not.
504 HeapWord* attempt_allocation_at_safepoint(size_t word_size,
505 bool expect_null_mutator_alloc_region);
507 // It dirties the cards that cover the block so that so that the post
508 // write barrier never queues anything when updating objects on this
509 // block. It is assumed (and in fact we assert) that the block
510 // belongs to a young region.
511 inline void dirty_young_block(HeapWord* start, size_t word_size);
513 // Allocate blocks during garbage collection. Will ensure an
514 // allocation region, either by picking one or expanding the
515 // heap, and then allocate a block of the given size. The block
516 // may not be a humongous - it must fit into a single heap region.
517 HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size);
519 HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose,
520 HeapRegion* alloc_region,
521 bool par,
522 size_t word_size);
524 // Ensure that no further allocations can happen in "r", bearing in mind
525 // that parallel threads might be attempting allocations.
526 void par_allocate_remaining_space(HeapRegion* r);
528 // Retires an allocation region when it is full or at the end of a
529 // GC pause.
530 void retire_alloc_region(HeapRegion* alloc_region, bool par);
532 // These two methods are the "callbacks" from the G1AllocRegion class.
534 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force);
535 void retire_mutator_alloc_region(HeapRegion* alloc_region,
536 size_t allocated_bytes);
538 // - if explicit_gc is true, the GC is for a System.gc() or a heap
539 // inspection request and should collect the entire heap
540 // - if clear_all_soft_refs is true, all soft references should be
541 // cleared during the GC
542 // - if explicit_gc is false, word_size describes the allocation that
543 // the GC should attempt (at least) to satisfy
544 // - it returns false if it is unable to do the collection due to the
545 // GC locker being active, true otherwise
546 bool do_collection(bool explicit_gc,
547 bool clear_all_soft_refs,
548 size_t word_size);
550 // Callback from VM_G1CollectFull operation.
551 // Perform a full collection.
552 void do_full_collection(bool clear_all_soft_refs);
554 // Resize the heap if necessary after a full collection. If this is
555 // after a collect-for allocation, "word_size" is the allocation size,
556 // and will be considered part of the used portion of the heap.
557 void resize_if_necessary_after_full_collection(size_t word_size);
559 // Callback from VM_G1CollectForAllocation operation.
560 // This function does everything necessary/possible to satisfy a
561 // failed allocation request (including collection, expansion, etc.)
562 HeapWord* satisfy_failed_allocation(size_t word_size, bool* succeeded);
564 // Attempting to expand the heap sufficiently
565 // to support an allocation of the given "word_size". If
566 // successful, perform the allocation and return the address of the
567 // allocated block, or else "NULL".
568 HeapWord* expand_and_allocate(size_t word_size);
570 public:
572 G1MonitoringSupport* g1mm() { return _g1mm; }
574 // Expand the garbage-first heap by at least the given size (in bytes!).
575 // Returns true if the heap was expanded by the requested amount;
576 // false otherwise.
577 // (Rounds up to a HeapRegion boundary.)
578 bool expand(size_t expand_bytes);
580 // Do anything common to GC's.
581 virtual void gc_prologue(bool full);
582 virtual void gc_epilogue(bool full);
584 // We register a region with the fast "in collection set" test. We
585 // simply set to true the array slot corresponding to this region.
586 void register_region_with_in_cset_fast_test(HeapRegion* r) {
587 assert(_in_cset_fast_test_base != NULL, "sanity");
588 assert(r->in_collection_set(), "invariant");
589 size_t index = r->hrs_index();
590 assert(index < _in_cset_fast_test_length, "invariant");
591 assert(!_in_cset_fast_test_base[index], "invariant");
592 _in_cset_fast_test_base[index] = true;
593 }
595 // This is a fast test on whether a reference points into the
596 // collection set or not. It does not assume that the reference
597 // points into the heap; if it doesn't, it will return false.
598 bool in_cset_fast_test(oop obj) {
599 assert(_in_cset_fast_test != NULL, "sanity");
600 if (_g1_committed.contains((HeapWord*) obj)) {
601 // no need to subtract the bottom of the heap from obj,
602 // _in_cset_fast_test is biased
603 size_t index = ((size_t) obj) >> HeapRegion::LogOfHRGrainBytes;
604 bool ret = _in_cset_fast_test[index];
605 // let's make sure the result is consistent with what the slower
606 // test returns
607 assert( ret || !obj_in_cs(obj), "sanity");
608 assert(!ret || obj_in_cs(obj), "sanity");
609 return ret;
610 } else {
611 return false;
612 }
613 }
615 void clear_cset_fast_test() {
616 assert(_in_cset_fast_test_base != NULL, "sanity");
617 memset(_in_cset_fast_test_base, false,
618 _in_cset_fast_test_length * sizeof(bool));
619 }
621 // This is called at the end of either a concurrent cycle or a Full
622 // GC to update the number of full collections completed. Those two
623 // can happen in a nested fashion, i.e., we start a concurrent
624 // cycle, a Full GC happens half-way through it which ends first,
625 // and then the cycle notices that a Full GC happened and ends
626 // too. The concurrent parameter is a boolean to help us do a bit
627 // tighter consistency checking in the method. If concurrent is
628 // false, the caller is the inner caller in the nesting (i.e., the
629 // Full GC). If concurrent is true, the caller is the outer caller
630 // in this nesting (i.e., the concurrent cycle). Further nesting is
631 // not currently supported. The end of the this call also notifies
632 // the FullGCCount_lock in case a Java thread is waiting for a full
633 // GC to happen (e.g., it called System.gc() with
634 // +ExplicitGCInvokesConcurrent).
635 void increment_full_collections_completed(bool concurrent);
637 unsigned int full_collections_completed() {
638 return _full_collections_completed;
639 }
641 G1HRPrinter* hr_printer() { return &_hr_printer; }
643 protected:
645 // Shrink the garbage-first heap by at most the given size (in bytes!).
646 // (Rounds down to a HeapRegion boundary.)
647 virtual void shrink(size_t expand_bytes);
648 void shrink_helper(size_t expand_bytes);
650 #if TASKQUEUE_STATS
651 static void print_taskqueue_stats_hdr(outputStream* const st = gclog_or_tty);
652 void print_taskqueue_stats(outputStream* const st = gclog_or_tty) const;
653 void reset_taskqueue_stats();
654 #endif // TASKQUEUE_STATS
656 // Schedule the VM operation that will do an evacuation pause to
657 // satisfy an allocation request of word_size. *succeeded will
658 // return whether the VM operation was successful (it did do an
659 // evacuation pause) or not (another thread beat us to it or the GC
660 // locker was active). Given that we should not be holding the
661 // Heap_lock when we enter this method, we will pass the
662 // gc_count_before (i.e., total_collections()) as a parameter since
663 // it has to be read while holding the Heap_lock. Currently, both
664 // methods that call do_collection_pause() release the Heap_lock
665 // before the call, so it's easy to read gc_count_before just before.
666 HeapWord* do_collection_pause(size_t word_size,
667 unsigned int gc_count_before,
668 bool* succeeded);
670 // The guts of the incremental collection pause, executed by the vm
671 // thread. It returns false if it is unable to do the collection due
672 // to the GC locker being active, true otherwise
673 bool do_collection_pause_at_safepoint(double target_pause_time_ms);
675 // Actually do the work of evacuating the collection set.
676 void evacuate_collection_set();
678 // The g1 remembered set of the heap.
679 G1RemSet* _g1_rem_set;
680 // And it's mod ref barrier set, used to track updates for the above.
681 ModRefBarrierSet* _mr_bs;
683 // A set of cards that cover the objects for which the Rsets should be updated
684 // concurrently after the collection.
685 DirtyCardQueueSet _dirty_card_queue_set;
687 // The Heap Region Rem Set Iterator.
688 HeapRegionRemSetIterator** _rem_set_iterator;
690 // The closure used to refine a single card.
691 RefineCardTableEntryClosure* _refine_cte_cl;
693 // A function to check the consistency of dirty card logs.
694 void check_ct_logs_at_safepoint();
696 // A DirtyCardQueueSet that is used to hold cards that contain
697 // references into the current collection set. This is used to
698 // update the remembered sets of the regions in the collection
699 // set in the event of an evacuation failure.
700 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
702 // After a collection pause, make the regions in the CS into free
703 // regions.
704 void free_collection_set(HeapRegion* cs_head);
706 // Abandon the current collection set without recording policy
707 // statistics or updating free lists.
708 void abandon_collection_set(HeapRegion* cs_head);
710 // Applies "scan_non_heap_roots" to roots outside the heap,
711 // "scan_rs" to roots inside the heap (having done "set_region" to
712 // indicate the region in which the root resides), and does "scan_perm"
713 // (setting the generation to the perm generation.) If "scan_rs" is
714 // NULL, then this step is skipped. The "worker_i"
715 // param is for use with parallel roots processing, and should be
716 // the "i" of the calling parallel worker thread's work(i) function.
717 // In the sequential case this param will be ignored.
718 void g1_process_strong_roots(bool collecting_perm_gen,
719 SharedHeap::ScanningOption so,
720 OopClosure* scan_non_heap_roots,
721 OopsInHeapRegionClosure* scan_rs,
722 OopsInGenClosure* scan_perm,
723 int worker_i);
725 // Apply "blk" to all the weak roots of the system. These include
726 // JNI weak roots, the code cache, system dictionary, symbol table,
727 // string table, and referents of reachable weak refs.
728 void g1_process_weak_roots(OopClosure* root_closure,
729 OopClosure* non_root_closure);
731 // Invoke "save_marks" on all heap regions.
732 void save_marks();
734 // Frees a non-humongous region by initializing its contents and
735 // adding it to the free list that's passed as a parameter (this is
736 // usually a local list which will be appended to the master free
737 // list later). The used bytes of freed regions are accumulated in
738 // pre_used. If par is true, the region's RSet will not be freed
739 // up. The assumption is that this will be done later.
740 void free_region(HeapRegion* hr,
741 size_t* pre_used,
742 FreeRegionList* free_list,
743 bool par);
745 // Frees a humongous region by collapsing it into individual regions
746 // and calling free_region() for each of them. The freed regions
747 // will be added to the free list that's passed as a parameter (this
748 // is usually a local list which will be appended to the master free
749 // list later). The used bytes of freed regions are accumulated in
750 // pre_used. If par is true, the region's RSet will not be freed
751 // up. The assumption is that this will be done later.
752 void free_humongous_region(HeapRegion* hr,
753 size_t* pre_used,
754 FreeRegionList* free_list,
755 HumongousRegionSet* humongous_proxy_set,
756 bool par);
758 // Notifies all the necessary spaces that the committed space has
759 // been updated (either expanded or shrunk). It should be called
760 // after _g1_storage is updated.
761 void update_committed_space(HeapWord* old_end, HeapWord* new_end);
763 // The concurrent marker (and the thread it runs in.)
764 ConcurrentMark* _cm;
765 ConcurrentMarkThread* _cmThread;
766 bool _mark_in_progress;
768 // The concurrent refiner.
769 ConcurrentG1Refine* _cg1r;
771 // The parallel task queues
772 RefToScanQueueSet *_task_queues;
774 // True iff a evacuation has failed in the current collection.
775 bool _evacuation_failed;
777 // Set the attribute indicating whether evacuation has failed in the
778 // current collection.
779 void set_evacuation_failed(bool b) { _evacuation_failed = b; }
781 // Failed evacuations cause some logical from-space objects to have
782 // forwarding pointers to themselves. Reset them.
783 void remove_self_forwarding_pointers();
785 // When one is non-null, so is the other. Together, they each pair is
786 // an object with a preserved mark, and its mark value.
787 GrowableArray<oop>* _objs_with_preserved_marks;
788 GrowableArray<markOop>* _preserved_marks_of_objs;
790 // Preserve the mark of "obj", if necessary, in preparation for its mark
791 // word being overwritten with a self-forwarding-pointer.
792 void preserve_mark_if_necessary(oop obj, markOop m);
794 // The stack of evac-failure objects left to be scanned.
795 GrowableArray<oop>* _evac_failure_scan_stack;
796 // The closure to apply to evac-failure objects.
798 OopsInHeapRegionClosure* _evac_failure_closure;
799 // Set the field above.
800 void
801 set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) {
802 _evac_failure_closure = evac_failure_closure;
803 }
805 // Push "obj" on the scan stack.
806 void push_on_evac_failure_scan_stack(oop obj);
807 // Process scan stack entries until the stack is empty.
808 void drain_evac_failure_scan_stack();
809 // True iff an invocation of "drain_scan_stack" is in progress; to
810 // prevent unnecessary recursion.
811 bool _drain_in_progress;
813 // Do any necessary initialization for evacuation-failure handling.
814 // "cl" is the closure that will be used to process evac-failure
815 // objects.
816 void init_for_evac_failure(OopsInHeapRegionClosure* cl);
817 // Do any necessary cleanup for evacuation-failure handling data
818 // structures.
819 void finalize_for_evac_failure();
821 // An attempt to evacuate "obj" has failed; take necessary steps.
822 oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj);
823 void handle_evacuation_failure_common(oop obj, markOop m);
825 // Ensure that the relevant gc_alloc regions are set.
826 void get_gc_alloc_regions();
827 // We're done with GC alloc regions. We are going to tear down the
828 // gc alloc list and remove the gc alloc tag from all the regions on
829 // that list. However, we will also retain the last (i.e., the one
830 // that is half-full) GC alloc region, per GCAllocPurpose, for
831 // possible reuse during the next collection, provided
832 // _retain_gc_alloc_region[] indicates that it should be the
833 // case. Said regions are kept in the _retained_gc_alloc_regions[]
834 // array. If the parameter totally is set, we will not retain any
835 // regions, irrespective of what _retain_gc_alloc_region[]
836 // indicates.
837 void release_gc_alloc_regions(bool totally);
838 #ifndef PRODUCT
839 // Useful for debugging.
840 void print_gc_alloc_regions();
841 #endif // !PRODUCT
843 // Instance of the concurrent mark is_alive closure for embedding
844 // into the reference processor as the is_alive_non_header. This
845 // prevents unnecessary additions to the discovered lists during
846 // concurrent discovery.
847 G1CMIsAliveClosure _is_alive_closure;
849 // ("Weak") Reference processing support
850 ReferenceProcessor* _ref_processor;
852 enum G1H_process_strong_roots_tasks {
853 G1H_PS_mark_stack_oops_do,
854 G1H_PS_refProcessor_oops_do,
855 // Leave this one last.
856 G1H_PS_NumElements
857 };
859 SubTasksDone* _process_strong_tasks;
861 volatile bool _free_regions_coming;
863 public:
865 SubTasksDone* process_strong_tasks() { return _process_strong_tasks; }
867 void set_refine_cte_cl_concurrency(bool concurrent);
869 RefToScanQueue *task_queue(int i) const;
871 // A set of cards where updates happened during the GC
872 DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
874 // A DirtyCardQueueSet that is used to hold cards that contain
875 // references into the current collection set. This is used to
876 // update the remembered sets of the regions in the collection
877 // set in the event of an evacuation failure.
878 DirtyCardQueueSet& into_cset_dirty_card_queue_set()
879 { return _into_cset_dirty_card_queue_set; }
881 // Create a G1CollectedHeap with the specified policy.
882 // Must call the initialize method afterwards.
883 // May not return if something goes wrong.
884 G1CollectedHeap(G1CollectorPolicy* policy);
886 // Initialize the G1CollectedHeap to have the initial and
887 // maximum sizes, permanent generation, and remembered and barrier sets
888 // specified by the policy object.
889 jint initialize();
891 virtual void ref_processing_init();
893 void set_par_threads(int t) {
894 SharedHeap::set_par_threads(t);
895 _process_strong_tasks->set_n_threads(t);
896 }
898 virtual CollectedHeap::Name kind() const {
899 return CollectedHeap::G1CollectedHeap;
900 }
902 // The current policy object for the collector.
903 G1CollectorPolicy* g1_policy() const { return _g1_policy; }
905 // Adaptive size policy. No such thing for g1.
906 virtual AdaptiveSizePolicy* size_policy() { return NULL; }
908 // The rem set and barrier set.
909 G1RemSet* g1_rem_set() const { return _g1_rem_set; }
910 ModRefBarrierSet* mr_bs() const { return _mr_bs; }
912 // The rem set iterator.
913 HeapRegionRemSetIterator* rem_set_iterator(int i) {
914 return _rem_set_iterator[i];
915 }
917 HeapRegionRemSetIterator* rem_set_iterator() {
918 return _rem_set_iterator[0];
919 }
921 unsigned get_gc_time_stamp() {
922 return _gc_time_stamp;
923 }
925 void reset_gc_time_stamp() {
926 _gc_time_stamp = 0;
927 OrderAccess::fence();
928 }
930 void increment_gc_time_stamp() {
931 ++_gc_time_stamp;
932 OrderAccess::fence();
933 }
935 void iterate_dirty_card_closure(CardTableEntryClosure* cl,
936 DirtyCardQueue* into_cset_dcq,
937 bool concurrent, int worker_i);
939 // The shared block offset table array.
940 G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; }
942 // Reference Processing accessor
943 ReferenceProcessor* ref_processor() { return _ref_processor; }
945 virtual size_t capacity() const;
946 virtual size_t used() const;
947 // This should be called when we're not holding the heap lock. The
948 // result might be a bit inaccurate.
949 size_t used_unlocked() const;
950 size_t recalculate_used() const;
951 #ifndef PRODUCT
952 size_t recalculate_used_regions() const;
953 #endif // PRODUCT
955 // These virtual functions do the actual allocation.
956 // Some heaps may offer a contiguous region for shared non-blocking
957 // allocation, via inlined code (by exporting the address of the top and
958 // end fields defining the extent of the contiguous allocation region.)
959 // But G1CollectedHeap doesn't yet support this.
961 // Return an estimate of the maximum allocation that could be performed
962 // without triggering any collection or expansion activity. In a
963 // generational collector, for example, this is probably the largest
964 // allocation that could be supported (without expansion) in the youngest
965 // generation. It is "unsafe" because no locks are taken; the result
966 // should be treated as an approximation, not a guarantee, for use in
967 // heuristic resizing decisions.
968 virtual size_t unsafe_max_alloc();
970 virtual bool is_maximal_no_gc() const {
971 return _g1_storage.uncommitted_size() == 0;
972 }
974 // The total number of regions in the heap.
975 size_t n_regions() { return _hrs.length(); }
977 // The max number of regions in the heap.
978 size_t max_regions() { return _hrs.max_length(); }
980 // The number of regions that are completely free.
981 size_t free_regions() { return _free_list.length(); }
983 // The number of regions that are not completely free.
984 size_t used_regions() { return n_regions() - free_regions(); }
986 // The number of regions available for "regular" expansion.
987 size_t expansion_regions() { return _expansion_regions; }
989 // Factory method for HeapRegion instances. It will return NULL if
990 // the allocation fails.
991 HeapRegion* new_heap_region(size_t hrs_index, HeapWord* bottom);
993 void verify_not_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
994 void verify_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
995 void verify_dirty_young_list(HeapRegion* head) PRODUCT_RETURN;
996 void verify_dirty_young_regions() PRODUCT_RETURN;
998 // verify_region_sets() performs verification over the region
999 // lists. It will be compiled in the product code to be used when
1000 // necessary (i.e., during heap verification).
1001 void verify_region_sets();
1003 // verify_region_sets_optional() is planted in the code for
1004 // list verification in non-product builds (and it can be enabled in
1005 // product builds by definning HEAP_REGION_SET_FORCE_VERIFY to be 1).
1006 #if HEAP_REGION_SET_FORCE_VERIFY
1007 void verify_region_sets_optional() {
1008 verify_region_sets();
1009 }
1010 #else // HEAP_REGION_SET_FORCE_VERIFY
1011 void verify_region_sets_optional() { }
1012 #endif // HEAP_REGION_SET_FORCE_VERIFY
1014 #ifdef ASSERT
1015 bool is_on_master_free_list(HeapRegion* hr) {
1016 return hr->containing_set() == &_free_list;
1017 }
1019 bool is_in_humongous_set(HeapRegion* hr) {
1020 return hr->containing_set() == &_humongous_set;
1021 }
1022 #endif // ASSERT
1024 // Wrapper for the region list operations that can be called from
1025 // methods outside this class.
1027 void secondary_free_list_add_as_tail(FreeRegionList* list) {
1028 _secondary_free_list.add_as_tail(list);
1029 }
1031 void append_secondary_free_list() {
1032 _free_list.add_as_head(&_secondary_free_list);
1033 }
1035 void append_secondary_free_list_if_not_empty_with_lock() {
1036 // If the secondary free list looks empty there's no reason to
1037 // take the lock and then try to append it.
1038 if (!_secondary_free_list.is_empty()) {
1039 MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
1040 append_secondary_free_list();
1041 }
1042 }
1044 void set_free_regions_coming();
1045 void reset_free_regions_coming();
1046 bool free_regions_coming() { return _free_regions_coming; }
1047 void wait_while_free_regions_coming();
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);
1054 // The same as above but assume that the caller holds the Heap_lock.
1055 void collect_locked(GCCause::Cause cause);
1057 // This interface assumes that it's being called by the
1058 // vm thread. It collects the heap assuming that the
1059 // heap lock is already held and that we are executing in
1060 // the context of the vm thread.
1061 virtual void collect_as_vm_thread(GCCause::Cause cause);
1063 // True iff a evacuation has failed in the most-recent collection.
1064 bool evacuation_failed() { return _evacuation_failed; }
1066 // It will free a region if it has allocated objects in it that are
1067 // all dead. It calls either free_region() or
1068 // free_humongous_region() depending on the type of the region that
1069 // is passed to it.
1070 void free_region_if_empty(HeapRegion* hr,
1071 size_t* pre_used,
1072 FreeRegionList* free_list,
1073 HumongousRegionSet* humongous_proxy_set,
1074 HRRSCleanupTask* hrrs_cleanup_task,
1075 bool par);
1077 // It appends the free list to the master free list and updates the
1078 // master humongous list according to the contents of the proxy
1079 // list. It also adjusts the total used bytes according to pre_used
1080 // (if par is true, it will do so by taking the ParGCRareEvent_lock).
1081 void update_sets_after_freeing_regions(size_t pre_used,
1082 FreeRegionList* free_list,
1083 HumongousRegionSet* humongous_proxy_set,
1084 bool par);
1086 // Returns "TRUE" iff "p" points into the allocated area of the heap.
1087 virtual bool is_in(const void* p) const;
1089 // Return "TRUE" iff the given object address is within the collection
1090 // set.
1091 inline bool obj_in_cs(oop obj);
1093 // Return "TRUE" iff the given object address is in the reserved
1094 // region of g1 (excluding the permanent generation).
1095 bool is_in_g1_reserved(const void* p) const {
1096 return _g1_reserved.contains(p);
1097 }
1099 // Returns a MemRegion that corresponds to the space that has been
1100 // reserved for the heap
1101 MemRegion g1_reserved() {
1102 return _g1_reserved;
1103 }
1105 // Returns a MemRegion that corresponds to the space that has been
1106 // committed in the heap
1107 MemRegion g1_committed() {
1108 return _g1_committed;
1109 }
1111 virtual bool is_in_closed_subset(const void* p) const;
1113 // Dirty card table entries covering a list of young regions.
1114 void dirtyCardsForYoungRegions(CardTableModRefBS* ct_bs, HeapRegion* list);
1116 // This resets the card table to all zeros. It is used after
1117 // a collection pause which used the card table to claim cards.
1118 void cleanUpCardTable();
1120 // Iteration functions.
1122 // Iterate over all the ref-containing fields of all objects, calling
1123 // "cl.do_oop" on each.
1124 virtual void oop_iterate(OopClosure* cl) {
1125 oop_iterate(cl, true);
1126 }
1127 void oop_iterate(OopClosure* cl, bool do_perm);
1129 // Same as above, restricted to a memory region.
1130 virtual void oop_iterate(MemRegion mr, OopClosure* cl) {
1131 oop_iterate(mr, cl, true);
1132 }
1133 void oop_iterate(MemRegion mr, OopClosure* cl, bool do_perm);
1135 // Iterate over all objects, calling "cl.do_object" on each.
1136 virtual void object_iterate(ObjectClosure* cl) {
1137 object_iterate(cl, true);
1138 }
1139 virtual void safe_object_iterate(ObjectClosure* cl) {
1140 object_iterate(cl, true);
1141 }
1142 void object_iterate(ObjectClosure* cl, bool do_perm);
1144 // Iterate over all objects allocated since the last collection, calling
1145 // "cl.do_object" on each. The heap must have been initialized properly
1146 // to support this function, or else this call will fail.
1147 virtual void object_iterate_since_last_GC(ObjectClosure* cl);
1149 // Iterate over all spaces in use in the heap, in ascending address order.
1150 virtual void space_iterate(SpaceClosure* cl);
1152 // Iterate over heap regions, in address order, terminating the
1153 // iteration early if the "doHeapRegion" method returns "true".
1154 void heap_region_iterate(HeapRegionClosure* blk) const;
1156 // Iterate over heap regions starting with r (or the first region if "r"
1157 // is NULL), in address order, terminating early if the "doHeapRegion"
1158 // method returns "true".
1159 void heap_region_iterate_from(HeapRegion* r, HeapRegionClosure* blk) const;
1161 // Return the region with the given index. It assumes the index is valid.
1162 HeapRegion* region_at(size_t index) const { return _hrs.at(index); }
1164 // Divide the heap region sequence into "chunks" of some size (the number
1165 // of regions divided by the number of parallel threads times some
1166 // overpartition factor, currently 4). Assumes that this will be called
1167 // in parallel by ParallelGCThreads worker threads with discinct worker
1168 // ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel
1169 // calls will use the same "claim_value", and that that claim value is
1170 // different from the claim_value of any heap region before the start of
1171 // the iteration. Applies "blk->doHeapRegion" to each of the regions, by
1172 // attempting to claim the first region in each chunk, and, if
1173 // successful, applying the closure to each region in the chunk (and
1174 // setting the claim value of the second and subsequent regions of the
1175 // chunk.) For now requires that "doHeapRegion" always returns "false",
1176 // i.e., that a closure never attempt to abort a traversal.
1177 void heap_region_par_iterate_chunked(HeapRegionClosure* blk,
1178 int worker,
1179 jint claim_value);
1181 // It resets all the region claim values to the default.
1182 void reset_heap_region_claim_values();
1184 #ifdef ASSERT
1185 bool check_heap_region_claim_values(jint claim_value);
1186 #endif // ASSERT
1188 // Iterate over the regions (if any) in the current collection set.
1189 void collection_set_iterate(HeapRegionClosure* blk);
1191 // As above but starting from region r
1192 void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk);
1194 // Returns the first (lowest address) compactible space in the heap.
1195 virtual CompactibleSpace* first_compactible_space();
1197 // A CollectedHeap will contain some number of spaces. This finds the
1198 // space containing a given address, or else returns NULL.
1199 virtual Space* space_containing(const void* addr) const;
1201 // A G1CollectedHeap will contain some number of heap regions. This
1202 // finds the region containing a given address, or else returns NULL.
1203 template <class T>
1204 inline HeapRegion* heap_region_containing(const T addr) const;
1206 // Like the above, but requires "addr" to be in the heap (to avoid a
1207 // null-check), and unlike the above, may return an continuing humongous
1208 // region.
1209 template <class T>
1210 inline HeapRegion* heap_region_containing_raw(const T addr) const;
1212 // A CollectedHeap is divided into a dense sequence of "blocks"; that is,
1213 // each address in the (reserved) heap is a member of exactly
1214 // one block. The defining characteristic of a block is that it is
1215 // possible to find its size, and thus to progress forward to the next
1216 // block. (Blocks may be of different sizes.) Thus, blocks may
1217 // represent Java objects, or they might be free blocks in a
1218 // free-list-based heap (or subheap), as long as the two kinds are
1219 // distinguishable and the size of each is determinable.
1221 // Returns the address of the start of the "block" that contains the
1222 // address "addr". We say "blocks" instead of "object" since some heaps
1223 // may not pack objects densely; a chunk may either be an object or a
1224 // non-object.
1225 virtual HeapWord* block_start(const void* addr) const;
1227 // Requires "addr" to be the start of a chunk, and returns its size.
1228 // "addr + size" is required to be the start of a new chunk, or the end
1229 // of the active area of the heap.
1230 virtual size_t block_size(const HeapWord* addr) const;
1232 // Requires "addr" to be the start of a block, and returns "TRUE" iff
1233 // the block is an object.
1234 virtual bool block_is_obj(const HeapWord* addr) const;
1236 // Does this heap support heap inspection? (+PrintClassHistogram)
1237 virtual bool supports_heap_inspection() const { return true; }
1239 // Section on thread-local allocation buffers (TLABs)
1240 // See CollectedHeap for semantics.
1242 virtual bool supports_tlab_allocation() const;
1243 virtual size_t tlab_capacity(Thread* thr) const;
1244 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
1246 // Can a compiler initialize a new object without store barriers?
1247 // This permission only extends from the creation of a new object
1248 // via a TLAB up to the first subsequent safepoint. If such permission
1249 // is granted for this heap type, the compiler promises to call
1250 // defer_store_barrier() below on any slow path allocation of
1251 // a new object for which such initializing store barriers will
1252 // have been elided. G1, like CMS, allows this, but should be
1253 // ready to provide a compensating write barrier as necessary
1254 // if that storage came out of a non-young region. The efficiency
1255 // of this implementation depends crucially on being able to
1256 // answer very efficiently in constant time whether a piece of
1257 // storage in the heap comes from a young region or not.
1258 // See ReduceInitialCardMarks.
1259 virtual bool can_elide_tlab_store_barriers() const {
1260 // 6920090: Temporarily disabled, because of lingering
1261 // instabilities related to RICM with G1. In the
1262 // interim, the option ReduceInitialCardMarksForG1
1263 // below is left solely as a debugging device at least
1264 // until 6920109 fixes the instabilities.
1265 return ReduceInitialCardMarksForG1;
1266 }
1268 virtual bool card_mark_must_follow_store() const {
1269 return true;
1270 }
1272 bool is_in_young(const oop obj) {
1273 HeapRegion* hr = heap_region_containing(obj);
1274 return hr != NULL && hr->is_young();
1275 }
1277 #ifdef ASSERT
1278 virtual bool is_in_partial_collection(const void* p);
1279 #endif
1281 virtual bool is_scavengable(const void* addr);
1283 // We don't need barriers for initializing stores to objects
1284 // in the young gen: for the SATB pre-barrier, there is no
1285 // pre-value that needs to be remembered; for the remembered-set
1286 // update logging post-barrier, we don't maintain remembered set
1287 // information for young gen objects. Note that non-generational
1288 // G1 does not have any "young" objects, should not elide
1289 // the rs logging barrier and so should always answer false below.
1290 // However, non-generational G1 (-XX:-G1Gen) appears to have
1291 // bit-rotted so was not tested below.
1292 virtual bool can_elide_initializing_store_barrier(oop new_obj) {
1293 // Re 6920090, 6920109 above.
1294 assert(ReduceInitialCardMarksForG1, "Else cannot be here");
1295 assert(G1Gen || !is_in_young(new_obj),
1296 "Non-generational G1 should never return true below");
1297 return is_in_young(new_obj);
1298 }
1300 // Can a compiler elide a store barrier when it writes
1301 // a permanent oop into the heap? Applies when the compiler
1302 // is storing x to the heap, where x->is_perm() is true.
1303 virtual bool can_elide_permanent_oop_store_barriers() const {
1304 // At least until perm gen collection is also G1-ified, at
1305 // which point this should return false.
1306 return true;
1307 }
1309 // Returns "true" iff the given word_size is "very large".
1310 static bool isHumongous(size_t word_size) {
1311 // Note this has to be strictly greater-than as the TLABs
1312 // are capped at the humongous thresold and we want to
1313 // ensure that we don't try to allocate a TLAB as
1314 // humongous and that we don't allocate a humongous
1315 // object in a TLAB.
1316 return word_size > _humongous_object_threshold_in_words;
1317 }
1319 // Update mod union table with the set of dirty cards.
1320 void updateModUnion();
1322 // Set the mod union bits corresponding to the given memRegion. Note
1323 // that this is always a safe operation, since it doesn't clear any
1324 // bits.
1325 void markModUnionRange(MemRegion mr);
1327 // Records the fact that a marking phase is no longer in progress.
1328 void set_marking_complete() {
1329 _mark_in_progress = false;
1330 }
1331 void set_marking_started() {
1332 _mark_in_progress = true;
1333 }
1334 bool mark_in_progress() {
1335 return _mark_in_progress;
1336 }
1338 // Print the maximum heap capacity.
1339 virtual size_t max_capacity() const;
1341 virtual jlong millis_since_last_gc();
1343 // Perform any cleanup actions necessary before allowing a verification.
1344 virtual void prepare_for_verify();
1346 // Perform verification.
1348 // vo == UsePrevMarking -> use "prev" marking information,
1349 // vo == UseNextMarking -> use "next" marking information
1350 // vo == UseMarkWord -> use the mark word in the object header
1351 //
1352 // NOTE: Only the "prev" marking information is guaranteed to be
1353 // consistent most of the time, so most calls to this should use
1354 // vo == UsePrevMarking.
1355 // Currently, there is only one case where this is called with
1356 // vo == UseNextMarking, which is to verify the "next" marking
1357 // information at the end of remark.
1358 // Currently there is only one place where this is called with
1359 // vo == UseMarkWord, which is to verify the marking during a
1360 // full GC.
1361 void verify(bool allow_dirty, bool silent, VerifyOption vo);
1363 // Override; it uses the "prev" marking information
1364 virtual void verify(bool allow_dirty, bool silent);
1365 // Default behavior by calling print(tty);
1366 virtual void print() const;
1367 // This calls print_on(st, PrintHeapAtGCExtended).
1368 virtual void print_on(outputStream* st) const;
1369 // If extended is true, it will print out information for all
1370 // regions in the heap by calling print_on_extended(st).
1371 virtual void print_on(outputStream* st, bool extended) const;
1372 virtual void print_on_extended(outputStream* st) const;
1374 virtual void print_gc_threads_on(outputStream* st) const;
1375 virtual void gc_threads_do(ThreadClosure* tc) const;
1377 // Override
1378 void print_tracing_info() const;
1380 // The following two methods are helpful for debugging RSet issues.
1381 void print_cset_rsets() PRODUCT_RETURN;
1382 void print_all_rsets() PRODUCT_RETURN;
1384 // Convenience function to be used in situations where the heap type can be
1385 // asserted to be this type.
1386 static G1CollectedHeap* heap();
1388 void empty_young_list();
1390 void set_region_short_lived_locked(HeapRegion* hr);
1391 // add appropriate methods for any other surv rate groups
1393 YoungList* young_list() { return _young_list; }
1395 // debugging
1396 bool check_young_list_well_formed() {
1397 return _young_list->check_list_well_formed();
1398 }
1400 bool check_young_list_empty(bool check_heap,
1401 bool check_sample = true);
1403 // *** Stuff related to concurrent marking. It's not clear to me that so
1404 // many of these need to be public.
1406 // The functions below are helper functions that a subclass of
1407 // "CollectedHeap" can use in the implementation of its virtual
1408 // functions.
1409 // This performs a concurrent marking of the live objects in a
1410 // bitmap off to the side.
1411 void doConcurrentMark();
1413 // Do a full concurrent marking, synchronously.
1414 void do_sync_mark();
1416 bool isMarkedPrev(oop obj) const;
1417 bool isMarkedNext(oop obj) const;
1419 // vo == UsePrevMarking -> use "prev" marking information,
1420 // vo == UseNextMarking -> use "next" marking information,
1421 // vo == UseMarkWord -> use mark word from object header
1422 bool is_obj_dead_cond(const oop obj,
1423 const HeapRegion* hr,
1424 const VerifyOption vo) const {
1426 switch (vo) {
1427 case VerifyOption_G1UsePrevMarking:
1428 return is_obj_dead(obj, hr);
1429 case VerifyOption_G1UseNextMarking:
1430 return is_obj_ill(obj, hr);
1431 default:
1432 assert(vo == VerifyOption_G1UseMarkWord, "must be");
1433 return !obj->is_gc_marked();
1434 }
1435 }
1437 // Determine if an object is dead, given the object and also
1438 // the region to which the object belongs. An object is dead
1439 // iff a) it was not allocated since the last mark and b) it
1440 // is not marked.
1442 bool is_obj_dead(const oop obj, const HeapRegion* hr) const {
1443 return
1444 !hr->obj_allocated_since_prev_marking(obj) &&
1445 !isMarkedPrev(obj);
1446 }
1448 // This is used when copying an object to survivor space.
1449 // If the object is marked live, then we mark the copy live.
1450 // If the object is allocated since the start of this mark
1451 // cycle, then we mark the copy live.
1452 // If the object has been around since the previous mark
1453 // phase, and hasn't been marked yet during this phase,
1454 // then we don't mark it, we just wait for the
1455 // current marking cycle to get to it.
1457 // This function returns true when an object has been
1458 // around since the previous marking and hasn't yet
1459 // been marked during this marking.
1461 bool is_obj_ill(const oop obj, const HeapRegion* hr) const {
1462 return
1463 !hr->obj_allocated_since_next_marking(obj) &&
1464 !isMarkedNext(obj);
1465 }
1467 // Determine if an object is dead, given only the object itself.
1468 // This will find the region to which the object belongs and
1469 // then call the region version of the same function.
1471 // Added if it is in permanent gen it isn't dead.
1472 // Added if it is NULL it isn't dead.
1474 // vo == UsePrevMarking -> use "prev" marking information,
1475 // vo == UseNextMarking -> use "next" marking information,
1476 // vo == UseMarkWord -> use mark word from object header
1477 bool is_obj_dead_cond(const oop obj,
1478 const VerifyOption vo) const {
1480 switch (vo) {
1481 case VerifyOption_G1UsePrevMarking:
1482 return is_obj_dead(obj);
1483 case VerifyOption_G1UseNextMarking:
1484 return is_obj_ill(obj);
1485 default:
1486 assert(vo == VerifyOption_G1UseMarkWord, "must be");
1487 return !obj->is_gc_marked();
1488 }
1489 }
1491 bool is_obj_dead(const oop obj) const {
1492 const HeapRegion* hr = heap_region_containing(obj);
1493 if (hr == NULL) {
1494 if (Universe::heap()->is_in_permanent(obj))
1495 return false;
1496 else if (obj == NULL) return false;
1497 else return true;
1498 }
1499 else return is_obj_dead(obj, hr);
1500 }
1502 bool is_obj_ill(const oop obj) const {
1503 const HeapRegion* hr = heap_region_containing(obj);
1504 if (hr == NULL) {
1505 if (Universe::heap()->is_in_permanent(obj))
1506 return false;
1507 else if (obj == NULL) return false;
1508 else return true;
1509 }
1510 else return is_obj_ill(obj, hr);
1511 }
1513 // The following is just to alert the verification code
1514 // that a full collection has occurred and that the
1515 // remembered sets are no longer up to date.
1516 bool _full_collection;
1517 void set_full_collection() { _full_collection = true;}
1518 void clear_full_collection() {_full_collection = false;}
1519 bool full_collection() {return _full_collection;}
1521 ConcurrentMark* concurrent_mark() const { return _cm; }
1522 ConcurrentG1Refine* concurrent_g1_refine() const { return _cg1r; }
1524 // The dirty cards region list is used to record a subset of regions
1525 // whose cards need clearing. The list if populated during the
1526 // remembered set scanning and drained during the card table
1527 // cleanup. Although the methods are reentrant, population/draining
1528 // phases must not overlap. For synchronization purposes the last
1529 // element on the list points to itself.
1530 HeapRegion* _dirty_cards_region_list;
1531 void push_dirty_cards_region(HeapRegion* hr);
1532 HeapRegion* pop_dirty_cards_region();
1534 public:
1535 void stop_conc_gc_threads();
1537 // <NEW PREDICTION>
1539 double predict_region_elapsed_time_ms(HeapRegion* hr, bool young);
1540 void check_if_region_is_too_expensive(double predicted_time_ms);
1541 size_t pending_card_num();
1542 size_t max_pending_card_num();
1543 size_t cards_scanned();
1545 // </NEW PREDICTION>
1547 protected:
1548 size_t _max_heap_capacity;
1549 };
1551 #define use_local_bitmaps 1
1552 #define verify_local_bitmaps 0
1553 #define oop_buffer_length 256
1555 #ifndef PRODUCT
1556 class GCLabBitMap;
1557 class GCLabBitMapClosure: public BitMapClosure {
1558 private:
1559 ConcurrentMark* _cm;
1560 GCLabBitMap* _bitmap;
1562 public:
1563 GCLabBitMapClosure(ConcurrentMark* cm,
1564 GCLabBitMap* bitmap) {
1565 _cm = cm;
1566 _bitmap = bitmap;
1567 }
1569 virtual bool do_bit(size_t offset);
1570 };
1571 #endif // !PRODUCT
1573 class GCLabBitMap: public BitMap {
1574 private:
1575 ConcurrentMark* _cm;
1577 int _shifter;
1578 size_t _bitmap_word_covers_words;
1580 // beginning of the heap
1581 HeapWord* _heap_start;
1583 // this is the actual start of the GCLab
1584 HeapWord* _real_start_word;
1586 // this is the actual end of the GCLab
1587 HeapWord* _real_end_word;
1589 // this is the first word, possibly located before the actual start
1590 // of the GCLab, that corresponds to the first bit of the bitmap
1591 HeapWord* _start_word;
1593 // size of a GCLab in words
1594 size_t _gclab_word_size;
1596 static int shifter() {
1597 return MinObjAlignment - 1;
1598 }
1600 // how many heap words does a single bitmap word corresponds to?
1601 static size_t bitmap_word_covers_words() {
1602 return BitsPerWord << shifter();
1603 }
1605 size_t gclab_word_size() const {
1606 return _gclab_word_size;
1607 }
1609 // Calculates actual GCLab size in words
1610 size_t gclab_real_word_size() const {
1611 return bitmap_size_in_bits(pointer_delta(_real_end_word, _start_word))
1612 / BitsPerWord;
1613 }
1615 static size_t bitmap_size_in_bits(size_t gclab_word_size) {
1616 size_t bits_in_bitmap = gclab_word_size >> shifter();
1617 // We are going to ensure that the beginning of a word in this
1618 // bitmap also corresponds to the beginning of a word in the
1619 // global marking bitmap. To handle the case where a GCLab
1620 // starts from the middle of the bitmap, we need to add enough
1621 // space (i.e. up to a bitmap word) to ensure that we have
1622 // enough bits in the bitmap.
1623 return bits_in_bitmap + BitsPerWord - 1;
1624 }
1625 public:
1626 GCLabBitMap(HeapWord* heap_start, size_t gclab_word_size)
1627 : BitMap(bitmap_size_in_bits(gclab_word_size)),
1628 _cm(G1CollectedHeap::heap()->concurrent_mark()),
1629 _shifter(shifter()),
1630 _bitmap_word_covers_words(bitmap_word_covers_words()),
1631 _heap_start(heap_start),
1632 _gclab_word_size(gclab_word_size),
1633 _real_start_word(NULL),
1634 _real_end_word(NULL),
1635 _start_word(NULL)
1636 {
1637 guarantee( size_in_words() >= bitmap_size_in_words(),
1638 "just making sure");
1639 }
1641 inline unsigned heapWordToOffset(HeapWord* addr) {
1642 unsigned offset = (unsigned) pointer_delta(addr, _start_word) >> _shifter;
1643 assert(offset < size(), "offset should be within bounds");
1644 return offset;
1645 }
1647 inline HeapWord* offsetToHeapWord(size_t offset) {
1648 HeapWord* addr = _start_word + (offset << _shifter);
1649 assert(_real_start_word <= addr && addr < _real_end_word, "invariant");
1650 return addr;
1651 }
1653 bool fields_well_formed() {
1654 bool ret1 = (_real_start_word == NULL) &&
1655 (_real_end_word == NULL) &&
1656 (_start_word == NULL);
1657 if (ret1)
1658 return true;
1660 bool ret2 = _real_start_word >= _start_word &&
1661 _start_word < _real_end_word &&
1662 (_real_start_word + _gclab_word_size) == _real_end_word &&
1663 (_start_word + _gclab_word_size + _bitmap_word_covers_words)
1664 > _real_end_word;
1665 return ret2;
1666 }
1668 inline bool mark(HeapWord* addr) {
1669 guarantee(use_local_bitmaps, "invariant");
1670 assert(fields_well_formed(), "invariant");
1672 if (addr >= _real_start_word && addr < _real_end_word) {
1673 assert(!isMarked(addr), "should not have already been marked");
1675 // first mark it on the bitmap
1676 at_put(heapWordToOffset(addr), true);
1678 return true;
1679 } else {
1680 return false;
1681 }
1682 }
1684 inline bool isMarked(HeapWord* addr) {
1685 guarantee(use_local_bitmaps, "invariant");
1686 assert(fields_well_formed(), "invariant");
1688 return at(heapWordToOffset(addr));
1689 }
1691 void set_buffer(HeapWord* start) {
1692 guarantee(use_local_bitmaps, "invariant");
1693 clear();
1695 assert(start != NULL, "invariant");
1696 _real_start_word = start;
1697 _real_end_word = start + _gclab_word_size;
1699 size_t diff =
1700 pointer_delta(start, _heap_start) % _bitmap_word_covers_words;
1701 _start_word = start - diff;
1703 assert(fields_well_formed(), "invariant");
1704 }
1706 #ifndef PRODUCT
1707 void verify() {
1708 // verify that the marks have been propagated
1709 GCLabBitMapClosure cl(_cm, this);
1710 iterate(&cl);
1711 }
1712 #endif // PRODUCT
1714 void retire() {
1715 guarantee(use_local_bitmaps, "invariant");
1716 assert(fields_well_formed(), "invariant");
1718 if (_start_word != NULL) {
1719 CMBitMap* mark_bitmap = _cm->nextMarkBitMap();
1721 // this means that the bitmap was set up for the GCLab
1722 assert(_real_start_word != NULL && _real_end_word != NULL, "invariant");
1724 mark_bitmap->mostly_disjoint_range_union(this,
1725 0, // always start from the start of the bitmap
1726 _start_word,
1727 gclab_real_word_size());
1728 _cm->grayRegionIfNecessary(MemRegion(_real_start_word, _real_end_word));
1730 #ifndef PRODUCT
1731 if (use_local_bitmaps && verify_local_bitmaps)
1732 verify();
1733 #endif // PRODUCT
1734 } else {
1735 assert(_real_start_word == NULL && _real_end_word == NULL, "invariant");
1736 }
1737 }
1739 size_t bitmap_size_in_words() const {
1740 return (bitmap_size_in_bits(gclab_word_size()) + BitsPerWord - 1) / BitsPerWord;
1741 }
1743 };
1745 class G1ParGCAllocBuffer: public ParGCAllocBuffer {
1746 private:
1747 bool _retired;
1748 bool _during_marking;
1749 GCLabBitMap _bitmap;
1751 public:
1752 G1ParGCAllocBuffer(size_t gclab_word_size) :
1753 ParGCAllocBuffer(gclab_word_size),
1754 _during_marking(G1CollectedHeap::heap()->mark_in_progress()),
1755 _bitmap(G1CollectedHeap::heap()->reserved_region().start(), gclab_word_size),
1756 _retired(false)
1757 { }
1759 inline bool mark(HeapWord* addr) {
1760 guarantee(use_local_bitmaps, "invariant");
1761 assert(_during_marking, "invariant");
1762 return _bitmap.mark(addr);
1763 }
1765 inline void set_buf(HeapWord* buf) {
1766 if (use_local_bitmaps && _during_marking)
1767 _bitmap.set_buffer(buf);
1768 ParGCAllocBuffer::set_buf(buf);
1769 _retired = false;
1770 }
1772 inline void retire(bool end_of_gc, bool retain) {
1773 if (_retired)
1774 return;
1775 if (use_local_bitmaps && _during_marking) {
1776 _bitmap.retire();
1777 }
1778 ParGCAllocBuffer::retire(end_of_gc, retain);
1779 _retired = true;
1780 }
1781 };
1783 class G1ParScanThreadState : public StackObj {
1784 protected:
1785 G1CollectedHeap* _g1h;
1786 RefToScanQueue* _refs;
1787 DirtyCardQueue _dcq;
1788 CardTableModRefBS* _ct_bs;
1789 G1RemSet* _g1_rem;
1791 G1ParGCAllocBuffer _surviving_alloc_buffer;
1792 G1ParGCAllocBuffer _tenured_alloc_buffer;
1793 G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount];
1794 ageTable _age_table;
1796 size_t _alloc_buffer_waste;
1797 size_t _undo_waste;
1799 OopsInHeapRegionClosure* _evac_failure_cl;
1800 G1ParScanHeapEvacClosure* _evac_cl;
1801 G1ParScanPartialArrayClosure* _partial_scan_cl;
1803 int _hash_seed;
1804 int _queue_num;
1806 size_t _term_attempts;
1808 double _start;
1809 double _start_strong_roots;
1810 double _strong_roots_time;
1811 double _start_term;
1812 double _term_time;
1814 // Map from young-age-index (0 == not young, 1 is youngest) to
1815 // surviving words. base is what we get back from the malloc call
1816 size_t* _surviving_young_words_base;
1817 // this points into the array, as we use the first few entries for padding
1818 size_t* _surviving_young_words;
1820 #define PADDING_ELEM_NUM (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t))
1822 void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
1824 void add_to_undo_waste(size_t waste) { _undo_waste += waste; }
1826 DirtyCardQueue& dirty_card_queue() { return _dcq; }
1827 CardTableModRefBS* ctbs() { return _ct_bs; }
1829 template <class T> void immediate_rs_update(HeapRegion* from, T* p, int tid) {
1830 if (!from->is_survivor()) {
1831 _g1_rem->par_write_ref(from, p, tid);
1832 }
1833 }
1835 template <class T> void deferred_rs_update(HeapRegion* from, T* p, int tid) {
1836 // If the new value of the field points to the same region or
1837 // is the to-space, we don't need to include it in the Rset updates.
1838 if (!from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) && !from->is_survivor()) {
1839 size_t card_index = ctbs()->index_for(p);
1840 // If the card hasn't been added to the buffer, do it.
1841 if (ctbs()->mark_card_deferred(card_index)) {
1842 dirty_card_queue().enqueue((jbyte*)ctbs()->byte_for_index(card_index));
1843 }
1844 }
1845 }
1847 public:
1848 G1ParScanThreadState(G1CollectedHeap* g1h, int queue_num);
1850 ~G1ParScanThreadState() {
1851 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base);
1852 }
1854 RefToScanQueue* refs() { return _refs; }
1855 ageTable* age_table() { return &_age_table; }
1857 G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) {
1858 return _alloc_buffers[purpose];
1859 }
1861 size_t alloc_buffer_waste() const { return _alloc_buffer_waste; }
1862 size_t undo_waste() const { return _undo_waste; }
1864 #ifdef ASSERT
1865 bool verify_ref(narrowOop* ref) const;
1866 bool verify_ref(oop* ref) const;
1867 bool verify_task(StarTask ref) const;
1868 #endif // ASSERT
1870 template <class T> void push_on_queue(T* ref) {
1871 assert(verify_ref(ref), "sanity");
1872 refs()->push(ref);
1873 }
1875 template <class T> void update_rs(HeapRegion* from, T* p, int tid) {
1876 if (G1DeferredRSUpdate) {
1877 deferred_rs_update(from, p, tid);
1878 } else {
1879 immediate_rs_update(from, p, tid);
1880 }
1881 }
1883 HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz) {
1885 HeapWord* obj = NULL;
1886 size_t gclab_word_size = _g1h->desired_plab_sz(purpose);
1887 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
1888 G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose);
1889 assert(gclab_word_size == alloc_buf->word_sz(),
1890 "dynamic resizing is not supported");
1891 add_to_alloc_buffer_waste(alloc_buf->words_remaining());
1892 alloc_buf->retire(false, false);
1894 HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size);
1895 if (buf == NULL) return NULL; // Let caller handle allocation failure.
1896 // Otherwise.
1897 alloc_buf->set_buf(buf);
1899 obj = alloc_buf->allocate(word_sz);
1900 assert(obj != NULL, "buffer was definitely big enough...");
1901 } else {
1902 obj = _g1h->par_allocate_during_gc(purpose, word_sz);
1903 }
1904 return obj;
1905 }
1907 HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz) {
1908 HeapWord* obj = alloc_buffer(purpose)->allocate(word_sz);
1909 if (obj != NULL) return obj;
1910 return allocate_slow(purpose, word_sz);
1911 }
1913 void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz) {
1914 if (alloc_buffer(purpose)->contains(obj)) {
1915 assert(alloc_buffer(purpose)->contains(obj + word_sz - 1),
1916 "should contain whole object");
1917 alloc_buffer(purpose)->undo_allocation(obj, word_sz);
1918 } else {
1919 CollectedHeap::fill_with_object(obj, word_sz);
1920 add_to_undo_waste(word_sz);
1921 }
1922 }
1924 void set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_cl) {
1925 _evac_failure_cl = evac_failure_cl;
1926 }
1927 OopsInHeapRegionClosure* evac_failure_closure() {
1928 return _evac_failure_cl;
1929 }
1931 void set_evac_closure(G1ParScanHeapEvacClosure* evac_cl) {
1932 _evac_cl = evac_cl;
1933 }
1935 void set_partial_scan_closure(G1ParScanPartialArrayClosure* partial_scan_cl) {
1936 _partial_scan_cl = partial_scan_cl;
1937 }
1939 int* hash_seed() { return &_hash_seed; }
1940 int queue_num() { return _queue_num; }
1942 size_t term_attempts() const { return _term_attempts; }
1943 void note_term_attempt() { _term_attempts++; }
1945 void start_strong_roots() {
1946 _start_strong_roots = os::elapsedTime();
1947 }
1948 void end_strong_roots() {
1949 _strong_roots_time += (os::elapsedTime() - _start_strong_roots);
1950 }
1951 double strong_roots_time() const { return _strong_roots_time; }
1953 void start_term_time() {
1954 note_term_attempt();
1955 _start_term = os::elapsedTime();
1956 }
1957 void end_term_time() {
1958 _term_time += (os::elapsedTime() - _start_term);
1959 }
1960 double term_time() const { return _term_time; }
1962 double elapsed_time() const {
1963 return os::elapsedTime() - _start;
1964 }
1966 static void
1967 print_termination_stats_hdr(outputStream* const st = gclog_or_tty);
1968 void
1969 print_termination_stats(int i, outputStream* const st = gclog_or_tty) const;
1971 size_t* surviving_young_words() {
1972 // We add on to hide entry 0 which accumulates surviving words for
1973 // age -1 regions (i.e. non-young ones)
1974 return _surviving_young_words;
1975 }
1977 void retire_alloc_buffers() {
1978 for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
1979 size_t waste = _alloc_buffers[ap]->words_remaining();
1980 add_to_alloc_buffer_waste(waste);
1981 _alloc_buffers[ap]->retire(true, false);
1982 }
1983 }
1985 template <class T> void deal_with_reference(T* ref_to_scan) {
1986 if (has_partial_array_mask(ref_to_scan)) {
1987 _partial_scan_cl->do_oop_nv(ref_to_scan);
1988 } else {
1989 // Note: we can use "raw" versions of "region_containing" because
1990 // "obj_to_scan" is definitely in the heap, and is not in a
1991 // humongous region.
1992 HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
1993 _evac_cl->set_region(r);
1994 _evac_cl->do_oop_nv(ref_to_scan);
1995 }
1996 }
1998 void deal_with_reference(StarTask ref) {
1999 assert(verify_task(ref), "sanity");
2000 if (ref.is_narrow()) {
2001 deal_with_reference((narrowOop*)ref);
2002 } else {
2003 deal_with_reference((oop*)ref);
2004 }
2005 }
2007 public:
2008 void trim_queue();
2009 };
2011 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP