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
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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
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24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
27
28 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
29 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
30 #include "gc_implementation/g1/survRateGroup.hpp"
31 #include "gc_implementation/shared/ageTable.hpp"
32 #include "gc_implementation/shared/spaceDecorator.hpp"
33 #include "memory/space.inline.hpp"
34 #include "memory/watermark.hpp"
35 #include "utilities/macros.hpp"
36
37 #if INCLUDE_ALL_GCS
38
39 // A HeapRegion is the smallest piece of a G1CollectedHeap that
40 // can be collected independently.
41
42 // NOTE: Although a HeapRegion is a Space, its
43 // Space::initDirtyCardClosure method must not be called.
44 // The problem is that the existence of this method breaks
45 // the independence of barrier sets from remembered sets.
46 // The solution is to remove this method from the definition
47 // of a Space.
48
49 class CompactibleSpace;
50 class ContiguousSpace;
51 class HeapRegionRemSet;
52 class HeapRegionRemSetIterator;
53 class HeapRegion;
54 class HeapRegionSetBase;
55
56 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
57 #define HR_FORMAT_PARAMS(_hr_) \
58 (_hr_)->hrs_index(), \
59 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \
60 (_hr_)->startsHumongous() ? "HS" : \
61 (_hr_)->continuesHumongous() ? "HC" : \
62 !(_hr_)->is_empty() ? "O" : "F", \
63 (_hr_)->bottom(), (_hr_)->top(), (_hr_)->end()
64
65 // sentinel value for hrs_index
66 #define G1_NULL_HRS_INDEX ((uint) -1)
67
68 // A dirty card to oop closure for heap regions. It
69 // knows how to get the G1 heap and how to use the bitmap
70 // in the concurrent marker used by G1 to filter remembered
71 // sets.
72
73 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
74 public:
75 // Specification of possible DirtyCardToOopClosure filtering.
76 enum FilterKind {
77 NoFilterKind,
78 IntoCSFilterKind,
79 OutOfRegionFilterKind
80 };
81
82 protected:
83 HeapRegion* _hr;
84 FilterKind _fk;
85 G1CollectedHeap* _g1;
86
87 void walk_mem_region_with_cl(MemRegion mr,
88 HeapWord* bottom, HeapWord* top,
89 ExtendedOopClosure* cl);
90
91 // We don't specialize this for FilteringClosure; filtering is handled by
92 // the "FilterKind" mechanism. But we provide this to avoid a compiler
93 // warning.
94 void walk_mem_region_with_cl(MemRegion mr,
95 HeapWord* bottom, HeapWord* top,
96 FilteringClosure* cl) {
97 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
98 (ExtendedOopClosure*)cl);
99 }
100
101 // Get the actual top of the area on which the closure will
102 // operate, given where the top is assumed to be (the end of the
103 // memory region passed to do_MemRegion) and where the object
104 // at the top is assumed to start. For example, an object may
105 // start at the top but actually extend past the assumed top,
106 // in which case the top becomes the end of the object.
107 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
108 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
109 }
110
111 // Walk the given memory region from bottom to (actual) top
112 // looking for objects and applying the oop closure (_cl) to
113 // them. The base implementation of this treats the area as
114 // blocks, where a block may or may not be an object. Sub-
115 // classes should override this to provide more accurate
116 // or possibly more efficient walking.
117 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) {
118 Filtering_DCTOC::walk_mem_region(mr, bottom, top);
119 }
120
121 public:
122 HeapRegionDCTOC(G1CollectedHeap* g1,
123 HeapRegion* hr, ExtendedOopClosure* cl,
124 CardTableModRefBS::PrecisionStyle precision,
125 FilterKind fk);
126 };
127
128 // The complicating factor is that BlockOffsetTable diverged
129 // significantly, and we need functionality that is only in the G1 version.
130 // So I copied that code, which led to an alternate G1 version of
131 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
132 // be reconciled, then G1OffsetTableContigSpace could go away.
133
134 // The idea behind time stamps is the following. Doing a save_marks on
135 // all regions at every GC pause is time consuming (if I remember
136 // well, 10ms or so). So, we would like to do that only for regions
137 // that are GC alloc regions. To achieve this, we use time
138 // stamps. For every evacuation pause, G1CollectedHeap generates a
139 // unique time stamp (essentially a counter that gets
140 // incremented). Every time we want to call save_marks on a region,
141 // we set the saved_mark_word to top and also copy the current GC
142 // time stamp to the time stamp field of the space. Reading the
143 // saved_mark_word involves checking the time stamp of the
144 // region. If it is the same as the current GC time stamp, then we
145 // can safely read the saved_mark_word field, as it is valid. If the
146 // time stamp of the region is not the same as the current GC time
147 // stamp, then we instead read top, as the saved_mark_word field is
148 // invalid. Time stamps (on the regions and also on the
149 // G1CollectedHeap) are reset at every cleanup (we iterate over
150 // the regions anyway) and at the end of a Full GC. The current scheme
151 // that uses sequential unsigned ints will fail only if we have 4b
152 // evacuation pauses between two cleanups, which is _highly_ unlikely.
153
154 class G1OffsetTableContigSpace: public ContiguousSpace {
155 friend class VMStructs;
156 protected:
157 G1BlockOffsetArrayContigSpace _offsets;
158 Mutex _par_alloc_lock;
159 volatile unsigned _gc_time_stamp;
160 // When we need to retire an allocation region, while other threads
161 // are also concurrently trying to allocate into it, we typically
162 // allocate a dummy object at the end of the region to ensure that
163 // no more allocations can take place in it. However, sometimes we
164 // want to know where the end of the last "real" object we allocated
165 // into the region was and this is what this keeps track.
166 HeapWord* _pre_dummy_top;
167
168 public:
169 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
170 MemRegion mr);
171
172 void set_bottom(HeapWord* value);
173 void set_end(HeapWord* value);
174
175 virtual HeapWord* saved_mark_word() const;
176 virtual void set_saved_mark();
177 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
178 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
179
180 // See the comment above in the declaration of _pre_dummy_top for an
181 // explanation of what it is.
182 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
183 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
184 _pre_dummy_top = pre_dummy_top;
185 }
186 HeapWord* pre_dummy_top() {
187 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
188 }
189 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
190
191 virtual void clear(bool mangle_space);
192
193 HeapWord* block_start(const void* p);
194 HeapWord* block_start_const(const void* p) const;
195
196 // Add offset table update.
197 virtual HeapWord* allocate(size_t word_size);
198 HeapWord* par_allocate(size_t word_size);
199
200 // MarkSweep support phase3
201 virtual HeapWord* initialize_threshold();
202 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
203
204 virtual void print() const;
205
206 void reset_bot() {
207 _offsets.zero_bottom_entry();
208 _offsets.initialize_threshold();
209 }
210
211 void update_bot_for_object(HeapWord* start, size_t word_size) {
212 _offsets.alloc_block(start, word_size);
213 }
214
215 void print_bot_on(outputStream* out) {
216 _offsets.print_on(out);
217 }
218 };
219
220 class HeapRegion: public G1OffsetTableContigSpace {
221 friend class VMStructs;
222 private:
223
224 enum HumongousType {
225 NotHumongous = 0,
226 StartsHumongous,
227 ContinuesHumongous
228 };
229
230 // Requires that the region "mr" be dense with objects, and begin and end
231 // with an object.
232 void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl);
233
234 // The remembered set for this region.
235 // (Might want to make this "inline" later, to avoid some alloc failure
236 // issues.)
237 HeapRegionRemSet* _rem_set;
238
239 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
240
241 protected:
242 // The index of this region in the heap region sequence.
243 uint _hrs_index;
244
245 HumongousType _humongous_type;
246 // For a humongous region, region in which it starts.
247 HeapRegion* _humongous_start_region;
248 // For the start region of a humongous sequence, it's original end().
249 HeapWord* _orig_end;
250
251 // True iff the region is in current collection_set.
252 bool _in_collection_set;
253
254 // True iff an attempt to evacuate an object in the region failed.
255 bool _evacuation_failed;
256
257 // A heap region may be a member one of a number of special subsets, each
258 // represented as linked lists through the field below. Currently, these
259 // sets include:
260 // The collection set.
261 // The set of allocation regions used in a collection pause.
262 // Spaces that may contain gray objects.
263 HeapRegion* _next_in_special_set;
264
265 // next region in the young "generation" region set
266 HeapRegion* _next_young_region;
267
268 // Next region whose cards need cleaning
269 HeapRegion* _next_dirty_cards_region;
270
271 // Fields used by the HeapRegionSetBase class and subclasses.
272 HeapRegion* _next;
273 #ifdef ASSERT
274 HeapRegionSetBase* _containing_set;
275 #endif // ASSERT
276 bool _pending_removal;
277
278 // For parallel heapRegion traversal.
279 jint _claimed;
280
281 // We use concurrent marking to determine the amount of live data
282 // in each heap region.
283 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
284 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
285
286 // The calculated GC efficiency of the region.
287 double _gc_efficiency;
288
289 enum YoungType {
290 NotYoung, // a region is not young
291 Young, // a region is young
292 Survivor // a region is young and it contains survivors
293 };
294
295 volatile YoungType _young_type;
296 int _young_index_in_cset;
297 SurvRateGroup* _surv_rate_group;
298 int _age_index;
299
300 // The start of the unmarked area. The unmarked area extends from this
301 // word until the top and/or end of the region, and is the part
302 // of the region for which no marking was done, i.e. objects may
303 // have been allocated in this part since the last mark phase.
304 // "prev" is the top at the start of the last completed marking.
305 // "next" is the top at the start of the in-progress marking (if any.)
306 HeapWord* _prev_top_at_mark_start;
307 HeapWord* _next_top_at_mark_start;
308 // If a collection pause is in progress, this is the top at the start
309 // of that pause.
310
311 void init_top_at_mark_start() {
312 assert(_prev_marked_bytes == 0 &&
313 _next_marked_bytes == 0,
314 "Must be called after zero_marked_bytes.");
315 HeapWord* bot = bottom();
316 _prev_top_at_mark_start = bot;
317 _next_top_at_mark_start = bot;
318 }
319
320 void set_young_type(YoungType new_type) {
321 //assert(_young_type != new_type, "setting the same type" );
322 // TODO: add more assertions here
323 _young_type = new_type;
324 }
325
326 // Cached attributes used in the collection set policy information
327
328 // The RSet length that was added to the total value
329 // for the collection set.
330 size_t _recorded_rs_length;
331
332 // The predicted elapsed time that was added to total value
333 // for the collection set.
334 double _predicted_elapsed_time_ms;
335
336 // The predicted number of bytes to copy that was added to
337 // the total value for the collection set.
338 size_t _predicted_bytes_to_copy;
339
340 public:
341 HeapRegion(uint hrs_index,
342 G1BlockOffsetSharedArray* sharedOffsetArray,
343 MemRegion mr);
344
345 static int LogOfHRGrainBytes;
346 static int LogOfHRGrainWords;
347
348 static size_t GrainBytes;
349 static size_t GrainWords;
350 static size_t CardsPerRegion;
351
352 static size_t align_up_to_region_byte_size(size_t sz) {
353 return (sz + (size_t) GrainBytes - 1) &
354 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
355 }
356
357 // It sets up the heap region size (GrainBytes / GrainWords), as
358 // well as other related fields that are based on the heap region
359 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
360 // CardsPerRegion). All those fields are considered constant
361 // throughout the JVM's execution, therefore they should only be set
362 // up once during initialization time.
363 static void setup_heap_region_size(uintx min_heap_size);
364
365 enum ClaimValues {
366 InitialClaimValue = 0,
367 FinalCountClaimValue = 1,
368 NoteEndClaimValue = 2,
369 ScrubRemSetClaimValue = 3,
370 ParVerifyClaimValue = 4,
371 RebuildRSClaimValue = 5,
372 ParEvacFailureClaimValue = 6,
373 AggregateCountClaimValue = 7,
374 VerifyCountClaimValue = 8
375 };
376
377 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
378 assert(is_young(), "we can only skip BOT updates on young regions");
379 return ContiguousSpace::par_allocate(word_size);
380 }
381 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
382 assert(is_young(), "we can only skip BOT updates on young regions");
383 return ContiguousSpace::allocate(word_size);
384 }
385
386 // If this region is a member of a HeapRegionSeq, the index in that
387 // sequence, otherwise -1.
388 uint hrs_index() const { return _hrs_index; }
389
390 // The number of bytes marked live in the region in the last marking phase.
391 size_t marked_bytes() { return _prev_marked_bytes; }
392 size_t live_bytes() {
393 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
394 }
395
396 // The number of bytes counted in the next marking.
397 size_t next_marked_bytes() { return _next_marked_bytes; }
398 // The number of bytes live wrt the next marking.
399 size_t next_live_bytes() {
400 return
401 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
402 }
403
404 // A lower bound on the amount of garbage bytes in the region.
405 size_t garbage_bytes() {
406 size_t used_at_mark_start_bytes =
407 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
408 assert(used_at_mark_start_bytes >= marked_bytes(),
409 "Can't mark more than we have.");
410 return used_at_mark_start_bytes - marked_bytes();
411 }
412
413 // Return the amount of bytes we'll reclaim if we collect this
414 // region. This includes not only the known garbage bytes in the
415 // region but also any unallocated space in it, i.e., [top, end),
416 // since it will also be reclaimed if we collect the region.
417 size_t reclaimable_bytes() {
418 size_t known_live_bytes = live_bytes();
419 assert(known_live_bytes <= capacity(), "sanity");
420 return capacity() - known_live_bytes;
421 }
422
423 // An upper bound on the number of live bytes in the region.
424 size_t max_live_bytes() { return used() - garbage_bytes(); }
425
426 void add_to_marked_bytes(size_t incr_bytes) {
427 _next_marked_bytes = _next_marked_bytes + incr_bytes;
428 assert(_next_marked_bytes <= used(), "invariant" );
429 }
430
431 void zero_marked_bytes() {
432 _prev_marked_bytes = _next_marked_bytes = 0;
433 }
434
435 bool isHumongous() const { return _humongous_type != NotHumongous; }
436 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
437 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
438 // For a humongous region, region in which it starts.
439 HeapRegion* humongous_start_region() const {
440 return _humongous_start_region;
441 }
442
443 // Return the number of distinct regions that are covered by this region:
444 // 1 if the region is not humongous, >= 1 if the region is humongous.
445 uint region_num() const {
446 if (!isHumongous()) {
447 return 1U;
448 } else {
449 assert(startsHumongous(), "doesn't make sense on HC regions");
450 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
451 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
452 }
453 }
454
455 // Return the index + 1 of the last HC regions that's associated
456 // with this HS region.
457 uint last_hc_index() const {
458 assert(startsHumongous(), "don't call this otherwise");
459 return hrs_index() + region_num();
460 }
461
462 // Same as Space::is_in_reserved, but will use the original size of the region.
463 // The original size is different only for start humongous regions. They get
464 // their _end set up to be the end of the last continues region of the
465 // corresponding humongous object.
466 bool is_in_reserved_raw(const void* p) const {
467 return _bottom <= p && p < _orig_end;
468 }
469
470 // Makes the current region be a "starts humongous" region, i.e.,
471 // the first region in a series of one or more contiguous regions
472 // that will contain a single "humongous" object. The two parameters
473 // are as follows:
474 //
475 // new_top : The new value of the top field of this region which
476 // points to the end of the humongous object that's being
477 // allocated. If there is more than one region in the series, top
478 // will lie beyond this region's original end field and on the last
479 // region in the series.
480 //
481 // new_end : The new value of the end field of this region which
482 // points to the end of the last region in the series. If there is
483 // one region in the series (namely: this one) end will be the same
484 // as the original end of this region.
485 //
486 // Updating top and end as described above makes this region look as
487 // if it spans the entire space taken up by all the regions in the
488 // series and an single allocation moved its top to new_top. This
489 // ensures that the space (capacity / allocated) taken up by all
490 // humongous regions can be calculated by just looking at the
491 // "starts humongous" regions and by ignoring the "continues
492 // humongous" regions.
493 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
494
495 // Makes the current region be a "continues humongous'
496 // region. first_hr is the "start humongous" region of the series
497 // which this region will be part of.
498 void set_continuesHumongous(HeapRegion* first_hr);
499
500 // Unsets the humongous-related fields on the region.
501 void set_notHumongous();
502
503 // If the region has a remembered set, return a pointer to it.
504 HeapRegionRemSet* rem_set() const {
505 return _rem_set;
506 }
507
508 // True iff the region is in current collection_set.
509 bool in_collection_set() const {
510 return _in_collection_set;
511 }
512 void set_in_collection_set(bool b) {
513 _in_collection_set = b;
514 }
515 HeapRegion* next_in_collection_set() {
516 assert(in_collection_set(), "should only invoke on member of CS.");
517 assert(_next_in_special_set == NULL ||
518 _next_in_special_set->in_collection_set(),
519 "Malformed CS.");
520 return _next_in_special_set;
521 }
522 void set_next_in_collection_set(HeapRegion* r) {
523 assert(in_collection_set(), "should only invoke on member of CS.");
524 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
525 _next_in_special_set = r;
526 }
527
528 // Methods used by the HeapRegionSetBase class and subclasses.
529
530 // Getter and setter for the next field used to link regions into
531 // linked lists.
532 HeapRegion* next() { return _next; }
533
534 void set_next(HeapRegion* next) { _next = next; }
535
536 // Every region added to a set is tagged with a reference to that
537 // set. This is used for doing consistency checking to make sure that
538 // the contents of a set are as they should be and it's only
539 // available in non-product builds.
540 #ifdef ASSERT
541 void set_containing_set(HeapRegionSetBase* containing_set) {
542 assert((containing_set == NULL && _containing_set != NULL) ||
543 (containing_set != NULL && _containing_set == NULL),
544 err_msg("containing_set: "PTR_FORMAT" "
545 "_containing_set: "PTR_FORMAT,
546 containing_set, _containing_set));
547
548 _containing_set = containing_set;
549 }
550
551 HeapRegionSetBase* containing_set() { return _containing_set; }
552 #else // ASSERT
553 void set_containing_set(HeapRegionSetBase* containing_set) { }
554
555 // containing_set() is only used in asserts so there's no reason
556 // to provide a dummy version of it.
557 #endif // ASSERT
558
559 // If we want to remove regions from a list in bulk we can simply tag
560 // them with the pending_removal tag and call the
561 // remove_all_pending() method on the list.
562
563 bool pending_removal() { return _pending_removal; }
564
565 void set_pending_removal(bool pending_removal) {
566 if (pending_removal) {
567 assert(!_pending_removal && containing_set() != NULL,
568 "can only set pending removal to true if it's false and "
569 "the region belongs to a region set");
570 } else {
571 assert( _pending_removal && containing_set() == NULL,
572 "can only set pending removal to false if it's true and "
573 "the region does not belong to a region set");
574 }
575
576 _pending_removal = pending_removal;
577 }
578
579 HeapRegion* get_next_young_region() { return _next_young_region; }
580 void set_next_young_region(HeapRegion* hr) {
581 _next_young_region = hr;
582 }
583
584 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
585 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
586 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
587 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
588
589 HeapWord* orig_end() { return _orig_end; }
590
591 // Allows logical separation between objects allocated before and after.
592 void save_marks();
593
594 // Reset HR stuff to default values.
595 void hr_clear(bool par, bool clear_space);
596 void par_clear();
597
598 // Get the start of the unmarked area in this region.
599 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
600 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
601
602 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
603 // allocated in the current region before the last call to "save_mark".
604 void oop_before_save_marks_iterate(ExtendedOopClosure* cl);
605
606 // Note the start or end of marking. This tells the heap region
607 // that the collector is about to start or has finished (concurrently)
608 // marking the heap.
609
610 // Notify the region that concurrent marking is starting. Initialize
611 // all fields related to the next marking info.
612 inline void note_start_of_marking();
613
614 // Notify the region that concurrent marking has finished. Copy the
615 // (now finalized) next marking info fields into the prev marking
616 // info fields.
617 inline void note_end_of_marking();
618
619 // Notify the region that it will be used as to-space during a GC
620 // and we are about to start copying objects into it.
621 inline void note_start_of_copying(bool during_initial_mark);
622
623 // Notify the region that it ceases being to-space during a GC and
624 // we will not copy objects into it any more.
625 inline void note_end_of_copying(bool during_initial_mark);
626
627 // Notify the region that we are about to start processing
628 // self-forwarded objects during evac failure handling.
629 void note_self_forwarding_removal_start(bool during_initial_mark,
630 bool during_conc_mark);
631
632 // Notify the region that we have finished processing self-forwarded
633 // objects during evac failure handling.
634 void note_self_forwarding_removal_end(bool during_initial_mark,
635 bool during_conc_mark,
636 size_t marked_bytes);
637
638 // Returns "false" iff no object in the region was allocated when the
639 // last mark phase ended.
640 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
641
642 void reset_during_compaction() {
643 assert(isHumongous() && startsHumongous(),
644 "should only be called for starts humongous regions");
645
646 zero_marked_bytes();
647 init_top_at_mark_start();
648 }
649
650 void calc_gc_efficiency(void);
651 double gc_efficiency() { return _gc_efficiency;}
652
653 bool is_young() const { return _young_type != NotYoung; }
654 bool is_survivor() const { return _young_type == Survivor; }
655
656 int young_index_in_cset() const { return _young_index_in_cset; }
657 void set_young_index_in_cset(int index) {
658 assert( (index == -1) || is_young(), "pre-condition" );
659 _young_index_in_cset = index;
660 }
661
662 int age_in_surv_rate_group() {
663 assert( _surv_rate_group != NULL, "pre-condition" );
664 assert( _age_index > -1, "pre-condition" );
665 return _surv_rate_group->age_in_group(_age_index);
666 }
667
668 void record_surv_words_in_group(size_t words_survived) {
669 assert( _surv_rate_group != NULL, "pre-condition" );
670 assert( _age_index > -1, "pre-condition" );
671 int age_in_group = age_in_surv_rate_group();
672 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
673 }
674
675 int age_in_surv_rate_group_cond() {
676 if (_surv_rate_group != NULL)
677 return age_in_surv_rate_group();
678 else
679 return -1;
680 }
681
682 SurvRateGroup* surv_rate_group() {
683 return _surv_rate_group;
684 }
685
686 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
687 assert( surv_rate_group != NULL, "pre-condition" );
688 assert( _surv_rate_group == NULL, "pre-condition" );
689 assert( is_young(), "pre-condition" );
690
691 _surv_rate_group = surv_rate_group;
692 _age_index = surv_rate_group->next_age_index();
693 }
694
695 void uninstall_surv_rate_group() {
696 if (_surv_rate_group != NULL) {
697 assert( _age_index > -1, "pre-condition" );
698 assert( is_young(), "pre-condition" );
699
700 _surv_rate_group = NULL;
701 _age_index = -1;
702 } else {
703 assert( _age_index == -1, "pre-condition" );
704 }
705 }
706
707 void set_young() { set_young_type(Young); }
708
709 void set_survivor() { set_young_type(Survivor); }
710
711 void set_not_young() { set_young_type(NotYoung); }
712
713 // Determine if an object has been allocated since the last
714 // mark performed by the collector. This returns true iff the object
715 // is within the unmarked area of the region.
716 bool obj_allocated_since_prev_marking(oop obj) const {
717 return (HeapWord *) obj >= prev_top_at_mark_start();
718 }
719 bool obj_allocated_since_next_marking(oop obj) const {
720 return (HeapWord *) obj >= next_top_at_mark_start();
721 }
722
723 // For parallel heapRegion traversal.
724 bool claimHeapRegion(int claimValue);
725 jint claim_value() { return _claimed; }
726 // Use this carefully: only when you're sure no one is claiming...
727 void set_claim_value(int claimValue) { _claimed = claimValue; }
728
729 // Returns the "evacuation_failed" property of the region.
730 bool evacuation_failed() { return _evacuation_failed; }
731
732 // Sets the "evacuation_failed" property of the region.
733 void set_evacuation_failed(bool b) {
734 _evacuation_failed = b;
735
736 if (b) {
737 _next_marked_bytes = 0;
738 }
739 }
740
741 // Requires that "mr" be entirely within the region.
742 // Apply "cl->do_object" to all objects that intersect with "mr".
743 // If the iteration encounters an unparseable portion of the region,
744 // or if "cl->abort()" is true after a closure application,
745 // terminate the iteration and return the address of the start of the
746 // subregion that isn't done. (The two can be distinguished by querying
747 // "cl->abort()".) Return of "NULL" indicates that the iteration
748 // completed.
749 HeapWord*
750 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
751
752 // filter_young: if true and the region is a young region then we
753 // skip the iteration.
754 // card_ptr: if not NULL, and we decide that the card is not young
755 // and we iterate over it, we'll clean the card before we start the
756 // iteration.
757 HeapWord*
758 oops_on_card_seq_iterate_careful(MemRegion mr,
759 FilterOutOfRegionClosure* cl,
760 bool filter_young,
761 jbyte* card_ptr);
762
763 // A version of block start that is guaranteed to find *some* block
764 // boundary at or before "p", but does not object iteration, and may
765 // therefore be used safely when the heap is unparseable.
766 HeapWord* block_start_careful(const void* p) const {
767 return _offsets.block_start_careful(p);
768 }
769
770 // Requires that "addr" is within the region. Returns the start of the
771 // first ("careful") block that starts at or after "addr", or else the
772 // "end" of the region if there is no such block.
773 HeapWord* next_block_start_careful(HeapWord* addr);
774
775 size_t recorded_rs_length() const { return _recorded_rs_length; }
776 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
777 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
778
779 void set_recorded_rs_length(size_t rs_length) {
780 _recorded_rs_length = rs_length;
781 }
782
783 void set_predicted_elapsed_time_ms(double ms) {
784 _predicted_elapsed_time_ms = ms;
785 }
786
787 void set_predicted_bytes_to_copy(size_t bytes) {
788 _predicted_bytes_to_copy = bytes;
789 }
790
791 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
792 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
793 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
794
795 virtual CompactibleSpace* next_compaction_space() const;
796
797 virtual void reset_after_compaction();
798
799 void print() const;
800 void print_on(outputStream* st) const;
801
802 // vo == UsePrevMarking -> use "prev" marking information,
803 // vo == UseNextMarking -> use "next" marking information
804 // vo == UseMarkWord -> use the mark word in the object header
805 //
806 // NOTE: Only the "prev" marking information is guaranteed to be
807 // consistent most of the time, so most calls to this should use
808 // vo == UsePrevMarking.
809 // Currently, there is only one case where this is called with
810 // vo == UseNextMarking, which is to verify the "next" marking
811 // information at the end of remark.
812 // Currently there is only one place where this is called with
813 // vo == UseMarkWord, which is to verify the marking during a
814 // full GC.
815 void verify(VerifyOption vo, bool *failures) const;
816
817 // Override; it uses the "prev" marking information
818 virtual void verify() const;
819 };
820
821 // HeapRegionClosure is used for iterating over regions.
822 // Terminates the iteration when the "doHeapRegion" method returns "true".
823 class HeapRegionClosure : public StackObj {
824 friend class HeapRegionSeq;
825 friend class G1CollectedHeap;
826
827 bool _complete;
828 void incomplete() { _complete = false; }
829
830 public:
831 HeapRegionClosure(): _complete(true) {}
832
833 // Typically called on each region until it returns true.
834 virtual bool doHeapRegion(HeapRegion* r) = 0;
835
836 // True after iteration if the closure was applied to all heap regions
837 // and returned "false" in all cases.
838 bool complete() { return _complete; }
839 };
840
841 #endif // INCLUDE_ALL_GCS
842
843 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP