Wed, 25 Jun 2014 16:53:13 +0200
8047820: G1 Block offset table does not need to support generic Space classes
Reviewed-by: tschatzl, stefank
1 /*
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
28 #include "gc_implementation/g1/g1BlockOffsetTable.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"
37 #if INCLUDE_ALL_GCS
39 // A HeapRegion is the smallest piece of a G1CollectedHeap that
40 // can be collected independently.
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.
49 class CompactibleSpace;
50 class ContiguousSpace;
51 class HeapRegionRemSet;
52 class HeapRegionRemSetIterator;
53 class HeapRegion;
54 class HeapRegionSetBase;
55 class nmethod;
57 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
58 #define HR_FORMAT_PARAMS(_hr_) \
59 (_hr_)->hrs_index(), \
60 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \
61 (_hr_)->startsHumongous() ? "HS" : \
62 (_hr_)->continuesHumongous() ? "HC" : \
63 !(_hr_)->is_empty() ? "O" : "F", \
64 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
66 // sentinel value for hrs_index
67 #define G1_NULL_HRS_INDEX ((uint) -1)
69 // A dirty card to oop closure for heap regions. It
70 // knows how to get the G1 heap and how to use the bitmap
71 // in the concurrent marker used by G1 to filter remembered
72 // sets.
74 class HeapRegionDCTOC : public DirtyCardToOopClosure {
75 public:
76 // Specification of possible DirtyCardToOopClosure filtering.
77 enum FilterKind {
78 NoFilterKind,
79 IntoCSFilterKind,
80 OutOfRegionFilterKind
81 };
83 protected:
84 HeapRegion* _hr;
85 FilterKind _fk;
86 G1CollectedHeap* _g1;
88 // Walk the given memory region from bottom to (actual) top
89 // looking for objects and applying the oop closure (_cl) to
90 // them. The base implementation of this treats the area as
91 // blocks, where a block may or may not be an object. Sub-
92 // classes should override this to provide more accurate
93 // or possibly more efficient walking.
94 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
96 public:
97 HeapRegionDCTOC(G1CollectedHeap* g1,
98 HeapRegion* hr, ExtendedOopClosure* cl,
99 CardTableModRefBS::PrecisionStyle precision,
100 FilterKind fk);
101 };
103 // The complicating factor is that BlockOffsetTable diverged
104 // significantly, and we need functionality that is only in the G1 version.
105 // So I copied that code, which led to an alternate G1 version of
106 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
107 // be reconciled, then G1OffsetTableContigSpace could go away.
109 // The idea behind time stamps is the following. Doing a save_marks on
110 // all regions at every GC pause is time consuming (if I remember
111 // well, 10ms or so). So, we would like to do that only for regions
112 // that are GC alloc regions. To achieve this, we use time
113 // stamps. For every evacuation pause, G1CollectedHeap generates a
114 // unique time stamp (essentially a counter that gets
115 // incremented). Every time we want to call save_marks on a region,
116 // we set the saved_mark_word to top and also copy the current GC
117 // time stamp to the time stamp field of the space. Reading the
118 // saved_mark_word involves checking the time stamp of the
119 // region. If it is the same as the current GC time stamp, then we
120 // can safely read the saved_mark_word field, as it is valid. If the
121 // time stamp of the region is not the same as the current GC time
122 // stamp, then we instead read top, as the saved_mark_word field is
123 // invalid. Time stamps (on the regions and also on the
124 // G1CollectedHeap) are reset at every cleanup (we iterate over
125 // the regions anyway) and at the end of a Full GC. The current scheme
126 // that uses sequential unsigned ints will fail only if we have 4b
127 // evacuation pauses between two cleanups, which is _highly_ unlikely.
129 class G1OffsetTableContigSpace: public ContiguousSpace {
130 friend class VMStructs;
131 protected:
132 G1BlockOffsetArrayContigSpace _offsets;
133 Mutex _par_alloc_lock;
134 volatile unsigned _gc_time_stamp;
135 // When we need to retire an allocation region, while other threads
136 // are also concurrently trying to allocate into it, we typically
137 // allocate a dummy object at the end of the region to ensure that
138 // no more allocations can take place in it. However, sometimes we
139 // want to know where the end of the last "real" object we allocated
140 // into the region was and this is what this keeps track.
141 HeapWord* _pre_dummy_top;
143 public:
144 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
145 MemRegion mr);
147 void set_bottom(HeapWord* value);
148 void set_end(HeapWord* value);
150 virtual HeapWord* saved_mark_word() const;
151 virtual void set_saved_mark();
152 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
153 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
155 // See the comment above in the declaration of _pre_dummy_top for an
156 // explanation of what it is.
157 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
158 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
159 _pre_dummy_top = pre_dummy_top;
160 }
161 HeapWord* pre_dummy_top() {
162 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
163 }
164 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
166 virtual void clear(bool mangle_space);
168 HeapWord* block_start(const void* p);
169 HeapWord* block_start_const(const void* p) const;
171 // Add offset table update.
172 virtual HeapWord* allocate(size_t word_size);
173 HeapWord* par_allocate(size_t word_size);
175 // MarkSweep support phase3
176 virtual HeapWord* initialize_threshold();
177 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
179 virtual void print() const;
181 void reset_bot() {
182 _offsets.zero_bottom_entry();
183 _offsets.initialize_threshold();
184 }
186 void update_bot_for_object(HeapWord* start, size_t word_size) {
187 _offsets.alloc_block(start, word_size);
188 }
190 void print_bot_on(outputStream* out) {
191 _offsets.print_on(out);
192 }
193 };
195 class HeapRegion: public G1OffsetTableContigSpace {
196 friend class VMStructs;
197 private:
199 enum HumongousType {
200 NotHumongous = 0,
201 StartsHumongous,
202 ContinuesHumongous
203 };
205 // Requires that the region "mr" be dense with objects, and begin and end
206 // with an object.
207 void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl);
209 // The remembered set for this region.
210 // (Might want to make this "inline" later, to avoid some alloc failure
211 // issues.)
212 HeapRegionRemSet* _rem_set;
214 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
216 protected:
217 // The index of this region in the heap region sequence.
218 uint _hrs_index;
220 HumongousType _humongous_type;
221 // For a humongous region, region in which it starts.
222 HeapRegion* _humongous_start_region;
223 // For the start region of a humongous sequence, it's original end().
224 HeapWord* _orig_end;
226 // True iff the region is in current collection_set.
227 bool _in_collection_set;
229 // True iff an attempt to evacuate an object in the region failed.
230 bool _evacuation_failed;
232 // A heap region may be a member one of a number of special subsets, each
233 // represented as linked lists through the field below. Currently, these
234 // sets include:
235 // The collection set.
236 // The set of allocation regions used in a collection pause.
237 // Spaces that may contain gray objects.
238 HeapRegion* _next_in_special_set;
240 // next region in the young "generation" region set
241 HeapRegion* _next_young_region;
243 // Next region whose cards need cleaning
244 HeapRegion* _next_dirty_cards_region;
246 // Fields used by the HeapRegionSetBase class and subclasses.
247 HeapRegion* _next;
248 HeapRegion* _prev;
249 #ifdef ASSERT
250 HeapRegionSetBase* _containing_set;
251 #endif // ASSERT
252 bool _pending_removal;
254 // For parallel heapRegion traversal.
255 jint _claimed;
257 // We use concurrent marking to determine the amount of live data
258 // in each heap region.
259 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
260 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
262 // The calculated GC efficiency of the region.
263 double _gc_efficiency;
265 enum YoungType {
266 NotYoung, // a region is not young
267 Young, // a region is young
268 Survivor // a region is young and it contains survivors
269 };
271 volatile YoungType _young_type;
272 int _young_index_in_cset;
273 SurvRateGroup* _surv_rate_group;
274 int _age_index;
276 // The start of the unmarked area. The unmarked area extends from this
277 // word until the top and/or end of the region, and is the part
278 // of the region for which no marking was done, i.e. objects may
279 // have been allocated in this part since the last mark phase.
280 // "prev" is the top at the start of the last completed marking.
281 // "next" is the top at the start of the in-progress marking (if any.)
282 HeapWord* _prev_top_at_mark_start;
283 HeapWord* _next_top_at_mark_start;
284 // If a collection pause is in progress, this is the top at the start
285 // of that pause.
287 void init_top_at_mark_start() {
288 assert(_prev_marked_bytes == 0 &&
289 _next_marked_bytes == 0,
290 "Must be called after zero_marked_bytes.");
291 HeapWord* bot = bottom();
292 _prev_top_at_mark_start = bot;
293 _next_top_at_mark_start = bot;
294 }
296 void set_young_type(YoungType new_type) {
297 //assert(_young_type != new_type, "setting the same type" );
298 // TODO: add more assertions here
299 _young_type = new_type;
300 }
302 // Cached attributes used in the collection set policy information
304 // The RSet length that was added to the total value
305 // for the collection set.
306 size_t _recorded_rs_length;
308 // The predicted elapsed time that was added to total value
309 // for the collection set.
310 double _predicted_elapsed_time_ms;
312 // The predicted number of bytes to copy that was added to
313 // the total value for the collection set.
314 size_t _predicted_bytes_to_copy;
316 public:
317 HeapRegion(uint hrs_index,
318 G1BlockOffsetSharedArray* sharedOffsetArray,
319 MemRegion mr);
321 static int LogOfHRGrainBytes;
322 static int LogOfHRGrainWords;
324 static size_t GrainBytes;
325 static size_t GrainWords;
326 static size_t CardsPerRegion;
328 static size_t align_up_to_region_byte_size(size_t sz) {
329 return (sz + (size_t) GrainBytes - 1) &
330 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
331 }
333 static size_t max_region_size();
335 // It sets up the heap region size (GrainBytes / GrainWords), as
336 // well as other related fields that are based on the heap region
337 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
338 // CardsPerRegion). All those fields are considered constant
339 // throughout the JVM's execution, therefore they should only be set
340 // up once during initialization time.
341 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
343 enum ClaimValues {
344 InitialClaimValue = 0,
345 FinalCountClaimValue = 1,
346 NoteEndClaimValue = 2,
347 ScrubRemSetClaimValue = 3,
348 ParVerifyClaimValue = 4,
349 RebuildRSClaimValue = 5,
350 ParEvacFailureClaimValue = 6,
351 AggregateCountClaimValue = 7,
352 VerifyCountClaimValue = 8,
353 ParMarkRootClaimValue = 9
354 };
356 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
357 assert(is_young(), "we can only skip BOT updates on young regions");
358 return ContiguousSpace::par_allocate(word_size);
359 }
360 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
361 assert(is_young(), "we can only skip BOT updates on young regions");
362 return ContiguousSpace::allocate(word_size);
363 }
365 // If this region is a member of a HeapRegionSeq, the index in that
366 // sequence, otherwise -1.
367 uint hrs_index() const { return _hrs_index; }
369 // The number of bytes marked live in the region in the last marking phase.
370 size_t marked_bytes() { return _prev_marked_bytes; }
371 size_t live_bytes() {
372 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
373 }
375 // The number of bytes counted in the next marking.
376 size_t next_marked_bytes() { return _next_marked_bytes; }
377 // The number of bytes live wrt the next marking.
378 size_t next_live_bytes() {
379 return
380 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
381 }
383 // A lower bound on the amount of garbage bytes in the region.
384 size_t garbage_bytes() {
385 size_t used_at_mark_start_bytes =
386 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
387 assert(used_at_mark_start_bytes >= marked_bytes(),
388 "Can't mark more than we have.");
389 return used_at_mark_start_bytes - marked_bytes();
390 }
392 // Return the amount of bytes we'll reclaim if we collect this
393 // region. This includes not only the known garbage bytes in the
394 // region but also any unallocated space in it, i.e., [top, end),
395 // since it will also be reclaimed if we collect the region.
396 size_t reclaimable_bytes() {
397 size_t known_live_bytes = live_bytes();
398 assert(known_live_bytes <= capacity(), "sanity");
399 return capacity() - known_live_bytes;
400 }
402 // An upper bound on the number of live bytes in the region.
403 size_t max_live_bytes() { return used() - garbage_bytes(); }
405 void add_to_marked_bytes(size_t incr_bytes) {
406 _next_marked_bytes = _next_marked_bytes + incr_bytes;
407 assert(_next_marked_bytes <= used(), "invariant" );
408 }
410 void zero_marked_bytes() {
411 _prev_marked_bytes = _next_marked_bytes = 0;
412 }
414 bool isHumongous() const { return _humongous_type != NotHumongous; }
415 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
416 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
417 // For a humongous region, region in which it starts.
418 HeapRegion* humongous_start_region() const {
419 return _humongous_start_region;
420 }
422 // Return the number of distinct regions that are covered by this region:
423 // 1 if the region is not humongous, >= 1 if the region is humongous.
424 uint region_num() const {
425 if (!isHumongous()) {
426 return 1U;
427 } else {
428 assert(startsHumongous(), "doesn't make sense on HC regions");
429 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
430 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
431 }
432 }
434 // Return the index + 1 of the last HC regions that's associated
435 // with this HS region.
436 uint last_hc_index() const {
437 assert(startsHumongous(), "don't call this otherwise");
438 return hrs_index() + region_num();
439 }
441 // Same as Space::is_in_reserved, but will use the original size of the region.
442 // The original size is different only for start humongous regions. They get
443 // their _end set up to be the end of the last continues region of the
444 // corresponding humongous object.
445 bool is_in_reserved_raw(const void* p) const {
446 return _bottom <= p && p < _orig_end;
447 }
449 // Makes the current region be a "starts humongous" region, i.e.,
450 // the first region in a series of one or more contiguous regions
451 // that will contain a single "humongous" object. The two parameters
452 // are as follows:
453 //
454 // new_top : The new value of the top field of this region which
455 // points to the end of the humongous object that's being
456 // allocated. If there is more than one region in the series, top
457 // will lie beyond this region's original end field and on the last
458 // region in the series.
459 //
460 // new_end : The new value of the end field of this region which
461 // points to the end of the last region in the series. If there is
462 // one region in the series (namely: this one) end will be the same
463 // as the original end of this region.
464 //
465 // Updating top and end as described above makes this region look as
466 // if it spans the entire space taken up by all the regions in the
467 // series and an single allocation moved its top to new_top. This
468 // ensures that the space (capacity / allocated) taken up by all
469 // humongous regions can be calculated by just looking at the
470 // "starts humongous" regions and by ignoring the "continues
471 // humongous" regions.
472 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
474 // Makes the current region be a "continues humongous'
475 // region. first_hr is the "start humongous" region of the series
476 // which this region will be part of.
477 void set_continuesHumongous(HeapRegion* first_hr);
479 // Unsets the humongous-related fields on the region.
480 void set_notHumongous();
482 // If the region has a remembered set, return a pointer to it.
483 HeapRegionRemSet* rem_set() const {
484 return _rem_set;
485 }
487 // True iff the region is in current collection_set.
488 bool in_collection_set() const {
489 return _in_collection_set;
490 }
491 void set_in_collection_set(bool b) {
492 _in_collection_set = b;
493 }
494 HeapRegion* next_in_collection_set() {
495 assert(in_collection_set(), "should only invoke on member of CS.");
496 assert(_next_in_special_set == NULL ||
497 _next_in_special_set->in_collection_set(),
498 "Malformed CS.");
499 return _next_in_special_set;
500 }
501 void set_next_in_collection_set(HeapRegion* r) {
502 assert(in_collection_set(), "should only invoke on member of CS.");
503 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
504 _next_in_special_set = r;
505 }
507 // Methods used by the HeapRegionSetBase class and subclasses.
509 // Getter and setter for the next and prev fields used to link regions into
510 // linked lists.
511 HeapRegion* next() { return _next; }
512 HeapRegion* prev() { return _prev; }
514 void set_next(HeapRegion* next) { _next = next; }
515 void set_prev(HeapRegion* prev) { _prev = prev; }
517 // Every region added to a set is tagged with a reference to that
518 // set. This is used for doing consistency checking to make sure that
519 // the contents of a set are as they should be and it's only
520 // available in non-product builds.
521 #ifdef ASSERT
522 void set_containing_set(HeapRegionSetBase* containing_set) {
523 assert((containing_set == NULL && _containing_set != NULL) ||
524 (containing_set != NULL && _containing_set == NULL),
525 err_msg("containing_set: "PTR_FORMAT" "
526 "_containing_set: "PTR_FORMAT,
527 p2i(containing_set), p2i(_containing_set)));
529 _containing_set = containing_set;
530 }
532 HeapRegionSetBase* containing_set() { return _containing_set; }
533 #else // ASSERT
534 void set_containing_set(HeapRegionSetBase* containing_set) { }
536 // containing_set() is only used in asserts so there's no reason
537 // to provide a dummy version of it.
538 #endif // ASSERT
540 // If we want to remove regions from a list in bulk we can simply tag
541 // them with the pending_removal tag and call the
542 // remove_all_pending() method on the list.
544 bool pending_removal() { return _pending_removal; }
546 void set_pending_removal(bool pending_removal) {
547 if (pending_removal) {
548 assert(!_pending_removal && containing_set() != NULL,
549 "can only set pending removal to true if it's false and "
550 "the region belongs to a region set");
551 } else {
552 assert( _pending_removal && containing_set() == NULL,
553 "can only set pending removal to false if it's true and "
554 "the region does not belong to a region set");
555 }
557 _pending_removal = pending_removal;
558 }
560 HeapRegion* get_next_young_region() { return _next_young_region; }
561 void set_next_young_region(HeapRegion* hr) {
562 _next_young_region = hr;
563 }
565 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
566 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
567 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
568 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
570 HeapWord* orig_end() { return _orig_end; }
572 // Allows logical separation between objects allocated before and after.
573 void save_marks();
575 // Reset HR stuff to default values.
576 void hr_clear(bool par, bool clear_space, bool locked = false);
577 void par_clear();
579 // Get the start of the unmarked area in this region.
580 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
581 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
583 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
584 // allocated in the current region before the last call to "save_mark".
585 void oop_before_save_marks_iterate(ExtendedOopClosure* cl);
587 // Note the start or end of marking. This tells the heap region
588 // that the collector is about to start or has finished (concurrently)
589 // marking the heap.
591 // Notify the region that concurrent marking is starting. Initialize
592 // all fields related to the next marking info.
593 inline void note_start_of_marking();
595 // Notify the region that concurrent marking has finished. Copy the
596 // (now finalized) next marking info fields into the prev marking
597 // info fields.
598 inline void note_end_of_marking();
600 // Notify the region that it will be used as to-space during a GC
601 // and we are about to start copying objects into it.
602 inline void note_start_of_copying(bool during_initial_mark);
604 // Notify the region that it ceases being to-space during a GC and
605 // we will not copy objects into it any more.
606 inline void note_end_of_copying(bool during_initial_mark);
608 // Notify the region that we are about to start processing
609 // self-forwarded objects during evac failure handling.
610 void note_self_forwarding_removal_start(bool during_initial_mark,
611 bool during_conc_mark);
613 // Notify the region that we have finished processing self-forwarded
614 // objects during evac failure handling.
615 void note_self_forwarding_removal_end(bool during_initial_mark,
616 bool during_conc_mark,
617 size_t marked_bytes);
619 // Returns "false" iff no object in the region was allocated when the
620 // last mark phase ended.
621 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
623 void reset_during_compaction() {
624 assert(isHumongous() && startsHumongous(),
625 "should only be called for starts humongous regions");
627 zero_marked_bytes();
628 init_top_at_mark_start();
629 }
631 void calc_gc_efficiency(void);
632 double gc_efficiency() { return _gc_efficiency;}
634 bool is_young() const { return _young_type != NotYoung; }
635 bool is_survivor() const { return _young_type == Survivor; }
637 int young_index_in_cset() const { return _young_index_in_cset; }
638 void set_young_index_in_cset(int index) {
639 assert( (index == -1) || is_young(), "pre-condition" );
640 _young_index_in_cset = index;
641 }
643 int age_in_surv_rate_group() {
644 assert( _surv_rate_group != NULL, "pre-condition" );
645 assert( _age_index > -1, "pre-condition" );
646 return _surv_rate_group->age_in_group(_age_index);
647 }
649 void record_surv_words_in_group(size_t words_survived) {
650 assert( _surv_rate_group != NULL, "pre-condition" );
651 assert( _age_index > -1, "pre-condition" );
652 int age_in_group = age_in_surv_rate_group();
653 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
654 }
656 int age_in_surv_rate_group_cond() {
657 if (_surv_rate_group != NULL)
658 return age_in_surv_rate_group();
659 else
660 return -1;
661 }
663 SurvRateGroup* surv_rate_group() {
664 return _surv_rate_group;
665 }
667 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
668 assert( surv_rate_group != NULL, "pre-condition" );
669 assert( _surv_rate_group == NULL, "pre-condition" );
670 assert( is_young(), "pre-condition" );
672 _surv_rate_group = surv_rate_group;
673 _age_index = surv_rate_group->next_age_index();
674 }
676 void uninstall_surv_rate_group() {
677 if (_surv_rate_group != NULL) {
678 assert( _age_index > -1, "pre-condition" );
679 assert( is_young(), "pre-condition" );
681 _surv_rate_group = NULL;
682 _age_index = -1;
683 } else {
684 assert( _age_index == -1, "pre-condition" );
685 }
686 }
688 void set_young() { set_young_type(Young); }
690 void set_survivor() { set_young_type(Survivor); }
692 void set_not_young() { set_young_type(NotYoung); }
694 // Determine if an object has been allocated since the last
695 // mark performed by the collector. This returns true iff the object
696 // is within the unmarked area of the region.
697 bool obj_allocated_since_prev_marking(oop obj) const {
698 return (HeapWord *) obj >= prev_top_at_mark_start();
699 }
700 bool obj_allocated_since_next_marking(oop obj) const {
701 return (HeapWord *) obj >= next_top_at_mark_start();
702 }
704 // For parallel heapRegion traversal.
705 bool claimHeapRegion(int claimValue);
706 jint claim_value() { return _claimed; }
707 // Use this carefully: only when you're sure no one is claiming...
708 void set_claim_value(int claimValue) { _claimed = claimValue; }
710 // Returns the "evacuation_failed" property of the region.
711 bool evacuation_failed() { return _evacuation_failed; }
713 // Sets the "evacuation_failed" property of the region.
714 void set_evacuation_failed(bool b) {
715 _evacuation_failed = b;
717 if (b) {
718 _next_marked_bytes = 0;
719 }
720 }
722 // Requires that "mr" be entirely within the region.
723 // Apply "cl->do_object" to all objects that intersect with "mr".
724 // If the iteration encounters an unparseable portion of the region,
725 // or if "cl->abort()" is true after a closure application,
726 // terminate the iteration and return the address of the start of the
727 // subregion that isn't done. (The two can be distinguished by querying
728 // "cl->abort()".) Return of "NULL" indicates that the iteration
729 // completed.
730 HeapWord*
731 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
733 // filter_young: if true and the region is a young region then we
734 // skip the iteration.
735 // card_ptr: if not NULL, and we decide that the card is not young
736 // and we iterate over it, we'll clean the card before we start the
737 // iteration.
738 HeapWord*
739 oops_on_card_seq_iterate_careful(MemRegion mr,
740 FilterOutOfRegionClosure* cl,
741 bool filter_young,
742 jbyte* card_ptr);
744 // A version of block start that is guaranteed to find *some* block
745 // boundary at or before "p", but does not object iteration, and may
746 // therefore be used safely when the heap is unparseable.
747 HeapWord* block_start_careful(const void* p) const {
748 return _offsets.block_start_careful(p);
749 }
751 // Requires that "addr" is within the region. Returns the start of the
752 // first ("careful") block that starts at or after "addr", or else the
753 // "end" of the region if there is no such block.
754 HeapWord* next_block_start_careful(HeapWord* addr);
756 size_t recorded_rs_length() const { return _recorded_rs_length; }
757 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
758 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
760 void set_recorded_rs_length(size_t rs_length) {
761 _recorded_rs_length = rs_length;
762 }
764 void set_predicted_elapsed_time_ms(double ms) {
765 _predicted_elapsed_time_ms = ms;
766 }
768 void set_predicted_bytes_to_copy(size_t bytes) {
769 _predicted_bytes_to_copy = bytes;
770 }
772 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
773 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
774 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
776 virtual CompactibleSpace* next_compaction_space() const;
778 virtual void reset_after_compaction();
780 // Routines for managing a list of code roots (attached to the
781 // this region's RSet) that point into this heap region.
782 void add_strong_code_root(nmethod* nm);
783 void remove_strong_code_root(nmethod* nm);
785 // During a collection, migrate the successfully evacuated
786 // strong code roots that referenced into this region to the
787 // new regions that they now point into. Unsuccessfully
788 // evacuated code roots are not migrated.
789 void migrate_strong_code_roots();
791 // Applies blk->do_code_blob() to each of the entries in
792 // the strong code roots list for this region
793 void strong_code_roots_do(CodeBlobClosure* blk) const;
795 // Verify that the entries on the strong code root list for this
796 // region are live and include at least one pointer into this region.
797 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
799 void print() const;
800 void print_on(outputStream* st) const;
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;
817 // Override; it uses the "prev" marking information
818 virtual void verify() const;
819 };
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;
827 bool _complete;
828 void incomplete() { _complete = false; }
830 public:
831 HeapRegionClosure(): _complete(true) {}
833 // Typically called on each region until it returns true.
834 virtual bool doHeapRegion(HeapRegion* r) = 0;
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 };
841 #endif // INCLUDE_ALL_GCS
843 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP