Wed, 18 Apr 2012 13:39:55 -0400
7145441: G1: collection set chooser-related cleanup
Summary: Cleanup of the CSet chooser class: standardize on uints for region num and indexes (instead of int, jint, etc.), make the method / field naming style more consistent, remove a lot of dead code.
Reviewed-by: johnc, brutisso
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.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"
36 #ifndef SERIALGC
38 // A HeapRegion is the smallest piece of a G1CollectedHeap that
39 // can be collected independently.
41 // NOTE: Although a HeapRegion is a Space, its
42 // Space::initDirtyCardClosure method must not be called.
43 // The problem is that the existence of this method breaks
44 // the independence of barrier sets from remembered sets.
45 // The solution is to remove this method from the definition
46 // of a Space.
48 class CompactibleSpace;
49 class ContiguousSpace;
50 class HeapRegionRemSet;
51 class HeapRegionRemSetIterator;
52 class HeapRegion;
53 class HeapRegionSetBase;
55 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
56 #define HR_FORMAT_PARAMS(_hr_) \
57 (_hr_)->hrs_index(), \
58 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : "-", \
59 (_hr_)->bottom(), (_hr_)->top(), (_hr_)->end()
61 // sentinel value for hrs_index
62 #define G1_NULL_HRS_INDEX ((uint) -1)
64 // A dirty card to oop closure for heap regions. It
65 // knows how to get the G1 heap and how to use the bitmap
66 // in the concurrent marker used by G1 to filter remembered
67 // sets.
69 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
70 public:
71 // Specification of possible DirtyCardToOopClosure filtering.
72 enum FilterKind {
73 NoFilterKind,
74 IntoCSFilterKind,
75 OutOfRegionFilterKind
76 };
78 protected:
79 HeapRegion* _hr;
80 FilterKind _fk;
81 G1CollectedHeap* _g1;
83 void walk_mem_region_with_cl(MemRegion mr,
84 HeapWord* bottom, HeapWord* top,
85 OopClosure* cl);
87 // We don't specialize this for FilteringClosure; filtering is handled by
88 // the "FilterKind" mechanism. But we provide this to avoid a compiler
89 // warning.
90 void walk_mem_region_with_cl(MemRegion mr,
91 HeapWord* bottom, HeapWord* top,
92 FilteringClosure* cl) {
93 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
94 (OopClosure*)cl);
95 }
97 // Get the actual top of the area on which the closure will
98 // operate, given where the top is assumed to be (the end of the
99 // memory region passed to do_MemRegion) and where the object
100 // at the top is assumed to start. For example, an object may
101 // start at the top but actually extend past the assumed top,
102 // in which case the top becomes the end of the object.
103 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
104 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
105 }
107 // Walk the given memory region from bottom to (actual) top
108 // looking for objects and applying the oop closure (_cl) to
109 // them. The base implementation of this treats the area as
110 // blocks, where a block may or may not be an object. Sub-
111 // classes should override this to provide more accurate
112 // or possibly more efficient walking.
113 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) {
114 Filtering_DCTOC::walk_mem_region(mr, bottom, top);
115 }
117 public:
118 HeapRegionDCTOC(G1CollectedHeap* g1,
119 HeapRegion* hr, OopClosure* cl,
120 CardTableModRefBS::PrecisionStyle precision,
121 FilterKind fk);
122 };
124 // The complicating factor is that BlockOffsetTable diverged
125 // significantly, and we need functionality that is only in the G1 version.
126 // So I copied that code, which led to an alternate G1 version of
127 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
128 // be reconciled, then G1OffsetTableContigSpace could go away.
130 // The idea behind time stamps is the following. Doing a save_marks on
131 // all regions at every GC pause is time consuming (if I remember
132 // well, 10ms or so). So, we would like to do that only for regions
133 // that are GC alloc regions. To achieve this, we use time
134 // stamps. For every evacuation pause, G1CollectedHeap generates a
135 // unique time stamp (essentially a counter that gets
136 // incremented). Every time we want to call save_marks on a region,
137 // we set the saved_mark_word to top and also copy the current GC
138 // time stamp to the time stamp field of the space. Reading the
139 // saved_mark_word involves checking the time stamp of the
140 // region. If it is the same as the current GC time stamp, then we
141 // can safely read the saved_mark_word field, as it is valid. If the
142 // time stamp of the region is not the same as the current GC time
143 // stamp, then we instead read top, as the saved_mark_word field is
144 // invalid. Time stamps (on the regions and also on the
145 // G1CollectedHeap) are reset at every cleanup (we iterate over
146 // the regions anyway) and at the end of a Full GC. The current scheme
147 // that uses sequential unsigned ints will fail only if we have 4b
148 // evacuation pauses between two cleanups, which is _highly_ unlikely.
150 class G1OffsetTableContigSpace: public ContiguousSpace {
151 friend class VMStructs;
152 protected:
153 G1BlockOffsetArrayContigSpace _offsets;
154 Mutex _par_alloc_lock;
155 volatile unsigned _gc_time_stamp;
156 // When we need to retire an allocation region, while other threads
157 // are also concurrently trying to allocate into it, we typically
158 // allocate a dummy object at the end of the region to ensure that
159 // no more allocations can take place in it. However, sometimes we
160 // want to know where the end of the last "real" object we allocated
161 // into the region was and this is what this keeps track.
162 HeapWord* _pre_dummy_top;
164 public:
165 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be
166 // assumed to contain zeros.
167 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
168 MemRegion mr, bool is_zeroed = false);
170 void set_bottom(HeapWord* value);
171 void set_end(HeapWord* value);
173 virtual HeapWord* saved_mark_word() const;
174 virtual void set_saved_mark();
175 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
177 // See the comment above in the declaration of _pre_dummy_top for an
178 // explanation of what it is.
179 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
180 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
181 _pre_dummy_top = pre_dummy_top;
182 }
183 HeapWord* pre_dummy_top() {
184 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
185 }
186 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
188 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
189 virtual void clear(bool mangle_space);
191 HeapWord* block_start(const void* p);
192 HeapWord* block_start_const(const void* p) const;
194 // Add offset table update.
195 virtual HeapWord* allocate(size_t word_size);
196 HeapWord* par_allocate(size_t word_size);
198 // MarkSweep support phase3
199 virtual HeapWord* initialize_threshold();
200 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
202 virtual void print() const;
204 void reset_bot() {
205 _offsets.zero_bottom_entry();
206 _offsets.initialize_threshold();
207 }
209 void update_bot_for_object(HeapWord* start, size_t word_size) {
210 _offsets.alloc_block(start, word_size);
211 }
213 void print_bot_on(outputStream* out) {
214 _offsets.print_on(out);
215 }
216 };
218 class HeapRegion: public G1OffsetTableContigSpace {
219 friend class VMStructs;
220 private:
222 enum HumongousType {
223 NotHumongous = 0,
224 StartsHumongous,
225 ContinuesHumongous
226 };
228 // Requires that the region "mr" be dense with objects, and begin and end
229 // with an object.
230 void oops_in_mr_iterate(MemRegion mr, OopClosure* cl);
232 // The remembered set for this region.
233 // (Might want to make this "inline" later, to avoid some alloc failure
234 // issues.)
235 HeapRegionRemSet* _rem_set;
237 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
239 protected:
240 // The index of this region in the heap region sequence.
241 uint _hrs_index;
243 HumongousType _humongous_type;
244 // For a humongous region, region in which it starts.
245 HeapRegion* _humongous_start_region;
246 // For the start region of a humongous sequence, it's original end().
247 HeapWord* _orig_end;
249 // True iff the region is in current collection_set.
250 bool _in_collection_set;
252 // True iff an attempt to evacuate an object in the region failed.
253 bool _evacuation_failed;
255 // A heap region may be a member one of a number of special subsets, each
256 // represented as linked lists through the field below. Currently, these
257 // sets include:
258 // The collection set.
259 // The set of allocation regions used in a collection pause.
260 // Spaces that may contain gray objects.
261 HeapRegion* _next_in_special_set;
263 // next region in the young "generation" region set
264 HeapRegion* _next_young_region;
266 // Next region whose cards need cleaning
267 HeapRegion* _next_dirty_cards_region;
269 // Fields used by the HeapRegionSetBase class and subclasses.
270 HeapRegion* _next;
271 #ifdef ASSERT
272 HeapRegionSetBase* _containing_set;
273 #endif // ASSERT
274 bool _pending_removal;
276 // For parallel heapRegion traversal.
277 jint _claimed;
279 // We use concurrent marking to determine the amount of live data
280 // in each heap region.
281 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
282 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
284 // The calculated GC efficiency of the region.
285 double _gc_efficiency;
287 enum YoungType {
288 NotYoung, // a region is not young
289 Young, // a region is young
290 Survivor // a region is young and it contains survivors
291 };
293 volatile YoungType _young_type;
294 int _young_index_in_cset;
295 SurvRateGroup* _surv_rate_group;
296 int _age_index;
298 // The start of the unmarked area. The unmarked area extends from this
299 // word until the top and/or end of the region, and is the part
300 // of the region for which no marking was done, i.e. objects may
301 // have been allocated in this part since the last mark phase.
302 // "prev" is the top at the start of the last completed marking.
303 // "next" is the top at the start of the in-progress marking (if any.)
304 HeapWord* _prev_top_at_mark_start;
305 HeapWord* _next_top_at_mark_start;
306 // If a collection pause is in progress, this is the top at the start
307 // of that pause.
309 // We've counted the marked bytes of objects below here.
310 HeapWord* _top_at_conc_mark_count;
312 void init_top_at_mark_start() {
313 assert(_prev_marked_bytes == 0 &&
314 _next_marked_bytes == 0,
315 "Must be called after zero_marked_bytes.");
316 HeapWord* bot = bottom();
317 _prev_top_at_mark_start = bot;
318 _next_top_at_mark_start = bot;
319 _top_at_conc_mark_count = bot;
320 }
322 void set_young_type(YoungType new_type) {
323 //assert(_young_type != new_type, "setting the same type" );
324 // TODO: add more assertions here
325 _young_type = new_type;
326 }
328 // Cached attributes used in the collection set policy information
330 // The RSet length that was added to the total value
331 // for the collection set.
332 size_t _recorded_rs_length;
334 // The predicted elapsed time that was added to total value
335 // for the collection set.
336 double _predicted_elapsed_time_ms;
338 // The predicted number of bytes to copy that was added to
339 // the total value for the collection set.
340 size_t _predicted_bytes_to_copy;
342 public:
343 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros.
344 HeapRegion(uint hrs_index,
345 G1BlockOffsetSharedArray* sharedOffsetArray,
346 MemRegion mr, bool is_zeroed);
348 static int LogOfHRGrainBytes;
349 static int LogOfHRGrainWords;
351 static size_t GrainBytes;
352 static size_t GrainWords;
353 static size_t CardsPerRegion;
355 static size_t align_up_to_region_byte_size(size_t sz) {
356 return (sz + (size_t) GrainBytes - 1) &
357 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
358 }
360 // It sets up the heap region size (GrainBytes / GrainWords), as
361 // well as other related fields that are based on the heap region
362 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
363 // CardsPerRegion). All those fields are considered constant
364 // throughout the JVM's execution, therefore they should only be set
365 // up once during initialization time.
366 static void setup_heap_region_size(uintx min_heap_size);
368 enum ClaimValues {
369 InitialClaimValue = 0,
370 FinalCountClaimValue = 1,
371 NoteEndClaimValue = 2,
372 ScrubRemSetClaimValue = 3,
373 ParVerifyClaimValue = 4,
374 RebuildRSClaimValue = 5,
375 ParEvacFailureClaimValue = 6,
376 AggregateCountClaimValue = 7,
377 VerifyCountClaimValue = 8
378 };
380 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
381 assert(is_young(), "we can only skip BOT updates on young regions");
382 return ContiguousSpace::par_allocate(word_size);
383 }
384 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
385 assert(is_young(), "we can only skip BOT updates on young regions");
386 return ContiguousSpace::allocate(word_size);
387 }
389 // If this region is a member of a HeapRegionSeq, the index in that
390 // sequence, otherwise -1.
391 uint hrs_index() const { return _hrs_index; }
393 // The number of bytes marked live in the region in the last marking phase.
394 size_t marked_bytes() { return _prev_marked_bytes; }
395 size_t live_bytes() {
396 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
397 }
399 // The number of bytes counted in the next marking.
400 size_t next_marked_bytes() { return _next_marked_bytes; }
401 // The number of bytes live wrt the next marking.
402 size_t next_live_bytes() {
403 return
404 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
405 }
407 // A lower bound on the amount of garbage bytes in the region.
408 size_t garbage_bytes() {
409 size_t used_at_mark_start_bytes =
410 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
411 assert(used_at_mark_start_bytes >= marked_bytes(),
412 "Can't mark more than we have.");
413 return used_at_mark_start_bytes - marked_bytes();
414 }
416 // Return the amount of bytes we'll reclaim if we collect this
417 // region. This includes not only the known garbage bytes in the
418 // region but also any unallocated space in it, i.e., [top, end),
419 // since it will also be reclaimed if we collect the region.
420 size_t reclaimable_bytes() {
421 size_t known_live_bytes = live_bytes();
422 assert(known_live_bytes <= capacity(), "sanity");
423 return capacity() - known_live_bytes;
424 }
426 // An upper bound on the number of live bytes in the region.
427 size_t max_live_bytes() { return used() - garbage_bytes(); }
429 void add_to_marked_bytes(size_t incr_bytes) {
430 _next_marked_bytes = _next_marked_bytes + incr_bytes;
431 assert(_next_marked_bytes <= used(), "invariant" );
432 }
434 void zero_marked_bytes() {
435 _prev_marked_bytes = _next_marked_bytes = 0;
436 }
438 bool isHumongous() const { return _humongous_type != NotHumongous; }
439 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
440 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
441 // For a humongous region, region in which it starts.
442 HeapRegion* humongous_start_region() const {
443 return _humongous_start_region;
444 }
446 // Same as Space::is_in_reserved, but will use the original size of the region.
447 // The original size is different only for start humongous regions. They get
448 // their _end set up to be the end of the last continues region of the
449 // corresponding humongous object.
450 bool is_in_reserved_raw(const void* p) const {
451 return _bottom <= p && p < _orig_end;
452 }
454 // Makes the current region be a "starts humongous" region, i.e.,
455 // the first region in a series of one or more contiguous regions
456 // that will contain a single "humongous" object. The two parameters
457 // are as follows:
458 //
459 // new_top : The new value of the top field of this region which
460 // points to the end of the humongous object that's being
461 // allocated. If there is more than one region in the series, top
462 // will lie beyond this region's original end field and on the last
463 // region in the series.
464 //
465 // new_end : The new value of the end field of this region which
466 // points to the end of the last region in the series. If there is
467 // one region in the series (namely: this one) end will be the same
468 // as the original end of this region.
469 //
470 // Updating top and end as described above makes this region look as
471 // if it spans the entire space taken up by all the regions in the
472 // series and an single allocation moved its top to new_top. This
473 // ensures that the space (capacity / allocated) taken up by all
474 // humongous regions can be calculated by just looking at the
475 // "starts humongous" regions and by ignoring the "continues
476 // humongous" regions.
477 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
479 // Makes the current region be a "continues humongous'
480 // region. first_hr is the "start humongous" region of the series
481 // which this region will be part of.
482 void set_continuesHumongous(HeapRegion* first_hr);
484 // Unsets the humongous-related fields on the region.
485 void set_notHumongous();
487 // If the region has a remembered set, return a pointer to it.
488 HeapRegionRemSet* rem_set() const {
489 return _rem_set;
490 }
492 // True iff the region is in current collection_set.
493 bool in_collection_set() const {
494 return _in_collection_set;
495 }
496 void set_in_collection_set(bool b) {
497 _in_collection_set = b;
498 }
499 HeapRegion* next_in_collection_set() {
500 assert(in_collection_set(), "should only invoke on member of CS.");
501 assert(_next_in_special_set == NULL ||
502 _next_in_special_set->in_collection_set(),
503 "Malformed CS.");
504 return _next_in_special_set;
505 }
506 void set_next_in_collection_set(HeapRegion* r) {
507 assert(in_collection_set(), "should only invoke on member of CS.");
508 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
509 _next_in_special_set = r;
510 }
512 // Methods used by the HeapRegionSetBase class and subclasses.
514 // Getter and setter for the next field used to link regions into
515 // linked lists.
516 HeapRegion* next() { return _next; }
518 void set_next(HeapRegion* next) { _next = next; }
520 // Every region added to a set is tagged with a reference to that
521 // set. This is used for doing consistency checking to make sure that
522 // the contents of a set are as they should be and it's only
523 // available in non-product builds.
524 #ifdef ASSERT
525 void set_containing_set(HeapRegionSetBase* containing_set) {
526 assert((containing_set == NULL && _containing_set != NULL) ||
527 (containing_set != NULL && _containing_set == NULL),
528 err_msg("containing_set: "PTR_FORMAT" "
529 "_containing_set: "PTR_FORMAT,
530 containing_set, _containing_set));
532 _containing_set = containing_set;
533 }
535 HeapRegionSetBase* containing_set() { return _containing_set; }
536 #else // ASSERT
537 void set_containing_set(HeapRegionSetBase* containing_set) { }
539 // containing_set() is only used in asserts so there's no reason
540 // to provide a dummy version of it.
541 #endif // ASSERT
543 // If we want to remove regions from a list in bulk we can simply tag
544 // them with the pending_removal tag and call the
545 // remove_all_pending() method on the list.
547 bool pending_removal() { return _pending_removal; }
549 void set_pending_removal(bool pending_removal) {
550 if (pending_removal) {
551 assert(!_pending_removal && containing_set() != NULL,
552 "can only set pending removal to true if it's false and "
553 "the region belongs to a region set");
554 } else {
555 assert( _pending_removal && containing_set() == NULL,
556 "can only set pending removal to false if it's true and "
557 "the region does not belong to a region set");
558 }
560 _pending_removal = pending_removal;
561 }
563 HeapRegion* get_next_young_region() { return _next_young_region; }
564 void set_next_young_region(HeapRegion* hr) {
565 _next_young_region = hr;
566 }
568 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
569 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
570 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
571 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
573 HeapWord* orig_end() { return _orig_end; }
575 // Allows logical separation between objects allocated before and after.
576 void save_marks();
578 // Reset HR stuff to default values.
579 void hr_clear(bool par, bool clear_space);
580 void par_clear();
582 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
584 // Get the start of the unmarked area in this region.
585 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
586 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
588 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
589 // allocated in the current region before the last call to "save_mark".
590 void oop_before_save_marks_iterate(OopClosure* cl);
592 // Note the start or end of marking. This tells the heap region
593 // that the collector is about to start or has finished (concurrently)
594 // marking the heap.
596 // Notify the region that concurrent marking is starting. Initialize
597 // all fields related to the next marking info.
598 inline void note_start_of_marking();
600 // Notify the region that concurrent marking has finished. Copy the
601 // (now finalized) next marking info fields into the prev marking
602 // info fields.
603 inline void note_end_of_marking();
605 // Notify the region that it will be used as to-space during a GC
606 // and we are about to start copying objects into it.
607 inline void note_start_of_copying(bool during_initial_mark);
609 // Notify the region that it ceases being to-space during a GC and
610 // we will not copy objects into it any more.
611 inline void note_end_of_copying(bool during_initial_mark);
613 // Notify the region that we are about to start processing
614 // self-forwarded objects during evac failure handling.
615 void note_self_forwarding_removal_start(bool during_initial_mark,
616 bool during_conc_mark);
618 // Notify the region that we have finished processing self-forwarded
619 // objects during evac failure handling.
620 void note_self_forwarding_removal_end(bool during_initial_mark,
621 bool during_conc_mark,
622 size_t marked_bytes);
624 // Returns "false" iff no object in the region was allocated when the
625 // last mark phase ended.
626 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
628 void init_top_at_conc_mark_count() {
629 _top_at_conc_mark_count = bottom();
630 }
632 void set_top_at_conc_mark_count(HeapWord *cur) {
633 assert(bottom() <= cur && cur <= end(), "Sanity.");
634 _top_at_conc_mark_count = cur;
635 }
637 HeapWord* top_at_conc_mark_count() {
638 return _top_at_conc_mark_count;
639 }
641 void reset_during_compaction() {
642 guarantee( isHumongous() && startsHumongous(),
643 "should only be called for humongous regions");
645 zero_marked_bytes();
646 init_top_at_mark_start();
647 }
649 void calc_gc_efficiency(void);
650 double gc_efficiency() { return _gc_efficiency;}
652 bool is_young() const { return _young_type != NotYoung; }
653 bool is_survivor() const { return _young_type == Survivor; }
655 int young_index_in_cset() const { return _young_index_in_cset; }
656 void set_young_index_in_cset(int index) {
657 assert( (index == -1) || is_young(), "pre-condition" );
658 _young_index_in_cset = index;
659 }
661 int age_in_surv_rate_group() {
662 assert( _surv_rate_group != NULL, "pre-condition" );
663 assert( _age_index > -1, "pre-condition" );
664 return _surv_rate_group->age_in_group(_age_index);
665 }
667 void record_surv_words_in_group(size_t words_survived) {
668 assert( _surv_rate_group != NULL, "pre-condition" );
669 assert( _age_index > -1, "pre-condition" );
670 int age_in_group = age_in_surv_rate_group();
671 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
672 }
674 int age_in_surv_rate_group_cond() {
675 if (_surv_rate_group != NULL)
676 return age_in_surv_rate_group();
677 else
678 return -1;
679 }
681 SurvRateGroup* surv_rate_group() {
682 return _surv_rate_group;
683 }
685 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
686 assert( surv_rate_group != NULL, "pre-condition" );
687 assert( _surv_rate_group == NULL, "pre-condition" );
688 assert( is_young(), "pre-condition" );
690 _surv_rate_group = surv_rate_group;
691 _age_index = surv_rate_group->next_age_index();
692 }
694 void uninstall_surv_rate_group() {
695 if (_surv_rate_group != NULL) {
696 assert( _age_index > -1, "pre-condition" );
697 assert( is_young(), "pre-condition" );
699 _surv_rate_group = NULL;
700 _age_index = -1;
701 } else {
702 assert( _age_index == -1, "pre-condition" );
703 }
704 }
706 void set_young() { set_young_type(Young); }
708 void set_survivor() { set_young_type(Survivor); }
710 void set_not_young() { set_young_type(NotYoung); }
712 // Determine if an object has been allocated since the last
713 // mark performed by the collector. This returns true iff the object
714 // is within the unmarked area of the region.
715 bool obj_allocated_since_prev_marking(oop obj) const {
716 return (HeapWord *) obj >= prev_top_at_mark_start();
717 }
718 bool obj_allocated_since_next_marking(oop obj) const {
719 return (HeapWord *) obj >= next_top_at_mark_start();
720 }
722 // For parallel heapRegion traversal.
723 bool claimHeapRegion(int claimValue);
724 jint claim_value() { return _claimed; }
725 // Use this carefully: only when you're sure no one is claiming...
726 void set_claim_value(int claimValue) { _claimed = claimValue; }
728 // Returns the "evacuation_failed" property of the region.
729 bool evacuation_failed() { return _evacuation_failed; }
731 // Sets the "evacuation_failed" property of the region.
732 void set_evacuation_failed(bool b) {
733 _evacuation_failed = b;
735 if (b) {
736 init_top_at_conc_mark_count();
737 _next_marked_bytes = 0;
738 }
739 }
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);
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);
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 }
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);
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; }
779 void set_recorded_rs_length(size_t rs_length) {
780 _recorded_rs_length = rs_length;
781 }
783 void set_predicted_elapsed_time_ms(double ms) {
784 _predicted_elapsed_time_ms = ms;
785 }
787 void set_predicted_bytes_to_copy(size_t bytes) {
788 _predicted_bytes_to_copy = bytes;
789 }
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)
795 CompactibleSpace* next_compaction_space() const;
797 virtual void reset_after_compaction();
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 // SERIALGC
843 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP