1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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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
36 #ifndef SERIALGC
37
38 // A HeapRegion is the smallest piece of a G1CollectedHeap that
39 // can be collected independently.
40
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.
47
48 class CompactibleSpace;
49 class ContiguousSpace;
50 class HeapRegionRemSet;
51 class HeapRegionRemSetIterator;
52 class HeapRegion;
53 class HeapRegionSetBase;
54
55 #define HR_FORMAT SIZE_FORMAT":(%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()
60
61 // A dirty card to oop closure for heap regions. It
62 // knows how to get the G1 heap and how to use the bitmap
63 // in the concurrent marker used by G1 to filter remembered
64 // sets.
65
66 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
67 public:
68 // Specification of possible DirtyCardToOopClosure filtering.
69 enum FilterKind {
70 NoFilterKind,
71 IntoCSFilterKind,
72 OutOfRegionFilterKind
73 };
74
75 protected:
76 HeapRegion* _hr;
77 FilterKind _fk;
78 G1CollectedHeap* _g1;
79
80 void walk_mem_region_with_cl(MemRegion mr,
81 HeapWord* bottom, HeapWord* top,
82 OopClosure* cl);
83
84 // We don't specialize this for FilteringClosure; filtering is handled by
85 // the "FilterKind" mechanism. But we provide this to avoid a compiler
86 // warning.
87 void walk_mem_region_with_cl(MemRegion mr,
88 HeapWord* bottom, HeapWord* top,
89 FilteringClosure* cl) {
90 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
91 (OopClosure*)cl);
92 }
93
94 // Get the actual top of the area on which the closure will
95 // operate, given where the top is assumed to be (the end of the
96 // memory region passed to do_MemRegion) and where the object
97 // at the top is assumed to start. For example, an object may
98 // start at the top but actually extend past the assumed top,
99 // in which case the top becomes the end of the object.
100 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
101 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
102 }
103
104 // Walk the given memory region from bottom to (actual) top
105 // looking for objects and applying the oop closure (_cl) to
106 // them. The base implementation of this treats the area as
107 // blocks, where a block may or may not be an object. Sub-
108 // classes should override this to provide more accurate
109 // or possibly more efficient walking.
110 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) {
111 Filtering_DCTOC::walk_mem_region(mr, bottom, top);
112 }
113
114 public:
115 HeapRegionDCTOC(G1CollectedHeap* g1,
116 HeapRegion* hr, OopClosure* cl,
117 CardTableModRefBS::PrecisionStyle precision,
118 FilterKind fk);
119 };
120
121
122 // The complicating factor is that BlockOffsetTable diverged
123 // significantly, and we need functionality that is only in the G1 version.
124 // So I copied that code, which led to an alternate G1 version of
125 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
126 // be reconciled, then G1OffsetTableContigSpace could go away.
127
128 // The idea behind time stamps is the following. Doing a save_marks on
129 // all regions at every GC pause is time consuming (if I remember
130 // well, 10ms or so). So, we would like to do that only for regions
131 // that are GC alloc regions. To achieve this, we use time
132 // stamps. For every evacuation pause, G1CollectedHeap generates a
133 // unique time stamp (essentially a counter that gets
134 // incremented). Every time we want to call save_marks on a region,
135 // we set the saved_mark_word to top and also copy the current GC
136 // time stamp to the time stamp field of the space. Reading the
137 // saved_mark_word involves checking the time stamp of the
138 // region. If it is the same as the current GC time stamp, then we
139 // can safely read the saved_mark_word field, as it is valid. If the
140 // time stamp of the region is not the same as the current GC time
141 // stamp, then we instead read top, as the saved_mark_word field is
142 // invalid. Time stamps (on the regions and also on the
143 // G1CollectedHeap) are reset at every cleanup (we iterate over
144 // the regions anyway) and at the end of a Full GC. The current scheme
145 // that uses sequential unsigned ints will fail only if we have 4b
146 // evacuation pauses between two cleanups, which is _highly_ unlikely.
147
148 class G1OffsetTableContigSpace: public ContiguousSpace {
149 friend class VMStructs;
150 protected:
151 G1BlockOffsetArrayContigSpace _offsets;
152 Mutex _par_alloc_lock;
153 volatile unsigned _gc_time_stamp;
154 // When we need to retire an allocation region, while other threads
155 // are also concurrently trying to allocate into it, we typically
156 // allocate a dummy object at the end of the region to ensure that
157 // no more allocations can take place in it. However, sometimes we
158 // want to know where the end of the last "real" object we allocated
159 // into the region was and this is what this keeps track.
160 HeapWord* _pre_dummy_top;
161
162 public:
163 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be
164 // assumed to contain zeros.
165 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
166 MemRegion mr, bool is_zeroed = false);
167
168 void set_bottom(HeapWord* value);
169 void set_end(HeapWord* value);
170
171 virtual HeapWord* saved_mark_word() const;
172 virtual void set_saved_mark();
173 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
174
175 // See the comment above in the declaration of _pre_dummy_top for an
176 // explanation of what it is.
177 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
178 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
179 _pre_dummy_top = pre_dummy_top;
180 }
181 HeapWord* pre_dummy_top() {
182 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
183 }
184 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
185
186 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
187 virtual void clear(bool mangle_space);
188
189 HeapWord* block_start(const void* p);
190 HeapWord* block_start_const(const void* p) const;
191
192 // Add offset table update.
193 virtual HeapWord* allocate(size_t word_size);
194 HeapWord* par_allocate(size_t word_size);
195
196 // MarkSweep support phase3
197 virtual HeapWord* initialize_threshold();
198 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
199
200 virtual void print() const;
201
202 void reset_bot() {
203 _offsets.zero_bottom_entry();
204 _offsets.initialize_threshold();
205 }
206
207 void update_bot_for_object(HeapWord* start, size_t word_size) {
208 _offsets.alloc_block(start, word_size);
209 }
210
211 void print_bot_on(outputStream* out) {
212 _offsets.print_on(out);
213 }
214 };
215
216 class HeapRegion: public G1OffsetTableContigSpace {
217 friend class VMStructs;
218 private:
219
220 enum HumongousType {
221 NotHumongous = 0,
222 StartsHumongous,
223 ContinuesHumongous
224 };
225
226 // The next filter kind that should be used for a "new_dcto_cl" call with
227 // the "traditional" signature.
228 HeapRegionDCTOC::FilterKind _next_fk;
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, OopClosure* 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 size_t _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 // See "sort_index" method. -1 means is not in the array.
287 int _sort_index;
288
289 // <PREDICTION>
290 double _gc_efficiency;
291 // </PREDICTION>
292
293 enum YoungType {
294 NotYoung, // a region is not young
295 Young, // a region is young
296 Survivor // a region is young and it contains survivors
297 };
298
299 volatile YoungType _young_type;
300 int _young_index_in_cset;
301 SurvRateGroup* _surv_rate_group;
302 int _age_index;
303
304 // The start of the unmarked area. The unmarked area extends from this
305 // word until the top and/or end of the region, and is the part
306 // of the region for which no marking was done, i.e. objects may
307 // have been allocated in this part since the last mark phase.
308 // "prev" is the top at the start of the last completed marking.
309 // "next" is the top at the start of the in-progress marking (if any.)
310 HeapWord* _prev_top_at_mark_start;
311 HeapWord* _next_top_at_mark_start;
312 // If a collection pause is in progress, this is the top at the start
313 // of that pause.
314
315 // We've counted the marked bytes of objects below here.
316 HeapWord* _top_at_conc_mark_count;
317
318 void init_top_at_mark_start() {
319 assert(_prev_marked_bytes == 0 &&
320 _next_marked_bytes == 0,
321 "Must be called after zero_marked_bytes.");
322 HeapWord* bot = bottom();
323 _prev_top_at_mark_start = bot;
324 _next_top_at_mark_start = bot;
325 _top_at_conc_mark_count = bot;
326 }
327
328 void set_young_type(YoungType new_type) {
329 //assert(_young_type != new_type, "setting the same type" );
330 // TODO: add more assertions here
331 _young_type = new_type;
332 }
333
334 // Cached attributes used in the collection set policy information
335
336 // The RSet length that was added to the total value
337 // for the collection set.
338 size_t _recorded_rs_length;
339
340 // The predicted elapsed time that was added to total value
341 // for the collection set.
342 double _predicted_elapsed_time_ms;
343
344 // The predicted number of bytes to copy that was added to
345 // the total value for the collection set.
346 size_t _predicted_bytes_to_copy;
347
348 public:
349 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros.
350 HeapRegion(size_t hrs_index,
351 G1BlockOffsetSharedArray* sharedOffsetArray,
352 MemRegion mr, bool is_zeroed);
353
354 static int LogOfHRGrainBytes;
355 static int LogOfHRGrainWords;
356 // The normal type of these should be size_t. However, they used to
357 // be members of an enum before and they are assumed by the
358 // compilers to be ints. To avoid going and fixing all their uses,
359 // I'm declaring them as ints. I'm not anticipating heap region
360 // sizes to reach anywhere near 2g, so using an int here is safe.
361 static int GrainBytes;
362 static int GrainWords;
363 static int CardsPerRegion;
364
365 // It sets up the heap region size (GrainBytes / GrainWords), as
366 // well as other related fields that are based on the heap region
367 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
368 // CardsPerRegion). All those fields are considered constant
369 // throughout the JVM's execution, therefore they should only be set
370 // up once during initialization time.
371 static void setup_heap_region_size(uintx min_heap_size);
372
373 enum ClaimValues {
374 InitialClaimValue = 0,
375 FinalCountClaimValue = 1,
376 NoteEndClaimValue = 2,
377 ScrubRemSetClaimValue = 3,
378 ParVerifyClaimValue = 4,
379 RebuildRSClaimValue = 5
380 };
381
382 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
383 assert(is_young(), "we can only skip BOT updates on young regions");
384 return ContiguousSpace::par_allocate(word_size);
385 }
386 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
387 assert(is_young(), "we can only skip BOT updates on young regions");
388 return ContiguousSpace::allocate(word_size);
389 }
390
391 // If this region is a member of a HeapRegionSeq, the index in that
392 // sequence, otherwise -1.
393 size_t hrs_index() const { return _hrs_index; }
394
395 // The number of bytes marked live in the region in the last marking phase.
396 size_t marked_bytes() { return _prev_marked_bytes; }
397 size_t live_bytes() {
398 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
399 }
400
401 // The number of bytes counted in the next marking.
402 size_t next_marked_bytes() { return _next_marked_bytes; }
403 // The number of bytes live wrt the next marking.
404 size_t next_live_bytes() {
405 return
406 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
407 }
408
409 // A lower bound on the amount of garbage bytes in the region.
410 size_t garbage_bytes() {
411 size_t used_at_mark_start_bytes =
412 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
413 assert(used_at_mark_start_bytes >= marked_bytes(),
414 "Can't mark more than we have.");
415 return used_at_mark_start_bytes - marked_bytes();
416 }
417
418 // An upper bound on the number of live bytes in the region.
419 size_t max_live_bytes() { return used() - garbage_bytes(); }
420
421 void add_to_marked_bytes(size_t incr_bytes) {
422 _next_marked_bytes = _next_marked_bytes + incr_bytes;
423 guarantee( _next_marked_bytes <= used(), "invariant" );
424 }
425
426 void zero_marked_bytes() {
427 _prev_marked_bytes = _next_marked_bytes = 0;
428 }
429
430 bool isHumongous() const { return _humongous_type != NotHumongous; }
431 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
432 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
433 // For a humongous region, region in which it starts.
434 HeapRegion* humongous_start_region() const {
435 return _humongous_start_region;
436 }
437
438 // Makes the current region be a "starts humongous" region, i.e.,
439 // the first region in a series of one or more contiguous regions
440 // that will contain a single "humongous" object. The two parameters
441 // are as follows:
442 //
443 // new_top : The new value of the top field of this region which
444 // points to the end of the humongous object that's being
445 // allocated. If there is more than one region in the series, top
446 // will lie beyond this region's original end field and on the last
447 // region in the series.
448 //
449 // new_end : The new value of the end field of this region which
450 // points to the end of the last region in the series. If there is
451 // one region in the series (namely: this one) end will be the same
452 // as the original end of this region.
453 //
454 // Updating top and end as described above makes this region look as
455 // if it spans the entire space taken up by all the regions in the
456 // series and an single allocation moved its top to new_top. This
457 // ensures that the space (capacity / allocated) taken up by all
458 // humongous regions can be calculated by just looking at the
459 // "starts humongous" regions and by ignoring the "continues
460 // humongous" regions.
461 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
462
463 // Makes the current region be a "continues humongous'
464 // region. first_hr is the "start humongous" region of the series
465 // which this region will be part of.
466 void set_continuesHumongous(HeapRegion* first_hr);
467
468 // Unsets the humongous-related fields on the region.
469 void set_notHumongous();
470
471 // If the region has a remembered set, return a pointer to it.
472 HeapRegionRemSet* rem_set() const {
473 return _rem_set;
474 }
475
476 // True iff the region is in current collection_set.
477 bool in_collection_set() const {
478 return _in_collection_set;
479 }
480 void set_in_collection_set(bool b) {
481 _in_collection_set = b;
482 }
483 HeapRegion* next_in_collection_set() {
484 assert(in_collection_set(), "should only invoke on member of CS.");
485 assert(_next_in_special_set == NULL ||
486 _next_in_special_set->in_collection_set(),
487 "Malformed CS.");
488 return _next_in_special_set;
489 }
490 void set_next_in_collection_set(HeapRegion* r) {
491 assert(in_collection_set(), "should only invoke on member of CS.");
492 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
493 _next_in_special_set = r;
494 }
495
496 // Methods used by the HeapRegionSetBase class and subclasses.
497
498 // Getter and setter for the next field used to link regions into
499 // linked lists.
500 HeapRegion* next() { return _next; }
501
502 void set_next(HeapRegion* next) { _next = next; }
503
504 // Every region added to a set is tagged with a reference to that
505 // set. This is used for doing consistency checking to make sure that
506 // the contents of a set are as they should be and it's only
507 // available in non-product builds.
508 #ifdef ASSERT
509 void set_containing_set(HeapRegionSetBase* containing_set) {
510 assert((containing_set == NULL && _containing_set != NULL) ||
511 (containing_set != NULL && _containing_set == NULL),
512 err_msg("containing_set: "PTR_FORMAT" "
513 "_containing_set: "PTR_FORMAT,
514 containing_set, _containing_set));
515
516 _containing_set = containing_set;
517 }
518
519 HeapRegionSetBase* containing_set() { return _containing_set; }
520 #else // ASSERT
521 void set_containing_set(HeapRegionSetBase* containing_set) { }
522
523 // containing_set() is only used in asserts so there's no reason
524 // to provide a dummy version of it.
525 #endif // ASSERT
526
527 // If we want to remove regions from a list in bulk we can simply tag
528 // them with the pending_removal tag and call the
529 // remove_all_pending() method on the list.
530
531 bool pending_removal() { return _pending_removal; }
532
533 void set_pending_removal(bool pending_removal) {
534 if (pending_removal) {
535 assert(!_pending_removal && containing_set() != NULL,
536 "can only set pending removal to true if it's false and "
537 "the region belongs to a region set");
538 } else {
539 assert( _pending_removal && containing_set() == NULL,
540 "can only set pending removal to false if it's true and "
541 "the region does not belong to a region set");
542 }
543
544 _pending_removal = pending_removal;
545 }
546
547 HeapRegion* get_next_young_region() { return _next_young_region; }
548 void set_next_young_region(HeapRegion* hr) {
549 _next_young_region = hr;
550 }
551
552 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
553 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
554 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
555 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
556
557 HeapWord* orig_end() { return _orig_end; }
558
559 // Allows logical separation between objects allocated before and after.
560 void save_marks();
561
562 // Reset HR stuff to default values.
563 void hr_clear(bool par, bool clear_space);
564 void par_clear();
565
566 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
567
568 // Get the start of the unmarked area in this region.
569 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
570 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
571
572 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
573 // allocated in the current region before the last call to "save_mark".
574 void oop_before_save_marks_iterate(OopClosure* cl);
575
576 // This call determines the "filter kind" argument that will be used for
577 // the next call to "new_dcto_cl" on this region with the "traditional"
578 // signature (i.e., the call below.) The default, in the absence of a
579 // preceding call to this method, is "NoFilterKind", and a call to this
580 // method is necessary for each such call, or else it reverts to the
581 // default.
582 // (This is really ugly, but all other methods I could think of changed a
583 // lot of main-line code for G1.)
584 void set_next_filter_kind(HeapRegionDCTOC::FilterKind nfk) {
585 _next_fk = nfk;
586 }
587
588 DirtyCardToOopClosure*
589 new_dcto_closure(OopClosure* cl,
590 CardTableModRefBS::PrecisionStyle precision,
591 HeapRegionDCTOC::FilterKind fk);
592
593 #if WHASSUP
594 DirtyCardToOopClosure*
595 new_dcto_closure(OopClosure* cl,
596 CardTableModRefBS::PrecisionStyle precision,
597 HeapWord* boundary) {
598 assert(boundary == NULL, "This arg doesn't make sense here.");
599 DirtyCardToOopClosure* res = new_dcto_closure(cl, precision, _next_fk);
600 _next_fk = HeapRegionDCTOC::NoFilterKind;
601 return res;
602 }
603 #endif
604
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
611 // Note the start of a marking phase. Record the
612 // start of the unmarked area of the region here.
613 void note_start_of_marking(bool during_initial_mark) {
614 init_top_at_conc_mark_count();
615 _next_marked_bytes = 0;
616 if (during_initial_mark && is_young() && !is_survivor())
617 _next_top_at_mark_start = bottom();
618 else
619 _next_top_at_mark_start = top();
620 }
621
622 // Note the end of a marking phase. Install the start of
623 // the unmarked area that was captured at start of marking.
624 void note_end_of_marking() {
625 _prev_top_at_mark_start = _next_top_at_mark_start;
626 _prev_marked_bytes = _next_marked_bytes;
627 _next_marked_bytes = 0;
628
629 guarantee(_prev_marked_bytes <=
630 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize,
631 "invariant");
632 }
633
634 // After an evacuation, we need to update _next_top_at_mark_start
635 // to be the current top. Note this is only valid if we have only
636 // ever evacuated into this region. If we evacuate, allocate, and
637 // then evacuate we are in deep doodoo.
638 void note_end_of_copying() {
639 assert(top() >= _next_top_at_mark_start, "Increase only");
640 _next_top_at_mark_start = top();
641 }
642
643 // Returns "false" iff no object in the region was allocated when the
644 // last mark phase ended.
645 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
646
647 // If "is_marked()" is true, then this is the index of the region in
648 // an array constructed at the end of marking of the regions in a
649 // "desirability" order.
650 int sort_index() {
651 return _sort_index;
652 }
653 void set_sort_index(int i) {
654 _sort_index = i;
655 }
656
657 void init_top_at_conc_mark_count() {
658 _top_at_conc_mark_count = bottom();
659 }
660
661 void set_top_at_conc_mark_count(HeapWord *cur) {
662 assert(bottom() <= cur && cur <= end(), "Sanity.");
663 _top_at_conc_mark_count = cur;
664 }
665
666 HeapWord* top_at_conc_mark_count() {
667 return _top_at_conc_mark_count;
668 }
669
670 void reset_during_compaction() {
671 guarantee( isHumongous() && startsHumongous(),
672 "should only be called for humongous regions");
673
674 zero_marked_bytes();
675 init_top_at_mark_start();
676 }
677
678 // <PREDICTION>
679 void calc_gc_efficiency(void);
680 double gc_efficiency() { return _gc_efficiency;}
681 // </PREDICTION>
682
683 bool is_young() const { return _young_type != NotYoung; }
684 bool is_survivor() const { return _young_type == Survivor; }
685
686 int young_index_in_cset() const { return _young_index_in_cset; }
687 void set_young_index_in_cset(int index) {
688 assert( (index == -1) || is_young(), "pre-condition" );
689 _young_index_in_cset = index;
690 }
691
692 int age_in_surv_rate_group() {
693 assert( _surv_rate_group != NULL, "pre-condition" );
694 assert( _age_index > -1, "pre-condition" );
695 return _surv_rate_group->age_in_group(_age_index);
696 }
697
698 void record_surv_words_in_group(size_t words_survived) {
699 assert( _surv_rate_group != NULL, "pre-condition" );
700 assert( _age_index > -1, "pre-condition" );
701 int age_in_group = age_in_surv_rate_group();
702 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
703 }
704
705 int age_in_surv_rate_group_cond() {
706 if (_surv_rate_group != NULL)
707 return age_in_surv_rate_group();
708 else
709 return -1;
710 }
711
712 SurvRateGroup* surv_rate_group() {
713 return _surv_rate_group;
714 }
715
716 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
717 assert( surv_rate_group != NULL, "pre-condition" );
718 assert( _surv_rate_group == NULL, "pre-condition" );
719 assert( is_young(), "pre-condition" );
720
721 _surv_rate_group = surv_rate_group;
722 _age_index = surv_rate_group->next_age_index();
723 }
724
725 void uninstall_surv_rate_group() {
726 if (_surv_rate_group != NULL) {
727 assert( _age_index > -1, "pre-condition" );
728 assert( is_young(), "pre-condition" );
729
730 _surv_rate_group = NULL;
731 _age_index = -1;
732 } else {
733 assert( _age_index == -1, "pre-condition" );
734 }
735 }
736
737 void set_young() { set_young_type(Young); }
738
739 void set_survivor() { set_young_type(Survivor); }
740
741 void set_not_young() { set_young_type(NotYoung); }
742
743 // Determine if an object has been allocated since the last
744 // mark performed by the collector. This returns true iff the object
745 // is within the unmarked area of the region.
746 bool obj_allocated_since_prev_marking(oop obj) const {
747 return (HeapWord *) obj >= prev_top_at_mark_start();
748 }
749 bool obj_allocated_since_next_marking(oop obj) const {
750 return (HeapWord *) obj >= next_top_at_mark_start();
751 }
752
753 // For parallel heapRegion traversal.
754 bool claimHeapRegion(int claimValue);
755 jint claim_value() { return _claimed; }
756 // Use this carefully: only when you're sure no one is claiming...
757 void set_claim_value(int claimValue) { _claimed = claimValue; }
758
759 // Returns the "evacuation_failed" property of the region.
760 bool evacuation_failed() { return _evacuation_failed; }
761
762 // Sets the "evacuation_failed" property of the region.
763 void set_evacuation_failed(bool b) {
764 _evacuation_failed = b;
765
766 if (b) {
767 init_top_at_conc_mark_count();
768 _next_marked_bytes = 0;
769 }
770 }
771
772 // Requires that "mr" be entirely within the region.
773 // Apply "cl->do_object" to all objects that intersect with "mr".
774 // If the iteration encounters an unparseable portion of the region,
775 // or if "cl->abort()" is true after a closure application,
776 // terminate the iteration and return the address of the start of the
777 // subregion that isn't done. (The two can be distinguished by querying
778 // "cl->abort()".) Return of "NULL" indicates that the iteration
779 // completed.
780 HeapWord*
781 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
782
783 // filter_young: if true and the region is a young region then we
784 // skip the iteration.
785 // card_ptr: if not NULL, and we decide that the card is not young
786 // and we iterate over it, we'll clean the card before we start the
787 // iteration.
788 HeapWord*
789 oops_on_card_seq_iterate_careful(MemRegion mr,
790 FilterOutOfRegionClosure* cl,
791 bool filter_young,
792 jbyte* card_ptr);
793
794 // A version of block start that is guaranteed to find *some* block
795 // boundary at or before "p", but does not object iteration, and may
796 // therefore be used safely when the heap is unparseable.
797 HeapWord* block_start_careful(const void* p) const {
798 return _offsets.block_start_careful(p);
799 }
800
801 // Requires that "addr" is within the region. Returns the start of the
802 // first ("careful") block that starts at or after "addr", or else the
803 // "end" of the region if there is no such block.
804 HeapWord* next_block_start_careful(HeapWord* addr);
805
806 size_t recorded_rs_length() const { return _recorded_rs_length; }
807 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
808 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
809
810 void set_recorded_rs_length(size_t rs_length) {
811 _recorded_rs_length = rs_length;
812 }
813
814 void set_predicted_elapsed_time_ms(double ms) {
815 _predicted_elapsed_time_ms = ms;
816 }
817
818 void set_predicted_bytes_to_copy(size_t bytes) {
819 _predicted_bytes_to_copy = bytes;
820 }
821
822 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
823 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
824 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
825
826 CompactibleSpace* next_compaction_space() const;
827
828 virtual void reset_after_compaction();
829
830 void print() const;
831 void print_on(outputStream* st) const;
832
833 // vo == UsePrevMarking -> use "prev" marking information,
834 // vo == UseNextMarking -> use "next" marking information
835 // vo == UseMarkWord -> use the mark word in the object header
836 //
837 // NOTE: Only the "prev" marking information is guaranteed to be
838 // consistent most of the time, so most calls to this should use
839 // vo == UsePrevMarking.
840 // Currently, there is only one case where this is called with
841 // vo == UseNextMarking, which is to verify the "next" marking
842 // information at the end of remark.
843 // Currently there is only one place where this is called with
844 // vo == UseMarkWord, which is to verify the marking during a
845 // full GC.
846 void verify(bool allow_dirty, VerifyOption vo, bool *failures) const;
847
848 // Override; it uses the "prev" marking information
849 virtual void verify(bool allow_dirty) const;
850 };
851
852 // HeapRegionClosure is used for iterating over regions.
853 // Terminates the iteration when the "doHeapRegion" method returns "true".
854 class HeapRegionClosure : public StackObj {
855 friend class HeapRegionSeq;
856 friend class G1CollectedHeap;
857
858 bool _complete;
859 void incomplete() { _complete = false; }
860
861 public:
862 HeapRegionClosure(): _complete(true) {}
863
864 // Typically called on each region until it returns true.
865 virtual bool doHeapRegion(HeapRegion* r) = 0;
866
867 // True after iteration if the closure was applied to all heap regions
868 // and returned "false" in all cases.
869 bool complete() { return _complete; }
870 };
871
872 #endif // SERIALGC
873
874 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP