1 /*
2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
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 // The complicating factor is that BlockOffsetTable diverged
122 // significantly, and we need functionality that is only in the G1 version.
123 // So I copied that code, which led to an alternate G1 version of
124 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
125 // be reconciled, then G1OffsetTableContigSpace could go away.
126
127 // The idea behind time stamps is the following. Doing a save_marks on
128 // all regions at every GC pause is time consuming (if I remember
129 // well, 10ms or so). So, we would like to do that only for regions
130 // that are GC alloc regions. To achieve this, we use time
131 // stamps. For every evacuation pause, G1CollectedHeap generates a
132 // unique time stamp (essentially a counter that gets
133 // incremented). Every time we want to call save_marks on a region,
134 // we set the saved_mark_word to top and also copy the current GC
135 // time stamp to the time stamp field of the space. Reading the
136 // saved_mark_word involves checking the time stamp of the
137 // region. If it is the same as the current GC time stamp, then we
138 // can safely read the saved_mark_word field, as it is valid. If the
139 // time stamp of the region is not the same as the current GC time
140 // stamp, then we instead read top, as the saved_mark_word field is
141 // invalid. Time stamps (on the regions and also on the
142 // G1CollectedHeap) are reset at every cleanup (we iterate over
143 // the regions anyway) and at the end of a Full GC. The current scheme
144 // that uses sequential unsigned ints will fail only if we have 4b
145 // evacuation pauses between two cleanups, which is _highly_ unlikely.
146
147 class G1OffsetTableContigSpace: public ContiguousSpace {
148 friend class VMStructs;
149 protected:
150 G1BlockOffsetArrayContigSpace _offsets;
151 Mutex _par_alloc_lock;
152 volatile unsigned _gc_time_stamp;
153 // When we need to retire an allocation region, while other threads
154 // are also concurrently trying to allocate into it, we typically
155 // allocate a dummy object at the end of the region to ensure that
156 // no more allocations can take place in it. However, sometimes we
157 // want to know where the end of the last "real" object we allocated
158 // into the region was and this is what this keeps track.
159 HeapWord* _pre_dummy_top;
160
161 public:
162 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be
163 // assumed to contain zeros.
164 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
165 MemRegion mr, bool is_zeroed = false);
166
167 void set_bottom(HeapWord* value);
168 void set_end(HeapWord* value);
169
170 virtual HeapWord* saved_mark_word() const;
171 virtual void set_saved_mark();
172 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
173
174 // See the comment above in the declaration of _pre_dummy_top for an
175 // explanation of what it is.
176 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
177 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
178 _pre_dummy_top = pre_dummy_top;
179 }
180 HeapWord* pre_dummy_top() {
181 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
182 }
183 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
184
185 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
186 virtual void clear(bool mangle_space);
187
188 HeapWord* block_start(const void* p);
189 HeapWord* block_start_const(const void* p) const;
190
191 // Add offset table update.
192 virtual HeapWord* allocate(size_t word_size);
193 HeapWord* par_allocate(size_t word_size);
194
195 // MarkSweep support phase3
196 virtual HeapWord* initialize_threshold();
197 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
198
199 virtual void print() const;
200
201 void reset_bot() {
202 _offsets.zero_bottom_entry();
203 _offsets.initialize_threshold();
204 }
205
206 void update_bot_for_object(HeapWord* start, size_t word_size) {
207 _offsets.alloc_block(start, word_size);
208 }
209
210 void print_bot_on(outputStream* out) {
211 _offsets.print_on(out);
212 }
213 };
214
215 class HeapRegion: public G1OffsetTableContigSpace {
216 friend class VMStructs;
217 private:
218
219 enum HumongousType {
220 NotHumongous = 0,
221 StartsHumongous,
222 ContinuesHumongous
223 };
224
225 // Requires that the region "mr" be dense with objects, and begin and end
226 // with an object.
227 void oops_in_mr_iterate(MemRegion mr, OopClosure* cl);
228
229 // The remembered set for this region.
230 // (Might want to make this "inline" later, to avoid some alloc failure
231 // issues.)
232 HeapRegionRemSet* _rem_set;
233
234 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
235
236 protected:
237 // The index of this region in the heap region sequence.
238 size_t _hrs_index;
239
240 HumongousType _humongous_type;
241 // For a humongous region, region in which it starts.
242 HeapRegion* _humongous_start_region;
243 // For the start region of a humongous sequence, it's original end().
244 HeapWord* _orig_end;
245
246 // True iff the region is in current collection_set.
247 bool _in_collection_set;
248
249 // True iff an attempt to evacuate an object in the region failed.
250 bool _evacuation_failed;
251
252 // A heap region may be a member one of a number of special subsets, each
253 // represented as linked lists through the field below. Currently, these
254 // sets include:
255 // The collection set.
256 // The set of allocation regions used in a collection pause.
257 // Spaces that may contain gray objects.
258 HeapRegion* _next_in_special_set;
259
260 // next region in the young "generation" region set
261 HeapRegion* _next_young_region;
262
263 // Next region whose cards need cleaning
264 HeapRegion* _next_dirty_cards_region;
265
266 // Fields used by the HeapRegionSetBase class and subclasses.
267 HeapRegion* _next;
268 #ifdef ASSERT
269 HeapRegionSetBase* _containing_set;
270 #endif // ASSERT
271 bool _pending_removal;
272
273 // For parallel heapRegion traversal.
274 jint _claimed;
275
276 // We use concurrent marking to determine the amount of live data
277 // in each heap region.
278 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
279 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
280
281 // See "sort_index" method. -1 means is not in the array.
282 int _sort_index;
283
284 // <PREDICTION>
285 double _gc_efficiency;
286 // </PREDICTION>
287
288 enum YoungType {
289 NotYoung, // a region is not young
290 Young, // a region is young
291 Survivor // a region is young and it contains survivors
292 };
293
294 volatile YoungType _young_type;
295 int _young_index_in_cset;
296 SurvRateGroup* _surv_rate_group;
297 int _age_index;
298
299 // The start of the unmarked area. The unmarked area extends from this
300 // word until the top and/or end of the region, and is the part
301 // of the region for which no marking was done, i.e. objects may
302 // have been allocated in this part since the last mark phase.
303 // "prev" is the top at the start of the last completed marking.
304 // "next" is the top at the start of the in-progress marking (if any.)
305 HeapWord* _prev_top_at_mark_start;
306 HeapWord* _next_top_at_mark_start;
307 // If a collection pause is in progress, this is the top at the start
308 // of that pause.
309
310 // We've counted the marked bytes of objects below here.
311 HeapWord* _top_at_conc_mark_count;
312
313 void init_top_at_mark_start() {
314 assert(_prev_marked_bytes == 0 &&
315 _next_marked_bytes == 0,
316 "Must be called after zero_marked_bytes.");
317 HeapWord* bot = bottom();
318 _prev_top_at_mark_start = bot;
319 _next_top_at_mark_start = bot;
320 _top_at_conc_mark_count = bot;
321 }
322
323 void set_young_type(YoungType new_type) {
324 //assert(_young_type != new_type, "setting the same type" );
325 // TODO: add more assertions here
326 _young_type = new_type;
327 }
328
329 // Cached attributes used in the collection set policy information
330
331 // The RSet length that was added to the total value
332 // for the collection set.
333 size_t _recorded_rs_length;
334
335 // The predicted elapsed time that was added to total value
336 // for the collection set.
337 double _predicted_elapsed_time_ms;
338
339 // The predicted number of bytes to copy that was added to
340 // the total value for the collection set.
341 size_t _predicted_bytes_to_copy;
342
343 public:
344 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros.
345 HeapRegion(size_t hrs_index,
346 G1BlockOffsetSharedArray* sharedOffsetArray,
347 MemRegion mr, bool is_zeroed);
348
349 static int LogOfHRGrainBytes;
350 static int LogOfHRGrainWords;
351
352 static size_t GrainBytes;
353 static size_t GrainWords;
354 static size_t CardsPerRegion;
355
356 static size_t align_up_to_region_byte_size(size_t sz) {
357 return (sz + (size_t) GrainBytes - 1) &
358 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
359 }
360
361 // It sets up the heap region size (GrainBytes / GrainWords), as
362 // well as other related fields that are based on the heap region
363 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
364 // CardsPerRegion). All those fields are considered constant
365 // throughout the JVM's execution, therefore they should only be set
366 // up once during initialization time.
367 static void setup_heap_region_size(uintx min_heap_size);
368
369 enum ClaimValues {
370 InitialClaimValue = 0,
371 FinalCountClaimValue = 1,
372 NoteEndClaimValue = 2,
373 ScrubRemSetClaimValue = 3,
374 ParVerifyClaimValue = 4,
375 RebuildRSClaimValue = 5
376 };
377
378 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
379 assert(is_young(), "we can only skip BOT updates on young regions");
380 return ContiguousSpace::par_allocate(word_size);
381 }
382 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
383 assert(is_young(), "we can only skip BOT updates on young regions");
384 return ContiguousSpace::allocate(word_size);
385 }
386
387 // If this region is a member of a HeapRegionSeq, the index in that
388 // sequence, otherwise -1.
389 size_t hrs_index() const { return _hrs_index; }
390
391 // The number of bytes marked live in the region in the last marking phase.
392 size_t marked_bytes() { return _prev_marked_bytes; }
393 size_t live_bytes() {
394 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
395 }
396
397 // The number of bytes counted in the next marking.
398 size_t next_marked_bytes() { return _next_marked_bytes; }
399 // The number of bytes live wrt the next marking.
400 size_t next_live_bytes() {
401 return
402 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
403 }
404
405 // A lower bound on the amount of garbage bytes in the region.
406 size_t garbage_bytes() {
407 size_t used_at_mark_start_bytes =
408 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
409 assert(used_at_mark_start_bytes >= marked_bytes(),
410 "Can't mark more than we have.");
411 return used_at_mark_start_bytes - marked_bytes();
412 }
413
414 // An upper bound on the number of live bytes in the region.
415 size_t max_live_bytes() { return used() - garbage_bytes(); }
416
417 void add_to_marked_bytes(size_t incr_bytes) {
418 _next_marked_bytes = _next_marked_bytes + incr_bytes;
419 guarantee( _next_marked_bytes <= used(), "invariant" );
420 }
421
422 void zero_marked_bytes() {
423 _prev_marked_bytes = _next_marked_bytes = 0;
424 }
425
426 bool isHumongous() const { return _humongous_type != NotHumongous; }
427 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
428 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
429 // For a humongous region, region in which it starts.
430 HeapRegion* humongous_start_region() const {
431 return _humongous_start_region;
432 }
433
434 // Same as Space::is_in_reserved, but will use the original size of a region.
435 // The original size and the current size only differ for start humongous
436 // regions. They get their _end set up to be the end of the last continues
437 // region of the corresponding humongous object.
438 bool is_in_reserved_raw(const void* p) const {
439 return _bottom <= p && p < _orig_end;
440 }
441
442 // Makes the current region be a "starts humongous" region, i.e.,
443 // the first region in a series of one or more contiguous regions
444 // that will contain a single "humongous" object. The two parameters
445 // are as follows:
446 //
447 // new_top : The new value of the top field of this region which
448 // points to the end of the humongous object that's being
449 // allocated. If there is more than one region in the series, top
450 // will lie beyond this region's original end field and on the last
451 // region in the series.
452 //
453 // new_end : The new value of the end field of this region which
454 // points to the end of the last region in the series. If there is
455 // one region in the series (namely: this one) end will be the same
456 // as the original end of this region.
457 //
458 // Updating top and end as described above makes this region look as
459 // if it spans the entire space taken up by all the regions in the
460 // series and an single allocation moved its top to new_top. This
461 // ensures that the space (capacity / allocated) taken up by all
462 // humongous regions can be calculated by just looking at the
463 // "starts humongous" regions and by ignoring the "continues
464 // humongous" regions.
465 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
466
467 // Makes the current region be a "continues humongous'
468 // region. first_hr is the "start humongous" region of the series
469 // which this region will be part of.
470 void set_continuesHumongous(HeapRegion* first_hr);
471
472 // Unsets the humongous-related fields on the region.
473 void set_notHumongous();
474
475 // If the region has a remembered set, return a pointer to it.
476 HeapRegionRemSet* rem_set() const {
477 return _rem_set;
478 }
479
480 // True iff the region is in current collection_set.
481 bool in_collection_set() const {
482 return _in_collection_set;
483 }
484 void set_in_collection_set(bool b) {
485 _in_collection_set = b;
486 }
487 HeapRegion* next_in_collection_set() {
488 assert(in_collection_set(), "should only invoke on member of CS.");
489 assert(_next_in_special_set == NULL ||
490 _next_in_special_set->in_collection_set(),
491 "Malformed CS.");
492 return _next_in_special_set;
493 }
494 void set_next_in_collection_set(HeapRegion* r) {
495 assert(in_collection_set(), "should only invoke on member of CS.");
496 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
497 _next_in_special_set = r;
498 }
499
500 // Methods used by the HeapRegionSetBase class and subclasses.
501
502 // Getter and setter for the next field used to link regions into
503 // linked lists.
504 HeapRegion* next() { return _next; }
505
506 void set_next(HeapRegion* next) { _next = next; }
507
508 // Every region added to a set is tagged with a reference to that
509 // set. This is used for doing consistency checking to make sure that
510 // the contents of a set are as they should be and it's only
511 // available in non-product builds.
512 #ifdef ASSERT
513 void set_containing_set(HeapRegionSetBase* containing_set) {
514 assert((containing_set == NULL && _containing_set != NULL) ||
515 (containing_set != NULL && _containing_set == NULL),
516 err_msg("containing_set: "PTR_FORMAT" "
517 "_containing_set: "PTR_FORMAT,
518 containing_set, _containing_set));
519
520 _containing_set = containing_set;
521 }
522
523 HeapRegionSetBase* containing_set() { return _containing_set; }
524 #else // ASSERT
525 void set_containing_set(HeapRegionSetBase* containing_set) { }
526
527 // containing_set() is only used in asserts so there's no reason
528 // to provide a dummy version of it.
529 #endif // ASSERT
530
531 // If we want to remove regions from a list in bulk we can simply tag
532 // them with the pending_removal tag and call the
533 // remove_all_pending() method on the list.
534
535 bool pending_removal() { return _pending_removal; }
536
537 void set_pending_removal(bool pending_removal) {
538 if (pending_removal) {
539 assert(!_pending_removal && containing_set() != NULL,
540 "can only set pending removal to true if it's false and "
541 "the region belongs to a region set");
542 } else {
543 assert( _pending_removal && containing_set() == NULL,
544 "can only set pending removal to false if it's true and "
545 "the region does not belong to a region set");
546 }
547
548 _pending_removal = pending_removal;
549 }
550
551 HeapRegion* get_next_young_region() { return _next_young_region; }
552 void set_next_young_region(HeapRegion* hr) {
553 _next_young_region = hr;
554 }
555
556 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
557 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
558 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
559 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
560
561 HeapWord* orig_end() { return _orig_end; }
562
563 // Allows logical separation between objects allocated before and after.
564 void save_marks();
565
566 // Reset HR stuff to default values.
567 void hr_clear(bool par, bool clear_space);
568 void par_clear();
569
570 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
571
572 // Get the start of the unmarked area in this region.
573 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
574 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
575
576 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
577 // allocated in the current region before the last call to "save_mark".
578 void oop_before_save_marks_iterate(OopClosure* cl);
579
580 DirtyCardToOopClosure*
581 new_dcto_closure(OopClosure* cl,
582 CardTableModRefBS::PrecisionStyle precision,
583 HeapRegionDCTOC::FilterKind fk);
584
585 // Note the start or end of marking. This tells the heap region
586 // that the collector is about to start or has finished (concurrently)
587 // marking the heap.
588
589 // Note the start of a marking phase. Record the
590 // start of the unmarked area of the region here.
591 void note_start_of_marking(bool during_initial_mark) {
592 init_top_at_conc_mark_count();
593 _next_marked_bytes = 0;
594 if (during_initial_mark && is_young() && !is_survivor())
595 _next_top_at_mark_start = bottom();
596 else
597 _next_top_at_mark_start = top();
598 }
599
600 // Note the end of a marking phase. Install the start of
601 // the unmarked area that was captured at start of marking.
602 void note_end_of_marking() {
603 _prev_top_at_mark_start = _next_top_at_mark_start;
604 _prev_marked_bytes = _next_marked_bytes;
605 _next_marked_bytes = 0;
606
607 guarantee(_prev_marked_bytes <=
608 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize,
609 "invariant");
610 }
611
612 // After an evacuation, we need to update _next_top_at_mark_start
613 // to be the current top. Note this is only valid if we have only
614 // ever evacuated into this region. If we evacuate, allocate, and
615 // then evacuate we are in deep doodoo.
616 void note_end_of_copying() {
617 assert(top() >= _next_top_at_mark_start, "Increase only");
618 _next_top_at_mark_start = top();
619 }
620
621 // Returns "false" iff no object in the region was allocated when the
622 // last mark phase ended.
623 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
624
625 // If "is_marked()" is true, then this is the index of the region in
626 // an array constructed at the end of marking of the regions in a
627 // "desirability" order.
628 int sort_index() {
629 return _sort_index;
630 }
631 void set_sort_index(int i) {
632 _sort_index = i;
633 }
634
635 void init_top_at_conc_mark_count() {
636 _top_at_conc_mark_count = bottom();
637 }
638
639 void set_top_at_conc_mark_count(HeapWord *cur) {
640 assert(bottom() <= cur && cur <= end(), "Sanity.");
641 _top_at_conc_mark_count = cur;
642 }
643
644 HeapWord* top_at_conc_mark_count() {
645 return _top_at_conc_mark_count;
646 }
647
648 void reset_during_compaction() {
649 guarantee( isHumongous() && startsHumongous(),
650 "should only be called for humongous regions");
651
652 zero_marked_bytes();
653 init_top_at_mark_start();
654 }
655
656 // <PREDICTION>
657 void calc_gc_efficiency(void);
658 double gc_efficiency() { return _gc_efficiency;}
659 // </PREDICTION>
660
661 bool is_young() const { return _young_type != NotYoung; }
662 bool is_survivor() const { return _young_type == Survivor; }
663
664 int young_index_in_cset() const { return _young_index_in_cset; }
665 void set_young_index_in_cset(int index) {
666 assert( (index == -1) || is_young(), "pre-condition" );
667 _young_index_in_cset = index;
668 }
669
670 int age_in_surv_rate_group() {
671 assert( _surv_rate_group != NULL, "pre-condition" );
672 assert( _age_index > -1, "pre-condition" );
673 return _surv_rate_group->age_in_group(_age_index);
674 }
675
676 void record_surv_words_in_group(size_t words_survived) {
677 assert( _surv_rate_group != NULL, "pre-condition" );
678 assert( _age_index > -1, "pre-condition" );
679 int age_in_group = age_in_surv_rate_group();
680 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
681 }
682
683 int age_in_surv_rate_group_cond() {
684 if (_surv_rate_group != NULL)
685 return age_in_surv_rate_group();
686 else
687 return -1;
688 }
689
690 SurvRateGroup* surv_rate_group() {
691 return _surv_rate_group;
692 }
693
694 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
695 assert( surv_rate_group != NULL, "pre-condition" );
696 assert( _surv_rate_group == NULL, "pre-condition" );
697 assert( is_young(), "pre-condition" );
698
699 _surv_rate_group = surv_rate_group;
700 _age_index = surv_rate_group->next_age_index();
701 }
702
703 void uninstall_surv_rate_group() {
704 if (_surv_rate_group != NULL) {
705 assert( _age_index > -1, "pre-condition" );
706 assert( is_young(), "pre-condition" );
707
708 _surv_rate_group = NULL;
709 _age_index = -1;
710 } else {
711 assert( _age_index == -1, "pre-condition" );
712 }
713 }
714
715 void set_young() { set_young_type(Young); }
716
717 void set_survivor() { set_young_type(Survivor); }
718
719 void set_not_young() { set_young_type(NotYoung); }
720
721 // Determine if an object has been allocated since the last
722 // mark performed by the collector. This returns true iff the object
723 // is within the unmarked area of the region.
724 bool obj_allocated_since_prev_marking(oop obj) const {
725 return (HeapWord *) obj >= prev_top_at_mark_start();
726 }
727 bool obj_allocated_since_next_marking(oop obj) const {
728 return (HeapWord *) obj >= next_top_at_mark_start();
729 }
730
731 // For parallel heapRegion traversal.
732 bool claimHeapRegion(int claimValue);
733 jint claim_value() { return _claimed; }
734 // Use this carefully: only when you're sure no one is claiming...
735 void set_claim_value(int claimValue) { _claimed = claimValue; }
736
737 // Returns the "evacuation_failed" property of the region.
738 bool evacuation_failed() { return _evacuation_failed; }
739
740 // Sets the "evacuation_failed" property of the region.
741 void set_evacuation_failed(bool b) {
742 _evacuation_failed = b;
743
744 if (b) {
745 init_top_at_conc_mark_count();
746 _next_marked_bytes = 0;
747 }
748 }
749
750 // Requires that "mr" be entirely within the region.
751 // Apply "cl->do_object" to all objects that intersect with "mr".
752 // If the iteration encounters an unparseable portion of the region,
753 // or if "cl->abort()" is true after a closure application,
754 // terminate the iteration and return the address of the start of the
755 // subregion that isn't done. (The two can be distinguished by querying
756 // "cl->abort()".) Return of "NULL" indicates that the iteration
757 // completed.
758 HeapWord*
759 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
760
761 // filter_young: if true and the region is a young region then we
762 // skip the iteration.
763 // card_ptr: if not NULL, and we decide that the card is not young
764 // and we iterate over it, we'll clean the card before we start the
765 // iteration.
766 HeapWord*
767 oops_on_card_seq_iterate_careful(MemRegion mr,
768 FilterOutOfRegionClosure* cl,
769 bool filter_young,
770 jbyte* card_ptr);
771
772 // A version of block start that is guaranteed to find *some* block
773 // boundary at or before "p", but does not object iteration, and may
774 // therefore be used safely when the heap is unparseable.
775 HeapWord* block_start_careful(const void* p) const {
776 return _offsets.block_start_careful(p);
777 }
778
779 // Requires that "addr" is within the region. Returns the start of the
780 // first ("careful") block that starts at or after "addr", or else the
781 // "end" of the region if there is no such block.
782 HeapWord* next_block_start_careful(HeapWord* addr);
783
784 size_t recorded_rs_length() const { return _recorded_rs_length; }
785 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
786 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
787
788 void set_recorded_rs_length(size_t rs_length) {
789 _recorded_rs_length = rs_length;
790 }
791
792 void set_predicted_elapsed_time_ms(double ms) {
793 _predicted_elapsed_time_ms = ms;
794 }
795
796 void set_predicted_bytes_to_copy(size_t bytes) {
797 _predicted_bytes_to_copy = bytes;
798 }
799
800 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
801 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
802 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
803
804 CompactibleSpace* next_compaction_space() const;
805
806 virtual void reset_after_compaction();
807
808 void print() const;
809 void print_on(outputStream* st) const;
810
811 // vo == UsePrevMarking -> use "prev" marking information,
812 // vo == UseNextMarking -> use "next" marking information
813 // vo == UseMarkWord -> use the mark word in the object header
814 //
815 // NOTE: Only the "prev" marking information is guaranteed to be
816 // consistent most of the time, so most calls to this should use
817 // vo == UsePrevMarking.
818 // Currently, there is only one case where this is called with
819 // vo == UseNextMarking, which is to verify the "next" marking
820 // information at the end of remark.
821 // Currently there is only one place where this is called with
822 // vo == UseMarkWord, which is to verify the marking during a
823 // full GC.
824 void verify(bool allow_dirty, VerifyOption vo, bool *failures) const;
825
826 // Override; it uses the "prev" marking information
827 virtual void verify(bool allow_dirty) const;
828 };
829
830 // HeapRegionClosure is used for iterating over regions.
831 // Terminates the iteration when the "doHeapRegion" method returns "true".
832 class HeapRegionClosure : public StackObj {
833 friend class HeapRegionSeq;
834 friend class G1CollectedHeap;
835
836 bool _complete;
837 void incomplete() { _complete = false; }
838
839 public:
840 HeapRegionClosure(): _complete(true) {}
841
842 // Typically called on each region until it returns true.
843 virtual bool doHeapRegion(HeapRegion* r) = 0;
844
845 // True after iteration if the closure was applied to all heap regions
846 // and returned "false" in all cases.
847 bool complete() { return _complete; }
848 };
849
850 #endif // SERIALGC
851
852 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP