1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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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 "%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_)->startsHumongous() ? "HS" : \
60 (_hr_)->continuesHumongous() ? "HC" : \
61 !(_hr_)->is_empty() ? "O" : "F", \
62 (_hr_)->bottom(), (_hr_)->top(), (_hr_)->end()
63
64 // sentinel value for hrs_index
65 #define G1_NULL_HRS_INDEX ((uint) -1)
66
67 // A dirty card to oop closure for heap regions. It
68 // knows how to get the G1 heap and how to use the bitmap
69 // in the concurrent marker used by G1 to filter remembered
70 // sets.
71
72 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
73 public:
74 // Specification of possible DirtyCardToOopClosure filtering.
75 enum FilterKind {
76 NoFilterKind,
77 IntoCSFilterKind,
78 OutOfRegionFilterKind
79 };
80
81 protected:
82 HeapRegion* _hr;
83 FilterKind _fk;
84 G1CollectedHeap* _g1;
85
86 void walk_mem_region_with_cl(MemRegion mr,
87 HeapWord* bottom, HeapWord* top,
88 ExtendedOopClosure* cl);
89
90 // We don't specialize this for FilteringClosure; filtering is handled by
91 // the "FilterKind" mechanism. But we provide this to avoid a compiler
92 // warning.
93 void walk_mem_region_with_cl(MemRegion mr,
94 HeapWord* bottom, HeapWord* top,
95 FilteringClosure* cl) {
96 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
97 (ExtendedOopClosure*)cl);
98 }
99
100 // Get the actual top of the area on which the closure will
101 // operate, given where the top is assumed to be (the end of the
102 // memory region passed to do_MemRegion) and where the object
103 // at the top is assumed to start. For example, an object may
104 // start at the top but actually extend past the assumed top,
105 // in which case the top becomes the end of the object.
106 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
107 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
108 }
109
110 // Walk the given memory region from bottom to (actual) top
111 // looking for objects and applying the oop closure (_cl) to
112 // them. The base implementation of this treats the area as
113 // blocks, where a block may or may not be an object. Sub-
114 // classes should override this to provide more accurate
115 // or possibly more efficient walking.
116 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) {
117 Filtering_DCTOC::walk_mem_region(mr, bottom, top);
118 }
119
120 public:
121 HeapRegionDCTOC(G1CollectedHeap* g1,
122 HeapRegion* hr, ExtendedOopClosure* cl,
123 CardTableModRefBS::PrecisionStyle precision,
124 FilterKind fk);
125 };
126
127 // The complicating factor is that BlockOffsetTable diverged
128 // significantly, and we need functionality that is only in the G1 version.
129 // So I copied that code, which led to an alternate G1 version of
130 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
131 // be reconciled, then G1OffsetTableContigSpace could go away.
132
133 // The idea behind time stamps is the following. Doing a save_marks on
134 // all regions at every GC pause is time consuming (if I remember
135 // well, 10ms or so). So, we would like to do that only for regions
136 // that are GC alloc regions. To achieve this, we use time
137 // stamps. For every evacuation pause, G1CollectedHeap generates a
138 // unique time stamp (essentially a counter that gets
139 // incremented). Every time we want to call save_marks on a region,
140 // we set the saved_mark_word to top and also copy the current GC
141 // time stamp to the time stamp field of the space. Reading the
142 // saved_mark_word involves checking the time stamp of the
143 // region. If it is the same as the current GC time stamp, then we
144 // can safely read the saved_mark_word field, as it is valid. If the
145 // time stamp of the region is not the same as the current GC time
146 // stamp, then we instead read top, as the saved_mark_word field is
147 // invalid. Time stamps (on the regions and also on the
148 // G1CollectedHeap) are reset at every cleanup (we iterate over
149 // the regions anyway) and at the end of a Full GC. The current scheme
150 // that uses sequential unsigned ints will fail only if we have 4b
151 // evacuation pauses between two cleanups, which is _highly_ unlikely.
152
153 class G1OffsetTableContigSpace: public ContiguousSpace {
154 friend class VMStructs;
155 protected:
156 G1BlockOffsetArrayContigSpace _offsets;
157 Mutex _par_alloc_lock;
158 volatile unsigned _gc_time_stamp;
159 // When we need to retire an allocation region, while other threads
160 // are also concurrently trying to allocate into it, we typically
161 // allocate a dummy object at the end of the region to ensure that
162 // no more allocations can take place in it. However, sometimes we
163 // want to know where the end of the last "real" object we allocated
164 // into the region was and this is what this keeps track.
165 HeapWord* _pre_dummy_top;
166
167 public:
168 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be
169 // assumed to contain zeros.
170 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
171 MemRegion mr, bool is_zeroed = false);
172
173 void set_bottom(HeapWord* value);
174 void set_end(HeapWord* value);
175
176 virtual HeapWord* saved_mark_word() const;
177 virtual void set_saved_mark();
178 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
179 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
180
181 // See the comment above in the declaration of _pre_dummy_top for an
182 // explanation of what it is.
183 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
184 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
185 _pre_dummy_top = pre_dummy_top;
186 }
187 HeapWord* pre_dummy_top() {
188 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
189 }
190 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
191
192 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
193 virtual void clear(bool mangle_space);
194
195 HeapWord* block_start(const void* p);
196 HeapWord* block_start_const(const void* p) const;
197
198 // Add offset table update.
199 virtual HeapWord* allocate(size_t word_size);
200 HeapWord* par_allocate(size_t word_size);
201
202 // MarkSweep support phase3
203 virtual HeapWord* initialize_threshold();
204 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
205
206 virtual void print() const;
207
208 void reset_bot() {
209 _offsets.zero_bottom_entry();
210 _offsets.initialize_threshold();
211 }
212
213 void update_bot_for_object(HeapWord* start, size_t word_size) {
214 _offsets.alloc_block(start, word_size);
215 }
216
217 void print_bot_on(outputStream* out) {
218 _offsets.print_on(out);
219 }
220 };
221
222 class HeapRegion: public G1OffsetTableContigSpace {
223 friend class VMStructs;
224 private:
225
226 enum HumongousType {
227 NotHumongous = 0,
228 StartsHumongous,
229 ContinuesHumongous
230 };
231
232 // Requires that the region "mr" be dense with objects, and begin and end
233 // with an object.
234 void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl);
235
236 // The remembered set for this region.
237 // (Might want to make this "inline" later, to avoid some alloc failure
238 // issues.)
239 HeapRegionRemSet* _rem_set;
240
241 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
242
243 protected:
244 // The index of this region in the heap region sequence.
245 uint _hrs_index;
246
247 HumongousType _humongous_type;
248 // For a humongous region, region in which it starts.
249 HeapRegion* _humongous_start_region;
250 // For the start region of a humongous sequence, it's original end().
251 HeapWord* _orig_end;
252
253 // True iff the region is in current collection_set.
254 bool _in_collection_set;
255
256 // True iff an attempt to evacuate an object in the region failed.
257 bool _evacuation_failed;
258
259 // A heap region may be a member one of a number of special subsets, each
260 // represented as linked lists through the field below. Currently, these
261 // sets include:
262 // The collection set.
263 // The set of allocation regions used in a collection pause.
264 // Spaces that may contain gray objects.
265 HeapRegion* _next_in_special_set;
266
267 // next region in the young "generation" region set
268 HeapRegion* _next_young_region;
269
270 // Next region whose cards need cleaning
271 HeapRegion* _next_dirty_cards_region;
272
273 // Fields used by the HeapRegionSetBase class and subclasses.
274 HeapRegion* _next;
275 #ifdef ASSERT
276 HeapRegionSetBase* _containing_set;
277 #endif // ASSERT
278 bool _pending_removal;
279
280 // For parallel heapRegion traversal.
281 jint _claimed;
282
283 // We use concurrent marking to determine the amount of live data
284 // in each heap region.
285 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
286 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
287
288 // The calculated GC efficiency of the region.
289 double _gc_efficiency;
290
291 enum YoungType {
292 NotYoung, // a region is not young
293 Young, // a region is young
294 Survivor // a region is young and it contains survivors
295 };
296
297 volatile YoungType _young_type;
298 int _young_index_in_cset;
299 SurvRateGroup* _surv_rate_group;
300 int _age_index;
301
302 // The start of the unmarked area. The unmarked area extends from this
303 // word until the top and/or end of the region, and is the part
304 // of the region for which no marking was done, i.e. objects may
305 // have been allocated in this part since the last mark phase.
306 // "prev" is the top at the start of the last completed marking.
307 // "next" is the top at the start of the in-progress marking (if any.)
308 HeapWord* _prev_top_at_mark_start;
309 HeapWord* _next_top_at_mark_start;
310 // If a collection pause is in progress, this is the top at the start
311 // of that pause.
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 }
321
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 }
327
328 // Cached attributes used in the collection set policy information
329
330 // The RSet length that was added to the total value
331 // for the collection set.
332 size_t _recorded_rs_length;
333
334 // The predicted elapsed time that was added to total value
335 // for the collection set.
336 double _predicted_elapsed_time_ms;
337
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;
341
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);
347
348 static int LogOfHRGrainBytes;
349 static int LogOfHRGrainWords;
350
351 static size_t GrainBytes;
352 static size_t GrainWords;
353 static size_t CardsPerRegion;
354
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 }
359
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);
367
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 };
379
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 }
388
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; }
392
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 }
398
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 }
406
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 }
415
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 }
425
426 // An upper bound on the number of live bytes in the region.
427 size_t max_live_bytes() { return used() - garbage_bytes(); }
428
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 }
433
434 void zero_marked_bytes() {
435 _prev_marked_bytes = _next_marked_bytes = 0;
436 }
437
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 }
445
446 // Return the number of distinct regions that are covered by this region:
447 // 1 if the region is not humongous, >= 1 if the region is humongous.
448 uint region_num() const {
449 if (!isHumongous()) {
450 return 1U;
451 } else {
452 assert(startsHumongous(), "doesn't make sense on HC regions");
453 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
454 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
455 }
456 }
457
458 // Return the index + 1 of the last HC regions that's associated
459 // with this HS region.
460 uint last_hc_index() const {
461 assert(startsHumongous(), "don't call this otherwise");
462 return hrs_index() + region_num();
463 }
464
465 // Same as Space::is_in_reserved, but will use the original size of the region.
466 // The original size is different only for start humongous regions. They get
467 // their _end set up to be the end of the last continues region of the
468 // corresponding humongous object.
469 bool is_in_reserved_raw(const void* p) const {
470 return _bottom <= p && p < _orig_end;
471 }
472
473 // Makes the current region be a "starts humongous" region, i.e.,
474 // the first region in a series of one or more contiguous regions
475 // that will contain a single "humongous" object. The two parameters
476 // are as follows:
477 //
478 // new_top : The new value of the top field of this region which
479 // points to the end of the humongous object that's being
480 // allocated. If there is more than one region in the series, top
481 // will lie beyond this region's original end field and on the last
482 // region in the series.
483 //
484 // new_end : The new value of the end field of this region which
485 // points to the end of the last region in the series. If there is
486 // one region in the series (namely: this one) end will be the same
487 // as the original end of this region.
488 //
489 // Updating top and end as described above makes this region look as
490 // if it spans the entire space taken up by all the regions in the
491 // series and an single allocation moved its top to new_top. This
492 // ensures that the space (capacity / allocated) taken up by all
493 // humongous regions can be calculated by just looking at the
494 // "starts humongous" regions and by ignoring the "continues
495 // humongous" regions.
496 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
497
498 // Makes the current region be a "continues humongous'
499 // region. first_hr is the "start humongous" region of the series
500 // which this region will be part of.
501 void set_continuesHumongous(HeapRegion* first_hr);
502
503 // Unsets the humongous-related fields on the region.
504 void set_notHumongous();
505
506 // If the region has a remembered set, return a pointer to it.
507 HeapRegionRemSet* rem_set() const {
508 return _rem_set;
509 }
510
511 // True iff the region is in current collection_set.
512 bool in_collection_set() const {
513 return _in_collection_set;
514 }
515 void set_in_collection_set(bool b) {
516 _in_collection_set = b;
517 }
518 HeapRegion* next_in_collection_set() {
519 assert(in_collection_set(), "should only invoke on member of CS.");
520 assert(_next_in_special_set == NULL ||
521 _next_in_special_set->in_collection_set(),
522 "Malformed CS.");
523 return _next_in_special_set;
524 }
525 void set_next_in_collection_set(HeapRegion* r) {
526 assert(in_collection_set(), "should only invoke on member of CS.");
527 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
528 _next_in_special_set = r;
529 }
530
531 // Methods used by the HeapRegionSetBase class and subclasses.
532
533 // Getter and setter for the next field used to link regions into
534 // linked lists.
535 HeapRegion* next() { return _next; }
536
537 void set_next(HeapRegion* next) { _next = next; }
538
539 // Every region added to a set is tagged with a reference to that
540 // set. This is used for doing consistency checking to make sure that
541 // the contents of a set are as they should be and it's only
542 // available in non-product builds.
543 #ifdef ASSERT
544 void set_containing_set(HeapRegionSetBase* containing_set) {
545 assert((containing_set == NULL && _containing_set != NULL) ||
546 (containing_set != NULL && _containing_set == NULL),
547 err_msg("containing_set: "PTR_FORMAT" "
548 "_containing_set: "PTR_FORMAT,
549 containing_set, _containing_set));
550
551 _containing_set = containing_set;
552 }
553
554 HeapRegionSetBase* containing_set() { return _containing_set; }
555 #else // ASSERT
556 void set_containing_set(HeapRegionSetBase* containing_set) { }
557
558 // containing_set() is only used in asserts so there's no reason
559 // to provide a dummy version of it.
560 #endif // ASSERT
561
562 // If we want to remove regions from a list in bulk we can simply tag
563 // them with the pending_removal tag and call the
564 // remove_all_pending() method on the list.
565
566 bool pending_removal() { return _pending_removal; }
567
568 void set_pending_removal(bool pending_removal) {
569 if (pending_removal) {
570 assert(!_pending_removal && containing_set() != NULL,
571 "can only set pending removal to true if it's false and "
572 "the region belongs to a region set");
573 } else {
574 assert( _pending_removal && containing_set() == NULL,
575 "can only set pending removal to false if it's true and "
576 "the region does not belong to a region set");
577 }
578
579 _pending_removal = pending_removal;
580 }
581
582 HeapRegion* get_next_young_region() { return _next_young_region; }
583 void set_next_young_region(HeapRegion* hr) {
584 _next_young_region = hr;
585 }
586
587 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
588 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
589 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
590 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
591
592 HeapWord* orig_end() { return _orig_end; }
593
594 // Allows logical separation between objects allocated before and after.
595 void save_marks();
596
597 // Reset HR stuff to default values.
598 void hr_clear(bool par, bool clear_space);
599 void par_clear();
600
601 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
602
603 // Get the start of the unmarked area in this region.
604 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
605 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
606
607 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
608 // allocated in the current region before the last call to "save_mark".
609 void oop_before_save_marks_iterate(ExtendedOopClosure* cl);
610
611 // Note the start or end of marking. This tells the heap region
612 // that the collector is about to start or has finished (concurrently)
613 // marking the heap.
614
615 // Notify the region that concurrent marking is starting. Initialize
616 // all fields related to the next marking info.
617 inline void note_start_of_marking();
618
619 // Notify the region that concurrent marking has finished. Copy the
620 // (now finalized) next marking info fields into the prev marking
621 // info fields.
622 inline void note_end_of_marking();
623
624 // Notify the region that it will be used as to-space during a GC
625 // and we are about to start copying objects into it.
626 inline void note_start_of_copying(bool during_initial_mark);
627
628 // Notify the region that it ceases being to-space during a GC and
629 // we will not copy objects into it any more.
630 inline void note_end_of_copying(bool during_initial_mark);
631
632 // Notify the region that we are about to start processing
633 // self-forwarded objects during evac failure handling.
634 void note_self_forwarding_removal_start(bool during_initial_mark,
635 bool during_conc_mark);
636
637 // Notify the region that we have finished processing self-forwarded
638 // objects during evac failure handling.
639 void note_self_forwarding_removal_end(bool during_initial_mark,
640 bool during_conc_mark,
641 size_t marked_bytes);
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 void reset_during_compaction() {
648 assert(isHumongous() && startsHumongous(),
649 "should only be called for starts humongous regions");
650
651 zero_marked_bytes();
652 init_top_at_mark_start();
653 }
654
655 void calc_gc_efficiency(void);
656 double gc_efficiency() { return _gc_efficiency;}
657
658 bool is_young() const { return _young_type != NotYoung; }
659 bool is_survivor() const { return _young_type == Survivor; }
660
661 int young_index_in_cset() const { return _young_index_in_cset; }
662 void set_young_index_in_cset(int index) {
663 assert( (index == -1) || is_young(), "pre-condition" );
664 _young_index_in_cset = index;
665 }
666
667 int age_in_surv_rate_group() {
668 assert( _surv_rate_group != NULL, "pre-condition" );
669 assert( _age_index > -1, "pre-condition" );
670 return _surv_rate_group->age_in_group(_age_index);
671 }
672
673 void record_surv_words_in_group(size_t words_survived) {
674 assert( _surv_rate_group != NULL, "pre-condition" );
675 assert( _age_index > -1, "pre-condition" );
676 int age_in_group = age_in_surv_rate_group();
677 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
678 }
679
680 int age_in_surv_rate_group_cond() {
681 if (_surv_rate_group != NULL)
682 return age_in_surv_rate_group();
683 else
684 return -1;
685 }
686
687 SurvRateGroup* surv_rate_group() {
688 return _surv_rate_group;
689 }
690
691 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
692 assert( surv_rate_group != NULL, "pre-condition" );
693 assert( _surv_rate_group == NULL, "pre-condition" );
694 assert( is_young(), "pre-condition" );
695
696 _surv_rate_group = surv_rate_group;
697 _age_index = surv_rate_group->next_age_index();
698 }
699
700 void uninstall_surv_rate_group() {
701 if (_surv_rate_group != NULL) {
702 assert( _age_index > -1, "pre-condition" );
703 assert( is_young(), "pre-condition" );
704
705 _surv_rate_group = NULL;
706 _age_index = -1;
707 } else {
708 assert( _age_index == -1, "pre-condition" );
709 }
710 }
711
712 void set_young() { set_young_type(Young); }
713
714 void set_survivor() { set_young_type(Survivor); }
715
716 void set_not_young() { set_young_type(NotYoung); }
717
718 // Determine if an object has been allocated since the last
719 // mark performed by the collector. This returns true iff the object
720 // is within the unmarked area of the region.
721 bool obj_allocated_since_prev_marking(oop obj) const {
722 return (HeapWord *) obj >= prev_top_at_mark_start();
723 }
724 bool obj_allocated_since_next_marking(oop obj) const {
725 return (HeapWord *) obj >= next_top_at_mark_start();
726 }
727
728 // For parallel heapRegion traversal.
729 bool claimHeapRegion(int claimValue);
730 jint claim_value() { return _claimed; }
731 // Use this carefully: only when you're sure no one is claiming...
732 void set_claim_value(int claimValue) { _claimed = claimValue; }
733
734 // Returns the "evacuation_failed" property of the region.
735 bool evacuation_failed() { return _evacuation_failed; }
736
737 // Sets the "evacuation_failed" property of the region.
738 void set_evacuation_failed(bool b) {
739 _evacuation_failed = b;
740
741 if (b) {
742 _next_marked_bytes = 0;
743 }
744 }
745
746 // Requires that "mr" be entirely within the region.
747 // Apply "cl->do_object" to all objects that intersect with "mr".
748 // If the iteration encounters an unparseable portion of the region,
749 // or if "cl->abort()" is true after a closure application,
750 // terminate the iteration and return the address of the start of the
751 // subregion that isn't done. (The two can be distinguished by querying
752 // "cl->abort()".) Return of "NULL" indicates that the iteration
753 // completed.
754 HeapWord*
755 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
756
757 // filter_young: if true and the region is a young region then we
758 // skip the iteration.
759 // card_ptr: if not NULL, and we decide that the card is not young
760 // and we iterate over it, we'll clean the card before we start the
761 // iteration.
762 HeapWord*
763 oops_on_card_seq_iterate_careful(MemRegion mr,
764 FilterOutOfRegionClosure* cl,
765 bool filter_young,
766 jbyte* card_ptr);
767
768 // A version of block start that is guaranteed to find *some* block
769 // boundary at or before "p", but does not object iteration, and may
770 // therefore be used safely when the heap is unparseable.
771 HeapWord* block_start_careful(const void* p) const {
772 return _offsets.block_start_careful(p);
773 }
774
775 // Requires that "addr" is within the region. Returns the start of the
776 // first ("careful") block that starts at or after "addr", or else the
777 // "end" of the region if there is no such block.
778 HeapWord* next_block_start_careful(HeapWord* addr);
779
780 size_t recorded_rs_length() const { return _recorded_rs_length; }
781 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
782 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
783
784 void set_recorded_rs_length(size_t rs_length) {
785 _recorded_rs_length = rs_length;
786 }
787
788 void set_predicted_elapsed_time_ms(double ms) {
789 _predicted_elapsed_time_ms = ms;
790 }
791
792 void set_predicted_bytes_to_copy(size_t bytes) {
793 _predicted_bytes_to_copy = bytes;
794 }
795
796 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
797 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
798 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
799
800 virtual CompactibleSpace* next_compaction_space() const;
801
802 virtual void reset_after_compaction();
803
804 void print() const;
805 void print_on(outputStream* st) const;
806
807 // vo == UsePrevMarking -> use "prev" marking information,
808 // vo == UseNextMarking -> use "next" marking information
809 // vo == UseMarkWord -> use the mark word in the object header
810 //
811 // NOTE: Only the "prev" marking information is guaranteed to be
812 // consistent most of the time, so most calls to this should use
813 // vo == UsePrevMarking.
814 // Currently, there is only one case where this is called with
815 // vo == UseNextMarking, which is to verify the "next" marking
816 // information at the end of remark.
817 // Currently there is only one place where this is called with
818 // vo == UseMarkWord, which is to verify the marking during a
819 // full GC.
820 void verify(VerifyOption vo, bool *failures) const;
821
822 // Override; it uses the "prev" marking information
823 virtual void verify() const;
824 };
825
826 // HeapRegionClosure is used for iterating over regions.
827 // Terminates the iteration when the "doHeapRegion" method returns "true".
828 class HeapRegionClosure : public StackObj {
829 friend class HeapRegionSeq;
830 friend class G1CollectedHeap;
831
832 bool _complete;
833 void incomplete() { _complete = false; }
834
835 public:
836 HeapRegionClosure(): _complete(true) {}
837
838 // Typically called on each region until it returns true.
839 virtual bool doHeapRegion(HeapRegion* r) = 0;
840
841 // True after iteration if the closure was applied to all heap regions
842 // and returned "false" in all cases.
843 bool complete() { return _complete; }
844 };
845
846 #endif // SERIALGC
847
848 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP