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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7 * published by the Free Software Foundation.
8 *
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
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 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
169 MemRegion mr);
170
171 void set_bottom(HeapWord* value);
172 void set_end(HeapWord* value);
173
174 virtual HeapWord* saved_mark_word() const;
175 virtual void set_saved_mark();
176 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
177 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
178
179 // See the comment above in the declaration of _pre_dummy_top for an
180 // explanation of what it is.
181 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
182 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
183 _pre_dummy_top = pre_dummy_top;
184 }
185 HeapWord* pre_dummy_top() {
186 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
187 }
188 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
189
190 virtual void clear(bool mangle_space);
191
192 HeapWord* block_start(const void* p);
193 HeapWord* block_start_const(const void* p) const;
194
195 // Add offset table update.
196 virtual HeapWord* allocate(size_t word_size);
197 HeapWord* par_allocate(size_t word_size);
198
199 // MarkSweep support phase3
200 virtual HeapWord* initialize_threshold();
201 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
202
203 virtual void print() const;
204
205 void reset_bot() {
206 _offsets.zero_bottom_entry();
207 _offsets.initialize_threshold();
208 }
209
210 void update_bot_for_object(HeapWord* start, size_t word_size) {
211 _offsets.alloc_block(start, word_size);
212 }
213
214 void print_bot_on(outputStream* out) {
215 _offsets.print_on(out);
216 }
217 };
218
219 class HeapRegion: public G1OffsetTableContigSpace {
220 friend class VMStructs;
221 private:
222
223 enum HumongousType {
224 NotHumongous = 0,
225 StartsHumongous,
226 ContinuesHumongous
227 };
228
229 // Requires that the region "mr" be dense with objects, and begin and end
230 // with an object.
231 void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl);
232
233 // The remembered set for this region.
234 // (Might want to make this "inline" later, to avoid some alloc failure
235 // issues.)
236 HeapRegionRemSet* _rem_set;
237
238 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
239
240 protected:
241 // The index of this region in the heap region sequence.
242 uint _hrs_index;
243
244 HumongousType _humongous_type;
245 // For a humongous region, region in which it starts.
246 HeapRegion* _humongous_start_region;
247 // For the start region of a humongous sequence, it's original end().
248 HeapWord* _orig_end;
249
250 // True iff the region is in current collection_set.
251 bool _in_collection_set;
252
253 // True iff an attempt to evacuate an object in the region failed.
254 bool _evacuation_failed;
255
256 // A heap region may be a member one of a number of special subsets, each
257 // represented as linked lists through the field below. Currently, these
258 // sets include:
259 // The collection set.
260 // The set of allocation regions used in a collection pause.
261 // Spaces that may contain gray objects.
262 HeapRegion* _next_in_special_set;
263
264 // next region in the young "generation" region set
265 HeapRegion* _next_young_region;
266
267 // Next region whose cards need cleaning
268 HeapRegion* _next_dirty_cards_region;
269
270 // Fields used by the HeapRegionSetBase class and subclasses.
271 HeapRegion* _next;
272 #ifdef ASSERT
273 HeapRegionSetBase* _containing_set;
274 #endif // ASSERT
275 bool _pending_removal;
276
277 // For parallel heapRegion traversal.
278 jint _claimed;
279
280 // We use concurrent marking to determine the amount of live data
281 // in each heap region.
282 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
283 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
284
285 // The calculated GC efficiency of the region.
286 double _gc_efficiency;
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 void init_top_at_mark_start() {
311 assert(_prev_marked_bytes == 0 &&
312 _next_marked_bytes == 0,
313 "Must be called after zero_marked_bytes.");
314 HeapWord* bot = bottom();
315 _prev_top_at_mark_start = bot;
316 _next_top_at_mark_start = bot;
317 }
318
319 void set_young_type(YoungType new_type) {
320 //assert(_young_type != new_type, "setting the same type" );
321 // TODO: add more assertions here
322 _young_type = new_type;
323 }
324
325 // Cached attributes used in the collection set policy information
326
327 // The RSet length that was added to the total value
328 // for the collection set.
329 size_t _recorded_rs_length;
330
331 // The predicted elapsed time that was added to total value
332 // for the collection set.
333 double _predicted_elapsed_time_ms;
334
335 // The predicted number of bytes to copy that was added to
336 // the total value for the collection set.
337 size_t _predicted_bytes_to_copy;
338
339 public:
340 HeapRegion(uint hrs_index,
341 G1BlockOffsetSharedArray* sharedOffsetArray,
342 MemRegion mr);
343
344 static int LogOfHRGrainBytes;
345 static int LogOfHRGrainWords;
346
347 static size_t GrainBytes;
348 static size_t GrainWords;
349 static size_t CardsPerRegion;
350
351 static size_t align_up_to_region_byte_size(size_t sz) {
352 return (sz + (size_t) GrainBytes - 1) &
353 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
354 }
355
356 // It sets up the heap region size (GrainBytes / GrainWords), as
357 // well as other related fields that are based on the heap region
358 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
359 // CardsPerRegion). All those fields are considered constant
360 // throughout the JVM's execution, therefore they should only be set
361 // up once during initialization time.
362 static void setup_heap_region_size(uintx min_heap_size);
363
364 enum ClaimValues {
365 InitialClaimValue = 0,
366 FinalCountClaimValue = 1,
367 NoteEndClaimValue = 2,
368 ScrubRemSetClaimValue = 3,
369 ParVerifyClaimValue = 4,
370 RebuildRSClaimValue = 5,
371 ParEvacFailureClaimValue = 6,
372 AggregateCountClaimValue = 7,
373 VerifyCountClaimValue = 8
374 };
375
376 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
377 assert(is_young(), "we can only skip BOT updates on young regions");
378 return ContiguousSpace::par_allocate(word_size);
379 }
380 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
381 assert(is_young(), "we can only skip BOT updates on young regions");
382 return ContiguousSpace::allocate(word_size);
383 }
384
385 // If this region is a member of a HeapRegionSeq, the index in that
386 // sequence, otherwise -1.
387 uint hrs_index() const { return _hrs_index; }
388
389 // The number of bytes marked live in the region in the last marking phase.
390 size_t marked_bytes() { return _prev_marked_bytes; }
391 size_t live_bytes() {
392 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
393 }
394
395 // The number of bytes counted in the next marking.
396 size_t next_marked_bytes() { return _next_marked_bytes; }
397 // The number of bytes live wrt the next marking.
398 size_t next_live_bytes() {
399 return
400 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
401 }
402
403 // A lower bound on the amount of garbage bytes in the region.
404 size_t garbage_bytes() {
405 size_t used_at_mark_start_bytes =
406 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
407 assert(used_at_mark_start_bytes >= marked_bytes(),
408 "Can't mark more than we have.");
409 return used_at_mark_start_bytes - marked_bytes();
410 }
411
412 // Return the amount of bytes we'll reclaim if we collect this
413 // region. This includes not only the known garbage bytes in the
414 // region but also any unallocated space in it, i.e., [top, end),
415 // since it will also be reclaimed if we collect the region.
416 size_t reclaimable_bytes() {
417 size_t known_live_bytes = live_bytes();
418 assert(known_live_bytes <= capacity(), "sanity");
419 return capacity() - known_live_bytes;
420 }
421
422 // An upper bound on the number of live bytes in the region.
423 size_t max_live_bytes() { return used() - garbage_bytes(); }
424
425 void add_to_marked_bytes(size_t incr_bytes) {
426 _next_marked_bytes = _next_marked_bytes + incr_bytes;
427 assert(_next_marked_bytes <= used(), "invariant" );
428 }
429
430 void zero_marked_bytes() {
431 _prev_marked_bytes = _next_marked_bytes = 0;
432 }
433
434 bool isHumongous() const { return _humongous_type != NotHumongous; }
435 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
436 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
437 // For a humongous region, region in which it starts.
438 HeapRegion* humongous_start_region() const {
439 return _humongous_start_region;
440 }
441
442 // Return the number of distinct regions that are covered by this region:
443 // 1 if the region is not humongous, >= 1 if the region is humongous.
444 uint region_num() const {
445 if (!isHumongous()) {
446 return 1U;
447 } else {
448 assert(startsHumongous(), "doesn't make sense on HC regions");
449 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
450 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
451 }
452 }
453
454 // Return the index + 1 of the last HC regions that's associated
455 // with this HS region.
456 uint last_hc_index() const {
457 assert(startsHumongous(), "don't call this otherwise");
458 return hrs_index() + region_num();
459 }
460
461 // Same as Space::is_in_reserved, but will use the original size of the region.
462 // The original size is different only for start humongous regions. They get
463 // their _end set up to be the end of the last continues region of the
464 // corresponding humongous object.
465 bool is_in_reserved_raw(const void* p) const {
466 return _bottom <= p && p < _orig_end;
467 }
468
469 // Makes the current region be a "starts humongous" region, i.e.,
470 // the first region in a series of one or more contiguous regions
471 // that will contain a single "humongous" object. The two parameters
472 // are as follows:
473 //
474 // new_top : The new value of the top field of this region which
475 // points to the end of the humongous object that's being
476 // allocated. If there is more than one region in the series, top
477 // will lie beyond this region's original end field and on the last
478 // region in the series.
479 //
480 // new_end : The new value of the end field of this region which
481 // points to the end of the last region in the series. If there is
482 // one region in the series (namely: this one) end will be the same
483 // as the original end of this region.
484 //
485 // Updating top and end as described above makes this region look as
486 // if it spans the entire space taken up by all the regions in the
487 // series and an single allocation moved its top to new_top. This
488 // ensures that the space (capacity / allocated) taken up by all
489 // humongous regions can be calculated by just looking at the
490 // "starts humongous" regions and by ignoring the "continues
491 // humongous" regions.
492 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
493
494 // Makes the current region be a "continues humongous'
495 // region. first_hr is the "start humongous" region of the series
496 // which this region will be part of.
497 void set_continuesHumongous(HeapRegion* first_hr);
498
499 // Unsets the humongous-related fields on the region.
500 void set_notHumongous();
501
502 // If the region has a remembered set, return a pointer to it.
503 HeapRegionRemSet* rem_set() const {
504 return _rem_set;
505 }
506
507 // True iff the region is in current collection_set.
508 bool in_collection_set() const {
509 return _in_collection_set;
510 }
511 void set_in_collection_set(bool b) {
512 _in_collection_set = b;
513 }
514 HeapRegion* next_in_collection_set() {
515 assert(in_collection_set(), "should only invoke on member of CS.");
516 assert(_next_in_special_set == NULL ||
517 _next_in_special_set->in_collection_set(),
518 "Malformed CS.");
519 return _next_in_special_set;
520 }
521 void set_next_in_collection_set(HeapRegion* r) {
522 assert(in_collection_set(), "should only invoke on member of CS.");
523 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
524 _next_in_special_set = r;
525 }
526
527 // Methods used by the HeapRegionSetBase class and subclasses.
528
529 // Getter and setter for the next field used to link regions into
530 // linked lists.
531 HeapRegion* next() { return _next; }
532
533 void set_next(HeapRegion* next) { _next = next; }
534
535 // Every region added to a set is tagged with a reference to that
536 // set. This is used for doing consistency checking to make sure that
537 // the contents of a set are as they should be and it's only
538 // available in non-product builds.
539 #ifdef ASSERT
540 void set_containing_set(HeapRegionSetBase* containing_set) {
541 assert((containing_set == NULL && _containing_set != NULL) ||
542 (containing_set != NULL && _containing_set == NULL),
543 err_msg("containing_set: "PTR_FORMAT" "
544 "_containing_set: "PTR_FORMAT,
545 containing_set, _containing_set));
546
547 _containing_set = containing_set;
548 }
549
550 HeapRegionSetBase* containing_set() { return _containing_set; }
551 #else // ASSERT
552 void set_containing_set(HeapRegionSetBase* containing_set) { }
553
554 // containing_set() is only used in asserts so there's no reason
555 // to provide a dummy version of it.
556 #endif // ASSERT
557
558 // If we want to remove regions from a list in bulk we can simply tag
559 // them with the pending_removal tag and call the
560 // remove_all_pending() method on the list.
561
562 bool pending_removal() { return _pending_removal; }
563
564 void set_pending_removal(bool pending_removal) {
565 if (pending_removal) {
566 assert(!_pending_removal && containing_set() != NULL,
567 "can only set pending removal to true if it's false and "
568 "the region belongs to a region set");
569 } else {
570 assert( _pending_removal && containing_set() == NULL,
571 "can only set pending removal to false if it's true and "
572 "the region does not belong to a region set");
573 }
574
575 _pending_removal = pending_removal;
576 }
577
578 HeapRegion* get_next_young_region() { return _next_young_region; }
579 void set_next_young_region(HeapRegion* hr) {
580 _next_young_region = hr;
581 }
582
583 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
584 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
585 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
586 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
587
588 HeapWord* orig_end() { return _orig_end; }
589
590 // Allows logical separation between objects allocated before and after.
591 void save_marks();
592
593 // Reset HR stuff to default values.
594 void hr_clear(bool par, bool clear_space);
595 void par_clear();
596
597 // Get the start of the unmarked area in this region.
598 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
599 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
600
601 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
602 // allocated in the current region before the last call to "save_mark".
603 void oop_before_save_marks_iterate(ExtendedOopClosure* cl);
604
605 // Note the start or end of marking. This tells the heap region
606 // that the collector is about to start or has finished (concurrently)
607 // marking the heap.
608
609 // Notify the region that concurrent marking is starting. Initialize
610 // all fields related to the next marking info.
611 inline void note_start_of_marking();
612
613 // Notify the region that concurrent marking has finished. Copy the
614 // (now finalized) next marking info fields into the prev marking
615 // info fields.
616 inline void note_end_of_marking();
617
618 // Notify the region that it will be used as to-space during a GC
619 // and we are about to start copying objects into it.
620 inline void note_start_of_copying(bool during_initial_mark);
621
622 // Notify the region that it ceases being to-space during a GC and
623 // we will not copy objects into it any more.
624 inline void note_end_of_copying(bool during_initial_mark);
625
626 // Notify the region that we are about to start processing
627 // self-forwarded objects during evac failure handling.
628 void note_self_forwarding_removal_start(bool during_initial_mark,
629 bool during_conc_mark);
630
631 // Notify the region that we have finished processing self-forwarded
632 // objects during evac failure handling.
633 void note_self_forwarding_removal_end(bool during_initial_mark,
634 bool during_conc_mark,
635 size_t marked_bytes);
636
637 // Returns "false" iff no object in the region was allocated when the
638 // last mark phase ended.
639 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
640
641 void reset_during_compaction() {
642 assert(isHumongous() && startsHumongous(),
643 "should only be called for starts humongous regions");
644
645 zero_marked_bytes();
646 init_top_at_mark_start();
647 }
648
649 void calc_gc_efficiency(void);
650 double gc_efficiency() { return _gc_efficiency;}
651
652 bool is_young() const { return _young_type != NotYoung; }
653 bool is_survivor() const { return _young_type == Survivor; }
654
655 int young_index_in_cset() const { return _young_index_in_cset; }
656 void set_young_index_in_cset(int index) {
657 assert( (index == -1) || is_young(), "pre-condition" );
658 _young_index_in_cset = index;
659 }
660
661 int age_in_surv_rate_group() {
662 assert( _surv_rate_group != NULL, "pre-condition" );
663 assert( _age_index > -1, "pre-condition" );
664 return _surv_rate_group->age_in_group(_age_index);
665 }
666
667 void record_surv_words_in_group(size_t words_survived) {
668 assert( _surv_rate_group != NULL, "pre-condition" );
669 assert( _age_index > -1, "pre-condition" );
670 int age_in_group = age_in_surv_rate_group();
671 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
672 }
673
674 int age_in_surv_rate_group_cond() {
675 if (_surv_rate_group != NULL)
676 return age_in_surv_rate_group();
677 else
678 return -1;
679 }
680
681 SurvRateGroup* surv_rate_group() {
682 return _surv_rate_group;
683 }
684
685 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
686 assert( surv_rate_group != NULL, "pre-condition" );
687 assert( _surv_rate_group == NULL, "pre-condition" );
688 assert( is_young(), "pre-condition" );
689
690 _surv_rate_group = surv_rate_group;
691 _age_index = surv_rate_group->next_age_index();
692 }
693
694 void uninstall_surv_rate_group() {
695 if (_surv_rate_group != NULL) {
696 assert( _age_index > -1, "pre-condition" );
697 assert( is_young(), "pre-condition" );
698
699 _surv_rate_group = NULL;
700 _age_index = -1;
701 } else {
702 assert( _age_index == -1, "pre-condition" );
703 }
704 }
705
706 void set_young() { set_young_type(Young); }
707
708 void set_survivor() { set_young_type(Survivor); }
709
710 void set_not_young() { set_young_type(NotYoung); }
711
712 // Determine if an object has been allocated since the last
713 // mark performed by the collector. This returns true iff the object
714 // is within the unmarked area of the region.
715 bool obj_allocated_since_prev_marking(oop obj) const {
716 return (HeapWord *) obj >= prev_top_at_mark_start();
717 }
718 bool obj_allocated_since_next_marking(oop obj) const {
719 return (HeapWord *) obj >= next_top_at_mark_start();
720 }
721
722 // For parallel heapRegion traversal.
723 bool claimHeapRegion(int claimValue);
724 jint claim_value() { return _claimed; }
725 // Use this carefully: only when you're sure no one is claiming...
726 void set_claim_value(int claimValue) { _claimed = claimValue; }
727
728 // Returns the "evacuation_failed" property of the region.
729 bool evacuation_failed() { return _evacuation_failed; }
730
731 // Sets the "evacuation_failed" property of the region.
732 void set_evacuation_failed(bool b) {
733 _evacuation_failed = b;
734
735 if (b) {
736 _next_marked_bytes = 0;
737 }
738 }
739
740 // Requires that "mr" be entirely within the region.
741 // Apply "cl->do_object" to all objects that intersect with "mr".
742 // If the iteration encounters an unparseable portion of the region,
743 // or if "cl->abort()" is true after a closure application,
744 // terminate the iteration and return the address of the start of the
745 // subregion that isn't done. (The two can be distinguished by querying
746 // "cl->abort()".) Return of "NULL" indicates that the iteration
747 // completed.
748 HeapWord*
749 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
750
751 // filter_young: if true and the region is a young region then we
752 // skip the iteration.
753 // card_ptr: if not NULL, and we decide that the card is not young
754 // and we iterate over it, we'll clean the card before we start the
755 // iteration.
756 HeapWord*
757 oops_on_card_seq_iterate_careful(MemRegion mr,
758 FilterOutOfRegionClosure* cl,
759 bool filter_young,
760 jbyte* card_ptr);
761
762 // A version of block start that is guaranteed to find *some* block
763 // boundary at or before "p", but does not object iteration, and may
764 // therefore be used safely when the heap is unparseable.
765 HeapWord* block_start_careful(const void* p) const {
766 return _offsets.block_start_careful(p);
767 }
768
769 // Requires that "addr" is within the region. Returns the start of the
770 // first ("careful") block that starts at or after "addr", or else the
771 // "end" of the region if there is no such block.
772 HeapWord* next_block_start_careful(HeapWord* addr);
773
774 size_t recorded_rs_length() const { return _recorded_rs_length; }
775 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
776 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
777
778 void set_recorded_rs_length(size_t rs_length) {
779 _recorded_rs_length = rs_length;
780 }
781
782 void set_predicted_elapsed_time_ms(double ms) {
783 _predicted_elapsed_time_ms = ms;
784 }
785
786 void set_predicted_bytes_to_copy(size_t bytes) {
787 _predicted_bytes_to_copy = bytes;
788 }
789
790 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
791 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
792 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
793
794 virtual CompactibleSpace* next_compaction_space() const;
795
796 virtual void reset_after_compaction();
797
798 void print() const;
799 void print_on(outputStream* st) const;
800
801 // vo == UsePrevMarking -> use "prev" marking information,
802 // vo == UseNextMarking -> use "next" marking information
803 // vo == UseMarkWord -> use the mark word in the object header
804 //
805 // NOTE: Only the "prev" marking information is guaranteed to be
806 // consistent most of the time, so most calls to this should use
807 // vo == UsePrevMarking.
808 // Currently, there is only one case where this is called with
809 // vo == UseNextMarking, which is to verify the "next" marking
810 // information at the end of remark.
811 // Currently there is only one place where this is called with
812 // vo == UseMarkWord, which is to verify the marking during a
813 // full GC.
814 void verify(VerifyOption vo, bool *failures) const;
815
816 // Override; it uses the "prev" marking information
817 virtual void verify() const;
818 };
819
820 // HeapRegionClosure is used for iterating over regions.
821 // Terminates the iteration when the "doHeapRegion" method returns "true".
822 class HeapRegionClosure : public StackObj {
823 friend class HeapRegionSeq;
824 friend class G1CollectedHeap;
825
826 bool _complete;
827 void incomplete() { _complete = false; }
828
829 public:
830 HeapRegionClosure(): _complete(true) {}
831
832 // Typically called on each region until it returns true.
833 virtual bool doHeapRegion(HeapRegion* r) = 0;
834
835 // True after iteration if the closure was applied to all heap regions
836 // and returned "false" in all cases.
837 bool complete() { return _complete; }
838 };
839
840 #endif // SERIALGC
841
842 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP