1 /*
2 * Copyright (c) 2001, 2014, 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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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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.hpp"
29 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
30 #include "gc_implementation/g1/heapRegionType.hpp"
31 #include "gc_implementation/g1/survRateGroup.hpp"
32 #include "gc_implementation/shared/ageTable.hpp"
33 #include "gc_implementation/shared/spaceDecorator.hpp"
34 #include "memory/space.inline.hpp"
35 #include "memory/watermark.hpp"
36 #include "utilities/macros.hpp"
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 HeapRegionRemSet;
49 class HeapRegionRemSetIterator;
50 class HeapRegion;
51 class HeapRegionSetBase;
52 class nmethod;
53
54 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
55 #define HR_FORMAT_PARAMS(_hr_) \
56 (_hr_)->hrm_index(), \
57 (_hr_)->get_short_type_str(), \
58 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
59
60 // sentinel value for hrm_index
61 #define G1_NO_HRM_INDEX ((uint) -1)
62
63 // A dirty card to oop closure for heap regions. It
64 // knows how to get the G1 heap and how to use the bitmap
65 // in the concurrent marker used by G1 to filter remembered
66 // sets.
67
68 class HeapRegionDCTOC : public DirtyCardToOopClosure {
69 public:
70 // Specification of possible DirtyCardToOopClosure filtering.
71 enum FilterKind {
72 NoFilterKind,
73 IntoCSFilterKind,
74 OutOfRegionFilterKind
75 };
76
77 protected:
78 HeapRegion* _hr;
79 FilterKind _fk;
80 G1CollectedHeap* _g1;
81
82 // Walk the given memory region from bottom to (actual) top
83 // looking for objects and applying the oop closure (_cl) to
84 // them. The base implementation of this treats the area as
85 // blocks, where a block may or may not be an object. Sub-
86 // classes should override this to provide more accurate
87 // or possibly more efficient walking.
88 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
89
90 public:
91 HeapRegionDCTOC(G1CollectedHeap* g1,
92 HeapRegion* hr, ExtendedOopClosure* cl,
93 CardTableModRefBS::PrecisionStyle precision,
94 FilterKind fk);
95 };
96
97 // The complicating factor is that BlockOffsetTable diverged
98 // significantly, and we need functionality that is only in the G1 version.
99 // So I copied that code, which led to an alternate G1 version of
100 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
101 // be reconciled, then G1OffsetTableContigSpace could go away.
102
103 // The idea behind time stamps is the following. Doing a save_marks on
104 // all regions at every GC pause is time consuming (if I remember
105 // well, 10ms or so). So, we would like to do that only for regions
106 // that are GC alloc regions. To achieve this, we use time
107 // stamps. For every evacuation pause, G1CollectedHeap generates a
108 // unique time stamp (essentially a counter that gets
109 // incremented). Every time we want to call save_marks on a region,
110 // we set the saved_mark_word to top and also copy the current GC
111 // time stamp to the time stamp field of the space. Reading the
112 // saved_mark_word involves checking the time stamp of the
113 // region. If it is the same as the current GC time stamp, then we
114 // can safely read the saved_mark_word field, as it is valid. If the
115 // time stamp of the region is not the same as the current GC time
116 // stamp, then we instead read top, as the saved_mark_word field is
117 // invalid. Time stamps (on the regions and also on the
118 // G1CollectedHeap) are reset at every cleanup (we iterate over
119 // the regions anyway) and at the end of a Full GC. The current scheme
120 // that uses sequential unsigned ints will fail only if we have 4b
121 // evacuation pauses between two cleanups, which is _highly_ unlikely.
122 class G1OffsetTableContigSpace: public CompactibleSpace {
123 friend class VMStructs;
124 HeapWord* _top;
125 protected:
126 G1BlockOffsetArrayContigSpace _offsets;
127 Mutex _par_alloc_lock;
128 volatile unsigned _gc_time_stamp;
129 // When we need to retire an allocation region, while other threads
130 // are also concurrently trying to allocate into it, we typically
131 // allocate a dummy object at the end of the region to ensure that
132 // no more allocations can take place in it. However, sometimes we
133 // want to know where the end of the last "real" object we allocated
134 // into the region was and this is what this keeps track.
135 HeapWord* _pre_dummy_top;
136
137 public:
138 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
139 MemRegion mr);
140
141 void set_top(HeapWord* value) { _top = value; }
142 HeapWord* top() const { return _top; }
143
144 protected:
145 // Reset the G1OffsetTableContigSpace.
146 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
147
148 HeapWord** top_addr() { return &_top; }
149 // Allocation helpers (return NULL if full).
150 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
151 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
152
153 public:
154 void reset_after_compaction() { set_top(compaction_top()); }
155
156 size_t used() const { return byte_size(bottom(), top()); }
157 size_t free() const { return byte_size(top(), end()); }
158 bool is_free_block(const HeapWord* p) const { return p >= top(); }
159
160 MemRegion used_region() const { return MemRegion(bottom(), top()); }
161
162 void object_iterate(ObjectClosure* blk);
163 void safe_object_iterate(ObjectClosure* blk);
164
165 void set_bottom(HeapWord* value);
166 void set_end(HeapWord* value);
167
168 virtual HeapWord* saved_mark_word() const;
169 void record_top_and_timestamp();
170 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
171 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
172
173 // See the comment above in the declaration of _pre_dummy_top for an
174 // explanation of what it is.
175 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
176 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
177 _pre_dummy_top = pre_dummy_top;
178 }
179 HeapWord* pre_dummy_top() {
180 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
181 }
182 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
183
184 virtual void clear(bool mangle_space);
185
186 HeapWord* block_start(const void* p);
187 HeapWord* block_start_const(const void* p) const;
188
189 void prepare_for_compaction(CompactPoint* cp);
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.reset_bot();
203 }
204
205 void print_bot_on(outputStream* out) {
206 _offsets.print_on(out);
207 }
208 };
209
210 class HeapRegion: public G1OffsetTableContigSpace {
211 friend class VMStructs;
212 private:
213
214 // The remembered set for this region.
215 // (Might want to make this "inline" later, to avoid some alloc failure
216 // issues.)
217 HeapRegionRemSet* _rem_set;
218
219 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
220
221 protected:
222 // The index of this region in the heap region sequence.
223 uint _hrm_index;
224
225 HeapRegionType _type;
226
227 // For a humongous region, region in which it starts.
228 HeapRegion* _humongous_start_region;
229 // For the start region of a humongous sequence, it's original end().
230 HeapWord* _orig_end;
231
232 // True iff the region is in current collection_set.
233 bool _in_collection_set;
234
235 // True iff an attempt to evacuate an object in the region failed.
236 bool _evacuation_failed;
237
238 // A heap region may be a member one of a number of special subsets, each
239 // represented as linked lists through the field below. Currently, there
240 // is only one set:
241 // The collection set.
242 HeapRegion* _next_in_special_set;
243
244 // next region in the young "generation" region set
245 HeapRegion* _next_young_region;
246
247 // Next region whose cards need cleaning
248 HeapRegion* _next_dirty_cards_region;
249
250 // Fields used by the HeapRegionSetBase class and subclasses.
251 HeapRegion* _next;
252 HeapRegion* _prev;
253 #ifdef ASSERT
254 HeapRegionSetBase* _containing_set;
255 #endif // ASSERT
256
257 // We use concurrent marking to determine the amount of live data
258 // in each heap region.
259 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
260 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
261
262 // The calculated GC efficiency of the region.
263 double _gc_efficiency;
264
265 int _young_index_in_cset;
266 SurvRateGroup* _surv_rate_group;
267 int _age_index;
268
269 // The start of the unmarked area. The unmarked area extends from this
270 // word until the top and/or end of the region, and is the part
271 // of the region for which no marking was done, i.e. objects may
272 // have been allocated in this part since the last mark phase.
273 // "prev" is the top at the start of the last completed marking.
274 // "next" is the top at the start of the in-progress marking (if any.)
275 HeapWord* _prev_top_at_mark_start;
276 HeapWord* _next_top_at_mark_start;
277 // If a collection pause is in progress, this is the top at the start
278 // of that pause.
279
280 void init_top_at_mark_start() {
281 assert(_prev_marked_bytes == 0 &&
282 _next_marked_bytes == 0,
283 "Must be called after zero_marked_bytes.");
284 HeapWord* bot = bottom();
285 _prev_top_at_mark_start = bot;
286 _next_top_at_mark_start = bot;
287 }
288
289 // Cached attributes used in the collection set policy information
290
291 // The RSet length that was added to the total value
292 // for the collection set.
293 size_t _recorded_rs_length;
294
295 // The predicted elapsed time that was added to total value
296 // for the collection set.
297 double _predicted_elapsed_time_ms;
298
299 // The predicted number of bytes to copy that was added to
300 // the total value for the collection set.
301 size_t _predicted_bytes_to_copy;
302
303 public:
304 HeapRegion(uint hrm_index,
305 G1BlockOffsetSharedArray* sharedOffsetArray,
306 MemRegion mr);
307
308 // Initializing the HeapRegion not only resets the data structure, but also
309 // resets the BOT for that heap region.
310 // The default values for clear_space means that we will do the clearing if
311 // there's clearing to be done ourselves. We also always mangle the space.
312 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
313
314 static int LogOfHRGrainBytes;
315 static int LogOfHRGrainWords;
316
317 static size_t GrainBytes;
318 static size_t GrainWords;
319 static size_t CardsPerRegion;
320
321 static size_t align_up_to_region_byte_size(size_t sz) {
322 return (sz + (size_t) GrainBytes - 1) &
323 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
324 }
325
326 static size_t max_region_size();
327
328 // It sets up the heap region size (GrainBytes / GrainWords), as
329 // well as other related fields that are based on the heap region
330 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
331 // CardsPerRegion). All those fields are considered constant
332 // throughout the JVM's execution, therefore they should only be set
333 // up once during initialization time.
334 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
335
336 // All allocated blocks are occupied by objects in a HeapRegion
337 bool block_is_obj(const HeapWord* p) const;
338
339 // Returns the object size for all valid block starts
340 // and the amount of unallocated words if called on top()
341 size_t block_size(const HeapWord* p) const;
342
343 inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
344 inline HeapWord* allocate_no_bot_updates(size_t word_size);
345
346 // If this region is a member of a HeapRegionManager, the index in that
347 // sequence, otherwise -1.
348 uint hrm_index() const { return _hrm_index; }
349
350 // The number of bytes marked live in the region in the last marking phase.
351 size_t marked_bytes() { return _prev_marked_bytes; }
352 size_t live_bytes() {
353 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
354 }
355
356 // The number of bytes counted in the next marking.
357 size_t next_marked_bytes() { return _next_marked_bytes; }
358 // The number of bytes live wrt the next marking.
359 size_t next_live_bytes() {
360 return
361 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
362 }
363
364 // A lower bound on the amount of garbage bytes in the region.
365 size_t garbage_bytes() {
366 size_t used_at_mark_start_bytes =
367 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
368 assert(used_at_mark_start_bytes >= marked_bytes(),
369 "Can't mark more than we have.");
370 return used_at_mark_start_bytes - marked_bytes();
371 }
372
373 // Return the amount of bytes we'll reclaim if we collect this
374 // region. This includes not only the known garbage bytes in the
375 // region but also any unallocated space in it, i.e., [top, end),
376 // since it will also be reclaimed if we collect the region.
377 size_t reclaimable_bytes() {
378 size_t known_live_bytes = live_bytes();
379 assert(known_live_bytes <= capacity(), "sanity");
380 return capacity() - known_live_bytes;
381 }
382
383 // An upper bound on the number of live bytes in the region.
384 size_t max_live_bytes() { return used() - garbage_bytes(); }
385
386 void add_to_marked_bytes(size_t incr_bytes) {
387 _next_marked_bytes = _next_marked_bytes + incr_bytes;
388 assert(_next_marked_bytes <= used(), "invariant" );
389 }
390
391 void zero_marked_bytes() {
392 _prev_marked_bytes = _next_marked_bytes = 0;
393 }
394
395 const char* get_type_str() const { return _type.get_str(); }
396 const char* get_short_type_str() const { return _type.get_short_str(); }
397
398 bool is_free() const { return _type.is_free(); }
399
400 bool is_young() const { return _type.is_young(); }
401 bool is_eden() const { return _type.is_eden(); }
402 bool is_survivor() const { return _type.is_survivor(); }
403
404 bool isHumongous() const { return _type.is_humongous(); }
405 bool startsHumongous() const { return _type.is_starts_humongous(); }
406 bool continuesHumongous() const { return _type.is_continues_humongous(); }
407
408 bool is_old() const { return _type.is_old(); }
409
410 // For a humongous region, region in which it starts.
411 HeapRegion* humongous_start_region() const {
412 return _humongous_start_region;
413 }
414
415 // Return the number of distinct regions that are covered by this region:
416 // 1 if the region is not humongous, >= 1 if the region is humongous.
417 uint region_num() const {
418 if (!isHumongous()) {
419 return 1U;
420 } else {
421 assert(startsHumongous(), "doesn't make sense on HC regions");
422 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
423 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
424 }
425 }
426
427 // Return the index + 1 of the last HC regions that's associated
428 // with this HS region.
429 uint last_hc_index() const {
430 assert(startsHumongous(), "don't call this otherwise");
431 return hrm_index() + region_num();
432 }
433
434 // Same as Space::is_in_reserved, but will use the original size of the region.
435 // The original size is different only for start humongous regions. They get
436 // their _end set up to be the end of the last continues region of the
437 // 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 clear_humongous();
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 and prev fields used to link regions into
503 // linked lists.
504 HeapRegion* next() { return _next; }
505 HeapRegion* prev() { return _prev; }
506
507 void set_next(HeapRegion* next) { _next = next; }
508 void set_prev(HeapRegion* prev) { _prev = prev; }
509
510 // Every region added to a set is tagged with a reference to that
511 // set. This is used for doing consistency checking to make sure that
512 // the contents of a set are as they should be and it's only
513 // available in non-product builds.
514 #ifdef ASSERT
515 void set_containing_set(HeapRegionSetBase* containing_set) {
516 assert((containing_set == NULL && _containing_set != NULL) ||
517 (containing_set != NULL && _containing_set == NULL),
518 err_msg("containing_set: "PTR_FORMAT" "
519 "_containing_set: "PTR_FORMAT,
520 p2i(containing_set), p2i(_containing_set)));
521
522 _containing_set = containing_set;
523 }
524
525 HeapRegionSetBase* containing_set() { return _containing_set; }
526 #else // ASSERT
527 void set_containing_set(HeapRegionSetBase* containing_set) { }
528
529 // containing_set() is only used in asserts so there's no reason
530 // to provide a dummy version of it.
531 #endif // ASSERT
532
533 HeapRegion* get_next_young_region() { return _next_young_region; }
534 void set_next_young_region(HeapRegion* hr) {
535 _next_young_region = hr;
536 }
537
538 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
539 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
540 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
541 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
542
543 HeapWord* orig_end() const { return _orig_end; }
544
545 // Reset HR stuff to default values.
546 void hr_clear(bool par, bool clear_space, bool locked = false);
547 void par_clear();
548
549 // Get the start of the unmarked area in this region.
550 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
551 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
552
553 // Note the start or end of marking. This tells the heap region
554 // that the collector is about to start or has finished (concurrently)
555 // marking the heap.
556
557 // Notify the region that concurrent marking is starting. Initialize
558 // all fields related to the next marking info.
559 inline void note_start_of_marking();
560
561 // Notify the region that concurrent marking has finished. Copy the
562 // (now finalized) next marking info fields into the prev marking
563 // info fields.
564 inline void note_end_of_marking();
565
566 // Notify the region that it will be used as to-space during a GC
567 // and we are about to start copying objects into it.
568 inline void note_start_of_copying(bool during_initial_mark);
569
570 // Notify the region that it ceases being to-space during a GC and
571 // we will not copy objects into it any more.
572 inline void note_end_of_copying(bool during_initial_mark);
573
574 // Notify the region that we are about to start processing
575 // self-forwarded objects during evac failure handling.
576 void note_self_forwarding_removal_start(bool during_initial_mark,
577 bool during_conc_mark);
578
579 // Notify the region that we have finished processing self-forwarded
580 // objects during evac failure handling.
581 void note_self_forwarding_removal_end(bool during_initial_mark,
582 bool during_conc_mark,
583 size_t marked_bytes);
584
585 // Returns "false" iff no object in the region was allocated when the
586 // last mark phase ended.
587 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
588
589 void reset_during_compaction() {
590 assert(isHumongous() && startsHumongous(),
591 "should only be called for starts humongous regions");
592
593 zero_marked_bytes();
594 init_top_at_mark_start();
595 }
596
597 void calc_gc_efficiency(void);
598 double gc_efficiency() { return _gc_efficiency;}
599
600 int young_index_in_cset() const { return _young_index_in_cset; }
601 void set_young_index_in_cset(int index) {
602 assert( (index == -1) || is_young(), "pre-condition" );
603 _young_index_in_cset = index;
604 }
605
606 int age_in_surv_rate_group() {
607 assert( _surv_rate_group != NULL, "pre-condition" );
608 assert( _age_index > -1, "pre-condition" );
609 return _surv_rate_group->age_in_group(_age_index);
610 }
611
612 void record_surv_words_in_group(size_t words_survived) {
613 assert( _surv_rate_group != NULL, "pre-condition" );
614 assert( _age_index > -1, "pre-condition" );
615 int age_in_group = age_in_surv_rate_group();
616 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
617 }
618
619 int age_in_surv_rate_group_cond() {
620 if (_surv_rate_group != NULL)
621 return age_in_surv_rate_group();
622 else
623 return -1;
624 }
625
626 SurvRateGroup* surv_rate_group() {
627 return _surv_rate_group;
628 }
629
630 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
631 assert( surv_rate_group != NULL, "pre-condition" );
632 assert( _surv_rate_group == NULL, "pre-condition" );
633 assert( is_young(), "pre-condition" );
634
635 _surv_rate_group = surv_rate_group;
636 _age_index = surv_rate_group->next_age_index();
637 }
638
639 void uninstall_surv_rate_group() {
640 if (_surv_rate_group != NULL) {
641 assert( _age_index > -1, "pre-condition" );
642 assert( is_young(), "pre-condition" );
643
644 _surv_rate_group = NULL;
645 _age_index = -1;
646 } else {
647 assert( _age_index == -1, "pre-condition" );
648 }
649 }
650
651 void set_free() { _type.set_free(); }
652
653 void set_eden() { _type.set_eden(); }
654 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
655 void set_survivor() { _type.set_survivor(); }
656
657 void set_old() { _type.set_old(); }
658
659 // Determine if an object has been allocated since the last
660 // mark performed by the collector. This returns true iff the object
661 // is within the unmarked area of the region.
662 bool obj_allocated_since_prev_marking(oop obj) const {
663 return (HeapWord *) obj >= prev_top_at_mark_start();
664 }
665 bool obj_allocated_since_next_marking(oop obj) const {
666 return (HeapWord *) obj >= next_top_at_mark_start();
667 }
668
669 // Returns the "evacuation_failed" property of the region.
670 bool evacuation_failed() { return _evacuation_failed; }
671
672 // Sets the "evacuation_failed" property of the region.
673 void set_evacuation_failed(bool b) {
674 _evacuation_failed = b;
675
676 if (b) {
677 _next_marked_bytes = 0;
678 }
679 }
680
681 // Requires that "mr" be entirely within the region.
682 // Apply "cl->do_object" to all objects that intersect with "mr".
683 // If the iteration encounters an unparseable portion of the region,
684 // or if "cl->abort()" is true after a closure application,
685 // terminate the iteration and return the address of the start of the
686 // subregion that isn't done. (The two can be distinguished by querying
687 // "cl->abort()".) Return of "NULL" indicates that the iteration
688 // completed.
689 HeapWord*
690 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
691
692 // filter_young: if true and the region is a young region then we
693 // skip the iteration.
694 // card_ptr: if not NULL, and we decide that the card is not young
695 // and we iterate over it, we'll clean the card before we start the
696 // iteration.
697 HeapWord*
698 oops_on_card_seq_iterate_careful(MemRegion mr,
699 FilterOutOfRegionClosure* cl,
700 bool filter_young,
701 jbyte* card_ptr);
702
703 size_t recorded_rs_length() const { return _recorded_rs_length; }
704 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
705 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
706
707 void set_recorded_rs_length(size_t rs_length) {
708 _recorded_rs_length = rs_length;
709 }
710
711 void set_predicted_elapsed_time_ms(double ms) {
712 _predicted_elapsed_time_ms = ms;
713 }
714
715 void set_predicted_bytes_to_copy(size_t bytes) {
716 _predicted_bytes_to_copy = bytes;
717 }
718
719 virtual CompactibleSpace* next_compaction_space() const;
720
721 virtual void reset_after_compaction();
722
723 // Routines for managing a list of code roots (attached to the
724 // this region's RSet) that point into this heap region.
725 void add_strong_code_root(nmethod* nm);
726 void add_strong_code_root_locked(nmethod* nm);
727 void remove_strong_code_root(nmethod* nm);
728
729 // Applies blk->do_code_blob() to each of the entries in
730 // the strong code roots list for this region
731 void strong_code_roots_do(CodeBlobClosure* blk) const;
732
733 // Verify that the entries on the strong code root list for this
734 // region are live and include at least one pointer into this region.
735 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
736
737 void print() const;
738 void print_on(outputStream* st) const;
739
740 // vo == UsePrevMarking -> use "prev" marking information,
741 // vo == UseNextMarking -> use "next" marking information
742 // vo == UseMarkWord -> use the mark word in the object header
743 //
744 // NOTE: Only the "prev" marking information is guaranteed to be
745 // consistent most of the time, so most calls to this should use
746 // vo == UsePrevMarking.
747 // Currently, there is only one case where this is called with
748 // vo == UseNextMarking, which is to verify the "next" marking
749 // information at the end of remark.
750 // Currently there is only one place where this is called with
751 // vo == UseMarkWord, which is to verify the marking during a
752 // full GC.
753 void verify(VerifyOption vo, bool *failures) const;
754
755 // Override; it uses the "prev" marking information
756 virtual void verify() const;
757 };
758
759 // HeapRegionClosure is used for iterating over regions.
760 // Terminates the iteration when the "doHeapRegion" method returns "true".
761 class HeapRegionClosure : public StackObj {
762 friend class HeapRegionManager;
763 friend class G1CollectedHeap;
764
765 bool _complete;
766 void incomplete() { _complete = false; }
767
768 public:
769 HeapRegionClosure(): _complete(true) {}
770
771 // Typically called on each region until it returns true.
772 virtual bool doHeapRegion(HeapRegion* r) = 0;
773
774 // True after iteration if the closure was applied to all heap regions
775 // and returned "false" in all cases.
776 bool complete() { return _complete; }
777 };
778
779 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP