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.
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
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/g1AllocationContext.hpp"
29 #include "gc_implementation/g1/g1BlockOffsetTable.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 private:
70 HeapRegion* _hr;
71 G1ParPushHeapRSClosure* _rs_scan;
72 G1CollectedHeap* _g1;
73
74 // Walk the given memory region from bottom to (actual) top
75 // looking for objects and applying the oop closure (_cl) to
76 // them. The base implementation of this treats the area as
77 // blocks, where a block may or may not be an object. Sub-
78 // classes should override this to provide more accurate
79 // or possibly more efficient walking.
80 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
81
82 public:
83 HeapRegionDCTOC(G1CollectedHeap* g1,
84 HeapRegion* hr,
85 G1ParPushHeapRSClosure* cl,
86 CardTableModRefBS::PrecisionStyle precision);
87 };
88
89 // The complicating factor is that BlockOffsetTable diverged
90 // significantly, and we need functionality that is only in the G1 version.
91 // So I copied that code, which led to an alternate G1 version of
92 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
93 // be reconciled, then G1OffsetTableContigSpace could go away.
94
95 // The idea behind time stamps is the following. We want to keep track of
96 // the highest address where it's safe to scan objects for each region.
97 // This is only relevant for current GC alloc regions so we keep a time stamp
98 // per region to determine if the region has been allocated during the current
99 // GC or not. If the time stamp is current we report a scan_top value which
100 // was saved at the end of the previous GC for retained alloc regions and which is
101 // equal to the bottom for all other regions.
102 // There is a race between card scanners and allocating gc workers where we must ensure
103 // that card scanners do not read the memory allocated by the gc workers.
104 // In order to enforce that, we must not return a value of _top which is more recent than the
105 // time stamp. This is due to the fact that a region may become a gc alloc region at
106 // some point after we've read the timestamp value as being < the current time stamp.
107 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
108 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
109 // evacuation pauses between two cleanups, which is _highly_ unlikely.
110 class G1OffsetTableContigSpace: public CompactibleSpace {
111 friend class VMStructs;
112 HeapWord* _top;
113 HeapWord* volatile _scan_top;
114 protected:
115 G1BlockOffsetArrayContigSpace _offsets;
116 Mutex _par_alloc_lock;
117 volatile unsigned _gc_time_stamp;
118 // When we need to retire an allocation region, while other threads
119 // are also concurrently trying to allocate into it, we typically
120 // allocate a dummy object at the end of the region to ensure that
121 // no more allocations can take place in it. However, sometimes we
122 // want to know where the end of the last "real" object we allocated
123 // into the region was and this is what this keeps track.
124 HeapWord* _pre_dummy_top;
125
126 public:
127 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
128 MemRegion mr);
129
130 void set_top(HeapWord* value) { _top = value; }
131 HeapWord* top() const { return _top; }
132
133 protected:
134 // Reset the G1OffsetTableContigSpace.
135 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
136
137 HeapWord** top_addr() { return &_top; }
138 // Allocation helpers (return NULL if full).
139 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
140 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
141
142 public:
143 void reset_after_compaction() { set_top(compaction_top()); }
144
145 size_t used() const { return byte_size(bottom(), top()); }
146 size_t free() const { return byte_size(top(), end()); }
147 bool is_free_block(const HeapWord* p) const { return p >= top(); }
148
149 MemRegion used_region() const { return MemRegion(bottom(), top()); }
150
151 void object_iterate(ObjectClosure* blk);
152 void safe_object_iterate(ObjectClosure* blk);
153
154 void set_bottom(HeapWord* value);
155 void set_end(HeapWord* value);
156
157 void mangle_unused_area() PRODUCT_RETURN;
158 void mangle_unused_area_complete() PRODUCT_RETURN;
159
160 HeapWord* scan_top() const;
161 void record_timestamp();
162 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
163 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
164 void record_retained_region();
165
166 // See the comment above in the declaration of _pre_dummy_top for an
167 // explanation of what it is.
168 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
169 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
170 _pre_dummy_top = pre_dummy_top;
171 }
172 HeapWord* pre_dummy_top() {
173 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
174 }
175 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
176
177 virtual void clear(bool mangle_space);
178
179 HeapWord* block_start(const void* p);
180 HeapWord* block_start_const(const void* p) const;
181
182 // Add offset table update.
183 virtual HeapWord* allocate(size_t word_size);
184 HeapWord* par_allocate(size_t word_size);
185
186 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
187
188 // MarkSweep support phase3
189 virtual HeapWord* initialize_threshold();
190 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
191
192 virtual void print() const;
193
194 void reset_bot() {
195 _offsets.reset_bot();
196 }
197
198 void print_bot_on(outputStream* out) {
199 _offsets.print_on(out);
200 }
201 };
202
203 class HeapRegion: public G1OffsetTableContigSpace {
204 friend class VMStructs;
205 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
206 template <typename SpaceType>
207 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
208 private:
209
210 // The remembered set for this region.
211 // (Might want to make this "inline" later, to avoid some alloc failure
212 // issues.)
213 HeapRegionRemSet* _rem_set;
214
215 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
216
217 // Auxiliary functions for scan_and_forward support.
218 // See comments for CompactibleSpace for more information.
219 inline HeapWord* scan_limit() const {
220 return top();
221 }
222
223 inline bool scanned_block_is_obj(const HeapWord* addr) const {
224 return true; // Always true, since scan_limit is top
225 }
226
227 inline size_t scanned_block_size(const HeapWord* addr) const {
228 return HeapRegion::block_size(addr); // Avoid virtual call
229 }
230
231 protected:
232 // The index of this region in the heap region sequence.
233 uint _hrm_index;
234
235 AllocationContext_t _allocation_context;
236
237 HeapRegionType _type;
238
239 // For a humongous region, region in which it starts.
240 HeapRegion* _humongous_start_region;
241
242 // True iff an attempt to evacuate an object in the region failed.
243 bool _evacuation_failed;
244
245 // A heap region may be a member one of a number of special subsets, each
246 // represented as linked lists through the field below. Currently, there
247 // is only one set:
248 // The collection set.
249 HeapRegion* _next_in_special_set;
250
251 // next region in the young "generation" region set
252 HeapRegion* _next_young_region;
253
254 // Next region whose cards need cleaning
255 HeapRegion* _next_dirty_cards_region;
256
257 // Fields used by the HeapRegionSetBase class and subclasses.
258 HeapRegion* _next;
259 HeapRegion* _prev;
260 #ifdef ASSERT
261 HeapRegionSetBase* _containing_set;
262 #endif // ASSERT
263
264 // We use concurrent marking to determine the amount of live data
265 // in each heap region.
266 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
267 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
268
269 // The calculated GC efficiency of the region.
270 double _gc_efficiency;
271
272 int _young_index_in_cset;
273 SurvRateGroup* _surv_rate_group;
274 int _age_index;
275
276 // The start of the unmarked area. The unmarked area extends from this
277 // word until the top and/or end of the region, and is the part
278 // of the region for which no marking was done, i.e. objects may
279 // have been allocated in this part since the last mark phase.
280 // "prev" is the top at the start of the last completed marking.
281 // "next" is the top at the start of the in-progress marking (if any.)
282 HeapWord* _prev_top_at_mark_start;
283 HeapWord* _next_top_at_mark_start;
284 // If a collection pause is in progress, this is the top at the start
285 // of that pause.
286
287 void init_top_at_mark_start() {
288 assert(_prev_marked_bytes == 0 &&
289 _next_marked_bytes == 0,
290 "Must be called after zero_marked_bytes.");
291 HeapWord* bot = bottom();
292 _prev_top_at_mark_start = bot;
293 _next_top_at_mark_start = bot;
294 }
295
296 // Cached attributes used in the collection set policy information
297
298 // The RSet length that was added to the total value
299 // for the collection set.
300 size_t _recorded_rs_length;
301
302 // The predicted elapsed time that was added to total value
303 // for the collection set.
304 double _predicted_elapsed_time_ms;
305
306 // The predicted number of bytes to copy that was added to
307 // the total value for the collection set.
308 size_t _predicted_bytes_to_copy;
309
310 public:
311 HeapRegion(uint hrm_index,
312 G1BlockOffsetSharedArray* sharedOffsetArray,
313 MemRegion mr);
314
315 // Initializing the HeapRegion not only resets the data structure, but also
316 // resets the BOT for that heap region.
317 // The default values for clear_space means that we will do the clearing if
318 // there's clearing to be done ourselves. We also always mangle the space.
319 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
320
321 static int LogOfHRGrainBytes;
322 static int LogOfHRGrainWords;
323
324 static size_t GrainBytes;
325 static size_t GrainWords;
326 static size_t CardsPerRegion;
327
328 static size_t align_up_to_region_byte_size(size_t sz) {
329 return (sz + (size_t) GrainBytes - 1) &
330 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
331 }
332
333 static size_t max_region_size();
334
335 // It sets up the heap region size (GrainBytes / GrainWords), as
336 // well as other related fields that are based on the heap region
337 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
338 // CardsPerRegion). All those fields are considered constant
339 // throughout the JVM's execution, therefore they should only be set
340 // up once during initialization time.
341 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
342
343 // All allocated blocks are occupied by objects in a HeapRegion
344 bool block_is_obj(const HeapWord* p) const;
345
346 // Returns the object size for all valid block starts
347 // and the amount of unallocated words if called on top()
348 size_t block_size(const HeapWord* p) const;
349
350 // Override for scan_and_forward support.
351 void prepare_for_compaction(CompactPoint* cp);
352
353 inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
354 inline HeapWord* allocate_no_bot_updates(size_t word_size);
355
356 // If this region is a member of a HeapRegionManager, the index in that
357 // sequence, otherwise -1.
358 uint hrm_index() const { return _hrm_index; }
359
360 // The number of bytes marked live in the region in the last marking phase.
361 size_t marked_bytes() { return _prev_marked_bytes; }
362 size_t live_bytes() {
363 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
364 }
365
366 // The number of bytes counted in the next marking.
367 size_t next_marked_bytes() { return _next_marked_bytes; }
368 // The number of bytes live wrt the next marking.
369 size_t next_live_bytes() {
370 return
371 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
372 }
373
374 // A lower bound on the amount of garbage bytes in the region.
375 size_t garbage_bytes() {
376 size_t used_at_mark_start_bytes =
377 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
378 assert(used_at_mark_start_bytes >= marked_bytes(),
379 "Can't mark more than we have.");
380 return used_at_mark_start_bytes - marked_bytes();
381 }
382
383 // Return the amount of bytes we'll reclaim if we collect this
384 // region. This includes not only the known garbage bytes in the
385 // region but also any unallocated space in it, i.e., [top, end),
386 // since it will also be reclaimed if we collect the region.
387 size_t reclaimable_bytes() {
388 size_t known_live_bytes = live_bytes();
389 assert(known_live_bytes <= capacity(), "sanity");
390 return capacity() - known_live_bytes;
391 }
392
393 // An upper bound on the number of live bytes in the region.
394 size_t max_live_bytes() { return used() - garbage_bytes(); }
395
396 void add_to_marked_bytes(size_t incr_bytes) {
397 _next_marked_bytes = _next_marked_bytes + incr_bytes;
398 assert(_next_marked_bytes <= used(), "invariant" );
399 }
400
401 void zero_marked_bytes() {
402 _prev_marked_bytes = _next_marked_bytes = 0;
403 }
404
405 const char* get_type_str() const { return _type.get_str(); }
406 const char* get_short_type_str() const { return _type.get_short_str(); }
407
408 bool is_free() const { return _type.is_free(); }
409
410 bool is_young() const { return _type.is_young(); }
411 bool is_eden() const { return _type.is_eden(); }
412 bool is_survivor() const { return _type.is_survivor(); }
413
414 bool is_humongous() const { return _type.is_humongous(); }
415 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
416 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
417
418 bool is_old() const { return _type.is_old(); }
419
420 // For a humongous region, region in which it starts.
421 HeapRegion* humongous_start_region() const {
422 return _humongous_start_region;
423 }
424
425 // Return the number of distinct regions that are covered by this region:
426 // 1 if the region is not humongous, >= 1 if the region is humongous.
427 uint region_num() const {
428 if (!is_humongous()) {
429 return 1U;
430 } else {
431 assert(is_starts_humongous(), "doesn't make sense on HC regions");
432 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
433 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
434 }
435 }
436
437 // Return the index + 1 of the last HC regions that's associated
438 // with this HS region.
439 uint last_hc_index() const {
440 assert(is_starts_humongous(), "don't call this otherwise");
441 return hrm_index() + region_num();
442 }
443
444 // Same as Space::is_in_reserved, but will use the original size of the region.
445 // The original size is different only for start humongous regions. They get
446 // their _end set up to be the end of the last continues region of the
447 // corresponding humongous object.
448 bool is_in_reserved_raw(const void* p) const {
449 return _bottom <= p && p < orig_end();
450 }
451
452 // Makes the current region be a "starts humongous" region, i.e.,
453 // the first region in a series of one or more contiguous regions
454 // that will contain a single "humongous" object. The two parameters
455 // are as follows:
456 //
457 // new_top : The new value of the top field of this region which
458 // points to the end of the humongous object that's being
459 // allocated. If there is more than one region in the series, top
460 // will lie beyond this region's original end field and on the last
461 // region in the series.
462 //
463 // new_end : The new value of the end field of this region which
464 // points to the end of the last region in the series. If there is
465 // one region in the series (namely: this one) end will be the same
466 // as the original end of this region.
467 //
468 // Updating top and end as described above makes this region look as
469 // if it spans the entire space taken up by all the regions in the
470 // series and an single allocation moved its top to new_top. This
471 // ensures that the space (capacity / allocated) taken up by all
472 // humongous regions can be calculated by just looking at the
473 // "starts humongous" regions and by ignoring the "continues
474 // humongous" regions.
475 void set_starts_humongous(HeapWord* new_top, HeapWord* new_end);
476
477 // Makes the current region be a "continues humongous'
478 // region. first_hr is the "start humongous" region of the series
479 // which this region will be part of.
480 void set_continues_humongous(HeapRegion* first_hr);
481
482 // Unsets the humongous-related fields on the region.
483 void clear_humongous();
484
485 // If the region has a remembered set, return a pointer to it.
486 HeapRegionRemSet* rem_set() const {
487 return _rem_set;
488 }
489
490 bool in_collection_set() const;
491
492 HeapRegion* next_in_collection_set() {
493 assert(in_collection_set(), "should only invoke on member of CS.");
494 assert(_next_in_special_set == NULL ||
495 _next_in_special_set->in_collection_set(),
496 "Malformed CS.");
497 return _next_in_special_set;
498 }
499 void set_next_in_collection_set(HeapRegion* r) {
500 assert(in_collection_set(), "should only invoke on member of CS.");
501 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
502 _next_in_special_set = r;
503 }
504
505 void set_allocation_context(AllocationContext_t context) {
506 _allocation_context = context;
507 }
508
509 AllocationContext_t allocation_context() const {
510 return _allocation_context;
511 }
512
513 // Methods used by the HeapRegionSetBase class and subclasses.
514
515 // Getter and setter for the next and prev fields used to link regions into
516 // linked lists.
517 HeapRegion* next() { return _next; }
518 HeapRegion* prev() { return _prev; }
519
520 void set_next(HeapRegion* next) { _next = next; }
521 void set_prev(HeapRegion* prev) { _prev = prev; }
522
523 // Every region added to a set is tagged with a reference to that
524 // set. This is used for doing consistency checking to make sure that
525 // the contents of a set are as they should be and it's only
526 // available in non-product builds.
527 #ifdef ASSERT
528 void set_containing_set(HeapRegionSetBase* containing_set) {
529 assert((containing_set == NULL && _containing_set != NULL) ||
530 (containing_set != NULL && _containing_set == NULL),
531 err_msg("containing_set: "PTR_FORMAT" "
532 "_containing_set: "PTR_FORMAT,
533 p2i(containing_set), p2i(_containing_set)));
534
535 _containing_set = containing_set;
536 }
537
538 HeapRegionSetBase* containing_set() { return _containing_set; }
539 #else // ASSERT
540 void set_containing_set(HeapRegionSetBase* containing_set) { }
541
542 // containing_set() is only used in asserts so there's no reason
543 // to provide a dummy version of it.
544 #endif // ASSERT
545
546 HeapRegion* get_next_young_region() { return _next_young_region; }
547 void set_next_young_region(HeapRegion* hr) {
548 _next_young_region = hr;
549 }
550
551 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
552 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
553 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
554 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
555
556 // For the start region of a humongous sequence, it's original end().
557 HeapWord* orig_end() const { return _bottom + GrainWords; }
558
559 // Reset HR stuff to default values.
560 void hr_clear(bool par, bool clear_space, bool locked = false);
561 void par_clear();
562
563 // Get the start of the unmarked area in this region.
564 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
565 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
566
567 // Note the start or end of marking. This tells the heap region
568 // that the collector is about to start or has finished (concurrently)
569 // marking the heap.
570
571 // Notify the region that concurrent marking is starting. Initialize
572 // all fields related to the next marking info.
573 inline void note_start_of_marking();
574
575 // Notify the region that concurrent marking has finished. Copy the
576 // (now finalized) next marking info fields into the prev marking
577 // info fields.
578 inline void note_end_of_marking();
579
580 // Notify the region that it will be used as to-space during a GC
581 // and we are about to start copying objects into it.
582 inline void note_start_of_copying(bool during_initial_mark);
583
584 // Notify the region that it ceases being to-space during a GC and
585 // we will not copy objects into it any more.
586 inline void note_end_of_copying(bool during_initial_mark);
587
588 // Notify the region that we are about to start processing
589 // self-forwarded objects during evac failure handling.
590 void note_self_forwarding_removal_start(bool during_initial_mark,
591 bool during_conc_mark);
592
593 // Notify the region that we have finished processing self-forwarded
594 // objects during evac failure handling.
595 void note_self_forwarding_removal_end(bool during_initial_mark,
596 bool during_conc_mark,
597 size_t marked_bytes);
598
599 // Returns "false" iff no object in the region was allocated when the
600 // last mark phase ended.
601 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
602
603 void reset_during_compaction() {
604 assert(is_starts_humongous(),
605 "should only be called for starts humongous regions");
606
607 zero_marked_bytes();
608 init_top_at_mark_start();
609 }
610
611 void calc_gc_efficiency(void);
612 double gc_efficiency() { return _gc_efficiency;}
613
614 int young_index_in_cset() const { return _young_index_in_cset; }
615 void set_young_index_in_cset(int index) {
616 assert( (index == -1) || is_young(), "pre-condition" );
617 _young_index_in_cset = index;
618 }
619
620 int age_in_surv_rate_group() {
621 assert( _surv_rate_group != NULL, "pre-condition" );
622 assert( _age_index > -1, "pre-condition" );
623 return _surv_rate_group->age_in_group(_age_index);
624 }
625
626 void record_surv_words_in_group(size_t words_survived) {
627 assert( _surv_rate_group != NULL, "pre-condition" );
628 assert( _age_index > -1, "pre-condition" );
629 int age_in_group = age_in_surv_rate_group();
630 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
631 }
632
633 int age_in_surv_rate_group_cond() {
634 if (_surv_rate_group != NULL)
635 return age_in_surv_rate_group();
636 else
637 return -1;
638 }
639
640 SurvRateGroup* surv_rate_group() {
641 return _surv_rate_group;
642 }
643
644 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
645 assert( surv_rate_group != NULL, "pre-condition" );
646 assert( _surv_rate_group == NULL, "pre-condition" );
647 assert( is_young(), "pre-condition" );
648
649 _surv_rate_group = surv_rate_group;
650 _age_index = surv_rate_group->next_age_index();
651 }
652
653 void uninstall_surv_rate_group() {
654 if (_surv_rate_group != NULL) {
655 assert( _age_index > -1, "pre-condition" );
656 assert( is_young(), "pre-condition" );
657
658 _surv_rate_group = NULL;
659 _age_index = -1;
660 } else {
661 assert( _age_index == -1, "pre-condition" );
662 }
663 }
664
665 void set_free() { _type.set_free(); }
666
667 void set_eden() { _type.set_eden(); }
668 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
669 void set_survivor() { _type.set_survivor(); }
670
671 void set_old() { _type.set_old(); }
672
673 // Determine if an object has been allocated since the last
674 // mark performed by the collector. This returns true iff the object
675 // is within the unmarked area of the region.
676 bool obj_allocated_since_prev_marking(oop obj) const {
677 return (HeapWord *) obj >= prev_top_at_mark_start();
678 }
679 bool obj_allocated_since_next_marking(oop obj) const {
680 return (HeapWord *) obj >= next_top_at_mark_start();
681 }
682
683 // Returns the "evacuation_failed" property of the region.
684 bool evacuation_failed() { return _evacuation_failed; }
685
686 // Sets the "evacuation_failed" property of the region.
687 void set_evacuation_failed(bool b) {
688 _evacuation_failed = b;
689
690 if (b) {
691 _next_marked_bytes = 0;
692 }
693 }
694
695 // Requires that "mr" be entirely within the region.
696 // Apply "cl->do_object" to all objects that intersect with "mr".
697 // If the iteration encounters an unparseable portion of the region,
698 // or if "cl->abort()" is true after a closure application,
699 // terminate the iteration and return the address of the start of the
700 // subregion that isn't done. (The two can be distinguished by querying
701 // "cl->abort()".) Return of "NULL" indicates that the iteration
702 // completed.
703 HeapWord*
704 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
705
706 // filter_young: if true and the region is a young region then we
707 // skip the iteration.
708 // card_ptr: if not NULL, and we decide that the card is not young
709 // and we iterate over it, we'll clean the card before we start the
710 // iteration.
711 HeapWord*
712 oops_on_card_seq_iterate_careful(MemRegion mr,
713 FilterOutOfRegionClosure* cl,
714 bool filter_young,
715 jbyte* card_ptr);
716
717 size_t recorded_rs_length() const { return _recorded_rs_length; }
718 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
719 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
720
721 void set_recorded_rs_length(size_t rs_length) {
722 _recorded_rs_length = rs_length;
723 }
724
725 void set_predicted_elapsed_time_ms(double ms) {
726 _predicted_elapsed_time_ms = ms;
727 }
728
729 void set_predicted_bytes_to_copy(size_t bytes) {
730 _predicted_bytes_to_copy = bytes;
731 }
732
733 virtual CompactibleSpace* next_compaction_space() const;
734
735 virtual void reset_after_compaction();
736
737 // Routines for managing a list of code roots (attached to the
738 // this region's RSet) that point into this heap region.
739 void add_strong_code_root(nmethod* nm);
740 void add_strong_code_root_locked(nmethod* nm);
741 void remove_strong_code_root(nmethod* nm);
742
743 // Applies blk->do_code_blob() to each of the entries in
744 // the strong code roots list for this region
745 void strong_code_roots_do(CodeBlobClosure* blk) const;
746
747 // Verify that the entries on the strong code root list for this
748 // region are live and include at least one pointer into this region.
749 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
750
751 void print() const;
752 void print_on(outputStream* st) const;
753
754 // vo == UsePrevMarking -> use "prev" marking information,
755 // vo == UseNextMarking -> use "next" marking information
756 // vo == UseMarkWord -> use the mark word in the object header
757 //
758 // NOTE: Only the "prev" marking information is guaranteed to be
759 // consistent most of the time, so most calls to this should use
760 // vo == UsePrevMarking.
761 // Currently, there is only one case where this is called with
762 // vo == UseNextMarking, which is to verify the "next" marking
763 // information at the end of remark.
764 // Currently there is only one place where this is called with
765 // vo == UseMarkWord, which is to verify the marking during a
766 // full GC.
767 void verify(VerifyOption vo, bool *failures) const;
768
769 // Override; it uses the "prev" marking information
770 virtual void verify() const;
771 };
772
773 // HeapRegionClosure is used for iterating over regions.
774 // Terminates the iteration when the "doHeapRegion" method returns "true".
775 class HeapRegionClosure : public StackObj {
776 friend class HeapRegionManager;
777 friend class G1CollectedHeap;
778
779 bool _complete;
780 void incomplete() { _complete = false; }
781
782 public:
783 HeapRegionClosure(): _complete(true) {}
784
785 // Typically called on each region until it returns true.
786 virtual bool doHeapRegion(HeapRegion* r) = 0;
787
788 // True after iteration if the closure was applied to all heap regions
789 // and returned "false" in all cases.
790 bool complete() { return _complete; }
791 };
792
793 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP