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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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/g1AllocationContext.hpp"
29 #include "gc_implementation/g1/g1BlockOffsetTable.hpp"
30 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
31 #include "gc_implementation/g1/heapRegionType.hpp"
32 #include "gc_implementation/g1/survRateGroup.hpp"
33 #include "gc_implementation/shared/ageTable.hpp"
34 #include "gc_implementation/shared/spaceDecorator.hpp"
35 #include "memory/space.inline.hpp"
36 #include "memory/watermark.hpp"
37 #include "utilities/macros.hpp"
38
39 // A HeapRegion is the smallest piece of a G1CollectedHeap that
40 // can be collected independently.
41
42 // NOTE: Although a HeapRegion is a Space, its
43 // Space::initDirtyCardClosure method must not be called.
44 // The problem is that the existence of this method breaks
45 // the independence of barrier sets from remembered sets.
46 // The solution is to remove this method from the definition
47 // of a Space.
48
49 class HeapRegionRemSet;
50 class HeapRegionRemSetIterator;
51 class HeapRegion;
52 class HeapRegionSetBase;
53 class nmethod;
54
55 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
56 #define HR_FORMAT_PARAMS(_hr_) \
57 (_hr_)->hrm_index(), \
58 (_hr_)->get_short_type_str(), \
59 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
60
61 // sentinel value for hrm_index
62 #define G1_NO_HRM_INDEX ((uint) -1)
63
64 // A dirty card to oop closure for heap regions. It
65 // knows how to get the G1 heap and how to use the bitmap
66 // in the concurrent marker used by G1 to filter remembered
67 // sets.
68
69 class HeapRegionDCTOC : public DirtyCardToOopClosure {
70 private:
71 HeapRegion* _hr;
72 G1ParPushHeapRSClosure* _rs_scan;
73 G1CollectedHeap* _g1;
74
75 // Walk the given memory region from bottom to (actual) top
76 // looking for objects and applying the oop closure (_cl) to
77 // them. The base implementation of this treats the area as
78 // blocks, where a block may or may not be an object. Sub-
79 // classes should override this to provide more accurate
80 // or possibly more efficient walking.
81 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
82
83 public:
84 HeapRegionDCTOC(G1CollectedHeap* g1,
85 HeapRegion* hr,
86 G1ParPushHeapRSClosure* cl,
87 CardTableModRefBS::PrecisionStyle precision);
88 };
89
90 // The complicating factor is that BlockOffsetTable diverged
91 // significantly, and we need functionality that is only in the G1 version.
92 // So I copied that code, which led to an alternate G1 version of
93 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
94 // be reconciled, then G1OffsetTableContigSpace could go away.
95
96 // The idea behind time stamps is the following. We want to keep track of
97 // the highest address where it's safe to scan objects for each region.
98 // This is only relevant for current GC alloc regions so we keep a time stamp
99 // per region to determine if the region has been allocated during the current
100 // GC or not. If the time stamp is current we report a scan_top value which
101 // was saved at the end of the previous GC for retained alloc regions and which is
102 // equal to the bottom for all other regions.
103 // There is a race between card scanners and allocating gc workers where we must ensure
104 // that card scanners do not read the memory allocated by the gc workers.
105 // In order to enforce that, we must not return a value of _top which is more recent than the
106 // time stamp. This is due to the fact that a region may become a gc alloc region at
107 // some point after we've read the timestamp value as being < the current time stamp.
108 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
109 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
110 // evacuation pauses between two cleanups, which is _highly_ unlikely.
111 class G1OffsetTableContigSpace: public CompactibleSpace {
112 friend class VMStructs;
113 HeapWord* _top;
114 HeapWord* volatile _scan_top;
115 protected:
116 G1BlockOffsetArrayContigSpace _offsets;
117 Mutex _par_alloc_lock;
118 volatile unsigned _gc_time_stamp;
119 // When we need to retire an allocation region, while other threads
120 // are also concurrently trying to allocate into it, we typically
121 // allocate a dummy object at the end of the region to ensure that
122 // no more allocations can take place in it. However, sometimes we
123 // want to know where the end of the last "real" object we allocated
124 // into the region was and this is what this keeps track.
125 HeapWord* _pre_dummy_top;
126
127 public:
128 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
129 MemRegion mr);
130
131 void set_top(HeapWord* value) { _top = value; }
132 HeapWord* top() const { return _top; }
133
134 protected:
135 // Reset the G1OffsetTableContigSpace.
136 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
137
138 HeapWord** top_addr() { return &_top; }
139 // Allocation helpers (return NULL if full).
140 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
141 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
142
143 public:
144 void reset_after_compaction() { set_top(compaction_top()); }
145
146 size_t used() const { return byte_size(bottom(), top()); }
147 size_t free() const { return byte_size(top(), end()); }
148 bool is_free_block(const HeapWord* p) const { return p >= top(); }
149
150 MemRegion used_region() const { return MemRegion(bottom(), top()); }
151
152 void object_iterate(ObjectClosure* blk);
153 void safe_object_iterate(ObjectClosure* blk);
154
155 void set_bottom(HeapWord* value);
156 void set_end(HeapWord* value);
157
158 void mangle_unused_area() PRODUCT_RETURN;
159 void mangle_unused_area_complete() PRODUCT_RETURN;
160
161 HeapWord* scan_top() const;
162 void record_timestamp();
163 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
164 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
165 void record_retained_region();
166
167 // See the comment above in the declaration of _pre_dummy_top for an
168 // explanation of what it is.
169 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
170 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
171 _pre_dummy_top = pre_dummy_top;
172 }
173 HeapWord* pre_dummy_top() {
174 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
175 }
176 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
177
178 virtual void clear(bool mangle_space);
179
180 HeapWord* block_start(const void* p);
181 HeapWord* block_start_const(const void* p) const;
182
183 // Add offset table update.
184 virtual HeapWord* allocate(size_t word_size);
185 HeapWord* par_allocate(size_t word_size);
186
187 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
188
189 // MarkSweep support phase3
190 virtual HeapWord* initialize_threshold();
191 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
192
193 virtual void print() const;
194
195 void reset_bot() {
196 _offsets.reset_bot();
197 }
198
199 void print_bot_on(outputStream* out) {
200 _offsets.print_on(out);
201 }
202 };
203
204 class HeapRegion: public G1OffsetTableContigSpace {
205 friend class VMStructs;
206 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
207 template <typename SpaceType>
208 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
209 private:
210
211 // The remembered set for this region.
212 // (Might want to make this "inline" later, to avoid some alloc failure
213 // issues.)
214 HeapRegionRemSet* _rem_set;
215
216 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
217
218 // Auxiliary functions for scan_and_forward support.
219 // See comments for CompactibleSpace for more information.
220 inline HeapWord* scan_limit() const {
221 return top();
222 }
223
224 inline bool scanned_block_is_obj(const HeapWord* addr) const {
225 return true; // Always true, since scan_limit is top
226 }
227
228 inline size_t scanned_block_size(const HeapWord* addr) const {
229 return HeapRegion::block_size(addr); // Avoid virtual call
230 }
231
232 protected:
233 // The index of this region in the heap region sequence.
234 uint _hrm_index;
235
236 AllocationContext_t _allocation_context;
237
238 HeapRegionType _type;
239
240 // For a humongous region, region in which it starts.
241 HeapRegion* _humongous_start_region;
242
243 // True iff an attempt to evacuate an object in the region failed.
244 bool _evacuation_failed;
245
246 // A heap region may be a member one of a number of special subsets, each
247 // represented as linked lists through the field below. Currently, there
248 // is only one set:
249 // The collection set.
250 HeapRegion* _next_in_special_set;
251
252 // next region in the young "generation" region set
253 HeapRegion* _next_young_region;
254
255 // Next region whose cards need cleaning
256 HeapRegion* _next_dirty_cards_region;
257
258 // Fields used by the HeapRegionSetBase class and subclasses.
259 HeapRegion* _next;
260 HeapRegion* _prev;
261 #ifdef ASSERT
262 HeapRegionSetBase* _containing_set;
263 #endif // ASSERT
264
265 // We use concurrent marking to determine the amount of live data
266 // in each heap region.
267 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
268 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
269
270 // The calculated GC efficiency of the region.
271 double _gc_efficiency;
272
273 int _young_index_in_cset;
274 SurvRateGroup* _surv_rate_group;
275 int _age_index;
276
277 // The start of the unmarked area. The unmarked area extends from this
278 // word until the top and/or end of the region, and is the part
279 // of the region for which no marking was done, i.e. objects may
280 // have been allocated in this part since the last mark phase.
281 // "prev" is the top at the start of the last completed marking.
282 // "next" is the top at the start of the in-progress marking (if any.)
283 HeapWord* _prev_top_at_mark_start;
284 HeapWord* _next_top_at_mark_start;
285 // If a collection pause is in progress, this is the top at the start
286 // of that pause.
287
288 void init_top_at_mark_start() {
289 assert(_prev_marked_bytes == 0 &&
290 _next_marked_bytes == 0,
291 "Must be called after zero_marked_bytes.");
292 HeapWord* bot = bottom();
293 _prev_top_at_mark_start = bot;
294 _next_top_at_mark_start = bot;
295 }
296
297 // Cached attributes used in the collection set policy information
298
299 // The RSet length that was added to the total value
300 // for the collection set.
301 size_t _recorded_rs_length;
302
303 // The predicted elapsed time that was added to total value
304 // for the collection set.
305 double _predicted_elapsed_time_ms;
306
307 // The predicted number of bytes to copy that was added to
308 // the total value for the collection set.
309 size_t _predicted_bytes_to_copy;
310
311 public:
312 HeapRegion(uint hrm_index,
313 G1BlockOffsetSharedArray* sharedOffsetArray,
314 MemRegion mr);
315
316 // Initializing the HeapRegion not only resets the data structure, but also
317 // resets the BOT for that heap region.
318 // The default values for clear_space means that we will do the clearing if
319 // there's clearing to be done ourselves. We also always mangle the space.
320 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
321
322 static int LogOfHRGrainBytes;
323 static int LogOfHRGrainWords;
324
325 static size_t GrainBytes;
326 static size_t GrainWords;
327 static size_t CardsPerRegion;
328
329 static size_t align_up_to_region_byte_size(size_t sz) {
330 return (sz + (size_t) GrainBytes - 1) &
331 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
332 }
333
334 static size_t max_region_size();
335
336 // It sets up the heap region size (GrainBytes / GrainWords), as
337 // well as other related fields that are based on the heap region
338 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
339 // CardsPerRegion). All those fields are considered constant
340 // throughout the JVM's execution, therefore they should only be set
341 // up once during initialization time.
342 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
343
344 // All allocated blocks are occupied by objects in a HeapRegion
345 bool block_is_obj(const HeapWord* p) const;
346
347 // Returns the object size for all valid block starts
348 // and the amount of unallocated words if called on top()
349 size_t block_size(const HeapWord* p) const;
350
351 // Override for scan_and_forward support.
352 void prepare_for_compaction(CompactPoint* cp);
353
354 inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
355 inline HeapWord* allocate_no_bot_updates(size_t word_size);
356
357 // If this region is a member of a HeapRegionManager, the index in that
358 // sequence, otherwise -1.
359 uint hrm_index() const { return _hrm_index; }
360
361 // The number of bytes marked live in the region in the last marking phase.
362 size_t marked_bytes() { return _prev_marked_bytes; }
363 size_t live_bytes() {
364 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
365 }
366
367 // The number of bytes counted in the next marking.
368 size_t next_marked_bytes() { return _next_marked_bytes; }
369 // The number of bytes live wrt the next marking.
370 size_t next_live_bytes() {
371 return
372 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
373 }
374
375 // A lower bound on the amount of garbage bytes in the region.
376 size_t garbage_bytes() {
377 size_t used_at_mark_start_bytes =
378 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
379 assert(used_at_mark_start_bytes >= marked_bytes(),
380 "Can't mark more than we have.");
381 return used_at_mark_start_bytes - marked_bytes();
382 }
383
384 // Return the amount of bytes we'll reclaim if we collect this
385 // region. This includes not only the known garbage bytes in the
386 // region but also any unallocated space in it, i.e., [top, end),
387 // since it will also be reclaimed if we collect the region.
388 size_t reclaimable_bytes() {
389 size_t known_live_bytes = live_bytes();
390 assert(known_live_bytes <= capacity(), "sanity");
391 return capacity() - known_live_bytes;
392 }
393
394 // An upper bound on the number of live bytes in the region.
395 size_t max_live_bytes() { return used() - garbage_bytes(); }
396
397 void add_to_marked_bytes(size_t incr_bytes) {
398 _next_marked_bytes = _next_marked_bytes + incr_bytes;
399 assert(_next_marked_bytes <= used(), "invariant" );
400 }
401
402 void zero_marked_bytes() {
403 _prev_marked_bytes = _next_marked_bytes = 0;
404 }
405
406 const char* get_type_str() const { return _type.get_str(); }
407 const char* get_short_type_str() const { return _type.get_short_str(); }
408
409 bool is_free() const { return _type.is_free(); }
410
411 bool is_young() const { return _type.is_young(); }
412 bool is_eden() const { return _type.is_eden(); }
413 bool is_survivor() const { return _type.is_survivor(); }
414
415 bool is_humongous() const { return _type.is_humongous(); }
416 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
417 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
418
419 bool is_old() const { return _type.is_old(); }
420
421 // For a humongous region, region in which it starts.
422 HeapRegion* humongous_start_region() const {
423 return _humongous_start_region;
424 }
425
426 // Return the number of distinct regions that are covered by this region:
427 // 1 if the region is not humongous, >= 1 if the region is humongous.
428 uint region_num() const {
429 if (!is_humongous()) {
430 return 1U;
431 } else {
432 assert(is_starts_humongous(), "doesn't make sense on HC regions");
433 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
434 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
435 }
436 }
437
438 // Return the index + 1 of the last HC regions that's associated
439 // with this HS region.
440 uint last_hc_index() const {
441 assert(is_starts_humongous(), "don't call this otherwise");
442 return hrm_index() + region_num();
443 }
444
445 // Same as Space::is_in_reserved, but will use the original size of the region.
446 // The original size is different only for start humongous regions. They get
447 // their _end set up to be the end of the last continues region of the
448 // corresponding humongous object.
449 bool is_in_reserved_raw(const void* p) const {
450 return _bottom <= p && p < orig_end();
451 }
452
453 // Makes the current region be a "starts humongous" region, i.e.,
454 // the first region in a series of one or more contiguous regions
455 // that will contain a single "humongous" object. The two parameters
456 // are as follows:
457 //
458 // new_top : The new value of the top field of this region which
459 // points to the end of the humongous object that's being
460 // allocated. If there is more than one region in the series, top
461 // will lie beyond this region's original end field and on the last
462 // region in the series.
463 //
464 // new_end : The new value of the end field of this region which
465 // points to the end of the last region in the series. If there is
466 // one region in the series (namely: this one) end will be the same
467 // as the original end of this region.
468 //
469 // Updating top and end as described above makes this region look as
470 // if it spans the entire space taken up by all the regions in the
471 // series and an single allocation moved its top to new_top. This
472 // ensures that the space (capacity / allocated) taken up by all
473 // humongous regions can be calculated by just looking at the
474 // "starts humongous" regions and by ignoring the "continues
475 // humongous" regions.
476 void set_starts_humongous(HeapWord* new_top, HeapWord* new_end);
477
478 // Makes the current region be a "continues humongous'
479 // region. first_hr is the "start humongous" region of the series
480 // which this region will be part of.
481 void set_continues_humongous(HeapRegion* first_hr);
482
483 // Unsets the humongous-related fields on the region.
484 void clear_humongous();
485
486 // If the region has a remembered set, return a pointer to it.
487 HeapRegionRemSet* rem_set() const {
488 return _rem_set;
489 }
490
491 bool in_collection_set() const;
492
493 HeapRegion* next_in_collection_set() {
494 assert(in_collection_set(), "should only invoke on member of CS.");
495 assert(_next_in_special_set == NULL ||
496 _next_in_special_set->in_collection_set(),
497 "Malformed CS.");
498 return _next_in_special_set;
499 }
500 void set_next_in_collection_set(HeapRegion* r) {
501 assert(in_collection_set(), "should only invoke on member of CS.");
502 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
503 _next_in_special_set = r;
504 }
505
506 void set_allocation_context(AllocationContext_t context) {
507 _allocation_context = context;
508 }
509
510 AllocationContext_t allocation_context() const {
511 return _allocation_context;
512 }
513
514 // Methods used by the HeapRegionSetBase class and subclasses.
515
516 // Getter and setter for the next and prev fields used to link regions into
517 // linked lists.
518 HeapRegion* next() { return _next; }
519 HeapRegion* prev() { return _prev; }
520
521 void set_next(HeapRegion* next) { _next = next; }
522 void set_prev(HeapRegion* prev) { _prev = prev; }
523
524 // Every region added to a set is tagged with a reference to that
525 // set. This is used for doing consistency checking to make sure that
526 // the contents of a set are as they should be and it's only
527 // available in non-product builds.
528 #ifdef ASSERT
529 void set_containing_set(HeapRegionSetBase* containing_set) {
530 assert((containing_set == NULL && _containing_set != NULL) ||
531 (containing_set != NULL && _containing_set == NULL),
532 err_msg("containing_set: "PTR_FORMAT" "
533 "_containing_set: "PTR_FORMAT,
534 p2i(containing_set), p2i(_containing_set)));
535
536 _containing_set = containing_set;
537 }
538
539 HeapRegionSetBase* containing_set() { return _containing_set; }
540 #else // ASSERT
541 void set_containing_set(HeapRegionSetBase* containing_set) { }
542
543 // containing_set() is only used in asserts so there's no reason
544 // to provide a dummy version of it.
545 #endif // ASSERT
546
547 HeapRegion* get_next_young_region() { return _next_young_region; }
548 void set_next_young_region(HeapRegion* hr) {
549 _next_young_region = hr;
550 }
551
552 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
553 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
554 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
555 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
556
557 // For the start region of a humongous sequence, it's original end().
558 HeapWord* orig_end() const { return _bottom + GrainWords; }
559
560 // Reset HR stuff to default values.
561 void hr_clear(bool par, bool clear_space, bool locked = false);
562 void par_clear();
563
564 // Get the start of the unmarked area in this region.
565 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
566 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
567
568 // Note the start or end of marking. This tells the heap region
569 // that the collector is about to start or has finished (concurrently)
570 // marking the heap.
571
572 // Notify the region that concurrent marking is starting. Initialize
573 // all fields related to the next marking info.
574 inline void note_start_of_marking();
575
576 // Notify the region that concurrent marking has finished. Copy the
577 // (now finalized) next marking info fields into the prev marking
578 // info fields.
579 inline void note_end_of_marking();
580
581 // Notify the region that it will be used as to-space during a GC
582 // and we are about to start copying objects into it.
583 inline void note_start_of_copying(bool during_initial_mark);
584
585 // Notify the region that it ceases being to-space during a GC and
586 // we will not copy objects into it any more.
587 inline void note_end_of_copying(bool during_initial_mark);
588
589 // Notify the region that we are about to start processing
590 // self-forwarded objects during evac failure handling.
591 void note_self_forwarding_removal_start(bool during_initial_mark,
592 bool during_conc_mark);
593
594 // Notify the region that we have finished processing self-forwarded
595 // objects during evac failure handling.
596 void note_self_forwarding_removal_end(bool during_initial_mark,
597 bool during_conc_mark,
598 size_t marked_bytes);
599
600 // Returns "false" iff no object in the region was allocated when the
601 // last mark phase ended.
602 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
603
604 void reset_during_compaction() {
605 assert(is_starts_humongous(),
606 "should only be called for starts humongous regions");
607
608 zero_marked_bytes();
609 init_top_at_mark_start();
610 }
611
612 void calc_gc_efficiency(void);
613 double gc_efficiency() { return _gc_efficiency;}
614
615 int young_index_in_cset() const { return _young_index_in_cset; }
616 void set_young_index_in_cset(int index) {
617 assert( (index == -1) || is_young(), "pre-condition" );
618 _young_index_in_cset = index;
619 }
620
621 int age_in_surv_rate_group() {
622 assert( _surv_rate_group != NULL, "pre-condition" );
623 assert( _age_index > -1, "pre-condition" );
624 return _surv_rate_group->age_in_group(_age_index);
625 }
626
627 void record_surv_words_in_group(size_t words_survived) {
628 assert( _surv_rate_group != NULL, "pre-condition" );
629 assert( _age_index > -1, "pre-condition" );
630 int age_in_group = age_in_surv_rate_group();
631 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
632 }
633
634 int age_in_surv_rate_group_cond() {
635 if (_surv_rate_group != NULL)
636 return age_in_surv_rate_group();
637 else
638 return -1;
639 }
640
641 SurvRateGroup* surv_rate_group() {
642 return _surv_rate_group;
643 }
644
645 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
646 assert( surv_rate_group != NULL, "pre-condition" );
647 assert( _surv_rate_group == NULL, "pre-condition" );
648 assert( is_young(), "pre-condition" );
649
650 _surv_rate_group = surv_rate_group;
651 _age_index = surv_rate_group->next_age_index();
652 }
653
654 void uninstall_surv_rate_group() {
655 if (_surv_rate_group != NULL) {
656 assert( _age_index > -1, "pre-condition" );
657 assert( is_young(), "pre-condition" );
658
659 _surv_rate_group = NULL;
660 _age_index = -1;
661 } else {
662 assert( _age_index == -1, "pre-condition" );
663 }
664 }
665
666 void set_free() { _type.set_free(); }
667
668 void set_eden() { _type.set_eden(); }
669 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
670 void set_survivor() { _type.set_survivor(); }
671
672 void set_old() { _type.set_old(); }
673
674 // Determine if an object has been allocated since the last
675 // mark performed by the collector. This returns true iff the object
676 // is within the unmarked area of the region.
677 bool obj_allocated_since_prev_marking(oop obj) const {
678 return (HeapWord *) obj >= prev_top_at_mark_start();
679 }
680 bool obj_allocated_since_next_marking(oop obj) const {
681 return (HeapWord *) obj >= next_top_at_mark_start();
682 }
683
684 // Returns the "evacuation_failed" property of the region.
685 bool evacuation_failed() { return _evacuation_failed; }
686
687 // Sets the "evacuation_failed" property of the region.
688 void set_evacuation_failed(bool b) {
689 _evacuation_failed = b;
690
691 if (b) {
692 _next_marked_bytes = 0;
693 }
694 }
695
696 // Requires that "mr" be entirely within the region.
697 // Apply "cl->do_object" to all objects that intersect with "mr".
698 // If the iteration encounters an unparseable portion of the region,
699 // or if "cl->abort()" is true after a closure application,
700 // terminate the iteration and return the address of the start of the
701 // subregion that isn't done. (The two can be distinguished by querying
702 // "cl->abort()".) Return of "NULL" indicates that the iteration
703 // completed.
704 HeapWord*
705 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
706
707 // filter_young: if true and the region is a young region then we
708 // skip the iteration.
709 // card_ptr: if not NULL, and we decide that the card is not young
710 // and we iterate over it, we'll clean the card before we start the
711 // iteration.
712 HeapWord*
713 oops_on_card_seq_iterate_careful(MemRegion mr,
714 FilterOutOfRegionClosure* cl,
715 bool filter_young,
716 jbyte* card_ptr);
717
718 size_t recorded_rs_length() const { return _recorded_rs_length; }
719 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
720 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
721
722 void set_recorded_rs_length(size_t rs_length) {
723 _recorded_rs_length = rs_length;
724 }
725
726 void set_predicted_elapsed_time_ms(double ms) {
727 _predicted_elapsed_time_ms = ms;
728 }
729
730 void set_predicted_bytes_to_copy(size_t bytes) {
731 _predicted_bytes_to_copy = bytes;
732 }
733
734 virtual CompactibleSpace* next_compaction_space() const;
735
736 virtual void reset_after_compaction();
737
738 // Routines for managing a list of code roots (attached to the
739 // this region's RSet) that point into this heap region.
740 void add_strong_code_root(nmethod* nm);
741 void add_strong_code_root_locked(nmethod* nm);
742 void remove_strong_code_root(nmethod* nm);
743
744 // Applies blk->do_code_blob() to each of the entries in
745 // the strong code roots list for this region
746 void strong_code_roots_do(CodeBlobClosure* blk) const;
747
748 // Verify that the entries on the strong code root list for this
749 // region are live and include at least one pointer into this region.
750 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
751
752 void print() const;
753 void print_on(outputStream* st) const;
754
755 // vo == UsePrevMarking -> use "prev" marking information,
756 // vo == UseNextMarking -> use "next" marking information
757 // vo == UseMarkWord -> use the mark word in the object header
758 //
759 // NOTE: Only the "prev" marking information is guaranteed to be
760 // consistent most of the time, so most calls to this should use
761 // vo == UsePrevMarking.
762 // Currently, there is only one case where this is called with
763 // vo == UseNextMarking, which is to verify the "next" marking
764 // information at the end of remark.
765 // Currently there is only one place where this is called with
766 // vo == UseMarkWord, which is to verify the marking during a
767 // full GC.
768 void verify(VerifyOption vo, bool *failures) const;
769
770 // Override; it uses the "prev" marking information
771 virtual void verify() const;
772 };
773
774 // HeapRegionClosure is used for iterating over regions.
775 // Terminates the iteration when the "doHeapRegion" method returns "true".
776 class HeapRegionClosure : public StackObj {
777 friend class HeapRegionManager;
778 friend class G1CollectedHeap;
779
780 bool _complete;
781 void incomplete() { _complete = false; }
782
783 public:
784 HeapRegionClosure(): _complete(true) {}
785
786 // Typically called on each region until it returns true.
787 virtual bool doHeapRegion(HeapRegion* r) = 0;
788
789 // True after iteration if the closure was applied to all heap regions
790 // and returned "false" in all cases.
791 bool complete() { return _complete; }
792 };
793
794 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP