1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_VM_GC_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_G1_HEAPREGION_HPP
27
28 #include "gc/g1/g1AllocationContext.hpp"
29 #include "gc/g1/g1BlockOffsetTable.hpp"
30 #include "gc/g1/heapRegionType.hpp"
31 #include "gc/g1/survRateGroup.hpp"
32 #include "gc/shared/ageTable.hpp"
33 #include "gc/shared/spaceDecorator.hpp"
34 #include "utilities/macros.hpp"
35
36 // A HeapRegion is the smallest piece of a G1CollectedHeap that
37 // can be collected independently.
38
39 // NOTE: Although a HeapRegion is a Space, its
40 // Space::initDirtyCardClosure method must not be called.
41 // The problem is that the existence of this method breaks
42 // the independence of barrier sets from remembered sets.
43 // The solution is to remove this method from the definition
44 // of a Space.
45
46 class G1CollectedHeap;
47 class HeapRegionRemSet;
48 class HeapRegionRemSetIterator;
49 class HeapRegion;
50 class HeapRegionSetBase;
51 class nmethod;
52
53 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]"
54 #define HR_FORMAT_PARAMS(_hr_) \
55 (_hr_)->hrm_index(), \
56 (_hr_)->get_short_type_str(), \
57 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
58
59 // sentinel value for hrm_index
60 #define G1_NO_HRM_INDEX ((uint) -1)
61
62 // A dirty card to oop closure for heap regions. It
63 // knows how to get the G1 heap and how to use the bitmap
64 // in the concurrent marker used by G1 to filter remembered
65 // sets.
66
67 class HeapRegionDCTOC : public DirtyCardToOopClosure {
68 private:
69 HeapRegion* _hr;
70 G1ParPushHeapRSClosure* _rs_scan;
71 G1CollectedHeap* _g1;
72
73 // Walk the given memory region from bottom to (actual) top
74 // looking for objects and applying the oop closure (_cl) to
75 // them. The base implementation of this treats the area as
76 // blocks, where a block may or may not be an object. Sub-
77 // classes should override this to provide more accurate
78 // or possibly more efficient walking.
79 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
80
81 public:
82 HeapRegionDCTOC(G1CollectedHeap* g1,
83 HeapRegion* hr,
84 G1ParPushHeapRSClosure* cl,
85 CardTableModRefBS::PrecisionStyle precision);
86 };
87
88 // The complicating factor is that BlockOffsetTable diverged
89 // significantly, and we need functionality that is only in the G1 version.
90 // So I copied that code, which led to an alternate G1 version of
91 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
92 // be reconciled, then G1OffsetTableContigSpace could go away.
93
94 // The idea behind time stamps is the following. We want to keep track of
95 // the highest address where it's safe to scan objects for each region.
96 // This is only relevant for current GC alloc regions so we keep a time stamp
97 // per region to determine if the region has been allocated during the current
98 // GC or not. If the time stamp is current we report a scan_top value which
99 // was saved at the end of the previous GC for retained alloc regions and which is
100 // equal to the bottom for all other regions.
101 // There is a race between card scanners and allocating gc workers where we must ensure
102 // that card scanners do not read the memory allocated by the gc workers.
103 // In order to enforce that, we must not return a value of _top which is more recent than the
104 // time stamp. This is due to the fact that a region may become a gc alloc region at
105 // some point after we've read the timestamp value as being < the current time stamp.
106 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
107 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
108 // evacuation pauses between two cleanups, which is _highly_ unlikely.
109 class G1OffsetTableContigSpace: public CompactibleSpace {
110 friend class VMStructs;
111 HeapWord* volatile _top;
112 HeapWord* volatile _scan_top;
113 protected:
114 G1BlockOffsetArrayContigSpace _offsets;
115 Mutex _par_alloc_lock;
116 volatile unsigned _gc_time_stamp;
117 // When we need to retire an allocation region, while other threads
118 // are also concurrently trying to allocate into it, we typically
119 // allocate a dummy object at the end of the region to ensure that
120 // no more allocations can take place in it. However, sometimes we
121 // want to know where the end of the last "real" object we allocated
122 // into the region was and this is what this keeps track.
123 HeapWord* _pre_dummy_top;
124
125 public:
126 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
127 MemRegion mr);
128
129 void set_top(HeapWord* value) { _top = value; }
130 HeapWord* top() const { return _top; }
131
132 protected:
133 // Reset the G1OffsetTableContigSpace.
134 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
135
136 HeapWord* volatile* top_addr() { return &_top; }
137 // Try to allocate at least min_word_size and up to desired_size from this Space.
138 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
139 // space allocated.
140 // This version assumes that all allocation requests to this Space are properly
141 // synchronized.
142 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
143 // Try to allocate at least min_word_size and up to desired_size from this Space.
144 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
145 // space allocated.
146 // This version synchronizes with other calls to par_allocate_impl().
147 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
148
149 public:
150 void reset_after_compaction() { set_top(compaction_top()); }
151
152 size_t used() const { return byte_size(bottom(), top()); }
153 size_t free() const { return byte_size(top(), end()); }
154 bool is_free_block(const HeapWord* p) const { return p >= top(); }
155
156 MemRegion used_region() const { return MemRegion(bottom(), top()); }
157
158 void object_iterate(ObjectClosure* blk);
159 void safe_object_iterate(ObjectClosure* blk);
160
161 void set_bottom(HeapWord* value);
162 void set_end(HeapWord* value);
163
164 void mangle_unused_area() PRODUCT_RETURN;
165 void mangle_unused_area_complete() PRODUCT_RETURN;
166
167 HeapWord* scan_top() const;
168 void record_timestamp();
169 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
170 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
171 void record_retained_region();
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 // Allocation (return NULL if full). Assumes the caller has established
190 // mutually exclusive access to the space.
191 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
192 // Allocation (return NULL if full). Enforces mutual exclusion internally.
193 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
194
195 virtual HeapWord* allocate(size_t word_size);
196 virtual HeapWord* par_allocate(size_t word_size);
197
198 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
199
200 // MarkSweep support phase3
201 virtual HeapWord* initialize_threshold();
202 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
203
204 virtual void print() const;
205
206 void reset_bot() {
207 _offsets.reset_bot();
208 }
209
210 void print_bot_on(outputStream* out) {
211 _offsets.print_on(out);
212 }
213 };
214
215 class HeapRegion: public G1OffsetTableContigSpace {
216 friend class VMStructs;
217 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
218 template <typename SpaceType>
219 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
220 private:
221
222 // The remembered set for this region.
223 // (Might want to make this "inline" later, to avoid some alloc failure
224 // issues.)
225 HeapRegionRemSet* _rem_set;
226
227 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
228
229 // Auxiliary functions for scan_and_forward support.
230 // See comments for CompactibleSpace for more information.
231 inline HeapWord* scan_limit() const {
232 return top();
233 }
234
235 inline bool scanned_block_is_obj(const HeapWord* addr) const {
236 return true; // Always true, since scan_limit is top
237 }
238
239 inline size_t scanned_block_size(const HeapWord* addr) const {
240 return HeapRegion::block_size(addr); // Avoid virtual call
241 }
242
243 protected:
244 // The index of this region in the heap region sequence.
245 uint _hrm_index;
246
247 AllocationContext_t _allocation_context;
248
249 HeapRegionType _type;
250
251 // For a humongous region, region in which it starts.
252 HeapRegion* _humongous_start_region;
253
254 // True iff an attempt to evacuate an object in the region failed.
255 bool _evacuation_failed;
256
257 // A heap region may be a member one of a number of special subsets, each
258 // represented as linked lists through the field below. Currently, there
259 // is only one set:
260 // The collection set.
261 HeapRegion* _next_in_special_set;
262
263 // next region in the young "generation" region set
264 HeapRegion* _next_young_region;
265
266 // Next region whose cards need cleaning
267 HeapRegion* _next_dirty_cards_region;
268
269 // Fields used by the HeapRegionSetBase class and subclasses.
270 HeapRegion* _next;
271 HeapRegion* _prev;
272 #ifdef ASSERT
273 HeapRegionSetBase* _containing_set;
274 #endif // ASSERT
275
276 // We use concurrent marking to determine the amount of live data
277 // in each heap region.
278 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
279 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
280
281 // The calculated GC efficiency of the region.
282 double _gc_efficiency;
283
284 int _young_index_in_cset;
285 SurvRateGroup* _surv_rate_group;
286 int _age_index;
287
288 // The start of the unmarked area. The unmarked area extends from this
289 // word until the top and/or end of the region, and is the part
290 // of the region for which no marking was done, i.e. objects may
291 // have been allocated in this part since the last mark phase.
292 // "prev" is the top at the start of the last completed marking.
293 // "next" is the top at the start of the in-progress marking (if any.)
294 HeapWord* _prev_top_at_mark_start;
295 HeapWord* _next_top_at_mark_start;
296 // If a collection pause is in progress, this is the top at the start
297 // of that pause.
298
299 void init_top_at_mark_start() {
300 assert(_prev_marked_bytes == 0 &&
301 _next_marked_bytes == 0,
302 "Must be called after zero_marked_bytes.");
303 HeapWord* bot = bottom();
304 _prev_top_at_mark_start = bot;
305 _next_top_at_mark_start = bot;
306 }
307
308 // Cached attributes used in the collection set policy information
309
310 // The RSet length that was added to the total value
311 // for the collection set.
312 size_t _recorded_rs_length;
313
314 // The predicted elapsed time that was added to total value
315 // for the collection set.
316 double _predicted_elapsed_time_ms;
317
318 // The predicted number of bytes to copy that was added to
319 // the total value for the collection set.
320 size_t _predicted_bytes_to_copy;
321
322 public:
323 HeapRegion(uint hrm_index,
324 G1BlockOffsetSharedArray* sharedOffsetArray,
325 MemRegion mr);
326
327 // Initializing the HeapRegion not only resets the data structure, but also
328 // resets the BOT for that heap region.
329 // The default values for clear_space means that we will do the clearing if
330 // there's clearing to be done ourselves. We also always mangle the space.
331 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
332
333 static int LogOfHRGrainBytes;
334 static int LogOfHRGrainWords;
335
336 static size_t GrainBytes;
337 static size_t GrainWords;
338 static size_t CardsPerRegion;
339
340 static size_t align_up_to_region_byte_size(size_t sz) {
341 return (sz + (size_t) GrainBytes - 1) &
342 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
343 }
344
345 static size_t max_region_size();
346 static size_t min_region_size_in_words();
347
348 // It sets up the heap region size (GrainBytes / GrainWords), as
349 // well as other related fields that are based on the heap region
350 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
351 // CardsPerRegion). All those fields are considered constant
352 // throughout the JVM's execution, therefore they should only be set
353 // up once during initialization time.
354 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
355
356 // All allocated blocks are occupied by objects in a HeapRegion
357 bool block_is_obj(const HeapWord* p) const;
358
359 // Returns the object size for all valid block starts
360 // and the amount of unallocated words if called on top()
361 size_t block_size(const HeapWord* p) const;
362
363 // Override for scan_and_forward support.
364 void prepare_for_compaction(CompactPoint* cp);
365
366 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size);
367 inline HeapWord* allocate_no_bot_updates(size_t word_size);
368 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size);
369
370 // If this region is a member of a HeapRegionManager, the index in that
371 // sequence, otherwise -1.
372 uint hrm_index() const { return _hrm_index; }
373
374 // The number of bytes marked live in the region in the last marking phase.
375 size_t marked_bytes() { return _prev_marked_bytes; }
376 size_t live_bytes() {
377 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
378 }
379
380 // The number of bytes counted in the next marking.
381 size_t next_marked_bytes() { return _next_marked_bytes; }
382 // The number of bytes live wrt the next marking.
383 size_t next_live_bytes() {
384 return
385 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
386 }
387
388 // A lower bound on the amount of garbage bytes in the region.
389 size_t garbage_bytes() {
390 size_t used_at_mark_start_bytes =
391 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
392 assert(used_at_mark_start_bytes >= marked_bytes(),
393 "Can't mark more than we have.");
394 return used_at_mark_start_bytes - marked_bytes();
395 }
396
397 // Return the amount of bytes we'll reclaim if we collect this
398 // region. This includes not only the known garbage bytes in the
399 // region but also any unallocated space in it, i.e., [top, end),
400 // since it will also be reclaimed if we collect the region.
401 size_t reclaimable_bytes() {
402 size_t known_live_bytes = live_bytes();
403 assert(known_live_bytes <= capacity(), "sanity");
404 return capacity() - known_live_bytes;
405 }
406
407 // An upper bound on the number of live bytes in the region.
408 size_t max_live_bytes() { return used() - garbage_bytes(); }
409
410 void add_to_marked_bytes(size_t incr_bytes) {
411 _next_marked_bytes = _next_marked_bytes + incr_bytes;
412 assert(_next_marked_bytes <= used(), "invariant" );
413 }
414
415 void zero_marked_bytes() {
416 _prev_marked_bytes = _next_marked_bytes = 0;
417 }
418
419 const char* get_type_str() const { return _type.get_str(); }
420 const char* get_short_type_str() const { return _type.get_short_str(); }
421
422 bool is_free() const { return _type.is_free(); }
423
424 bool is_young() const { return _type.is_young(); }
425 bool is_eden() const { return _type.is_eden(); }
426 bool is_survivor() const { return _type.is_survivor(); }
427
428 bool is_humongous() const { return _type.is_humongous(); }
429 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
430 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
431
432 bool is_old() const { return _type.is_old(); }
433
434 // A pinned region contains objects which are not moved by garbage collections.
435 // Humongous regions and archive regions are pinned.
436 bool is_pinned() const { return _type.is_pinned(); }
437
438 // An archive region is a pinned region, also tagged as old, which
439 // should not be marked during mark/sweep. This allows the address
440 // space to be shared by JVM instances.
441 bool is_archive() const { return _type.is_archive(); }
442
443 // For a humongous region, region in which it starts.
444 HeapRegion* humongous_start_region() const {
445 return _humongous_start_region;
446 }
447
448 // Return the number of distinct regions that are covered by this region:
449 // 1 if the region is not humongous, >= 1 if the region is humongous.
450 uint region_num() const {
451 if (!is_humongous()) {
452 return 1U;
453 } else {
454 assert(is_starts_humongous(), "doesn't make sense on HC regions");
455 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
456 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
457 }
458 }
459
460 // Return the index + 1 of the last HC regions that's associated
461 // with this HS region.
462 uint last_hc_index() const {
463 assert(is_starts_humongous(), "don't call this otherwise");
464 return hrm_index() + region_num();
465 }
466
467 // Same as Space::is_in_reserved, but will use the original size of the region.
468 // The original size is different only for start humongous regions. They get
469 // their _end set up to be the end of the last continues region of the
470 // corresponding humongous object.
471 bool is_in_reserved_raw(const void* p) const {
472 return _bottom <= p && p < orig_end();
473 }
474
475 // Makes the current region be a "starts humongous" region, i.e.,
476 // the first region in a series of one or more contiguous regions
477 // that will contain a single "humongous" object. The two parameters
478 // are as follows:
479 //
480 // new_top : The new value of the top field of this region which
481 // points to the end of the humongous object that's being
482 // allocated. If there is more than one region in the series, top
483 // will lie beyond this region's original end field and on the last
484 // region in the series.
485 //
486 // new_end : The new value of the end field of this region which
487 // points to the end of the last region in the series. If there is
488 // one region in the series (namely: this one) end will be the same
489 // as the original end of this region.
490 //
491 // Updating top and end as described above makes this region look as
492 // if it spans the entire space taken up by all the regions in the
493 // series and an single allocation moved its top to new_top. This
494 // ensures that the space (capacity / allocated) taken up by all
495 // humongous regions can be calculated by just looking at the
496 // "starts humongous" regions and by ignoring the "continues
497 // humongous" regions.
498 void set_starts_humongous(HeapWord* new_top, HeapWord* new_end);
499
500 // Makes the current region be a "continues humongous'
501 // region. first_hr is the "start humongous" region of the series
502 // which this region will be part of.
503 void set_continues_humongous(HeapRegion* first_hr);
504
505 // Unsets the humongous-related fields on the region.
506 void clear_humongous();
507
508 // If the region has a remembered set, return a pointer to it.
509 HeapRegionRemSet* rem_set() const {
510 return _rem_set;
511 }
512
513 inline bool in_collection_set() const;
514
515 inline HeapRegion* next_in_collection_set() const;
516 inline void set_next_in_collection_set(HeapRegion* r);
517
518 void set_allocation_context(AllocationContext_t context) {
519 _allocation_context = context;
520 }
521
522 AllocationContext_t allocation_context() const {
523 return _allocation_context;
524 }
525
526 // Methods used by the HeapRegionSetBase class and subclasses.
527
528 // Getter and setter for the next and prev fields used to link regions into
529 // linked lists.
530 HeapRegion* next() { return _next; }
531 HeapRegion* prev() { return _prev; }
532
533 void set_next(HeapRegion* next) { _next = next; }
534 void set_prev(HeapRegion* prev) { _prev = prev; }
535
536 // Every region added to a set is tagged with a reference to that
537 // set. This is used for doing consistency checking to make sure that
538 // the contents of a set are as they should be and it's only
539 // available in non-product builds.
540 #ifdef ASSERT
541 void set_containing_set(HeapRegionSetBase* containing_set) {
542 assert((containing_set == NULL && _containing_set != NULL) ||
543 (containing_set != NULL && _containing_set == NULL),
544 "containing_set: " PTR_FORMAT " "
545 "_containing_set: " PTR_FORMAT,
546 p2i(containing_set), p2i(_containing_set));
547
548 _containing_set = containing_set;
549 }
550
551 HeapRegionSetBase* containing_set() { return _containing_set; }
552 #else // ASSERT
553 void set_containing_set(HeapRegionSetBase* containing_set) { }
554
555 // containing_set() is only used in asserts so there's no reason
556 // to provide a dummy version of it.
557 #endif // ASSERT
558
559 HeapRegion* get_next_young_region() { return _next_young_region; }
560 void set_next_young_region(HeapRegion* hr) {
561 _next_young_region = hr;
562 }
563
564 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
565 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
566 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
567 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
568
569 // For the start region of a humongous sequence, it's original end().
570 HeapWord* orig_end() const { return _bottom + GrainWords; }
571
572 // Reset HR stuff to default values.
573 void hr_clear(bool par, bool clear_space, bool locked = false);
574 void par_clear();
575
576 // Get the start of the unmarked area in this region.
577 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
578 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
579
580 // Note the start or end of marking. This tells the heap region
581 // that the collector is about to start or has finished (concurrently)
582 // marking the heap.
583
584 // Notify the region that concurrent marking is starting. Initialize
585 // all fields related to the next marking info.
586 inline void note_start_of_marking();
587
588 // Notify the region that concurrent marking has finished. Copy the
589 // (now finalized) next marking info fields into the prev marking
590 // info fields.
591 inline void note_end_of_marking();
592
593 // Notify the region that it will be used as to-space during a GC
594 // and we are about to start copying objects into it.
595 inline void note_start_of_copying(bool during_initial_mark);
596
597 // Notify the region that it ceases being to-space during a GC and
598 // we will not copy objects into it any more.
599 inline void note_end_of_copying(bool during_initial_mark);
600
601 // Notify the region that we are about to start processing
602 // self-forwarded objects during evac failure handling.
603 void note_self_forwarding_removal_start(bool during_initial_mark,
604 bool during_conc_mark);
605
606 // Notify the region that we have finished processing self-forwarded
607 // objects during evac failure handling.
608 void note_self_forwarding_removal_end(bool during_initial_mark,
609 bool during_conc_mark,
610 size_t marked_bytes);
611
612 // Returns "false" iff no object in the region was allocated when the
613 // last mark phase ended.
614 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
615
616 void reset_during_compaction() {
617 assert(is_starts_humongous(),
618 "should only be called for starts humongous regions");
619
620 zero_marked_bytes();
621 init_top_at_mark_start();
622 }
623
624 void calc_gc_efficiency(void);
625 double gc_efficiency() { return _gc_efficiency;}
626
627 int young_index_in_cset() const { return _young_index_in_cset; }
628 void set_young_index_in_cset(int index) {
629 assert( (index == -1) || is_young(), "pre-condition" );
630 _young_index_in_cset = index;
631 }
632
633 int age_in_surv_rate_group() {
634 assert( _surv_rate_group != NULL, "pre-condition" );
635 assert( _age_index > -1, "pre-condition" );
636 return _surv_rate_group->age_in_group(_age_index);
637 }
638
639 void record_surv_words_in_group(size_t words_survived) {
640 assert( _surv_rate_group != NULL, "pre-condition" );
641 assert( _age_index > -1, "pre-condition" );
642 int age_in_group = age_in_surv_rate_group();
643 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
644 }
645
646 int age_in_surv_rate_group_cond() {
647 if (_surv_rate_group != NULL)
648 return age_in_surv_rate_group();
649 else
650 return -1;
651 }
652
653 SurvRateGroup* surv_rate_group() {
654 return _surv_rate_group;
655 }
656
657 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
658 assert( surv_rate_group != NULL, "pre-condition" );
659 assert( _surv_rate_group == NULL, "pre-condition" );
660 assert( is_young(), "pre-condition" );
661
662 _surv_rate_group = surv_rate_group;
663 _age_index = surv_rate_group->next_age_index();
664 }
665
666 void uninstall_surv_rate_group() {
667 if (_surv_rate_group != NULL) {
668 assert( _age_index > -1, "pre-condition" );
669 assert( is_young(), "pre-condition" );
670
671 _surv_rate_group = NULL;
672 _age_index = -1;
673 } else {
674 assert( _age_index == -1, "pre-condition" );
675 }
676 }
677
678 void set_free() { _type.set_free(); }
679
680 void set_eden() { _type.set_eden(); }
681 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
682 void set_survivor() { _type.set_survivor(); }
683
684 void set_old() { _type.set_old(); }
685
686 void set_archive() { _type.set_archive(); }
687
688 // Determine if an object has been allocated since the last
689 // mark performed by the collector. This returns true iff the object
690 // is within the unmarked area of the region.
691 bool obj_allocated_since_prev_marking(oop obj) const {
692 return (HeapWord *) obj >= prev_top_at_mark_start();
693 }
694 bool obj_allocated_since_next_marking(oop obj) const {
695 return (HeapWord *) obj >= next_top_at_mark_start();
696 }
697
698 // Returns the "evacuation_failed" property of the region.
699 bool evacuation_failed() { return _evacuation_failed; }
700
701 // Sets the "evacuation_failed" property of the region.
702 void set_evacuation_failed(bool b) {
703 _evacuation_failed = b;
704
705 if (b) {
706 _next_marked_bytes = 0;
707 }
708 }
709
710 // Requires that "mr" be entirely within the region.
711 // Apply "cl->do_object" to all objects that intersect with "mr".
712 // If the iteration encounters an unparseable portion of the region,
713 // or if "cl->abort()" is true after a closure application,
714 // terminate the iteration and return the address of the start of the
715 // subregion that isn't done. (The two can be distinguished by querying
716 // "cl->abort()".) Return of "NULL" indicates that the iteration
717 // completed.
718 HeapWord*
719 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
720
721 // filter_young: if true and the region is a young region then we
722 // skip the iteration.
723 // card_ptr: if not NULL, and we decide that the card is not young
724 // and we iterate over it, we'll clean the card before we start the
725 // iteration.
726 HeapWord*
727 oops_on_card_seq_iterate_careful(MemRegion mr,
728 FilterOutOfRegionClosure* cl,
729 bool filter_young,
730 jbyte* card_ptr);
731
732 size_t recorded_rs_length() const { return _recorded_rs_length; }
733 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
734 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
735
736 void set_recorded_rs_length(size_t rs_length) {
737 _recorded_rs_length = rs_length;
738 }
739
740 void set_predicted_elapsed_time_ms(double ms) {
741 _predicted_elapsed_time_ms = ms;
742 }
743
744 void set_predicted_bytes_to_copy(size_t bytes) {
745 _predicted_bytes_to_copy = bytes;
746 }
747
748 virtual CompactibleSpace* next_compaction_space() const;
749
750 virtual void reset_after_compaction();
751
752 // Routines for managing a list of code roots (attached to the
753 // this region's RSet) that point into this heap region.
754 void add_strong_code_root(nmethod* nm);
755 void add_strong_code_root_locked(nmethod* nm);
756 void remove_strong_code_root(nmethod* nm);
757
758 // Applies blk->do_code_blob() to each of the entries in
759 // the strong code roots list for this region
760 void strong_code_roots_do(CodeBlobClosure* blk) const;
761
762 // Verify that the entries on the strong code root list for this
763 // region are live and include at least one pointer into this region.
764 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
765
766 void print() const;
767 void print_on(outputStream* st) const;
768
769 // vo == UsePrevMarking -> use "prev" marking information,
770 // vo == UseNextMarking -> use "next" marking information
771 // vo == UseMarkWord -> use the mark word in the object header
772 //
773 // NOTE: Only the "prev" marking information is guaranteed to be
774 // consistent most of the time, so most calls to this should use
775 // vo == UsePrevMarking.
776 // Currently, there is only one case where this is called with
777 // vo == UseNextMarking, which is to verify the "next" marking
778 // information at the end of remark.
779 // Currently there is only one place where this is called with
780 // vo == UseMarkWord, which is to verify the marking during a
781 // full GC.
782 void verify(VerifyOption vo, bool *failures) const;
783
784 // Override; it uses the "prev" marking information
785 virtual void verify() const;
786 };
787
788 // HeapRegionClosure is used for iterating over regions.
789 // Terminates the iteration when the "doHeapRegion" method returns "true".
790 class HeapRegionClosure : public StackObj {
791 friend class HeapRegionManager;
792 friend class G1CollectedHeap;
793
794 bool _complete;
795 void incomplete() { _complete = false; }
796
797 public:
798 HeapRegionClosure(): _complete(true) {}
799
800 // Typically called on each region until it returns true.
801 virtual bool doHeapRegion(HeapRegion* r) = 0;
802
803 // True after iteration if the closure was applied to all heap regions
804 // and returned "false" in all cases.
805 bool complete() { return _complete; }
806 };
807
808 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP