Fri, 29 Aug 2014 13:12:21 +0200
8048268: G1 Code Root Migration performs poorly
Summary: Replace G1CodeRootSet with a Hashtable based implementation, merge Code Root Migration phase into Code Root Scanning
Reviewed-by: jmasa, brutisso, tschatzl
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
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"
39 // A HeapRegion is the smallest piece of a G1CollectedHeap that
40 // can be collected independently.
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.
49 class HeapRegionRemSet;
50 class HeapRegionRemSetIterator;
51 class HeapRegion;
52 class HeapRegionSetBase;
53 class nmethod;
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())
61 // sentinel value for hrm_index
62 #define G1_NO_HRM_INDEX ((uint) -1)
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.
69 class HeapRegionDCTOC : public DirtyCardToOopClosure {
70 public:
71 // Specification of possible DirtyCardToOopClosure filtering.
72 enum FilterKind {
73 NoFilterKind,
74 IntoCSFilterKind,
75 OutOfRegionFilterKind
76 };
78 protected:
79 HeapRegion* _hr;
80 FilterKind _fk;
81 G1CollectedHeap* _g1;
83 // Walk the given memory region from bottom to (actual) top
84 // looking for objects and applying the oop closure (_cl) to
85 // them. The base implementation of this treats the area as
86 // blocks, where a block may or may not be an object. Sub-
87 // classes should override this to provide more accurate
88 // or possibly more efficient walking.
89 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
91 public:
92 HeapRegionDCTOC(G1CollectedHeap* g1,
93 HeapRegion* hr, ExtendedOopClosure* cl,
94 CardTableModRefBS::PrecisionStyle precision,
95 FilterKind fk);
96 };
98 // The complicating factor is that BlockOffsetTable diverged
99 // significantly, and we need functionality that is only in the G1 version.
100 // So I copied that code, which led to an alternate G1 version of
101 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
102 // be reconciled, then G1OffsetTableContigSpace could go away.
104 // The idea behind time stamps is the following. Doing a save_marks on
105 // all regions at every GC pause is time consuming (if I remember
106 // well, 10ms or so). So, we would like to do that only for regions
107 // that are GC alloc regions. To achieve this, we use time
108 // stamps. For every evacuation pause, G1CollectedHeap generates a
109 // unique time stamp (essentially a counter that gets
110 // incremented). Every time we want to call save_marks on a region,
111 // we set the saved_mark_word to top and also copy the current GC
112 // time stamp to the time stamp field of the space. Reading the
113 // saved_mark_word involves checking the time stamp of the
114 // region. If it is the same as the current GC time stamp, then we
115 // can safely read the saved_mark_word field, as it is valid. If the
116 // time stamp of the region is not the same as the current GC time
117 // stamp, then we instead read top, as the saved_mark_word field is
118 // invalid. Time stamps (on the regions and also on the
119 // G1CollectedHeap) are reset at every cleanup (we iterate over
120 // the regions anyway) and at the end of a Full GC. The current scheme
121 // that uses sequential unsigned ints will fail only if we have 4b
122 // evacuation pauses between two cleanups, which is _highly_ unlikely.
123 class G1OffsetTableContigSpace: public CompactibleSpace {
124 friend class VMStructs;
125 HeapWord* _top;
126 protected:
127 G1BlockOffsetArrayContigSpace _offsets;
128 Mutex _par_alloc_lock;
129 volatile unsigned _gc_time_stamp;
130 // When we need to retire an allocation region, while other threads
131 // are also concurrently trying to allocate into it, we typically
132 // allocate a dummy object at the end of the region to ensure that
133 // no more allocations can take place in it. However, sometimes we
134 // want to know where the end of the last "real" object we allocated
135 // into the region was and this is what this keeps track.
136 HeapWord* _pre_dummy_top;
138 public:
139 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
140 MemRegion mr);
142 void set_top(HeapWord* value) { _top = value; }
143 HeapWord* top() const { return _top; }
145 protected:
146 // Reset the G1OffsetTableContigSpace.
147 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
149 HeapWord** top_addr() { return &_top; }
150 // Allocation helpers (return NULL if full).
151 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
152 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
154 public:
155 void reset_after_compaction() { set_top(compaction_top()); }
157 size_t used() const { return byte_size(bottom(), top()); }
158 size_t free() const { return byte_size(top(), end()); }
159 bool is_free_block(const HeapWord* p) const { return p >= top(); }
161 MemRegion used_region() const { return MemRegion(bottom(), top()); }
163 void object_iterate(ObjectClosure* blk);
164 void safe_object_iterate(ObjectClosure* blk);
166 void set_bottom(HeapWord* value);
167 void set_end(HeapWord* value);
169 virtual HeapWord* saved_mark_word() const;
170 void record_top_and_timestamp();
171 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
172 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
174 // See the comment above in the declaration of _pre_dummy_top for an
175 // explanation of what it is.
176 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
177 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
178 _pre_dummy_top = pre_dummy_top;
179 }
180 HeapWord* pre_dummy_top() {
181 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
182 }
183 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
185 virtual void clear(bool mangle_space);
187 HeapWord* block_start(const void* p);
188 HeapWord* block_start_const(const void* p) const;
190 void prepare_for_compaction(CompactPoint* cp);
192 // Add offset table update.
193 virtual HeapWord* allocate(size_t word_size);
194 HeapWord* par_allocate(size_t word_size);
196 // MarkSweep support phase3
197 virtual HeapWord* initialize_threshold();
198 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
200 virtual void print() const;
202 void reset_bot() {
203 _offsets.reset_bot();
204 }
206 void update_bot_for_object(HeapWord* start, size_t word_size) {
207 _offsets.alloc_block(start, word_size);
208 }
210 void print_bot_on(outputStream* out) {
211 _offsets.print_on(out);
212 }
213 };
215 class HeapRegion: public G1OffsetTableContigSpace {
216 friend class VMStructs;
217 private:
219 // The remembered set for this region.
220 // (Might want to make this "inline" later, to avoid some alloc failure
221 // issues.)
222 HeapRegionRemSet* _rem_set;
224 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
226 protected:
227 // The index of this region in the heap region sequence.
228 uint _hrm_index;
230 AllocationContext_t _allocation_context;
232 HeapRegionType _type;
234 // For a humongous region, region in which it starts.
235 HeapRegion* _humongous_start_region;
236 // For the start region of a humongous sequence, it's original end().
237 HeapWord* _orig_end;
239 // True iff the region is in current collection_set.
240 bool _in_collection_set;
242 // True iff an attempt to evacuate an object in the region failed.
243 bool _evacuation_failed;
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;
251 // next region in the young "generation" region set
252 HeapRegion* _next_young_region;
254 // Next region whose cards need cleaning
255 HeapRegion* _next_dirty_cards_region;
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
264 // For parallel heapRegion traversal.
265 jint _claimed;
267 // We use concurrent marking to determine the amount of live data
268 // in each heap region.
269 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
270 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
272 // The calculated GC efficiency of the region.
273 double _gc_efficiency;
275 int _young_index_in_cset;
276 SurvRateGroup* _surv_rate_group;
277 int _age_index;
279 // The start of the unmarked area. The unmarked area extends from this
280 // word until the top and/or end of the region, and is the part
281 // of the region for which no marking was done, i.e. objects may
282 // have been allocated in this part since the last mark phase.
283 // "prev" is the top at the start of the last completed marking.
284 // "next" is the top at the start of the in-progress marking (if any.)
285 HeapWord* _prev_top_at_mark_start;
286 HeapWord* _next_top_at_mark_start;
287 // If a collection pause is in progress, this is the top at the start
288 // of that pause.
290 void init_top_at_mark_start() {
291 assert(_prev_marked_bytes == 0 &&
292 _next_marked_bytes == 0,
293 "Must be called after zero_marked_bytes.");
294 HeapWord* bot = bottom();
295 _prev_top_at_mark_start = bot;
296 _next_top_at_mark_start = bot;
297 }
299 // Cached attributes used in the collection set policy information
301 // The RSet length that was added to the total value
302 // for the collection set.
303 size_t _recorded_rs_length;
305 // The predicted elapsed time that was added to total value
306 // for the collection set.
307 double _predicted_elapsed_time_ms;
309 // The predicted number of bytes to copy that was added to
310 // the total value for the collection set.
311 size_t _predicted_bytes_to_copy;
313 public:
314 HeapRegion(uint hrm_index,
315 G1BlockOffsetSharedArray* sharedOffsetArray,
316 MemRegion mr);
318 // Initializing the HeapRegion not only resets the data structure, but also
319 // resets the BOT for that heap region.
320 // The default values for clear_space means that we will do the clearing if
321 // there's clearing to be done ourselves. We also always mangle the space.
322 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
324 static int LogOfHRGrainBytes;
325 static int LogOfHRGrainWords;
327 static size_t GrainBytes;
328 static size_t GrainWords;
329 static size_t CardsPerRegion;
331 static size_t align_up_to_region_byte_size(size_t sz) {
332 return (sz + (size_t) GrainBytes - 1) &
333 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
334 }
336 static size_t max_region_size();
338 // It sets up the heap region size (GrainBytes / GrainWords), as
339 // well as other related fields that are based on the heap region
340 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
341 // CardsPerRegion). All those fields are considered constant
342 // throughout the JVM's execution, therefore they should only be set
343 // up once during initialization time.
344 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
346 enum ClaimValues {
347 InitialClaimValue = 0,
348 FinalCountClaimValue = 1,
349 NoteEndClaimValue = 2,
350 ScrubRemSetClaimValue = 3,
351 ParVerifyClaimValue = 4,
352 RebuildRSClaimValue = 5,
353 ParEvacFailureClaimValue = 6,
354 AggregateCountClaimValue = 7,
355 VerifyCountClaimValue = 8,
356 ParMarkRootClaimValue = 9
357 };
359 // All allocated blocks are occupied by objects in a HeapRegion
360 bool block_is_obj(const HeapWord* p) const;
362 // Returns the object size for all valid block starts
363 // and the amount of unallocated words if called on top()
364 size_t block_size(const HeapWord* p) const;
366 inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
367 inline HeapWord* allocate_no_bot_updates(size_t word_size);
369 // If this region is a member of a HeapRegionManager, the index in that
370 // sequence, otherwise -1.
371 uint hrm_index() const { return _hrm_index; }
373 // The number of bytes marked live in the region in the last marking phase.
374 size_t marked_bytes() { return _prev_marked_bytes; }
375 size_t live_bytes() {
376 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
377 }
379 // The number of bytes counted in the next marking.
380 size_t next_marked_bytes() { return _next_marked_bytes; }
381 // The number of bytes live wrt the next marking.
382 size_t next_live_bytes() {
383 return
384 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
385 }
387 // A lower bound on the amount of garbage bytes in the region.
388 size_t garbage_bytes() {
389 size_t used_at_mark_start_bytes =
390 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
391 assert(used_at_mark_start_bytes >= marked_bytes(),
392 "Can't mark more than we have.");
393 return used_at_mark_start_bytes - marked_bytes();
394 }
396 // Return the amount of bytes we'll reclaim if we collect this
397 // region. This includes not only the known garbage bytes in the
398 // region but also any unallocated space in it, i.e., [top, end),
399 // since it will also be reclaimed if we collect the region.
400 size_t reclaimable_bytes() {
401 size_t known_live_bytes = live_bytes();
402 assert(known_live_bytes <= capacity(), "sanity");
403 return capacity() - known_live_bytes;
404 }
406 // An upper bound on the number of live bytes in the region.
407 size_t max_live_bytes() { return used() - garbage_bytes(); }
409 void add_to_marked_bytes(size_t incr_bytes) {
410 _next_marked_bytes = _next_marked_bytes + incr_bytes;
411 assert(_next_marked_bytes <= used(), "invariant" );
412 }
414 void zero_marked_bytes() {
415 _prev_marked_bytes = _next_marked_bytes = 0;
416 }
418 const char* get_type_str() const { return _type.get_str(); }
419 const char* get_short_type_str() const { return _type.get_short_str(); }
421 bool is_free() const { return _type.is_free(); }
423 bool is_young() const { return _type.is_young(); }
424 bool is_eden() const { return _type.is_eden(); }
425 bool is_survivor() const { return _type.is_survivor(); }
427 bool isHumongous() const { return _type.is_humongous(); }
428 bool startsHumongous() const { return _type.is_starts_humongous(); }
429 bool continuesHumongous() const { return _type.is_continues_humongous(); }
431 bool is_old() const { return _type.is_old(); }
433 // For a humongous region, region in which it starts.
434 HeapRegion* humongous_start_region() const {
435 return _humongous_start_region;
436 }
438 // Return the number of distinct regions that are covered by this region:
439 // 1 if the region is not humongous, >= 1 if the region is humongous.
440 uint region_num() const {
441 if (!isHumongous()) {
442 return 1U;
443 } else {
444 assert(startsHumongous(), "doesn't make sense on HC regions");
445 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
446 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
447 }
448 }
450 // Return the index + 1 of the last HC regions that's associated
451 // with this HS region.
452 uint last_hc_index() const {
453 assert(startsHumongous(), "don't call this otherwise");
454 return hrm_index() + region_num();
455 }
457 // Same as Space::is_in_reserved, but will use the original size of the region.
458 // The original size is different only for start humongous regions. They get
459 // their _end set up to be the end of the last continues region of the
460 // corresponding humongous object.
461 bool is_in_reserved_raw(const void* p) const {
462 return _bottom <= p && p < _orig_end;
463 }
465 // Makes the current region be a "starts humongous" region, i.e.,
466 // the first region in a series of one or more contiguous regions
467 // that will contain a single "humongous" object. The two parameters
468 // are as follows:
469 //
470 // new_top : The new value of the top field of this region which
471 // points to the end of the humongous object that's being
472 // allocated. If there is more than one region in the series, top
473 // will lie beyond this region's original end field and on the last
474 // region in the series.
475 //
476 // new_end : The new value of the end field of this region which
477 // points to the end of the last region in the series. If there is
478 // one region in the series (namely: this one) end will be the same
479 // as the original end of this region.
480 //
481 // Updating top and end as described above makes this region look as
482 // if it spans the entire space taken up by all the regions in the
483 // series and an single allocation moved its top to new_top. This
484 // ensures that the space (capacity / allocated) taken up by all
485 // humongous regions can be calculated by just looking at the
486 // "starts humongous" regions and by ignoring the "continues
487 // humongous" regions.
488 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
490 // Makes the current region be a "continues humongous'
491 // region. first_hr is the "start humongous" region of the series
492 // which this region will be part of.
493 void set_continuesHumongous(HeapRegion* first_hr);
495 // Unsets the humongous-related fields on the region.
496 void clear_humongous();
498 // If the region has a remembered set, return a pointer to it.
499 HeapRegionRemSet* rem_set() const {
500 return _rem_set;
501 }
503 // True iff the region is in current collection_set.
504 bool in_collection_set() const {
505 return _in_collection_set;
506 }
507 void set_in_collection_set(bool b) {
508 _in_collection_set = b;
509 }
510 HeapRegion* next_in_collection_set() {
511 assert(in_collection_set(), "should only invoke on member of CS.");
512 assert(_next_in_special_set == NULL ||
513 _next_in_special_set->in_collection_set(),
514 "Malformed CS.");
515 return _next_in_special_set;
516 }
517 void set_next_in_collection_set(HeapRegion* r) {
518 assert(in_collection_set(), "should only invoke on member of CS.");
519 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
520 _next_in_special_set = r;
521 }
523 void set_allocation_context(AllocationContext_t context) {
524 _allocation_context = context;
525 }
527 AllocationContext_t allocation_context() const {
528 return _allocation_context;
529 }
531 // Methods used by the HeapRegionSetBase class and subclasses.
533 // Getter and setter for the next and prev fields used to link regions into
534 // linked lists.
535 HeapRegion* next() { return _next; }
536 HeapRegion* prev() { return _prev; }
538 void set_next(HeapRegion* next) { _next = next; }
539 void set_prev(HeapRegion* prev) { _prev = prev; }
541 // Every region added to a set is tagged with a reference to that
542 // set. This is used for doing consistency checking to make sure that
543 // the contents of a set are as they should be and it's only
544 // available in non-product builds.
545 #ifdef ASSERT
546 void set_containing_set(HeapRegionSetBase* containing_set) {
547 assert((containing_set == NULL && _containing_set != NULL) ||
548 (containing_set != NULL && _containing_set == NULL),
549 err_msg("containing_set: "PTR_FORMAT" "
550 "_containing_set: "PTR_FORMAT,
551 p2i(containing_set), p2i(_containing_set)));
553 _containing_set = containing_set;
554 }
556 HeapRegionSetBase* containing_set() { return _containing_set; }
557 #else // ASSERT
558 void set_containing_set(HeapRegionSetBase* containing_set) { }
560 // containing_set() is only used in asserts so there's no reason
561 // to provide a dummy version of it.
562 #endif // ASSERT
564 HeapRegion* get_next_young_region() { return _next_young_region; }
565 void set_next_young_region(HeapRegion* hr) {
566 _next_young_region = hr;
567 }
569 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
570 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
571 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
572 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
574 HeapWord* orig_end() const { return _orig_end; }
576 // Reset HR stuff to default values.
577 void hr_clear(bool par, bool clear_space, bool locked = false);
578 void par_clear();
580 // Get the start of the unmarked area in this region.
581 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
582 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
584 // Note the start or end of marking. This tells the heap region
585 // that the collector is about to start or has finished (concurrently)
586 // marking the heap.
588 // Notify the region that concurrent marking is starting. Initialize
589 // all fields related to the next marking info.
590 inline void note_start_of_marking();
592 // Notify the region that concurrent marking has finished. Copy the
593 // (now finalized) next marking info fields into the prev marking
594 // info fields.
595 inline void note_end_of_marking();
597 // Notify the region that it will be used as to-space during a GC
598 // and we are about to start copying objects into it.
599 inline void note_start_of_copying(bool during_initial_mark);
601 // Notify the region that it ceases being to-space during a GC and
602 // we will not copy objects into it any more.
603 inline void note_end_of_copying(bool during_initial_mark);
605 // Notify the region that we are about to start processing
606 // self-forwarded objects during evac failure handling.
607 void note_self_forwarding_removal_start(bool during_initial_mark,
608 bool during_conc_mark);
610 // Notify the region that we have finished processing self-forwarded
611 // objects during evac failure handling.
612 void note_self_forwarding_removal_end(bool during_initial_mark,
613 bool during_conc_mark,
614 size_t marked_bytes);
616 // Returns "false" iff no object in the region was allocated when the
617 // last mark phase ended.
618 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
620 void reset_during_compaction() {
621 assert(isHumongous() && startsHumongous(),
622 "should only be called for starts humongous regions");
624 zero_marked_bytes();
625 init_top_at_mark_start();
626 }
628 void calc_gc_efficiency(void);
629 double gc_efficiency() { return _gc_efficiency;}
631 int young_index_in_cset() const { return _young_index_in_cset; }
632 void set_young_index_in_cset(int index) {
633 assert( (index == -1) || is_young(), "pre-condition" );
634 _young_index_in_cset = index;
635 }
637 int age_in_surv_rate_group() {
638 assert( _surv_rate_group != NULL, "pre-condition" );
639 assert( _age_index > -1, "pre-condition" );
640 return _surv_rate_group->age_in_group(_age_index);
641 }
643 void record_surv_words_in_group(size_t words_survived) {
644 assert( _surv_rate_group != NULL, "pre-condition" );
645 assert( _age_index > -1, "pre-condition" );
646 int age_in_group = age_in_surv_rate_group();
647 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
648 }
650 int age_in_surv_rate_group_cond() {
651 if (_surv_rate_group != NULL)
652 return age_in_surv_rate_group();
653 else
654 return -1;
655 }
657 SurvRateGroup* surv_rate_group() {
658 return _surv_rate_group;
659 }
661 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
662 assert( surv_rate_group != NULL, "pre-condition" );
663 assert( _surv_rate_group == NULL, "pre-condition" );
664 assert( is_young(), "pre-condition" );
666 _surv_rate_group = surv_rate_group;
667 _age_index = surv_rate_group->next_age_index();
668 }
670 void uninstall_surv_rate_group() {
671 if (_surv_rate_group != NULL) {
672 assert( _age_index > -1, "pre-condition" );
673 assert( is_young(), "pre-condition" );
675 _surv_rate_group = NULL;
676 _age_index = -1;
677 } else {
678 assert( _age_index == -1, "pre-condition" );
679 }
680 }
682 void set_free() { _type.set_free(); }
684 void set_eden() { _type.set_eden(); }
685 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
686 void set_survivor() { _type.set_survivor(); }
688 void set_old() { _type.set_old(); }
690 // Determine if an object has been allocated since the last
691 // mark performed by the collector. This returns true iff the object
692 // is within the unmarked area of the region.
693 bool obj_allocated_since_prev_marking(oop obj) const {
694 return (HeapWord *) obj >= prev_top_at_mark_start();
695 }
696 bool obj_allocated_since_next_marking(oop obj) const {
697 return (HeapWord *) obj >= next_top_at_mark_start();
698 }
700 // For parallel heapRegion traversal.
701 bool claimHeapRegion(int claimValue);
702 jint claim_value() { return _claimed; }
703 // Use this carefully: only when you're sure no one is claiming...
704 void set_claim_value(int claimValue) { _claimed = claimValue; }
706 // Returns the "evacuation_failed" property of the region.
707 bool evacuation_failed() { return _evacuation_failed; }
709 // Sets the "evacuation_failed" property of the region.
710 void set_evacuation_failed(bool b) {
711 _evacuation_failed = b;
713 if (b) {
714 _next_marked_bytes = 0;
715 }
716 }
718 // Requires that "mr" be entirely within the region.
719 // Apply "cl->do_object" to all objects that intersect with "mr".
720 // If the iteration encounters an unparseable portion of the region,
721 // or if "cl->abort()" is true after a closure application,
722 // terminate the iteration and return the address of the start of the
723 // subregion that isn't done. (The two can be distinguished by querying
724 // "cl->abort()".) Return of "NULL" indicates that the iteration
725 // completed.
726 HeapWord*
727 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
729 // filter_young: if true and the region is a young region then we
730 // skip the iteration.
731 // card_ptr: if not NULL, and we decide that the card is not young
732 // and we iterate over it, we'll clean the card before we start the
733 // iteration.
734 HeapWord*
735 oops_on_card_seq_iterate_careful(MemRegion mr,
736 FilterOutOfRegionClosure* cl,
737 bool filter_young,
738 jbyte* card_ptr);
740 // A version of block start that is guaranteed to find *some* block
741 // boundary at or before "p", but does not object iteration, and may
742 // therefore be used safely when the heap is unparseable.
743 HeapWord* block_start_careful(const void* p) const {
744 return _offsets.block_start_careful(p);
745 }
747 // Requires that "addr" is within the region. Returns the start of the
748 // first ("careful") block that starts at or after "addr", or else the
749 // "end" of the region if there is no such block.
750 HeapWord* next_block_start_careful(HeapWord* addr);
752 size_t recorded_rs_length() const { return _recorded_rs_length; }
753 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
754 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
756 void set_recorded_rs_length(size_t rs_length) {
757 _recorded_rs_length = rs_length;
758 }
760 void set_predicted_elapsed_time_ms(double ms) {
761 _predicted_elapsed_time_ms = ms;
762 }
764 void set_predicted_bytes_to_copy(size_t bytes) {
765 _predicted_bytes_to_copy = bytes;
766 }
768 virtual CompactibleSpace* next_compaction_space() const;
770 virtual void reset_after_compaction();
772 // Routines for managing a list of code roots (attached to the
773 // this region's RSet) that point into this heap region.
774 void add_strong_code_root(nmethod* nm);
775 void add_strong_code_root_locked(nmethod* nm);
776 void remove_strong_code_root(nmethod* nm);
778 // Applies blk->do_code_blob() to each of the entries in
779 // the strong code roots list for this region
780 void strong_code_roots_do(CodeBlobClosure* blk) const;
782 // Verify that the entries on the strong code root list for this
783 // region are live and include at least one pointer into this region.
784 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
786 void print() const;
787 void print_on(outputStream* st) const;
789 // vo == UsePrevMarking -> use "prev" marking information,
790 // vo == UseNextMarking -> use "next" marking information
791 // vo == UseMarkWord -> use the mark word in the object header
792 //
793 // NOTE: Only the "prev" marking information is guaranteed to be
794 // consistent most of the time, so most calls to this should use
795 // vo == UsePrevMarking.
796 // Currently, there is only one case where this is called with
797 // vo == UseNextMarking, which is to verify the "next" marking
798 // information at the end of remark.
799 // Currently there is only one place where this is called with
800 // vo == UseMarkWord, which is to verify the marking during a
801 // full GC.
802 void verify(VerifyOption vo, bool *failures) const;
804 // Override; it uses the "prev" marking information
805 virtual void verify() const;
806 };
808 // HeapRegionClosure is used for iterating over regions.
809 // Terminates the iteration when the "doHeapRegion" method returns "true".
810 class HeapRegionClosure : public StackObj {
811 friend class HeapRegionManager;
812 friend class G1CollectedHeap;
814 bool _complete;
815 void incomplete() { _complete = false; }
817 public:
818 HeapRegionClosure(): _complete(true) {}
820 // Typically called on each region until it returns true.
821 virtual bool doHeapRegion(HeapRegion* r) = 0;
823 // True after iteration if the closure was applied to all heap regions
824 // and returned "false" in all cases.
825 bool complete() { return _complete; }
826 };
828 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP