Tue, 01 Mar 2011 14:56:48 -0800
6627983: G1: Bad oop deference during marking
Summary: Bulk zeroing reduction didn't work with G1, because arraycopy would call pre-barriers on uninitialized oops. The solution is to have version of arraycopy stubs that don't have pre-barriers. Also refactored arraycopy stubs generation on SPARC to be more readable and reduced the number of stubs necessary in some cases.
Reviewed-by: jrose, kvn, never
1 /*
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
28 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
29 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
30 #include "gc_implementation/g1/survRateGroup.hpp"
31 #include "gc_implementation/shared/ageTable.hpp"
32 #include "gc_implementation/shared/spaceDecorator.hpp"
33 #include "memory/space.inline.hpp"
34 #include "memory/watermark.hpp"
36 #ifndef SERIALGC
38 // A HeapRegion is the smallest piece of a G1CollectedHeap that
39 // can be collected independently.
41 // NOTE: Although a HeapRegion is a Space, its
42 // Space::initDirtyCardClosure method must not be called.
43 // The problem is that the existence of this method breaks
44 // the independence of barrier sets from remembered sets.
45 // The solution is to remove this method from the definition
46 // of a Space.
48 class CompactibleSpace;
49 class ContiguousSpace;
50 class HeapRegionRemSet;
51 class HeapRegionRemSetIterator;
52 class HeapRegion;
53 class HeapRegionSetBase;
55 #define HR_FORMAT "%d:["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
56 #define HR_FORMAT_PARAMS(__hr) (__hr)->hrs_index(), (__hr)->bottom(), \
57 (__hr)->top(), (__hr)->end()
59 // A dirty card to oop closure for heap regions. It
60 // knows how to get the G1 heap and how to use the bitmap
61 // in the concurrent marker used by G1 to filter remembered
62 // sets.
64 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
65 public:
66 // Specification of possible DirtyCardToOopClosure filtering.
67 enum FilterKind {
68 NoFilterKind,
69 IntoCSFilterKind,
70 OutOfRegionFilterKind
71 };
73 protected:
74 HeapRegion* _hr;
75 FilterKind _fk;
76 G1CollectedHeap* _g1;
78 void walk_mem_region_with_cl(MemRegion mr,
79 HeapWord* bottom, HeapWord* top,
80 OopClosure* cl);
82 // We don't specialize this for FilteringClosure; filtering is handled by
83 // the "FilterKind" mechanism. But we provide this to avoid a compiler
84 // warning.
85 void walk_mem_region_with_cl(MemRegion mr,
86 HeapWord* bottom, HeapWord* top,
87 FilteringClosure* cl) {
88 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
89 (OopClosure*)cl);
90 }
92 // Get the actual top of the area on which the closure will
93 // operate, given where the top is assumed to be (the end of the
94 // memory region passed to do_MemRegion) and where the object
95 // at the top is assumed to start. For example, an object may
96 // start at the top but actually extend past the assumed top,
97 // in which case the top becomes the end of the object.
98 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
99 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
100 }
102 // Walk the given memory region from bottom to (actual) top
103 // looking for objects and applying the oop closure (_cl) to
104 // them. The base implementation of this treats the area as
105 // blocks, where a block may or may not be an object. Sub-
106 // classes should override this to provide more accurate
107 // or possibly more efficient walking.
108 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) {
109 Filtering_DCTOC::walk_mem_region(mr, bottom, top);
110 }
112 public:
113 HeapRegionDCTOC(G1CollectedHeap* g1,
114 HeapRegion* hr, OopClosure* cl,
115 CardTableModRefBS::PrecisionStyle precision,
116 FilterKind fk);
117 };
120 // The complicating factor is that BlockOffsetTable diverged
121 // significantly, and we need functionality that is only in the G1 version.
122 // So I copied that code, which led to an alternate G1 version of
123 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
124 // be reconciled, then G1OffsetTableContigSpace could go away.
126 // The idea behind time stamps is the following. Doing a save_marks on
127 // all regions at every GC pause is time consuming (if I remember
128 // well, 10ms or so). So, we would like to do that only for regions
129 // that are GC alloc regions. To achieve this, we use time
130 // stamps. For every evacuation pause, G1CollectedHeap generates a
131 // unique time stamp (essentially a counter that gets
132 // incremented). Every time we want to call save_marks on a region,
133 // we set the saved_mark_word to top and also copy the current GC
134 // time stamp to the time stamp field of the space. Reading the
135 // saved_mark_word involves checking the time stamp of the
136 // region. If it is the same as the current GC time stamp, then we
137 // can safely read the saved_mark_word field, as it is valid. If the
138 // time stamp of the region is not the same as the current GC time
139 // stamp, then we instead read top, as the saved_mark_word field is
140 // invalid. Time stamps (on the regions and also on the
141 // G1CollectedHeap) are reset at every cleanup (we iterate over
142 // the regions anyway) and at the end of a Full GC. The current scheme
143 // that uses sequential unsigned ints will fail only if we have 4b
144 // evacuation pauses between two cleanups, which is _highly_ unlikely.
146 class G1OffsetTableContigSpace: public ContiguousSpace {
147 friend class VMStructs;
148 protected:
149 G1BlockOffsetArrayContigSpace _offsets;
150 Mutex _par_alloc_lock;
151 volatile unsigned _gc_time_stamp;
153 public:
154 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be
155 // assumed to contain zeros.
156 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
157 MemRegion mr, bool is_zeroed = false);
159 void set_bottom(HeapWord* value);
160 void set_end(HeapWord* value);
162 virtual HeapWord* saved_mark_word() const;
163 virtual void set_saved_mark();
164 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
166 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
167 virtual void clear(bool mangle_space);
169 HeapWord* block_start(const void* p);
170 HeapWord* block_start_const(const void* p) const;
172 // Add offset table update.
173 virtual HeapWord* allocate(size_t word_size);
174 HeapWord* par_allocate(size_t word_size);
176 // MarkSweep support phase3
177 virtual HeapWord* initialize_threshold();
178 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
180 virtual void print() const;
182 void reset_bot() {
183 _offsets.zero_bottom_entry();
184 _offsets.initialize_threshold();
185 }
187 void update_bot_for_object(HeapWord* start, size_t word_size) {
188 _offsets.alloc_block(start, word_size);
189 }
191 void print_bot_on(outputStream* out) {
192 _offsets.print_on(out);
193 }
194 };
196 class HeapRegion: public G1OffsetTableContigSpace {
197 friend class VMStructs;
198 private:
200 enum HumongousType {
201 NotHumongous = 0,
202 StartsHumongous,
203 ContinuesHumongous
204 };
206 // The next filter kind that should be used for a "new_dcto_cl" call with
207 // the "traditional" signature.
208 HeapRegionDCTOC::FilterKind _next_fk;
210 // Requires that the region "mr" be dense with objects, and begin and end
211 // with an object.
212 void oops_in_mr_iterate(MemRegion mr, OopClosure* cl);
214 // The remembered set for this region.
215 // (Might want to make this "inline" later, to avoid some alloc failure
216 // issues.)
217 HeapRegionRemSet* _rem_set;
219 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
221 protected:
222 // If this region is a member of a HeapRegionSeq, the index in that
223 // sequence, otherwise -1.
224 int _hrs_index;
226 HumongousType _humongous_type;
227 // For a humongous region, region in which it starts.
228 HeapRegion* _humongous_start_region;
229 // For the start region of a humongous sequence, it's original end().
230 HeapWord* _orig_end;
232 // True iff the region is in current collection_set.
233 bool _in_collection_set;
235 // Is this or has it been an allocation region in the current collection
236 // pause.
237 bool _is_gc_alloc_region;
239 // True iff an attempt to evacuate an object in the region failed.
240 bool _evacuation_failed;
242 // A heap region may be a member one of a number of special subsets, each
243 // represented as linked lists through the field below. Currently, these
244 // sets include:
245 // The collection set.
246 // The set of allocation regions used in a collection pause.
247 // Spaces that may contain gray objects.
248 HeapRegion* _next_in_special_set;
250 // next region in the young "generation" region set
251 HeapRegion* _next_young_region;
253 // Next region whose cards need cleaning
254 HeapRegion* _next_dirty_cards_region;
256 // Fields used by the HeapRegionSetBase class and subclasses.
257 HeapRegion* _next;
258 #ifdef ASSERT
259 HeapRegionSetBase* _containing_set;
260 #endif // ASSERT
261 bool _pending_removal;
263 // For parallel heapRegion traversal.
264 jint _claimed;
266 // We use concurrent marking to determine the amount of live data
267 // in each heap region.
268 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
269 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
271 // See "sort_index" method. -1 means is not in the array.
272 int _sort_index;
274 // <PREDICTION>
275 double _gc_efficiency;
276 // </PREDICTION>
278 enum YoungType {
279 NotYoung, // a region is not young
280 Young, // a region is young
281 Survivor // a region is young and it contains
282 // survivor
283 };
285 volatile YoungType _young_type;
286 int _young_index_in_cset;
287 SurvRateGroup* _surv_rate_group;
288 int _age_index;
290 // The start of the unmarked area. The unmarked area extends from this
291 // word until the top and/or end of the region, and is the part
292 // of the region for which no marking was done, i.e. objects may
293 // have been allocated in this part since the last mark phase.
294 // "prev" is the top at the start of the last completed marking.
295 // "next" is the top at the start of the in-progress marking (if any.)
296 HeapWord* _prev_top_at_mark_start;
297 HeapWord* _next_top_at_mark_start;
298 // If a collection pause is in progress, this is the top at the start
299 // of that pause.
301 // We've counted the marked bytes of objects below here.
302 HeapWord* _top_at_conc_mark_count;
304 void init_top_at_mark_start() {
305 assert(_prev_marked_bytes == 0 &&
306 _next_marked_bytes == 0,
307 "Must be called after zero_marked_bytes.");
308 HeapWord* bot = bottom();
309 _prev_top_at_mark_start = bot;
310 _next_top_at_mark_start = bot;
311 _top_at_conc_mark_count = bot;
312 }
314 void set_young_type(YoungType new_type) {
315 //assert(_young_type != new_type, "setting the same type" );
316 // TODO: add more assertions here
317 _young_type = new_type;
318 }
320 // Cached attributes used in the collection set policy information
322 // The RSet length that was added to the total value
323 // for the collection set.
324 size_t _recorded_rs_length;
326 // The predicted elapsed time that was added to total value
327 // for the collection set.
328 double _predicted_elapsed_time_ms;
330 // The predicted number of bytes to copy that was added to
331 // the total value for the collection set.
332 size_t _predicted_bytes_to_copy;
334 public:
335 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros.
336 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
337 MemRegion mr, bool is_zeroed);
339 static int LogOfHRGrainBytes;
340 static int LogOfHRGrainWords;
341 // The normal type of these should be size_t. However, they used to
342 // be members of an enum before and they are assumed by the
343 // compilers to be ints. To avoid going and fixing all their uses,
344 // I'm declaring them as ints. I'm not anticipating heap region
345 // sizes to reach anywhere near 2g, so using an int here is safe.
346 static int GrainBytes;
347 static int GrainWords;
348 static int CardsPerRegion;
350 // It sets up the heap region size (GrainBytes / GrainWords), as
351 // well as other related fields that are based on the heap region
352 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
353 // CardsPerRegion). All those fields are considered constant
354 // throughout the JVM's execution, therefore they should only be set
355 // up once during initialization time.
356 static void setup_heap_region_size(uintx min_heap_size);
358 enum ClaimValues {
359 InitialClaimValue = 0,
360 FinalCountClaimValue = 1,
361 NoteEndClaimValue = 2,
362 ScrubRemSetClaimValue = 3,
363 ParVerifyClaimValue = 4,
364 RebuildRSClaimValue = 5
365 };
367 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
368 assert(is_young(), "we can only skip BOT updates on young regions");
369 return ContiguousSpace::par_allocate(word_size);
370 }
371 inline HeapWord* allocate_no_bot_updates(size_t word_size) {
372 assert(is_young(), "we can only skip BOT updates on young regions");
373 return ContiguousSpace::allocate(word_size);
374 }
376 // If this region is a member of a HeapRegionSeq, the index in that
377 // sequence, otherwise -1.
378 int hrs_index() const { return _hrs_index; }
379 void set_hrs_index(int index) { _hrs_index = index; }
381 // The number of bytes marked live in the region in the last marking phase.
382 size_t marked_bytes() { return _prev_marked_bytes; }
383 // The number of bytes counted in the next marking.
384 size_t next_marked_bytes() { return _next_marked_bytes; }
385 // The number of bytes live wrt the next marking.
386 size_t next_live_bytes() {
387 return (top() - next_top_at_mark_start())
388 * HeapWordSize
389 + next_marked_bytes();
390 }
392 // A lower bound on the amount of garbage bytes in the region.
393 size_t garbage_bytes() {
394 size_t used_at_mark_start_bytes =
395 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
396 assert(used_at_mark_start_bytes >= marked_bytes(),
397 "Can't mark more than we have.");
398 return used_at_mark_start_bytes - marked_bytes();
399 }
401 // An upper bound on the number of live bytes in the region.
402 size_t max_live_bytes() { return used() - garbage_bytes(); }
404 void add_to_marked_bytes(size_t incr_bytes) {
405 _next_marked_bytes = _next_marked_bytes + incr_bytes;
406 guarantee( _next_marked_bytes <= used(), "invariant" );
407 }
409 void zero_marked_bytes() {
410 _prev_marked_bytes = _next_marked_bytes = 0;
411 }
413 bool isHumongous() const { return _humongous_type != NotHumongous; }
414 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
415 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
416 // For a humongous region, region in which it starts.
417 HeapRegion* humongous_start_region() const {
418 return _humongous_start_region;
419 }
421 // Makes the current region be a "starts humongous" region, i.e.,
422 // the first region in a series of one or more contiguous regions
423 // that will contain a single "humongous" object. The two parameters
424 // are as follows:
425 //
426 // new_top : The new value of the top field of this region which
427 // points to the end of the humongous object that's being
428 // allocated. If there is more than one region in the series, top
429 // will lie beyond this region's original end field and on the last
430 // region in the series.
431 //
432 // new_end : The new value of the end field of this region which
433 // points to the end of the last region in the series. If there is
434 // one region in the series (namely: this one) end will be the same
435 // as the original end of this region.
436 //
437 // Updating top and end as described above makes this region look as
438 // if it spans the entire space taken up by all the regions in the
439 // series and an single allocation moved its top to new_top. This
440 // ensures that the space (capacity / allocated) taken up by all
441 // humongous regions can be calculated by just looking at the
442 // "starts humongous" regions and by ignoring the "continues
443 // humongous" regions.
444 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
446 // Makes the current region be a "continues humongous'
447 // region. first_hr is the "start humongous" region of the series
448 // which this region will be part of.
449 void set_continuesHumongous(HeapRegion* first_hr);
451 // Unsets the humongous-related fields on the region.
452 void set_notHumongous();
454 // If the region has a remembered set, return a pointer to it.
455 HeapRegionRemSet* rem_set() const {
456 return _rem_set;
457 }
459 // True iff the region is in current collection_set.
460 bool in_collection_set() const {
461 return _in_collection_set;
462 }
463 void set_in_collection_set(bool b) {
464 _in_collection_set = b;
465 }
466 HeapRegion* next_in_collection_set() {
467 assert(in_collection_set(), "should only invoke on member of CS.");
468 assert(_next_in_special_set == NULL ||
469 _next_in_special_set->in_collection_set(),
470 "Malformed CS.");
471 return _next_in_special_set;
472 }
473 void set_next_in_collection_set(HeapRegion* r) {
474 assert(in_collection_set(), "should only invoke on member of CS.");
475 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
476 _next_in_special_set = r;
477 }
479 // True iff it is or has been an allocation region in the current
480 // collection pause.
481 bool is_gc_alloc_region() const {
482 return _is_gc_alloc_region;
483 }
484 void set_is_gc_alloc_region(bool b) {
485 _is_gc_alloc_region = b;
486 }
487 HeapRegion* next_gc_alloc_region() {
488 assert(is_gc_alloc_region(), "should only invoke on member of CS.");
489 assert(_next_in_special_set == NULL ||
490 _next_in_special_set->is_gc_alloc_region(),
491 "Malformed CS.");
492 return _next_in_special_set;
493 }
494 void set_next_gc_alloc_region(HeapRegion* r) {
495 assert(is_gc_alloc_region(), "should only invoke on member of CS.");
496 assert(r == NULL || r->is_gc_alloc_region(), "Malformed CS.");
497 _next_in_special_set = r;
498 }
500 // Methods used by the HeapRegionSetBase class and subclasses.
502 // Getter and setter for the next field used to link regions into
503 // linked lists.
504 HeapRegion* next() { return _next; }
506 void set_next(HeapRegion* next) { _next = next; }
508 // Every region added to a set is tagged with a reference to that
509 // set. This is used for doing consistency checking to make sure that
510 // the contents of a set are as they should be and it's only
511 // available in non-product builds.
512 #ifdef ASSERT
513 void set_containing_set(HeapRegionSetBase* containing_set) {
514 assert((containing_set == NULL && _containing_set != NULL) ||
515 (containing_set != NULL && _containing_set == NULL),
516 err_msg("containing_set: "PTR_FORMAT" "
517 "_containing_set: "PTR_FORMAT,
518 containing_set, _containing_set));
520 _containing_set = containing_set;
521 }
523 HeapRegionSetBase* containing_set() { return _containing_set; }
524 #else // ASSERT
525 void set_containing_set(HeapRegionSetBase* containing_set) { }
527 // containing_set() is only used in asserts so there's not reason
528 // to provide a dummy version of it.
529 #endif // ASSERT
531 // If we want to remove regions from a list in bulk we can simply tag
532 // them with the pending_removal tag and call the
533 // remove_all_pending() method on the list.
535 bool pending_removal() { return _pending_removal; }
537 void set_pending_removal(bool pending_removal) {
538 // We can only set pending_removal to true, if it's false and the
539 // region belongs to a set.
540 assert(!pending_removal ||
541 (!_pending_removal && containing_set() != NULL), "pre-condition");
542 // We can only set pending_removal to false, if it's true and the
543 // region does not belong to a set.
544 assert( pending_removal ||
545 ( _pending_removal && containing_set() == NULL), "pre-condition");
547 _pending_removal = pending_removal;
548 }
550 HeapRegion* get_next_young_region() { return _next_young_region; }
551 void set_next_young_region(HeapRegion* hr) {
552 _next_young_region = hr;
553 }
555 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
556 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
557 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
558 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
560 // Allows logical separation between objects allocated before and after.
561 void save_marks();
563 // Reset HR stuff to default values.
564 void hr_clear(bool par, bool clear_space);
566 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
568 // Get the start of the unmarked area in this region.
569 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
570 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
572 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
573 // allocated in the current region before the last call to "save_mark".
574 void oop_before_save_marks_iterate(OopClosure* cl);
576 // This call determines the "filter kind" argument that will be used for
577 // the next call to "new_dcto_cl" on this region with the "traditional"
578 // signature (i.e., the call below.) The default, in the absence of a
579 // preceding call to this method, is "NoFilterKind", and a call to this
580 // method is necessary for each such call, or else it reverts to the
581 // default.
582 // (This is really ugly, but all other methods I could think of changed a
583 // lot of main-line code for G1.)
584 void set_next_filter_kind(HeapRegionDCTOC::FilterKind nfk) {
585 _next_fk = nfk;
586 }
588 DirtyCardToOopClosure*
589 new_dcto_closure(OopClosure* cl,
590 CardTableModRefBS::PrecisionStyle precision,
591 HeapRegionDCTOC::FilterKind fk);
593 #if WHASSUP
594 DirtyCardToOopClosure*
595 new_dcto_closure(OopClosure* cl,
596 CardTableModRefBS::PrecisionStyle precision,
597 HeapWord* boundary) {
598 assert(boundary == NULL, "This arg doesn't make sense here.");
599 DirtyCardToOopClosure* res = new_dcto_closure(cl, precision, _next_fk);
600 _next_fk = HeapRegionDCTOC::NoFilterKind;
601 return res;
602 }
603 #endif
605 //
606 // Note the start or end of marking. This tells the heap region
607 // that the collector is about to start or has finished (concurrently)
608 // marking the heap.
609 //
611 // Note the start of a marking phase. Record the
612 // start of the unmarked area of the region here.
613 void note_start_of_marking(bool during_initial_mark) {
614 init_top_at_conc_mark_count();
615 _next_marked_bytes = 0;
616 if (during_initial_mark && is_young() && !is_survivor())
617 _next_top_at_mark_start = bottom();
618 else
619 _next_top_at_mark_start = top();
620 }
622 // Note the end of a marking phase. Install the start of
623 // the unmarked area that was captured at start of marking.
624 void note_end_of_marking() {
625 _prev_top_at_mark_start = _next_top_at_mark_start;
626 _prev_marked_bytes = _next_marked_bytes;
627 _next_marked_bytes = 0;
629 guarantee(_prev_marked_bytes <=
630 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize,
631 "invariant");
632 }
634 // After an evacuation, we need to update _next_top_at_mark_start
635 // to be the current top. Note this is only valid if we have only
636 // ever evacuated into this region. If we evacuate, allocate, and
637 // then evacuate we are in deep doodoo.
638 void note_end_of_copying() {
639 assert(top() >= _next_top_at_mark_start, "Increase only");
640 _next_top_at_mark_start = top();
641 }
643 // Returns "false" iff no object in the region was allocated when the
644 // last mark phase ended.
645 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
647 // If "is_marked()" is true, then this is the index of the region in
648 // an array constructed at the end of marking of the regions in a
649 // "desirability" order.
650 int sort_index() {
651 return _sort_index;
652 }
653 void set_sort_index(int i) {
654 _sort_index = i;
655 }
657 void init_top_at_conc_mark_count() {
658 _top_at_conc_mark_count = bottom();
659 }
661 void set_top_at_conc_mark_count(HeapWord *cur) {
662 assert(bottom() <= cur && cur <= end(), "Sanity.");
663 _top_at_conc_mark_count = cur;
664 }
666 HeapWord* top_at_conc_mark_count() {
667 return _top_at_conc_mark_count;
668 }
670 void reset_during_compaction() {
671 guarantee( isHumongous() && startsHumongous(),
672 "should only be called for humongous regions");
674 zero_marked_bytes();
675 init_top_at_mark_start();
676 }
678 // <PREDICTION>
679 void calc_gc_efficiency(void);
680 double gc_efficiency() { return _gc_efficiency;}
681 // </PREDICTION>
683 bool is_young() const { return _young_type != NotYoung; }
684 bool is_survivor() const { return _young_type == Survivor; }
686 int young_index_in_cset() const { return _young_index_in_cset; }
687 void set_young_index_in_cset(int index) {
688 assert( (index == -1) || is_young(), "pre-condition" );
689 _young_index_in_cset = index;
690 }
692 int age_in_surv_rate_group() {
693 assert( _surv_rate_group != NULL, "pre-condition" );
694 assert( _age_index > -1, "pre-condition" );
695 return _surv_rate_group->age_in_group(_age_index);
696 }
698 void record_surv_words_in_group(size_t words_survived) {
699 assert( _surv_rate_group != NULL, "pre-condition" );
700 assert( _age_index > -1, "pre-condition" );
701 int age_in_group = age_in_surv_rate_group();
702 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
703 }
705 int age_in_surv_rate_group_cond() {
706 if (_surv_rate_group != NULL)
707 return age_in_surv_rate_group();
708 else
709 return -1;
710 }
712 SurvRateGroup* surv_rate_group() {
713 return _surv_rate_group;
714 }
716 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
717 assert( surv_rate_group != NULL, "pre-condition" );
718 assert( _surv_rate_group == NULL, "pre-condition" );
719 assert( is_young(), "pre-condition" );
721 _surv_rate_group = surv_rate_group;
722 _age_index = surv_rate_group->next_age_index();
723 }
725 void uninstall_surv_rate_group() {
726 if (_surv_rate_group != NULL) {
727 assert( _age_index > -1, "pre-condition" );
728 assert( is_young(), "pre-condition" );
730 _surv_rate_group = NULL;
731 _age_index = -1;
732 } else {
733 assert( _age_index == -1, "pre-condition" );
734 }
735 }
737 void set_young() { set_young_type(Young); }
739 void set_survivor() { set_young_type(Survivor); }
741 void set_not_young() { set_young_type(NotYoung); }
743 // Determine if an object has been allocated since the last
744 // mark performed by the collector. This returns true iff the object
745 // is within the unmarked area of the region.
746 bool obj_allocated_since_prev_marking(oop obj) const {
747 return (HeapWord *) obj >= prev_top_at_mark_start();
748 }
749 bool obj_allocated_since_next_marking(oop obj) const {
750 return (HeapWord *) obj >= next_top_at_mark_start();
751 }
753 // For parallel heapRegion traversal.
754 bool claimHeapRegion(int claimValue);
755 jint claim_value() { return _claimed; }
756 // Use this carefully: only when you're sure no one is claiming...
757 void set_claim_value(int claimValue) { _claimed = claimValue; }
759 // Returns the "evacuation_failed" property of the region.
760 bool evacuation_failed() { return _evacuation_failed; }
762 // Sets the "evacuation_failed" property of the region.
763 void set_evacuation_failed(bool b) {
764 _evacuation_failed = b;
766 if (b) {
767 init_top_at_conc_mark_count();
768 _next_marked_bytes = 0;
769 }
770 }
772 // Requires that "mr" be entirely within the region.
773 // Apply "cl->do_object" to all objects that intersect with "mr".
774 // If the iteration encounters an unparseable portion of the region,
775 // or if "cl->abort()" is true after a closure application,
776 // terminate the iteration and return the address of the start of the
777 // subregion that isn't done. (The two can be distinguished by querying
778 // "cl->abort()".) Return of "NULL" indicates that the iteration
779 // completed.
780 HeapWord*
781 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
783 // In this version - if filter_young is true and the region
784 // is a young region then we skip the iteration.
785 HeapWord*
786 oops_on_card_seq_iterate_careful(MemRegion mr,
787 FilterOutOfRegionClosure* cl,
788 bool filter_young);
790 // A version of block start that is guaranteed to find *some* block
791 // boundary at or before "p", but does not object iteration, and may
792 // therefore be used safely when the heap is unparseable.
793 HeapWord* block_start_careful(const void* p) const {
794 return _offsets.block_start_careful(p);
795 }
797 // Requires that "addr" is within the region. Returns the start of the
798 // first ("careful") block that starts at or after "addr", or else the
799 // "end" of the region if there is no such block.
800 HeapWord* next_block_start_careful(HeapWord* addr);
802 size_t recorded_rs_length() const { return _recorded_rs_length; }
803 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
804 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
806 void set_recorded_rs_length(size_t rs_length) {
807 _recorded_rs_length = rs_length;
808 }
810 void set_predicted_elapsed_time_ms(double ms) {
811 _predicted_elapsed_time_ms = ms;
812 }
814 void set_predicted_bytes_to_copy(size_t bytes) {
815 _predicted_bytes_to_copy = bytes;
816 }
818 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
819 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
820 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
822 CompactibleSpace* next_compaction_space() const;
824 virtual void reset_after_compaction();
826 void print() const;
827 void print_on(outputStream* st) const;
829 // use_prev_marking == true -> use "prev" marking information,
830 // use_prev_marking == false -> use "next" marking information
831 // NOTE: Only the "prev" marking information is guaranteed to be
832 // consistent most of the time, so most calls to this should use
833 // use_prev_marking == true. Currently, there is only one case where
834 // this is called with use_prev_marking == false, which is to verify
835 // the "next" marking information at the end of remark.
836 void verify(bool allow_dirty, bool use_prev_marking, bool *failures) const;
838 // Override; it uses the "prev" marking information
839 virtual void verify(bool allow_dirty) const;
840 };
842 // HeapRegionClosure is used for iterating over regions.
843 // Terminates the iteration when the "doHeapRegion" method returns "true".
844 class HeapRegionClosure : public StackObj {
845 friend class HeapRegionSeq;
846 friend class G1CollectedHeap;
848 bool _complete;
849 void incomplete() { _complete = false; }
851 public:
852 HeapRegionClosure(): _complete(true) {}
854 // Typically called on each region until it returns true.
855 virtual bool doHeapRegion(HeapRegion* r) = 0;
857 // True after iteration if the closure was applied to all heap regions
858 // and returned "false" in all cases.
859 bool complete() { return _complete; }
860 };
862 #endif // SERIALGC
864 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP