1 /*
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
24
25 #ifndef SERIALGC
26
27 // A HeapRegion is the smallest piece of a G1CollectedHeap that
28 // can be collected independently.
29
30 // NOTE: Although a HeapRegion is a Space, its
31 // Space::initDirtyCardClosure method must not be called.
32 // The problem is that the existence of this method breaks
33 // the independence of barrier sets from remembered sets.
34 // The solution is to remove this method from the definition
35 // of a Space.
36
37 class CompactibleSpace;
38 class ContiguousSpace;
39 class HeapRegionRemSet;
40 class HeapRegionRemSetIterator;
41 class HeapRegion;
42
43 // A dirty card to oop closure for heap regions. It
44 // knows how to get the G1 heap and how to use the bitmap
45 // in the concurrent marker used by G1 to filter remembered
46 // sets.
47
48 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
49 public:
50 // Specification of possible DirtyCardToOopClosure filtering.
51 enum FilterKind {
52 NoFilterKind,
53 IntoCSFilterKind,
54 OutOfRegionFilterKind
55 };
56
57 protected:
58 HeapRegion* _hr;
59 FilterKind _fk;
60 G1CollectedHeap* _g1;
61
62 void walk_mem_region_with_cl(MemRegion mr,
63 HeapWord* bottom, HeapWord* top,
64 OopClosure* cl);
65
66 // We don't specialize this for FilteringClosure; filtering is handled by
67 // the "FilterKind" mechanism. But we provide this to avoid a compiler
68 // warning.
69 void walk_mem_region_with_cl(MemRegion mr,
70 HeapWord* bottom, HeapWord* top,
71 FilteringClosure* cl) {
72 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top,
73 (OopClosure*)cl);
74 }
75
76 // Get the actual top of the area on which the closure will
77 // operate, given where the top is assumed to be (the end of the
78 // memory region passed to do_MemRegion) and where the object
79 // at the top is assumed to start. For example, an object may
80 // start at the top but actually extend past the assumed top,
81 // in which case the top becomes the end of the object.
82 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) {
83 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj);
84 }
85
86 // Walk the given memory region from bottom to (actual) top
87 // looking for objects and applying the oop closure (_cl) to
88 // them. The base implementation of this treats the area as
89 // blocks, where a block may or may not be an object. Sub-
90 // classes should override this to provide more accurate
91 // or possibly more efficient walking.
92 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) {
93 Filtering_DCTOC::walk_mem_region(mr, bottom, top);
94 }
95
96 public:
97 HeapRegionDCTOC(G1CollectedHeap* g1,
98 HeapRegion* hr, OopClosure* cl,
99 CardTableModRefBS::PrecisionStyle precision,
100 FilterKind fk);
101 };
102
103
104 // The complicating factor is that BlockOffsetTable diverged
105 // significantly, and we need functionality that is only in the G1 version.
106 // So I copied that code, which led to an alternate G1 version of
107 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
108 // be reconciled, then G1OffsetTableContigSpace could go away.
109
110 // The idea behind time stamps is the following. Doing a save_marks on
111 // all regions at every GC pause is time consuming (if I remember
112 // well, 10ms or so). So, we would like to do that only for regions
113 // that are GC alloc regions. To achieve this, we use time
114 // stamps. For every evacuation pause, G1CollectedHeap generates a
115 // unique time stamp (essentially a counter that gets
116 // incremented). Every time we want to call save_marks on a region,
117 // we set the saved_mark_word to top and also copy the current GC
118 // time stamp to the time stamp field of the space. Reading the
119 // saved_mark_word involves checking the time stamp of the
120 // region. If it is the same as the current GC time stamp, then we
121 // can safely read the saved_mark_word field, as it is valid. If the
122 // time stamp of the region is not the same as the current GC time
123 // stamp, then we instead read top, as the saved_mark_word field is
124 // invalid. Time stamps (on the regions and also on the
125 // G1CollectedHeap) are reset at every cleanup (we iterate over
126 // the regions anyway) and at the end of a Full GC. The current scheme
127 // that uses sequential unsigned ints will fail only if we have 4b
128 // evacuation pauses between two cleanups, which is _highly_ unlikely.
129
130 class G1OffsetTableContigSpace: public ContiguousSpace {
131 friend class VMStructs;
132 protected:
133 G1BlockOffsetArrayContigSpace _offsets;
134 Mutex _par_alloc_lock;
135 volatile unsigned _gc_time_stamp;
136
137 public:
138 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be
139 // assumed to contain zeros.
140 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
141 MemRegion mr, bool is_zeroed = false);
142
143 void set_bottom(HeapWord* value);
144 void set_end(HeapWord* value);
145
146 virtual HeapWord* saved_mark_word() const;
147 virtual void set_saved_mark();
148 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
149
150 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
151 virtual void clear(bool mangle_space);
152
153 HeapWord* block_start(const void* p);
154 HeapWord* block_start_const(const void* p) const;
155
156 // Add offset table update.
157 virtual HeapWord* allocate(size_t word_size);
158 HeapWord* par_allocate(size_t word_size);
159
160 // MarkSweep support phase3
161 virtual HeapWord* initialize_threshold();
162 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
163
164 virtual void print() const;
165 };
166
167 class HeapRegion: public G1OffsetTableContigSpace {
168 friend class VMStructs;
169 private:
170
171 enum HumongousType {
172 NotHumongous = 0,
173 StartsHumongous,
174 ContinuesHumongous
175 };
176
177 // The next filter kind that should be used for a "new_dcto_cl" call with
178 // the "traditional" signature.
179 HeapRegionDCTOC::FilterKind _next_fk;
180
181 // Requires that the region "mr" be dense with objects, and begin and end
182 // with an object.
183 void oops_in_mr_iterate(MemRegion mr, OopClosure* cl);
184
185 // The remembered set for this region.
186 // (Might want to make this "inline" later, to avoid some alloc failure
187 // issues.)
188 HeapRegionRemSet* _rem_set;
189
190 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
191
192 protected:
193 // If this region is a member of a HeapRegionSeq, the index in that
194 // sequence, otherwise -1.
195 int _hrs_index;
196
197 HumongousType _humongous_type;
198 // For a humongous region, region in which it starts.
199 HeapRegion* _humongous_start_region;
200 // For the start region of a humongous sequence, it's original end().
201 HeapWord* _orig_end;
202
203 // True iff the region is in current collection_set.
204 bool _in_collection_set;
205
206 // True iff the region is on the unclean list, waiting to be zero filled.
207 bool _is_on_unclean_list;
208
209 // True iff the region is on the free list, ready for allocation.
210 bool _is_on_free_list;
211
212 // Is this or has it been an allocation region in the current collection
213 // pause.
214 bool _is_gc_alloc_region;
215
216 // True iff an attempt to evacuate an object in the region failed.
217 bool _evacuation_failed;
218
219 // A heap region may be a member one of a number of special subsets, each
220 // represented as linked lists through the field below. Currently, these
221 // sets include:
222 // The collection set.
223 // The set of allocation regions used in a collection pause.
224 // Spaces that may contain gray objects.
225 HeapRegion* _next_in_special_set;
226
227 // next region in the young "generation" region set
228 HeapRegion* _next_young_region;
229
230 // Next region whose cards need cleaning
231 HeapRegion* _next_dirty_cards_region;
232
233 // For parallel heapRegion traversal.
234 jint _claimed;
235
236 // We use concurrent marking to determine the amount of live data
237 // in each heap region.
238 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
239 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
240
241 // See "sort_index" method. -1 means is not in the array.
242 int _sort_index;
243
244 // <PREDICTION>
245 double _gc_efficiency;
246 // </PREDICTION>
247
248 enum YoungType {
249 NotYoung, // a region is not young
250 Young, // a region is young
251 Survivor // a region is young and it contains
252 // survivor
253 };
254
255 volatile YoungType _young_type;
256 int _young_index_in_cset;
257 SurvRateGroup* _surv_rate_group;
258 int _age_index;
259
260 // The start of the unmarked area. The unmarked area extends from this
261 // word until the top and/or end of the region, and is the part
262 // of the region for which no marking was done, i.e. objects may
263 // have been allocated in this part since the last mark phase.
264 // "prev" is the top at the start of the last completed marking.
265 // "next" is the top at the start of the in-progress marking (if any.)
266 HeapWord* _prev_top_at_mark_start;
267 HeapWord* _next_top_at_mark_start;
268 // If a collection pause is in progress, this is the top at the start
269 // of that pause.
270
271 // We've counted the marked bytes of objects below here.
272 HeapWord* _top_at_conc_mark_count;
273
274 void init_top_at_mark_start() {
275 assert(_prev_marked_bytes == 0 &&
276 _next_marked_bytes == 0,
277 "Must be called after zero_marked_bytes.");
278 HeapWord* bot = bottom();
279 _prev_top_at_mark_start = bot;
280 _next_top_at_mark_start = bot;
281 _top_at_conc_mark_count = bot;
282 }
283
284 jint _zfs; // A member of ZeroFillState. Protected by ZF_lock.
285 Thread* _zero_filler; // If _zfs is ZeroFilling, the thread that (last)
286 // made it so.
287
288 void set_young_type(YoungType new_type) {
289 //assert(_young_type != new_type, "setting the same type" );
290 // TODO: add more assertions here
291 _young_type = new_type;
292 }
293
294 // Cached attributes used in the collection set policy information
295
296 // The RSet length that was added to the total value
297 // for the collection set.
298 size_t _recorded_rs_length;
299
300 // The predicted elapsed time that was added to total value
301 // for the collection set.
302 double _predicted_elapsed_time_ms;
303
304 // The predicted number of bytes to copy that was added to
305 // the total value for the collection set.
306 size_t _predicted_bytes_to_copy;
307
308 public:
309 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros.
310 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
311 MemRegion mr, bool is_zeroed);
312
313 static int LogOfHRGrainBytes;
314 static int LogOfHRGrainWords;
315 // The normal type of these should be size_t. However, they used to
316 // be members of an enum before and they are assumed by the
317 // compilers to be ints. To avoid going and fixing all their uses,
318 // I'm declaring them as ints. I'm not anticipating heap region
319 // sizes to reach anywhere near 2g, so using an int here is safe.
320 static int GrainBytes;
321 static int GrainWords;
322 static int CardsPerRegion;
323
324 // It sets up the heap region size (GrainBytes / GrainWords), as
325 // well as other related fields that are based on the heap region
326 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
327 // CardsPerRegion). All those fields are considered constant
328 // throughout the JVM's execution, therefore they should only be set
329 // up once during initialization time.
330 static void setup_heap_region_size(uintx min_heap_size);
331
332 enum ClaimValues {
333 InitialClaimValue = 0,
334 FinalCountClaimValue = 1,
335 NoteEndClaimValue = 2,
336 ScrubRemSetClaimValue = 3,
337 ParVerifyClaimValue = 4,
338 RebuildRSClaimValue = 5
339 };
340
341 // Concurrent refinement requires contiguous heap regions (in which TLABs
342 // might be allocated) to be zero-filled. Each region therefore has a
343 // zero-fill-state.
344 enum ZeroFillState {
345 NotZeroFilled,
346 ZeroFilling,
347 ZeroFilled,
348 Allocated
349 };
350
351 // If this region is a member of a HeapRegionSeq, the index in that
352 // sequence, otherwise -1.
353 int hrs_index() const { return _hrs_index; }
354 void set_hrs_index(int index) { _hrs_index = index; }
355
356 // The number of bytes marked live in the region in the last marking phase.
357 size_t marked_bytes() { return _prev_marked_bytes; }
358 // The number of bytes counted in the next marking.
359 size_t next_marked_bytes() { return _next_marked_bytes; }
360 // The number of bytes live wrt the next marking.
361 size_t next_live_bytes() {
362 return (top() - next_top_at_mark_start())
363 * HeapWordSize
364 + next_marked_bytes();
365 }
366
367 // A lower bound on the amount of garbage bytes in the region.
368 size_t garbage_bytes() {
369 size_t used_at_mark_start_bytes =
370 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
371 assert(used_at_mark_start_bytes >= marked_bytes(),
372 "Can't mark more than we have.");
373 return used_at_mark_start_bytes - marked_bytes();
374 }
375
376 // An upper bound on the number of live bytes in the region.
377 size_t max_live_bytes() { return used() - garbage_bytes(); }
378
379 void add_to_marked_bytes(size_t incr_bytes) {
380 _next_marked_bytes = _next_marked_bytes + incr_bytes;
381 guarantee( _next_marked_bytes <= used(), "invariant" );
382 }
383
384 void zero_marked_bytes() {
385 _prev_marked_bytes = _next_marked_bytes = 0;
386 }
387
388 bool isHumongous() const { return _humongous_type != NotHumongous; }
389 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
390 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
391 // For a humongous region, region in which it starts.
392 HeapRegion* humongous_start_region() const {
393 return _humongous_start_region;
394 }
395
396 // Causes the current region to represent a humongous object spanning "n"
397 // regions.
398 virtual void set_startsHumongous();
399
400 // The regions that continue a humongous sequence should be added using
401 // this method, in increasing address order.
402 void set_continuesHumongous(HeapRegion* start);
403
404 void add_continuingHumongousRegion(HeapRegion* cont);
405
406 // If the region has a remembered set, return a pointer to it.
407 HeapRegionRemSet* rem_set() const {
408 return _rem_set;
409 }
410
411 // True iff the region is in current collection_set.
412 bool in_collection_set() const {
413 return _in_collection_set;
414 }
415 void set_in_collection_set(bool b) {
416 _in_collection_set = b;
417 }
418 HeapRegion* next_in_collection_set() {
419 assert(in_collection_set(), "should only invoke on member of CS.");
420 assert(_next_in_special_set == NULL ||
421 _next_in_special_set->in_collection_set(),
422 "Malformed CS.");
423 return _next_in_special_set;
424 }
425 void set_next_in_collection_set(HeapRegion* r) {
426 assert(in_collection_set(), "should only invoke on member of CS.");
427 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
428 _next_in_special_set = r;
429 }
430
431 // True iff it is or has been an allocation region in the current
432 // collection pause.
433 bool is_gc_alloc_region() const {
434 return _is_gc_alloc_region;
435 }
436 void set_is_gc_alloc_region(bool b) {
437 _is_gc_alloc_region = b;
438 }
439 HeapRegion* next_gc_alloc_region() {
440 assert(is_gc_alloc_region(), "should only invoke on member of CS.");
441 assert(_next_in_special_set == NULL ||
442 _next_in_special_set->is_gc_alloc_region(),
443 "Malformed CS.");
444 return _next_in_special_set;
445 }
446 void set_next_gc_alloc_region(HeapRegion* r) {
447 assert(is_gc_alloc_region(), "should only invoke on member of CS.");
448 assert(r == NULL || r->is_gc_alloc_region(), "Malformed CS.");
449 _next_in_special_set = r;
450 }
451
452 bool is_on_free_list() {
453 return _is_on_free_list;
454 }
455
456 void set_on_free_list(bool b) {
457 _is_on_free_list = b;
458 }
459
460 HeapRegion* next_from_free_list() {
461 assert(is_on_free_list(),
462 "Should only invoke on free space.");
463 assert(_next_in_special_set == NULL ||
464 _next_in_special_set->is_on_free_list(),
465 "Malformed Free List.");
466 return _next_in_special_set;
467 }
468
469 void set_next_on_free_list(HeapRegion* r) {
470 assert(r == NULL || r->is_on_free_list(), "Malformed free list.");
471 _next_in_special_set = r;
472 }
473
474 bool is_on_unclean_list() {
475 return _is_on_unclean_list;
476 }
477
478 void set_on_unclean_list(bool b);
479
480 HeapRegion* next_from_unclean_list() {
481 assert(is_on_unclean_list(),
482 "Should only invoke on unclean space.");
483 assert(_next_in_special_set == NULL ||
484 _next_in_special_set->is_on_unclean_list(),
485 "Malformed unclean List.");
486 return _next_in_special_set;
487 }
488
489 void set_next_on_unclean_list(HeapRegion* r);
490
491 HeapRegion* get_next_young_region() { return _next_young_region; }
492 void set_next_young_region(HeapRegion* hr) {
493 _next_young_region = hr;
494 }
495
496 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
497 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
498 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
499 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
500
501 // Allows logical separation between objects allocated before and after.
502 void save_marks();
503
504 // Reset HR stuff to default values.
505 void hr_clear(bool par, bool clear_space);
506
507 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
508
509 // Ensure that "this" is zero-filled.
510 void ensure_zero_filled();
511 // This one requires that the calling thread holds ZF_mon.
512 void ensure_zero_filled_locked();
513
514 // Get the start of the unmarked area in this region.
515 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
516 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
517
518 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
519 // allocated in the current region before the last call to "save_mark".
520 void oop_before_save_marks_iterate(OopClosure* cl);
521
522 // This call determines the "filter kind" argument that will be used for
523 // the next call to "new_dcto_cl" on this region with the "traditional"
524 // signature (i.e., the call below.) The default, in the absence of a
525 // preceding call to this method, is "NoFilterKind", and a call to this
526 // method is necessary for each such call, or else it reverts to the
527 // default.
528 // (This is really ugly, but all other methods I could think of changed a
529 // lot of main-line code for G1.)
530 void set_next_filter_kind(HeapRegionDCTOC::FilterKind nfk) {
531 _next_fk = nfk;
532 }
533
534 DirtyCardToOopClosure*
535 new_dcto_closure(OopClosure* cl,
536 CardTableModRefBS::PrecisionStyle precision,
537 HeapRegionDCTOC::FilterKind fk);
538
539 #if WHASSUP
540 DirtyCardToOopClosure*
541 new_dcto_closure(OopClosure* cl,
542 CardTableModRefBS::PrecisionStyle precision,
543 HeapWord* boundary) {
544 assert(boundary == NULL, "This arg doesn't make sense here.");
545 DirtyCardToOopClosure* res = new_dcto_closure(cl, precision, _next_fk);
546 _next_fk = HeapRegionDCTOC::NoFilterKind;
547 return res;
548 }
549 #endif
550
551 //
552 // Note the start or end of marking. This tells the heap region
553 // that the collector is about to start or has finished (concurrently)
554 // marking the heap.
555 //
556
557 // Note the start of a marking phase. Record the
558 // start of the unmarked area of the region here.
559 void note_start_of_marking(bool during_initial_mark) {
560 init_top_at_conc_mark_count();
561 _next_marked_bytes = 0;
562 if (during_initial_mark && is_young() && !is_survivor())
563 _next_top_at_mark_start = bottom();
564 else
565 _next_top_at_mark_start = top();
566 }
567
568 // Note the end of a marking phase. Install the start of
569 // the unmarked area that was captured at start of marking.
570 void note_end_of_marking() {
571 _prev_top_at_mark_start = _next_top_at_mark_start;
572 _prev_marked_bytes = _next_marked_bytes;
573 _next_marked_bytes = 0;
574
575 guarantee(_prev_marked_bytes <=
576 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize,
577 "invariant");
578 }
579
580 // After an evacuation, we need to update _next_top_at_mark_start
581 // to be the current top. Note this is only valid if we have only
582 // ever evacuated into this region. If we evacuate, allocate, and
583 // then evacuate we are in deep doodoo.
584 void note_end_of_copying() {
585 assert(top() >= _next_top_at_mark_start, "Increase only");
586 _next_top_at_mark_start = top();
587 }
588
589 // Returns "false" iff no object in the region was allocated when the
590 // last mark phase ended.
591 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
592
593 // If "is_marked()" is true, then this is the index of the region in
594 // an array constructed at the end of marking of the regions in a
595 // "desirability" order.
596 int sort_index() {
597 return _sort_index;
598 }
599 void set_sort_index(int i) {
600 _sort_index = i;
601 }
602
603 void init_top_at_conc_mark_count() {
604 _top_at_conc_mark_count = bottom();
605 }
606
607 void set_top_at_conc_mark_count(HeapWord *cur) {
608 assert(bottom() <= cur && cur <= end(), "Sanity.");
609 _top_at_conc_mark_count = cur;
610 }
611
612 HeapWord* top_at_conc_mark_count() {
613 return _top_at_conc_mark_count;
614 }
615
616 void reset_during_compaction() {
617 guarantee( isHumongous() && startsHumongous(),
618 "should only be called for humongous regions");
619
620 zero_marked_bytes();
621 init_top_at_mark_start();
622 }
623
624 // <PREDICTION>
625 void calc_gc_efficiency(void);
626 double gc_efficiency() { return _gc_efficiency;}
627 // </PREDICTION>
628
629 bool is_young() const { return _young_type != NotYoung; }
630 bool is_survivor() const { return _young_type == Survivor; }
631
632 int young_index_in_cset() const { return _young_index_in_cset; }
633 void set_young_index_in_cset(int index) {
634 assert( (index == -1) || is_young(), "pre-condition" );
635 _young_index_in_cset = index;
636 }
637
638 int age_in_surv_rate_group() {
639 assert( _surv_rate_group != NULL, "pre-condition" );
640 assert( _age_index > -1, "pre-condition" );
641 return _surv_rate_group->age_in_group(_age_index);
642 }
643
644 void record_surv_words_in_group(size_t words_survived) {
645 assert( _surv_rate_group != NULL, "pre-condition" );
646 assert( _age_index > -1, "pre-condition" );
647 int age_in_group = age_in_surv_rate_group();
648 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
649 }
650
651 int age_in_surv_rate_group_cond() {
652 if (_surv_rate_group != NULL)
653 return age_in_surv_rate_group();
654 else
655 return -1;
656 }
657
658 SurvRateGroup* surv_rate_group() {
659 return _surv_rate_group;
660 }
661
662 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
663 assert( surv_rate_group != NULL, "pre-condition" );
664 assert( _surv_rate_group == NULL, "pre-condition" );
665 assert( is_young(), "pre-condition" );
666
667 _surv_rate_group = surv_rate_group;
668 _age_index = surv_rate_group->next_age_index();
669 }
670
671 void uninstall_surv_rate_group() {
672 if (_surv_rate_group != NULL) {
673 assert( _age_index > -1, "pre-condition" );
674 assert( is_young(), "pre-condition" );
675
676 _surv_rate_group = NULL;
677 _age_index = -1;
678 } else {
679 assert( _age_index == -1, "pre-condition" );
680 }
681 }
682
683 void set_young() { set_young_type(Young); }
684
685 void set_survivor() { set_young_type(Survivor); }
686
687 void set_not_young() { set_young_type(NotYoung); }
688
689 // Determine if an object has been allocated since the last
690 // mark performed by the collector. This returns true iff the object
691 // is within the unmarked area of the region.
692 bool obj_allocated_since_prev_marking(oop obj) const {
693 return (HeapWord *) obj >= prev_top_at_mark_start();
694 }
695 bool obj_allocated_since_next_marking(oop obj) const {
696 return (HeapWord *) obj >= next_top_at_mark_start();
697 }
698
699 // For parallel heapRegion traversal.
700 bool claimHeapRegion(int claimValue);
701 jint claim_value() { return _claimed; }
702 // Use this carefully: only when you're sure no one is claiming...
703 void set_claim_value(int claimValue) { _claimed = claimValue; }
704
705 // Returns the "evacuation_failed" property of the region.
706 bool evacuation_failed() { return _evacuation_failed; }
707
708 // Sets the "evacuation_failed" property of the region.
709 void set_evacuation_failed(bool b) {
710 _evacuation_failed = b;
711
712 if (b) {
713 init_top_at_conc_mark_count();
714 _next_marked_bytes = 0;
715 }
716 }
717
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);
728
729 // In this version - if filter_young is true and the region
730 // is a young region then we skip the iteration.
731 HeapWord*
732 oops_on_card_seq_iterate_careful(MemRegion mr,
733 FilterOutOfRegionClosure* cl,
734 bool filter_young);
735
736 // The region "mr" is entirely in "this", and starts and ends at block
737 // boundaries. The caller declares that all the contained blocks are
738 // coalesced into one.
739 void declare_filled_region_to_BOT(MemRegion mr) {
740 _offsets.single_block(mr.start(), mr.end());
741 }
742
743 // A version of block start that is guaranteed to find *some* block
744 // boundary at or before "p", but does not object iteration, and may
745 // therefore be used safely when the heap is unparseable.
746 HeapWord* block_start_careful(const void* p) const {
747 return _offsets.block_start_careful(p);
748 }
749
750 // Requires that "addr" is within the region. Returns the start of the
751 // first ("careful") block that starts at or after "addr", or else the
752 // "end" of the region if there is no such block.
753 HeapWord* next_block_start_careful(HeapWord* addr);
754
755 // Returns the zero-fill-state of the current region.
756 ZeroFillState zero_fill_state() { return (ZeroFillState)_zfs; }
757 bool zero_fill_is_allocated() { return _zfs == Allocated; }
758 Thread* zero_filler() { return _zero_filler; }
759
760 // Indicate that the contents of the region are unknown, and therefore
761 // might require zero-filling.
762 void set_zero_fill_needed() {
763 set_zero_fill_state_work(NotZeroFilled);
764 }
765 void set_zero_fill_in_progress(Thread* t) {
766 set_zero_fill_state_work(ZeroFilling);
767 _zero_filler = t;
768 }
769 void set_zero_fill_complete();
770 void set_zero_fill_allocated() {
771 set_zero_fill_state_work(Allocated);
772 }
773
774 void set_zero_fill_state_work(ZeroFillState zfs);
775
776 // This is called when a full collection shrinks the heap.
777 // We want to set the heap region to a value which says
778 // it is no longer part of the heap. For now, we'll let "NotZF" fill
779 // that role.
780 void reset_zero_fill() {
781 set_zero_fill_state_work(NotZeroFilled);
782 _zero_filler = NULL;
783 }
784
785 size_t recorded_rs_length() const { return _recorded_rs_length; }
786 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
787 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
788
789 void set_recorded_rs_length(size_t rs_length) {
790 _recorded_rs_length = rs_length;
791 }
792
793 void set_predicted_elapsed_time_ms(double ms) {
794 _predicted_elapsed_time_ms = ms;
795 }
796
797 void set_predicted_bytes_to_copy(size_t bytes) {
798 _predicted_bytes_to_copy = bytes;
799 }
800
801 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
802 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
803 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
804
805 CompactibleSpace* next_compaction_space() const;
806
807 virtual void reset_after_compaction();
808
809 void print() const;
810 void print_on(outputStream* st) const;
811
812 // use_prev_marking == true -> use "prev" marking information,
813 // use_prev_marking == false -> use "next" marking information
814 // NOTE: Only the "prev" marking information is guaranteed to be
815 // consistent most of the time, so most calls to this should use
816 // use_prev_marking == true. Currently, there is only one case where
817 // this is called with use_prev_marking == false, which is to verify
818 // the "next" marking information at the end of remark.
819 void verify(bool allow_dirty, bool use_prev_marking, bool *failures) const;
820
821 // Override; it uses the "prev" marking information
822 virtual void verify(bool allow_dirty) const;
823
824 #ifdef DEBUG
825 HeapWord* allocate(size_t size);
826 #endif
827 };
828
829 // HeapRegionClosure is used for iterating over regions.
830 // Terminates the iteration when the "doHeapRegion" method returns "true".
831 class HeapRegionClosure : public StackObj {
832 friend class HeapRegionSeq;
833 friend class G1CollectedHeap;
834
835 bool _complete;
836 void incomplete() { _complete = false; }
837
838 public:
839 HeapRegionClosure(): _complete(true) {}
840
841 // Typically called on each region until it returns true.
842 virtual bool doHeapRegion(HeapRegion* r) = 0;
843
844 // True after iteration if the closure was applied to all heap regions
845 // and returned "false" in all cases.
846 bool complete() { return _complete; }
847 };
848
849 // A linked lists of heap regions. It leaves the "next" field
850 // unspecified; that's up to subtypes.
851 class RegionList VALUE_OBJ_CLASS_SPEC {
852 protected:
853 virtual HeapRegion* get_next(HeapRegion* chr) = 0;
854 virtual void set_next(HeapRegion* chr,
855 HeapRegion* new_next) = 0;
856
857 HeapRegion* _hd;
858 HeapRegion* _tl;
859 size_t _sz;
860
861 // Protected constructor because this type is only meaningful
862 // when the _get/_set next functions are defined.
863 RegionList() : _hd(NULL), _tl(NULL), _sz(0) {}
864 public:
865 void reset() {
866 _hd = NULL;
867 _tl = NULL;
868 _sz = 0;
869 }
870 HeapRegion* hd() { return _hd; }
871 HeapRegion* tl() { return _tl; }
872 size_t sz() { return _sz; }
873 size_t length();
874
875 bool well_formed() {
876 return
877 ((hd() == NULL && tl() == NULL && sz() == 0)
878 || (hd() != NULL && tl() != NULL && sz() > 0))
879 && (sz() == length());
880 }
881 virtual void insert_before_head(HeapRegion* r);
882 void prepend_list(RegionList* new_list);
883 virtual HeapRegion* pop();
884 void dec_sz() { _sz--; }
885 // Requires that "r" is an element of the list, and is not the tail.
886 void delete_after(HeapRegion* r);
887 };
888
889 class EmptyNonHRegionList: public RegionList {
890 protected:
891 // Protected constructor because this type is only meaningful
892 // when the _get/_set next functions are defined.
893 EmptyNonHRegionList() : RegionList() {}
894
895 public:
896 void insert_before_head(HeapRegion* r) {
897 // assert(r->is_empty(), "Better be empty");
898 assert(!r->isHumongous(), "Better not be humongous.");
899 RegionList::insert_before_head(r);
900 }
901 void prepend_list(EmptyNonHRegionList* new_list) {
902 // assert(new_list->hd() == NULL || new_list->hd()->is_empty(),
903 // "Better be empty");
904 assert(new_list->hd() == NULL || !new_list->hd()->isHumongous(),
905 "Better not be humongous.");
906 // assert(new_list->tl() == NULL || new_list->tl()->is_empty(),
907 // "Better be empty");
908 assert(new_list->tl() == NULL || !new_list->tl()->isHumongous(),
909 "Better not be humongous.");
910 RegionList::prepend_list(new_list);
911 }
912 };
913
914 class UncleanRegionList: public EmptyNonHRegionList {
915 public:
916 HeapRegion* get_next(HeapRegion* hr) {
917 return hr->next_from_unclean_list();
918 }
919 void set_next(HeapRegion* hr, HeapRegion* new_next) {
920 hr->set_next_on_unclean_list(new_next);
921 }
922
923 UncleanRegionList() : EmptyNonHRegionList() {}
924
925 void insert_before_head(HeapRegion* r) {
926 assert(!r->is_on_free_list(),
927 "Better not already be on free list");
928 assert(!r->is_on_unclean_list(),
929 "Better not already be on unclean list");
930 r->set_zero_fill_needed();
931 r->set_on_unclean_list(true);
932 EmptyNonHRegionList::insert_before_head(r);
933 }
934 void prepend_list(UncleanRegionList* new_list) {
935 assert(new_list->tl() == NULL || !new_list->tl()->is_on_free_list(),
936 "Better not already be on free list");
937 assert(new_list->tl() == NULL || new_list->tl()->is_on_unclean_list(),
938 "Better already be marked as on unclean list");
939 assert(new_list->hd() == NULL || !new_list->hd()->is_on_free_list(),
940 "Better not already be on free list");
941 assert(new_list->hd() == NULL || new_list->hd()->is_on_unclean_list(),
942 "Better already be marked as on unclean list");
943 EmptyNonHRegionList::prepend_list(new_list);
944 }
945 HeapRegion* pop() {
946 HeapRegion* res = RegionList::pop();
947 if (res != NULL) res->set_on_unclean_list(false);
948 return res;
949 }
950 };
951
952 // Local Variables: ***
953 // c-indentation-style: gnu ***
954 // End: ***
955
956 #endif // SERIALGC