Tue, 05 May 2009 22:15:35 -0700
6833576: G1: assert illegal index, growableArray.hpp:186
Summary: The code that calculates the heap region index for an object address incorrectly used signed arithmetic.
Reviewed-by: jcoomes, ysr
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. 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,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
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23 */
25 #ifndef SERIALGC
27 // A HeapRegion is the smallest piece of a G1CollectedHeap that
28 // can be collected independently.
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.
37 class CompactibleSpace;
38 class ContiguousSpace;
39 class HeapRegionRemSet;
40 class HeapRegionRemSetIterator;
41 class HeapRegion;
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.
48 class HeapRegionDCTOC : public ContiguousSpaceDCTOC {
49 public:
50 // Specification of possible DirtyCardToOopClosure filtering.
51 enum FilterKind {
52 NoFilterKind,
53 IntoCSFilterKind,
54 OutOfRegionFilterKind
55 };
57 protected:
58 HeapRegion* _hr;
59 FilterKind _fk;
60 G1CollectedHeap* _g1;
62 void walk_mem_region_with_cl(MemRegion mr,
63 HeapWord* bottom, HeapWord* top,
64 OopClosure* cl);
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 }
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 }
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 }
96 public:
97 HeapRegionDCTOC(G1CollectedHeap* g1,
98 HeapRegion* hr, OopClosure* cl,
99 CardTableModRefBS::PrecisionStyle precision,
100 FilterKind fk);
101 };
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.
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.
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;
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);
143 void set_bottom(HeapWord* value);
144 void set_end(HeapWord* value);
146 virtual HeapWord* saved_mark_word() const;
147 virtual void set_saved_mark();
148 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
150 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
151 virtual void clear(bool mangle_space);
153 HeapWord* block_start(const void* p);
154 HeapWord* block_start_const(const void* p) const;
156 // Add offset table update.
157 virtual HeapWord* allocate(size_t word_size);
158 HeapWord* par_allocate(size_t word_size);
160 // MarkSweep support phase3
161 virtual HeapWord* initialize_threshold();
162 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
164 virtual void print() const;
165 };
167 class HeapRegion: public G1OffsetTableContigSpace {
168 friend class VMStructs;
169 private:
171 enum HumongousType {
172 NotHumongous = 0,
173 StartsHumongous,
174 ContinuesHumongous
175 };
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;
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);
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;
190 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
192 protected:
193 // If this region is a member of a HeapRegionSeq, the index in that
194 // sequence, otherwise -1.
195 int _hrs_index;
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;
203 // True iff the region is in current collection_set.
204 bool _in_collection_set;
206 // True iff the region is on the unclean list, waiting to be zero filled.
207 bool _is_on_unclean_list;
209 // True iff the region is on the free list, ready for allocation.
210 bool _is_on_free_list;
212 // Is this or has it been an allocation region in the current collection
213 // pause.
214 bool _is_gc_alloc_region;
216 // True iff an attempt to evacuate an object in the region failed.
217 bool _evacuation_failed;
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;
227 // next region in the young "generation" region set
228 HeapRegion* _next_young_region;
230 // For parallel heapRegion traversal.
231 jint _claimed;
233 // We use concurrent marking to determine the amount of live data
234 // in each heap region.
235 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
236 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
238 // See "sort_index" method. -1 means is not in the array.
239 int _sort_index;
241 // <PREDICTION>
242 double _gc_efficiency;
243 // </PREDICTION>
245 enum YoungType {
246 NotYoung, // a region is not young
247 ScanOnly, // a region is young and scan-only
248 Young, // a region is young
249 Survivor // a region is young and it contains
250 // survivor
251 };
253 YoungType _young_type;
254 int _young_index_in_cset;
255 SurvRateGroup* _surv_rate_group;
256 int _age_index;
258 // The start of the unmarked area. The unmarked area extends from this
259 // word until the top and/or end of the region, and is the part
260 // of the region for which no marking was done, i.e. objects may
261 // have been allocated in this part since the last mark phase.
262 // "prev" is the top at the start of the last completed marking.
263 // "next" is the top at the start of the in-progress marking (if any.)
264 HeapWord* _prev_top_at_mark_start;
265 HeapWord* _next_top_at_mark_start;
266 // If a collection pause is in progress, this is the top at the start
267 // of that pause.
269 // We've counted the marked bytes of objects below here.
270 HeapWord* _top_at_conc_mark_count;
272 void init_top_at_mark_start() {
273 assert(_prev_marked_bytes == 0 &&
274 _next_marked_bytes == 0,
275 "Must be called after zero_marked_bytes.");
276 HeapWord* bot = bottom();
277 _prev_top_at_mark_start = bot;
278 _next_top_at_mark_start = bot;
279 _top_at_conc_mark_count = bot;
280 }
282 jint _zfs; // A member of ZeroFillState. Protected by ZF_lock.
283 Thread* _zero_filler; // If _zfs is ZeroFilling, the thread that (last)
284 // made it so.
286 void set_young_type(YoungType new_type) {
287 //assert(_young_type != new_type, "setting the same type" );
288 // TODO: add more assertions here
289 _young_type = new_type;
290 }
292 public:
293 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros.
294 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
295 MemRegion mr, bool is_zeroed);
297 enum SomePublicConstants {
298 // HeapRegions are GrainBytes-aligned
299 // and have sizes that are multiples of GrainBytes.
300 LogOfHRGrainBytes = 20,
301 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize,
302 GrainBytes = 1 << LogOfHRGrainBytes,
303 GrainWords = 1 <<LogOfHRGrainWords,
304 MaxAge = 2, NoOfAges = MaxAge+1
305 };
307 enum ClaimValues {
308 InitialClaimValue = 0,
309 FinalCountClaimValue = 1,
310 NoteEndClaimValue = 2,
311 ScrubRemSetClaimValue = 3,
312 ParVerifyClaimValue = 4,
313 RebuildRSClaimValue = 5
314 };
316 // Concurrent refinement requires contiguous heap regions (in which TLABs
317 // might be allocated) to be zero-filled. Each region therefore has a
318 // zero-fill-state.
319 enum ZeroFillState {
320 NotZeroFilled,
321 ZeroFilling,
322 ZeroFilled,
323 Allocated
324 };
326 // If this region is a member of a HeapRegionSeq, the index in that
327 // sequence, otherwise -1.
328 int hrs_index() const { return _hrs_index; }
329 void set_hrs_index(int index) { _hrs_index = index; }
331 // The number of bytes marked live in the region in the last marking phase.
332 size_t marked_bytes() { return _prev_marked_bytes; }
333 // The number of bytes counted in the next marking.
334 size_t next_marked_bytes() { return _next_marked_bytes; }
335 // The number of bytes live wrt the next marking.
336 size_t next_live_bytes() {
337 return (top() - next_top_at_mark_start())
338 * HeapWordSize
339 + next_marked_bytes();
340 }
342 // A lower bound on the amount of garbage bytes in the region.
343 size_t garbage_bytes() {
344 size_t used_at_mark_start_bytes =
345 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
346 assert(used_at_mark_start_bytes >= marked_bytes(),
347 "Can't mark more than we have.");
348 return used_at_mark_start_bytes - marked_bytes();
349 }
351 // An upper bound on the number of live bytes in the region.
352 size_t max_live_bytes() { return used() - garbage_bytes(); }
354 void add_to_marked_bytes(size_t incr_bytes) {
355 _next_marked_bytes = _next_marked_bytes + incr_bytes;
356 guarantee( _next_marked_bytes <= used(), "invariant" );
357 }
359 void zero_marked_bytes() {
360 _prev_marked_bytes = _next_marked_bytes = 0;
361 }
363 bool isHumongous() const { return _humongous_type != NotHumongous; }
364 bool startsHumongous() const { return _humongous_type == StartsHumongous; }
365 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; }
366 // For a humongous region, region in which it starts.
367 HeapRegion* humongous_start_region() const {
368 return _humongous_start_region;
369 }
371 // Causes the current region to represent a humongous object spanning "n"
372 // regions.
373 virtual void set_startsHumongous();
375 // The regions that continue a humongous sequence should be added using
376 // this method, in increasing address order.
377 void set_continuesHumongous(HeapRegion* start);
379 void add_continuingHumongousRegion(HeapRegion* cont);
381 // If the region has a remembered set, return a pointer to it.
382 HeapRegionRemSet* rem_set() const {
383 return _rem_set;
384 }
386 // True iff the region is in current collection_set.
387 bool in_collection_set() const {
388 return _in_collection_set;
389 }
390 void set_in_collection_set(bool b) {
391 _in_collection_set = b;
392 }
393 HeapRegion* next_in_collection_set() {
394 assert(in_collection_set(), "should only invoke on member of CS.");
395 assert(_next_in_special_set == NULL ||
396 _next_in_special_set->in_collection_set(),
397 "Malformed CS.");
398 return _next_in_special_set;
399 }
400 void set_next_in_collection_set(HeapRegion* r) {
401 assert(in_collection_set(), "should only invoke on member of CS.");
402 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
403 _next_in_special_set = r;
404 }
406 // True iff it is or has been an allocation region in the current
407 // collection pause.
408 bool is_gc_alloc_region() const {
409 return _is_gc_alloc_region;
410 }
411 void set_is_gc_alloc_region(bool b) {
412 _is_gc_alloc_region = b;
413 }
414 HeapRegion* next_gc_alloc_region() {
415 assert(is_gc_alloc_region(), "should only invoke on member of CS.");
416 assert(_next_in_special_set == NULL ||
417 _next_in_special_set->is_gc_alloc_region(),
418 "Malformed CS.");
419 return _next_in_special_set;
420 }
421 void set_next_gc_alloc_region(HeapRegion* r) {
422 assert(is_gc_alloc_region(), "should only invoke on member of CS.");
423 assert(r == NULL || r->is_gc_alloc_region(), "Malformed CS.");
424 _next_in_special_set = r;
425 }
427 bool is_on_free_list() {
428 return _is_on_free_list;
429 }
431 void set_on_free_list(bool b) {
432 _is_on_free_list = b;
433 }
435 HeapRegion* next_from_free_list() {
436 assert(is_on_free_list(),
437 "Should only invoke on free space.");
438 assert(_next_in_special_set == NULL ||
439 _next_in_special_set->is_on_free_list(),
440 "Malformed Free List.");
441 return _next_in_special_set;
442 }
444 void set_next_on_free_list(HeapRegion* r) {
445 assert(r == NULL || r->is_on_free_list(), "Malformed free list.");
446 _next_in_special_set = r;
447 }
449 bool is_on_unclean_list() {
450 return _is_on_unclean_list;
451 }
453 void set_on_unclean_list(bool b);
455 HeapRegion* next_from_unclean_list() {
456 assert(is_on_unclean_list(),
457 "Should only invoke on unclean space.");
458 assert(_next_in_special_set == NULL ||
459 _next_in_special_set->is_on_unclean_list(),
460 "Malformed unclean List.");
461 return _next_in_special_set;
462 }
464 void set_next_on_unclean_list(HeapRegion* r);
466 HeapRegion* get_next_young_region() { return _next_young_region; }
467 void set_next_young_region(HeapRegion* hr) {
468 _next_young_region = hr;
469 }
471 // Allows logical separation between objects allocated before and after.
472 void save_marks();
474 // Reset HR stuff to default values.
475 void hr_clear(bool par, bool clear_space);
477 void initialize(MemRegion mr, bool clear_space, bool mangle_space);
479 // Ensure that "this" is zero-filled.
480 void ensure_zero_filled();
481 // This one requires that the calling thread holds ZF_mon.
482 void ensure_zero_filled_locked();
484 // Get the start of the unmarked area in this region.
485 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
486 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
488 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects
489 // allocated in the current region before the last call to "save_mark".
490 void oop_before_save_marks_iterate(OopClosure* cl);
492 // This call determines the "filter kind" argument that will be used for
493 // the next call to "new_dcto_cl" on this region with the "traditional"
494 // signature (i.e., the call below.) The default, in the absence of a
495 // preceding call to this method, is "NoFilterKind", and a call to this
496 // method is necessary for each such call, or else it reverts to the
497 // default.
498 // (This is really ugly, but all other methods I could think of changed a
499 // lot of main-line code for G1.)
500 void set_next_filter_kind(HeapRegionDCTOC::FilterKind nfk) {
501 _next_fk = nfk;
502 }
504 DirtyCardToOopClosure*
505 new_dcto_closure(OopClosure* cl,
506 CardTableModRefBS::PrecisionStyle precision,
507 HeapRegionDCTOC::FilterKind fk);
509 #if WHASSUP
510 DirtyCardToOopClosure*
511 new_dcto_closure(OopClosure* cl,
512 CardTableModRefBS::PrecisionStyle precision,
513 HeapWord* boundary) {
514 assert(boundary == NULL, "This arg doesn't make sense here.");
515 DirtyCardToOopClosure* res = new_dcto_closure(cl, precision, _next_fk);
516 _next_fk = HeapRegionDCTOC::NoFilterKind;
517 return res;
518 }
519 #endif
521 //
522 // Note the start or end of marking. This tells the heap region
523 // that the collector is about to start or has finished (concurrently)
524 // marking the heap.
525 //
527 // Note the start of a marking phase. Record the
528 // start of the unmarked area of the region here.
529 void note_start_of_marking(bool during_initial_mark) {
530 init_top_at_conc_mark_count();
531 _next_marked_bytes = 0;
532 if (during_initial_mark && is_young() && !is_survivor())
533 _next_top_at_mark_start = bottom();
534 else
535 _next_top_at_mark_start = top();
536 }
538 // Note the end of a marking phase. Install the start of
539 // the unmarked area that was captured at start of marking.
540 void note_end_of_marking() {
541 _prev_top_at_mark_start = _next_top_at_mark_start;
542 _prev_marked_bytes = _next_marked_bytes;
543 _next_marked_bytes = 0;
545 guarantee(_prev_marked_bytes <=
546 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize,
547 "invariant");
548 }
550 // After an evacuation, we need to update _next_top_at_mark_start
551 // to be the current top. Note this is only valid if we have only
552 // ever evacuated into this region. If we evacuate, allocate, and
553 // then evacuate we are in deep doodoo.
554 void note_end_of_copying() {
555 assert(top() >= _next_top_at_mark_start,
556 "Increase only");
557 // Survivor regions will be scanned on the start of concurrent
558 // marking.
559 if (!is_survivor()) {
560 _next_top_at_mark_start = top();
561 }
562 }
564 // Returns "false" iff no object in the region was allocated when the
565 // last mark phase ended.
566 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
568 // If "is_marked()" is true, then this is the index of the region in
569 // an array constructed at the end of marking of the regions in a
570 // "desirability" order.
571 int sort_index() {
572 return _sort_index;
573 }
574 void set_sort_index(int i) {
575 _sort_index = i;
576 }
578 void init_top_at_conc_mark_count() {
579 _top_at_conc_mark_count = bottom();
580 }
582 void set_top_at_conc_mark_count(HeapWord *cur) {
583 assert(bottom() <= cur && cur <= end(), "Sanity.");
584 _top_at_conc_mark_count = cur;
585 }
587 HeapWord* top_at_conc_mark_count() {
588 return _top_at_conc_mark_count;
589 }
591 void reset_during_compaction() {
592 guarantee( isHumongous() && startsHumongous(),
593 "should only be called for humongous regions");
595 zero_marked_bytes();
596 init_top_at_mark_start();
597 }
599 // <PREDICTION>
600 void calc_gc_efficiency(void);
601 double gc_efficiency() { return _gc_efficiency;}
602 // </PREDICTION>
604 bool is_young() const { return _young_type != NotYoung; }
605 bool is_scan_only() const { return _young_type == ScanOnly; }
606 bool is_survivor() const { return _young_type == Survivor; }
608 int young_index_in_cset() const { return _young_index_in_cset; }
609 void set_young_index_in_cset(int index) {
610 assert( (index == -1) || is_young(), "pre-condition" );
611 _young_index_in_cset = index;
612 }
614 int age_in_surv_rate_group() {
615 assert( _surv_rate_group != NULL, "pre-condition" );
616 assert( _age_index > -1, "pre-condition" );
617 return _surv_rate_group->age_in_group(_age_index);
618 }
620 void recalculate_age_in_surv_rate_group() {
621 assert( _surv_rate_group != NULL, "pre-condition" );
622 assert( _age_index > -1, "pre-condition" );
623 _age_index = _surv_rate_group->recalculate_age_index(_age_index);
624 }
626 void record_surv_words_in_group(size_t words_survived) {
627 assert( _surv_rate_group != NULL, "pre-condition" );
628 assert( _age_index > -1, "pre-condition" );
629 int age_in_group = age_in_surv_rate_group();
630 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
631 }
633 int age_in_surv_rate_group_cond() {
634 if (_surv_rate_group != NULL)
635 return age_in_surv_rate_group();
636 else
637 return -1;
638 }
640 SurvRateGroup* surv_rate_group() {
641 return _surv_rate_group;
642 }
644 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
645 assert( surv_rate_group != NULL, "pre-condition" );
646 assert( _surv_rate_group == NULL, "pre-condition" );
647 assert( is_young(), "pre-condition" );
649 _surv_rate_group = surv_rate_group;
650 _age_index = surv_rate_group->next_age_index();
651 }
653 void uninstall_surv_rate_group() {
654 if (_surv_rate_group != NULL) {
655 assert( _age_index > -1, "pre-condition" );
656 assert( is_young(), "pre-condition" );
658 _surv_rate_group = NULL;
659 _age_index = -1;
660 } else {
661 assert( _age_index == -1, "pre-condition" );
662 }
663 }
665 void set_young() { set_young_type(Young); }
667 void set_scan_only() { set_young_type(ScanOnly); }
669 void set_survivor() { set_young_type(Survivor); }
671 void set_not_young() { set_young_type(NotYoung); }
673 // Determine if an object has been allocated since the last
674 // mark performed by the collector. This returns true iff the object
675 // is within the unmarked area of the region.
676 bool obj_allocated_since_prev_marking(oop obj) const {
677 return (HeapWord *) obj >= prev_top_at_mark_start();
678 }
679 bool obj_allocated_since_next_marking(oop obj) const {
680 return (HeapWord *) obj >= next_top_at_mark_start();
681 }
683 // For parallel heapRegion traversal.
684 bool claimHeapRegion(int claimValue);
685 jint claim_value() { return _claimed; }
686 // Use this carefully: only when you're sure no one is claiming...
687 void set_claim_value(int claimValue) { _claimed = claimValue; }
689 // Returns the "evacuation_failed" property of the region.
690 bool evacuation_failed() { return _evacuation_failed; }
692 // Sets the "evacuation_failed" property of the region.
693 void set_evacuation_failed(bool b) {
694 _evacuation_failed = b;
696 if (b) {
697 init_top_at_conc_mark_count();
698 _next_marked_bytes = 0;
699 }
700 }
702 // Requires that "mr" be entirely within the region.
703 // Apply "cl->do_object" to all objects that intersect with "mr".
704 // If the iteration encounters an unparseable portion of the region,
705 // or if "cl->abort()" is true after a closure application,
706 // terminate the iteration and return the address of the start of the
707 // subregion that isn't done. (The two can be distinguished by querying
708 // "cl->abort()".) Return of "NULL" indicates that the iteration
709 // completed.
710 HeapWord*
711 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
713 HeapWord*
714 oops_on_card_seq_iterate_careful(MemRegion mr,
715 FilterOutOfRegionClosure* cl);
717 // The region "mr" is entirely in "this", and starts and ends at block
718 // boundaries. The caller declares that all the contained blocks are
719 // coalesced into one.
720 void declare_filled_region_to_BOT(MemRegion mr) {
721 _offsets.single_block(mr.start(), mr.end());
722 }
724 // A version of block start that is guaranteed to find *some* block
725 // boundary at or before "p", but does not object iteration, and may
726 // therefore be used safely when the heap is unparseable.
727 HeapWord* block_start_careful(const void* p) const {
728 return _offsets.block_start_careful(p);
729 }
731 // Requires that "addr" is within the region. Returns the start of the
732 // first ("careful") block that starts at or after "addr", or else the
733 // "end" of the region if there is no such block.
734 HeapWord* next_block_start_careful(HeapWord* addr);
736 // Returns the zero-fill-state of the current region.
737 ZeroFillState zero_fill_state() { return (ZeroFillState)_zfs; }
738 bool zero_fill_is_allocated() { return _zfs == Allocated; }
739 Thread* zero_filler() { return _zero_filler; }
741 // Indicate that the contents of the region are unknown, and therefore
742 // might require zero-filling.
743 void set_zero_fill_needed() {
744 set_zero_fill_state_work(NotZeroFilled);
745 }
746 void set_zero_fill_in_progress(Thread* t) {
747 set_zero_fill_state_work(ZeroFilling);
748 _zero_filler = t;
749 }
750 void set_zero_fill_complete();
751 void set_zero_fill_allocated() {
752 set_zero_fill_state_work(Allocated);
753 }
755 void set_zero_fill_state_work(ZeroFillState zfs);
757 // This is called when a full collection shrinks the heap.
758 // We want to set the heap region to a value which says
759 // it is no longer part of the heap. For now, we'll let "NotZF" fill
760 // that role.
761 void reset_zero_fill() {
762 set_zero_fill_state_work(NotZeroFilled);
763 _zero_filler = NULL;
764 }
766 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
767 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
768 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
770 CompactibleSpace* next_compaction_space() const;
772 virtual void reset_after_compaction();
774 void print() const;
775 void print_on(outputStream* st) const;
777 // Override
778 virtual void verify(bool allow_dirty) const;
780 #ifdef DEBUG
781 HeapWord* allocate(size_t size);
782 #endif
783 };
785 // HeapRegionClosure is used for iterating over regions.
786 // Terminates the iteration when the "doHeapRegion" method returns "true".
787 class HeapRegionClosure : public StackObj {
788 friend class HeapRegionSeq;
789 friend class G1CollectedHeap;
791 bool _complete;
792 void incomplete() { _complete = false; }
794 public:
795 HeapRegionClosure(): _complete(true) {}
797 // Typically called on each region until it returns true.
798 virtual bool doHeapRegion(HeapRegion* r) = 0;
800 // True after iteration if the closure was applied to all heap regions
801 // and returned "false" in all cases.
802 bool complete() { return _complete; }
803 };
805 // A linked lists of heap regions. It leaves the "next" field
806 // unspecified; that's up to subtypes.
807 class RegionList VALUE_OBJ_CLASS_SPEC {
808 protected:
809 virtual HeapRegion* get_next(HeapRegion* chr) = 0;
810 virtual void set_next(HeapRegion* chr,
811 HeapRegion* new_next) = 0;
813 HeapRegion* _hd;
814 HeapRegion* _tl;
815 size_t _sz;
817 // Protected constructor because this type is only meaningful
818 // when the _get/_set next functions are defined.
819 RegionList() : _hd(NULL), _tl(NULL), _sz(0) {}
820 public:
821 void reset() {
822 _hd = NULL;
823 _tl = NULL;
824 _sz = 0;
825 }
826 HeapRegion* hd() { return _hd; }
827 HeapRegion* tl() { return _tl; }
828 size_t sz() { return _sz; }
829 size_t length();
831 bool well_formed() {
832 return
833 ((hd() == NULL && tl() == NULL && sz() == 0)
834 || (hd() != NULL && tl() != NULL && sz() > 0))
835 && (sz() == length());
836 }
837 virtual void insert_before_head(HeapRegion* r);
838 void prepend_list(RegionList* new_list);
839 virtual HeapRegion* pop();
840 void dec_sz() { _sz--; }
841 // Requires that "r" is an element of the list, and is not the tail.
842 void delete_after(HeapRegion* r);
843 };
845 class EmptyNonHRegionList: public RegionList {
846 protected:
847 // Protected constructor because this type is only meaningful
848 // when the _get/_set next functions are defined.
849 EmptyNonHRegionList() : RegionList() {}
851 public:
852 void insert_before_head(HeapRegion* r) {
853 // assert(r->is_empty(), "Better be empty");
854 assert(!r->isHumongous(), "Better not be humongous.");
855 RegionList::insert_before_head(r);
856 }
857 void prepend_list(EmptyNonHRegionList* new_list) {
858 // assert(new_list->hd() == NULL || new_list->hd()->is_empty(),
859 // "Better be empty");
860 assert(new_list->hd() == NULL || !new_list->hd()->isHumongous(),
861 "Better not be humongous.");
862 // assert(new_list->tl() == NULL || new_list->tl()->is_empty(),
863 // "Better be empty");
864 assert(new_list->tl() == NULL || !new_list->tl()->isHumongous(),
865 "Better not be humongous.");
866 RegionList::prepend_list(new_list);
867 }
868 };
870 class UncleanRegionList: public EmptyNonHRegionList {
871 public:
872 HeapRegion* get_next(HeapRegion* hr) {
873 return hr->next_from_unclean_list();
874 }
875 void set_next(HeapRegion* hr, HeapRegion* new_next) {
876 hr->set_next_on_unclean_list(new_next);
877 }
879 UncleanRegionList() : EmptyNonHRegionList() {}
881 void insert_before_head(HeapRegion* r) {
882 assert(!r->is_on_free_list(),
883 "Better not already be on free list");
884 assert(!r->is_on_unclean_list(),
885 "Better not already be on unclean list");
886 r->set_zero_fill_needed();
887 r->set_on_unclean_list(true);
888 EmptyNonHRegionList::insert_before_head(r);
889 }
890 void prepend_list(UncleanRegionList* new_list) {
891 assert(new_list->tl() == NULL || !new_list->tl()->is_on_free_list(),
892 "Better not already be on free list");
893 assert(new_list->tl() == NULL || new_list->tl()->is_on_unclean_list(),
894 "Better already be marked as on unclean list");
895 assert(new_list->hd() == NULL || !new_list->hd()->is_on_free_list(),
896 "Better not already be on free list");
897 assert(new_list->hd() == NULL || new_list->hd()->is_on_unclean_list(),
898 "Better already be marked as on unclean list");
899 EmptyNonHRegionList::prepend_list(new_list);
900 }
901 HeapRegion* pop() {
902 HeapRegion* res = RegionList::pop();
903 if (res != NULL) res->set_on_unclean_list(false);
904 return res;
905 }
906 };
908 // Local Variables: ***
909 // c-indentation-style: gnu ***
910 // End: ***
912 #endif // SERIALGC