1 /*
2 * Copyright (c) 2001, 2014, 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
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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 *
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23 */
24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
27
28 #include "gc_implementation/g1/g1AllocationContext.hpp"
29 #include "gc_implementation/g1/g1BlockOffsetTable.hpp"
30 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
31 #include "gc_implementation/g1/heapRegionType.hpp"
32 #include "gc_implementation/g1/survRateGroup.hpp"
33 #include "gc_implementation/shared/ageTable.hpp"
34 #include "gc_implementation/shared/spaceDecorator.hpp"
35 #include "memory/space.inline.hpp"
36 #include "memory/watermark.hpp"
37 #include "utilities/macros.hpp"
38
39 // A HeapRegion is the smallest piece of a G1CollectedHeap that
40 // can be collected independently.
41
42 // NOTE: Although a HeapRegion is a Space, its
43 // Space::initDirtyCardClosure method must not be called.
44 // The problem is that the existence of this method breaks
45 // the independence of barrier sets from remembered sets.
46 // The solution is to remove this method from the definition
47 // of a Space.
48
49 class HeapRegionRemSet;
50 class HeapRegionRemSetIterator;
51 class HeapRegion;
52 class HeapRegionSetBase;
53 class nmethod;
54
55 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
56 #define HR_FORMAT_PARAMS(_hr_) \
57 (_hr_)->hrm_index(), \
58 (_hr_)->get_short_type_str(), \
59 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
60
61 // sentinel value for hrm_index
62 #define G1_NO_HRM_INDEX ((uint) -1)
63
64 // A dirty card to oop closure for heap regions. It
65 // knows how to get the G1 heap and how to use the bitmap
66 // in the concurrent marker used by G1 to filter remembered
67 // sets.
68
69 class HeapRegionDCTOC : public DirtyCardToOopClosure {
70 private:
71 HeapRegion* _hr;
72 G1ParPushHeapRSClosure* _rs_scan;
73 G1CollectedHeap* _g1;
74
75 // Walk the given memory region from bottom to (actual) top
76 // looking for objects and applying the oop closure (_cl) to
77 // them. The base implementation of this treats the area as
78 // blocks, where a block may or may not be an object. Sub-
79 // classes should override this to provide more accurate
80 // or possibly more efficient walking.
81 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
82
83 public:
84 HeapRegionDCTOC(G1CollectedHeap* g1,
85 HeapRegion* hr, G1ParPushHeapRSClosure* cl,
86 CardTableModRefBS::PrecisionStyle precision);
87 };
88
89 // The complicating factor is that BlockOffsetTable diverged
90 // significantly, and we need functionality that is only in the G1 version.
91 // So I copied that code, which led to an alternate G1 version of
92 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
93 // be reconciled, then G1OffsetTableContigSpace could go away.
94
95 // The idea behind time stamps is the following. We want to keep track of
96 // the highest address where it's safe to scan objects for each region.
97 // This is only relevant for current GC alloc regions so we keep a time stamp
98 // per region to determine if the region has been allocated during the current
99 // GC or not. If the time stamp is current we report a scan_top value which
100 // was saved at the end of the previous GC for retained alloc regions and which is
101 // equal to the bottom for all other regions.
102 // There is a race between card scanners and allocating gc workers where we must ensure
103 // that card scanners do not read the memory allocated by the gc workers.
104 // In order to enforce that, we must not return a value of _top which is more recent than the
105 // time stamp. This is due to the fact that a region may become a gc alloc region at
106 // some point after we've read the timestamp value as being < the current time stamp.
107 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
108 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
109 // evacuation pauses between two cleanups, which is _highly_ unlikely.
110 class G1OffsetTableContigSpace: public CompactibleSpace {
111 friend class VMStructs;
112 HeapWord* _top;
113 HeapWord* volatile _scan_top;
114 protected:
115 G1BlockOffsetArrayContigSpace _offsets;
116 Mutex _par_alloc_lock;
117 volatile unsigned _gc_time_stamp;
118 // When we need to retire an allocation region, while other threads
119 // are also concurrently trying to allocate into it, we typically
120 // allocate a dummy object at the end of the region to ensure that
121 // no more allocations can take place in it. However, sometimes we
122 // want to know where the end of the last "real" object we allocated
123 // into the region was and this is what this keeps track.
124 HeapWord* _pre_dummy_top;
125
126 public:
127 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
128 MemRegion mr);
129
130 void set_top(HeapWord* value) { _top = value; }
131 HeapWord* top() const { return _top; }
132
133 protected:
134 // Reset the G1OffsetTableContigSpace.
135 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
136
137 HeapWord** top_addr() { return &_top; }
138 // Allocation helpers (return NULL if full).
139 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
140 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
141
142 public:
143 void reset_after_compaction() { set_top(compaction_top()); }
144
145 size_t used() const { return byte_size(bottom(), top()); }
146 size_t free() const { return byte_size(top(), end()); }
147 bool is_free_block(const HeapWord* p) const { return p >= top(); }
148
149 MemRegion used_region() const { return MemRegion(bottom(), top()); }
150
151 void object_iterate(ObjectClosure* blk);
152 void safe_object_iterate(ObjectClosure* blk);
153
154 void set_bottom(HeapWord* value);
155 void set_end(HeapWord* value);
156
157 HeapWord* scan_top() const;
158 void record_timestamp();
159 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
160 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
161 void record_retained_region();
162
163 // See the comment above in the declaration of _pre_dummy_top for an
164 // explanation of what it is.
165 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
166 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
167 _pre_dummy_top = pre_dummy_top;
168 }
169 HeapWord* pre_dummy_top() {
170 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
171 }
172 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
173
174 virtual void clear(bool mangle_space);
175
176 HeapWord* block_start(const void* p);
177 HeapWord* block_start_const(const void* p) const;
178
179 // Add offset table update.
180 virtual HeapWord* allocate(size_t word_size);
181 HeapWord* par_allocate(size_t word_size);
182
183 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
184
185 // MarkSweep support phase3
186 virtual HeapWord* initialize_threshold();
187 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
188
189 virtual void print() const;
190
191 void reset_bot() {
192 _offsets.reset_bot();
193 }
194
195 void print_bot_on(outputStream* out) {
196 _offsets.print_on(out);
197 }
198 };
199
200 class HeapRegion: public G1OffsetTableContigSpace {
201 friend class VMStructs;
202 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
203 template <typename SpaceType>
204 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
205 private:
206
207 // The remembered set for this region.
208 // (Might want to make this "inline" later, to avoid some alloc failure
209 // issues.)
210 HeapRegionRemSet* _rem_set;
211
212 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
213
214 // Auxiliary functions for scan_and_forward support.
215 // See comments for CompactibleSpace for more information.
216 inline HeapWord* scan_limit() const {
217 return top();
218 }
219
220 inline bool scanned_block_is_obj(const HeapWord* addr) const {
221 return true; // Always true, since scan_limit is top
222 }
223
224 inline size_t scanned_block_size(const HeapWord* addr) const {
225 return HeapRegion::block_size(addr); // Avoid virtual call
226 }
227
228 protected:
229 // The index of this region in the heap region sequence.
230 uint _hrm_index;
231
232 AllocationContext_t _allocation_context;
233
234 HeapRegionType _type;
235
236 // For a humongous region, region in which it starts.
237 HeapRegion* _humongous_start_region;
238 // True iff the region is in current collection_set.
239 bool _in_collection_set;
240
241 // True iff an attempt to evacuate an object in the region failed.
242 bool _evacuation_failed;
243
244 // A heap region may be a member one of a number of special subsets, each
245 // represented as linked lists through the field below. Currently, there
246 // is only one set:
247 // The collection set.
248 HeapRegion* _next_in_special_set;
249
250 // next region in the young "generation" region set
251 HeapRegion* _next_young_region;
252
253 // Next region whose cards need cleaning
254 HeapRegion* _next_dirty_cards_region;
255
256 // Fields used by the HeapRegionSetBase class and subclasses.
257 HeapRegion* _next;
258 HeapRegion* _prev;
259 #ifdef ASSERT
260 HeapRegionSetBase* _containing_set;
261 #endif // ASSERT
262
263 // We use concurrent marking to determine the amount of live data
264 // in each heap region.
265 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
266 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
267
268 // The calculated GC efficiency of the region.
269 double _gc_efficiency;
270
271 int _young_index_in_cset;
272 SurvRateGroup* _surv_rate_group;
273 int _age_index;
274
275 // The start of the unmarked area. The unmarked area extends from this
276 // word until the top and/or end of the region, and is the part
277 // of the region for which no marking was done, i.e. objects may
278 // have been allocated in this part since the last mark phase.
279 // "prev" is the top at the start of the last completed marking.
280 // "next" is the top at the start of the in-progress marking (if any.)
281 HeapWord* _prev_top_at_mark_start;
282 HeapWord* _next_top_at_mark_start;
283 // If a collection pause is in progress, this is the top at the start
284 // of that pause.
285
286 void init_top_at_mark_start() {
287 assert(_prev_marked_bytes == 0 &&
288 _next_marked_bytes == 0,
289 "Must be called after zero_marked_bytes.");
290 HeapWord* bot = bottom();
291 _prev_top_at_mark_start = bot;
292 _next_top_at_mark_start = bot;
293 }
294
295 // Cached attributes used in the collection set policy information
296
297 // The RSet length that was added to the total value
298 // for the collection set.
299 size_t _recorded_rs_length;
300
301 // The predicted elapsed time that was added to total value
302 // for the collection set.
303 double _predicted_elapsed_time_ms;
304
305 // The predicted number of bytes to copy that was added to
306 // the total value for the collection set.
307 size_t _predicted_bytes_to_copy;
308
309 public:
310 HeapRegion(uint hrm_index,
311 G1BlockOffsetSharedArray* sharedOffsetArray,
312 MemRegion mr);
313
314 // Initializing the HeapRegion not only resets the data structure, but also
315 // resets the BOT for that heap region.
316 // The default values for clear_space means that we will do the clearing if
317 // there's clearing to be done ourselves. We also always mangle the space.
318 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
319
320 static int LogOfHRGrainBytes;
321 static int LogOfHRGrainWords;
322
323 static size_t GrainBytes;
324 static size_t GrainWords;
325 static size_t CardsPerRegion;
326
327 static size_t align_up_to_region_byte_size(size_t sz) {
328 return (sz + (size_t) GrainBytes - 1) &
329 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
330 }
331
332 static size_t max_region_size();
333
334 // It sets up the heap region size (GrainBytes / GrainWords), as
335 // well as other related fields that are based on the heap region
336 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
337 // CardsPerRegion). All those fields are considered constant
338 // throughout the JVM's execution, therefore they should only be set
339 // up once during initialization time.
340 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
341
342 // All allocated blocks are occupied by objects in a HeapRegion
343 bool block_is_obj(const HeapWord* p) const;
344
345 // Returns the object size for all valid block starts
346 // and the amount of unallocated words if called on top()
347 size_t block_size(const HeapWord* p) const;
348
349 // Override for scan_and_forward support.
350 void prepare_for_compaction(CompactPoint* cp);
351
352 inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
353 inline HeapWord* allocate_no_bot_updates(size_t word_size);
354
355 // If this region is a member of a HeapRegionManager, the index in that
356 // sequence, otherwise -1.
357 uint hrm_index() const { return _hrm_index; }
358
359 // The number of bytes marked live in the region in the last marking phase.
360 size_t marked_bytes() { return _prev_marked_bytes; }
361 size_t live_bytes() {
362 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
363 }
364
365 // The number of bytes counted in the next marking.
366 size_t next_marked_bytes() { return _next_marked_bytes; }
367 // The number of bytes live wrt the next marking.
368 size_t next_live_bytes() {
369 return
370 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
371 }
372
373 // A lower bound on the amount of garbage bytes in the region.
374 size_t garbage_bytes() {
375 size_t used_at_mark_start_bytes =
376 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
377 assert(used_at_mark_start_bytes >= marked_bytes(),
378 "Can't mark more than we have.");
379 return used_at_mark_start_bytes - marked_bytes();
380 }
381
382 // Return the amount of bytes we'll reclaim if we collect this
383 // region. This includes not only the known garbage bytes in the
384 // region but also any unallocated space in it, i.e., [top, end),
385 // since it will also be reclaimed if we collect the region.
386 size_t reclaimable_bytes() {
387 size_t known_live_bytes = live_bytes();
388 assert(known_live_bytes <= capacity(), "sanity");
389 return capacity() - known_live_bytes;
390 }
391
392 // An upper bound on the number of live bytes in the region.
393 size_t max_live_bytes() { return used() - garbage_bytes(); }
394
395 void add_to_marked_bytes(size_t incr_bytes) {
396 _next_marked_bytes = _next_marked_bytes + incr_bytes;
397 assert(_next_marked_bytes <= used(), "invariant" );
398 }
399
400 void zero_marked_bytes() {
401 _prev_marked_bytes = _next_marked_bytes = 0;
402 }
403
404 const char* get_type_str() const { return _type.get_str(); }
405 const char* get_short_type_str() const { return _type.get_short_str(); }
406
407 bool is_free() const { return _type.is_free(); }
408
409 bool is_young() const { return _type.is_young(); }
410 bool is_eden() const { return _type.is_eden(); }
411 bool is_survivor() const { return _type.is_survivor(); }
412
413 bool is_humongous() const { return _type.is_humongous(); }
414 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
415 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
416
417 bool is_old() const { return _type.is_old(); }
418
419 // For a humongous region, region in which it starts.
420 HeapRegion* humongous_start_region() const {
421 return _humongous_start_region;
422 }
423
424 // Return the number of distinct regions that are covered by this region:
425 // 1 if the region is not humongous, >= 1 if the region is humongous.
426 uint region_num() const {
427 if (!is_humongous()) {
428 return 1U;
429 } else {
430 assert(is_starts_humongous(), "doesn't make sense on HC regions");
431 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
432 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
433 }
434 }
435
436 // Return the index + 1 of the last HC regions that's associated
437 // with this HS region.
438 uint last_hc_index() const {
439 assert(is_starts_humongous(), "don't call this otherwise");
440 return hrm_index() + region_num();
441 }
442
443 // Same as Space::is_in_reserved, but will use the original size of the region.
444 // The original size is different only for start humongous regions. They get
445 // their _end set up to be the end of the last continues region of the
446 // corresponding humongous object.
447 bool is_in_reserved_raw(const void* p) const {
448 return _bottom <= p && p < orig_end();
449 }
450
451 // Makes the current region be a "starts humongous" region, i.e.,
452 // the first region in a series of one or more contiguous regions
453 // that will contain a single "humongous" object. The two parameters
454 // are as follows:
455 //
456 // new_top : The new value of the top field of this region which
457 // points to the end of the humongous object that's being
458 // allocated. If there is more than one region in the series, top
459 // will lie beyond this region's original end field and on the last
460 // region in the series.
461 //
462 // new_end : The new value of the end field of this region which
463 // points to the end of the last region in the series. If there is
464 // one region in the series (namely: this one) end will be the same
465 // as the original end of this region.
466 //
467 // Updating top and end as described above makes this region look as
468 // if it spans the entire space taken up by all the regions in the
469 // series and an single allocation moved its top to new_top. This
470 // ensures that the space (capacity / allocated) taken up by all
471 // humongous regions can be calculated by just looking at the
472 // "starts humongous" regions and by ignoring the "continues
473 // humongous" regions.
474 void set_starts_humongous(HeapWord* new_top, HeapWord* new_end);
475
476 // Makes the current region be a "continues humongous'
477 // region. first_hr is the "start humongous" region of the series
478 // which this region will be part of.
479 void set_continues_humongous(HeapRegion* first_hr);
480
481 // Unsets the humongous-related fields on the region.
482 void clear_humongous();
483
484 // If the region has a remembered set, return a pointer to it.
485 HeapRegionRemSet* rem_set() const {
486 return _rem_set;
487 }
488
489 // True iff the region is in current collection_set.
490 bool in_collection_set() const {
491 return _in_collection_set;
492 }
493 void set_in_collection_set(bool b) {
494 _in_collection_set = b;
495 }
496 HeapRegion* next_in_collection_set() {
497 assert(in_collection_set(), "should only invoke on member of CS.");
498 assert(_next_in_special_set == NULL ||
499 _next_in_special_set->in_collection_set(),
500 "Malformed CS.");
501 return _next_in_special_set;
502 }
503 void set_next_in_collection_set(HeapRegion* r) {
504 assert(in_collection_set(), "should only invoke on member of CS.");
505 assert(r == NULL || r->in_collection_set(), "Malformed CS.");
506 _next_in_special_set = r;
507 }
508
509 void set_allocation_context(AllocationContext_t context) {
510 _allocation_context = context;
511 }
512
513 AllocationContext_t allocation_context() const {
514 return _allocation_context;
515 }
516
517 // Methods used by the HeapRegionSetBase class and subclasses.
518
519 // Getter and setter for the next and prev fields used to link regions into
520 // linked lists.
521 HeapRegion* next() { return _next; }
522 HeapRegion* prev() { return _prev; }
523
524 void set_next(HeapRegion* next) { _next = next; }
525 void set_prev(HeapRegion* prev) { _prev = prev; }
526
527 // Every region added to a set is tagged with a reference to that
528 // set. This is used for doing consistency checking to make sure that
529 // the contents of a set are as they should be and it's only
530 // available in non-product builds.
531 #ifdef ASSERT
532 void set_containing_set(HeapRegionSetBase* containing_set) {
533 assert((containing_set == NULL && _containing_set != NULL) ||
534 (containing_set != NULL && _containing_set == NULL),
535 err_msg("containing_set: "PTR_FORMAT" "
536 "_containing_set: "PTR_FORMAT,
537 p2i(containing_set), p2i(_containing_set)));
538
539 _containing_set = containing_set;
540 }
541
542 HeapRegionSetBase* containing_set() { return _containing_set; }
543 #else // ASSERT
544 void set_containing_set(HeapRegionSetBase* containing_set) { }
545
546 // containing_set() is only used in asserts so there's no reason
547 // to provide a dummy version of it.
548 #endif // ASSERT
549
550 HeapRegion* get_next_young_region() { return _next_young_region; }
551 void set_next_young_region(HeapRegion* hr) {
552 _next_young_region = hr;
553 }
554
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; }
559
560 // For the start region of a humongous sequence, it's original end().
561 HeapWord* orig_end() const { return _bottom + GrainWords; }
562
563 // Reset HR stuff to default values.
564 void hr_clear(bool par, bool clear_space, bool locked = false);
565 void par_clear();
566
567 // Get the start of the unmarked area in this region.
568 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
569 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
570
571 // Note the start or end of marking. This tells the heap region
572 // that the collector is about to start or has finished (concurrently)
573 // marking the heap.
574
575 // Notify the region that concurrent marking is starting. Initialize
576 // all fields related to the next marking info.
577 inline void note_start_of_marking();
578
579 // Notify the region that concurrent marking has finished. Copy the
580 // (now finalized) next marking info fields into the prev marking
581 // info fields.
582 inline void note_end_of_marking();
583
584 // Notify the region that it will be used as to-space during a GC
585 // and we are about to start copying objects into it.
586 inline void note_start_of_copying(bool during_initial_mark);
587
588 // Notify the region that it ceases being to-space during a GC and
589 // we will not copy objects into it any more.
590 inline void note_end_of_copying(bool during_initial_mark);
591
592 // Notify the region that we are about to start processing
593 // self-forwarded objects during evac failure handling.
594 void note_self_forwarding_removal_start(bool during_initial_mark,
595 bool during_conc_mark);
596
597 // Notify the region that we have finished processing self-forwarded
598 // objects during evac failure handling.
599 void note_self_forwarding_removal_end(bool during_initial_mark,
600 bool during_conc_mark,
601 size_t marked_bytes);
602
603 // Returns "false" iff no object in the region was allocated when the
604 // last mark phase ended.
605 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
606
607 void reset_during_compaction() {
608 assert(is_starts_humongous(),
609 "should only be called for starts humongous regions");
610
611 zero_marked_bytes();
612 init_top_at_mark_start();
613 }
614
615 void calc_gc_efficiency(void);
616 double gc_efficiency() { return _gc_efficiency;}
617
618 int young_index_in_cset() const { return _young_index_in_cset; }
619 void set_young_index_in_cset(int index) {
620 assert( (index == -1) || is_young(), "pre-condition" );
621 _young_index_in_cset = index;
622 }
623
624 int age_in_surv_rate_group() {
625 assert( _surv_rate_group != NULL, "pre-condition" );
626 assert( _age_index > -1, "pre-condition" );
627 return _surv_rate_group->age_in_group(_age_index);
628 }
629
630 void record_surv_words_in_group(size_t words_survived) {
631 assert( _surv_rate_group != NULL, "pre-condition" );
632 assert( _age_index > -1, "pre-condition" );
633 int age_in_group = age_in_surv_rate_group();
634 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
635 }
636
637 int age_in_surv_rate_group_cond() {
638 if (_surv_rate_group != NULL)
639 return age_in_surv_rate_group();
640 else
641 return -1;
642 }
643
644 SurvRateGroup* surv_rate_group() {
645 return _surv_rate_group;
646 }
647
648 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
649 assert( surv_rate_group != NULL, "pre-condition" );
650 assert( _surv_rate_group == NULL, "pre-condition" );
651 assert( is_young(), "pre-condition" );
652
653 _surv_rate_group = surv_rate_group;
654 _age_index = surv_rate_group->next_age_index();
655 }
656
657 void uninstall_surv_rate_group() {
658 if (_surv_rate_group != NULL) {
659 assert( _age_index > -1, "pre-condition" );
660 assert( is_young(), "pre-condition" );
661
662 _surv_rate_group = NULL;
663 _age_index = -1;
664 } else {
665 assert( _age_index == -1, "pre-condition" );
666 }
667 }
668
669 void set_free() { _type.set_free(); }
670
671 void set_eden() { _type.set_eden(); }
672 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
673 void set_survivor() { _type.set_survivor(); }
674
675 void set_old() { _type.set_old(); }
676
677 // Determine if an object has been allocated since the last
678 // mark performed by the collector. This returns true iff the object
679 // is within the unmarked area of the region.
680 bool obj_allocated_since_prev_marking(oop obj) const {
681 return (HeapWord *) obj >= prev_top_at_mark_start();
682 }
683 bool obj_allocated_since_next_marking(oop obj) const {
684 return (HeapWord *) obj >= next_top_at_mark_start();
685 }
686
687 // Returns the "evacuation_failed" property of the region.
688 bool evacuation_failed() { return _evacuation_failed; }
689
690 // Sets the "evacuation_failed" property of the region.
691 void set_evacuation_failed(bool b) {
692 _evacuation_failed = b;
693
694 if (b) {
695 _next_marked_bytes = 0;
696 }
697 }
698
699 // Requires that "mr" be entirely within the region.
700 // Apply "cl->do_object" to all objects that intersect with "mr".
701 // If the iteration encounters an unparseable portion of the region,
702 // or if "cl->abort()" is true after a closure application,
703 // terminate the iteration and return the address of the start of the
704 // subregion that isn't done. (The two can be distinguished by querying
705 // "cl->abort()".) Return of "NULL" indicates that the iteration
706 // completed.
707 HeapWord*
708 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
709
710 // filter_young: if true and the region is a young region then we
711 // skip the iteration.
712 // card_ptr: if not NULL, and we decide that the card is not young
713 // and we iterate over it, we'll clean the card before we start the
714 // iteration.
715 HeapWord*
716 oops_on_card_seq_iterate_careful(MemRegion mr,
717 FilterOutOfRegionClosure* cl,
718 bool filter_young,
719 jbyte* card_ptr);
720
721 size_t recorded_rs_length() const { return _recorded_rs_length; }
722 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
723 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
724
725 void set_recorded_rs_length(size_t rs_length) {
726 _recorded_rs_length = rs_length;
727 }
728
729 void set_predicted_elapsed_time_ms(double ms) {
730 _predicted_elapsed_time_ms = ms;
731 }
732
733 void set_predicted_bytes_to_copy(size_t bytes) {
734 _predicted_bytes_to_copy = bytes;
735 }
736
737 virtual CompactibleSpace* next_compaction_space() const;
738
739 virtual void reset_after_compaction();
740
741 // Routines for managing a list of code roots (attached to the
742 // this region's RSet) that point into this heap region.
743 void add_strong_code_root(nmethod* nm);
744 void add_strong_code_root_locked(nmethod* nm);
745 void remove_strong_code_root(nmethod* nm);
746
747 // Applies blk->do_code_blob() to each of the entries in
748 // the strong code roots list for this region
749 void strong_code_roots_do(CodeBlobClosure* blk) const;
750
751 // Verify that the entries on the strong code root list for this
752 // region are live and include at least one pointer into this region.
753 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
754
755 void print() const;
756 void print_on(outputStream* st) const;
757
758 // vo == UsePrevMarking -> use "prev" marking information,
759 // vo == UseNextMarking -> use "next" marking information
760 // vo == UseMarkWord -> use the mark word in the object header
761 //
762 // NOTE: Only the "prev" marking information is guaranteed to be
763 // consistent most of the time, so most calls to this should use
764 // vo == UsePrevMarking.
765 // Currently, there is only one case where this is called with
766 // vo == UseNextMarking, which is to verify the "next" marking
767 // information at the end of remark.
768 // Currently there is only one place where this is called with
769 // vo == UseMarkWord, which is to verify the marking during a
770 // full GC.
771 void verify(VerifyOption vo, bool *failures) const;
772
773 // Override; it uses the "prev" marking information
774 virtual void verify() const;
775 };
776
777 // HeapRegionClosure is used for iterating over regions.
778 // Terminates the iteration when the "doHeapRegion" method returns "true".
779 class HeapRegionClosure : public StackObj {
780 friend class HeapRegionManager;
781 friend class G1CollectedHeap;
782
783 bool _complete;
784 void incomplete() { _complete = false; }
785
786 public:
787 HeapRegionClosure(): _complete(true) {}
788
789 // Typically called on each region until it returns true.
790 virtual bool doHeapRegion(HeapRegion* r) = 0;
791
792 // True after iteration if the closure was applied to all heap regions
793 // and returned "false" in all cases.
794 bool complete() { return _complete; }
795 };
796
797 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP