1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_VM_GC_G1_HEAPREGION_HPP
26 #define SHARE_VM_GC_G1_HEAPREGION_HPP
27
28 #include "gc/g1/g1AllocationContext.hpp"
29 #include "gc/g1/g1BlockOffsetTable.hpp"
30 #include "gc/g1/heapRegionType.hpp"
31 #include "gc/g1/survRateGroup.hpp"
32 #include "gc/shared/ageTable.hpp"
33 #include "gc/shared/spaceDecorator.hpp"
34 #include "utilities/macros.hpp"
35
36 // A HeapRegion is the smallest piece of a G1CollectedHeap that
37 // can be collected independently.
38
39 // NOTE: Although a HeapRegion is a Space, its
40 // Space::initDirtyCardClosure method must not be called.
41 // The problem is that the existence of this method breaks
42 // the independence of barrier sets from remembered sets.
43 // The solution is to remove this method from the definition
44 // of a Space.
45
46 // Each heap region is self contained. top() and end() can never
47 // be set beyond the end of the region. For humongous objects,
48 // the first region is a StartsHumongous region. If the humongous
49 // object is larger than a heap region, the following regions will
50 // be of type ContinuesHumongous. In this case the top() of the
51 // StartHumongous region and all ContinuesHumongous regions except
52 // the last will point to their own end. For the last ContinuesHumongous
53 // region, top() will equal the object's top.
54
55 class G1CollectedHeap;
56 class HeapRegionRemSet;
57 class HeapRegionRemSetIterator;
58 class HeapRegion;
59 class HeapRegionSetBase;
60 class nmethod;
61
62 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]"
63 #define HR_FORMAT_PARAMS(_hr_) \
64 (_hr_)->hrm_index(), \
65 (_hr_)->get_short_type_str(), \
66 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
67
68 // sentinel value for hrm_index
69 #define G1_NO_HRM_INDEX ((uint) -1)
70
71 // A dirty card to oop closure for heap regions. It
72 // knows how to get the G1 heap and how to use the bitmap
73 // in the concurrent marker used by G1 to filter remembered
74 // sets.
75
76 class HeapRegionDCTOC : public DirtyCardToOopClosure {
77 private:
78 HeapRegion* _hr;
79 G1ParPushHeapRSClosure* _rs_scan;
80 G1CollectedHeap* _g1;
81
82 // Walk the given memory region from bottom to (actual) top
83 // looking for objects and applying the oop closure (_cl) to
84 // them. The base implementation of this treats the area as
85 // blocks, where a block may or may not be an object. Sub-
86 // classes should override this to provide more accurate
87 // or possibly more efficient walking.
88 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
89
90 public:
91 HeapRegionDCTOC(G1CollectedHeap* g1,
92 HeapRegion* hr,
93 G1ParPushHeapRSClosure* cl,
94 CardTableModRefBS::PrecisionStyle precision);
95 };
96
97 // The complicating factor is that BlockOffsetTable diverged
98 // significantly, and we need functionality that is only in the G1 version.
99 // So I copied that code, which led to an alternate G1 version of
100 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
101 // be reconciled, then G1OffsetTableContigSpace could go away.
102
103 // The idea behind time stamps is the following. We want to keep track of
104 // the highest address where it's safe to scan objects for each region.
105 // This is only relevant for current GC alloc regions so we keep a time stamp
106 // per region to determine if the region has been allocated during the current
107 // GC or not. If the time stamp is current we report a scan_top value which
108 // was saved at the end of the previous GC for retained alloc regions and which is
109 // equal to the bottom for all other regions.
110 // There is a race between card scanners and allocating gc workers where we must ensure
111 // that card scanners do not read the memory allocated by the gc workers.
112 // In order to enforce that, we must not return a value of _top which is more recent than the
113 // time stamp. This is due to the fact that a region may become a gc alloc region at
114 // some point after we've read the timestamp value as being < the current time stamp.
115 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
116 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
117 // evacuation pauses between two cleanups, which is _highly_ unlikely.
118 class G1OffsetTableContigSpace: public CompactibleSpace {
119 friend class VMStructs;
120 HeapWord* volatile _top;
121 HeapWord* volatile _scan_top;
122 protected:
123 G1BlockOffsetArrayContigSpace _offsets;
124 Mutex _par_alloc_lock;
125 volatile unsigned _gc_time_stamp;
126 // When we need to retire an allocation region, while other threads
127 // are also concurrently trying to allocate into it, we typically
128 // allocate a dummy object at the end of the region to ensure that
129 // no more allocations can take place in it. However, sometimes we
130 // want to know where the end of the last "real" object we allocated
131 // into the region was and this is what this keeps track.
132 HeapWord* _pre_dummy_top;
133
134 public:
135 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
136 MemRegion mr);
137
138 void set_top(HeapWord* value) { _top = value; }
139 HeapWord* top() const { return _top; }
140
141 protected:
142 // Reset the G1OffsetTableContigSpace.
143 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
144
145 HeapWord* volatile* top_addr() { return &_top; }
146 // Try to allocate at least min_word_size and up to desired_size from this Space.
147 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
148 // space allocated.
149 // This version assumes that all allocation requests to this Space are properly
150 // synchronized.
151 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
152 // Try to allocate at least min_word_size and up to desired_size from this Space.
153 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
154 // space allocated.
155 // This version synchronizes with other calls to par_allocate_impl().
156 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
157
158 public:
159 void reset_after_compaction() { set_top(compaction_top()); }
160
161 size_t used() const { return byte_size(bottom(), top()); }
162 size_t free() const { return byte_size(top(), end()); }
163 bool is_free_block(const HeapWord* p) const { return p >= top(); }
164
165 MemRegion used_region() const { return MemRegion(bottom(), top()); }
166
167 void object_iterate(ObjectClosure* blk);
168 void safe_object_iterate(ObjectClosure* blk);
169
170 void set_bottom(HeapWord* value);
171 void set_end(HeapWord* value);
172
173 void mangle_unused_area() PRODUCT_RETURN;
174 void mangle_unused_area_complete() PRODUCT_RETURN;
175
176 HeapWord* scan_top() const;
177 void record_timestamp();
178 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
179 unsigned get_gc_time_stamp() { return _gc_time_stamp; }
180 void record_retained_region();
181
182 // See the comment above in the declaration of _pre_dummy_top for an
183 // explanation of what it is.
184 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
185 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
186 _pre_dummy_top = pre_dummy_top;
187 }
188 HeapWord* pre_dummy_top() {
189 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
190 }
191 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
192
193 virtual void clear(bool mangle_space);
194
195 HeapWord* block_start(const void* p);
196 HeapWord* block_start_const(const void* p) const;
197
198 // Allocation (return NULL if full). Assumes the caller has established
199 // mutually exclusive access to the space.
200 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
201 // Allocation (return NULL if full). Enforces mutual exclusion internally.
202 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
203
204 virtual HeapWord* allocate(size_t word_size);
205 virtual HeapWord* par_allocate(size_t word_size);
206
207 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
208
209 // MarkSweep support phase3
210 virtual HeapWord* initialize_threshold();
211 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
212
213 virtual void print() const;
214
215 void reset_bot() {
216 _offsets.reset_bot();
217 }
218
219 void print_bot_on(outputStream* out) {
220 _offsets.print_on(out);
221 }
222 };
223
224 class HeapRegion: public G1OffsetTableContigSpace {
225 friend class VMStructs;
226 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
227 template <typename SpaceType>
228 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
229 private:
230
231 // The remembered set for this region.
232 // (Might want to make this "inline" later, to avoid some alloc failure
233 // issues.)
234 HeapRegionRemSet* _rem_set;
235
236 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
237
238 // Auxiliary functions for scan_and_forward support.
239 // See comments for CompactibleSpace for more information.
240 inline HeapWord* scan_limit() const {
241 return top();
242 }
243
244 inline bool scanned_block_is_obj(const HeapWord* addr) const {
245 return true; // Always true, since scan_limit is top
246 }
247
248 inline size_t scanned_block_size(const HeapWord* addr) const {
249 return HeapRegion::block_size(addr); // Avoid virtual call
250 }
251
252 protected:
253 // The index of this region in the heap region sequence.
254 uint _hrm_index;
255
256 AllocationContext_t _allocation_context;
257
258 HeapRegionType _type;
259
260 // For a humongous region, region in which it starts.
261 HeapRegion* _humongous_start_region;
262
263 // True iff an attempt to evacuate an object in the region failed.
264 bool _evacuation_failed;
265
266 // A heap region may be a member one of a number of special subsets, each
267 // represented as linked lists through the field below. Currently, there
268 // is only one set:
269 // The collection set.
270 HeapRegion* _next_in_special_set;
271
272 // next region in the young "generation" region set
273 HeapRegion* _next_young_region;
274
275 // Next region whose cards need cleaning
276 HeapRegion* _next_dirty_cards_region;
277
278 // Fields used by the HeapRegionSetBase class and subclasses.
279 HeapRegion* _next;
280 HeapRegion* _prev;
281 #ifdef ASSERT
282 HeapRegionSetBase* _containing_set;
283 #endif // ASSERT
284
285 // We use concurrent marking to determine the amount of live data
286 // in each heap region.
287 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
288 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
289
290 // The calculated GC efficiency of the region.
291 double _gc_efficiency;
292
293 int _young_index_in_cset;
294 SurvRateGroup* _surv_rate_group;
295 int _age_index;
296
297 // The start of the unmarked area. The unmarked area extends from this
298 // word until the top and/or end of the region, and is the part
299 // of the region for which no marking was done, i.e. objects may
300 // have been allocated in this part since the last mark phase.
301 // "prev" is the top at the start of the last completed marking.
302 // "next" is the top at the start of the in-progress marking (if any.)
303 HeapWord* _prev_top_at_mark_start;
304 HeapWord* _next_top_at_mark_start;
305 // If a collection pause is in progress, this is the top at the start
306 // of that pause.
307
308 void init_top_at_mark_start() {
309 assert(_prev_marked_bytes == 0 &&
310 _next_marked_bytes == 0,
311 "Must be called after zero_marked_bytes.");
312 HeapWord* bot = bottom();
313 _prev_top_at_mark_start = bot;
314 _next_top_at_mark_start = bot;
315 }
316
317 // Cached attributes used in the collection set policy information
318
319 // The RSet length that was added to the total value
320 // for the collection set.
321 size_t _recorded_rs_length;
322
323 // The predicted elapsed time that was added to total value
324 // for the collection set.
325 double _predicted_elapsed_time_ms;
326
327 // The predicted number of bytes to copy that was added to
328 // the total value for the collection set.
329 size_t _predicted_bytes_to_copy;
330
331 public:
332 HeapRegion(uint hrm_index,
333 G1BlockOffsetSharedArray* sharedOffsetArray,
334 MemRegion mr);
335
336 // Initializing the HeapRegion not only resets the data structure, but also
337 // resets the BOT for that heap region.
338 // The default values for clear_space means that we will do the clearing if
339 // there's clearing to be done ourselves. We also always mangle the space.
340 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
341
342 static int LogOfHRGrainBytes;
343 static int LogOfHRGrainWords;
344
345 static size_t GrainBytes;
346 static size_t GrainWords;
347 static size_t CardsPerRegion;
348
349 static size_t align_up_to_region_byte_size(size_t sz) {
350 return (sz + (size_t) GrainBytes - 1) &
351 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
352 }
353
354
355 // Returns whether a field is in the same region as the obj it points to.
356 template <typename T>
357 static bool is_in_same_region(T* p, oop obj) {
358 assert(p != NULL, "p can't be NULL");
359 assert(obj != NULL, "obj can't be NULL");
360 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0;
361 }
362
363 static size_t max_region_size();
364 static size_t min_region_size_in_words();
365
366 // It sets up the heap region size (GrainBytes / GrainWords), as
367 // well as other related fields that are based on the heap region
368 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
369 // CardsPerRegion). All those fields are considered constant
370 // throughout the JVM's execution, therefore they should only be set
371 // up once during initialization time.
372 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
373
374 // All allocated blocks are occupied by objects in a HeapRegion
375 bool block_is_obj(const HeapWord* p) const;
376
377 // Returns the object size for all valid block starts
378 // and the amount of unallocated words if called on top()
379 size_t block_size(const HeapWord* p) const;
380
381 // Override for scan_and_forward support.
382 void prepare_for_compaction(CompactPoint* cp);
383
384 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size);
385 inline HeapWord* allocate_no_bot_updates(size_t word_size);
386 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size);
387
388 // If this region is a member of a HeapRegionManager, the index in that
389 // sequence, otherwise -1.
390 uint hrm_index() const { return _hrm_index; }
391
392 // The number of bytes marked live in the region in the last marking phase.
393 size_t marked_bytes() { return _prev_marked_bytes; }
394 size_t live_bytes() {
395 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
396 }
397
398 // The number of bytes counted in the next marking.
399 size_t next_marked_bytes() { return _next_marked_bytes; }
400 // The number of bytes live wrt the next marking.
401 size_t next_live_bytes() {
402 return
403 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
404 }
405
406 // A lower bound on the amount of garbage bytes in the region.
407 size_t garbage_bytes() {
408 size_t used_at_mark_start_bytes =
409 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
410 return used_at_mark_start_bytes - marked_bytes();
411 }
412
413 // Return the amount of bytes we'll reclaim if we collect this
414 // region. This includes not only the known garbage bytes in the
415 // region but also any unallocated space in it, i.e., [top, end),
416 // since it will also be reclaimed if we collect the region.
417 size_t reclaimable_bytes() {
418 size_t known_live_bytes = live_bytes();
419 assert(known_live_bytes <= capacity(), "sanity");
420 return capacity() - known_live_bytes;
421 }
422
423 // An upper bound on the number of live bytes in the region.
424 size_t max_live_bytes() { return used() - garbage_bytes(); }
425
426 void add_to_marked_bytes(size_t incr_bytes) {
427 _next_marked_bytes = _next_marked_bytes + incr_bytes;
428 }
429
430 void zero_marked_bytes() {
431 _prev_marked_bytes = _next_marked_bytes = 0;
432 }
433
434 const char* get_type_str() const { return _type.get_str(); }
435 const char* get_short_type_str() const { return _type.get_short_str(); }
436
437 bool is_free() const { return _type.is_free(); }
438
439 bool is_young() const { return _type.is_young(); }
440 bool is_eden() const { return _type.is_eden(); }
441 bool is_survivor() const { return _type.is_survivor(); }
442
443 bool is_humongous() const { return _type.is_humongous(); }
444 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
445 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
446
447 bool is_old() const { return _type.is_old(); }
448
449 // A pinned region contains objects which are not moved by garbage collections.
450 // Humongous regions and archive regions are pinned.
451 bool is_pinned() const { return _type.is_pinned(); }
452
453 // An archive region is a pinned region, also tagged as old, which
454 // should not be marked during mark/sweep. This allows the address
455 // space to be shared by JVM instances.
456 bool is_archive() const { return _type.is_archive(); }
457
458 // For a humongous region, region in which it starts.
459 HeapRegion* humongous_start_region() const {
460 return _humongous_start_region;
461 }
462
463 // Makes the current region be a "starts humongous" region, i.e.,
464 // the first region in a series of one or more contiguous regions
465 // that will contain a single "humongous" object.
466 //
467 // obj_top : points to the top of the humongous object.
468 // fill_size : size of the filler object at the end of the region series.
469 void set_starts_humongous(HeapWord* obj_top, size_t fill_size);
470
471 // Makes the current region be a "continues humongous'
472 // region. first_hr is the "start humongous" region of the series
473 // which this region will be part of.
474 void set_continues_humongous(HeapRegion* first_hr);
475
476 // Unsets the humongous-related fields on the region.
477 void clear_humongous();
478
479 // If the region has a remembered set, return a pointer to it.
480 HeapRegionRemSet* rem_set() const {
481 return _rem_set;
482 }
483
484 inline bool in_collection_set() const;
485
486 inline HeapRegion* next_in_collection_set() const;
487 inline void set_next_in_collection_set(HeapRegion* r);
488
489 void set_allocation_context(AllocationContext_t context) {
490 _allocation_context = context;
491 }
492
493 AllocationContext_t allocation_context() const {
494 return _allocation_context;
495 }
496
497 // Methods used by the HeapRegionSetBase class and subclasses.
498
499 // Getter and setter for the next and prev fields used to link regions into
500 // linked lists.
501 HeapRegion* next() { return _next; }
502 HeapRegion* prev() { return _prev; }
503
504 void set_next(HeapRegion* next) { _next = next; }
505 void set_prev(HeapRegion* prev) { _prev = prev; }
506
507 // Every region added to a set is tagged with a reference to that
508 // set. This is used for doing consistency checking to make sure that
509 // the contents of a set are as they should be and it's only
510 // available in non-product builds.
511 #ifdef ASSERT
512 void set_containing_set(HeapRegionSetBase* containing_set) {
513 assert((containing_set == NULL && _containing_set != NULL) ||
514 (containing_set != NULL && _containing_set == NULL),
515 "containing_set: " PTR_FORMAT " "
516 "_containing_set: " PTR_FORMAT,
517 p2i(containing_set), p2i(_containing_set));
518
519 _containing_set = containing_set;
520 }
521
522 HeapRegionSetBase* containing_set() { return _containing_set; }
523 #else // ASSERT
524 void set_containing_set(HeapRegionSetBase* containing_set) { }
525
526 // containing_set() is only used in asserts so there's no reason
527 // to provide a dummy version of it.
528 #endif // ASSERT
529
530 HeapRegion* get_next_young_region() { return _next_young_region; }
531 void set_next_young_region(HeapRegion* hr) {
532 _next_young_region = hr;
533 }
534
535 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
536 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
537 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
538 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
539
540 // Reset HR stuff to default values.
541 void hr_clear(bool par, bool clear_space, bool locked = false);
542 void par_clear();
543
544 // Get the start of the unmarked area in this region.
545 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
546 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
547
548 // Note the start or end of marking. This tells the heap region
549 // that the collector is about to start or has finished (concurrently)
550 // marking the heap.
551
552 // Notify the region that concurrent marking is starting. Initialize
553 // all fields related to the next marking info.
554 inline void note_start_of_marking();
555
556 // Notify the region that concurrent marking has finished. Copy the
557 // (now finalized) next marking info fields into the prev marking
558 // info fields.
559 inline void note_end_of_marking();
560
561 // Notify the region that it will be used as to-space during a GC
562 // and we are about to start copying objects into it.
563 inline void note_start_of_copying(bool during_initial_mark);
564
565 // Notify the region that it ceases being to-space during a GC and
566 // we will not copy objects into it any more.
567 inline void note_end_of_copying(bool during_initial_mark);
568
569 // Notify the region that we are about to start processing
570 // self-forwarded objects during evac failure handling.
571 void note_self_forwarding_removal_start(bool during_initial_mark,
572 bool during_conc_mark);
573
574 // Notify the region that we have finished processing self-forwarded
575 // objects during evac failure handling.
576 void note_self_forwarding_removal_end(bool during_initial_mark,
577 bool during_conc_mark,
578 size_t marked_bytes);
579
580 // Returns "false" iff no object in the region was allocated when the
581 // last mark phase ended.
582 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
583
584 void reset_during_compaction() {
585 assert(is_humongous(),
586 "should only be called for humongous regions");
587
588 zero_marked_bytes();
589 init_top_at_mark_start();
590 }
591
592 void calc_gc_efficiency(void);
593 double gc_efficiency() { return _gc_efficiency;}
594
595 int young_index_in_cset() const { return _young_index_in_cset; }
596 void set_young_index_in_cset(int index) {
597 assert( (index == -1) || is_young(), "pre-condition" );
598 _young_index_in_cset = index;
599 }
600
601 int age_in_surv_rate_group() {
602 assert( _surv_rate_group != NULL, "pre-condition" );
603 assert( _age_index > -1, "pre-condition" );
604 return _surv_rate_group->age_in_group(_age_index);
605 }
606
607 void record_surv_words_in_group(size_t words_survived) {
608 assert( _surv_rate_group != NULL, "pre-condition" );
609 assert( _age_index > -1, "pre-condition" );
610 int age_in_group = age_in_surv_rate_group();
611 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
612 }
613
614 int age_in_surv_rate_group_cond() {
615 if (_surv_rate_group != NULL)
616 return age_in_surv_rate_group();
617 else
618 return -1;
619 }
620
621 SurvRateGroup* surv_rate_group() {
622 return _surv_rate_group;
623 }
624
625 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
626 assert( surv_rate_group != NULL, "pre-condition" );
627 assert( _surv_rate_group == NULL, "pre-condition" );
628 assert( is_young(), "pre-condition" );
629
630 _surv_rate_group = surv_rate_group;
631 _age_index = surv_rate_group->next_age_index();
632 }
633
634 void uninstall_surv_rate_group() {
635 if (_surv_rate_group != NULL) {
636 assert( _age_index > -1, "pre-condition" );
637 assert( is_young(), "pre-condition" );
638
639 _surv_rate_group = NULL;
640 _age_index = -1;
641 } else {
642 assert( _age_index == -1, "pre-condition" );
643 }
644 }
645
646 void set_free() { _type.set_free(); }
647
648 void set_eden() { _type.set_eden(); }
649 void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
650 void set_survivor() { _type.set_survivor(); }
651
652 void set_old() { _type.set_old(); }
653
654 void set_archive() { _type.set_archive(); }
655
656 // Determine if an object has been allocated since the last
657 // mark performed by the collector. This returns true iff the object
658 // is within the unmarked area of the region.
659 bool obj_allocated_since_prev_marking(oop obj) const {
660 return (HeapWord *) obj >= prev_top_at_mark_start();
661 }
662 bool obj_allocated_since_next_marking(oop obj) const {
663 return (HeapWord *) obj >= next_top_at_mark_start();
664 }
665
666 // Returns the "evacuation_failed" property of the region.
667 bool evacuation_failed() { return _evacuation_failed; }
668
669 // Sets the "evacuation_failed" property of the region.
670 void set_evacuation_failed(bool b) {
671 _evacuation_failed = b;
672
673 if (b) {
674 _next_marked_bytes = 0;
675 }
676 }
677
678 // Requires that "mr" be entirely within the region.
679 // Apply "cl->do_object" to all objects that intersect with "mr".
680 // If the iteration encounters an unparseable portion of the region,
681 // or if "cl->abort()" is true after a closure application,
682 // terminate the iteration and return the address of the start of the
683 // subregion that isn't done. (The two can be distinguished by querying
684 // "cl->abort()".) Return of "NULL" indicates that the iteration
685 // completed.
686 HeapWord*
687 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
688
689 // filter_young: if true and the region is a young region then we
690 // skip the iteration.
691 // card_ptr: if not NULL, and we decide that the card is not young
692 // and we iterate over it, we'll clean the card before we start the
693 // iteration.
694 HeapWord*
695 oops_on_card_seq_iterate_careful(MemRegion mr,
696 FilterOutOfRegionClosure* cl,
697 bool filter_young,
698 jbyte* card_ptr);
699
700 size_t recorded_rs_length() const { return _recorded_rs_length; }
701 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
702 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; }
703
704 void set_recorded_rs_length(size_t rs_length) {
705 _recorded_rs_length = rs_length;
706 }
707
708 void set_predicted_elapsed_time_ms(double ms) {
709 _predicted_elapsed_time_ms = ms;
710 }
711
712 void set_predicted_bytes_to_copy(size_t bytes) {
713 _predicted_bytes_to_copy = bytes;
714 }
715
716 virtual CompactibleSpace* next_compaction_space() const;
717
718 virtual void reset_after_compaction();
719
720 // Routines for managing a list of code roots (attached to the
721 // this region's RSet) that point into this heap region.
722 void add_strong_code_root(nmethod* nm);
723 void add_strong_code_root_locked(nmethod* nm);
724 void remove_strong_code_root(nmethod* nm);
725
726 // Applies blk->do_code_blob() to each of the entries in
727 // the strong code roots list for this region
728 void strong_code_roots_do(CodeBlobClosure* blk) const;
729
730 // Verify that the entries on the strong code root list for this
731 // region are live and include at least one pointer into this region.
732 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
733
734 void print() const;
735 void print_on(outputStream* st) const;
736
737 // vo == UsePrevMarking -> use "prev" marking information,
738 // vo == UseNextMarking -> use "next" marking information
739 // vo == UseMarkWord -> use the mark word in the object header
740 //
741 // NOTE: Only the "prev" marking information is guaranteed to be
742 // consistent most of the time, so most calls to this should use
743 // vo == UsePrevMarking.
744 // Currently, there is only one case where this is called with
745 // vo == UseNextMarking, which is to verify the "next" marking
746 // information at the end of remark.
747 // Currently there is only one place where this is called with
748 // vo == UseMarkWord, which is to verify the marking during a
749 // full GC.
750 void verify(VerifyOption vo, bool *failures) const;
751
752 // Override; it uses the "prev" marking information
753 virtual void verify() const;
754 };
755
756 // HeapRegionClosure is used for iterating over regions.
757 // Terminates the iteration when the "doHeapRegion" method returns "true".
758 class HeapRegionClosure : public StackObj {
759 friend class HeapRegionManager;
760 friend class G1CollectedHeap;
761
762 bool _complete;
763 void incomplete() { _complete = false; }
764
765 public:
766 HeapRegionClosure(): _complete(true) {}
767
768 // Typically called on each region until it returns true.
769 virtual bool doHeapRegion(HeapRegion* r) = 0;
770
771 // True after iteration if the closure was applied to all heap regions
772 // and returned "false" in all cases.
773 bool complete() { return _complete; }
774 };
775
776 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP