1 /*
2 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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24
25 #ifndef SHARE_GC_G1_HEAPREGION_HPP
26 #define SHARE_GC_G1_HEAPREGION_HPP
27
28 #include "gc/g1/g1BlockOffsetTable.hpp"
29 #include "gc/g1/g1HeapRegionTraceType.hpp"
30 #include "gc/g1/heapRegionTracer.hpp"
31 #include "gc/g1/heapRegionType.hpp"
32 #include "gc/g1/survRateGroup.hpp"
33 #include "gc/shared/ageTable.hpp"
34 #include "gc/shared/spaceDecorator.hpp"
35 #include "gc/shared/verifyOption.hpp"
36 #include "runtime/mutex.hpp"
37 #include "utilities/macros.hpp"
38
39 class G1CollectedHeap;
40 class G1CMBitMap;
41 class HeapRegionRemSet;
42 class HeapRegion;
43 class HeapRegionSetBase;
44 class nmethod;
45
46 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]"
47 #define HR_FORMAT_PARAMS(_hr_) \
48 (_hr_)->hrm_index(), \
49 (_hr_)->get_short_type_str(), \
50 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
51
52 // sentinel value for hrm_index
53 #define G1_NO_HRM_INDEX ((uint) -1)
54
55 // A HeapRegion is the smallest piece of a G1CollectedHeap that
56 // can be collected independently.
57
58 // Each heap region is self contained. top() and end() can never
59 // be set beyond the end of the region. For humongous objects,
60 // the first region is a StartsHumongous region. If the humongous
61 // object is larger than a heap region, the following regions will
62 // be of type ContinuesHumongous. In this case the top() of the
63 // StartHumongous region and all ContinuesHumongous regions except
64 // the last will point to their own end. The last ContinuesHumongous
65 // region may have top() equal the end of object if there isn't
66 // room for filler objects to pad out to the end of the region.
67 class HeapRegion : public CHeapObj<mtGC> {
68 friend class VMStructs;
69
70 HeapWord* _bottom;
71 HeapWord* _end;
72
73 HeapWord* volatile _top;
74 HeapWord* _compaction_top;
75
76 G1BlockOffsetTablePart _bot_part;
77 Mutex _par_alloc_lock;
78 // When we need to retire an allocation region, while other threads
79 // are also concurrently trying to allocate into it, we typically
80 // allocate a dummy object at the end of the region to ensure that
81 // no more allocations can take place in it. However, sometimes we
82 // want to know where the end of the last "real" object we allocated
83 // into the region was and this is what this keeps track.
84 HeapWord* _pre_dummy_top;
85
86 public:
87 void set_bottom(HeapWord* value) { _bottom = value; }
88 HeapWord* bottom() const { return _bottom; }
89
90 void set_end(HeapWord* value) { _end = value; }
91 HeapWord* end() const { return _end; }
92
93 void set_compaction_top(HeapWord* compaction_top) { _compaction_top = compaction_top; }
94 HeapWord* compaction_top() const { return _compaction_top; }
95
96 void set_top(HeapWord* value) { _top = value; }
97 HeapWord* top() const { return _top; }
98
99 // Returns true iff the given the heap region contains the
100 // given address as part of an allocated object. This may
101 // be a potentially, so we restrict its use to assertion checks only.
102 bool is_in(const void* p) const {
103 return is_in_reserved(p);
104 }
105 bool is_in(oop obj) const {
106 return is_in((void*)obj);
107 }
108 // Returns true iff the given reserved memory of the space contains the
109 // given address.
110 bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; }
111
112 size_t capacity() const { return byte_size(bottom(), end()); }
113 size_t used() const { return byte_size(bottom(), top()); }
114 size_t free() const { return byte_size(top(), end()); }
115
116 bool is_empty() const { return used() == 0; }
117
118 private:
119 void reset_after_compaction() { set_top(compaction_top()); }
120
121 // Try to allocate at least min_word_size and up to desired_size from this region.
122 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
123 // space allocated.
124 // This version assumes that all allocation requests to this HeapRegion are properly
125 // synchronized.
126 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
127 // Try to allocate at least min_word_size and up to desired_size from this HeapRegion.
128 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
129 // space allocated.
130 // This version synchronizes with other calls to par_allocate_impl().
131 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
132
133 void mangle_unused_area() PRODUCT_RETURN;
134
135 public:
136 void object_iterate(ObjectClosure* blk);
137
138 // See the comment above in the declaration of _pre_dummy_top for an
139 // explanation of what it is.
140 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
141 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
142 _pre_dummy_top = pre_dummy_top;
143 }
144
145 HeapWord* pre_dummy_top() {
146 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
147 }
148 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
149
150 void clear(bool mangle_space);
151
152 HeapWord* block_start(const void* p);
153 HeapWord* block_start_const(const void* p) const;
154
155 // Allocation (return NULL if full). Assumes the caller has established
156 // mutually exclusive access to the HeapRegion.
157 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
158 // Allocation (return NULL if full). Enforces mutual exclusion internally.
159 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
160
161 HeapWord* allocate(size_t word_size);
162 HeapWord* par_allocate(size_t word_size);
163
164 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
165
166 // MarkSweep support phase3
167 HeapWord* initialize_threshold();
168 HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
169
170 void reset_bot() {
171 _bot_part.reset_bot();
172 }
173
174 void print_bot_on(outputStream* out) {
175 _bot_part.print_on(out);
176 }
177
178 private:
179 // The remembered set for this region.
180 HeapRegionRemSet* _rem_set;
181
182 void report_region_type_change(G1HeapRegionTraceType::Type to);
183
184 // Returns whether the given object address refers to a dead object, and either the
185 // size of the object (if live) or the size of the block (if dead) in size.
186 // May
187 // - only called with obj < top()
188 // - not called on humongous objects or archive regions
189 inline bool is_obj_dead_with_size(const oop obj, const G1CMBitMap* const prev_bitmap, size_t* size) const;
190
191 // The index of this region in the heap region sequence.
192 uint _hrm_index;
193
194 HeapRegionType _type;
195
196 // For a humongous region, region in which it starts.
197 HeapRegion* _humongous_start_region;
198
199 // True iff an attempt to evacuate an object in the region failed.
200 bool _evacuation_failed;
201
202 // Fields used by the HeapRegionSetBase class and subclasses.
203 HeapRegion* _next;
204 HeapRegion* _prev;
205 #ifdef ASSERT
206 HeapRegionSetBase* _containing_set;
207 #endif // ASSERT
208
209 // We use concurrent marking to determine the amount of live data
210 // in each heap region.
211 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
212 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
213
214 // The calculated GC efficiency of the region.
215 double _gc_efficiency;
216
217 static const uint InvalidCSetIndex = UINT_MAX;
218
219 // The index in the optional regions array, if this region
220 // is considered optional during a mixed collections.
221 uint _index_in_opt_cset;
222
223 // Data for young region survivor prediction.
224 uint _young_index_in_cset;
225 SurvRateGroup* _surv_rate_group;
226 int _age_index;
227
228 // The start of the unmarked area. The unmarked area extends from this
229 // word until the top and/or end of the region, and is the part
230 // of the region for which no marking was done, i.e. objects may
231 // have been allocated in this part since the last mark phase.
232 // "prev" is the top at the start of the last completed marking.
233 // "next" is the top at the start of the in-progress marking (if any.)
234 HeapWord* _prev_top_at_mark_start;
235 HeapWord* _next_top_at_mark_start;
236
237 void init_top_at_mark_start() {
238 assert(_prev_marked_bytes == 0 &&
239 _next_marked_bytes == 0,
240 "Must be called after zero_marked_bytes.");
241 HeapWord* bot = bottom();
242 _prev_top_at_mark_start = bot;
243 _next_top_at_mark_start = bot;
244 }
245
246 // Cached attributes used in the collection set policy information
247
248 // The RSet length that was added to the total value
249 // for the collection set.
250 size_t _recorded_rs_length;
251
252 // The predicted elapsed time that was added to total value
253 // for the collection set.
254 double _predicted_elapsed_time_ms;
255
256 // Iterate over the references covered by the given MemRegion in a humongous
257 // object and apply the given closure to them.
258 // Humongous objects are allocated directly in the old-gen. So we need special
259 // handling for concurrent processing encountering an in-progress allocation.
260 // Returns the address after the last actually scanned or NULL if the area could
261 // not be scanned (That should only happen when invoked concurrently with the
262 // mutator).
263 template <class Closure, bool is_gc_active>
264 inline HeapWord* do_oops_on_memregion_in_humongous(MemRegion mr,
265 Closure* cl,
266 G1CollectedHeap* g1h);
267
268 // Returns the block size of the given (dead, potentially having its class unloaded) object
269 // starting at p extending to at most the prev TAMS using the given mark bitmap.
270 inline size_t block_size_using_bitmap(const HeapWord* p, const G1CMBitMap* const prev_bitmap) const;
271 public:
272 HeapRegion(uint hrm_index, G1BlockOffsetTable* bot, MemRegion mr);
273
274 // Initializing the HeapRegion not only resets the data structure, but also
275 // resets the BOT for that heap region.
276 // The default values for clear_space means that we will do the clearing if
277 // there's clearing to be done ourselves. We also always mangle the space.
278 void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
279
280 static int LogOfHRGrainBytes;
281 static int LogOfHRGrainWords;
282 static int LogCardsPerRegion;
283
284 static size_t GrainBytes;
285 static size_t GrainWords;
286 static size_t CardsPerRegion;
287
288 static size_t align_up_to_region_byte_size(size_t sz) {
289 return (sz + (size_t) GrainBytes - 1) &
290 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
291 }
292
293
294 // Returns whether a field is in the same region as the obj it points to.
295 template <typename T>
296 static bool is_in_same_region(T* p, oop obj) {
297 assert(p != NULL, "p can't be NULL");
298 assert(obj != NULL, "obj can't be NULL");
299 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0;
300 }
301
302 static size_t max_region_size();
303 static size_t min_region_size_in_words();
304
305 // It sets up the heap region size (GrainBytes / GrainWords), as
306 // well as other related fields that are based on the heap region
307 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
308 // CardsPerRegion). All those fields are considered constant
309 // throughout the JVM's execution, therefore they should only be set
310 // up once during initialization time.
311 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
312
313 // All allocated blocks are occupied by objects in a HeapRegion
314 bool block_is_obj(const HeapWord* p) const;
315
316 // Returns whether the given object is dead based on TAMS and bitmap.
317 bool is_obj_dead(const oop obj, const G1CMBitMap* const prev_bitmap) const;
318
319 // Returns the object size for all valid block starts
320 // and the amount of unallocated words if called on top()
321 size_t block_size(const HeapWord* p) const;
322
323 // Scans through the region using the bitmap to determine what
324 // objects to call size_t ApplyToMarkedClosure::apply(oop) for.
325 template<typename ApplyToMarkedClosure>
326 inline void apply_to_marked_objects(G1CMBitMap* bitmap, ApplyToMarkedClosure* closure);
327 // Update heap region to be consistent after compaction.
328 void complete_compaction();
329
330 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size);
331 inline HeapWord* allocate_no_bot_updates(size_t word_size);
332 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size);
333
334 // If this region is a member of a HeapRegionManager, the index in that
335 // sequence, otherwise -1.
336 uint hrm_index() const { return _hrm_index; }
337
338 // The number of bytes marked live in the region in the last marking phase.
339 size_t marked_bytes() { return _prev_marked_bytes; }
340 size_t live_bytes() {
341 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
342 }
343
344 // The number of bytes counted in the next marking.
345 size_t next_marked_bytes() { return _next_marked_bytes; }
346 // The number of bytes live wrt the next marking.
347 size_t next_live_bytes() {
348 return
349 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
350 }
351
352 // A lower bound on the amount of garbage bytes in the region.
353 size_t garbage_bytes() {
354 size_t used_at_mark_start_bytes =
355 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
356 return used_at_mark_start_bytes - marked_bytes();
357 }
358
359 // Return the amount of bytes we'll reclaim if we collect this
360 // region. This includes not only the known garbage bytes in the
361 // region but also any unallocated space in it, i.e., [top, end),
362 // since it will also be reclaimed if we collect the region.
363 size_t reclaimable_bytes() {
364 size_t known_live_bytes = live_bytes();
365 assert(known_live_bytes <= capacity(), "sanity");
366 return capacity() - known_live_bytes;
367 }
368
369 // An upper bound on the number of live bytes in the region.
370 size_t max_live_bytes() { return used() - garbage_bytes(); }
371
372 void add_to_marked_bytes(size_t incr_bytes) {
373 _next_marked_bytes = _next_marked_bytes + incr_bytes;
374 }
375
376 void zero_marked_bytes() {
377 _prev_marked_bytes = _next_marked_bytes = 0;
378 }
379
380 const char* get_type_str() const { return _type.get_str(); }
381 const char* get_short_type_str() const { return _type.get_short_str(); }
382 G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); }
383
384 bool is_free() const { return _type.is_free(); }
385
386 bool is_young() const { return _type.is_young(); }
387 bool is_eden() const { return _type.is_eden(); }
388 bool is_survivor() const { return _type.is_survivor(); }
389
390 bool is_humongous() const { return _type.is_humongous(); }
391 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
392 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
393
394 bool is_old() const { return _type.is_old(); }
395
396 bool is_old_or_humongous() const { return _type.is_old_or_humongous(); }
397
398 bool is_old_or_humongous_or_archive() const { return _type.is_old_or_humongous_or_archive(); }
399
400 // A pinned region contains objects which are not moved by garbage collections.
401 // Humongous regions and archive regions are pinned.
402 bool is_pinned() const { return _type.is_pinned(); }
403
404 // An archive region is a pinned region, also tagged as old, which
405 // should not be marked during mark/sweep. This allows the address
406 // space to be shared by JVM instances.
407 bool is_archive() const { return _type.is_archive(); }
408 bool is_open_archive() const { return _type.is_open_archive(); }
409 bool is_closed_archive() const { return _type.is_closed_archive(); }
410
411 // For a humongous region, region in which it starts.
412 HeapRegion* humongous_start_region() const {
413 return _humongous_start_region;
414 }
415
416 // Makes the current region be a "starts humongous" region, i.e.,
417 // the first region in a series of one or more contiguous regions
418 // that will contain a single "humongous" object.
419 //
420 // obj_top : points to the top of the humongous object.
421 // fill_size : size of the filler object at the end of the region series.
422 void set_starts_humongous(HeapWord* obj_top, size_t fill_size);
423
424 // Makes the current region be a "continues humongous'
425 // region. first_hr is the "start humongous" region of the series
426 // which this region will be part of.
427 void set_continues_humongous(HeapRegion* first_hr);
428
429 // Unsets the humongous-related fields on the region.
430 void clear_humongous();
431
432 // If the region has a remembered set, return a pointer to it.
433 HeapRegionRemSet* rem_set() const {
434 return _rem_set;
435 }
436
437 inline bool in_collection_set() const;
438
439 // Methods used by the HeapRegionSetBase class and subclasses.
440
441 // Getter and setter for the next and prev fields used to link regions into
442 // linked lists.
443 HeapRegion* next() { return _next; }
444 HeapRegion* prev() { return _prev; }
445
446 void set_next(HeapRegion* next) { _next = next; }
447 void set_prev(HeapRegion* prev) { _prev = prev; }
448
449 // Every region added to a set is tagged with a reference to that
450 // set. This is used for doing consistency checking to make sure that
451 // the contents of a set are as they should be and it's only
452 // available in non-product builds.
453 #ifdef ASSERT
454 void set_containing_set(HeapRegionSetBase* containing_set) {
455 assert((containing_set == NULL && _containing_set != NULL) ||
456 (containing_set != NULL && _containing_set == NULL),
457 "containing_set: " PTR_FORMAT " "
458 "_containing_set: " PTR_FORMAT,
459 p2i(containing_set), p2i(_containing_set));
460
461 _containing_set = containing_set;
462 }
463
464 HeapRegionSetBase* containing_set() { return _containing_set; }
465 #else // ASSERT
466 void set_containing_set(HeapRegionSetBase* containing_set) { }
467
468 // containing_set() is only used in asserts so there's no reason
469 // to provide a dummy version of it.
470 #endif // ASSERT
471
472
473 // Reset the HeapRegion to default values.
474 // If skip_remset is true, do not clear the remembered set.
475 // If clear_space is true, clear the HeapRegion's memory.
476 // If locked is true, assume we are the only thread doing this operation.
477 void hr_clear(bool skip_remset, bool clear_space, bool locked = false);
478 // Clear the card table corresponding to this region.
479 void clear_cardtable();
480
481 // Get the start of the unmarked area in this region.
482 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
483 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
484
485 // Note the start or end of marking. This tells the heap region
486 // that the collector is about to start or has finished (concurrently)
487 // marking the heap.
488
489 // Notify the region that concurrent marking is starting. Initialize
490 // all fields related to the next marking info.
491 inline void note_start_of_marking();
492
493 // Notify the region that concurrent marking has finished. Copy the
494 // (now finalized) next marking info fields into the prev marking
495 // info fields.
496 inline void note_end_of_marking();
497
498 // Notify the region that we are about to start processing
499 // self-forwarded objects during evac failure handling.
500 void note_self_forwarding_removal_start(bool during_initial_mark,
501 bool during_conc_mark);
502
503 // Notify the region that we have finished processing self-forwarded
504 // objects during evac failure handling.
505 void note_self_forwarding_removal_end(size_t marked_bytes);
506
507 void reset_during_compaction() {
508 assert(is_humongous(),
509 "should only be called for humongous regions");
510
511 zero_marked_bytes();
512 init_top_at_mark_start();
513 }
514
515 void calc_gc_efficiency(void);
516 double gc_efficiency() const { return _gc_efficiency;}
517
518 uint index_in_opt_cset() const {
519 assert(has_index_in_opt_cset(), "Opt cset index not set.");
520 return _index_in_opt_cset;
521 }
522 bool has_index_in_opt_cset() const { return _index_in_opt_cset != InvalidCSetIndex; }
523 void set_index_in_opt_cset(uint index) { _index_in_opt_cset = index; }
524 void clear_index_in_opt_cset() { _index_in_opt_cset = InvalidCSetIndex; }
525
526 uint young_index_in_cset() const { return _young_index_in_cset; }
527 void clear_young_index_in_cset() { _young_index_in_cset = 0; }
528 void set_young_index_in_cset(uint index) {
529 assert(index != UINT_MAX, "just checking");
530 assert(index != 0, "just checking");
531 assert(is_young(), "pre-condition");
532 _young_index_in_cset = index;
533 }
534
535 int age_in_surv_rate_group() {
536 assert(_surv_rate_group != NULL, "pre-condition");
537 assert(_age_index > -1, "pre-condition");
538 return _surv_rate_group->age_in_group(_age_index);
539 }
540
541 void record_surv_words_in_group(size_t words_survived) {
542 assert(_surv_rate_group != NULL, "pre-condition");
543 assert(_age_index > -1, "pre-condition");
544 int age_in_group = age_in_surv_rate_group();
545 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
546 }
547
548 int age_in_surv_rate_group_cond() {
549 if (_surv_rate_group != NULL)
550 return age_in_surv_rate_group();
551 else
552 return -1;
553 }
554
555 SurvRateGroup* surv_rate_group() {
556 return _surv_rate_group;
557 }
558
559 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
560 assert(surv_rate_group != NULL, "pre-condition");
561 assert(_surv_rate_group == NULL, "pre-condition");
562 assert(is_young(), "pre-condition");
563
564 _surv_rate_group = surv_rate_group;
565 _age_index = surv_rate_group->next_age_index();
566 }
567
568 void uninstall_surv_rate_group() {
569 if (_surv_rate_group != NULL) {
570 assert(_age_index > -1, "pre-condition");
571 assert(is_young(), "pre-condition");
572
573 _surv_rate_group = NULL;
574 _age_index = -1;
575 } else {
576 assert(_age_index == -1, "pre-condition");
577 }
578 }
579
580 void set_free();
581
582 void set_eden();
583 void set_eden_pre_gc();
584 void set_survivor();
585
586 void move_to_old();
587 void set_old();
588
589 void set_open_archive();
590 void set_closed_archive();
591
592 // Determine if an object has been allocated since the last
593 // mark performed by the collector. This returns true iff the object
594 // is within the unmarked area of the region.
595 bool obj_allocated_since_prev_marking(oop obj) const {
596 return (HeapWord *) obj >= prev_top_at_mark_start();
597 }
598 bool obj_allocated_since_next_marking(oop obj) const {
599 return (HeapWord *) obj >= next_top_at_mark_start();
600 }
601
602 // Returns the "evacuation_failed" property of the region.
603 bool evacuation_failed() { return _evacuation_failed; }
604
605 // Sets the "evacuation_failed" property of the region.
606 void set_evacuation_failed(bool b) {
607 _evacuation_failed = b;
608
609 if (b) {
610 _next_marked_bytes = 0;
611 }
612 }
613
614 // Iterate over the objects overlapping the given memory region, applying cl
615 // to all references in the region. This is a helper for
616 // G1RemSet::refine_card*, and is tightly coupled with them.
617 // mr must not be empty. Must be trimmed to the allocated/parseable space in this region.
618 // This region must be old or humongous.
619 // Returns the next unscanned address if the designated objects were successfully
620 // processed, NULL if an unparseable part of the heap was encountered (That should
621 // only happen when invoked concurrently with the mutator).
622 template <bool is_gc_active, class Closure>
623 inline HeapWord* oops_on_memregion_seq_iterate_careful(MemRegion mr, Closure* cl);
624
625 size_t recorded_rs_length() const { return _recorded_rs_length; }
626 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
627
628 void set_recorded_rs_length(size_t rs_length) {
629 _recorded_rs_length = rs_length;
630 }
631
632 void set_predicted_elapsed_time_ms(double ms) {
633 _predicted_elapsed_time_ms = ms;
634 }
635
636 // Routines for managing a list of code roots (attached to the
637 // this region's RSet) that point into this heap region.
638 void add_strong_code_root(nmethod* nm);
639 void add_strong_code_root_locked(nmethod* nm);
640 void remove_strong_code_root(nmethod* nm);
641
642 // Applies blk->do_code_blob() to each of the entries in
643 // the strong code roots list for this region
644 void strong_code_roots_do(CodeBlobClosure* blk) const;
645
646 // Verify that the entries on the strong code root list for this
647 // region are live and include at least one pointer into this region.
648 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
649
650 void print() const;
651 void print_on(outputStream* st) const;
652
653 // vo == UsePrevMarking -> use "prev" marking information,
654 // vo == UseNextMarking -> use "next" marking information
655 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
656 //
657 // NOTE: Only the "prev" marking information is guaranteed to be
658 // consistent most of the time, so most calls to this should use
659 // vo == UsePrevMarking.
660 // Currently, there is only one case where this is called with
661 // vo == UseNextMarking, which is to verify the "next" marking
662 // information at the end of remark.
663 // Currently there is only one place where this is called with
664 // vo == UseFullMarking, which is to verify the marking during a
665 // full GC.
666 void verify(VerifyOption vo, bool *failures) const;
667
668 // Verify using the "prev" marking information
669 void verify() const;
670
671 void verify_rem_set(VerifyOption vo, bool *failures) const;
672 void verify_rem_set() const;
673 };
674
675 // HeapRegionClosure is used for iterating over regions.
676 // Terminates the iteration when the "do_heap_region" method returns "true".
677 class HeapRegionClosure : public StackObj {
678 friend class HeapRegionManager;
679 friend class G1CollectionSet;
680 friend class G1CollectionSetCandidates;
681
682 bool _is_complete;
683 void set_incomplete() { _is_complete = false; }
684
685 public:
686 HeapRegionClosure(): _is_complete(true) {}
687
688 // Typically called on each region until it returns true.
689 virtual bool do_heap_region(HeapRegion* r) = 0;
690
691 // True after iteration if the closure was applied to all heap regions
692 // and returned "false" in all cases.
693 bool is_complete() { return _is_complete; }
694 };
695
696 #endif // SHARE_GC_G1_HEAPREGION_HPP