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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/cardTable.hpp"
35#include "gc/shared/verifyOption.hpp"
36#include "gc/shared/spaceDecorator.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// Each heap region is self contained. top() and end() can never
50// be set beyond the end of the region. For humongous objects,
51// the first region is a StartsHumongous region. If the humongous
52// object is larger than a heap region, the following regions will
53// be of type ContinuesHumongous. In this case the top() of the
54// StartHumongous region and all ContinuesHumongous regions except
55// the last will point to their own end. The last ContinuesHumongous
56// region may have top() equal the end of object if there isn't
57// room for filler objects to pad out to the end of the region.
58
59class G1CollectedHeap;
60class G1CMBitMap;
61class G1IsAliveAndApplyClosure;
62class HeapRegionRemSet;
63class HeapRegionRemSetIterator;
64class HeapRegion;
65class HeapRegionSetBase;
66class nmethod;
67
68#define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]"
69#define HR_FORMAT_PARAMS(_hr_) \
70 (_hr_)->hrm_index(), \
71 (_hr_)->get_short_type_str(), \
72 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
73
74// sentinel value for hrm_index
75#define G1_NO_HRM_INDEX ((uint) -1)
76
77// The complicating factor is that BlockOffsetTable diverged
78// significantly, and we need functionality that is only in the G1 version.
79// So I copied that code, which led to an alternate G1 version of
80// OffsetTableContigSpace. If the two versions of BlockOffsetTable could
81// be reconciled, then G1OffsetTableContigSpace could go away.
82
83// The idea behind time stamps is the following. We want to keep track of
84// the highest address where it's safe to scan objects for each region.
85// This is only relevant for current GC alloc regions so we keep a time stamp
86// per region to determine if the region has been allocated during the current
87// GC or not. If the time stamp is current we report a scan_top value which
88// was saved at the end of the previous GC for retained alloc regions and which is
89// equal to the bottom for all other regions.
90// There is a race between card scanners and allocating gc workers where we must ensure
91// that card scanners do not read the memory allocated by the gc workers.
92// In order to enforce that, we must not return a value of _top which is more recent than the
93// time stamp. This is due to the fact that a region may become a gc alloc region at
94// some point after we've read the timestamp value as being < the current time stamp.
95// The time stamps are re-initialized to zero at cleanup and at Full GCs.
96// The current scheme that uses sequential unsigned ints will fail only if we have 4b
97// evacuation pauses between two cleanups, which is _highly_ unlikely.
98class G1ContiguousSpace: public CompactibleSpace {
99 friend class VMStructs;
100 HeapWord* volatile _top;
101 protected:
102 G1BlockOffsetTablePart _bot_part;
103 Mutex _par_alloc_lock;
104 // When we need to retire an allocation region, while other threads
105 // are also concurrently trying to allocate into it, we typically
106 // allocate a dummy object at the end of the region to ensure that
107 // no more allocations can take place in it. However, sometimes we
108 // want to know where the end of the last "real" object we allocated
109 // into the region was and this is what this keeps track.
110 HeapWord* _pre_dummy_top;
111
112 public:
113 G1ContiguousSpace(G1BlockOffsetTable* bot);
114
115 void set_top(HeapWord* value) { _top = value; }
116 HeapWord* top() const { return _top; }
117
118 protected:
119 // Reset the G1ContiguousSpace.
120 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
121
122 HeapWord* volatile* top_addr() { return &_top; }
123 // Try to allocate at least min_word_size and up to desired_size from this Space.
124 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
125 // space allocated.
126 // This version assumes that all allocation requests to this Space are properly
127 // synchronized.
128 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
129 // Try to allocate at least min_word_size and up to desired_size from this Space.
130 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
131 // space allocated.
132 // This version synchronizes with other calls to par_allocate_impl().
133 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
134
135 public:
136 void reset_after_compaction() { set_top(compaction_top()); }
137
138 size_t used() const { return byte_size(bottom(), top()); }
139 size_t free() const { return byte_size(top(), end()); }
140 bool is_free_block(const HeapWord* p) const { return p >= top(); }
141
142 MemRegion used_region() const { return MemRegion(bottom(), top()); }
143
144 void object_iterate(ObjectClosure* blk);
145 void safe_object_iterate(ObjectClosure* blk);
146
147 void mangle_unused_area() PRODUCT_RETURN;
148 void mangle_unused_area_complete() PRODUCT_RETURN;
149
150 // See the comment above in the declaration of _pre_dummy_top for an
151 // explanation of what it is.
152 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
153 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
154 _pre_dummy_top = pre_dummy_top;
155 }
156 HeapWord* pre_dummy_top() {
157 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
158 }
159 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
160
161 virtual void clear(bool mangle_space);
162
163 HeapWord* block_start(const void* p);
164 HeapWord* block_start_const(const void* p) const;
165
166 // Allocation (return NULL if full). Assumes the caller has established
167 // mutually exclusive access to the space.
168 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
169 // Allocation (return NULL if full). Enforces mutual exclusion internally.
170 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
171
172 virtual HeapWord* allocate(size_t word_size);
173 virtual HeapWord* par_allocate(size_t word_size);
174
175 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
176
177 // MarkSweep support phase3
178 virtual HeapWord* initialize_threshold();
179 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
180
181 virtual void print() const;
182
183 void reset_bot() {
184 _bot_part.reset_bot();
185 }
186
187 void print_bot_on(outputStream* out) {
188 _bot_part.print_on(out);
189 }
190};
191
192class HeapRegion: public G1ContiguousSpace {
193 friend class VMStructs;
194 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
195 template <typename SpaceType>
196 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
197 private:
198
199 // The remembered set for this region.
200 // (Might want to make this "inline" later, to avoid some alloc failure
201 // issues.)
202 HeapRegionRemSet* _rem_set;
203
204 // Auxiliary functions for scan_and_forward support.
205 // See comments for CompactibleSpace for more information.
206 inline HeapWord* scan_limit() const {
207 return top();
208 }
209
210 inline bool scanned_block_is_obj(const HeapWord* addr) const {
211 return true; // Always true, since scan_limit is top
212 }
213
214 inline size_t scanned_block_size(const HeapWord* addr) const {
215 return HeapRegion::block_size(addr); // Avoid virtual call
216 }
217
218 void report_region_type_change(G1HeapRegionTraceType::Type to);
219
220 // Returns whether the given object address refers to a dead object, and either the
221 // size of the object (if live) or the size of the block (if dead) in size.
222 // May
223 // - only called with obj < top()
224 // - not called on humongous objects or archive regions
225 inline bool is_obj_dead_with_size(const oop obj, const G1CMBitMap* const prev_bitmap, size_t* size) const;
226
227 protected:
228 // The index of this region in the heap region sequence.
229 uint _hrm_index;
230
231 HeapRegionType _type;
232
233 // For a humongous region, region in which it starts.
234 HeapRegion* _humongous_start_region;
235
236 // True iff an attempt to evacuate an object in the region failed.
237 bool _evacuation_failed;
238
239 // Fields used by the HeapRegionSetBase class and subclasses.
240 HeapRegion* _next;
241 HeapRegion* _prev;
242#ifdef ASSERT
243 HeapRegionSetBase* _containing_set;
244#endif // ASSERT
245
246 // We use concurrent marking to determine the amount of live data
247 // in each heap region.
248 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
249 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
250
251 // The calculated GC efficiency of the region.
252 double _gc_efficiency;
253
254 static const uint InvalidCSetIndex = UINT_MAX;
255
256 // The index in the optional regions array, if this region
257 // is considered optional during a mixed collections.
258 uint _index_in_opt_cset;
259 int _young_index_in_cset;
260 SurvRateGroup* _surv_rate_group;
261 int _age_index;
262
263 // The start of the unmarked area. The unmarked area extends from this
264 // word until the top and/or end of the region, and is the part
265 // of the region for which no marking was done, i.e. objects may
266 // have been allocated in this part since the last mark phase.
267 // "prev" is the top at the start of the last completed marking.
268 // "next" is the top at the start of the in-progress marking (if any.)
269 HeapWord* _prev_top_at_mark_start;
270 HeapWord* _next_top_at_mark_start;
271 // If a collection pause is in progress, this is the top at the start
272 // of that pause.
273
274 void init_top_at_mark_start() {
275 assert(_prev_marked_bytes == 0 &&
276 _next_marked_bytes == 0,
277 "Must be called after zero_marked_bytes.");
278 HeapWord* bot = bottom();
279 _prev_top_at_mark_start = bot;
280 _next_top_at_mark_start = bot;
281 }
282
283 // Cached attributes used in the collection set policy information
284
285 // The RSet length that was added to the total value
286 // for the collection set.
287 size_t _recorded_rs_length;
288
289 // The predicted elapsed time that was added to total value
290 // for the collection set.
291 double _predicted_elapsed_time_ms;
292
293 // Iterate over the references in a humongous objects and apply the given closure
294 // to them.
295 // Humongous objects are allocated directly in the old-gen. So we need special
296 // handling for concurrent processing encountering an in-progress allocation.
297 template <class Closure, bool is_gc_active>
298 inline bool do_oops_on_card_in_humongous(MemRegion mr,
299 Closure* cl,
300 G1CollectedHeap* g1h);
301
302 // Returns the block size of the given (dead, potentially having its class unloaded) object
303 // starting at p extending to at most the prev TAMS using the given mark bitmap.
304 inline size_t block_size_using_bitmap(const HeapWord* p, const G1CMBitMap* const prev_bitmap) const;
305 public:
306 HeapRegion(uint hrm_index,
307 G1BlockOffsetTable* bot,
308 MemRegion mr);
309
310 // Initializing the HeapRegion not only resets the data structure, but also
311 // resets the BOT for that heap region.
312 // The default values for clear_space means that we will do the clearing if
313 // there's clearing to be done ourselves. We also always mangle the space.
314 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
315
316 static int LogOfHRGrainBytes;
317 static int LogOfHRGrainWords;
318
319 static size_t GrainBytes;
320 static size_t GrainWords;
321 static size_t CardsPerRegion;
322
323 static size_t align_up_to_region_byte_size(size_t sz) {
324 return (sz + (size_t) GrainBytes - 1) &
325 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
326 }
327
328
329 // Returns whether a field is in the same region as the obj it points to.
330 template <typename T>
331 static bool is_in_same_region(T* p, oop obj) {
332 assert(p != NULL, "p can't be NULL");
333 assert(obj != NULL, "obj can't be NULL");
334 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0;
335 }
336
337 static size_t max_region_size();
338 static size_t min_region_size_in_words();
339
340 // It sets up the heap region size (GrainBytes / GrainWords), as
341 // well as other related fields that are based on the heap region
342 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
343 // CardsPerRegion). All those fields are considered constant
344 // throughout the JVM's execution, therefore they should only be set
345 // up once during initialization time.
346 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
347
348 // All allocated blocks are occupied by objects in a HeapRegion
349 bool block_is_obj(const HeapWord* p) const;
350
351 // Returns whether the given object is dead based on TAMS and bitmap.
352 bool is_obj_dead(const oop obj, const G1CMBitMap* const prev_bitmap) const;
353
354 // Returns the object size for all valid block starts
355 // and the amount of unallocated words if called on top()
356 size_t block_size(const HeapWord* p) const;
357
358 // Scans through the region using the bitmap to determine what
359 // objects to call size_t ApplyToMarkedClosure::apply(oop) for.
360 template<typename ApplyToMarkedClosure>
361 inline void apply_to_marked_objects(G1CMBitMap* bitmap, ApplyToMarkedClosure* closure);
362 // Override for scan_and_forward support.
363 void prepare_for_compaction(CompactPoint* cp);
364 // Update heap region to be consistent after compaction.
365 void complete_compaction();
366
367 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size);
368 inline HeapWord* allocate_no_bot_updates(size_t word_size);
369 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size);
370
371 // If this region is a member of a HeapRegionManager, the index in that
372 // sequence, otherwise -1.
373 uint hrm_index() const { return _hrm_index; }
374
375 // The number of bytes marked live in the region in the last marking phase.
376 size_t marked_bytes() { return _prev_marked_bytes; }
377 size_t live_bytes() {
378 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
379 }
380
381 // The number of bytes counted in the next marking.
382 size_t next_marked_bytes() { return _next_marked_bytes; }
383 // The number of bytes live wrt the next marking.
384 size_t next_live_bytes() {
385 return
386 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
387 }
388
389 // A lower bound on the amount of garbage bytes in the region.
390 size_t garbage_bytes() {
391 size_t used_at_mark_start_bytes =
392 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
393 return used_at_mark_start_bytes - marked_bytes();
394 }
395
396 // Return the amount of bytes we'll reclaim if we collect this
397 // region. This includes not only the known garbage bytes in the
398 // region but also any unallocated space in it, i.e., [top, end),
399 // since it will also be reclaimed if we collect the region.
400 size_t reclaimable_bytes() {
401 size_t known_live_bytes = live_bytes();
402 assert(known_live_bytes <= capacity(), "sanity");
403 return capacity() - known_live_bytes;
404 }
405
406 // An upper bound on the number of live bytes in the region.
407 size_t max_live_bytes() { return used() - garbage_bytes(); }
408
409 void add_to_marked_bytes(size_t incr_bytes) {
410 _next_marked_bytes = _next_marked_bytes + incr_bytes;
411 }
412
413 void zero_marked_bytes() {
414 _prev_marked_bytes = _next_marked_bytes = 0;
415 }
416
417 const char* get_type_str() const { return _type.get_str(); }
418 const char* get_short_type_str() const { return _type.get_short_str(); }
419 G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); }
420
421 bool is_free() const { return _type.is_free(); }
422
423 bool is_young() const { return _type.is_young(); }
424 bool is_eden() const { return _type.is_eden(); }
425 bool is_survivor() const { return _type.is_survivor(); }
426
427 bool is_humongous() const { return _type.is_humongous(); }
428 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
429 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
430
431 bool is_old() const { return _type.is_old(); }
432
433 bool is_old_or_humongous() const { return _type.is_old_or_humongous(); }
434
435 bool is_old_or_humongous_or_archive() const { return _type.is_old_or_humongous_or_archive(); }
436
437 // A pinned region contains objects which are not moved by garbage collections.
438 // Humongous regions and archive regions are pinned.
439 bool is_pinned() const { return _type.is_pinned(); }
440
441 // An archive region is a pinned region, also tagged as old, which
442 // should not be marked during mark/sweep. This allows the address
443 // space to be shared by JVM instances.
444 bool is_archive() const { return _type.is_archive(); }
445 bool is_open_archive() const { return _type.is_open_archive(); }
446 bool is_closed_archive() const { return _type.is_closed_archive(); }
447
448 // For a humongous region, region in which it starts.
449 HeapRegion* humongous_start_region() const {
450 return _humongous_start_region;
451 }
452
453 // Makes the current region be a "starts humongous" region, i.e.,
454 // the first region in a series of one or more contiguous regions
455 // that will contain a single "humongous" object.
456 //
457 // obj_top : points to the top of the humongous object.
458 // fill_size : size of the filler object at the end of the region series.
459 void set_starts_humongous(HeapWord* obj_top, size_t fill_size);
460
461 // Makes the current region be a "continues humongous'
462 // region. first_hr is the "start humongous" region of the series
463 // which this region will be part of.
464 void set_continues_humongous(HeapRegion* first_hr);
465
466 // Unsets the humongous-related fields on the region.
467 void clear_humongous();
468
469 // If the region has a remembered set, return a pointer to it.
470 HeapRegionRemSet* rem_set() const {
471 return _rem_set;
472 }
473
474 inline bool in_collection_set() const;
475
476 // Methods used by the HeapRegionSetBase class and subclasses.
477
478 // Getter and setter for the next and prev fields used to link regions into
479 // linked lists.
480 HeapRegion* next() { return _next; }
481 HeapRegion* prev() { return _prev; }
482
483 void set_next(HeapRegion* next) { _next = next; }
484 void set_prev(HeapRegion* prev) { _prev = prev; }
485
486 // Every region added to a set is tagged with a reference to that
487 // set. This is used for doing consistency checking to make sure that
488 // the contents of a set are as they should be and it's only
489 // available in non-product builds.
490#ifdef ASSERT
491 void set_containing_set(HeapRegionSetBase* containing_set) {
492 assert((containing_set == NULL && _containing_set != NULL) ||
493 (containing_set != NULL && _containing_set == NULL),
494 "containing_set: " PTR_FORMAT " "
495 "_containing_set: " PTR_FORMAT,
496 p2i(containing_set), p2i(_containing_set));
497
498 _containing_set = containing_set;
499 }
500
501 HeapRegionSetBase* containing_set() { return _containing_set; }
502#else // ASSERT
503 void set_containing_set(HeapRegionSetBase* containing_set) { }
504
505 // containing_set() is only used in asserts so there's no reason
506 // to provide a dummy version of it.
507#endif // ASSERT
508
509
510 // Reset the HeapRegion to default values.
511 // If skip_remset is true, do not clear the remembered set.
512 // If clear_space is true, clear the HeapRegion's memory.
513 // If locked is true, assume we are the only thread doing this operation.
514 void hr_clear(bool skip_remset, bool clear_space, bool locked = false);
515 // Clear the card table corresponding to this region.
516 void clear_cardtable();
517
518 // Get the start of the unmarked area in this region.
519 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
520 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
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
526 // Notify the region that concurrent marking is starting. Initialize
527 // all fields related to the next marking info.
528 inline void note_start_of_marking();
529
530 // Notify the region that concurrent marking has finished. Copy the
531 // (now finalized) next marking info fields into the prev marking
532 // info fields.
533 inline void note_end_of_marking();
534
535 // Notify the region that we are about to start processing
536 // self-forwarded objects during evac failure handling.
537 void note_self_forwarding_removal_start(bool during_initial_mark,
538 bool during_conc_mark);
539
540 // Notify the region that we have finished processing self-forwarded
541 // objects during evac failure handling.
542 void note_self_forwarding_removal_end(size_t marked_bytes);
543
544 void reset_during_compaction() {
545 assert(is_humongous(),
546 "should only be called for humongous regions");
547
548 zero_marked_bytes();
549 init_top_at_mark_start();
550 }
551
552 void calc_gc_efficiency(void);
553 double gc_efficiency() const { return _gc_efficiency;}
554
555 uint index_in_opt_cset() const {
556 assert(has_index_in_opt_cset(), "Opt cset index not set.");
557 return _index_in_opt_cset;
558 }
559 bool has_index_in_opt_cset() const { return _index_in_opt_cset != InvalidCSetIndex; }
560 void set_index_in_opt_cset(uint index) { _index_in_opt_cset = index; }
561 void clear_index_in_opt_cset() { _index_in_opt_cset = InvalidCSetIndex; }
562
563 int young_index_in_cset() const { return _young_index_in_cset; }
564 void set_young_index_in_cset(int index) {
565 assert( (index == -1) || is_young(), "pre-condition" );
566 _young_index_in_cset = index;
567 }
568
569 int age_in_surv_rate_group() {
570 assert( _surv_rate_group != NULL, "pre-condition" );
571 assert( _age_index > -1, "pre-condition" );
572 return _surv_rate_group->age_in_group(_age_index);
573 }
574
575 void record_surv_words_in_group(size_t words_survived) {
576 assert( _surv_rate_group != NULL, "pre-condition" );
577 assert( _age_index > -1, "pre-condition" );
578 int age_in_group = age_in_surv_rate_group();
579 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
580 }
581
582 int age_in_surv_rate_group_cond() {
583 if (_surv_rate_group != NULL)
584 return age_in_surv_rate_group();
585 else
586 return -1;
587 }
588
589 SurvRateGroup* surv_rate_group() {
590 return _surv_rate_group;
591 }
592
593 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
594 assert( surv_rate_group != NULL, "pre-condition" );
595 assert( _surv_rate_group == NULL, "pre-condition" );
596 assert( is_young(), "pre-condition" );
597
598 _surv_rate_group = surv_rate_group;
599 _age_index = surv_rate_group->next_age_index();
600 }
601
602 void uninstall_surv_rate_group() {
603 if (_surv_rate_group != NULL) {
604 assert( _age_index > -1, "pre-condition" );
605 assert( is_young(), "pre-condition" );
606
607 _surv_rate_group = NULL;
608 _age_index = -1;
609 } else {
610 assert( _age_index == -1, "pre-condition" );
611 }
612 }
613
614 void set_free();
615
616 void set_eden();
617 void set_eden_pre_gc();
618 void set_survivor();
619
620 void move_to_old();
621 void set_old();
622
623 void set_open_archive();
624 void set_closed_archive();
625
626 // Determine if an object has been allocated since the last
627 // mark performed by the collector. This returns true iff the object
628 // is within the unmarked area of the region.
629 bool obj_allocated_since_prev_marking(oop obj) const {
630 return (HeapWord *) obj >= prev_top_at_mark_start();
631 }
632 bool obj_allocated_since_next_marking(oop obj) const {
633 return (HeapWord *) obj >= next_top_at_mark_start();
634 }
635
636 // Returns the "evacuation_failed" property of the region.
637 bool evacuation_failed() { return _evacuation_failed; }
638
639 // Sets the "evacuation_failed" property of the region.
640 void set_evacuation_failed(bool b) {
641 _evacuation_failed = b;
642
643 if (b) {
644 _next_marked_bytes = 0;
645 }
646 }
647
648 // Iterate over the objects overlapping part of a card, applying cl
649 // to all references in the region. This is a helper for
650 // G1RemSet::refine_card*, and is tightly coupled with them.
651 // mr is the memory region covered by the card, trimmed to the
652 // allocated space for this region. Must not be empty.
653 // This region must be old or humongous.
654 // Returns true if the designated objects were successfully
655 // processed, false if an unparsable part of the heap was
656 // encountered; that only happens when invoked concurrently with the
657 // mutator.
658 template <bool is_gc_active, class Closure>
659 inline bool oops_on_card_seq_iterate_careful(MemRegion mr, Closure* cl);
660
661 size_t recorded_rs_length() const { return _recorded_rs_length; }
662 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
663
664 void set_recorded_rs_length(size_t rs_length) {
665 _recorded_rs_length = rs_length;
666 }
667
668 void set_predicted_elapsed_time_ms(double ms) {
669 _predicted_elapsed_time_ms = ms;
670 }
671
672 // Routines for managing a list of code roots (attached to the
673 // this region's RSet) that point into this heap region.
674 void add_strong_code_root(nmethod* nm);
675 void add_strong_code_root_locked(nmethod* nm);
676 void remove_strong_code_root(nmethod* nm);
677
678 // Applies blk->do_code_blob() to each of the entries in
679 // the strong code roots list for this region
680 void strong_code_roots_do(CodeBlobClosure* blk) const;
681
682 // Verify that the entries on the strong code root list for this
683 // region are live and include at least one pointer into this region.
684 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
685
686 void print() const;
687 void print_on(outputStream* st) const;
688
689 // vo == UsePrevMarking -> use "prev" marking information,
690 // vo == UseNextMarking -> use "next" marking information
691 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
692 //
693 // NOTE: Only the "prev" marking information is guaranteed to be
694 // consistent most of the time, so most calls to this should use
695 // vo == UsePrevMarking.
696 // Currently, there is only one case where this is called with
697 // vo == UseNextMarking, which is to verify the "next" marking
698 // information at the end of remark.
699 // Currently there is only one place where this is called with
700 // vo == UseFullMarking, which is to verify the marking during a
701 // full GC.
702 void verify(VerifyOption vo, bool *failures) const;
703
704 // Override; it uses the "prev" marking information
705 virtual void verify() const;
706
707 void verify_rem_set(VerifyOption vo, bool *failures) const;
708 void verify_rem_set() const;
709};
710
711// HeapRegionClosure is used for iterating over regions.
712// Terminates the iteration when the "do_heap_region" method returns "true".
713class HeapRegionClosure : public StackObj {
714 friend class HeapRegionManager;
715 friend class G1CollectionSet;
716 friend class G1CollectionSetCandidates;
717
718 bool _is_complete;
719 void set_incomplete() { _is_complete = false; }
720
721 public:
722 HeapRegionClosure(): _is_complete(true) {}
723
724 // Typically called on each region until it returns true.
725 virtual bool do_heap_region(HeapRegion* r) = 0;
726
727 // True after iteration if the closure was applied to all heap regions
728 // and returned "false" in all cases.
729 bool is_complete() { return _is_complete; }
730};
731
732#endif // SHARE_GC_G1_HEAPREGION_HPP
733