1 /*
2 * Copyright (c) 2001, 2017, 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
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
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/g1HeapRegionTraceType.hpp"
31 #include "gc/g1/heapRegionTracer.hpp"
32 #include "gc/g1/heapRegionType.hpp"
33 #include "gc/g1/survRateGroup.hpp"
34 #include "gc/shared/ageTable.hpp"
35 #include "gc/shared/spaceDecorator.hpp"
36 #include "utilities/macros.hpp"
37
38 // A HeapRegion is the smallest piece of a G1CollectedHeap that
39 // can be collected independently.
40
41 // NOTE: Although a HeapRegion is a Space, its
42 // Space::initDirtyCardClosure method must not be called.
43 // The problem is that the existence of this method breaks
44 // the independence of barrier sets from remembered sets.
45 // The solution is to remove this method from the definition
46 // of a Space.
47
48 // Each heap region is self contained. top() and end() can never
49 // be set beyond the end of the region. For humongous objects,
50 // the first region is a StartsHumongous region. If the humongous
51 // object is larger than a heap region, the following regions will
52 // be of type ContinuesHumongous. In this case the top() of the
53 // StartHumongous region and all ContinuesHumongous regions except
54 // the last will point to their own end. The last ContinuesHumongous
55 // region may have top() equal the end of object if there isn't
56 // room for filler objects to pad out to the end of the region.
57
58 class G1CollectedHeap;
59 class G1CMBitMapRO;
60 class HeapRegionRemSet;
61 class HeapRegionRemSetIterator;
62 class HeapRegion;
63 class HeapRegionSetBase;
64 class nmethod;
65
66 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]"
67 #define HR_FORMAT_PARAMS(_hr_) \
68 (_hr_)->hrm_index(), \
69 (_hr_)->get_short_type_str(), \
70 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
71
72 // sentinel value for hrm_index
73 #define G1_NO_HRM_INDEX ((uint) -1)
74
75 // The complicating factor is that BlockOffsetTable diverged
76 // significantly, and we need functionality that is only in the G1 version.
77 // So I copied that code, which led to an alternate G1 version of
78 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could
79 // be reconciled, then G1OffsetTableContigSpace could go away.
80
81 // The idea behind time stamps is the following. We want to keep track of
82 // the highest address where it's safe to scan objects for each region.
83 // This is only relevant for current GC alloc regions so we keep a time stamp
84 // per region to determine if the region has been allocated during the current
85 // GC or not. If the time stamp is current we report a scan_top value which
86 // was saved at the end of the previous GC for retained alloc regions and which is
87 // equal to the bottom for all other regions.
88 // There is a race between card scanners and allocating gc workers where we must ensure
89 // that card scanners do not read the memory allocated by the gc workers.
90 // In order to enforce that, we must not return a value of _top which is more recent than the
91 // time stamp. This is due to the fact that a region may become a gc alloc region at
92 // some point after we've read the timestamp value as being < the current time stamp.
93 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
94 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
95 // evacuation pauses between two cleanups, which is _highly_ unlikely.
96 class G1ContiguousSpace: public CompactibleSpace {
97 friend class VMStructs;
98 HeapWord* volatile _top;
99 protected:
100 G1BlockOffsetTablePart _bot_part;
101 Mutex _par_alloc_lock;
102 volatile uint _gc_time_stamp;
103 // When we need to retire an allocation region, while other threads
104 // are also concurrently trying to allocate into it, we typically
105 // allocate a dummy object at the end of the region to ensure that
106 // no more allocations can take place in it. However, sometimes we
107 // want to know where the end of the last "real" object we allocated
108 // into the region was and this is what this keeps track.
109 HeapWord* _pre_dummy_top;
110
111 public:
112 G1ContiguousSpace(G1BlockOffsetTable* bot);
113
114 void set_top(HeapWord* value) { _top = value; }
115 HeapWord* top() const { return _top; }
116
117 protected:
118 // Reset the G1ContiguousSpace.
119 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
120
121 HeapWord* volatile* top_addr() { return &_top; }
122 // Try to allocate at least min_word_size and up to desired_size from this Space.
123 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
124 // space allocated.
125 // This version assumes that all allocation requests to this Space are properly
126 // synchronized.
127 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
128 // Try to allocate at least min_word_size and up to desired_size from this Space.
129 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
130 // space allocated.
131 // This version synchronizes with other calls to par_allocate_impl().
132 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
133
134 public:
135 void reset_after_compaction() { set_top(compaction_top()); }
136
137 size_t used() const { return byte_size(bottom(), top()); }
138 size_t free() const { return byte_size(top(), end()); }
139 bool is_free_block(const HeapWord* p) const { return p >= top(); }
140
141 MemRegion used_region() const { return MemRegion(bottom(), top()); }
142
143 void object_iterate(ObjectClosure* blk);
144 void safe_object_iterate(ObjectClosure* blk);
145
146 void mangle_unused_area() PRODUCT_RETURN;
147 void mangle_unused_area_complete() PRODUCT_RETURN;
148
149 void record_timestamp();
150 void reset_gc_time_stamp() { _gc_time_stamp = 0; }
151 uint get_gc_time_stamp() { return _gc_time_stamp; }
152
153 // See the comment above in the declaration of _pre_dummy_top for an
154 // explanation of what it is.
155 void set_pre_dummy_top(HeapWord* pre_dummy_top) {
156 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
157 _pre_dummy_top = pre_dummy_top;
158 }
159 HeapWord* pre_dummy_top() {
160 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
161 }
162 void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
163
164 virtual void clear(bool mangle_space);
165
166 HeapWord* block_start(const void* p);
167 HeapWord* block_start_const(const void* p) const;
168
169 // Allocation (return NULL if full). Assumes the caller has established
170 // mutually exclusive access to the space.
171 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
172 // Allocation (return NULL if full). Enforces mutual exclusion internally.
173 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
174
175 virtual HeapWord* allocate(size_t word_size);
176 virtual HeapWord* par_allocate(size_t word_size);
177
178 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
179
180 // MarkSweep support phase3
181 virtual HeapWord* initialize_threshold();
182 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
183
184 virtual void print() const;
185
186 void reset_bot() {
187 _bot_part.reset_bot();
188 }
189
190 void print_bot_on(outputStream* out) {
191 _bot_part.print_on(out);
192 }
193 };
194
195 class HeapRegion: public G1ContiguousSpace {
196 friend class VMStructs;
197 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
198 template <typename SpaceType>
199 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
200 private:
201
202 // The remembered set for this region.
203 // (Might want to make this "inline" later, to avoid some alloc failure
204 // issues.)
205 HeapRegionRemSet* _rem_set;
206
207 // Auxiliary functions for scan_and_forward support.
208 // See comments for CompactibleSpace for more information.
209 inline HeapWord* scan_limit() const {
210 return top();
211 }
212
213 inline bool scanned_block_is_obj(const HeapWord* addr) const {
214 return true; // Always true, since scan_limit is top
215 }
216
217 inline size_t scanned_block_size(const HeapWord* addr) const {
218 return HeapRegion::block_size(addr); // Avoid virtual call
219 }
220
221 void report_region_type_change(G1HeapRegionTraceType::Type to);
222
223 // Returns whether the given object address refers to a dead object, and either the
224 // size of the object (if live) or the size of the block (if dead) in size.
225 // Performs some optimizations if is_gc_active is set.
226 template <bool is_gc_active>
227 inline bool is_obj_dead_with_size(const oop obj, G1CMBitMapRO* bitmap, size_t* size) const;
228
229 protected:
230 // The index of this region in the heap region sequence.
231 uint _hrm_index;
232
233 AllocationContext_t _allocation_context;
234
235 HeapRegionType _type;
236
237 // For a humongous region, region in which it starts.
238 HeapRegion* _humongous_start_region;
239
240 // True iff an attempt to evacuate an object in the region failed.
241 bool _evacuation_failed;
242
243 // Fields used by the HeapRegionSetBase class and subclasses.
244 HeapRegion* _next;
245 HeapRegion* _prev;
246 #ifdef ASSERT
247 HeapRegionSetBase* _containing_set;
248 #endif // ASSERT
249
250 // We use concurrent marking to determine the amount of live data
251 // in each heap region.
252 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
253 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking.
254
255 // The calculated GC efficiency of the region.
256 double _gc_efficiency;
257
258 int _young_index_in_cset;
259 SurvRateGroup* _surv_rate_group;
260 int _age_index;
261
262 // The start of the unmarked area. The unmarked area extends from this
263 // word until the top and/or end of the region, and is the part
264 // of the region for which no marking was done, i.e. objects may
265 // have been allocated in this part since the last mark phase.
266 // "prev" is the top at the start of the last completed marking.
267 // "next" is the top at the start of the in-progress marking (if any.)
268 HeapWord* _prev_top_at_mark_start;
269 HeapWord* _next_top_at_mark_start;
270 // If a collection pause is in progress, this is the top at the start
271 // of that pause.
272
273 void init_top_at_mark_start() {
274 assert(_prev_marked_bytes == 0 &&
275 _next_marked_bytes == 0,
276 "Must be called after zero_marked_bytes.");
277 HeapWord* bot = bottom();
278 _prev_top_at_mark_start = bot;
279 _next_top_at_mark_start = bot;
280 }
281
282 // Cached attributes used in the collection set policy information
283
284 // The RSet length that was added to the total value
285 // for the collection set.
286 size_t _recorded_rs_length;
287
288 // The predicted elapsed time that was added to total value
289 // for the collection set.
290 double _predicted_elapsed_time_ms;
291
292 // Iterate over the references in a humongous objects and apply the given closure
293 // to them.
294 // Humongous objects are allocated directly in the old-gen. So we need special
295 // handling for concurrent processing encountering an in-progress allocation.
296 template <class Closure, bool is_gc_active>
297 inline bool do_oops_on_card_in_humongous(MemRegion mr,
298 Closure* cl,
299 G1CollectedHeap* g1h);
300
301 // Returns the block size of the given (dead, potentially having its class unloaded) object
302 // starting at p extending to at most the prev TAMS using the given mark bitmap.
303 inline size_t block_size_using_bitmap(const HeapWord* p, const G1CMBitMapRO* bitmap) const;
304 public:
305 HeapRegion(uint hrm_index,
306 G1BlockOffsetTable* bot,
307 MemRegion mr);
308
309 // Initializing the HeapRegion not only resets the data structure, but also
310 // resets the BOT for that heap region.
311 // The default values for clear_space means that we will do the clearing if
312 // there's clearing to be done ourselves. We also always mangle the space.
313 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
314
315 static int LogOfHRGrainBytes;
316 static int LogOfHRGrainWords;
317
318 static size_t GrainBytes;
319 static size_t GrainWords;
320 static size_t CardsPerRegion;
321
322 static size_t align_up_to_region_byte_size(size_t sz) {
323 return (sz + (size_t) GrainBytes - 1) &
324 ~((1 << (size_t) LogOfHRGrainBytes) - 1);
325 }
326
327
328 // Returns whether a field is in the same region as the obj it points to.
329 template <typename T>
330 static bool is_in_same_region(T* p, oop obj) {
331 assert(p != NULL, "p can't be NULL");
332 assert(obj != NULL, "obj can't be NULL");
333 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0;
334 }
335
336 static size_t max_region_size();
337 static size_t min_region_size_in_words();
338
339 // It sets up the heap region size (GrainBytes / GrainWords), as
340 // well as other related fields that are based on the heap region
341 // size (LogOfHRGrainBytes / LogOfHRGrainWords /
342 // CardsPerRegion). All those fields are considered constant
343 // throughout the JVM's execution, therefore they should only be set
344 // up once during initialization time.
345 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
346
347 // All allocated blocks are occupied by objects in a HeapRegion
348 bool block_is_obj(const HeapWord* p) const;
349
350 // Returns the object size for valid block starts for potentially unloaded dead
351 // objects. Must only be called during scanning cards during GC. Expects the
352 // following preconditions:
353 // - only called on p < top()
354 // - not called on humongous objects or archive regions
355 size_t block_size_during_gc(const HeapWord* p, const G1CMBitMapRO* bitmap) const;
356
357 // Returns the object size for all valid block starts
358 // and the amount of unallocated words if called on top()
359 size_t block_size(const HeapWord* p) const;
360
361 // Override for scan_and_forward support.
362 void prepare_for_compaction(CompactPoint* cp);
363
364 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size);
365 inline HeapWord* allocate_no_bot_updates(size_t word_size);
366 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size);
367
368 // If this region is a member of a HeapRegionManager, the index in that
369 // sequence, otherwise -1.
370 uint hrm_index() const { return _hrm_index; }
371
372 // The number of bytes marked live in the region in the last marking phase.
373 size_t marked_bytes() { return _prev_marked_bytes; }
374 size_t live_bytes() {
375 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
376 }
377
378 // The number of bytes counted in the next marking.
379 size_t next_marked_bytes() { return _next_marked_bytes; }
380 // The number of bytes live wrt the next marking.
381 size_t next_live_bytes() {
382 return
383 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
384 }
385
386 // A lower bound on the amount of garbage bytes in the region.
387 size_t garbage_bytes() {
388 size_t used_at_mark_start_bytes =
389 (prev_top_at_mark_start() - bottom()) * HeapWordSize;
390 return used_at_mark_start_bytes - marked_bytes();
391 }
392
393 // Return the amount of bytes we'll reclaim if we collect this
394 // region. This includes not only the known garbage bytes in the
395 // region but also any unallocated space in it, i.e., [top, end),
396 // since it will also be reclaimed if we collect the region.
397 size_t reclaimable_bytes() {
398 size_t known_live_bytes = live_bytes();
399 assert(known_live_bytes <= capacity(), "sanity");
400 return capacity() - known_live_bytes;
401 }
402
403 // An upper bound on the number of live bytes in the region.
404 size_t max_live_bytes() { return used() - garbage_bytes(); }
405
406 void add_to_marked_bytes(size_t incr_bytes) {
407 _next_marked_bytes = _next_marked_bytes + incr_bytes;
408 }
409
410 void zero_marked_bytes() {
411 _prev_marked_bytes = _next_marked_bytes = 0;
412 }
413
414 const char* get_type_str() const { return _type.get_str(); }
415 const char* get_short_type_str() const { return _type.get_short_str(); }
416 G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); }
417
418 bool is_free() const { return _type.is_free(); }
419
420 bool is_young() const { return _type.is_young(); }
421 bool is_eden() const { return _type.is_eden(); }
422 bool is_survivor() const { return _type.is_survivor(); }
423
424 bool is_humongous() const { return _type.is_humongous(); }
425 bool is_starts_humongous() const { return _type.is_starts_humongous(); }
426 bool is_continues_humongous() const { return _type.is_continues_humongous(); }
427
428 bool is_old() const { return _type.is_old(); }
429
430 bool is_old_or_humongous() const { return _type.is_old_or_humongous(); }
431
432 // A pinned region contains objects which are not moved by garbage collections.
433 // Humongous regions and archive regions are pinned.
434 bool is_pinned() const { return _type.is_pinned(); }
435
436 // An archive region is a pinned region, also tagged as old, which
437 // should not be marked during mark/sweep. This allows the address
438 // space to be shared by JVM instances.
439 bool is_archive() const { return _type.is_archive(); }
440
441 // For a humongous region, region in which it starts.
442 HeapRegion* humongous_start_region() const {
443 return _humongous_start_region;
444 }
445
446 // Makes the current region be a "starts humongous" region, i.e.,
447 // the first region in a series of one or more contiguous regions
448 // that will contain a single "humongous" object.
449 //
450 // obj_top : points to the top of the humongous object.
451 // fill_size : size of the filler object at the end of the region series.
452 void set_starts_humongous(HeapWord* obj_top, size_t fill_size);
453
454 // Makes the current region be a "continues humongous'
455 // region. first_hr is the "start humongous" region of the series
456 // which this region will be part of.
457 void set_continues_humongous(HeapRegion* first_hr);
458
459 // Unsets the humongous-related fields on the region.
460 void clear_humongous();
461
462 // If the region has a remembered set, return a pointer to it.
463 HeapRegionRemSet* rem_set() const {
464 return _rem_set;
465 }
466
467 inline bool in_collection_set() const;
468
469 void set_allocation_context(AllocationContext_t context) {
470 _allocation_context = context;
471 }
472
473 AllocationContext_t allocation_context() const {
474 return _allocation_context;
475 }
476
477 // Methods used by the HeapRegionSetBase class and subclasses.
478
479 // Getter and setter for the next and prev fields used to link regions into
480 // linked lists.
481 HeapRegion* next() { return _next; }
482 HeapRegion* prev() { return _prev; }
483
484 void set_next(HeapRegion* next) { _next = next; }
485 void set_prev(HeapRegion* prev) { _prev = prev; }
486
487 // Every region added to a set is tagged with a reference to that
488 // set. This is used for doing consistency checking to make sure that
489 // the contents of a set are as they should be and it's only
490 // available in non-product builds.
491 #ifdef ASSERT
492 void set_containing_set(HeapRegionSetBase* containing_set) {
493 assert((containing_set == NULL && _containing_set != NULL) ||
494 (containing_set != NULL && _containing_set == NULL),
495 "containing_set: " PTR_FORMAT " "
496 "_containing_set: " PTR_FORMAT,
497 p2i(containing_set), p2i(_containing_set));
498
499 _containing_set = containing_set;
500 }
501
502 HeapRegionSetBase* containing_set() { return _containing_set; }
503 #else // ASSERT
504 void set_containing_set(HeapRegionSetBase* containing_set) { }
505
506 // containing_set() is only used in asserts so there's no reason
507 // to provide a dummy version of it.
508 #endif // ASSERT
509
510
511 // Reset the HeapRegion to default values.
512 // If skip_remset is true, do not clear the remembered set.
513 void hr_clear(bool skip_remset, bool clear_space, bool locked = false);
514 // Clear the parts skipped by skip_remset in hr_clear() in the HeapRegion during
515 // a concurrent phase.
516 void par_clear();
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 it will be used as to-space during a GC
536 // and we are about to start copying objects into it.
537 inline void note_start_of_copying(bool during_initial_mark);
538
539 // Notify the region that it ceases being to-space during a GC and
540 // we will not copy objects into it any more.
541 inline void note_end_of_copying(bool during_initial_mark);
542
543 // Notify the region that we are about to start processing
544 // self-forwarded objects during evac failure handling.
545 void note_self_forwarding_removal_start(bool during_initial_mark,
546 bool during_conc_mark);
547
548 // Notify the region that we have finished processing self-forwarded
549 // objects during evac failure handling.
550 void note_self_forwarding_removal_end(size_t marked_bytes);
551
552 // Returns "false" iff no object in the region was allocated when the
553 // last mark phase ended.
554 bool is_marked() { return _prev_top_at_mark_start != bottom(); }
555
556 void reset_during_compaction() {
557 assert(is_humongous(),
558 "should only be called for humongous regions");
559
560 zero_marked_bytes();
561 init_top_at_mark_start();
562 }
563
564 void calc_gc_efficiency(void);
565 double gc_efficiency() { return _gc_efficiency;}
566
567 int young_index_in_cset() const { return _young_index_in_cset; }
568 void set_young_index_in_cset(int index) {
569 assert( (index == -1) || is_young(), "pre-condition" );
570 _young_index_in_cset = index;
571 }
572
573 int age_in_surv_rate_group() {
574 assert( _surv_rate_group != NULL, "pre-condition" );
575 assert( _age_index > -1, "pre-condition" );
576 return _surv_rate_group->age_in_group(_age_index);
577 }
578
579 void record_surv_words_in_group(size_t words_survived) {
580 assert( _surv_rate_group != NULL, "pre-condition" );
581 assert( _age_index > -1, "pre-condition" );
582 int age_in_group = age_in_surv_rate_group();
583 _surv_rate_group->record_surviving_words(age_in_group, words_survived);
584 }
585
586 int age_in_surv_rate_group_cond() {
587 if (_surv_rate_group != NULL)
588 return age_in_surv_rate_group();
589 else
590 return -1;
591 }
592
593 SurvRateGroup* surv_rate_group() {
594 return _surv_rate_group;
595 }
596
597 void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
598 assert( surv_rate_group != NULL, "pre-condition" );
599 assert( _surv_rate_group == NULL, "pre-condition" );
600 assert( is_young(), "pre-condition" );
601
602 _surv_rate_group = surv_rate_group;
603 _age_index = surv_rate_group->next_age_index();
604 }
605
606 void uninstall_surv_rate_group() {
607 if (_surv_rate_group != NULL) {
608 assert( _age_index > -1, "pre-condition" );
609 assert( is_young(), "pre-condition" );
610
611 _surv_rate_group = NULL;
612 _age_index = -1;
613 } else {
614 assert( _age_index == -1, "pre-condition" );
615 }
616 }
617
618 void set_free();
619
620 void set_eden();
621 void set_eden_pre_gc();
622 void set_survivor();
623
624 void set_old();
625
626 void set_archive();
627
628 // Determine if an object has been allocated since the last
629 // mark performed by the collector. This returns true iff the object
630 // is within the unmarked area of the region.
631 bool obj_allocated_since_prev_marking(oop obj) const {
632 return (HeapWord *) obj >= prev_top_at_mark_start();
633 }
634 bool obj_allocated_since_next_marking(oop obj) const {
635 return (HeapWord *) obj >= next_top_at_mark_start();
636 }
637
638 // Returns the "evacuation_failed" property of the region.
639 bool evacuation_failed() { return _evacuation_failed; }
640
641 // Sets the "evacuation_failed" property of the region.
642 void set_evacuation_failed(bool b) {
643 _evacuation_failed = b;
644
645 if (b) {
646 _next_marked_bytes = 0;
647 }
648 }
649
650 // Iterate over the objects overlapping part of a card, applying cl
651 // to all references in the region. This is a helper for
652 // G1RemSet::refine_card, and is tightly coupled with it.
653 // mr: the memory region covered by the card, trimmed to the
654 // allocated space for this region. Must not be empty.
655 // This region must be old or humongous.
656 // Returns true if the designated objects were successfully
657 // processed, false if an unparsable part of the heap was
658 // encountered; that only happens when invoked concurrently with the
659 // mutator.
660 template <bool is_gc_active, class Closure>
661 inline bool oops_on_card_seq_iterate_careful(MemRegion mr, Closure* cl);
662
663 size_t recorded_rs_length() const { return _recorded_rs_length; }
664 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
665
666 void set_recorded_rs_length(size_t rs_length) {
667 _recorded_rs_length = rs_length;
668 }
669
670 void set_predicted_elapsed_time_ms(double ms) {
671 _predicted_elapsed_time_ms = ms;
672 }
673
674 virtual CompactibleSpace* next_compaction_space() const;
675
676 virtual void reset_after_compaction();
677
678 // Routines for managing a list of code roots (attached to the
679 // this region's RSet) that point into this heap region.
680 void add_strong_code_root(nmethod* nm);
681 void add_strong_code_root_locked(nmethod* nm);
682 void remove_strong_code_root(nmethod* nm);
683
684 // Applies blk->do_code_blob() to each of the entries in
685 // the strong code roots list for this region
686 void strong_code_roots_do(CodeBlobClosure* blk) const;
687
688 // Verify that the entries on the strong code root list for this
689 // region are live and include at least one pointer into this region.
690 void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
691
692 void print() const;
693 void print_on(outputStream* st) const;
694
695 // vo == UsePrevMarking -> use "prev" marking information,
696 // vo == UseNextMarking -> use "next" marking information
697 // vo == UseMarkWord -> use the mark word in the object header
698 //
699 // NOTE: Only the "prev" marking information is guaranteed to be
700 // consistent most of the time, so most calls to this should use
701 // vo == UsePrevMarking.
702 // Currently, there is only one case where this is called with
703 // vo == UseNextMarking, which is to verify the "next" marking
704 // information at the end of remark.
705 // Currently there is only one place where this is called with
706 // vo == UseMarkWord, which is to verify the marking during a
707 // full GC.
708 void verify(VerifyOption vo, bool *failures) const;
709
710 // Override; it uses the "prev" marking information
711 virtual void verify() const;
712
713 void verify_rem_set(VerifyOption vo, bool *failures) const;
714 void verify_rem_set() const;
715 };
716
717 // HeapRegionClosure is used for iterating over regions.
718 // Terminates the iteration when the "doHeapRegion" method returns "true".
719 class HeapRegionClosure : public StackObj {
720 friend class HeapRegionManager;
721 friend class G1CollectionSet;
722
723 bool _complete;
724 void incomplete() { _complete = false; }
725
726 public:
727 HeapRegionClosure(): _complete(true) {}
728
729 // Typically called on each region until it returns true.
730 virtual bool doHeapRegion(HeapRegion* r) = 0;
731
732 // True after iteration if the closure was applied to all heap regions
733 // and returned "false" in all cases.
734 bool complete() { return _complete; }
735 };
736
737 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP