1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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
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23 */
24
25 #ifndef SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP
26 #define SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP
27
28 #include "gc/g1/collectionSetChooser.hpp"
29 #include "gc/g1/g1CollectorState.hpp"
30 #include "gc/g1/g1InCSetState.hpp"
31 #include "gc/g1/g1MMUTracker.hpp"
32 #include "gc/g1/g1Predictions.hpp"
33 #include "gc/shared/collectorPolicy.hpp"
34
35 // A G1CollectorPolicy makes policy decisions that determine the
36 // characteristics of the collector. Examples include:
37 // * choice of collection set.
38 // * when to collect.
39
40 class HeapRegion;
41 class CollectionSetChooser;
42 class G1GCPhaseTimes;
43
44 // TraceYoungGenTime collects data on _both_ young and mixed evacuation pauses
45 // (the latter may contain non-young regions - i.e. regions that are
46 // technically in old) while TraceOldGenTime collects data about full GCs.
47 class TraceYoungGenTimeData : public CHeapObj<mtGC> {
48 private:
49 unsigned _young_pause_num;
50 unsigned _mixed_pause_num;
51
52 NumberSeq _all_stop_world_times_ms;
53 NumberSeq _all_yield_times_ms;
54
55 NumberSeq _total;
56 NumberSeq _other;
57 NumberSeq _root_region_scan_wait;
58 NumberSeq _parallel;
59 NumberSeq _ext_root_scan;
60 NumberSeq _satb_filtering;
61 NumberSeq _update_rs;
62 NumberSeq _scan_rs;
63 NumberSeq _obj_copy;
64 NumberSeq _termination;
65 NumberSeq _parallel_other;
66 NumberSeq _clear_ct;
67
68 void print_summary(const char* str, const NumberSeq* seq) const;
69 void print_summary_sd(const char* str, const NumberSeq* seq) const;
70
71 public:
72 TraceYoungGenTimeData() : _young_pause_num(0), _mixed_pause_num(0) {};
73 void record_start_collection(double time_to_stop_the_world_ms);
74 void record_yield_time(double yield_time_ms);
75 void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times);
76 void increment_young_collection_count();
77 void increment_mixed_collection_count();
78 void print() const;
79 };
80
81 class TraceOldGenTimeData : public CHeapObj<mtGC> {
82 private:
83 NumberSeq _all_full_gc_times;
84
85 public:
86 void record_full_collection(double full_gc_time_ms);
87 void print() const;
88 };
89
90 // There are three command line options related to the young gen size:
91 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
92 // just a short form for NewSize==MaxNewSize). G1 will use its internal
93 // heuristics to calculate the actual young gen size, so these options
94 // basically only limit the range within which G1 can pick a young gen
95 // size. Also, these are general options taking byte sizes. G1 will
96 // internally work with a number of regions instead. So, some rounding
97 // will occur.
98 //
99 // If nothing related to the the young gen size is set on the command
100 // line we should allow the young gen to be between G1NewSizePercent
101 // and G1MaxNewSizePercent of the heap size. This means that every time
102 // the heap size changes, the limits for the young gen size will be
103 // recalculated.
104 //
105 // If only -XX:NewSize is set we should use the specified value as the
106 // minimum size for young gen. Still using G1MaxNewSizePercent of the
107 // heap as maximum.
108 //
109 // If only -XX:MaxNewSize is set we should use the specified value as the
110 // maximum size for young gen. Still using G1NewSizePercent of the heap
111 // as minimum.
112 //
113 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
114 // No updates when the heap size changes. There is a special case when
115 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
116 // different heuristic for calculating the collection set when we do mixed
117 // collection.
118 //
119 // If only -XX:NewRatio is set we should use the specified ratio of the heap
120 // as both min and max. This will be interpreted as "fixed" just like the
121 // NewSize==MaxNewSize case above. But we will update the min and max
122 // every time the heap size changes.
123 //
124 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
125 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
126 class G1YoungGenSizer : public CHeapObj<mtGC> {
127 private:
128 enum SizerKind {
129 SizerDefaults,
130 SizerNewSizeOnly,
131 SizerMaxNewSizeOnly,
132 SizerMaxAndNewSize,
133 SizerNewRatio
134 };
135 SizerKind _sizer_kind;
136 uint _min_desired_young_length;
137 uint _max_desired_young_length;
138 bool _adaptive_size;
139 uint calculate_default_min_length(uint new_number_of_heap_regions);
140 uint calculate_default_max_length(uint new_number_of_heap_regions);
141
142 // Update the given values for minimum and maximum young gen length in regions
143 // given the number of heap regions depending on the kind of sizing algorithm.
144 void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length);
145
146 public:
147 G1YoungGenSizer();
148 // Calculate the maximum length of the young gen given the number of regions
149 // depending on the sizing algorithm.
150 uint max_young_length(uint number_of_heap_regions);
151
152 void heap_size_changed(uint new_number_of_heap_regions);
153 uint min_desired_young_length() {
154 return _min_desired_young_length;
155 }
156 uint max_desired_young_length() {
157 return _max_desired_young_length;
158 }
159 bool adaptive_young_list_length() const {
160 return _adaptive_size;
161 }
162 };
163
164 class G1CollectorPolicy: public CollectorPolicy {
165 private:
166 G1Predictions _predictor;
167
168 double get_new_prediction(TruncatedSeq const* seq) const;
169
170 // either equal to the number of parallel threads, if ParallelGCThreads
171 // has been set, or 1 otherwise
172 int _parallel_gc_threads;
173
174 // The number of GC threads currently active.
175 uintx _no_of_gc_threads;
176
177 G1MMUTracker* _mmu_tracker;
178
179 void initialize_alignments();
180 void initialize_flags();
181
182 CollectionSetChooser* _collectionSetChooser;
183
184 double _full_collection_start_sec;
185 uint _cur_collection_pause_used_regions_at_start;
186
187 // These exclude marking times.
188 TruncatedSeq* _recent_gc_times_ms;
189
190 TruncatedSeq* _concurrent_mark_remark_times_ms;
191 TruncatedSeq* _concurrent_mark_cleanup_times_ms;
192
193 TraceYoungGenTimeData _trace_young_gen_time_data;
194 TraceOldGenTimeData _trace_old_gen_time_data;
195
196 double _stop_world_start;
197
198 uint _young_list_target_length;
199 uint _young_list_fixed_length;
200
201 // The max number of regions we can extend the eden by while the GC
202 // locker is active. This should be >= _young_list_target_length;
203 uint _young_list_max_length;
204
205 SurvRateGroup* _short_lived_surv_rate_group;
206 SurvRateGroup* _survivor_surv_rate_group;
207 // add here any more surv rate groups
208
209 double _gc_overhead_perc;
210
211 double _reserve_factor;
212 uint _reserve_regions;
213
214 enum PredictionConstants {
215 TruncatedSeqLength = 10,
216 NumPrevPausesForHeuristics = 10
217 };
218
219 TruncatedSeq* _alloc_rate_ms_seq;
220 double _prev_collection_pause_end_ms;
221
222 TruncatedSeq* _rs_length_diff_seq;
223 TruncatedSeq* _cost_per_card_ms_seq;
224 TruncatedSeq* _cost_scan_hcc_seq;
225 TruncatedSeq* _young_cards_per_entry_ratio_seq;
226 TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
227 TruncatedSeq* _cost_per_entry_ms_seq;
228 TruncatedSeq* _mixed_cost_per_entry_ms_seq;
229 TruncatedSeq* _cost_per_byte_ms_seq;
230 TruncatedSeq* _constant_other_time_ms_seq;
231 TruncatedSeq* _young_other_cost_per_region_ms_seq;
232 TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
233
234 TruncatedSeq* _pending_cards_seq;
235 TruncatedSeq* _rs_lengths_seq;
236
237 TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
238
239 G1YoungGenSizer* _young_gen_sizer;
240
241 uint _eden_cset_region_length;
242 uint _survivor_cset_region_length;
243 uint _old_cset_region_length;
244
245 void init_cset_region_lengths(uint eden_cset_region_length,
246 uint survivor_cset_region_length);
247
248 uint eden_cset_region_length() const { return _eden_cset_region_length; }
249 uint survivor_cset_region_length() const { return _survivor_cset_region_length; }
250 uint old_cset_region_length() const { return _old_cset_region_length; }
251
252 uint _free_regions_at_end_of_collection;
253
254 size_t _recorded_rs_lengths;
255 size_t _max_rs_lengths;
256
257 size_t _rs_lengths_prediction;
258
259 #ifndef PRODUCT
260 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
261 #endif // PRODUCT
262
263 void adjust_concurrent_refinement(double update_rs_time,
264 double update_rs_processed_buffers,
265 double goal_ms);
266
267 uintx no_of_gc_threads() { return _no_of_gc_threads; }
268 void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
269
270 double _pause_time_target_ms;
271
272 size_t _pending_cards;
273
274 public:
275 G1Predictions& predictor() { return _predictor; }
276
277 // Accessors
278
279 void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
280 hr->set_eden();
281 hr->install_surv_rate_group(_short_lived_surv_rate_group);
282 hr->set_young_index_in_cset(young_index_in_cset);
283 }
284
285 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
286 assert(hr->is_survivor(), "pre-condition");
287 hr->install_surv_rate_group(_survivor_surv_rate_group);
288 hr->set_young_index_in_cset(young_index_in_cset);
289 }
290
291 #ifndef PRODUCT
292 bool verify_young_ages();
293 #endif // PRODUCT
294
295 void record_max_rs_lengths(size_t rs_lengths) {
296 _max_rs_lengths = rs_lengths;
297 }
298
299 size_t predict_rs_length_diff() const;
300
301 double predict_alloc_rate_ms() const;
302
303 double predict_cost_per_card_ms() const;
304
305 double predict_scan_hcc_ms() const;
306
307 double predict_rs_update_time_ms(size_t pending_cards) const;
308
309 double predict_young_cards_per_entry_ratio() const;
310
311 double predict_mixed_cards_per_entry_ratio() const;
312
313 size_t predict_young_card_num(size_t rs_length) const;
314
315 size_t predict_non_young_card_num(size_t rs_length) const;
316
317 double predict_rs_scan_time_ms(size_t card_num) const;
318
319 double predict_mixed_rs_scan_time_ms(size_t card_num) const;
320
321 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
322
323 double predict_object_copy_time_ms(size_t bytes_to_copy) const;
324
325 double predict_constant_other_time_ms() const;
326
327 double predict_young_other_time_ms(size_t young_num) const;
328
329 double predict_non_young_other_time_ms(size_t non_young_num) const;
330
331 double predict_base_elapsed_time_ms(size_t pending_cards) const;
332 double predict_base_elapsed_time_ms(size_t pending_cards,
333 size_t scanned_cards) const;
334 size_t predict_bytes_to_copy(HeapRegion* hr) const;
335 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
336
337 void set_recorded_rs_lengths(size_t rs_lengths);
338
339 uint cset_region_length() const { return young_cset_region_length() +
340 old_cset_region_length(); }
341 uint young_cset_region_length() const { return eden_cset_region_length() +
342 survivor_cset_region_length(); }
343
344 double predict_survivor_regions_evac_time() const;
345
346 bool should_update_surv_rate_group_predictors() {
347 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
348 }
349
350 void cset_regions_freed() {
351 bool update = should_update_surv_rate_group_predictors();
352
353 _short_lived_surv_rate_group->all_surviving_words_recorded(update);
354 _survivor_surv_rate_group->all_surviving_words_recorded(update);
355 }
356
357 G1MMUTracker* mmu_tracker() {
358 return _mmu_tracker;
359 }
360
361 const G1MMUTracker* mmu_tracker() const {
362 return _mmu_tracker;
363 }
364
365 double max_pause_time_ms() const {
366 return _mmu_tracker->max_gc_time() * 1000.0;
367 }
368
369 double predict_remark_time_ms() const;
370
371 double predict_cleanup_time_ms() const;
372
373 // Returns an estimate of the survival rate of the region at yg-age
374 // "yg_age".
375 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
376
377 double predict_yg_surv_rate(int age) const;
378
379 double accum_yg_surv_rate_pred(int age) const;
380
381 private:
382 // Statistics kept per GC stoppage, pause or full.
383 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
384
385 // Add a new GC of the given duration and end time to the record.
386 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
387
388 // The head of the list (via "next_in_collection_set()") representing the
389 // current collection set. Set from the incrementally built collection
390 // set at the start of the pause.
391 HeapRegion* _collection_set;
392
393 // The number of bytes in the collection set before the pause. Set from
394 // the incrementally built collection set at the start of an evacuation
395 // pause, and incremented in finalize_old_cset_part() when adding old regions
396 // (if any) to the collection set.
397 size_t _collection_set_bytes_used_before;
398
399 // The number of bytes copied during the GC.
400 size_t _bytes_copied_during_gc;
401
402 // The associated information that is maintained while the incremental
403 // collection set is being built with young regions. Used to populate
404 // the recorded info for the evacuation pause.
405
406 enum CSetBuildType {
407 Active, // We are actively building the collection set
408 Inactive // We are not actively building the collection set
409 };
410
411 CSetBuildType _inc_cset_build_state;
412
413 // The head of the incrementally built collection set.
414 HeapRegion* _inc_cset_head;
415
416 // The tail of the incrementally built collection set.
417 HeapRegion* _inc_cset_tail;
418
419 // The number of bytes in the incrementally built collection set.
420 // Used to set _collection_set_bytes_used_before at the start of
421 // an evacuation pause.
422 size_t _inc_cset_bytes_used_before;
423
424 // Used to record the highest end of heap region in collection set
425 HeapWord* _inc_cset_max_finger;
426
427 // The RSet lengths recorded for regions in the CSet. It is updated
428 // by the thread that adds a new region to the CSet. We assume that
429 // only one thread can be allocating a new CSet region (currently,
430 // it does so after taking the Heap_lock) hence no need to
431 // synchronize updates to this field.
432 size_t _inc_cset_recorded_rs_lengths;
433
434 // A concurrent refinement thread periodically samples the young
435 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
436 // the RSets grow. Instead of having to synchronize updates to that
437 // field we accumulate them in this field and add it to
438 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
439 ssize_t _inc_cset_recorded_rs_lengths_diffs;
440
441 // The predicted elapsed time it will take to collect the regions in
442 // the CSet. This is updated by the thread that adds a new region to
443 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
444 // MT-safety assumptions.
445 double _inc_cset_predicted_elapsed_time_ms;
446
447 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
448 double _inc_cset_predicted_elapsed_time_ms_diffs;
449
450 // Stash a pointer to the g1 heap.
451 G1CollectedHeap* _g1;
452
453 G1GCPhaseTimes* _phase_times;
454
455 // The ratio of gc time to elapsed time, computed over recent pauses.
456 double _recent_avg_pause_time_ratio;
457
458 double recent_avg_pause_time_ratio() const {
459 return _recent_avg_pause_time_ratio;
460 }
461
462 // This set of variables tracks the collector efficiency, in order to
463 // determine whether we should initiate a new marking.
464 double _cur_mark_stop_world_time_ms;
465 double _mark_remark_start_sec;
466 double _mark_cleanup_start_sec;
467
468 void update_young_list_max_and_target_length();
469 void update_young_list_max_and_target_length(size_t rs_lengths);
470
471 // Update the young list target length either by setting it to the
472 // desired fixed value or by calculating it using G1's pause
473 // prediction model. If no rs_lengths parameter is passed, predict
474 // the RS lengths using the prediction model, otherwise use the
475 // given rs_lengths as the prediction.
476 void update_young_list_target_length();
477 void update_young_list_target_length(size_t rs_lengths);
478
479 // Calculate and return the minimum desired young list target
480 // length. This is the minimum desired young list length according
481 // to the user's inputs.
482 uint calculate_young_list_desired_min_length(uint base_min_length) const;
483
484 // Calculate and return the maximum desired young list target
485 // length. This is the maximum desired young list length according
486 // to the user's inputs.
487 uint calculate_young_list_desired_max_length() const;
488
489 // Calculate and return the maximum young list target length that
490 // can fit into the pause time goal. The parameters are: rs_lengths
491 // represent the prediction of how large the young RSet lengths will
492 // be, base_min_length is the already existing number of regions in
493 // the young list, min_length and max_length are the desired min and
494 // max young list length according to the user's inputs.
495 uint calculate_young_list_target_length(size_t rs_lengths,
496 uint base_min_length,
497 uint desired_min_length,
498 uint desired_max_length) const;
499
500 uint bounded_young_list_target_length(size_t rs_lengths) const;
501
502 void update_rs_lengths_prediction();
503 void update_rs_lengths_prediction(size_t prediction);
504
505 // Calculate and return chunk size (in number of regions) for parallel
506 // concurrent mark cleanup.
507 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
508
509 // Check whether a given young length (young_length) fits into the
510 // given target pause time and whether the prediction for the amount
511 // of objects to be copied for the given length will fit into the
512 // given free space (expressed by base_free_regions). It is used by
513 // calculate_young_list_target_length().
514 bool predict_will_fit(uint young_length, double base_time_ms,
515 uint base_free_regions, double target_pause_time_ms) const;
516
517 // Calculate the minimum number of old regions we'll add to the CSet
518 // during a mixed GC.
519 uint calc_min_old_cset_length() const;
520
521 // Calculate the maximum number of old regions we'll add to the CSet
522 // during a mixed GC.
523 uint calc_max_old_cset_length() const;
524
525 // Returns the given amount of uncollected reclaimable space
526 // as a percentage of the current heap capacity.
527 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
528
529 public:
530
531 G1CollectorPolicy();
532
533 virtual G1CollectorPolicy* as_g1_policy() { return this; }
534
535 G1CollectorState* collector_state() const;
536
537 G1GCPhaseTimes* phase_times() const { return _phase_times; }
538
539 // Check the current value of the young list RSet lengths and
540 // compare it against the last prediction. If the current value is
541 // higher, recalculate the young list target length prediction.
542 void revise_young_list_target_length_if_necessary();
543
544 // This should be called after the heap is resized.
545 void record_new_heap_size(uint new_number_of_regions);
546
547 void init();
548
549 // Create jstat counters for the policy.
550 virtual void initialize_gc_policy_counters();
551
552 virtual HeapWord* mem_allocate_work(size_t size,
553 bool is_tlab,
554 bool* gc_overhead_limit_was_exceeded);
555
556 // This method controls how a collector handles one or more
557 // of its generations being fully allocated.
558 virtual HeapWord* satisfy_failed_allocation(size_t size,
559 bool is_tlab);
560
561 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
562
563 // Record the start and end of an evacuation pause.
564 void record_collection_pause_start(double start_time_sec);
565 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned);
566
567 // Record the start and end of a full collection.
568 void record_full_collection_start();
569 void record_full_collection_end();
570
571 // Must currently be called while the world is stopped.
572 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
573
574 // Record start and end of remark.
575 void record_concurrent_mark_remark_start();
576 void record_concurrent_mark_remark_end();
577
578 // Record start, end, and completion of cleanup.
579 void record_concurrent_mark_cleanup_start();
580 void record_concurrent_mark_cleanup_end();
581 void record_concurrent_mark_cleanup_completed();
582
583 // Records the information about the heap size for reporting in
584 // print_detailed_heap_transition
585 void record_heap_size_info_at_start(bool full);
586
587 // Print heap sizing transition (with less and more detail).
588
589 void print_heap_transition(size_t bytes_before) const;
590 void print_heap_transition() const;
591 void print_detailed_heap_transition(bool full = false) const;
592
593 void record_stop_world_start();
594 void record_concurrent_pause();
595
596 // Record how much space we copied during a GC. This is typically
597 // called when a GC alloc region is being retired.
598 void record_bytes_copied_during_gc(size_t bytes) {
599 _bytes_copied_during_gc += bytes;
600 }
601
602 // The amount of space we copied during a GC.
603 size_t bytes_copied_during_gc() const {
604 return _bytes_copied_during_gc;
605 }
606
607 size_t collection_set_bytes_used_before() const {
608 return _collection_set_bytes_used_before;
609 }
610
611 // Determine whether there are candidate regions so that the
612 // next GC should be mixed. The two action strings are used
613 // in the ergo output when the method returns true or false.
614 bool next_gc_should_be_mixed(const char* true_action_str,
615 const char* false_action_str) const;
616
617 // Choose a new collection set. Marks the chosen regions as being
618 // "in_collection_set", and links them together. The head and number of
619 // the collection set are available via access methods.
620 double finalize_young_cset_part(double target_pause_time_ms);
621 virtual void finalize_old_cset_part(double time_remaining_ms);
622
623 // The head of the list (via "next_in_collection_set()") representing the
624 // current collection set.
625 HeapRegion* collection_set() { return _collection_set; }
626
627 void clear_collection_set() { _collection_set = NULL; }
628
629 // Add old region "hr" to the CSet.
630 void add_old_region_to_cset(HeapRegion* hr);
631
632 // Incremental CSet Support
633
634 // The head of the incrementally built collection set.
635 HeapRegion* inc_cset_head() { return _inc_cset_head; }
636
637 // The tail of the incrementally built collection set.
638 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
639
640 // Initialize incremental collection set info.
641 void start_incremental_cset_building();
642
643 // Perform any final calculations on the incremental CSet fields
644 // before we can use them.
645 void finalize_incremental_cset_building();
646
647 void clear_incremental_cset() {
648 _inc_cset_head = NULL;
649 _inc_cset_tail = NULL;
650 }
651
652 // Stop adding regions to the incremental collection set
653 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
654
655 // Add information about hr to the aggregated information for the
656 // incrementally built collection set.
657 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
658
659 // Update information about hr in the aggregated information for
660 // the incrementally built collection set.
661 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
662
663 private:
664 // Update the incremental cset information when adding a region
665 // (should not be called directly).
666 void add_region_to_incremental_cset_common(HeapRegion* hr);
667
668 public:
669 // Add hr to the LHS of the incremental collection set.
670 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
671
672 // Add hr to the RHS of the incremental collection set.
673 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
674
675 #ifndef PRODUCT
676 void print_collection_set(HeapRegion* list_head, outputStream* st);
677 #endif // !PRODUCT
678
679 // This sets the initiate_conc_mark_if_possible() flag to start a
680 // new cycle, as long as we are not already in one. It's best if it
681 // is called during a safepoint when the test whether a cycle is in
682 // progress or not is stable.
683 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
684
685 // This is called at the very beginning of an evacuation pause (it
686 // has to be the first thing that the pause does). If
687 // initiate_conc_mark_if_possible() is true, and the concurrent
688 // marking thread has completed its work during the previous cycle,
689 // it will set during_initial_mark_pause() to so that the pause does
690 // the initial-mark work and start a marking cycle.
691 void decide_on_conc_mark_initiation();
692
693 // If an expansion would be appropriate, because recent GC overhead had
694 // exceeded the desired limit, return an amount to expand by.
695 virtual size_t expansion_amount() const;
696
697 // Print tracing information.
698 void print_tracing_info() const;
699
700 // Print stats on young survival ratio
701 void print_yg_surv_rate_info() const;
702
703 void finished_recalculating_age_indexes(bool is_survivors) {
704 if (is_survivors) {
705 _survivor_surv_rate_group->finished_recalculating_age_indexes();
706 } else {
707 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
708 }
709 // do that for any other surv rate groups
710 }
711
712 size_t young_list_target_length() const { return _young_list_target_length; }
713
714 bool is_young_list_full() const;
715
716 bool can_expand_young_list() const;
717
718 uint young_list_max_length() const {
719 return _young_list_max_length;
720 }
721
722 bool adaptive_young_list_length() const {
723 return _young_gen_sizer->adaptive_young_list_length();
724 }
725
726 private:
727 //
728 // Survivor regions policy.
729 //
730
731 // Current tenuring threshold, set to 0 if the collector reaches the
732 // maximum amount of survivors regions.
733 uint _tenuring_threshold;
734
735 // The limit on the number of regions allocated for survivors.
736 uint _max_survivor_regions;
737
738 // For reporting purposes.
739 // The value of _heap_bytes_before_gc is also used to calculate
740 // the cost of copying.
741
742 size_t _eden_used_bytes_before_gc; // Eden occupancy before GC
743 size_t _survivor_used_bytes_before_gc; // Survivor occupancy before GC
744 size_t _heap_used_bytes_before_gc; // Heap occupancy before GC
745 size_t _metaspace_used_bytes_before_gc; // Metaspace occupancy before GC
746
747 size_t _eden_capacity_bytes_before_gc; // Eden capacity before GC
748 size_t _heap_capacity_bytes_before_gc; // Heap capacity before GC
749
750 // The amount of survivor regions after a collection.
751 uint _recorded_survivor_regions;
752 // List of survivor regions.
753 HeapRegion* _recorded_survivor_head;
754 HeapRegion* _recorded_survivor_tail;
755
756 ageTable _survivors_age_table;
757
758 public:
759 uint tenuring_threshold() const { return _tenuring_threshold; }
760
761 static const uint REGIONS_UNLIMITED = (uint) -1;
762
763 uint max_regions(InCSetState dest) const {
764 switch (dest.value()) {
765 case InCSetState::Young:
766 return _max_survivor_regions;
767 case InCSetState::Old:
768 return REGIONS_UNLIMITED;
769 default:
770 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value());
771 break;
772 }
773 // keep some compilers happy
774 return 0;
775 }
776
777 void note_start_adding_survivor_regions() {
778 _survivor_surv_rate_group->start_adding_regions();
779 }
780
781 void note_stop_adding_survivor_regions() {
782 _survivor_surv_rate_group->stop_adding_regions();
783 }
784
785 void record_survivor_regions(uint regions,
786 HeapRegion* head,
787 HeapRegion* tail) {
788 _recorded_survivor_regions = regions;
789 _recorded_survivor_head = head;
790 _recorded_survivor_tail = tail;
791 }
792
793 uint recorded_survivor_regions() const {
794 return _recorded_survivor_regions;
795 }
796
797 void record_age_table(ageTable* age_table) {
798 _survivors_age_table.merge(age_table);
799 }
800
801 void update_max_gc_locker_expansion();
802
803 // Calculates survivor space parameters.
804 void update_survivors_policy();
805
806 virtual void post_heap_initialize();
807 };
808
809 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP