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.
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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).
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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/g1GCPhaseTimes.hpp"
31 #include "gc/g1/g1InCSetState.hpp"
32 #include "gc/g1/g1MMUTracker.hpp"
33 #include "gc/g1/g1Predictions.hpp"
34 #include "gc/shared/collectorPolicy.hpp"
35
36 // A G1CollectorPolicy makes policy decisions that determine the
37 // characteristics of the collector. Examples include:
38 // * choice of collection set.
39 // * when to collect.
40
41 class HeapRegion;
42 class CollectionSetChooser;
43 class G1IHOPControl;
44
45 // TraceYoungGenTime collects data on _both_ young and mixed evacuation pauses
46 // (the latter may contain non-young regions - i.e. regions that are
47 // technically in old) while TraceOldGenTime collects data about full GCs.
48 class TraceYoungGenTimeData : public CHeapObj<mtGC> {
49 private:
50 unsigned _young_pause_num;
51 unsigned _mixed_pause_num;
52
53 NumberSeq _all_stop_world_times_ms;
54 NumberSeq _all_yield_times_ms;
55
56 NumberSeq _total;
57 NumberSeq _other;
58 NumberSeq _root_region_scan_wait;
59 NumberSeq _parallel;
60 NumberSeq _ext_root_scan;
61 NumberSeq _satb_filtering;
62 NumberSeq _update_rs;
63 NumberSeq _scan_rs;
64 NumberSeq _obj_copy;
65 NumberSeq _termination;
66 NumberSeq _parallel_other;
67 NumberSeq _clear_ct;
68
69 void print_summary(const char* str, const NumberSeq* seq) const;
70 void print_summary_sd(const char* str, const NumberSeq* seq) const;
71
72 public:
73 TraceYoungGenTimeData() : _young_pause_num(0), _mixed_pause_num(0) {};
74 void record_start_collection(double time_to_stop_the_world_ms);
75 void record_yield_time(double yield_time_ms);
76 void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times);
77 void increment_young_collection_count();
78 void increment_mixed_collection_count();
79 void print() const;
80 };
81
82 class TraceOldGenTimeData : public CHeapObj<mtGC> {
83 private:
84 NumberSeq _all_full_gc_times;
85
86 public:
87 void record_full_collection(double full_gc_time_ms);
88 void print() const;
89 };
90
91 // There are three command line options related to the young gen size:
92 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
93 // just a short form for NewSize==MaxNewSize). G1 will use its internal
94 // heuristics to calculate the actual young gen size, so these options
95 // basically only limit the range within which G1 can pick a young gen
96 // size. Also, these are general options taking byte sizes. G1 will
97 // internally work with a number of regions instead. So, some rounding
98 // will occur.
99 //
100 // If nothing related to the the young gen size is set on the command
101 // line we should allow the young gen to be between G1NewSizePercent
102 // and G1MaxNewSizePercent of the heap size. This means that every time
103 // the heap size changes, the limits for the young gen size will be
104 // recalculated.
105 //
106 // If only -XX:NewSize is set we should use the specified value as the
107 // minimum size for young gen. Still using G1MaxNewSizePercent of the
108 // heap as maximum.
109 //
110 // If only -XX:MaxNewSize is set we should use the specified value as the
111 // maximum size for young gen. Still using G1NewSizePercent of the heap
112 // as minimum.
113 //
114 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
115 // No updates when the heap size changes. There is a special case when
116 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
117 // different heuristic for calculating the collection set when we do mixed
118 // collection.
119 //
120 // If only -XX:NewRatio is set we should use the specified ratio of the heap
121 // as both min and max. This will be interpreted as "fixed" just like the
122 // NewSize==MaxNewSize case above. But we will update the min and max
123 // every time the heap size changes.
124 //
125 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
126 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
127 class G1YoungGenSizer : public CHeapObj<mtGC> {
128 private:
129 enum SizerKind {
130 SizerDefaults,
131 SizerNewSizeOnly,
132 SizerMaxNewSizeOnly,
133 SizerMaxAndNewSize,
134 SizerNewRatio
135 };
136 SizerKind _sizer_kind;
137 uint _min_desired_young_length;
138 uint _max_desired_young_length;
139 bool _adaptive_size;
140 uint calculate_default_min_length(uint new_number_of_heap_regions);
141 uint calculate_default_max_length(uint new_number_of_heap_regions);
142
143 // Update the given values for minimum and maximum young gen length in regions
144 // given the number of heap regions depending on the kind of sizing algorithm.
145 void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length);
146
147 public:
148 G1YoungGenSizer();
149 // Calculate the maximum length of the young gen given the number of regions
150 // depending on the sizing algorithm.
151 uint max_young_length(uint number_of_heap_regions);
152
153 void heap_size_changed(uint new_number_of_heap_regions);
154 uint min_desired_young_length() {
155 return _min_desired_young_length;
156 }
157 uint max_desired_young_length() {
158 return _max_desired_young_length;
159 }
160 bool adaptive_young_list_length() const {
161 return _adaptive_size;
162 }
163 };
164
165 class G1CollectorPolicy: public CollectorPolicy {
166 private:
167 G1IHOPControl* _ihop_control;
168
169 G1IHOPControl* create_ihop_control() const;
170 void update_ihop_statistics(double marking_to_mixed_time,
171 double mutator_time_s,
172 size_t mutator_alloc_bytes,
173 size_t young_gen_size);
174 void report_ihop_statistics();
175
176 G1Predictions _predictor;
177
178 double get_new_prediction(TruncatedSeq const* seq) const;
179
180 // either equal to the number of parallel threads, if ParallelGCThreads
181 // has been set, or 1 otherwise
182 int _parallel_gc_threads;
183
184 // The number of GC threads currently active.
185 uintx _no_of_gc_threads;
186
187 G1MMUTracker* _mmu_tracker;
188
189 void initialize_alignments();
190 void initialize_flags();
191
192 CollectionSetChooser* _collectionSetChooser;
193
194 double _full_collection_start_sec;
195 uint _cur_collection_pause_used_regions_at_start;
196
197 // These exclude marking times.
198 TruncatedSeq* _recent_gc_times_ms;
199
200 TruncatedSeq* _concurrent_mark_remark_times_ms;
201 TruncatedSeq* _concurrent_mark_cleanup_times_ms;
202
203 TraceYoungGenTimeData _trace_young_gen_time_data;
204 TraceOldGenTimeData _trace_old_gen_time_data;
205
206 double _stop_world_start;
207
208 uint _young_list_target_length;
209 uint _young_list_fixed_length;
210
211 // The max number of regions we can extend the eden by while the GC
212 // locker is active. This should be >= _young_list_target_length;
213 uint _young_list_max_length;
214
215 SurvRateGroup* _short_lived_surv_rate_group;
216 SurvRateGroup* _survivor_surv_rate_group;
217 // add here any more surv rate groups
218
219 double _gc_overhead_perc;
220
221 double _reserve_factor;
222 uint _reserve_regions;
223
224 enum PredictionConstants {
225 TruncatedSeqLength = 10,
226 NumPrevPausesForHeuristics = 10
227 };
228
229 TruncatedSeq* _alloc_rate_ms_seq;
230 double _prev_collection_pause_end_ms;
231
232 TruncatedSeq* _rs_length_diff_seq;
233 TruncatedSeq* _cost_per_card_ms_seq;
234 TruncatedSeq* _cost_scan_hcc_seq;
235 TruncatedSeq* _young_cards_per_entry_ratio_seq;
236 TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
237 TruncatedSeq* _cost_per_entry_ms_seq;
238 TruncatedSeq* _mixed_cost_per_entry_ms_seq;
239 TruncatedSeq* _cost_per_byte_ms_seq;
240 TruncatedSeq* _constant_other_time_ms_seq;
241 TruncatedSeq* _young_other_cost_per_region_ms_seq;
242 TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
243
244 TruncatedSeq* _pending_cards_seq;
245 TruncatedSeq* _rs_lengths_seq;
246
247 TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
248
249 G1YoungGenSizer* _young_gen_sizer;
250
251 uint _eden_cset_region_length;
252 uint _survivor_cset_region_length;
253 uint _old_cset_region_length;
254
255 void init_cset_region_lengths(uint eden_cset_region_length,
256 uint survivor_cset_region_length);
257
258 uint eden_cset_region_length() const { return _eden_cset_region_length; }
259 uint survivor_cset_region_length() const { return _survivor_cset_region_length; }
260 uint old_cset_region_length() const { return _old_cset_region_length; }
261
262 uint _free_regions_at_end_of_collection;
263
264 size_t _recorded_rs_lengths;
265 size_t _max_rs_lengths;
266
267 size_t _rs_lengths_prediction;
268
269 #ifndef PRODUCT
270 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
271 #endif // PRODUCT
272
273 void adjust_concurrent_refinement(double update_rs_time,
274 double update_rs_processed_buffers,
275 double goal_ms);
276
277 uintx no_of_gc_threads() { return _no_of_gc_threads; }
278 void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
279
280 double _pause_time_target_ms;
281
282 size_t _pending_cards;
283
284 // The amount of allocated bytes in old gen during the last mutator and the following
285 // young GC phase.
286 size_t _last_old_allocated_bytes;
287
288 // Used to track time from the end of initial mark to the first mixed GC.
289 class InitialMarkToMixedTimeTracker {
290 private:
291 bool _active;
292 double _initial_mark_end_time;
293 double _mixed_start_time;
294 double _total_pause_time;
295
296 double wall_time() const {
297 return _mixed_start_time - _initial_mark_end_time;
298 }
299 public:
300 InitialMarkToMixedTimeTracker() { reset(); }
301
302 void record_initial_mark_end(double end_time) {
303 assert(!_active, "Initial mark out of order.");
304 _initial_mark_end_time = end_time;
305 _active = true;
306 }
307
308 void record_mixed_gc_start(double start_time) {
309 if (_active) {
310 _mixed_start_time = start_time;
311 _active = false;
312 }
313 }
314
315 double last_marking_time() {
316 assert(has_result(), "Do not have all measurements yet.");
317 double result = (_mixed_start_time - _initial_mark_end_time) - _total_pause_time;
318 reset();
319 return result;
320 }
321
322 void reset() {
323 _active = false;
324 _total_pause_time = 0.0;
325 _initial_mark_end_time = -1.0;
326 _mixed_start_time = -1.0;
327 }
328
329 void add_pause(double time) {
330 if (_active) {
331 _total_pause_time += time;
332 }
333 }
334
335 bool has_result() const { return _mixed_start_time > 0.0 && _initial_mark_end_time > 0.0; }
336 };
337
338 InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
339 public:
340 G1Predictions& predictor() { return _predictor; }
341
342 // Add the given number of bytes to the total number of allocated bytes in the old gen.
343 void add_last_old_allocated_bytes(size_t bytes) { _last_old_allocated_bytes += bytes; }
344
345 // Accessors
346
347 void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
348 hr->set_eden();
349 hr->install_surv_rate_group(_short_lived_surv_rate_group);
350 hr->set_young_index_in_cset(young_index_in_cset);
351 }
352
353 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
354 assert(hr->is_survivor(), "pre-condition");
355 hr->install_surv_rate_group(_survivor_surv_rate_group);
356 hr->set_young_index_in_cset(young_index_in_cset);
357 }
358
359 #ifndef PRODUCT
360 bool verify_young_ages();
361 #endif // PRODUCT
362
363 void record_max_rs_lengths(size_t rs_lengths) {
364 _max_rs_lengths = rs_lengths;
365 }
366
367 size_t predict_rs_length_diff() const;
368
369 double predict_alloc_rate_ms() const;
370
371 double predict_cost_per_card_ms() const;
372
373 double predict_scan_hcc_ms() const;
374
375 double predict_rs_update_time_ms(size_t pending_cards) const;
376
377 double predict_young_cards_per_entry_ratio() const;
378
379 double predict_mixed_cards_per_entry_ratio() const;
380
381 size_t predict_young_card_num(size_t rs_length) const;
382
383 size_t predict_non_young_card_num(size_t rs_length) const;
384
385 double predict_rs_scan_time_ms(size_t card_num) const;
386
387 double predict_mixed_rs_scan_time_ms(size_t card_num) const;
388
389 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
390
391 double predict_object_copy_time_ms(size_t bytes_to_copy) const;
392
393 double predict_constant_other_time_ms() const;
394
395 double predict_young_other_time_ms(size_t young_num) const;
396
397 double predict_non_young_other_time_ms(size_t non_young_num) const;
398
399 double predict_base_elapsed_time_ms(size_t pending_cards) const;
400 double predict_base_elapsed_time_ms(size_t pending_cards,
401 size_t scanned_cards) const;
402 size_t predict_bytes_to_copy(HeapRegion* hr) const;
403 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
404
405 void set_recorded_rs_lengths(size_t rs_lengths);
406
407 uint cset_region_length() const { return young_cset_region_length() +
408 old_cset_region_length(); }
409 uint young_cset_region_length() const { return eden_cset_region_length() +
410 survivor_cset_region_length(); }
411
412 double predict_survivor_regions_evac_time() const;
413
414 bool should_update_surv_rate_group_predictors() {
415 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
416 }
417
418 void cset_regions_freed() {
419 bool update = should_update_surv_rate_group_predictors();
420
421 _short_lived_surv_rate_group->all_surviving_words_recorded(update);
422 _survivor_surv_rate_group->all_surviving_words_recorded(update);
423 }
424
425 G1MMUTracker* mmu_tracker() {
426 return _mmu_tracker;
427 }
428
429 const G1MMUTracker* mmu_tracker() const {
430 return _mmu_tracker;
431 }
432
433 double max_pause_time_ms() const {
434 return _mmu_tracker->max_gc_time() * 1000.0;
435 }
436
437 double predict_remark_time_ms() const;
438
439 double predict_cleanup_time_ms() const;
440
441 // Returns an estimate of the survival rate of the region at yg-age
442 // "yg_age".
443 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
444
445 double predict_yg_surv_rate(int age) const;
446
447 double accum_yg_surv_rate_pred(int age) const;
448
449 protected:
450 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
451 virtual double other_time_ms(double pause_time_ms) const;
452
453 double young_other_time_ms() const;
454 double non_young_other_time_ms() const;
455 double constant_other_time_ms(double pause_time_ms) const;
456
457 private:
458 // Statistics kept per GC stoppage, pause or full.
459 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
460
461 // Add a new GC of the given duration and end time to the record.
462 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
463
464 // The head of the list (via "next_in_collection_set()") representing the
465 // current collection set. Set from the incrementally built collection
466 // set at the start of the pause.
467 HeapRegion* _collection_set;
468
469 // The number of bytes in the collection set before the pause. Set from
470 // the incrementally built collection set at the start of an evacuation
471 // pause, and incremented in finalize_old_cset_part() when adding old regions
472 // (if any) to the collection set.
473 size_t _collection_set_bytes_used_before;
474
475 // The number of bytes copied during the GC.
476 size_t _bytes_copied_during_gc;
477
478 // The associated information that is maintained while the incremental
479 // collection set is being built with young regions. Used to populate
480 // the recorded info for the evacuation pause.
481
482 enum CSetBuildType {
483 Active, // We are actively building the collection set
484 Inactive // We are not actively building the collection set
485 };
486
487 CSetBuildType _inc_cset_build_state;
488
489 // The head of the incrementally built collection set.
490 HeapRegion* _inc_cset_head;
491
492 // The tail of the incrementally built collection set.
493 HeapRegion* _inc_cset_tail;
494
495 // The number of bytes in the incrementally built collection set.
496 // Used to set _collection_set_bytes_used_before at the start of
497 // an evacuation pause.
498 size_t _inc_cset_bytes_used_before;
499
500 // Used to record the highest end of heap region in collection set
501 HeapWord* _inc_cset_max_finger;
502
503 // The RSet lengths recorded for regions in the CSet. It is updated
504 // by the thread that adds a new region to the CSet. We assume that
505 // only one thread can be allocating a new CSet region (currently,
506 // it does so after taking the Heap_lock) hence no need to
507 // synchronize updates to this field.
508 size_t _inc_cset_recorded_rs_lengths;
509
510 // A concurrent refinement thread periodically samples the young
511 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
512 // the RSets grow. Instead of having to synchronize updates to that
513 // field we accumulate them in this field and add it to
514 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
515 ssize_t _inc_cset_recorded_rs_lengths_diffs;
516
517 // The predicted elapsed time it will take to collect the regions in
518 // the CSet. This is updated by the thread that adds a new region to
519 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
520 // MT-safety assumptions.
521 double _inc_cset_predicted_elapsed_time_ms;
522
523 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
524 double _inc_cset_predicted_elapsed_time_ms_diffs;
525
526 // Stash a pointer to the g1 heap.
527 G1CollectedHeap* _g1;
528
529 G1GCPhaseTimes* _phase_times;
530
531 // The ratio of gc time to elapsed time, computed over recent pauses.
532 double _recent_avg_pause_time_ratio;
533
534 double recent_avg_pause_time_ratio() const {
535 return _recent_avg_pause_time_ratio;
536 }
537
538 // This set of variables tracks the collector efficiency, in order to
539 // determine whether we should initiate a new marking.
540 double _cur_mark_stop_world_time_ms;
541 double _mark_remark_start_sec;
542 double _mark_cleanup_start_sec;
543
544 void update_young_list_max_and_target_length(size_t* unbounded_target_length = NULL);
545 void update_young_list_max_and_target_length(size_t rs_lengths, size_t* unbounded_target_length = NULL);
546
547 // Update the young list target length either by setting it to the
548 // desired fixed value or by calculating it using G1's pause
549 // prediction model. If no rs_lengths parameter is passed, predict
550 // the RS lengths using the prediction model, otherwise use the
551 // given rs_lengths as the prediction.
552 void update_young_list_target_length();
553 void update_young_list_target_length(size_t rs_lengths, size_t* unbounded_target_length = NULL);
554
555 // Calculate and return the minimum desired young list target
556 // length. This is the minimum desired young list length according
557 // to the user's inputs.
558 uint calculate_young_list_desired_min_length(uint base_min_length) const;
559
560 // Calculate and return the maximum desired young list target
561 // length. This is the maximum desired young list length according
562 // to the user's inputs.
563 uint calculate_young_list_desired_max_length() const;
564
565 // Calculate and return the maximum young list target length that
566 // can fit into the pause time goal. The parameters are: rs_lengths
567 // represent the prediction of how large the young RSet lengths will
568 // be, base_min_length is the already existing number of regions in
569 // the young list, min_length and max_length are the desired min and
570 // max young list length according to the user's inputs.
571 uint calculate_young_list_target_length(size_t rs_lengths,
572 uint base_min_length,
573 uint desired_min_length,
574 uint desired_max_length) const;
575
576 uint bounded_young_list_target_length(size_t rs_lengths, size_t* unbounded_target_length = NULL) const;
577
578 void update_rs_lengths_prediction();
579 void update_rs_lengths_prediction(size_t prediction);
580
581 // Calculate and return chunk size (in number of regions) for parallel
582 // concurrent mark cleanup.
583 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
584
585 // Check whether a given young length (young_length) fits into the
586 // given target pause time and whether the prediction for the amount
587 // of objects to be copied for the given length will fit into the
588 // given free space (expressed by base_free_regions). It is used by
589 // calculate_young_list_target_length().
590 bool predict_will_fit(uint young_length, double base_time_ms,
591 uint base_free_regions, double target_pause_time_ms) const;
592
593 // Calculate the minimum number of old regions we'll add to the CSet
594 // during a mixed GC.
595 uint calc_min_old_cset_length() const;
596
597 // Calculate the maximum number of old regions we'll add to the CSet
598 // during a mixed GC.
599 uint calc_max_old_cset_length() const;
600
601 // Returns the given amount of uncollected reclaimable space
602 // as a percentage of the current heap capacity.
603 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
604
605 // Sets up marking if proper conditions are met.
606 void maybe_start_marking();
607
608 // The kind of STW pause.
609 enum PauseKind {
610 FullGC,
611 YoungOnlyGC,
612 MixedGC,
613 LastYoungGC,
614 InitialMarkGC,
615 Cleanup,
616 Remark
617 };
618
619 // Calculate PauseKind from internal state.
620 PauseKind young_gc_pause_kind() const;
621 // Record the given STW pause with the given start and end times (in s).
622 void record_pause(PauseKind kind, double start, double end);
623 // Indicate that we aborted marking before doing any mixed GCs.
624 void abort_time_to_mixed_tracking();
625 public:
626
627 G1CollectorPolicy();
628
629 virtual ~G1CollectorPolicy();
630
631 virtual G1CollectorPolicy* as_g1_policy() { return this; }
632
633 G1CollectorState* collector_state() const;
634
635 G1GCPhaseTimes* phase_times() const { return _phase_times; }
636
637 // Check the current value of the young list RSet lengths and
638 // compare it against the last prediction. If the current value is
639 // higher, recalculate the young list target length prediction.
640 void revise_young_list_target_length_if_necessary();
641
642 // This should be called after the heap is resized.
643 void record_new_heap_size(uint new_number_of_regions);
644
645 void init();
646
647 virtual void note_gc_start(uint num_active_workers);
648
649 // Create jstat counters for the policy.
650 virtual void initialize_gc_policy_counters();
651
652 virtual HeapWord* mem_allocate_work(size_t size,
653 bool is_tlab,
654 bool* gc_overhead_limit_was_exceeded);
655
656 // This method controls how a collector handles one or more
657 // of its generations being fully allocated.
658 virtual HeapWord* satisfy_failed_allocation(size_t size,
659 bool is_tlab);
660
661 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
662
663 bool about_to_start_mixed_phase() const;
664
665 // Record the start and end of an evacuation pause.
666 void record_collection_pause_start(double start_time_sec);
667 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned);
668
669 // Record the start and end of a full collection.
670 void record_full_collection_start();
671 void record_full_collection_end();
672
673 // Must currently be called while the world is stopped.
674 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
675
676 // Record start and end of remark.
677 void record_concurrent_mark_remark_start();
678 void record_concurrent_mark_remark_end();
679
680 // Record start, end, and completion of cleanup.
681 void record_concurrent_mark_cleanup_start();
682 void record_concurrent_mark_cleanup_end();
683 void record_concurrent_mark_cleanup_completed();
684
685 // Records the information about the heap size for reporting in
686 // print_detailed_heap_transition
687 void record_heap_size_info_at_start(bool full);
688
689 // Print heap sizing transition (with less and more detail).
690
691 void print_heap_transition(size_t bytes_before) const;
692 void print_heap_transition() const;
693 void print_detailed_heap_transition(bool full = false) const;
694
695 virtual void print_phases(double pause_time_sec);
696
697 void record_stop_world_start();
698 void record_concurrent_pause();
699
700 // Record how much space we copied during a GC. This is typically
701 // called when a GC alloc region is being retired.
702 void record_bytes_copied_during_gc(size_t bytes) {
703 _bytes_copied_during_gc += bytes;
704 }
705
706 // The amount of space we copied during a GC.
707 size_t bytes_copied_during_gc() const {
708 return _bytes_copied_during_gc;
709 }
710
711 size_t collection_set_bytes_used_before() const {
712 return _collection_set_bytes_used_before;
713 }
714
715 // Determine whether there are candidate regions so that the
716 // next GC should be mixed. The two action strings are used
717 // in the ergo output when the method returns true or false.
718 bool next_gc_should_be_mixed(const char* true_action_str,
719 const char* false_action_str) const;
720
721 // Choose a new collection set. Marks the chosen regions as being
722 // "in_collection_set", and links them together. The head and number of
723 // the collection set are available via access methods.
724 double finalize_young_cset_part(double target_pause_time_ms);
725 virtual void finalize_old_cset_part(double time_remaining_ms);
726
727 // The head of the list (via "next_in_collection_set()") representing the
728 // current collection set.
729 HeapRegion* collection_set() { return _collection_set; }
730
731 void clear_collection_set() { _collection_set = NULL; }
732
733 // Add old region "hr" to the CSet.
734 void add_old_region_to_cset(HeapRegion* hr);
735
736 // Incremental CSet Support
737
738 // The head of the incrementally built collection set.
739 HeapRegion* inc_cset_head() { return _inc_cset_head; }
740
741 // The tail of the incrementally built collection set.
742 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
743
744 // Initialize incremental collection set info.
745 void start_incremental_cset_building();
746
747 // Perform any final calculations on the incremental CSet fields
748 // before we can use them.
749 void finalize_incremental_cset_building();
750
751 void clear_incremental_cset() {
752 _inc_cset_head = NULL;
753 _inc_cset_tail = NULL;
754 }
755
756 // Stop adding regions to the incremental collection set
757 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
758
759 // Add information about hr to the aggregated information for the
760 // incrementally built collection set.
761 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
762
763 // Update information about hr in the aggregated information for
764 // the incrementally built collection set.
765 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
766
767 private:
768 // Update the incremental cset information when adding a region
769 // (should not be called directly).
770 void add_region_to_incremental_cset_common(HeapRegion* hr);
771
772 public:
773 // Add hr to the LHS of the incremental collection set.
774 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
775
776 // Add hr to the RHS of the incremental collection set.
777 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
778
779 #ifndef PRODUCT
780 void print_collection_set(HeapRegion* list_head, outputStream* st);
781 #endif // !PRODUCT
782
783 // This sets the initiate_conc_mark_if_possible() flag to start a
784 // new cycle, as long as we are not already in one. It's best if it
785 // is called during a safepoint when the test whether a cycle is in
786 // progress or not is stable.
787 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
788
789 // This is called at the very beginning of an evacuation pause (it
790 // has to be the first thing that the pause does). If
791 // initiate_conc_mark_if_possible() is true, and the concurrent
792 // marking thread has completed its work during the previous cycle,
793 // it will set during_initial_mark_pause() to so that the pause does
794 // the initial-mark work and start a marking cycle.
795 void decide_on_conc_mark_initiation();
796
797 // If an expansion would be appropriate, because recent GC overhead had
798 // exceeded the desired limit, return an amount to expand by.
799 virtual size_t expansion_amount() const;
800
801 // Print tracing information.
802 void print_tracing_info() const;
803
804 // Print stats on young survival ratio
805 void print_yg_surv_rate_info() const;
806
807 void finished_recalculating_age_indexes(bool is_survivors) {
808 if (is_survivors) {
809 _survivor_surv_rate_group->finished_recalculating_age_indexes();
810 } else {
811 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
812 }
813 // do that for any other surv rate groups
814 }
815
816 size_t young_list_target_length() const { return _young_list_target_length; }
817
818 bool is_young_list_full() const;
819
820 bool can_expand_young_list() const;
821
822 uint young_list_max_length() const {
823 return _young_list_max_length;
824 }
825
826 bool adaptive_young_list_length() const {
827 return _young_gen_sizer->adaptive_young_list_length();
828 }
829
830 private:
831 //
832 // Survivor regions policy.
833 //
834
835 // Current tenuring threshold, set to 0 if the collector reaches the
836 // maximum amount of survivors regions.
837 uint _tenuring_threshold;
838
839 // The limit on the number of regions allocated for survivors.
840 uint _max_survivor_regions;
841
842 // For reporting purposes.
843 // The value of _heap_bytes_before_gc is also used to calculate
844 // the cost of copying.
845
846 size_t _eden_used_bytes_before_gc; // Eden occupancy before GC
847 size_t _survivor_used_bytes_before_gc; // Survivor occupancy before GC
848 size_t _heap_used_bytes_before_gc; // Heap occupancy before GC
849 size_t _metaspace_used_bytes_before_gc; // Metaspace occupancy before GC
850
851 size_t _eden_capacity_bytes_before_gc; // Eden capacity before GC
852 size_t _heap_capacity_bytes_before_gc; // Heap capacity before GC
853
854 // The amount of survivor regions after a collection.
855 uint _recorded_survivor_regions;
856 // List of survivor regions.
857 HeapRegion* _recorded_survivor_head;
858 HeapRegion* _recorded_survivor_tail;
859
860 ageTable _survivors_age_table;
861
862 public:
863 uint tenuring_threshold() const { return _tenuring_threshold; }
864
865 static const uint REGIONS_UNLIMITED = (uint) -1;
866
867 uint max_regions(InCSetState dest) const {
868 switch (dest.value()) {
869 case InCSetState::Young:
870 return _max_survivor_regions;
871 case InCSetState::Old:
872 return REGIONS_UNLIMITED;
873 default:
874 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value());
875 break;
876 }
877 // keep some compilers happy
878 return 0;
879 }
880
881 void note_start_adding_survivor_regions() {
882 _survivor_surv_rate_group->start_adding_regions();
883 }
884
885 void note_stop_adding_survivor_regions() {
886 _survivor_surv_rate_group->stop_adding_regions();
887 }
888
889 void record_survivor_regions(uint regions,
890 HeapRegion* head,
891 HeapRegion* tail) {
892 _recorded_survivor_regions = regions;
893 _recorded_survivor_head = head;
894 _recorded_survivor_tail = tail;
895 }
896
897 uint recorded_survivor_regions() const {
898 return _recorded_survivor_regions;
899 }
900
901 void record_age_table(ageTable* age_table) {
902 _survivors_age_table.merge(age_table);
903 }
904
905 void update_max_gc_locker_expansion();
906
907 // Calculates survivor space parameters.
908 void update_survivors_policy();
909
910 virtual void post_heap_initialize();
911 };
912
913 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP