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
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,
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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/g1GCPhaseTimes.hpp"
31 #include "gc/g1/g1InCSetState.hpp"
32 #include "gc/g1/g1InitialMarkToMixedTimeTracker.hpp"
33 #include "gc/g1/g1MMUTracker.hpp"
34 #include "gc/g1/g1Predictions.hpp"
35 #include "gc/shared/collectorPolicy.hpp"
36 #include "utilities/pair.hpp"
37
38 // A G1CollectorPolicy makes policy decisions that determine the
39 // characteristics of the collector. Examples include:
40 // * choice of collection set.
41 // * when to collect.
42
43 class HeapRegion;
44 class CollectionSetChooser;
45 class G1IHOPControl;
46
47 // TraceYoungGenTime collects data on _both_ young and mixed evacuation pauses
48 // (the latter may contain non-young regions - i.e. regions that are
49 // technically in old) while TraceOldGenTime collects data about full GCs.
50 class TraceYoungGenTimeData : public CHeapObj<mtGC> {
51 private:
52 unsigned _young_pause_num;
53 unsigned _mixed_pause_num;
54
55 NumberSeq _all_stop_world_times_ms;
56 NumberSeq _all_yield_times_ms;
57
58 NumberSeq _total;
59 NumberSeq _other;
60 NumberSeq _root_region_scan_wait;
61 NumberSeq _parallel;
62 NumberSeq _ext_root_scan;
63 NumberSeq _satb_filtering;
64 NumberSeq _update_rs;
65 NumberSeq _scan_rs;
66 NumberSeq _obj_copy;
67 NumberSeq _termination;
68 NumberSeq _parallel_other;
69 NumberSeq _clear_ct;
70
71 void print_summary(const char* str, const NumberSeq* seq) const;
72 void print_summary_sd(const char* str, const NumberSeq* seq) const;
73
74 public:
75 TraceYoungGenTimeData() : _young_pause_num(0), _mixed_pause_num(0) {};
76 void record_start_collection(double time_to_stop_the_world_ms);
77 void record_yield_time(double yield_time_ms);
78 void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times);
79 void increment_young_collection_count();
80 void increment_mixed_collection_count();
81 void print() const;
82 };
83
84 class TraceOldGenTimeData : public CHeapObj<mtGC> {
85 private:
86 NumberSeq _all_full_gc_times;
87
88 public:
89 void record_full_collection(double full_gc_time_ms);
90 void print() const;
91 };
92
93 // There are three command line options related to the young gen size:
94 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
95 // just a short form for NewSize==MaxNewSize). G1 will use its internal
96 // heuristics to calculate the actual young gen size, so these options
97 // basically only limit the range within which G1 can pick a young gen
98 // size. Also, these are general options taking byte sizes. G1 will
99 // internally work with a number of regions instead. So, some rounding
100 // will occur.
101 //
102 // If nothing related to the the young gen size is set on the command
103 // line we should allow the young gen to be between G1NewSizePercent
104 // and G1MaxNewSizePercent of the heap size. This means that every time
105 // the heap size changes, the limits for the young gen size will be
106 // recalculated.
107 //
108 // If only -XX:NewSize is set we should use the specified value as the
109 // minimum size for young gen. Still using G1MaxNewSizePercent of the
110 // heap as maximum.
111 //
112 // If only -XX:MaxNewSize is set we should use the specified value as the
113 // maximum size for young gen. Still using G1NewSizePercent of the heap
114 // as minimum.
115 //
116 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
117 // No updates when the heap size changes. There is a special case when
118 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
119 // different heuristic for calculating the collection set when we do mixed
120 // collection.
121 //
122 // If only -XX:NewRatio is set we should use the specified ratio of the heap
123 // as both min and max. This will be interpreted as "fixed" just like the
124 // NewSize==MaxNewSize case above. But we will update the min and max
125 // every time the heap size changes.
126 //
127 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
128 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
129 class G1YoungGenSizer : public CHeapObj<mtGC> {
130 private:
131 enum SizerKind {
132 SizerDefaults,
133 SizerNewSizeOnly,
134 SizerMaxNewSizeOnly,
135 SizerMaxAndNewSize,
136 SizerNewRatio
137 };
138 SizerKind _sizer_kind;
139 uint _min_desired_young_length;
140 uint _max_desired_young_length;
141 bool _adaptive_size;
142 uint calculate_default_min_length(uint new_number_of_heap_regions);
143 uint calculate_default_max_length(uint new_number_of_heap_regions);
144
145 // Update the given values for minimum and maximum young gen length in regions
146 // given the number of heap regions depending on the kind of sizing algorithm.
147 void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length);
148
149 public:
150 G1YoungGenSizer();
151 // Calculate the maximum length of the young gen given the number of regions
152 // depending on the sizing algorithm.
153 uint max_young_length(uint number_of_heap_regions);
154
155 void heap_size_changed(uint new_number_of_heap_regions);
156 uint min_desired_young_length() {
157 return _min_desired_young_length;
158 }
159 uint max_desired_young_length() {
160 return _max_desired_young_length;
161 }
162 bool adaptive_young_list_length() const {
163 return _adaptive_size;
164 }
165 };
166
167 class G1CollectorPolicy: public CollectorPolicy {
168 private:
169 G1IHOPControl* _ihop_control;
170
171 G1IHOPControl* create_ihop_control() const;
172 // Update the IHOP control with necessary statistics.
173 void update_ihop_prediction(double mutator_time_s,
174 size_t mutator_alloc_bytes,
175 size_t young_gen_size);
176 void report_ihop_statistics();
177
178 G1Predictions _predictor;
179
180 double get_new_prediction(TruncatedSeq const* seq) const;
181
182 // either equal to the number of parallel threads, if ParallelGCThreads
183 // has been set, or 1 otherwise
184 int _parallel_gc_threads;
185
186 // The number of GC threads currently active.
187 uintx _no_of_gc_threads;
188
189 G1MMUTracker* _mmu_tracker;
190
191 void initialize_alignments();
192 void initialize_flags();
193
194 CollectionSetChooser* _cset_chooser;
195
196 double _full_collection_start_sec;
197
198 // These exclude marking times.
199 TruncatedSeq* _recent_gc_times_ms;
200
201 TruncatedSeq* _concurrent_mark_remark_times_ms;
202 TruncatedSeq* _concurrent_mark_cleanup_times_ms;
203
204 TraceYoungGenTimeData _trace_young_gen_time_data;
205 TraceOldGenTimeData _trace_old_gen_time_data;
206
207 double _stop_world_start;
208
209 uint _young_list_target_length;
210 uint _young_list_fixed_length;
211
212 // The max number of regions we can extend the eden by while the GC
213 // locker is active. This should be >= _young_list_target_length;
214 uint _young_list_max_length;
215
216 SurvRateGroup* _short_lived_surv_rate_group;
217 SurvRateGroup* _survivor_surv_rate_group;
218 // add here any more surv rate groups
219
220 double _gc_overhead_perc;
221
222 double _reserve_factor;
223 uint _reserve_regions;
224
225 enum PredictionConstants {
226 TruncatedSeqLength = 10,
227 NumPrevPausesForHeuristics = 10
228 };
229
230 TruncatedSeq* _alloc_rate_ms_seq;
231 double _prev_collection_pause_end_ms;
232
233 TruncatedSeq* _rs_length_diff_seq;
234 TruncatedSeq* _cost_per_card_ms_seq;
235 TruncatedSeq* _cost_scan_hcc_seq;
236 TruncatedSeq* _young_cards_per_entry_ratio_seq;
237 TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
238 TruncatedSeq* _cost_per_entry_ms_seq;
239 TruncatedSeq* _mixed_cost_per_entry_ms_seq;
240 TruncatedSeq* _cost_per_byte_ms_seq;
241 TruncatedSeq* _constant_other_time_ms_seq;
242 TruncatedSeq* _young_other_cost_per_region_ms_seq;
243 TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
244
245 TruncatedSeq* _pending_cards_seq;
246 TruncatedSeq* _rs_lengths_seq;
247
248 TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
249
250 G1YoungGenSizer* _young_gen_sizer;
251
252 uint _eden_cset_region_length;
253 uint _survivor_cset_region_length;
254 uint _old_cset_region_length;
255
256 void init_cset_region_lengths(uint eden_cset_region_length,
257 uint survivor_cset_region_length);
258
259 uint eden_cset_region_length() const { return _eden_cset_region_length; }
260 uint survivor_cset_region_length() const { return _survivor_cset_region_length; }
261 uint old_cset_region_length() const { return _old_cset_region_length; }
262
263 uint _free_regions_at_end_of_collection;
264
265 size_t _recorded_rs_lengths;
266 size_t _max_rs_lengths;
267
268 size_t _rs_lengths_prediction;
269
270 #ifndef PRODUCT
271 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
272 #endif // PRODUCT
273
274 void adjust_concurrent_refinement(double update_rs_time,
275 double update_rs_processed_buffers,
276 double goal_ms);
277
278 uintx no_of_gc_threads() { return _no_of_gc_threads; }
279 void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
280
281 double _pause_time_target_ms;
282
283 size_t _pending_cards;
284
285 // The amount of allocated bytes in old gen during the last mutator and the following
286 // young GC phase.
287 size_t _bytes_allocated_in_old_since_last_gc;
288
289 G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
290 public:
291 const G1Predictions& predictor() const { return _predictor; }
292
293 // Add the given number of bytes to the total number of allocated bytes in the old gen.
294 void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
295
296 // Accessors
297
298 void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
299 hr->set_eden();
300 hr->install_surv_rate_group(_short_lived_surv_rate_group);
301 hr->set_young_index_in_cset(young_index_in_cset);
302 }
303
304 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
305 assert(hr->is_survivor(), "pre-condition");
306 hr->install_surv_rate_group(_survivor_surv_rate_group);
307 hr->set_young_index_in_cset(young_index_in_cset);
308 }
309
310 #ifndef PRODUCT
311 bool verify_young_ages();
312 #endif // PRODUCT
313
314 void record_max_rs_lengths(size_t rs_lengths) {
315 _max_rs_lengths = rs_lengths;
316 }
317
318 size_t predict_rs_length_diff() const;
319
320 double predict_alloc_rate_ms() const;
321
322 double predict_cost_per_card_ms() const;
323
324 double predict_scan_hcc_ms() const;
325
326 double predict_rs_update_time_ms(size_t pending_cards) const;
327
328 double predict_young_cards_per_entry_ratio() const;
329
330 double predict_mixed_cards_per_entry_ratio() const;
331
332 size_t predict_young_card_num(size_t rs_length) const;
333
334 size_t predict_non_young_card_num(size_t rs_length) const;
335
336 double predict_rs_scan_time_ms(size_t card_num) const;
337
338 double predict_mixed_rs_scan_time_ms(size_t card_num) const;
339
340 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
341
342 double predict_object_copy_time_ms(size_t bytes_to_copy) const;
343
344 double predict_constant_other_time_ms() const;
345
346 double predict_young_other_time_ms(size_t young_num) const;
347
348 double predict_non_young_other_time_ms(size_t non_young_num) const;
349
350 double predict_base_elapsed_time_ms(size_t pending_cards) const;
351 double predict_base_elapsed_time_ms(size_t pending_cards,
352 size_t scanned_cards) const;
353 size_t predict_bytes_to_copy(HeapRegion* hr) const;
354 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
355
356 void set_recorded_rs_lengths(size_t rs_lengths);
357
358 uint cset_region_length() const { return young_cset_region_length() +
359 old_cset_region_length(); }
360 uint young_cset_region_length() const { return eden_cset_region_length() +
361 survivor_cset_region_length(); }
362
363 double predict_survivor_regions_evac_time() const;
364
365 bool should_update_surv_rate_group_predictors() {
366 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
367 }
368
369 void cset_regions_freed() {
370 bool update = should_update_surv_rate_group_predictors();
371
372 _short_lived_surv_rate_group->all_surviving_words_recorded(update);
373 _survivor_surv_rate_group->all_surviving_words_recorded(update);
374 }
375
376 G1MMUTracker* mmu_tracker() {
377 return _mmu_tracker;
378 }
379
380 const G1MMUTracker* mmu_tracker() const {
381 return _mmu_tracker;
382 }
383
384 double max_pause_time_ms() const {
385 return _mmu_tracker->max_gc_time() * 1000.0;
386 }
387
388 double predict_remark_time_ms() const;
389
390 double predict_cleanup_time_ms() const;
391
392 // Returns an estimate of the survival rate of the region at yg-age
393 // "yg_age".
394 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
395
396 double predict_yg_surv_rate(int age) const;
397
398 double accum_yg_surv_rate_pred(int age) const;
399
400 protected:
401 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
402 virtual double other_time_ms(double pause_time_ms) const;
403
404 double young_other_time_ms() const;
405 double non_young_other_time_ms() const;
406 double constant_other_time_ms(double pause_time_ms) const;
407
408 CollectionSetChooser* cset_chooser() const {
409 return _cset_chooser;
410 }
411
412 private:
413 // Statistics kept per GC stoppage, pause or full.
414 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
415
416 // Add a new GC of the given duration and end time to the record.
417 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
418
419 // The head of the list (via "next_in_collection_set()") representing the
420 // current collection set. Set from the incrementally built collection
421 // set at the start of the pause.
422 HeapRegion* _collection_set;
423
424 // The number of bytes in the collection set before the pause. Set from
425 // the incrementally built collection set at the start of an evacuation
426 // pause, and incremented in finalize_old_cset_part() when adding old regions
427 // (if any) to the collection set.
428 size_t _collection_set_bytes_used_before;
429
430 // The number of bytes copied during the GC.
431 size_t _bytes_copied_during_gc;
432
433 // The associated information that is maintained while the incremental
434 // collection set is being built with young regions. Used to populate
435 // the recorded info for the evacuation pause.
436
437 enum CSetBuildType {
438 Active, // We are actively building the collection set
439 Inactive // We are not actively building the collection set
440 };
441
442 CSetBuildType _inc_cset_build_state;
443
444 // The head of the incrementally built collection set.
445 HeapRegion* _inc_cset_head;
446
447 // The tail of the incrementally built collection set.
448 HeapRegion* _inc_cset_tail;
449
450 // The number of bytes in the incrementally built collection set.
451 // Used to set _collection_set_bytes_used_before at the start of
452 // an evacuation pause.
453 size_t _inc_cset_bytes_used_before;
454
455 // Used to record the highest end of heap region in collection set
456 HeapWord* _inc_cset_max_finger;
457
458 // The RSet lengths recorded for regions in the CSet. It is updated
459 // by the thread that adds a new region to the CSet. We assume that
460 // only one thread can be allocating a new CSet region (currently,
461 // it does so after taking the Heap_lock) hence no need to
462 // synchronize updates to this field.
463 size_t _inc_cset_recorded_rs_lengths;
464
465 // A concurrent refinement thread periodically samples the young
466 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
467 // the RSets grow. Instead of having to synchronize updates to that
468 // field we accumulate them in this field and add it to
469 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
470 ssize_t _inc_cset_recorded_rs_lengths_diffs;
471
472 // The predicted elapsed time it will take to collect the regions in
473 // the CSet. This is updated by the thread that adds a new region to
474 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
475 // MT-safety assumptions.
476 double _inc_cset_predicted_elapsed_time_ms;
477
478 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
479 double _inc_cset_predicted_elapsed_time_ms_diffs;
480
481 // Stash a pointer to the g1 heap.
482 G1CollectedHeap* _g1;
483
484 G1GCPhaseTimes* _phase_times;
485
486 // The ratio of gc time to elapsed time, computed over recent pauses.
487 double _recent_avg_pause_time_ratio;
488
489 double recent_avg_pause_time_ratio() const {
490 return _recent_avg_pause_time_ratio;
491 }
492
493 // This set of variables tracks the collector efficiency, in order to
494 // determine whether we should initiate a new marking.
495 double _cur_mark_stop_world_time_ms;
496 double _mark_remark_start_sec;
497 double _mark_cleanup_start_sec;
498
499 // Updates the internal young list maximum and target lengths. Returns the
500 // unbounded young list target length.
501 uint update_young_list_max_and_target_length();
502 uint update_young_list_max_and_target_length(size_t rs_lengths);
503
504 // Update the young list target length either by setting it to the
505 // desired fixed value or by calculating it using G1's pause
506 // prediction model. If no rs_lengths parameter is passed, predict
507 // the RS lengths using the prediction model, otherwise use the
508 // given rs_lengths as the prediction.
509 // Returns the unbounded young list target length.
510 uint update_young_list_target_length(size_t rs_lengths);
511
512 // Calculate and return the minimum desired young list target
513 // length. This is the minimum desired young list length according
514 // to the user's inputs.
515 uint calculate_young_list_desired_min_length(uint base_min_length) const;
516
517 // Calculate and return the maximum desired young list target
518 // length. This is the maximum desired young list length according
519 // to the user's inputs.
520 uint calculate_young_list_desired_max_length() const;
521
522 // Calculate and return the maximum young list target length that
523 // can fit into the pause time goal. The parameters are: rs_lengths
524 // represent the prediction of how large the young RSet lengths will
525 // be, base_min_length is the already existing number of regions in
526 // the young list, min_length and max_length are the desired min and
527 // max young list length according to the user's inputs.
528 uint calculate_young_list_target_length(size_t rs_lengths,
529 uint base_min_length,
530 uint desired_min_length,
531 uint desired_max_length) const;
532
533 // Result of the bounded_young_list_target_length() method, containing both the
534 // bounded as well as the unbounded young list target lengths in this order.
535 typedef Pair<uint, uint, StackObj> YoungTargetLengths;
536 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
537
538 void update_rs_lengths_prediction();
539 void update_rs_lengths_prediction(size_t prediction);
540
541 // Calculate and return chunk size (in number of regions) for parallel
542 // concurrent mark cleanup.
543 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
544
545 // Check whether a given young length (young_length) fits into the
546 // given target pause time and whether the prediction for the amount
547 // of objects to be copied for the given length will fit into the
548 // given free space (expressed by base_free_regions). It is used by
549 // calculate_young_list_target_length().
550 bool predict_will_fit(uint young_length, double base_time_ms,
551 uint base_free_regions, double target_pause_time_ms) const;
552
553 // Calculate the minimum number of old regions we'll add to the CSet
554 // during a mixed GC.
555 uint calc_min_old_cset_length() const;
556
557 // Calculate the maximum number of old regions we'll add to the CSet
558 // during a mixed GC.
559 uint calc_max_old_cset_length() const;
560
561 // Returns the given amount of uncollected reclaimable space
562 // as a percentage of the current heap capacity.
563 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
564
565 // Sets up marking if proper conditions are met.
566 void maybe_start_marking();
567
568 // The kind of STW pause.
569 enum PauseKind {
570 FullGC,
571 YoungOnlyGC,
572 MixedGC,
573 LastYoungGC,
574 InitialMarkGC,
575 Cleanup,
576 Remark
577 };
578
579 // Calculate PauseKind from internal state.
580 PauseKind young_gc_pause_kind() const;
581 // Record the given STW pause with the given start and end times (in s).
582 void record_pause(PauseKind kind, double start, double end);
583 // Indicate that we aborted marking before doing any mixed GCs.
584 void abort_time_to_mixed_tracking();
585 public:
586
587 G1CollectorPolicy();
588
589 virtual ~G1CollectorPolicy();
590
591 virtual G1CollectorPolicy* as_g1_policy() { return this; }
592
593 G1CollectorState* collector_state() const;
594
595 G1GCPhaseTimes* phase_times() const { return _phase_times; }
596
597 // Check the current value of the young list RSet lengths and
598 // compare it against the last prediction. If the current value is
599 // higher, recalculate the young list target length prediction.
600 void revise_young_list_target_length_if_necessary();
601
602 // This should be called after the heap is resized.
603 void record_new_heap_size(uint new_number_of_regions);
604
605 void init();
606
607 virtual void note_gc_start(uint num_active_workers);
608
609 // Create jstat counters for the policy.
610 virtual void initialize_gc_policy_counters();
611
612 virtual HeapWord* mem_allocate_work(size_t size,
613 bool is_tlab,
614 bool* gc_overhead_limit_was_exceeded);
615
616 // This method controls how a collector handles one or more
617 // of its generations being fully allocated.
618 virtual HeapWord* satisfy_failed_allocation(size_t size,
619 bool is_tlab);
620
621 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
622
623 bool about_to_start_mixed_phase() const;
624
625 // Record the start and end of an evacuation pause.
626 void record_collection_pause_start(double start_time_sec);
627 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned);
628
629 // Record the start and end of a full collection.
630 void record_full_collection_start();
631 void record_full_collection_end();
632
633 // Must currently be called while the world is stopped.
634 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
635
636 // Record start and end of remark.
637 void record_concurrent_mark_remark_start();
638 void record_concurrent_mark_remark_end();
639
640 // Record start, end, and completion of cleanup.
641 void record_concurrent_mark_cleanup_start();
642 void record_concurrent_mark_cleanup_end();
643 void record_concurrent_mark_cleanup_completed();
644
645 // Records the information about the heap size for reporting in
646 // print_detailed_heap_transition
647 void record_heap_size_info_at_start(bool full);
648
649 // Print heap sizing transition (with less and more detail).
650
651 void print_heap_transition(size_t bytes_before) const;
652 void print_heap_transition() const;
653 void print_detailed_heap_transition(bool full = false) const;
654
655 virtual void print_phases(double pause_time_sec);
656
657 void record_stop_world_start();
658 void record_concurrent_pause();
659
660 // Record how much space we copied during a GC. This is typically
661 // called when a GC alloc region is being retired.
662 void record_bytes_copied_during_gc(size_t bytes) {
663 _bytes_copied_during_gc += bytes;
664 }
665
666 // The amount of space we copied during a GC.
667 size_t bytes_copied_during_gc() const {
668 return _bytes_copied_during_gc;
669 }
670
671 size_t collection_set_bytes_used_before() const {
672 return _collection_set_bytes_used_before;
673 }
674
675 // Determine whether there are candidate regions so that the
676 // next GC should be mixed. The two action strings are used
677 // in the ergo output when the method returns true or false.
678 bool next_gc_should_be_mixed(const char* true_action_str,
679 const char* false_action_str) const;
680
681 // Choose a new collection set. Marks the chosen regions as being
682 // "in_collection_set", and links them together. The head and number of
683 // the collection set are available via access methods.
684 double finalize_young_cset_part(double target_pause_time_ms);
685 virtual void finalize_old_cset_part(double time_remaining_ms);
686
687 // The head of the list (via "next_in_collection_set()") representing the
688 // current collection set.
689 HeapRegion* collection_set() { return _collection_set; }
690
691 void clear_collection_set() { _collection_set = NULL; }
692
693 // Add old region "hr" to the CSet.
694 void add_old_region_to_cset(HeapRegion* hr);
695
696 // Incremental CSet Support
697
698 // The head of the incrementally built collection set.
699 HeapRegion* inc_cset_head() { return _inc_cset_head; }
700
701 // The tail of the incrementally built collection set.
702 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
703
704 // Initialize incremental collection set info.
705 void start_incremental_cset_building();
706
707 // Perform any final calculations on the incremental CSet fields
708 // before we can use them.
709 void finalize_incremental_cset_building();
710
711 void clear_incremental_cset() {
712 _inc_cset_head = NULL;
713 _inc_cset_tail = NULL;
714 }
715
716 // Stop adding regions to the incremental collection set
717 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
718
719 // Add information about hr to the aggregated information for the
720 // incrementally built collection set.
721 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
722
723 // Update information about hr in the aggregated information for
724 // the incrementally built collection set.
725 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
726
727 private:
728 // Update the incremental cset information when adding a region
729 // (should not be called directly).
730 void add_region_to_incremental_cset_common(HeapRegion* hr);
731
732 // Set the state to start a concurrent marking cycle and clear
733 // _initiate_conc_mark_if_possible because it has now been
734 // acted on.
735 void initiate_conc_mark();
736
737 public:
738 // Add hr to the LHS of the incremental collection set.
739 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
740
741 // Add hr to the RHS of the incremental collection set.
742 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
743
744 #ifndef PRODUCT
745 void print_collection_set(HeapRegion* list_head, outputStream* st);
746 #endif // !PRODUCT
747
748 // This sets the initiate_conc_mark_if_possible() flag to start a
749 // new cycle, as long as we are not already in one. It's best if it
750 // is called during a safepoint when the test whether a cycle is in
751 // progress or not is stable.
752 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
753
754 // This is called at the very beginning of an evacuation pause (it
755 // has to be the first thing that the pause does). If
756 // initiate_conc_mark_if_possible() is true, and the concurrent
757 // marking thread has completed its work during the previous cycle,
758 // it will set during_initial_mark_pause() to so that the pause does
759 // the initial-mark work and start a marking cycle.
760 void decide_on_conc_mark_initiation();
761
762 // If an expansion would be appropriate, because recent GC overhead had
763 // exceeded the desired limit, return an amount to expand by.
764 virtual size_t expansion_amount() const;
765
766 // Print tracing information.
767 void print_tracing_info() const;
768
769 // Print stats on young survival ratio
770 void print_yg_surv_rate_info() const;
771
772 void finished_recalculating_age_indexes(bool is_survivors) {
773 if (is_survivors) {
774 _survivor_surv_rate_group->finished_recalculating_age_indexes();
775 } else {
776 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
777 }
778 // do that for any other surv rate groups
779 }
780
781 size_t young_list_target_length() const { return _young_list_target_length; }
782
783 bool is_young_list_full() const;
784
785 bool can_expand_young_list() const;
786
787 uint young_list_max_length() const {
788 return _young_list_max_length;
789 }
790
791 bool adaptive_young_list_length() const {
792 return _young_gen_sizer->adaptive_young_list_length();
793 }
794
795 virtual bool should_process_references() const {
796 return true;
797 }
798
799 private:
800 //
801 // Survivor regions policy.
802 //
803
804 // Current tenuring threshold, set to 0 if the collector reaches the
805 // maximum amount of survivors regions.
806 uint _tenuring_threshold;
807
808 // The limit on the number of regions allocated for survivors.
809 uint _max_survivor_regions;
810
811 // For reporting purposes.
812 // The value of _heap_bytes_before_gc is also used to calculate
813 // the cost of copying.
814
815 size_t _eden_used_bytes_before_gc; // Eden occupancy before GC
816 size_t _survivor_used_bytes_before_gc; // Survivor occupancy before GC
817 size_t _heap_used_bytes_before_gc; // Heap occupancy before GC
818 size_t _metaspace_used_bytes_before_gc; // Metaspace occupancy before GC
819
820 size_t _eden_capacity_bytes_before_gc; // Eden capacity before GC
821 size_t _heap_capacity_bytes_before_gc; // Heap capacity before GC
822
823 // The amount of survivor regions after a collection.
824 uint _recorded_survivor_regions;
825 // List of survivor regions.
826 HeapRegion* _recorded_survivor_head;
827 HeapRegion* _recorded_survivor_tail;
828
829 ageTable _survivors_age_table;
830
831 public:
832 uint tenuring_threshold() const { return _tenuring_threshold; }
833
834 static const uint REGIONS_UNLIMITED = (uint) -1;
835
836 uint max_regions(InCSetState dest) const {
837 switch (dest.value()) {
838 case InCSetState::Young:
839 return _max_survivor_regions;
840 case InCSetState::Old:
841 return REGIONS_UNLIMITED;
842 default:
843 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value());
844 break;
845 }
846 // keep some compilers happy
847 return 0;
848 }
849
850 void note_start_adding_survivor_regions() {
851 _survivor_surv_rate_group->start_adding_regions();
852 }
853
854 void note_stop_adding_survivor_regions() {
855 _survivor_surv_rate_group->stop_adding_regions();
856 }
857
858 void record_survivor_regions(uint regions,
859 HeapRegion* head,
860 HeapRegion* tail) {
861 _recorded_survivor_regions = regions;
862 _recorded_survivor_head = head;
863 _recorded_survivor_tail = tail;
864 }
865
866 uint recorded_survivor_regions() const {
867 return _recorded_survivor_regions;
868 }
869
870 void record_age_table(ageTable* age_table) {
871 _survivors_age_table.merge(age_table);
872 }
873
874 void update_max_gc_locker_expansion();
875
876 // Calculates survivor space parameters.
877 void update_survivors_policy();
878
879 virtual void post_heap_initialize();
880 };
881
882 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP