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
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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/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
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 const G1Predictions& predictor() const { 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 protected:
382 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
383 virtual double other_time_ms(double pause_time_ms) const;
384
385 double young_other_time_ms() const;
386 double non_young_other_time_ms() const;
387 double constant_other_time_ms(double pause_time_ms) const;
388
389 private:
390 // Statistics kept per GC stoppage, pause or full.
391 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
392
393 // Add a new GC of the given duration and end time to the record.
394 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
395
396 // The head of the list (via "next_in_collection_set()") representing the
397 // current collection set. Set from the incrementally built collection
398 // set at the start of the pause.
399 HeapRegion* _collection_set;
400
401 // The number of bytes in the collection set before the pause. Set from
402 // the incrementally built collection set at the start of an evacuation
403 // pause, and incremented in finalize_old_cset_part() when adding old regions
404 // (if any) to the collection set.
405 size_t _collection_set_bytes_used_before;
406
407 // The number of bytes copied during the GC.
408 size_t _bytes_copied_during_gc;
409
410 // The associated information that is maintained while the incremental
411 // collection set is being built with young regions. Used to populate
412 // the recorded info for the evacuation pause.
413
414 enum CSetBuildType {
415 Active, // We are actively building the collection set
416 Inactive // We are not actively building the collection set
417 };
418
419 CSetBuildType _inc_cset_build_state;
420
421 // The head of the incrementally built collection set.
422 HeapRegion* _inc_cset_head;
423
424 // The tail of the incrementally built collection set.
425 HeapRegion* _inc_cset_tail;
426
427 // The number of bytes in the incrementally built collection set.
428 // Used to set _collection_set_bytes_used_before at the start of
429 // an evacuation pause.
430 size_t _inc_cset_bytes_used_before;
431
432 // Used to record the highest end of heap region in collection set
433 HeapWord* _inc_cset_max_finger;
434
435 // The RSet lengths recorded for regions in the CSet. It is updated
436 // by the thread that adds a new region to the CSet. We assume that
437 // only one thread can be allocating a new CSet region (currently,
438 // it does so after taking the Heap_lock) hence no need to
439 // synchronize updates to this field.
440 size_t _inc_cset_recorded_rs_lengths;
441
442 // A concurrent refinement thread periodically samples the young
443 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
444 // the RSets grow. Instead of having to synchronize updates to that
445 // field we accumulate them in this field and add it to
446 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
447 ssize_t _inc_cset_recorded_rs_lengths_diffs;
448
449 // The predicted elapsed time it will take to collect the regions in
450 // the CSet. This is updated by the thread that adds a new region to
451 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
452 // MT-safety assumptions.
453 double _inc_cset_predicted_elapsed_time_ms;
454
455 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
456 double _inc_cset_predicted_elapsed_time_ms_diffs;
457
458 // Stash a pointer to the g1 heap.
459 G1CollectedHeap* _g1;
460
461 G1GCPhaseTimes* _phase_times;
462
463 // The ratio of gc time to elapsed time, computed over recent pauses.
464 double _recent_avg_pause_time_ratio;
465
466 double recent_avg_pause_time_ratio() const {
467 return _recent_avg_pause_time_ratio;
468 }
469
470 // This set of variables tracks the collector efficiency, in order to
471 // determine whether we should initiate a new marking.
472 double _cur_mark_stop_world_time_ms;
473 double _mark_remark_start_sec;
474 double _mark_cleanup_start_sec;
475
476 void update_young_list_max_and_target_length();
477 void update_young_list_max_and_target_length(size_t rs_lengths);
478
479 // Update the young list target length either by setting it to the
480 // desired fixed value or by calculating it using G1's pause
481 // prediction model. If no rs_lengths parameter is passed, predict
482 // the RS lengths using the prediction model, otherwise use the
483 // given rs_lengths as the prediction.
484 void update_young_list_target_length();
485 void update_young_list_target_length(size_t rs_lengths);
486
487 // Calculate and return the minimum desired young list target
488 // length. This is the minimum desired young list length according
489 // to the user's inputs.
490 uint calculate_young_list_desired_min_length(uint base_min_length) const;
491
492 // Calculate and return the maximum desired young list target
493 // length. This is the maximum desired young list length according
494 // to the user's inputs.
495 uint calculate_young_list_desired_max_length() const;
496
497 // Calculate and return the maximum young list target length that
498 // can fit into the pause time goal. The parameters are: rs_lengths
499 // represent the prediction of how large the young RSet lengths will
500 // be, base_min_length is the already existing number of regions in
501 // the young list, min_length and max_length are the desired min and
502 // max young list length according to the user's inputs.
503 uint calculate_young_list_target_length(size_t rs_lengths,
504 uint base_min_length,
505 uint desired_min_length,
506 uint desired_max_length) const;
507
508 uint bounded_young_list_target_length(size_t rs_lengths) const;
509
510 void update_rs_lengths_prediction();
511 void update_rs_lengths_prediction(size_t prediction);
512
513 // Calculate and return chunk size (in number of regions) for parallel
514 // concurrent mark cleanup.
515 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
516
517 // Check whether a given young length (young_length) fits into the
518 // given target pause time and whether the prediction for the amount
519 // of objects to be copied for the given length will fit into the
520 // given free space (expressed by base_free_regions). It is used by
521 // calculate_young_list_target_length().
522 bool predict_will_fit(uint young_length, double base_time_ms,
523 uint base_free_regions, double target_pause_time_ms) const;
524
525 // Calculate the minimum number of old regions we'll add to the CSet
526 // during a mixed GC.
527 uint calc_min_old_cset_length() const;
528
529 // Calculate the maximum number of old regions we'll add to the CSet
530 // during a mixed GC.
531 uint calc_max_old_cset_length() const;
532
533 // Returns the given amount of uncollected reclaimable space
534 // as a percentage of the current heap capacity.
535 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
536
537 // Sets up marking if proper conditions are met.
538 void maybe_start_marking();
539 public:
540
541 G1CollectorPolicy();
542
543 virtual G1CollectorPolicy* as_g1_policy() { return this; }
544
545 G1CollectorState* collector_state() const;
546
547 G1GCPhaseTimes* phase_times() const { return _phase_times; }
548
549 // Check the current value of the young list RSet lengths and
550 // compare it against the last prediction. If the current value is
551 // higher, recalculate the young list target length prediction.
552 void revise_young_list_target_length_if_necessary();
553
554 // This should be called after the heap is resized.
555 void record_new_heap_size(uint new_number_of_regions);
556
557 void init();
558
559 virtual void note_gc_start(uint num_active_workers);
560
561 // Create jstat counters for the policy.
562 virtual void initialize_gc_policy_counters();
563
564 virtual HeapWord* mem_allocate_work(size_t size,
565 bool is_tlab,
566 bool* gc_overhead_limit_was_exceeded);
567
568 // This method controls how a collector handles one or more
569 // of its generations being fully allocated.
570 virtual HeapWord* satisfy_failed_allocation(size_t size,
571 bool is_tlab);
572
573 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
574
575 bool about_to_start_mixed_phase() const;
576
577 // Record the start and end of an evacuation pause.
578 void record_collection_pause_start(double start_time_sec);
579 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned);
580
581 // Record the start and end of a full collection.
582 void record_full_collection_start();
583 void record_full_collection_end();
584
585 // Must currently be called while the world is stopped.
586 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
587
588 // Record start and end of remark.
589 void record_concurrent_mark_remark_start();
590 void record_concurrent_mark_remark_end();
591
592 // Record start, end, and completion of cleanup.
593 void record_concurrent_mark_cleanup_start();
594 void record_concurrent_mark_cleanup_end();
595 void record_concurrent_mark_cleanup_completed();
596
597 // Records the information about the heap size for reporting in
598 // print_detailed_heap_transition
599 void record_heap_size_info_at_start(bool full);
600
601 // Print heap sizing transition (with less and more detail).
602
603 void print_heap_transition(size_t bytes_before) const;
604 void print_heap_transition() const;
605 void print_detailed_heap_transition(bool full = false) const;
606
607 virtual void print_phases(double pause_time_sec);
608
609 void record_stop_world_start();
610 void record_concurrent_pause();
611
612 // Record how much space we copied during a GC. This is typically
613 // called when a GC alloc region is being retired.
614 void record_bytes_copied_during_gc(size_t bytes) {
615 _bytes_copied_during_gc += bytes;
616 }
617
618 // The amount of space we copied during a GC.
619 size_t bytes_copied_during_gc() const {
620 return _bytes_copied_during_gc;
621 }
622
623 size_t collection_set_bytes_used_before() const {
624 return _collection_set_bytes_used_before;
625 }
626
627 // Determine whether there are candidate regions so that the
628 // next GC should be mixed. The two action strings are used
629 // in the ergo output when the method returns true or false.
630 bool next_gc_should_be_mixed(const char* true_action_str,
631 const char* false_action_str) const;
632
633 // Choose a new collection set. Marks the chosen regions as being
634 // "in_collection_set", and links them together. The head and number of
635 // the collection set are available via access methods.
636 double finalize_young_cset_part(double target_pause_time_ms);
637 virtual void finalize_old_cset_part(double time_remaining_ms);
638
639 // The head of the list (via "next_in_collection_set()") representing the
640 // current collection set.
641 HeapRegion* collection_set() { return _collection_set; }
642
643 void clear_collection_set() { _collection_set = NULL; }
644
645 // Add old region "hr" to the CSet.
646 void add_old_region_to_cset(HeapRegion* hr);
647
648 // Incremental CSet Support
649
650 // The head of the incrementally built collection set.
651 HeapRegion* inc_cset_head() { return _inc_cset_head; }
652
653 // The tail of the incrementally built collection set.
654 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
655
656 // Initialize incremental collection set info.
657 void start_incremental_cset_building();
658
659 // Perform any final calculations on the incremental CSet fields
660 // before we can use them.
661 void finalize_incremental_cset_building();
662
663 void clear_incremental_cset() {
664 _inc_cset_head = NULL;
665 _inc_cset_tail = NULL;
666 }
667
668 // Stop adding regions to the incremental collection set
669 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
670
671 // Add information about hr to the aggregated information for the
672 // incrementally built collection set.
673 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
674
675 // Update information about hr in the aggregated information for
676 // the incrementally built collection set.
677 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
678
679 private:
680 // Update the incremental cset information when adding a region
681 // (should not be called directly).
682 void add_region_to_incremental_cset_common(HeapRegion* hr);
683
684 public:
685 // Add hr to the LHS of the incremental collection set.
686 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
687
688 // Add hr to the RHS of the incremental collection set.
689 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
690
691 #ifndef PRODUCT
692 void print_collection_set(HeapRegion* list_head, outputStream* st);
693 #endif // !PRODUCT
694
695 // This sets the initiate_conc_mark_if_possible() flag to start a
696 // new cycle, as long as we are not already in one. It's best if it
697 // is called during a safepoint when the test whether a cycle is in
698 // progress or not is stable.
699 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
700
701 // This is called at the very beginning of an evacuation pause (it
702 // has to be the first thing that the pause does). If
703 // initiate_conc_mark_if_possible() is true, and the concurrent
704 // marking thread has completed its work during the previous cycle,
705 // it will set during_initial_mark_pause() to so that the pause does
706 // the initial-mark work and start a marking cycle.
707 void decide_on_conc_mark_initiation();
708
709 // If an expansion would be appropriate, because recent GC overhead had
710 // exceeded the desired limit, return an amount to expand by.
711 virtual size_t expansion_amount() const;
712
713 // Print tracing information.
714 void print_tracing_info() const;
715
716 // Print stats on young survival ratio
717 void print_yg_surv_rate_info() const;
718
719 void finished_recalculating_age_indexes(bool is_survivors) {
720 if (is_survivors) {
721 _survivor_surv_rate_group->finished_recalculating_age_indexes();
722 } else {
723 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
724 }
725 // do that for any other surv rate groups
726 }
727
728 size_t young_list_target_length() const { return _young_list_target_length; }
729
730 bool is_young_list_full() const;
731
732 bool can_expand_young_list() const;
733
734 uint young_list_max_length() const {
735 return _young_list_max_length;
736 }
737
738 bool adaptive_young_list_length() const {
739 return _young_gen_sizer->adaptive_young_list_length();
740 }
741
742 private:
743 //
744 // Survivor regions policy.
745 //
746
747 // Current tenuring threshold, set to 0 if the collector reaches the
748 // maximum amount of survivors regions.
749 uint _tenuring_threshold;
750
751 // The limit on the number of regions allocated for survivors.
752 uint _max_survivor_regions;
753
754 // For reporting purposes.
755 // The value of _heap_bytes_before_gc is also used to calculate
756 // the cost of copying.
757
758 size_t _eden_used_bytes_before_gc; // Eden occupancy before GC
759 size_t _survivor_used_bytes_before_gc; // Survivor occupancy before GC
760 size_t _heap_used_bytes_before_gc; // Heap occupancy before GC
761 size_t _metaspace_used_bytes_before_gc; // Metaspace occupancy before GC
762
763 size_t _eden_capacity_bytes_before_gc; // Eden capacity before GC
764 size_t _heap_capacity_bytes_before_gc; // Heap capacity before GC
765
766 // The amount of survivor regions after a collection.
767 uint _recorded_survivor_regions;
768 // List of survivor regions.
769 HeapRegion* _recorded_survivor_head;
770 HeapRegion* _recorded_survivor_tail;
771
772 ageTable _survivors_age_table;
773
774 public:
775 uint tenuring_threshold() const { return _tenuring_threshold; }
776
777 static const uint REGIONS_UNLIMITED = (uint) -1;
778
779 uint max_regions(InCSetState dest) const {
780 switch (dest.value()) {
781 case InCSetState::Young:
782 return _max_survivor_regions;
783 case InCSetState::Old:
784 return REGIONS_UNLIMITED;
785 default:
786 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value());
787 break;
788 }
789 // keep some compilers happy
790 return 0;
791 }
792
793 void note_start_adding_survivor_regions() {
794 _survivor_surv_rate_group->start_adding_regions();
795 }
796
797 void note_stop_adding_survivor_regions() {
798 _survivor_surv_rate_group->stop_adding_regions();
799 }
800
801 void record_survivor_regions(uint regions,
802 HeapRegion* head,
803 HeapRegion* tail) {
804 _recorded_survivor_regions = regions;
805 _recorded_survivor_head = head;
806 _recorded_survivor_tail = tail;
807 }
808
809 uint recorded_survivor_regions() const {
810 return _recorded_survivor_regions;
811 }
812
813 void record_age_table(ageTable* age_table) {
814 _survivors_age_table.merge(age_table);
815 }
816
817 void update_max_gc_locker_expansion();
818
819 // Calculates survivor space parameters.
820 void update_survivors_policy();
821
822 virtual void post_heap_initialize();
823 };
824
825 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP