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,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_G1_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
163 bool adaptive_young_list_length() const {
164 return _adaptive_size;
165 }
166 };
167
168 class G1CollectorPolicy: public CollectorPolicy {
169 private:
170 G1IHOPControl* _ihop_control;
171
172 G1IHOPControl* create_ihop_control() const;
173 // Update the IHOP control with necessary statistics.
174 void update_ihop_prediction(double mutator_time_s,
175 size_t mutator_alloc_bytes,
176 size_t young_gen_size);
177 void report_ihop_statistics();
178
179 G1Predictions _predictor;
180
181 double get_new_prediction(TruncatedSeq const* seq) const;
182 size_t get_new_size_prediction(TruncatedSeq const* seq) const;
183
184 // either equal to the number of parallel threads, if ParallelGCThreads
185 // has been set, or 1 otherwise
186 int _parallel_gc_threads;
187
188 // The number of GC threads currently active.
189 uintx _no_of_gc_threads;
190
191 G1MMUTracker* _mmu_tracker;
192
193 void initialize_alignments();
194 void initialize_flags();
195
196 CollectionSetChooser* _cset_chooser;
197
198 double _full_collection_start_sec;
199
200 // These exclude marking times.
201 TruncatedSeq* _recent_gc_times_ms;
202
203 TruncatedSeq* _concurrent_mark_remark_times_ms;
204 TruncatedSeq* _concurrent_mark_cleanup_times_ms;
205
206 // Ratio check data for determining if heap growth is necessary.
207 uint _ratio_over_threshold_count;
208 double _ratio_over_threshold_sum;
209 uint _pauses_since_start;
210
211 TraceYoungGenTimeData _trace_young_gen_time_data;
212 TraceOldGenTimeData _trace_old_gen_time_data;
213
214 double _stop_world_start;
215
216 uint _young_list_target_length;
217 uint _young_list_fixed_length;
218
219 // The max number of regions we can extend the eden by while the GC
220 // locker is active. This should be >= _young_list_target_length;
221 uint _young_list_max_length;
222
223 SurvRateGroup* _short_lived_surv_rate_group;
224 SurvRateGroup* _survivor_surv_rate_group;
225 // add here any more surv rate groups
226
227 double _gc_overhead_perc;
228
229 double _reserve_factor;
230 uint _reserve_regions;
231
232 enum PredictionConstants {
233 TruncatedSeqLength = 10,
234 NumPrevPausesForHeuristics = 10,
235 // MinOverThresholdForGrowth must be less than NumPrevPausesForHeuristics,
236 // representing the minimum number of pause time ratios that exceed
237 // GCTimeRatio before a heap expansion will be triggered.
238 MinOverThresholdForGrowth = 4
239 };
240
241 TruncatedSeq* _alloc_rate_ms_seq;
242 double _prev_collection_pause_end_ms;
243
244 TruncatedSeq* _rs_length_diff_seq;
245 TruncatedSeq* _cost_per_card_ms_seq;
246 TruncatedSeq* _cost_scan_hcc_seq;
247 TruncatedSeq* _young_cards_per_entry_ratio_seq;
248 TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
249 TruncatedSeq* _cost_per_entry_ms_seq;
250 TruncatedSeq* _mixed_cost_per_entry_ms_seq;
251 TruncatedSeq* _cost_per_byte_ms_seq;
252 TruncatedSeq* _constant_other_time_ms_seq;
253 TruncatedSeq* _young_other_cost_per_region_ms_seq;
254 TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
255
256 TruncatedSeq* _pending_cards_seq;
257 TruncatedSeq* _rs_lengths_seq;
258
259 TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
260
261 G1YoungGenSizer* _young_gen_sizer;
262
263 uint _eden_cset_region_length;
264 uint _survivor_cset_region_length;
265 uint _old_cset_region_length;
266
267 void init_cset_region_lengths(uint eden_cset_region_length,
268 uint survivor_cset_region_length);
269
270 uint eden_cset_region_length() const { return _eden_cset_region_length; }
271 uint survivor_cset_region_length() const { return _survivor_cset_region_length; }
272 uint old_cset_region_length() const { return _old_cset_region_length; }
273
274 uint _free_regions_at_end_of_collection;
275
276 size_t _recorded_rs_lengths;
277 size_t _max_rs_lengths;
278
279 size_t _rs_lengths_prediction;
280
281 #ifndef PRODUCT
282 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
283 #endif // PRODUCT
284
285 void adjust_concurrent_refinement(double update_rs_time,
286 double update_rs_processed_buffers,
287 double goal_ms);
288
289 uintx no_of_gc_threads() { return _no_of_gc_threads; }
290 void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
291
292 double _pause_time_target_ms;
293
294 size_t _pending_cards;
295
296 // The amount of allocated bytes in old gen during the last mutator and the following
297 // young GC phase.
298 size_t _bytes_allocated_in_old_since_last_gc;
299
300 G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
301 public:
302 const G1Predictions& predictor() const { return _predictor; }
303
304 // Add the given number of bytes to the total number of allocated bytes in the old gen.
305 void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
306
307 // Accessors
308
309 void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
310 hr->set_eden();
311 hr->install_surv_rate_group(_short_lived_surv_rate_group);
312 hr->set_young_index_in_cset(young_index_in_cset);
313 }
314
315 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
316 assert(hr->is_survivor(), "pre-condition");
317 hr->install_surv_rate_group(_survivor_surv_rate_group);
318 hr->set_young_index_in_cset(young_index_in_cset);
319 }
320
321 #ifndef PRODUCT
322 bool verify_young_ages();
323 #endif // PRODUCT
324
325 void record_max_rs_lengths(size_t rs_lengths) {
326 _max_rs_lengths = rs_lengths;
327 }
328
329 size_t predict_rs_length_diff() const;
330
331 double predict_alloc_rate_ms() const;
332
333 double predict_cost_per_card_ms() const;
334
335 double predict_scan_hcc_ms() const;
336
337 double predict_rs_update_time_ms(size_t pending_cards) const;
338
339 double predict_young_cards_per_entry_ratio() const;
340
341 double predict_mixed_cards_per_entry_ratio() const;
342
343 size_t predict_young_card_num(size_t rs_length) const;
344
345 size_t predict_non_young_card_num(size_t rs_length) const;
346
347 double predict_rs_scan_time_ms(size_t card_num) const;
348
349 double predict_mixed_rs_scan_time_ms(size_t card_num) const;
350
351 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
352
353 double predict_object_copy_time_ms(size_t bytes_to_copy) const;
354
355 double predict_constant_other_time_ms() const;
356
357 double predict_young_other_time_ms(size_t young_num) const;
358
359 double predict_non_young_other_time_ms(size_t non_young_num) const;
360
361 double predict_base_elapsed_time_ms(size_t pending_cards) const;
362 double predict_base_elapsed_time_ms(size_t pending_cards,
363 size_t scanned_cards) const;
364 size_t predict_bytes_to_copy(HeapRegion* hr) const;
365 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
366
367 void set_recorded_rs_lengths(size_t rs_lengths);
368
369 uint cset_region_length() const { return young_cset_region_length() +
370 old_cset_region_length(); }
371 uint young_cset_region_length() const { return eden_cset_region_length() +
372 survivor_cset_region_length(); }
373
374 double predict_survivor_regions_evac_time() const;
375
376 bool should_update_surv_rate_group_predictors() {
377 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
378 }
379
380 void cset_regions_freed() {
381 bool update = should_update_surv_rate_group_predictors();
382
383 _short_lived_surv_rate_group->all_surviving_words_recorded(update);
384 _survivor_surv_rate_group->all_surviving_words_recorded(update);
385 }
386
387 G1MMUTracker* mmu_tracker() {
388 return _mmu_tracker;
389 }
390
391 const G1MMUTracker* mmu_tracker() const {
392 return _mmu_tracker;
393 }
394
395 double max_pause_time_ms() const {
396 return _mmu_tracker->max_gc_time() * 1000.0;
397 }
398
399 double predict_remark_time_ms() const;
400
401 double predict_cleanup_time_ms() const;
402
403 // Returns an estimate of the survival rate of the region at yg-age
404 // "yg_age".
405 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
406
407 double predict_yg_surv_rate(int age) const;
408
409 double accum_yg_surv_rate_pred(int age) const;
410
411 protected:
412 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
413 virtual double other_time_ms(double pause_time_ms) const;
414
415 double young_other_time_ms() const;
416 double non_young_other_time_ms() const;
417 double constant_other_time_ms(double pause_time_ms) const;
418
419 CollectionSetChooser* cset_chooser() const {
420 return _cset_chooser;
421 }
422
423 private:
424 // Statistics kept per GC stoppage, pause or full.
425 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
426
427 // Add a new GC of the given duration and end time to the record.
428 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
429
430 // The head of the list (via "next_in_collection_set()") representing the
431 // current collection set. Set from the incrementally built collection
432 // set at the start of the pause.
433 HeapRegion* _collection_set;
434
435 // The number of bytes in the collection set before the pause. Set from
436 // the incrementally built collection set at the start of an evacuation
437 // pause, and incremented in finalize_old_cset_part() when adding old regions
438 // (if any) to the collection set.
439 size_t _collection_set_bytes_used_before;
440
441 // The number of bytes copied during the GC.
442 size_t _bytes_copied_during_gc;
443
444 // The associated information that is maintained while the incremental
445 // collection set is being built with young regions. Used to populate
446 // the recorded info for the evacuation pause.
447
448 enum CSetBuildType {
449 Active, // We are actively building the collection set
450 Inactive // We are not actively building the collection set
451 };
452
453 CSetBuildType _inc_cset_build_state;
454
455 // The head of the incrementally built collection set.
456 HeapRegion* _inc_cset_head;
457
458 // The tail of the incrementally built collection set.
459 HeapRegion* _inc_cset_tail;
460
461 // The number of bytes in the incrementally built collection set.
462 // Used to set _collection_set_bytes_used_before at the start of
463 // an evacuation pause.
464 size_t _inc_cset_bytes_used_before;
465
466 // Used to record the highest end of heap region in collection set
467 HeapWord* _inc_cset_max_finger;
468
469 // The RSet lengths recorded for regions in the CSet. It is updated
470 // by the thread that adds a new region to the CSet. We assume that
471 // only one thread can be allocating a new CSet region (currently,
472 // it does so after taking the Heap_lock) hence no need to
473 // synchronize updates to this field.
474 size_t _inc_cset_recorded_rs_lengths;
475
476 // A concurrent refinement thread periodically samples the young
477 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
478 // the RSets grow. Instead of having to synchronize updates to that
479 // field we accumulate them in this field and add it to
480 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
481 ssize_t _inc_cset_recorded_rs_lengths_diffs;
482
483 // The predicted elapsed time it will take to collect the regions in
484 // the CSet. This is updated by the thread that adds a new region to
485 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
486 // MT-safety assumptions.
487 double _inc_cset_predicted_elapsed_time_ms;
488
489 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
490 double _inc_cset_predicted_elapsed_time_ms_diffs;
491
492 // Stash a pointer to the g1 heap.
493 G1CollectedHeap* _g1;
494
495 G1GCPhaseTimes* _phase_times;
496
497 // The ratio of gc time to elapsed time, computed over recent pauses,
498 // and the ratio for just the last pause.
499 double _recent_avg_pause_time_ratio;
500 double _last_pause_time_ratio;
501
502 double recent_avg_pause_time_ratio() const {
503 return _recent_avg_pause_time_ratio;
504 }
505
506 // This set of variables tracks the collector efficiency, in order to
507 // determine whether we should initiate a new marking.
508 double _mark_remark_start_sec;
509 double _mark_cleanup_start_sec;
510
511 // Updates the internal young list maximum and target lengths. Returns the
512 // unbounded young list target length.
513 uint update_young_list_max_and_target_length();
514 uint update_young_list_max_and_target_length(size_t rs_lengths);
515
516 // Update the young list target length either by setting it to the
517 // desired fixed value or by calculating it using G1's pause
518 // prediction model. If no rs_lengths parameter is passed, predict
519 // the RS lengths using the prediction model, otherwise use the
520 // given rs_lengths as the prediction.
521 // Returns the unbounded young list target length.
522 uint update_young_list_target_length(size_t rs_lengths);
523
524 // Calculate and return the minimum desired young list target
525 // length. This is the minimum desired young list length according
526 // to the user's inputs.
527 uint calculate_young_list_desired_min_length(uint base_min_length) const;
528
529 // Calculate and return the maximum desired young list target
530 // length. This is the maximum desired young list length according
531 // to the user's inputs.
532 uint calculate_young_list_desired_max_length() const;
533
534 // Calculate and return the maximum young list target length that
535 // can fit into the pause time goal. The parameters are: rs_lengths
536 // represent the prediction of how large the young RSet lengths will
537 // be, base_min_length is the already existing number of regions in
538 // the young list, min_length and max_length are the desired min and
539 // max young list length according to the user's inputs.
540 uint calculate_young_list_target_length(size_t rs_lengths,
541 uint base_min_length,
542 uint desired_min_length,
543 uint desired_max_length) const;
544
545 // Result of the bounded_young_list_target_length() method, containing both the
546 // bounded as well as the unbounded young list target lengths in this order.
547 typedef Pair<uint, uint, StackObj> YoungTargetLengths;
548 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
549
550 void update_rs_lengths_prediction();
551 void update_rs_lengths_prediction(size_t prediction);
552
553 // Calculate and return chunk size (in number of regions) for parallel
554 // concurrent mark cleanup.
555 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
556
557 // Check whether a given young length (young_length) fits into the
558 // given target pause time and whether the prediction for the amount
559 // of objects to be copied for the given length will fit into the
560 // given free space (expressed by base_free_regions). It is used by
561 // calculate_young_list_target_length().
562 bool predict_will_fit(uint young_length, double base_time_ms,
563 uint base_free_regions, double target_pause_time_ms) const;
564
565 // Calculate the minimum number of old regions we'll add to the CSet
566 // during a mixed GC.
567 uint calc_min_old_cset_length() const;
568
569 // Calculate the maximum number of old regions we'll add to the CSet
570 // during a mixed GC.
571 uint calc_max_old_cset_length() const;
572
573 // Returns the given amount of uncollected reclaimable space
574 // as a percentage of the current heap capacity.
575 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
576
577 // Sets up marking if proper conditions are met.
578 void maybe_start_marking();
579
580 // The kind of STW pause.
581 enum PauseKind {
582 FullGC,
583 YoungOnlyGC,
584 MixedGC,
585 LastYoungGC,
586 InitialMarkGC,
587 Cleanup,
588 Remark
589 };
590
591 // Calculate PauseKind from internal state.
592 PauseKind young_gc_pause_kind() const;
593 // Record the given STW pause with the given start and end times (in s).
594 void record_pause(PauseKind kind, double start, double end);
595 // Indicate that we aborted marking before doing any mixed GCs.
596 void abort_time_to_mixed_tracking();
597 public:
598
599 G1CollectorPolicy();
600
601 virtual ~G1CollectorPolicy();
602
603 virtual G1CollectorPolicy* as_g1_policy() { return this; }
604
605 G1CollectorState* collector_state() const;
606
607 G1GCPhaseTimes* phase_times() const { return _phase_times; }
608
609 // Check the current value of the young list RSet lengths and
610 // compare it against the last prediction. If the current value is
611 // higher, recalculate the young list target length prediction.
612 void revise_young_list_target_length_if_necessary();
613
614 // This should be called after the heap is resized.
615 void record_new_heap_size(uint new_number_of_regions);
616
617 void init();
618
619 virtual void note_gc_start(uint num_active_workers);
620
621 // Create jstat counters for the policy.
622 virtual void initialize_gc_policy_counters();
623
624 virtual HeapWord* mem_allocate_work(size_t size,
625 bool is_tlab,
626 bool* gc_overhead_limit_was_exceeded);
627
628 // This method controls how a collector handles one or more
629 // of its generations being fully allocated.
630 virtual HeapWord* satisfy_failed_allocation(size_t size,
631 bool is_tlab);
632
633 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
634
635 bool about_to_start_mixed_phase() const;
636
637 // Record the start and end of an evacuation pause.
638 void record_collection_pause_start(double start_time_sec);
639 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc);
640
641 // Record the start and end of a full collection.
642 void record_full_collection_start();
643 void record_full_collection_end();
644
645 // Must currently be called while the world is stopped.
646 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
647
648 // Record start and end of remark.
649 void record_concurrent_mark_remark_start();
650 void record_concurrent_mark_remark_end();
651
652 // Record start, end, and completion of cleanup.
653 void record_concurrent_mark_cleanup_start();
654 void record_concurrent_mark_cleanup_end();
655 void record_concurrent_mark_cleanup_completed();
656
657 virtual void print_phases();
658
659 void record_stop_world_start();
660 void record_concurrent_pause();
661
662 // Record how much space we copied during a GC. This is typically
663 // called when a GC alloc region is being retired.
664 void record_bytes_copied_during_gc(size_t bytes) {
665 _bytes_copied_during_gc += bytes;
666 }
667
668 // The amount of space we copied during a GC.
669 size_t bytes_copied_during_gc() const {
670 return _bytes_copied_during_gc;
671 }
672
673 size_t collection_set_bytes_used_before() const {
674 return _collection_set_bytes_used_before;
675 }
676
677 // Determine whether there are candidate regions so that the
678 // next GC should be mixed. The two action strings are used
679 // in the ergo output when the method returns true or false.
680 bool next_gc_should_be_mixed(const char* true_action_str,
681 const char* false_action_str) const;
682
683 // Choose a new collection set. Marks the chosen regions as being
684 // "in_collection_set", and links them together. The head and number of
685 // the collection set are available via access methods.
686 double finalize_young_cset_part(double target_pause_time_ms);
687 virtual void finalize_old_cset_part(double time_remaining_ms);
688
689 // The head of the list (via "next_in_collection_set()") representing the
690 // current collection set.
691 HeapRegion* collection_set() { return _collection_set; }
692
693 void clear_collection_set() { _collection_set = NULL; }
694
695 // Add old region "hr" to the CSet.
696 void add_old_region_to_cset(HeapRegion* hr);
697
698 // Incremental CSet Support
699
700 // The head of the incrementally built collection set.
701 HeapRegion* inc_cset_head() { return _inc_cset_head; }
702
703 // The tail of the incrementally built collection set.
704 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
705
706 // Initialize incremental collection set info.
707 void start_incremental_cset_building();
708
709 // Perform any final calculations on the incremental CSet fields
710 // before we can use them.
711 void finalize_incremental_cset_building();
712
713 void clear_incremental_cset() {
714 _inc_cset_head = NULL;
715 _inc_cset_tail = NULL;
716 }
717
718 // Stop adding regions to the incremental collection set
719 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
720
721 // Add information about hr to the aggregated information for the
722 // incrementally built collection set.
723 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
724
725 // Update information about hr in the aggregated information for
726 // the incrementally built collection set.
727 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
728
729 private:
730 // Update the incremental cset information when adding a region
731 // (should not be called directly).
732 void add_region_to_incremental_cset_common(HeapRegion* hr);
733
734 // Set the state to start a concurrent marking cycle and clear
735 // _initiate_conc_mark_if_possible because it has now been
736 // acted on.
737 void initiate_conc_mark();
738
739 public:
740 // Add hr to the LHS of the incremental collection set.
741 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
742
743 // Add hr to the RHS of the incremental collection set.
744 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
745
746 #ifndef PRODUCT
747 void print_collection_set(HeapRegion* list_head, outputStream* st);
748 #endif // !PRODUCT
749
750 // This sets the initiate_conc_mark_if_possible() flag to start a
751 // new cycle, as long as we are not already in one. It's best if it
752 // is called during a safepoint when the test whether a cycle is in
753 // progress or not is stable.
754 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
755
756 // This is called at the very beginning of an evacuation pause (it
757 // has to be the first thing that the pause does). If
758 // initiate_conc_mark_if_possible() is true, and the concurrent
759 // marking thread has completed its work during the previous cycle,
760 // it will set during_initial_mark_pause() to so that the pause does
761 // the initial-mark work and start a marking cycle.
762 void decide_on_conc_mark_initiation();
763
764 // If an expansion would be appropriate, because recent GC overhead had
765 // exceeded the desired limit, return an amount to expand by.
766 virtual size_t expansion_amount();
767
768 // Clear ratio tracking data used by expansion_amount().
769 void clear_ratio_check_data();
770
771 // Print tracing information.
772 void print_tracing_info() const;
773
774 // Print stats on young survival ratio
775 void print_yg_surv_rate_info() const;
776
777 void finished_recalculating_age_indexes(bool is_survivors) {
778 if (is_survivors) {
779 _survivor_surv_rate_group->finished_recalculating_age_indexes();
780 } else {
781 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
782 }
783 // do that for any other surv rate groups
784 }
785
786 size_t young_list_target_length() const { return _young_list_target_length; }
787
788 bool is_young_list_full() const;
789
790 bool can_expand_young_list() const;
791
792 uint young_list_max_length() const {
793 return _young_list_max_length;
794 }
795
796 bool adaptive_young_list_length() const {
797 return _young_gen_sizer->adaptive_young_list_length();
798 }
799
800 virtual bool should_process_references() const {
801 return true;
802 }
803
804 private:
805 //
806 // Survivor regions policy.
807 //
808
809 // Current tenuring threshold, set to 0 if the collector reaches the
810 // maximum amount of survivors regions.
811 uint _tenuring_threshold;
812
813 // The limit on the number of regions allocated for survivors.
814 uint _max_survivor_regions;
815
816 // For reporting purposes.
817 // The value of _heap_bytes_before_gc is also used to calculate
818 // the cost of copying.
819
820 // The amount of survivor regions after a collection.
821 uint _recorded_survivor_regions;
822 // List of survivor regions.
823 HeapRegion* _recorded_survivor_head;
824 HeapRegion* _recorded_survivor_tail;
825
826 AgeTable _survivors_age_table;
827
828 public:
829 uint tenuring_threshold() const { return _tenuring_threshold; }
830
831 uint max_survivor_regions() {
832 return _max_survivor_regions;
833 }
834
835 void note_start_adding_survivor_regions() {
836 _survivor_surv_rate_group->start_adding_regions();
837 }
838
839 void note_stop_adding_survivor_regions() {
840 _survivor_surv_rate_group->stop_adding_regions();
841 }
842
843 void record_survivor_regions(uint regions,
844 HeapRegion* head,
845 HeapRegion* tail) {
846 _recorded_survivor_regions = regions;
847 _recorded_survivor_head = head;
848 _recorded_survivor_tail = tail;
849 }
850
851 uint recorded_survivor_regions() const {
852 return _recorded_survivor_regions;
853 }
854
855 void record_age_table(AgeTable* age_table) {
856 _survivors_age_table.merge(age_table);
857 }
858
859 void update_max_gc_locker_expansion();
860
861 // Calculates survivor space parameters.
862 void update_survivors_policy();
863
864 virtual void post_heap_initialize();
865 };
866
867 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP