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 // There are three command line options related to the young gen size:
48 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
49 // just a short form for NewSize==MaxNewSize). G1 will use its internal
50 // heuristics to calculate the actual young gen size, so these options
51 // basically only limit the range within which G1 can pick a young gen
52 // size. Also, these are general options taking byte sizes. G1 will
53 // internally work with a number of regions instead. So, some rounding
54 // will occur.
55 //
56 // If nothing related to the the young gen size is set on the command
57 // line we should allow the young gen to be between G1NewSizePercent
58 // and G1MaxNewSizePercent of the heap size. This means that every time
59 // the heap size changes, the limits for the young gen size will be
60 // recalculated.
61 //
62 // If only -XX:NewSize is set we should use the specified value as the
63 // minimum size for young gen. Still using G1MaxNewSizePercent of the
64 // heap as maximum.
65 //
66 // If only -XX:MaxNewSize is set we should use the specified value as the
67 // maximum size for young gen. Still using G1NewSizePercent of the heap
68 // as minimum.
69 //
70 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
71 // No updates when the heap size changes. There is a special case when
72 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
73 // different heuristic for calculating the collection set when we do mixed
74 // collection.
75 //
76 // If only -XX:NewRatio is set we should use the specified ratio of the heap
77 // as both min and max. This will be interpreted as "fixed" just like the
78 // NewSize==MaxNewSize case above. But we will update the min and max
79 // every time the heap size changes.
80 //
81 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
82 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
83 class G1YoungGenSizer : public CHeapObj<mtGC> {
84 private:
85 enum SizerKind {
86 SizerDefaults,
87 SizerNewSizeOnly,
88 SizerMaxNewSizeOnly,
89 SizerMaxAndNewSize,
90 SizerNewRatio
91 };
92 SizerKind _sizer_kind;
93 uint _min_desired_young_length;
94 uint _max_desired_young_length;
95 bool _adaptive_size;
96 uint calculate_default_min_length(uint new_number_of_heap_regions);
97 uint calculate_default_max_length(uint new_number_of_heap_regions);
98
99 // Update the given values for minimum and maximum young gen length in regions
100 // given the number of heap regions depending on the kind of sizing algorithm.
101 void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length);
102
103 public:
104 G1YoungGenSizer();
105 // Calculate the maximum length of the young gen given the number of regions
106 // depending on the sizing algorithm.
107 uint max_young_length(uint number_of_heap_regions);
108
109 void heap_size_changed(uint new_number_of_heap_regions);
110 uint min_desired_young_length() {
111 return _min_desired_young_length;
112 }
113 uint max_desired_young_length() {
114 return _max_desired_young_length;
115 }
116
117 bool adaptive_young_list_length() const {
118 return _adaptive_size;
119 }
120 };
121
122 class G1CollectorPolicy: public CollectorPolicy {
123 private:
124 G1IHOPControl* _ihop_control;
125
126 G1IHOPControl* create_ihop_control() const;
127 // Update the IHOP control with necessary statistics.
128 void update_ihop_prediction(double mutator_time_s,
129 size_t mutator_alloc_bytes,
130 size_t young_gen_size);
131 void report_ihop_statistics();
132
133 G1Predictions _predictor;
134
135 double get_new_prediction(TruncatedSeq const* seq) const;
136 size_t get_new_size_prediction(TruncatedSeq const* seq) const;
137
138 G1MMUTracker* _mmu_tracker;
139
140 void initialize_alignments();
141 void initialize_flags();
142
143 CollectionSetChooser* _cset_chooser;
144
145 double _full_collection_start_sec;
146
147 // These exclude marking times.
148 TruncatedSeq* _recent_gc_times_ms;
149
150 TruncatedSeq* _concurrent_mark_remark_times_ms;
151 TruncatedSeq* _concurrent_mark_cleanup_times_ms;
152
153 // Ratio check data for determining if heap growth is necessary.
154 uint _ratio_over_threshold_count;
155 double _ratio_over_threshold_sum;
156 uint _pauses_since_start;
157
158 uint _young_list_target_length;
159 uint _young_list_fixed_length;
160
161 // The max number of regions we can extend the eden by while the GC
162 // locker is active. This should be >= _young_list_target_length;
163 uint _young_list_max_length;
164
165 SurvRateGroup* _short_lived_surv_rate_group;
166 SurvRateGroup* _survivor_surv_rate_group;
167 // add here any more surv rate groups
168
169 double _gc_overhead_perc;
170
171 double _reserve_factor;
172 uint _reserve_regions;
173
174 enum PredictionConstants {
175 TruncatedSeqLength = 10,
176 NumPrevPausesForHeuristics = 10,
177 // MinOverThresholdForGrowth must be less than NumPrevPausesForHeuristics,
178 // representing the minimum number of pause time ratios that exceed
179 // GCTimeRatio before a heap expansion will be triggered.
180 MinOverThresholdForGrowth = 4
181 };
182
183 TruncatedSeq* _alloc_rate_ms_seq;
184 double _prev_collection_pause_end_ms;
185
186 TruncatedSeq* _rs_length_diff_seq;
187 TruncatedSeq* _cost_per_card_ms_seq;
188 TruncatedSeq* _cost_scan_hcc_seq;
189 TruncatedSeq* _young_cards_per_entry_ratio_seq;
190 TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
191 TruncatedSeq* _cost_per_entry_ms_seq;
192 TruncatedSeq* _mixed_cost_per_entry_ms_seq;
193 TruncatedSeq* _cost_per_byte_ms_seq;
194 TruncatedSeq* _constant_other_time_ms_seq;
195 TruncatedSeq* _young_other_cost_per_region_ms_seq;
196 TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
197
198 TruncatedSeq* _pending_cards_seq;
199 TruncatedSeq* _rs_lengths_seq;
200
201 TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
202
203 G1YoungGenSizer* _young_gen_sizer;
204
205 uint _eden_cset_region_length;
206 uint _survivor_cset_region_length;
207 uint _old_cset_region_length;
208
209 void init_cset_region_lengths(uint eden_cset_region_length,
210 uint survivor_cset_region_length);
211
212 uint eden_cset_region_length() const { return _eden_cset_region_length; }
213 uint survivor_cset_region_length() const { return _survivor_cset_region_length; }
214 uint old_cset_region_length() const { return _old_cset_region_length; }
215
216 uint _free_regions_at_end_of_collection;
217
218 size_t _recorded_rs_lengths;
219 size_t _max_rs_lengths;
220
221 size_t _rs_lengths_prediction;
222
223 #ifndef PRODUCT
224 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
225 #endif // PRODUCT
226
227 void adjust_concurrent_refinement(double update_rs_time,
228 double update_rs_processed_buffers,
229 double goal_ms);
230
231 double _pause_time_target_ms;
232
233 size_t _pending_cards;
234
235 // The amount of allocated bytes in old gen during the last mutator and the following
236 // young GC phase.
237 size_t _bytes_allocated_in_old_since_last_gc;
238
239 G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
240 public:
241 const G1Predictions& predictor() const { return _predictor; }
242
243 // Add the given number of bytes to the total number of allocated bytes in the old gen.
244 void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
245
246 // Accessors
247
248 void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
249 hr->set_eden();
250 hr->install_surv_rate_group(_short_lived_surv_rate_group);
251 hr->set_young_index_in_cset(young_index_in_cset);
252 }
253
254 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
255 assert(hr->is_survivor(), "pre-condition");
256 hr->install_surv_rate_group(_survivor_surv_rate_group);
257 hr->set_young_index_in_cset(young_index_in_cset);
258 }
259
260 #ifndef PRODUCT
261 bool verify_young_ages();
262 #endif // PRODUCT
263
264 void record_max_rs_lengths(size_t rs_lengths) {
265 _max_rs_lengths = rs_lengths;
266 }
267
268 size_t predict_rs_length_diff() const;
269
270 double predict_alloc_rate_ms() const;
271
272 double predict_cost_per_card_ms() const;
273
274 double predict_scan_hcc_ms() const;
275
276 double predict_rs_update_time_ms(size_t pending_cards) const;
277
278 double predict_young_cards_per_entry_ratio() const;
279
280 double predict_mixed_cards_per_entry_ratio() const;
281
282 size_t predict_young_card_num(size_t rs_length) const;
283
284 size_t predict_non_young_card_num(size_t rs_length) const;
285
286 double predict_rs_scan_time_ms(size_t card_num) const;
287
288 double predict_mixed_rs_scan_time_ms(size_t card_num) const;
289
290 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
291
292 double predict_object_copy_time_ms(size_t bytes_to_copy) const;
293
294 double predict_constant_other_time_ms() const;
295
296 double predict_young_other_time_ms(size_t young_num) const;
297
298 double predict_non_young_other_time_ms(size_t non_young_num) const;
299
300 double predict_base_elapsed_time_ms(size_t pending_cards) const;
301 double predict_base_elapsed_time_ms(size_t pending_cards,
302 size_t scanned_cards) const;
303 size_t predict_bytes_to_copy(HeapRegion* hr) const;
304 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
305
306 void set_recorded_rs_lengths(size_t rs_lengths);
307
308 uint cset_region_length() const { return young_cset_region_length() +
309 old_cset_region_length(); }
310 uint young_cset_region_length() const { return eden_cset_region_length() +
311 survivor_cset_region_length(); }
312
313 double predict_survivor_regions_evac_time() const;
314
315 bool should_update_surv_rate_group_predictors() {
316 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
317 }
318
319 void cset_regions_freed() {
320 bool update = should_update_surv_rate_group_predictors();
321
322 _short_lived_surv_rate_group->all_surviving_words_recorded(update);
323 _survivor_surv_rate_group->all_surviving_words_recorded(update);
324 }
325
326 G1MMUTracker* mmu_tracker() {
327 return _mmu_tracker;
328 }
329
330 const G1MMUTracker* mmu_tracker() const {
331 return _mmu_tracker;
332 }
333
334 double max_pause_time_ms() const {
335 return _mmu_tracker->max_gc_time() * 1000.0;
336 }
337
338 double predict_remark_time_ms() const;
339
340 double predict_cleanup_time_ms() const;
341
342 // Returns an estimate of the survival rate of the region at yg-age
343 // "yg_age".
344 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
345
346 double predict_yg_surv_rate(int age) const;
347
348 double accum_yg_surv_rate_pred(int age) const;
349
350 protected:
351 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
352 virtual double other_time_ms(double pause_time_ms) const;
353
354 double young_other_time_ms() const;
355 double non_young_other_time_ms() const;
356 double constant_other_time_ms(double pause_time_ms) const;
357
358 CollectionSetChooser* cset_chooser() const {
359 return _cset_chooser;
360 }
361
362 private:
363 // Statistics kept per GC stoppage, pause or full.
364 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
365
366 // Add a new GC of the given duration and end time to the record.
367 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
368
369 // The head of the list (via "next_in_collection_set()") representing the
370 // current collection set. Set from the incrementally built collection
371 // set at the start of the pause.
372 HeapRegion* _collection_set;
373
374 // The number of bytes in the collection set before the pause. Set from
375 // the incrementally built collection set at the start of an evacuation
376 // pause, and incremented in finalize_old_cset_part() when adding old regions
377 // (if any) to the collection set.
378 size_t _collection_set_bytes_used_before;
379
380 // The number of bytes copied during the GC.
381 size_t _bytes_copied_during_gc;
382
383 // The associated information that is maintained while the incremental
384 // collection set is being built with young regions. Used to populate
385 // the recorded info for the evacuation pause.
386
387 enum CSetBuildType {
388 Active, // We are actively building the collection set
389 Inactive // We are not actively building the collection set
390 };
391
392 CSetBuildType _inc_cset_build_state;
393
394 // The head of the incrementally built collection set.
395 HeapRegion* _inc_cset_head;
396
397 // The tail of the incrementally built collection set.
398 HeapRegion* _inc_cset_tail;
399
400 // The number of bytes in the incrementally built collection set.
401 // Used to set _collection_set_bytes_used_before at the start of
402 // an evacuation pause.
403 size_t _inc_cset_bytes_used_before;
404
405 // Used to record the highest end of heap region in collection set
406 HeapWord* _inc_cset_max_finger;
407
408 // The RSet lengths recorded for regions in the CSet. It is updated
409 // by the thread that adds a new region to the CSet. We assume that
410 // only one thread can be allocating a new CSet region (currently,
411 // it does so after taking the Heap_lock) hence no need to
412 // synchronize updates to this field.
413 size_t _inc_cset_recorded_rs_lengths;
414
415 // A concurrent refinement thread periodically samples the young
416 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
417 // the RSets grow. Instead of having to synchronize updates to that
418 // field we accumulate them in this field and add it to
419 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
420 ssize_t _inc_cset_recorded_rs_lengths_diffs;
421
422 // The predicted elapsed time it will take to collect the regions in
423 // the CSet. This is updated by the thread that adds a new region to
424 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
425 // MT-safety assumptions.
426 double _inc_cset_predicted_elapsed_time_ms;
427
428 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
429 double _inc_cset_predicted_elapsed_time_ms_diffs;
430
431 // Stash a pointer to the g1 heap.
432 G1CollectedHeap* _g1;
433
434 G1GCPhaseTimes* _phase_times;
435
436 // The ratio of gc time to elapsed time, computed over recent pauses,
437 // and the ratio for just the last pause.
438 double _recent_avg_pause_time_ratio;
439 double _last_pause_time_ratio;
440
441 double recent_avg_pause_time_ratio() const {
442 return _recent_avg_pause_time_ratio;
443 }
444
445 // This set of variables tracks the collector efficiency, in order to
446 // determine whether we should initiate a new marking.
447 double _mark_remark_start_sec;
448 double _mark_cleanup_start_sec;
449
450 // Updates the internal young list maximum and target lengths. Returns the
451 // unbounded young list target length.
452 uint update_young_list_max_and_target_length();
453 uint update_young_list_max_and_target_length(size_t rs_lengths);
454
455 // Update the young list target length either by setting it to the
456 // desired fixed value or by calculating it using G1's pause
457 // prediction model. If no rs_lengths parameter is passed, predict
458 // the RS lengths using the prediction model, otherwise use the
459 // given rs_lengths as the prediction.
460 // Returns the unbounded young list target length.
461 uint update_young_list_target_length(size_t rs_lengths);
462
463 // Calculate and return the minimum desired young list target
464 // length. This is the minimum desired young list length according
465 // to the user's inputs.
466 uint calculate_young_list_desired_min_length(uint base_min_length) const;
467
468 // Calculate and return the maximum desired young list target
469 // length. This is the maximum desired young list length according
470 // to the user's inputs.
471 uint calculate_young_list_desired_max_length() const;
472
473 // Calculate and return the maximum young list target length that
474 // can fit into the pause time goal. The parameters are: rs_lengths
475 // represent the prediction of how large the young RSet lengths will
476 // be, base_min_length is the already existing number of regions in
477 // the young list, min_length and max_length are the desired min and
478 // max young list length according to the user's inputs.
479 uint calculate_young_list_target_length(size_t rs_lengths,
480 uint base_min_length,
481 uint desired_min_length,
482 uint desired_max_length) const;
483
484 // Result of the bounded_young_list_target_length() method, containing both the
485 // bounded as well as the unbounded young list target lengths in this order.
486 typedef Pair<uint, uint, StackObj> YoungTargetLengths;
487 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
488
489 void update_rs_lengths_prediction();
490 void update_rs_lengths_prediction(size_t prediction);
491
492 // Calculate and return chunk size (in number of regions) for parallel
493 // concurrent mark cleanup.
494 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
495
496 // Check whether a given young length (young_length) fits into the
497 // given target pause time and whether the prediction for the amount
498 // of objects to be copied for the given length will fit into the
499 // given free space (expressed by base_free_regions). It is used by
500 // calculate_young_list_target_length().
501 bool predict_will_fit(uint young_length, double base_time_ms,
502 uint base_free_regions, double target_pause_time_ms) const;
503
504 // Calculate the minimum number of old regions we'll add to the CSet
505 // during a mixed GC.
506 uint calc_min_old_cset_length() const;
507
508 // Calculate the maximum number of old regions we'll add to the CSet
509 // during a mixed GC.
510 uint calc_max_old_cset_length() const;
511
512 // Returns the given amount of uncollected reclaimable space
513 // as a percentage of the current heap capacity.
514 double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
515
516 // Sets up marking if proper conditions are met.
517 void maybe_start_marking();
518
519 // The kind of STW pause.
520 enum PauseKind {
521 FullGC,
522 YoungOnlyGC,
523 MixedGC,
524 LastYoungGC,
525 InitialMarkGC,
526 Cleanup,
527 Remark
528 };
529
530 // Calculate PauseKind from internal state.
531 PauseKind young_gc_pause_kind() const;
532 // Record the given STW pause with the given start and end times (in s).
533 void record_pause(PauseKind kind, double start, double end);
534 // Indicate that we aborted marking before doing any mixed GCs.
535 void abort_time_to_mixed_tracking();
536 public:
537
538 G1CollectorPolicy();
539
540 virtual ~G1CollectorPolicy();
541
542 virtual G1CollectorPolicy* as_g1_policy() { return this; }
543
544 G1CollectorState* collector_state() const;
545
546 G1GCPhaseTimes* phase_times() const { return _phase_times; }
547
548 // Check the current value of the young list RSet lengths and
549 // compare it against the last prediction. If the current value is
550 // higher, recalculate the young list target length prediction.
551 void revise_young_list_target_length_if_necessary();
552
553 // This should be called after the heap is resized.
554 void record_new_heap_size(uint new_number_of_regions);
555
556 void init();
557
558 virtual void note_gc_start(uint num_active_workers);
559
560 // Create jstat counters for the policy.
561 virtual void initialize_gc_policy_counters();
562
563 virtual HeapWord* mem_allocate_work(size_t size,
564 bool is_tlab,
565 bool* gc_overhead_limit_was_exceeded);
566
567 // This method controls how a collector handles one or more
568 // of its generations being fully allocated.
569 virtual HeapWord* satisfy_failed_allocation(size_t size,
570 bool is_tlab);
571
572 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
573
574 bool about_to_start_mixed_phase() const;
575
576 // Record the start and end of an evacuation pause.
577 void record_collection_pause_start(double start_time_sec);
578 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc);
579
580 // Record the start and end of a full collection.
581 void record_full_collection_start();
582 void record_full_collection_end();
583
584 // Must currently be called while the world is stopped.
585 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
586
587 // Record start and end of remark.
588 void record_concurrent_mark_remark_start();
589 void record_concurrent_mark_remark_end();
590
591 // Record start, end, and completion of cleanup.
592 void record_concurrent_mark_cleanup_start();
593 void record_concurrent_mark_cleanup_end();
594 void record_concurrent_mark_cleanup_completed();
595
596 virtual void print_phases();
597
598 // Record how much space we copied during a GC. This is typically
599 // called when a GC alloc region is being retired.
600 void record_bytes_copied_during_gc(size_t bytes) {
601 _bytes_copied_during_gc += bytes;
602 }
603
604 // The amount of space we copied during a GC.
605 size_t bytes_copied_during_gc() const {
606 return _bytes_copied_during_gc;
607 }
608
609 size_t collection_set_bytes_used_before() const {
610 return _collection_set_bytes_used_before;
611 }
612
613 // Determine whether there are candidate regions so that the
614 // next GC should be mixed. The two action strings are used
615 // in the ergo output when the method returns true or false.
616 bool next_gc_should_be_mixed(const char* true_action_str,
617 const char* false_action_str) const;
618
619 // Choose a new collection set. Marks the chosen regions as being
620 // "in_collection_set", and links them together. The head and number of
621 // the collection set are available via access methods.
622 double finalize_young_cset_part(double target_pause_time_ms);
623 virtual void finalize_old_cset_part(double time_remaining_ms);
624
625 // The head of the list (via "next_in_collection_set()") representing the
626 // current collection set.
627 HeapRegion* collection_set() { return _collection_set; }
628
629 void clear_collection_set() { _collection_set = NULL; }
630
631 // Add old region "hr" to the CSet.
632 void add_old_region_to_cset(HeapRegion* hr);
633
634 // Incremental CSet Support
635
636 // The head of the incrementally built collection set.
637 HeapRegion* inc_cset_head() { return _inc_cset_head; }
638
639 // The tail of the incrementally built collection set.
640 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
641
642 // Initialize incremental collection set info.
643 void start_incremental_cset_building();
644
645 // Perform any final calculations on the incremental CSet fields
646 // before we can use them.
647 void finalize_incremental_cset_building();
648
649 void clear_incremental_cset() {
650 _inc_cset_head = NULL;
651 _inc_cset_tail = NULL;
652 }
653
654 // Stop adding regions to the incremental collection set
655 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
656
657 // Add information about hr to the aggregated information for the
658 // incrementally built collection set.
659 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
660
661 // Update information about hr in the aggregated information for
662 // the incrementally built collection set.
663 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
664
665 private:
666 // Update the incremental cset information when adding a region
667 // (should not be called directly).
668 void add_region_to_incremental_cset_common(HeapRegion* hr);
669
670 // Set the state to start a concurrent marking cycle and clear
671 // _initiate_conc_mark_if_possible because it has now been
672 // acted on.
673 void initiate_conc_mark();
674
675 public:
676 // Add hr to the LHS of the incremental collection set.
677 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
678
679 // Add hr to the RHS of the incremental collection set.
680 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
681
682 #ifndef PRODUCT
683 void print_collection_set(HeapRegion* list_head, outputStream* st);
684 #endif // !PRODUCT
685
686 // This sets the initiate_conc_mark_if_possible() flag to start a
687 // new cycle, as long as we are not already in one. It's best if it
688 // is called during a safepoint when the test whether a cycle is in
689 // progress or not is stable.
690 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
691
692 // This is called at the very beginning of an evacuation pause (it
693 // has to be the first thing that the pause does). If
694 // initiate_conc_mark_if_possible() is true, and the concurrent
695 // marking thread has completed its work during the previous cycle,
696 // it will set during_initial_mark_pause() to so that the pause does
697 // the initial-mark work and start a marking cycle.
698 void decide_on_conc_mark_initiation();
699
700 // If an expansion would be appropriate, because recent GC overhead had
701 // exceeded the desired limit, return an amount to expand by.
702 virtual size_t expansion_amount();
703
704 // Clear ratio tracking data used by expansion_amount().
705 void clear_ratio_check_data();
706
707 // Print stats on young survival ratio
708 void print_yg_surv_rate_info() const;
709
710 void finished_recalculating_age_indexes(bool is_survivors) {
711 if (is_survivors) {
712 _survivor_surv_rate_group->finished_recalculating_age_indexes();
713 } else {
714 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
715 }
716 // do that for any other surv rate groups
717 }
718
719 size_t young_list_target_length() const { return _young_list_target_length; }
720
721 bool is_young_list_full() const;
722
723 bool can_expand_young_list() const;
724
725 uint young_list_max_length() const {
726 return _young_list_max_length;
727 }
728
729 bool adaptive_young_list_length() const {
730 return _young_gen_sizer->adaptive_young_list_length();
731 }
732
733 virtual bool should_process_references() const {
734 return true;
735 }
736
737 private:
738 //
739 // Survivor regions policy.
740 //
741
742 // Current tenuring threshold, set to 0 if the collector reaches the
743 // maximum amount of survivors regions.
744 uint _tenuring_threshold;
745
746 // The limit on the number of regions allocated for survivors.
747 uint _max_survivor_regions;
748
749 // For reporting purposes.
750 // The value of _heap_bytes_before_gc is also used to calculate
751 // the cost of copying.
752
753 // The amount of survivor regions after a collection.
754 uint _recorded_survivor_regions;
755 // List of survivor regions.
756 HeapRegion* _recorded_survivor_head;
757 HeapRegion* _recorded_survivor_tail;
758
759 AgeTable _survivors_age_table;
760
761 public:
762 uint tenuring_threshold() const { return _tenuring_threshold; }
763
764 uint max_survivor_regions() {
765 return _max_survivor_regions;
766 }
767
768 static const uint REGIONS_UNLIMITED = (uint) -1;
769
770 uint max_regions(InCSetState dest) const {
771 switch (dest.value()) {
772 case InCSetState::Young:
773 return _max_survivor_regions;
774 case InCSetState::Old:
775 return REGIONS_UNLIMITED;
776 default:
777 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value());
778 break;
779 }
780 // keep some compilers happy
781 return 0;
782 }
783
784 void note_start_adding_survivor_regions() {
785 _survivor_surv_rate_group->start_adding_regions();
786 }
787
788 void note_stop_adding_survivor_regions() {
789 _survivor_surv_rate_group->stop_adding_regions();
790 }
791
792 void record_survivor_regions(uint regions,
793 HeapRegion* head,
794 HeapRegion* tail) {
795 _recorded_survivor_regions = regions;
796 _recorded_survivor_head = head;
797 _recorded_survivor_tail = tail;
798 }
799
800 uint recorded_survivor_regions() const {
801 return _recorded_survivor_regions;
802 }
803
804 void record_age_table(AgeTable* age_table) {
805 _survivors_age_table.merge(age_table);
806 }
807
808 void update_max_gc_locker_expansion();
809
810 // Calculates survivor space parameters.
811 void update_survivors_policy();
812
813 virtual void post_heap_initialize();
814 };
815
816 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP