43 // * when to collect.
44
45 class HeapRegion;
46 class G1CollectionSet;
47 class G1CollectionSetCandidates;
48 class G1CollectionSetChooser;
49 class G1IHOPControl;
50 class G1Analytics;
51 class G1SurvivorRegions;
52 class G1YoungGenSizer;
53 class GCPolicyCounters;
54 class STWGCTimer;
55
56 class G1Policy: public CHeapObj<mtGC> {
57 private:
58
59 static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
60 // Update the IHOP control with necessary statistics.
61 void update_ihop_prediction(double mutator_time_s,
62 size_t mutator_alloc_bytes,
63 size_t young_gen_size,
64 bool this_gc_was_young_only);
65 void report_ihop_statistics();
66
67 G1Predictions _predictor;
68 G1Analytics* _analytics;
69 G1RemSetTrackingPolicy _remset_tracker;
70 G1MMUTracker* _mmu_tracker;
71 G1IHOPControl* _ihop_control;
72
73 GCPolicyCounters* _policy_counters;
74
75 double _full_collection_start_sec;
76
77 jlong _collection_pause_end_millis;
78
79 uint _young_list_target_length;
80
81 // The max number of regions we can extend the eden by while the GC
82 // locker is active. This should be >= _young_list_target_length;
83 uint _young_list_max_length;
84
85 // The survivor rate groups below must be initialized after the predictor because they
86 // indirectly use it through the "this" object passed to their constructor.
87 G1SurvRateGroup* _eden_surv_rate_group;
88 G1SurvRateGroup* _survivor_surv_rate_group;
89
90 double _reserve_factor;
91 // This will be set when the heap is expanded
92 // for the first time during initialization.
93 uint _reserve_regions;
94
95 G1YoungGenSizer* _young_gen_sizer;
96
97 uint _free_regions_at_end_of_collection;
98
175
176 double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
177 double other_time_ms(double pause_time_ms) const;
178
179 double young_other_time_ms() const;
180 double non_young_other_time_ms() const;
181 double constant_other_time_ms(double pause_time_ms) const;
182
183 G1CollectionSetChooser* cset_chooser() const;
184
185 // Stash a pointer to the g1 heap.
186 G1CollectedHeap* _g1h;
187
188 G1GCPhaseTimes* _phase_times;
189
190 // This set of variables tracks the collector efficiency, in order to
191 // determine whether we should initiate a new marking.
192 double _mark_remark_start_sec;
193 double _mark_cleanup_start_sec;
194
195 // Updates the internal young gen maximum and target lengths. Returns the
196 // unbounded young target length. If no rs_length parameter is passed,
197 // predict the RS length using the prediction model, otherwise use the
198 // given rs_length as the prediction.
199 uint update_young_max_and_target_length();
200 uint update_young_max_and_target_length(size_t rs_length);
201
202 // Update the young list target length either by setting it to the
203 // desired fixed value or by calculating it using G1's pause
204 // prediction model.
205 // Returns the unbounded young list target length.
206 uint update_young_target_length(size_t rs_length);
207
208 // Calculate and return the minimum desired eden length based on the MMU target.
209 uint calculate_desired_eden_length_by_mmu() const;
210
211 // Calculate and return the desired eden length that can fit into the pause time goal.
212 // The parameters are: rs_length represents the prediction of how large the
213 // young RSet lengths will be, min_eden_length and max_eden_length are the bounds
214 // (inclusive) within eden can grow.
215 uint calculate_desired_eden_length_by_pause(double base_time_ms,
216 uint min_eden_length,
217 uint max_eden_length) const;
218
219 // Calculates the desired eden length before mixed gc so that after adding the
220 // minimum amount of old gen regions from the collection set, the eden fits into
221 // the pause time goal.
222 uint calculate_desired_eden_length_before_mixed(double survivor_base_time_ms,
223 uint min_eden_length,
224 uint max_eden_length) const;
225
226 // Calculate desired young length based on current situation without taking actually
227 // available free regions into account.
228 uint calculate_young_desired_length(size_t rs_length) const;
229 // Limit the given desired young length to available free regions.
230 uint calculate_young_target_length(uint desired_young_length) const;
231
232 void update_rs_length_prediction();
233 void update_rs_length_prediction(size_t prediction);
234
235 size_t predict_bytes_to_copy(HeapRegion* hr) const;
236 double predict_survivor_regions_evac_time() const;
237
238 // Check whether a given young length (young_length) fits into the
239 // given target pause time and whether the prediction for the amount
240 // of objects to be copied for the given length will fit into the
241 // given free space (expressed by base_free_regions). It is used by
242 // calculate_young_list_target_length().
243 bool predict_will_fit(uint young_length, double base_time_ms,
244 uint base_free_regions, double target_pause_time_ms) const;
245
246 public:
247 size_t pending_cards_at_gc_start() const { return _pending_cards_at_gc_start; }
248
249 // Calculate the minimum number of old regions we'll add to the CSet
250 // during a mixed GC.
355 // Set the state to start a concurrent marking cycle and clear
356 // _initiate_conc_mark_if_possible because it has now been
357 // acted on.
358 void initiate_conc_mark();
359
360 public:
361 // This sets the initiate_conc_mark_if_possible() flag to start a
362 // new cycle, as long as we are not already in one. It's best if it
363 // is called during a safepoint when the test whether a cycle is in
364 // progress or not is stable.
365 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
366
367 // This is called at the very beginning of an evacuation pause (it
368 // has to be the first thing that the pause does). If
369 // initiate_conc_mark_if_possible() is true, and the concurrent
370 // marking thread has completed its work during the previous cycle,
371 // it will set in_initial_mark_gc() to so that the pause does
372 // the initial-mark work and start a marking cycle.
373 void decide_on_conc_mark_initiation();
374
375 size_t young_list_target_length() const { return _young_list_target_length; }
376
377 bool should_allocate_mutator_region() const;
378
379 bool can_expand_young_list() const;
380
381 uint young_list_max_length() const {
382 return _young_list_max_length;
383 }
384
385 bool use_adaptive_young_list_length() const;
386
387 void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
388
389 private:
390 //
391 // Survivor regions policy.
392 //
393
394 // Current tenuring threshold, set to 0 if the collector reaches the
414
415 uint tenuring_threshold() const { return _tenuring_threshold; }
416
417 uint max_survivor_regions() {
418 return _max_survivor_regions;
419 }
420
421 void note_start_adding_survivor_regions() {
422 _survivor_surv_rate_group->start_adding_regions();
423 }
424
425 void note_stop_adding_survivor_regions() {
426 _survivor_surv_rate_group->stop_adding_regions();
427 }
428
429 void record_age_table(AgeTable* age_table) {
430 _survivors_age_table.merge(age_table);
431 }
432
433 void print_age_table();
434
435 void update_max_gc_locker_expansion();
436
437 void update_survivors_policy();
438
439 virtual bool force_upgrade_to_full() {
440 return false;
441 }
442 };
443
444 #endif // SHARE_GC_G1_G1POLICY_HPP
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43 // * when to collect.
44
45 class HeapRegion;
46 class G1CollectionSet;
47 class G1CollectionSetCandidates;
48 class G1CollectionSetChooser;
49 class G1IHOPControl;
50 class G1Analytics;
51 class G1SurvivorRegions;
52 class G1YoungGenSizer;
53 class GCPolicyCounters;
54 class STWGCTimer;
55
56 class G1Policy: public CHeapObj<mtGC> {
57 private:
58
59 static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
60 // Update the IHOP control with necessary statistics.
61 void update_ihop_prediction(double mutator_time_s,
62 size_t mutator_alloc_bytes,
63 bool this_gc_was_young_only);
64 void report_ihop_statistics();
65
66 G1Predictions _predictor;
67 G1Analytics* _analytics;
68 G1RemSetTrackingPolicy _remset_tracker;
69 G1MMUTracker* _mmu_tracker;
70 G1IHOPControl* _ihop_control;
71
72 GCPolicyCounters* _policy_counters;
73
74 double _full_collection_start_sec;
75
76 jlong _collection_pause_end_millis;
77
78 uint _young_list_desired_length;
79 uint _young_list_target_length;
80
81 // The max number of regions we can extend the eden by while the GC
82 // locker is active. This should be >= _young_list_target_length;
83 uint _young_list_max_length;
84
85 // The survivor rate groups below must be initialized after the predictor because they
86 // indirectly use it through the "this" object passed to their constructor.
87 G1SurvRateGroup* _eden_surv_rate_group;
88 G1SurvRateGroup* _survivor_surv_rate_group;
89
90 double _reserve_factor;
91 // This will be set when the heap is expanded
92 // for the first time during initialization.
93 uint _reserve_regions;
94
95 G1YoungGenSizer* _young_gen_sizer;
96
97 uint _free_regions_at_end_of_collection;
98
175
176 double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
177 double other_time_ms(double pause_time_ms) const;
178
179 double young_other_time_ms() const;
180 double non_young_other_time_ms() const;
181 double constant_other_time_ms(double pause_time_ms) const;
182
183 G1CollectionSetChooser* cset_chooser() const;
184
185 // Stash a pointer to the g1 heap.
186 G1CollectedHeap* _g1h;
187
188 G1GCPhaseTimes* _phase_times;
189
190 // This set of variables tracks the collector efficiency, in order to
191 // determine whether we should initiate a new marking.
192 double _mark_remark_start_sec;
193 double _mark_cleanup_start_sec;
194
195 // Updates the internal young gen maximum and target and desired lengths.
196 // If no rs_length parameter is passed, predict the RS length using the
197 // prediction model, otherwise use the given rs_length as the prediction.
198 void update_young_length_bounds();
199 void update_young_length_bounds(size_t rs_length);
200
201 // Calculate and return the minimum desired eden length based on the MMU target.
202 uint calculate_desired_eden_length_by_mmu() const;
203
204 // Calculate and return the desired eden length that can fit into the pause time goal.
205 // The parameters are: rs_length represents the prediction of how large the
206 // young RSet lengths will be, min_eden_length and max_eden_length are the bounds
207 // (inclusive) within eden can grow.
208 uint calculate_desired_eden_length_by_pause(double base_time_ms,
209 uint min_eden_length,
210 uint max_eden_length) const;
211
212 // Calculates the desired eden length before mixed gc so that after adding the
213 // minimum amount of old gen regions from the collection set, the eden fits into
214 // the pause time goal.
215 uint calculate_desired_eden_length_before_mixed(double survivor_base_time_ms,
216 uint min_eden_length,
217 uint max_eden_length) const;
218
219 // Calculate desired young length based on current situation without taking actually
220 // available free regions into account.
221 uint calculate_young_desired_length(size_t rs_length) const;
222 // Limit the given desired young length to available free regions.
223 uint calculate_young_target_length(uint desired_young_length) const;
224 // The GCLocker might cause us to need more regions than the target. Calculate
225 // the maximum number of regions to use in that case.
226 uint calculate_young_max_length(uint target_young_length) const;
227
228 void update_rs_length_prediction();
229 void update_rs_length_prediction(size_t prediction);
230
231 size_t predict_bytes_to_copy(HeapRegion* hr) const;
232 double predict_survivor_regions_evac_time() const;
233
234 // Check whether a given young length (young_length) fits into the
235 // given target pause time and whether the prediction for the amount
236 // of objects to be copied for the given length will fit into the
237 // given free space (expressed by base_free_regions). It is used by
238 // calculate_young_list_target_length().
239 bool predict_will_fit(uint young_length, double base_time_ms,
240 uint base_free_regions, double target_pause_time_ms) const;
241
242 public:
243 size_t pending_cards_at_gc_start() const { return _pending_cards_at_gc_start; }
244
245 // Calculate the minimum number of old regions we'll add to the CSet
246 // during a mixed GC.
351 // Set the state to start a concurrent marking cycle and clear
352 // _initiate_conc_mark_if_possible because it has now been
353 // acted on.
354 void initiate_conc_mark();
355
356 public:
357 // This sets the initiate_conc_mark_if_possible() flag to start a
358 // new cycle, as long as we are not already in one. It's best if it
359 // is called during a safepoint when the test whether a cycle is in
360 // progress or not is stable.
361 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
362
363 // This is called at the very beginning of an evacuation pause (it
364 // has to be the first thing that the pause does). If
365 // initiate_conc_mark_if_possible() is true, and the concurrent
366 // marking thread has completed its work during the previous cycle,
367 // it will set in_initial_mark_gc() to so that the pause does
368 // the initial-mark work and start a marking cycle.
369 void decide_on_conc_mark_initiation();
370
371 uint young_list_desired_length() const { return _young_list_desired_length; }
372 size_t young_list_target_length() const { return _young_list_target_length; }
373
374 bool should_allocate_mutator_region() const;
375
376 bool can_expand_young_list() const;
377
378 uint young_list_max_length() const {
379 return _young_list_max_length;
380 }
381
382 bool use_adaptive_young_list_length() const;
383
384 void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
385
386 private:
387 //
388 // Survivor regions policy.
389 //
390
391 // Current tenuring threshold, set to 0 if the collector reaches the
411
412 uint tenuring_threshold() const { return _tenuring_threshold; }
413
414 uint max_survivor_regions() {
415 return _max_survivor_regions;
416 }
417
418 void note_start_adding_survivor_regions() {
419 _survivor_surv_rate_group->start_adding_regions();
420 }
421
422 void note_stop_adding_survivor_regions() {
423 _survivor_surv_rate_group->stop_adding_regions();
424 }
425
426 void record_age_table(AgeTable* age_table) {
427 _survivors_age_table.merge(age_table);
428 }
429
430 void print_age_table();
431
432 void update_survivors_policy();
433
434 virtual bool force_upgrade_to_full() {
435 return false;
436 }
437 };
438
439 #endif // SHARE_GC_G1_G1POLICY_HPP
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