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src/hotspot/share/gc/g1/g1Policy.hpp

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rev 59792 : imported patch 8244603-sjohanss-review


  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   uint _young_list_fixed_length;
  81 
  82   // The max number of regions we can extend the eden by while the GC
  83   // locker is active. This should be >= _young_list_target_length;
  84   uint _young_list_max_length;
  85 
  86   // The survivor rate groups below must be initialized after the predictor because they
  87   // indirectly use it through the "this" object passed to their constructor.
  88   G1SurvRateGroup* _eden_surv_rate_group;
  89   G1SurvRateGroup* _survivor_surv_rate_group;
  90 
  91   double _reserve_factor;
  92   // This will be set when the heap is expanded
  93   // for the first time during initialization.
  94   uint   _reserve_regions;
  95 
  96   G1YoungGenSizer* _young_gen_sizer;
  97 
  98   uint _free_regions_at_end_of_collection;
  99 
 100   size_t _rs_length;


 153     bool update = should_update_surv_rate_group_predictors();
 154 
 155     _eden_surv_rate_group->all_surviving_words_recorded(predictor(), update);
 156     _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update);
 157   }
 158 
 159   G1MMUTracker* mmu_tracker() {
 160     return _mmu_tracker;
 161   }
 162 
 163   const G1MMUTracker* mmu_tracker() const {
 164     return _mmu_tracker;
 165   }
 166 
 167   double max_pause_time_ms() const {
 168     return _mmu_tracker->max_gc_time() * 1000.0;
 169   }
 170 
 171 private:
 172   G1CollectionSet* _collection_set;




 173   double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
 174   double other_time_ms(double pause_time_ms) const;
 175 
 176   double young_other_time_ms() const;
 177   double non_young_other_time_ms() const;
 178   double constant_other_time_ms(double pause_time_ms) const;
 179 
 180   G1CollectionSetChooser* cset_chooser() const;
 181 
 182   // Stash a pointer to the g1 heap.
 183   G1CollectedHeap* _g1h;
 184 
 185   G1GCPhaseTimes* _phase_times;
 186 
 187   // This set of variables tracks the collector efficiency, in order to
 188   // determine whether we should initiate a new marking.
 189   double _mark_remark_start_sec;
 190   double _mark_cleanup_start_sec;
 191 
 192   // Updates the internal young list maximum and target lengths. Returns the
 193   // unbounded young list target length. If no rs_length parameter is passed,
 194   // predict the RS length using the prediction model, otherwise use the
 195   // given rs_length as the prediction.
 196   uint update_young_list_max_and_target_length();
 197   uint update_young_list_max_and_target_length(size_t rs_length);
 198 
 199   // Update the young list target length either by setting it to the
 200   // desired fixed value or by calculating it using G1's pause
 201   // prediction model.
 202   // Returns the unbounded young list target length.
 203   uint update_young_list_target_length(size_t rs_length);
 204 
 205   // Calculate and return the minimum desired young list target
 206   // length. This is the minimum desired young list length according
 207   // to the user's inputs.
 208   uint calculate_young_list_desired_min_length(uint base_min_length) const;
 209 
 210   // Calculate and return the maximum desired young list target
 211   // length. This is the maximum desired young list length according
 212   // to the user's inputs.
 213   uint calculate_young_list_desired_max_length() const;
 214 
 215   // Calculate and return the maximum young list target length that
 216   // can fit into the pause time goal. The parameters are: rs_length
 217   // represent the prediction of how large the young RSet lengths will
 218   // be, base_min_length is the already existing number of regions in
 219   // the young list, min_length and max_length are the desired min and
 220   // max young list length according to the user's inputs.
 221   uint calculate_young_list_target_length(size_t rs_length,
 222                                           uint base_min_length,
 223                                           uint desired_min_length,
 224                                           uint desired_max_length) const;
 225 
 226   // Result of the bounded_young_list_target_length() method, containing both the
 227   // bounded as well as the unbounded young list target lengths in this order.
 228   typedef Pair<uint, uint, StackObj> YoungTargetLengths;
 229   YoungTargetLengths young_list_target_lengths(size_t rs_length) const;
 230 
 231   void update_rs_length_prediction();
 232   void update_rs_length_prediction(size_t prediction);
 233 
 234   size_t predict_bytes_to_copy(HeapRegion* hr) const;
 235   double predict_survivor_regions_evac_time() const;
 236 
 237   // Check whether a given young length (young_length) fits into the
 238   // given target pause time and whether the prediction for the amount
 239   // of objects to be copied for the given length will fit into the
 240   // given free space (expressed by base_free_regions).  It is used by
 241   // calculate_young_list_target_length().
 242   bool predict_will_fit(uint young_length, double base_time_ms,
 243                         uint base_free_regions, double target_pause_time_ms) const;
 244 
 245 public:
 246   size_t pending_cards_at_gc_start() const { return _pending_cards_at_gc_start; }
 247 
 248   // Calculate the minimum number of old regions we'll add to the CSet
 249   // during a mixed GC.


 318   void record_collection_pause_start(double start_time_sec);
 319   virtual void record_collection_pause_end(double pause_time_ms);
 320 
 321   // Record the start and end of a full collection.
 322   void record_full_collection_start();
 323   virtual void record_full_collection_end();
 324 
 325   // Must currently be called while the world is stopped.
 326   void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
 327 
 328   // Record start and end of remark.
 329   void record_concurrent_mark_remark_start();
 330   void record_concurrent_mark_remark_end();
 331 
 332   // Record start, end, and completion of cleanup.
 333   void record_concurrent_mark_cleanup_start();
 334   void record_concurrent_mark_cleanup_end();
 335 
 336   void print_phases();
 337 
 338   bool next_gc_should_be_mixed(const char* true_action_str,
 339                                const char* false_action_str) const;
 340 
 341   // Calculate and return the number of initial and optional old gen regions from
 342   // the given collection set candidates and the remaining time.
 343   void calculate_old_collection_set_regions(G1CollectionSetCandidates* candidates,
 344                                             double time_remaining_ms,
 345                                             uint& num_initial_regions,
 346                                             uint& num_optional_regions);
 347 
 348   // Calculate the number of optional regions from the given collection set candidates,
 349   // the remaining time and the maximum number of these regions and return the number
 350   // of actually selected regions in num_optional_regions.
 351   void calculate_optional_collection_set_regions(G1CollectionSetCandidates* candidates,
 352                                                  uint const max_optional_regions,
 353                                                  double time_remaining_ms,
 354                                                  uint& num_optional_regions);
 355 
 356 private:
 357   // Set the state to start a concurrent marking cycle and clear
 358   // _initiate_conc_mark_if_possible because it has now been
 359   // acted on.
 360   void initiate_conc_mark();
 361 
 362 public:
 363   // This sets the initiate_conc_mark_if_possible() flag to start a
 364   // new cycle, as long as we are not already in one. It's best if it
 365   // is called during a safepoint when the test whether a cycle is in
 366   // progress or not is stable.
 367   bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
 368 
 369   // This is called at the very beginning of an evacuation pause (it
 370   // has to be the first thing that the pause does). If
 371   // initiate_conc_mark_if_possible() is true, and the concurrent
 372   // marking thread has completed its work during the previous cycle,
 373   // it will set in_initial_mark_gc() to so that the pause does
 374   // the initial-mark work and start a marking cycle.
 375   void decide_on_conc_mark_initiation();
 376 

 377   size_t young_list_target_length() const { return _young_list_target_length; }
 378 
 379   bool should_allocate_mutator_region() const;
 380 
 381   bool can_expand_young_list() const;
 382 
 383   uint young_list_max_length() const {
 384     return _young_list_max_length;
 385   }
 386 
 387   bool use_adaptive_young_list_length() const;
 388 
 389   void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
 390 
 391 private:
 392   //
 393   // Survivor regions policy.
 394   //
 395 
 396   // Current tenuring threshold, set to 0 if the collector reaches the


 416 
 417   uint tenuring_threshold() const { return _tenuring_threshold; }
 418 
 419   uint max_survivor_regions() {
 420     return _max_survivor_regions;
 421   }
 422 
 423   void note_start_adding_survivor_regions() {
 424     _survivor_surv_rate_group->start_adding_regions();
 425   }
 426 
 427   void note_stop_adding_survivor_regions() {
 428     _survivor_surv_rate_group->stop_adding_regions();
 429   }
 430 
 431   void record_age_table(AgeTable* age_table) {
 432     _survivors_age_table.merge(age_table);
 433   }
 434 
 435   void print_age_table();
 436 
 437   void update_max_gc_locker_expansion();
 438 
 439   void update_survivors_policy();
 440 
 441   virtual bool force_upgrade_to_full() {
 442     return false;
 443   }
 444 };
 445 
 446 #endif // SHARE_GC_G1_G1POLICY_HPP


  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 
  99   size_t _rs_length;


 152     bool update = should_update_surv_rate_group_predictors();
 153 
 154     _eden_surv_rate_group->all_surviving_words_recorded(predictor(), update);
 155     _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update);
 156   }
 157 
 158   G1MMUTracker* mmu_tracker() {
 159     return _mmu_tracker;
 160   }
 161 
 162   const G1MMUTracker* mmu_tracker() const {
 163     return _mmu_tracker;
 164   }
 165 
 166   double max_pause_time_ms() const {
 167     return _mmu_tracker->max_gc_time() * 1000.0;
 168   }
 169 
 170 private:
 171   G1CollectionSet* _collection_set;
 172 
 173   bool next_gc_should_be_mixed(const char* true_action_str,
 174                                const char* false_action_str) const;
 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.


 315   void record_collection_pause_start(double start_time_sec);
 316   virtual void record_collection_pause_end(double pause_time_ms);
 317 
 318   // Record the start and end of a full collection.
 319   void record_full_collection_start();
 320   virtual void record_full_collection_end();
 321 
 322   // Must currently be called while the world is stopped.
 323   void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
 324 
 325   // Record start and end of remark.
 326   void record_concurrent_mark_remark_start();
 327   void record_concurrent_mark_remark_end();
 328 
 329   // Record start, end, and completion of cleanup.
 330   void record_concurrent_mark_cleanup_start();
 331   void record_concurrent_mark_cleanup_end();
 332 
 333   void print_phases();
 334 



 335   // Calculate and return the number of initial and optional old gen regions from
 336   // the given collection set candidates and the remaining time.
 337   void calculate_old_collection_set_regions(G1CollectionSetCandidates* candidates,
 338                                             double time_remaining_ms,
 339                                             uint& num_initial_regions,
 340                                             uint& num_optional_regions);
 341 
 342   // Calculate the number of optional regions from the given collection set candidates,
 343   // the remaining time and the maximum number of these regions and return the number
 344   // of actually selected regions in num_optional_regions.
 345   void calculate_optional_collection_set_regions(G1CollectionSetCandidates* candidates,
 346                                                  uint const max_optional_regions,
 347                                                  double time_remaining_ms,
 348                                                  uint& num_optional_regions);
 349 
 350 private:
 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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