rev 9277 : imported patch 8140597-forcing-initial-mark-causes-abort-mixed-collections

   1 /*
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  24 
  25 #ifndef SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP
  26 #define SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP
  27 
  28 #include "gc/g1/collectionSetChooser.hpp"
  29 #include "gc/g1/g1CollectorState.hpp"
  30 #include "gc/g1/g1GCPhaseTimes.hpp"
  31 #include "gc/g1/g1InCSetState.hpp"
  32 #include "gc/g1/g1MMUTracker.hpp"
  33 #include "gc/g1/g1Predictions.hpp"
  34 #include "gc/shared/collectorPolicy.hpp"
  35 
  36 // A G1CollectorPolicy makes policy decisions that determine the
  37 // characteristics of the collector.  Examples include:
  38 //   * choice of collection set.
  39 //   * when to collect.
  40 
  41 class HeapRegion;
  42 class CollectionSetChooser;
  43 
  44 // TraceYoungGenTime collects data on _both_ young and mixed evacuation pauses
  45 // (the latter may contain non-young regions - i.e. regions that are
  46 // technically in old) while TraceOldGenTime collects data about full GCs.
  47 class TraceYoungGenTimeData : public CHeapObj<mtGC> {
  48  private:
  49   unsigned  _young_pause_num;
  50   unsigned  _mixed_pause_num;
  51 
  52   NumberSeq _all_stop_world_times_ms;
  53   NumberSeq _all_yield_times_ms;
  54 
  55   NumberSeq _total;
  56   NumberSeq _other;
  57   NumberSeq _root_region_scan_wait;
  58   NumberSeq _parallel;
  59   NumberSeq _ext_root_scan;
  60   NumberSeq _satb_filtering;
  61   NumberSeq _update_rs;
  62   NumberSeq _scan_rs;
  63   NumberSeq _obj_copy;
  64   NumberSeq _termination;
  65   NumberSeq _parallel_other;
  66   NumberSeq _clear_ct;
  67 
  68   void print_summary(const char* str, const NumberSeq* seq) const;
  69   void print_summary_sd(const char* str, const NumberSeq* seq) const;
  70 
  71 public:
  72    TraceYoungGenTimeData() : _young_pause_num(0), _mixed_pause_num(0) {};
  73   void record_start_collection(double time_to_stop_the_world_ms);
  74   void record_yield_time(double yield_time_ms);
  75   void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times);
  76   void increment_young_collection_count();
  77   void increment_mixed_collection_count();
  78   void print() const;
  79 };
  80 
  81 class TraceOldGenTimeData : public CHeapObj<mtGC> {
  82  private:
  83   NumberSeq _all_full_gc_times;
  84 
  85  public:
  86   void record_full_collection(double full_gc_time_ms);
  87   void print() const;
  88 };
  89 
  90 // There are three command line options related to the young gen size:
  91 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
  92 // just a short form for NewSize==MaxNewSize). G1 will use its internal
  93 // heuristics to calculate the actual young gen size, so these options
  94 // basically only limit the range within which G1 can pick a young gen
  95 // size. Also, these are general options taking byte sizes. G1 will
  96 // internally work with a number of regions instead. So, some rounding
  97 // will occur.
  98 //
  99 // If nothing related to the the young gen size is set on the command
 100 // line we should allow the young gen to be between G1NewSizePercent
 101 // and G1MaxNewSizePercent of the heap size. This means that every time
 102 // the heap size changes, the limits for the young gen size will be
 103 // recalculated.
 104 //
 105 // If only -XX:NewSize is set we should use the specified value as the
 106 // minimum size for young gen. Still using G1MaxNewSizePercent of the
 107 // heap as maximum.
 108 //
 109 // If only -XX:MaxNewSize is set we should use the specified value as the
 110 // maximum size for young gen. Still using G1NewSizePercent of the heap
 111 // as minimum.
 112 //
 113 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
 114 // No updates when the heap size changes. There is a special case when
 115 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
 116 // different heuristic for calculating the collection set when we do mixed
 117 // collection.
 118 //
 119 // If only -XX:NewRatio is set we should use the specified ratio of the heap
 120 // as both min and max. This will be interpreted as "fixed" just like the
 121 // NewSize==MaxNewSize case above. But we will update the min and max
 122 // every time the heap size changes.
 123 //
 124 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
 125 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
 126 class G1YoungGenSizer : public CHeapObj<mtGC> {
 127 private:
 128   enum SizerKind {
 129     SizerDefaults,
 130     SizerNewSizeOnly,
 131     SizerMaxNewSizeOnly,
 132     SizerMaxAndNewSize,
 133     SizerNewRatio
 134   };
 135   SizerKind _sizer_kind;
 136   uint _min_desired_young_length;
 137   uint _max_desired_young_length;
 138   bool _adaptive_size;
 139   uint calculate_default_min_length(uint new_number_of_heap_regions);
 140   uint calculate_default_max_length(uint new_number_of_heap_regions);
 141 
 142   // Update the given values for minimum and maximum young gen length in regions
 143   // given the number of heap regions depending on the kind of sizing algorithm.
 144   void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length);
 145 
 146 public:
 147   G1YoungGenSizer();
 148   // Calculate the maximum length of the young gen given the number of regions
 149   // depending on the sizing algorithm.
 150   uint max_young_length(uint number_of_heap_regions);
 151 
 152   void heap_size_changed(uint new_number_of_heap_regions);
 153   uint min_desired_young_length() {
 154     return _min_desired_young_length;
 155   }
 156   uint max_desired_young_length() {
 157     return _max_desired_young_length;
 158   }
 159   bool adaptive_young_list_length() const {
 160     return _adaptive_size;
 161   }
 162 };
 163 
 164 class G1CollectorPolicy: public CollectorPolicy {
 165  private:
 166   G1Predictions _predictor;
 167 
 168   double get_new_prediction(TruncatedSeq const* seq) const;
 169 
 170   // either equal to the number of parallel threads, if ParallelGCThreads
 171   // has been set, or 1 otherwise
 172   int _parallel_gc_threads;
 173 
 174   // The number of GC threads currently active.
 175   uintx _no_of_gc_threads;
 176 
 177   G1MMUTracker* _mmu_tracker;
 178 
 179   void initialize_alignments();
 180   void initialize_flags();
 181 
 182   CollectionSetChooser* _collectionSetChooser;
 183 
 184   double _full_collection_start_sec;
 185   uint   _cur_collection_pause_used_regions_at_start;
 186 
 187   // These exclude marking times.
 188   TruncatedSeq* _recent_gc_times_ms;
 189 
 190   TruncatedSeq* _concurrent_mark_remark_times_ms;
 191   TruncatedSeq* _concurrent_mark_cleanup_times_ms;
 192 
 193   TraceYoungGenTimeData _trace_young_gen_time_data;
 194   TraceOldGenTimeData   _trace_old_gen_time_data;
 195 
 196   double _stop_world_start;
 197 
 198   uint _young_list_target_length;
 199   uint _young_list_fixed_length;
 200 
 201   // The max number of regions we can extend the eden by while the GC
 202   // locker is active. This should be >= _young_list_target_length;
 203   uint _young_list_max_length;
 204 
 205   SurvRateGroup* _short_lived_surv_rate_group;
 206   SurvRateGroup* _survivor_surv_rate_group;
 207   // add here any more surv rate groups
 208 
 209   double _gc_overhead_perc;
 210 
 211   double _reserve_factor;
 212   uint   _reserve_regions;
 213 
 214   enum PredictionConstants {
 215     TruncatedSeqLength = 10,
 216     NumPrevPausesForHeuristics = 10
 217   };
 218 
 219   TruncatedSeq* _alloc_rate_ms_seq;
 220   double        _prev_collection_pause_end_ms;
 221 
 222   TruncatedSeq* _rs_length_diff_seq;
 223   TruncatedSeq* _cost_per_card_ms_seq;
 224   TruncatedSeq* _cost_scan_hcc_seq;
 225   TruncatedSeq* _young_cards_per_entry_ratio_seq;
 226   TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
 227   TruncatedSeq* _cost_per_entry_ms_seq;
 228   TruncatedSeq* _mixed_cost_per_entry_ms_seq;
 229   TruncatedSeq* _cost_per_byte_ms_seq;
 230   TruncatedSeq* _constant_other_time_ms_seq;
 231   TruncatedSeq* _young_other_cost_per_region_ms_seq;
 232   TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
 233 
 234   TruncatedSeq* _pending_cards_seq;
 235   TruncatedSeq* _rs_lengths_seq;
 236 
 237   TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
 238 
 239   G1YoungGenSizer* _young_gen_sizer;
 240 
 241   uint _eden_cset_region_length;
 242   uint _survivor_cset_region_length;
 243   uint _old_cset_region_length;
 244 
 245   void init_cset_region_lengths(uint eden_cset_region_length,
 246                                 uint survivor_cset_region_length);
 247 
 248   uint eden_cset_region_length() const     { return _eden_cset_region_length;     }
 249   uint survivor_cset_region_length() const { return _survivor_cset_region_length; }
 250   uint old_cset_region_length() const      { return _old_cset_region_length;      }
 251 
 252   uint _free_regions_at_end_of_collection;
 253 
 254   size_t _recorded_rs_lengths;
 255   size_t _max_rs_lengths;
 256 
 257   size_t _rs_lengths_prediction;
 258 
 259 #ifndef PRODUCT
 260   bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
 261 #endif // PRODUCT
 262 
 263   void adjust_concurrent_refinement(double update_rs_time,
 264                                     double update_rs_processed_buffers,
 265                                     double goal_ms);
 266 
 267   uintx no_of_gc_threads() { return _no_of_gc_threads; }
 268   void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
 269 
 270   double _pause_time_target_ms;
 271 
 272   size_t _pending_cards;
 273 
 274 public:
 275   G1Predictions& predictor() { return _predictor; }
 276 
 277   // Accessors
 278 
 279   void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
 280     hr->set_eden();
 281     hr->install_surv_rate_group(_short_lived_surv_rate_group);
 282     hr->set_young_index_in_cset(young_index_in_cset);
 283   }
 284 
 285   void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
 286     assert(hr->is_survivor(), "pre-condition");
 287     hr->install_surv_rate_group(_survivor_surv_rate_group);
 288     hr->set_young_index_in_cset(young_index_in_cset);
 289   }
 290 
 291 #ifndef PRODUCT
 292   bool verify_young_ages();
 293 #endif // PRODUCT
 294 
 295   void record_max_rs_lengths(size_t rs_lengths) {
 296     _max_rs_lengths = rs_lengths;
 297   }
 298 
 299   size_t predict_rs_length_diff() const;
 300 
 301   double predict_alloc_rate_ms() const;
 302 
 303   double predict_cost_per_card_ms() const;
 304 
 305   double predict_scan_hcc_ms() const;
 306 
 307   double predict_rs_update_time_ms(size_t pending_cards) const;
 308 
 309   double predict_young_cards_per_entry_ratio() const;
 310 
 311   double predict_mixed_cards_per_entry_ratio() const;
 312 
 313   size_t predict_young_card_num(size_t rs_length) const;
 314 
 315   size_t predict_non_young_card_num(size_t rs_length) const;
 316 
 317   double predict_rs_scan_time_ms(size_t card_num) const;
 318 
 319   double predict_mixed_rs_scan_time_ms(size_t card_num) const;
 320 
 321   double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
 322 
 323   double predict_object_copy_time_ms(size_t bytes_to_copy) const;
 324 
 325   double predict_constant_other_time_ms() const;
 326 
 327   double predict_young_other_time_ms(size_t young_num) const;
 328 
 329   double predict_non_young_other_time_ms(size_t non_young_num) const;
 330 
 331   double predict_base_elapsed_time_ms(size_t pending_cards) const;
 332   double predict_base_elapsed_time_ms(size_t pending_cards,
 333                                       size_t scanned_cards) const;
 334   size_t predict_bytes_to_copy(HeapRegion* hr) const;
 335   double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
 336 
 337   void set_recorded_rs_lengths(size_t rs_lengths);
 338 
 339   uint cset_region_length() const       { return young_cset_region_length() +
 340                                            old_cset_region_length(); }
 341   uint young_cset_region_length() const { return eden_cset_region_length() +
 342                                            survivor_cset_region_length(); }
 343 
 344   double predict_survivor_regions_evac_time() const;
 345 
 346   bool should_update_surv_rate_group_predictors() {
 347     return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
 348   }
 349 
 350   void cset_regions_freed() {
 351     bool update = should_update_surv_rate_group_predictors();
 352 
 353     _short_lived_surv_rate_group->all_surviving_words_recorded(update);
 354     _survivor_surv_rate_group->all_surviving_words_recorded(update);
 355   }
 356 
 357   G1MMUTracker* mmu_tracker() {
 358     return _mmu_tracker;
 359   }
 360 
 361   const G1MMUTracker* mmu_tracker() const {
 362     return _mmu_tracker;
 363   }
 364 
 365   double max_pause_time_ms() const {
 366     return _mmu_tracker->max_gc_time() * 1000.0;
 367   }
 368 
 369   double predict_remark_time_ms() const;
 370 
 371   double predict_cleanup_time_ms() const;
 372 
 373   // Returns an estimate of the survival rate of the region at yg-age
 374   // "yg_age".
 375   double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
 376 
 377   double predict_yg_surv_rate(int age) const;
 378 
 379   double accum_yg_surv_rate_pred(int age) const;
 380 
 381 protected:
 382   virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
 383   virtual double other_time_ms(double pause_time_ms) const;
 384 
 385   double young_other_time_ms() const;
 386   double non_young_other_time_ms() const;
 387   double constant_other_time_ms(double pause_time_ms) const;
 388 
 389 private:
 390   // Statistics kept per GC stoppage, pause or full.
 391   TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
 392 
 393   // Add a new GC of the given duration and end time to the record.
 394   void update_recent_gc_times(double end_time_sec, double elapsed_ms);
 395 
 396   // The head of the list (via "next_in_collection_set()") representing the
 397   // current collection set. Set from the incrementally built collection
 398   // set at the start of the pause.
 399   HeapRegion* _collection_set;
 400 
 401   // The number of bytes in the collection set before the pause. Set from
 402   // the incrementally built collection set at the start of an evacuation
 403   // pause, and incremented in finalize_old_cset_part() when adding old regions
 404   // (if any) to the collection set.
 405   size_t _collection_set_bytes_used_before;
 406 
 407   // The number of bytes copied during the GC.
 408   size_t _bytes_copied_during_gc;
 409 
 410   // The associated information that is maintained while the incremental
 411   // collection set is being built with young regions. Used to populate
 412   // the recorded info for the evacuation pause.
 413 
 414   enum CSetBuildType {
 415     Active,             // We are actively building the collection set
 416     Inactive            // We are not actively building the collection set
 417   };
 418 
 419   CSetBuildType _inc_cset_build_state;
 420 
 421   // The head of the incrementally built collection set.
 422   HeapRegion* _inc_cset_head;
 423 
 424   // The tail of the incrementally built collection set.
 425   HeapRegion* _inc_cset_tail;
 426 
 427   // The number of bytes in the incrementally built collection set.
 428   // Used to set _collection_set_bytes_used_before at the start of
 429   // an evacuation pause.
 430   size_t _inc_cset_bytes_used_before;
 431 
 432   // Used to record the highest end of heap region in collection set
 433   HeapWord* _inc_cset_max_finger;
 434 
 435   // The RSet lengths recorded for regions in the CSet. It is updated
 436   // by the thread that adds a new region to the CSet. We assume that
 437   // only one thread can be allocating a new CSet region (currently,
 438   // it does so after taking the Heap_lock) hence no need to
 439   // synchronize updates to this field.
 440   size_t _inc_cset_recorded_rs_lengths;
 441 
 442   // A concurrent refinement thread periodically samples the young
 443   // region RSets and needs to update _inc_cset_recorded_rs_lengths as
 444   // the RSets grow. Instead of having to synchronize updates to that
 445   // field we accumulate them in this field and add it to
 446   // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
 447   ssize_t _inc_cset_recorded_rs_lengths_diffs;
 448 
 449   // The predicted elapsed time it will take to collect the regions in
 450   // the CSet. This is updated by the thread that adds a new region to
 451   // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
 452   // MT-safety assumptions.
 453   double _inc_cset_predicted_elapsed_time_ms;
 454 
 455   // See the comment for _inc_cset_recorded_rs_lengths_diffs.
 456   double _inc_cset_predicted_elapsed_time_ms_diffs;
 457 
 458   // Stash a pointer to the g1 heap.
 459   G1CollectedHeap* _g1;
 460 
 461   G1GCPhaseTimes* _phase_times;
 462 
 463   // The ratio of gc time to elapsed time, computed over recent pauses.
 464   double _recent_avg_pause_time_ratio;
 465 
 466   double recent_avg_pause_time_ratio() const {
 467     return _recent_avg_pause_time_ratio;
 468   }
 469 
 470   // This set of variables tracks the collector efficiency, in order to
 471   // determine whether we should initiate a new marking.
 472   double _cur_mark_stop_world_time_ms;
 473   double _mark_remark_start_sec;
 474   double _mark_cleanup_start_sec;
 475 
 476   void update_young_list_max_and_target_length();
 477   void update_young_list_max_and_target_length(size_t rs_lengths);
 478 
 479   // Update the young list target length either by setting it to the
 480   // desired fixed value or by calculating it using G1's pause
 481   // prediction model. If no rs_lengths parameter is passed, predict
 482   // the RS lengths using the prediction model, otherwise use the
 483   // given rs_lengths as the prediction.
 484   void update_young_list_target_length();
 485   void update_young_list_target_length(size_t rs_lengths);
 486 
 487   // Calculate and return the minimum desired young list target
 488   // length. This is the minimum desired young list length according
 489   // to the user's inputs.
 490   uint calculate_young_list_desired_min_length(uint base_min_length) const;
 491 
 492   // Calculate and return the maximum desired young list target
 493   // length. This is the maximum desired young list length according
 494   // to the user's inputs.
 495   uint calculate_young_list_desired_max_length() const;
 496 
 497   // Calculate and return the maximum young list target length that
 498   // can fit into the pause time goal. The parameters are: rs_lengths
 499   // represent the prediction of how large the young RSet lengths will
 500   // be, base_min_length is the already existing number of regions in
 501   // the young list, min_length and max_length are the desired min and
 502   // max young list length according to the user's inputs.
 503   uint calculate_young_list_target_length(size_t rs_lengths,
 504                                           uint base_min_length,
 505                                           uint desired_min_length,
 506                                           uint desired_max_length) const;
 507 
 508   uint bounded_young_list_target_length(size_t rs_lengths) const;
 509 
 510   void update_rs_lengths_prediction();
 511   void update_rs_lengths_prediction(size_t prediction);
 512 
 513   // Calculate and return chunk size (in number of regions) for parallel
 514   // concurrent mark cleanup.
 515   uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const;
 516 
 517   // Check whether a given young length (young_length) fits into the
 518   // given target pause time and whether the prediction for the amount
 519   // of objects to be copied for the given length will fit into the
 520   // given free space (expressed by base_free_regions).  It is used by
 521   // calculate_young_list_target_length().
 522   bool predict_will_fit(uint young_length, double base_time_ms,
 523                         uint base_free_regions, double target_pause_time_ms) const;
 524 
 525   // Calculate the minimum number of old regions we'll add to the CSet
 526   // during a mixed GC.
 527   uint calc_min_old_cset_length() const;
 528 
 529   // Calculate the maximum number of old regions we'll add to the CSet
 530   // during a mixed GC.
 531   uint calc_max_old_cset_length() const;
 532 
 533   // Returns the given amount of uncollected reclaimable space
 534   // as a percentage of the current heap capacity.
 535   double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
 536 
 537 public:
 538 
 539   G1CollectorPolicy();
 540 
 541   virtual G1CollectorPolicy* as_g1_policy() { return this; }
 542 
 543   G1CollectorState* collector_state() const;
 544 
 545   G1GCPhaseTimes* phase_times() const { return _phase_times; }
 546 
 547   // Check the current value of the young list RSet lengths and
 548   // compare it against the last prediction. If the current value is
 549   // higher, recalculate the young list target length prediction.
 550   void revise_young_list_target_length_if_necessary();
 551 
 552   // This should be called after the heap is resized.
 553   void record_new_heap_size(uint new_number_of_regions);
 554 
 555   void init();
 556 
 557   virtual void note_gc_start(uint num_active_workers);
 558 
 559   // Create jstat counters for the policy.
 560   virtual void initialize_gc_policy_counters();
 561 
 562   virtual HeapWord* mem_allocate_work(size_t size,
 563                                       bool is_tlab,
 564                                       bool* gc_overhead_limit_was_exceeded);
 565 
 566   // This method controls how a collector handles one or more
 567   // of its generations being fully allocated.
 568   virtual HeapWord* satisfy_failed_allocation(size_t size,
 569                                               bool is_tlab);
 570 
 571   bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
 572 
 573   bool about_to_start_mixed_phase() const;
 574 
 575   // Record the start and end of an evacuation pause.
 576   void record_collection_pause_start(double start_time_sec);
 577   void record_collection_pause_end(double pause_time_ms, size_t cards_scanned);
 578 
 579   // Record the start and end of a full collection.
 580   void record_full_collection_start();
 581   void record_full_collection_end();
 582 
 583   // Must currently be called while the world is stopped.
 584   void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
 585 
 586   // Record start and end of remark.
 587   void record_concurrent_mark_remark_start();
 588   void record_concurrent_mark_remark_end();
 589 
 590   // Record start, end, and completion of cleanup.
 591   void record_concurrent_mark_cleanup_start();
 592   void record_concurrent_mark_cleanup_end();
 593   void record_concurrent_mark_cleanup_completed();
 594 
 595   // Records the information about the heap size for reporting in
 596   // print_detailed_heap_transition
 597   void record_heap_size_info_at_start(bool full);
 598 
 599   // Print heap sizing transition (with less and more detail).
 600 
 601   void print_heap_transition(size_t bytes_before) const;
 602   void print_heap_transition() const;
 603   void print_detailed_heap_transition(bool full = false) const;
 604 
 605   virtual void print_phases(double pause_time_sec);
 606 
 607   void record_stop_world_start();
 608   void record_concurrent_pause();
 609 
 610   // Record how much space we copied during a GC. This is typically
 611   // called when a GC alloc region is being retired.
 612   void record_bytes_copied_during_gc(size_t bytes) {
 613     _bytes_copied_during_gc += bytes;
 614   }
 615 
 616   // The amount of space we copied during a GC.
 617   size_t bytes_copied_during_gc() const {
 618     return _bytes_copied_during_gc;
 619   }
 620 
 621   size_t collection_set_bytes_used_before() const {
 622     return _collection_set_bytes_used_before;
 623   }
 624 
 625   // Determine whether there are candidate regions so that the
 626   // next GC should be mixed. The two action strings are used
 627   // in the ergo output when the method returns true or false.
 628   bool next_gc_should_be_mixed(const char* true_action_str,
 629                                const char* false_action_str) const;
 630 
 631   // Choose a new collection set.  Marks the chosen regions as being
 632   // "in_collection_set", and links them together.  The head and number of
 633   // the collection set are available via access methods.
 634   double finalize_young_cset_part(double target_pause_time_ms);
 635   virtual void finalize_old_cset_part(double time_remaining_ms);
 636 
 637   // The head of the list (via "next_in_collection_set()") representing the
 638   // current collection set.
 639   HeapRegion* collection_set() { return _collection_set; }
 640 
 641   void clear_collection_set() { _collection_set = NULL; }
 642 
 643   // Add old region "hr" to the CSet.
 644   void add_old_region_to_cset(HeapRegion* hr);
 645 
 646   // Incremental CSet Support
 647 
 648   // The head of the incrementally built collection set.
 649   HeapRegion* inc_cset_head() { return _inc_cset_head; }
 650 
 651   // The tail of the incrementally built collection set.
 652   HeapRegion* inc_set_tail() { return _inc_cset_tail; }
 653 
 654   // Initialize incremental collection set info.
 655   void start_incremental_cset_building();
 656 
 657   // Perform any final calculations on the incremental CSet fields
 658   // before we can use them.
 659   void finalize_incremental_cset_building();
 660 
 661   void clear_incremental_cset() {
 662     _inc_cset_head = NULL;
 663     _inc_cset_tail = NULL;
 664   }
 665 
 666   // Stop adding regions to the incremental collection set
 667   void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
 668 
 669   // Add information about hr to the aggregated information for the
 670   // incrementally built collection set.
 671   void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
 672 
 673   // Update information about hr in the aggregated information for
 674   // the incrementally built collection set.
 675   void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
 676 
 677 private:
 678   // Update the incremental cset information when adding a region
 679   // (should not be called directly).
 680   void add_region_to_incremental_cset_common(HeapRegion* hr);
 681 
 682 public:
 683   // Add hr to the LHS of the incremental collection set.
 684   void add_region_to_incremental_cset_lhs(HeapRegion* hr);
 685 
 686   // Add hr to the RHS of the incremental collection set.
 687   void add_region_to_incremental_cset_rhs(HeapRegion* hr);
 688 
 689 #ifndef PRODUCT
 690   void print_collection_set(HeapRegion* list_head, outputStream* st);
 691 #endif // !PRODUCT
 692 
 693   // This sets the initiate_conc_mark_if_possible() flag to start a
 694   // new cycle, as long as we are not already in one. It's best if it
 695   // is called during a safepoint when the test whether a cycle is in
 696   // progress or not is stable.
 697   bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
 698 
 699   // This is called at the very beginning of an evacuation pause (it
 700   // has to be the first thing that the pause does). If
 701   // initiate_conc_mark_if_possible() is true, and the concurrent
 702   // marking thread has completed its work during the previous cycle,
 703   // it will set during_initial_mark_pause() to so that the pause does
 704   // the initial-mark work and start a marking cycle.
 705   void decide_on_conc_mark_initiation();
 706 
 707   // If an expansion would be appropriate, because recent GC overhead had
 708   // exceeded the desired limit, return an amount to expand by.
 709   virtual size_t expansion_amount() const;
 710 
 711   // Print tracing information.
 712   void print_tracing_info() const;
 713 
 714   // Print stats on young survival ratio
 715   void print_yg_surv_rate_info() const;
 716 
 717   void finished_recalculating_age_indexes(bool is_survivors) {
 718     if (is_survivors) {
 719       _survivor_surv_rate_group->finished_recalculating_age_indexes();
 720     } else {
 721       _short_lived_surv_rate_group->finished_recalculating_age_indexes();
 722     }
 723     // do that for any other surv rate groups
 724   }
 725 
 726   size_t young_list_target_length() const { return _young_list_target_length; }
 727 
 728   bool is_young_list_full() const;
 729 
 730   bool can_expand_young_list() const;
 731 
 732   uint young_list_max_length() const {
 733     return _young_list_max_length;
 734   }
 735 
 736   bool adaptive_young_list_length() const {
 737     return _young_gen_sizer->adaptive_young_list_length();
 738   }
 739 
 740 private:
 741   //
 742   // Survivor regions policy.
 743   //
 744 
 745   // Current tenuring threshold, set to 0 if the collector reaches the
 746   // maximum amount of survivors regions.
 747   uint _tenuring_threshold;
 748 
 749   // The limit on the number of regions allocated for survivors.
 750   uint _max_survivor_regions;
 751 
 752   // For reporting purposes.
 753   // The value of _heap_bytes_before_gc is also used to calculate
 754   // the cost of copying.
 755 
 756   size_t _eden_used_bytes_before_gc;         // Eden occupancy before GC
 757   size_t _survivor_used_bytes_before_gc;     // Survivor occupancy before GC
 758   size_t _heap_used_bytes_before_gc;         // Heap occupancy before GC
 759   size_t _metaspace_used_bytes_before_gc;    // Metaspace occupancy before GC
 760 
 761   size_t _eden_capacity_bytes_before_gc;     // Eden capacity before GC
 762   size_t _heap_capacity_bytes_before_gc;     // Heap capacity before GC
 763 
 764   // The amount of survivor regions after a collection.
 765   uint _recorded_survivor_regions;
 766   // List of survivor regions.
 767   HeapRegion* _recorded_survivor_head;
 768   HeapRegion* _recorded_survivor_tail;
 769 
 770   ageTable _survivors_age_table;
 771 
 772 public:
 773   uint tenuring_threshold() const { return _tenuring_threshold; }
 774 
 775   static const uint REGIONS_UNLIMITED = (uint) -1;
 776 
 777   uint max_regions(InCSetState dest) const {
 778     switch (dest.value()) {
 779       case InCSetState::Young:
 780         return _max_survivor_regions;
 781       case InCSetState::Old:
 782         return REGIONS_UNLIMITED;
 783       default:
 784         assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value());
 785         break;
 786     }
 787     // keep some compilers happy
 788     return 0;
 789   }
 790 
 791   void note_start_adding_survivor_regions() {
 792     _survivor_surv_rate_group->start_adding_regions();
 793   }
 794 
 795   void note_stop_adding_survivor_regions() {
 796     _survivor_surv_rate_group->stop_adding_regions();
 797   }
 798 
 799   void record_survivor_regions(uint regions,
 800                                HeapRegion* head,
 801                                HeapRegion* tail) {
 802     _recorded_survivor_regions = regions;
 803     _recorded_survivor_head    = head;
 804     _recorded_survivor_tail    = tail;
 805   }
 806 
 807   uint recorded_survivor_regions() const {
 808     return _recorded_survivor_regions;
 809   }
 810 
 811   void record_age_table(ageTable* age_table) {
 812     _survivors_age_table.merge(age_table);
 813   }
 814 
 815   void update_max_gc_locker_expansion();
 816 
 817   // Calculates survivor space parameters.
 818   void update_survivors_policy();
 819 
 820   virtual void post_heap_initialize();
 821 };
 822 
 823 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP
--- EOF ---