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 // The RSet lengths recorded for regions in the CSet. It is updated 406 // by the thread that adds a new region to the CSet. We assume that 407 // only one thread can be allocating a new CSet region (currently, 408 // it does so after taking the Heap_lock) hence no need to 409 // synchronize updates to this field. 410 size_t _inc_cset_recorded_rs_lengths; 411 412 // A concurrent refinement thread periodically samples the young 413 // region RSets and needs to update _inc_cset_recorded_rs_lengths as 414 // the RSets grow. Instead of having to synchronize updates to that 415 // field we accumulate them in this field and add it to 416 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC. 417 ssize_t _inc_cset_recorded_rs_lengths_diffs; 418 419 // The predicted elapsed time it will take to collect the regions in 420 // the CSet. This is updated by the thread that adds a new region to 421 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about 422 // MT-safety assumptions. 423 double _inc_cset_predicted_elapsed_time_ms; 424 425 // See the comment for _inc_cset_recorded_rs_lengths_diffs. 426 double _inc_cset_predicted_elapsed_time_ms_diffs; 427 428 // Stash a pointer to the g1 heap. 429 G1CollectedHeap* _g1; 430 431 G1GCPhaseTimes* _phase_times; 432 433 // The ratio of gc time to elapsed time, computed over recent pauses, 434 // and the ratio for just the last pause. 435 double _recent_avg_pause_time_ratio; 436 double _last_pause_time_ratio; 437 438 double recent_avg_pause_time_ratio() const { 439 return _recent_avg_pause_time_ratio; 440 } 441 442 // This set of variables tracks the collector efficiency, in order to 443 // determine whether we should initiate a new marking. 444 double _mark_remark_start_sec; 445 double _mark_cleanup_start_sec; 446 447 // Updates the internal young list maximum and target lengths. Returns the 448 // unbounded young list target length. 449 uint update_young_list_max_and_target_length(); 450 uint update_young_list_max_and_target_length(size_t rs_lengths); 451 452 // Update the young list target length either by setting it to the 453 // desired fixed value or by calculating it using G1's pause 454 // prediction model. If no rs_lengths parameter is passed, predict 455 // the RS lengths using the prediction model, otherwise use the 456 // given rs_lengths as the prediction. 457 // Returns the unbounded young list target length. 458 uint update_young_list_target_length(size_t rs_lengths); 459 460 // Calculate and return the minimum desired young list target 461 // length. This is the minimum desired young list length according 462 // to the user's inputs. 463 uint calculate_young_list_desired_min_length(uint base_min_length) const; 464 465 // Calculate and return the maximum desired young list target 466 // length. This is the maximum desired young list length according 467 // to the user's inputs. 468 uint calculate_young_list_desired_max_length() const; 469 470 // Calculate and return the maximum young list target length that 471 // can fit into the pause time goal. The parameters are: rs_lengths 472 // represent the prediction of how large the young RSet lengths will 473 // be, base_min_length is the already existing number of regions in 474 // the young list, min_length and max_length are the desired min and 475 // max young list length according to the user's inputs. 476 uint calculate_young_list_target_length(size_t rs_lengths, 477 uint base_min_length, 478 uint desired_min_length, 479 uint desired_max_length) const; 480 481 // Result of the bounded_young_list_target_length() method, containing both the 482 // bounded as well as the unbounded young list target lengths in this order. 483 typedef Pair<uint, uint, StackObj> YoungTargetLengths; 484 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const; 485 486 void update_rs_lengths_prediction(); 487 void update_rs_lengths_prediction(size_t prediction); 488 489 // Calculate and return chunk size (in number of regions) for parallel 490 // concurrent mark cleanup. 491 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const; 492 493 // Check whether a given young length (young_length) fits into the 494 // given target pause time and whether the prediction for the amount 495 // of objects to be copied for the given length will fit into the 496 // given free space (expressed by base_free_regions). It is used by 497 // calculate_young_list_target_length(). 498 bool predict_will_fit(uint young_length, double base_time_ms, 499 uint base_free_regions, double target_pause_time_ms) const; 500 501 // Calculate the minimum number of old regions we'll add to the CSet 502 // during a mixed GC. 503 uint calc_min_old_cset_length() const; 504 505 // Calculate the maximum number of old regions we'll add to the CSet 506 // during a mixed GC. 507 uint calc_max_old_cset_length() const; 508 509 // Returns the given amount of uncollected reclaimable space 510 // as a percentage of the current heap capacity. 511 double reclaimable_bytes_perc(size_t reclaimable_bytes) const; 512 513 // Sets up marking if proper conditions are met. 514 void maybe_start_marking(); 515 516 // The kind of STW pause. 517 enum PauseKind { 518 FullGC, 519 YoungOnlyGC, 520 MixedGC, 521 LastYoungGC, 522 InitialMarkGC, 523 Cleanup, 524 Remark 525 }; 526 527 // Calculate PauseKind from internal state. 528 PauseKind young_gc_pause_kind() const; 529 // Record the given STW pause with the given start and end times (in s). 530 void record_pause(PauseKind kind, double start, double end); 531 // Indicate that we aborted marking before doing any mixed GCs. 532 void abort_time_to_mixed_tracking(); 533 public: 534 535 G1CollectorPolicy(); 536 537 virtual ~G1CollectorPolicy(); 538 539 virtual G1CollectorPolicy* as_g1_policy() { return this; } 540 541 G1CollectorState* collector_state() const; 542 543 G1GCPhaseTimes* phase_times() const { return _phase_times; } 544 545 // Check the current value of the young list RSet lengths and 546 // compare it against the last prediction. If the current value is 547 // higher, recalculate the young list target length prediction. 548 void revise_young_list_target_length_if_necessary(); 549 550 // This should be called after the heap is resized. 551 void record_new_heap_size(uint new_number_of_regions); 552 553 void init(); 554 555 virtual void note_gc_start(uint num_active_workers); 556 557 // Create jstat counters for the policy. 558 virtual void initialize_gc_policy_counters(); 559 560 virtual HeapWord* mem_allocate_work(size_t size, 561 bool is_tlab, 562 bool* gc_overhead_limit_was_exceeded); 563 564 // This method controls how a collector handles one or more 565 // of its generations being fully allocated. 566 virtual HeapWord* satisfy_failed_allocation(size_t size, 567 bool is_tlab); 568 569 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0); 570 571 bool about_to_start_mixed_phase() const; 572 573 // Record the start and end of an evacuation pause. 574 void record_collection_pause_start(double start_time_sec); 575 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc); 576 577 // Record the start and end of a full collection. 578 void record_full_collection_start(); 579 void record_full_collection_end(); 580 581 // Must currently be called while the world is stopped. 582 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms); 583 584 // Record start and end of remark. 585 void record_concurrent_mark_remark_start(); 586 void record_concurrent_mark_remark_end(); 587 588 // Record start, end, and completion of cleanup. 589 void record_concurrent_mark_cleanup_start(); 590 void record_concurrent_mark_cleanup_end(); 591 void record_concurrent_mark_cleanup_completed(); 592 593 virtual void print_phases(); 594 595 // Record how much space we copied during a GC. This is typically 596 // called when a GC alloc region is being retired. 597 void record_bytes_copied_during_gc(size_t bytes) { 598 _bytes_copied_during_gc += bytes; 599 } 600 601 // The amount of space we copied during a GC. 602 size_t bytes_copied_during_gc() const { 603 return _bytes_copied_during_gc; 604 } 605 606 size_t collection_set_bytes_used_before() const { 607 return _collection_set_bytes_used_before; 608 } 609 610 // Determine whether there are candidate regions so that the 611 // next GC should be mixed. The two action strings are used 612 // in the ergo output when the method returns true or false. 613 bool next_gc_should_be_mixed(const char* true_action_str, 614 const char* false_action_str) const; 615 616 // Choose a new collection set. Marks the chosen regions as being 617 // "in_collection_set", and links them together. The head and number of 618 // the collection set are available via access methods. 619 double finalize_young_cset_part(double target_pause_time_ms); 620 virtual void finalize_old_cset_part(double time_remaining_ms); 621 622 // The head of the list (via "next_in_collection_set()") representing the 623 // current collection set. 624 HeapRegion* collection_set() { return _collection_set; } 625 626 void clear_collection_set() { _collection_set = NULL; } 627 628 // Add old region "hr" to the CSet. 629 void add_old_region_to_cset(HeapRegion* hr); 630 631 // Incremental CSet Support 632 633 // The head of the incrementally built collection set. 634 HeapRegion* inc_cset_head() { return _inc_cset_head; } 635 636 // The tail of the incrementally built collection set. 637 HeapRegion* inc_set_tail() { return _inc_cset_tail; } 638 639 // Initialize incremental collection set info. 640 void start_incremental_cset_building(); 641 642 // Perform any final calculations on the incremental CSet fields 643 // before we can use them. 644 void finalize_incremental_cset_building(); 645 646 void clear_incremental_cset() { 647 _inc_cset_head = NULL; 648 _inc_cset_tail = NULL; 649 } 650 651 // Stop adding regions to the incremental collection set 652 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; } 653 654 // Add information about hr to the aggregated information for the 655 // incrementally built collection set. 656 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length); 657 658 // Update information about hr in the aggregated information for 659 // the incrementally built collection set. 660 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length); 661 662 private: 663 // Update the incremental cset information when adding a region 664 // (should not be called directly). 665 void add_region_to_incremental_cset_common(HeapRegion* hr); 666 667 // Set the state to start a concurrent marking cycle and clear 668 // _initiate_conc_mark_if_possible because it has now been 669 // acted on. 670 void initiate_conc_mark(); 671 672 public: 673 // Add hr to the LHS of the incremental collection set. 674 void add_region_to_incremental_cset_lhs(HeapRegion* hr); 675 676 // Add hr to the RHS of the incremental collection set. 677 void add_region_to_incremental_cset_rhs(HeapRegion* hr); 678 679 #ifndef PRODUCT 680 void print_collection_set(HeapRegion* list_head, outputStream* st); 681 #endif // !PRODUCT 682 683 // This sets the initiate_conc_mark_if_possible() flag to start a 684 // new cycle, as long as we are not already in one. It's best if it 685 // is called during a safepoint when the test whether a cycle is in 686 // progress or not is stable. 687 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause); 688 689 // This is called at the very beginning of an evacuation pause (it 690 // has to be the first thing that the pause does). If 691 // initiate_conc_mark_if_possible() is true, and the concurrent 692 // marking thread has completed its work during the previous cycle, 693 // it will set during_initial_mark_pause() to so that the pause does 694 // the initial-mark work and start a marking cycle. 695 void decide_on_conc_mark_initiation(); 696 697 // If an expansion would be appropriate, because recent GC overhead had 698 // exceeded the desired limit, return an amount to expand by. 699 virtual size_t expansion_amount(); 700 701 // Clear ratio tracking data used by expansion_amount(). 702 void clear_ratio_check_data(); 703 704 // Print stats on young survival ratio 705 void print_yg_surv_rate_info() const; 706 707 void finished_recalculating_age_indexes(bool is_survivors) { 708 if (is_survivors) { 709 _survivor_surv_rate_group->finished_recalculating_age_indexes(); 710 } else { 711 _short_lived_surv_rate_group->finished_recalculating_age_indexes(); 712 } 713 // do that for any other surv rate groups 714 } 715 716 size_t young_list_target_length() const { return _young_list_target_length; } 717 718 bool is_young_list_full() const; 719 720 bool can_expand_young_list() const; 721 722 uint young_list_max_length() const { 723 return _young_list_max_length; 724 } 725 726 bool adaptive_young_list_length() const { 727 return _young_gen_sizer->adaptive_young_list_length(); 728 } 729 730 virtual bool should_process_references() const { 731 return true; 732 } 733 734 private: 735 // 736 // Survivor regions policy. 737 // 738 739 // Current tenuring threshold, set to 0 if the collector reaches the 740 // maximum amount of survivors regions. 741 uint _tenuring_threshold; 742 743 // The limit on the number of regions allocated for survivors. 744 uint _max_survivor_regions; 745 746 // For reporting purposes. 747 // The value of _heap_bytes_before_gc is also used to calculate 748 // the cost of copying. 749 750 // The amount of survivor regions after a collection. 751 uint _recorded_survivor_regions; 752 // List of survivor regions. 753 HeapRegion* _recorded_survivor_head; 754 HeapRegion* _recorded_survivor_tail; 755 756 AgeTable _survivors_age_table; 757 758 public: 759 uint tenuring_threshold() const { return _tenuring_threshold; } 760 761 uint max_survivor_regions() { 762 return _max_survivor_regions; 763 } 764 765 static const uint REGIONS_UNLIMITED = (uint) -1; 766 767 uint max_regions(InCSetState dest) const { 768 switch (dest.value()) { 769 case InCSetState::Young: 770 return _max_survivor_regions; 771 case InCSetState::Old: 772 return REGIONS_UNLIMITED; 773 default: 774 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value()); 775 break; 776 } 777 // keep some compilers happy 778 return 0; 779 } 780 781 void note_start_adding_survivor_regions() { 782 _survivor_surv_rate_group->start_adding_regions(); 783 } 784 785 void note_stop_adding_survivor_regions() { 786 _survivor_surv_rate_group->stop_adding_regions(); 787 } 788 789 void record_survivor_regions(uint regions, 790 HeapRegion* head, 791 HeapRegion* tail) { 792 _recorded_survivor_regions = regions; 793 _recorded_survivor_head = head; 794 _recorded_survivor_tail = tail; 795 } 796 797 uint recorded_survivor_regions() const { 798 return _recorded_survivor_regions; 799 } 800 801 void record_age_table(AgeTable* age_table) { 802 _survivors_age_table.merge(age_table); 803 } 804 805 void update_max_gc_locker_expansion(); 806 807 // Calculates survivor space parameters. 808 void update_survivors_policy(); 809 810 virtual void post_heap_initialize(); 811 }; 812 813 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP