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 // TraceYoungGenTime collects data on _both_ young and mixed evacuation pauses 48 // (the latter may contain non-young regions - i.e. regions that are 49 // technically in old) while TraceOldGenTime collects data about full GCs. 50 class TraceYoungGenTimeData : public CHeapObj<mtGC> { 51 private: 52 unsigned _young_pause_num; 53 unsigned _mixed_pause_num; 54 55 NumberSeq _all_stop_world_times_ms; 56 NumberSeq _all_yield_times_ms; 57 58 NumberSeq _total; 59 NumberSeq _other; 60 NumberSeq _root_region_scan_wait; 61 NumberSeq _parallel; 62 NumberSeq _ext_root_scan; 63 NumberSeq _satb_filtering; 64 NumberSeq _update_rs; 65 NumberSeq _scan_rs; 66 NumberSeq _obj_copy; 67 NumberSeq _termination; 68 NumberSeq _parallel_other; 69 NumberSeq _clear_ct; 70 71 void print_summary(const char* str, const NumberSeq* seq) const; 72 void print_summary_sd(const char* str, const NumberSeq* seq) const; 73 74 public: 75 TraceYoungGenTimeData() : _young_pause_num(0), _mixed_pause_num(0) {}; 76 void record_start_collection(double time_to_stop_the_world_ms); 77 void record_yield_time(double yield_time_ms); 78 void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times); 79 void increment_young_collection_count(); 80 void increment_mixed_collection_count(); 81 void print() const; 82 }; 83 84 class TraceOldGenTimeData : public CHeapObj<mtGC> { 85 private: 86 NumberSeq _all_full_gc_times; 87 88 public: 89 void record_full_collection(double full_gc_time_ms); 90 void print() const; 91 }; 92 93 // There are three command line options related to the young gen size: 94 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is 95 // just a short form for NewSize==MaxNewSize). G1 will use its internal 96 // heuristics to calculate the actual young gen size, so these options 97 // basically only limit the range within which G1 can pick a young gen 98 // size. Also, these are general options taking byte sizes. G1 will 99 // internally work with a number of regions instead. So, some rounding 100 // will occur. 101 // 102 // If nothing related to the the young gen size is set on the command 103 // line we should allow the young gen to be between G1NewSizePercent 104 // and G1MaxNewSizePercent of the heap size. This means that every time 105 // the heap size changes, the limits for the young gen size will be 106 // recalculated. 107 // 108 // If only -XX:NewSize is set we should use the specified value as the 109 // minimum size for young gen. Still using G1MaxNewSizePercent of the 110 // heap as maximum. 111 // 112 // If only -XX:MaxNewSize is set we should use the specified value as the 113 // maximum size for young gen. Still using G1NewSizePercent of the heap 114 // as minimum. 115 // 116 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values. 117 // No updates when the heap size changes. There is a special case when 118 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a 119 // different heuristic for calculating the collection set when we do mixed 120 // collection. 121 // 122 // If only -XX:NewRatio is set we should use the specified ratio of the heap 123 // as both min and max. This will be interpreted as "fixed" just like the 124 // NewSize==MaxNewSize case above. But we will update the min and max 125 // every time the heap size changes. 126 // 127 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is 128 // combined with either NewSize or MaxNewSize. (A warning message is printed.) 129 class G1YoungGenSizer : public CHeapObj<mtGC> { 130 private: 131 enum SizerKind { 132 SizerDefaults, 133 SizerNewSizeOnly, 134 SizerMaxNewSizeOnly, 135 SizerMaxAndNewSize, 136 SizerNewRatio 137 }; 138 SizerKind _sizer_kind; 139 uint _min_desired_young_length; 140 uint _max_desired_young_length; 141 bool _adaptive_size; 142 uint calculate_default_min_length(uint new_number_of_heap_regions); 143 uint calculate_default_max_length(uint new_number_of_heap_regions); 144 145 // Update the given values for minimum and maximum young gen length in regions 146 // given the number of heap regions depending on the kind of sizing algorithm. 147 void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length); 148 149 public: 150 G1YoungGenSizer(); 151 // Calculate the maximum length of the young gen given the number of regions 152 // depending on the sizing algorithm. 153 uint max_young_length(uint number_of_heap_regions); 154 155 void heap_size_changed(uint new_number_of_heap_regions); 156 uint min_desired_young_length() { 157 return _min_desired_young_length; 158 } 159 uint max_desired_young_length() { 160 return _max_desired_young_length; 161 } 162 163 bool adaptive_young_list_length() const { 164 return _adaptive_size; 165 } 166 }; 167 168 class G1CollectorPolicy: public CollectorPolicy { 169 private: 170 G1IHOPControl* _ihop_control; 171 172 G1IHOPControl* create_ihop_control() const; 173 // Update the IHOP control with necessary statistics. 174 void update_ihop_prediction(double mutator_time_s, 175 size_t mutator_alloc_bytes, 176 size_t young_gen_size); 177 void report_ihop_statistics(); 178 179 G1Predictions _predictor; 180 181 double get_new_prediction(TruncatedSeq const* seq) const; 182 size_t get_new_size_prediction(TruncatedSeq const* seq) const; 183 184 // either equal to the number of parallel threads, if ParallelGCThreads 185 // has been set, or 1 otherwise 186 int _parallel_gc_threads; 187 188 // The number of GC threads currently active. 189 uintx _no_of_gc_threads; 190 191 G1MMUTracker* _mmu_tracker; 192 193 void initialize_alignments(); 194 void initialize_flags(); 195 196 CollectionSetChooser* _cset_chooser; 197 198 double _full_collection_start_sec; 199 200 // These exclude marking times. 201 TruncatedSeq* _recent_gc_times_ms; 202 203 TruncatedSeq* _concurrent_mark_remark_times_ms; 204 TruncatedSeq* _concurrent_mark_cleanup_times_ms; 205 206 // Ratio check data for determining if heap growth is necessary. 207 uint _ratio_over_threshold_count; 208 double _ratio_over_threshold_sum; 209 uint _pauses_since_start; 210 211 TraceYoungGenTimeData _trace_young_gen_time_data; 212 TraceOldGenTimeData _trace_old_gen_time_data; 213 214 double _stop_world_start; 215 216 uint _young_list_target_length; 217 uint _young_list_fixed_length; 218 219 // The max number of regions we can extend the eden by while the GC 220 // locker is active. This should be >= _young_list_target_length; 221 uint _young_list_max_length; 222 223 SurvRateGroup* _short_lived_surv_rate_group; 224 SurvRateGroup* _survivor_surv_rate_group; 225 // add here any more surv rate groups 226 227 double _gc_overhead_perc; 228 229 double _reserve_factor; 230 uint _reserve_regions; 231 232 enum PredictionConstants { 233 TruncatedSeqLength = 10, 234 NumPrevPausesForHeuristics = 10, 235 // MinOverThresholdForGrowth must be less than NumPrevPausesForHeuristics, 236 // representing the minimum number of pause time ratios that exceed 237 // GCTimeRatio before a heap expansion will be triggered. 238 MinOverThresholdForGrowth = 4 239 }; 240 241 TruncatedSeq* _alloc_rate_ms_seq; 242 double _prev_collection_pause_end_ms; 243 244 TruncatedSeq* _rs_length_diff_seq; 245 TruncatedSeq* _cost_per_card_ms_seq; 246 TruncatedSeq* _cost_scan_hcc_seq; 247 TruncatedSeq* _young_cards_per_entry_ratio_seq; 248 TruncatedSeq* _mixed_cards_per_entry_ratio_seq; 249 TruncatedSeq* _cost_per_entry_ms_seq; 250 TruncatedSeq* _mixed_cost_per_entry_ms_seq; 251 TruncatedSeq* _cost_per_byte_ms_seq; 252 TruncatedSeq* _constant_other_time_ms_seq; 253 TruncatedSeq* _young_other_cost_per_region_ms_seq; 254 TruncatedSeq* _non_young_other_cost_per_region_ms_seq; 255 256 TruncatedSeq* _pending_cards_seq; 257 TruncatedSeq* _rs_lengths_seq; 258 259 TruncatedSeq* _cost_per_byte_ms_during_cm_seq; 260 261 G1YoungGenSizer* _young_gen_sizer; 262 263 uint _eden_cset_region_length; 264 uint _survivor_cset_region_length; 265 uint _old_cset_region_length; 266 267 void init_cset_region_lengths(uint eden_cset_region_length, 268 uint survivor_cset_region_length); 269 270 uint eden_cset_region_length() const { return _eden_cset_region_length; } 271 uint survivor_cset_region_length() const { return _survivor_cset_region_length; } 272 uint old_cset_region_length() const { return _old_cset_region_length; } 273 274 uint _free_regions_at_end_of_collection; 275 276 size_t _recorded_rs_lengths; 277 size_t _max_rs_lengths; 278 279 size_t _rs_lengths_prediction; 280 281 #ifndef PRODUCT 282 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group); 283 #endif // PRODUCT 284 285 void adjust_concurrent_refinement(double update_rs_time, 286 double update_rs_processed_buffers, 287 double goal_ms); 288 289 uintx no_of_gc_threads() { return _no_of_gc_threads; } 290 void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; } 291 292 double _pause_time_target_ms; 293 294 size_t _pending_cards; 295 296 // The amount of allocated bytes in old gen during the last mutator and the following 297 // young GC phase. 298 size_t _bytes_allocated_in_old_since_last_gc; 299 300 G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed; 301 public: 302 const G1Predictions& predictor() const { return _predictor; } 303 304 // Add the given number of bytes to the total number of allocated bytes in the old gen. 305 void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; } 306 307 // Accessors 308 309 void set_region_eden(HeapRegion* hr, int young_index_in_cset) { 310 hr->set_eden(); 311 hr->install_surv_rate_group(_short_lived_surv_rate_group); 312 hr->set_young_index_in_cset(young_index_in_cset); 313 } 314 315 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) { 316 assert(hr->is_survivor(), "pre-condition"); 317 hr->install_surv_rate_group(_survivor_surv_rate_group); 318 hr->set_young_index_in_cset(young_index_in_cset); 319 } 320 321 #ifndef PRODUCT 322 bool verify_young_ages(); 323 #endif // PRODUCT 324 325 void record_max_rs_lengths(size_t rs_lengths) { 326 _max_rs_lengths = rs_lengths; 327 } 328 329 size_t predict_rs_length_diff() const; 330 331 double predict_alloc_rate_ms() const; 332 333 double predict_cost_per_card_ms() const; 334 335 double predict_scan_hcc_ms() const; 336 337 double predict_rs_update_time_ms(size_t pending_cards) const; 338 339 double predict_young_cards_per_entry_ratio() const; 340 341 double predict_mixed_cards_per_entry_ratio() const; 342 343 size_t predict_young_card_num(size_t rs_length) const; 344 345 size_t predict_non_young_card_num(size_t rs_length) const; 346 347 double predict_rs_scan_time_ms(size_t card_num) const; 348 349 double predict_mixed_rs_scan_time_ms(size_t card_num) const; 350 351 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const; 352 353 double predict_object_copy_time_ms(size_t bytes_to_copy) const; 354 355 double predict_constant_other_time_ms() const; 356 357 double predict_young_other_time_ms(size_t young_num) const; 358 359 double predict_non_young_other_time_ms(size_t non_young_num) const; 360 361 double predict_base_elapsed_time_ms(size_t pending_cards) const; 362 double predict_base_elapsed_time_ms(size_t pending_cards, 363 size_t scanned_cards) const; 364 size_t predict_bytes_to_copy(HeapRegion* hr) const; 365 double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const; 366 367 void set_recorded_rs_lengths(size_t rs_lengths); 368 369 uint cset_region_length() const { return young_cset_region_length() + 370 old_cset_region_length(); } 371 uint young_cset_region_length() const { return eden_cset_region_length() + 372 survivor_cset_region_length(); } 373 374 double predict_survivor_regions_evac_time() const; 375 376 bool should_update_surv_rate_group_predictors() { 377 return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window(); 378 } 379 380 void cset_regions_freed() { 381 bool update = should_update_surv_rate_group_predictors(); 382 383 _short_lived_surv_rate_group->all_surviving_words_recorded(update); 384 _survivor_surv_rate_group->all_surviving_words_recorded(update); 385 } 386 387 G1MMUTracker* mmu_tracker() { 388 return _mmu_tracker; 389 } 390 391 const G1MMUTracker* mmu_tracker() const { 392 return _mmu_tracker; 393 } 394 395 double max_pause_time_ms() const { 396 return _mmu_tracker->max_gc_time() * 1000.0; 397 } 398 399 double predict_remark_time_ms() const; 400 401 double predict_cleanup_time_ms() const; 402 403 // Returns an estimate of the survival rate of the region at yg-age 404 // "yg_age". 405 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const; 406 407 double predict_yg_surv_rate(int age) const; 408 409 double accum_yg_surv_rate_pred(int age) const; 410 411 protected: 412 virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const; 413 virtual double other_time_ms(double pause_time_ms) const; 414 415 double young_other_time_ms() const; 416 double non_young_other_time_ms() const; 417 double constant_other_time_ms(double pause_time_ms) const; 418 419 CollectionSetChooser* cset_chooser() const { 420 return _cset_chooser; 421 } 422 423 private: 424 // Statistics kept per GC stoppage, pause or full. 425 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec; 426 427 // Add a new GC of the given duration and end time to the record. 428 void update_recent_gc_times(double end_time_sec, double elapsed_ms); 429 430 // The head of the list (via "next_in_collection_set()") representing the 431 // current collection set. Set from the incrementally built collection 432 // set at the start of the pause. 433 HeapRegion* _collection_set; 434 435 // The number of bytes in the collection set before the pause. Set from 436 // the incrementally built collection set at the start of an evacuation 437 // pause, and incremented in finalize_old_cset_part() when adding old regions 438 // (if any) to the collection set. 439 size_t _collection_set_bytes_used_before; 440 441 // The number of bytes copied during the GC. 442 size_t _bytes_copied_during_gc; 443 444 // The associated information that is maintained while the incremental 445 // collection set is being built with young regions. Used to populate 446 // the recorded info for the evacuation pause. 447 448 enum CSetBuildType { 449 Active, // We are actively building the collection set 450 Inactive // We are not actively building the collection set 451 }; 452 453 CSetBuildType _inc_cset_build_state; 454 455 // The head of the incrementally built collection set. 456 HeapRegion* _inc_cset_head; 457 458 // The tail of the incrementally built collection set. 459 HeapRegion* _inc_cset_tail; 460 461 // The number of bytes in the incrementally built collection set. 462 // Used to set _collection_set_bytes_used_before at the start of 463 // an evacuation pause. 464 size_t _inc_cset_bytes_used_before; 465 466 // Used to record the highest end of heap region in collection set 467 HeapWord* _inc_cset_max_finger; 468 469 // The RSet lengths recorded for regions in the CSet. It is updated 470 // by the thread that adds a new region to the CSet. We assume that 471 // only one thread can be allocating a new CSet region (currently, 472 // it does so after taking the Heap_lock) hence no need to 473 // synchronize updates to this field. 474 size_t _inc_cset_recorded_rs_lengths; 475 476 // A concurrent refinement thread periodically samples the young 477 // region RSets and needs to update _inc_cset_recorded_rs_lengths as 478 // the RSets grow. Instead of having to synchronize updates to that 479 // field we accumulate them in this field and add it to 480 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC. 481 ssize_t _inc_cset_recorded_rs_lengths_diffs; 482 483 // The predicted elapsed time it will take to collect the regions in 484 // the CSet. This is updated by the thread that adds a new region to 485 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about 486 // MT-safety assumptions. 487 double _inc_cset_predicted_elapsed_time_ms; 488 489 // See the comment for _inc_cset_recorded_rs_lengths_diffs. 490 double _inc_cset_predicted_elapsed_time_ms_diffs; 491 492 // Stash a pointer to the g1 heap. 493 G1CollectedHeap* _g1; 494 495 G1GCPhaseTimes* _phase_times; 496 497 // The ratio of gc time to elapsed time, computed over recent pauses, 498 // and the ratio for just the last pause. 499 double _recent_avg_pause_time_ratio; 500 double _last_pause_time_ratio; 501 502 double recent_avg_pause_time_ratio() const { 503 return _recent_avg_pause_time_ratio; 504 } 505 506 // This set of variables tracks the collector efficiency, in order to 507 // determine whether we should initiate a new marking. 508 double _mark_remark_start_sec; 509 double _mark_cleanup_start_sec; 510 511 // Updates the internal young list maximum and target lengths. Returns the 512 // unbounded young list target length. 513 uint update_young_list_max_and_target_length(); 514 uint update_young_list_max_and_target_length(size_t rs_lengths); 515 516 // Update the young list target length either by setting it to the 517 // desired fixed value or by calculating it using G1's pause 518 // prediction model. If no rs_lengths parameter is passed, predict 519 // the RS lengths using the prediction model, otherwise use the 520 // given rs_lengths as the prediction. 521 // Returns the unbounded young list target length. 522 uint update_young_list_target_length(size_t rs_lengths); 523 524 // Calculate and return the minimum desired young list target 525 // length. This is the minimum desired young list length according 526 // to the user's inputs. 527 uint calculate_young_list_desired_min_length(uint base_min_length) const; 528 529 // Calculate and return the maximum desired young list target 530 // length. This is the maximum desired young list length according 531 // to the user's inputs. 532 uint calculate_young_list_desired_max_length() const; 533 534 // Calculate and return the maximum young list target length that 535 // can fit into the pause time goal. The parameters are: rs_lengths 536 // represent the prediction of how large the young RSet lengths will 537 // be, base_min_length is the already existing number of regions in 538 // the young list, min_length and max_length are the desired min and 539 // max young list length according to the user's inputs. 540 uint calculate_young_list_target_length(size_t rs_lengths, 541 uint base_min_length, 542 uint desired_min_length, 543 uint desired_max_length) const; 544 545 // Result of the bounded_young_list_target_length() method, containing both the 546 // bounded as well as the unbounded young list target lengths in this order. 547 typedef Pair<uint, uint, StackObj> YoungTargetLengths; 548 YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const; 549 550 void update_rs_lengths_prediction(); 551 void update_rs_lengths_prediction(size_t prediction); 552 553 // Calculate and return chunk size (in number of regions) for parallel 554 // concurrent mark cleanup. 555 uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const; 556 557 // Check whether a given young length (young_length) fits into the 558 // given target pause time and whether the prediction for the amount 559 // of objects to be copied for the given length will fit into the 560 // given free space (expressed by base_free_regions). It is used by 561 // calculate_young_list_target_length(). 562 bool predict_will_fit(uint young_length, double base_time_ms, 563 uint base_free_regions, double target_pause_time_ms) const; 564 565 // Calculate the minimum number of old regions we'll add to the CSet 566 // during a mixed GC. 567 uint calc_min_old_cset_length() const; 568 569 // Calculate the maximum number of old regions we'll add to the CSet 570 // during a mixed GC. 571 uint calc_max_old_cset_length() const; 572 573 // Returns the given amount of uncollected reclaimable space 574 // as a percentage of the current heap capacity. 575 double reclaimable_bytes_perc(size_t reclaimable_bytes) const; 576 577 // Sets up marking if proper conditions are met. 578 void maybe_start_marking(); 579 580 // The kind of STW pause. 581 enum PauseKind { 582 FullGC, 583 YoungOnlyGC, 584 MixedGC, 585 LastYoungGC, 586 InitialMarkGC, 587 Cleanup, 588 Remark 589 }; 590 591 // Calculate PauseKind from internal state. 592 PauseKind young_gc_pause_kind() const; 593 // Record the given STW pause with the given start and end times (in s). 594 void record_pause(PauseKind kind, double start, double end); 595 // Indicate that we aborted marking before doing any mixed GCs. 596 void abort_time_to_mixed_tracking(); 597 public: 598 599 G1CollectorPolicy(); 600 601 virtual ~G1CollectorPolicy(); 602 603 virtual G1CollectorPolicy* as_g1_policy() { return this; } 604 605 G1CollectorState* collector_state() const; 606 607 G1GCPhaseTimes* phase_times() const { return _phase_times; } 608 609 // Check the current value of the young list RSet lengths and 610 // compare it against the last prediction. If the current value is 611 // higher, recalculate the young list target length prediction. 612 void revise_young_list_target_length_if_necessary(); 613 614 // This should be called after the heap is resized. 615 void record_new_heap_size(uint new_number_of_regions); 616 617 void init(); 618 619 virtual void note_gc_start(uint num_active_workers); 620 621 // Create jstat counters for the policy. 622 virtual void initialize_gc_policy_counters(); 623 624 virtual HeapWord* mem_allocate_work(size_t size, 625 bool is_tlab, 626 bool* gc_overhead_limit_was_exceeded); 627 628 // This method controls how a collector handles one or more 629 // of its generations being fully allocated. 630 virtual HeapWord* satisfy_failed_allocation(size_t size, 631 bool is_tlab); 632 633 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0); 634 635 bool about_to_start_mixed_phase() const; 636 637 // Record the start and end of an evacuation pause. 638 void record_collection_pause_start(double start_time_sec); 639 void record_collection_pause_end(double pause_time_ms, size_t cards_scanned); 640 641 // Record the start and end of a full collection. 642 void record_full_collection_start(); 643 void record_full_collection_end(); 644 645 // Must currently be called while the world is stopped. 646 void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms); 647 648 // Record start and end of remark. 649 void record_concurrent_mark_remark_start(); 650 void record_concurrent_mark_remark_end(); 651 652 // Record start, end, and completion of cleanup. 653 void record_concurrent_mark_cleanup_start(); 654 void record_concurrent_mark_cleanup_end(); 655 void record_concurrent_mark_cleanup_completed(); 656 657 // Records the information about the heap size for reporting in 658 // print_detailed_heap_transition 659 void record_heap_size_info_at_start(bool full); 660 661 // Print heap sizing transition (with less and more detail). 662 663 void print_detailed_heap_transition() const; 664 665 virtual void print_phases(double pause_time_ms); 666 667 void record_stop_world_start(); 668 void record_concurrent_pause(); 669 670 // Record how much space we copied during a GC. This is typically 671 // called when a GC alloc region is being retired. 672 void record_bytes_copied_during_gc(size_t bytes) { 673 _bytes_copied_during_gc += bytes; 674 } 675 676 // The amount of space we copied during a GC. 677 size_t bytes_copied_during_gc() const { 678 return _bytes_copied_during_gc; 679 } 680 681 size_t collection_set_bytes_used_before() const { 682 return _collection_set_bytes_used_before; 683 } 684 685 // Determine whether there are candidate regions so that the 686 // next GC should be mixed. The two action strings are used 687 // in the ergo output when the method returns true or false. 688 bool next_gc_should_be_mixed(const char* true_action_str, 689 const char* false_action_str) const; 690 691 // Choose a new collection set. Marks the chosen regions as being 692 // "in_collection_set", and links them together. The head and number of 693 // the collection set are available via access methods. 694 double finalize_young_cset_part(double target_pause_time_ms); 695 virtual void finalize_old_cset_part(double time_remaining_ms); 696 697 // The head of the list (via "next_in_collection_set()") representing the 698 // current collection set. 699 HeapRegion* collection_set() { return _collection_set; } 700 701 void clear_collection_set() { _collection_set = NULL; } 702 703 // Add old region "hr" to the CSet. 704 void add_old_region_to_cset(HeapRegion* hr); 705 706 // Incremental CSet Support 707 708 // The head of the incrementally built collection set. 709 HeapRegion* inc_cset_head() { return _inc_cset_head; } 710 711 // The tail of the incrementally built collection set. 712 HeapRegion* inc_set_tail() { return _inc_cset_tail; } 713 714 // Initialize incremental collection set info. 715 void start_incremental_cset_building(); 716 717 // Perform any final calculations on the incremental CSet fields 718 // before we can use them. 719 void finalize_incremental_cset_building(); 720 721 void clear_incremental_cset() { 722 _inc_cset_head = NULL; 723 _inc_cset_tail = NULL; 724 } 725 726 // Stop adding regions to the incremental collection set 727 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; } 728 729 // Add information about hr to the aggregated information for the 730 // incrementally built collection set. 731 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length); 732 733 // Update information about hr in the aggregated information for 734 // the incrementally built collection set. 735 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length); 736 737 private: 738 // Update the incremental cset information when adding a region 739 // (should not be called directly). 740 void add_region_to_incremental_cset_common(HeapRegion* hr); 741 742 // Set the state to start a concurrent marking cycle and clear 743 // _initiate_conc_mark_if_possible because it has now been 744 // acted on. 745 void initiate_conc_mark(); 746 747 public: 748 // Add hr to the LHS of the incremental collection set. 749 void add_region_to_incremental_cset_lhs(HeapRegion* hr); 750 751 // Add hr to the RHS of the incremental collection set. 752 void add_region_to_incremental_cset_rhs(HeapRegion* hr); 753 754 #ifndef PRODUCT 755 void print_collection_set(HeapRegion* list_head, outputStream* st); 756 #endif // !PRODUCT 757 758 // This sets the initiate_conc_mark_if_possible() flag to start a 759 // new cycle, as long as we are not already in one. It's best if it 760 // is called during a safepoint when the test whether a cycle is in 761 // progress or not is stable. 762 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause); 763 764 // This is called at the very beginning of an evacuation pause (it 765 // has to be the first thing that the pause does). If 766 // initiate_conc_mark_if_possible() is true, and the concurrent 767 // marking thread has completed its work during the previous cycle, 768 // it will set during_initial_mark_pause() to so that the pause does 769 // the initial-mark work and start a marking cycle. 770 void decide_on_conc_mark_initiation(); 771 772 // If an expansion would be appropriate, because recent GC overhead had 773 // exceeded the desired limit, return an amount to expand by. 774 virtual size_t expansion_amount(); 775 776 // Clear ratio tracking data used by expansion_amount(). 777 void clear_ratio_check_data(); 778 779 // Print tracing information. 780 void print_tracing_info() const; 781 782 // Print stats on young survival ratio 783 void print_yg_surv_rate_info() const; 784 785 void finished_recalculating_age_indexes(bool is_survivors) { 786 if (is_survivors) { 787 _survivor_surv_rate_group->finished_recalculating_age_indexes(); 788 } else { 789 _short_lived_surv_rate_group->finished_recalculating_age_indexes(); 790 } 791 // do that for any other surv rate groups 792 } 793 794 size_t young_list_target_length() const { return _young_list_target_length; } 795 796 bool is_young_list_full() const; 797 798 bool can_expand_young_list() const; 799 800 uint young_list_max_length() const { 801 return _young_list_max_length; 802 } 803 804 bool adaptive_young_list_length() const { 805 return _young_gen_sizer->adaptive_young_list_length(); 806 } 807 808 virtual bool should_process_references() const { 809 return true; 810 } 811 812 private: 813 // 814 // Survivor regions policy. 815 // 816 817 // Current tenuring threshold, set to 0 if the collector reaches the 818 // maximum amount of survivors regions. 819 uint _tenuring_threshold; 820 821 // The limit on the number of regions allocated for survivors. 822 uint _max_survivor_regions; 823 824 // For reporting purposes. 825 // The value of _heap_bytes_before_gc is also used to calculate 826 // the cost of copying. 827 828 size_t _eden_used_bytes_before_gc; // Eden occupancy before GC 829 size_t _survivor_used_bytes_before_gc; // Survivor occupancy before GC 830 size_t _old_used_bytes_before_gc; // Old occupancy before GC 831 size_t _humongous_used_bytes_before_gc; // Humongous occupancy before GC 832 size_t _heap_used_bytes_before_gc; // Heap occupancy before GC 833 size_t _metaspace_used_bytes_before_gc; // Metaspace occupancy before GC 834 835 size_t _eden_capacity_bytes_before_gc; // Eden capacity before GC 836 size_t _heap_capacity_bytes_before_gc; // Heap capacity before GC 837 838 // The amount of survivor regions after a collection. 839 uint _recorded_survivor_regions; 840 // List of survivor regions. 841 HeapRegion* _recorded_survivor_head; 842 HeapRegion* _recorded_survivor_tail; 843 844 AgeTable _survivors_age_table; 845 846 public: 847 uint tenuring_threshold() const { return _tenuring_threshold; } 848 849 static const uint REGIONS_UNLIMITED = (uint) -1; 850 851 uint max_regions(InCSetState dest) const { 852 switch (dest.value()) { 853 case InCSetState::Young: 854 return _max_survivor_regions; 855 case InCSetState::Old: 856 return REGIONS_UNLIMITED; 857 default: 858 assert(false, "Unknown dest state: " CSETSTATE_FORMAT, dest.value()); 859 break; 860 } 861 // keep some compilers happy 862 return 0; 863 } 864 865 void note_start_adding_survivor_regions() { 866 _survivor_surv_rate_group->start_adding_regions(); 867 } 868 869 void note_stop_adding_survivor_regions() { 870 _survivor_surv_rate_group->stop_adding_regions(); 871 } 872 873 void record_survivor_regions(uint regions, 874 HeapRegion* head, 875 HeapRegion* tail) { 876 _recorded_survivor_regions = regions; 877 _recorded_survivor_head = head; 878 _recorded_survivor_tail = tail; 879 } 880 881 uint recorded_survivor_regions() const { 882 return _recorded_survivor_regions; 883 } 884 885 void record_age_table(AgeTable* age_table) { 886 _survivors_age_table.merge(age_table); 887 } 888 889 void update_max_gc_locker_expansion(); 890 891 // Calculates survivor space parameters. 892 void update_survivors_policy(); 893 894 virtual void post_heap_initialize(); 895 }; 896 897 #endif // SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP