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