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