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