| /* |
| * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
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| * |
| */ |
| |
| #ifndef SHARE_GC_G1_G1POLICY_HPP |
| #define SHARE_GC_G1_G1POLICY_HPP |
| |
| #include "gc/g1/g1CollectorState.hpp" |
| #include "gc/g1/g1GCPhaseTimes.hpp" |
| #include "gc/g1/g1InCSetState.hpp" |
| #include "gc/g1/g1InitialMarkToMixedTimeTracker.hpp" |
| #include "gc/g1/g1MMUTracker.hpp" |
| #include "gc/g1/g1RemSetTrackingPolicy.hpp" |
| #include "gc/g1/g1Predictions.hpp" |
| #include "gc/g1/g1YoungGenSizer.hpp" |
| #include "gc/shared/gcCause.hpp" |
| #include "utilities/pair.hpp" |
| |
| // A G1Policy makes policy decisions that determine the |
| // characteristics of the collector. Examples include: |
| // * choice of collection set. |
| // * when to collect. |
| |
| class HeapRegion; |
| class G1CollectionSet; |
| class G1CollectionSetCandidates; |
| class G1CollectionSetChooser; |
| class G1IHOPControl; |
| class G1Analytics; |
| class G1SurvivorRegions; |
| class G1YoungGenSizer; |
| class GCPolicyCounters; |
| class STWGCTimer; |
| |
| class G1Policy: public CHeapObj<mtGC> { |
| private: |
| |
| static G1IHOPControl* create_ihop_control(const G1Predictions* predictor); |
| // Update the IHOP control with necessary statistics. |
| void update_ihop_prediction(double mutator_time_s, |
| size_t mutator_alloc_bytes, |
| size_t young_gen_size, |
| bool this_gc_was_young_only); |
| void report_ihop_statistics(); |
| |
| G1Predictions _predictor; |
| G1Analytics* _analytics; |
| G1RemSetTrackingPolicy _remset_tracker; |
| G1MMUTracker* _mmu_tracker; |
| G1IHOPControl* _ihop_control; |
| |
| GCPolicyCounters* _policy_counters; |
| |
| double _full_collection_start_sec; |
| |
| jlong _collection_pause_end_millis; |
| |
| uint _young_list_target_length; |
| uint _young_list_fixed_length; |
| |
| // The max number of regions we can extend the eden by while the GC |
| // locker is active. This should be >= _young_list_target_length; |
| uint _young_list_max_length; |
| |
| // SurvRateGroups below must be initialized after the predictor because they |
| // indirectly use it through this object passed to their constructor. |
| SurvRateGroup* _short_lived_surv_rate_group; |
| SurvRateGroup* _survivor_surv_rate_group; |
| |
| double _reserve_factor; |
| // This will be set when the heap is expanded |
| // for the first time during initialization. |
| uint _reserve_regions; |
| |
| G1YoungGenSizer* _young_gen_sizer; |
| |
| uint _free_regions_at_end_of_collection; |
| |
| size_t _max_rs_lengths; |
| |
| size_t _rs_lengths_prediction; |
| |
| size_t _pending_cards; |
| |
| // The amount of allocated bytes in old gen during the last mutator and the following |
| // young GC phase. |
| size_t _bytes_allocated_in_old_since_last_gc; |
| |
| G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed; |
| |
| bool should_update_surv_rate_group_predictors() { |
| return collector_state()->in_young_only_phase() && !collector_state()->mark_or_rebuild_in_progress(); |
| } |
| public: |
| const G1Predictions& predictor() const { return _predictor; } |
| const G1Analytics* analytics() const { return const_cast<const G1Analytics*>(_analytics); } |
| |
| G1RemSetTrackingPolicy* remset_tracker() { return &_remset_tracker; } |
| |
| // Add the given number of bytes to the total number of allocated bytes in the old gen. |
| void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; } |
| |
| void set_region_eden(HeapRegion* hr) { |
| hr->set_eden(); |
| hr->install_surv_rate_group(_short_lived_surv_rate_group); |
| } |
| |
| void set_region_survivor(HeapRegion* hr) { |
| assert(hr->is_survivor(), "pre-condition"); |
| hr->install_surv_rate_group(_survivor_surv_rate_group); |
| } |
| |
| void record_max_rs_lengths(size_t rs_lengths) { |
| _max_rs_lengths = rs_lengths; |
| } |
| |
| double predict_base_elapsed_time_ms(size_t pending_cards) const; |
| double predict_base_elapsed_time_ms(size_t pending_cards, |
| size_t scanned_cards) const; |
| size_t predict_bytes_to_copy(HeapRegion* hr) const; |
| double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const; |
| |
| double predict_survivor_regions_evac_time() const; |
| |
| void cset_regions_freed() { |
| bool update = should_update_surv_rate_group_predictors(); |
| |
| _short_lived_surv_rate_group->all_surviving_words_recorded(predictor(), update); |
| _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update); |
| } |
| |
| G1MMUTracker* mmu_tracker() { |
| return _mmu_tracker; |
| } |
| |
| const G1MMUTracker* mmu_tracker() const { |
| return _mmu_tracker; |
| } |
| |
| double max_pause_time_ms() const { |
| return _mmu_tracker->max_gc_time() * 1000.0; |
| } |
| |
| double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const; |
| |
| double predict_yg_surv_rate(int age) const; |
| |
| double accum_yg_surv_rate_pred(int age) const; |
| |
| private: |
| G1CollectionSet* _collection_set; |
| double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const; |
| double other_time_ms(double pause_time_ms) const; |
| |
| double young_other_time_ms() const; |
| double non_young_other_time_ms() const; |
| double constant_other_time_ms(double pause_time_ms) const; |
| |
| G1CollectionSetChooser* cset_chooser() const; |
| |
| // The number of bytes copied during the GC. |
| size_t _bytes_copied_during_gc; |
| |
| // Stash a pointer to the g1 heap. |
| G1CollectedHeap* _g1h; |
| |
| G1GCPhaseTimes* _phase_times; |
| |
| // This set of variables tracks the collector efficiency, in order to |
| // determine whether we should initiate a new marking. |
| double _mark_remark_start_sec; |
| double _mark_cleanup_start_sec; |
| |
| // Updates the internal young list maximum and target lengths. Returns the |
| // unbounded young list target length. |
| uint update_young_list_max_and_target_length(); |
| uint update_young_list_max_and_target_length(size_t rs_lengths); |
| |
| // Update the young list target length either by setting it to the |
| // desired fixed value or by calculating it using G1's pause |
| // prediction model. If no rs_lengths parameter is passed, predict |
| // the RS lengths using the prediction model, otherwise use the |
| // given rs_lengths as the prediction. |
| // Returns the unbounded young list target length. |
| uint update_young_list_target_length(size_t rs_lengths); |
| |
| // Calculate and return the minimum desired young list target |
| // length. This is the minimum desired young list length according |
| // to the user's inputs. |
| uint calculate_young_list_desired_min_length(uint base_min_length) const; |
| |
| // Calculate and return the maximum desired young list target |
| // length. This is the maximum desired young list length according |
| // to the user's inputs. |
| uint calculate_young_list_desired_max_length() const; |
| |
| // Calculate and return the maximum young list target length that |
| // can fit into the pause time goal. The parameters are: rs_lengths |
| // represent the prediction of how large the young RSet lengths will |
| // be, base_min_length is the already existing number of regions in |
| // the young list, min_length and max_length are the desired min and |
| // max young list length according to the user's inputs. |
| uint calculate_young_list_target_length(size_t rs_lengths, |
| uint base_min_length, |
| uint desired_min_length, |
| uint desired_max_length) const; |
| |
| // Result of the bounded_young_list_target_length() method, containing both the |
| // bounded as well as the unbounded young list target lengths in this order. |
| typedef Pair<uint, uint, StackObj> YoungTargetLengths; |
| YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const; |
| |
| void update_rs_lengths_prediction(); |
| void update_rs_lengths_prediction(size_t prediction); |
| |
| // Check whether a given young length (young_length) fits into the |
| // given target pause time and whether the prediction for the amount |
| // of objects to be copied for the given length will fit into the |
| // given free space (expressed by base_free_regions). It is used by |
| // calculate_young_list_target_length(). |
| bool predict_will_fit(uint young_length, double base_time_ms, |
| uint base_free_regions, double target_pause_time_ms) const; |
| |
| public: |
| size_t pending_cards() const { return _pending_cards; } |
| |
| // Calculate the minimum number of old regions we'll add to the CSet |
| // during a mixed GC. |
| uint calc_min_old_cset_length() const; |
| |
| // Calculate the maximum number of old regions we'll add to the CSet |
| // during a mixed GC. |
| uint calc_max_old_cset_length() const; |
| |
| // Returns the given amount of reclaimable bytes (that represents |
| // the amount of reclaimable space still to be collected) as a |
| // percentage of the current heap capacity. |
| double reclaimable_bytes_percent(size_t reclaimable_bytes) const; |
| |
| jlong collection_pause_end_millis() { return _collection_pause_end_millis; } |
| |
| private: |
| void clear_collection_set_candidates(); |
| // Sets up marking if proper conditions are met. |
| void maybe_start_marking(); |
| |
| // The kind of STW pause. |
| enum PauseKind { |
| FullGC, |
| YoungOnlyGC, |
| MixedGC, |
| LastYoungGC, |
| InitialMarkGC, |
| Cleanup, |
| Remark |
| }; |
| |
| // Calculate PauseKind from internal state. |
| PauseKind young_gc_pause_kind() const; |
| // Record the given STW pause with the given start and end times (in s). |
| void record_pause(PauseKind kind, double start, double end); |
| // Indicate that we aborted marking before doing any mixed GCs. |
| void abort_time_to_mixed_tracking(); |
| public: |
| |
| G1Policy(STWGCTimer* gc_timer); |
| |
| virtual ~G1Policy(); |
| |
| static G1Policy* create_policy(STWGCTimer* gc_timer_stw); |
| |
| G1CollectorState* collector_state() const; |
| |
| G1GCPhaseTimes* phase_times() const { return _phase_times; } |
| |
| // Check the current value of the young list RSet lengths and |
| // compare it against the last prediction. If the current value is |
| // higher, recalculate the young list target length prediction. |
| void revise_young_list_target_length_if_necessary(size_t rs_lengths); |
| |
| // This should be called after the heap is resized. |
| void record_new_heap_size(uint new_number_of_regions); |
| |
| virtual void init(G1CollectedHeap* g1h, G1CollectionSet* collection_set); |
| |
| void note_gc_start(); |
| |
| bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0); |
| |
| bool about_to_start_mixed_phase() const; |
| |
| // Record the start and end of an evacuation pause. |
| void record_collection_pause_start(double start_time_sec); |
| virtual void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc); |
| |
| // Record the start and end of a full collection. |
| void record_full_collection_start(); |
| virtual void record_full_collection_end(); |
| |
| // Must currently be called while the world is stopped. |
| void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms); |
| |
| // Record start and end of remark. |
| void record_concurrent_mark_remark_start(); |
| void record_concurrent_mark_remark_end(); |
| |
| // Record start, end, and completion of cleanup. |
| void record_concurrent_mark_cleanup_start(); |
| void record_concurrent_mark_cleanup_end(); |
| |
| void print_phases(); |
| |
| // Record how much space we copied during a GC. This is typically |
| // called when a GC alloc region is being retired. |
| void record_bytes_copied_during_gc(size_t bytes) { |
| _bytes_copied_during_gc += bytes; |
| } |
| |
| // The amount of space we copied during a GC. |
| size_t bytes_copied_during_gc() const { |
| return _bytes_copied_during_gc; |
| } |
| |
| bool next_gc_should_be_mixed(const char* true_action_str, |
| const char* false_action_str) const; |
| |
| // Calculate and return the number of initial and optional old gen regions from |
| // the given collection set candidates and the remaining time. |
| void calculate_old_collection_set_regions(G1CollectionSetCandidates* candidates, |
| double time_remaining_ms, |
| uint& num_initial_regions, |
| uint& num_optional_regions); |
| |
| // Calculate the number of optional regions from the given collection set candidates, |
| // the remaining time and the maximum number of these regions and return the number |
| // of actually selected regions in num_optional_regions. |
| void calculate_optional_collection_set_regions(G1CollectionSetCandidates* candidates, |
| uint const max_optional_regions, |
| double time_remaining_ms, |
| uint& num_optional_regions); |
| |
| private: |
| // Set the state to start a concurrent marking cycle and clear |
| // _initiate_conc_mark_if_possible because it has now been |
| // acted on. |
| void initiate_conc_mark(); |
| |
| public: |
| // This sets the initiate_conc_mark_if_possible() flag to start a |
| // new cycle, as long as we are not already in one. It's best if it |
| // is called during a safepoint when the test whether a cycle is in |
| // progress or not is stable. |
| bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause); |
| |
| // This is called at the very beginning of an evacuation pause (it |
| // has to be the first thing that the pause does). If |
| // initiate_conc_mark_if_possible() is true, and the concurrent |
| // marking thread has completed its work during the previous cycle, |
| // it will set in_initial_mark_gc() to so that the pause does |
| // the initial-mark work and start a marking cycle. |
| void decide_on_conc_mark_initiation(); |
| |
| void finished_recalculating_age_indexes(bool is_survivors) { |
| if (is_survivors) { |
| _survivor_surv_rate_group->finished_recalculating_age_indexes(); |
| } else { |
| _short_lived_surv_rate_group->finished_recalculating_age_indexes(); |
| } |
| } |
| |
| size_t young_list_target_length() const { return _young_list_target_length; } |
| |
| bool should_allocate_mutator_region() const; |
| |
| bool can_expand_young_list() const; |
| |
| uint young_list_max_length() const { |
| return _young_list_max_length; |
| } |
| |
| bool use_adaptive_young_list_length() const; |
| |
| void transfer_survivors_to_cset(const G1SurvivorRegions* survivors); |
| |
| private: |
| // |
| // Survivor regions policy. |
| // |
| |
| // Current tenuring threshold, set to 0 if the collector reaches the |
| // maximum amount of survivors regions. |
| uint _tenuring_threshold; |
| |
| // The limit on the number of regions allocated for survivors. |
| uint _max_survivor_regions; |
| |
| AgeTable _survivors_age_table; |
| |
| size_t desired_survivor_size(uint max_regions) const; |
| |
| // Fraction used when predicting how many optional regions to include in |
| // the CSet. This fraction of the available time is used for optional regions, |
| // the rest is used to add old regions to the normal CSet. |
| double optional_prediction_fraction() { return 0.2; } |
| |
| public: |
| // Fraction used when evacuating the optional regions. This fraction of the |
| // remaining time is used to choose what regions to include in the evacuation. |
| double optional_evacuation_fraction() { return 0.75; } |
| |
| uint tenuring_threshold() const { return _tenuring_threshold; } |
| |
| uint max_survivor_regions() { |
| return _max_survivor_regions; |
| } |
| |
| void note_start_adding_survivor_regions() { |
| _survivor_surv_rate_group->start_adding_regions(); |
| } |
| |
| void note_stop_adding_survivor_regions() { |
| _survivor_surv_rate_group->stop_adding_regions(); |
| } |
| |
| void record_age_table(AgeTable* age_table) { |
| _survivors_age_table.merge(age_table); |
| } |
| |
| void print_age_table(); |
| |
| void update_max_gc_locker_expansion(); |
| |
| void update_survivors_policy(); |
| |
| virtual bool force_upgrade_to_full() { |
| return false; |
| } |
| }; |
| |
| #endif // SHARE_GC_G1_G1POLICY_HPP |