jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp

Fri, 10 Oct 2014 15:51:58 +0200

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7195: c02ec279b062
child 7369: b840813adfcc
permissions: -rw-r--r--

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

 /*
  * Copyright (c) 2001, 2013, 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
  * questions.
  *
  */
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP
 #include "gc_implementation/g1/collectionSetChooser.hpp"
 #include "gc_implementation/g1/g1MMUTracker.hpp"
 #include "memory/collectorPolicy.hpp"
 // A G1CollectorPolicy makes policy decisions that determine the
 // characteristics of the collector.  Examples include:
 //   * choice of collection set.
 //   * when to collect.
 class HeapRegion;
 class CollectionSetChooser;
 class G1GCPhaseTimes;
 // TraceGen0Time collects data on _both_ young and mixed evacuation pauses
 // (the latter may contain non-young regions - i.e. regions that are
 // technically in Gen1) while TraceGen1Time collects data about full GCs.
 class TraceGen0TimeData : public CHeapObj<mtGC> {
  private:
   unsigned  _young_pause_num;
   unsigned  _mixed_pause_num;
   NumberSeq _all_stop_world_times_ms;
   NumberSeq _all_yield_times_ms;
   NumberSeq _total;
   NumberSeq _other;
   NumberSeq _root_region_scan_wait;
   NumberSeq _parallel;
   NumberSeq _ext_root_scan;
   NumberSeq _satb_filtering;
   NumberSeq _update_rs;
   NumberSeq _scan_rs;
   NumberSeq _obj_copy;
   NumberSeq _termination;
   NumberSeq _parallel_other;
   NumberSeq _clear_ct;
   void print_summary(const char* str, const NumberSeq* seq) const;
   void print_summary_sd(const char* str, const NumberSeq* seq) const;
 public:
    TraceGen0TimeData() : _young_pause_num(0), _mixed_pause_num(0) {};
   void record_start_collection(double time_to_stop_the_world_ms);
   void record_yield_time(double yield_time_ms);
   void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times);
   void increment_young_collection_count();
   void increment_mixed_collection_count();
   void print() const;
 };
 class TraceGen1TimeData : public CHeapObj<mtGC> {
  private:
   NumberSeq _all_full_gc_times;
  public:
   void record_full_collection(double full_gc_time_ms);
   void print() const;
 };
 // There are three command line options related to the young gen size:
 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
 // just a short form for NewSize==MaxNewSize). G1 will use its internal
 // heuristics to calculate the actual young gen size, so these options
 // basically only limit the range within which G1 can pick a young gen
 // size. Also, these are general options taking byte sizes. G1 will
 // internally work with a number of regions instead. So, some rounding
 // will occur.
 //
 // If nothing related to the the young gen size is set on the command
 // line we should allow the young gen to be between G1NewSizePercent
 // and G1MaxNewSizePercent of the heap size. This means that every time
 // the heap size changes, the limits for the young gen size will be
 // recalculated.
 //
 // If only -XX:NewSize is set we should use the specified value as the
 // minimum size for young gen. Still using G1MaxNewSizePercent of the
 // heap as maximum.
 //
 // If only -XX:MaxNewSize is set we should use the specified value as the
 // maximum size for young gen. Still using G1NewSizePercent of the heap
 // as minimum.
 //
 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
 // No updates when the heap size changes. There is a special case when
 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
 // different heuristic for calculating the collection set when we do mixed
 // collection.
 //
 // If only -XX:NewRatio is set we should use the specified ratio of the heap
 // as both min and max. This will be interpreted as "fixed" just like the
 // NewSize==MaxNewSize case above. But we will update the min and max
 // everytime the heap size changes.
 //
 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
 class G1YoungGenSizer : public CHeapObj<mtGC> {
 private:
   enum SizerKind {
     SizerDefaults,
     SizerNewSizeOnly,
     SizerMaxNewSizeOnly,
     SizerMaxAndNewSize,
     SizerNewRatio
   };
   SizerKind _sizer_kind;
   uint _min_desired_young_length;
   uint _max_desired_young_length;
   bool _adaptive_size;
   uint calculate_default_min_length(uint new_number_of_heap_regions);
   uint calculate_default_max_length(uint new_number_of_heap_regions);
   // Update the given values for minimum and maximum young gen length in regions
   // given the number of heap regions depending on the kind of sizing algorithm.
   void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length);
 public:
   G1YoungGenSizer();
   // Calculate the maximum length of the young gen given the number of regions
   // depending on the sizing algorithm.
   uint max_young_length(uint number_of_heap_regions);
   void heap_size_changed(uint new_number_of_heap_regions);
   uint min_desired_young_length() {
     return _min_desired_young_length;
   }
   uint max_desired_young_length() {
     return _max_desired_young_length;
   }
   bool adaptive_young_list_length() {
     return _adaptive_size;
   }
 };
 class G1CollectorPolicy: public CollectorPolicy {
 private:
   // either equal to the number of parallel threads, if ParallelGCThreads
   // has been set, or 1 otherwise
   int _parallel_gc_threads;
   // The number of GC threads currently active.
   uintx _no_of_gc_threads;
   enum SomePrivateConstants {
     NumPrevPausesForHeuristics = 10
   };
   G1MMUTracker* _mmu_tracker;
   void initialize_alignments();
   void initialize_flags();
   CollectionSetChooser* _collectionSetChooser;
   double _full_collection_start_sec;
   uint   _cur_collection_pause_used_regions_at_start;
   // These exclude marking times.
   TruncatedSeq* _recent_gc_times_ms;
   TruncatedSeq* _concurrent_mark_remark_times_ms;
   TruncatedSeq* _concurrent_mark_cleanup_times_ms;
   TraceGen0TimeData _trace_gen0_time_data;
   TraceGen1TimeData _trace_gen1_time_data;
   double _stop_world_start;
   // indicates whether we are in young or mixed GC mode
   bool _gcs_are_young;
   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;
   bool                  _last_gc_was_young;
   bool                  _during_marking;
   bool                  _in_marking_window;
   bool                  _in_marking_window_im;
   SurvRateGroup*        _short_lived_surv_rate_group;
   SurvRateGroup*        _survivor_surv_rate_group;
   // add here any more surv rate groups
   double                _gc_overhead_perc;
   double _reserve_factor;
   uint _reserve_regions;
   bool during_marking() {
     return _during_marking;
   }
   enum PredictionConstants {
     TruncatedSeqLength = 10
   };
   TruncatedSeq* _alloc_rate_ms_seq;
   double        _prev_collection_pause_end_ms;
   TruncatedSeq* _rs_length_diff_seq;
   TruncatedSeq* _cost_per_card_ms_seq;
   TruncatedSeq* _young_cards_per_entry_ratio_seq;
   TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
   TruncatedSeq* _cost_per_entry_ms_seq;
   TruncatedSeq* _mixed_cost_per_entry_ms_seq;
   TruncatedSeq* _cost_per_byte_ms_seq;
   TruncatedSeq* _constant_other_time_ms_seq;
   TruncatedSeq* _young_other_cost_per_region_ms_seq;
   TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
   TruncatedSeq* _pending_cards_seq;
   TruncatedSeq* _rs_lengths_seq;
   TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
   G1YoungGenSizer* _young_gen_sizer;
   uint _eden_cset_region_length;
   uint _survivor_cset_region_length;
   uint _old_cset_region_length;
   void init_cset_region_lengths(uint eden_cset_region_length,
                                 uint survivor_cset_region_length);
   uint eden_cset_region_length()     { return _eden_cset_region_length;     }
   uint survivor_cset_region_length() { return _survivor_cset_region_length; }
   uint old_cset_region_length()      { return _old_cset_region_length;      }
   uint _free_regions_at_end_of_collection;
   size_t _recorded_rs_lengths;
   size_t _max_rs_lengths;
   double _sigma;
   size_t _rs_lengths_prediction;
   double sigma() { return _sigma; }
   // A function that prevents us putting too much stock in small sample
   // sets.  Returns a number between 2.0 and 1.0, depending on the number
   // of samples.  5 or more samples yields one; fewer scales linearly from
   // 2.0 at 1 sample to 1.0 at 5.
   double confidence_factor(int samples) {
     if (samples > 4) return 1.0;
     else return  1.0 + sigma() * ((double)(5 - samples))/2.0;
   }
   double get_new_neg_prediction(TruncatedSeq* seq) {
     return seq->davg() - sigma() * seq->dsd();
   }
 #ifndef PRODUCT
   bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
 #endif // PRODUCT
   void adjust_concurrent_refinement(double update_rs_time,
                                     double update_rs_processed_buffers,
                                     double goal_ms);
   uintx no_of_gc_threads() { return _no_of_gc_threads; }
   void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
   double _pause_time_target_ms;
   size_t _pending_cards;
 public:
   // Accessors
   void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
     hr->set_eden();
     hr->install_surv_rate_group(_short_lived_surv_rate_group);
     hr->set_young_index_in_cset(young_index_in_cset);
   }
   void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
     assert(hr->is_survivor(), "pre-condition");
     hr->install_surv_rate_group(_survivor_surv_rate_group);
     hr->set_young_index_in_cset(young_index_in_cset);
   }
 #ifndef PRODUCT
   bool verify_young_ages();
 #endif // PRODUCT
   double get_new_prediction(TruncatedSeq* seq) {
     return MAX2(seq->davg() + sigma() * seq->dsd(),
                 seq->davg() * confidence_factor(seq->num()));
   }
   void record_max_rs_lengths(size_t rs_lengths) {
     _max_rs_lengths = rs_lengths;
   }
   size_t predict_rs_length_diff() {
     return (size_t) get_new_prediction(_rs_length_diff_seq);
   }
   double predict_alloc_rate_ms() {
     return get_new_prediction(_alloc_rate_ms_seq);
   }
   double predict_cost_per_card_ms() {
     return get_new_prediction(_cost_per_card_ms_seq);
   }
   double predict_rs_update_time_ms(size_t pending_cards) {
     return (double) pending_cards * predict_cost_per_card_ms();
   }
   double predict_young_cards_per_entry_ratio() {
     return get_new_prediction(_young_cards_per_entry_ratio_seq);
   }
   double predict_mixed_cards_per_entry_ratio() {
     if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
       return predict_young_cards_per_entry_ratio();
     } else {
       return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
     }
   }
   size_t predict_young_card_num(size_t rs_length) {
     return (size_t) ((double) rs_length *
                      predict_young_cards_per_entry_ratio());
   }
   size_t predict_non_young_card_num(size_t rs_length) {
     return (size_t) ((double) rs_length *
                      predict_mixed_cards_per_entry_ratio());
   }
   double predict_rs_scan_time_ms(size_t card_num) {
     if (gcs_are_young()) {
       return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);
     } else {
       return predict_mixed_rs_scan_time_ms(card_num);
     }
   }
   double predict_mixed_rs_scan_time_ms(size_t card_num) {
     if (_mixed_cost_per_entry_ms_seq->num() < 3) {
       return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);
     } else {
       return (double) (card_num *
                        get_new_prediction(_mixed_cost_per_entry_ms_seq));
     }
   }
   double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) {
     if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
       return (1.1 * (double) bytes_to_copy) *
               get_new_prediction(_cost_per_byte_ms_seq);
     } else {
       return (double) bytes_to_copy *
              get_new_prediction(_cost_per_byte_ms_during_cm_seq);
     }
   }
   double predict_object_copy_time_ms(size_t bytes_to_copy) {
     if (_in_marking_window && !_in_marking_window_im) {
       return predict_object_copy_time_ms_during_cm(bytes_to_copy);
     } else {
       return (double) bytes_to_copy *
               get_new_prediction(_cost_per_byte_ms_seq);
     }
   }
   double predict_constant_other_time_ms() {
     return get_new_prediction(_constant_other_time_ms_seq);
   }
   double predict_young_other_time_ms(size_t young_num) {
     return (double) young_num *
            get_new_prediction(_young_other_cost_per_region_ms_seq);
   }
   double predict_non_young_other_time_ms(size_t non_young_num) {
     return (double) non_young_num *
            get_new_prediction(_non_young_other_cost_per_region_ms_seq);
   }
   double predict_base_elapsed_time_ms(size_t pending_cards);
   double predict_base_elapsed_time_ms(size_t pending_cards,
                                       size_t scanned_cards);
   size_t predict_bytes_to_copy(HeapRegion* hr);
   double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc);
   void set_recorded_rs_lengths(size_t rs_lengths);
   uint cset_region_length()       { return young_cset_region_length() +
                                            old_cset_region_length(); }
   uint young_cset_region_length() { return eden_cset_region_length() +
                                            survivor_cset_region_length(); }
   double predict_survivor_regions_evac_time();
   void cset_regions_freed() {
     bool propagate = _last_gc_was_young && !_in_marking_window;
     _short_lived_surv_rate_group->all_surviving_words_recorded(propagate);
     _survivor_surv_rate_group->all_surviving_words_recorded(propagate);
     // also call it on any more surv rate groups
   }
   G1MMUTracker* mmu_tracker() {
     return _mmu_tracker;
   }
   double max_pause_time_ms() {
     return _mmu_tracker->max_gc_time() * 1000.0;
   }
   double predict_remark_time_ms() {
     return get_new_prediction(_concurrent_mark_remark_times_ms);
   }
   double predict_cleanup_time_ms() {
     return get_new_prediction(_concurrent_mark_cleanup_times_ms);
   }
   // Returns an estimate of the survival rate of the region at yg-age
   // "yg_age".
   double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) {
     TruncatedSeq* seq = surv_rate_group->get_seq(age);
     if (seq->num() == 0)
       gclog_or_tty->print("BARF! age is %d", age);
     guarantee( seq->num() > 0, "invariant" );
     double pred = get_new_prediction(seq);
     if (pred > 1.0)
       pred = 1.0;
     return pred;
   }
   double predict_yg_surv_rate(int age) {
     return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
   }
   double accum_yg_surv_rate_pred(int age) {
     return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
   }
 private:
   // Statistics kept per GC stoppage, pause or full.
   TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
   // Add a new GC of the given duration and end time to the record.
   void update_recent_gc_times(double end_time_sec, double elapsed_ms);
   // The head of the list (via "next_in_collection_set()") representing the
   // current collection set. Set from the incrementally built collection
   // set at the start of the pause.
   HeapRegion* _collection_set;
   // The number of bytes in the collection set before the pause. Set from
   // the incrementally built collection set at the start of an evacuation
   // pause, and incremented in finalize_cset() when adding old regions
   // (if any) to the collection set.
   size_t _collection_set_bytes_used_before;
   // The number of bytes copied during the GC.
   size_t _bytes_copied_during_gc;
   // The associated information that is maintained while the incremental
   // collection set is being built with young regions. Used to populate
   // the recorded info for the evacuation pause.
   enum CSetBuildType {
     Active,             // We are actively building the collection set
     Inactive            // We are not actively building the collection set
   };
   CSetBuildType _inc_cset_build_state;
   // The head of the incrementally built collection set.
   HeapRegion* _inc_cset_head;
   // The tail of the incrementally built collection set.
   HeapRegion* _inc_cset_tail;
   // The number of bytes in the incrementally built collection set.
   // Used to set _collection_set_bytes_used_before at the start of
   // an evacuation pause.
   size_t _inc_cset_bytes_used_before;
   // Used to record the highest end of heap region in collection set
   HeapWord* _inc_cset_max_finger;
   // The RSet lengths recorded for regions in the CSet. It is updated
   // by the thread that adds a new region to the CSet. We assume that
   // only one thread can be allocating a new CSet region (currently,
   // it does so after taking the Heap_lock) hence no need to
   // synchronize updates to this field.
   size_t _inc_cset_recorded_rs_lengths;
   // A concurrent refinement thread periodcially samples the young
   // region RSets and needs to update _inc_cset_recorded_rs_lengths as
   // the RSets grow. Instead of having to syncronize updates to that
   // field we accumulate them in this field and add it to
   // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
   ssize_t _inc_cset_recorded_rs_lengths_diffs;
   // The predicted elapsed time it will take to collect the regions in
   // the CSet. This is updated by the thread that adds a new region to
   // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
   // MT-safety assumptions.
   double _inc_cset_predicted_elapsed_time_ms;
   // See the comment for _inc_cset_recorded_rs_lengths_diffs.
   double _inc_cset_predicted_elapsed_time_ms_diffs;
   // Stash a pointer to the g1 heap.
   G1CollectedHeap* _g1;
   G1GCPhaseTimes* _phase_times;
   // The ratio of gc time to elapsed time, computed over recent pauses.
   double _recent_avg_pause_time_ratio;
   double recent_avg_pause_time_ratio() {
     return _recent_avg_pause_time_ratio;
   }
   // At the end of a pause we check the heap occupancy and we decide
   // whether we will start a marking cycle during the next pause. If
   // we decide that we want to do that, we will set this parameter to
   // true. So, this parameter will stay true between the end of a
   // pause and the beginning of a subsequent pause (not necessarily
   // the next one, see the comments on the next field) when we decide
   // that we will indeed start a marking cycle and do the initial-mark
   // work.
   volatile bool _initiate_conc_mark_if_possible;
   // If initiate_conc_mark_if_possible() is set at the beginning of a
   // pause, it is a suggestion that the pause should start a marking
   // cycle by doing the initial-mark work. However, it is possible
   // that the concurrent marking thread is still finishing up the
   // previous marking cycle (e.g., clearing the next marking
   // bitmap). If that is the case we cannot start a new cycle and
   // we'll have to wait for the concurrent marking thread to finish
   // what it is doing. In this case we will postpone the marking cycle
   // initiation decision for the next pause. When we eventually decide
   // to start a cycle, we will set _during_initial_mark_pause which
   // will stay true until the end of the initial-mark pause and it's
   // the condition that indicates that a pause is doing the
   // initial-mark work.
   volatile bool _during_initial_mark_pause;
   bool _last_young_gc;
   // This set of variables tracks the collector efficiency, in order to
   // determine whether we should initiate a new marking.
   double _cur_mark_stop_world_time_ms;
   double _mark_remark_start_sec;
   double _mark_cleanup_start_sec;
   // 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.
   void update_young_list_target_length(size_t rs_lengths = (size_t) -1);
   // 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);
   // 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();
   // 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 alreay 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);
   // 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);
   // Calculate the minimum number of old regions we'll add to the CSet
   // during a mixed GC.
   uint calc_min_old_cset_length();
   // Calculate the maximum number of old regions we'll add to the CSet
   // during a mixed GC.
   uint calc_max_old_cset_length();
   // Returns the given amount of uncollected reclaimable space
   // as a percentage of the current heap capacity.
   double reclaimable_bytes_perc(size_t reclaimable_bytes);
 public:
   G1CollectorPolicy();
   virtual G1CollectorPolicy* as_g1_policy() { return this; }
   virtual CollectorPolicy::Name kind() {
     return CollectorPolicy::G1CollectorPolicyKind;
   }
   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();
   // This should be called after the heap is resized.
   void record_new_heap_size(uint new_number_of_regions);
   void init();
   // Create jstat counters for the policy.
   virtual void initialize_gc_policy_counters();
   virtual HeapWord* mem_allocate_work(size_t size,
                                       bool is_tlab,
                                       bool* gc_overhead_limit_was_exceeded);
   // This method controls how a collector handles one or more
   // of its generations being fully allocated.
   virtual HeapWord* satisfy_failed_allocation(size_t size,
                                               bool is_tlab);
   BarrierSet::Name barrier_set_name() { return BarrierSet::G1SATBCTLogging; }
   bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
   // Record the start and end of an evacuation pause.
   void record_collection_pause_start(double start_time_sec);
   void record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info);
   // Record the start and end of a full collection.
   void record_full_collection_start();
   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(int no_of_gc_threads);
   void record_concurrent_mark_cleanup_completed();
   // Records the information about the heap size for reporting in
   // print_detailed_heap_transition
   void record_heap_size_info_at_start(bool full);
   // Print heap sizing transition (with less and more detail).
   void print_heap_transition();
   void print_detailed_heap_transition(bool full = false);
   void record_stop_world_start();
   void record_concurrent_pause();
   // 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() {
     return _bytes_copied_during_gc;
   }
   // Determine whether there are candidate regions so that the
   // next GC should be mixed. The two action strings are used
   // in the ergo output when the method returns true or false.
   bool next_gc_should_be_mixed(const char* true_action_str,
                                const char* false_action_str);
   // Choose a new collection set.  Marks the chosen regions as being
   // "in_collection_set", and links them together.  The head and number of
   // the collection set are available via access methods.
   void finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info);
   // The head of the list (via "next_in_collection_set()") representing the
   // current collection set.
   HeapRegion* collection_set() { return _collection_set; }
   void clear_collection_set() { _collection_set = NULL; }
   // Add old region "hr" to the CSet.
   void add_old_region_to_cset(HeapRegion* hr);
   // Incremental CSet Support
   // The head of the incrementally built collection set.
   HeapRegion* inc_cset_head() { return _inc_cset_head; }
   // The tail of the incrementally built collection set.
   HeapRegion* inc_set_tail() { return _inc_cset_tail; }
   // Initialize incremental collection set info.
   void start_incremental_cset_building();
   // Perform any final calculations on the incremental CSet fields
   // before we can use them.
   void finalize_incremental_cset_building();
   void clear_incremental_cset() {
     _inc_cset_head = NULL;
     _inc_cset_tail = NULL;
   }
   // Stop adding regions to the incremental collection set
   void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
   // Add information about hr to the aggregated information for the
   // incrementally built collection set.
   void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
   // Update information about hr in the aggregated information for
   // the incrementally built collection set.
   void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
 private:
   // Update the incremental cset information when adding a region
   // (should not be called directly).
   void add_region_to_incremental_cset_common(HeapRegion* hr);
 public:
   // Add hr to the LHS of the incremental collection set.
   void add_region_to_incremental_cset_lhs(HeapRegion* hr);
   // Add hr to the RHS of the incremental collection set.
   void add_region_to_incremental_cset_rhs(HeapRegion* hr);
 #ifndef PRODUCT
   void print_collection_set(HeapRegion* list_head, outputStream* st);
 #endif // !PRODUCT
   bool initiate_conc_mark_if_possible()       { return _initiate_conc_mark_if_possible;  }
   void set_initiate_conc_mark_if_possible()   { _initiate_conc_mark_if_possible = true;  }
   void clear_initiate_conc_mark_if_possible() { _initiate_conc_mark_if_possible = false; }
   bool during_initial_mark_pause()      { return _during_initial_mark_pause;  }
   void set_during_initial_mark_pause()  { _during_initial_mark_pause = true;  }
   void clear_during_initial_mark_pause(){ _during_initial_mark_pause = false; }
   // 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 during_initial_mark_pause() to so that the pause does
   // the initial-mark work and start a marking cycle.
   void decide_on_conc_mark_initiation();
   // If an expansion would be appropriate, because recent GC overhead had
   // exceeded the desired limit, return an amount to expand by.
   size_t expansion_amount();
   // Print tracing information.
   void print_tracing_info() const;
   // Print stats on young survival ratio
   void print_yg_surv_rate_info() const;
   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();
     }
     // do that for any other surv rate groups
   }
   size_t young_list_target_length() const { return _young_list_target_length; }
   bool is_young_list_full() {
     uint young_list_length = _g1->young_list()->length();
     uint young_list_target_length = _young_list_target_length;
     return young_list_length >= young_list_target_length;
   }
   bool can_expand_young_list() {
     uint young_list_length = _g1->young_list()->length();
     uint young_list_max_length = _young_list_max_length;
     return young_list_length < young_list_max_length;
   }
   uint young_list_max_length() {
     return _young_list_max_length;
   }
   bool gcs_are_young() {
     return _gcs_are_young;
   }
   void set_gcs_are_young(bool gcs_are_young) {
     _gcs_are_young = gcs_are_young;
   }
   bool adaptive_young_list_length() {
     return _young_gen_sizer->adaptive_young_list_length();
   }
 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;
   // For reporting purposes.
   // The value of _heap_bytes_before_gc is also used to calculate
   // the cost of copying.
   size_t _eden_used_bytes_before_gc;         // Eden occupancy before GC
   size_t _survivor_used_bytes_before_gc;     // Survivor occupancy before GC
   size_t _heap_used_bytes_before_gc;         // Heap occupancy before GC
   size_t _metaspace_used_bytes_before_gc;    // Metaspace occupancy before GC
   size_t _eden_capacity_bytes_before_gc;     // Eden capacity before GC
   size_t _heap_capacity_bytes_before_gc;     // Heap capacity before GC
   // The amount of survivor regions after a collection.
   uint _recorded_survivor_regions;
   // List of survivor regions.
   HeapRegion* _recorded_survivor_head;
   HeapRegion* _recorded_survivor_tail;
   ageTable _survivors_age_table;
 public:
   uint tenuring_threshold() const { return _tenuring_threshold; }
   inline GCAllocPurpose
     evacuation_destination(HeapRegion* src_region, uint age, size_t word_sz) {
       if (age < _tenuring_threshold && src_region->is_young()) {
         return GCAllocForSurvived;
       } else {
         return GCAllocForTenured;
       }
   }
   inline bool track_object_age(GCAllocPurpose purpose) {
     return purpose == GCAllocForSurvived;
   }
   static const uint REGIONS_UNLIMITED = (uint) -1;
   uint max_regions(int purpose);
   // The limit on regions for a particular purpose is reached.
   void note_alloc_region_limit_reached(int purpose) {
     if (purpose == GCAllocForSurvived) {
       _tenuring_threshold = 0;
     }
   }
   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_survivor_regions(uint regions,
                                HeapRegion* head,
                                HeapRegion* tail) {
     _recorded_survivor_regions = regions;
     _recorded_survivor_head    = head;
     _recorded_survivor_tail    = tail;
   }
   uint recorded_survivor_regions() {
     return _recorded_survivor_regions;
   }
   void record_thread_age_table(ageTable* age_table) {
     _survivors_age_table.merge_par(age_table);
   }
   void update_max_gc_locker_expansion();
   // Calculates survivor space parameters.
   void update_survivors_policy();
   virtual void post_heap_initialize();
 };
 // This should move to some place more general...
 // If we have "n" measurements, and we've kept track of their "sum" and the
 // "sum_of_squares" of the measurements, this returns the variance of the
 // sequence.
 inline double variance(int n, double sum_of_squares, double sum) {
   double n_d = (double)n;
   double avg = sum/n_d;
   return (sum_of_squares - 2.0 * avg * sum + n_d * avg * avg) / n_d;
 }
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp