--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/g1CollectorPolicy.hpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,945 @@
+/*
+ * Copyright (c) 2001, 2015, 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_G1_G1COLLECTORPOLICY_HPP
+#define SHARE_VM_GC_G1_G1COLLECTORPOLICY_HPP
+
+#include "gc/g1/collectionSetChooser.hpp"
+#include "gc/g1/g1Allocator.hpp"
+#include "gc/g1/g1MMUTracker.hpp"
+#include "gc/shared/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;
+
+// TraceYoungGenTime collects data on _both_ young and mixed evacuation pauses
+// (the latter may contain non-young regions - i.e. regions that are
+// technically in old) while TraceOldGenTime collects data about full GCs.
+class TraceYoungGenTimeData : 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:
+ TraceYoungGenTimeData() : _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 TraceOldGenTimeData : 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
+// every time 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;
+
+ TraceYoungGenTimeData _trace_young_gen_time_data;
+ TraceOldGenTimeData _trace_old_gen_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 periodically samples the young
+ // region RSets and needs to update _inc_cset_recorded_rs_lengths as
+ // the RSets grow. Instead of having to synchronize 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 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);
+
+ // Calculate and return chunk size (in number of regions) for parallel
+ // concurrent mark cleanup.
+ uint calculate_parallel_work_chunk_size(uint n_workers, uint n_regions);
+
+ // 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(uint n_workers);
+ 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(size_t bytes_before);
+ 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.
+ virtual 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();
+
+ bool can_expand_young_list();
+
+ 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; }
+
+ static const uint REGIONS_UNLIMITED = (uint) -1;
+
+ uint max_regions(InCSetState dest) {
+ switch (dest.value()) {
+ case InCSetState::Young:
+ return _max_survivor_regions;
+ case InCSetState::Old:
+ return REGIONS_UNLIMITED;
+ default:
+ assert(false, err_msg("Unknown dest state: " CSETSTATE_FORMAT, dest.value()));
+ break;
+ }
+ // keep some compilers happy
+ return 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_G1_G1COLLECTORPOLICY_HPP