Java example source code file (g1CollectorPolicy.hpp)
The g1CollectorPolicy.hpp Java example source code
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#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_young();
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_young() && 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
}
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
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