8138750: Remove dead code in survivor rate group

Reviewed-by: mgerdin, tbenson

hotspot/src/share/vm/gc/g1/g1CollectorPolicy.hpp

@@ -343,11 +343,15 @@ public:
 
   double predict_survivor_regions_evac_time() const;
 
+  bool should_update_surv_rate_group_predictors() {
+    return collector_state()->last_young_gc() && !collector_state()->in_marking_window();
+  }
+
   void cset_regions_freed() {
-    bool propagate = collector_state()->should_propagate();
+    bool update = should_update_surv_rate_group_predictors();
-    _short_lived_surv_rate_group->all_surviving_words_recorded(propagate);
+
-    _survivor_surv_rate_group->all_surviving_words_recorded(propagate);
+    _short_lived_surv_rate_group->all_surviving_words_recorded(update);
-    // also call it on any more surv rate groups
+    _survivor_surv_rate_group->all_surviving_words_recorded(update);
   }
 
   G1MMUTracker* mmu_tracker() {

hotspot/src/share/vm/gc/g1/g1CollectorState.hpp

@@ -121,10 +121,6 @@ class G1CollectorState VALUE_OBJ_CLASS_SPEC {
     return (_in_marking_window && !_in_marking_window_im);
   }
 
-  bool should_propagate() const { // XXX should have a more suitable state name or abstraction for this
-    return (_last_young_gc && !_in_marking_window);
-  }
-
   G1YCType yc_type() const {
     if (during_initial_mark_pause()) {
       return InitialMark;

hotspot/src/share/vm/gc/g1/survRateGroup.cpp

@@ -59,7 +59,6 @@ double SurvRateGroup::get_new_prediction(TruncatedSeq const* seq) const {
 void SurvRateGroup::reset() {
   _all_regions_allocated = 0;
   _setup_seq_num         = 0;
-  _accum_surv_rate       = 0.0;
   _last_pred             = 0.0;
   // the following will set up the arrays with length 1
   _region_num            = 1;
@@ -83,7 +82,6 @@ void SurvRateGroup::reset() {
 void SurvRateGroup::start_adding_regions() {
   _setup_seq_num   = _stats_arrays_length;
   _region_num      = 0;
-  _accum_surv_rate = 0.0;
 }
 
 void SurvRateGroup::stop_adding_regions() {
@@ -121,25 +119,7 @@ void SurvRateGroup::stop_adding_regions() {
   }
 }
 
-double SurvRateGroup::accum_surv_rate(size_t adjustment) {
-  // we might relax this one in the future...
-  guarantee( adjustment == 0 || adjustment == 1, "pre-condition" );
-
-  double ret = _accum_surv_rate;
-  if (adjustment > 0) {
-    TruncatedSeq* seq = get_seq(_region_num+1);
-    double surv_rate = get_new_prediction(seq);
-    ret += surv_rate;
-  }
-
-  return ret;
-}
-
 int SurvRateGroup::next_age_index() {
-  TruncatedSeq* seq = get_seq(_region_num);
-  double surv_rate = get_new_prediction(seq);
-  _accum_surv_rate += surv_rate;
-
   ++_region_num;
   return (int) ++_all_regions_allocated;
 }
@@ -160,8 +140,8 @@ void SurvRateGroup::record_surviving_words(int age_in_group, size_t surv_words)
   }
 }
 
-void SurvRateGroup::all_surviving_words_recorded(bool propagate) {
+void SurvRateGroup::all_surviving_words_recorded(bool update_predictors) {
-  if (propagate && _region_num > 0) { // conservative
+  if (update_predictors && _region_num > 0) { // conservative
     double surv_rate = _surv_rate_pred[_region_num-1]->last();
     for (size_t i = _region_num; i < _stats_arrays_length; ++i) {
       guarantee( _surv_rate[i] <= 0.00001,

hotspot/src/share/vm/gc/g1/survRateGroup.hpp

@@ -41,7 +41,6 @@ private:
   double* _surv_rate;
   double* _accum_surv_rate_pred;
   double  _last_pred;
-  double  _accum_surv_rate;
   TruncatedSeq** _surv_rate_pred;
   NumberSeq**    _summary_surv_rates;
   size_t         _summary_surv_rates_len;
@@ -59,7 +58,7 @@ public:
   void start_adding_regions();
   void stop_adding_regions();
   void record_surviving_words(int age_in_group, size_t surv_words);
-  void all_surviving_words_recorded(bool propagate);
+  void all_surviving_words_recorded(bool update_predictors);
   const char* name() { return _name; }
 
   size_t region_num() { return _region_num; }
@@ -73,8 +72,6 @@ public:
     }
   }
 
-  double accum_surv_rate(size_t adjustment);
-
   TruncatedSeq* get_seq(size_t age) const {
     if (age >= _setup_seq_num) {
       guarantee( _setup_seq_num > 0, "invariant" );