--- a/hotspot/src/share/vm/gc/g1/g1CollectorPolicy.hpp	Thu Dec 10 13:38:18 2015 -0500
+++ b/hotspot/src/share/vm/gc/g1/g1CollectorPolicy.hpp	Thu Dec 10 18:55:58 2015 +0000
@@ -201,6 +201,11 @@
   TruncatedSeq* _concurrent_mark_remark_times_ms;
   TruncatedSeq* _concurrent_mark_cleanup_times_ms;
 
+  // Ratio check data for determining if heap growth is necessary.
+  uint _ratio_over_threshold_count;
+  double _ratio_over_threshold_sum;
+  uint _pauses_since_start;
+
   TraceYoungGenTimeData _trace_young_gen_time_data;
   TraceOldGenTimeData   _trace_old_gen_time_data;
 
@@ -224,7 +229,11 @@
 
   enum PredictionConstants {
     TruncatedSeqLength = 10,
-    NumPrevPausesForHeuristics = 10
+    NumPrevPausesForHeuristics = 10,
+    // MinOverThresholdForGrowth must be less than NumPrevPausesForHeuristics,
+    // representing the minimum number of pause time ratios that exceed
+    // GCTimeRatio before a heap expansion will be triggered.
+    MinOverThresholdForGrowth = 4
   };
 
   TruncatedSeq* _alloc_rate_ms_seq;
@@ -483,8 +492,10 @@
 
   G1GCPhaseTimes* _phase_times;
 
-  // The ratio of gc time to elapsed time, computed over recent pauses.
+  // The ratio of gc time to elapsed time, computed over recent pauses,
+  // and the ratio for just the last pause.
   double _recent_avg_pause_time_ratio;
+  double _last_pause_time_ratio;
 
   double recent_avg_pause_time_ratio() const {
     return _recent_avg_pause_time_ratio;
@@ -760,7 +771,10 @@
 
   // 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() const;
+  virtual size_t expansion_amount();
+
+  // Clear ratio tracking data used by expansion_amount().
+  void clear_ratio_check_data();
 
   // Print tracing information.
   void print_tracing_info() const;