--- old/src/hotspot/share/gc/g1/g1Policy.hpp	2019-03-13 14:03:12.000325895 +0100
+++ new/src/hotspot/share/gc/g1/g1Policy.hpp	2019-03-13 14:03:11.789320165 +0100
@@ -44,6 +44,7 @@
 
 class HeapRegion;
 class G1CollectionSet;
+class G1CollectionSetCandidates;
 class G1CollectionSetChooser;
 class G1IHOPControl;
 class G1Analytics;
@@ -344,7 +345,24 @@
   bool next_gc_should_be_mixed(const char* true_action_str,
                                const char* false_action_str) const;
 
-  uint finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor);
+  // Select and return the number of initial and optional old gen regions from
+  // the given collection set candidates and the remaining time. Num_expensive_regions
+  // returns the number of regions taken within the initial region count because of
+  // the minimum old gen region requirement.
+  void select_old_collection_set_regions(G1CollectionSetCandidates* candidates,
+                                         double time_remaining_ms,
+                                         uint& num_expensive_regions,
+                                         uint& num_initial_regions,
+                                         uint& num_optional_regions);
+
+  // Select the number of optional regions from the given collection set candidates,
+  // the remaining time and the maximum number of these regions and return in
+  // num_optional_regions.
+  void select_optional_collection_set_regions(G1CollectionSetCandidates* candidates,
+                                              uint const max_optional_regions,
+                                              double time_remaining_ms,
+                                              uint& num_optional_regions);
+
 private:
   // Set the state to start a concurrent marking cycle and clear
   // _initiate_conc_mark_if_possible because it has now been
@@ -403,11 +421,13 @@
   AgeTable _survivors_age_table;
 
   size_t desired_survivor_size(uint max_regions) const;
-public:
+
   // Fraction used when predicting how many optional regions to include in
   // the CSet. This fraction of the available time is used for optional regions,
   // the rest is used to add old regions to the normal CSet.
   double optional_prediction_fraction() { return 0.2; }
+
+public:
   // Fraction used when evacuating the optional regions. This fraction of the
   // remaining time is used to choose what regions to include in the evacuation.
   double optional_evacuation_fraction() { return 0.75; }