--- old/src/hotspot/share/gc/g1/g1HeapSizingPolicy.hpp	2020-02-25 15:41:44.400057775 +0800
+++ new/src/hotspot/share/gc/g1/g1HeapSizingPolicy.hpp	2020-02-25 15:41:44.402057847 +0800
@@ -45,15 +45,19 @@
   double _ratio_over_threshold_sum;
   uint _pauses_since_start;
 
-
-protected:
   G1HeapSizingPolicy(const G1CollectedHeap* g1h, const G1Analytics* analytics);
+
 public:
 
   // 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();
+  size_t expansion_amount_after_young_collection();
+
+  size_t shrink_amount_at_last_mixed_gc(size_t desired_bytes_after_concurrent_mark);
+  size_t shrink_amount_after_concurrent_mark();
 
+  // Calculate the target capacity based on used bytes and free ratio
+  size_t target_heap_capacity(size_t used_bytes, uintx free_ratio) const;
   // Clear ratio tracking data used by expansion_amount().
   void clear_ratio_check_data();