--- old/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.hpp	Fri Jun 21 17:34:10 2019
+++ new/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.hpp	Fri Jun 21 17:34:09 2019
@@ -1112,6 +1112,7 @@
   double occupancy() const { return ((double)used())/((double)capacity()); }
   size_t contiguous_available() const;
   size_t unsafe_max_alloc_nogc() const;
+  size_t used_stable() const;
 
   // over-rides
   MemRegion used_region_at_save_marks() const;