--- a/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.hpp	Fri Aug 16 16:50:17 2019 +0200
+++ b/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.hpp	Fri Aug 16 18:06:51 2019 +0000
@@ -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;