--- a/src/hotspot/share/gc/cms/cmsHeap.cpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/cms/cmsHeap.cpp	Wed Jul 03 14:33:40 2019 +0000
@@ -62,7 +62,7 @@
   }
 
   size_t used_in_bytes() {
-    return _space->used_stable();
+    return _space->used();
   }
 };
 

--- a/src/hotspot/share/gc/cms/compactibleFreeListSpace.cpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/cms/compactibleFreeListSpace.cpp	Wed Jul 03 14:33:40 2019 +0000
@@ -372,8 +372,6 @@
     )
   }
   _dictionary->set_par_lock(&_parDictionaryAllocLock);
-
-  _used_stable = 0;
 }
 
 // Like CompactibleSpace forward() but always calls cross_threshold() to
@@ -579,14 +577,6 @@
   return capacity() - free();
 }
 
-size_t CompactibleFreeListSpace::used_stable() const {
-  return _used_stable;
-}
-
-void CompactibleFreeListSpace::recalculate_used_stable() {
-  _used_stable = used();
-}
-
 size_t CompactibleFreeListSpace::free() const {
   // "MT-safe, but not MT-precise"(TM), if you will: i.e.
   // if you do this while the structures are in flux you
@@ -1384,9 +1374,6 @@
     debug_only(fc->mangleAllocated(size));
   }
 
-  // After allocation, recalculate used space and update used_stable
-  recalculate_used_stable();
-
   return res;
 }
 

--- a/src/hotspot/share/gc/cms/compactibleFreeListSpace.hpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/cms/compactibleFreeListSpace.hpp	Wed Jul 03 14:33:40 2019 +0000
@@ -192,9 +192,6 @@
   // Used to keep track of limit of sweep for the space
   HeapWord* _sweep_limit;
 
-  // Stable value of used().
-  size_t _used_stable;
-
   // Used to make the young collector update the mod union table
   MemRegionClosure* _preconsumptionDirtyCardClosure;
 
@@ -415,17 +412,6 @@
   // which overestimates the region by returning the entire
   // committed region (this is safe, but inefficient).
 
-  // Returns monotonically increasing stable used space bytes for CMS.
-  // This is required for jstat and other memory monitoring tools
-  // that might otherwise see inconsistent used space values during a garbage
-  // collection, promotion or allocation into compactibleFreeListSpace.
-  // The value returned by this function might be smaller than the
-  // actual value.
-  size_t used_stable() const;
-  // Recalculate and cache the current stable used() value. Only to be called
-  // in places where we can be sure that the result is stable.
-  void recalculate_used_stable();
-
   // Returns a subregion of the space containing all the objects in
   // the space.
   MemRegion used_region() const {

--- a/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.cpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.cpp	Wed Jul 03 14:33:40 2019 +0000
@@ -692,10 +692,6 @@
   return _cmsSpace->max_alloc_in_words() * HeapWordSize;
 }
 
-size_t ConcurrentMarkSweepGeneration::used_stable() const {
-  return cmsSpace()->used_stable();
-}
-
 size_t ConcurrentMarkSweepGeneration::max_available() const {
   return free() + _virtual_space.uncommitted_size();
 }
@@ -1527,8 +1523,6 @@
   FreelistLocker z(this);
   MetaspaceGC::compute_new_size();
   _cmsGen->compute_new_size_free_list();
-  // recalculate CMS used space after CMS collection
-  _cmsGen->cmsSpace()->recalculate_used_stable();
 }
 
 // A work method used by the foreground collector to do
@@ -2057,7 +2051,6 @@
 
   _capacity_at_prologue = capacity();
   _used_at_prologue = used();
-  _cmsSpace->recalculate_used_stable();
 
   // We enable promotion tracking so that card-scanning can recognize
   // which objects have been promoted during this GC and skip them.
@@ -2130,7 +2123,6 @@
   _eden_chunk_index = 0;
 
   size_t cms_used   = _cmsGen->cmsSpace()->used();
-  _cmsGen->cmsSpace()->recalculate_used_stable();
 
   // update performance counters - this uses a special version of
   // update_counters() that allows the utilization to be passed as a
@@ -2824,8 +2816,6 @@
     rp->enable_discovery();
     _collectorState = Marking;
   }
-
-  _cmsGen->cmsSpace()->recalculate_used_stable();
 }
 
 void CMSCollector::checkpointRootsInitialWork() {
@@ -4187,7 +4177,6 @@
     MutexLocker y(bitMapLock(),
                   Mutex::_no_safepoint_check_flag);
     checkpointRootsFinalWork();
-    _cmsGen->cmsSpace()->recalculate_used_stable();
   }
   verify_work_stacks_empty();
   verify_overflow_empty();
@@ -5347,14 +5336,9 @@
     // further below.
     {
       CMSTokenSyncWithLocks ts(true, _cmsGen->freelistLock());
-
       // Update heap occupancy information which is used as
       // input to soft ref clearing policy at the next gc.
       Universe::update_heap_info_at_gc();
-
-      // recalculate CMS used space after CMS collection
-      _cmsGen->cmsSpace()->recalculate_used_stable();
-
       _collectorState = Resizing;
     }
   }
@@ -5443,7 +5427,6 @@
     // Gather statistics on the young generation collection.
     collector()->stats().record_gc0_end(used());
   }
-  _cmsSpace->recalculate_used_stable();
 }
 
 void CMSCollector::sweepWork(ConcurrentMarkSweepGeneration* old_gen) {

--- a/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.hpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/cms/concurrentMarkSweepGeneration.hpp	Wed Jul 03 14:33:40 2019 +0000
@@ -1112,7 +1112,6 @@
   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;

--- a/src/hotspot/share/gc/cms/gSpaceCounters.hpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/cms/gSpaceCounters.hpp	Wed Jul 03 14:33:40 2019 +0000
@@ -59,7 +59,7 @@
   }
 
   inline void update_used() {
-    _used->set_value(_gen->used_stable());
+    _used->set_value(_gen->used());
   }
 
   // special version of update_used() to allow the used value to be
@@ -103,7 +103,7 @@
     GenerationUsedHelper(Generation* g) : _gen(g) { }
 
     inline jlong take_sample() {
-      return _gen->used_stable();
+      return _gen->used();
     }
 };
 

--- a/src/hotspot/share/gc/shared/generation.cpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/shared/generation.cpp	Wed Jul 03 14:33:40 2019 +0000
@@ -68,12 +68,6 @@
   return gch->old_gen_spec()->init_size();
 }
 
-// This is for CMS. It returns stable monotonic used space size.
-// Remove this when CMS is removed.
-size_t Generation::used_stable() const {
-  return used();
-}
-
 size_t Generation::max_capacity() const {
   return reserved().byte_size();
 }

--- a/src/hotspot/share/gc/shared/generation.hpp	Tue Jul 02 13:45:08 2019 +0200
+++ b/src/hotspot/share/gc/shared/generation.hpp	Wed Jul 03 14:33:40 2019 +0000
@@ -156,7 +156,6 @@
   virtual size_t capacity() const = 0;  // The maximum number of object bytes the
                                         // generation can currently hold.
   virtual size_t used() const = 0;      // The number of used bytes in the gen.
-  virtual size_t used_stable() const;   // The number of used bytes for memory monitoring tools.
   virtual size_t free() const = 0;      // The number of free bytes in the gen.
 
   // Support for java.lang.Runtime.maxMemory(); see CollectedHeap.