--- a/src/hotspot/share/gc/z/zServiceability.cpp	Thu Aug 09 11:24:30 2018 +0200
+++ b/src/hotspot/share/gc/z/zServiceability.cpp	Thu Aug 09 11:24:30 2018 +0200
@@ -30,29 +30,24 @@
 #include "memory/metaspaceCounters.hpp"
 #include "runtime/perfData.hpp"
 
-class ZOldGenerationCounters : public GenerationCounters {
+class ZGenerationCounters : public GenerationCounters {
 public:
-  ZOldGenerationCounters(const char* name, size_t min_capacity, size_t max_capacity) :
-      // The "1, 1" parameters are for the n-th generation (=1) with 1 space.
-      GenerationCounters(name,
-                         1 /* ordinal */,
-                         1 /* spaces */,
-                         min_capacity /* min_capacity */,
-                         max_capacity /* max_capacity */,
-                         min_capacity /* curr_capacity */) {}
+  ZGenerationCounters(const char* name, int ordinal, int spaces,
+                      size_t min_capacity, size_t max_capacity, size_t curr_capacity) :
+      GenerationCounters(name, ordinal, spaces,
+                         min_capacity, max_capacity, curr_capacity) {}
 
-  virtual void update_all() {
-    size_t committed = ZHeap::heap()->capacity();
-    _current_size->set_value(committed);
+  void update_capacity(size_t capacity) {
+    _current_size->set_value(capacity);
   }
 };
 
 // Class to expose perf counters used by jstat.
 class ZServiceabilityCounters : public CHeapObj<mtGC> {
 private:
-  ZOldGenerationCounters _old_generation_counters;
-  HSpaceCounters         _old_space_counters;
-  CollectorCounters      _collector_counters;
+  ZGenerationCounters _generation_counters;
+  HSpaceCounters      _space_counters;
+  CollectorCounters   _collector_counters;
 
 public:
   ZServiceabilityCounters(size_t min_capacity, size_t max_capacity);
@@ -64,18 +59,21 @@
 
 ZServiceabilityCounters::ZServiceabilityCounters(size_t min_capacity, size_t max_capacity) :
     // generation.1
-    _old_generation_counters("old",
-                             min_capacity,
-                             max_capacity),
+    _generation_counters("old"        /* name */,
+                         1            /* ordinal */,
+                         1            /* spaces */,
+                         min_capacity /* min_capacity */,
+                         max_capacity /* max_capacity */,
+                         min_capacity /* curr_capacity */),
     // generation.1.space.0
-    _old_space_counters(_old_generation_counters.name_space(),
-                        "space",
-                        0 /* ordinal */,
-                        max_capacity /* max_capacity */,
-                        min_capacity /* init_capacity */),
+    _space_counters(_generation_counters.name_space(),
+                    "space"      /* name */,
+                    0            /* ordinal */,
+                    max_capacity /* max_capacity */,
+                    min_capacity /* init_capacity */),
     // gc.collector.2
-    _collector_counters("stop-the-world",
-                        2 /* ordinal */) {}
+    _collector_counters("stop-the-world" /* name */,
+                        2                /* ordinal */) {}
 
 CollectorCounters* ZServiceabilityCounters::collector_counters() {
   return &_collector_counters;
@@ -83,13 +81,12 @@
 
 void ZServiceabilityCounters::update_sizes() {
   if (UsePerfData) {
-    size_t capacity = ZHeap::heap()->capacity();
-    size_t used = MIN2(ZHeap::heap()->used(), capacity);
+    const size_t capacity = ZHeap::heap()->capacity();
+    const size_t used = MIN2(ZHeap::heap()->used(), capacity);
 
-    _old_space_counters.update_capacity(capacity);
-    _old_space_counters.update_used(used);
-
-    _old_generation_counters.update_all();
+    _generation_counters.update_capacity(capacity);
+    _space_counters.update_capacity(capacity);
+    _space_counters.update_used(used);
 
     MetaspaceCounters::update_performance_counters();
     CompressedClassSpaceCounters::update_performance_counters();