HBASE-16146 Remove thread local usage in Counter

hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java

@@ -108,25 +108,12 @@ public class Counter {
     return h;
   }
 
-  private static class IndexHolder {
-    int index = hash();
-  }
-
-  private final ThreadLocal<IndexHolder> indexHolderThreadLocal =
-      new ThreadLocal<IndexHolder>() {
-    @Override
-    protected IndexHolder initialValue() {
-      return new IndexHolder();
-    }
-  };
-
   public void add(long delta) {
     Container container = containerRef.get();
     Cell[] cells = container.cells;
     int mask = cells.length - 1;
 
-    IndexHolder indexHolder = indexHolderThreadLocal.get();
-    int baseIndex = indexHolder.index;
+    int baseIndex = hash();
     if(cells[baseIndex & mask].add(delta)) {
       return;
     }
@@ -139,8 +126,6 @@ public class Counter {
       index++;
     }
 
-    indexHolder.index = index;
-
     if(index - baseIndex >= cells.length &&
         cells.length < MAX_CELLS_LENGTH &&
         container.demoted.compareAndSet(false, true)) {
@@ -181,10 +166,6 @@ public class Counter {
     return sum;
   }
 
-  public void destroy() {
-    indexHolderThreadLocal.remove();
-  }
-
   @Override
   public String toString() {
     Cell[] cells = containerRef.get().cells;

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RpcServer.java

@@ -2011,7 +2011,6 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
           LOG.trace(ignored);
         }
       }
-      rpcCount.destroy();
     }
 
     private UserGroupInformation createUser(ConnectionHeader head) {