diff --git a/core/src/main/scala/org/apache/spark/executor/TaskMetrics.scala b/core/src/main/scala/org/apache/spark/executor/TaskMetrics.scala
index 38b61d7242fce303d2aefd7e12bce1d6183d08d0..a3b4561b07e7fb2754df5283d5ef8289da56f24a 100644
--- a/core/src/main/scala/org/apache/spark/executor/TaskMetrics.scala
+++ b/core/src/main/scala/org/apache/spark/executor/TaskMetrics.scala
@@ -94,8 +94,8 @@ class TaskMetrics extends Serializable {
    */
   private var _diskBytesSpilled: Long = _
   def diskBytesSpilled: Long = _diskBytesSpilled
-  def incDiskBytesSpilled(value: Long): Unit = _diskBytesSpilled += value
-  def decDiskBytesSpilled(value: Long): Unit = _diskBytesSpilled -= value
+  private[spark] def incDiskBytesSpilled(value: Long): Unit = _diskBytesSpilled += value
+  private[spark] def decDiskBytesSpilled(value: Long): Unit = _diskBytesSpilled -= value
 
   /**
    * If this task reads from a HadoopRDD or from persisted data, metrics on how much data was read