diff --git a/core/src/main/scala/org/apache/spark/internal/config/package.scala b/core/src/main/scala/org/apache/spark/internal/config/package.scala
index 0aed1af023f8..8bf615b23383 100644
--- a/core/src/main/scala/org/apache/spark/internal/config/package.scala
+++ b/core/src/main/scala/org/apache/spark/internal/config/package.scala
@@ -60,7 +60,7 @@ package object config {
     .createWithDefaultString("1g")
 
   private[spark] val DRIVER_MEMORY_OVERHEAD = ConfigBuilder("spark.driver.memoryOverhead")
-    .doc("The amount of off-heap memory to be allocated per driver in cluster mode, " +
+    .doc("The amount of non-heap memory to be allocated per driver in cluster mode, " +
       "in MiB unless otherwise specified.")
     .bytesConf(ByteUnit.MiB)
     .createOptional
@@ -185,7 +185,7 @@ package object config {
     .createWithDefaultString("1g")
 
   private[spark] val EXECUTOR_MEMORY_OVERHEAD = ConfigBuilder("spark.executor.memoryOverhead")
-    .doc("The amount of off-heap memory to be allocated per executor in cluster mode, " +
+    .doc("The amount of non-heap memory to be allocated per executor in cluster mode, " +
       "in MiB unless otherwise specified.")
     .bytesConf(ByteUnit.MiB)
     .createOptional
diff --git a/docs/configuration.md b/docs/configuration.md
index d0b2699a5dc7..c59626c34858 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -181,10 +181,16 @@ of the most common options to set are:
   <td><code>spark.driver.memoryOverhead</code></td>
   <td>driverMemory * 0.10, with minimum of 384 </td>
   <td>
-    The amount of off-heap memory to be allocated per driver in cluster mode, in MiB unless
-    otherwise specified. This is memory that accounts for things like VM overheads, interned strings, 
+    Amount of non-heap memory to be allocated per driver process in cluster mode, in MiB unless
+    otherwise specified. This is memory that accounts for things like VM overheads, interned strings,
     other native overheads, etc. This tends to grow with the container size (typically 6-10%). 
     This option is currently supported on YARN, Mesos and Kubernetes.
+    <em>Note:</em> Non-heap memory includes off-heap memory 
+    (when <code>spark.memory.offHeap.enabled=true</code>) and memory used by other driver processes
+    (e.g. python process that goes with a PySpark driver) and memory used by other non-driver 
+    processes running in the same container. The maximum memory size of container to running 
+    driver is determined by the sum of <code>spark.driver.memoryOverhead</code> 
+    and <code>spark.driver.memory</code>.
   </td>
 </tr>
 <tr>
@@ -215,10 +221,17 @@ of the most common options to set are:
  <td><code>spark.executor.memoryOverhead</code></td>
   <td>executorMemory * 0.10, with minimum of 384 </td>
   <td>
-    The amount of off-heap memory to be allocated per executor, in MiB unless otherwise specified.
-    This is memory that accounts for things like VM overheads, interned strings, other native 
-    overheads, etc. This tends to grow with the executor size (typically 6-10%).
+    Amount of non-heap memory to be allocated per executor process in cluster mode, in MiB unless
+    otherwise specified. This is memory that accounts for things like VM overheads, interned strings,
+    other native overheads, etc. This tends to grow with the executor size (typically 6-10%).
     This option is currently supported on YARN and Kubernetes.
+    <br/>
+    <em>Note:</em> Non-heap memory includes off-heap memory 
+    (when <code>spark.memory.offHeap.enabled=true</code>) and memory used by other executor processes
+    (e.g. python process that goes with a PySpark executor) and memory used by other non-executor 
+    processes running in the same container. The maximum memory size of container to running executor 
+    is determined by the sum of <code>spark.executor.memoryOverhead</code> and 
+    <code>spark.executor.memory</code>.
   </td>
 </tr>
 <tr>
@@ -1233,6 +1246,9 @@ Apart from these, the following properties are also available, and may be useful
   <td>
     If true, Spark will attempt to use off-heap memory for certain operations. If off-heap memory 
     use is enabled, then <code>spark.memory.offHeap.size</code> must be positive.
+    <em>Note:</em> If off-heap memory is enabled, may need to raise the non-heap memory size
+    (e.g. increase <code>spark.driver.memoryOverhead</code> or
+    <code>spark.executor.memoryOverhead</code>).
   </td>
 </tr>
 <tr>