Few codes and docs refactor

core/src/main/scala/org/apache/spark/scheduler/cluster/CoarseGrainedSchedulerBackend.scala

@@ -54,9 +54,10 @@ class CoarseGrainedSchedulerBackend(scheduler: TaskSchedulerImpl, actorSystem: A
   private val akkaFrameSize = AkkaUtils.maxFrameSizeBytes(conf)
   // Submit tasks only after (registered resources / total expected resources) 
   // is equal to at least this value, that is double between 0 and 1.
-  var minRegisteredRatio = conf.getDouble("spark.scheduler.minRegisteredResourcesRatio", 0)
-  if (minRegisteredRatio > 1) minRegisteredRatio = 1
-  // Whatever minRegisteredRatio is arrived, submit tasks after the time(milliseconds).
+  var minRegisteredRatio =
+    math.min(1, conf.getDouble("spark.scheduler.minRegisteredResourcesRatio", 0))
+  // Submit tasks after maxRegisteredWaitingTime milliseconds
+  // if minRegisteredRatio has not yet been reached  
   val maxRegisteredWaitingTime =
     conf.getInt("spark.scheduler.maxRegisteredResourcesWaitingTime", 30000)
   val createTime = System.currentTimeMillis()
@@ -263,10 +264,10 @@ class CoarseGrainedSchedulerBackend(scheduler: TaskSchedulerImpl, actorSystem: A
     }
   }
 
-  def checkRegisteredResources(): Boolean = true
+  def sufficientResourcesRegistered(): Boolean = true
 
   override def isReady(): Boolean = {
-    if (checkRegisteredResources) {
+    if (sufficientResourcesRegistered) {
       logInfo("SchedulerBackend is ready for scheduling beginning" +
         ", total expected resources: " + totalExpectedResources.get() +
         ", minRegisteredResourcesRatio: " + minRegisteredRatio)

core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala

@@ -112,7 +112,7 @@ private[spark] class SparkDeploySchedulerBackend(
     removeExecutor(fullId.split("/")(1), reason.toString)
   }
 
-  override def checkRegisteredResources(): Boolean = {
+  override def sufficientResourcesRegistered(): Boolean = {
     totalCoreCount.get() >= totalExpectedResources.get() * minRegisteredRatio
   }
 }

docs/configuration.md

@@ -750,7 +750,7 @@ Apart from these, the following properties are also available, and may be useful
   <td>0</td>
   <td>
     The minimum ratio of registered resources (registered resources / total expected resources)
-    (resources are executors in yarn mode, CPU cores in standalone and mesos mode)
+    (resources are executors in yarn mode, CPU cores in standalone mode)
     to wait for before scheduling begins. Specified as a double between 0 and 1.
     Regardless of whether the minimum ratio of resources has been reached,
     the maximum amount of time it will wait before scheduling begins is controlled by config 

yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClientSchedulerBackend.scala

@@ -149,7 +149,7 @@ private[spark] class YarnClientSchedulerBackend(
     logInfo("Stopped")
   }
 
-  override def checkRegisteredResources(): Boolean = {
+  override def sufficientResourcesRegistered(): Boolean = {
     totalExecutors.get() >= totalExpectedResources.get() * minRegisteredRatio
   }
 }

yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClusterSchedulerBackend.scala

@@ -42,7 +42,7 @@ private[spark] class YarnClusterSchedulerBackend(
     totalExpectedResources.set(numExecutors)
   }
 
-  override def checkRegisteredResources(): Boolean = {
+  override def sufficientResourcesRegistered(): Boolean = {
     totalExecutors.get() >= totalExpectedResources.get() * minRegisteredRatio
   }
 }