revise patch

core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala

@@ -209,16 +209,15 @@ private[spark] class TaskSchedulerImpl(
   def resourceOffers(offers: Seq[WorkerOffer]): Seq[Seq[TaskDescription]] = synchronized {
     SparkEnv.set(sc.env)
 
-    val sortedTaskSets = rootPool.getSortedTaskSetQueue
     // Mark each slave as alive and remember its hostname
+    // Also track if new executor is added
+    var newExecAvail = false
     for (o <- offers) {
       executorIdToHost(o.executorId) = o.host
       if (!executorsByHost.contains(o.host)) {
         executorsByHost(o.host) = new HashSet[String]()
         executorAdded(o.executorId, o.host)
-        for (taskSet <- sortedTaskSets) {
-          taskSet.executorAdded(o.executorId, o.host)
-        }
+        newExecAvail = true
       }
     }
 
@@ -227,9 +226,13 @@ private[spark] class TaskSchedulerImpl(
     // Build a list of tasks to assign to each worker.
     val tasks = shuffledOffers.map(o => new ArrayBuffer[TaskDescription](o.cores))
     val availableCpus = shuffledOffers.map(o => o.cores).toArray
+    val sortedTaskSets = rootPool.getSortedTaskSetQueue
     for (taskSet <- sortedTaskSets) {
       logDebug("parentName: %s, name: %s, runningTasks: %s".format(
         taskSet.parent.name, taskSet.name, taskSet.runningTasks))
+      if (newExecAvail) {
+        taskSet.executorAdded()
+      }
     }
 
     // Take each TaskSet in our scheduling order, and then offer it each node in increasing order

core/src/main/scala/org/apache/spark/scheduler/TaskSetManager.scala

@@ -752,15 +752,12 @@ private[spark] class TaskSetManager(
   }
 
   // Re-compute pendingTasksWithNoPrefs since new preferred locations may become available
-  def executorAdded(execId: String, host: String) {
+  def executorAdded() {
     def newLocAvail(index: Int): Boolean = {
       for (loc <- tasks(index).preferredLocations) {
-        if (execId.equals(loc.executorId.getOrElse(null)) || host.equals(loc.host)) {
-          return true
-        }
-        val availRack = sched.getRackForHost(host)
-        val prefRack = sched.getRackForHost(loc.host)
-        if (prefRack.isDefined && prefRack.get.equals(availRack.getOrElse(null))) {
+        if (sched.hasExecutorsAliveOnHost(loc.host) ||
+          (loc.executorId.isDefined && sched.isExecutorAlive(loc.executorId.get)) ||
+          sched.getRackForHost(loc.host).isDefined) {
           return true
         }
       }