Github user kayousterhout commented on a diff in the pull request:

    https://github.com/apache/spark/pull/13603#discussion_r67772507
  
    --- Diff: 
core/src/main/scala/org/apache/spark/scheduler/TaskSetManager.scala ---
    @@ -576,6 +576,62 @@ private[spark] class TaskSetManager(
       }
     
       /**
    +   * Check whether the given task set has been blacklisted to the point 
that it can't run anywhere.
    +   *
    +   * It is possible that this taskset has become impossible to schedule 
*anywhere* due to the
    +   * blacklist.  The most common scenario would be if there are fewer 
executors than
    +   * spark.task.maxFailures. We need to detect this so we can fail the 
task set, otherwise the job
    +   * will hang.
    +   *
    +   * The check here is a balance between being sure to catch the issue, 
but not wasting
    +   * too much time inside the scheduling loop.  Just check if the last 
task is schedulable
    +   * on any of the available executors.  So this is O(numExecutors) 
worst-case, but it'll
    +   * really be fast unless you've got a bunch of things blacklisted.  Its 
possible it won't detect
    +   * the unschedulable task immediately, but if it returns false, there is 
at least *some* task
    +   * that is schedulable, and after scheduling all of those, we'll 
eventually find the unschedulable
    +   * task.
    +   */
    +  private[scheduler] def abortIfTaskSetCompletelyBlacklisted(
    +      executorsByHost: HashMap[String, HashSet[String]]): Unit = {
    +    // If no executors have registered yet, don't abort the stage, just 
wait.  We probably
    +    // got here because a task set was added before the executors 
registered.
    +    if (executorsByHost.nonEmpty) {
    +      // take any task that needs to be scheduled, and see if we can find 
some executor it *could*
    +      // run on
    +      pollPendingTask.foreach { task =>
    +        executorsByHost.foreach { case (host, execs) =>
    +          execs.foreach { exec =>
    +            if (!executorIsBlacklisted(exec, task)) {
    +              return
    +            }
    +          }
    +        }
    +        abort(s"Aborting ${taskSet} because it has a task which cannot be 
scheduled on any" +
    --- End diff --
    
    Can you include the task ID here?


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