Github user mridulm commented on a diff in the pull request: https://github.com/apache/spark/pull/16189#discussion_r92914887 --- Diff: core/src/main/scala/org/apache/spark/executor/Executor.scala --- @@ -432,6 +465,93 @@ private[spark] class Executor( } /** + * Supervises the killing / cancellation of a task by sending the interrupted flag, optionally + * sending a Thread.interrupt(), and monitoring the task until it finishes. + */ + private class TaskReaper( + taskRunner: TaskRunner, + val interruptThread: Boolean) + extends Runnable { + + private[this] val taskId: Long = taskRunner.taskId + + private[this] val killPollingIntervalMs: Long = + conf.getTimeAsMs("spark.task.reaper.pollingInterval", "10s") + + private[this] val killTimeoutMs: Long = conf.getTimeAsMs("spark.task.reaper.killTimeout", "2m") + + private[this] val takeThreadDump: Boolean = + conf.getBoolean("spark.task.reaper.threadDump", true) + + override def run(): Unit = { + val startTimeMs = System.currentTimeMillis() + def elapsedTimeMs = System.currentTimeMillis() - startTimeMs + def timeoutExceeded(): Boolean = killTimeoutMs > 0 && elapsedTimeMs > killTimeoutMs + try { + // Only attempt to kill the task once. If interruptThread = false then a second kill + // attempt would be a no-op and if interruptThread = true then it may not be safe or + // effective to interrupt multiple times: + taskRunner.kill(interruptThread = interruptThread) + // Monitor the killed task until it exits: + var finished: Boolean = false + while (!finished && !timeoutExceeded()) { + taskRunner.synchronized { + // We need to synchronize on the TaskRunner while checking whether the task has + // finished in order to avoid a race where the task is marked as finished right after + // we check and before we call wait(). + if (taskRunner.isFinished) { + finished = true + } else { + taskRunner.wait(killPollingIntervalMs) + } + } + if (taskRunner.isFinished) { + finished = true + } else { + logWarning(s"Killed task $taskId is still running after $elapsedTimeMs ms") + if (takeThreadDump) { + try { + Utils.getThreadDumpForThread(taskRunner.getThreadId).foreach { thread => --- End diff -- Neat !
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