[jira] [Created] (SPARK-40235) Use interruptible lock instead of synchronized in Executor.updateDependencies()

["Josh Rosen (Jira)" <ji...@apache.org>]

Josh Rosen created SPARK-40235:
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             Summary: Use interruptible lock instead of synchronized in Executor.updateDependencies()
                 Key: SPARK-40235
                 URL: https://issues.apache.org/jira/browse/SPARK-40235
             Project: Spark
          Issue Type: Improvement
          Components: Spark Core
    Affects Versions: 3.4.0
            Reporter: Josh Rosen
            Assignee: Josh Rosen


This patch modifies the synchronization in {{Executor.updateDependencies()}} in order to allow tasks to be interrupted while they are blocked and waiting on other tasks to finish downloading dependencies.

This synchronization was added years ago in [mesos/spark@{{{}7b9e96c{}}}|https://github.com/mesos/spark/commit/7b9e96c99206c0679d9925e0161fde738a5c7c3a] in order to prevent concurrently-launching tasks from performing concurrent dependency updates (file downloads, and, later, library installation). If one task is downloading dependencies, all other newly-launched tasks will block until the original dependency download is complete.

Let's say that a Spark task launches, becomes blocked on a {{updateDependencies()}} call, then is cancelled while it is blocked. Although Spark will send a Thread.interrupt() to the canceled task, the task will continue waiting because threads blocked on a {{synchronized}} won't throw an InterruptedException in response to the interrupt. As a result, the blocked thread will continue to wait until the other thread exits the synchronized block. 

In the wild, we saw a case where this happened and the thread remained blocked for over 1 minute, causing the TaskReaper to kick in and self-destruct the executor.

This PR aims to fix this problem by replacing the {{synchronized}} with a ReentrantLock, which has a {{lockInterruptibly}} method.



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