GitHub user budde opened a pull request:
https://github.com/apache/spark/pull/11012
[SPARK-13122] Fix race condition in MemoryStore.unrollSafely()
https://issues.apache.org/jira/browse/SPARK-13122
A race condition can occur in MemoryStore's unrollSafely() method if two
threads that
return the same value for currentTaskAttemptId() execute this method
concurrently. This
change makes the operation of reading the initial amount of unroll memory
used, performing
the unroll, and updating the associated memory maps atomic in order to
avoid this race
condition.
Initial proposed fix wraps all of unrollSafely() in a
memoryManager.synchronized { } block. A cleaner approach might be introduce a
mechanism that synchronizes based on task attempt ID. An alternative option
might be to track unroll/pending unroll memory based on block ID rather than
task attempt ID.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/budde/spark master
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/11012.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #11012
----
commit 6e0156c6e3c2fd137005ce3d55cecdf7070795da
Author: Adam Budde <bu...@amazon.com>
Date: 2016-02-02T01:04:45Z
[SPARK-13122] Fix race condition in MemoryStore.unrollSafely()
https://issues.apache.org/jira/browse/SPARK-13122
A race condition can occur in MemoryStore's unrollSafely() method if two
threads that
return the same value for currentTaskAttemptId() execute this method
concurrently. This
change makes the operation of reading the initial amount of unroll memory
used, performing
the unroll, and updating the associated memory maps atomic in order to
avoid this race
condition.
----
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