[
https://issues.apache.org/jira/browse/YARN-4416?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Naganarasimha G R updated YARN-4416:
------------------------------------
Attachment: YARN-4416.v2.003.patch
Reverting the removal of lock on {{LeafQueue.getNumApplications}}
> Deadlock due to synchronised get Methods in AbstractCSQueue
> -----------------------------------------------------------
>
> Key: YARN-4416
> URL: https://issues.apache.org/jira/browse/YARN-4416
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: capacity scheduler, resourcemanager
> Affects Versions: 2.7.1
> Reporter: Naganarasimha G R
> Assignee: Naganarasimha G R
> Priority: Minor
> Attachments: YARN-4416.v1.001.patch, YARN-4416.v1.002.patch,
> YARN-4416.v2.001.patch, YARN-4416.v2.002.patch, YARN-4416.v2.003.patch,
> deadlock.log
>
>
> While debugging in eclipse came across a scenario where in i had to get to
> know the name of the queue but every time i tried to see the queue it was
> getting hung. On seeing the stack realized there was a deadlock but on
> analysis found out that it was only due to *queue.toString()* during
> debugging as {{AbstractCSQueue.getAbsoluteUsedCapacity}} was synchronized.
> Hence we need to ensure following :
> # queueCapacity, resource-usage has their own read/write lock hence
> synchronization is not req
> # numContainers is volatile hence synchronization is not req.
> # read/write lock could be added to Ordering Policy. Read operations don't
> need synchronized. So {{getNumApplications}} doesn't need synchronized.
> (First 2 will be handled in this jira and the third will be handled in
> YARN-4443)
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
