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Todd Lipcon commented on MAPREDUCE-1436: ---------------------------------------- Yep, I think your last bullet point is sufficient: there's an ordering of locks JT -> Scheduler -> JIP. A lock order is correct iff it is a subsequence of that ordering. > Deadlock in preemption code in fair scheduler > --------------------------------------------- > > Key: MAPREDUCE-1436 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-1436 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: contrib/fair-share > Affects Versions: 0.21.0, 0.22.0 > Reporter: Matei Zaharia > Assignee: Matei Zaharia > Priority: Blocker > Attachments: deadlock.png, mapreduce-1436-v2.patch, > mapreduce-1436.patch > > > In testing the fair scheduler with preemption, I found a deadlock between > updatePreemptionVariables and some code in the JobTracker. This was found > while testing a backport of the fair scheduler to Hadoop 0.20, but it looks > like it could also happen in trunk and 0.21. Details are in a comment below. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.