[YARN-2313] Livelock can occur in FairScheduler when there are lots of running apps

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.1
• Fix Version/s: 2.6.0
• Component/s: fairscheduler
• Hadoop Flags: Reviewed
• Assignee: Tsuyoshi Ozawa
• Reporter: Tsuyoshi Ozawa
• Created: 17/Jul/14 17:35
• Updated: 01/Dec/14 03:09
• Resolved: 23/Jul/14 05:02

Description

Observed livelock on FairScheduler when there are lots entry in queue. After my investigating code, following case can occur:

1. update() called by UpdateThread takes longer times than UPDATE_INTERVAL(500ms) if there are lots queue.
2. UpdateThread goes busy loop.
3. Other threads(AllocationFileReloader, ResourceManager$SchedulerEventDispatcher) can wait forever.