[HADOOP-14912] FairCallQueue may defer servicing calls

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.9.0, 3.0.0-alpha4, 2.8.2
• Fix Version/s: 2.9.0, 2.8.3, 3.0.0
• Component/s: ipc
• Target Version/s: 2.9.0, 2.8.3, 3.0.0
• Hadoop Flags: Reviewed
• Assignee: Daryn Sharp
• Reporter: Daryn Sharp
• Created: 27/Sep/17 21:02
• Updated: 10/Oct/17 20:26
• Resolved: 10/Oct/17 19:52

Description

HADOOP-14033 switched a lock to a semaphore to allow concurrency for producers & consumers to the underlying queues. A race condition was created that may cause a consumer to acquire a permit but not extract an element, leaving the semaphore with fewer permits than queued elements. This causes a minimum number of calls to always be present in the call queue.

Issue Links

• is broken by: HADOOP-14033 Reduce fair call queue lock contention