[YARN-4537] Pull out priority comparison from fifocomparator and use compound comparator for FifoOrdering policy

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: capacity scheduler
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: Rohith Sharma K S
• Reporter: Rohith Sharma K S
• Created: 04/Jan/16 10:31
• Updated: 30/Aug/16 01:08
• Resolved: 12/Jan/16 00:46

Description

Currently, priority comparison is integrated with FifoComparator. There should be a separate comparator defined for priority comparison so that down the line if any new ordering policy wants to integrate priority, they can use compound comparator where priority will be high preference.

The following changes are expected to be done as part of this JIRA

1. Pull out priority comparison from FifoComparator
2. Define new priority comparator
3. Use compound comparator for FifoOrderingPolicy. Oder of preference is Priority,FIFO