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https://issues.apache.org/jira/browse/YARN-2009?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15513725#comment-15513725
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Eric Payne commented on YARN-2009:
----------------------------------

[~leftnoteasy], I have some concerns about this algorithm from above:
{code}
    for app in sort-by-fifo-or-priority(apps) {
       if (user-to-allocated.get(app.user) < user-limit-resource) {
            app.allocated = min(app.used + pending, user-limit-resource - 
user-to-allocated.get(app.user));
            user-to-allocated.get(app.user) += app.allocated;
       } else {
             // skip this app because user-limit reached
       }
    }
{code}
If {{Queue1}} has 100 resources, and if {{user1}} starts {{app1}} at priority 1 
that consumes the whole queue, won't {{user1}}'s {{user-limit-resource}} be 
100? Then, if {{user1}} starts another app ({{app2}}) at priority 2, won't the 
above algorithm skip over {{app2}} because {{user1}} has already achieved its 
{{user-limit-resource}}?

> Priority support for preemption in ProportionalCapacityPreemptionPolicy
> -----------------------------------------------------------------------
>
>                 Key: YARN-2009
>                 URL: https://issues.apache.org/jira/browse/YARN-2009
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: capacityscheduler
>            Reporter: Devaraj K
>            Assignee: Sunil G
>         Attachments: YARN-2009.0001.patch, YARN-2009.0002.patch
>
>
> While preempting containers based on the queue ideal assignment, we may need 
> to consider preempting the low priority application containers first.



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