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ASF GitHub Bot commented on YARN-6151: -------------------------------------- Github user kambatla commented on a diff in the pull request: https://github.com/apache/hadoop/pull/188#discussion_r99942869 --- Diff: hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSQueue.java --- @@ -236,6 +236,29 @@ public void setFairSharePreemptionThreshold(float fairSharePreemptionThreshold) } /** + * Recursively check if the queue can be preempted based on whether the + * resource usage is greater than fair share. + * + * @return true if the queue can be preempted + */ + public boolean canBePreempted() { + assert parent != null; --- End diff -- Why is this necessary? > FS Preemption doesn't filter out queues which cannot be preempted > ----------------------------------------------------------------- > > Key: YARN-6151 > URL: https://issues.apache.org/jira/browse/YARN-6151 > Project: Hadoop YARN > Issue Type: Bug > Components: fairscheduler > Affects Versions: 2.8.0 > Reporter: Yufei Gu > Assignee: Yufei Gu > Attachments: YARN-6151.branch-2.8.001.patch > > > This is preemption bug happens before 2.8.0, which also described in > YARN-3405. > Queue hierarchy described as below: > {noformat} > root > / \ > queue-1 queue-2 > / \ > queue-1-1 queue-1-2 > {noformat} > Assume cluster resource is 100 and all queues have same weights. > # queue-1-1 and queue-2 has apps. Each get 50 usage and 50 fairshare. > # When queue-1-2 is active, supposedly it will preempt 25 from queue-1-1, but > this doesn't happen because preemption happens top-down, queue-2 could be the > preemption candidate as long as queue-2 is less needy than queue-1, and > queue-2 doesn't exceed the fair share which means preemption won't happen. > We need to filter out queue-2 since it isn't a valid candidate. -- This message was sent by Atlassian JIRA (v6.3.15#6346) --------------------------------------------------------------------- To unsubscribe, e-mail: yarn-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: yarn-issues-h...@hadoop.apache.org