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Posted to yarn-issues@hadoop.apache.org by "Hudson (JIRA)" <ji...@apache.org> on 2018/11/18 15:24:00 UTC
[jira] [Commented] (YARN-8833) Avoid potential integer overflow
when computing fair shares
[ https://issues.apache.org/jira/browse/YARN-8833?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16690937#comment-16690937 ]
Hudson commented on YARN-8833:
------------------------------
FAILURE: Integrated in Jenkins build Hadoop-trunk-Commit #15456 (See [https://builds.apache.org/job/Hadoop-trunk-Commit/15456/])
YARN-8833. Avoid potential integer overflow when computing fair shares. (wwei: rev d027a24f0349b60efa5125c330058f123771748f)
* (edit) hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestComputeFairShares.java
* (edit) hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/policies/ComputeFairShares.java
> Avoid potential integer overflow when computing fair shares
> -----------------------------------------------------------
>
> Key: YARN-8833
> URL: https://issues.apache.org/jira/browse/YARN-8833
> Project: Hadoop YARN
> Issue Type: Bug
> Components: fairscheduler
> Reporter: liyakun
> Assignee: liyakun
> Priority: Major
> Fix For: 3.3.0
>
> Attachments: YARN-8833.1.patch, YARN-8833.2.patch, YARN-8833.3.patch, YARN-8833.patch
>
>
> When use w2rRatio compute fair share, there may be a chance triggering the problem of Int overflow, and entering an infinite loop.
> Since the compute share thread holds the writeLock, it may blocking scheduling thread.
> This issue occurs in a production environment with 8500 nodes. And we have already fixed it.
>
> added 2018-10-29: elaborate the problem
> /**
> * Compute the resources that would be used given a weight-to-resource ratio
> * w2rRatio, for use in the computeFairShares algorithm as described in #
> */
> private static int resourceUsedWithWeightToResourceRatio(double w2rRatio,
> Collection<? extends Schedulable> schedulables, String type) \{ int resourcesTaken = 0; for (Schedulable sched : schedulables) \{ int share = computeShare(sched, w2rRatio, type); resourcesTaken += share; }
> return resourcesTaken;
> }
> The variable resourcesTaken is an integer type. And it also is accumulated value of result of
> computeShare(Schedulable sched, double w2rRatio,String type) which is a value between the min share and max share of a queue.
> For example, when there are 3 queues, each has min share = max share =
> Integer.MAX_VALUE, the resourcesTaken will be out of Integer bound, and it will be a negative number.
> when resourceUsedWithWeightToResourceRatio(double w2rRatio, Collection<? extends Schedulable> schedulables, String type) return a negative number, the loop in
> computeSharesInternal() may never out which got the scheduler lock.
>
> //org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.ComputeFairShares
> while (resourceUsedWithWeightToResourceRatio(rMax, schedulables, type)
> < totalResource)
> { rMax *= 2.0; }
> This may blocking scheduling thread.
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