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https://issues.apache.org/jira/browse/YARN-1458?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13836009#comment-13836009
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mai shurong commented on YARN-1458:
-----------------------------------
I read the related code, and I find the code below may be the reason that the
fairscheduler object lock is always held.
In some exceptional case(not verified, just guess), some abnormal jobs are
contained, which may cause the endless loop(while loop) , so the lock is not
released.
//file:
org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.ComputeFairShares:
line 102
while (resourceUsedWithWeightToResourceRatio(rMax, schedulables, type) <
totalResource) {
rMax *= 2.0;
}
I try to modify the code . I add a counter of the loop and break the loop when
the counter is up to a threshold(here is 30 ).
The example code is below:
int count = 0;
while (resourceUsedWithWeightToResourceRatio(rMax, schedulables, type) <
totalResource and count < 30) {
rMax *= 2.0;
++count;
}
The correctness of code modification is not verified and need some experiments
and tests.
> hadoop2.2.0 fairscheduler ResourceManager Event Processor thread blocked
> ------------------------------------------------------------------------
>
> Key: YARN-1458
> URL: https://issues.apache.org/jira/browse/YARN-1458
> Project: Hadoop YARN
> Issue Type: Bug
> Components: scheduler
> Affects Versions: 2.2.0
> Environment: Centos 2.6.18-238.19.1.el5 X86_64
> hadoop2.2.0
> Reporter: qingwu.fu
> Labels: patch
> Original Estimate: 408h
> Remaining Estimate: 408h
>
> The ResourceManager$SchedulerEventDispatcher$EventProcessor blocked when
> clients submit lots jobs, it is not easy to reapear. We run the test cluster
> for days to reapear it. The output of jstack command on resourcemanager pid:
> "ResourceManager Event Processor" prio=10 tid=0x00002aaab0c5f000 nid=0x5dd3
> waiting for monitor entry [0x0000000043aa9000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.removeApplication(FairScheduler.java:671)
> - waiting to lock <0x000000070026b6e0> (a
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:1023)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:112)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager$SchedulerEventDispatcher$EventProcessor.run(ResourceManager.java:440)
> at java.lang.Thread.run(Thread.java:744)
> ……
> "FairSchedulerUpdateThread" daemon prio=10 tid=0x00002aaab0a2c800 nid=0x5dc8
> runnable [0x00000000433a2000]
> java.lang.Thread.State: RUNNABLE
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.getAppWeight(FairScheduler.java:545)
> - locked <0x000000070026b6e0> (a
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.AppSchedulable.getWeights(AppSchedulable.java:129)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.ComputeFairShares.computeShare(ComputeFairShares.java:143)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.ComputeFairShares.resourceUsedWithWeightToResourceRatio(ComputeFairShares.java:131)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.ComputeFairShares.computeShares(ComputeFairShares.java:102)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.policies.FairSharePolicy.computeShares(FairSharePolicy.java:119)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FSLeafQueue.recomputeShares(FSLeafQueue.java:100)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FSParentQueue.recomputeShares(FSParentQueue.java:62)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.update(FairScheduler.java:282)
> - locked <0x000000070026b6e0> (a
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler$UpdateThread.run(FairScheduler.java:255)
> at java.lang.Thread.run(Thread.java:744)
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