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https://issues.apache.org/jira/browse/YARN-6029?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15784388#comment-15784388
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Tao Yang commented on YARN-6029:
--------------------------------
Thanks [~wangda].
Updated priority to Critical and Attached new patch for review.
This patch needs add indentation in synchronized block. Diff code without
changing space like this:
{code}
@Override
- public synchronized CSAssignment assignContainers(Resource clusterResource,
+ public CSAssignment assignContainers(Resource clusterResource,
FiCaSchedulerNode node, ResourceLimits currentResourceLimits,
SchedulingMode schedulingMode) {
+ synchronized (this) {
updateCurrentResourceLimits(currentResourceLimits, clusterResource);
if (LOG.isDebugEnabled()) {
@@ -906,6 +907,7 @@ public synchronized CSAssignment assignContainers(Resource
clusterResource,
}
setPreemptionAllowed(currentResourceLimits, node.getPartition());
+ }
// Check for reserved resources
RMContainer reservedContainer = node.getReservedContainer();
@@ -923,6 +925,7 @@ public synchronized CSAssignment assignContainers(Resource
clusterResource,
}
}
+ synchronized (this) {
// if our queue cannot access this node, just return
if (schedulingMode == SchedulingMode.RESPECT_PARTITION_EXCLUSIVITY
&& !accessibleToPartition(node.getPartition())) {
@@ -1019,6 +1022,7 @@ public synchronized CSAssignment
assignContainers(Resource clusterResource,
return CSAssignment.NULL_ASSIGNMENT;
}
+ }
{code}
> CapacityScheduler deadlock when ParentQueue#getQueueUserAclInfo is called by
> Thread_A at the moment that Thread_B calls LeafQueue#assignContainers to
> release a reserved container
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: YARN-6029
> URL: https://issues.apache.org/jira/browse/YARN-6029
> Project: Hadoop YARN
> Issue Type: Bug
> Components: capacityscheduler
> Affects Versions: 2.8.0
> Reporter: Tao Yang
> Assignee: Tao Yang
> Priority: Critical
> Attachments: YARN-6029.001.patch, YARN-6029.002.patch, deadlock.jstack
>
>
> When ParentQueue#getQueueUserAclInfo is called (e.g. a client calls
> YarnClient#getQueueAclsInfo) just at the moment that
> LeafQueue#assignContainers is called and before notifying parent queue to
> release resource (should release a reserved container), then ResourceManager
> can deadlock. I found this problem on our testing environment for hadoop2.8.
> Reproduce the deadlock in chronological order
> * 1. Thread A (ResourceManager Event Processor) calls synchronized
> LeafQueue#assignContainers (got LeafQueue instance lock of queue root.a)
> * 2. Thread B (IPC Server handler) calls synchronized
> ParentQueue#getQueueUserAclInfo (got ParentQueue instance lock of queue
> root), iterates over children queue acls and is blocked when calling
> synchronized LeafQueue#getQueueUserAclInfo (the LeafQueue instance lock of
> queue root.a is hold by Thread A)
> * 3. Thread A wants to inform the parent queue that a container is being
> completed and is blocked when invoking synchronized
> ParentQueue#internalReleaseResource method (the ParentQueue instance lock of
> queue root is hold by Thread B)
> I think the synchronized modifier of LeafQueue#getQueueUserAclInfo can be
> removed to solve this problem, since this method appears to not affect fields
> of LeafQueue instance.
> Attach patch with UT for review.
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