[jira] [Reopened] (HDFS-15160) ReplicaMap, Disk Balancer, Directory Scanner and various FsDatasetImpl methods should use datanode readlock

2021-07-12 Thread Ahmed Hussein (Jira)


 [ 
https://issues.apache.org/jira/browse/HDFS-15160?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Ahmed Hussein reopened HDFS-15160:
--

> ReplicaMap, Disk Balancer, Directory Scanner and various FsDatasetImpl 
> methods should use datanode readlock
> ---
>
> Key: HDFS-15160
> URL: https://issues.apache.org/jira/browse/HDFS-15160
> Project: Hadoop HDFS
>  Issue Type: Improvement
>  Components: datanode
>Affects Versions: 3.3.0
>Reporter: Stephen O'Donnell
>Assignee: Stephen O'Donnell
>Priority: Major
>  Labels: pull-request-available
> Fix For: 3.3.1, 3.4.0
>
> Attachments: HDFS-15160-branch-3.3-001.patch, HDFS-15160.001.patch, 
> HDFS-15160.002.patch, HDFS-15160.003.patch, HDFS-15160.004.patch, 
> HDFS-15160.005.patch, HDFS-15160.006.patch, HDFS-15160.007.patch, 
> HDFS-15160.008.patch, HDFS-15160.branch-3-3.001.patch, 
> image-2020-04-10-17-18-08-128.png, image-2020-04-10-17-18-55-938.png
>
>  Time Spent: 0.5h
>  Remaining Estimate: 0h
>
> Now we have HDFS-15150, we can start to move some DN operations to use the 
> read lock rather than the write lock to improve concurrence. The first step 
> is to make the changes to ReplicaMap, as many other methods make calls to it.
> This Jira switches read operations against the volume map to use the readLock 
> rather than the write lock.
> Additionally, some methods make a call to replicaMap.replicas() (eg 
> getBlockReports, getFinalizedBlocks, deepCopyReplica) and only use the result 
> in a read only fashion, so they can also be switched to using a readLock.
> Next is the directory scanner and disk balancer, which only require a read 
> lock.
> Finally (for this Jira) are various "low hanging fruit" items in BlockSender 
> and fsdatasetImpl where is it fairly obvious they only need a read lock.
> For now, I have avoided changing anything which looks too risky, as I think 
> its better to do any larger refactoring or risky changes each in their own 
> Jira.



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[jira] [Reopened] (HDFS-15160) ReplicaMap, Disk Balancer, Directory Scanner and various FsDatasetImpl methods should use datanode readlock

2021-03-24 Thread Stephen O'Donnell (Jira)


 [ 
https://issues.apache.org/jira/browse/HDFS-15160?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Stephen O'Donnell reopened HDFS-15160:
--

Reopening to backport to branch-3.3

> ReplicaMap, Disk Balancer, Directory Scanner and various FsDatasetImpl 
> methods should use datanode readlock
> ---
>
> Key: HDFS-15160
> URL: https://issues.apache.org/jira/browse/HDFS-15160
> Project: Hadoop HDFS
>  Issue Type: Improvement
>  Components: datanode
>Affects Versions: 3.3.0
>Reporter: Stephen O'Donnell
>Assignee: Stephen O'Donnell
>Priority: Major
> Fix For: 3.4.0
>
> Attachments: HDFS-15160.001.patch, HDFS-15160.002.patch, 
> HDFS-15160.003.patch, HDFS-15160.004.patch, HDFS-15160.005.patch, 
> HDFS-15160.006.patch, HDFS-15160.007.patch, HDFS-15160.008.patch, 
> image-2020-04-10-17-18-08-128.png, image-2020-04-10-17-18-55-938.png
>
>
> Now we have HDFS-15150, we can start to move some DN operations to use the 
> read lock rather than the write lock to improve concurrence. The first step 
> is to make the changes to ReplicaMap, as many other methods make calls to it.
> This Jira switches read operations against the volume map to use the readLock 
> rather than the write lock.
> Additionally, some methods make a call to replicaMap.replicas() (eg 
> getBlockReports, getFinalizedBlocks, deepCopyReplica) and only use the result 
> in a read only fashion, so they can also be switched to using a readLock.
> Next is the directory scanner and disk balancer, which only require a read 
> lock.
> Finally (for this Jira) are various "low hanging fruit" items in BlockSender 
> and fsdatasetImpl where is it fairly obvious they only need a read lock.
> For now, I have avoided changing anything which looks too risky, as I think 
> its better to do any larger refactoring or risky changes each in their own 
> Jira.



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