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Posted to common-dev@hadoop.apache.org by "Kan Zhang (JIRA)" <ji...@apache.org> on 2009/06/05 02:56:07 UTC
[jira] Issue Comment Edited: (HADOOP-5859) FindBugs : fix "wait()
or sleep() with locks held" warnings in hdfs
[ https://issues.apache.org/jira/browse/HADOOP-5859?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12713180#action_12713180 ]
Kan Zhang edited comment on HADOOP-5859 at 6/4/09 5:55 PM:
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> Unless the variable is declared as "volatile", right?
I just checked, the JDK6 implementation of LinkedList didn't declare the "size" variable volatile. So Todd is right, a second thread may see a stale cached value. In any case, this is a non-issue after my refactoring. In the refactored code, all accesses to dataQueue or ackQueue are sync'ed on dataQueue lock.
was (Author: kzhang):
> Unless the variable is declared as "volatile", right?
I just checked, the JDK6 implementation of LinkedList didn't declare the "size" variable volatile. So Todd is right, a second thread may see a stale cached value (does anyone know how long the value will be cached by a thread, I hope it's not forever :)). In any case, this is a non-issue after my refactoring. In the refactored code, all accesses to dataQueue or ackQueue are sync'ed on dataQueue lock.
> FindBugs : fix "wait() or sleep() with locks held" warnings in hdfs
> -------------------------------------------------------------------
>
> Key: HADOOP-5859
> URL: https://issues.apache.org/jira/browse/HADOOP-5859
> Project: Hadoop Core
> Issue Type: Bug
> Components: dfs
> Reporter: Kan Zhang
> Assignee: Kan Zhang
> Fix For: 0.21.0
>
> Attachments: 5859-21.patch, 5859-22.patch, 5859-26.patch, 5859-33.patch, 5859-35.patch, 5859-36.patch, 5859-38.patch, 5859-4.patch, 5859-40.patch, 5859-41.patch, 5859-5.patch, 5859-8.patch
>
>
> This JIRA fixes the following warnings:
> SWL org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.closeInternal() calls Thread.sleep() with a lock held
> TLW wait() with two locks held in org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.flushInternal()
> TLW wait() with two locks held in org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.flushInternal()
> TLW wait() with two locks held in org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.writeChunk(byte[], int, int, byte[])
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