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https://issues.apache.org/jira/browse/HDFS-5957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13912210#comment-13912210
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Chris Nauroth commented on HDFS-5957:
-------------------------------------
[~gopalv], did you see my earlier comment about trying to downtune
{{dfs.client.mmap.cache.size}} to see if that helps? I misread some of this
code first time around and thought there was no way to get a synchronous
{{munmap}}, but that's not true.
[~cmccabe], I'll close this out once we have confirmation from Gopal that this
works for him.
> Provide support for different mmap cache retention policies in
> ShortCircuitCache.
> ---------------------------------------------------------------------------------
>
> Key: HDFS-5957
> URL: https://issues.apache.org/jira/browse/HDFS-5957
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Affects Versions: 2.3.0
> Reporter: Chris Nauroth
>
> Currently, the {{ShortCircuitCache}} retains {{mmap}} regions for reuse by
> multiple reads of the same block or by multiple threads. The eventual
> {{munmap}} executes on a background thread after an expiration period. Some
> client usage patterns would prefer strict bounds on this cache and
> deterministic cleanup by calling {{munmap}}. This issue proposes additional
> support for different caching policies that better fit these usage patterns.
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