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https://issues.apache.org/jira/browse/HADOOP-9601?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13676059#comment-13676059
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Todd Lipcon commented on HADOOP-9601:
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Another thing which I think will have to be addressed before commit: I don't
think it's legal to use the THROW(...) macro inside of the array critical
region, since it allocates an object on the Java heap. This can create a
deadlock (eg that allocation could want to trigger a GC, but GC is blocked
because of the critical region). In the exception cases, we'll have to store
the exception message and type info on the C heap or stack, unlock the array,
and then throw the exception outside the critical region.
I think if you run the tests with -Xcheck:jni it should catch these cases where
other JNI calls are being used inside the critical region
> Support native CRC on byte arrays
> ---------------------------------
>
> Key: HADOOP-9601
> URL: https://issues.apache.org/jira/browse/HADOOP-9601
> Project: Hadoop Common
> Issue Type: Improvement
> Components: performance, util
> Affects Versions: 3.0.0
> Reporter: Todd Lipcon
> Attachments: HADOOP-9601-WIP-01.patch
>
>
> When we first implemented the Native CRC code, we only did so for direct byte
> buffers, because these correspond directly to native heap memory and thus
> make it easy to access via JNI. We'd generally assumed that accessing byte[]
> arrays from JNI was not efficient enough, but now that I know more about JNI
> I don't think that's true -- we just need to make sure that the critical
> sections where we lock the buffers are short.
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