Re: [PATCH 1a/7] dlm: core locking

[Joel Becker <Joel.Becker@oracle.com>]

On Thu, Apr 28, 2005 at 02:48:57PM +0100, Stephen C. Tweedie wrote:
> reduce the latency for this case.  My gut feeling, though, is that I'd
> still prefer to see the DLM doing its work properly, cluster-wide in
> this case, as precaution against accidents if we get inconsistent states
> on disk leading to two nodes trying to create the same lock at once. 
> Experience suggests that such things *do* go wrong, and it's as well to
> plan for them --- early detection is good!

	And unacceptably slow.  With LKM_LOCAL, OCFS2 approaches ext3
speed untarring a kernel tree, because everything under the toplevel
directory is a candidate for LKM_LOCAL.  Network communication may be
fast, but pagecache operations are even faster.  I don't know by how
much, but I bet if we turned off LKM_LOCAL in the OCFS2 DLM, we'd lose a
lot of speed.

Joel

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Joel Becker
Senior Member of Technical Staff
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127