Re: vfsmount lock issues on very large ppc64 box

From: Matthew Wilcox
Date: Sat Jul 16 2011 - 21:04:40 EST


On Sun, Jul 17, 2011 at 10:50:27AM +1000, Anton Blanchard wrote:
> Looking closer, all of these calls are in pipefs and sockfs.
> Since we never mount either filesystem they never get a long term
> reference and we always end up in the very slow write brlock path
> that takes a lock for each online CPU.
>
> Here is a quick hack that takes a long term reference on pipefs
> and sockfs which fixes the problem. Any thoughts on how we should
> fix it properly?

I know Tim and Andi have been looking into this ... I forget what their
fix was though.

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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