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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