Re: vfsmount lock issues on very large ppc64 box

From: Andi Kleen
Date: Sun Jul 17 2011 - 04:46:46 EST

On Sat, Jul 16, 2011 at 07:04:28PM -0600, Matthew Wilcox wrote:
> 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.

Tim posted a patch, but it wasn't applied for unknown reasons.

ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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