[PATCH] Fix race between pte_free and hash_page

Benjamin Herrenschmidt benh at kernel.crashing.org
Sat Dec 13 15:32:48 EST 2003

On Sat, 2003-12-13 at 04:20, Olof Johansson wrote:
> Benjamin Herrenschmidt wrote:
> >Unless I missed something, this should probably be applied to
> >ameslab-2.5 now.
> >
> >
> >
> Ben,
> I like it!  Two comments and one question:
> * Unless I'm missing something myself, (*batchp)->index is never
> initialized. I guess we might get lucky most the time, but it could
> cause badness.

Right. New patch on the way.

> * pte_freelist_forced_free is unprotected/nonatomic. It only seems to be
> used as an indicator of memory pressure so it's not a big problem. I'm
> guessing we don't really want to waste cycles on syncronization and can
> live with it not being exact.


> * Do we know how much extra IPI activity this causes on a fairly loaded
> system? It would be interesting to know.

I don't know at this point, I expect no much though, a system that can't
get one page with GFP_ATOMIC must be close to total oom...


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