[PATCH] Fix race between pte_free and hash_page

[Olof Johansson]

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.

* 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.


Thanks,

-Olof


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