[PATCH] Avoid unpaired stwcx. on some processors

Olof Johansson olof at lixom.net
Sun Nov 11 18:14:38 EST 2007

On Sun, Nov 11, 2007 at 03:46:05PM +1100, Benjamin Herrenschmidt wrote:
> > Seems like a "better" (but still ugly) workaround would be to create a
> > _new_ reservation to a RA that's unavailable to any userspace process,
> > so that they could never do a successful store to it. That way you would
> > have stray reservations, but never dangling stwcx:es. No?
> Many processors don't compare the reservation address locally. If
> there's any valid reservation held by that processor, a subsequent
> stwcx. will always succeed. That would make you scheme dangerous :-)

Yeah, I had missed that arch detail. Becky already explained it in her
reply, but thanks for doing it again. :)


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