RE: Synchronizing Bit operations V2

From: Chen, Kenneth W
Date: Thu Mar 30 2006 - 19:46:57 EST


Christoph Lameter wrote on Thursday, March 30, 2006 4:45 PM
> > I would make that MODE_RELEASE for clear_bit, simply to match the
> > observation that clear_bit is usually used in unlock path and have
> > potential less surprises.
>
> clear_bit per se is defined as an atomic operation with no implications
> for release or acquire. If it is used for release then either add the
> appropriate barrier or use MODE_RELEASE explicitly.
>
> It precise the uncleanness in ia64 that such semantics are attached to
> these bit operations which may lead people to depend on those. We need to
> either make these explicit or not depend on them.

I know, I'm saying since it doesn't make any difference from API point of
view whether it is acq, rel, or no ordering, then just make them rel as a
"preferred" Operation on ia64.

- Ken
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