Re: [patch 2/3] scheduler: add full memory barriers upon taskswitch at runqueue lock/unlock

[Peter Zijlstra]

On Mon, 2010-02-01 at 11:24 -0500, Steven Rostedt wrote:
> 
> Doesn't set_bit imply a wmb()? If so couldn't we do:

Nope, that's what we have smp_mb__{before,after}_set_bit() for.

On x86 its a LOCK'ed op, so sure it implies a full membarrier, but not
in generic.

on x86 we have plenty serializing instructions before and after rq->curr
is set so none of the crazyness is needed at all. The only thing is !
x86.



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/