[ Added linux-arch ] On Mon, 2010-02-01 at 17:29 +0100, Peter Zijlstra wrote: > 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. > So if we go with Linus's approach and make all archs guarantee that switch_mm() implies a full mb(), then we can simplify the sys_membarrier() code? That looks like the best approach. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html