On Wed, Aug 08, 2007 at 06:48:24PM -0700, David Miller wrote: > From: Herbert Xu <[EMAIL PROTECTED]> > Date: Thu, 09 Aug 2007 09:03:27 +0800 > > > Such loops should always use something like cpu_relax() which comes > > with a barrier. > > This is an excellent point. > > And it needs to be weighed with the error prone'ness Andrew mentioned. > There probably is a middle ground somewhere.
OK... I'll bite. ACCESS_ONCE(), see http://lkml.org/lkml/2007/7/11/664. This would allow ACCESS_ONCE(atomic_read(&x)) to be used where refetching would be problematic, but allow the compiler free rein in cases where refetching is OK. The ACCESS_ONCE() primitive of course has its limitations as well, but you did ask for a middle ground. ;-) Thanx, Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
