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On Sat, Aug 11, 2007 at 08:54:46AM +0800, Herbert Xu wrote: > Chris Snook <csnook@redhat.com> wrote: > > > > cpu_relax() contains a barrier, so it should do the right thing. For > > non-smp architectures, I'm concerned about interacting with interrupt > > handlers. Some drivers do use atomic_* operations. > > What problems with interrupt handlers? Access to int/long must > be atomic or we're in big trouble anyway. Reordering due to compiler optimizations. CPU reordering does not affect interactions with interrupt handlers on a given CPU, but reordering due to compiler code-movement optimization does. Since volatile can in some cases suppress code-movement optimizations, it can affect interactions with interrupt handlers. Thanx, Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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