Re: [rfc][patch] i386: remove comment about barriers

From: Davide Libenzi
Date: Sat Sep 29 2007 - 15:13:15 EST


On Sat, 29 Sep 2007, Nick Piggin wrote:

> [ This is true for x86's sfence/lfence, but raises a question about Linux's
> memory barriers. Does anybody expect that a sequence of smp_wmb and smp_rmb
> would ever provide a full smp_mb barrier? I've always assumed no, but I
> don't know if it is actually documented? ]

No, that can't be. rmb+wmb can't be considered a full mb. There was a
recent discussion about this in the thread originated by peterz scalable
rw_mutex patches.



- Davide


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