Re: [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists with insertion

From: Linus Torvalds (torvalds@transmeta.com)
Date: Fri Oct 12 2001 - 21:04:46 EST


On Fri, 12 Oct 2001, Davide Libenzi wrote:
>
> The problem is that even if cpu1 schedule the load of p before the
> load of *p and cpu2 does a = 1; wmb(); p = &a; , it could happen that
> even if from cpu2 the invalidation stream exit in order, cpu1 could see
> the value of p before the value of *p due a reordering done by the
> cache controller delivering the stream to cpu1.

Umm - if that happens, your cache controller isn't honouring the wmb(),
and you have problems quite regardless of any load ordering on _any_ CPU.

Ehh?

                Linus

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