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    SubjectRe: [PATCH 6/24] make atomic_read() behave consistently on frv
    On Wed, Aug 15, 2007 at 09:46:55PM +0200, Segher Boessenkool wrote:
    > >>>Well if there is only one memory location involved, then smp_rmb()
    > >>>isn't
    > >>>going to really do anything anyway, so it would be incorrect to use
    > >>>it.
    > >>
    > >>rmb() orders *any* two reads; that includes two reads from the same
    > >>location.
    > >
    > >If the two reads are to the same location, all CPUs I am aware of
    > >will maintain the ordering without need for a memory barrier.
    > That's true of course, although there is no real guarantee for that.

    A CPU that did not provide this property ("cache coherence") would be
    most emphatically reviled. So we are pretty safe assuming that CPUs
    will provide it.

    Thanx, Paul
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