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    SubjectRe: [PATCH 4/5] kgdb: Use atomic operators which use barriers

    On Fri, 2 Apr 2010, Linus Torvalds wrote:
    > All that matters is that the above kind of while loop must work. The
    > architecture needs to do whatever it needs to do to make it work. End of
    > discussion. If on ARM6 that means "smp_mb()", then that's an ARM6
    > implementation issue.

    Put another way: from a kernel standpoint, cpu_relax() in _no_ way implies
    a memory barrier. That has always been true, and that continues to be

    But Linux does expect that if some other CPU modifies a memory location,
    then we _will_ see that modification eventually. If the CPU needs help to
    do so, then cpu_relax() needs to do that. Again - this has nothing to do
    with memory barriers. It's just a basic requirement.


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