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    SubjectRe: [PATCH 2/3] work_on_cpu: Use our own workqueue.
    Ingo Molnar wrote:
    > * Oleg Nesterov <oleg@redhat.com> wrote:
    >
    >> But "[PATCH 1/3] work_on_cpu: dont try to get_online_cpus() in
    >> work_on_cpu." removes get_online_cpus/put_online_cpus, this means the
    >> work can run on the wrong CPU anyway. Or work_on_cpu() can hang forever
    >> if CPU has already gone away before queue_work_on().
    >>
    >> Confused.
    >
    > The idea was to require work_on_cpu() users to be CPU hotplug-safe. But
    > ... Rusty pointed it out in the past that this might be fragile, and we
    > could put back the get_online_cpus()/put_online_cpus() calls.
    >
    > Rusty, what do you think?
    >
    > Ingo


    I believe that is the intention, in that the caller should insure that
    the cpu does not go offline. But also as Rusty stated, the previous usages
    of set_cpus_allowed did not always insure this, so it's at least not a
    regression.

    I'll put it on my todo list to check the references in tip/cpus4096 to see
    where they stand on the get_online_cpus() issue.

    Thanks,
    Mike


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