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    SubjectRe: [BUG] cpu-hotplug: Can't offline the CPU with naughty realtime processes
    On Mon, May 07, 2007 at 04:32:56PM +0530, Srivatsa Vaddagiri wrote:
    > On Mon, May 07, 2007 at 04:17:24PM +0530, Gautham R Shenoy wrote:
    > > Nevertheless, with the freezer based approach that we're experimenting,
    > > this problem shouldn't arise. We expect the whole system to get frozen
    > > before we actually do a cpu_down() (which will then call
    > > __stop_machine_run). So any such rogue RT task will have to first fail
    > > the freezer ( which it will),
    > >From what I understand of the freezer, if the RT task is running in user
    > space (which seems to be the case in this thread), it should get frozen even
    > if it is a forever running SCHED_FIFO task at MAX_RT_PRIO -1 priority?

    Yes, you are right. It will end up getting the fake signal.
    So yeah, freezer pretty much solves the problem for cpu hotplug.

    But I now wonder if we will have some problem with module stopping if we
    have a high prio SCHED_FIFO in the system.

    > --
    > Regards,
    > vatsa

    Gautham R Shenoy
    Linux Technology Center
    IBM India.
    "Freedom comes with a price tag of responsibility, which is still a bargain,
    because Freedom is priceless!"
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      Last update: 2007-05-07 14:43    [W:0.020 / U:91.600 seconds]
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