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    SubjectRE: livepatch: change to a per-task consistency model
    On Tue, 24 May 2016, David Laight wrote:

    > > > Related, please can we have a flag for the sleep and/or process so that
    > > > an uninterruptible sleep doesn't trigger the 'hung task' detector
    > >
    > > TASK_KILLABLE
    >
    > Not sure that does what I want.
    > It appears to allow some 'kill' actions to wake the process.
    > I'm sure I've looked at the 'hung task' code since 2007.

    The trick is the

    if (t->state == TASK_UNINTERRUPTIBLE)

    test in check_hung_uninterruptible_tasks(). That makes sure that
    TASK_KILLABLE tasks (e.g. waiting on NFS I/O, but not limited only to
    that; feel free to set it whereever you need) are skipped. Please note
    that TASK_KILLABLE is actually a _mask_ that includes TASK_UNINTERRUPTIBLE
    as well; therefore the '==' test skips such tasks.

    --
    Jiri Kosina
    SUSE Labs

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