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    SubjectRe: [PATCH] sched: correct how RT task is picked
    On Wed, May 18, 2011 at 9:38 AM, Steven Rostedt <> wrote:
    >> I think you can take a look at next_prio(), it just calculate the
    >> next highest task on the current cpu; in this case,
    >> cpumask_test_cpu(cpu, &p->cpus_allowed) will be true for the most
    >> of time, but maybe that task is bound to this cpu.
    > I've been looking at the history here, and I think that '-1' is a relic.
    > If you look at sched_rt.c in f65eda4f789168ba5ff3fa75546c29efeed19f58:
    > $ git show f65eda4f:kernel/sched_rt.c
    > You'll see that push_rt_task calls pick_next_highest_task_rt() with a
    > -1. That code has long been replaced.

    Yeah, the condition "cpu < 0" could be removed since we have no
    that kind of caller.

    > I'm a bit nervous about taking Hillf's patch as is. But a little more
    > reviewing and testing may prove that it is legit.

    But another point is like I said before:
    'cpumask_test_cpu(cpu, &p->cpus_allowed)' doesn't equal to
    'p->rt.nr_cpus_allowed > 1' because we could have bounded
    So the condition 'if (cpumask_test_cpu(cpu, &p->cpus_allowed))'
    in Hillf's patch is not sufficient.


    Only stand for myself

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