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    SubjectRe: [PATCH] sched_rt: Removes extra checking for nr_cpus_allowed when calling find_lowest_rq
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    On Tue, Oct 19, 2010 at 5:02 PM, Peter Zijlstra <peterz@infradead.org> wrote:
    > On Tue, 2010-10-19 at 16:57 +0600, Rakib Mullick wrote:
    >> sched_rt: Removes extra checking for nr_cpus_allowed when calling
    >> find_lowest_rq
    >
    > Why repeat this subject?

    Just trying to give a good looking format :-). Not sure whether it
    really is or not.
    >
    >
    > That's just not explaining anything.. what can go wrong, how does this
    > fix it.

    Actually it's not a fix. It just removes a check. It checks whether
    this process is movable to other processor or not. And this check is
    made from inside the find_lowest_cpu function. Thats why, the check
    before calling find_lowest_cpu has been removed. Is my explanation
    okay?

    Thanks,
    Rakib


    >
    >> Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
    >> ---
    >>
    >> --- linus-rc8/kernel/sched_rt.c       2010-10-15 05:26:43.000000000 +0600
    >> +++ rakib-rc8/kernel/sched_rt.c       2010-10-19 16:22:30.000000000 +0600
    >> @@ -971,8 +971,7 @@ select_task_rq_rt(struct rq *rq, struct
    >>        * that is just being woken and probably will have
    >>        * cold cache anyway.
    >>        */
    >> -     if (unlikely(rt_task(rq->curr)) &&
    >> -         (p->rt.nr_cpus_allowed > 1)) {
    >> +     if (unlikely(rt_task(rq->curr))) {
    >>               int cpu = find_lowest_rq(p);
    >>
    >>               return (cpu == -1) ? task_cpu(p) : cpu;
    >
    >
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