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    Subject[PATCH 3.16 111/114] sched,rt: Remove return value from pull_rt_task()
    3.16.36-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Peter Zijlstra <peterz@infradead.org>

    commit 8046d6806247088de5725eaf8a2580b29e50ac5a upstream.

    In order to be able to use pull_rt_task() from a callback, we need to
    do away with the return value.

    Since the return value indicates if we should reschedule, do this
    inside the function. Since not all callers currently do this, this can
    increase the number of reschedules due rt balancing.

    Too many reschedules is not a correctness issues, too few are.

    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Cc: ktkhai@parallels.com
    Cc: rostedt@goodmis.org
    Cc: juri.lelli@gmail.com
    Cc: pang.xunlei@linaro.org
    Cc: oleg@redhat.com
    Cc: wanpeng.li@linux.intel.com
    Cc: umgwanakikbuti@gmail.com
    Link: http://lkml.kernel.org/r/20150611124742.679002000@infradead.org
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    [Conflicts: kernel/sched/rt.c]
    Signed-off-by: Byungchul Park <byungchul.park@lge.com>
    [bwh: Backported to 3.16: use resched_task() instead of resched_curr()]
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    kernel/sched/rt.c | 20 ++++++++++----------
    1 file changed, 10 insertions(+), 10 deletions(-)

    --- a/kernel/sched/rt.c
    +++ b/kernel/sched/rt.c
    @@ -244,7 +244,7 @@ int alloc_rt_sched_group(struct task_gro

    #ifdef CONFIG_SMP

    -static int pull_rt_task(struct rq *this_rq);
    +static void pull_rt_task(struct rq *this_rq);

    static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
    {
    @@ -399,9 +399,8 @@ static inline bool need_pull_rt_task(str
    return false;
    }

    -static inline int pull_rt_task(struct rq *this_rq)
    +static inline void pull_rt_task(struct rq *this_rq)
    {
    - return 0;
    }

    static inline void queue_push_tasks(struct rq *rq)
    @@ -1772,14 +1771,15 @@ static void push_rt_tasks(struct rq *rq)
    ;
    }

    -static int pull_rt_task(struct rq *this_rq)
    +static void pull_rt_task(struct rq *this_rq)
    {
    - int this_cpu = this_rq->cpu, ret = 0, cpu;
    + int this_cpu = this_rq->cpu, cpu;
    + bool resched = false;
    struct task_struct *p;
    struct rq *src_rq;

    if (likely(!rt_overloaded(this_rq)))
    - return 0;
    + return;

    /*
    * Match the barrier from rt_set_overloaded; this guarantees that if we
    @@ -1836,7 +1836,7 @@ static int pull_rt_task(struct rq *this_
    if (p->prio < src_rq->curr->prio)
    goto skip;

    - ret = 1;
    + resched = true;

    deactivate_task(src_rq, p, 0);
    set_task_cpu(p, this_cpu);
    @@ -1852,7 +1852,8 @@ skip:
    double_unlock_balance(this_rq, src_rq);
    }

    - return ret;
    + if (resched)
    + resched_task(this_rq->curr);
    }

    /*
    @@ -1948,8 +1949,7 @@ static void switched_from_rt(struct rq *
    if (!p->on_rq || rq->rt.rt_nr_running)
    return;

    - if (pull_rt_task(rq))
    - resched_task(rq->curr);
    + pull_rt_task(rq);
    }

    void __init init_sched_rt_class(void)
    \
     
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