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Subject: Re: Bug in scheduler when using rt_mutex
From: Peter Zijlstra <peterz@infradead.org>
To: Yong Zhang <yong.zhang0@gmail.com>
Cc: samu.p.onkalo@nokia.com, mingo@elte.hu,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        tglx <tglx@linutronix.de>
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Date: Wed, 19 Jan 2011 11:38:18 +0100
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On Wed, 2011-01-19 at 10:44 +0100, Peter Zijlstra wrote:
> +static void
> +switched_from_fair(struct rq *rq, struct task_struct *p, int running)
> +{
> +       struct sched_entity *se = &p->se;
> +       struct cfs_rq *cfs_rq = cfs_rq_of(se);
> +
> +       if (!se->on_rq && p->state != TASK_RUNNING)
> +               se->vruntime -= cfs_rq->min_vruntime;
> +}
> +
>  /*
>   * We switched to the sched_fair class.
>   */
> -static void switched_to_fair(struct rq *rq, struct task_struct *p,
> -                            int running)
> +static void
> +switched_to_fair(struct rq *rq, struct task_struct *p, int running)
>  {
> +       struct sched_entity *se = &p->se;
> +       struct cfs_rq *cfs_rq = cfs_rq_of(se);
> +
> +       if (se->on_rq && cfs_rq->curr != se)
> +               __dequeue_entity(cfs_rq, se);
> +
> +       se->vruntimea += cfs_rq->min_vruntime;
> +
> +       if (se->on_rq && cfs_rq->curr != se)
> +               __enqueue_entity(cfs_rq, se);
> +
>         /*
>          * We were most likely switched from sched_rt, so
>          * kick off the schedule if running, otherwise just see 

Hrm, I think the to bit is not needed with the from thing in place, the
enqueue from _setprio will already have added min_vruntime