From: Con Kolivas <kernel@kolivas.org>
To: liyu@ccoss.com.cn
Subject: Re: [Question]How to restrict some kind of task?
Date: Tue, 15 Nov 2005 21:21:29 +1100
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On Tue, 15 Nov 2005 21:18, liyu wrote:
> Hi, All.
>
>     I want to restrict some kind of task.
>
>     For example, for some task have one schedule policy SCHED_XYZ, when
> it reach beyond
> 40% CPU time, we force it yield CPU.
>
>     I inserted some code in scheduler_tick(), like this:
> >         if (check_task_overload(rq)) {
> >                 if (xyz_task(p) && yield_cpu(p, rq)) {
> >                         set_tsk_need_resched(p);
> >                         p->prio = effective_prio(p);
> >                         p->time_slice = task_timeslice(p);
> >                         p->first_time_slice = 0;
> >                         goto out_unlock;
> >                 }
> >         }
>
>     Of course, before these code, we hold our rq->lock first, so we should
> go to 'out_unlock'.
>     The function xyz_task(p) just is macro (p->policy == SCHED_XYZ), and
> yield_cpu() also is simple, it just move the task to expired array,
>
> int yield_cpu(task_t *p, runqueue_t *rq)
> {
>     dequeue_task(p, p->array);
>     requeue_task(p, rq->expired);
>     return 1;
> }

Don't requeue after dequeue. You enqueue after dequeue.

Con
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