Messages in this thread | | | Date | Tue, 15 Nov 2005 18:18:19 +0800 | From | liyu <> | Subject | [Question]How to restrict some kind of task? |
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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; }
These code are so simple, but is make system crash, if I create some XYZ policy task. I tried the more radical idea (remove these tasks from runqueue to our one list_head that spin_lock protected), but crash again and again.
if need, I can paste my global patch. Thanks in advanced.
-liyu
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