Messages in this thread Patch in this message | | | Date | Thu, 19 Jun 2003 13:19:51 -0400 | From | "''" <> | Subject | Re: O(1) scheduler seems to lock up on sched_FIFO and sched_RR ta sks |
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> Hm! I wonder. Robert is working on a fix for schedsetschedule() > where it fails to actually tell the scheduler to switch to a process > that it just made higher priority or away from one it just lowered. > > The net result is that the caller keeps running (FIFO for all in this > case) when, in fact it should have been switched out. Next time > schedule() actually switches, it is all sorted out again. Could the > elavation of the events/0 thread cause this needed switch?
I posted a fix for this a month ago that was ignored. Which is a good thing, since now that I look at it again, I don't care for the approach I took nor does it appear to be complete.
Joe
----------- original posting
> Date: Wed, 21 May 2003 16:40:26 -0400 > From: Joe Korty <joe.korty@ccur.com> > To: Ingo Molnar <mingo@elte.hu> > Cc: linux-kernel@vger.kernel.org > Subject: [PATCH] setscheduler resched bug
setscheduler is not forcing a reschedule when needed like set_user_nice does. It should.
Joe
--- 2.5.69/kernel/sched.c.orig 2003-05-21 14:50:53.000000000 -0400 +++ 2.5.69/kernel/sched.c 2003-05-21 15:01:13.000000000 -0400 @@ -1716,6 +1716,7 @@ unsigned long flags; runqueue_t *rq; task_t *p; + int oldprio; if (!param || pid < 0) goto out_nounlock; @@ -1778,12 +1779,20 @@ retval = 0; p->policy = policy; p->rt_priority = lp.sched_priority; + oldprio = p->prio; if (policy != SCHED_NORMAL) p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority; else p->prio = p->static_prio; - if (array) + if (array) { __activate_task(p, task_rq(p)); + /* + * Reschedule if on a CPU and the priority dropped, or not on + * a CPU and the priority rose above the currently running task. + */ + if ((rq->curr == p) ? (p->prio > oldprio) : (p->prio < rq->curr->prio)) + resched_task(rq->curr); + } out_unlock: task_rq_unlock(rq, &flags); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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