Commit ffd44db5 authored Nov 10, 2009 by Peter Zijlstra Committed by Ingo Molnar Nov 10, 2009

sched: Make sure task has correct sched_class after policy change



From the code in rt_mutex_setprio(), it is evident that the
intention is that task's with a RT 'prio' value as a consequence
of receiving a PI boost also have their 'sched_class' field set
to '&rt_sched_class'.

However, Peter noticed that the code in __setscheduler() could
result in this intention being frustrated. Fix it.

Reported-by: Peter Williams <pwil3058@bigpond.net.au>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1257880321.4108.457.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent eae0c9df

kernel/sched.c

+4 −12

Original line number	Diff line number	Diff line
		@@ -6159,22 +6159,14 @@ __setscheduler(struct rq rq, struct task_struct p, int policy, int prio)
		BUG_ON(p->se.on_rq);

		p->policy = policy;
		switch (p->policy) {
		case SCHED_NORMAL:
		case SCHED_BATCH:
		case SCHED_IDLE:
		p->sched_class = &fair_sched_class;
		break;
		case SCHED_FIFO:
		case SCHED_RR:
		p->sched_class = &rt_sched_class;
		break;
		}

		p->rt_priority = prio;
		p->normal_prio = normal_prio(p);
		/* we are holding p->pi_lock already */
		p->prio = rt_mutex_getprio(p);
		if (rt_prio(p->prio))
		p->sched_class = &rt_sched_class;
		else
		p->sched_class = &fair_sched_class;
		set_load_weight(p);
		}