Peter Zijlstra <[email protected]> writes:
> In order to avoid having to do put/set on a whole cgroup hierarchy > when we context switch, push the put into pick_next_task() so that > both operations are in the same function. Further changes then allow > us to possibly optimize away redundant work. > > Signed-off-by: Peter Zijlstra <[email protected]> > Link: http://lkml.kernel.org/r/1328936700.2476.17.camel@laptop > --- a/kernel/sched/idle_task.c > +++ b/kernel/sched/idle_task.c > @@ -23,8 +23,12 @@ static void check_preempt_curr_idle(stru > resched_task(rq->idle); > } > > -static struct task_struct *pick_next_task_idle(struct rq *rq) > +static struct task_struct * > +pick_next_task_idle(struct rq *rq, struct task_struct *prev) > { > + if (prev) > + prev->sched_class->put_prev_task(rq, prev); > + > schedstat_inc(rq, sched_goidle); > #ifdef CONFIG_SMP > idle_enter_fair(rq); > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -1310,15 +1310,7 @@ static struct task_struct *_pick_next_ta > { > struct sched_rt_entity *rt_se; > struct task_struct *p; > - struct rt_rq *rt_rq; > - > - rt_rq = &rq->rt; > - > - if (!rt_rq->rt_nr_running) > - return NULL; > - > - if (rt_rq_throttled(rt_rq)) > - return NULL; > + struct rt_rq *rt_rq = &rq->rt; > > do { > rt_se = pick_next_rt_entity(rq, rt_rq); > @@ -1332,9 +1324,22 @@ static struct task_struct *_pick_next_ta > return p; > } > > -static struct task_struct *pick_next_task_rt(struct rq *rq) > +static struct task_struct * > +pick_next_task_rt(struct rq *rq, struct task_struct *prev) > { > - struct task_struct *p = _pick_next_task_rt(rq); > + struct task_struct *p; > + struct rt_rq *rt_rq = &rq->rt; > + > + if (!rt_rq->rt_nr_running) > + return NULL; > + > + if (rt_rq_throttled(rt_rq)) > + return NULL; > + > + if (prev) > + prev->sched_class->put_prev_task(rq, prev); > + > + p = _pick_next_task_rt(rq); > > /* The running task is never eligible for pushing */ > if (p) p is now always non-NULL, so this branch can now go (and it is important that we can't fail after doing put). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
