On Fri, Jan 17, 2014 at 10:04:04AM +0100, Daniel Lezcano wrote: > @@ -2679,11 +2715,8 @@ need_resched: > > pre_schedule(rq, prev); > > - if (unlikely(!rq->nr_running)) > - rq->idle_stamp = idle_balance(rq) ? 0 : rq_clock(rq); > - > put_prev_task(rq, prev); > - next = pick_next_task(rq); > + next = pick_next_task_or_idle(rq); > clear_tsk_need_resched(prev); > clear_preempt_need_resched(); > rq->skip_clock_update = 0;
I have vague memories that we need to have idle_balance() before put_prev_task(), but I can't recollect why this would be so. That said, if I resurrect these patches: https://lkml.org/lkml/2012/6/14/271 I suppose we could write something like: struct task_struct *pick_next_task(struct rq *rq, struct task_struct *prev) { const struct sched_class *class; struct task_struct *p; again: if (likely(rq->nr_running)) { if (likely(rq->nr_running == rq->cfs.h_nr_running)) return fair_sched_class.pick_next_task(rq, prev); for_each_class(class) { p = class->pick_next_task(rq, prev); if (p) return p; } } if (idle_balance(rq)) goto again; rq->idle_stamp = rq_clock(rq); return idle_sched_class.pick_next_task(rq, prev); } Which keeps idle_balance() before put_prev_task(), and by using idle_sched_clas.pick_next_task() doesn't rape the idle class interface like you did :-) -- 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/
