Re: [PATCH 8/9] sched: Clean up idle task SMP logic

Vincent Guittot
2014-01-30T10:52:23Z

Hi Peter,

Acked-by: Vincent Guittot <vincent.guittot@linaro.org>

Vincent

On 28 January 2014 18:16, Peter Zijlstra <peterz@infradead.org> wrote:
> The idle post_schedule hook is just a vile waste of time, furthermore
> it appears unneeded, move the idle_enter_fair() call into
> pick_next_task_idle().
>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: alex.shi@linaro.org
> Cc: mingo@kernel.org
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Peter Zijlstra <peterz@infradead.org>
> ---
> kernel/sched/idle_task.c | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> --- a/kernel/sched/idle_task.c
> +++ b/kernel/sched/idle_task.c
> @@ -19,11 +19,6 @@ static void pre_schedule_idle(struct rq
> idle_exit_fair(rq);
> rq_last_tick_reset(rq);
> }
> -
> -static void post_schedule_idle(struct rq *rq)
> -{
> - idle_enter_fair(rq);
> -}
> #endif /* CONFIG_SMP */
> /*
> * Idle tasks are unconditionally rescheduled:
> @@ -40,8 +35,7 @@ pick_next_task_idle(struct rq *rq, struc
>
> schedstat_inc(rq, sched_goidle);
> #ifdef CONFIG_SMP
> - /* Trigger the post schedule to do an idle_enter for CFS */
> - rq->post_schedule = 1;
> + idle_enter_fair(rq);
> #endif
> return rq->idle;
> }
> @@ -105,7 +99,6 @@ const struct sched_class idle_sched_clas
> #ifdef CONFIG_SMP
> .select_task_rq = select_task_rq_idle,
> .pre_schedule = pre_schedule_idle,
> - .post_schedule = post_schedule_idle,
> #endif
>
> .set_curr_task = set_curr_task_idle,
>
>