Re: [PATCH] sched/deadline: remove useless param from setup_new_dl_entity

[Steven Rostedt]

On Fri, 17 Jun 2016 10:48:41 +0100
Juri Lelli <juri.lelli@xxxxxxx> wrote:

> setup_new_dl_entity() takes two parameters, but it only actually uses
> one of them to setup a new dl_entity.
> 

Actually this patch is making it so that setup_new_dl_entity() only
uses one of the parameters. Can you note why that change happened.
Because this change log implies that the second parameter wasn't used
before this patch, and that is incorrect.

This patch reverts part of the change done in
commit 2d3d891d334 "sched/deadline: Add SCHED_DEADLINE inheritance
logic"

It would be nice to have the reason in the change log.

Thanks,

-- Steve


> Remove the second, useless, parameter.
> 
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Luca Abeni <luca.abeni@xxxxxxxx>
> Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx>
> ---
>  kernel/sched/deadline.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index fcb7f0217ff4..5229788a4765 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -346,8 +346,7 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
>   * one, and to (try to!) reconcile itself with its own scheduling
>   * parameters.
>   */
> -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
> -				       struct sched_dl_entity *pi_se)
> +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
>  {
>  	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
>  	struct rq *rq = rq_of_dl_rq(dl_rq);
> @@ -367,8 +366,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
>  	 * future; in fact, we must consider execution overheads (time
>  	 * spent on hardirq context, etc.).
>  	 */
> -	dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
> -	dl_se->runtime = pi_se->dl_runtime;
> +	dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline;
> +	dl_se->runtime = dl_se->dl_runtime;
>  }
>  
>  /*
> @@ -1721,7 +1720,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
>  static void switched_to_dl(struct rq *rq, struct task_struct *p)
>  {
>  	if (dl_time_before(p->dl.deadline, rq_clock(rq)))
> -		setup_new_dl_entity(&p->dl, &p->dl);
> +		setup_new_dl_entity(&p->dl);
>  
>  	if (task_on_rq_queued(p) && rq->curr != p) {
>  #ifdef CONFIG_SMP