2023-04-04 07:07:26

by Li zeming

Subject: [PATCH] sched: rt: Optimization function 'pick_next_rt_entity'

The moral of this function is to obtain the next RT scheduling entity
object,while 'list_entry' Implementation function of 'container_of'
returns the next RT scheduling entity object (no new code should be
added afterwards), directly returning 'list_entry' The execution result
is sufficient.

Signed-off-by: Li zeming <[email protected]>
---
kernel/sched/rt.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 0a11f44adee5..e9b1c08c20a7 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1769,7 +1769,6 @@ static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool f
static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
{
struct rt_prio_array *array = &rt_rq->active;
- struct sched_rt_entity *next = NULL;
struct list_head *queue;
int idx;

@@ -1779,9 +1778,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
queue = array->queue + idx;
if (SCHED_WARN_ON(list_empty(queue)))
return NULL;
- next = list_entry(queue->next, struct sched_rt_entity, run_list);

- return next;
+ return list_entry(queue->next, struct sched_rt_entity, run_list);
}

static struct task_struct *_pick_next_task_rt(struct rq *rq)
--
2.18.2

2023-04-05 23:07:36

by Tim Chen

Subject: Re: [PATCH] sched: rt: Optimization function 'pick_next_rt_entity'

On Thu, 2023-04-06 at 07:29 +0800, Li zeming wrote:
> The moral of this function is to obtain the next RT scheduling entity
> object,while 'list_entry' Implementation function of 'container_of'
> returns the next RT scheduling entity object (no new code should be
> added afterwards), directly returning 'list_entry' The execution result
> is sufficient.

Suggest changing the subject from "Optimization function 'pick_next_rt_entity'
to "Simplify pick_next_rt_entity()"

Suggest simplifying the comment:

Remove useless intermediate variable "next" and its initialization. Directly return the
next RT scheduling entity obtained from list_entry().

Otherwise the patch itself looks fine.

Reviewed-by: Tim Chen <[email protected]>
>
> Signed-off-by: Li zeming <[email protected]>
> ---
> kernel/sched/rt.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 0a11f44adee5..e9b1c08c20a7 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -1769,7 +1769,6 @@ static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool f
> static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
> {
> struct rt_prio_array *array = &rt_rq->active;
> - struct sched_rt_entity *next = NULL;
> struct list_head *queue;
> int idx;
>
> @@ -1779,9 +1778,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
> queue = array->queue + idx;
> if (SCHED_WARN_ON(list_empty(queue)))
> return NULL;
> - next = list_entry(queue->next, struct sched_rt_entity, run_list);
>
> - return next;
> + return list_entry(queue->next, struct sched_rt_entity, run_list);
> }
>
> static struct task_struct *_pick_next_task_rt(struct rq *rq)