[PATCH] sched/fair: enqueue_task_fair optimization

[PATCH] sched/fair: enqueue_task_fair optimization

[Vincent Guittot]

enqueue_task_fair() jumps to enqueue_throttle when cfs_rq_of(se) is
throttled, which means that se can't be NULL and we can skip the test.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4b73518aa25c..910bbbe50365 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5512,7 +5512,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
                        list_add_leaf_cfs_rq(cfs_rq);
 	}
 
-enqueue_throttle:
 	if (!se) {
 		add_nr_running(rq, 1);
 		/*
@@ -5534,6 +5533,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 
 	}
 
+enqueue_throttle:
 	if (cfs_bandwidth_used()) {
 		/*
 		 * When bandwidth control is enabled; the cfs_rq_throttled()
-- 
2.17.1

Re: [PATCH] sched/fair: enqueue_task_fair optimization

[Pavan Kondeti]

On Mon, May 11, 2020 at 09:23:01PM +0200, Vincent Guittot wrote:
> enqueue_task_fair() jumps to enqueue_throttle when cfs_rq_of(se) is
> throttled, which means that se can't be NULL and we can skip the test.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 4b73518aa25c..910bbbe50365 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5512,7 +5512,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>                         list_add_leaf_cfs_rq(cfs_rq);
>  	}
>  
> -enqueue_throttle:
>  	if (!se) {
>  		add_nr_running(rq, 1);
>  		/*
> @@ -5534,6 +5533,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>  
>  	}
>  
> +enqueue_throttle:
>  	if (cfs_bandwidth_used()) {
>  		/*
>  		 * When bandwidth control is enabled; the cfs_rq_throttled()

Right, se can't be NULL when we break upon throttling. Looks good to me.

Thanks,
Pavan

-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH] sched/fair: enqueue_task_fair optimization

[Phil Auld]

On Mon, May 11, 2020 at 09:23:01PM +0200 Vincent Guittot wrote:
> enqueue_task_fair() jumps to enqueue_throttle when cfs_rq_of(se) is
> throttled, which means that se can't be NULL and we can skip the test.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 4b73518aa25c..910bbbe50365 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5512,7 +5512,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>                         list_add_leaf_cfs_rq(cfs_rq);
>  	}
>  
> -enqueue_throttle:
>  	if (!se) {
>  		add_nr_running(rq, 1);
>  		/*
> @@ -5534,6 +5533,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>  
>  	}
>  
> +enqueue_throttle:
>  	if (cfs_bandwidth_used()) {
>  		/*
>  		 * When bandwidth control is enabled; the cfs_rq_throttled()
> -- 
> 2.17.1
> 


Reviewed-by: Phil Auld <pauld@redhat.com>

--