diff mbox series

sched/fair: Update min_vruntime for reweight_entity() correctly

Message ID 20231117080106.12890-1-s921975628@gmail.com
State New
Headers
Series sched/fair: Update min_vruntime for reweight_entity() correctly |

Commit Message

Yiwei Lin Nov. 17, 2023, 8:01 a.m. UTC 
  Since reweight_entity() may have chance to change the weight of
cfs_rq->curr entity, we should also update_min_vruntime() if
this is the case

Fixes: eab03c23c2a1 ("sched/eevdf: Fix vruntime adjustment on reweight")
Signed-off-by: Yiwei Lin <s921975628@gmail.com>
---
 kernel/sched/fair.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

Comments

Abel Wu Nov. 17, 2023, 8:05 a.m. UTC | #1 
On 11/17/23 4:01 PM, Yiwei Lin Wrote:
> Since reweight_entity() may have chance to change the weight of
> cfs_rq->curr entity, we should also update_min_vruntime() if
> this is the case
> 
> Fixes: eab03c23c2a1 ("sched/eevdf: Fix vruntime adjustment on reweight")
> Signed-off-by: Yiwei Lin <s921975628@gmail.com>
> ---
>   kernel/sched/fair.c | 20 ++++++++++----------
>   1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 07f555857..6fb89f4a3 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3815,17 +3815,17 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
>   	enqueue_load_avg(cfs_rq, se);
>   	if (se->on_rq) {
>   		update_load_add(&cfs_rq->load, se->load.weight);
> -		if (!curr) {
> -			/*
> -			 * The entity's vruntime has been adjusted, so let's check
> -			 * whether the rq-wide min_vruntime needs updated too. Since
> -			 * the calculations above require stable min_vruntime rather
> -			 * than up-to-date one, we do the update at the end of the
> -			 * reweight process.
> -			 */
> +		if (!curr)
>   			__enqueue_entity(cfs_rq, se);
> -			update_min_vruntime(cfs_rq);
> -		}
> +
> +		/*
> +		 * The entity's vruntime has been adjusted, so let's check
> +		 * whether the rq-wide min_vruntime needs updated too. Since
> +		 * the calculations above require stable min_vruntime rather
> +		 * than up-to-date one, we do the update at the end of the
> +		 * reweight process.
> +		 */
> +		update_min_vruntime(cfs_rq);
>   	}
>   }
>   

Reviewed-by: Abel Wu <wuyun.abel@bytedance.com>

Thanks!
Peter Zijlstra Nov. 20, 2023, 11:48 a.m. UTC | #2 
On Fri, Nov 17, 2023 at 04:01:06PM +0800, Yiwei Lin wrote:
> Since reweight_entity() may have chance to change the weight of
> cfs_rq->curr entity, we should also update_min_vruntime() if
> this is the case
> 
> Fixes: eab03c23c2a1 ("sched/eevdf: Fix vruntime adjustment on reweight")
> Signed-off-by: Yiwei Lin <s921975628@gmail.com>


Right, but as you wrote in your other patch, min_vruntime isn't all that
critical anymore. I'll go queue this in sched/core, I don't think this
warrants /urgent.

> ---
>  kernel/sched/fair.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 07f555857..6fb89f4a3 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3815,17 +3815,17 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
>  	enqueue_load_avg(cfs_rq, se);
>  	if (se->on_rq) {
>  		update_load_add(&cfs_rq->load, se->load.weight);
> -		if (!curr) {
> -			/*
> -			 * The entity's vruntime has been adjusted, so let's check
> -			 * whether the rq-wide min_vruntime needs updated too. Since
> -			 * the calculations above require stable min_vruntime rather
> -			 * than up-to-date one, we do the update at the end of the
> -			 * reweight process.
> -			 */
> +		if (!curr)
>  			__enqueue_entity(cfs_rq, se);
> -			update_min_vruntime(cfs_rq);
> -		}
> +
> +		/*
> +		 * The entity's vruntime has been adjusted, so let's check
> +		 * whether the rq-wide min_vruntime needs updated too. Since
> +		 * the calculations above require stable min_vruntime rather
> +		 * than up-to-date one, we do the update at the end of the
> +		 * reweight process.
> +		 */
> +		update_min_vruntime(cfs_rq);
>  	}
>  }
>  
> -- 
> 2.34.1
>
diff mbox series

Patch

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 07f555857..6fb89f4a3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3815,17 +3815,17 @@  static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
 	enqueue_load_avg(cfs_rq, se);
 	if (se->on_rq) {
 		update_load_add(&cfs_rq->load, se->load.weight);
-		if (!curr) {
-			/*
-			 * The entity's vruntime has been adjusted, so let's check
-			 * whether the rq-wide min_vruntime needs updated too. Since
-			 * the calculations above require stable min_vruntime rather
-			 * than up-to-date one, we do the update at the end of the
-			 * reweight process.
-			 */
+		if (!curr)
 			__enqueue_entity(cfs_rq, se);
-			update_min_vruntime(cfs_rq);
-		}
+
+		/*
+		 * The entity's vruntime has been adjusted, so let's check
+		 * whether the rq-wide min_vruntime needs updated too. Since
+		 * the calculations above require stable min_vruntime rather
+		 * than up-to-date one, we do the update at the end of the
+		 * reweight process.
+		 */
+		update_min_vruntime(cfs_rq);
 	}
 }