reweight_eevdf() needs the latest V to do accurate calculation for new
ve and vd. So update V unconditionally when se is runnable.

Suggested-by: Abel Wu <wuyun.abel@bytedance.com>
Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
---
 kernel/sched/fair.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 03be0d1330a6..5551ce2af73e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3790,9 +3790,8 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
 
 	if (se->on_rq) {
 		/* commit outstanding execution time */
-		if (curr)
-			update_curr(cfs_rq);
-		else
+		update_curr(cfs_rq);
+		if (!curr)
 			__dequeue_entity(cfs_rq, se);
 		update_load_sub(&cfs_rq->load, se->load.weight);
 	}
-- 
2.39.3

On 3/4/24 11:00 AM, Tianchen Ding Wrote:
> reweight_eevdf() needs the latest V to do accurate calculation for new
> ve and vd. So update V unconditionally when se is runnable.

As this should come along with commit eab03c23c2a1, I think it would
be better add a Fixes tag?

> 
> Suggested-by: Abel Wu <wuyun.abel@bytedance.com>
> Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
> ---
>   kernel/sched/fair.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 03be0d1330a6..5551ce2af73e 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3790,9 +3790,8 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
>   
>   	if (se->on_rq) {
>   		/* commit outstanding execution time */
> -		if (curr)
> -			update_curr(cfs_rq);
> -		else
> +		update_curr(cfs_rq);
> +		if (!curr)
>   			__dequeue_entity(cfs_rq, se);
>   		update_load_sub(&cfs_rq->load, se->load.weight);
>   	}

On 2024/3/4 20:06, Abel Wu wrote:
> On 3/4/24 11:00 AM, Tianchen Ding Wrote:
>> reweight_eevdf() needs the latest V to do accurate calculation for new
>> ve and vd. So update V unconditionally when se is runnable.
> 
> As this should come along with commit eab03c23c2a1, I think it would
> be better add a Fixes tag?
> 

I'm not sure. In fact avg_vruntime_sub() in reweight_entity() was first 
introduced by af4cf40470c2, and at that time the algorithm about reweight was 
not completed...

On 3/5/24 10:13 AM, Tianchen Ding Wrote:
> On 2024/3/4 20:06, Abel Wu wrote:
>> On 3/4/24 11:00 AM, Tianchen Ding Wrote:
>>> reweight_eevdf() needs the latest V to do accurate calculation for new
>>> ve and vd. So update V unconditionally when se is runnable.
>>
>> As this should come along with commit eab03c23c2a1, I think it would
>> be better add a Fixes tag?
>>
> 
> I'm not sure. In fact avg_vruntime_sub() in reweight_entity() was first introduced by af4cf40470c2, and at that time the algorithm about reweight was not completed...
> 

It is because before commit eab03c23c2a1, reweight didn't rely on V.