Re: [PATCH v4 0/2] sched/fair: Fix fair load state when switching to fair

[Andrea Righi]

Hi Zicheng,

On Wed, Jun 24, 2026 at 09:16:46AM +0000, Zicheng Qu wrote:
> Tasks outside fair may leave fair's sched_entity load state stale when
> they switch back to fair. Patch 1 rebuilds p->se.load from fair's
> switching_to hook, as in v3. Patch 2 keeps se->avg.load_avg in sync
> with the rebuilt load weight before the entity is attached back to fair.

Looks good to me.

Acked-by: Andrea Righi <arighi@xxxxxxxxxx>

Thanks,
-Andrea

> 
> Changes in v4:
> - Add Tejun's Acked-by to patch 1.
> - Split the PELT load_avg synchronization into patch 2.
> 
> Changes in v3:
> - Move the rebuild into fair's switching_to hook, as suggested by Peter.
>   This lets fair prepare its own state before enqueue and avoids adding a
>   sched_ext/fair-specific fixup to the generic sched_change_end() path.
> 
> Changes in v2:
> - Move the fix from scx_root_disable() to the class switch path so it also
>   covers partial-mode SCHED_EXT to SCHED_NORMAL transitions through
>   sched_setscheduler(). Andrea identified this missing case in the v1
>   discussion.
> 
> Zicheng Qu (2):
>   sched/fair: Rebuild load weight when switching to fair
>   sched/fair: Keep load_avg in sync after reweighting
> 
>  kernel/sched/fair.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
> 
> -- 
> 2.53.0