Re: [PATCH] sched/deadline: Always stop dl-server before changing parameters

[Valentin Schneider]

On 21/07/25 15:01, Juri Lelli wrote:
> Commit cccb45d7c4295 ("sched/deadline: Less agressive dl_server
> handling") reduced dl-server overhead by delaying disabling servers only
> after there are no fair task around for a whole period, which means that
> deadline entities are not dequeued right away on a server stop event.
> However, the delay opens up a window in which a request for changing
> server parameters can break per-runqueue running_bw tracking, as
> reported by Yuri.
>
> Close the problematic window by unconditionally calling dl_server_stop()
> before applying the new parameters (ensuring deadline entities go
> through an actual dequeue).
>
> Fixes: cccb45d7c4295 ("sched/deadline: Less agressive dl_server handling")
> Reported-by: Yuri Andriaccio <yurand2000@xxxxxxxxx>
> Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>

Reviewed-by: Valentin Schneider <vschneid@xxxxxxxxxx>