Re: [PATCH] sched/deadline: Exclude special DL entities from bandwidth moves

[Guopeng Zhang <guopeng.zhang@linux.dev>]

Hi Peter, Ingo,

Gentle ping on this patch.

It has received Reviewed-by from Christian and Acked-by from Juri.
Do you think it is suitable for the sched/core tree, or is there anything
else I should change?

Thanks,
Guopeng

在 2026/5/28 20:24, Juri Lelli 写道:
> Hello!
> 
> On 28/05/26 14:53, Guopeng Zhang wrote:
>> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>>
>> SUGOV special DL entities use fake/unused bandwidth. They are already
>> excluded from regular DL admission control, affinity admission checks,
>> rq bandwidth accounting, and root-domain rebuild accounting.
>>
>> dl_task_needs_bw_move() misses the same exclusion. As a result,
>> set_cpus_allowed_dl() and cpuset attach may treat a special DL entity as
>> requiring a root-domain bandwidth move when its affinity mask no longer
>> intersects the source root domain.
>>
>> Return false for special DL entities so root-domain bandwidth move
>> accounting follows the rest of the SUGOV special-entity handling.
>>
>> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
>> ---
>>  kernel/sched/deadline.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index ddfd6bc63ab1..3653166caa69 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -3142,7 +3142,7 @@ static void set_cpus_allowed_dl(struct task_struct *p,
>>  bool dl_task_needs_bw_move(struct task_struct *p,
>>  			   const struct cpumask *new_mask)
>>  {
>> -	if (!dl_task(p))
>> +	if (!dl_task(p) || dl_entity_is_special(&p->dl))
>>  		return false;
>>  
>>  	return !cpumask_intersects(task_rq(p)->rd->span, new_mask);
> 
> Makes sense to me.
> 
> Acked-by: Juri Lelli <juri.lelli@redhat.com>
> 
> Best,
> Juri
>