Re: Re: [PATCH 1/4] sched/eevdf: Fix vruntime adjustment on reweight

[Abel Wu <wuyun.abel@bytedance.com>]

On 11/15/23 11:36 PM, Yiwei Lin Wrote:
> 
>> @@ -3712,8 +3811,17 @@ 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 (cfs_rq->curr != se)
>> -            avg_vruntime_add(cfs_rq, se);
>> +        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.
>> +             */
>> +            __enqueue_entity(cfs_rq, se);
>> +            update_min_vruntime(cfs_rq);
>> +        }
>>       }
>>   }
> Sorry if I am asking stupid question...... It looks like reweight_entity() may have chance to change the weight of cfs_rq->curr entity, but we'll never update_min_vruntime() when reweighting it. Is there any reason that we can skip the update_min_vruntime() for this case?

No, you are right!

Thanks!
	Abel