Re: [PATCH] sched/fair: fix pick_eevdf to always find the correct se

[Marek Szyprowski]

On 06.10.2023 21:24, Peter Zijlstra wrote:
> On Fri, Oct 06, 2023 at 05:55:01PM +0200, Peter Zijlstra wrote:
>> And yeah, min_deadline is hosed somehow.
>>
>> migration/28-185     [028] d..2.    70.264274: validate_cfs_rq: --- /
>> migration/28-185     [028] d..2.    70.264277: __print_se: ffff88845cf48080 w: 1024 ve: -58857638 lag: 870381 vd: -55861854 vmd: -66302085 E (11372/tr)
>> migration/28-185     [028] d..2.    70.264280: __print_se:   ffff88810d165800 w: 25 ve: -80323686 lag: 22336429 vd: -41496434 vmd: -66302085 E (-1//autogroup-31)
>> migration/28-185     [028] d..2.    70.264282: __print_se:   ffff888108379000 w: 25 ve: 0 lag: -57987257 vd: 114632828 vmd: 114632828 N (-1//autogroup-33)
>> migration/28-185     [028] d..2.    70.264283: validate_cfs_rq: min_deadline: -55861854 avg_vruntime: -62278313462 / 1074 = -57987256
>>
>> I need to go make dinner (kids hungry), but I'll see if I can figure out
>> how this happens...
> *sigh*, does the below help?

It looks that this fixed the issue. At least I was no longer able to 
reproduce it.

Feel free to add:

Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>

Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>

> ---
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 04fbcbda97d5..6a670f119efa 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3632,6 +3747,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
>   		 */
>   		deadline = div_s64(deadline * old_weight, weight);
>   		se->deadline = se->vruntime + deadline;
> +		min_deadline_cb_propagate(&se->run_node, NULL);
>   	}
>   
>   #ifdef CONFIG_SMP
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland