Re: wbt_lat_usec still set despite wbt disabled by BFQ

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

Hi, Holger

在 2022/08/18 1:12, Holger Hoffstätte 写道:
> I just noticed that my device configured with BFQ still shows wbt_lat_usec
> as configured, despite the fact that BFQ disables WBT in bfq_init_queue 
> [1]:
>
> $cat /sys/block/sdc/queue/scheduler
> mq-deadline [bfq] none
> $cat /sys/block/sdc/queue/wbt_lat_usec
> 75000
>
> Is this supposed to be 0 (since it's disabled) or is sysfs confused?
>
> Thanks,
> Holger

I'm reviewing wbt codes recently, and I found that this problem will
happen if the default elevator is bfq. I'll try to fix this, do you mind
if I add reported-by tag?

Thanks,
Kuai
> [1] 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/block/bfq-iosched.c#n7195 
>
>
> .