Re: [PATCH RFC v2 0/6] blk-throttle: support enable and disable during runtime

Yu Kuai
2024-04-17T01:09:13Z

Hi,

在 2024/04/16 23:56, Michal Koutný 写道:
> On Sat, Apr 06, 2024 at 04:00:53PM +0800, Yu Kuai <yukuai1@huaweicloud.com> wrote:
>> I'm planning to support build all blk-throttle polices as kernel module,
>
> There is only one blk-throttle policy (especially after your removal of
> io.low). Did you mean blkcg policies in general?

Yes, bfq already support that, and others are all rq_qos based, they
will be much easier than blk-throtl.
>
> The current code is complex because of various lifecycles in
> devices x cgroups.
> Turning policies into modules seems to make it
> devices x cgroups x policy modules
> .
>
> Could you please add more info why policies as modules is beneficial,
> how to keep complexity capped?

First of all, users can only load these policies when they need, and
reduce kernel size; Then, when these policies is not loaded, IO fast
path will be slightly shorter, and save some memory overhead for each
disk.

Thanks,
Kuai

>
> Thanks,
> Michal
>