Re: [PATCH] blk-throtl: optimize IOPS throttle for large IO scenarios

Tejun Heo
2021-07-28T07:48:10Z

Hello,

On Wed, Jul 28, 2021 at 10:33:20AM +0800, brookxu wrote:
> If we do this, I think we will encounter some problems, as follows:
> 1. blk-throttle is now at the top of the IO stack. Changing the position of the throttle hook
> will make this mechanism invalid for some devices.
> 2. We may also need to add a new hook to handle back-merge, otherwise I think the isolation
> effect will be worse in the sequential IO scene.
> 3. Since bio has entered the IO stack, if it is suspended and resubmitted by blk-throttle,
> then there is an IO stack reentry problem, which I think may cause many small problems.

Yeah, you're right. I don't think it's worth rocking the boat with
blk-throtl at this point. An extra callback it is then.

Thanks.

--
tejun