[dm-devel] [RFC PATCH V2 00/13] block: support bio based io polling

[Mike Snitzer]

On Thu, Mar 18 2021 at 12:48pm -0400,
Ming Lei <ming.lei at redhat.com> wrote:

> Hi,
> 
> Add per-task io poll context for holding HIPRI blk-mq/underlying bios
> queued from bio based driver's io submission context, and reuse one bio
> padding field for storing 'cookie' returned from submit_bio() for these
> bios. Also explicitly end these bios in poll context by adding two
> new bio flags.
> 
> In this way, we needn't to poll all underlying hw queues any more,
> which is implemented in Jeffle's patches. And we can just poll hw queues
> in which there is HIPRI IO queued.
> 
> Usually io submission and io poll share same context, so the added io
> poll context data is just like one stack variable, and the cost for
> saving bios is cheap.
> 
> Any comments are welcome.

I really like your approach and am very encouraged by the early results
Jeffle has shared.

Please review my various nits for your next iteration of this patchset.
But I think you aren't far from these changes being ready to make the
5.13 merge, which is really pretty awesome.

Outstanding job Ming, thanks so much for taking on this line of work!

Mike