Re: request->ioprio

[Divyesh Shah]

On Aug 6, 2008, at 2:32 AM, Fernando Luis Vázquez Cao wrote:

> (CCing LKML)
>
> Hi Jens, Rusty,
>
> Trying to implement i/o tracking all the way up to the page cache (so
> that cfq and the future cgroup-based I/O controllers can schedule
> buffered I/O properly) I noticed that struct request's ioprio is
> initialized but never used for I/O scheduling purposes. Indeed there
> seems to be one single user of this member: virtio_blk. Virtio uses
> struct request's ioprio in the request() function of the virtio block
> driver, which just copies the ioprio value to the output header of
> virtblk_req.
>
> Is this the intended use of struct request's ioprio? Is it OK for  
> device
> drivers to use it? If the answer two the previous to questions is no I
> would like to send some clean-up patches.

Naveen Gupta sent a priority-based anticipatory IO scheduler patchset  
earlier which uses request->ioprio and the struct request seems to be  
the logical place to keep the ioprio. So, please don't cleanup the  
ioprio from there.

Thanks,
Divyesh

> - Fernando



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/