Re: [PATCH] cfq-iosched: fix the delay of cfq_group's vdisktime under iops mode

[Vivek Goyal <vgoyal@redhat.com>]

On Fri, Mar 03, 2017 at 09:20:44PM +0800, Hou Tao wrote:

[..]
> > Frankly, vdisktime is in fixed-point precision shifted by
> > CFQ_SERVICE_SHIFT so using CFQ_IDLE_DELAY does not make much sense in any
> > case and just adding 1 to maximum vdisktime should be fine in all the
> > cases. But that would require more testing whether I did not miss anything
> > subtle.

I think even 1 will work. But in the beginning IIRC I took the idea
from cpu scheduler. Adding a value bigger than 1 will allow you to add
some other group later before this group. (If you want to give that group
higher priority).

Thanks
Vivek