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