On Wednesday, October 26, 2016 8:05:11 AM CEST Bart Van Assche wrote: > On 10/26/2016 04:34 AM, Jan Kara wrote: > > On Wed 26-10-16 03:19:03, Christoph Hellwig wrote: > >> Just as last time: > >> > >> big NAK for introducing giant new infrastructure like a new I/O scheduler > >> for the legacy request structure. > >> > >> Please direct your engergy towards blk-mq instead. > > > > Christoph, we will probably talk about this next week but IMO rotating > > disks and SATA based SSDs are going to stay with us for another 15 years, > > likely more. For them blk-mq is no win, relatively complex IO scheduling > > like CFQ or BFQ does is a big win for them in some cases. So I think IO > > scheduling (and thus place for something like BFQ) is going to stay with us > > for quite a long time still. So are we going to add hooks in blk-mq to > > support full-blown IO scheduling at least for single queue devices? Or how > > else do we want to support that HW? > > Hello Jan, > > Having two versions (one for non-blk-mq, one for blk-mq) of every I/O > scheduler would be a maintenance nightmare. Has anyone already analyzed > whether it would be possible to come up with an API for I/O schedulers > that makes it possible to use the same I/O scheduler for both blk-mq and > the traditional block layer? The question to ask first is whether to actually have pluggable schedulers on blk-mq at all, or just have one that is meant to do the right thing in every case (and possibly can be bypassed completely). Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
