On Wed, Oct 26, 2016 at 05:13:07PM +0200, Arnd Bergmann wrote: > 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).
That would be my preference. Have a BFQ-variant for blk-mq as an option (default to off unless opted in by the driver or user), and not other scheduler for blk-mq. Don't bother with bfq for non blk-mq. It's not like there is any advantage in the legacy-request device even for slow devices, except for the option of having I/O scheduling.
