On Wed, Jun 04, 2014 at 10:58:29AM -0400, Tejun Heo wrote:

I think what Jens is planning is something really minimal.  Things
like [cb]fq heavily depend on the old block infrastructure.  I don't
know.  Maybe they can be merged in time but I'm not quite sure we'd
have enough pressure to actually do that.  Host-granular switching
should be good enough, I guess.

Jens told me he wanted to do a deadline scheduler, which actually is
the most sensible for disks unless you want all the cgroup magic.

Given that people in this thread are interested in more complex
schedulers I'd suggest they implement BFQ for blk-mq.