[dm-devel] dm-mpath: Work with blk multi-queue drivers

[Mike Snitzer]

On Wed, Sep 24 2014 at  2:48pm -0400,
Mike Snitzer <snitzer at redhat.com> wrote:

> On Wed, Sep 24 2014 at  2:34pm -0400,
> Mike Snitzer <snitzer at redhat.com> wrote:
> 
> > 
> > I never did take the time to properly review Hannes' proposal but now
> > that you're floating this blk-mq support for DM core (and DM mpath) I'm
> > clearly going to have to take this all on in a much more focused way.
> > 
> > Christoph/Hannes/Junichi/Keith/others, can you see a way forward that
> > offers a lighter request-based DM that makes required callouts to (new?)
> > block interfaces that helps us abstract the old request and blk-mq
> > request allocation, etc?
> 
> (sorry about replying to myself...)
> 
> SO revisiting that thread from above, these posts stand out:
> http://www.redhat.com/archives/dm-devel/2014-June/msg00026.html
> http://www.redhat.com/archives/dm-devel/2014-June/msg00028.html
> 
> I'd love to see us get rid of request-based DM's bio cloning for each
> cloned request (we never did get an answer from the NEC guys to know
> _why_ that was done).

Actually, Junichi did respond with why:
http://www.redhat.com/archives/dm-devel/2014-June/msg00033.html

So this needs more review and thought.