On Thu, 2015-08-20 at 00:52 -0700, Tejun Heo wrote:

Hmmm... I think this discussion got pretty badly derailed at this
point.  If I'm not mistaken, you're talking about tens or a few
hundred millisecs of latency per migration which no longer exists and
won't ever come back and the discussion originally was about something
like migrating thread for issuing several IO requests versus bouncing
that to a dedicated issuer thread in that domain.

Yes, ms latencies ever coming back is the concern, whether that be due
to something akin to the old synchronize_rcu() horror.. or some handoff
of whatever to whomever.

	-Mike