Messages in this thread | | | Date | Mon, 23 Jan 2012 07:57:45 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH 08/17] blkcg: shoot down blkio_groups on elevator switch |
| |
On Mon, Jan 23, 2012 at 10:52:16AM -0500, Vivek Goyal wrote: > Atleast throttling rules should not disappear over elevator switch. They > are per device and not per IO scheduler. Think of losing nr_requests > settings just because elevator switch happened. > > Elevator switch can be low frequency but how would a user space know > that elevator switch failed that's why we lost our rules and now lets > put the rules back.
It's simple - store all the policy rules before switching elevators and restore them afterwards regardless of success / failure.
> I am not sure how would we justify this that because of ease of programming > in kernel, now user space is supposed to make sure that any programmed > rules are still there and reprogram the cgroup if rules are gone for > some reason.
Sanity in trade off?
-- tejun
| |