Hello,

On Mon, Sep 17, 2012 at 11:05:18AM -0400, Vivek Goyal wrote:

As a developer, I will be happy to support only one model and keep code
simple. I am only concerned that for blkcg we have still not charted
out a clear migration path. The warning message your patch is giving
out will work only if we decide to not treat task and groups at same
level.

It may not be enough but it still is in the right direction.

quoted

Another problem is that configuration isn't contained in cgroup
proper.  We need a way to assign weights to individual tasks which can
be somehow directly compared against group weights.  cpu cooks
priority for this and blkcg may be able to cook ioprio but it's nasty
and unobvious.  Also, let's say we grow network bandwidth controller
for whatever reason.  What value are we gonna use?

So if somebody cares about settting SO_PRIORITY for traffic originating
from a tasks, move it into a cgroup. Otherwise they all get default
priority.

I don't know.  Do we wanna add, say, prctl for memory weight too?

So to me, leaving this decision to userspace based on their requirement
makes sense.

Leaving too many decisions to userland is one of the reasons that got
us into this mess, so I'm not sold on flexibility for flexibility's
sake.

Yes, creating a hidden group for tasks in current group should not be
hard from implementation point of view. But again, I am concerned about
configuration of hidden group and I also don't like the idea of taking
flexibility away from user to treat tasks and group at same level.

I don't know.  Create a reserved directory for it?  I do like the idea
of taking flexibility away form user unless it's actually useful but
am a bit worried we might be too late for that. :(

Thanks.

-- 
tejun