Re: [RFC] cgroup TODOs

[Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

Hello,

On Wed, Sep 19, 2012 at 06:33:15PM -0700, Andy Lutomirski wrote:
> [grr.  why does gmane scramble addresses?]

You can append /raw to the message url and see the raw mssage.

  http://article.gmane.org/gmane.linux.kernel.containers/23802/raw

> >   I think this level of flexibility should be enough for most use
> >   cases.  If someone disagrees, please voice your objections now.
> 
> OK, I'll bite.
> 
> I have a server that has a whole bunch of cores.  A small fraction of
> those cores are general purpose and run whatever they like.  The rest
> are tightly controlled.
> 
> For simplicity, we have two cpusets that we use.  The root allows all
> cpus.  The other one only allows the general purpose cpus.  We shove
> everything into the general-purpose-only cpuset, and then we move
> special stuff back to root.  (We also shove some kernel threads into a
> non-root cpuset using the 'cset' tool.)

Using root for special stuff probably isn't a good idea and moving
bound kthreads into !root cgroups is already disallowed.

> Enter systemd, which wants a hierarchy corresponding to services.  If we
> were to use it, we might end up violating its hierarchy.
> 
> Alternatively, if we started using memcg, then we might have some tasks
> to have more restrictive memory usage but less restrictive cpu usage.
> 
> As long as we can still pull this off, I'm happy.

IIUC, you basically want just two groups w/ cpuset and use it for
loose cpu ioslation for high priority jobs.  Structure-wise, I don't
think it's gonna be a problem although using root for special stuff
would need to change.

Thanks.

-- 
tejun