Re: [RFD] cgroup: about multiple hierarchies

[Peter Zijlstra <peterz@infradead.org>]

On Tue, 2012-02-28 at 16:54 -0500, Vivek Goyal wrote:
> On Tue, Feb 28, 2012 at 10:43:54PM +0100, Peter Zijlstra wrote:
> > On Tue, 2012-02-28 at 16:35 -0500, Vivek Goyal wrote:
> > > For
> > > cpu controller, it is priority at the group level no fixed minimum/maximum
> > > % shares. And that's a limitation of treating task and group at same level.
> > 
> > Depends on what you mean by min/max %, you can do it on the group level
> > by using bandwidth caps (for max) or inverted (max on everybody else,
> > for min).
> 
> I was referring to using pure proportional controller. max bandwidth is
> new and I am looking for a quick documentation file which describes
> what are the knobs and how to use it. Did not find any in
> Documentation/cgroups/. Is there any documentation available?

Its written in C, its at kernel/sched/fair.c ;-)

> I am assuming that max are being specified for groups in some absolute
> quantity. That is fine. It will not still be max %, as again for % you
> need fixed number of entities at any level and that's not the case with
> tasks.
> 
> Minimum for one group (max for everyone else) will also only work if 
> task and groups are not at same level.

I'm really not seeing this.

> I think the only way to get fixed % share is not to put task and group
> at same level during system configuration.

Still doesn't matter, like said, its all runnable based. If a group has
0 runnable entities it doesn't exist (more or less).