[Devel] Re: [ckrm-tech] [PATCH] BC: resource beancounters (v4) (added user memory)

[Rohit Seth]

On Mon, 2006-09-11 at 11:25 -0700, Chandra Seetharaman wrote:
> On Fri, 2006-09-08 at 14:43 -0700, Rohit Seth wrote:
> <snip>
> 
> > > > Guarantee may be one of
> > > > 
> > > >   1. container will be able to touch that number of pages
> > > >   2. container will be able to sys_mmap() that number of pages
> > > >   3. container will not be killed unless it touches that number of pages
> > > >   4. anything else
> > > 
> > > I would say (1) with slight modification
> > >    "container will be able to touch _at least_ that number of pages"
> > > 
> > 
> > Does this scheme support running of tasks outside of containers on the
> > same platform where you have tasks running inside containers.  If so
> > then how will you ensure processes running out side any container will
> > not leave less than the total guaranteed memory to different containers.
> > 
> 
> There could be a default container which doesn't have any guarantee or
> limit. 

First, I think it is critical that we allow processes to run outside of
any container (unless we know for sure that the penalty of running a
process inside a container is very very minimal).

And anything running outside a container should be limited by default
Linux settings.

> When you create containers and assign guarantees to each of them
> make sure that you leave some amount of resource unassigned. 
                           ^^^^^ This will force the "default" container
with limits (indirectly). IMO, the whole guarantee feature gets defeated
the moment you bring in this fuzziness.

> That
> unassigned resources can be used by the default container or can be used
> by containers that want more than their guarantee (and less than their
> limit). This is how CKRM/RG handles this issue.
> 
>  

It seems that a single notion of limit should suffice, and that limit
should more be treated as something beyond which that resource
consumption in the container will be throttled/not_allowed.

-rohit