Re: [PATCH 0/2] resource control file system - aka containers on top of nsproxy!

Paul Menage
2007-03-09T22:09:53Z

On 3/9/07, Srivatsa Vaddagiri <vatsa@in.ibm.com> wrote:
>
> 1. What is the fundamental unit over which resource-management is
> applied? Individual tasks or individual containers?
>
> /me thinks latter.

Yes

> In which case, it makes sense to stick
> resource control information in the container somewhere.

Yes, that's what all my patches have been doing.

> 2. Regarding space savings, if 100 tasks are in a container (I dont know
> what is a typical number) -and- lets say that all tasks are to share
> the same resource allocation (which seems to be natural), then having
> a 'struct container_group *' pointer in each task_struct seems to be not
> very efficient (simply because we dont need that task-level granularity of
> managing resource allocation).

I think you should re-read my patches.

Previously, each task had N pointers, one for its container in each
potential hierarchy. The container_group concept means that each task
has 1 pointer, to a set of container pointers (one per hierarchy)
shared by all tasks that have exactly the same set of containers (in
the various different hierarchies).

It doesn't give task-level granularity of resource management (unless
you create a separate container for each task), it just gives a space
saving.

>
> 3. This next leads me to think that 'tasks' file in each directory doesnt make
> sense for containers. In fact it can lend itself to error situations (by
> administrator/script mistake) when some tasks of a container are in one
> resource class while others are in a different class.
>
> Instead, from a containers pov, it may be usefull to write
> a 'container id' (if such a thing exists) into the tasks file
> which will move all the tasks of the container into
> the new resource class. This is the same requirement we
> discussed long back of moving all threads of a process into new
> resource class.

I think you need to give a more concrete example and use case of what
you're trying to propose here. I don't really see what advantage
you're getting.

Paul