[Devel] Re: [PATCH 6/7] containers (V7): BeanCounters over generic process containers

[Paul Menage]

On 2/13/07, Pavel Emelianov <xemul at sw.ru> wrote:
> menage at google.com wrote:
> > This patch implements the BeanCounter resource control abstraction
> > over generic process containers. It contains the beancounter core
> > code, plus the numfiles resource counter. It doesn't currently contain
> > any of the memory tracking code or the code for switching beancounter
> > context in interrupts.
>
> Numfiles is not the most interesting place in beancounters.
> Kmemsize accounting is much more important actually.

Right, but the memory accouting was a much bigger and more intrusive
patch than I wanted to include as an example.

>
> I have already pointed out the fact that this place
> will hurt performance too much. If we have some context
> on task this context must
>   1. be get-ed without any locking

Would you also be happy with the restriction that a task couldn't be
moved in/out of a beancounter container by any task other than itself?
If so, the beancounter can_attach() method could simply return false
if current != tsk, and then you'd not need to worry about locking in
this situation.

>   2. be settable to some temporary one without
>      locking as well

I thought that we solved that problem by having a tmp_bc field in the
task_struct that would take precedence over the main bc if it was
non-null?

Paul