Re: [patch 2/2] cpusets: add interleave_over_allowed option

David Rientjes
2007-10-26T02:45:53Z

On Thu, 25 Oct 2007, Paul Jackson wrote:

> Are you seeing this in a real world situation? Can you describe the
> situation? I don't mean just describing how it looks to this kernel
> code, but what is going on in the system, what sort of job mix or
> applications, what kind of users, ... In short, a "use case", or brief
> approximation thereto. See further:
>

Yes, when using cpusets for resource control. If memory pressure is being
felt for that cpuset and additional mems are added to alleviate possible
OOM conditions, it is insufficient to allow tasks within that cpuset to
continue using memory policies that prohibit them from taking advantage of
the extra memory.

The best remedy for that situation is to give the cpuset owner the option
of allowing tasks with MPOL_INTERLEAVE policies to always interleave over
the entire set of available mems so they can be dynamically expanded and
contracted at will without triggering OOM conditions.

> Do you have a link to what Lee proposed? I agree that a full general
> solution would seem to require a new or changed set_mempolicy API,
> which may well be more than we want to do, absent a more compelling
> "use case" requiring it than we have now.
>