Re: [patch 00/11] userspace out of memory handling

David Rientjes
2014-03-06T21:08:10Z

On Thu, 6 Mar 2014, Tejun Heo wrote:

> > This includes system oom handling alongside memcg oom handling. If you
> > have specific objections, please let us know, thanks!
>
> Umm, that wasn't the bulk of objection, was it? We were discussion
> the whole premise of userland oom handling and the conclusion, at
> best, was that you couldn't show that it was actually necessary and
> most other people disliked the idea.

I'm not sure how you reach that conclusion: it's necessary because any
process handling the oom condition will need memory to do anything useful.
How else would a process that is handling a system oom condition, for
example, be able to obtain a list of processes, check memory usage, issue
a kill, do any logging, collect heap or smaps samples, or signal processes
to throttle incoming requests without having access to memory itself? The
system is oom.

> Just changing a part of it and
> resubmitting doesn't really change the whole situation. If you want
> to continue the discussion on the basic approach, please do continue
> that on the original thread so that we don't lose the context. I'm
> gonna nack the respective patches so that they don't get picked up by
> accident for now.
>

This is going to be discussed at the LSF/mm conference, I believe it would
be helpful to have an actual complete patchset proposed so that it can be
discussed properly. I feel no need to refer to an older patchset that
would not apply and did not include all the support necessary for handling
oom conditions.