Re: [v8 0/4] cgroup-aware OOM killer

[Michal Hocko]

On Mon 25-09-17 19:15:33, Roman Gushchin wrote:
[...]
> I'm not against this model, as I've said before. It feels logical,
> and will work fine in most cases.
> 
> In this case we can drop any mount/boot options, because it preserves
> the existing behavior in the default configuration. A big advantage.

I am not sure about this. We still need an opt-in, ragardless, because
selecting the largest process from the largest memcg != selecting the
largest task (just consider memcgs with many processes example).

> The only thing, I'm slightly concerned, that due to the way how we calculate
> the memory footprint for tasks and memory cgroups, we will have a number
> of weird edge cases. For instance, when putting a single process into
> the group_oom memcg will alter the oom_score significantly and result
> in significantly different chances to be killed. An obvious example will
> be a task with oom_score_adj set to any non-extreme (other than 0 and -1000)
> value, but it can also happen in case of constrained alloc, for instance.

I am not sure I understand. Are you talking about root memcg comparing
to other memcgs?
-- 
Michal Hocko
SUSE Labs