Re: [PATCH RFC] mm: don't raise MEMCG_OOM event due to failed high-order allocation

From: Michal Hocko
Date: Tue Sep 11 2018 - 08:47:42 EST


On Tue 11-09-18 14:41:04, peter enderborg wrote:
> On 09/11/2018 02:11 PM, Michal Hocko wrote:
> > Why is this a problem though? IIRC this event was deliberately placed
> > outside of the oom path because we wanted to count allocation failures
> > and this is also documented that way
> >
> > oom
> > The number of time the cgroup's memory usage was
> > reached the limit and allocation was about to fail.
> >
> > Depending on context result could be invocation of OOM
> > killer and retrying allocation or failing a
> >
> > One could argue that we do not apply the same logic to GFP_NOWAIT
> > requests but in general I would like to see a good reason to change
> > the behavior and if it is really the right thing to do then we need to
> > update the documentation as well.
> >
>
> Why not introduce a MEMCG_ALLOC_FAIL in to memcg_memory_event?

My understanding is that this is what the oom event is about.

--
Michal Hocko
SUSE Labs