linux-kernel - Re: [PATCH 2/2] mm: oom: dump single excessive slab cache when oom

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Message-ID: <20171026162701.re4lclnqkngczpcl@dhcp22.suse.cz>
Date:   Thu, 26 Oct 2017 18:27:01 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Yang Shi <yang.s@...baba-inc.com>
Cc:     cl@...ux.com, penberg@...nel.org, rientjes@...gle.com,
        iamjoonsoo.kim@....com, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] mm: oom: dump single excessive slab cache when oom

On Fri 27-10-17 00:15:17, Yang Shi wrote:
> 
> 
> On 10/26/17 7:53 AM, Michal Hocko wrote:
> > On Thu 26-10-17 06:49:00, Yang Shi wrote:
> > > Per the discussion with David [1], it looks more reasonable to just dump
> > 
> > Please try to avoid external references in the changelog as much as
> > possible.
> 
> OK.
> 
> > 
> > > the single excessive slab cache instead of dumping all slab caches when
> > > oom.
> > 
> > You meant to say
> > "to just dump all slab caches which excess 10% of the total memory."
> > 
> > While we are at it. Abusing calc_mem_size seems to be rather clumsy and
> > tt is not nodemask aware so you the whole thing is dubious for NUMA
> > constrained OOMs.
> 
> Since we just need the total memory size of the node for NUMA constrained
> OOM, we should be able to use show_mem_node_skip() to bring in nodemask.

yes

> > The more I think about this the more I am convinced that this is just
> > fiddling with the code without a good reason and without much better
> > outcome.
> 
> I don't get you. Do you mean the benefit is not that much with just dumping
> excessive slab caches?

Yes, I am not sure it makes sense to touch it without further
experiences. I am not saying this is a wrong approach I would just give
it some more time to see how it behaves in the wild and then make
changes based on that experience.
-- 
Michal Hocko
SUSE Labs