Date: Mon, 25 Sep 2017 16:23:52 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Yang Shi <yang.s@alibaba-inc.com>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
        iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2 v4] oom: capture unreclaimable slab info in oom
 message when kernel panic
Message-ID: <20170925142352.havlx6ikheanqyhj@dhcp22.suse.cz>
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On Thu 21-09-17 06:38:50, Yang Shi wrote:
> Recently we ran into a oom issue, kernel panic due to no killable process.
> The dmesg shows huge unreclaimable slabs used almost 100% memory, but kdump doesn't capture vmcore due to some reason.
> 
> So, it may sound better to capture unreclaimable slab info in oom message when kernel panic to aid trouble shooting and cover the corner case.
> Since kernel already panic, so capturing more information sounds worthy and doesn't bother normal oom killer.
> 
> With the patchset, tools/vm/slabinfo has a new option, "-U", to show unreclaimable slab only.
> 
> And, oom will print all non zero (num_objs * size != 0) unreclaimable slabs in oom killer message.

Well, I do undestand that this _might_ be useful but it also might
generates a _lot_ of output. The oom report can be quite verbose already
so is this something we want to have enabled by default?
-- 
Michal Hocko
SUSE Labs