linux-kernel - Re: [RFC PATCH] mm, oom: disable dump

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Date:   Wed, 4 Sep 2019 13:04:04 -0700 (PDT)
From:   David Rientjes <rientjes@...gle.com>
To:     Michal Hocko <mhocko@...nel.org>
cc:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH] mm, oom: disable dump_tasks by default

On Wed, 4 Sep 2019, Michal Hocko wrote:

> > > It's primary purpose is
> > > to help analyse oom victim selection decision.
> > 
> > I disagree, for I use the process list for understanding what / how many
> > processes are consuming what kind of memory (without crashing the system)
> > for anomaly detection purpose. Although we can't dump memory consumed by
> > e.g. file descriptors, disabling dump_tasks() loose that clue, and is
> > problematic for me.
> 
> Does anything really prevent you from enabling this by sysctl though? Or
> do you claim that this is a general usage pattern and therefore the
> default change is not acceptable or do you want a changelog to be
> updated?
> 

I think the motivation is that users don't want to need to reproduce an 
oom kill to figure out why: they want to be able to figure out which 
process had higher than normal memory usage.  If oom is the normal case 
then they ceratinly have the ability to disable it by disabling the 
sysctl, but that seems like something better to opt-out of rather than 
need to opt-in to and reproduce.