Re: [patch -mm 5/5] oom: add sysctl to dump tasks memory state

[Andrew Morton <akpm@linux-foundation.org>]

On Sat, 22 Sep 2007 10:47:13 -0700 (PDT)
David Rientjes <rientjes@google.com> wrote:

> Adds a new sysctl, 'oom_dump_tasks', that dumps a list of all system tasks
> (excluding kernel threads) and their pid, uid, tgid, vm size, rss cpu,
> oom_adj score, and name.
> 
> Helpful for determining why an OOM condition occurred and what rogue task
> caused it.
> 
> It is configurable so that large systems, such as those with several
> thousand tasks, do not incur a performance penalty associated with data
> they may not desire.
> 
> There currently do not appear to be any other generic kernel callers that
> dump all this information.  Perhaps in the future it will be worthwhile
> to construct a generic task dump interface based on passing a set of
> flags that specify what per-task information shall be shown.

It isn't obvious to me why this has "oom" in its name.  It is just a
general display-stuff-about-task-memory handler, isn't it?

Nor is it obvious why we need it at all.  This sort of information can
already be gathered from /proc/pid/whatever.  If the system is all wedged
and you can't get console control then this info dump doesn't provide you
with info which you're interested in anyway - you want to see the global
(or per-cgroup) info, not the per-task info.

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