Re: Some interesting news about Linux 3.12 OOM

On Sep 24, 2013 10:12 AM, "Josh Berkus" <josh(at)agliodbs(dot)com> wrote:
>
> All,
>
> I've send kernel.org a message that we're keen on seeing these changes
> become committed.

I thought it was merged already in 3.12. There are a few related
patches, but here's one:

commit 519e52473ebe9db5cdef44670d5a97f1fd53d721
Author: Johannes Weiner <hannes(at)cmpxchg(dot)org>
Date: Thu Sep 12 15:13:42 2013 -0700

mm: memcg: enable memcg OOM killer only for user faults

System calls and kernel faults (uaccess, gup) can handle an out of memory
situation gracefully and just return -ENOMEM.

Enable the memcg OOM killer only for user faults, where it's really the
only option available.

Signed-off-by: Johannes Weiner <hannes(at)cmpxchg(dot)org>
Acked-by: Michal Hocko <mhocko(at)suse(dot)cz>
Cc: David Rientjes <rientjes(at)google(dot)com>
Cc: KAMEZAWA Hiroyuki <kamezawa(dot)hiroyu(at)jp(dot)fujitsu(dot)com>
Cc: azurIt <azurit(at)pobox(dot)sk>
Cc: KOSAKI Motohiro <kosaki(dot)motohiro(at)jp(dot)fujitsu(dot)com>
Signed-off-by: Andrew Morton <akpm(at)linux-foundation(dot)org>
Signed-off-by: Linus Torvalds <torvalds(at)linux-foundation(dot)org>

$ git tag --contains 519e52473ebe9db5cdef44670d5a97f1fd53d721
v3.12-rc1
v3.12-rc2

Searching for recent work by Johannes Weiner shows the pertinent stuff
more exhaustively.

> BTW, in the future if anyone sees kernel.org contemplating a patch which
> helps or hurts Postgres, don't hesiate to speak up to them. They don't
> get nearly enough feedback from DB developers.

I don't hesitate, most of the time I simply don't know.