From: Tom Lane <tgl@sss.pgh.pa.us>
To: Gurjeet Singh <gurjeet@singh.im>
cc: Andres Freund <andres@anarazel.de>, Peter Eisentraut <peter_e@gmx.net>,
 PGSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels
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Comments: In-reply-to Gurjeet Singh <gurjeet@singh.im>
 message dated "Tue, 10 Jun 2014 11:58:01 -0400"
Date: Tue, 10 Jun 2014 12:05:56 -0400
Message-ID: <31652.1402416356@sss.pgh.pa.us>
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Sender: pgsql-hackers-owner@postgresql.org

Gurjeet Singh <gurjeet@singh.im> writes:
> On Tue, Jun 10, 2014 at 11:52 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Robert's idea of having the start script set an environment variable to
>> control the OOM adjustment reset seems like it would satisfy my concern.

> I'm fine with this solution. Should this be a constant 0, or be
> configurable based on env. variable's value?

If we're going to do this, I would say that we should also take the
opportunity to get out from under the question of which kernel API
we're dealing with.  So perhaps a design like this:

1. If the environment variable PG_OOM_ADJUST_FILE is defined, it's
the name of a file to write something into after forking.  The typical
value would be "/proc/self/oom_score_adj" or "/proc/self/oom_adj".
If not set, nothing happens.

2. If the environment variable PG_OOM_ADJUST_VALUE is defined, that's
the string we write, otherwise we write "0".

			regards, tom lane


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