To: Peter Eisentraut <peter_e@gmx.net>
cc: pgsql-hackers@postgreSQL.org
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels 
In-reply-to: <1316420754.14001.3.camel@fsopti579.F-Secure.com> 
References: <29121.1316185073@sss.pgh.pa.us>
	<1316355543.12186.9.camel@vanquo.pezone.net>
	<15953.1316362868@sss.pgh.pa.us>
	<1316420754.14001.3.camel@fsopti579.F-Secure.com>
Comments: In-reply-to Peter Eisentraut <peter_e@gmx.net>
	message dated "Mon, 19 Sep 2011 11:25:54 +0300"
Date: Mon, 19 Sep 2011 10:18:03 -0400
Message-ID: <16241.1316441883@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Peter Eisentraut <peter_e@gmx.net> writes:
> On sön, 2011-09-18 at 12:21 -0400, Tom Lane wrote:
>> But having said that, it wouldn't be very hard to arrange things so that
>> if you did have both symbols defined, the code would only attempt to
>> write oom_adj if it had failed to write oom_score_adj; which is about as
>> close as you're likely to get to a kernel version test for this.

> Why is this feature not a run-time configuration variable or at least a
> configure option?  It's awfully well hidden now.  I doubt a lot of
> people are using this even though they might wish to.

See the thread in which the feature was designed originally:
http://archives.postgresql.org/pgsql-hackers/2010-01/msg00170.php

The key point is that to get useful behavior, you need cooperation
between both a root-privileged startup script and the PG executable.
That tends to throw the problem into the domain of packagers, more
than end users, and definitely puts a big crimp in the idea that
run-time configuration of just half of the behavior could be helpful.
So far, no Linux packagers have complained that the design is inadequate
(a position that I also hold when wearing my red fedora) so I do not
feel a need to complicate it further.

			regards, tom lane