Date: Wed, 2 Jul 2014 09:08:10 -0400
From: Jonathan Corbet <corbet@lwn.net>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Christoph Berg <cb@df7cb.de>, Tom Lane <tgl@sss.pgh.pa.us>, Gurjeet
 Singh <gurjeet@singh.im>, 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
Message-ID: <20140702090810.73c5572d@lwn.net>
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On Tue, 1 Jul 2014 15:57:25 -0400
Robert Haas <robertmhaas@gmail.com> wrote:

> Of course, we have no guarantee that the Linux kernel guys won't
> change this again.  Apparently "we don't break userspace" is a
> somewhat selectively-enforced principle.

It's selectively enforced in that kernel developers don't (and can't)
scan the world for software that might break.  OTOH, if somebody were
to respond to a proposed change by saying "this breaks PostgreSQL," I
would be amazed if the change were to be merged in that form.

In other words, it's important to scream.  There were concerns during
the last round of messing with the OOM logic, but nobody pointed to
something that actually broke.

I predict that somebody will certainly try to rewrite the OOM code
again in the future.  The nature of that code is such that it is never
going to work as well as people would like.  But if application
developers make it clear that they are dependent on the current
interface working, kernel developers will be constrained to keep it
working.

jon


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