Re: /proc/self/oom_adj is deprecated in newer Linux kernels

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels
Date: 2012-06-12 17:05:18
Message-ID: 18875.1339520718@sss.pgh.pa.us
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Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Jun 12, 2012 at 12:37 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I still think it's sufficient to do what I suggested initially:
>>> ... The simplest, least risky change that I can think of is to
>>> copy-and-paste the relevant #ifdef code block in fork_process.c.

> I think my position, and the position of the people who responded to
> the original thread, was that it seems like you're architecting a
> kludge when it wouldn't be that hard to architect a nicer solution.

I'd be the first to agree it's a kluge. But the end result of the
previous discussion was that it wasn't so obvious how to architect
a nicer solution. Nor is there all that much room for people to use a
nicer solution, given that we need help from not just fork_process.c
but the root-privileged startup script (or lately in Fedora it's a
systemd unit script doing the privilege-increasing end of this).

In the short run, if we don't have consensus on this, I'll probably
just carry a Fedora patch like so:

- int fd = open("/proc/self/oom_adj", O_WRONLY, 0);
+ int fd = open("/proc/self/oom_score_adj", O_WRONLY, 0);

But it seems a tad silly to be carrying such a patch for a block of
code that is only of interest to Linux packagers anyway, and nearly
all such packagers are facing this same issue either now or in the
very near future.

regards, tom lane

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