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

On sön, 2011-09-18 at 12:21 -0400, Tom Lane wrote:
> Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> > On fre, 2011-09-16 at 10:57 -0400, Tom Lane wrote:
> >> So it looks like it behooves us to cater for oom_score_adj in the
> >> future. The simplest, least risky change that I can think of is to
> >> copy-and-paste the relevant #ifdef code block in fork_process.c.
> >> If we do that, then it would be up to the packager whether to #define
> >> LINUX_OOM_ADJ or LINUX_OOM_SCORE_ADJ or both depending on the behavior
> >> he wants.
>
> > There are lots of reasons why that won't work: backports, forward ports,
> > derivatives, custom kernels, distribution upgrades, virtual hosting.
>
> [ shrug... ] These are all hypothetical reasons. A packager who
> foresaw needing that could just turn on both write attempts, or for that
> matter patch the code to do whatever else he saw fit. In practice,
> we've not had requests for anything significantly smarter than what is
> there.
>
> 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.