Bug#270735: exim4: Self-denial of mail service

Andreas Metzler Andreas Metzler <eximusers@downhill.at.eu.org>, 270735@bugs.debian.org
Mon, 13 Sep 2004 08:43:04 +0200


On 2004-09-12 Greg Kochanski <gpk@kochanski.org> wrote:
> Stephen Gran wrote:
> >This one time, at band camp, Andreas Metzler said:

> >>Should exim really have that fine grained knowledge for a specific
> >>target platform (detect "when the free RAM is small and the system is
> >>starting to swap") built in?

>> Absolutely not - that's what the kernel VM is for.  The kernel VM (at
>> least on linux) will hold as much of an app in memory as possible, and
>> swap it out if it needs to free up some memory.  Sometimes all of the
>> memory is actively being used, and the kernel has to resort to the OOM
>> killer.  How could exim possibly know whether or not memory being used
>> is able to be swapped out, or whether it is in active use?

> How?   It looks in /proc/meminfo .
[...]

login__~> cat /proc/meminfo
cat: 0652-050 Cannot open /proc/meminfo.
login__~> uname -a
AIX login 2 5 00404A0A4C00

The existence of /proc and the files in it are OS-specific. And not
only the files itself but also the required data (different OS will
require different algoritms for detecting a pending OOM condition).
                    cu andreas
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