Re: oom_killer

On Fri, Apr 22, 2011 at 11:15 AM, David Rees <drees76(at)gmail(dot)com> wrote:
> On Thu, Apr 21, 2011 at 1:28 AM, Tory M Blue <tmblue(at)gmail(dot)com> wrote:
>> this is a Fedora 12 system, 2.6.32.23-170. I've been reading and
>> appears this is yet another fedora bug, but so far I have not found
>> any concrete evidence on how to fix it.
>
> If it's a "fedora" bug, it's most likely related to the kernel where
> the OOM-killer lives which really makes it more of a kernel bug than a
> fedora bug as fedora kernels generally track upstream very closely.
>
> Given that both the version of Fedora you're using is no longer
> supported, at a minimum you should be running F-13 (or preferably F-14
> since F-13 will lose maintenance in appx 2 months).  If you have to
> stay on F-12 you might at least try building the latest
> 2.6.32-longterm kernel which is up to version 2.6.32.39.
>
> All that said - have you tried tracking memory usage of the machine
> leading up to OOM killer events?
>

Thanks David and I have and in fact I do see spikes that would cause
my system to run out of memory, but one thing I'm struggling with is
my system always runs at the limit. It's the nature of linux to take
all the memory and manage it. The larger hurdle is why no swap is ever
used, it's there, but the system never uses it. even the oom killer
shows that I have the full 5gb of swap available, yet nothing is using
is. I want want want to see swap being used!

If I run a script to do a bunch of malocs and hold I can see the
system use up available memory then lay the smack down on my swap
before oom is invoked.

So I'm starting to think in the meantime, while I rebuild, I need to
make sure I've got my postgres/kernel params in a good place. my ratio
of 0 still allows oom_killer, but I've removed postgres from being
targeted by oom_killer now. I should still set the overcommit ratio
correct for my 32gb 4-5gb swap system, but having a hard time wrapping
my head around that setting.

Tory