Re: Panic on OOM

From: KAMEZAWA Hiroyuki
Date: Tue Jun 14 2011 - 20:48:18 EST


On Tue, 14 Jun 2011 09:31:16 -0400
Chris Fowler <cfowler@xxxxxxxxxxxxxxxxxxx> wrote:

> I'm running into a problem in 2.6.38 where the kernel is not doing what
> I'm expecting it to do. I'm guessing that some things have changed and
> that is what it going on.
>
> First, The tune at boot:
>
> f.open("/proc/sys/vm/panic_on_oom", std::ios::out);
> f << "1";
> f.close();
>
> f.open("/proc/sys/kernel/panic", std::ios::out);
> f << "10";
> f.close();
>
> I want the kernel to panic on out of memory. I then want it to wait 10s
> before doing a reboot.
>
> This program will consume all memory and make the box unresponsive
>
> #!/usr/bin/perl
>
> my @mem = ()
> while(1) {
> push @mem, "########################";
> }
>

Hmm, then, OOM-Killer wasn't invoked ?

> It does not take long to fill up 1G of space. There is NO swap on this
> device and never will be. I did notice that after a long period of time
> (I've not timed it) I finally do see a panic and I do see "rebooting in
> 10 seconds..." . It does not reboot.
>

In these month(after 2.6.38), there has been some discussion
that "oom-killer doesn't work enough or lru scan very slow" problem
in linux-mm list. (and some improvemetns have been done.)

Then, if you can post your 'test case' with precise description of
machine set up, we're glad.

>
> I'm guessing that there are some tweaks or new behavior I just need to
> be aware of.
>

What version of kernel did you used in previous setup ?

Thanks,
-Kame








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