Re: any way to find out kernel memory usage?

From: Richard B. Johnson
Date: Wed Apr 27 2005 - 13:36:01 EST

On Wed, 27 Apr 2005, Coywolf Qi Hunt wrote:

On 4/28/05, Chris Friesen <cfriesen@xxxxxxxxxx> wrote:

We recently had an issue with a kernel module leaking memory on unload,
and a userspace app that unloaded it way too many times.

This ended up using up a bunch of memory, which triggered the oom-killer
to run, which went wild killing everything in sight since userspace
wasn't actually the culprt.

One idea we had to prevent this in the future is to configure the OOM
killer to reset the system if the kernel uses more than a certain amount
of memory. (Reset is better than hang for our purposes.) Is there any

Curiously, how to reset? Reboot? (Teach oom killer to kill) or restart
the related
kernel thread?

In user-mode code... `man 2 reboot` tells all.
Quickest way in kernel mode on ix86 is a processor reset.

way to find out how much memory the kernel is using? I don't see
anything in /proc, but maybe something internal that isn't currently


In the kernel nr_free_pages() <swap.h> gives you a hint of what's left,
num_physpages() tells you what RAM you started with.

Dick Johnson
Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips).
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