[rhelv6-list] Kernel memory leak?

Chris Adams cmadams at hiwaay.net
Sat Jan 22 04:06:54 UTC 2011

Once upon a time, Stephen John Smoogen <smooge at gmail.com> said:
> > I looked at "slabtop", and the dentry cache is the culprit:
> >
> > 3078900 3078900 100%    0.19K 153945       20    615780K dentry
> >
> > Anybody else seeing this?
> What is the box doing? How is it set up (ext3, ext4, ?). I haven't
> really looked but would want to check with a system that is set up
> similarly.

It is running ext4 on LVM on md-raid1.  It is running Nagios, Apache,
Quagga, Network UPS Tools (monitoring a couple of UPSes), and smstools.
Quagga is running OSPF (to learn some routes to some of the
Nagios-monitored devices) and BGP (to advertise some routes via BGP from
a home-written "bad IP" monitor).

The bad-IP monitor uses several perl scripts I wrote, one of which uses
the Linux::Inotify2 module to watch a directory that gets log files
added and removed for each bad IP.  The last few days have been rather
busy for my bad IP detector; there are 1292 files in that directory
right now for the last 48 hours.

I wondered if the single inotify could be a trigger (as that's the only
thing really unusual), but stopping that daemon doesn't free the RAM
from the dentry cache.

This same set of software was running on the old server (running Fedora
7 i386 - yes, I was that far behind).  It was different hardware, but
the same setup except for ext3 instead of ext4 (still LVM on md-raid1,
Nagios, Apache, etc.).  The old server's RAM usage had been level for
years at 256M RAM; the new server started at about 512M (not unexpected
since I switched to x86_64) and has increased in an almost perfectly
straight line to just under 1G in 8 days.

The only other difference from the old server is that it had SELinux
disabled and the new one has SELinux running in permissive mode (still
trying to work on a useful policy to allow Nagios to do all the things I

Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

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