Oh Bugger, part 3: Memory leaks suck

[unixronin]

I appear to have just confirmed I have a kernel memory leak on this machine.

Before reboot:  496M of physical RAM out of 512M in use for processes, 300M of swap out of 512M used, total of around 850M of RAM usage and only 50M of it buffers and cache.  After reboot:  295M of physical RAM used for processes, 210M used for buffers and cache, zero swap used.  Same processes running, same number of browser windows open to the same pages, same four processes are the top memory users, they're still the only ones using over 1M of RAM, and they're using about the same amount as they were before rebooting.

So somewhere, the kernel had leaked half a gig of RAM....

Comments

[unixronin.livejournal.com]

You said "same number of browser windows open to the same pages" which strongly suggests a lack of due diligence before claiming a kernel memory leak, because you were still running gods know how many user processes.

Yeah, that was poor wording on my part. I should probably have added "as were running before I started trying to troubleshoot the leak". I'd started all my userspace environment back up again to try and make as fair as possible a comparison.

You are in fact right, I hadn't exhausted all possibilities; although I'd shut down and restarted pretty much everything running outside the kernel, I hadn't done so to all of them SIMULTANEOUSLY by dropping to single-user. (I basically don't keep any non-essential kernel modules loaded except for my sound drivers, and I'd already ascertained that the sound subsystem is not the problem.) GP's suggestion that it was a library leaking memory hadn't occurred to me, and after looking a little further, this is now looking like a very real possibility. Furthermore, I suspect there's a high likelihood it's one of the Gnome2 libraries that I had to update a few weeks ago in order to support software dependencies for the latest Firefox releases.

This machine is, frankly, overdue for a totally clean reinstall of a current version of the OS. Last time I tried to do this, about a year ago, was with Slackware 9, which turned out to be so badly broken it wouldn't work. I suspect a clean new OS image will clean up a number of nagging problems.