Memory Leak?!

[mjman]

Hi,
I just noticed something interesting, which has been happening as of late. When I first boot up my laptop (gentoo-2.6.12-r13) and run free -m, I get ~65 megs of used ram without caches and buffers. This is under E17.
Anyways, After about a day of normal use (firefox, thunderbird, muine, gaim, eclipse, gnome-terminal), if I run free -m again, I get ~500 megs of used ram without caches and buffers! This is with all programs closed except E17 itself.
If I run gnome-system-monitor, and look at the processes, it does not account for this massive ram usage. I can't seem to track down why this is happening. Does anyone have a suggestion of where to look, or why this might be happening?

Thanks,
Mike

[borromini]

Can you try $ ps aux?

[GNOME_n00b]

mjman
firefox is well known to be a memory hog. if you leave it open, it will eat up your RAM.

[mjman]

free reports very high usage even after I close firefox.

I wrote a quick little perl script that totals the RSS and VSZ values from ps, and I get this when I'm running muine and firefox:

rss total: 526 Mb
vsz total: 1073 Mb

This pretty closely agrees with the output from free. However, when I close
firefox and muine, the output from free barely changes, but my script gives:

rss total: 140 Mb
vsz total: 308 Mb

which is much closer to what I would expect. I don't get it...

[GNOME_n00b]

seems to be quite a considerable decrease after you quit firefox. try quitting thunderbird too.

just a wild thought, but are you sure you haven't been hacked (ie ps is giving results that are hiding the tracks of a rootkit). what you've said doesn't say whether you're permanantly connected to the internet and/or running a server etc....so i can only make reasoned guesses.
don't get worried or anything . thats probably not the case, but given the information, i can only speculate.

[mjman]

Just found the culprit!

I took a look in /etc/cron.daily to find that updatedb was running nightly. I rebooted, bringing the mem usage down to ~65 megs. Then, I ran updatedb, and when it finished, the mem usage was at >500 megs, and remained that high after the process stopped.

weird.

[GNOME_n00b]

glad you found the cause . i'm really surprised that updatedb used up that much memory for such a long period. for me, it only runs for about 5 minutes . its quite resource hungry for that 5 minutes, though.

[mjman]

Well the weird thing is that even after updatedb finishes, free and vmstat still claim that the memory is in use. Almost like there is a bug in the kernel that is causing it to reserve memory for a processes that has ended.