only allowing a certain memory usage

lilmike · 11-21-2009, 11:24 PM

Hi,
I was trying to only allow 6 mb of memory to be used by a certain user's programs.
The program I am most interested in limitting is one that runs in the background.
I set the info in the /etc/security/limits.conf to look like this:
<username> hard rss 6144
I also tried <username> hard memlock 6144
But nothing worked.
He was running about 11.4 percent of my 360 mb, which is much more than 6144 kb, but it didn't kill his task.
Any help on how to stop this and how to limit the programs in the future is appreciated.
-Michael.

imagine_me2 · 11-22-2009, 04:31 AM

Try
$ulimit -m [maxsize]

I dont know exactly if that should fit your purpose.

imagine_me2 · 11-22-2009, 04:32 AM

Try
$ulimit -m [maxsize]

I dont know exactly if that should fit your purpose.

sundialsvcs · 11-22-2009, 02:28 PM

As noted, the ulimit command is useful for imposing limits upon a program that you think might "run away." (Or for testing its operation when you plan to deploy to a shared-host which does impose process limits.)

Also useful is the quota facility.

But bear in mind: when a process "runs away" or is inefficiently designed, "it's never pretty what happens next, on any operating system..."

lilmike · 11-22-2009, 02:52 PM

Hi,
I see what you mean.
However, is there any way to do this with pam?
Also, with ulimit, how do I set it on a per user basis.
And then, I have two users: user1 and user2 let's call them.
User1 has a program called moo.
User2 also has a program called moo.
If I set a memory limit of 6 mb on the user1's moo, will it also impose this limit on user2's moo? for this is not what I want.
Thanks,
-Michael.

lilmike · 11-27-2009, 01:58 PM

Hi,
Does anyone know the answers to the questions asked in the post above?
If you do, then please tell me.
Help is appreciated.
-Michael.

syg00 · 11-27-2009, 04:56 PM

cgroups is an in-kernel solution that is not well documented, and hardly worth the effort on small systems. It is based on the container model, but uses pid for selection. This can make it an administrative burden. I have used it to quarantine certain workloads to a subset of available CPUs, but there is also a memory controller. Recent Ubuntus seem to have the requisite kernel options enabled.
Documented in the kernel source tree at ../Documentation/cgroups - look here for an online copy.