Cgroups – How to Limit Memory Per User

cgroup

Is it possible to limit memory usage per user not per group?

This is my config …

/etc/cgconfig.conf

mount {
    cpu     = /cgroup/cpu_and_mem;
    cpuacct = /cgroup/cpu_and_mem;
    memory  = /cgroup/cpu_and_mem;
}
group small {
        cpu {
                cpu.shares="100";
        }
        cpuacct {
                cpuacct.usage="0";
        }
        memory {
                memory.limit_in_bytes="200M";
                memory.memsw.limit_in_bytes="200M";
        }
}

/etc/cgrules.conf

@guests      cpu,cpuacct,memory      small
user1        cpu,cpuacct,memory      small
user2        cpu,cpuacct,memory      small

Right now i see only one option to create group small1 and link user1 to that group, then user2 to small2 and so on, like this:

/etc/cgconfig.conf

group small1 {
        cpu {
                cpu.shares="100";
...
group small2 {
        cpu {
                cpu.shares="100";
...

/etc/cgrules.conf

user1        cpu,cpuacct,memory      small1
user2        cpu,cpuacct,memory      small2

Does anybody know better way of doing this?

Best Answer

Is it possible to limit memory usage per user not per group?

It is possible with templates

Rules specified in /etc/cgrules.conf can be linked to templates configured either in the /etc/cgconfig.conf file or in configuration files stored in the /etc/cgconfig.d/ directory, allowing for flexible cgroup assignment and creation.

Related Solutions

Linux – How to create and use Linux cgroups as a non-root user

You can't do that as a normal user. But you can setup a cgroup as root, and make it configurable by your user.

If you do not already have the default cgroups controllers mounted by e.g. systemd:

$ sudo mount -t tmpfs cgroup_root /sys/fs/cgroup
$ sudo mkdir /sys/fs/cgroup/cpuset
$ sudo mount -t cgroup -o cpuset cpuset /sys/fs/cgroup/cpuset

Create a cgroup:

$ sudo mkdir /sys/fs/cgroup/cpuset/${USER}
$ sudo chown -R ${USER} /sys/fs/cgroup/cpuset/${USER}

You can now modify the configuration of your cgroup as a normal user:

$ echo 0-3 > /sys/fs/cgroup/cpuset/${USER}/cpuset.cpus

Add a process to that group:

$ ./my_task &
$ echo $! > /sys/fs/cgroup/cpuset/${USER}/tasks

Or create a subgroup:

$ mkdir /sys/fs/cgroup/cpuset/${USER}/subgroup
$ echo 0-1 > /sys/fs/cgroup/cpuset/${USER}/subgroup/cpuset.cpus
$ ./my_other_task &
$ echo $! > /sys/fs/cgroup/cpuset/${USER}/subgroup/tasks

Cgroup – Limit Private Memory Usage Per User

Posting what I think might be a better answer.

My requirement is preventing one user's runaway process(es) from crashing the entire system.

Linux already has a feature for doing exactly this: the OOM killer.

The OOM killer runs when the system runs out of memory, and favors processes that consume a lot of RAM quickly. It is also less likely to kill long-running / system (superuser) processes.

The OOM killer can be further tuned by tweaking the /proc/<pid>/oom_score_adj file. The setting is inherited by child processes, so you only need to set it on each user's root process. (See Documentation/filesystems/proc.txt, section 3.1)

Best Answer

Related Solutions

Linux – How to create and use Linux cgroups as a non-root user

Cgroup – Limit Private Memory Usage Per User

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