Cgroups v2 - limit memory and CPU usage for all users on Linux

Posted by Pavlo Khmel on Thu 01 February 2024

Starting with systemd v239 it is more easy to set cgroups limits for all users on a system.

This is an example of setting a memory limit of 30GB and CPU usage equivalent to 8 x 100% loaded CPUs:

# mkdir -p /etc/systemd/system/user-.slice.d

# cat /etc/systemd/system/user-.slice.d/50-memory.conf
[Slice]
MemoryMax=30G
CPUQuota=800%

# systemctl daemon-reload

NOTE: Use values > 100% for allotting CPU time on more than one CPU.

Limits will be applied immediately.

Check applied limits. Get any logged-in user UID with "id" command.

$ cat /sys/fs/cgroup/user.slice/user-[UID].slice/memory.max
32212254720

$ cat /sys/fs/cgroup/user.slice/user-[UID].slice/cpu.max
800000 100000

Useful links: https://github.com/systemd/systemd/commit/5396624506e155c4bc10c0ee65b939600860ab67 https://www.freedesktop.org/software/systemd/man/latest/systemd.resource-control.html