How to Limit Memory Usage per User

Using ulimit

sudo nano /etc/security/limits.conf

Add:

username soft as 1048576   # 1GB in KB
username hard as 2097152   # 2GB

Also for RSS:

username soft rss 1048576

Using cgroups memory controller

sudo mkdir /sys/fs/cgroup/memory/user1
echo 1G > /sys/fs/cgroup/memory/user1/memory.limit_in_bytes
echo [PID] > /sys/fs/cgroup/memory/user1/cgroup.procs

Check memory usage per user

sudo smem -u