I'm running Ubuntu 18.04.2 LTS and JanKanis script doesn't work for me quite as he suggests. Running limitmem 100M script is limiting 100MB of RAM with unlimited swap.
Running limitmem 100M -s 100M script fails silently as cgget -g "memory:$cgname" has no parameter named memory.memsw.limit_in_bytes.
So I disabled swap:
# create cgroup
sudo cgcreate -g "memory:$cgname"
sudo cgset -r memory.limit_in_bytes="$limit" "$cgname"
sudo cgset -r memory.swappiness=0 "$cgname"
bytes_limit=`cgget -g "memory:$cgname" | grep memory.limit_in_bytes | cut -d\ -f2`
Hope this helps someone.