cgconfig.conf

group gotools {
  perm {
    admin {
      uid = UID;
      gid = UID;
    }
    task {
      uid = UID;
      gid = UID;
    }
  }
  cpu {
    cpu.shares = 256;
  }
  memory {
# limit to 6GB
    memory.limit_in_bytes = 6442450944;
  }
}
~

gopls.bash

#!/bin/bash

cgexec \
  -g memory,cpu:gotools \
  $GOPATH/bin/gopls.real "$@"

setup.example

$ sudo apt install cgroup-tools
$ mv cgconfig.conf /etc/cgconfig.conf
$ sed -i -e 's|UID|$(id -u)|' /etc/cgconfig.conf
$ sudo cgconfigparser -l /etc/cgconfig.conf
$ mv $GOPATH/bin/gopls $GOPATH/bin/gopls.real
$ ln -sf /path/to/gopls.bash $GOPATH/bin/gopls

Also worth noting, to get the most mileage out of this you will probably have to configure your editor to pass the --remote=auto option to gopls.