First enter this command, to check your current setting:
sysctl vm.min_free_kbytes
To change the set value:
sudo nano /etc/sysctl.conf
Look for this line:
vm.min_free_kbytes=12888
If it doesn't exist, create it (along with your desired value).
The following values are acceptable
8192 12288 16384 20480
8M is extremely conservative and can sit at 16M comfortably.
Once you change the value, run this and no reboot is needed.
sudo sysctl -p