I have been playing around with a couple of modules and monitoring their memory usage. I wanted to clear the caches and buffers to give me a clearer picture of memory usage.
This command is handy for clearing them out.
sync && echo 3 > /proc/sys/vm/drop_caches
When you run
after running the above command you will see the buffers and cached values are either zero or very low. and the Total/Used/Free columns are much clearer.
Please do NOT do this on a live production server unless you know what you are doing.