Linux Extendend Memory
check_extmem
An extended memory checker for Linux using physical memory and swap togehter in one check.
check_extmem.pl
An extended memory checker for Linux using physical memory and swap togehter in one check. It uses the following formula to calculate the free ram:
free = (physical used + swap used) - (physical free + swap free + buffers + disk cache)
./check_extmem.pl [ -w -c ]
There is also an icinga2 sample config and a template for pnp4nagios included.
You will find more details in my personal blog: https://gehirn-mag.net/monitoring-linux-extended-memory/ (German only).