Linux Detailed Memory Usage Table

I’m trying to identify how I could report on the values in the Detailed Memory Usage graph. For the Linux boxes I would like to create an alert for the value from RAM Used -Sh, Bu, Ca but I believe they are all calculated fields. I can not find any reference to them in the database.

I see it referenced in the rrd but i’m not understanding how it’s being figured or how I would be able to report on it. Any help would be greatly appreciated.