I hear you. Webmincron does run long enough to look at it (up to 2-3 hours)… however I have no clue when it actually runs, and if it will run for 5min or an hour. It only seems to be using wild amounts of memory when it runs for an hour+. Up until now, I have been debugging why my VPS sometimes crashes because of out of memory through continuous logging with atop, and checking around times were the VPS stopped, and I’ve landed on webmincron being the issue.
About virtual memory vs residual, I’ve been speaking in residual memory. As mentioned, webmincron peaks at 800MB ram + 2-3GB swap, which crashes the system.
I hope that makes it clear why it’s a problem 
! So my goal is to find out what it’s doing at those times, then make it behave