I run typically 7 to 10 active tabs during the day.
I can see that starting from a low value, my swap space usage increases bit by bit all day, until eventually when it has got to about 1GB (out of a max 6GB), maybe over a day or two, system problems. Firefox is the only user application running.
There had been a similar issue on Ubuntu 18.04 LTS, using the same configuration and daily tabs, but this seemed to be solved, so that swap usage was stable and low.
vm.swappiness is set to 10.
What has happened here?