Came across this page <https://chrisdown.name/2018/01/02/in-defence-of-swap.html>, which gives an overview of the point of swap space. Some people (including myself) think “we have so much RAM on our systems nowadays, why bother allocating any swap space at all?” But really it’s more than just an overflow area for when you run out of RAM, it is a basis for more efficiently managing that RAM, no matter how much you might have. Actually I found the above linked from this <https://www.freedesktop.org/software/systemd/man/systemd-oomd.service.html> manual page on systemd-oomd. This service (available via an additional package on Debian) tries to take corrective action when the system starts running low on memory, before things get bad enough to wake up the kernel’s dreaded “OOM-killer”.