A couple of times recently I've noticed my laptop running a bit slow and the disk light flickering a lot. It's an i7 with SSD and 12GB RAM, so I'm not really expecting much slowness when just browsing.
This last time, it bugged me, so I had a quick peek in System Monitor (KSysGuard) and it was showing my 2GB swap partition to be 100% utilised, but physical memory only at 4.8GB out of 11.6 (which is where the graph goes to). So I thought I'd try to empty the swap by turning it off & on again (
swapon -a) but swapoff failed due to insufficient RAM.
This confused me, as I should have about 7GB spare, according to KSysGuard, so I thought I'd see what top had to say. Top showed about 150MB free RAM and 2048/2048MB swap in use. No wonder it was running a bit slow!
Why would KSysGuard under-report memory usage so much and how can I make it top telling porkies?