This process kswapd (kswapd0, actually) suddenly starts using 100% of one of my cores.
Swap space can be freed using the command,
-=-==--=-==-=-
sync ; echo 3 > /proc/sys/vm/drop_cache
-==-=--=-=-==-
Done
Swap space can be freed using the command,
-=-==--=-==-=-
sync ; echo 3 > /proc/sys/vm/drop_cache
-==-=--=-=-==-
Done