For the 2nd time my system locked up.
This time I managed to get into one of the character sessions, logged in
as root and top showed the kswapd was eating up lots of cpu. Then free
showed all real and swap memory used. That is 4Gb + 4GB.
Obviously with all my problems, I am having something running away with
my memory. Also see
https://bugzilla.redhat.com/show_bug.cgi?id=1726385