On Wed, 2019-11-06 at 18:25 +0100, Jan Kara wrote: > On Wed 06-11-19 18:03:10, Robert Stupp wrote: > > Oh, and I just realized, that I have two custom settings in my > > /etc/rc.local - guess, I configured that when I installed that > > machine > > years ago. Sorry, that I haven't mentioned that earlier. > > > > echo 0 > /sys/block/nvme0n1/queue/read_ahead_kb > > echo never > > > /sys/kernel/mm/transparent_hugepage/defrag > > > > That setting is probably not quite standard, but I assume there are > > some database server setups out there, that set RA=0 as well. > > Ok, yes, that explains ra_pages == 0. Thanks for the details. Ah! And with these settings, a fresh & clean installation of Ubuntu eoan (5.3.x kernel), hangs during reboot. And if the VM's booted with these settings in /etc/rc.local, the mlockall(MCL_CURRENT) is reproducible as well.
