[yocto] PSA for anyone using openSUSE 42.2 (or similar)

[Trevor Woerner]

Lately I've been seeing very intermittent, sporadic cases where a build will
fail with something similar to:

	fork: Resource temporarily unavailable

and nothing else wrong. Simply restarting the build causes it to succeed
without incident. I had been seeing this, maybe, twice a week (on a build
machine that builds most of the day as well as overnight with Jenkins jobs).

I decided to investigate and found:

	http://unix.stackexchange.com/questions/253903/creating-threads-fails-with-resource-temporarily-unavailable-with-4-3-kernel

which suggests the issue is a combination of
	- linux >= 4.3
	- systemd >= 228

both of which are true when upgrading openSUSE from 42.1 (linux-4.1.36-41/210)
to 42.2 (linux-4.4.36-8/228).

The fix appears to be to modify the "DefaultTasksMax" systemd parameter
(uncommenting it and setting it to "infinity"). On openSUSE 42.2 this is
found in /etc/systemd/system.conf, then
	
	# systemctl daemon-reexec

or reboot.

I just made this adjustment but given it only happened once or twice a week on
a reasonably busy build machine it might be hard to confirm. I'm also not sure
if setting it to "infinity" is sensible ;-)

I'm guessing other host distros probably also fall into this category.