Add memory awareness to system load governor

This will unregister for concurrent jobs whenever available system
memory drops below 5% by default. It does not take into account
buffers or cache which could be reclaimed. Users can tune this up
or down as necessary.

This is a very conservative default and will likely need tuning
once observed in production.

Change-Id: Iab6469c0173d9f5635769d4ab0e8034a41355cd4
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
3 files changed