Scheduler updates and fixes

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2062831
Upstream Status: Linux
Tested: By me with a series of scheduler stress and performance tests

Scheduler updates and fixes from 5.17 and 5.18-rc1. This series
keeps the scheduler up to date and addresses a handful of potential
issues.

Signed-off-by: Phil Auld pauld@redhat.com