Hi!

At long last a new version of the hrtick rework! The previous version had a
mysterious deadlock which has been resolved. So far (weeks) the 0-day robot has
not found more issues with these patches.

These patches aim to reduce the hrtick overhead to such an extent that it can
be default enabled. Decoupling the preemption behaviour from CONFIG_HZ, leaving
only load-balancing and time keeping dependent on HZ.

Some (limited) performance runs from 0-day have also not found any regressions
from enabling HRTICK, but it has not run the full suite yet (AFAIU).

Patches also at:

  git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/hrtick