Merge branch 'lkmm' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/core

Pull v5.9 LKMM changes from Paul E. McKenney.

Mostly documentation changes, but also some new litmus tests for atomic ops.
Signed-off-by: Ingo Molnar <mingo@kernel.org>