RCU tests for Maple Tree

[Paul E. McKenney]

Hello, Liam!

Apologies for my being so slow here, but just wanted to double-check my
understanding of this code.

There appear to be two tests that execute from run_check_rcu():

o	rcu_loop().  This appears to have RCU readers scanning the tree
	while an updater is adding a single range.  (Or replacing it,
	as the case might be.)

o	rcu_val().  This appears to have RCU readers repeatedly reading a
	given value while an updater is adding/replacing a single range.
	The test complains if no one sees the new value.

These tests appear to be the only use of threads, though perhaps the
test harness has some way of creating threads that I missed.

Are there other tests that I should be looking for?

							Thanx, Paul