Grace Period Detection (RCU core)
x	rcu_gp_in_progress(), cpu_needs_another_gp(), rcu_start_gp_per_cpu(),
	rcu_start_gp(),
x	invoke_rcu_core(),
	__rcu_process_gp_end(!),
	rcu_process_gp_end(),
	__note_new_gpnum(), note_new_gpnum(),
	check_for_new_grace_period(),
x	rcu_report_qs_rsp(),
	rcu_report_qs_rnp(),
	rcu_report_qs_rdp(),
x	rcu_check_quiescent_state(),
	__rcu_process_callbacks(),
	rcu_preempt_process_callbacks()
	rcu_process_callbacks(),
x	__rcu_pending(), rcu_preempt_pending(), rcu_pending(),
x	__call_rcu()
x	rcu_preempt_check_blocked_tasks(),
	rcu_report_unblock_qs_rnp(),
	rcu_preempt_blocked_readers_cgp(),

------------------------------------------------------------------------

Quick Quiz:
Why not align rcu_node boundaries with cache/core boundaries?

A: Align with socket boundaries.  Use CONFIG_RCU_FANOUT to make
this happen if needed.  But mostly you won't be able to tell the
difference...

