Commit 06f60de1 authored Sep 29, 2015 by Paul E. McKenney

rcu: Short-circuit synchronize_sched_expedited() if only one CPU

If there is only one CPU, then invoking synchronize_sched_expedited()
is by definition a grace period. This commit checks for this condition
and does a short-circuit return in that case.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

parent 6cf10081

kernel/rcu/tree.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -3822,6 +3822,10 @@ void synchronize_sched_expedited(void)
		struct rcu_node *rnp;
		struct rcu_state *rsp = &rcu_sched_state;

		/* If only one CPU, this is automatically a grace period. */
		if (rcu_blocking_is_gp())
		return;

		/* Take a snapshot of the sequence number. */
		s = rcu_exp_gp_seq_snap(rsp);