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>
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);