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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-09-29 08:15:52 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-12-04 12:26:50 -0800
commit06f60de19d3141f07d954c9275fe7ccca8e96b42 (patch)
treed0521b8b3c3d665bdba8d5854d4b598faa4b96db /kernel/rcu/tree.c
parent6cf10081220ae21175a867d446b3167bcbcb937b (diff)
downloadlinux-sh-06f60de19d3141f07d954c9275fe7ccca8e96b42.tar.gz
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>
Diffstat (limited to 'kernel/rcu/tree.c')
-rw-r--r--kernel/rcu/tree.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 81aa1cdc6bc9..bd2605c144cc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -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);