1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index ca560364d8cd..bf8a6f9f134d 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -81,6 +81,8 @@ struct rcu_dynticks {
 struct rcu_node {
         spinlock_t lock;
         long    gpnum;          /* Current grace period for this node. */
+                                /*  This will either be equal to or one */
+                                /*  behind the root rcu_node's gpnum. */
         unsigned long qsmask;   /* CPUs or groups that need to switch in */
                                 /*  order for current grace period to proceed.*/
         unsigned long qsmaskinit;