Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 1/7] rcu: Fix comment about _rcu_barrier()/orphanage exclusion | Date | Tue, 30 Oct 2012 09:54:30 -0700 |
| |
From: "Paul E. McKenney" <paul.mckenney@linaro.org>
In the old days, _rcu_barrier() acquired ->onofflock to exclude rcu_send_cbs_to_orphanage(), which allowed the latter to avoid memory barriers in callback handling. However, _rcu_barrier() recently started doing get_online_cpus() to lock out CPU-hotplug operations entirely, which means that the comment in rcu_send_cbs_to_orphanage() that talks about ->onofflock is now obsolete. This commit therefore fixes the comment.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcutree.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 74df86b..ac8aed8 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1581,8 +1581,8 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, { /* * Orphan the callbacks. First adjust the counts. This is safe - * because ->onofflock excludes _rcu_barrier()'s adoption of - * the callbacks, thus no memory barrier is required. + * because _rcu_barrier() excludes CPU-hotplug operations, so it + * cannot be running now. Thus no memory barrier is required. */ if (rdp->nxtlist != NULL) { rsp->qlen_lazy += rdp->qlen_lazy; -- 1.7.8
| |