Commit abfd6e58 authored Sep 20, 2012 by Paul E. McKenney Committed by Paul E. McKenney Oct 23, 2012

rcu: Fix comment about _rcu_barrier()/orphanage exclusion



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>

parent 6f0c0580

kernel/rcutree.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;

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