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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-09-20 16:59:47 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-10-23 14:46:47 -0700 |
| commit | abfd6e58aed4f89fd69b9b17bc4b4527efe3a645 (patch) | |
| tree | 47c72852a260b3063ef362e4d68e6a8ce7f1f7c3 /kernel/rcutree.c | |
| parent | 6f0c0580b70c89094b3422ba81118c7b959c7556 (diff) | |
| download | linux-abfd6e58aed4f89fd69b9b17bc4b4527efe3a645.tar.gz linux-abfd6e58aed4f89fd69b9b17bc4b4527efe3a645.tar.bz2 linux-abfd6e58aed4f89fd69b9b17bc4b4527efe3a645.zip | |
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>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 74df86bd9204..ac8aed8ee417 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; |