Commit-ID: 807226e2fbb504d82cd504b7b6114896db41ef63
Gitweb: http://git.kernel.org/tip/807226e2fbb504d82cd504b7b6114896db41ef63
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 7 Aug 2015 12:03:45 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed, 7 Oct 2015 16:02:49 -0700
rcu: Stop excluding CPU hotplug in synchronize_sched_expedited()
Now that synchronize_sched_expedited() uses IPIs, a hook in
rcu_sched_qs(), and the ->expmask field in the rcu_node combining
tree, it is no longer necessary to exclude CPU hotplug. Any
races with CPU hotplug will be detected when attempting to send
the IPI. This commit therefore removes the code excluding
CPU hotplug operations.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 15b19ba..7e7df5d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3785,19 +3785,9 @@ void synchronize_sched_expedited(void)
/* Take a snapshot of the sequence number. */
s = rcu_exp_gp_seq_snap(rsp);
- if (!try_get_online_cpus()) {
- /* CPU hotplug operation in flight, fall back to normal GP. */
- wait_rcu_gp(call_rcu_sched);
- atomic_long_inc(&rsp->expedited_normal);
- return;
- }
- WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id()));
-
rnp = exp_funnel_lock(rsp, s);
- if (rnp == NULL) {
- put_online_cpus();
+ if (rnp == NULL)
return; /* Someone else did our work for us. */
- }
rcu_exp_gp_seq_start(rsp);
sync_sched_exp_select_cpus(rsp);
@@ -3805,8 +3795,6 @@ void synchronize_sched_expedited(void)
rcu_exp_gp_seq_end(rsp);
mutex_unlock(&rnp->exp_funnel_mutex);
-
- put_online_cpus();
}
EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
--
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