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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-08-07 22:03:45 +0300
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-10-08 02:02:49 +0300
commit807226e2fbb504d82cd504b7b6114896db41ef63 (patch)
treea64112de63cd0c61323be551433dd7ba476de50d /kernel/rcu
parent83c2c735e78da1a0d994911f730f6e1d36c88d7a (diff)
downloadlinux-807226e2fbb504d82cd504b7b6114896db41ef63.tar.xz
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@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c14
1 files changed, 1 insertions, 13 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 15b19baaade5..7e7df5deadf9 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);