rcu: avoid pointless blocked-task warnings

If the RCU callback-processing kthread has nothing to do, it parks in
a wait_event().  If RCU remains idle for more than two minutes, the
kernel complains about this.  This commit changes from wait_event()
to wait_event_interruptible() to prevent the kernel from complaining
just because RCU is idle.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Thomas Weber <weber@corscience.de>
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 034493724749..0c343b9a46d5 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -189,7 +189,8 @@ static int rcu_kthread(void *arg)
         unsigned long flags;
 
         for (;;) {
-                wait_event(rcu_kthread_wq, have_rcu_kthread_work != 0);
+                wait_event_interruptible(rcu_kthread_wq,
+                                         have_rcu_kthread_work != 0);
                 morework = rcu_boost();
                 local_irq_save(flags);
                 work = have_rcu_kthread_work;