From: Paul E. McKenney <paul.mckenney@linaro.org>
Date: Wed, 12 Jan 2011 22:18:11 +0000 (-0800)
Subject: rcu: avoid pointless blocked-task warnings
X-Git-Tag: v2.6.38-rc1~37^2^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b24efdfdf679cf9b05947c531971905fc727dd40;p=platform%2Fupstream%2Fkernel-adaptation-pc.git

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>
---

diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 0344937..0c343b9 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;