From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Fri, 23 Aug 2013 01:16:16 +0000 (-0700)
Subject: rcu: Remove redundant code from rcu_cleanup_after_idle()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7a497c963eceac42677ce1f5d7bb470abedd15f4;p=linux-beck.git

rcu: Remove redundant code from rcu_cleanup_after_idle()

The rcu_try_advance_all_cbs() function returns a bool saying whether or
not there are callbacks ready to invoke, but rcu_cleanup_after_idle()
rechecks this regardless.  This commit therefore uses the value returned
by rcu_try_advance_all_cbs() instead of making rcu_cleanup_after_idle()
do this recheck.

Reported-by: Tibor Billes <tbilles@gmx.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tibor Billes <tbilles@gmx.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 130c97b027f2..18d9c91f25d1 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1768,17 +1768,11 @@ static void rcu_prepare_for_idle(int cpu)
  */
 static void rcu_cleanup_after_idle(int cpu)
 {
-	struct rcu_data *rdp;
-	struct rcu_state *rsp;
 
 	if (rcu_is_nocb_cpu(cpu))
 		return;
-	rcu_try_advance_all_cbs();
-	for_each_rcu_flavor(rsp) {
-		rdp = per_cpu_ptr(rsp->rda, cpu);
-		if (cpu_has_callbacks_ready_to_invoke(rdp))
-			invoke_rcu_core();
-	}
+	if (rcu_try_advance_all_cbs())
+		invoke_rcu_core();
 }
 
 /*