linux-kernel - [PATCH tip/core/rcu 1/6] rcu: Remove redundant code from rcu_cleanup_after

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Message-Id: <1380073816-32381-1-git-send-email-paulmck@linux.vnet.ibm.com>
Date:	Tue, 24 Sep 2013 18:50:11 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...nel.org, laijs@...fujitsu.com, dipankar@...ibm.com,
	akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
	josh@...htriplett.org, niv@...ibm.com, tglx@...utronix.de,
	peterz@...radead.org, rostedt@...dmis.org, dhowells@...hat.com,
	edumazet@...gle.com, darren@...art.com, fweisbec@...il.com,
	sbw@....edu, "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 1/6] rcu: Remove redundant code from rcu_cleanup_after_idle()

From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>

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@....com>
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Tested-by: Tibor Billes <tbilles@....com>
---
 kernel/rcutree_plugin.h | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 130c97b..18d9c91 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();
 }
 
 /*
-- 
1.8.1.5

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