linux-kernel - [PATCH] sched: Remove ACCESS

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Date:	Mon, 11 Aug 2014 18:51:41 -0400
From:	Pranith Kumar <bobby.prani@...il.com>
To:	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org (open list:SCHEDULER)
Subject: [PATCH] sched: Remove ACCESS_ONCE() for jiffies

jiffies is declared as a volatile variable. Therefore it is not neccessary to
use ACCESS_ONCE() while reading it.

Signed-off-by: Pranith Kumar <bobby.prani@...il.com>
---
 kernel/sched/core.c | 2 +-
 kernel/sched/proc.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ec1a286..381d0d0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2552,7 +2552,7 @@ void scheduler_tick(void)
 u64 scheduler_tick_max_deferment(void)
 {
 	struct rq *rq = this_rq();
-	unsigned long next, now = ACCESS_ONCE(jiffies);
+	unsigned long next, now = jiffies;
 
 	next = rq->last_sched_tick + HZ;
 
diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c
index 8ecd552..87ab31b 100644
--- a/kernel/sched/proc.c
+++ b/kernel/sched/proc.c
@@ -526,7 +526,7 @@ static inline unsigned long get_rq_runnable_load(struct rq *rq)
  */
 void update_idle_cpu_load(struct rq *this_rq)
 {
-	unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
+	unsigned long curr_jiffies = jiffies;
 	unsigned long load = get_rq_runnable_load(this_rq);
 	unsigned long pending_updates;
 
@@ -548,7 +548,7 @@ void update_idle_cpu_load(struct rq *this_rq)
 void update_cpu_load_nohz(void)
 {
 	struct rq *this_rq = this_rq();
-	unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
+	unsigned long curr_jiffies = jiffies;
 	unsigned long pending_updates;
 
 	if (curr_jiffies == this_rq->last_load_update_tick)
-- 
1.9.1

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