linux-kernel - [PATCH 2/2] sched/idle: Use spin loop primitives for polling idle

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Date:   Sun, 20 Aug 2017 19:25:02 +1000
From:   Nicholas Piggin <npiggin@...il.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>
Cc:     Nicholas Piggin <npiggin@...il.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] sched/idle: Use spin loop primitives for polling idle

Signed-off-by: Nicholas Piggin <npiggin@...il.com>
---
 kernel/sched/idle.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 6c23e30c0e5c..b884980da8ef 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -11,6 +11,7 @@
 #include <linux/stackprotector.h>
 #include <linux/suspend.h>
 #include <linux/livepatch.h>
+#include <linux/processor.h>
 
 #include <asm/tlb.h>
 
@@ -64,9 +65,13 @@ static noinline int __cpuidle cpu_idle_poll(void)
 	trace_cpu_idle_rcuidle(0, smp_processor_id());
 	local_irq_enable();
 	stop_critical_timings();
+
+	spin_begin();
 	while (!tif_need_resched() &&
 		(cpu_idle_force_poll || tick_check_broadcast_expired()))
-		cpu_relax();
+		spin_cpu_relax();
+	spin_end();
+
 	start_critical_timings();
 	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 	rcu_idle_exit();
-- 
2.13.3