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

From: Nicholas Piggin
Date: Sun Aug 20 2017 - 05:25:28 EST


Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
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