From 719254faa17ffedc87ba0fadb9b34e535c9758d5 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 17 Oct 2008 09:59:47 +0200
Subject: [PATCH] NOHZ: unify the nohz function calls in irq_enter()

We have two separate nohz function calls in irq_enter() for no good
reason. Just call a single NOHZ function from irq_enter() and call
the bits in the tick code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/tick.h     |  7 +++----
 kernel/softirq.c         | 10 +++-------
 kernel/time/tick-sched.c | 13 ++++++++++++-
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/linux/tick.h b/include/linux/tick.h
index 98921a3e1aa..b6ec8189ac0 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -96,9 +96,11 @@ extern cpumask_t *tick_get_broadcast_oneshot_mask(void);
 extern void tick_clock_notify(void);
 extern int tick_check_oneshot_change(int allow_nohz);
 extern struct tick_sched *tick_get_tick_sched(int cpu);
+extern void tick_check_idle(int cpu);
 # else
 static inline void tick_clock_notify(void) { }
 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
+static inline void tick_check_idle(int cpu) { }
 # endif
 
 #else /* CONFIG_GENERIC_CLOCKEVENTS */
@@ -106,26 +108,23 @@ static inline void tick_init(void) { }
 static inline void tick_cancel_sched_timer(int cpu) { }
 static inline void tick_clock_notify(void) { }
 static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
+static inline void tick_check_idle(int cpu) { }
 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 
 # ifdef CONFIG_NO_HZ
 extern void tick_nohz_stop_sched_tick(int inidle);
 extern void tick_nohz_restart_sched_tick(void);
-extern void tick_nohz_update_jiffies(void);
 extern ktime_t tick_nohz_get_sleep_length(void);
-extern void tick_nohz_stop_idle(int cpu);
 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 # else
 static inline void tick_nohz_stop_sched_tick(int inidle) { }
 static inline void tick_nohz_restart_sched_tick(void) { }
-static inline void tick_nohz_update_jiffies(void) { }
 static inline ktime_t tick_nohz_get_sleep_length(void)
 {
 	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
 
 	return len;
 }
-static inline void tick_nohz_stop_idle(int cpu) { }
 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 # endif /* !NO_HZ */
 
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 37d67aa2d56..d410014279e 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -265,16 +265,12 @@ asmlinkage void do_softirq(void)
  */
 void irq_enter(void)
 {
-#ifdef CONFIG_NO_HZ
 	int cpu = smp_processor_id();
+
 	if (idle_cpu(cpu) && !in_interrupt())
-		tick_nohz_stop_idle(cpu);
-#endif
+		tick_check_idle(cpu);
+
 	__irq_enter();
-#ifdef CONFIG_NO_HZ
-	if (idle_cpu(cpu))
-		tick_nohz_update_jiffies();
-#endif
 }
 
 #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b711ffcb106..fdcf3f93bb8 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -155,7 +155,7 @@ void tick_nohz_update_jiffies(void)
 	touch_softlockup_watchdog();
 }
 
-void tick_nohz_stop_idle(int cpu)
+static void tick_nohz_stop_idle(int cpu)
 {
 	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
 
@@ -558,6 +558,17 @@ static inline void tick_nohz_switch_to_nohz(void) { }
 
 #endif /* NO_HZ */
 
+/*
+ * Called from irq_enter to notify about the possible interruption of idle()
+ */
+void tick_check_idle(int cpu)
+{
+#ifdef CONFIG_NO_HZ
+	tick_nohz_stop_idle(cpu);
+	tick_nohz_update_jiffies();
+#endif
+}
+
 /*
  * High resolution timer specific code
  */
-- 
2.41.1