From 2c6ee50333f25afb50e88bc20f9dbbb7a6d4578a Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sat, 20 Apr 2013 17:11:50 +0200
Subject: [PATCH] --- yaml --- r: 372926 b: refs/heads/master c:
 99e5ada9407cc19d7c4c05ce2165f20dc46fc093 h: refs/heads/master v: v3

---
 [refs]                         |  2 +-
 trunk/include/linux/tick.h     |  2 ++
 trunk/kernel/sched/core.c      |  2 ++
 trunk/kernel/time/tick-sched.c | 20 ++++++++++++++++++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index de457d6659f3..b66d91c51ae8 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5811d9963e26146898a24b535b301f7654257f8a
+refs/heads/master: 99e5ada9407cc19d7c4c05ce2165f20dc46fc093
diff --git a/trunk/include/linux/tick.h b/trunk/include/linux/tick.h
index e31e67623ea1..9180f4b85e6d 100644
--- a/trunk/include/linux/tick.h
+++ b/trunk/include/linux/tick.h
@@ -163,12 +163,14 @@ extern int tick_nohz_full_cpu(int cpu);
 extern void tick_nohz_full_check(void);
 extern void tick_nohz_full_kick(void);
 extern void tick_nohz_full_kick_all(void);
+extern void tick_nohz_task_switch(struct task_struct *tsk);
 #else
 static inline void tick_nohz_init(void) { }
 static inline int tick_nohz_full_cpu(int cpu) { return 0; }
 static inline void tick_nohz_full_check(void) { }
 static inline void tick_nohz_full_kick(void) { }
 static inline void tick_nohz_full_kick_all(void) { }
+static inline void tick_nohz_task_switch(struct task_struct *tsk) { }
 #endif
 
 
diff --git a/trunk/kernel/sched/core.c b/trunk/kernel/sched/core.c
index 9ad35005f1cb..dd09def88567 100644
--- a/trunk/kernel/sched/core.c
+++ b/trunk/kernel/sched/core.c
@@ -1896,6 +1896,8 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
 		kprobe_flush_task(prev);
 		put_task_struct(prev);
 	}
+
+	tick_nohz_task_switch(current);
 }
 
 #ifdef CONFIG_SMP
diff --git a/trunk/kernel/time/tick-sched.c b/trunk/kernel/time/tick-sched.c
index d0ed1905a85c..12a900dbb819 100644
--- a/trunk/kernel/time/tick-sched.c
+++ b/trunk/kernel/time/tick-sched.c
@@ -232,6 +232,26 @@ void tick_nohz_full_kick_all(void)
 	preempt_enable();
 }
 
+/*
+ * Re-evaluate the need for the tick as we switch the current task.
+ * It might need the tick due to per task/process properties:
+ * perf events, posix cpu timers, ...
+ */
+void tick_nohz_task_switch(struct task_struct *tsk)
+{
+	unsigned long flags;
+
+	if (!tick_nohz_full_cpu(smp_processor_id()))
+		return;
+
+	local_irq_save(flags);
+
+	if (tick_nohz_tick_stopped() && !can_stop_full_tick())
+		tick_nohz_full_kick();
+
+	local_irq_restore(flags);
+}
+
 int tick_nohz_full_cpu(int cpu)
 {
 	if (!have_nohz_full_mask)