From 99e5ada9407cc19d7c4c05ce2165f20dc46fc093 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sat, 20 Apr 2013 17:11:50 +0200
Subject: nohz: Re-evaluate the tick for the new task after a context switch

When a task is scheduled in, it may have some properties
of its own that could make the CPU reconsider the need for
the tick: posix cpu timers, perf events, ...

So notify the full dynticks subsystem when a task gets
scheduled in and re-check the tick dependency at this
stage. This is done through a self IPI to avoid messing
up with any current lock scenario.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/tick.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'include/linux')

diff --git a/include/linux/tick.h b/include/linux/tick.h
index e31e67623ea1..9180f4b85e6d 100644
--- a/include/linux/tick.h
+++ b/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
 
 
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