From 41c02e4acb5ee1f2050b54c5429aec0b1ffebaaa Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sat, 20 Apr 2013 15:43:57 +0200
Subject: [PATCH] --- yaml --- r: 372924 b: refs/heads/master c:
 9014c45d9e2dbb935498a5f1d106e220e8624643 h: refs/heads/master v: v3

---
 [refs]                         |  2 +-
 trunk/kernel/time/tick-sched.c | 42 ++++++++++++++++++++++++++++++----
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index a0a1fa2c38c3..22e367681fa4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ff442c51f6543378cf23107c75b7949dc64a9119
+refs/heads/master: 9014c45d9e2dbb935498a5f1d106e220e8624643
diff --git a/trunk/kernel/time/tick-sched.c b/trunk/kernel/time/tick-sched.c
index 4d74a68b2c34..95d79aeb3e27 100644
--- a/trunk/kernel/time/tick-sched.c
+++ b/trunk/kernel/time/tick-sched.c
@@ -21,6 +21,8 @@
 #include <linux/sched.h>
 #include <linux/module.h>
 #include <linux/irq_work.h>
+#include <linux/posix-timers.h>
+#include <linux/perf_event.h>
 
 #include <asm/irq_regs.h>
 
@@ -147,16 +149,48 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
 static cpumask_var_t nohz_full_mask;
 bool have_nohz_full_mask;
 
+static bool can_stop_full_tick(void)
+{
+	WARN_ON_ONCE(!irqs_disabled());
+
+	if (!sched_can_stop_tick())
+		return false;
+
+	if (!posix_cpu_timers_can_stop_tick(current))
+		return false;
+
+	if (!perf_event_can_stop_tick())
+		return false;
+
+	/* sched_clock_tick() needs us? */
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+	/*
+	 * TODO: kick full dynticks CPUs when
+	 * sched_clock_stable is set.
+	 */
+	if (!sched_clock_stable)
+		return false;
+#endif
+
+	return true;
+}
+
+static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now);
+
 /*
  * Re-evaluate the need for the tick on the current CPU
  * and restart it if necessary.
  */
 void tick_nohz_full_check(void)
 {
-	/*
-	 * STUB for now, will be filled with the full tick stop/restart
-	 * infrastructure patches
-	 */
+	struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
+
+	if (tick_nohz_full_cpu(smp_processor_id())) {
+		if (ts->tick_stopped && !is_idle_task(current)) {
+			if (!can_stop_full_tick())
+				tick_nohz_restart_sched_tick(ts, ktime_get());
+		}
+	}
 }
 
 static void nohz_full_kick_work_func(struct irq_work *work)