[PATCH 9/9] sched-clock: Migrate to use new tick dependency mask model

[Frederic Weisbecker]

Instead of checking sched_clock_stable from the nohz subsystem to verify
its tick dependency, migrate it to the new mask in order to include it
to the all-in-one check.

Reviewed-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
 kernel/sched/clock.c     |  5 +++++
 kernel/time/tick-sched.c | 19 -------------------
 2 files changed, 5 insertions(+), 19 deletions(-)

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index bc54e84..5b8d349 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -61,6 +61,7 @@
 #include <linux/static_key.h>
 #include <linux/workqueue.h>
 #include <linux/compiler.h>
+#include <linux/tick.h>
 
 /*
  * Scheduler clock - returns current time in nanosec units.
@@ -89,6 +90,8 @@ static void __set_sched_clock_stable(void)
 {
 	if (!sched_clock_stable())
 		static_key_slow_inc(&__sched_clock_stable);
+
+	tick_clear_dep(TICK_CLOCK_UNSTABLE_BIT);
 }
 
 void set_sched_clock_stable(void)
@@ -108,6 +111,8 @@ static void __clear_sched_clock_stable(struct work_struct *work)
 	/* XXX worry about clock continuity */
 	if (sched_clock_stable())
 		static_key_slow_dec(&__sched_clock_stable);
+
+	tick_set_dep(TICK_CLOCK_UNSTABLE_BIT);
 }
 
 static DECLARE_WORK(sched_clock_work, __clear_sched_clock_stable);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 1f5226b..cd5b4cf 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -202,25 +202,6 @@ static bool can_stop_full_tick(struct tick_sched *ts)
 		return false;
 	}
 
-#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-	/*
-	 * sched_clock_tick() needs us?
-	 *
-	 * TODO: kick full dynticks CPUs when
-	 * sched_clock_stable is set.
-	 */
-	if (!sched_clock_stable()) {
-		trace_tick_stop(0, TICK_CLOCK_UNSTABLE_MASK);
-		/*
-		 * Don't allow the user to think they can get
-		 * full NO_HZ with this machine.
-		 */
-		WARN_ONCE(tick_nohz_full_running,
-			  "NO_HZ FULL will not work with unstable sched clock");
-		return false;
-	}
-#endif
-
 	return true;
 }
 
-- 
2.7.0