sched-clock: Migrate to use new tick dependency mask model

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@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

2 files changed, 5 insertions, 19 deletions

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index bc54e84675da..fedb967a9841 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_dep_clear(TICK_DEP_BIT_CLOCK_UNSTABLE);
 }
 
 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_dep_set(TICK_DEP_BIT_CLOCK_UNSTABLE);
 }
 
 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 e4f2916e66a9..969e6704c3c9 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -204,25 +204,6 @@ 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_DEP_MASK_CLOCK_UNSTABLE);
-                /*
-                 * 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;
 }