mm/migrate: correct failure handling if !hugepage_migration_support()

[firefly-linux-kernel-4.4.55.git] / kernel / sched / clock.c

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index 59371549ddf0786aaf6076324df58b8f71cc65c0..6bd6a6731b21220cae9c9691583c59d9c992ff6f 100644 (file)
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -58,6 +58,8 @@
 #include <linux/percpu.h>
 #include <linux/ktime.h>
 #include <linux/sched.h>
+#include <linux/static_key.h>
+#include <linux/workqueue.h>
 
 /*
  * Scheduler clock - returns current time in nanosec units.
@@ -74,7 +76,37 @@ EXPORT_SYMBOL_GPL(sched_clock);
 __read_mostly int sched_clock_running;
 
 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-__read_mostly int sched_clock_stable;
+static struct static_key __sched_clock_stable = STATIC_KEY_INIT;
+
+int sched_clock_stable(void)
+{
+       if (static_key_false(&__sched_clock_stable))
+               return false;
+       return true;
+}
+
+void set_sched_clock_stable(void)
+{
+       if (!sched_clock_stable())
+               static_key_slow_dec(&__sched_clock_stable);
+}
+
+static void __clear_sched_clock_stable(struct work_struct *work)
+{
+       /* XXX worry about clock continuity */
+       if (sched_clock_stable())
+               static_key_slow_inc(&__sched_clock_stable);
+}
+
+static DECLARE_WORK(sched_clock_work, __clear_sched_clock_stable);
+
+void clear_sched_clock_stable(void)
+{
+       if (keventd_up())
+               schedule_work(&sched_clock_work);
+       else
+               __clear_sched_clock_stable(&sched_clock_work);
+}
 
 struct sched_clock_data {
        u64                     tick_raw;
@@ -234,7 +266,7 @@ u64 sched_clock_cpu(int cpu)
        struct sched_clock_data *scd;
        u64 clock;
 
-       if (sched_clock_stable)
+       if (sched_clock_stable())
                return sched_clock();
 
        if (unlikely(!sched_clock_running))
@@ -257,7 +289,7 @@ void sched_clock_tick(void)
        struct sched_clock_data *scd;
        u64 now, now_gtod;
 
-       if (sched_clock_stable)
+       if (sched_clock_stable())
                return;
 
        if (unlikely(!sched_clock_running))
@@ -308,7 +340,10 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
  */
 u64 cpu_clock(int cpu)
 {
-       return sched_clock_cpu(cpu);
+       if (static_key_false(&__sched_clock_stable))
+               return sched_clock_cpu(cpu);
+
+       return sched_clock();
 }
 
 /*
@@ -320,7 +355,10 @@ u64 cpu_clock(int cpu)
  */
 u64 local_clock(void)
 {
-       return sched_clock_cpu(raw_smp_processor_id());
+       if (static_key_false(&__sched_clock_stable))
+               return sched_clock_cpu(raw_smp_processor_id());
+
+       return sched_clock();
 }
 
 #else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
@@ -340,12 +378,12 @@ u64 sched_clock_cpu(int cpu)
 
 u64 cpu_clock(int cpu)
 {
-       return sched_clock_cpu(cpu);
+       return sched_clock();
 }
 
 u64 local_clock(void)
 {
-       return sched_clock_cpu(0);
+       return sched_clock();
 }
 
 #endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */