Merge tag 'xfs-4.11-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

[linux.git] / kernel / sched / clock.c

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index 7713b2b53f61e619be15a1bd432ddff47844ad62..ad64efe41722bef0e3a056386f677de8ecd3eda9 100644 (file)
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -83,8 +83,15 @@ void sched_clock_init(void)
 }
 
 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+/*
+ * We must start with !__sched_clock_stable because the unstable -> stable
+ * transition is accurate, while the stable -> unstable transition is not.
+ *
+ * Similarly we start with __sched_clock_stable_early, thereby assuming we
+ * will become stable, such that there's only a single 1 -> 0 transition.
+ */
 static DEFINE_STATIC_KEY_FALSE(__sched_clock_stable);
-static int __sched_clock_stable_early;
+static int __sched_clock_stable_early = 1;
 
 /*
  * We want: ktime_get_ns() + gtod_offset == sched_clock() + raw_offset
@@ -132,24 +139,6 @@ static void __set_sched_clock_stable(void)
        tick_dep_clear(TICK_DEP_BIT_CLOCK_UNSTABLE);
 }
 
-void set_sched_clock_stable(void)
-{
-       __sched_clock_stable_early = 1;
-
-       smp_mb(); /* matches sched_clock_init_late() */
-
-       /*
-        * This really should only be called early (before
-        * sched_clock_init_late()) when guestimating our sched_clock() is
-        * solid.
-        *
-        * After that we test stability and we can negate our guess using
-        * clear_sched_clock_stable, possibly from a watchdog.
-        */
-       if (WARN_ON_ONCE(sched_clock_running == 2))
-               __set_sched_clock_stable();
-}
-
 static void __clear_sched_clock_stable(struct work_struct *work)
 {
        struct sched_clock_data *scd = this_scd();
@@ -199,8 +188,6 @@ void sched_clock_init_late(void)
 
        if (__sched_clock_stable_early)
                __set_sched_clock_stable();
-       else
-               __clear_sched_clock_stable(NULL);
 }
 
 /*