If update_wall_time() is called and the current offset isn't
large enough to accumulate, avoid re-calling timekeeping_adjust
which may change the clock freq and can cause 1ns inconsistencies
with CLOCK_REALTIME_COARSE/CLOCK_MONOTONIC_COARSE.
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Prarit Bhargava <pra...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: sta...@vger.kernel.org
Signed-off-by: John Stultz <john.stu...@linaro.org>
---
kernel/time/timekeeping.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index a5a9389..0c1485e 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1152,6 +1152,10 @@ static void update_wall_time(void)
offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
#endif
+ /* Check if there's really nothing to do */
+ if (offset < tk->cycle_interval)
+ goto out;
+
/*
* With NO_HZ we may have to accumulate many cycle_intervals
* (think "ticks") worth of time at once. To do this efficiently,
--
1.7.9.5
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