diff options
| author | John Stultz <john.stultz@linaro.org> | 2012-09-11 14:56:20 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-02 10:39:48 -0700 |
| commit | 4e64f897ce0d333d574143c0a23b1299d6137b4a (patch) | |
| tree | bf7f59f9f627fb300c32547520d32f1e1b2fcc91 | |
| parent | 7df3d033efb005c6018512933078566cd6f49463 (diff) | |
time: Avoid making adjustments if we haven't accumulated anything
commit bf2ac312195155511a0f79325515cbb61929898a upstream.
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.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1345595449-34965-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/time/timekeeping.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index fd06ae855561..df9447b35026 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1055,6 +1055,10 @@ static void update_wall_time(void) #else offset = (clock->read(clock) - clock->cycle_last) & clock->mask; #endif + /* Check if there's really nothing to do */ + if (offset < timekeeper.cycle_interval) + goto out; + timekeeper.xtime_nsec = (s64)timekeeper.xtime.tv_nsec << timekeeper.shift; |