diff options
| author | John Stultz <john.stultz@linaro.org> | 2012-08-21 20:30:49 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-09-19 15:05:00 +0100 |
| commit | cfb06dcbc0a63430195cfb70b56bd58311414878 (patch) | |
| tree | 5d4d9437193c1c50c1b3685c83891d96a70a3da9 /kernel/time | |
| parent | 8dd006cdafa7c955f6f4c66d25564d90aa29af1d (diff) | |
time: Avoid making adjustments if we haven't accumulated anything
This is a -stable backport of bf2ac312195155511a0f79325515cbb61929898a
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>
Link: http://lkml.kernel.org/r/1345595449-34965-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel/time')
| -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 36440c88fa8..59544dcbed5 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1033,6 +1033,10 @@ 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) + return; + timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; /* |