| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 03/77] time: Avoid making adjustments if we haven't accumulated anything | Date | Tue, 8 Jan 2013 18:34:42 -0500 |
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From: John Stultz <john.stultz@linaro.org>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
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> 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> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- kernel/time/timekeeping.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 0d59077..bbdad71 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -849,6 +849,10 @@ void update_wall_time(void) #else offset = timekeeper.cycle_interval; #endif + /* Check if there's really nothing to do */ + if (offset < timekeeper.cycle_interval) + return; + timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; /* -- 1.7.12.1
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