Messages in this thread Patch in this message | | | From | John Stultz <> | Subject | [PATCH 2/3] 3.0.y: time: Avoid making adjustments if we haven't accumulated anything | Date | Tue, 11 Sep 2012 20:49:52 -0400 |
| |
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> 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> Cc: Linux Kernel <linux-kernel@vger.kernel.org> Signed-off-by: John Stultz <john.stultz@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 bfa6be73..3bbaf2d0 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -919,6 +919,10 @@ 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; /* -- 1.7.9.5
| |