Messages in this thread Patch in this message | | | Date | Tue, 02 Oct 2012 00:52:17 +0200 | From | Willy Tarreau <> | Subject | [ 020/180] 2.6.32.y: time: Avoid making adjustments if we havent accumulated anything |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: John Stultz <john.stultz@linaro.org>
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> Signed-off-by: Willy Tarreau <w@1wt.eu> --- 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 85d51c4..b451c93 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -807,6 +807,10 @@ 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; /* normally this loop will run just once, however in the -- 1.7.2.1.45.g54fbc
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