From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757240Ab3AHXvO (ORCPT ); Tue, 8 Jan 2013 18:51:14 -0500 Received: from mail.windriver.com ([147.11.1.11]:63517 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756561Ab3AHXh1 (ORCPT ); Tue, 8 Jan 2013 18:37:27 -0500 From: Paul Gortmaker To: , CC: John Stultz , Prarit Bhargava , Ingo Molnar , Thomas Gleixner , 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 Message-ID: <1357688156-25387-4-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.12.1 In-Reply-To: <1357688156-25387-1-git-send-email-paul.gortmaker@windriver.com> References: <1357688156-25387-1-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: John Stultz ------------------- 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 Cc: Prarit Bhargava Cc: Ingo Molnar Link: http://lkml.kernel.org/r/1345595449-34965-5-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner Cc: Linux Kernel Signed-off-by: John Stultz Signed-off-by: Paul Gortmaker --- 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