From patchwork Tue Jul 17 21:49:29 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: john stultz X-Patchwork-Id: 10088 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id F1F9723E3D for ; Tue, 17 Jul 2012 21:50:50 +0000 (UTC) Received: from mail-yw0-f52.google.com (mail-yw0-f52.google.com [209.85.213.52]) by fiordland.canonical.com (Postfix) with ESMTP id C1413A186EE for ; Tue, 17 Jul 2012 21:50:50 +0000 (UTC) Received: by mail-yw0-f52.google.com with SMTP id p61so1041047yhp.11 for ; Tue, 17 Jul 2012 14:50:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-forwarded-to:x-forwarded-for:delivered-to:received-spf:from:to:cc :subject:date:message-id:x-mailer:in-reply-to:references :x-content-scanned:x-cbid:x-gm-message-state; bh=3b4nvQ9NeToXrNNtAkjI3iuzc+OcDpR9/BIl68zvxkU=; b=nU6XL+Pba6Z3PDTSZqz3RtZFsb58R4vp0ZAotxOyhCY6kvMnGZs9u9+xHLOa3xP8g4 q4JAfqv+wn8YgGmHcT7yaweYmAYJ4h4j1UphGwhPzs0OWGZ6VXIED6g1c88oq0E7SyMg 1oCLtW7vA2Ev/NsUfNOXf+puGYiBtHe05FT85QI6sMtuGrxVTA17XdeKPOp3pLhiwXQI nUT+E1TbCe1Mcla/98tlLLPGK+OamwKu9Z/C5umaqZwmFCeN0Z40co/xyLf0poPe9To7 kLFUD4h1DggFjcWFDx3zirE2AYCwsur5LlvlClcUJpdUViuCk725Q7cp0kn1n15v5a2u ij4A== Received: by 10.50.46.232 with SMTP id y8mr162216igm.57.1342561850324; Tue, 17 Jul 2012 14:50:50 -0700 (PDT) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.231.241.2 with SMTP id lc2csp24889ibb; Tue, 17 Jul 2012 14:50:49 -0700 (PDT) Received: by 10.50.10.137 with SMTP id i9mr154778igb.60.1342561849895; Tue, 17 Jul 2012 14:50:49 -0700 (PDT) Received: from e7.ny.us.ibm.com (e7.ny.us.ibm.com. [32.97.182.137]) by mx.google.com with ESMTPS id zs10si18211499igb.27.2012.07.17.14.50.49 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 17 Jul 2012 14:50:49 -0700 (PDT) Received-SPF: pass (google.com: domain of johnstul@us.ibm.com designates 32.97.182.137 as permitted sender) client-ip=32.97.182.137; Authentication-Results: mx.google.com; spf=pass (google.com: domain of johnstul@us.ibm.com designates 32.97.182.137 as permitted sender) smtp.mail=johnstul@us.ibm.com Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 17 Jul 2012 17:50:49 -0400 Received: from d01dlp01.pok.ibm.com (9.56.224.56) by e7.ny.us.ibm.com (192.168.1.107) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 17 Jul 2012 17:49:46 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 9482538C805C for ; Tue, 17 Jul 2012 17:49:45 -0400 (EDT) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q6HLnjka393570 for ; Tue, 17 Jul 2012 17:49:45 -0400 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q6HLniPG026878 for ; Tue, 17 Jul 2012 15:49:44 -0600 Received: from kernel.stglabs.ibm.com (kernel.stglabs.ibm.com [9.114.214.19]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q6HLnZI7026401; Tue, 17 Jul 2012 15:49:43 -0600 From: John Stultz To: stable@vger.kernel.org Cc: Thomas Gleixner , John Stultz , Prarit Bhargava , Linux Kernel Subject: [PATCH 09/11] 2.6.34.x: timekeeping: Provide hrtimer update function Date: Tue, 17 Jul 2012 17:49:29 -0400 Message-Id: <1342561771-55678-10-git-send-email-johnstul@us.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1342561771-55678-1-git-send-email-johnstul@us.ibm.com> References: <1342561771-55678-1-git-send-email-johnstul@us.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12071721-5806-0000-0000-00001765EDF2 X-Gm-Message-State: ALoCoQm8tXc7SxdCk2fGMGupGS7yJHCR4dnNaJJM2DsxcEAlpwd+0OGJAOA3Wqwd8V5ZO0QXw7Zx From: Thomas Gleixner This is a backport of f6c06abfb3972ad4914cef57d8348fcb2932bc3b To finally fix the infamous leap second issue and other race windows caused by functions which change the offsets between the various time bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a function which atomically gets the current monotonic time and updates the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic overhead. The previous patch which provides ktime_t offsets allows us to make this function almost as cheap as ktime_get() which is going to be replaced in hrtimer_interrupt(). Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Prarit Bhargava Cc: stable@vger.kernel.org Signed-off-by: John Stultz Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner Cc: Prarit Bhargava Cc: Thomas Gleixner Cc: Linux Kernel Signed-off-by: John Stultz --- include/linux/hrtimer.h | 2 +- kernel/time/timekeeping.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 0325598..887d1e7 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -319,7 +319,7 @@ static inline void clock_was_set_delayed(void) { } extern ktime_t ktime_get(void); extern ktime_t ktime_get_real(void); - +extern ktime_t ktime_get_update_offsets(ktime_t *offs_real); DECLARE_PER_CPU(struct tick_device, tick_cpu_device); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 3d443b4..0b4f6d1 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -969,3 +969,35 @@ struct timespec get_monotonic_coarse(void) now.tv_nsec + mono.tv_nsec); return now; } + +#ifdef CONFIG_HIGH_RES_TIMERS +/** + * ktime_get_update_offsets - hrtimer helper + * @real: pointer to storage for monotonic -> realtime offset + * + * Returns current monotonic time and updates the offsets + * Called from hrtimer_interupt() or retrigger_next_event() + */ +ktime_t ktime_get_update_offsets(ktime_t *real) +{ + ktime_t now; + unsigned int seq; + u64 secs, nsecs; + + do { + seq = read_seqbegin(&xtime_lock); + + secs = xtime.tv_sec; + nsecs = xtime.tv_nsec; + nsecs += timekeeping_get_ns(); + /* If arch requires, add in gettimeoffset() */ + nsecs += arch_gettimeoffset(); + + *real = offs_real; + } while (read_seqretry(&xtime_lock, seq)); + + now = ktime_add_ns(ktime_set(secs, 0), nsecs); + now = ktime_sub(now, *real); + return now; +} +#endif