From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757105Ab2GQWBD (ORCPT ); Tue, 17 Jul 2012 18:01:03 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:37367 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757107Ab2GQV7k (ORCPT ); Tue, 17 Jul 2012 17:59:40 -0400 Subject: Patch "timekeeping: Provide hrtimer update function" has been added to the 3.4-stable tree To: johnstul@us.ibm.com, a.p.zijlstra@chello.nl, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, mingo@kernel.org, prarit@redhat.com, tglx@linutronix.de Cc: , From: Date: Tue, 17 Jul 2012 14:59:24 -0700 In-Reply-To: <1342507196-54327-6-git-send-email-johnstul@us.ibm.com> Message-ID: <134256236465@kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ASCII Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a note to let you know that I've just added the patch titled timekeeping: Provide hrtimer update function to the 3.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: timekeeping-provide-hrtimer-update-function.patch and it can be found in the queue-3.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From johnstul@us.ibm.com Tue Jul 17 14:27:23 2012 From: John Stultz Date: Tue, 17 Jul 2012 02:39:54 -0400 Subject: timekeeping: Provide hrtimer update function To: stable@vger.kernel.org Cc: Thomas Gleixner , John Stultz , Prarit Bhargava , Linux Kernel Message-ID: <1342507196-54327-6-git-send-email-johnstul@us.ibm.com> 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 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 Signed-off-by: John Stultz Signed-off-by: Greg Kroah-Hartman --- include/linux/hrtimer.h | 1 + kernel/time/timekeeping.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+) --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -327,6 +327,7 @@ extern ktime_t ktime_get(void); extern ktime_t ktime_get_real(void); extern ktime_t ktime_get_boottime(void); extern ktime_t ktime_get_monotonic_offset(void); +extern ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot); DECLARE_PER_CPU(struct tick_device, tick_cpu_device); --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1273,6 +1273,40 @@ void get_xtime_and_monotonic_and_sleep_o } while (read_seqretry(&timekeeper.lock, seq)); } +#ifdef CONFIG_HIGH_RES_TIMERS +/** + * ktime_get_update_offsets - hrtimer helper + * @offs_real: pointer to storage for monotonic -> realtime offset + * @offs_boot: pointer to storage for monotonic -> boottime 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 *offs_real, ktime_t *offs_boot) +{ + ktime_t now; + unsigned int seq; + u64 secs, nsecs; + + do { + seq = read_seqbegin(&timekeeper.lock); + + secs = timekeeper.xtime.tv_sec; + nsecs = timekeeper.xtime.tv_nsec; + nsecs += timekeeping_get_ns(); + /* If arch requires, add in gettimeoffset() */ + nsecs += arch_gettimeoffset(); + + *offs_real = timekeeper.offs_real; + *offs_boot = timekeeper.offs_boot; + } while (read_seqretry(&timekeeper.lock, seq)); + + now = ktime_add_ns(ktime_set(secs, 0), nsecs); + now = ktime_sub(now, *offs_real); + return now; +} +#endif + /** * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format */ Patches currently in stable-queue which might be from johnstul@us.ibm.com are queue-3.4/timekeeping-fix-leapsecond-triggered-load-spike-issue.patch queue-3.4/hrtimer-update-hrtimer-base-offsets-each-hrtimer_interrupt.patch queue-3.4/timekeeping-add-missing-update-call-in-timekeeping_resume.patch queue-3.4/hrtimers-move-lock-held-region-in-hrtimer_interrupt.patch queue-3.4/hrtimer-provide-clock_was_set_delayed.patch queue-3.4/timekeeping-provide-hrtimer-update-function.patch queue-3.4/timekeeping-maintain-ktime_t-based-offsets-for-hrtimers.patch