From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756133AbbAWSAU (ORCPT ); Fri, 23 Jan 2015 13:00:20 -0500 Received: from mail-yk0-f172.google.com ([209.85.160.172]:63282 "EHLO mail-yk0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754530AbbAWSAS (ORCPT ); Fri, 23 Jan 2015 13:00:18 -0500 MIME-Version: 1.0 In-Reply-To: References: <1421928077-4698-1-git-send-email-pang.xunlei@linaro.org> Date: Sat, 24 Jan 2015 02:00:17 +0800 Message-ID: Subject: Re: [PATCH v2 1/3] time: Don't bother to run rtc_resume() for the nonstop clocksource From: Xunlei Pang To: John Stultz Cc: lkml , "rtc-linux@googlegroups.com" , Thomas Gleixner , Alessandro Zummo , Arnd Bergmann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23 January 2015 at 02:30, John Stultz wrote: > On Thu, Jan 22, 2015 at 4:01 AM, Xunlei Pang wrote: >> If a system does not provide a persistent_clock(), the time >> will be updated on resume by rtc_resume(). With the addition >> of the non-stop clocksources for suspend timing, those systems >> set the time on resume in timekeeping_resume(), but may not >> provide a valid persistent_clock(). >> >> This results in the rtc_resume() logic thinking no one has set >> the time and it then will over-write the suspend time again, >> which is not necessary and only increases clock error. >> >> So, fix this for rtc_resume(). >> >> Signed-off-by: Xunlei Pang >> --- >> v1->v2: >> Modify according to Thomas' feedback. >> >> drivers/rtc/class.c | 2 +- >> include/linux/timekeeping.h | 7 +++++++ >> kernel/time/timekeeping.c | 16 +++++----------- >> 3 files changed, 13 insertions(+), 12 deletions(-) >> >> diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c >> index 472a5ad..6100af5 100644 >> --- a/drivers/rtc/class.c >> +++ b/drivers/rtc/class.c >> @@ -102,7 +102,7 @@ static int rtc_resume(struct device *dev) >> struct timespec64 sleep_time; >> int err; >> >> - if (has_persistent_clock()) >> + if (timekeeping_sleeptime_injected()) >> return 0; >> >> rtc_hctosys_ret = -ENODEV; >> diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h >> index 9b63d13..2b87c64 100644 >> --- a/include/linux/timekeeping.h >> +++ b/include/linux/timekeeping.h >> @@ -238,6 +238,13 @@ extern void getnstime_raw_and_real(struct timespec *ts_raw, >> */ >> extern bool persistent_clock_exist; >> extern int persistent_clock_is_local; >> +extern bool timekeeping_sleeptime_inject; >> + >> +/* Used by rtc_resume() */ >> +static inline bool timekeeping_sleeptime_injected(void) >> +{ >> + return timekeeping_sleeptime_inject; >> +} >> > > Again, there's no reason to make this a static inline, nor the > sleeptime_inject variable global. > Just make it a function in timekeeping and provide definition so it > can be used by the rtc resume. Hi John, Thanks for your comments, I've refined it, is this one ok? --- drivers/rtc/class.c | 2 +- include/linux/timekeeping.h | 1 + kernel/time/timekeeping.c | 32 ++++++++++++++++++++------------ 3 files changed, 22 insertions(+), 13 deletions(-) diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 472a5ad..6100af5 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -102,7 +102,7 @@ static int rtc_resume(struct device *dev) struct timespec64 sleep_time; int err; - if (has_persistent_clock()) + if (timekeeping_sleeptime_injected()) return 0; rtc_hctosys_ret = -ENODEV; diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index 9b63d13..17a460d 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -225,6 +225,7 @@ static inline void timekeeping_clocktai(struct timespec *ts) /* * RTC specific */ +extern bool timekeeping_sleeptime_injected(void); extern void timekeeping_inject_sleeptime64(struct timespec64 *delta); /* diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 6a93185..b02133e 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1125,12 +1125,26 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, tk_debug_account_sleep_time(delta); } +static bool sleeptime_inject; + +#if defined(CONFIG_RTC_CLASS) && \ + defined(CONFIG_PM_SLEEP) && \ + defined(CONFIG_RTC_HCTOSYS_DEVICE) +/** + * Used by rtc_resume(). + */ +bool timekeeping_sleeptime_injected(void) +{ + return sleeptime_inject; +} + /** * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values * @delta: pointer to a timespec64 delta value * * This hook is for architectures that cannot support read_persistent_clock - * because their RTC/persistent clock is only accessible when irqs are enabled. + * because their RTC/persistent clock is only accessible when irqs are enabled, + * and also don't have an effective nonstop clocksource. * * This function should only be called by rtc_resume(), and allows * a suspend offset to be injected into the timekeeping values. @@ -1140,13 +1154,6 @@ void timekeeping_inject_sleeptime64(struct timespec64 *delta) struct timekeeper *tk = &tk_core.timekeeper; unsigned long flags; - /* - * Make sure we don't set the clock twice, as timekeeping_resume() - * already did it - */ - if (has_persistent_clock()) - return; - raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); @@ -1162,6 +1169,7 @@ void timekeeping_inject_sleeptime64(struct timespec64 *delta) /* signal hrtimers about time change */ clock_was_set(); } +#endif /** * timekeeping_resume - Resumes the generic timekeeping subsystem. @@ -1178,8 +1186,8 @@ static void timekeeping_resume(void) struct timespec64 ts_new, ts_delta; struct timespec tmp; cycle_t cycle_now, cycle_delta; - bool suspendtime_found = false; + sleeptime_inject = false; read_persistent_clock(&tmp); ts_new = timespec_to_timespec64(tmp); @@ -1226,13 +1234,13 @@ static void timekeeping_resume(void) nsec += ((u64) cycle_delta * mult) >> shift; ts_delta = ns_to_timespec64(nsec); - suspendtime_found = true; + sleeptime_inject = true; } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); - suspendtime_found = true; + sleeptime_inject = true; } - if (suspendtime_found) + if (sleeptime_inject) __timekeeping_inject_sleeptime(tk, &ts_delta); /* Re-base the last cycle value */ -- 1.9.1