From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755492AbbCGCul (ORCPT ); Fri, 6 Mar 2015 21:50:41 -0500 Received: from mail-pd0-f173.google.com ([209.85.192.173]:33998 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755147AbbCGCue (ORCPT ); Fri, 6 Mar 2015 21:50:34 -0500 From: John Stultz To: lkml Cc: John Stultz , Dave Jones , Linus Torvalds , Thomas Gleixner , Richard Cochran , Prarit Bhargava , Stephen Boyd , Ingo Molnar , Peter Zijlstra , "David S. Miller" , Martin Schwidefsky Subject: [PATCH 10/12] clocksource: Mostly kill clocksource_register() Date: Fri, 6 Mar 2015 18:50:01 -0800 Message-Id: <1425696603-16878-11-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1425696603-16878-1-git-send-email-john.stultz@linaro.org> References: <1425696603-16878-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A long running project has been to cleanup remaining uses of clocksource_register(), replacing it with the simpler clocksource_register_khz/hz(). However, there are a few cases where we need to self-define our mult/shift values, so switch the function to a more obviously internal __clocksource_register(), and consolidate much of the internal logic so we don't have duplication. Cc: Dave Jones Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Cc: Ingo Molnar Cc: Peter Zijlstra Cc: "David S. Miller" Cc: Martin Schwidefsky Signed-off-by: John Stultz --- arch/s390/kernel/time.c | 2 +- arch/sparc/kernel/time_32.c | 2 +- include/linux/clocksource.h | 10 +++++- kernel/time/clocksource.c | 83 +++++++++++++++++++-------------------------- kernel/time/jiffies.c | 4 +-- 5 files changed, 47 insertions(+), 54 deletions(-) diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index 20660dd..6c273cd 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -283,7 +283,7 @@ void __init time_init(void) if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt)) panic("Couldn't request external interrupt 0x1406"); - if (clocksource_register(&clocksource_tod) != 0) + if (__clocksource_register(&clocksource_tod) != 0) panic("Could not register TOD clock source"); /* Enable TOD clock interrupts on the boot cpu. */ diff --git a/arch/sparc/kernel/time_32.c b/arch/sparc/kernel/time_32.c index 2f80d23..a31c0c8 100644 --- a/arch/sparc/kernel/time_32.c +++ b/arch/sparc/kernel/time_32.c @@ -191,7 +191,7 @@ static __init int setup_timer_cs(void) timer_cs.mult = clocksource_hz2mult(sparc_config.clock_rate, timer_cs.shift); - return clocksource_register(&timer_cs); + return __clocksource_register(&timer_cs); } #ifdef CONFIG_SMP diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 63fe52f..c064349 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -179,7 +179,6 @@ static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift) } -extern int clocksource_register(struct clocksource*); extern int clocksource_unregister(struct clocksource*); extern void clocksource_touch_watchdog(void); extern struct clocksource* clocksource_get_next(void); @@ -204,6 +203,15 @@ __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq); extern void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq); +/* + * Dont' call this unless you're a default clocksource + * (AKA: jiffies) and absolutely have to. + */ +static inline int __clocksource_register(struct clocksource *cs) +{ + return __clocksource_register_scale(cs, 1, 0); +} + static inline int clocksource_register_hz(struct clocksource *cs, u32 hz) { return __clocksource_register_scale(cs, 1, hz); diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 51c7b3a..3f24bb3 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -648,38 +648,52 @@ static void clocksource_enqueue(struct clocksource *cs) void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) { u64 sec; + /* - * Calc the maximum number of seconds which we can run before - * wrapping around. For clocksources which have a mask > 32bit - * we need to limit the max sleep time to have a good - * conversion precision. 10 minutes is still a reasonable - * amount. That results in a shift value of 24 for a - * clocksource with mask >= 40bit and f >= 4GHz. That maps to - * ~ 0.06ppm granularity for NTP. + * Default clocksources are *special* and self-define their mult/shift. + * But, you're not special, so you should specify a freq value. */ - sec = cs->mask; - do_div(sec, freq); - do_div(sec, scale); - if (!sec) - sec = 1; - else if (sec > 600 && cs->mask > UINT_MAX) - sec = 600; - - clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, - NSEC_PER_SEC / scale, sec * scale); - + if (freq) { + /* + * Calc the maximum number of seconds which we can run before + * wrapping around. For clocksources which have a mask > 32bit + * we need to limit the max sleep time to have a good + * conversion precision. 10 minutes is still a reasonable + * amount. That results in a shift value of 24 for a + * clocksource with mask >= 40bit and f >= 4GHz. That maps to + * ~ 0.06ppm granularity for NTP. + */ + sec = cs->mask; + do_div(sec, freq); + do_div(sec, scale); + if (!sec) + sec = 1; + else if (sec > 600 && cs->mask > UINT_MAX) + sec = 600; + + clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, + NSEC_PER_SEC / scale, sec * scale); + } /* * Ensure clocksources that have large mults don't overflow * when adjusted. */ cs->maxadj = clocksource_max_adjustment(cs); - while ((cs->mult + cs->maxadj < cs->mult) - || (cs->mult - cs->maxadj > cs->mult)) { + while (freq && ((cs->mult + cs->maxadj < cs->mult) + || (cs->mult - cs->maxadj > cs->mult))) { cs->mult >>= 1; cs->shift--; cs->maxadj = clocksource_max_adjustment(cs); } + /* + * Only warn for *special* clocksources that self-define + * their mult/shift values and don't specify a freq. + */ + WARN_ONCE(cs->mult + cs->maxadj < cs->mult, + "Clocksource %s might overflow on 11%% adjustment\n", + cs->name); + cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift, cs->maxadj, cs->mask, &cs->max_cycles); @@ -713,35 +727,6 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) } EXPORT_SYMBOL_GPL(__clocksource_register_scale); - -/** - * clocksource_register - Used to install new clocksources - * @cs: clocksource to be registered - * - * Returns -EBUSY if registration fails, zero otherwise. - */ -int clocksource_register(struct clocksource *cs) -{ - /* calculate max adjustment for given mult/shift */ - cs->maxadj = clocksource_max_adjustment(cs); - WARN_ONCE(cs->mult + cs->maxadj < cs->mult, - "Clocksource %s might overflow on 11%% adjustment\n", - cs->name); - - /* calculate max idle time permitted for this clocksource */ - cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift, - cs->maxadj, cs->mask, - &cs->max_cycles); - - mutex_lock(&clocksource_mutex); - clocksource_enqueue(cs); - clocksource_enqueue_watchdog(cs); - clocksource_select(); - mutex_unlock(&clocksource_mutex); - return 0; -} -EXPORT_SYMBOL(clocksource_register); - static void __clocksource_change_rating(struct clocksource *cs, int rating) { list_del(&cs->list); diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c index 7e41390..c4bb518 100644 --- a/kernel/time/jiffies.c +++ b/kernel/time/jiffies.c @@ -95,7 +95,7 @@ EXPORT_SYMBOL(jiffies); static int __init init_jiffies_clocksource(void) { - return clocksource_register(&clocksource_jiffies); + return __clocksource_register(&clocksource_jiffies); } core_initcall(init_jiffies_clocksource); @@ -131,6 +131,6 @@ int register_refined_jiffies(long cycles_per_second) refined_jiffies.mult = ((u32)nsec_per_tick) << JIFFIES_SHIFT; - clocksource_register(&refined_jiffies); + __clocksource_register(&refined_jiffies); return 0; } -- 1.9.1