Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758581AbYCNUD0 (ORCPT ); Fri, 14 Mar 2008 16:03:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758539AbYCNUBK (ORCPT ); Fri, 14 Mar 2008 16:01:10 -0400 Received: from scrub.xs4all.nl ([194.109.195.176]:48225 "EHLO scrub.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754134AbYCNUBB (ORCPT ); Fri, 14 Mar 2008 16:01:01 -0400 Message-Id: <20080314195737.212526899@linux-m68k.org> References: <20080314184001.695807682@linux-m68k.org> User-Agent: quilt/0.46-1 Date: Fri, 14 Mar 2008 19:40:09 +0100 From: zippel@linux-m68k.org To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, johnstul@us.ibm.com Subject: [PATCH 8/8] handle leap second via timer Content-Disposition: inline; filename=leap_sec Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8429 Lines: 277 Remove the leap second handling from second_overflow(), which doesn't has to check for it every second anymore. With CONFIG_NO_HZ this also makes sure the leap second is handled close to the full second. Additionally this makes it possible to abort a leap second properly by resetting the STA_INS/STA_DEL status bits. Signed-off-by: Roman Zippel --- include/linux/clocksource.h | 2 include/linux/timex.h | 1 kernel/time/ntp.c | 133 +++++++++++++++++++++++++++++--------------- kernel/time/timekeeping.c | 4 - 4 files changed, 95 insertions(+), 45 deletions(-) Index: linux-2.6/include/linux/timex.h =================================================================== --- linux-2.6.orig/include/linux/timex.h 2008-03-13 10:32:07.000000000 +0100 +++ linux-2.6/include/linux/timex.h 2008-03-13 10:33:24.000000000 +0100 @@ -210,6 +210,7 @@ extern long time_esterror; /* estimated extern long time_adjust; /* The amount of adjtime left */ +extern void ntp_init(void); extern void ntp_clear(void); /** Index: linux-2.6/kernel/time/ntp.c =================================================================== --- linux-2.6.orig/kernel/time/ntp.c 2008-03-13 10:32:07.000000000 +0100 +++ linux-2.6/kernel/time/ntp.c 2008-03-13 10:33:24.000000000 +0100 @@ -16,6 +16,7 @@ #include #include #include +#include #include /* @@ -26,6 +27,8 @@ unsigned long tick_nsec; /* ACTHZ peri u64 tick_length; static u64 tick_length_base; +static struct hrtimer leap_timer; + #define MAX_TICKADJ 500 /* microsecs */ #define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \ NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ) @@ -120,64 +123,70 @@ void ntp_clear(void) } /* - * this routine handles the overflow of the microsecond field - * - * The tricky bits of code to handle the accurate clock support - * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. - * They were originally developed for SUN and DEC kernels. - * All the kudos should go to Dave for this stuff. + * Leap second processing. If in leap-insert state at the end of the + * day, the system clock is set back one second; if in leap-delete + * state, the system clock is set ahead one second. */ -void second_overflow(void) +static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer) { - s64 time_adj; + enum hrtimer_restart res = HRTIMER_NORESTART; - /* Bump the maxerror field */ - time_maxerror += MAXFREQ / NSEC_PER_USEC; - if (time_maxerror > NTP_PHASE_LIMIT) { - time_maxerror = NTP_PHASE_LIMIT; - time_status |= STA_UNSYNC; - } + write_seqlock_irq(&xtime_lock); - /* - * Leap second processing. If in leap-insert state at the end of the - * day, the system clock is set back one second; if in leap-delete - * state, the system clock is set ahead one second. The microtime() - * routine or external clock driver will insure that reported time is - * always monotonic. The ugly divides should be replaced. - */ switch (time_state) { case TIME_OK: - if (time_status & STA_INS) - time_state = TIME_INS; - else if (time_status & STA_DEL) - time_state = TIME_DEL; break; case TIME_INS: - if (xtime.tv_sec % 86400 == 0) { - xtime.tv_sec--; - wall_to_monotonic.tv_sec++; - time_state = TIME_OOP; - printk(KERN_NOTICE "Clock: inserting leap second " - "23:59:60 UTC\n"); - } + xtime.tv_sec--; + wall_to_monotonic.tv_sec++; + time_state = TIME_OOP; + printk(KERN_NOTICE "Clock: " + "inserting leap second 23:59:60 UTC\n"); + leap_timer.expires = ktime_add_ns(leap_timer.expires, + NSEC_PER_SEC); + res = HRTIMER_RESTART; break; case TIME_DEL: - if ((xtime.tv_sec + 1) % 86400 == 0) { - xtime.tv_sec++; - time_tai--; - wall_to_monotonic.tv_sec--; - time_state = TIME_WAIT; - printk(KERN_NOTICE "Clock: deleting leap second " - "23:59:59 UTC\n"); - } + xtime.tv_sec++; + time_tai--; + wall_to_monotonic.tv_sec--; + time_state = TIME_WAIT; + printk(KERN_NOTICE "Clock: " + "deleting leap second 23:59:59 UTC\n"); break; case TIME_OOP: time_tai++; time_state = TIME_WAIT; - break; + /* fall through */ case TIME_WAIT: if (!(time_status & (STA_INS | STA_DEL))) time_state = TIME_OK; + break; + } + update_vsyscall(&xtime, clock); + + write_sequnlock_irq(&xtime_lock); + + return res; +} + +/* + * this routine handles the overflow of the microsecond field + * + * The tricky bits of code to handle the accurate clock support + * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. + * They were originally developed for SUN and DEC kernels. + * All the kudos should go to Dave for this stuff. + */ +void second_overflow(void) +{ + s64 time_adj; + + /* Bump the maxerror field */ + time_maxerror += MAXFREQ / NSEC_PER_USEC; + if (time_maxerror > NTP_PHASE_LIMIT) { + time_maxerror = NTP_PHASE_LIMIT; + time_status |= STA_UNSYNC; } /* @@ -268,7 +277,7 @@ static inline void notify_cmos_timer(voi int do_adjtimex(struct timex *txc) { struct timespec ts; - long save_adjust; + long save_adjust, sec; int result; /* In order to modify anything, you gotta be super-user! */ @@ -289,6 +298,10 @@ int do_adjtimex(struct timex *txc) txc->tick > 1100000/USER_HZ) return -EINVAL; + if (time_state != TIME_OK && txc->modes & ADJ_STATUS) + hrtimer_cancel(&leap_timer); + getnstimeofday(&ts); + write_seqlock_irq(&xtime_lock); /* Save for later - semantics of adjtime is to return old value */ @@ -305,6 +318,34 @@ int do_adjtimex(struct timex *txc) /* only set allowed bits */ time_status &= STA_RONLY; time_status |= txc->status & ~STA_RONLY; + + switch (time_state) { + case TIME_OK: + start_timer: + sec = ts.tv_sec; + if (time_status & STA_INS) { + time_state = TIME_INS; + sec += 86400 - sec % 86400; + hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS); + } else if (time_status & STA_DEL) { + time_state = TIME_DEL; + sec += 86400 - (sec + 1) % 86400; + hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS); + } + break; + case TIME_INS: + case TIME_DEL: + time_state = TIME_OK; + goto start_timer; + break; + case TIME_WAIT: + if (!(time_status & (STA_INS | STA_DEL))) + time_state = TIME_OK; + break; + case TIME_OOP: + hrtimer_restart(&leap_timer); + break; + } } if (txc->modes & ADJ_NANO) @@ -384,7 +425,6 @@ int do_adjtimex(struct timex *txc) txc->stbcnt = 0; write_sequnlock_irq(&xtime_lock); - getnstimeofday(&ts); txc->time.tv_sec = ts.tv_sec; txc->time.tv_usec = ts.tv_nsec; if (!(time_status & STA_NANO)) @@ -402,3 +442,10 @@ static int __init ntp_tick_adj_setup(cha } __setup("ntp_tick_adj=", ntp_tick_adj_setup); + +void __init ntp_init(void) +{ + ntp_clear(); + hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS); + leap_timer.function = ntp_leap_second; +} Index: linux-2.6/kernel/time/timekeeping.c =================================================================== --- linux-2.6.orig/kernel/time/timekeeping.c 2008-03-13 10:32:07.000000000 +0100 +++ linux-2.6/kernel/time/timekeeping.c 2008-03-13 10:33:24.000000000 +0100 @@ -53,7 +53,7 @@ void update_xtime_cache(u64 nsec) timespec_add_ns(&xtime_cache, nsec); } -static struct clocksource *clock; /* pointer to current clocksource */ +struct clocksource *clock; #ifdef CONFIG_GENERIC_TIME @@ -241,7 +241,7 @@ void __init timekeeping_init(void) write_seqlock_irqsave(&xtime_lock, flags); - ntp_clear(); + ntp_init(); clock = clocksource_get_next(); clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); Index: linux-2.6/include/linux/clocksource.h =================================================================== --- linux-2.6.orig/include/linux/clocksource.h 2008-03-10 19:50:33.000000000 +0100 +++ linux-2.6/include/linux/clocksource.h 2008-03-13 10:33:24.000000000 +0100 @@ -93,6 +93,8 @@ struct clocksource { #endif }; +extern struct clocksource *clock; /* current clocksource */ + /* * Clock source flags bits:: */ -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/