mirror of https://gitee.com/openkylin/linux.git
timekeeping: Introduce struct timekeeper
Add struct timekeeper to keep the internal values timekeeping.c needs in regard to the currently selected clock source. This moves the timekeeping intervals, xtime_nsec and the ntp error value from struct clocksource to struct timekeeper. The raw_time is removed from the clocksource as well. It gets treated like xtime as a global variable. Eventually xtime raw_time should be moved to struct timekeeper. [ tglx: minor cleanup ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.613209842@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Martin Schwidefsky
Thomas Gleixner
parent
c55c87c892
commit
155ec60226
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@ -280,7 +280,6 @@ void __init time_init(void)
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now = get_clock();
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tod_to_timeval(now - TOD_UNIX_EPOCH, &xtime);
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clocksource_tod.cycle_last = now;
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clocksource_tod.raw_time = xtime;
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tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, &ts);
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set_normalized_timespec(&wall_to_monotonic, -ts.tv_sec, -ts.tv_nsec);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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@ -155,8 +155,6 @@ extern u64 timecounter_cyc2time(struct timecounter *tc,
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* @flags: flags describing special properties
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* @vread: vsyscall based read
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* @resume: resume function for the clocksource, if necessary
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* @cycle_interval: Used internally by timekeeping core, please ignore.
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* @xtime_interval: Used internally by timekeeping core, please ignore.
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*/
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struct clocksource {
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/*
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@ -182,19 +180,12 @@ struct clocksource {
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#define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0)
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#endif
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/* timekeeping specific data, ignore */
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cycle_t cycle_interval;
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u64 xtime_interval;
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u32 raw_interval;
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/*
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* Second part is written at each timer interrupt
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* Keep it in a different cache line to dirty no
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* more than one cache line.
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*/
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cycle_t cycle_last ____cacheline_aligned_in_smp;
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u64 xtime_nsec;
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s64 error;
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struct timespec raw_time;
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#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
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/* Watchdog related data, used by the framework */
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@ -203,8 +194,6 @@ struct clocksource {
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#endif
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};
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extern struct clocksource *clock; /* current clocksource */
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/*
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* Clock source flags bits::
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*/
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@ -270,50 +259,15 @@ static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
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}
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/**
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* cyc2ns - converts clocksource cycles to nanoseconds
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* @cs: Pointer to clocksource
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* @cycles: Cycles
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* clocksource_cyc2ns - converts clocksource cycles to nanoseconds
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*
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* Uses the clocksource and ntp ajdustment to convert cycle_ts to nanoseconds.
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* Converts cycles to nanoseconds, using the given mult and shift.
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*
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* XXX - This could use some mult_lxl_ll() asm optimization
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*/
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static inline s64 cyc2ns(struct clocksource *cs, cycle_t cycles)
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static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift)
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{
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u64 ret = (u64)cycles;
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ret = (ret * cs->mult) >> cs->shift;
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return ret;
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}
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/**
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* clocksource_calculate_interval - Calculates a clocksource interval struct
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*
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* @c: Pointer to clocksource.
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* @length_nsec: Desired interval length in nanoseconds.
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*
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* Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
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* pair and interval request.
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*
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* Unless you're the timekeeping code, you should not be using this!
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*/
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static inline void clocksource_calculate_interval(struct clocksource *c,
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unsigned long length_nsec)
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{
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u64 tmp;
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/* Do the ns -> cycle conversion first, using original mult */
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tmp = length_nsec;
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tmp <<= c->shift;
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tmp += c->mult_orig/2;
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do_div(tmp, c->mult_orig);
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c->cycle_interval = (cycle_t)tmp;
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if (c->cycle_interval == 0)
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c->cycle_interval = 1;
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/* Go back from cycles -> shifted ns, this time use ntp adjused mult */
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c->xtime_interval = (u64)c->cycle_interval * c->mult;
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c->raw_interval = ((u64)c->cycle_interval * c->mult_orig) >> c->shift;
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return ((u64) cycles * mult) >> shift;
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}
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@ -177,7 +177,8 @@ static void clocksource_watchdog(unsigned long data)
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goto out;
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wdnow = watchdog->read(watchdog);
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wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
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wd_nsec = clocksource_cyc2ns((wdnow - watchdog_last) & watchdog->mask,
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watchdog->mult, watchdog->shift);
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watchdog_last = wdnow;
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list_for_each_entry(cs, &watchdog_list, wd_list) {
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@ -196,7 +197,8 @@ static void clocksource_watchdog(unsigned long data)
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}
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/* Check the deviation from the watchdog clocksource. */
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cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask);
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cs_nsec = clocksource_cyc2ns((csnow - cs->wd_last) &
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cs->mask, cs->mult, cs->shift);
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cs->wd_last = csnow;
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if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
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clocksource_unstable(cs, cs_nsec - wd_nsec);
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@ -19,6 +19,65 @@
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#include <linux/time.h>
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#include <linux/tick.h>
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/* Structure holding internal timekeeping values. */
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struct timekeeper {
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/* Current clocksource used for timekeeping. */
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struct clocksource *clock;
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/* Number of clock cycles in one NTP interval. */
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cycle_t cycle_interval;
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/* Number of clock shifted nano seconds in one NTP interval. */
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u64 xtime_interval;
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/* Raw nano seconds accumulated per NTP interval. */
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u32 raw_interval;
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/* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */
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u64 xtime_nsec;
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/* Difference between accumulated time and NTP time in ntp
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* shifted nano seconds. */
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s64 ntp_error;
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};
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struct timekeeper timekeeper;
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/**
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* timekeeper_setup_internals - Set up internals to use clocksource clock.
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*
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* @clock: Pointer to clocksource.
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*
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* Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
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* pair and interval request.
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*
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* Unless you're the timekeeping code, you should not be using this!
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*/
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static void timekeeper_setup_internals(struct clocksource *clock)
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{
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cycle_t interval;
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u64 tmp;
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timekeeper.clock = clock;
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clock->cycle_last = clock->read(clock);
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/* Do the ns -> cycle conversion first, using original mult */
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tmp = NTP_INTERVAL_LENGTH;
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tmp <<= clock->shift;
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tmp += clock->mult_orig/2;
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do_div(tmp, clock->mult_orig);
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if (tmp == 0)
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tmp = 1;
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interval = (cycle_t) tmp;
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timekeeper.cycle_interval = interval;
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/* Go back from cycles -> shifted ns */
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timekeeper.xtime_interval = (u64) interval * clock->mult;
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timekeeper.raw_interval =
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((u64) interval * clock->mult_orig) >> clock->shift;
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timekeeper.xtime_nsec = 0;
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timekeeper.ntp_error = 0;
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}
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/*
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* This read-write spinlock protects us from races in SMP while
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@ -46,6 +105,11 @@ struct timespec xtime __attribute__ ((aligned (16)));
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struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
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static unsigned long total_sleep_time; /* seconds */
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/*
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* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock.
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*/
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struct timespec raw_time;
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/* flag for if timekeeping is suspended */
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int __read_mostly timekeeping_suspended;
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@ -56,42 +120,42 @@ void update_xtime_cache(u64 nsec)
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timespec_add_ns(&xtime_cache, nsec);
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}
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struct clocksource *clock;
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/* must hold xtime_lock */
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void timekeeping_leap_insert(int leapsecond)
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{
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xtime.tv_sec += leapsecond;
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wall_to_monotonic.tv_sec -= leapsecond;
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update_vsyscall(&xtime, clock);
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update_vsyscall(&xtime, timekeeper.clock);
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}
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#ifdef CONFIG_GENERIC_TIME
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/**
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* clocksource_forward_now - update clock to the current time
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* timekeeping_forward_now - update clock to the current time
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*
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* Forward the current clock to update its state since the last call to
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* update_wall_time(). This is useful before significant clock changes,
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* as it avoids having to deal with this time offset explicitly.
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*/
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static void clocksource_forward_now(void)
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static void timekeeping_forward_now(void)
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{
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cycle_t cycle_now, cycle_delta;
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struct clocksource *clock;
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s64 nsec;
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clock = timekeeper.clock;
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cycle_now = clock->read(clock);
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cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
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clock->cycle_last = cycle_now;
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nsec = cyc2ns(clock, cycle_delta);
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nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
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/* If arch requires, add in gettimeoffset() */
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nsec += arch_gettimeoffset();
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timespec_add_ns(&xtime, nsec);
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nsec = ((s64)cycle_delta * clock->mult_orig) >> clock->shift;
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clock->raw_time.tv_nsec += nsec;
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nsec = clocksource_cyc2ns(cycle_delta, clock->mult_orig, clock->shift);
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timespec_add_ns(&raw_time, nsec);
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}
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/**
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@ -103,6 +167,7 @@ static void clocksource_forward_now(void)
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void getnstimeofday(struct timespec *ts)
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{
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cycle_t cycle_now, cycle_delta;
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struct clocksource *clock;
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unsigned long seq;
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s64 nsecs;
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@ -114,13 +179,15 @@ void getnstimeofday(struct timespec *ts)
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*ts = xtime;
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/* read clocksource: */
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clock = timekeeper.clock;
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cycle_now = clock->read(clock);
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/* calculate the delta since the last update_wall_time: */
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cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
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/* convert to nanoseconds: */
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nsecs = cyc2ns(clock, cycle_delta);
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nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
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clock->shift);
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/* If arch requires, add in gettimeoffset() */
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nsecs += arch_gettimeoffset();
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@ -135,6 +202,7 @@ EXPORT_SYMBOL(getnstimeofday);
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ktime_t ktime_get(void)
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{
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cycle_t cycle_now, cycle_delta;
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struct clocksource *clock;
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unsigned int seq;
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s64 secs, nsecs;
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@ -146,13 +214,15 @@ ktime_t ktime_get(void)
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nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec;
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/* read clocksource: */
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clock = timekeeper.clock;
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cycle_now = clock->read(clock);
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/* calculate the delta since the last update_wall_time: */
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cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
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/* convert to nanoseconds: */
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nsecs += cyc2ns(clock, cycle_delta);
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nsecs += clocksource_cyc2ns(cycle_delta, clock->mult,
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clock->shift);
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} while (read_seqretry(&xtime_lock, seq));
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/*
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@ -174,6 +244,7 @@ EXPORT_SYMBOL_GPL(ktime_get);
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void ktime_get_ts(struct timespec *ts)
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{
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cycle_t cycle_now, cycle_delta;
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struct clocksource *clock;
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struct timespec tomono;
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unsigned int seq;
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s64 nsecs;
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@ -186,13 +257,15 @@ void ktime_get_ts(struct timespec *ts)
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tomono = wall_to_monotonic;
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/* read clocksource: */
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clock = timekeeper.clock;
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cycle_now = clock->read(clock);
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/* calculate the delta since the last update_wall_time: */
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cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
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/* convert to nanoseconds: */
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nsecs = cyc2ns(clock, cycle_delta);
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nsecs = clocksource_cyc2ns(cycle_delta, clock->mult,
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clock->shift);
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} while (read_seqretry(&xtime_lock, seq));
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@ -233,7 +306,7 @@ int do_settimeofday(struct timespec *tv)
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write_seqlock_irqsave(&xtime_lock, flags);
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clocksource_forward_now();
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timekeeping_forward_now();
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ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec;
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ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec;
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@ -243,10 +316,10 @@ int do_settimeofday(struct timespec *tv)
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update_xtime_cache(0);
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clock->error = 0;
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timekeeper.ntp_error = 0;
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ntp_clear();
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update_vsyscall(&xtime, clock);
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update_vsyscall(&xtime, timekeeper.clock);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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@ -269,10 +342,10 @@ static void change_clocksource(void)
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new = clocksource_get_next();
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if (!new || clock == new)
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if (!new || timekeeper.clock == new)
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return;
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clocksource_forward_now();
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timekeeping_forward_now();
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if (new->enable && !new->enable(new))
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return;
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@ -284,9 +357,9 @@ static void change_clocksource(void)
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*/
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new->mult_orig = new->mult;
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new->raw_time = clock->raw_time;
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old = clock;
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clock = new;
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old = timekeeper.clock;
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timekeeper_setup_internals(new);
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/*
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* Save mult_orig in mult so that the value can be restored
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* regardless if ->enable() updates the value of mult or not.
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@ -295,22 +368,10 @@ static void change_clocksource(void)
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if (old->disable)
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old->disable(old);
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clock->cycle_last = clock->read(clock);
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clock->error = 0;
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clock->xtime_nsec = 0;
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clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
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tick_clock_notify();
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/*
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* We're holding xtime lock and waking up klogd would deadlock
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* us on enqueue. So no printing!
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printk(KERN_INFO "Time: %s clocksource has been installed.\n",
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clock->name);
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*/
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}
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#else /* GENERIC_TIME */
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static inline void clocksource_forward_now(void) { }
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static inline void timekeeping_forward_now(void) { }
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static inline void change_clocksource(void) { }
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/**
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@ -380,20 +441,23 @@ void getrawmonotonic(struct timespec *ts)
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unsigned long seq;
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s64 nsecs;
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cycle_t cycle_now, cycle_delta;
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struct clocksource *clock;
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do {
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seq = read_seqbegin(&xtime_lock);
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/* read clocksource: */
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clock = timekeeper.clock;
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cycle_now = clock->read(clock);
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/* calculate the delta since the last update_wall_time: */
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cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
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/* convert to nanoseconds: */
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nsecs = ((s64)cycle_delta * clock->mult_orig) >> clock->shift;
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nsecs = clocksource_cyc2ns(cycle_delta, clock->mult_orig,
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clock->shift);
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*ts = clock->raw_time;
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*ts = raw_time;
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} while (read_seqretry(&xtime_lock, seq));
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@ -413,7 +477,7 @@ int timekeeping_valid_for_hres(void)
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do {
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seq = read_seqbegin(&xtime_lock);
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ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
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ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
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} while (read_seqretry(&xtime_lock, seq));
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@ -439,6 +503,7 @@ unsigned long __attribute__((weak)) read_persistent_clock(void)
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*/
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void __init timekeeping_init(void)
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{
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struct clocksource *clock;
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unsigned long flags;
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unsigned long sec = read_persistent_clock();
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@ -451,11 +516,13 @@ void __init timekeeping_init(void)
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clock->enable(clock);
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/* set mult_orig on enable */
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clock->mult_orig = clock->mult;
|
||||
clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
|
||||
clock->cycle_last = clock->read(clock);
|
||||
|
||||
timekeeper_setup_internals(clock);
|
||||
|
||||
xtime.tv_sec = sec;
|
||||
xtime.tv_nsec = 0;
|
||||
raw_time.tv_sec = 0;
|
||||
raw_time.tv_nsec = 0;
|
||||
set_normalized_timespec(&wall_to_monotonic,
|
||||
-xtime.tv_sec, -xtime.tv_nsec);
|
||||
update_xtime_cache(0);
|
||||
|
|
@ -492,8 +559,8 @@ static int timekeeping_resume(struct sys_device *dev)
|
|||
}
|
||||
update_xtime_cache(0);
|
||||
/* re-base the last cycle value */
|
||||
clock->cycle_last = clock->read(clock);
|
||||
clock->error = 0;
|
||||
timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
|
||||
timekeeper.ntp_error = 0;
|
||||
timekeeping_suspended = 0;
|
||||
write_sequnlock_irqrestore(&xtime_lock, flags);
|
||||
|
||||
|
|
@ -514,7 +581,7 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
|
|||
timekeeping_suspend_time = read_persistent_clock();
|
||||
|
||||
write_seqlock_irqsave(&xtime_lock, flags);
|
||||
clocksource_forward_now();
|
||||
timekeeping_forward_now();
|
||||
timekeeping_suspended = 1;
|
||||
write_sequnlock_irqrestore(&xtime_lock, flags);
|
||||
|
||||
|
|
@ -549,7 +616,7 @@ device_initcall(timekeeping_init_device);
|
|||
* If the error is already larger, we look ahead even further
|
||||
* to compensate for late or lost adjustments.
|
||||
*/
|
||||
static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
|
||||
static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval,
|
||||
s64 *offset)
|
||||
{
|
||||
s64 tick_error, i;
|
||||
|
|
@ -565,7 +632,7 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
|
|||
* here. This is tuned so that an error of about 1 msec is adjusted
|
||||
* within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
|
||||
*/
|
||||
error2 = clock->error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
|
||||
error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
|
||||
error2 = abs(error2);
|
||||
for (look_ahead = 0; error2 > 0; look_ahead++)
|
||||
error2 >>= 2;
|
||||
|
|
@ -574,8 +641,9 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
|
|||
* Now calculate the error in (1 << look_ahead) ticks, but first
|
||||
* remove the single look ahead already included in the error.
|
||||
*/
|
||||
tick_error = tick_length >> (NTP_SCALE_SHIFT - clock->shift + 1);
|
||||
tick_error -= clock->xtime_interval >> 1;
|
||||
tick_error = tick_length >>
|
||||
(NTP_SCALE_SHIFT - timekeeper.clock->shift + 1);
|
||||
tick_error -= timekeeper.xtime_interval >> 1;
|
||||
error = ((error - tick_error) >> look_ahead) + tick_error;
|
||||
|
||||
/* Finally calculate the adjustment shift value. */
|
||||
|
|
@ -600,18 +668,19 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
|
|||
* this is optimized for the most common adjustments of -1,0,1,
|
||||
* for other values we can do a bit more work.
|
||||
*/
|
||||
static void clocksource_adjust(s64 offset)
|
||||
static void timekeeping_adjust(s64 offset)
|
||||
{
|
||||
s64 error, interval = clock->cycle_interval;
|
||||
s64 error, interval = timekeeper.cycle_interval;
|
||||
int adj;
|
||||
|
||||
error = clock->error >> (NTP_SCALE_SHIFT - clock->shift - 1);
|
||||
error = timekeeper.ntp_error >>
|
||||
(NTP_SCALE_SHIFT - timekeeper.clock->shift - 1);
|
||||
if (error > interval) {
|
||||
error >>= 2;
|
||||
if (likely(error <= interval))
|
||||
adj = 1;
|
||||
else
|
||||
adj = clocksource_bigadjust(error, &interval, &offset);
|
||||
adj = timekeeping_bigadjust(error, &interval, &offset);
|
||||
} else if (error < -interval) {
|
||||
error >>= 2;
|
||||
if (likely(error >= -interval)) {
|
||||
|
|
@ -619,15 +688,15 @@ static void clocksource_adjust(s64 offset)
|
|||
interval = -interval;
|
||||
offset = -offset;
|
||||
} else
|
||||
adj = clocksource_bigadjust(error, &interval, &offset);
|
||||
adj = timekeeping_bigadjust(error, &interval, &offset);
|
||||
} else
|
||||
return;
|
||||
|
||||
clock->mult += adj;
|
||||
clock->xtime_interval += interval;
|
||||
clock->xtime_nsec -= offset;
|
||||
clock->error -= (interval - offset) <<
|
||||
(NTP_SCALE_SHIFT - clock->shift);
|
||||
timekeeper.clock->mult += adj;
|
||||
timekeeper.xtime_interval += interval;
|
||||
timekeeper.xtime_nsec -= offset;
|
||||
timekeeper.ntp_error -= (interval - offset) <<
|
||||
(NTP_SCALE_SHIFT - timekeeper.clock->shift);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
@ -637,53 +706,59 @@ static void clocksource_adjust(s64 offset)
|
|||
*/
|
||||
void update_wall_time(void)
|
||||
{
|
||||
struct clocksource *clock;
|
||||
cycle_t offset;
|
||||
s64 nsecs;
|
||||
|
||||
/* Make sure we're fully resumed: */
|
||||
if (unlikely(timekeeping_suspended))
|
||||
return;
|
||||
|
||||
clock = timekeeper.clock;
|
||||
#ifdef CONFIG_GENERIC_TIME
|
||||
offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
|
||||
#else
|
||||
offset = clock->cycle_interval;
|
||||
offset = timekeeper.cycle_interval;
|
||||
#endif
|
||||
clock->xtime_nsec = (s64)xtime.tv_nsec << clock->shift;
|
||||
timekeeper.xtime_nsec = (s64)xtime.tv_nsec << clock->shift;
|
||||
|
||||
/* normally this loop will run just once, however in the
|
||||
* case of lost or late ticks, it will accumulate correctly.
|
||||
*/
|
||||
while (offset >= clock->cycle_interval) {
|
||||
/* accumulate one interval */
|
||||
offset -= clock->cycle_interval;
|
||||
clock->cycle_last += clock->cycle_interval;
|
||||
while (offset >= timekeeper.cycle_interval) {
|
||||
u64 nsecps = (u64)NSEC_PER_SEC << clock->shift;
|
||||
|
||||
clock->xtime_nsec += clock->xtime_interval;
|
||||
if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
|
||||
clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
|
||||
/* accumulate one interval */
|
||||
offset -= timekeeper.cycle_interval;
|
||||
clock->cycle_last += timekeeper.cycle_interval;
|
||||
|
||||
timekeeper.xtime_nsec += timekeeper.xtime_interval;
|
||||
if (timekeeper.xtime_nsec >= nsecps) {
|
||||
timekeeper.xtime_nsec -= nsecps;
|
||||
xtime.tv_sec++;
|
||||
second_overflow();
|
||||
}
|
||||
|
||||
clock->raw_time.tv_nsec += clock->raw_interval;
|
||||
if (clock->raw_time.tv_nsec >= NSEC_PER_SEC) {
|
||||
clock->raw_time.tv_nsec -= NSEC_PER_SEC;
|
||||
clock->raw_time.tv_sec++;
|
||||
raw_time.tv_nsec += timekeeper.raw_interval;
|
||||
if (raw_time.tv_nsec >= NSEC_PER_SEC) {
|
||||
raw_time.tv_nsec -= NSEC_PER_SEC;
|
||||
raw_time.tv_sec++;
|
||||
}
|
||||
|
||||
/* accumulate error between NTP and clock interval */
|
||||
clock->error += tick_length;
|
||||
clock->error -= clock->xtime_interval << (NTP_SCALE_SHIFT - clock->shift);
|
||||
timekeeper.ntp_error += tick_length;
|
||||
timekeeper.ntp_error -= timekeeper.xtime_interval <<
|
||||
(NTP_SCALE_SHIFT - clock->shift);
|
||||
}
|
||||
|
||||
/* correct the clock when NTP error is too big */
|
||||
clocksource_adjust(offset);
|
||||
timekeeping_adjust(offset);
|
||||
|
||||
/*
|
||||
* Since in the loop above, we accumulate any amount of time
|
||||
* in xtime_nsec over a second into xtime.tv_sec, its possible for
|
||||
* xtime_nsec to be fairly small after the loop. Further, if we're
|
||||
* slightly speeding the clocksource up in clocksource_adjust(),
|
||||
* slightly speeding the clocksource up in timekeeping_adjust(),
|
||||
* its possible the required corrective factor to xtime_nsec could
|
||||
* cause it to underflow.
|
||||
*
|
||||
|
|
@ -695,24 +770,26 @@ void update_wall_time(void)
|
|||
* We'll correct this error next time through this function, when
|
||||
* xtime_nsec is not as small.
|
||||
*/
|
||||
if (unlikely((s64)clock->xtime_nsec < 0)) {
|
||||
s64 neg = -(s64)clock->xtime_nsec;
|
||||
clock->xtime_nsec = 0;
|
||||
clock->error += neg << (NTP_SCALE_SHIFT - clock->shift);
|
||||
if (unlikely((s64)timekeeper.xtime_nsec < 0)) {
|
||||
s64 neg = -(s64)timekeeper.xtime_nsec;
|
||||
timekeeper.xtime_nsec = 0;
|
||||
timekeeper.ntp_error += neg << (NTP_SCALE_SHIFT - clock->shift);
|
||||
}
|
||||
|
||||
/* store full nanoseconds into xtime after rounding it up and
|
||||
* add the remainder to the error difference.
|
||||
*/
|
||||
xtime.tv_nsec = ((s64)clock->xtime_nsec >> clock->shift) + 1;
|
||||
clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
|
||||
clock->error += clock->xtime_nsec << (NTP_SCALE_SHIFT - clock->shift);
|
||||
xtime.tv_nsec = ((s64)timekeeper.xtime_nsec >> clock->shift) + 1;
|
||||
timekeeper.xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
|
||||
timekeeper.ntp_error += timekeeper.xtime_nsec <<
|
||||
(NTP_SCALE_SHIFT - clock->shift);
|
||||
|
||||
update_xtime_cache(cyc2ns(clock, offset));
|
||||
nsecs = clocksource_cyc2ns(offset, clock->mult, clock->shift);
|
||||
update_xtime_cache(nsecs);
|
||||
|
||||
/* check to see if there is a new clocksource to use */
|
||||
change_clocksource();
|
||||
update_vsyscall(&xtime, clock);
|
||||
update_vsyscall(&xtime, timekeeper.clock);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
|
|||
Loading…
Reference in New Issue