time: Remove xtime_cache
With the earlier logarithmic time accumulation patch, xtime will now always be within one "tick" of the current time, instead of possibly half a second off. This removes the need for the xtime_cache value, which always stored the time at the last interrupt, so this patch cleans that up removing the xtime_cache related code. This patch also addresses an issue with an earlier version of this change, where xtime_cache was normalizing xtime, which could in some cases be not valid (ie: tv_nsec == NSEC_PER_SEC). This is fixed by handling the edge case in update_wall_time(). Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Petr Titěra <P.Titera@century.cz> LKML-Reference: <1270589451-30773-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -150,7 +150,6 @@ extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
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extern int timekeeping_valid_for_hres(void);
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extern u64 timekeeping_max_deferment(void);
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extern void update_wall_time(void);
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extern void update_xtime_cache(u64 nsec);
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extern void timekeeping_leap_insert(int leapsecond);
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struct tms;
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@ -165,13 +165,6 @@ 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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static struct timespec xtime_cache __attribute__ ((aligned (16)));
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void update_xtime_cache(u64 nsec)
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{
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xtime_cache = xtime;
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timespec_add_ns(&xtime_cache, nsec);
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}
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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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@ -332,8 +325,6 @@ int do_settimeofday(struct timespec *tv)
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xtime = *tv;
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update_xtime_cache(0);
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timekeeper.ntp_error = 0;
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ntp_clear();
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@ -559,7 +550,6 @@ void __init timekeeping_init(void)
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}
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set_normalized_timespec(&wall_to_monotonic,
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-boot.tv_sec, -boot.tv_nsec);
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update_xtime_cache(0);
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total_sleep_time.tv_sec = 0;
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total_sleep_time.tv_nsec = 0;
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write_sequnlock_irqrestore(&xtime_lock, flags);
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@ -593,7 +583,6 @@ static int timekeeping_resume(struct sys_device *dev)
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wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
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total_sleep_time = timespec_add_safe(total_sleep_time, ts);
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}
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update_xtime_cache(0);
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/* re-base the last cycle value */
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timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
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timekeeper.ntp_error = 0;
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@ -788,7 +777,6 @@ void update_wall_time(void)
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{
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struct clocksource *clock;
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cycle_t offset;
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u64 nsecs;
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int shift = 0, maxshift;
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/* Make sure we're fully resumed: */
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@ -846,7 +834,9 @@ void update_wall_time(void)
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timekeeper.ntp_error += neg << timekeeper.ntp_error_shift;
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}
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/* store full nanoseconds into xtime after rounding it up and
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/*
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* Store full nanoseconds into xtime after rounding it up and
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* add the remainder to the error difference.
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*/
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xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1;
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@ -854,8 +844,15 @@ void update_wall_time(void)
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timekeeper.ntp_error += timekeeper.xtime_nsec <<
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timekeeper.ntp_error_shift;
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nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
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update_xtime_cache(nsecs);
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/*
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* Finally, make sure that after the rounding
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* xtime.tv_nsec isn't larger then NSEC_PER_SEC
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*/
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if (unlikely(xtime.tv_nsec >= NSEC_PER_SEC)) {
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xtime.tv_nsec -= NSEC_PER_SEC;
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xtime.tv_sec++;
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second_overflow();
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}
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/* check to see if there is a new clocksource to use */
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update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult);
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@ -895,13 +892,13 @@ EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
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unsigned long get_seconds(void)
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{
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return xtime_cache.tv_sec;
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return xtime.tv_sec;
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}
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EXPORT_SYMBOL(get_seconds);
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struct timespec __current_kernel_time(void)
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{
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return xtime_cache;
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return xtime;
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}
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struct timespec current_kernel_time(void)
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@ -912,7 +909,7 @@ struct timespec current_kernel_time(void)
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do {
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seq = read_seqbegin(&xtime_lock);
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now = xtime_cache;
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now = xtime;
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} while (read_seqretry(&xtime_lock, seq));
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return now;
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@ -927,7 +924,7 @@ struct timespec get_monotonic_coarse(void)
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do {
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seq = read_seqbegin(&xtime_lock);
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now = xtime_cache;
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now = xtime;
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mono = wall_to_monotonic;
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} while (read_seqretry(&xtime_lock, seq));
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