time: Add timekeeper lock
Now that all the timekeeping variables are stored in the timekeeper structure, add a new lock to protect the structure. For now, this lock nests under the xtime_lock for writes. For readers, we don't need to take xtime_lock anymore. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz
parent
8fcce546be
commit
70471f2f06
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@ -69,6 +69,9 @@ struct timekeeper {
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struct timespec total_sleep_time;
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/* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */
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struct timespec raw_time;
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/* Seqlock for all timekeeper values */
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seqlock_t lock;
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};
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static struct timekeeper timekeeper;
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@ -172,10 +175,17 @@ static inline s64 timekeeping_get_ns_raw(void)
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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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unsigned long flags;
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write_seqlock_irqsave(&timekeeper.lock, flags);
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timekeeper.xtime.tv_sec += leapsecond;
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timekeeper.wall_to_monotonic.tv_sec -= leapsecond;
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update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
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timekeeper.clock, timekeeper.mult);
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write_sequnlock_irqrestore(&timekeeper.lock, flags);
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}
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/**
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@ -222,7 +232,7 @@ void getnstimeofday(struct timespec *ts)
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WARN_ON(timekeeping_suspended);
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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*ts = timekeeper.xtime;
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nsecs = timekeeping_get_ns();
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@ -230,7 +240,7 @@ void getnstimeofday(struct timespec *ts)
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/* If arch requires, add in gettimeoffset() */
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nsecs += arch_gettimeoffset();
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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timespec_add_ns(ts, nsecs);
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}
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@ -245,7 +255,7 @@ ktime_t ktime_get(void)
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WARN_ON(timekeeping_suspended);
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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secs = timekeeper.xtime.tv_sec +
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timekeeper.wall_to_monotonic.tv_sec;
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nsecs = timekeeper.xtime.tv_nsec +
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@ -254,7 +264,7 @@ ktime_t ktime_get(void)
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/* If arch requires, add in gettimeoffset() */
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nsecs += arch_gettimeoffset();
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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/*
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* Use ktime_set/ktime_add_ns to create a proper ktime on
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* 32-bit architectures without CONFIG_KTIME_SCALAR.
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@ -280,14 +290,14 @@ void ktime_get_ts(struct timespec *ts)
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WARN_ON(timekeeping_suspended);
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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*ts = timekeeper.xtime;
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tomono = timekeeper.wall_to_monotonic;
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nsecs = timekeeping_get_ns();
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/* If arch requires, add in gettimeoffset() */
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nsecs += arch_gettimeoffset();
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
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ts->tv_nsec + tomono.tv_nsec + nsecs);
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@ -315,7 +325,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
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do {
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u32 arch_offset;
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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*ts_raw = timekeeper.raw_time;
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*ts_real = timekeeper.xtime;
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@ -328,7 +338,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
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nsecs_raw += arch_offset;
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nsecs_real += arch_offset;
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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timespec_add_ns(ts_raw, nsecs_raw);
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timespec_add_ns(ts_real, nsecs_real);
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@ -362,12 +372,13 @@ EXPORT_SYMBOL(do_gettimeofday);
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int do_settimeofday(const struct timespec *tv)
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{
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struct timespec ts_delta;
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unsigned long flags;
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unsigned long flags1,flags2;
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if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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write_seqlock_irqsave(&xtime_lock, flags);
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write_seqlock_irqsave(&xtime_lock, flags1);
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write_seqlock_irqsave(&timekeeper.lock, flags2);
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timekeeping_forward_now();
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@ -384,7 +395,8 @@ int do_settimeofday(const struct timespec *tv)
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update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
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timekeeper.clock, timekeeper.mult);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_sequnlock_irqrestore(&timekeeper.lock, flags2);
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write_sequnlock_irqrestore(&xtime_lock, flags1);
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/* signal hrtimers about time change */
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clock_was_set();
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@ -403,12 +415,13 @@ EXPORT_SYMBOL(do_settimeofday);
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*/
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int timekeeping_inject_offset(struct timespec *ts)
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{
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unsigned long flags;
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unsigned long flags1,flags2;
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if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
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return -EINVAL;
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write_seqlock_irqsave(&xtime_lock, flags);
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write_seqlock_irqsave(&xtime_lock, flags1);
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write_seqlock_irqsave(&timekeeper.lock, flags2);
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timekeeping_forward_now();
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@ -422,7 +435,8 @@ int timekeeping_inject_offset(struct timespec *ts)
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update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
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timekeeper.clock, timekeeper.mult);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_sequnlock_irqrestore(&timekeeper.lock, flags2);
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write_sequnlock_irqrestore(&xtime_lock, flags1);
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/* signal hrtimers about time change */
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clock_was_set();
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@ -494,11 +508,11 @@ void getrawmonotonic(struct timespec *ts)
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s64 nsecs;
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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nsecs = timekeeping_get_ns_raw();
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*ts = timekeeper.raw_time;
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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timespec_add_ns(ts, nsecs);
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}
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@ -514,24 +528,30 @@ int timekeeping_valid_for_hres(void)
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int ret;
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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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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} while (read_seqretry(&timekeeper.lock, seq));
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return ret;
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}
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/**
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* timekeeping_max_deferment - Returns max time the clocksource can be deferred
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*
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* Caller must observe xtime_lock via read_seqbegin/read_seqretry to
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* ensure that the clocksource does not change!
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*/
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u64 timekeeping_max_deferment(void)
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{
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return timekeeper.clock->max_idle_ns;
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unsigned long seq;
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u64 ret;
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do {
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seq = read_seqbegin(&timekeeper.lock);
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ret = timekeeper.clock->max_idle_ns;
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} while (read_seqretry(&timekeeper.lock, seq));
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return ret;
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}
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/**
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@ -576,10 +596,13 @@ void __init timekeeping_init(void)
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read_persistent_clock(&now);
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read_boot_clock(&boot);
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seqlock_init(&timekeeper.lock);
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write_seqlock_irqsave(&xtime_lock, flags);
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ntp_init();
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_seqlock_irqsave(&timekeeper.lock, flags);
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clock = clocksource_default_clock();
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if (clock->enable)
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clock->enable(clock);
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@ -597,7 +620,7 @@ void __init timekeeping_init(void)
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-boot.tv_sec, -boot.tv_nsec);
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timekeeper.total_sleep_time.tv_sec = 0;
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timekeeper.total_sleep_time.tv_nsec = 0;
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_sequnlock_irqrestore(&timekeeper.lock, flags);
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}
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/* time in seconds when suspend began */
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@ -638,7 +661,7 @@ static void __timekeeping_inject_sleeptime(struct timespec *delta)
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*/
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void timekeeping_inject_sleeptime(struct timespec *delta)
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{
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unsigned long flags;
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unsigned long flags1,flags2;
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struct timespec ts;
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/* Make sure we don't set the clock twice */
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@ -646,7 +669,9 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
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if (!(ts.tv_sec == 0 && ts.tv_nsec == 0))
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return;
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write_seqlock_irqsave(&xtime_lock, flags);
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write_seqlock_irqsave(&xtime_lock, flags1);
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write_seqlock_irqsave(&timekeeper.lock, flags2);
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timekeeping_forward_now();
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__timekeeping_inject_sleeptime(delta);
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@ -656,7 +681,8 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
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update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
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timekeeper.clock, timekeeper.mult);
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_sequnlock_irqrestore(&timekeeper.lock, flags2);
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write_sequnlock_irqrestore(&xtime_lock, flags1);
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/* signal hrtimers about time change */
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clock_was_set();
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@ -672,14 +698,15 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
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*/
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static void timekeeping_resume(void)
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{
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unsigned long flags;
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unsigned long flags1,flags2;
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struct timespec ts;
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read_persistent_clock(&ts);
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clocksource_resume();
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write_seqlock_irqsave(&xtime_lock, flags);
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write_seqlock_irqsave(&xtime_lock, flags1);
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write_seqlock_irqsave(&timekeeper.lock, flags2);
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if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
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ts = timespec_sub(ts, timekeeping_suspend_time);
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@ -689,7 +716,8 @@ static void timekeeping_resume(void)
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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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timekeeping_suspended = 0;
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_sequnlock_irqrestore(&timekeeper.lock, flags2);
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write_sequnlock_irqrestore(&xtime_lock, flags1);
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touch_softlockup_watchdog();
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@ -701,13 +729,14 @@ static void timekeeping_resume(void)
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static int timekeeping_suspend(void)
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{
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unsigned long flags;
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unsigned long flags1,flags2;
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struct timespec delta, delta_delta;
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static struct timespec old_delta;
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read_persistent_clock(&timekeeping_suspend_time);
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write_seqlock_irqsave(&xtime_lock, flags);
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write_seqlock_irqsave(&xtime_lock, flags1);
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write_seqlock_irqsave(&timekeeper.lock, flags2);
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timekeeping_forward_now();
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timekeeping_suspended = 1;
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@ -730,7 +759,8 @@ static int timekeeping_suspend(void)
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timekeeping_suspend_time =
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timespec_add(timekeeping_suspend_time, delta_delta);
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}
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write_sequnlock_irqrestore(&xtime_lock, flags);
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write_sequnlock_irqrestore(&timekeeper.lock, flags2);
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write_sequnlock_irqrestore(&xtime_lock, flags1);
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clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
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clocksource_suspend();
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@ -983,10 +1013,13 @@ static void update_wall_time(void)
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struct clocksource *clock;
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cycle_t offset;
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int shift = 0, maxshift;
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unsigned long flags;
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write_seqlock_irqsave(&timekeeper.lock, flags);
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/* Make sure we're fully resumed: */
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if (unlikely(timekeeping_suspended))
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return;
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goto out;
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clock = timekeeper.clock;
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@ -1067,6 +1100,10 @@ static void update_wall_time(void)
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/* check to see if there is a new clocksource to use */
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update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
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timekeeper.clock, timekeeper.mult);
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out:
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write_sequnlock_irqrestore(&timekeeper.lock, flags);
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}
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/**
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@ -1112,13 +1149,13 @@ void get_monotonic_boottime(struct timespec *ts)
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WARN_ON(timekeeping_suspended);
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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*ts = timekeeper.xtime;
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tomono = timekeeper.wall_to_monotonic;
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sleep = timekeeper.total_sleep_time;
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nsecs = timekeeping_get_ns();
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec,
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ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs);
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@ -1169,10 +1206,10 @@ struct timespec current_kernel_time(void)
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unsigned long seq;
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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now = timekeeper.xtime;
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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return now;
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}
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@ -1184,11 +1221,11 @@ struct timespec get_monotonic_coarse(void)
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unsigned long seq;
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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now = timekeeper.xtime;
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mono = timekeeper.wall_to_monotonic;
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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set_normalized_timespec(&now, now.tv_sec + mono.tv_sec,
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now.tv_nsec + mono.tv_nsec);
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@ -1220,11 +1257,11 @@ void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim,
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unsigned long seq;
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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*xtim = timekeeper.xtime;
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*wtom = timekeeper.wall_to_monotonic;
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*sleep = timekeeper.total_sleep_time;
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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}
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/**
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@ -1236,9 +1273,10 @@ ktime_t ktime_get_monotonic_offset(void)
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struct timespec wtom;
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do {
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seq = read_seqbegin(&xtime_lock);
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seq = read_seqbegin(&timekeeper.lock);
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wtom = timekeeper.wall_to_monotonic;
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} while (read_seqretry(&xtime_lock, seq));
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} while (read_seqretry(&timekeeper.lock, seq));
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return timespec_to_ktime(wtom);
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}
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