timekeeping: Split timekeeper_lock into lock and seqcount
We want to shorten the seqcount write hold time. So split the seqlock into a lock and a seqcount. Open code the seqwrite_lock in the places which matter and drop the sequence counter update where it's pointless. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [jstultz: Merge fixups from CLOCK_TAI collisions] Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Thomas Gleixner
John Stultz
parent
7e40672d93
commit
9a7a71b1d0
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@ -26,7 +26,8 @@
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#include "tick-internal.h"
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static struct timekeeper timekeeper;
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static DEFINE_SEQLOCK(timekeeper_lock);
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static DEFINE_RAW_SPINLOCK(timekeeper_lock);
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static seqcount_t timekeeper_seq;
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/* flag for if timekeeping is suspended */
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int __read_mostly timekeeping_suspended;
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@ -204,8 +205,6 @@ static void update_pvclock_gtod(struct timekeeper *tk)
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/**
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* pvclock_gtod_register_notifier - register a pvclock timedata update listener
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*
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* Must hold write on timekeeper.lock
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*/
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int pvclock_gtod_register_notifier(struct notifier_block *nb)
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{
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@ -213,11 +212,10 @@ int pvclock_gtod_register_notifier(struct notifier_block *nb)
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unsigned long flags;
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int ret;
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
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/* update timekeeping data */
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update_pvclock_gtod(tk);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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return ret;
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}
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@ -226,23 +224,21 @@ EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
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/**
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* pvclock_gtod_unregister_notifier - unregister a pvclock
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* timedata update listener
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*
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* Must hold write on timekeeper.lock
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*/
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int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
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{
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unsigned long flags;
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int ret;
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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return ret;
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}
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EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
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/* must hold write on timekeeper.lock */
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/* must hold timekeeper_lock */
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static void timekeeping_update(struct timekeeper *tk, bool clearntp)
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{
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if (clearntp) {
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@ -296,12 +292,12 @@ int __getnstimeofday(struct timespec *ts)
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s64 nsecs = 0;
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ts->tv_sec = tk->xtime_sec;
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nsecs = timekeeping_get_ns(tk);
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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ts->tv_nsec = 0;
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timespec_add_ns(ts, nsecs);
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@ -337,11 +333,11 @@ 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(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
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nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, 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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@ -368,12 +364,12 @@ 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(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ts->tv_sec = tk->xtime_sec;
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nsec = timekeeping_get_ns(tk);
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tomono = tk->wall_to_monotonic;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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ts->tv_sec += tomono.tv_sec;
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ts->tv_nsec = 0;
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@ -397,12 +393,12 @@ void timekeeping_clocktai(struct timespec *ts)
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WARN_ON(timekeeping_suspended);
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ts->tv_sec = tk->xtime_sec + tk->tai_offset;
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nsecs = timekeeping_get_ns(tk);
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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ts->tv_nsec = 0;
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timespec_add_ns(ts, nsecs);
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@ -445,7 +441,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
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WARN_ON_ONCE(timekeeping_suspended);
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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*ts_raw = tk->raw_time;
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ts_real->tv_sec = tk->xtime_sec;
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@ -454,7 +450,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
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nsecs_raw = timekeeping_get_ns_raw(tk);
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nsecs_real = timekeeping_get_ns(tk);
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, 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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@ -494,7 +490,8 @@ int do_settimeofday(const struct timespec *tv)
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if (!timespec_valid_strict(tv))
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return -EINVAL;
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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timekeeping_forward_now(tk);
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@ -508,7 +505,8 @@ int do_settimeofday(const struct timespec *tv)
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timekeeping_update(tk, true);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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/* signal hrtimers about time change */
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clock_was_set();
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@ -533,7 +531,8 @@ int timekeeping_inject_offset(struct timespec *ts)
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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(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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timekeeping_forward_now(tk);
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@ -550,7 +549,8 @@ int timekeeping_inject_offset(struct timespec *ts)
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error: /* even if we error out, we forwarded the time, so call update */
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timekeeping_update(tk, true);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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/* signal hrtimers about time change */
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clock_was_set();
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@ -571,9 +571,9 @@ s32 timekeeping_get_tai_offset(void)
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s32 ret;
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ret = tk->tai_offset;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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return ret;
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}
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@ -597,9 +597,11 @@ void timekeeping_set_tai_offset(s32 tai_offset)
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struct timekeeper *tk = &timekeeper;
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unsigned long flags;
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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__timekeeping_set_tai_offset(tk, tai_offset);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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}
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/**
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@ -615,7 +617,8 @@ static int change_clocksource(void *data)
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new = (struct clocksource *) data;
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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timekeeping_forward_now(tk);
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if (!new->enable || new->enable(new) == 0) {
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@ -626,7 +629,8 @@ static int change_clocksource(void *data)
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}
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timekeeping_update(tk, true);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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return 0;
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}
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@ -676,11 +680,11 @@ void getrawmonotonic(struct timespec *ts)
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s64 nsecs;
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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nsecs = timekeeping_get_ns_raw(tk);
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*ts = tk->raw_time;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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timespec_add_ns(ts, nsecs);
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}
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@ -696,11 +700,11 @@ int timekeeping_valid_for_hres(void)
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int ret;
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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return ret;
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}
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@ -715,11 +719,11 @@ u64 timekeeping_max_deferment(void)
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u64 ret;
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do {
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seq = read_seqbegin(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ret = tk->clock->max_idle_ns;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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return ret;
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}
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@ -784,7 +788,8 @@ void __init timekeeping_init(void)
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ntp_init();
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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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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@ -803,7 +808,8 @@ void __init timekeeping_init(void)
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tmp.tv_nsec = 0;
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tk_set_sleep_time(tk, tmp);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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}
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/* time in seconds when suspend began */
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@ -851,7 +857,8 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
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if (has_persistent_clock())
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return;
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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timekeeping_forward_now(tk);
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@ -859,7 +866,8 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
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timekeeping_update(tk, true);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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/* signal hrtimers about time change */
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clock_was_set();
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@ -886,7 +894,8 @@ static void timekeeping_resume(void)
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clockevents_resume();
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clocksource_resume();
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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/*
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* After system resumes, we need to calculate the suspended time and
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@ -938,7 +947,8 @@ static void timekeeping_resume(void)
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tk->ntp_error = 0;
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timekeeping_suspended = 0;
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timekeeping_update(tk, false);
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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touch_softlockup_watchdog();
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@ -957,7 +967,8 @@ static int timekeeping_suspend(void)
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read_persistent_clock(&timekeeping_suspend_time);
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write_seqlock_irqsave(&timekeeper_lock, flags);
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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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timekeeping_forward_now(tk);
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timekeeping_suspended = 1;
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@ -980,7 +991,8 @@ 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(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
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clocksource_suspend();
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@ -1320,7 +1332,8 @@ static void update_wall_time(void)
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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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raw_spin_lock_irqsave(&timekeeper_lock, flags);
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write_seqcount_begin(&timekeeper_seq);
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/* Make sure we're fully resumed: */
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if (unlikely(timekeeping_suspended))
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@ -1375,7 +1388,8 @@ static void update_wall_time(void)
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timekeeping_update(tk, false);
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out:
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write_sequnlock_irqrestore(&timekeeper_lock, flags);
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write_seqcount_end(&timekeeper_seq);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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}
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@ -1423,13 +1437,13 @@ 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(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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ts->tv_sec = tk->xtime_sec;
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nsec = timekeeping_get_ns(tk);
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tomono = tk->wall_to_monotonic;
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sleep = tk->total_sleep_time;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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ts->tv_sec += tomono.tv_sec + sleep.tv_sec;
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ts->tv_nsec = 0;
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@ -1488,10 +1502,10 @@ 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(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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now = tk_xtime(tk);
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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return now;
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}
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@ -1504,11 +1518,11 @@ 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(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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now = tk_xtime(tk);
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mono = tk->wall_to_monotonic;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, 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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@ -1539,11 +1553,11 @@ 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(&timekeeper_lock);
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seq = read_seqcount_begin(&timekeeper_seq);
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*xtim = tk_xtime(tk);
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*wtom = tk->wall_to_monotonic;
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*sleep = tk->total_sleep_time;
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} while (read_seqretry(&timekeeper_lock, seq));
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} while (read_seqcount_retry(&timekeeper_seq, seq));
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}
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#ifdef CONFIG_HIGH_RES_TIMERS
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@ -1564,7 +1578,7 @@ ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot,
|
|||
u64 secs, nsecs;
|
||||
|
||||
do {
|
||||
seq = read_seqbegin(&timekeeper_lock);
|
||||
seq = read_seqcount_begin(&timekeeper_seq);
|
||||
|
||||
secs = tk->xtime_sec;
|
||||
nsecs = timekeeping_get_ns(tk);
|
||||
|
|
@ -1572,7 +1586,7 @@ ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot,
|
|||
*offs_real = tk->offs_real;
|
||||
*offs_boot = tk->offs_boot;
|
||||
*offs_tai = tk->offs_tai;
|
||||
} while (read_seqretry(&timekeeper_lock, seq));
|
||||
} while (read_seqcount_retry(&timekeeper_seq, seq));
|
||||
|
||||
now = ktime_add_ns(ktime_set(secs, 0), nsecs);
|
||||
now = ktime_sub(now, *offs_real);
|
||||
|
|
@ -1590,9 +1604,9 @@ ktime_t ktime_get_monotonic_offset(void)
|
|||
struct timespec wtom;
|
||||
|
||||
do {
|
||||
seq = read_seqbegin(&timekeeper_lock);
|
||||
seq = read_seqcount_begin(&timekeeper_seq);
|
||||
wtom = tk->wall_to_monotonic;
|
||||
} while (read_seqretry(&timekeeper_lock, seq));
|
||||
} while (read_seqcount_retry(&timekeeper_seq, seq));
|
||||
|
||||
return timespec_to_ktime(wtom);
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue