From 575bc99dec3a6b5121859ec0dc56a400313c500b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 1 Mar 2012 15:14:06 +0100 Subject: [PATCH 022/267] timekeeping: Split xtime_lock xtime_lock is going to be split apart in mainline, so we can shorten the seqcount protected regions and avoid updating seqcount in some code pathes. This is a straight forward split, so we can avoid the whole mess with raw seqlocks for RT. Signed-off-by: Thomas Gleixner --- kernel/time/jiffies.c | 4 +- kernel/time/ntp.c | 24 ++++++++---- kernel/time/tick-common.c | 10 +++-- kernel/time/tick-internal.h | 3 +- kernel/time/tick-sched.c | 16 +++++--- kernel/time/timekeeping.c | 90 +++++++++++++++++++++++++------------------ 6 files changed, 88 insertions(+), 59 deletions(-) diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c index a470154..21940eb 100644 --- a/kernel/time/jiffies.c +++ b/kernel/time/jiffies.c @@ -74,9 +74,9 @@ u64 get_jiffies_64(void) u64 ret; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); ret = jiffies_64; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); return ret; } EXPORT_SYMBOL(get_jiffies_64); diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 4b85a7a..419cbaa 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -358,7 +358,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer) { enum hrtimer_restart res = HRTIMER_NORESTART; - write_seqlock(&xtime_lock); + raw_spin_lock(&xtime_lock); + write_seqcount_begin(&xtime_seq); switch (time_state) { case TIME_OK: @@ -388,7 +389,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer) break; } - write_sequnlock(&xtime_lock); + write_seqcount_end(&xtime_seq); + raw_spin_unlock(&xtime_lock); return res; } @@ -663,7 +665,8 @@ int do_adjtimex(struct timex *txc) getnstimeofday(&ts); - write_seqlock_irq(&xtime_lock); + raw_spin_lock_irq(&xtime_lock); + write_seqcount_begin(&xtime_seq); if (txc->modes & ADJ_ADJTIME) { long save_adjust = time_adjust; @@ -705,7 +708,8 @@ int do_adjtimex(struct timex *txc) /* fill PPS status fields */ pps_fill_timex(txc); - write_sequnlock_irq(&xtime_lock); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irq(&xtime_lock); txc->time.tv_sec = ts.tv_sec; txc->time.tv_usec = ts.tv_nsec; @@ -903,7 +907,8 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) pts_norm = pps_normalize_ts(*phase_ts); - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); /* clear the error bits, they will be set again if needed */ time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); @@ -916,7 +921,8 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) * just start the frequency interval */ if (unlikely(pps_fbase.tv_sec == 0)) { pps_fbase = *raw_ts; - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); return; } @@ -931,7 +937,8 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) time_status |= STA_PPSJITTER; /* restart the frequency calibration interval */ pps_fbase = *raw_ts; - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); pr_err("hardpps: PPSJITTER: bad pulse\n"); return; } @@ -948,7 +955,8 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) hardpps_update_phase(pts_norm.nsec); - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); } EXPORT_SYMBOL(hardpps); diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index da6c9ec..39de540 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -63,13 +63,15 @@ int tick_is_oneshot_available(void) static void tick_periodic(int cpu) { if (tick_do_timer_cpu == cpu) { - write_seqlock(&xtime_lock); + raw_spin_lock(&xtime_lock); + write_seqcount_begin(&xtime_seq); /* Keep track of the next tick event */ tick_next_period = ktime_add(tick_next_period, tick_period); do_timer(1); - write_sequnlock(&xtime_lock); + write_seqcount_end(&xtime_seq); + raw_spin_unlock(&xtime_lock); } update_process_times(user_mode(get_irq_regs())); @@ -130,9 +132,9 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast) ktime_t next; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); next = tick_next_period; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT); diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index 4e265b9..c91100d 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -141,4 +141,5 @@ static inline int tick_device_is_functional(struct clock_event_device *dev) #endif extern void do_timer(unsigned long ticks); -extern seqlock_t xtime_lock; +extern raw_spinlock_t xtime_lock; +extern seqcount_t xtime_seq; diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index c923640..d7abd2f 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -56,7 +56,8 @@ static void tick_do_update_jiffies64(ktime_t now) return; /* Reevalute with xtime_lock held */ - write_seqlock(&xtime_lock); + raw_spin_lock(&xtime_lock); + write_seqcount_begin(&xtime_seq); delta = ktime_sub(now, last_jiffies_update); if (delta.tv64 >= tick_period.tv64) { @@ -79,7 +80,8 @@ static void tick_do_update_jiffies64(ktime_t now) /* Keep the tick_next_period variable up to date */ tick_next_period = ktime_add(last_jiffies_update, tick_period); } - write_sequnlock(&xtime_lock); + write_seqcount_end(&xtime_seq); + raw_spin_unlock(&xtime_lock); } /* @@ -89,12 +91,14 @@ static ktime_t tick_init_jiffy_update(void) { ktime_t period; - write_seqlock(&xtime_lock); + raw_spin_lock(&xtime_lock); + write_seqcount_begin(&xtime_seq); /* Did we start the jiffies update yet ? */ if (last_jiffies_update.tv64 == 0) last_jiffies_update = tick_next_period; period = last_jiffies_update; - write_sequnlock(&xtime_lock); + write_seqcount_end(&xtime_seq); + raw_spin_unlock(&xtime_lock); return period; } @@ -345,11 +349,11 @@ void tick_nohz_stop_sched_tick(int inidle) ts->idle_calls++; /* Read jiffies and the time when jiffies were updated last */ do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); last_update = last_jiffies_update; last_jiffies = jiffies; time_delta = timekeeping_max_deferment(); - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) || arch_needs_cpu(cpu)) { diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 2378413..da9e1f9 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -139,8 +139,8 @@ static inline s64 timekeeping_get_ns_raw(void) * This read-write spinlock protects us from races in SMP while * playing with xtime. */ -__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); - +__cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(xtime_lock); +seqcount_t xtime_seq; /* * The current time @@ -222,7 +222,7 @@ void getnstimeofday(struct timespec *ts) WARN_ON(timekeeping_suspended); do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); *ts = xtime; nsecs = timekeeping_get_ns(); @@ -230,7 +230,7 @@ void getnstimeofday(struct timespec *ts) /* If arch requires, add in gettimeoffset() */ nsecs += arch_gettimeoffset(); - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); timespec_add_ns(ts, nsecs); } @@ -245,14 +245,14 @@ ktime_t ktime_get(void) WARN_ON(timekeeping_suspended); do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); secs = xtime.tv_sec + wall_to_monotonic.tv_sec; nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; nsecs += timekeeping_get_ns(); /* If arch requires, add in gettimeoffset() */ nsecs += arch_gettimeoffset(); - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); /* * Use ktime_set/ktime_add_ns to create a proper ktime on * 32-bit architectures without CONFIG_KTIME_SCALAR. @@ -278,14 +278,14 @@ void ktime_get_ts(struct timespec *ts) WARN_ON(timekeeping_suspended); do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); *ts = xtime; tomono = wall_to_monotonic; nsecs = timekeeping_get_ns(); /* If arch requires, add in gettimeoffset() */ nsecs += arch_gettimeoffset(); - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec, ts->tv_nsec + tomono.tv_nsec + nsecs); @@ -313,7 +313,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) do { u32 arch_offset; - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); *ts_raw = raw_time; *ts_real = xtime; @@ -326,7 +326,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) nsecs_raw += arch_offset; nsecs_real += arch_offset; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); timespec_add_ns(ts_raw, nsecs_raw); timespec_add_ns(ts_real, nsecs_real); @@ -365,7 +365,8 @@ int do_settimeofday(const struct timespec *tv) if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) return -EINVAL; - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); timekeeping_forward_now(); @@ -381,7 +382,8 @@ int do_settimeofday(const struct timespec *tv) update_vsyscall(&xtime, &wall_to_monotonic, timekeeper.clock, timekeeper.mult); - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); /* signal hrtimers about time change */ clock_was_set(); @@ -405,7 +407,8 @@ int timekeeping_inject_offset(struct timespec *ts) if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) return -EINVAL; - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); timekeeping_forward_now(); @@ -418,7 +421,8 @@ int timekeeping_inject_offset(struct timespec *ts) update_vsyscall(&xtime, &wall_to_monotonic, timekeeper.clock, timekeeper.mult); - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); /* signal hrtimers about time change */ clock_was_set(); @@ -490,11 +494,11 @@ void getrawmonotonic(struct timespec *ts) s64 nsecs; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); nsecs = timekeeping_get_ns_raw(); *ts = raw_time; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); timespec_add_ns(ts, nsecs); } @@ -510,11 +514,11 @@ int timekeeping_valid_for_hres(void) int ret; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); return ret; } @@ -572,7 +576,8 @@ void __init timekeeping_init(void) read_persistent_clock(&now); read_boot_clock(&boot); - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); ntp_init(); @@ -593,7 +598,8 @@ void __init timekeeping_init(void) -boot.tv_sec, -boot.tv_nsec); total_sleep_time.tv_sec = 0; total_sleep_time.tv_nsec = 0; - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); } /* time in seconds when suspend began */ @@ -640,7 +646,8 @@ void timekeeping_inject_sleeptime(struct timespec *delta) if (!(ts.tv_sec == 0 && ts.tv_nsec == 0)) return; - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); timekeeping_forward_now(); __timekeeping_inject_sleeptime(delta); @@ -650,7 +657,8 @@ void timekeeping_inject_sleeptime(struct timespec *delta) update_vsyscall(&xtime, &wall_to_monotonic, timekeeper.clock, timekeeper.mult); - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); /* signal hrtimers about time change */ clock_was_set(); @@ -673,7 +681,8 @@ static void timekeeping_resume(void) clocksource_resume(); - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) { ts = timespec_sub(ts, timekeeping_suspend_time); @@ -683,7 +692,8 @@ static void timekeeping_resume(void) timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); timekeeper.ntp_error = 0; timekeeping_suspended = 0; - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); touch_softlockup_watchdog(); @@ -701,7 +711,8 @@ static int timekeeping_suspend(void) read_persistent_clock(&timekeeping_suspend_time); - write_seqlock_irqsave(&xtime_lock, flags); + raw_spin_lock_irqsave(&xtime_lock, flags); + write_seqcount_begin(&xtime_seq); timekeeping_forward_now(); timekeeping_suspended = 1; @@ -724,7 +735,8 @@ static int timekeeping_suspend(void) timekeeping_suspend_time = timespec_add(timekeeping_suspend_time, delta_delta); } - write_sequnlock_irqrestore(&xtime_lock, flags); + write_seqcount_end(&xtime_seq); + raw_spin_unlock_irqrestore(&xtime_lock, flags); clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); clocksource_suspend(); @@ -1101,13 +1113,13 @@ void get_monotonic_boottime(struct timespec *ts) WARN_ON(timekeeping_suspended); do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); *ts = xtime; tomono = wall_to_monotonic; sleep = total_sleep_time; nsecs = timekeeping_get_ns(); - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec, ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs); @@ -1158,10 +1170,10 @@ struct timespec current_kernel_time(void) unsigned long seq; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); now = xtime; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); return now; } @@ -1173,11 +1185,11 @@ struct timespec get_monotonic_coarse(void) unsigned long seq; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); now = xtime; mono = wall_to_monotonic; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, now.tv_nsec + mono.tv_nsec); @@ -1209,11 +1221,11 @@ void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, unsigned long seq; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); *xtim = xtime; *wtom = wall_to_monotonic; *sleep = total_sleep_time; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); } /** @@ -1225,9 +1237,9 @@ ktime_t ktime_get_monotonic_offset(void) struct timespec wtom; do { - seq = read_seqbegin(&xtime_lock); + seq = read_seqcount_begin(&xtime_seq); wtom = wall_to_monotonic; - } while (read_seqretry(&xtime_lock, seq)); + } while (read_seqcount_retry(&xtime_seq, seq)); return timespec_to_ktime(wtom); } @@ -1239,7 +1251,9 @@ ktime_t ktime_get_monotonic_offset(void) */ void xtime_update(unsigned long ticks) { - write_seqlock(&xtime_lock); + raw_spin_lock(&xtime_lock); + write_seqcount_begin(&xtime_seq); do_timer(ticks); - write_sequnlock(&xtime_lock); + write_seqcount_end(&xtime_seq); + raw_spin_unlock(&xtime_lock); } -- 1.7.10