| Subject: timekeeping-split-jiffies-lock.patch |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Thu, 14 Feb 2013 22:36:59 +0100 |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| kernel/time/jiffies.c | 7 ++++--- |
| kernel/time/tick-common.c | 10 ++++++---- |
| kernel/time/tick-internal.h | 3 ++- |
| kernel/time/tick-sched.c | 16 ++++++++++------ |
| kernel/time/timekeeping.c | 6 ++++-- |
| 5 files changed, 26 insertions(+), 16 deletions(-) |
| |
| --- a/kernel/time/jiffies.c |
| +++ b/kernel/time/jiffies.c |
| @@ -67,7 +67,8 @@ static struct clocksource clocksource_ji |
| .shift = JIFFIES_SHIFT, |
| }; |
| |
| -__cacheline_aligned_in_smp DEFINE_SEQLOCK(jiffies_lock); |
| +__cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(jiffies_lock); |
| +__cacheline_aligned_in_smp seqcount_t jiffies_seq; |
| |
| #if (BITS_PER_LONG < 64) |
| u64 get_jiffies_64(void) |
| @@ -76,9 +77,9 @@ u64 get_jiffies_64(void) |
| u64 ret; |
| |
| do { |
| - seq = read_seqbegin(&jiffies_lock); |
| + seq = read_seqcount_begin(&jiffies_seq); |
| ret = jiffies_64; |
| - } while (read_seqretry(&jiffies_lock, seq)); |
| + } while (read_seqcount_retry(&jiffies_seq, seq)); |
| return ret; |
| } |
| EXPORT_SYMBOL(get_jiffies_64); |
| --- 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(&jiffies_lock); |
| + raw_spin_lock(&jiffies_lock); |
| + write_seqcount_begin(&jiffies_seq); |
| |
| /* Keep track of the next tick event */ |
| tick_next_period = ktime_add(tick_next_period, tick_period); |
| |
| do_timer(1); |
| - write_sequnlock(&jiffies_lock); |
| + write_seqcount_end(&jiffies_seq); |
| + raw_spin_unlock(&jiffies_lock); |
| } |
| |
| update_process_times(user_mode(get_irq_regs())); |
| @@ -130,9 +132,9 @@ void tick_setup_periodic(struct clock_ev |
| ktime_t next; |
| |
| do { |
| - seq = read_seqbegin(&jiffies_lock); |
| + seq = read_seqcount_begin(&jiffies_seq); |
| next = tick_next_period; |
| - } while (read_seqretry(&jiffies_lock, seq)); |
| + } while (read_seqcount_retry(&jiffies_seq, seq)); |
| |
| clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT); |
| |
| --- a/kernel/time/tick-internal.h |
| +++ b/kernel/time/tick-internal.h |
| @@ -4,7 +4,8 @@ |
| #include <linux/hrtimer.h> |
| #include <linux/tick.h> |
| |
| -extern seqlock_t jiffies_lock; |
| +extern raw_spinlock_t jiffies_lock; |
| +extern seqcount_t jiffies_seq; |
| |
| #ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD |
| |
| --- a/kernel/time/tick-sched.c |
| +++ b/kernel/time/tick-sched.c |
| @@ -61,7 +61,8 @@ static void tick_do_update_jiffies64(kti |
| return; |
| |
| /* Reevalute with jiffies_lock held */ |
| - write_seqlock(&jiffies_lock); |
| + raw_spin_lock(&jiffies_lock); |
| + write_seqcount_begin(&jiffies_seq); |
| |
| delta = ktime_sub(now, last_jiffies_update); |
| if (delta.tv64 >= tick_period.tv64) { |
| @@ -84,7 +85,8 @@ static void tick_do_update_jiffies64(kti |
| /* Keep the tick_next_period variable up to date */ |
| tick_next_period = ktime_add(last_jiffies_update, tick_period); |
| } |
| - write_sequnlock(&jiffies_lock); |
| + write_seqcount_end(&jiffies_seq); |
| + raw_spin_unlock(&jiffies_lock); |
| } |
| |
| /* |
| @@ -94,12 +96,14 @@ static ktime_t tick_init_jiffy_update(vo |
| { |
| ktime_t period; |
| |
| - write_seqlock(&jiffies_lock); |
| + raw_spin_lock(&jiffies_lock); |
| + write_seqcount_begin(&jiffies_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(&jiffies_lock); |
| + write_seqcount_end(&jiffies_seq); |
| + raw_spin_unlock(&jiffies_lock); |
| return period; |
| } |
| |
| @@ -547,11 +551,11 @@ static ktime_t tick_nohz_stop_sched_tick |
| |
| /* Read jiffies and the time when jiffies were updated last */ |
| do { |
| - seq = read_seqbegin(&jiffies_lock); |
| + seq = read_seqcount_begin(&jiffies_seq); |
| last_update = last_jiffies_update; |
| last_jiffies = jiffies; |
| time_delta = timekeeping_max_deferment(); |
| - } while (read_seqretry(&jiffies_lock, seq)); |
| + } while (read_seqcount_retry(&jiffies_seq, seq)); |
| |
| if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || |
| arch_needs_cpu(cpu) || irq_work_needs_cpu()) { |
| --- a/kernel/time/timekeeping.c |
| +++ b/kernel/time/timekeeping.c |
| @@ -1712,7 +1712,9 @@ EXPORT_SYMBOL(hardpps); |
| */ |
| void xtime_update(unsigned long ticks) |
| { |
| - write_seqlock(&jiffies_lock); |
| + raw_spin_lock(&jiffies_lock); |
| + write_seqcount_begin(&jiffies_seq); |
| do_timer(ticks); |
| - write_sequnlock(&jiffies_lock); |
| + write_seqcount_end(&jiffies_seq); |
| + raw_spin_unlock(&jiffies_lock); |
| } |