tick/timekeeping: Call update_wall_time outside the jiffies lock
Since the xtime lock was split into the timekeeping lock and the jiffies lock, we no longer need to call update_wall_time() while holding the jiffies lock. Thus, this patch splits update_wall_time() out from do_timer(). This allows us to get away from calling clock_was_set_delayed() in update_wall_time() and instead use the standard clock_was_set() call that previously would deadlock, as it causes the jiffies lock to be acquired. Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
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@ -70,6 +70,7 @@ static void tick_periodic(int cpu)
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do_timer(1);
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do_timer(1);
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write_sequnlock(&jiffies_lock);
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write_sequnlock(&jiffies_lock);
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update_wall_time();
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}
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}
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update_process_times(user_mode(get_irq_regs()));
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update_process_times(user_mode(get_irq_regs()));
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@ -155,3 +155,4 @@ static inline int tick_device_is_functional(struct clock_event_device *dev)
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#endif
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#endif
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extern void do_timer(unsigned long ticks);
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extern void do_timer(unsigned long ticks);
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extern void update_wall_time(void);
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@ -86,6 +86,7 @@ static void tick_do_update_jiffies64(ktime_t now)
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tick_next_period = ktime_add(last_jiffies_update, tick_period);
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tick_next_period = ktime_add(last_jiffies_update, tick_period);
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}
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}
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write_sequnlock(&jiffies_lock);
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write_sequnlock(&jiffies_lock);
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update_wall_time();
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}
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}
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/*
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/*
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@ -1360,7 +1360,7 @@ static inline void old_vsyscall_fixup(struct timekeeper *tk)
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* update_wall_time - Uses the current clocksource to increment the wall time
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* update_wall_time - Uses the current clocksource to increment the wall time
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*
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*
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*/
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*/
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static void update_wall_time(void)
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void update_wall_time(void)
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{
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{
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struct clocksource *clock;
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struct clocksource *clock;
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struct timekeeper *real_tk = &timekeeper;
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struct timekeeper *real_tk = &timekeeper;
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@ -1441,19 +1441,8 @@ static void update_wall_time(void)
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write_seqcount_end(&timekeeper_seq);
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write_seqcount_end(&timekeeper_seq);
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out:
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out:
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
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if (clock_was_set) {
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if (clock_set)
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/*
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clock_was_set();
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* XXX - I'd rather we just call clock_was_set(), but
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* since we're currently holding the jiffies lock, calling
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* clock_was_set would trigger an ipi which would then grab
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* the jiffies lock and we'd deadlock. :(
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* The right solution should probably be droping
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* the jiffies lock before calling update_wall_time
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* but that requires some rework of the tick sched
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* code.
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*/
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clock_was_set_delayed();
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}
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}
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}
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/**
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/**
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@ -1598,7 +1587,6 @@ struct timespec get_monotonic_coarse(void)
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void do_timer(unsigned long ticks)
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void do_timer(unsigned long ticks)
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{
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{
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jiffies_64 += ticks;
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jiffies_64 += ticks;
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update_wall_time();
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calc_global_load(ticks);
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calc_global_load(ticks);
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}
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}
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@ -1756,4 +1744,5 @@ void xtime_update(unsigned long ticks)
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write_seqlock(&jiffies_lock);
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write_seqlock(&jiffies_lock);
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do_timer(ticks);
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do_timer(ticks);
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write_sequnlock(&jiffies_lock);
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write_sequnlock(&jiffies_lock);
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update_wall_time();
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}
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}
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