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Commit d6ad4187 authored by John Stultz's avatar John Stultz
Browse files

time: Kill xtime_lock, replacing it with jiffies_lock 



Now that timekeeping is protected by its own locks, rename
the xtime_lock to jifffies_lock to better describe what it
protects.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 47c8c91b

drivers/clocksource/i8253.c

+1 −1
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ static cycle_t i8253_read(struct clocksource *cs) 


	raw_spin_lock_irqsave(&i8253_lock, flags);

	/*

	 * Although our caller may have the read side of xtime_lock,

	 * Although our caller may have the read side of jiffies_lock,

	 * this is now a seqlock, and we are cheating in this routine

	 * by having side effects on state that we cannot undo if

	 * there is a collision on the seqlock and our caller has to

include/linux/jiffies.h

+2 −1
Original line number Diff line number Diff line
@@ -70,11 +70,12 @@ extern int register_refined_jiffies(long clock_tick_rate); 


/*

 * The 64-bit value is not atomic - you MUST NOT read it

 * without sampling the sequence number in xtime_lock.

 * without sampling the sequence number in jiffies_lock.

 * get_jiffies_64() will do this for you as appropriate.

 */

extern u64 __jiffy_data jiffies_64;

extern unsigned long volatile __jiffy_data jiffies;

extern seqlock_t jiffies_lock;



#if (BITS_PER_LONG < 64)

u64 get_jiffies_64(void);

kernel/time/jiffies.c

+4 −2
Original line number Diff line number Diff line
@@ -67,6 +67,8 @@ static struct clocksource clocksource_jiffies = { 
	.shift		= JIFFIES_SHIFT,

};



__cacheline_aligned_in_smp DEFINE_SEQLOCK(jiffies_lock);



#if (BITS_PER_LONG < 64)

u64 get_jiffies_64(void)

{
@@ -74,9 +76,9 @@ u64 get_jiffies_64(void) 
	u64 ret;



	do {

		seq = read_seqbegin(&xtime_lock);

		seq = read_seqbegin(&jiffies_lock);

		ret = jiffies_64;

	} while (read_seqretry(&xtime_lock, seq));

	} while (read_seqretry(&jiffies_lock, seq));

	return ret;

}

EXPORT_SYMBOL(get_jiffies_64);

kernel/time/tick-common.c

+4 −4
Original line number Diff line number Diff line
@@ -63,13 +63,13 @@ int tick_is_oneshot_available(void) 
static void tick_periodic(int cpu)

{

	if (tick_do_timer_cpu == cpu) {

		write_seqlock(&xtime_lock);

		write_seqlock(&jiffies_lock);



		/* 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_sequnlock(&jiffies_lock);

	}



	update_process_times(user_mode(get_irq_regs()));
@@ -130,9 +130,9 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast) 
		ktime_t next;



		do {

			seq = read_seqbegin(&xtime_lock);

			seq = read_seqbegin(&jiffies_lock);

			next = tick_next_period;

		} while (read_seqretry(&xtime_lock, seq));

		} while (read_seqretry(&jiffies_lock, seq));



		clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);

kernel/time/tick-internal.h

+0 −1
Original line number Diff line number Diff line
@@ -141,4 +141,3 @@ 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;