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Commit 7c032df5 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by John Stultz
Browse files

timekeeping: Provide internal ktime_t based data 



The ktime_t based interfaces are used a lot in performance critical
code pathes. Add ktime_t based data so the interfaces don't have to
convert from the xtime/timespec based data.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent f111adfd

include/linux/timekeeper_internal.h

+3 −0
Original line number Diff line number Diff line
@@ -36,6 +36,9 @@ struct timekeeper { 
	/* Clock shifted nano seconds */

	u64			xtime_nsec;



	/* Monotonic base time */

	ktime_t			base_mono;



	/* Current CLOCK_REALTIME time in seconds */

	u64			xtime_sec;

	/* CLOCK_REALTIME to CLOCK_MONOTONIC offset */

kernel/time/timekeeping.c

+22 −0
Original line number Diff line number Diff line
@@ -291,6 +291,26 @@ int pvclock_gtod_unregister_notifier(struct notifier_block *nb) 
}

EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);



/*

 * Update the ktime_t based scalar nsec members of the timekeeper

 */

static inline void tk_update_ktime_data(struct timekeeper *tk)

{

	s64 nsec;



	/*

	 * The xtime based monotonic readout is:

	 *	nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();

	 * The ktime based monotonic readout is:

	 *	nsec = base_mono + now();

	 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec

	 */

	nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);

	nsec *= NSEC_PER_SEC;

	nsec += tk->wall_to_monotonic.tv_nsec;

	tk->base_mono = ns_to_ktime(nsec);

}



/* must hold timekeeper_lock */

static void timekeeping_update(struct timekeeper *tk, unsigned int action)

{
@@ -301,6 +321,8 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action) 
	update_vsyscall(tk);

	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);



	tk_update_ktime_data(tk);



	if (action & TK_MIRROR)

		memcpy(&shadow_timekeeper, &tk_core.timekeeper,

		       sizeof(tk_core.timekeeper));