[hrtimer] Change resolution storage to ktime_t format

Change the storage format of the per base resolution to ktime_t to
make it easier accessible in the hrtimers code.

Change the resolution from (NSEC_PER_SEC/HZ) to TICK_NSEC as Roman
pointed out. TICK_NSEC is closer to the real resolution.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/hrtimer.h

@@ -85,7 +85,7 @@ struct hrtimer_base {
 	spinlock_t		lock;
 	struct rb_root		active;
 	struct rb_node		*first;
-	unsigned long		resolution;
+	ktime_t			resolution;
 	ktime_t			(*get_time)(void);
 	struct hrtimer		*curr_timer;
 };

include/linux/ktime.h

@@ -272,8 +272,8 @@ static inline u64 ktime_to_ns(const ktime_t kt)
  * idea of the (in)accuracy of timers. Timer values are rounded up to
  * this resolution values.
  */
-#define KTIME_REALTIME_RES	(NSEC_PER_SEC/HZ)
-#define KTIME_MONOTONIC_RES	(NSEC_PER_SEC/HZ)
+#define KTIME_REALTIME_RES	(ktime_t){ .tv64 = TICK_NSEC }
+#define KTIME_MONOTONIC_RES	(ktime_t){ .tv64 = TICK_NSEC }
 
 /* Get the monotonic time in timespec format: */
 extern void ktime_get_ts(struct timespec *ts);

kernel/hrtimer.c

@@ -518,9 +518,8 @@ int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
 {
 	struct hrtimer_base *bases;
 
-	tp->tv_sec = 0;
 	bases = per_cpu(hrtimer_bases, raw_smp_processor_id());
-	tp->tv_nsec = bases[which_clock].resolution;
+	*tp = ktime_to_timespec(bases[which_clock].resolution);
 
 	return 0;
 }