time_interpolator: add __read_mostly

The pointer to the current time interpolator and the current list of
time interpolators are typically only changed during bootup. Adding
__read_mostly takes them away from possible hot cachelines.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.16-rc6/kernel/timer.c
===================================================================
--- linux-2.6.16-rc6.orig/kernel/timer.c	2006-03-11 14:12:55.000000000 -0800
+++ linux-2.6.16-rc6/kernel/timer.c	2006-03-15 16:13:05.000000000 -0800
@@ -1354,8 +1354,8 @@ void __init init_timers(void)
 
 #ifdef CONFIG_TIME_INTERPOLATION
 
-struct time_interpolator *time_interpolator;
-static struct time_interpolator *time_interpolator_list;
+struct time_interpolator *time_interpolator __read_mostly;
+static struct time_interpolator *time_interpolator_list __read_mostly;
 static DEFINE_SPINLOCK(time_interpolator_lock);
 
 static inline u64 time_interpolator_get_cycles(unsigned int src)