/* xtime and wall_jiffies keep wall-clock time */
extern unsigned long wall_jiffies;
-static long clocktick; /* timer cycles per tick */
-static long halftick;
+static long clocktick __read_mostly; /* timer cycles per tick */
+static long halftick __read_mostly;
#ifdef CONFIG_SMP
extern void smp_do_timer(struct pt_regs *regs);