[PATCH] time_interpolator: add __read_mostly

[linux-2.6-omap-h63xx.git] / kernel / timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index 4f1cb0ab5251aed2b690003527a26258e15c49a0..2410c18dbeb1403eafac5449b48676cd6580a387 100644 (file)
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -489,13 +489,25 @@ unsigned long next_timer_interrupt(void)
        struct list_head *list;
        struct timer_list *nte;
        unsigned long expires;
+       unsigned long hr_expires = MAX_JIFFY_OFFSET;
+       ktime_t hr_delta;
        tvec_t *varray[4];
        int i, j;
 
+       hr_delta = hrtimer_get_next_event();
+       if (hr_delta.tv64 != KTIME_MAX) {
+               struct timespec tsdelta;
+               tsdelta = ktime_to_timespec(hr_delta);
+               hr_expires = timespec_to_jiffies(&tsdelta);
+               if (hr_expires < 3)
+                       return hr_expires + jiffies;
+       }
+       hr_expires += jiffies;
+
        base = &__get_cpu_var(tvec_bases);
        spin_lock(&base->t_base.lock);
        expires = base->timer_jiffies + (LONG_MAX >> 1);
-       list = 0;
+       list = NULL;
 
        /* Look for timer events in tv1. */
        j = base->timer_jiffies & TVR_MASK;
@@ -542,6 +554,10 @@ found:
                }
        }
        spin_unlock(&base->t_base.lock);
+
+       if (time_before(hr_expires, expires))
+               return hr_expires;
+
        return expires;
 }
 #endif
@@ -717,12 +733,16 @@ static void second_overflow(void)
 #endif
 }
 
-/* in the NTP reference this is called "hardclock()" */
-static void update_wall_time_one_tick(void)
+/*
+ * Returns how many microseconds we need to add to xtime this tick
+ * in doing an adjustment requested with adjtime.
+ */
+static long adjtime_adjustment(void)
 {
-       long time_adjust_step, delta_nsec;
+       long time_adjust_step;
 
-       if ((time_adjust_step = time_adjust) != 0 ) {
+       time_adjust_step = time_adjust;
+       if (time_adjust_step) {
                /*
                 * We are doing an adjtime thing.  Prepare time_adjust_step to
                 * be within bounds.  Note that a positive time_adjust means we
@@ -733,10 +753,19 @@ static void update_wall_time_one_tick(void)
                 */
                time_adjust_step = min(time_adjust_step, (long)tickadj);
                time_adjust_step = max(time_adjust_step, (long)-tickadj);
+       }
+       return time_adjust_step;
+}
 
+/* in the NTP reference this is called "hardclock()" */
+static void update_wall_time_one_tick(void)
+{
+       long time_adjust_step, delta_nsec;
+
+       time_adjust_step = adjtime_adjustment();
+       if (time_adjust_step)
                /* Reduce by this step the amount of time left  */
                time_adjust -= time_adjust_step;
-       }
        delta_nsec = tick_nsec + time_adjust_step * 1000;
        /*
         * Advance the phase, once it gets to one microsecond, then
@@ -758,6 +787,22 @@ static void update_wall_time_one_tick(void)
        }
 }
 
+/*
+ * Return how long ticks are at the moment, that is, how much time
+ * update_wall_time_one_tick will add to xtime next time we call it
+ * (assuming no calls to do_adjtimex in the meantime).
+ * The return value is in fixed-point nanoseconds with SHIFT_SCALE-10
+ * bits to the right of the binary point.
+ * This function has no side-effects.
+ */
+u64 current_tick_length(void)
+{
+       long delta_nsec;
+
+       delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
+       return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
+}
+
 /*
  * Using a loop looks inefficient, but "ticks" is
  * usually just one (we shouldn't be losing ticks,
@@ -896,6 +941,8 @@ static inline void update_times(void)
 void do_timer(struct pt_regs *regs)
 {
        jiffies_64++;
+       /* prevent loading jiffies before storing new jiffies_64 value. */
+       barrier();
        update_times();
        softlockup_tick(regs);
 }
@@ -1307,8 +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)
@@ -1322,10 +1369,10 @@ static inline u64 time_interpolator_get_cycles(unsigned int src)
                        return x();
 
                case TIME_SOURCE_MMIO64 :
-                       return readq((void __iomem *) time_interpolator->addr);
+                       return readq_relaxed((void __iomem *)time_interpolator->addr);
 
                case TIME_SOURCE_MMIO32 :
-                       return readl((void __iomem *) time_interpolator->addr);
+                       return readl_relaxed((void __iomem *)time_interpolator->addr);
 
                default: return get_cycles();
        }