Merge branch 'x86/cpu' into x86/core

[linux-2.6-omap-h63xx.git] / drivers / cpuidle / governors / menu.c

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 78d77c5dc35c3ec00b261fa39a7e3aa89271a957..8d7cf3f31450728ab60a3f349f2e9f88b00cfb95 100644 (file)
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -34,21 +34,28 @@ static DEFINE_PER_CPU(struct menu_device, menu_devices);
 static int menu_select(struct cpuidle_device *dev)
 {
        struct menu_device *data = &__get_cpu_var(menu_devices);
+       int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
        int i;
 
+       /* Special case when user has set very strict latency requirement */
+       if (unlikely(latency_req == 0)) {
+               data->last_state_idx = 0;
+               return 0;
+       }
+
        /* determine the expected residency time */
        data->expected_us =
                (u32) ktime_to_ns(tick_nohz_get_sleep_length()) / 1000;
 
        /* find the deepest idle state that satisfies our constraints */
-       for (i = 1; i < dev->state_count; i++) {
+       for (i = CPUIDLE_DRIVER_STATE_START + 1; i < dev->state_count; i++) {
                struct cpuidle_state *s = &dev->states[i];
 
                if (s->target_residency > data->expected_us)
                        break;
                if (s->target_residency > data->predicted_us)
                        break;
-               if (s->exit_latency > pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY))
+               if (s->exit_latency > latency_req)
                        break;
        }
 
@@ -67,9 +74,9 @@ static void menu_reflect(struct cpuidle_device *dev)
 {
        struct menu_device *data = &__get_cpu_var(menu_devices);
        int last_idx = data->last_state_idx;
-       unsigned int measured_us =
-               cpuidle_get_last_residency(dev) + data->elapsed_us;
+       unsigned int last_idle_us = cpuidle_get_last_residency(dev);
        struct cpuidle_state *target = &dev->states[last_idx];
+       unsigned int measured_us;
 
        /*
         * Ugh, this idle state doesn't support residency measurements, so we
@@ -77,20 +84,27 @@ static void menu_reflect(struct cpuidle_device *dev)
         * for one full standard timer tick.  However, be aware that this
         * could potentially result in a suboptimal state transition.
         */
-       if (!(target->flags & CPUIDLE_FLAG_TIME_VALID))
-               measured_us = USEC_PER_SEC / HZ;
+       if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID)))
+               last_idle_us = USEC_PER_SEC / HZ;
+
+       /*
+        * measured_us and elapsed_us are the cumulative idle time, since the
+        * last time we were woken out of idle by an interrupt.
+        */
+       if (data->elapsed_us <= data->elapsed_us + last_idle_us)
+               measured_us = data->elapsed_us + last_idle_us;
+       else
+               measured_us = -1;
+
+       /* Predict time until next break event */
+       data->predicted_us = max(measured_us, data->last_measured_us);
 
-       /* Predict time remaining until next break event */
-       if (measured_us + BREAK_FUZZ < data->expected_us - target->exit_latency) {
-               data->predicted_us = max(measured_us, data->last_measured_us);
+       if (last_idle_us + BREAK_FUZZ <
+           data->expected_us - target->exit_latency) {
                data->last_measured_us = measured_us;
                data->elapsed_us = 0;
        } else {
-               if (data->elapsed_us < data->elapsed_us + measured_us)
-                       data->elapsed_us = measured_us;
-               else
-                       data->elapsed_us = -1;
-               data->predicted_us = max(measured_us, data->last_measured_us);
+               data->elapsed_us = measured_us;
        }
 }