sched / idle: Eliminate the "reflect" check from cpuidle_idle_call()

Since cpuidle_reflect() should only be called if the idle state
to enter was selected by cpuidle_select(), there is the "reflect"
variable in cpuidle_idle_call() whose value is used to determine
whether or not that is the case.

However, if the entire code run between the conditional setting
"reflect" and the call to cpuidle_reflect() is moved to a separate
function, it will be possible to call that new function in both
branches of the conditional, in which case cpuidle_reflect() will
only need to be called from one of them too and the "reflect"
variable won't be necessary any more.

This eliminates one check made by cpuidle_idle_call() on the majority
of its invocations, so change the code as described.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index ae7c0be90d16d6301402ce3df7e1deacbeea5792..9c919b42f8465fe76aeda5845c2560ca13127146 100644 (file)
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -79,6 +79,46 @@ static void default_idle_call(void)
                arch_cpu_idle();
 }
 
+static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+                     int next_state)
+{
+       int entered_state;
+
+       /* Fall back to the default arch idle method on errors. */
+       if (next_state < 0) {
+               default_idle_call();
+               return next_state;
+       }
+
+       /*
+        * The idle task must be scheduled, it is pointless to go to idle, just
+        * update no idle residency and return.
+        */
+       if (current_clr_polling_and_test()) {
+               dev->last_residency = 0;
+               local_irq_enable();
+               return -EBUSY;
+       }
+
+       /* Take note of the planned idle state. */
+       idle_set_state(this_rq(), &drv->states[next_state]);
+
+       /*
+        * Enter the idle state previously returned by the governor decision.
+        * This function will block until an interrupt occurs and will take
+        * care of re-enabling the local interrupts
+        */
+       entered_state = cpuidle_enter(drv, dev, next_state);
+
+       /* The cpu is no longer idle or about to enter idle. */
+       idle_set_state(this_rq(), NULL);
+
+       if (entered_state == -EBUSY)
+               default_idle_call();
+
+       return entered_state;
+}
+
 /**
  * cpuidle_idle_call - the main idle function
  *
@@ -93,7 +133,6 @@ static void cpuidle_idle_call(void)
        struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
        struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
        int next_state, entered_state;
-       bool reflect;
 
        /*
         * Check if the idle task must be rescheduled. If it is the
@@ -138,56 +177,19 @@ static void cpuidle_idle_call(void)
                        goto exit_idle;
                }
 
-               reflect = false;
                next_state = cpuidle_find_deepest_state(drv, dev);
+               call_cpuidle(drv, dev, next_state);
        } else {
-               reflect = true;
                /*
                 * Ask the cpuidle framework to choose a convenient idle state.
                 */
                next_state = cpuidle_select(drv, dev);
-       }
-       /* Fall back to the default arch idle method on errors. */
-       if (next_state < 0) {
-               default_idle_call();
-               goto exit_idle;
-       }
-
-       /*
-        * The idle task must be scheduled, it is pointless to
-        * go to idle, just update no idle residency and get
-        * out of this function
-        */
-       if (current_clr_polling_and_test()) {
-               dev->last_residency = 0;
-               entered_state = next_state;
-               local_irq_enable();
-               goto exit_idle;
-       }
-
-       /* Take note of the planned idle state. */
-       idle_set_state(this_rq(), &drv->states[next_state]);
-
-       /*
-        * Enter the idle state previously returned by the governor decision.
-        * This function will block until an interrupt occurs and will take
-        * care of re-enabling the local interrupts
-        */
-       entered_state = cpuidle_enter(drv, dev, next_state);
-
-       /* The cpu is no longer idle or about to enter idle. */
-       idle_set_state(this_rq(), NULL);
-
-       if (entered_state == -EBUSY) {
-               default_idle_call();
-               goto exit_idle;
-       }
-
-       /*
-        * Give the governor an opportunity to reflect on the outcome
-        */
-       if (reflect)
+               entered_state = call_cpuidle(drv, dev, next_state);
+               /*
+                * Give the governor an opportunity to reflect on the outcome
+                */
                cpuidle_reflect(dev, entered_state);
+       }
 
 exit_idle:
        __current_set_polling();