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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-05-04 22:53:35 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-05-04 22:53:35 +0200
commitbcf6ad8a4a3d002e8bc8f6639cdc119168f4e87b (patch)
tree6536efb9c4c8d199aca4118af959d79192bab716 /kernel/sched/idle.c
parenta802ea96454570f3c526dd9d7ad8c706e570444d (diff)
downloadop-kernel-dev-bcf6ad8a4a3d002e8bc8f6639cdc119168f4e87b.zip
op-kernel-dev-bcf6ad8a4a3d002e8bc8f6639cdc119168f4e87b.tar.gz
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>
Diffstat (limited to 'kernel/sched/idle.c')
-rw-r--r--kernel/sched/idle.c90
1 files changed, 46 insertions, 44 deletions
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index ae7c0be..9c919b4 100644
--- 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();
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