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

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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>
This commit is contained in:
Rafael J. Wysocki 2015-05-04 22:53:35 +02:00
parent a802ea9645
commit bcf6ad8a4a
1 changed files with 46 additions and 44 deletions
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84
kernel/sched/idle.c
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@ -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;
}
entered_state = call_cpuidle(drv, dev, next_state);
/*
* Give the governor an opportunity to reflect on the outcome
*/
if (reflect)
cpuidle_reflect(dev, entered_state);
}
exit_idle:
__current_set_polling();