[PATCH] cpufreq: schedutil: Call sugov_update_next_freq() before check to fast_switch_enabled

[Yue Hu]

From: Yue Hu <huy...@yulong.com>

Note that sugov_update_next_freq() may return false, that means the
caller sugov_fast_switch() will do nothing except fast switch check.

Similarly, sugov_deferred_update() also has unnecessary operations
of raw_spin_{lock,unlock} in sugov_update_single_freq() for that case.

So, let's call sugov_update_next_freq() before the fast switch check
to avoid unnecessary behaviors above. Update the related interface
definitions accordingly.

Signed-off-by: Yue Hu <huy...@yulong.com>
---
 kernel/sched/cpufreq_schedutil.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 41e498b..d23e5be 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -114,19 +114,13 @@ static bool sugov_update_next_freq(struct sugov_policy 
*sg_policy, u64 time,
        return true;
 }
 
-static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
-                             unsigned int next_freq)
+static void sugov_fast_switch(struct sugov_policy *sg_policy, unsigned int 
next_freq)
 {
-       if (sugov_update_next_freq(sg_policy, time, next_freq))
-               cpufreq_driver_fast_switch(sg_policy->policy, next_freq);
+       cpufreq_driver_fast_switch(sg_policy->policy, next_freq);
 }
 
-static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time,
-                                 unsigned int next_freq)
+static void sugov_deferred_update(struct sugov_policy *sg_policy)
 {
-       if (!sugov_update_next_freq(sg_policy, time, next_freq))
-               return;
-
        if (!sg_policy->work_in_progress) {
                sg_policy->work_in_progress = true;
                irq_work_queue(&sg_policy->irq_work);
@@ -368,16 +362,19 @@ static void sugov_update_single_freq(struct 
update_util_data *hook, u64 time,
                sg_policy->cached_raw_freq = cached_freq;
        }
 
+       if (!sugov_update_next_freq(sg_policy, time, next_f))
+               return;
+
        /*
         * This code runs under rq->lock for the target CPU, so it won't run
         * concurrently on two different CPUs for the same target and it is not
         * necessary to acquire the lock in the fast switch case.
         */
        if (sg_policy->policy->fast_switch_enabled) {
-               sugov_fast_switch(sg_policy, time, next_f);
+               sugov_fast_switch(sg_policy, next_f);
        } else {
                raw_spin_lock(&sg_policy->update_lock);
-               sugov_deferred_update(sg_policy, time, next_f);
+               sugov_deferred_update(sg_policy);
                raw_spin_unlock(&sg_policy->update_lock);
        }
 }
@@ -456,12 +453,15 @@ static unsigned int sugov_next_freq_shared(struct 
sugov_cpu *sg_cpu, u64 time)
        if (sugov_should_update_freq(sg_policy, time)) {
                next_f = sugov_next_freq_shared(sg_cpu, time);
 
+               if (!sugov_update_next_freq(sg_policy, time, next_f))
+                       goto unlock;
+
                if (sg_policy->policy->fast_switch_enabled)
-                       sugov_fast_switch(sg_policy, time, next_f);
+                       sugov_fast_switch(sg_policy, next_f);
                else
-                       sugov_deferred_update(sg_policy, time, next_f);
+                       sugov_deferred_update(sg_policy);
        }
-
+unlock:
        raw_spin_unlock(&sg_policy->update_lock);
 }
 
-- 
1.9.1