sched/fair: Remove idle_balance() declaration in sched.h

Remove idle_balance() from the public life; also reduce some #ifdef
clutter by folding the pick_next_task_fair() idle path into
idle_balance().

Cc: mingo@kernel.org
Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140211151148.GP27965@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 280da89..40c758b 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2374,13 +2374,13 @@ static inline void __update_group_entity_contrib(struct sched_entity *se)
                se->avg.load_avg_contrib >>= NICE_0_SHIFT;
        }
 }
-#else
+#else /* CONFIG_FAIR_GROUP_SCHED */
 static inline void __update_cfs_rq_tg_load_contrib(struct cfs_rq *cfs_rq,
                                                 int force_update) {}
 static inline void __update_tg_runnable_avg(struct sched_avg *sa,
                                                  struct cfs_rq *cfs_rq) {}
 static inline void __update_group_entity_contrib(struct sched_entity *se) {}
-#endif
+#endif /* CONFIG_FAIR_GROUP_SCHED */
 
 static inline void __update_task_entity_contrib(struct sched_entity *se)
 {
@@ -2571,6 +2571,8 @@ void idle_exit_fair(struct rq *this_rq)
        update_rq_runnable_avg(this_rq, 0);
 }
 
+static int idle_balance(struct rq *this_rq);
+
 #else /* CONFIG_SMP */
 
 static inline void update_entity_load_avg(struct sched_entity *se,
@@ -2584,6 +2586,12 @@ static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq,
                                           int sleep) {}
 static inline void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq,
                                              int force_update) {}
+
+static inline int idle_balance(struct rq *rq)
+{
+       return 0;
+}
+
 #endif /* CONFIG_SMP */
 
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -4677,7 +4685,7 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev)
        struct sched_entity *se;
        struct task_struct *p;
 
-again: __maybe_unused
+again:
 #ifdef CONFIG_FAIR_GROUP_SCHED
        if (!cfs_rq->nr_running)
                goto idle;
@@ -4775,18 +4783,8 @@ simple:
        return p;
 
 idle:
-#ifdef CONFIG_SMP
-       idle_enter_fair(rq);
-       /*
-        * We must set idle_stamp _before_ calling idle_balance(), such that we
-        * measure the duration of idle_balance() as idle time.
-        */
-       rq->idle_stamp = rq_clock(rq);
-       if (idle_balance(rq)) { /* drops rq->lock */
-               rq->idle_stamp = 0;
+       if (idle_balance(rq)) /* drops rq->lock */
                goto again;
-       }
-#endif
 
        return NULL;
 }
@@ -6634,7 +6632,7 @@ out:
  * idle_balance is called by schedule() if this_cpu is about to become
  * idle. Attempts to pull tasks from other CPUs.
  */
-int idle_balance(struct rq *this_rq)
+static int idle_balance(struct rq *this_rq)
 {
        struct sched_domain *sd;
        int pulled_task = 0;
@@ -6642,8 +6640,15 @@ int idle_balance(struct rq *this_rq)
        u64 curr_cost = 0;
        int this_cpu = this_rq->cpu;
 
+       idle_enter_fair(this_rq);
+       /*
+        * We must set idle_stamp _before_ calling idle_balance(), such that we
+        * measure the duration of idle_balance() as idle time.
+        */
+       this_rq->idle_stamp = rq_clock(this_rq);
+
        if (this_rq->avg_idle < sysctl_sched_migration_cost)
-               return 0;
+               goto out;
 
        /*
         * Drop the rq->lock, but keep IRQ/preempt disabled.
@@ -6692,8 +6697,10 @@ int idle_balance(struct rq *this_rq)
         * While browsing the domains, we released the rq lock.
         * A task could have be enqueued in the meantime
         */
-       if (this_rq->nr_running && !pulled_task)
-               return 1;
+       if (this_rq->nr_running && !pulled_task) {
+               pulled_task = 1;
+               goto out;
+       }
 
        if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
                /*
@@ -6706,6 +6713,10 @@ int idle_balance(struct rq *this_rq)
        if (curr_cost > this_rq->max_idle_balance_cost)
                this_rq->max_idle_balance_cost = curr_cost;
 
+out:
+       if (pulled_task)
+               this_rq->idle_stamp = 0;
+
        return pulled_task;
 }
 

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 1bf34c2..92018f9 100644 (file)
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1163,17 +1163,10 @@ extern const struct sched_class idle_sched_class;
 extern void update_group_power(struct sched_domain *sd, int cpu);
 
 extern void trigger_load_balance(struct rq *rq);
-extern int idle_balance(struct rq *this_rq);
 
 extern void idle_enter_fair(struct rq *this_rq);
 extern void idle_exit_fair(struct rq *this_rq);
 
-#else  /* CONFIG_SMP */
-
-static inline void idle_balance(int cpu, struct rq *rq)
-{
-}
-
 #endif
 
 extern void sysrq_sched_debug_show(void);