sched/nohz: Clean up select_nohz_load_balancer()

There is no load_balancer to be selected now. It just sets the
state of the nohz tick to stop.

So rename the function, pass the 'cpu' as a parameter and then
remove the useless call from tick_nohz_restart_sched_tick().

[ s/set_nohz_tick_stopped/nohz_balance_enter_idle/g
  s/clear_nohz_tick_stopped/nohz_balance_exit_idle/g ]
Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1347261059-24747-1-git-send-email-alex.shi@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 60e5e38eee2a3eac108daf733e3011e046c35d06..8c38df07ac3aaf0f231aff7b8d7ae30322e515f4 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -273,11 +273,11 @@ extern void init_idle_bootup_task(struct task_struct *idle);
 extern int runqueue_is_locked(int cpu);
 
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
-extern void select_nohz_load_balancer(int stop_tick);
+extern void nohz_balance_enter_idle(int cpu);
 extern void set_cpu_sd_state_idle(void);
 extern int get_nohz_timer_target(void);
 #else
-static inline void select_nohz_load_balancer(int stop_tick) { }
+static inline void nohz_balance_enter_idle(int cpu) { }
 static inline void set_cpu_sd_state_idle(void) { }
 #endif
 

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9ae3a5b68ba491e60d02ef64851f8732cf0ba4dc..de596a2f626cbebdd5454728c6390d4fb6e06c9f 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4603,7 +4603,7 @@ static void nohz_balancer_kick(int cpu)
        return;
 }
 
-static inline void clear_nohz_tick_stopped(int cpu)
+static inline void nohz_balance_exit_idle(int cpu)
 {
        if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
                cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
@@ -4643,28 +4643,23 @@ void set_cpu_sd_state_idle(void)
 }
 
 /*
- * This routine will record that this cpu is going idle with tick stopped.
+ * This routine will record that the cpu is going idle with tick stopped.
  * This info will be used in performing idle load balancing in the future.
  */
-void select_nohz_load_balancer(int stop_tick)
+void nohz_balance_enter_idle(int cpu)
 {
-       int cpu = smp_processor_id();
-
        /*
         * If this cpu is going down, then nothing needs to be done.
         */
        if (!cpu_active(cpu))
                return;
 
-       if (stop_tick) {
-               if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
-                       return;
+       if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
+               return;
 
-               cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
-               atomic_inc(&nohz.nr_cpus);
-               set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
-       }
-       return;
+       cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
+       atomic_inc(&nohz.nr_cpus);
+       set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
 }
 
 static int __cpuinit sched_ilb_notifier(struct notifier_block *nfb,
@@ -4672,7 +4667,7 @@ static int __cpuinit sched_ilb_notifier(struct notifier_block *nfb,
 {
        switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_DYING:
-               clear_nohz_tick_stopped(smp_processor_id());
+               nohz_balance_exit_idle(smp_processor_id());
                return NOTIFY_OK;
        default:
                return NOTIFY_DONE;
@@ -4833,7 +4828,7 @@ static inline int nohz_kick_needed(struct rq *rq, int cpu)
        * busy tick after returning from idle, we will update the busy stats.
        */
        set_cpu_sd_state_busy();
-       clear_nohz_tick_stopped(cpu);
+       nohz_balance_exit_idle(cpu);
 
        /*
         * None are in tickless mode and hence no need for NOHZ idle load

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3a9e5d5c10916a7e67c131df489617a485a39bfc..1a5ee90eea330e29c91897255f6307e51c153152 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -372,7 +372,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
                 * the scheduler tick in nohz_restart_sched_tick.
                 */
                if (!ts->tick_stopped) {
-                       select_nohz_load_balancer(1);
+                       nohz_balance_enter_idle(cpu);
                        calc_load_enter_idle();
 
                        ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
@@ -569,7 +569,6 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
 static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
 {
        /* Update jiffies first */
-       select_nohz_load_balancer(0);
        tick_do_update_jiffies64(now);
        update_cpu_load_nohz();