[PATCH] sched: move idle status calculation into rebalance_tick()

Perform the idle state determination in rebalance_tick.

If we separate balancing from sched_tick then we also need to determine the
idle state in rebalance_tick.

V2->V3
	Remove useless idlle != 0 check. Checking nr_running seems
	to be sufficient. Thanks Suresh.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Peter Williams <pwil3058@bigpond.net.au>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/sched.c b/kernel/sched.c
index 3c1b74aa1b07ae32227a3fabaae847e6023308c1..14a8d9050cd431c6420769e712d71468445c653b 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2867,10 +2867,16 @@ static void update_load(struct rq *this_rq)
  */
 
 static void
-rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
+rebalance_tick(int this_cpu, struct rq *this_rq)
 {
        unsigned long interval;
        struct sched_domain *sd;
+       /*
+        * We are idle if there are no processes running. This
+        * is valid even if we are the idle process (SMT).
+        */
+       enum idle_type idle = !this_rq->nr_running ?
+                               SCHED_IDLE : NOT_IDLE;
 
        for_each_domain(this_cpu, sd) {
                if (!(sd->flags & SD_LOAD_BALANCE))
@@ -2902,37 +2908,26 @@ rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
 /*
  * on UP we do not need to balance between CPUs:
  */
-static inline void rebalance_tick(int cpu, struct rq *rq)
-{
-}
 static inline void idle_balance(int cpu, struct rq *rq)
 {
 }
-static inline void update_load(struct rq *this_rq)
-{
-}
 #endif
 
-static inline int wake_priority_sleeper(struct rq *rq)
+static inline void wake_priority_sleeper(struct rq *rq)
 {
-       int ret = 0;
-
 #ifdef CONFIG_SCHED_SMT
        if (!rq->nr_running)
-               return 0;
+               return;
 
        spin_lock(&rq->lock);
        /*
         * If an SMT sibling task has been put to sleep for priority
         * reasons reschedule the idle task to see if it can now run.
         */
-       if (rq->nr_running) {
+       if (rq->nr_running)
                resched_task(rq->idle);
-               ret = 1;
-       }
        spin_unlock(&rq->lock);
 #endif
-       return ret;
 }
 
 DEFINE_PER_CPU(struct kernel_stat, kstat);
@@ -3148,20 +3143,20 @@ void scheduler_tick(void)
        struct task_struct *p = current;
        int cpu = smp_processor_id();
        struct rq *rq = cpu_rq(cpu);
-       enum idle_type idle = NOT_IDLE;
 
        update_cpu_clock(p, rq, now);
 
        rq->timestamp_last_tick = now;
 
-       if (p == rq->idle) {
+       if (p == rq->idle)
                /* Task on the idle queue */
-               if (!wake_priority_sleeper(rq))
-                       idle = SCHED_IDLE;
-       } else
+               wake_priority_sleeper(rq);
+       else
                task_running_tick(rq, p);
+#ifdef CONFIG_SMP
        update_load(rq);
-       rebalance_tick(cpu, rq, idle);
+       rebalance_tick(cpu, rq);
+#endif
 }
 
 #ifdef CONFIG_SCHED_SMT