sched/fair: Push down check for high priority class task into idle_balance()

We close idle_exit_fair() bracket in case of we've pulled something or we've received
task of high priority class.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: http://lkml.kernel.org/r/1394098315.19290.10.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d8482e1..b956e70 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4787,17 +4787,16 @@ simple:
        return p;
 
 idle:
+       new_tasks = idle_balance(rq);
        /*
         * Because idle_balance() releases (and re-acquires) rq->lock, it is
         * possible for any higher priority task to appear. In that case we
         * must re-start the pick_next_entity() loop.
         */
-       new_tasks = idle_balance(rq);
-
-       if (rq->nr_running != rq->cfs.h_nr_running)
+       if (new_tasks < 0)
                return RETRY_TASK;
 
-       if (new_tasks)
+       if (new_tasks > 0)
                goto again;
 
        return NULL;
@@ -6728,8 +6727,14 @@ static int idle_balance(struct rq *this_rq)
                this_rq->max_idle_balance_cost = curr_cost;
 
 out:
-       if (pulled_task)
+       /* Is there a task of a high priority class? */
+       if (this_rq->nr_running != this_rq->cfs.h_nr_running)
+               pulled_task = -1;
+
+       if (pulled_task) {
+               idle_exit_fair(this_rq);
                this_rq->idle_stamp = 0;
+       }
 
        return pulled_task;
 }

diff --git a/kernel/sched/idle_task.c b/kernel/sched/idle_task.c
index 1f37258..879f2b7 100644 (file)
--- a/kernel/sched/idle_task.c
+++ b/kernel/sched/idle_task.c
@@ -29,7 +29,6 @@ pick_next_task_idle(struct rq *rq, struct task_struct *prev)
        put_prev_task(rq, prev);
 
        schedstat_inc(rq, sched_goidle);
-       idle_enter_fair(rq);
        return rq->idle;
 }