[PATCH 1/4] sched: Move manipulations with nr_iowait counter to separate functions

[Kirill Tkhai]

Move the (repeating) code to new helpers to reduce its volume and
to improve its readability.

Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
---
 kernel/sched/core.c |   36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 72d1ab9550c0..712ee54edaa1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -794,6 +794,18 @@ void deactivate_task(struct rq *rq, struct task_struct *p, 
int flags)
        dequeue_task(rq, p, flags);
 }
 
+static void task_iowait_start(struct rq *rq, struct task_struct *p)
+{
+       atomic_inc(&rq->nr_iowait);
+       delayacct_blkio_start();
+}
+
+static void task_iowait_end(struct rq *rq, struct task_struct *p)
+{
+       delayacct_blkio_end();
+       atomic_dec(&rq->nr_iowait);
+}
+
 /*
  * __normal_prio - return the priority that is based on the static prio
  */
@@ -2051,10 +2063,8 @@ try_to_wake_up(struct task_struct *p, unsigned int 
state, int wake_flags)
        p->sched_contributes_to_load = !!task_contributes_to_load(p);
        p->state = TASK_WAKING;
 
-       if (p->in_iowait) {
-               delayacct_blkio_end();
-               atomic_dec(&task_rq(p)->nr_iowait);
-       }
+       if (p->in_iowait)
+               task_iowait_end(task_rq(p), p);
 
        cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
        if (task_cpu(p) != cpu) {
@@ -2064,10 +2074,8 @@ try_to_wake_up(struct task_struct *p, unsigned int 
state, int wake_flags)
 
 #else /* CONFIG_SMP */
 
-       if (p->in_iowait) {
-               delayacct_blkio_end();
-               atomic_dec(&task_rq(p)->nr_iowait);
-       }
+       if (p->in_iowait)
+               task_iowait_end(task_rq(p), p);
 
 #endif /* CONFIG_SMP */
 
@@ -2117,10 +2125,8 @@ static void try_to_wake_up_local(struct task_struct *p, 
struct rq_flags *rf)
        trace_sched_waking(p);
 
        if (!task_on_rq_queued(p)) {
-               if (p->in_iowait) {
-                       delayacct_blkio_end();
-                       atomic_dec(&rq->nr_iowait);
-               }
+               if (p->in_iowait)
+                       task_iowait_end(rq, p);
                ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK);
        }
 
@@ -3320,10 +3326,8 @@ static void __sched notrace __schedule(bool preempt)
                        deactivate_task(rq, prev, DEQUEUE_SLEEP | 
DEQUEUE_NOCLOCK);
                        prev->on_rq = 0;
 
-                       if (prev->in_iowait) {
-                               atomic_inc(&rq->nr_iowait);
-                               delayacct_blkio_start();
-                       }
+                       if (prev->in_iowait)
+                               task_iowait_start(rq, prev);
 
                        /*
                         * If a worker went to sleep, notify and ask workqueue