[PATCH] sched/fair: Rearrange select_task_rq_fair() to optimize it

[Viresh Kumar]

Rearrange select_task_rq_fair() a bit to avoid executing some
conditional statements in few specific code-paths. That gets rid of the
goto as well.

This shouldn't result in any functional changes.

Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
 kernel/sched/fair.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 54dc31e7ab9b..cacee15076a4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6636,6 +6636,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, 
int sd_flag, int wake_f
                 */
                if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
                    cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
+                       sd = NULL; /* Prefer wake_affine over balance flags */
                        affine_sd = tmp;
                        break;
                }
@@ -6646,33 +6647,26 @@ select_task_rq_fair(struct task_struct *p, int 
prev_cpu, int sd_flag, int wake_f
                        break;
        }
 
-       if (affine_sd) {
-               sd = NULL; /* Prefer wake_affine over balance flags */
-               if (cpu == prev_cpu)
-                       goto pick_cpu;
-
-               new_cpu = wake_affine(affine_sd, p, cpu, prev_cpu, sync);
-       }
-
-       if (sd && !(sd_flag & SD_BALANCE_FORK)) {
+       if (sd) {
                /*
                 * We're going to need the task's util for capacity_spare_wake
                 * in find_idlest_group. Sync it up to prev_cpu's
                 * last_update_time.
                 */
-               sync_entity_load_avg(&p->se);
-       }
+               if (!(sd_flag & SD_BALANCE_FORK))
+                       sync_entity_load_avg(&p->se);
+
+               new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
+       } else {
+               if (affine_sd && cpu != prev_cpu)
+                       new_cpu = wake_affine(affine_sd, p, cpu, prev_cpu, 
sync);
 
-       if (!sd) {
-pick_cpu:
                if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */
                        new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
 
                        if (want_affine)
                                current->recent_used_cpu = cpu;
                }
-       } else {
-               new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
        }
        rcu_read_unlock();
 
-- 
2.15.0.194.g9af6a3dea062