1 files changed, 16 insertions, 10 deletions

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a543a5b202a4..b320753aa6c9 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -146,8 +146,20 @@ static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
 static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
 {
         if (!cfs_rq->on_list) {
-                list_add_rcu(&cfs_rq->leaf_cfs_rq_list,
+                /*
+                 * Ensure we either appear before our parent (if already
+                 * enqueued) or force our parent to appear after us when it is
+                 * enqueued.  The fact that we always enqueue bottom-up
+                 * reduces this to two cases.
+                 */
+                if (cfs_rq->tg->parent &&
+                    cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) {
+                        list_add_rcu(&cfs_rq->leaf_cfs_rq_list,
+                                &rq_of(cfs_rq)->leaf_cfs_rq_list);
+                } else {
+                        list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
                                 &rq_of(cfs_rq)->leaf_cfs_rq_list);
+                }
 
                 cfs_rq->on_list = 1;
         }
@@ -2016,7 +2028,7 @@ out:
 /*
  * update tg->load_weight by folding this cpu's load_avg
  */
-static int tg_shares_up(struct task_group *tg, int cpu)
+static int update_shares_cpu(struct task_group *tg, int cpu)
 {
         struct cfs_rq *cfs_rq;
         unsigned long flags;
@@ -2056,14 +2068,8 @@ static void update_shares(int cpu)
         struct rq *rq = cpu_rq(cpu);
 
         rcu_read_lock();
-        for_each_leaf_cfs_rq(rq, cfs_rq) {
-                struct task_group *tg = cfs_rq->tg;
-
-                do {
-                        tg_shares_up(tg, cpu);
-                        tg = tg->parent;
-                } while (tg);
-        }
+        for_each_leaf_cfs_rq(rq, cfs_rq)
+                update_shares_cpu(cfs_rq->tg, cpu);
         rcu_read_unlock();
 }