1 files changed, 72 insertions, 41 deletions

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index c62ebae65cf0..354769979c02 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -699,7 +699,8 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
         cfs_rq->nr_running--;
 }
 
-#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_FAIR_GROUP_SCHED
+# ifdef CONFIG_SMP
 static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
                                             int global_update)
 {
@@ -762,6 +763,51 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
                 list_del_leaf_cfs_rq(cfs_rq);
 }
 
+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+                                long weight_delta)
+{
+        long load_weight, load, shares;
+
+        load = cfs_rq->load.weight + weight_delta;
+
+        load_weight = atomic_read(&tg->load_weight);
+        load_weight -= cfs_rq->load_contribution;
+        load_weight += load;
+
+        shares = (tg->shares * load);
+        if (load_weight)
+                shares /= load_weight;
+
+        if (shares < MIN_SHARES)
+                shares = MIN_SHARES;
+        if (shares > tg->shares)
+                shares = tg->shares;
+
+        return shares;
+}
+
+static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+        if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
+                update_cfs_load(cfs_rq, 0);
+                update_cfs_shares(cfs_rq, 0);
+        }
+}
+# else /* CONFIG_SMP */
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+}
+
+static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+                                long weight_delta)
+{
+        return tg->shares;
+}
+
+static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+}
+# endif /* CONFIG_SMP */
 static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
                             unsigned long weight)
 {
@@ -782,7 +828,7 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
 {
         struct task_group *tg;
         struct sched_entity *se;
-        long load_weight, load, shares;
+        long shares;
 
         if (!cfs_rq)
                 return;
@@ -791,32 +837,14 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
         se = tg->se[cpu_of(rq_of(cfs_rq))];
         if (!se)
                 return;
-
-        load = cfs_rq->load.weight + weight_delta;
-
-        load_weight = atomic_read(&tg->load_weight);
-        load_weight -= cfs_rq->load_contribution;
-        load_weight += load;
-
-        shares = (tg->shares * load);
-        if (load_weight)
-                shares /= load_weight;
-
-        if (shares < MIN_SHARES)
-                shares = MIN_SHARES;
-        if (shares > tg->shares)
-                shares = tg->shares;
+#ifndef CONFIG_SMP
+        if (likely(se->load.weight == tg->shares))
+                return;
+#endif
+        shares = calc_cfs_shares(cfs_rq, tg, weight_delta);
 
         reweight_entity(cfs_rq_of(se), se, shares);
 }
-
-static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
-        if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
-                update_cfs_load(cfs_rq, 0);
-                update_cfs_shares(cfs_rq, 0);
-        }
-}
 #else /* CONFIG_FAIR_GROUP_SCHED */
 static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 {
@@ -1062,6 +1090,9 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
                 struct sched_entity *se = __pick_next_entity(cfs_rq);
                 s64 delta = curr->vruntime - se->vruntime;
 
+                if (delta < 0)
+                        return;
+
                 if (delta > ideal_runtime)
                         resched_task(rq_of(cfs_rq)->curr);
         }
@@ -1362,27 +1393,27 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
                 return wl;
 
         for_each_sched_entity(se) {
-                long S, rw, s, a, b;
+                long lw, w;
 
-                S = se->my_q->tg->shares;
-                s = se->load.weight;
-                rw = se->my_q->load.weight;
+                tg = se->my_q->tg;
+                w = se->my_q->load.weight;
 
-                a = S*(rw + wl);
-                b = S*rw + s*wg;
+                /* use this cpu's instantaneous contribution */
+                lw = atomic_read(&tg->load_weight);
+                lw -= se->my_q->load_contribution;
+                lw += w + wg;
 
-                wl = s*(a-b);
+                wl += w;
 
-                if (likely(b))
-                        wl /= b;
+                if (lw > 0 && wl < lw)
+                        wl = (wl * tg->shares) / lw;
+                else
+                        wl = tg->shares;
 
-                /*
-                 * Assume the group is already running and will
-                 * thus already be accounted for in the weight.
-                 *
-                 * That is, moving shares between CPUs, does not
-                 * alter the group weight.
-                 */
+                /* zero point is MIN_SHARES */
+                if (wl < MIN_SHARES)
+                        wl = MIN_SHARES;
+                wl -= se->load.weight;
                 wg = 0;
         }