Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Two load-balancing fixes for cgroups-intense workloads"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix calc_cfs_shares() fixed point arithmetics width confusion
  sched/fair: Fix effective_load() to consistently use smoothed load

1 files changed, 20 insertions, 22 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bdcbeea90c95..c8c5d2d48424 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -735,8 +735,6 @@ void post_init_entity_util_avg(struct sched_entity *se)
         }
 }
 
-static inline unsigned long cfs_rq_runnable_load_avg(struct cfs_rq *cfs_rq);
-static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq);
 #else
 void init_entity_runnable_average(struct sched_entity *se)
 {
@@ -2499,28 +2497,22 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 # ifdef CONFIG_SMP
-static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq)
+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
 {
-        long tg_weight;
+        long tg_weight, load, shares;
 
         /*
-         * Use this CPU's real-time load instead of the last load contribution
-         * as the updating of the contribution is delayed, and we will use the
-         * the real-time load to calc the share. See update_tg_load_avg().
+         * This really should be: cfs_rq->avg.load_avg, but instead we use
+         * cfs_rq->load.weight, which is its upper bound. This helps ramp up
+         * the shares for small weight interactive tasks.
          */
-        tg_weight = atomic_long_read(&tg->load_avg);
-        tg_weight -= cfs_rq->tg_load_avg_contrib;
-        tg_weight += cfs_rq->load.weight;
+        load = scale_load_down(cfs_rq->load.weight);
 
-        return tg_weight;
-}
-
-static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
-{
-        long tg_weight, load, shares;
+        tg_weight = atomic_long_read(&tg->load_avg);
 
-        tg_weight = calc_tg_weight(tg, cfs_rq);
-        load = cfs_rq->load.weight;
+        /* Ensure tg_weight >= load */
+        tg_weight -= cfs_rq->tg_load_avg_contrib;
+        tg_weight += load;
 
         shares = (tg->shares * load);
         if (tg_weight)
@@ -2539,6 +2531,7 @@ static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
         return tg->shares;
 }
 # endif /* CONFIG_SMP */
+
 static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
                             unsigned long weight)
 {
@@ -4946,19 +4939,24 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
                 return wl;
 
         for_each_sched_entity(se) {
-                long w, W;
+                struct cfs_rq *cfs_rq = se->my_q;
+                long W, w = cfs_rq_load_avg(cfs_rq);
 
-                tg = se->my_q->tg;
+                tg = cfs_rq->tg;
 
                 /*
                  * W = @wg + \Sum rw_j
                  */
-                W = wg + calc_tg_weight(tg, se->my_q);
+                W = wg + atomic_long_read(&tg->load_avg);
+
+                /* Ensure \Sum rw_j >= rw_i */
+                W -= cfs_rq->tg_load_avg_contrib;
+                W += w;
 
                 /*
                  * w = rw_i + @wl
                  */
-                w = cfs_rq_load_avg(se->my_q) + wl;
+                w += wl;
 
                 /*
                  * wl = S * s'_i; see (2)