mac80211: move averaged values out of rx_stats

[cascardo/linux.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 46d64e4..0fe30e6 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3181,17 +3181,25 @@ static inline void check_schedstat_required(void)
 static void
 enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
 {
+       bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING);
+       bool curr = cfs_rq->curr == se;
+
        /*
-        * Update the normalized vruntime before updating min_vruntime
-        * through calling update_curr().
+        * If we're the current task, we must renormalise before calling
+        * update_curr().
         */
-       if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
+       if (renorm && curr)
                se->vruntime += cfs_rq->min_vruntime;
 
+       update_curr(cfs_rq);
+
        /*
-        * Update run-time statistics of the 'current'.
+        * Otherwise, renormalise after, such that we're placed at the current
+        * moment in time, instead of some random moment in the past.
         */
-       update_curr(cfs_rq);
+       if (renorm && !curr)
+               se->vruntime += cfs_rq->min_vruntime;
+
        enqueue_entity_load_avg(cfs_rq, se);
        account_entity_enqueue(cfs_rq, se);
        update_cfs_shares(cfs_rq);
@@ -3207,7 +3215,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
                update_stats_enqueue(cfs_rq, se);
                check_spread(cfs_rq, se);
        }
-       if (se != cfs_rq->curr)
+       if (!curr)
                __enqueue_entity(cfs_rq, se);
        se->on_rq = 1;
 
@@ -5071,7 +5079,19 @@ static int select_idle_sibling(struct task_struct *p, int target)
                return i;
 
        /*
-        * Otherwise, iterate the domains and find an elegible idle cpu.
+        * Otherwise, iterate the domains and find an eligible idle cpu.
+        *
+        * A completely idle sched group at higher domains is more
+        * desirable than an idle group at a lower level, because lower
+        * domains have smaller groups and usually share hardware
+        * resources which causes tasks to contend on them, e.g. x86
+        * hyperthread siblings in the lowest domain (SMT) can contend
+        * on the shared cpu pipeline.
+        *
+        * However, while we prefer idle groups at higher domains
+        * finding an idle cpu at the lowest domain is still better than
+        * returning 'target', which we've already established, isn't
+        * idle.
         */
        sd = rcu_dereference(per_cpu(sd_llc, target));
        for_each_lower_domain(sd) {
@@ -5081,11 +5101,16 @@ static int select_idle_sibling(struct task_struct *p, int target)
                                                tsk_cpus_allowed(p)))
                                goto next;
 
+                       /* Ensure the entire group is idle */
                        for_each_cpu(i, sched_group_cpus(sg)) {
                                if (i == target || !idle_cpu(i))
                                        goto next;
                        }
 
+                       /*
+                        * It doesn't matter which cpu we pick, the
+                        * whole group is idle.
+                        */
                        target = cpumask_first_and(sched_group_cpus(sg),
                                        tsk_cpus_allowed(p));
                        goto done;