Merge tag 'sched-urgent-2021-07-11' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1b15a19..44c4520 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3256,6 +3256,31 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags)
 
 #ifdef CONFIG_SMP
 #ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * Because list_add_leaf_cfs_rq always places a child cfs_rq on the list
+ * immediately before a parent cfs_rq, and cfs_rqs are removed from the list
+ * bottom-up, we only have to test whether the cfs_rq before us on the list
+ * is our child.
+ * If cfs_rq is not on the list, test whether a child needs its to be added to
+ * connect a branch to the tree  * (see list_add_leaf_cfs_rq() for details).
+ */
+static inline bool child_cfs_rq_on_list(struct cfs_rq *cfs_rq)
+{
+       struct cfs_rq *prev_cfs_rq;
+       struct list_head *prev;
+
+       if (cfs_rq->on_list) {
+               prev = cfs_rq->leaf_cfs_rq_list.prev;
+       } else {
+               struct rq *rq = rq_of(cfs_rq);
+
+               prev = rq->tmp_alone_branch;
+       }
+
+       prev_cfs_rq = container_of(prev, struct cfs_rq, leaf_cfs_rq_list);
+
+       return (prev_cfs_rq->tg->parent == cfs_rq->tg);
+}
 
 static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
 {
@@ -3271,6 +3296,9 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
        if (cfs_rq->avg.runnable_sum)
                return false;
 
+       if (child_cfs_rq_on_list(cfs_rq))
+               return false;
+
        /*
         * _avg must be null when _sum are null because _avg = _sum / divider
         * Make sure that rounding and/or propagation of PELT values never