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-rw-r--r--kernel/sched_fair.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 032b548be0fc..f1c615ff39d6 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -2554,9 +2554,14 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
/*
* In case the child domain prefers tasks go to siblings
* first, lower the sg capacity to one so that we'll try
- * and move all the excess tasks away.
+ * and move all the excess tasks away. We lower the capacity
+ * of a group only if the local group has the capacity to fit
+ * these excess tasks, i.e. nr_running < group_capacity. The
+ * extra check prevents the case where you always pull from the
+ * heaviest group when it is already under-utilized (possible
+ * with a large weight task outweighs the tasks on the system).
*/
- if (prefer_sibling)
+ if (prefer_sibling && !local_group && sds->this_has_capacity)
sgs.group_capacity = min(sgs.group_capacity, 1UL);
if (local_group) {