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-rw-r--r--kernel/sched_fair.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 03496eb..3a88dee 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -2743,7 +2743,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
/*
* Consider the group unbalanced when the imbalance is larger
- * than the average weight of two tasks.
+ * than the average weight of a task.
*
* APZ: with cgroup the avg task weight can vary wildly and
* might not be a suitable number - should we keep a
@@ -2753,7 +2753,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
if (sgs->sum_nr_running)
avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
- if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task && max_nr_running > 1)
+ if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
sgs->group_imb = 1;
sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE);
@@ -3128,6 +3128,14 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
if (!sds.busiest || sds.busiest_nr_running == 0)
goto out_balanced;
+ /*
+ * If the busiest group is imbalanced the below checks don't
+ * work because they assumes all things are equal, which typically
+ * isn't true due to cpus_allowed constraints and the like.
+ */
+ if (sds.group_imb)
+ goto force_balance;
+
/* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity &&
!sds.busiest_has_capacity)