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authorVincent Guittot <vincent.guittot@linaro.org>2023-04-11 11:06:11 +0200
committerPeter Zijlstra <peterz@infradead.org>2023-04-12 16:46:30 +0200
commit91dcf1e8068e9a8823e419a7a34ff4341275fb70 (patch)
treeef17c6282989ffebc78319863054b07d189fd18a
parent09a9639e56c01c7a00d6c0ca63f4c7c41abe075d (diff)
downloadlinux-91dcf1e8068e9a8823e419a7a34ff4341275fb70.tar.gz
sched/fair: Fix imbalance overflow
When local group is fully busy but its average load is above system load, computing the imbalance will overflow and local group is not the best target for pulling this load. Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()") Reported-by: Tingjia Cao <tjcao980311@gmail.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Tingjia Cao <tjcao980311@gmail.com> Link: https://lore.kernel.org/lkml/CABcWv9_DAhVBOq2=W=2ypKE9dKM5s2DvoV8-U0+GDwwuKZ89jQ@mail.gmail.com/T/
-rw-r--r--kernel/sched/fair.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6986ea31c9844..5f6587d94c1dd 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10238,6 +10238,16 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
sds->avg_load = (sds->total_load * SCHED_CAPACITY_SCALE) /
sds->total_capacity;
+
+ /*
+ * If the local group is more loaded than the average system
+ * load, don't try to pull any tasks.
+ */
+ if (local->avg_load >= sds->avg_load) {
+ env->imbalance = 0;
+ return;
+ }
+
}
/*