From: Vincent Guittot vincent.guittot@linaro.org
[ Upstream commit 91dcf1e8068e9a8823e419a7a34ff4341275fb70 ]
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+GDwwuKZ... Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/sched/fair.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 024d18d85526d..7ac00dede846c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9647,6 +9647,16 @@ 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; + } + }
/*