Since sds->max_load, sds->this_load, scaled_busy_load_per_task are all
unsigned long type, so it make even sds->max_load less than
sds->this_load, the statement as below would still be true.
(sds->max_load - sds->this_load + scaled_busy_load_per_task >=
(scaled_busy_load_per_task * imbn)
This would make load balance happen, even the busiest group's load is
less than local group's load...
Signed-off-by: Lei Wen <lei...@marvell.com>
---
kernel/sched/fair.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c61a614..8d11a69 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4693,6 +4693,7 @@ void fix_small_imbalance(struct lb_env *env, struct
sd_lb_stats *sds)
unsigned long tmp, pwr_now = 0, pwr_move = 0;
unsigned int imbn = 2;
unsigned long scaled_busy_load_per_task;
+ int balance;
if (sds->this_nr_running) {
sds->this_load_per_task /= sds->this_nr_running;
@@ -4708,8 +4709,9 @@ void fix_small_imbalance(struct lb_env *env, struct
sd_lb_stats *sds)
* SCHED_POWER_SCALE;
scaled_busy_load_per_task /= sds->busiest->sgp->power;
- if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
- (scaled_busy_load_per_task * imbn)) {
+ balance = sds->max_load - sds->this_load
+ + scaled_busy_load_per_task * (1 - imbn);
+ if (balance >=0) {
env->imbalance = sds->busiest_load_per_task;
return;
}
--
1.7.10.4
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