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Subject[PATCH 2/3] sched/fair: don't set LBF_ALL_PINNED unnecessarily
Date
Setting LBF_ALL_PINNED during active load balance is only valid when there
is only 1 running task on the rq otherwise this ends up increasing the
balance interval whereas other tasks could migrate after the next interval
once they become cache-cold as an example.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/fair.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5428b8723e61..69a455113b10 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9759,7 +9759,8 @@ static int load_balance(int this_cpu, struct rq *this_rq,
if (!cpumask_test_cpu(this_cpu, busiest->curr->cpus_ptr)) {
raw_spin_unlock_irqrestore(&busiest->lock,
flags);
- env.flags |= LBF_ALL_PINNED;
+ if (busiest->nr_running == 1)
+ env.flags |= LBF_ALL_PINNED;
goto out_one_pinned;
}

--
2.17.1
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