sched/fair: Allow calculate_imbalance() to move idle cpus

Allow calculate_imbalance() to 'create' idle cpus in the busiest group
if there are idle cpus in the local group.

Suggested-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140729152705.GX12054@laptop.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2014-07-29 17:15:11 +02:00 коммит произвёл Ingo Molnar
Родитель caeb178c60
Коммит 9a5d9ba6a3
1 изменённых файлов: 5 добавлений и 6 удалений

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@ -6273,12 +6273,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
return fix_small_imbalance(env, sds);
}
if (busiest->group_type == group_overloaded) {
/*
* Don't want to pull so many tasks that a group would go idle.
* Except of course for the group_imb case, since then we might
* have to drop below capacity to reach cpu-load equilibrium.
*/
/*
* If there aren't any idle cpus, avoid creating some.
*/
if (busiest->group_type == group_overloaded &&
local->group_type == group_overloaded) {
load_above_capacity =
(busiest->sum_nr_running - busiest->group_capacity_factor);