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Commit 9a5d9ba6 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarVincent 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: default avatarIngo Molnar <mingo@kernel.org>
parent caeb178c

kernel/sched/fair.c

+5 −6
Original line number Diff line number Diff line
@@ -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);