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Commit e4188507 authored by Morten Rasmussen's avatar Morten Rasmussen Committed by Andres Oportus
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ANDROID: sched/fair: Fix sched_group_energy() to support per-cpu capacity states 



sched_group_energy() was supposed to support per-cpu capacity states
(DVFS), however, while fixing a hotplug issue this was broken as we bail
out if there is no SD_SHARE_CAP_STATES flag set.

This patch implements the hotplug race check differently and should
therefore reinstate support for per-cpu capacity states.

Change-Id: I5b865666c9ce833dcfa6514c574580d75aa0a195
Signed-off-by: default avatarMorten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: default avatarQuentin Perret <quentin.perret@arm.com>
parent 352e0961

kernel/sched/fair.c

+9 −9
Original line number Diff line number Diff line
@@ -5582,15 +5582,7 @@ static int sched_group_energy(struct energy_env *eenv) 
		 */

		sd = rcu_dereference(per_cpu(sd_scs, cpu));



		if (!sd)

			/*

			 * We most probably raced with hotplug; returning a

			 * wrong energy estimation is better than entering an

			 * infinite loop.

			 */

			return -EINVAL;



		if (sd->parent)

		if (sd && sd->parent)

			sg_shared_cap = sd->parent->groups;



		for_each_domain(cpu, sd) {
@@ -5645,6 +5637,14 @@ static int sched_group_energy(struct energy_env *eenv) 


			} while (sg = sg->next, sg != sd->groups);

		}



		/*

		 * If we raced with hotplug and got an sd NULL-pointer;

		 * returning a wrong energy estimation is better than

		 * entering an infinite loop.

		 */

		if (cpumask_test_cpu(cpu, &visit_cpus))

			return -EINVAL;

next_cpu:

		cpumask_clear_cpu(cpu, &visit_cpus);

		continue;