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Commit 56ffdd61 authored by Dietmar Eggemann's avatar Dietmar Eggemann Committed by Andres Oportus
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ANDROID: sched/fair: Simplify idle_idx handling in select_idle_sibling() 



Rename best_idle to best_idle_cpu so the same name is used like in
find_best_target().

Fix if (best_idle > 0) since best_idle_cpu = 0 is a valid target.

Use 'unsigned long' data type for best_idle_capacity.

Since we're looking for the shallowest best_idle_cstate initialize
best_idle_cstate = INT_MAX. For cpus which are not idle (idle_idx = -1)
the condition 'if (idle_idx < best_idle_cstate && ...)' is never
executed.

Change-Id: Ic5b63d58478696b3d1ec6253cf739a69a574cf99
Signed-off-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
(cherry picked from commit 8bff5e9c0968108d465e1f2a4624fc5ec2f00849)
Signed-off-by: default avatarChris Redpath <chris.redpath@arm.com>
Signed-off-by: default avatarQuentin Perret <quentin.perret@arm.com>
parent 2dfb172d

kernel/sched/fair.c

+11 −9
Original line number Diff line number Diff line
@@ -6187,9 +6187,9 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) 
	struct sched_domain *sd;

	struct sched_group *sg;

	int i = task_cpu(p);

	int best_idle = -1;

	int best_idle_cstate = -1;

	int best_idle_capacity = INT_MAX;

	int best_idle_cpu = -1;

	int best_idle_cstate = INT_MAX;

	unsigned long best_idle_capacity = ULONG_MAX;



	if (!sysctl_sched_cstate_aware) {

		if (idle_cpu(target))
@@ -6232,18 +6232,19 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) 


			if (sysctl_sched_cstate_aware) {

				for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg)) {

					struct rq *rq = cpu_rq(i);

					int idle_idx = idle_get_state_idx(rq);

					int idle_idx = idle_get_state_idx(cpu_rq(i));

					unsigned long new_usage = boosted_task_util(p);

					unsigned long capacity_orig = capacity_orig_of(i);



					if (new_usage > capacity_orig || !idle_cpu(i))

						goto next;



					if (i == target && new_usage <= capacity_curr_of(target))

						return target;



					if (best_idle < 0 || (idle_idx < best_idle_cstate && capacity_orig <= best_idle_capacity)) {

						best_idle = i;

					if (idle_idx < best_idle_cstate &&

					    capacity_orig <= best_idle_capacity) {

						best_idle_cpu = i;

						best_idle_cstate = idle_idx;

						best_idle_capacity = capacity_orig;

					}
@@ -6262,8 +6263,9 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) 
			sg = sg->next;

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

	}

	if (best_idle > 0)

		target = best_idle;



	if (best_idle_cpu >= 0)

		target = best_idle_cpu;



done:

	return target;