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Commit 5383285d authored by Ionela Voinescu's avatar Ionela Voinescu
Browse files

ANDROID: sched/fair: unify spare capacity calculation 



Given that we have a few sites where the spare capacity of a CPU is
calculated as the difference between the original capacity of the CPU
and its computed new utilization, let's unify the calculation and use
that value tracked with a local spare_cap variable.

Change-Id: I78daece7543f78d4f74edbee5e9ceb62908af507
Signed-off-by: default avatarIonela Voinescu <ionela.voinescu@arm.com>
parent 03429a53

kernel/sched/fair.c

+13 −5
Original line number Diff line number Diff line
@@ -6941,6 +6941,7 @@ static inline int find_best_target(struct task_struct *p, int *backup_cpu, 
			unsigned long capacity_curr = capacity_curr_of(i);

			unsigned long capacity_orig = capacity_orig_of(i);

			unsigned long wake_util, new_util;

			long spare_cap;



			if (!cpu_online(i))

				continue;
@@ -6965,6 +6966,13 @@ static inline int find_best_target(struct task_struct *p, int *backup_cpu, 
			if (new_util > capacity_orig)

				continue;



			/*

			 * Pre-compute the maximum possible capacity we expect

			 * to have available on this CPU once the task is

			 * enqueued here.

			 */

			spare_cap = capacity_orig - new_util;



			/*

			 * Case A) Latency sensitive tasks

			 *
@@ -7012,9 +7020,9 @@ static inline int find_best_target(struct task_struct *p, int *backup_cpu, 
				 * Case A.2: Target ACTIVE CPU

				 * Favor CPUs with max spare capacity.

				 */

				if ((capacity_curr > new_util) &&

					(capacity_orig - new_util > target_max_spare_cap)) {

					target_max_spare_cap = capacity_orig - new_util;

				if (capacity_curr > new_util &&

				    spare_cap > target_max_spare_cap) {

					target_max_spare_cap = spare_cap;

					target_cpu = i;

					continue;

				}
@@ -7124,10 +7132,10 @@ static inline int find_best_target(struct task_struct *p, int *backup_cpu, 


			/* Favor CPUs with maximum spare capacity */

			if (capacity_orig == target_capacity &&

			    (capacity_orig - new_util) < target_max_spare_cap)

			    spare_cap < target_max_spare_cap)

				continue;



			target_max_spare_cap = capacity_orig - new_util;

			target_max_spare_cap = spare_cap;

			target_capacity = capacity_orig;

			target_util = new_util;

			target_cpu = i;