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Commit 0c117f1b authored by Siddha, Suresh B's avatar Siddha, Suresh B Committed by Linus Torvalds
Browse files

[PATCH] sched: allow the load to grow upto its cpu_power 



Don't pull tasks from a group if that would cause the group's total load to
drop below its total cpu_power (ie.  cause the group to start going idle).

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fa3b6ddc

kernel/sched.c

+7 −2
Original line number Diff line number Diff line
@@ -1910,6 +1910,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
{

	struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;

	unsigned long max_load, avg_load, total_load, this_load, total_pwr;

	unsigned long max_pull;

	int load_idx;



	max_load = this_load = total_load = total_pwr = 0;
@@ -1959,7 +1960,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
		group = group->next;

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



	if (!busiest || this_load >= max_load)

	if (!busiest || this_load >= max_load || max_load <= SCHED_LOAD_SCALE)

		goto out_balanced;



	avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
@@ -1979,8 +1980,12 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
	 * by pulling tasks to us.  Be careful of negative numbers as they'll

	 * appear as very large values with unsigned longs.

	 */



	/* Don't want to pull so many tasks that a group would go idle */

	max_pull = min(max_load - avg_load, max_load - SCHED_LOAD_SCALE);



	/* How much load to actually move to equalise the imbalance */

	*imbalance = min((max_load - avg_load) * busiest->cpu_power,

	*imbalance = min(max_pull * busiest->cpu_power,

				(avg_load - this_load) * this->cpu_power)

			/ SCHED_LOAD_SCALE;