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Commit cc57aa8f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Clean up some f_b_g() comments 



The existing comment tends to grow state (as it already has), split it
up and place it near the actual tests.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nikhil Rao <ncrao@google.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c186fafe

kernel/sched_fair.c

+13 −15
Original line number Diff line number Diff line
@@ -3113,19 +3113,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
	 */

	update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds);



	/* Cases where imbalance does not exist from POV of this_cpu */

	/* 1) this_cpu is not the appropriate cpu to perform load balancing

	 *    at this level.

	 * 2) There is no busy sibling group to pull from.

	 * 3) This group is the busiest group.

	 * 4) This group is more busy than the avg busieness at this

	 *    sched_domain.

	 * 5) The imbalance is within the specified limit.

	 *

	 * Note: when doing newidle balance, if the local group has excess

	 * capacity (i.e. nr_running < group_capacity) and the busiest group

	 * does not have any capacity, we force a load balance to pull tasks

	 * to the local group. In this case, we skip past checks 3, 4 and 5.

	/*

	 * this_cpu is not the appropriate cpu to perform load balancing at

	 * this level.

	 */

	if (!(*balance))

		goto ret;
@@ -3134,6 +3124,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
	    check_asym_packing(sd, &sds, this_cpu, imbalance))

		return sds.busiest;



	/* There is no busy sibling group to pull tasks from */

	if (!sds.busiest || sds.busiest_nr_running == 0)

		goto out_balanced;
@@ -3142,11 +3133,18 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, 
			!sds.busiest_has_capacity)

		goto force_balance;



	/*

	 * If the local group is more busy than the selected busiest group

	 * don't try and pull any tasks.

	 */

	if (sds.this_load >= sds.max_load)

		goto out_balanced;



	/*

	 * Don't pull any tasks if this group is already above the domain

	 * average load.

	 */

	sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;



	if (sds.this_load >= sds.avg_load)

		goto out_balanced;