[PATCH 11/30] sched: kill task_group balancing

[Peter Zijlstra]

From: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>

The idea was to balance groups until we've reached the global goal, however
Vatsa rightly pointed out that we might never reach that goal this way -
hence take out this logic.

[ the initial rationale for this 'feature' was to promote max concurrency
  within a group - it does not however affect fairness ]

Reported-by: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
 kernel/sched_fair.c |   15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

Index: linux-2.6/kernel/sched_fair.c
===================================================================
--- linux-2.6.orig/kernel/sched_fair.c
+++ linux-2.6/kernel/sched_fair.c
@@ -1427,9 +1427,7 @@ load_balance_fair(struct rq *this_rq, in
 
 	rcu_read_lock();
 	list_for_each_entry(tg, &task_groups, list) {
-		long imbalance;
-		unsigned long this_weight, busiest_weight;
-		long rem_load, max_load, moved_load;
+		long rem_load, moved_load;
 
 		/*
 		 * empty group
@@ -1440,17 +1438,8 @@ load_balance_fair(struct rq *this_rq, in
 		rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight;
 		rem_load /= aggregate(tg, this_cpu)->load + 1;
 
-		this_weight = tg->cfs_rq[this_cpu]->task_weight;
-		busiest_weight = tg->cfs_rq[busiest_cpu]->task_weight;
-
-		imbalance = (busiest_weight - this_weight) / 2;
-
-		if (imbalance < 0)
-			imbalance = busiest_weight;
-
-		max_load = max(rem_load, imbalance);
 		moved_load = __load_balance_fair(this_rq, this_cpu, busiest,
-				max_load, sd, idle, all_pinned, this_best_prio,
+				rem_load, sd, idle, all_pinned, this_best_prio,
 				tg->cfs_rq[busiest_cpu]);
 
 		if (!moved_load)

-- 

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