[tip:sched/core] sched: using dst_rq instead of this_rq during load balance

[tip-bot for Michael Wang <wangyun@linux.vnet.ibm.com>]

Commit-ID:  79a7810be652f95e52325ceadc380f461545ae74
Gitweb:     http://git.kernel.org/tip/79a7810be652f95e52325ceadc380f461545ae74
Author:     Michael Wang <wangyun@linux.vnet.ibm.com>
AuthorDate: Mon, 6 Aug 2012 16:41:59 +0800
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 13 Aug 2012 18:51:59 +0200

sched: using dst_rq instead of this_rq during load balance

As we already have dst_rq in lb_env, using or changing "this_rq" do not
make sense.

This patch will replace "this_rq" with dst_rq in load_balance, and we
don't need to change "this_rq" while process LBF_SOME_PINNED any more.

Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/501F8357.3070102@linux.vnet.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/sched/fair.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 67ac0b1..4f7fcd6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4275,7 +4275,7 @@ redo:
 		goto out_balanced;
 	}
 
-	BUG_ON(busiest == this_rq);
+	BUG_ON(busiest == env.dst_rq);
 
 	schedstat_add(sd, lb_imbalance[idle], env.imbalance);
 
@@ -4295,7 +4295,7 @@ redo:
 
 more_balance:
 		local_irq_save(flags);
-		double_rq_lock(this_rq, busiest);
+		double_rq_lock(env.rq, busiest);
 		if (!env.loop)
 			update_h_load(env.src_cpu);
 
@@ -4305,7 +4305,7 @@ more_balance:
 		 */
 		cur_ld_moved = move_tasks(&env);
 		ld_moved += cur_ld_moved;
-		double_rq_unlock(this_rq, busiest);
+		double_rq_unlock(env.dst_rq, busiest);
 		local_irq_restore(flags);
 
 		if (env.flags & LBF_NEED_BREAK) {
@@ -4341,8 +4341,7 @@ more_balance:
 		if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0 &&
 				lb_iterations++ < max_lb_iterations) {
 
-			this_rq		 = cpu_rq(env.new_dst_cpu);
-			env.dst_rq	 = this_rq;
+			env.dst_rq	 = cpu_rq(env.new_dst_cpu);
 			env.dst_cpu	 = env.new_dst_cpu;
 			env.flags	&= ~LBF_SOME_PINNED;
 			env.loop	 = 0;