[PATCH v3 8/8] cfq: Don't allow preemption across cgroups

[Justin TerAvest <teravest@google.com>]

Previously, a sync queue in can preempt an async queue in another
cgroup. This changes that behavior to disallow such preemption.

Signed-off-by: Justin TerAvest <teravest@google.com>
---
 block/cfq-iosched.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 23caa79..0d0189b 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3430,6 +3430,9 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (!cfqq)
 		return false;
 
+	if (new_cfqq->cfqg != cfqq->cfqg)
+		return false;
+
 	if (cfq_class_idle(new_cfqq))
 		return false;
 
@@ -3449,9 +3452,6 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
 		return true;
 
-	if (new_cfqq->cfqg != cfqq->cfqg)
-		return false;
-
 	if (cfq_slice_used(cfqq))
 		return true;
 
-- 
1.7.3.1