From 49a456fa8101005d4d22c8ce4e57e65cee438586 Mon Sep 17 00:00:00 2001
From: Divyesh Shah <dpshah@google.com>
Date: Wed, 6 Jan 2010 18:58:20 -0800
Subject: [PATCH] --- yaml --- r: 179685 b: refs/heads/master c:
 875feb63b9567442be73efbcc9a8470e376d6423 h: refs/heads/master i:   179683:
 b48386abcf5fdee4603ee2b26321fa232f16f81d v: v3

---
 [refs]                    | 2 +-
 trunk/block/cfq-iosched.c | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index c2013e5203b4..592185f41cab 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7af92f8754b87bc78cbfd447d5f4096b25c46682
+refs/heads/master: 875feb63b9567442be73efbcc9a8470e376d6423
diff --git a/trunk/block/cfq-iosched.c b/trunk/block/cfq-iosched.c
index 918c7fd9aeb1..ee130f14d1fc 100644
--- a/trunk/block/cfq-iosched.c
+++ b/trunk/block/cfq-iosched.c
@@ -3076,6 +3076,12 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (cfq_class_idle(cfqq))
 		return true;
 
+	/*
+	 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
+	 */
+	if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq))
+		return false;
+
 	/*
 	 * if the new request is sync, but the currently running queue is
 	 * not, let the sync request have priority.