From 75a7ab89211bee5a679063d830a9af11ff800b96 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Fri, 17 Dec 2010 20:08:04 +1100
Subject: [PATCH] --- yaml --- r: 229047 b: refs/heads/master c:
 e677d0f9548e2245ee3c2977661ca8ca165af188 h: refs/heads/master i:   229045:
 9efbdc703e17ad5bf55ed59c65d639f9bcd2cb6d   229043:
 35eefe8b37be87924c76330a7b385f69b3a5dbe8   229039:
 09549673a3954e6b32bf4b374d0702cc074ee321 v: v3

---
 [refs]                             |  2 +-
 trunk/fs/xfs/linux-2.6/xfs_super.c | 20 ++++++++++++++++----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index 9a45bcfcea04..d0d23ed0c66a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0e57f6a36f9be03e5abb755f524ee91c4aebe854
+refs/heads/master: e677d0f9548e2245ee3c2977661ca8ca165af188
diff --git a/trunk/fs/xfs/linux-2.6/xfs_super.c b/trunk/fs/xfs/linux-2.6/xfs_super.c
index c45b3233d486..c51faaa5e291 100644
--- a/trunk/fs/xfs/linux-2.6/xfs_super.c
+++ b/trunk/fs/xfs/linux-2.6/xfs_super.c
@@ -834,8 +834,11 @@ xfsaild_wakeup(
 	struct xfs_ail		*ailp,
 	xfs_lsn_t		threshold_lsn)
 {
-	ailp->xa_target = threshold_lsn;
-	wake_up_process(ailp->xa_task);
+	/* only ever move the target forwards */
+	if (XFS_LSN_CMP(threshold_lsn, ailp->xa_target) > 0) {
+		ailp->xa_target = threshold_lsn;
+		wake_up_process(ailp->xa_task);
+	}
 }
 
 STATIC int
@@ -847,8 +850,17 @@ xfsaild(
 	long		tout = 0; /* milliseconds */
 
 	while (!kthread_should_stop()) {
-		schedule_timeout_interruptible(tout ?
-				msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
+		/*
+		 * for short sleeps indicating congestion, don't allow us to
+		 * get woken early. Otherwise all we do is bang on the AIL lock
+		 * without making progress.
+		 */
+		if (tout && tout <= 20)
+			__set_current_state(TASK_KILLABLE);
+		else
+			__set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(tout ?
+				 msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
 
 		/* swsusp */
 		try_to_freeze();