From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jens Axboe <jens.axboe@oracle.com>
Subject: Re: [RFC] page-writeback: move indoes from one superblock together
Date: Thu, 24 Sep 2009 15:17:39 +0200
Message-ID: <20090924131738.GG23126@kernel.dk>
References: <1253775260.10618.10.camel@sli10-desk.sh.intel.com> <20090924071415.GA20808@localhost> <20090924074431.GA22396@sli10-desk.sh.intel.com>
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Cc: "Wu, Fengguang" <fengguang.wu@intel.com>,
	lkml <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Andrew Morton <akpm@linux-foundation.org>,
	Chris Mason <chris.mason@oracle.com>, Jan Kara <jack@suse.cz>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
To: Shaohua Li <shaohua.li@intel.com>
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> > Could just reuse inode.
> oops, forgot to remove it when moveing inode to global.

This is the one I merged. I added the below as wel, we don't need to
reiterate the list if we only moved inodes from a single super block.

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index b27406d..225c731 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -336,17 +336,27 @@ static void move_expired_inodes(struct list_head *delaying_queue,
 {
 	LIST_HEAD(tmp);
 	struct list_head *pos, *node;
-	struct super_block *sb;
+	struct super_block *sb = NULL;
 	struct inode *inode;
+	int do_sb_sort = 0;
 
 	while (!list_empty(delaying_queue)) {
 		inode = list_entry(delaying_queue->prev, struct inode, i_list);
 		if (older_than_this &&
 		    inode_dirtied_after(inode, *older_than_this))
 			break;
+		if (sb && sb != inode->i_sb)
+			do_sb_sort = 1;
+		sb = inode->i_sb;
 		list_move(&inode->i_list, &tmp);
 	}
 
+	/* just one sb in list, splice to dispatch_queue and we're done */
+	if (!do_sb_sort) {
+		list_splice(&tmp, dispatch_queue);
+		return;
+	}
+
 	/* Move inodes from one superblock together */
 	while (!list_empty(&tmp)) {
 		inode = list_entry(tmp.prev, struct inode, i_list);

-- 
Jens Axboe