From 5c03449d34debca0deab58046377e1175c1bcd7e Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 24 Sep 2009 14:42:33 +0200 Subject: [PATCH] writeback: move inodes from one super_block together __mark_inode_dirty adds inode to wb dirty list in random order. If a disk has several partitions, writeback might keep spindle moving between partitions. To reduce the move, better write big chunk of one partition and then move to another. Inodes from one fs usually are in one partion, so idealy move indoes from one fs together should reduce spindle move. This patch tries to address this. Before per-bdi writeback is added, the behavior is write indoes from one fs first and then another, so the patch restores previous behavior. The loop in the patch is a bit ugly, should we add a dirty list for each superblock in bdi_writeback? Test in a two partition disk with attached fio script shows about 3% ~ 6% improvement. Signed-off-by: Shaohua Li Reviewed-by: Wu Fengguang Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 15944f754e15..b27406d51bc7 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -334,13 +334,28 @@ static void move_expired_inodes(struct list_head *delaying_queue, struct list_head *dispatch_queue, unsigned long *older_than_this) { + LIST_HEAD(tmp); + struct list_head *pos, *node; + struct super_block *sb; + struct inode *inode; + while (!list_empty(delaying_queue)) { - struct inode *inode = list_entry(delaying_queue->prev, - struct inode, i_list); + inode = list_entry(delaying_queue->prev, struct inode, i_list); if (older_than_this && inode_dirtied_after(inode, *older_than_this)) break; - list_move(&inode->i_list, dispatch_queue); + list_move(&inode->i_list, &tmp); + } + + /* Move inodes from one superblock together */ + while (!list_empty(&tmp)) { + inode = list_entry(tmp.prev, struct inode, i_list); + sb = inode->i_sb; + list_for_each_prev_safe(pos, node, &tmp) { + inode = list_entry(pos, struct inode, i_list); + if (inode->i_sb == sb) + list_move(&inode->i_list, dispatch_queue); + } } }