From a8855990e382fc81c04187c5fdb48743307baf32 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 9 Jul 2013 22:36:45 +0800 Subject: writeback: Do not sort b_io list only because of block device inode It is very likely that block device inode will be part of BDI dirty list as well. However it doesn't make sence to sort inodes on the b_io list just because of this inode (as it contains buffers all over the device anyway). So save some CPU cycles which is valuable since we hold relatively contented wb->list_lock. Signed-off-by: Jan Kara --- fs/block_dev.c | 2 +- fs/fs-writeback.c | 8 +++++--- include/linux/fs.h | 6 ++++++ 3 files changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index 2091db8cdd78..256233098206 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -606,7 +606,7 @@ static struct block_device *bd_acquire(struct inode *inode) return bdev; } -static inline int sb_is_blkdev_sb(struct super_block *sb) +int sb_is_blkdev_sb(struct super_block *sb) { return sb == blockdev_superblock; } diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 3be57189efd5..cabdece4cb39 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -68,7 +68,7 @@ static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) { struct super_block *sb = inode->i_sb; - if (strcmp(sb->s_type->name, "bdev") == 0) + if (sb_is_blkdev_sb(sb)) return inode->i_mapping->backing_dev_info; return sb->s_bdi; @@ -250,11 +250,13 @@ static int move_expired_inodes(struct list_head *delaying_queue, if (work->older_than_this && inode_dirtied_after(inode, *work->older_than_this)) break; + list_move(&inode->i_wb_list, &tmp); + moved++; + if (sb_is_blkdev_sb(inode->i_sb)) + continue; if (sb && sb != inode->i_sb) do_sb_sort = 1; sb = inode->i_sb; - list_move(&inode->i_wb_list, &tmp); - moved++; } /* just one sb in list, splice to dispatch_queue and we're done */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 65c2be22b601..61da2f1c8056 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2058,6 +2058,7 @@ extern struct super_block *freeze_bdev(struct block_device *); extern void emergency_thaw_all(void); extern int thaw_bdev(struct block_device *bdev, struct super_block *sb); extern int fsync_bdev(struct block_device *); +extern int sb_is_blkdev_sb(struct super_block *sb); #else static inline void bd_forget(struct inode *inode) {} static inline int sync_blockdev(struct block_device *bdev) { return 0; } @@ -2077,6 +2078,11 @@ static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb) static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg) { } + +static inline int sb_is_blkdev_sb(struct super_block *sb) +{ + return 0; +} #endif extern int sync_filesystem(struct super_block *); extern const struct file_operations def_blk_fops; -- cgit v1.2.3-58-ga151