From a209dfc7b0d94bd6fa94553c097836a2e6d0f0ba Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 26 Jul 2011 11:36:34 +0200 Subject: [PATCH] vfs: dont chain pipe/anon/socket on superblock s_inodes list Workloads using pipes and sockets hit inode_sb_list_lock contention. superblock s_inodes list is needed for quota, dirty, pagecache and fsnotify management. pipe/anon/socket fs are clearly not candidates for these. Signed-off-by: Eric Dumazet Reviewed-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/anon_inodes.c | 2 +- fs/inode.c | 39 ++++++++++++++++++++++++++++++--------- fs/pipe.c | 2 +- include/linux/fs.h | 3 ++- net/socket.c | 2 +- 5 files changed, 35 insertions(+), 13 deletions(-) diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 4d433d34736f..f11e43ed907d 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -187,7 +187,7 @@ EXPORT_SYMBOL_GPL(anon_inode_getfd); */ static struct inode *anon_inode_mkinode(void) { - struct inode *inode = new_inode(anon_inode_mnt->mnt_sb); + struct inode *inode = new_inode_pseudo(anon_inode_mnt->mnt_sb); if (!inode) return ERR_PTR(-ENOMEM); diff --git a/fs/inode.c b/fs/inode.c index 96c77b81167c..319b93b55570 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -362,9 +362,11 @@ EXPORT_SYMBOL_GPL(inode_sb_list_add); static inline void inode_sb_list_del(struct inode *inode) { - spin_lock(&inode_sb_list_lock); - list_del_init(&inode->i_sb_list); - spin_unlock(&inode_sb_list_lock); + if (!list_empty(&inode->i_sb_list)) { + spin_lock(&inode_sb_list_lock); + list_del_init(&inode->i_sb_list); + spin_unlock(&inode_sb_list_lock); + } } static unsigned long hash(struct super_block *sb, unsigned long hashval) @@ -796,6 +798,29 @@ unsigned int get_next_ino(void) } EXPORT_SYMBOL(get_next_ino); +/** + * new_inode_pseudo - obtain an inode + * @sb: superblock + * + * Allocates a new inode for given superblock. + * Inode wont be chained in superblock s_inodes list + * This means : + * - fs can't be unmount + * - quotas, fsnotify, writeback can't work + */ +struct inode *new_inode_pseudo(struct super_block *sb) +{ + struct inode *inode = alloc_inode(sb); + + if (inode) { + spin_lock(&inode->i_lock); + inode->i_state = 0; + spin_unlock(&inode->i_lock); + INIT_LIST_HEAD(&inode->i_sb_list); + } + return inode; +} + /** * new_inode - obtain an inode * @sb: superblock @@ -814,13 +839,9 @@ struct inode *new_inode(struct super_block *sb) spin_lock_prefetch(&inode_sb_list_lock); - inode = alloc_inode(sb); - if (inode) { - spin_lock(&inode->i_lock); - inode->i_state = 0; - spin_unlock(&inode->i_lock); + inode = new_inode_pseudo(sb); + if (inode) inode_sb_list_add(inode); - } return inode; } EXPORT_SYMBOL(new_inode); diff --git a/fs/pipe.c b/fs/pipe.c index 1b7f9af67ccf..0e0be1dc0f8e 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -948,7 +948,7 @@ static const struct dentry_operations pipefs_dentry_operations = { static struct inode * get_pipe_inode(void) { - struct inode *inode = new_inode(pipe_mnt->mnt_sb); + struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb); struct pipe_inode_info *pipe; if (!inode) diff --git a/include/linux/fs.h b/include/linux/fs.h index a6658043258a..cc363fa7bb82 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2310,7 +2310,8 @@ extern void __iget(struct inode * inode); extern void iget_failed(struct inode *); extern void end_writeback(struct inode *); extern void __destroy_inode(struct inode *); -extern struct inode *new_inode(struct super_block *); +extern struct inode *new_inode_pseudo(struct super_block *sb); +extern struct inode *new_inode(struct super_block *sb); extern void free_inode_nonrcu(struct inode *inode); extern int should_remove_suid(struct dentry *); extern int file_remove_suid(struct file *); diff --git a/net/socket.c b/net/socket.c index 02dc82db3d23..26ed35c7751e 100644 --- a/net/socket.c +++ b/net/socket.c @@ -467,7 +467,7 @@ static struct socket *sock_alloc(void) struct inode *inode; struct socket *sock; - inode = new_inode(sock_mnt->mnt_sb); + inode = new_inode_pseudo(sock_mnt->mnt_sb); if (!inode) return NULL; -- 2.20.1