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vfs: dont chain pipe/anon/socket on superblock s_inodes list

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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 <eric.dumazet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Eric Dumazet 2011-07-26 11:36:34 +02:00 committed by Al Viro
parent 5b9f456772
commit a209dfc7b0
5 changed files with 35 additions and 13 deletions
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2
fs/anon_inodes.c
View File

@ -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);

39
fs/inode.c
View File

@ -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);

2
fs/pipe.c
View File

@ -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)

3
include/linux/fs.h
View File

@ -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 *);

2
net/socket.c
View File

@ -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;