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Commit a209dfc7 authored by Eric Dumazet's avatar Eric Dumazet Committed by Al Viro
Browse files

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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5b9f4567

fs/anon_inodes.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

fs/inode.c

+30 −9
Original line number Diff line number Diff line
@@ -362,10 +362,12 @@ EXPORT_SYMBOL_GPL(inode_sb_list_add); 


static inline void inode_sb_list_del(struct inode *inode)

{

	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);

fs/pipe.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

include/linux/fs.h

+2 −1
Original line number Diff line number Diff line
@@ -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 *);

net/socket.c

+1 −1
Original line number Diff line number Diff line
@@ -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;