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Commit fbe9cc4a authored by David S. Miller's avatar David S. Miller Committed by David S. Miller
Browse files

[AF_UNIX]: Use spinlock for unix_table_lock 



This lock is actually taken mostly as a writer,
so using a rwlock actually just makes performance
worse especially on chips like the Intel P4.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d83d8461

include/net/af_unix.h

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ extern void unix_gc(void); 
#define UNIX_HASH_SIZE	256



extern struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];

extern rwlock_t unix_table_lock;

extern spinlock_t unix_table_lock;



extern atomic_t unix_tot_inflight;

net/unix/af_unix.c

+17 −17
Original line number Diff line number Diff line
@@ -121,7 +121,7 @@ 
int sysctl_unix_max_dgram_qlen = 10;



struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];

DEFINE_RWLOCK(unix_table_lock);

DEFINE_SPINLOCK(unix_table_lock);

static atomic_t unix_nr_socks = ATOMIC_INIT(0);



#define unix_sockets_unbound	(&unix_socket_table[UNIX_HASH_SIZE])
@@ -130,7 +130,7 @@ static atomic_t unix_nr_socks = ATOMIC_INIT(0); 


/*

 *  SMP locking strategy:

 *    hash table is protected with rwlock unix_table_lock

 *    hash table is protected with spinlock unix_table_lock

 *    each socket state is protected by separate rwlock.

 */
@@ -214,16 +214,16 @@ static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 


static inline void unix_remove_socket(struct sock *sk)

{

	write_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);

	__unix_remove_socket(sk);

	write_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

}



static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)

{

	write_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);

	__unix_insert_socket(list, sk);

	write_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

}



static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname,
@@ -250,11 +250,11 @@ static inline struct sock *unix_find_socket_byname(struct sockaddr_un *sunname, 
{

	struct sock *s;



	read_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);

	s = __unix_find_socket_byname(sunname, len, type, hash);

	if (s)

		sock_hold(s);

	read_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

	return s;

}
@@ -263,7 +263,7 @@ static struct sock *unix_find_socket_byinode(struct inode *i) 
	struct sock *s;

	struct hlist_node *node;



	read_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);

	sk_for_each(s, node,

		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {

		struct dentry *dentry = unix_sk(s)->dentry;
@@ -276,7 +276,7 @@ static struct sock *unix_find_socket_byinode(struct inode *i) 
	}

	s = NULL;

found:

	read_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

	return s;

}
@@ -642,12 +642,12 @@ static int unix_autobind(struct socket *sock) 
	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);

	addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0));



	write_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);

	ordernum = (ordernum+1)&0xFFFFF;



	if (__unix_find_socket_byname(addr->name, addr->len, sock->type,

				      addr->hash)) {

		write_unlock(&unix_table_lock);

		spin_unlock(&unix_table_lock);

		/* Sanity yield. It is unusual case, but yet... */

		if (!(ordernum&0xFF))

			yield();
@@ -658,7 +658,7 @@ static int unix_autobind(struct socket *sock) 
	__unix_remove_socket(sk);

	u->addr = addr;

	__unix_insert_socket(&unix_socket_table[addr->hash], sk);

	write_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

	err = 0;



out:	up(&u->readsem);
@@ -791,7 +791,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
		addr->hash = UNIX_HASH_SIZE;

	}



	write_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);



	if (!sunaddr->sun_path[0]) {

		err = -EADDRINUSE;
@@ -814,7 +814,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
	__unix_insert_socket(list, sk);



out_unlock:

	write_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

out_up:

	up(&u->readsem);

out:
@@ -1916,7 +1916,7 @@ static struct sock *unix_seq_idx(int *iter, loff_t pos) 


static void *unix_seq_start(struct seq_file *seq, loff_t *pos)

{

	read_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);

	return *pos ? unix_seq_idx(seq->private, *pos - 1) : ((void *) 1);

}
@@ -1931,7 +1931,7 @@ static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 


static void unix_seq_stop(struct seq_file *seq, void *v)

{

	read_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);

}



static int unix_seq_show(struct seq_file *seq, void *v)

net/unix/garbage.c

+2 −2
Original line number Diff line number Diff line
@@ -182,7 +182,7 @@ void unix_gc(void) 
	if (down_trylock(&unix_gc_sem))

		return;



	read_lock(&unix_table_lock);

	spin_lock(&unix_table_lock);



	forall_unix_sockets(i, s)

	{
@@ -301,7 +301,7 @@ void unix_gc(void) 
		}

		u->gc_tree = GC_ORPHAN;

	}

	read_unlock(&unix_table_lock);

	spin_unlock(&unix_table_lock);



	/*

	 *	Here we are. Hitlist is filled. Die.