These two functions are the same except for what they call
to "check_established" and "hash" for a socket.

This saves half-a-kilo for ipv4 and ipv6.

 add/remove: 1/0 grow/shrink: 1/4 up/down: 582/-1128 (-546)
 function                                     old     new   delta
 __inet_hash_connect                            -     577    +577
 arp_ignore                                   108     113      +5
 static.hint                                    8       4      -4
 rt_worker_func                               376     372      -4
 inet6_hash_connect                           584      25    -559
 inet_hash_connect                            586      25    -561

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---
 include/net/inet_hashtables.h |    5 ++
 net/ipv4/inet_hashtables.c    |   32 +++++++++-----
 net/ipv6/inet6_hashtables.c   |   93 +----------------------------------------
 3 files changed, 28 insertions(+), 102 deletions(-)

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 761bdc0..a34a8f2 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -413,6 +413,11 @@ static inline struct sock *inet_lookup(struct inet_hashinfo *hashinfo,
 	return sk;
 }
 
+extern int __inet_hash_connect(struct inet_timewait_death_row *death_row,
+		struct sock *sk,
+		int (*check_established)(struct inet_timewait_death_row *,
+			struct sock *, __u16, struct inet_timewait_sock **),
+		void (*hash)(struct inet_hashinfo *, struct sock *));
 extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
 			     struct sock *sk);
 #endif /* _INET_HASHTABLES_H */
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 619c63c..b93d40f 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -348,11 +348,11 @@ void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(__inet_hash);
 
-/*
- * Bind a port for a connect operation and hash it.
- */
-int inet_hash_connect(struct inet_timewait_death_row *death_row,
-		      struct sock *sk)
+int __inet_hash_connect(struct inet_timewait_death_row *death_row,
+		struct sock *sk,
+		int (*check_established)(struct inet_timewait_death_row *,
+			struct sock *, __u16, struct inet_timewait_sock **),
+		void (*hash)(struct inet_hashinfo *, struct sock *))
 {
 	struct inet_hashinfo *hinfo = death_row->hashinfo;
 	const unsigned short snum = inet_sk(sk)->num;
@@ -385,9 +385,8 @@ int inet_hash_connect(struct inet_timewait_death_row *death_row,
 					BUG_TRAP(!hlist_empty(&tb->owners));
 					if (tb->fastreuse >= 0)
 						goto next_port;
-					if (!__inet_check_established(death_row,
-								      sk, port,
-								      &tw))
+					if (!check_established(death_row, sk,
+								port, &tw))
 						goto ok;
 					goto next_port;
 				}
@@ -415,7 +414,7 @@ ok:
 		inet_bind_hash(sk, tb, port);
 		if (sk_unhashed(sk)) {
 			inet_sk(sk)->sport = htons(port);
-			__inet_hash_nolisten(hinfo, sk);
+			hash(hinfo, sk);
 		}
 		spin_unlock(&head->lock);
 
@@ -432,17 +431,28 @@ ok:
 	tb  = inet_csk(sk)->icsk_bind_hash;
 	spin_lock_bh(&head->lock);
 	if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
-		__inet_hash_nolisten(hinfo, sk);
+		hash(hinfo, sk);
 		spin_unlock_bh(&head->lock);
 		return 0;
 	} else {
 		spin_unlock(&head->lock);
 		/* No definite answer... Walk to established hash table */
-		ret = __inet_check_established(death_row, sk, snum, NULL);
+		ret = check_established(death_row, sk, snum, NULL);
 out:
 		local_bh_enable();
 		return ret;
 	}
 }
+EXPORT_SYMBOL_GPL(__inet_hash_connect);
+
+/*
+ * Bind a port for a connect operation and hash it.
+ */
+int inet_hash_connect(struct inet_timewait_death_row *death_row,
+		      struct sock *sk)
+{
+	return __inet_hash_connect(death_row, sk,
+			__inet_check_established, __inet_hash_nolisten);
+}
 
 EXPORT_SYMBOL_GPL(inet_hash_connect);
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 06b01be..ece6d0e 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -233,97 +233,8 @@ static inline u32 inet6_sk_port_offset(const struct sock *sk)
 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 		       struct sock *sk)
 {
-	struct inet_hashinfo *hinfo = death_row->hashinfo;
-	const unsigned short snum = inet_sk(sk)->num;
-	struct inet_bind_hashbucket *head;
-	struct inet_bind_bucket *tb;
-	int ret;
-
-	if (snum == 0) {
-		int i, port, low, high, remaining;
-		static u32 hint;
-		const u32 offset = hint + inet6_sk_port_offset(sk);
-		struct hlist_node *node;
-		struct inet_timewait_sock *tw = NULL;
-
-		inet_get_local_port_range(&low, &high);
-		remaining = (high - low) + 1;
-
-		local_bh_disable();
-		for (i = 1; i <= remaining; i++) {
-			port = low + (i + offset) % remaining;
-			head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
-			spin_lock(&head->lock);
-
-			/* Does not bother with rcv_saddr checks,
-			 * because the established check is already
-			 * unique enough.
-			 */
-			inet_bind_bucket_for_each(tb, node, &head->chain) {
-				if (tb->port == port) {
-					BUG_TRAP(!hlist_empty(&tb->owners));
-					if (tb->fastreuse >= 0)
-						goto next_port;
-					if (!__inet6_check_established(death_row,
-								       sk, port,
-								       &tw))
-						goto ok;
-					goto next_port;
-				}
-			}
-
-			tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
-						     head, port);
-			if (!tb) {
-				spin_unlock(&head->lock);
-				break;
-			}
-			tb->fastreuse = -1;
-			goto ok;
-
-		next_port:
-			spin_unlock(&head->lock);
-		}
-		local_bh_enable();
-
-		return -EADDRNOTAVAIL;
-
-ok:
-		hint += i;
-
-		/* Head lock still held and bh's disabled */
-		inet_bind_hash(sk, tb, port);
-		if (sk_unhashed(sk)) {
-			inet_sk(sk)->sport = htons(port);
-			__inet6_hash(hinfo, sk);
-		}
-		spin_unlock(&head->lock);
-
-		if (tw) {
-			inet_twsk_deschedule(tw, death_row);
-			inet_twsk_put(tw);
-		}
-
-		ret = 0;
-		goto out;
-	}
-
-	head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
-	tb   = inet_csk(sk)->icsk_bind_hash;
-	spin_lock_bh(&head->lock);
-
-	if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
-		__inet6_hash(hinfo, sk);
-		spin_unlock_bh(&head->lock);
-		return 0;
-	} else {
-		spin_unlock(&head->lock);
-		/* No definite answer... Walk to established hash table */
-		ret = __inet6_check_established(death_row, sk, snum, NULL);
-out:
-		local_bh_enable();
-		return ret;
-	}
+	return __inet_hash_connect(death_row, sk,
+			__inet6_check_established, __inet6_hash);
 }
 
 EXPORT_SYMBOL_GPL(inet6_hash_connect);
-- 
1.5.3.4

Em Thu, Jan 31, 2008 at 03:32:09PM +0300, Pavel Emelyanov escreveu:
> These two functions are the same except for what they call
> to "check_established" and "hash" for a socket.
> 
> This saves half-a-kilo for ipv4 and ipv6.

Good stuff!

Yesterday I was perusing tcp_hash and I think we could have the hashinfo
pointer stored perhaps in sk->sk_prot.

That way we would be able to kill tcp_hash(), inet_put_port() could
receive just sk, etc.

What do you think?

- Arnaldo

From: Pavel Emelyanov <xemul@openvz.org>
Date: Thu, 31 Jan 2008 15:32:09 +0300

> These two functions are the same except for what they call
> to "check_established" and "hash" for a socket.
> 
> This saves half-a-kilo for ipv4 and ipv6.
> 
>  add/remove: 1/0 grow/shrink: 1/4 up/down: 582/-1128 (-546)
>  function                                     old     new   delta
>  __inet_hash_connect                            -     577    +577
>  arp_ignore                                   108     113      +5
>  static.hint                                    8       4      -4
>  rt_worker_func                               376     372      -4
>  inet6_hash_connect                           584      25    -559
>  inet_hash_connect                            586      25    -561
> 
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

Applied.

From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Thu, 31 Jan 2008 11:01:53 -0200

> Em Thu, Jan 31, 2008 at 03:32:09PM +0300, Pavel Emelyanov escreveu:
> > These two functions are the same except for what they call
> > to "check_established" and "hash" for a socket.
> > 
> > This saves half-a-kilo for ipv4 and ipv6.
> 
> Good stuff!
> 
> Yesterday I was perusing tcp_hash and I think we could have the hashinfo
> pointer stored perhaps in sk->sk_prot.
> 
> That way we would be able to kill tcp_hash(), inet_put_port() could
> receive just sk, etc.
> 
> What do you think?

Sounds good to me.

Arnaldo Carvalho de Melo wrote:
> Em Thu, Jan 31, 2008 at 03:32:09PM +0300, Pavel Emelyanov escreveu:
>> These two functions are the same except for what they call
>> to "check_established" and "hash" for a socket.
>>
>> This saves half-a-kilo for ipv4 and ipv6.
> 
> Good stuff!
> 
> Yesterday I was perusing tcp_hash and I think we could have the hashinfo
> pointer stored perhaps in sk->sk_prot.
> 
> That way we would be able to kill tcp_hash(), inet_put_port() could
> receive just sk, etc.

But each proto will still have its own hashfn, so proto's 
callbacks will be called to hash/unhash sockets, so this will 
give us just one extra dereference. No?

> What do you think?

Hmmm... Even raw_hash, etc may become simpler. On the other hand
maybe this is a good idea, but I'm not very common with this code
yet to foresee such things in advance... I think that we should
try to prepare a patch and look, but if you have smth ready, then
it's better to review your stuff first.

> - Arnaldo
> 

Thanks,
Pavel

Em Thu, Jan 31, 2008 at 04:18:51PM +0300, Pavel Emelyanov escreveu:
> Arnaldo Carvalho de Melo wrote:
> > Em Thu, Jan 31, 2008 at 03:32:09PM +0300, Pavel Emelyanov escreveu:
> >> These two functions are the same except for what they call
> >> to "check_established" and "hash" for a socket.
> >>
> >> This saves half-a-kilo for ipv4 and ipv6.
> > 
> > Good stuff!
> > 
> > Yesterday I was perusing tcp_hash and I think we could have the hashinfo
> > pointer stored perhaps in sk->sk_prot.
> > 
> > That way we would be able to kill tcp_hash(), inet_put_port() could
> > receive just sk, etc.
> 
> But each proto will still have its own hashfn, so proto's 
> callbacks will be called to hash/unhash sockets, so this will 
> give us just one extra dereference. No?
> 
> > What do you think?
> 
> Hmmm... Even raw_hash, etc may become simpler. On the other hand
> maybe this is a good idea, but I'm not very common with this code
> yet to foresee such things in advance... I think that we should
> try to prepare a patch and look, but if you have smth ready, then
> it's better to review your stuff first.

gimme some minutes

- Arnaldo

Em Thu, Jan 31, 2008 at 11:39:55AM -0200, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Jan 31, 2008 at 04:18:51PM +0300, Pavel Emelyanov escreveu:
> > Arnaldo Carvalho de Melo wrote:
> > > Em Thu, Jan 31, 2008 at 03:32:09PM +0300, Pavel Emelyanov escreveu:
> > >> These two functions are the same except for what they call
> > >> to "check_established" and "hash" for a socket.
> > >>
> > >> This saves half-a-kilo for ipv4 and ipv6.
> > > 
> > > Good stuff!
> > > 
> > > Yesterday I was perusing tcp_hash and I think we could have the hashinfo
> > > pointer stored perhaps in sk->sk_prot.
> > > 
> > > That way we would be able to kill tcp_hash(), inet_put_port() could
> > > receive just sk, etc.
> > 
> > But each proto will still have its own hashfn, so proto's 
> > callbacks will be called to hash/unhash sockets, so this will 
> > give us just one extra dereference. No?
> > 
> > > What do you think?
> > 
> > Hmmm... Even raw_hash, etc may become simpler. On the other hand
> > maybe this is a good idea, but I'm not very common with this code
> > yet to foresee such things in advance... I think that we should
> > try to prepare a patch and look, but if you have smth ready, then
> > it's better to review your stuff first.
> 
> gimme some minutes

A bit more than minutes tho, but here it is, I'm testing it now.

Take a look and if testing is ok I'll submit it with a proper
description.

- Arnaldo

diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index fdff630..62a5b69 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -49,7 +49,7 @@ static inline int inet6_sk_ehashfn(const struct sock *sk)
 	return inet6_ehashfn(laddr, lport, faddr, fport);
 }
 
-extern void __inet6_hash(struct inet_hashinfo *hashinfo, struct sock *sk);
+extern void __inet6_hash(struct sock *sk);
 
 /*
  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 133cf30..f00f057 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -29,7 +29,6 @@
 #undef INET_CSK_CLEAR_TIMERS
 
 struct inet_bind_bucket;
-struct inet_hashinfo;
 struct tcp_congestion_ops;
 
 /*
@@ -59,6 +58,8 @@ struct inet_connection_sock_af_ops {
 				int level, int optname,
 				char __user *optval, int __user *optlen);
 	void	    (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
+	int	    (*bind_conflict)(const struct sock *sk,
+				     const struct inet_bind_bucket *tb);
 };
 
 /** inet_connection_sock - INET connection oriented sock
@@ -244,10 +245,7 @@ extern struct request_sock *inet_csk_search_req(const struct sock *sk,
 						const __be32 laddr);
 extern int inet_csk_bind_conflict(const struct sock *sk,
 				  const struct inet_bind_bucket *tb);
-extern int inet_csk_get_port(struct inet_hashinfo *hashinfo,
-			     struct sock *sk, unsigned short snum,
-			     int (*bind_conflict)(const struct sock *sk,
-						  const struct inet_bind_bucket *tb));
+extern int inet_csk_get_port(struct sock *sk, unsigned short snum);
 
 extern struct dst_entry* inet_csk_route_req(struct sock *sk,
 					    const struct request_sock *req);
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index c23c4ed..48ac620 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -221,9 +221,9 @@ static inline int inet_sk_listen_hashfn(const struct sock *sk)
 }
 
 /* Caller must disable local BH processing. */
-static inline void __inet_inherit_port(struct inet_hashinfo *table,
-				       struct sock *sk, struct sock *child)
+static inline void __inet_inherit_port(struct sock *sk, struct sock *child)
 {
+	struct inet_hashinfo *table = sk->sk_prot->hashinfo;
 	const int bhash = inet_bhashfn(inet_sk(child)->num, table->bhash_size);
 	struct inet_bind_hashbucket *head = &table->bhash[bhash];
 	struct inet_bind_bucket *tb;
@@ -235,15 +235,14 @@ static inline void __inet_inherit_port(struct inet_hashinfo *table,
 	spin_unlock(&head->lock);
 }
 
-static inline void inet_inherit_port(struct inet_hashinfo *table,
-				     struct sock *sk, struct sock *child)
+static inline void inet_inherit_port(struct sock *sk, struct sock *child)
 {
 	local_bh_disable();
-	__inet_inherit_port(table, sk, child);
+	__inet_inherit_port(sk, child);
 	local_bh_enable();
 }
 
-extern void inet_put_port(struct inet_hashinfo *table, struct sock *sk);
+extern void inet_put_port(struct sock *sk);
 
 extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);
 
@@ -266,41 +265,9 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
 		wake_up(&hashinfo->lhash_wait);
 }
 
-extern void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk);
-extern void __inet_hash_nolisten(struct inet_hashinfo *hinfo, struct sock *sk);
-
-static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
-{
-	if (sk->sk_state != TCP_CLOSE) {
-		local_bh_disable();
-		__inet_hash(hashinfo, sk);
-		local_bh_enable();
-	}
-}
-
-static inline void inet_unhash(struct inet_hashinfo *hashinfo, struct sock *sk)
-{
-	rwlock_t *lock;
-
-	if (sk_unhashed(sk))
-		goto out;
-
-	if (sk->sk_state == TCP_LISTEN) {
-		local_bh_disable();
-		inet_listen_wlock(hashinfo);
-		lock = &hashinfo->lhash_lock;
-	} else {
-		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
-		write_lock_bh(lock);
-	}
-
-	if (__sk_del_node_init(sk))
-		sock_prot_inuse_add(sk->sk_prot, -1);
-	write_unlock_bh(lock);
-out:
-	if (sk->sk_state == TCP_LISTEN)
-		wake_up(&hashinfo->lhash_wait);
-}
+extern void __inet_hash_nolisten(struct sock *sk);
+extern void inet_hash(struct sock *sk);
+extern void inet_unhash(struct sock *sk);
 
 extern struct sock *__inet_lookup_listener(struct net *net,
 					   struct inet_hashinfo *hashinfo,
@@ -425,7 +392,7 @@ extern int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		struct sock *sk,
 		int (*check_established)(struct inet_timewait_death_row *,
 			struct sock *, __u16, struct inet_timewait_sock **),
-		void (*hash)(struct inet_hashinfo *, struct sock *));
+			       void (*hash)(struct sock *sk));
 extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
 			     struct sock *sk);
 #endif /* _INET_HASHTABLES_H */
diff --git a/include/net/sock.h b/include/net/sock.h
index e3fb4c0..8a7889b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -496,6 +496,7 @@ extern int sk_wait_data(struct sock *sk, long *timeo);
 
 struct request_sock_ops;
 struct timewait_sock_ops;
+struct inet_hashinfo;
 
 /* Networking protocol blocks we attach to sockets.
  * socket layer -> transport layer interface
@@ -578,6 +579,8 @@ struct proto {
 	struct request_sock_ops	*rsk_prot;
 	struct timewait_sock_ops *twsk_prot;
 
+	struct inet_hashinfo	*hashinfo;
+
 	struct module		*owner;
 
 	char			name[32];
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index ebe59d9..287a62b 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -271,8 +271,6 @@ extern struct sk_buff	*dccp_make_response(struct sock *sk,
 
 extern int	   dccp_connect(struct sock *sk);
 extern int	   dccp_disconnect(struct sock *sk, int flags);
-extern void	   dccp_hash(struct sock *sk);
-extern void	   dccp_unhash(struct sock *sk);
 extern int	   dccp_getsockopt(struct sock *sk, int level, int optname,
 				   char __user *optval, int __user *optlen);
 extern int	   dccp_setsockopt(struct sock *sk, int level, int optname,
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index c982ad8..474075a 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -38,12 +38,6 @@
  */
 static struct socket *dccp_v4_ctl_socket;
 
-static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
-{
-	return inet_csk_get_port(&dccp_hashinfo, sk, snum,
-				 inet_csk_bind_conflict);
-}
-
 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 {
 	struct inet_sock *inet = inet_sk(sk);
@@ -408,8 +402,8 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	dccp_sync_mss(newsk, dst_mtu(dst));
 
-	__inet_hash_nolisten(&dccp_hashinfo, newsk);
-	__inet_inherit_port(&dccp_hashinfo, sk, newsk);
+	__inet_hash_nolisten(newsk);
+	__inet_inherit_port(sk, newsk);
 
 	return newsk;
 
@@ -898,6 +892,7 @@ static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
 	.getsockopt	   = ip_getsockopt,
 	.addr2sockaddr	   = inet_csk_addr2sockaddr,
 	.sockaddr_len	   = sizeof(struct sockaddr_in),
+	.bind_conflict	   = inet_csk_bind_conflict,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt = compat_ip_setsockopt,
 	.compat_getsockopt = compat_ip_getsockopt,
@@ -937,10 +932,10 @@ static struct proto dccp_v4_prot = {
 	.sendmsg		= dccp_sendmsg,
 	.recvmsg		= dccp_recvmsg,
 	.backlog_rcv		= dccp_v4_do_rcv,
-	.hash			= dccp_hash,
-	.unhash			= dccp_unhash,
+	.hash			= inet_hash,
+	.unhash			= inet_unhash,
 	.accept			= inet_csk_accept,
-	.get_port		= dccp_v4_get_port,
+	.get_port		= inet_csk_get_port,
 	.shutdown		= dccp_shutdown,
 	.destroy		= dccp_destroy_sock,
 	.orphan_count		= &dccp_orphan_count,
@@ -948,6 +943,7 @@ static struct proto dccp_v4_prot = {
 	.obj_size		= sizeof(struct dccp_sock),
 	.rsk_prot		= &dccp_request_sock_ops,
 	.twsk_prot		= &dccp_timewait_sock_ops,
+	.hashinfo		= &dccp_hashinfo,
 #ifdef CONFIG_COMPAT
 	.compat_setsockopt	= compat_dccp_setsockopt,
 	.compat_getsockopt	= compat_dccp_getsockopt,
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index ed0a005..490333d 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -39,21 +39,15 @@ static struct socket *dccp_v6_ctl_socket;
 static struct inet_connection_sock_af_ops dccp_ipv6_mapped;
 static str