This one is used in quite many places in the networking code and
seems to big to be inline.

After the patch net/ipv4/build-in.o loses 725 bytes:
add/remove: 1/0 grow/shrink: 0/5 up/down: 374/-1099 (-725)
function                                     old     new   delta
__inet_hash                                    -     374    +374
tcp_sacktag_write_queue                     2255    2254      -1
__inet_lookup_listener                       284     274     -10
tcp_v4_syn_recv_sock                         755     495    -260
tcp_v4_hash                                  389      40    -349
inet_hash_connect                           1165     686    -479

Exporting this is for dccp module.

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

---

 include/net/inet_hashtables.h |   27 ++-------------------------
 net/ipv4/inet_hashtables.c    |   27 +++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 37f6cb1..1a43125 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -264,31 +264,8 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
 		wake_up(&hashinfo->lhash_wait);
 }
 
-static inline void __inet_hash(struct inet_hashinfo *hashinfo,
-			       struct sock *sk, const int listen_possible)
-{
-	struct hlist_head *list;
-	rwlock_t *lock;
-
-	BUG_TRAP(sk_unhashed(sk));
-	if (listen_possible && sk->sk_state == TCP_LISTEN) {
-		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
-		lock = &hashinfo->lhash_lock;
-		inet_listen_wlock(hashinfo);
-	} else {
-		struct inet_ehash_bucket *head;
-		sk->sk_hash = inet_sk_ehashfn(sk);
-		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
-		list = &head->chain;
-		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
-		write_lock(lock);
-	}
-	__sk_add_node(sk, list);
-	sock_prot_inc_use(sk->sk_prot);
-	write_unlock(lock);
-	if (listen_possible && sk->sk_state == TCP_LISTEN)
-		wake_up(&hashinfo->lhash_wait);
-}
+extern void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
+		const int listen_possible);
 
 static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
 {
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 67704da..46f899b 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -267,6 +267,33 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
 					  inet->dport);
 }
 
+void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
+		const int listen_possible)
+{
+	struct hlist_head *list;
+	rwlock_t *lock;
+
+	BUG_TRAP(sk_unhashed(sk));
+	if (listen_possible && sk->sk_state == TCP_LISTEN) {
+		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+		lock = &hashinfo->lhash_lock;
+		inet_listen_wlock(hashinfo);
+	} else {
+		struct inet_ehash_bucket *head;
+		sk->sk_hash = inet_sk_ehashfn(sk);
+		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
+		list = &head->chain;
+		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+		write_lock(lock);
+	}
+	__sk_add_node(sk, list);
+	sock_prot_inc_use(sk->sk_prot);
+	write_unlock(lock);
+	if (listen_possible && sk->sk_state == TCP_LISTEN)
+		wake_up(&hashinfo->lhash_wait);
+}
+EXPORT_SYMBOL_GPL(__inet_hash);
+
 /*
  * Bind a port for a connect operation and hash it.
  */
-- 
1.5.3.4

Pavel Emelyanov a écrit :
> This one is used in quite many places in the networking code and
> seems to big to be inline.
> 
> After the patch net/ipv4/build-in.o loses 725 bytes:
> add/remove: 1/0 grow/shrink: 0/5 up/down: 374/-1099 (-725)
> function                                     old     new   delta
> __inet_hash                                    -     374    +374
> tcp_sacktag_write_queue                     2255    2254      -1
> __inet_lookup_listener                       284     274     -10
> tcp_v4_syn_recv_sock                         755     495    -260
> tcp_v4_hash                                  389      40    -349
> inet_hash_connect                           1165     686    -479
> 
> Exporting this is for dccp module.
> 
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
> 
> ---
> 
>  include/net/inet_hashtables.h |   27 ++-------------------------
>  net/ipv4/inet_hashtables.c    |   27 +++++++++++++++++++++++++++
>  2 files changed, 29 insertions(+), 25 deletions(-)
> 
> diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
> index 37f6cb1..1a43125 100644
> --- a/include/net/inet_hashtables.h
> +++ b/include/net/inet_hashtables.h
> @@ -264,31 +264,8 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
>  		wake_up(&hashinfo->lhash_wait);
>  }
>  
> -static inline void __inet_hash(struct inet_hashinfo *hashinfo,
> -			       struct sock *sk, const int listen_possible)
> -{
> -	struct hlist_head *list;
> -	rwlock_t *lock;
> -
> -	BUG_TRAP(sk_unhashed(sk));
> -	if (listen_possible && sk->sk_state == TCP_LISTEN) {
> -		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
> -		lock = &hashinfo->lhash_lock;
> -		inet_listen_wlock(hashinfo);
> -	} else {
> -		struct inet_ehash_bucket *head;
> -		sk->sk_hash = inet_sk_ehashfn(sk);
> -		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
> -		list = &head->chain;
> -		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
> -		write_lock(lock);
> -	}
> -	__sk_add_node(sk, list);
> -	sock_prot_inc_use(sk->sk_prot);
> -	write_unlock(lock);
> -	if (listen_possible && sk->sk_state == TCP_LISTEN)
> -		wake_up(&hashinfo->lhash_wait);
> -}
> +extern void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
> +		const int listen_possible);
>  
>  static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
>  {
> diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
> index 67704da..46f899b 100644
> --- a/net/ipv4/inet_hashtables.c
> +++ b/net/ipv4/inet_hashtables.c
> @@ -267,6 +267,33 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
>  					  inet->dport);
>  }
>  
> +void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
> +		const int listen_possible)
> +{
> +	struct hlist_head *list;
> +	rwlock_t *lock;
> +
> +	BUG_TRAP(sk_unhashed(sk));
> +	if (listen_possible && sk->sk_state == TCP_LISTEN) {
> +		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
> +		lock = &hashinfo->lhash_lock;
> +		inet_listen_wlock(hashinfo);
> +	} else {
> +		struct inet_ehash_bucket *head;
> +		sk->sk_hash = inet_sk_ehashfn(sk);
> +		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
> +		list = &head->chain;
> +		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
> +		write_lock(lock);
> +	}
> +	__sk_add_node(sk, list);
> +	sock_prot_inc_use(sk->sk_prot);
> +	write_unlock(lock);
> +	if (listen_possible && sk->sk_state == TCP_LISTEN)
> +		wake_up(&hashinfo->lhash_wait);
> +}
> +EXPORT_SYMBOL_GPL(__inet_hash);
> +
>  /*
>   * Bind a port for a connect operation and hash it.
>   */

If you un-inline this (good idea), I am not sure we still need listen_possible 
argument.

It was usefull only to help compiler to zap dead code (since it was known at 
compile time), now it only adds some extra test and argument passing.

Thank you

Eric Dumazet wrote:
> Pavel Emelyanov a écrit :
>> This one is used in quite many places in the networking code and
>> seems to big to be inline.
>>
>> After the patch net/ipv4/build-in.o loses 725 bytes:
>> add/remove: 1/0 grow/shrink: 0/5 up/down: 374/-1099 (-725)
>> function                                     old     new   delta
>> __inet_hash                                    -     374    +374
>> tcp_sacktag_write_queue                     2255    2254      -1
>> __inet_lookup_listener                       284     274     -10
>> tcp_v4_syn_recv_sock                         755     495    -260
>> tcp_v4_hash                                  389      40    -349
>> inet_hash_connect                           1165     686    -479
>>
>> Exporting this is for dccp module.
>>
>> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
>>
>> ---
>>
>>  include/net/inet_hashtables.h |   27 ++-------------------------
>>  net/ipv4/inet_hashtables.c    |   27 +++++++++++++++++++++++++++
>>  2 files changed, 29 insertions(+), 25 deletions(-)
>>
>> diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
>> index 37f6cb1..1a43125 100644
>> --- a/include/net/inet_hashtables.h
>> +++ b/include/net/inet_hashtables.h
>> @@ -264,31 +264,8 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
>>  		wake_up(&hashinfo->lhash_wait);
>>  }
>>  
>> -static inline void __inet_hash(struct inet_hashinfo *hashinfo,
>> -			       struct sock *sk, const int listen_possible)
>> -{
>> -	struct hlist_head *list;
>> -	rwlock_t *lock;
>> -
>> -	BUG_TRAP(sk_unhashed(sk));
>> -	if (listen_possible && sk->sk_state == TCP_LISTEN) {
>> -		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
>> -		lock = &hashinfo->lhash_lock;
>> -		inet_listen_wlock(hashinfo);
>> -	} else {
>> -		struct inet_ehash_bucket *head;
>> -		sk->sk_hash = inet_sk_ehashfn(sk);
>> -		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
>> -		list = &head->chain;
>> -		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
>> -		write_lock(lock);
>> -	}
>> -	__sk_add_node(sk, list);
>> -	sock_prot_inc_use(sk->sk_prot);
>> -	write_unlock(lock);
>> -	if (listen_possible && sk->sk_state == TCP_LISTEN)
>> -		wake_up(&hashinfo->lhash_wait);
>> -}
>> +extern void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
>> +		const int listen_possible);
>>  
>>  static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
>>  {
>> diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
>> index 67704da..46f899b 100644
>> --- a/net/ipv4/inet_hashtables.c
>> +++ b/net/ipv4/inet_hashtables.c
>> @@ -267,6 +267,33 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
>>  					  inet->dport);
>>  }
>>  
>> +void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
>> +		const int listen_possible)
>> +{
>> +	struct hlist_head *list;
>> +	rwlock_t *lock;
>> +
>> +	BUG_TRAP(sk_unhashed(sk));
>> +	if (listen_possible && sk->sk_state == TCP_LISTEN) {
>> +		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
>> +		lock = &hashinfo->lhash_lock;
>> +		inet_listen_wlock(hashinfo);
>> +	} else {
>> +		struct inet_ehash_bucket *head;
>> +		sk->sk_hash = inet_sk_ehashfn(sk);
>> +		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
>> +		list = &head->chain;
>> +		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
>> +		write_lock(lock);
>> +	}
>> +	__sk_add_node(sk, list);
>> +	sock_prot_inc_use(sk->sk_prot);
>> +	write_unlock(lock);
>> +	if (listen_possible && sk->sk_state == TCP_LISTEN)
>> +		wake_up(&hashinfo->lhash_wait);
>> +}
>> +EXPORT_SYMBOL_GPL(__inet_hash);
>> +
>>  /*
>>   * Bind a port for a connect operation and hash it.
>>   */
> 
> If you un-inline this (good idea), I am not sure we still need listen_possible 
> argument.
> 
> It was usefull only to help compiler to zap dead code (since it was known at 
> compile time), now it only adds some extra test and argument passing.

Hm... I've tried to address this issue and got worse result - minus
600 bytes (vs minus 725). So, what would be more preferable - get a 
smaller code with one extra 'if' or get a bit larger code without it?

> Thank you

Thanks,
Pavel

Pavel Emelyanov a écrit :
> Eric Dumazet wrote:
>> Pavel Emelyanov a écrit :
>>> This one is used in quite many places in the networking code and
>>> seems to big to be inline.
>>>
>>> After the patch net/ipv4/build-in.o loses 725 bytes:
>>> add/remove: 1/0 grow/shrink: 0/5 up/down: 374/-1099 (-725)
>>> function                                     old     new   delta
>>> __inet_hash                                    -     374    +374
>>> tcp_sacktag_write_queue                     2255    2254      -1
>>> __inet_lookup_listener                       284     274     -10
>>> tcp_v4_syn_recv_sock                         755     495    -260
>>> tcp_v4_hash                                  389      40    -349
>>> inet_hash_connect                           1165     686    -479
>>>
>>> Exporting this is for dccp module.
>>>
>>> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
>>>
>>> ---
>>>
>>>  include/net/inet_hashtables.h |   27 ++-------------------------
>>>  net/ipv4/inet_hashtables.c    |   27 +++++++++++++++++++++++++++
>>>  2 files changed, 29 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
>>> index 37f6cb1..1a43125 100644
>>> --- a/include/net/inet_hashtables.h
>>> +++ b/include/net/inet_hashtables.h
>>> @@ -264,31 +264,8 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
>>>  		wake_up(&hashinfo->lhash_wait);
>>>  }
>>>  
>>> -static inline void __inet_hash(struct inet_hashinfo *hashinfo,
>>> -			       struct sock *sk, const int listen_possible)
>>> -{
>>> -	struct hlist_head *list;
>>> -	rwlock_t *lock;
>>> -
>>> -	BUG_TRAP(sk_unhashed(sk));
>>> -	if (listen_possible && sk->sk_state == TCP_LISTEN) {
>>> -		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
>>> -		lock = &hashinfo->lhash_lock;
>>> -		inet_listen_wlock(hashinfo);
>>> -	} else {
>>> -		struct inet_ehash_bucket *head;
>>> -		sk->sk_hash = inet_sk_ehashfn(sk);
>>> -		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
>>> -		list = &head->chain;
>>> -		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
>>> -		write_lock(lock);
>>> -	}
>>> -	__sk_add_node(sk, list);
>>> -	sock_prot_inc_use(sk->sk_prot);
>>> -	write_unlock(lock);
>>> -	if (listen_possible && sk->sk_state == TCP_LISTEN)
>>> -		wake_up(&hashinfo->lhash_wait);
>>> -}
>>> +extern void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
>>> +		const int listen_possible);
>>>  
>>>  static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
>>>  {
>>> diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
>>> index 67704da..46f899b 100644
>>> --- a/net/ipv4/inet_hashtables.c
>>> +++ b/net/ipv4/inet_hashtables.c
>>> @@ -267,6 +267,33 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
>>>  					  inet->dport);
>>>  }
>>>  
>>> +void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
>>> +		const int listen_possible)
>>> +{
>>> +	struct hlist_head *list;
>>> +	rwlock_t *lock;
>>> +
>>> +	BUG_TRAP(sk_unhashed(sk));
>>> +	if (listen_possible && sk->sk_state == TCP_LISTEN) {
>>> +		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
>>> +		lock = &hashinfo->lhash_lock;
>>> +		inet_listen_wlock(hashinfo);
>>> +	} else {
>>> +		struct inet_ehash_bucket *head;
>>> +		sk->sk_hash = inet_sk_ehashfn(sk);
>>> +		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
>>> +		list = &head->chain;
>>> +		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
>>> +		write_lock(lock);
>>> +	}
>>> +	__sk_add_node(sk, list);
>>> +	sock_prot_inc_use(sk->sk_prot);
>>> +	write_unlock(lock);
>>> +	if (listen_possible && sk->sk_state == TCP_LISTEN)
>>> +		wake_up(&hashinfo->lhash_wait);
>>> +}
>>> +EXPORT_SYMBOL_GPL(__inet_hash);
>>> +
>>>  /*
>>>   * Bind a port for a connect operation and hash it.
>>>   */
>> If you un-inline this (good idea), I am not sure we still need listen_possible 
>> argument.
>>
>> It was usefull only to help compiler to zap dead code (since it was known at 
>> compile time), now it only adds some extra test and argument passing.
> 
> Hm... I've tried to address this issue and got worse result - minus
> 600 bytes (vs minus 725). So, what would be more preferable - get a 
> smaller code with one extra 'if' or get a bit larger code without it?
> 

Strange... What I meant is always assume listen_possible is true.

The if (sk->sk_state == TCP_LISTEN) will finally see the truth.

I did a test here on x86 gcc-4.2.2 and saved 32 bytes.

Eric Dumazet wrote:
> Pavel Emelyanov a écrit :
>> Eric Dumazet wrote:
>>> Pavel Emelyanov a écrit :
>>>> This one is used in quite many places in the networking code and
>>>> seems to big to be inline.
>>>>
>>>> After the patch net/ipv4/build-in.o loses 725 bytes:
>>>> add/remove: 1/0 grow/shrink: 0/5 up/down: 374/-1099 (-725)
>>>> function                                     old     new   delta
>>>> __inet_hash                                    -     374    +374
>>>> tcp_sacktag_write_queue                     2255    2254      -1
>>>> __inet_lookup_listener                       284     274     -10
>>>> tcp_v4_syn_recv_sock                         755     495    -260
>>>> tcp_v4_hash                                  389      40    -349
>>>> inet_hash_connect                           1165     686    -479
>>>>
>>>> Exporting this is for dccp module.
>>>>
>>>> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
>>>>
>>>> ---
>>>>
>>>>  include/net/inet_hashtables.h |   27 ++-------------------------
>>>>  net/ipv4/inet_hashtables.c    |   27 +++++++++++++++++++++++++++
>>>>  2 files changed, 29 insertions(+), 25 deletions(-)
>>>>
>>>> diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
>>>> index 37f6cb1..1a43125 100644
>>>> --- a/include/net/inet_hashtables.h
>>>> +++ b/include/net/inet_hashtables.h
>>>> @@ -264,31 +264,8 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
>>>>  		wake_up(&hashinfo->lhash_wait);
>>>>  }
>>>>  
>>>> -static inline void __inet_hash(struct inet_hashinfo *hashinfo,
>>>> -			       struct sock *sk, const int listen_possible)
>>>> -{
>>>> -	struct hlist_head *list;
>>>> -	rwlock_t *lock;
>>>> -
>>>> -	BUG_TRAP(sk_unhashed(sk));
>>>> -	if (listen_possible && sk->sk_state == TCP_LISTEN) {
>>>> -		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
>>>> -		lock = &hashinfo->lhash_lock;
>>>> -		inet_listen_wlock(hashinfo);
>>>> -	} else {
>>>> -		struct inet_ehash_bucket *head;
>>>> -		sk->sk_hash = inet_sk_ehashfn(sk);
>>>> -		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
>>>> -		list = &head->chain;
>>>> -		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
>>>> -		write_lock(lock);
>>>> -	}
>>>> -	__sk_add_node(sk, list);
>>>> -	sock_prot_inc_use(sk->sk_prot);
>>>> -	write_unlock(lock);
>>>> -	if (listen_possible && sk->sk_state == TCP_LISTEN)
>>>> -		wake_up(&hashinfo->lhash_wait);
>>>> -}
>>>> +extern void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
>>>> +		const int listen_possible);
>>>>  
>>>>  static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
>>>>  {
>>>> diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
>>>> index 67704da..46f899b 100644
>>>> --- a/net/ipv4/inet_hashtables.c
>>>> +++ b/net/ipv4/inet_hashtables.c
>>>> @@ -267,6 +267,33 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
>>>>  					  inet->dport);
>>>>  }
>>>>  
>>>> +void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk,
>>>> +		const int listen_possible)
>>>> +{
>>>> +	struct hlist_head *list;
>>>> +	rwlock_t *lock;
>>>> +
>>>> +	BUG_TRAP(sk_unhashed(sk));
>>>> +	if (listen_possible && sk->sk_state == TCP_LISTEN) {
>>>> +		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
>>>> +		lock = &hashinfo->lhash_lock;
>>>> +		inet_listen_wlock(hashinfo);
>>>> +	} else {
>>>> +		struct inet_ehash_bucket *head;
>>>> +		sk->sk_hash = inet_sk_ehashfn(sk);
>>>> +		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
>>>> +		list = &head->chain;
>>>> +		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
>>>> +		write_lock(lock);
>>>> +	}
>>>> +	__sk_add_node(sk, list);
>>>> +	sock_prot_inc_use(sk->sk_prot);
>>>> +	write_unlock(lock);
>>>> +	if (listen_possible && sk->sk_state == TCP_LISTEN)
>>>> +		wake_up(&hashinfo->lhash_wait);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(__inet_hash);
>>>> +
>>>>  /*
>>>>   * Bind a port for a connect operation and hash it.
>>>>   */
>>> If you un-inline this (good idea), I am not sure we still need listen_possible 
>>> argument.
>>>
>>> It was usefull only to help compiler to zap dead code (since it was known at 
>>> compile time), now it only adds some extra test and argument passing.
>> Hm... I've tried to address this issue and got worse result - minus
>> 600 bytes (vs minus 725). So, what would be more preferable - get a 
>> smaller code with one extra 'if' or get a bit larger code without it?
>>
> 
> Strange... What I meant is always assume listen_possible is true.

That's not truth, if I get you right. The __inet_hash() is called
with 0, from all the places except for the inet_hash() one.

> The if (sk->sk_state == TCP_LISTEN) will finally see the truth.
> 
> I did a test here on x86 gcc-4.2.2 and saved 32 bytes.
> 
> 
> 

Thanks,
Pavel

Pavel Emelyanov a écrit :
> Eric Dumazet wrote:
>> Pavel Emelyanov a écrit :
>>> Eric Dumazet wrote:
>>>> If you un-inline this (good idea), I am not sure we still need listen_possible 
>>>> argument.
>>>>
>>>> It was usefull only to help compiler to zap dead code (since it was known at 
>>>> compile time), now it only adds some extra test and argument passing.
>>> Hm... I've tried to address this issue and got worse result - minus
>>> 600 bytes (vs minus 725). So, what would be more preferable - get a 
>>> smaller code with one extra 'if' or get a bit larger code without it?
>>>
>> Strange... What I meant is always assume listen_possible is true.
> 
> That's not truth, if I get you right. The __inet_hash() is called
> with 0, from all the places except for the inet_hash() one.

OK, but on cases with 0, sk->sk_state is != TCP_LISTEN, unless I am mistaken.


> 
>> The if (sk->sk_state == TCP_LISTEN) will finally see the truth.
>>
>> I did a test here on x86 gcc-4.2.2 and saved 32 bytes.
>>
>>
>>
> 
> Thanks,
> Pavel
> 
>

From: Eric Dumazet <dada1@cosmosbay.com>
Date: Wed, 19 Dec 2007 18:15:20 +0100

> Pavel Emelyanov a écrit :
> > That's not truth, if I get you right. The __inet_hash() is called
> > with 0, from all the places except for the inet_hash() one.
> 
> OK, but on cases with 0, sk->sk_state is != TCP_LISTEN, unless I am mistaken.

This is true.

This one is used in quite many places in the networking code and
seems to big to be inline.

After the patch net/ipv4/build-in.o loses ~650 bytes:
add/remove: 2/0 grow/shrink: 0/5 up/down: 461/-1114 (-653)
function                                     old     new   delta
__inet_hash_nolisten                           -     282    +282
__inet_hash                                    -     179    +179
tcp_sacktag_write_queue                     2255    2254      -1
__inet_lookup_listener                       284     274     -10
tcp_v4_syn_recv_sock                         755     493    -262
tcp_v4_hash                                  389      35    -354
inet_hash_connect                           1086     599    -487

This version addresses the issue pointed by Eric, that
while being inline this function was optimized by gcc
in respect to the 'listen_possible' argument.

(Patches 2 and 3 in this series are still applied after this)

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

---

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index fef4442..65ddb25 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -264,37 +264,14 @@ static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
 		wake_up(&hashinfo->lhash_wait);
 }
 
-static inline void __inet_hash(struct inet_hashinfo *hashinfo,
-			       struct sock *sk, const int listen_possible)
-{
-	struct hlist_head *list;
-	rwlock_t *lock;
-
-	BUG_TRAP(sk_unhashed(sk));
-	if (listen_possible && sk->sk_state == TCP_LISTEN) {
-		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
-		lock = &hashinfo->lhash_lock;
-		inet_listen_wlock(hashinfo);
-	} else {
-		struct inet_ehash_bucket *head;
-		sk->sk_hash = inet_sk_ehashfn(sk);
-		head = inet_ehash_bucket(hashinfo, sk->sk_hash);
-		list = &head->chain;
-		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
-		write_lock(lock);
-	}
-	__sk_add_node(sk, list);
-	sock_prot_inc_use(sk->sk_prot);
-	write_unlock(lock);
-	if (listen_possible && sk->sk_state == TCP_LISTEN)
-		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, 1);
+		__inet_hash(hashinfo, sk);
 		local_bh_enable();
 	}
 }
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 02fc91c..f450df2 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -408,7 +408,7 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	dccp_sync_mss(newsk, dst_mtu(dst));
 
-	__inet_hash(&dccp_hashinfo, newsk, 0);
+	__inet_hash_nolisten(&dccp_hashinfo, newsk);
 	__inet_inherit_port(&dccp_hashinfo, sk, newsk);
 
 	return newsk;
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index b07e2d3..2e5814a 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -305,6 +305,48 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
 					  inet->dport);
 }
 
+void __inet_hash_nolisten(struct inet_hashinfo *hashinfo, struct sock *sk)
+{
+	struct hlist_head *list;
+	rwlock_t *lock;
+	struct inet_ehash_bucket *head;
+
+	BUG_TRAP(sk_unhashed(sk));
+
+	sk->sk_hash = inet_sk_ehashfn(sk);
+	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
+	list = &head->chain;
+	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+
+	write_lock(lock);
+	__sk_add_node(sk, list);
+	sock_prot_inc_use(sk->sk_prot);
+	write_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
+
+void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk)
+{
+	struct hlist_head *list;
+	rwlock_t *lock;
+
+	if (sk->sk_state != TCP_LISTEN) {
+		__inet_hash_nolisten(hashinfo, sk);
+		return;
+	}
+
+	BUG_TRAP(sk_unhashed(sk));
+	list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+	lock = &hashinfo->lhash_lock;
+
+	inet_listen_wlock(hashinfo);
+	__sk_add_node(sk, list);
+	sock_prot_inc_use(sk->sk_prot);
+	write_unlock(lock);
+	wake_up(&hashinfo->lhash_wait);
+}
+EXPORT_SYMBOL_GPL(__inet_hash);
+
 /*
  * Bind a port for a connect operation and hash it.
  */
@@ -372,7 +414,7 @@ ok:
 		inet_bind_hash(sk, tb, port);
 		if (sk_unhashed(sk)) {
 			inet_sk(sk)->sport = htons(port);
-			__inet_hash(hinfo, sk, 0);
+			__inet_hash_nolisten(hinfo, sk);
 		}
 		spin_unlock(&head->lock);
 
@@ -389,7 +431,7 @@ 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(hinfo, sk, 0);
+		__inet_hash_nolisten(hinfo, sk);
 		spin_unlock_bh(&head->lock);
 		return 0;
 	} else {
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 652c323..fc9bdd8 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1478,7 +1478,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 	}
 #endif
 
-	__inet_hash(&tcp_hashinfo, newsk, 0);
+	__inet_hash_nolisten(&tcp_hashinfo, newsk);
 	__inet_inherit_port(&tcp_hashinfo, sk, newsk);
 
 	return newsk;

From: Pavel Emelyanov <xemul@openvz.org>
Date: Thu, 20 Dec 2007 12:46:07 +0300

> This one is used in quite many places in the networking code and
> seems to big to be inline.
> 
> After the patch net/ipv4/build-in.o loses ~650 bytes:
> add/remove: 2/0 grow/shrink: 0/5 up/down: 461/-1114 (-653)
> function                                     old     new   delta
> __inet_hash_nolisten                           -     282    +282
> __inet_hash                                    -     179    +179
> tcp_sacktag_write_queue                     2255    2254      -1
> __inet_lookup_listener                       284     274     -10
> tcp_v4_syn_recv_sock                         755     493    -262
> tcp_v4_hash                                  389      35    -354
> inet_hash_connect                           1086     599    -487
> 
> This version addresses the issue pointed by Eric, that
> while being inline this function was optimized by gcc
> in respect to the 'listen_possible' argument.
> 
> (Patches 2 and 3 in this series are still applied after this)
> 
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

Applied.