[Devel] [PATCH 1/2] Uninline the sk_stream_alloc_pskb

[Pavel Emelyanov]

This function seems too big for inlining. Indeed, it saves
half-a-kilo when uninlined:

add/remove: 1/0 grow/shrink: 0/7 up/down: 195/-719 (-524)
function                                     old     new   delta
sk_stream_alloc_pskb                           -     195    +195
ip_rt_init                                   529     525      -4
__inet_lookup_listener                       284     274     -10
tcp_sendmsg                                 2583    2486     -97
tcp_sendpage                                1449    1305    -144
tso_fragment                                 417     267    -150
tcp_fragment                                1149     992    -157
__tcp_push_pending_frames                   1998    1841    -157

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

---

diff --git a/include/net/sock.h b/include/net/sock.h
index 67e35c7..492dc4a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1230,33 +1230,8 @@ static inline void sk_stream_moderate_sndbuf(struct sock *sk)
 	}
 }
 
-static inline struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,
-						   int size, int mem,
-						   gfp_t gfp)
-{
-	struct sk_buff *skb;
-
-	/* The TCP header must be at least 32-bit aligned.  */
-	size = ALIGN(size, 4);
-
-	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
-	if (skb) {
-		skb->truesize += mem;
-		if (sk_stream_wmem_schedule(sk, skb->truesize)) {
-			/*
-			 * Make sure that we have exactly size bytes
-			 * available to the caller, no more, no less.
-			 */
-			skb_reserve(skb, skb_tailroom(skb) - size);
-			return skb;
-		}
-		__kfree_skb(skb);
-	} else {
-		sk->sk_prot->enter_memory_pressure();
-		sk_stream_moderate_sndbuf(sk);
-	}
-	return NULL;
-}
+struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,
+		int size, int mem, gfp_t gfp);
 
 static inline struct sk_buff *sk_stream_alloc_skb(struct sock *sk,
 						  int size,
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8e65182..0dfda20 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -501,6 +501,33 @@ static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 	}
 }
 
+struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,
+		int size, int mem, gfp_t gfp)
+{
+	struct sk_buff *skb;
+
+	/* The TCP header must be at least 32-bit aligned.  */
+	size = ALIGN(size, 4);
+
+	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
+	if (skb) {
+		skb->truesize += mem;
+		if (sk_stream_wmem_schedule(sk, skb->truesize)) {
+			/*
+			 * Make sure that we have exactly size bytes
+			 * available to the caller, no more, no less.
+			 */
+			skb_reserve(skb, skb_tailroom(skb) - size);
+			return skb;
+		}
+		__kfree_skb(skb);
+	} else {
+		sk->sk_prot->enter_memory_pressure();
+		sk_stream_moderate_sndbuf(sk);
+	}
+	return NULL;
+}
+
 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
 			 size_t psize, int flags)
 {
-- 
1.5.3.4