net: optimize INET input path further

Followup of commit b178bb3dfc30 (net: reorder struct sock fields)

Optimize INET input path a bit further, by :

1) moving sk_refcnt close to sk_lock.

This reduces number of dirtied cache lines by one on 64bit arches (and
64 bytes cache line size).

2) moving inet_daddr & inet_rcv_saddr at the beginning of sk

(same cache line than hash / family / bound_dev_if / nulls_node)

This reduces number of accessed cache lines in lookups by one, and dont
increase size of inet and timewait socks.
inet and tw sockets now share same place-holder for these fields.

Before patch :

offsetof(struct sock, sk_refcnt) = 0x10
offsetof(struct sock, sk_lock) = 0x40
offsetof(struct sock, sk_receive_queue) = 0x60
offsetof(struct inet_sock, inet_daddr) = 0x270
offsetof(struct inet_sock, inet_rcv_saddr) = 0x274

After patch :

offsetof(struct sock, sk_refcnt) = 0x44
offsetof(struct sock, sk_lock) = 0x48
offsetof(struct sock, sk_receive_queue) = 0x68
offsetof(struct inet_sock, inet_daddr) = 0x0
offsetof(struct inet_sock, inet_rcv_saddr) = 0x4

compute_score() (udp or tcp) now use a single cache line per ignored
item, instead of two.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 8945f9fb192a..8181498fa96c 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -116,8 +116,9 @@ struct inet_sock {
         struct ipv6_pinfo       *pinet6;
 #endif
         /* Socket demultiplex comparisons on incoming packets. */
-        __be32                  inet_daddr;
-        __be32                  inet_rcv_saddr;
+#define inet_daddr              sk.__sk_common.skc_daddr
+#define inet_rcv_saddr          sk.__sk_common.skc_rcv_saddr
+
         __be16                  inet_dport;
         __u16                   inet_num;
         __be32                  inet_saddr;