net: move inet_dport/inet_num in sock_common

commit 68835aba4d9b (net: optimize INET input path further)
moved some fields used for tcp/udp sockets lookup in the first cache
line of struct sock_common.

This patch moves inet_dport/inet_num as well, filling a 32bit hole
on 64 bit arches and reducing number of cache line misses in lookups.

Also change INET_MATCH()/INET_TW_MATCH() to perform the ports match
before addresses match, as this check is more discriminant.

Remove the hash check from MATCH() macros because we dont need to
re validate the hash value after taking a refcount on socket, and
use likely/unlikely compiler hints, as the sk_hash/hash check
makes the following conditional tests 100% predicted by cpu.

Introduce skc_addrpair/skc_portpair pair values to better
document the alignment requirements of the port/addr pairs
used in the various MATCH() macros, and remove some casts.

The namespace check can also be done at last.

This slightly improves TCP/UDP lookup times.

IP/TCP early demux needs inet->rx_dst_ifindex and
TCP needs inet->min_ttl, lets group them together in same cache line.

With help from Ben Hutchings & Joe Perches.

Idea of this patch came after Ling Ma proposal to move skc_hash
to the beginning of struct sock_common, and should allow him
to submit a final version of his patch. My tests show an improvement
doing so.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Joe Perches <joe@perches.com>
Cc: Ling Ma <ling.ma.program@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 5 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index c945fba4f543..c4132c1b63a8 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -132,6 +132,8 @@ struct net;
  *      @skc_rcv_saddr: Bound local IPv4 addr
  *      @skc_hash: hash value used with various protocol lookup tables
  *      @skc_u16hashes: two u16 hash values used by UDP lookup tables
+ *      @skc_dport: placeholder for inet_dport/tw_dport
+ *      @skc_num: placeholder for inet_num/tw_num
  *      @skc_family: network address family
  *      @skc_state: Connection state
  *      @skc_reuse: %SO_REUSEADDR setting
@@ -149,16 +151,29 @@ struct net;
  *      for struct sock and struct inet_timewait_sock.
  */
 struct sock_common {
-        /* skc_daddr and skc_rcv_saddr must be grouped :
-         * cf INET_MATCH() and INET_TW_MATCH()
+        /* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
+         * address on 64bit arches : cf INET_MATCH() and INET_TW_MATCH()
          */
-        __be32                  skc_daddr;
-        __be32                  skc_rcv_saddr;
-
+        union {
+                unsigned long   skc_addrpair;
+                struct {
+                        __be32  skc_daddr;
+                        __be32  skc_rcv_saddr;
+                };
+        };
         union  {
                 unsigned int    skc_hash;
                 __u16           skc_u16hashes[2];
         };
+        /* skc_dport && skc_num must be grouped as well */
+        union {
+                u32             skc_portpair;
+                struct {
+                        __be16  skc_dport;
+                        __u16   skc_num;
+                };
+        };
+
         unsigned short          skc_family;
         volatile unsigned char  skc_state;
         unsigned char           skc_reuse;