Commit 68835aba authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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net: optimize INET input path further

Followup of commit b178bb3d

 (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: default avatarEric Dumazet <>
Signed-off-by: default avatarDavid S. Miller <>
parent defb3519
......@@ -116,8 +116,9 @@ struct inet_sock {
struct ipv6_pinfo *pinet6;
/* 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;
......@@ -88,12 +88,6 @@ extern void inet_twdr_hangman(unsigned long data);
extern void inet_twdr_twkill_work(struct work_struct *work);
extern void inet_twdr_twcal_tick(unsigned long data);
#if (BITS_PER_LONG == 64)
struct inet_bind_bucket;
......@@ -117,15 +111,15 @@ struct inet_timewait_sock {
#define tw_hash __tw_common.skc_hash
#define tw_prot __tw_common.skc_prot
#define tw_net __tw_common.skc_net
#define tw_daddr __tw_common.skc_daddr
#define tw_rcv_saddr __tw_common.skc_rcv_saddr
int tw_timeout;
volatile unsigned char tw_substate;
/* 3 bits hole, try to pack */
unsigned char tw_rcv_wscale;
/* Socket demultiplex comparisons on incoming packets. */
/* these five are in inet_sock */
/* these three are in inet_sock */
__be16 tw_sport;
__be32 tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
__be32 tw_rcv_saddr;
__be16 tw_dport;
__u16 tw_num;
......@@ -191,10 +185,10 @@ static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
return (struct inet_timewait_sock *)sk;
static inline __be32 inet_rcv_saddr(const struct sock *sk)
static inline __be32 sk_rcv_saddr(const struct sock *sk)
return likely(sk->sk_state != TCP_TIME_WAIT) ?
inet_sk(sk)->inet_rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
/* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
return sk->__sk_common.skc_rcv_saddr;
extern void inet_twsk_put(struct inet_timewait_sock *tw);
......@@ -105,10 +105,8 @@ struct net;
* struct sock_common - minimal network layer representation of sockets
* @skc_node: main hash linkage for various protocol lookup tables
* @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
* @skc_refcnt: reference count
* @skc_tx_queue_mapping: tx queue number for this connection
* @skc_daddr: Foreign IPv4 addr
* @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_family: network address family
......@@ -119,20 +117,20 @@ struct net;
* @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
* @skc_prot: protocol handlers inside a network family
* @skc_net: reference to the network namespace of this socket
* @skc_node: main hash linkage for various protocol lookup tables
* @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
* @skc_tx_queue_mapping: tx queue number for this connection
* @skc_refcnt: reference count
* This is the minimal network layer representation of sockets, the header
* for struct sock and struct inet_timewait_sock.
struct sock_common {
* first fields are not copied in sock_copy()
/* skc_daddr and skc_rcv_saddr must be grouped :
union {
struct hlist_node skc_node;
struct hlist_nulls_node skc_nulls_node;
atomic_t skc_refcnt;
int skc_tx_queue_mapping;
__be32 skc_daddr;
__be32 skc_rcv_saddr;
union {
unsigned int skc_hash;
......@@ -150,6 +148,18 @@ struct sock_common {
struct net *skc_net;
* fields between dontcopy_begin/dontcopy_end
* are not copied in sock_copy()
int skc_dontcopy_begin[0];
union {
struct hlist_node skc_node;
struct hlist_nulls_node skc_nulls_node;
int skc_tx_queue_mapping;
atomic_t skc_refcnt;
int skc_dontcopy_end[0];
......@@ -232,7 +242,8 @@ struct sock {
#define sk_refcnt __sk_common.skc_refcnt
#define sk_tx_queue_mapping __sk_common.skc_tx_queue_mapping
#define sk_copy_start __sk_common.skc_hash
#define sk_dontcopy_begin __sk_common.skc_dontcopy_begin
#define sk_dontcopy_end __sk_common.skc_dontcopy_end
#define sk_hash __sk_common.skc_hash
#define sk_family __sk_common.skc_family
#define sk_state __sk_common.skc_state
......@@ -992,17 +992,18 @@ static inline void sock_lock_init(struct sock *sk)
* Copy all fields from osk to nsk but nsk->sk_refcnt must not change yet,
* even temporarly, because of RCU lookups. sk_node should also be left as is.
* We must not copy fields between sk_dontcopy_begin and sk_dontcopy_end
static void sock_copy(struct sock *nsk, const struct sock *osk)
void *sptr = nsk->sk_security;
BUILD_BUG_ON(offsetof(struct sock, sk_copy_start) !=
sizeof(osk->sk_node) + sizeof(osk->sk_refcnt) +
memcpy(&nsk->sk_copy_start, &osk->sk_copy_start,
osk->sk_prot->obj_size - offsetof(struct sock, sk_copy_start));
memcpy(nsk, osk, offsetof(struct sock, sk_dontcopy_begin));
memcpy(&nsk->sk_dontcopy_end, &osk->sk_dontcopy_end,
osk->sk_prot->obj_size - offsetof(struct sock, sk_dontcopy_end));
nsk->sk_security = sptr;
security_sk_clone(osk, nsk);
......@@ -55,7 +55,6 @@ EXPORT_SYMBOL(inet_get_local_port_range);
int inet_csk_bind_conflict(const struct sock *sk,
const struct inet_bind_bucket *tb)
const __be32 sk_rcv_saddr = inet_rcv_saddr(sk);
struct sock *sk2;
struct hlist_node *node;
int reuse = sk->sk_reuse;
......@@ -75,9 +74,9 @@ int inet_csk_bind_conflict(const struct sock *sk,
sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
if (!reuse || !sk2->sk_reuse ||
sk2->sk_state == TCP_LISTEN) {
const __be32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
if (!sk2_rcv_saddr || !sk_rcv_saddr ||
sk2_rcv_saddr == sk_rcv_saddr)
const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
sk2_rcv_saddr == sk_rcv_saddr(sk))
......@@ -54,8 +54,8 @@ int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
const struct in6_addr *sk_rcv_saddr6 = &inet6_sk(sk)->rcv_saddr;
const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
__be32 sk1_rcv_saddr = inet_sk(sk)->inet_rcv_saddr;
__be32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
__be32 sk1_rcv_saddr = sk_rcv_saddr(sk);
__be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
int sk_ipv6only = ipv6_only_sock(sk);
int sk2_ipv6only = inet_v6_ipv6only(sk2);
int addr_type = ipv6_addr_type(sk_rcv_saddr6);
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