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>
diff --git a/include/net/sock.h b/include/net/sock.h
index 3482004..82e8603 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -105,10 +105,8 @@
/**
* 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 @@
* @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 :
+ * cf INET_MATCH() and INET_TW_MATCH()
*/
- 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 @@
#ifdef CONFIG_NET_NS
struct net *skc_net;
#endif
+ /*
+ * 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 @@
#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