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authorEric Dumazet <eric.dumazet@gmail.com>2010-11-30 22:04:07 +0300
committerDavid S. Miller <davem@davemloft.net>2010-12-10 07:05:58 +0300
commit68835aba4d9b74e2f94106d13b6a4bddc447c4c8 (patch)
tree468a9465acfa027791facef13fb6ef5129dda257 /net/core/sock.c
parentdefb3519a64141608725e2dac5a5aa9a3c644bae (diff)
downloadlinux-68835aba4d9b74e2f94106d13b6a4bddc447c4c8.tar.xz
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>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index fb6080111461..bcdb6ff6e621 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -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)
{
#ifdef CONFIG_SECURITY_NETWORK
void *sptr = nsk->sk_security;
#endif
- BUILD_BUG_ON(offsetof(struct sock, sk_copy_start) !=
- sizeof(osk->sk_node) + sizeof(osk->sk_refcnt) +
- sizeof(osk->sk_tx_queue_mapping));
- 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));
+
#ifdef CONFIG_SECURITY_NETWORK
nsk->sk_security = sptr;
security_sk_clone(osk, nsk);