From fa438ccfdfd3f6db02c13b61b21454eb81cd6a13 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 4 Mar 2007 16:05:44 -0800 Subject: [PATCH] [NET]: Keep sk_backlog near sk_lock sk_backlog is a critical field of struct sock. (known famous words) It is (ab)used in hot paths, in particular in release_sock(), tcp_recvmsg(), tcp_v4_rcv(), sk_receive_skb(). It really makes sense to place it next to sk_lock, because sk_backlog is only used after sk_lock locked (and thus memory cache line in L1 cache). This should reduce cache misses and sk_lock acquisition time. (In theory, we could only move the head pointer near sk_lock, and leaving tail far away, because 'tail' is normally not so hot, but keep it simple :) ) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/sock.h | 18 +++++++++--------- net/core/sock.c | 2 +- 2 files changed, 10 insertions(+), 10 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 2c7d60ca35..a3366c3c83 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -202,6 +202,15 @@ struct sock { unsigned short sk_type; int sk_rcvbuf; socket_lock_t sk_lock; + /* + * The backlog queue is special, it is always used with + * the per-socket spinlock held and requires low latency + * access. Therefore we special case it's implementation. + */ + struct { + struct sk_buff *head; + struct sk_buff *tail; + } sk_backlog; wait_queue_head_t *sk_sleep; struct dst_entry *sk_dst_cache; struct xfrm_policy *sk_policy[2]; @@ -221,15 +230,6 @@ struct sock { int sk_rcvlowat; unsigned long sk_flags; unsigned long sk_lingertime; - /* - * The backlog queue is special, it is always used with - * the per-socket spinlock held and requires low latency - * access. Therefore we special case it's implementation. - */ - struct { - struct sk_buff *head; - struct sk_buff *tail; - } sk_backlog; struct sk_buff_head sk_error_queue; struct proto *sk_prot_creator; rwlock_t sk_callback_lock; diff --git a/net/core/sock.c b/net/core/sock.c index 27c4f62382..6d35d5775b 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -904,6 +904,7 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority) sk_node_init(&newsk->sk_node); sock_lock_init(newsk); bh_lock_sock(newsk); + newsk->sk_backlog.head = newsk->sk_backlog.tail = NULL; atomic_set(&newsk->sk_rmem_alloc, 0); atomic_set(&newsk->sk_wmem_alloc, 0); @@ -923,7 +924,6 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority) newsk->sk_wmem_queued = 0; newsk->sk_forward_alloc = 0; newsk->sk_send_head = NULL; - newsk->sk_backlog.head = newsk->sk_backlog.tail = NULL; newsk->sk_userlocks = sk->sk_userlocks & ~SOCK_BINDPORT_LOCK; sock_reset_flag(newsk, SOCK_DONE); -- 2.39.5