[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 <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/sock.c b/net/core/sock.c
index 27c4f62..6d35d57 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -904,6 +904,7 @@
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 @@
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);
