From 4b0b72f7dd617b13abd1b04c947e15873e011a24 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 28 Apr 2010 14:35:48 -0700 Subject: net: speedup udp receive path Since commit 95766fff ([UDP]: Add memory accounting.), each received packet needs one extra sock_lock()/sock_release() pair. This added latency because of possible backlog handling. Then later, ticket spinlocks added yet another latency source in case of DDOS. This patch introduces lock_sock_bh() and unlock_sock_bh() synchronization primitives, avoiding one atomic operation and backlog processing. skb_free_datagram_locked() uses them instead of full blown lock_sock()/release_sock(). skb is orphaned inside locked section for proper socket memory reclaim, and finally freed outside of it. UDP receive path now take the socket spinlock only once. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/datagram.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'net/core') diff --git a/net/core/datagram.c b/net/core/datagram.c index 5574a5ddf90..95b851f3d71 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -229,9 +229,13 @@ EXPORT_SYMBOL(skb_free_datagram); void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) { - lock_sock(sk); - skb_free_datagram(sk, skb); - release_sock(sk); + lock_sock_bh(sk); + skb_orphan(skb); + sk_mem_reclaim_partial(sk); + unlock_sock_bh(sk); + + /* skb is now orphaned, might be freed outside of locked section */ + consume_skb(skb); } EXPORT_SYMBOL(skb_free_datagram_locked); -- cgit v1.2.3-70-g09d2