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authorEric Dumazet <eric.dumazet@gmail.com>2010-04-28 14:35:48 -0700
committerDavid S. Miller <davem@davemloft.net>2010-04-28 14:35:48 -0700
commit4b0b72f7dd617b13abd1b04c947e15873e011a24 (patch)
tree16fc7bc990fa47cccb62bdb34cb23bd3c26b7a50
parentcfc1fbb079b265bf69d4ceba590a2e2c1a1cde33 (diff)
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 <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/sock.h10
-rw-r--r--net/core/datagram.c10
-rw-r--r--net/ipv4/udp.c12
-rw-r--r--net/ipv6/udp.c4
4 files changed, 25 insertions, 11 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index cf12b1e61fa..d361c7769fe 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1021,6 +1021,16 @@ extern void release_sock(struct sock *sk);
SINGLE_DEPTH_NESTING)
#define bh_unlock_sock(__sk) spin_unlock(&((__sk)->sk_lock.slock))
+static inline void lock_sock_bh(struct sock *sk)
+{
+ spin_lock_bh(&sk->sk_lock.slock);
+}
+
+static inline void unlock_sock_bh(struct sock *sk)
+{
+ spin_unlock_bh(&sk->sk_lock.slock);
+}
+
extern struct sock *sk_alloc(struct net *net, int family,
gfp_t priority,
struct proto *prot);
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);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 63eb56b2d87..1f86965ba7d 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1062,10 +1062,10 @@ static unsigned int first_packet_length(struct sock *sk)
spin_unlock_bh(&rcvq->lock);
if (!skb_queue_empty(&list_kill)) {
- lock_sock(sk);
+ lock_sock_bh(sk);
__skb_queue_purge(&list_kill);
sk_mem_reclaim_partial(sk);
- release_sock(sk);
+ unlock_sock_bh(sk);
}
return res;
}
@@ -1196,10 +1196,10 @@ out:
return err;
csum_copy_err:
- lock_sock(sk);
+ lock_sock_bh(sk);
if (!skb_kill_datagram(sk, skb, flags))
UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
- release_sock(sk);
+ unlock_sock_bh(sk);
if (noblock)
return -EAGAIN;
@@ -1624,9 +1624,9 @@ int udp_rcv(struct sk_buff *skb)
void udp_destroy_sock(struct sock *sk)
{
- lock_sock(sk);
+ lock_sock_bh(sk);
udp_flush_pending_frames(sk);
- release_sock(sk);
+ unlock_sock_bh(sk);
}
/*
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 3ead20ad9d0..91c60f0090a 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -424,7 +424,7 @@ out:
return err;
csum_copy_err:
- lock_sock(sk);
+ lock_sock_bh(sk);
if (!skb_kill_datagram(sk, skb, flags)) {
if (is_udp4)
UDP_INC_STATS_USER(sock_net(sk),
@@ -433,7 +433,7 @@ csum_copy_err:
UDP6_INC_STATS_USER(sock_net(sk),
UDP_MIB_INERRORS, is_udplite);
}
- release_sock(sk);
+ unlock_sock_bh(sk);
if (flags & MSG_DONTWAIT)
return -EAGAIN;