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authorEric Dumazet <eric.dumazet@gmail.com>2010-04-27 18:13:20 -0400
committerDavid S. Miller <davem@davemloft.net>2010-04-27 18:13:20 -0400
commitc377411f2494a931ff7facdbb3a6839b1266bcf6 (patch)
tree6846cdcec913f50839e3916856f78f7e059ff5fb /net/ipv6/udp.c
parent6e7676c1a76aed6e957611d8d7a9e5592e23aeba (diff)
net: sk_add_backlog() take rmem_alloc into account
Current socket backlog limit is not enough to really stop DDOS attacks, because user thread spend many time to process a full backlog each round, and user might crazy spin on socket lock. We should add backlog size and receive_queue size (aka rmem_alloc) to pace writers, and let user run without being slow down too much. Introduce a sk_rcvqueues_full() helper, to avoid taking socket lock in stress situations. Under huge stress from a multiqueue/RPS enabled NIC, a single flow udp receiver can now process ~200.000 pps (instead of ~100 pps before the patch) on a 8 core machine. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/udp.c')
-rw-r--r--net/ipv6/udp.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 2850e35cee3d..3ead20ad9d07 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -584,6 +584,10 @@ static void flush_stack(struct sock **stack, unsigned int count,
584 584
585 sk = stack[i]; 585 sk = stack[i];
586 if (skb1) { 586 if (skb1) {
587 if (sk_rcvqueues_full(sk, skb)) {
588 kfree_skb(skb1);
589 goto drop;
590 }
587 bh_lock_sock(sk); 591 bh_lock_sock(sk);
588 if (!sock_owned_by_user(sk)) 592 if (!sock_owned_by_user(sk))
589 udpv6_queue_rcv_skb(sk, skb1); 593 udpv6_queue_rcv_skb(sk, skb1);
@@ -759,6 +763,10 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
759 763
760 /* deliver */ 764 /* deliver */
761 765
766 if (sk_rcvqueues_full(sk, skb)) {
767 sock_put(sk);
768 goto discard;
769 }
762 bh_lock_sock(sk); 770 bh_lock_sock(sk);
763 if (!sock_owned_by_user(sk)) 771 if (!sock_owned_by_user(sk))
764 udpv6_queue_rcv_skb(sk, skb); 772 udpv6_queue_rcv_skb(sk, skb);