diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-28 00:13:20 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-04-28 00:13:20 +0200 |
| commit | c377411f2494a931ff7facdbb3a6839b1266bcf6 (patch) | |
| tree | 6846cdcec913f50839e3916856f78f7e059ff5fb /include | |
| parent | net: batch skb dequeueing from softnet input_pkt_queue (diff) | |
| download | linux-c377411f2494a931ff7facdbb3a6839b1266bcf6.tar.xz linux-c377411f2494a931ff7facdbb3a6839b1266bcf6.zip | |
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 'include')
| -rw-r--r-- | include/net/sock.h | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 07822280d953..cf12b1e61fa6 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -256,7 +256,6 @@ struct sock { struct sk_buff *head; struct sk_buff *tail; int len; - int limit; } sk_backlog; wait_queue_head_t *sk_sleep; struct dst_entry *sk_dst_cache; @@ -608,10 +607,20 @@ static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb) skb->next = NULL; } +/* + * Take into account size of receive queue and backlog queue + */ +static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb) +{ + unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc); + + return qsize + skb->truesize > sk->sk_rcvbuf; +} + /* The per-socket spinlock must be held here. */ static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb) { - if (sk->sk_backlog.len >= max(sk->sk_backlog.limit, sk->sk_rcvbuf << 1)) + if (sk_rcvqueues_full(sk, skb)) return -ENOBUFS; __sk_add_backlog(sk, skb); |