diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-27 15:13:20 -0700 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2012-03-14 10:58:05 -0400 |
| commit | a31deff4d20232dfc8370f0320e8b0925f5655b0 (patch) | |
| tree | 4e41be5e40ec6982ee4b6f8d11ec6a9b6bd56998 /include/net | |
| parent | 56defd4dc08f361bdf74c6cb457aebb1ccf442d1 (diff) | |
net: sk_add_backlog() take rmem_alloc into account
commit c377411f2494a931ff7facdbb3a6839b1266bcf6 upstream.
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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'include/net')
| -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 721c7b3a7a7..b365fc2597c 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -255,7 +255,6 @@ 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; @@ -604,10 +603,20 @@ 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); |