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authorEric Dumazet <eric.dumazet@gmail.com>2010-04-27 15:13:20 -0700
committerDavid S. Miller <davem@davemloft.net>2010-04-27 15:13:20 -0700
commitc377411f2494a931ff7facdbb3a6839b1266bcf6 (patch)
tree6846cdcec913f50839e3916856f78f7e059ff5fb /include/net/sock.h
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 'include/net/sock.h')
-rw-r--r--include/net/sock.h13
1 files changed, 11 insertions, 2 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 07822280d95..cf12b1e61fa 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);