On Sat, Aug 27, 2016 at 07:37:54AM -0700, Eric Dumazet wrote:
> +bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
> +{
> + u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf;
^^^
...
> + if (!skb->data_len)
> + skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
> +
> + if (unlikely(sk_add_backlog(sk, skb, limit))) {
...
> - } else if (unlikely(sk_add_backlog(sk, skb,
> - sk->sk_rcvbuf + sk->sk_sndbuf))) {
^---- [1]
> - bh_unlock_sock(sk);
> - __NET_INC_STATS(net, LINUX_MIB_TCPBACKLOGDROP);
> + } else if (tcp_add_backlog(sk, skb)) {
Hi Eric, after this patch, do you think we still need to add sk_sndbuf
as a stretching factor to the backlog here?
It was added by [1] and it was justified that the (s)ack packets were
just too big for the rx buf size. Maybe this new patch alone is enough
already, as such packets will have a very small truesize then.
Marcelo
[1] da882c1f2eca ("tcp: sk_add_backlog() is too agressive for TCP")
