tcp: tcp_tso_autosize() minimum is one packet

By making sure sk->sk_gso_max_segs minimal value is one,
and sysctl_tcp_min_tso_segs minimal value is one as well,
tcp_tso_autosize() will return a non zero value.

We can then revert 843925f33f
("tcp: Do not apply TSO segment limit to non-TSO packets")
and save few cpu cycles in fast path.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-05-26 08:55:28 -07:00 committed by David S. Miller
parent 095dc8e0c3
commit d6a4e26afb
3 changed files with 7 additions and 4 deletions

View File

@ -1581,6 +1581,8 @@ EXPORT_SYMBOL_GPL(sk_clone_lock);
void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
{
u32 max_segs = 1;
__sk_dst_set(sk, dst);
sk->sk_route_caps = dst->dev->features;
if (sk->sk_route_caps & NETIF_F_GSO)
@ -1592,9 +1594,10 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
} else {
sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
sk->sk_gso_max_size = dst->dev->gso_max_size;
sk->sk_gso_max_segs = dst->dev->gso_max_segs;
max_segs = max_t(u32, dst->dev->gso_max_segs, 1);
}
}
sk->sk_gso_max_segs = max_segs;
}
EXPORT_SYMBOL_GPL(sk_setup_caps);

View File

@ -702,7 +702,7 @@ static struct ctl_table ipv4_table[] = {
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra1 = &one,
.extra2 = &gso_max_segs,
},
{

View File

@ -2088,7 +2088,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now)))
break;
if (tso_segs == 1 || !max_segs) {
if (tso_segs == 1) {
if (unlikely(!tcp_nagle_test(tp, skb, mss_now,
(tcp_skb_is_last(sk, skb) ?
nonagle : TCP_NAGLE_PUSH))))
@ -2101,7 +2101,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
}
limit = mss_now;
if (tso_segs > 1 && max_segs && !tcp_urg_mode(tp))
if (tso_segs > 1 && !tcp_urg_mode(tp))
limit = tcp_mss_split_point(sk, skb, mss_now,
min_t(unsigned int,
cwnd_quota,