Commit b4e26f5e authored by David S. Miller's avatar David S. Miller

[TCP]: Fix send-side cpu utiliziation regression.

Only put user data purely to pages when doing TSO.

The extra page allocations cause two problems:

1) Add the overhead of the page allocations themselves.
2) Make us do small user copies when we get to the end
   of the TCP socket cache page.

It is still beneficial to purely use pages for TSO,
so we will do it for that case.
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aa93466b
...@@ -756,8 +756,17 @@ static inline int select_size(struct sock *sk, struct tcp_sock *tp) ...@@ -756,8 +756,17 @@ static inline int select_size(struct sock *sk, struct tcp_sock *tp)
{ {
int tmp = tp->mss_cache_std; int tmp = tp->mss_cache_std;
if (sk->sk_route_caps & NETIF_F_SG) if (sk->sk_route_caps & NETIF_F_SG) {
tmp = 0; if (sk->sk_route_caps & NETIF_F_TSO)
tmp = 0;
else {
int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
if (tmp >= pgbreak &&
tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
tmp = pgbreak;
}
}
return tmp; return tmp;
} }
......
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