From 1b3878ca1551f3baab2c408d1e703b5ef785a1b2 Mon Sep 17 00:00:00 2001 From: Neal Cardwell Date: Mon, 19 Sep 2016 23:39:18 -0400 Subject: [PATCH] tcp: export tcp_tso_autosize() and parameterize minimum number of TSO segments To allow congestion control modules to use the default TSO auto-sizing algorithm as one of the ingredients in their own decision about TSO sizing: 1) Export tcp_tso_autosize() so that CC modules can use it. 2) Change tcp_tso_autosize() to allow callers to specify a minimum number of segments per TSO skb, in case the congestion control module has a different notion of the best floor for TSO skbs for the connection right now. For very low-rate paths or policed connections it can be appropriate to use smaller TSO skbs. Signed-off-by: Van Jacobson Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Nandita Dukkipati Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller --- include/net/tcp.h | 2 ++ net/ipv4/tcp_output.c | 9 ++++++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index f8f581fd05f5..349204130d84 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -533,6 +533,8 @@ __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mss); #endif /* tcp_output.c */ +u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now, + int min_tso_segs); void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, int nonagle); bool tcp_may_send_now(struct sock *sk); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 01379567a732..0bf3d481fa85 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1549,7 +1549,8 @@ static bool tcp_nagle_check(bool partial, const struct tcp_sock *tp, /* Return how many segs we'd like on a TSO packet, * to send one TSO packet per ms */ -static u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now) +u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now, + int min_tso_segs) { u32 bytes, segs; @@ -1561,10 +1562,11 @@ static u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now) * This preserves ACK clocking and is consistent * with tcp_tso_should_defer() heuristic. */ - segs = max_t(u32, bytes / mss_now, sysctl_tcp_min_tso_segs); + segs = max_t(u32, bytes / mss_now, min_tso_segs); return min_t(u32, segs, sk->sk_gso_max_segs); } +EXPORT_SYMBOL(tcp_tso_autosize); /* Return the number of segments we want in the skb we are transmitting. * See if congestion control module wants to decide; otherwise, autosize. @@ -1574,7 +1576,8 @@ static u32 tcp_tso_segs(struct sock *sk, unsigned int mss_now) const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; u32 tso_segs = ca_ops->tso_segs_goal ? ca_ops->tso_segs_goal(sk) : 0; - return tso_segs ? : tcp_tso_autosize(sk, mss_now); + return tso_segs ? : + tcp_tso_autosize(sk, mss_now, sysctl_tcp_min_tso_segs); } /* Returns the portion of skb which can be sent right away */ -- 2.20.1