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authorNeal Cardwell <ncardwell@google.com>2016-09-20 06:39:18 +0300
committerDavid S. Miller <davem@davemloft.net>2016-09-21 07:23:00 +0300
commit1b3878ca1551f3baab2c408d1e703b5ef785a1b2 (patch)
treef2560c86746099f8fd8506ee94afff56c6160141
parented6e7268b930e0a9a65d895d368eac79a438d992 (diff)
downloadlinux-1b3878ca1551f3baab2c408d1e703b5ef785a1b2.tar.xz
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 <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/tcp.h2
-rw-r--r--net/ipv4/tcp_output.c9
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 */