Re: [PATCH net] tcp: Do not underestimate rwnd_limited
From: Soheil Hassas Yeganeh <hidden>
Date: 2018-12-05 22:28:45
On Wed, Dec 5, 2018 at 5:24 PM Eric Dumazet [off-list ref] wrote:
If available rwnd is too small, tcp_tso_should_defer()
can decide it is worth waiting before splitting a TSO packet.
This really means we are rwnd limited.
Fixes: 5615f88614a4 ("tcp: instrument how long TCP is limited by receive window")
Signed-off-by: Eric Dumazet <edumazet@google.com>Acked-by: Soheil Hassas Yeganeh <redacted> Excellent catch! Thank you for the fix, Eric!
quoted hunk ↗ jump to hunk
--- net/ipv4/tcp_output.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 68b5326f73212ffe7111dd0f91e0a1246fb0ae25..3186902347584090256467d8679320666aa0257e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c@@ -2356,8 +2356,11 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, } else { if (!push_one && tcp_tso_should_defer(sk, skb, &is_cwnd_limited, - max_segs)) + max_segs)) { + if (!is_cwnd_limited) + is_rwnd_limited = true; break; + } } limit = mss_now; --2.20.0.rc2.403.gdbc3b29805-goog