diff options
author | Eric Dumazet <edumazet@google.com> | 2018-02-28 14:40:46 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2018-03-01 21:44:28 -0500 |
commit | dcb8c9b4373a583451b1b8a3e916d33de273633d (patch) | |
tree | a77ade8d6e0ba6b56de0f5ea2f868b07d26af178 /net/ipv4/tcp_bbr.c | |
parent | 7797dc41417eb0e03f39fc4356f7635bcdef108e (diff) | |
download | op-kernel-dev-dcb8c9b4373a583451b1b8a3e916d33de273633d.zip op-kernel-dev-dcb8c9b4373a583451b1b8a3e916d33de273633d.tar.gz |
tcp_bbr: better deal with suboptimal GSO (II)
This is second part of dealing with suboptimal device gso parameters.
In first patch (350c9f484bde "tcp_bbr: better deal with suboptimal GSO")
we dealt with devices having low gso_max_segs
Some devices lower gso_max_size from 64KB to 16 KB (r8152 is an example)
In order to probe an optimal cwnd, we want BBR being not sensitive
to whatever GSO constraint a device can have.
This patch removes tso_segs_goal() CC callback in favor of
min_tso_segs() for CC wanting to override sysctl_tcp_min_tso_segs
Next patch will remove bbr->tso_segs_goal since it does not have
to be persistent.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_bbr.c')
-rw-r--r-- | net/ipv4/tcp_bbr.c | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c index a471f69..afc0567 100644 --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -261,23 +261,26 @@ static void bbr_set_pacing_rate(struct sock *sk, u32 bw, int gain) sk->sk_pacing_rate = rate; } -/* Return count of segments we want in the skbs we send, or 0 for default. */ -static u32 bbr_tso_segs_goal(struct sock *sk) +/* override sysctl_tcp_min_tso_segs */ +static u32 bbr_min_tso_segs(struct sock *sk) { - struct bbr *bbr = inet_csk_ca(sk); - - return bbr->tso_segs_goal; + return sk->sk_pacing_rate < (bbr_min_tso_rate >> 3) ? 1 : 2; } static void bbr_set_tso_segs_goal(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct bbr *bbr = inet_csk_ca(sk); - u32 min_segs; + u32 segs, bytes; + + /* Sort of tcp_tso_autosize() but ignoring + * driver provided sk_gso_max_size. + */ + bytes = min_t(u32, sk->sk_pacing_rate >> sk->sk_pacing_shift, + GSO_MAX_SIZE - 1 - MAX_TCP_HEADER); + segs = max_t(u32, bytes / tp->mss_cache, bbr_min_tso_segs(sk)); - min_segs = sk->sk_pacing_rate < (bbr_min_tso_rate >> 3) ? 1 : 2; - bbr->tso_segs_goal = min(tcp_tso_autosize(sk, tp->mss_cache, min_segs), - 0x7FU); + bbr->tso_segs_goal = min(segs, 0x7FU); } /* Save "last known good" cwnd so we can restore it after losses or PROBE_RTT */ @@ -936,7 +939,7 @@ static struct tcp_congestion_ops tcp_bbr_cong_ops __read_mostly = { .undo_cwnd = bbr_undo_cwnd, .cwnd_event = bbr_cwnd_event, .ssthresh = bbr_ssthresh, - .tso_segs_goal = bbr_tso_segs_goal, + .min_tso_segs = bbr_min_tso_segs, .get_info = bbr_get_info, .set_state = bbr_set_state, }; |