d9969b8c58
Pulled from: 4d43b58a4f
Compile-tested on: x86_64
Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>
139 lines
4.9 KiB
Diff
139 lines
4.9 KiB
Diff
From 1fbad3e6fe0e01f071941a5689fb5f72428ca31a Mon Sep 17 00:00:00 2001
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From: Eric Dumazet <edumazet@google.com>
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Date: Wed, 28 Feb 2018 14:40:46 -0800
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Subject: [PATCH] tcp_bbr: better deal with suboptimal GSO (II)
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This is second part of dealing with suboptimal device gso parameters.
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In first patch (350c9f484bde "tcp_bbr: better deal with suboptimal GSO")
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we dealt with devices having low gso_max_segs
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Some devices lower gso_max_size from 64KB to 16 KB (r8152 is an example)
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In order to probe an optimal cwnd, we want BBR being not sensitive
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to whatever GSO constraint a device can have.
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This patch removes tso_segs_goal() CC callback in favor of
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min_tso_segs() for CC wanting to override sysctl_tcp_min_tso_segs
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Next patch will remove bbr->tso_segs_goal since it does not have
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to be persistent.
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Signed-off-by: Eric Dumazet <edumazet@google.com>
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Acked-by: Neal Cardwell <ncardwell@google.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: UtsavisGreat <utsavbalar1231@gmail.com>
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---
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include/net/tcp.h | 6 ++----
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net/ipv4/tcp_bbr.c | 23 +++++++++++++----------
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net/ipv4/tcp_output.c | 15 ++++++++-------
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3 files changed, 23 insertions(+), 21 deletions(-)
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--- a/include/net/tcp.h
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+++ b/include/net/tcp.h
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@@ -551,8 +551,6 @@ __u32 cookie_v6_init_sequence(const stru
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#endif
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/* tcp_output.c */
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-u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now,
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- int min_tso_segs);
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void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
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int nonagle);
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int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs);
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@@ -1025,8 +1023,8 @@ struct tcp_congestion_ops {
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u32 (*undo_cwnd)(struct sock *sk);
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/* hook for packet ack accounting (optional) */
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void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample);
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- /* suggest number of segments for each skb to transmit (optional) */
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- u32 (*tso_segs_goal)(struct sock *sk);
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+ /* override sysctl_tcp_min_tso_segs */
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+ u32 (*min_tso_segs)(struct sock *sk);
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/* returns the multiplier used in tcp_sndbuf_expand (optional) */
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u32 (*sndbuf_expand)(struct sock *sk);
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/* call when packets are delivered to update cwnd and pacing rate,
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--- a/net/ipv4/tcp_bbr.c
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+++ b/net/ipv4/tcp_bbr.c
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@@ -261,23 +261,26 @@ static void bbr_set_pacing_rate(struct s
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sk->sk_pacing_rate = rate;
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}
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-/* Return count of segments we want in the skbs we send, or 0 for default. */
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-static u32 bbr_tso_segs_goal(struct sock *sk)
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+/* override sysctl_tcp_min_tso_segs */
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+static u32 bbr_min_tso_segs(struct sock *sk)
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{
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- struct bbr *bbr = inet_csk_ca(sk);
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-
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- return bbr->tso_segs_goal;
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+ return sk->sk_pacing_rate < (bbr_min_tso_rate >> 3) ? 1 : 2;
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}
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static void bbr_set_tso_segs_goal(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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struct bbr *bbr = inet_csk_ca(sk);
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- u32 min_segs;
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+ u32 segs, bytes;
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+
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+ /* Sort of tcp_tso_autosize() but ignoring
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+ * driver provided sk_gso_max_size.
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+ */
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+ bytes = min_t(u32, sk->sk_pacing_rate >> sk->sk_pacing_shift,
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+ GSO_MAX_SIZE - 1 - MAX_TCP_HEADER);
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+ segs = max_t(u32, bytes / tp->mss_cache, bbr_min_tso_segs(sk));
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- min_segs = sk->sk_pacing_rate < (bbr_min_tso_rate >> 3) ? 1 : 2;
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- bbr->tso_segs_goal = min(tcp_tso_autosize(sk, tp->mss_cache, min_segs),
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- 0x7FU);
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+ bbr->tso_segs_goal = min(segs, 0x7FU);
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}
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/* Save "last known good" cwnd so we can restore it after losses or PROBE_RTT */
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@@ -941,7 +944,7 @@ static struct tcp_congestion_ops tcp_bbr
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.undo_cwnd = bbr_undo_cwnd,
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.cwnd_event = bbr_cwnd_event,
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.ssthresh = bbr_ssthresh,
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- .tso_segs_goal = bbr_tso_segs_goal,
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+ .min_tso_segs = bbr_min_tso_segs,
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.get_info = bbr_get_info,
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.set_state = bbr_set_state,
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};
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--- a/net/ipv4/tcp_output.c
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+++ b/net/ipv4/tcp_output.c
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@@ -1695,8 +1695,8 @@ static bool tcp_nagle_check(bool partial
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/* Return how many segs we'd like on a TSO packet,
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* to send one TSO packet per ms
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*/
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-u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now,
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- int min_tso_segs)
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+static u32 tcp_tso_autosize(const struct sock *sk, unsigned int mss_now,
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+ int min_tso_segs)
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{
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u32 bytes, segs;
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@@ -1712,7 +1712,6 @@ u32 tcp_tso_autosize(const struct sock *
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return segs;
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}
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-EXPORT_SYMBOL(tcp_tso_autosize);
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/* Return the number of segments we want in the skb we are transmitting.
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* See if congestion control module wants to decide; otherwise, autosize.
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@@ -1720,11 +1719,13 @@ EXPORT_SYMBOL(tcp_tso_autosize);
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static u32 tcp_tso_segs(struct sock *sk, unsigned int mss_now)
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{
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const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
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- u32 tso_segs = ca_ops->tso_segs_goal ? ca_ops->tso_segs_goal(sk) : 0;
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+ u32 min_tso, tso_segs;
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- if (!tso_segs)
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- tso_segs = tcp_tso_autosize(sk, mss_now,
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- sysctl_tcp_min_tso_segs);
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+ min_tso = ca_ops->min_tso_segs ?
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+ ca_ops->min_tso_segs(sk) :
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+ sysctl_tcp_min_tso_segs;
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+
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+ tso_segs = tcp_tso_autosize(sk, mss_now, min_tso);
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return min_t(u32, tso_segs, sk->sk_gso_max_segs);
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}
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