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| author |   Eric Dumazet <edumazet@google.com> | 2020-04-30 10:35:41 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2020-04-30 13:24:01 -0700 |
| commit | 2b195850128f5bafde177b12489d9fa27962cc1e (patch) | |
| tree | bbb5e20a0e2c8cb06bb28d316d89b7b821672cdc /net/ipv4/tcp_timer.c | |
| parent | Merge tag 'mlx5-updates-2020-04-30' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux (diff) | |
| download | wireguard-linux-2b195850128f5bafde177b12489d9fa27962cc1e.tar.xz wireguard-linux-2b195850128f5bafde177b12489d9fa27962cc1e.zip | |
tcp: add tp->dup_ack_counter
In commit 86de5921a3d5 ("tcp: defer SACK compression after DupThresh")
I added a TCP_FASTRETRANS_THRESH bias to tp->compressed_ack in order
to enable sack compression only after 3 dupacks.
Since we plan to relax this rule for flows that involve
stacks not requiring this old rule, this patch adds
a distinct tp->dup_ack_counter.
This means the TCP_FASTRETRANS_THRESH value is now used
in a single location that a future patch can adjust:
if (tp->dup_ack_counter < TCP_FASTRETRANS_THRESH) {
tp->dup_ack_counter++;
goto send_now;
}
This patch also introduces tcp_sack_compress_send_ack()
helper to ease following patch comprehension.
This patch refines LINUX_MIB_TCPACKCOMPRESSED to not
count the acks that we had to send if the timer expires
or tcp_sack_compress_send_ack() is sending an ack.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_timer.c')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index c3f26dcd6704..ada046f425d2 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -753,8 +753,14 @@ static enum hrtimer_restart tcp_compressed_ack_kick(struct hrtimer *timer) bh_lock_sock(sk); if (!sock_owned_by_user(sk)) { - if (tp->compressed_ack > TCP_FASTRETRANS_THRESH) + if (tp->compressed_ack) { + /* Since we have to send one ack finally, + * substract one from tp->compressed_ack to keep + * LINUX_MIB_TCPACKCOMPRESSED accurate. + */ + tp->compressed_ack--; tcp_send_ack(sk); + } } else { if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, &sk->sk_tsq_flags)) |