From: David Miller <davem@davemloft.net>
To: yangpc@wangsu.com
Cc: edumazet@google.com, kuznet@ms2.inr.ac.ru,
yoshfuji@linux-ipv6.org, ast@kernel.org, daniel@iogearbox.net,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tcp: fix marked lost packets not being retransmitted
Date: Wed, 15 Jan 2020 13:35:42 -0800 (PST) [thread overview]
Message-ID: <20200115.133542.149188857628032129.davem@davemloft.net> (raw)
In-Reply-To: <1578993820-2114-1-git-send-email-yangpc@wangsu.com>
From: Pengcheng Yang <yangpc@wangsu.com>
Date: Tue, 14 Jan 2020 17:23:40 +0800
> When the packet pointed to by retransmit_skb_hint is unlinked by ACK,
> retransmit_skb_hint will be set to NULL in tcp_clean_rtx_queue().
> If packet loss is detected at this time, retransmit_skb_hint will be set
> to point to the current packet loss in tcp_verify_retransmit_hint(),
> then the packets that were previously marked lost but not retransmitted
> due to the restriction of cwnd will be skipped and cannot be
> retransmitted.
>
> To fix this, when retransmit_skb_hint is NULL, retransmit_skb_hint can
> be reset only after all marked lost packets are retransmitted
> (retrans_out >= lost_out), otherwise we need to traverse from
> tcp_rtx_queue_head in tcp_xmit_retransmit_queue().
>
> Packetdrill to demonstrate:
...
> Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
Applied, thank you.
prev parent reply other threads:[~2020-01-15 21:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 9:23 [PATCH] tcp: fix marked lost packets not being retransmitted Pengcheng Yang
2020-01-14 15:26 ` Neal Cardwell
2020-01-14 16:05 ` Eric Dumazet
2020-01-14 18:39 ` Yuchung Cheng
2020-01-15 6:58 ` Pengcheng Yang
2020-01-15 21:35 ` David Miller [this message]
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