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From: Florian Westphal <fw@strlen.de>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Florian Westphal <fw@strlen.de>,
	David Miller <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	Stas Nichiporovich <stasn77@gmail.com>
Subject: Re: [PATCH v2 net] fq_codel: fix NET_XMIT_CN behavior
Date: Mon, 6 Jun 2016 13:42:34 +0200	[thread overview]
Message-ID: <20160606114234.GB7827@breakpoint.cc> (raw)
In-Reply-To: <57555536.1090801@mojatatu.com>

Jamal Hadi Salim <jhs@mojatatu.com> wrote:
> BTW, returning NET_XMIT_CN could be confusing to tcp;
> it does not mean that the packet that we are getting return
> code for was dropped; it could mean _another_ packet in
> the queue was dropped.

Yes, but we currently conceal NET_XMIT_CN from upper layer (tcp)
via the net_xmit_* macros:

#define net_xmit_eval(e)       ((e) == NET_XMIT_CN ? 0 : (e))
#define net_xmit_errno(e)      ((e) != NET_XMIT_CN ? -ENOBUFS : 0)

Might be worth changing this so tcp reduces cwnd in _CN case too.

  reply	other threads:[~2016-06-06 11:42 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-04 17:43 [PATCH net] fq_codel: fix NET_XMIT_CN behavior Eric Dumazet
2016-06-04 19:03 ` [net] " Florian Westphal
2016-06-04 19:40   ` Eric Dumazet
2016-06-04 19:55   ` [PATCH v2 net] " Eric Dumazet
2016-06-05 13:03     ` Jamal Hadi Salim
2016-06-05 20:30     ` Cong Wang
2016-06-05 20:54       ` Eric Dumazet
2016-06-05 20:55         ` Eric Dumazet
2016-06-05 23:30           ` Cong Wang
2016-06-06 10:49             ` Jamal Hadi Salim
2016-06-06 11:42               ` Florian Westphal [this message]
2016-06-06 14:37                 ` Eric Dumazet
2016-06-06 16:18                   ` Florian Westphal
2016-06-10 12:02                     ` Jamal Hadi Salim
2016-06-06 14:29               ` Eric Dumazet
2016-06-07 22:39     ` David Miller

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