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From: Jamal Hadi Salim <jhs@mojatatu•com>
To: Cong Wang <xiyou.wangcong@gmail•com>,
	Eric Dumazet <eric.dumazet@gmail•com>
Cc: 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 06:49:26 -0400	[thread overview]
Message-ID: <57555536.1090801@mojatatu.com> (raw)
In-Reply-To: <CAM_iQpXMwT20nhWW4Pd2yy6nkeXkSNdxV9wAEGzGd22PcyePmg@mail.gmail.com>

On 16-06-05 07:30 PM, Cong Wang wrote:

> Potentially all of the following:
>
> net/sched/sch_choke.c:  return NET_XMIT_CN;
> net/sched/sch_fifo.c:   return NET_XMIT_CN;
> net/sched/sch_generic.c:        return NET_XMIT_CN;
> net/sched/sch_gred.c:   return NET_XMIT_CN;
> net/sched/sch_hhf.c:            return NET_XMIT_CN;
> net/sched/sch_red.c:    return NET_XMIT_CN;
> net/sched/sch_sfb.c:    return NET_XMIT_CN;
> net/sched/sch_sfq.c:            return NET_XMIT_CN;
>

As long as we are not loosing the stat that the packet
is dropped. Some qdiscs have a counter which indicates
congestion drops(look at RED variants of early drops);
maybe codel needs one. The parent also must account for
childs drops.
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.

cheers,
jamal

  reply	other threads:[~2016-06-06 10:49 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 [this message]
2016-06-06 11:42               ` Florian Westphal
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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