From: Tommy Christensen <tommy.christensen@tpack.net>
To: Denis Vlasenko <vda@ilport.com.ua>
Cc: "David S. Miller" <davem@davemloft.net>,
jgarzik@pobox.com, linux-kernel@vger.kernel.org,
linux-net@vger.kernel.org
Subject: Re: 2.6.11-rc5 and 2.6.12: cannot transmit anything - more info
Date: Thu, 04 Aug 2005 22:45:33 +0200 [thread overview]
Message-ID: <42F27E6D.2030200@tpack.net> (raw)
In-Reply-To: <200508030947.01901.vda@ilport.com.ua>
Denis Vlasenko wrote:
> Hi,
>
> As reported earlier, sometimes my home box don't want
> to send anything.
>
> # ip r
> 1.1.5.5 dev tun0 proto kernel scope link src 1.1.5.6
> 1.1.4.0/24 dev if proto kernel scope link src 1.1.4.6
> default via 1.1.5.5 dev tun0
> # ping 1.1.4.1 -i 0.01
> 2005-08-02_19:12:18.19551 kern.info: qdisc_restart: start, q->dequeue=c03e8662
> 2005-08-02_19:12:19.19536 kern.info: qdisc_restart: start, q->dequeue=c03e8662
>
> System.map:
> c03e8662 t noop_dequeue
>
> I guess this explains why I do not see calls to pfifo_fast_dequeue! :)
> But how come my interface is using noop queue, is a mystery to me.
Because link is down. Or at least the kernel thinks so.
> # ip l
> 1: if: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
> link/ether 00:0a:e6:7c:dd:79 brd ff:ff:ff:ff:ff:ff
> 2: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
> link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
> 17: tun0: <POINTOPOINT,MULTICAST,NOARP,UP> mtu 1464 qdisc pfifo_fast qlen 100
> link/[65534]
>
> As you can see, ip l reports that iface 'if' uses pfifo_fast, not noop...
Yeah, a bit confusing. pfifo_fast is the *configured* qdisc, but in this
case it is not the *active* qdisc. The qdisc is set to noop when carrier
is lost.
> Any ideas?
Try tracking the calls to netif_carrier_on/off.
-Tommy
next prev parent reply other threads:[~2005-08-04 20:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-03 6:47 2.6.11-rc5 and 2.6.12: cannot transmit anything - more info Denis Vlasenko
2005-08-04 20:45 ` Tommy Christensen [this message]
2005-08-07 13:51 ` Denis Vlasenko
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