On Wed, 24 Apr 2002, Varun Varma wrote:
> Amit,
>
> Check out the function dev_queue_xmit in net/core/dev.c. If there isn't
> a queuing discipline attatched to a network device, the packets are not
> queued anywhere, but sent to the device directly.
>
> Regards,
> -Varun
Thanks Varun. I figured this one out yesterday after a complete walk
through of net_bh(), qdisc_run_queues(), qdisc_restart() and
dev_queue_xmit()
Now my only question is:
What happens in case of a device to which none of the well-known qdiscs
(cbq, sfq, wrr etc.) is attached? In that case, the device is 'stuck' with
the noop_qdisc which it gets during its registration -
register_netdevice(), right?
And the enqueue function for the noop_qdisc is noop_enqueue() which just
frees the skb! So where is the actual packet kicked out from?
TIA.
ciao,
Amit
> On Tue, Apr 23, 2002 at 11:18:26PM -0500, Amit Kucheria spoke out thus:
> > Hi,
> >
> > Where are packets queued for a network device?
> >
> > I see 3 members in 'struct device' called qdisc, qdisc_sleeping &
> > qdisc_list which are initialized to noop_qdisc, noop_qdisc and NULL
> > respectively when calling register_netdevice().
> >
> > So how & where are incoming/outgoing packets queued then?
--
I'm an angel!!! Honest!
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Amit Kucheria
EECS Grad. Research Assistant
University of Kansas @ Lawrence
(R)+1-(785)-830 8521 ||| (O)+1-(785)-864 7774
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