Re: [PATCH net-next-2.6 v3] net_sched: SFB flow scheduler

Am 23.02.2011 17:13, schrieb Eric Dumazet:

Le mercredi 23 février 2011 à 07:43 -0800, Stephen Hemminger a écrit :

quoted

On Wed, 23 Feb 2011 16:14:51 +0100
Eric Dumazet [off-list ref] wrote:

quoted

1) SFB default child qdisc is pfifo_fast. It can be changed by another
qdisc but a child qdisc MUST not drop a packet previously queued. This
is because SFB needs to handle a dequeued packet in order to maintain
its virtual queue states. pfifo_head_drop or CHOKe should not be used.

Why not add a flag field to Qdisc_ops and to mark qdisc's that
are (or not) work conserving?

That was my initial idea, but have no idea how to implement it (outside
of fast path, I mean...)

This also doesn't really have anything to do with work-conserving
qdiscs, SFB f.i. is work conserving, but still might drop other
packets. Actually I don't think there's any qdisc besides the
*fifos that can reasonably be used with SFB, so we might as well
only support a built-in qdisc.