[ovs-dev] Open vSwitch Design

[Eric Dumazet]

Le vendredi 25 novembre 2011 à 01:25 -0500, David Miller a écrit :
> From: Eric Dumazet <eric.dumazet at gmail.com>
> Date: Fri, 25 Nov 2011 07:18:03 +0100
> 
> > Le jeudi 24 novembre 2011 à 21:20 -0800, Stephen Hemminger a écrit :
> > 
> >> The problem is that there are two flow classifiers, one in OpenVswitch
> >> in the kernel, and the other in the user space flow manager. I think the
> >> issue is that the two have different code.
> > 
> > We have kind of same duplication in kernel already :)
> > 
> > __skb_get_rxhash() and net/sched/cls_flow.c contain roughly the same
> > logic...
> > 
> > Maybe its time to factorize the thing, eventually use it in a third
> > component (Open vSwitch...)
> 
> Yes.

A third reason to do that anyway is that net/sched/sch_sfb.c should use
__skb_get_rxhash() providing the perturbation itself, and not use the
standard (hashrnd) one ).

Right now, if two flows share same rxhash, the double SFB hash will also
share the same final hash.

(This point was mentioned by Florian Westphal)