[ovs-dev] [PATCH v2.0] Non-Datapath MPLS actions and matches

[Jesse Gross]

On Thu, Sep 27, 2012 at 9:26 AM, Ben Pfaff <blp at nicira.com> wrote:
> On Wed, Sep 26, 2012 at 04:13:41PM +0900, Simon Horman wrote:
>> This patch provides an implementation of the non-datapath portions
>> of MPLS matches and actions.
>>
>> This patch is based on top of Ben Pfaff's series,
>> "set-field action support"
>>
>> Cc: Isaku Yamahata <yamahata at valinux.co.jp>
>> Cc: Ravi K <rkerur at gmail.com>
>
> I think Ravi's full last name is "Kerur".
>
>> Signed-off-by: Simon Horman <horms at verge.net.au>
>
> Jesse, do you have any concerns about this?  I haven't read past the
> diffstat yet.  But if it seems like a reasonable intermediate approach
> then I'm happy to review it.

I don't think there is inherently anything wrong in starting with a
userspace-only approach.  I have a couple of specific concerns based
on briefly skimming the patch:
 * It seems like this is really the userspace half of the code which
assumes that the kernel portions will still be doing the work on the
actual packet flows.  If that's the case then I don't think that
userspace support can go in independently.  Otherwise, userspace
should really be self-contained and setup slow-path flows to do the
work itself.
 * If it is truly userspace only, the handling of multiple levels of
tags seems a little incomplete since we actually have the full packet.
 If this is supposed to be a quick stepping stone to kernel support
that seems less important since we will no longer have complete packet
access.

So it basically comes down to what the short term plans are.  There's
also Leo's patch (which I haven't looked at) that I can post if there
are plans to do kernel support.