On Tue, Jun 7, 2016 at 4:01 PM, David Miller [off-list ref] wrote:

From: John Crispin <john@phrozen.org>
Date: Mon, 6 Jun 2016 08:43:13 +0200

quoted

i think one solution would be to add some code to have 2 devices share
the same dql instance. would that be an acceptable solution ?

You still need to address the issue of synchronization.

dql purposefully doesn't use locking, always because a higher level
object (in this case the netdev TX queue) it is contained within
provides the synchronization.

That breaks apart once you share the dql between two netdevs, as you
are proposing here.  You'll have to add locking, which is expensive.

That's why I'm trying to encourage you to think out of the box and
find some way to solve the issue without having to access shared
state shared between multiple devices.

I think you guys mean mean BQL not DQL :-)

If two netdevs share the same DMA ring then is using two netdevs the
right approach. Seems like this would have other consequences beyond
BQL...

Tom

Thanks.