[ovs-dev] [PATCH v5 REPOST] ofproto: Honour Table Mod settings for table-miss handling

Ben Pfaff blp at nicira.com
Wed Feb 12 16:22:02 UTC 2014


On Wed, Feb 12, 2014 at 05:24:30PM +0900, Simon Horman wrote:
> On Mon, Feb 03, 2014 at 05:12:12PM -0800, Ben Pfaff wrote:
> > On Wed, Jan 29, 2014 at 12:53:03PM +0900, Simon Horman wrote:
> > > This reworks lookup of rules for both table 0 and table action translation.
> > > The result is that Table Mod settings, which can alter the miss-behaviour
> > > of tables, including table 0, on a per-table basis may be honoured.
> > > 
> > > Previous patches proposed by myself which build on earlier merged patches
> > > by Andy Zhou implement the ofproto side of Table Mod. So with this patch
> > > the feature should be complete.
> > > 
> > > Neither this patch, nor any other patches it builds on, alter the default
> > > behaviour of Open vSwitch. And in particular the OpenFlow1.1 behaviour is
> > > the default regardless of which OpenFlow version is negotiated between the
> > > switch and the controller.
> > > 
> > > An implementation detail, which lends itself to future work, is the
> > > handling of OFPTC_TABLE_MISS_CONTINUE. If a table has this behaviour set by
> > > Table Mod and a miss occurs then a loop is created, skipping to the next
> > > table. It is quite easy to create a situation where this loop covers ~255
> > > tables which is very expensive as the lookup for each table involves taking
> > > locks, amongst other things.
> > > 
> > > Cc: Andy Zhou <azhou at nicira.com>
> > > Signed-off-by: Simon Horman <horms at verge.net.au>
> 
> Sorry for missing this and posting v6.

It happens.

> > This commit reads more naturally to me when we fold in the following.
> > (I haven't tested it yet to make sure the tests still pass, but I
> > don't intend this to change behavior.)
> 
> Thanks, I'll look at squashing it (or some variant of it that works)
> into my next post.

Thanks for this and the rest of the responses.  I look forward to v7.



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