[ovs-dev] Datapath Merge Revisited

Jesse Gross jesse at nicira.com
Tue Nov 2 20:39:44 UTC 2010

On Tue, Nov 2, 2010 at 5:41 AM, Simon Horman <horms at verge.net.au> wrote:
> Hi,
> are there any outstanding issues in the datapath that
> would prevent me from preparing some patches against
> (pre 2.6.38) net-next-2.6 once it opens and submitting
> them here and to netdev for review?

Unfortunately some of the Netlink changes got bogged down aren't in
yet due to time constraints.  Beyond that and the 2.6.37 related
things that I mentioned in the other message, there is one additional
thing that has come up.

A few months ago, another project tried to merge upstream and Dave
Miller commented[1] on their implementation of a hash table library.
There's something fairly similar in the Open vSwitch datapath.  In
addition to his (valid) concerns, the current OVS flow table is a
source of bugs that are difficult to eliminate as is.  This is because
deleting an entry requires allocating memory to enable RCU and those
allocations can potentially fail.  While deletions can return an error
code, it's often not clear what the caller should do with it and we
can end up in a inconsistent state.

It would be really nice if we can address this problem now.  We'll
almost certainly need to deal with it before the merge.

[1] http://permalink.gmane.org/gmane.linux.network/172955

More information about the dev mailing list