Re: [PATCH net-next 0/9] net: bridge: vlan: broadcast fwding path optimizations

[Ido Schimmel <idosch@nvidia.com>]

On Fri, Sep 18, 2026 at 06:29:41PM +0300, Nikolay Aleksandrov wrote:
> Hi,
> This patch-set is the first step to removing unnecessary VLAN hash lookups
> from the bridge fast-path and also provides additional broadcast path
> optimization by considering only the port-VLANs that actually participate
> in the VLAN instead of all bridge ports. Combined these changes bring
> considerable improvements[1] and open the path to do the same for the most
> common fdb forwarding path. As expected the pathological cases have the
> largest gain, e.g. if we have 1 client / VM facing port and 1 upstream port
> only participating in a VLAN with many other bridge ports, we consider only
> those 2 when broadcasting in that VLAN.
> 
> For up to 8 ports we only use the port-VLAN list as the array doesn't make
> much of a difference and is unnecessary. Note that the array is rebuilt on
> every member add or delete when >8 members, I tested that and could do
> 2000 VLAN add/delete with 64 port-VLAN members / sec on my test VM.
> If it ever becomes a problem we can optimize it further, for the time
> being I prefer it is simpler.

Very nice!

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

A couple of nits that you can handle later (or not):

1. Patch #3:

__vlan_delete_pvid(vg, rtnl_dereference(vg->pvid));

Can be simplified to:

RCU_INIT_POINTER(vg->pvid, NULL);

2. Patch #7:

Initially I thought that 'fwd.vlan' is never set, but then I realized
that in the only place where this field is actually set it's called
'dst.vlan', which is a bit confusing given that in the context of the
bridge driver 'dst' is usually an FDB entry. I would probably rename it
to 'fwd' to be consistent with the rest of the code.