Re: [PATCH] hashed device lookup (Does NOT meet Linus' sumission

[Matti Aarnio]

On Sun, Jan 07, 2001 at 01:42:50PM +0000, Alan Cox wrote:
> > + *      NOTE:  That is no longer true with the addition of VLAN tags.  Not
> > + *             sure which should go first, but I bet it won't make much
> > + *             difference if we are running VLANs.  The good news is that
> 
> It makes a lot of difference tha the vlan goes 2nd. Most sane people wont
> have vlans active on a high load interface.

	VLAN tag header appears as Layer-3 protocol, which then
	causes loop into VLAN reception code and back to generic
	Layer-3 receiver.

	I just tried to pull data from another machine, which
	is on normal port thru VLAN trunking port to receiving
	machine, and got fast-ether at wire speed. (As near as
	ncftp's 11.11 MB/sec is wirespeed..)

> So fix the algorithm. You want the list sorted at this point, or to generate
> a bitmap of free/used entries and scan the list then scan the map
> 
> Question: How do devices with hardware vlan support fit into your model ?

	Hardware VLAN support at several network cards is just
	to recognize VLAN tags, and then do the right thing
	( = skip 4 bytes ) when doing TCP/UDP checksum.

> Alan

/Matti Aarnio