[VLAN] Slow device creation + procfs overflows

[Mike Ireton]

Howdy,

    I've noted two problems which I am not sure weather or not are 8021q 
specfic, but google doesn't seem to have any similar mailing list 
posting documenting these issues.

    I have a simple script which creates 2000 vlan devices and, damm, it 
runs slow! Device creation can be as slow as 2 devices per second and 
there are very noticable pauses during  execution. I have noted also 
that if I access certain /proc files during this time, device creation 
halts completely. The speed of device creation does not appear related 
to the number done or index - indeed, the first 20 devices are just as 
slow as the last 20. I suppose it's not too awfully important and 
doesn't really have much overall impact because device creation is such 
an infrequent event even on a very busy network server such as dedicated 
pppoe box. I just thought I'd bring it up for comment.

    Secondly, under linux 2.4.27 (but not under 2.6.8 that I can see), 
there appears to be a maximum number of devices that can be registered 
before I start getting kernel errors for "VLAN: failed to add proc entry 
for xxxx". My test script creates the devices in a loop and sets an ip 
address as each comes up, and seems to get 108 devices created before 
the errors start appearing. If I omit the 'ifconfig', then there doesn't 
seem to be any problem and I can create all 2000 devices. Under kernel 
2.6.8, I can run the same test script with ifconfig the new interfaces 
and no problem appears. I have also noted that under 2.4.32, the issue 
also appears to affect listing of ppp interfaces in 
/proc/sys/net/ipv4/conf/ where if I have 450 or so actual pppd's 
running, this directory only lists about 119 interfaces total. This 
sounds like a procfs limitation (in 2.4) but I'm not that familliar with 
the different peices to know for sure.

Comments?

Mike-


    I realise the speed of device creation is probbly not too important 
and probbly involves device structure locking issues that we don't want 
to visit. Th