From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755198Ab0KHRqA (ORCPT ); Mon, 8 Nov 2010 12:46:00 -0500 Received: from mail.candelatech.com ([208.74.158.172]:43248 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752927Ab0KHRp6 (ORCPT ); Mon, 8 Nov 2010 12:45:58 -0500 Message-ID: <4CD83752.1070501@candelatech.com> Date: Mon, 08 Nov 2010 09:45:54 -0800 From: Ben Greear Organization: Candela Technologies User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc11 Thunderbird/3.0.4 MIME-Version: 1.0 To: Eric Dumazet CC: NetDev , linux-kernel , Tejun Heo Subject: Re: OOM when adding ipv6 route: How to make available more per-cpu memory? References: <4CD43C87.5040403@candelatech.com> <1288980361.2882.1070.camel@edumazet-laptop> <4CD449A5.5070305@candelatech.com> <1288988403.2665.268.camel@edumazet-laptop> <1288995103.2665.653.camel@edumazet-laptop> <4CD49C2F.3060904@candelatech.com> <1289028392.2665.2418.camel@edumazet-laptop> <4CD58B9C.2030006@candelatech.com> <1289214131.2820.187.camel@edumazet-laptop> In-Reply-To: <1289214131.2820.187.camel@edumazet-laptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/08/2010 03:02 AM, Eric Dumazet wrote: > Le samedi 06 novembre 2010 à 10:08 -0700, Ben Greear a écrit : > >> At least I don't see any percpu dumps in dmesg. I vaguely remember >> someone posting some ipv6 address scalability patches some time back. >> I think they had to hack on /proc fs as well. I'll see if I can >> dig those up. >> >>> Make sure udev / hotplug is not the problem, if you create your devices >>> very fast. >> >> We can create the macvlans w/out problem, though I'm sure that could >> be sped up. The problem is when we try to add IPv6 addresses to >> them. > > I see. Did you check /proc/sys/net/ipv6/ tunables ? > > For example, I bet you need to make route/max_size a bigger value than > default (4096) > > Following is working for me > > echo 16384>/proc/sys/net/ipv6/route/max_size > modprobe dummy numdummies=2000 > for a in `seq 1 1999` > do > ip -6 add add 4444::444:$a/24 dev dummy$a > done > > ip -6 ro | wc -l > 6008 That helps. I'm getting all of the IP addrs set now, but having trouble with some of the default gateways (I have one routing table per interface). ./local/sbin/ip -6 route replace default via 2002:9:8::1 dev eth7#458 table 726 RTNETLINK answers: No buffer space available dmesg is full of this: [247106.294743] ipv6: Neighbour table overflow. A quick look in /proc didn't show a tunable for this, but I'll go grub through the code. As for the route/max_size, it would be nice to see some useful kernel message in dmesg when this hit. Just telling the user '-ENOMEM' is not at all sufficient to help them figure out the problem. For that matter, why is there such a limit anyway? IPv4 doesn't appear to have any such limit? Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com