From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arun Sharma Subject: Re: [PATCH] net: compute a more reasonable default ip6_rt_max_size Date: Fri, 25 May 2012 17:08:59 -0700 Message-ID: <4FC01F1B.1080009@fb.com> References: <1337976934-18065-1-git-send-email-asharma@fb.com> <1337978820.10135.1.camel@edumazet-glaptop> <4FC0063E.8080209@fb.com> <20120525.185131.2017517041016424794.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: , , To: David Miller Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:47911 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752474Ab2EZAJO (ORCPT ); Fri, 25 May 2012 20:09:14 -0400 In-Reply-To: <20120525.185131.2017517041016424794.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 5/25/12 3:51 PM, David Miller wrote: > From: Arun Sharma > Date: Fri, 25 May 2012 15:22:54 -0700 > >> On 5/25/12 1:47 PM, Eric Dumazet wrote: >>> On Fri, 2012-05-25 at 13:15 -0700, Arun Sharma wrote: >>>> The algorithm is based on ipv4 and alloc_large_system_hash(). >>>> >>> >>> Why is it needed at all ? >>> >>> IPv4 has a route cache with potentially millions of entries, not IPv6. >> >> With the default size of 4096 for the ipv6 routing table, entries can >> get garbage collected and hosts could lose their default route and >> therefore lose connectivity. >> >> We actually saw it happen. > > Under no circumstances should administrator configured ipv6 routes be > garbage collected, that is a bug. These were not admin configured routes. They were discovered via ipv6 neighbor discovery. -Arun