Subject: Re: [PATCH] net: compute a more reasonable default ip6_rt_max_size

From: Arun Sharma <[email-masked]>
Date: Fri, 25 May 2012 17:08:59 -0700

On 5/25/12 3:51 PM, David Miller wrote:
> From: Arun Sharma<[email-masked]>
> 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