Date: Fri, 25 May 2012 18:51:31 -0400 (EDT)
Message-Id: <20120525.185131.2017517041016424794.davem@davemloft.net>
To: asharma@fb.com
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: compute a more reasonable default ip6_rt_max_size
From: David Miller <davem@davemloft.net>
In-Reply-To: <4FC0063E.8080209@fb.com>
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From: Arun Sharma <asharma@fb.com>
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.
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