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Date: Thu, 18 May 2023 20:35:02 -0600
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Subject: Re: [RFC PATCH net-next v2 0/2] Mitigate the Issue of Expired Routes
 in Linux IPv6 Routing Tables
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To: Kui-Feng Lee <sinquersw@gmail.com>, Kui-Feng Lee <thinker.li@gmail.com>,
 netdev@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
 kernel-team@meta.com, davem@davemloft.net, edumazet@google.com,
 kuba@kernel.org, pabeni@redhat.com
Cc: Kui-Feng Lee <kuifeng@meta.com>, Ido Schimmel <idosch@idosch.org>
References: <20230517183337.190591-1-kuifeng@meta.com>
 <61248e45-c619-d5f2-95a0-5971593fbe8d@kernel.org>
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 <1284f846-f8ed-d95a-4476-40e2de26c092@gmail.com>
From: David Ahern <dsahern@kernel.org>
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On 5/18/23 12:51 PM, Kui-Feng Lee wrote:
> This is one of solutions I considered at beginning.
> With this approach, we can have a maximum
> number of entries like what neighbor tables do.
> Remove entries only if the list reach the maximum without running
> a GC timer.  However, it can be very inefficient to insert a new entry
> ordered. Stephen mentioned 3 million routes on backbone router
> in another message.  We may need something more complicated
> like RB-tree or HEAP to reduce the overhead.

I do not believe so. Not every route will have an expiration timer. Only
those are added to the new, time ordered list_head.

And you can not cap the number of entries in a FIB.