Subject: Re: [PATCH 00/10 net-next] Convert CONFIG_IPV6 to built-in and remove stubs

From: Jakub Kicinski <[email-masked]>
Date: Mon, 9 Mar 2026 16:18:26 -0700

On Mon, 9 Mar 2026 11:26:08 +0100 Krzysztof Kozlowski wrote:
> Heh, I just checked, that's 6 MB module on arm64 which apparently you
> want to put into the kernel!

Pretty sure you get 6MB because you have DEBUG_INFO enabled?
IMO "I have full debug info but I care about kernel size" is
internally inconsistent.

Here is the top line of bloatometer without debug info:

  add/remove: 1769/7 grow/shrink: 86/0 up/down: 374521/-228 (374293)

The vmlinux increases by 200kB with IPv6 built in.
Not a very dramatic increase.

Please note that opening any dual-stack socket will cause the IPv6
module to get loaded. And opening a dual-stack socket will fail if 
IPv6 is blacklisted. So I find it quite hard to believe that other
that deeply embedded systems with custom configs there are systems
out there which don't end up with IPv6 loaded. Whether they have 
a single IPv6 address configured or not.

And if we stop supporting =m we can actually turn a bunch of indirect
calls into static inlines so in practice the memory use on real system
will be lower! 

Please be reasonable, this is objectively the right move.