From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0DF5A3E8693; Tue, 10 Mar 2026 20:02:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773172965; cv=none; b=nSZFPXzXk5xOd6O6rFw+/bp02LkD3T7SJh94eeJOunZQvAJl+dBOQiNfhzZ/OxATyVdx74OOCEQWZbiBZdIaeFg/6lCoMpyRanhyfF5ErIf/9isB3+OWGXbuLVxNeMwmaNpVTAu6dnoeP4NMei11YVxrWYiTycfGmau/8R3Q5co= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773172965; c=relaxed/simple; bh=vHd0VEFZ+Pg8KfcMbMmBXHtIfaZNvkk4N1vOcpruSJw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=td6rbiVNC04vDg76LaaTx+drjKO/RppaLnqMiyYDpJP9ZMvwvrBmBwCZ17yFgNDeg4C0hch3aMAIdNhhvUm4D0FXLppyHT42e7hsEQv2jJ7UQNhshZ75Bt7Nj/aiaAP2771LxonhRDry/cHHpj/FIjK5BVIe+pux1KBFkoRYjNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AesxHHdH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AesxHHdH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D70FFC19423; Tue, 10 Mar 2026 20:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773172964; bh=vHd0VEFZ+Pg8KfcMbMmBXHtIfaZNvkk4N1vOcpruSJw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=AesxHHdH7pt9am+/onq+fA1Ro9jP5fy3kMVzraQ9SItXhOT/ryvmJnnjNnVzIoD2Z 0cHOvJGluH9vQwCgua2URdqC2QHpSIpAhz/ZWgPU8n7UaapUEfH5eDopvJ7pCp76NJ +rBLkLJaAw9fFlM/m9pKTetRUZX2tM2jZHe3oD/Ub3JaoSDIkdmrHI/B72WFwtY6x+ smlJ9gGhJq5x8SsMzOyILzJj16Woe4VQ+TE7qrztrYLJi7Gne7A4ZU9iQmcsGIGcKh einNfqRjS7Zs/74yHGMpRTco7qsx1foQMwM3Hk5kHjh9gUfPXPKDOm1ikkZJIPreuG tBcCEvr5cjNfg== Message-ID: <411bcf03-5993-478d-9809-3e04567ff09a@kernel.org> Date: Tue, 10 Mar 2026 21:02:40 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/10 net-next] Convert CONFIG_IPV6 to built-in and remove stubs To: Jakub Kicinski Cc: Fernando Fernandez Mancera , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, dsahern@kernel.org References: <20260309022013.5199-1-fmancera@suse.de> <48ccec3f-dbc8-45c8-afda-e4f7e8f150d6@kernel.org> <20260309161826.46074d55@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/03/2026 00:18, Jakub Kicinski wrote: > 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? Yeah, that was defconfig with KASAN, not full debug info. defconfig comes with deduced debug info. In one of other email threads I corrected that actual size on distro kernel is much smaller, e.g. 200-400 kB depending on arch or distro settings. > IMO "I have full debug info but I care about kernel size" is > internally inconsistent. My argument is that many of arm64 devices I work with have fixed partition sizes, come with their own bootloader which uses separate fixed-size boot partition. I still want to be able to load arm64 defconfig into that boot partition. If it does not fit, I need to tweak defconfig, e.g. disable some options. I find it valid usecase and I was disagreeing here with that cloud-only or big-machines-only approach. > > 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. Yes, Ubuntu for that reasons does not have it even as module. This should be used as *the* argument for these changes. > > 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. I am very reasonable, just need to hear reasons. Just to remind - none of the machines I have, none of the routers, none of the mobile phones on 4G and 5G receive IPv6 so they don't actually need it. Not having IPv6 built-in is therefore a valid use case. Best regards, Krzysztof