Date:   Mon, 6 Mar 2023 11:19:54 +0700
From:   Bagas Sanjaya <bagasdotme@gmail.com>
To:     Thorsten Leemhuis <linux@leemhuis.info>,
        Jonathan Corbet <corbet@lwn.net>
Cc:     Randy Dunlap <rdunlap@infradead.org>,
        Lukas Bulwahn <lukas.bulwahn@gmail.com>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        regressions@lists.linux.dev
Subject: Re: [PATCH v3] docs: describe how to quickly build a trimmed kernel
Message-ID: <ZAVp6jdeWzYcisUO@debian.me>
References: <1a788a8e7ba8a2063df08668f565efa832016032.1678021408.git.linux@leemhuis.info>
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On Sun, Mar 05, 2023 at 02:04:44PM +0100, Thorsten Leemhuis wrote:
> + * Create the build configuration for your kernel based on an existing
> +   configuration.
> +
> +   If you already prepared such a '.config' file yourself, copy it to
> +   ~/linux/ and run ``make olddefconfig``.
> +
> +   Use the same command, if your distribution or somebody else already t=
ailored
> +   your running kernel to your or your hardware's needs: the make target
> +   'olddefconfig' will then try to use that kernel's .config as base.
> +
> +   Using this make target is fine for everybody else, too -- but you oft=
en can
> +   save a lot of time by using this command instead::
> +
> +     yes "" | make localmodconfig
> +
> +   This will try to pick your distribution's kernel as base, but then di=
sable
> +   modules for any features apparently superfluous for your setup. This =
will
> +   reduce the compile time enormously, especially if you are running an
> +   universal kernel from a commodity Linux distribution.
> +
> +   There is a catch: the make target 'localmodconfig' will disable kernel
> +   features you have not directly or indirectly through some program uti=
lized
> +   since you booted the system. You can reduce or nearly eliminate that =
risk by
> +   using tricks outlined in the reference section; for quick testing pur=
poses
> +   that risk is often negligible, but it is an aspect you want to keep i=
n mind
> +   in case your kernel behaves oddly.

If your distro config have ``CONFIG_IKCONFIG=3Dy``, you can copy from
procfs::

    zcat /proc/config.gz > .config

If it isn't the case, you may want to enable the aforementioned config
option.

Thanks.=20

--=20
An old man doll... just what I always wanted! - Clara

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