Re: [PATCH v2] initramfs: restore default compression behavior

[Masahiro Yamada]

On Mon, Mar 16, 2020 at 8:25 PM Eugeniy Paltsev
<Eugeniy.Paltsev@xxxxxxxxxxxx> wrote:
>
> Even though INITRAMFS_SOURCE kconfig option isn't set in most of
> defconfigs it is used (set) extensively by various build systems.
> Commit f26661e12765 ("initramfs: make initramfs compression choice
> non-optional") has changed default compression mode. Previously we
> compress initramfs using available compression algorithm. Now
> we don't use any compression at all by default.
> It significantly increases the image size in case of build system
> chooses embedded initramfs. Initially I faced with this issue while
> using buildroot.
>
> As of today it's not possible to set preferred compression mode
> in target defconfig as this option depends on INITRAMFS_SOURCE
> being set. Modification of all build systems either doesn't look
> like good option.
>
> Let's instead rewrite initramfs compression mode choices list
> the way that "INITRAMFS_COMPRESSION_NONE" will be the last option
> in the list. In that case it will be chosen only if all other
> options (which implements any compression) are not available.
>
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>


Applied to linux-kbuild.
Thanks.



> ---
>  usr/Kconfig | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/usr/Kconfig b/usr/Kconfig
> index bdf5bbd40727..96afb03b65f9 100644
> --- a/usr/Kconfig
> +++ b/usr/Kconfig
> @@ -124,17 +124,6 @@ choice
>
>           If in doubt, select 'None'
>
> -config INITRAMFS_COMPRESSION_NONE
> -       bool "None"
> -       help
> -         Do not compress the built-in initramfs at all. This may sound wasteful
> -         in space, but, you should be aware that the built-in initramfs will be
> -         compressed at a later stage anyways along with the rest of the kernel,
> -         on those architectures that support this. However, not compressing the
> -         initramfs may lead to slightly higher memory consumption during a
> -         short time at boot, while both the cpio image and the unpacked
> -         filesystem image will be present in memory simultaneously
> -
>  config INITRAMFS_COMPRESSION_GZIP
>         bool "Gzip"
>         depends on RD_GZIP
> @@ -207,4 +196,15 @@ config INITRAMFS_COMPRESSION_LZ4
>           If you choose this, keep in mind that most distros don't provide lz4
>           by default which could cause a build failure.
>
> +config INITRAMFS_COMPRESSION_NONE
> +       bool "None"
> +       help
> +         Do not compress the built-in initramfs at all. This may sound wasteful
> +         in space, but, you should be aware that the built-in initramfs will be
> +         compressed at a later stage anyways along with the rest of the kernel,
> +         on those architectures that support this. However, not compressing the
> +         initramfs may lead to slightly higher memory consumption during a
> +         short time at boot, while both the cpio image and the unpacked
> +         filesystem image will be present in memory simultaneously
> +
>  endchoice
> --
> 2.21.1
>


-- 
Best Regards
Masahiro Yamada