Re: [PATCH] recipes-initramfs/compress-initrd: add recipe to compress initrd with xz

["MOESSBAUER, Felix" <felix.moessbauer@siemens.com>]

On Mon, 2024-05-13 at 10:56 +0530, srinuvasan.a via isar-users wrote:
> From: srinuvasan <srinuvasan.a@siemens.com>
> 
> By default initrd compressed with zstd tool, with the present

Hi, the standard for bullseye is gz.

> bullseye base image
> of amd64 the initrd size is almost 27MB, this can be reduced with the
> help of xz tool,
> using this one the generated initrd size is almost 18MB, we saved
> almost 9MB.
> 
> Signed-off-by: srinuvasan <srinuvasan.a@siemens.com>
> ---
>  meta-isar/conf/local.conf.sample               |  2 +-
>  .../compress-initrd/compress-initrd.bb         | 18
> ++++++++++++++++++
>  .../compress-initrd/files/postinst             |  5 +++++
>  3 files changed, 24 insertions(+), 1 deletion(-)
>  create mode 100644 meta-isar/recipes-initramfs/compress-
> initrd/compress-initrd.bb
>  create mode 100644 meta-isar/recipes-initramfs/compress-
> initrd/files/postinst
> 
> diff --git a/meta-isar/conf/local.conf.sample b/meta-
> isar/conf/local.conf.sample
> index 17455015..ac8b749e 100644
> --- a/meta-isar/conf/local.conf.sample
> +++ b/meta-isar/conf/local.conf.sample
> @@ -149,7 +149,7 @@ CONF_VERSION = "1"
>  
>  #
>  # The default list of extra packages to be installed.
> -IMAGE_INSTALL = "hello-isar example-raw example-module-
> ${KERNEL_NAME} enable-fsck isar-exclude-docs samefile hello isar-
> disable-apt-cache cowsay example-prebuilt"
> +IMAGE_INSTALL = "hello-isar example-raw example-module-
> ${KERNEL_NAME} enable-fsck isar-exclude-docs samefile hello isar-
> disable-apt-cache cowsay example-prebuilt compress-initrd"
>  
>  #
>  # Machines with secure boot should use signed modules.
> diff --git a/meta-isar/recipes-initramfs/compress-initrd/compress-
> initrd.bb b/meta-isar/recipes-initramfs/compress-initrd/compress-
> initrd.bb
> new file mode 100644
> index 00000000..21e28782
> --- /dev/null
> +++ b/meta-isar/recipes-initramfs/compress-initrd/compress-initrd.bb
> @@ -0,0 +1,18 @@
> +# Compress the initrd with better compression tool
> +#
> +# This software is a part of ISAR.
> +
> +DESCRIPTION = "Compress the initrd with better compression tool"

This description makes is too vague.

> +MAINTAINER = "Your name here <you@domain.com>"

No ;)

> +
> +inherit dpkg-raw
> +
> +DEBIAN_DEPENDS = "linux-image-${KERNEL_NAME}, xz-utils, initramfs-
> tools"
> +
> +SRC_URI = " \
> +    file://postinst \
> +"
> +do_install() {
> +    install -v -d "${D}/etc/initramfs-tools/conf.d/"
> +    echo "COMPRESS=xz" >

Please don't hardcode values. Further, we need to have the compression
utility installed to be able to perform that compression. For xz,
that's xz-utils.

In general, I like the idea to make this customizable (even if I like
zstd more than xz because xz requires a lot of resources for
decompression). However, I'm wondering if we can implement this using
the imagetypes infrastructure (@Adriaan, in CC). That would make it
consistent across ISAR and also avoid the introduction of additional
variables.

Felix

> "${D}/etc/initramfs-tools/conf.d/${PN}.conf"
> +}
> diff --git a/meta-isar/recipes-initramfs/compress-
> initrd/files/postinst b/meta-isar/recipes-initramfs/compress-
> initrd/files/postinst
> new file mode 100644
> index 00000000..0db52142
> --- /dev/null
> +++ b/meta-isar/recipes-initramfs/compress-initrd/files/postinst
> @@ -0,0 +1,5 @@
> +#!/bin/sh
> +
> +set -e
> +
> +update-initramfs -c -k all
> -- 
> 2.39.2
> 

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