Re: [GIT PULL 1/2] Kbuild updates for v5.6-rc1

[Masahiro Yamada]

Hi Linus,

On Sun, Feb 2, 2020 at 3:45 AM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Jan 31, 2020 at 8:06 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> >
> >  - simplify built-in initramfs creation
>
> Hmm.
>
> This may simplify it from a _technical_ angle, but it seems to be a
> fairly annoying step backwards from a UI perspective.
>
> Now Kconfig asks a completely pointless question that most people have
> absolutely zero interest in. The old situation was better, I feel.
>
> Basically, I feel that from a "get normal users to test development
> kernels", our Kconfig pain ends up being the biggest hurdle by far.
>
> The kernel is easy to build and doesn't really require all that much
> infrastructure, but generating the config - particularly when it
> changes over time and you can't just say "just use the distro config"
> - is a big step for people.
>
> So honestly, while I've pulled this, I feel that this kind of change
> is going _exactly_ the wrong way when it asks people questions that
> they don't care one whit about.
>
> If I as a kernel developer can't find it in myself to care and go "why
> does it ask this new question", then that should tell you something.
>
> Why do we have this choice in the first place?



Generally, initramfs is passed from a boot-loader,
but some architectures embed initramfs into vmlinux
(perhaps due to poor boot-loader support??)

arch/arc/configs/tb10x_defconfig:CONFIG_INITRAMFS_SOURCE="../tb10x-rootfs.cpio"
arch/unicore32/configs/defconfig:#CONFIG_INITRAMFS_SOURCE="arch/unicore/ramfs/ramfs_config"
arch/xtensa/configs/cadence_csp_defconfig:CONFIG_INITRAMFS_SOURCE="$$KERNEL_INITRAMFS_SOURCE"

So, data-compression is useful - that's is what I understand.


For major architectures, vmlinux embeds a tiny initramfs,
which is generated based on usr/default_cpio_list.

We do not need data-compression for such a small cpio,
but handling it in a consistent way is sensible.
This is annoying from the users' PoV, I admit.



> And no, it's not a
> "simplification" to make life more complex for users.
>
>                    Linus



-- 
Best Regards
Masahiro Yamada