Re: tip: bzip2/lzma now in tip:x86/setup-lzma

Alain Knaff
2009-02-18T09:41:17Z

Jan Engelhardt wrote:
> On Wednesday 2009-02-18 08:48, Alain Knaff wrote:
>>> The sanest thing to do is to
>>> compress with all the compressors that are configured into the kernel,
>>> and then use the smallest image of the ones that can be produced,
>>> *including the uncompressed image*.
>> ... so, if I understood correctly, that would mean compressing the
>> kernel 4 times, and keeping the smallest?
>> Given the relatively low speed of compression, I feel that such a
>> feature would really annoy people who compile their kernel often (such
>> as kernel or module developers).
>
> I would expect of *module* developers to build their code by means of
> an out-of-tree directory, thereby not causing regeneration of the
> vmlinux binary or initramfs image. Even if they stayed within the
> Linux srctree, they could take a shortcut by explicitly stating the
> target (`make that/foo.ko`). modpost is still something that takes
> much more time with allmodconfig than compressing the kernel and/or
> changed modules over and over.

You are right of course for modules inserted by insmod modprobe. But what
about people who tune parts that must be compiled-in (VFS layer, etc.), or
that investigate a bug in a module that only occurs when it is compiled
into the kernel?

>> Btw, what *is* the standard work flow of supplying your own built-in
>> initramfs? Do such developers usually supply a directory tree, or do
>> they already cpio it before supplying it to the kernel? Or do they even
>> compress it themselves?
>
> As for me: a separate staging directory that is totally unrelated to
> the Linux tree, and manually running the cpio command. And not
> embodying it into the kernel because all bootloaders used so far
> support reading an extra initramfs image.

Interesting. If that is the case in general, for all developers of embedded
systems, then we might be able to do away with compression of the built-in
initramfs altogether, as proposed in the very early versions of my patch.

Regards,

Alain