APPLIED[M/U]: [MANTIC][PATCH 0/3] Enable zstd compressed modules

[Andrea Righi]

On Wed, Jul 26, 2023 at 08:24:50PM +0100, Dimitri John Ledkov wrote:
> This patch series achieves multiple related features in concert,
> whilst trying to minimise the fallout.
> 
> Specifically, as discussed on ubuntu-devel [1] to accelerate initrd
> creation, minimize its size, and move as much compression from runtime
> machines to build. At the same time, I want to prevent any unncessary
> breakage w.r.t. building launchpad & non-launchpad signed kernel
> modules, as all of those operate on uncomprssed modules only.
> 
> This patch series enables in-kernel zstd module decompression support
> that can be used by new enough kmod (as available in mantic-proposed).
> 
> The kernel modules are zstd compressed in parallel with maximum
> compression (higher than kernel default makefiles) at the time when
> .debs are assembled. Also note that modules packages are now kept
> uncompressed - to avoid nested compression. This does make .deb files
> larger than before, but much faster to build and install - as the
> installed contents is significantly smaller now:
> 
>   # du --si -s 6.4.0-0-generic 6.4.0-0-generic-uncompressed
>   152M	6.4.0-0-generic
>   567M	6.4.0-0-generic-uncompressed
> 
> Note that makefile is patched to not attempt installing random modules
> compressed, this is to ensure that any dkms / lrm / modules
> builds. This is hopefully to mitigate any compatibility issues with
> dkms / lrm / module signing that may be deployed elsewhere.
> 
> Given the significant size reduction, we may also attempt to drop
> modules/modules-extra packages split, and instead diffirentiate things
> only on whether or not linux-firmware is installed. However, that too
> is undergoing size optimisations.
> 
> [1] https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/042652.html

Applied to mantic/linux and mantic/linux-unstable.

Thanks,
-Andrea