Re: [PATCH v5 0/2] kbuild: distributed build support for Clang ThinLTO

[Nathan Chancellor <nathan@kernel.org>]

Hi Nicolas,

On Tue, Oct 28, 2025 at 06:28:20PM +0000, xur@google.com wrote:
> From: Rong Xu <xur@google.com>
> 
> ChangeLog:
> 
> V5: Handle single quote escaping in echo _c_flags to fix
>     Piotr Gorski's reported error.
> 
> V4: This is based on the reimplementation provided by Masahiro Yamada
> on May 26. The difference is that this version now saves the compiler
> flags (_c_flags) from the Front-End (FE) compilation and re-uses them
> for the subsequent Back-End (BE) compilation.
>  
> Rong Xu (2):
>   kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
>   kbuild: distributed build support for Clang ThinLTO
> 
>  .gitignore                 |  2 +
>  Makefile                   | 25 +++++-------
>  arch/Kconfig               | 19 +++++++++
>  scripts/Makefile.lib       |  7 ++++
>  scripts/Makefile.thinlto   | 40 ++++++++++++++++++
>  scripts/Makefile.vmlinux_a | 83 ++++++++++++++++++++++++++++++++++++++
>  scripts/mod/modpost.c      | 15 +++++--
>  7 files changed, 174 insertions(+), 17 deletions(-)
>  create mode 100644 scripts/Makefile.thinlto
>  create mode 100644 scripts/Makefile.vmlinux_a

I have been running this for a few months locally and I have not noticed
any problems with it (at least for the two distribution configurations I
regularly test). I think this looks good overall and seems fairly well
contained thanks to Masahiro's work on the earlier revisions. Could this
be picked up in kbuild-next-unstable so it can bake in -next for a
little bit? It should still be applicable.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>

Cheers,
Nathan