linux-kernel - Re: [PATCH v5 3/3] kbuild: generate autoksyms.h early

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Message-ID: <CAK7LNASCrTj4_RgtxvZm0ei_HExYaPPMJodngKXBOL+=GODv5w@mail.gmail.com>
Date:   Fri, 28 Feb 2020 19:42:41 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Quentin Perret <qperret@...gle.com>
Cc:     Nicolas Pitre <nico@...xnic.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Matthias Maennich <maennich@...gle.com>,
        "Cc: Android Kernel" <kernel-team@...roid.com>,
        Jessica Yu <jeyu@...nel.org>,
        Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH v5 3/3] kbuild: generate autoksyms.h early

On Tue, Feb 18, 2020 at 6:41 PM Quentin Perret <qperret@...gle.com> wrote:
>
> When doing a cold build, autoksyms.h starts empty, and is updated late
> in the build process to have visibility over the symbols used by in-tree
> drivers. But since the symbol whitelist is known upfront, it can be used
> to pre-populate autoksyms.h and maximize the amount of code that can be
> compiled to its final state in a single pass, hence reducing build time.
>
> Do this by using gen_autoksyms.sh to initialize autoksyms.h instead of
> creating an empty file.
>
> Acked-by: Nicolas Pitre <nico@...xnic.net>
> Tested-by: Matthias Maennich <maennich@...gle.com>
> Reviewed-by: Matthias Maennich <maennich@...gle.com>
> Signed-off-by: Quentin Perret <qperret@...gle.com>
> ---
>  Makefile                 | 7 +++++--
>  scripts/gen_autoksyms.sh | 3 ++-
>  2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 84b71845c43f..17b7e7f441bd 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1062,9 +1062,12 @@ endif
>
>  autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)
>
> +quiet_cmd_autoksyms_h = GEN     $@
> +      cmd_autoksyms_h = mkdir -p $(dir $@); $(CONFIG_SHELL) \
> +                       $(srctree)/scripts/gen_autoksyms.sh $@


When you send v6,
could you wrap the line as follows (CONFIG_SHELL in the next line)  ?

         cmd_autoksyms_h = mkdir -p $(dir $@); \
                          $(CONFIG_SHELL) $(srctree)/scripts/gen_autoksyms.sh $@


This still fits in 80-cols.

Thanks.




> +
>  $(autoksyms_h):
> -       $(Q)mkdir -p $(dir $@)
> -       $(Q)touch $@
> +       $(call cmd,autoksyms_h)
>
>  ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
>
> diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh
> index 6c625f52118f..679c9f05e4b4 100755
> --- a/scripts/gen_autoksyms.sh
> +++ b/scripts/gen_autoksyms.sh
> @@ -39,7 +39,8 @@ cat > "$output_file" << EOT
>
>  EOT
>
> -sed 's/ko$/mod/' modules.order |
> +[ -f modules.order ] && modlist=modules.order || modlist=/dev/null
> +sed 's/ko$/mod/' $modlist |
>  xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
>  cat - "$ksym_wl" |
>  sort -u |
> --
> 2.25.0.265.gbab2e86ba0-goog
>


-- 
Best Regards
Masahiro Yamada