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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Tue, 15 Nov 2022 03:02:24 +0900
Message-ID: <CAK7LNAS7i9wY1PS-841_7ufvS-ctF8GGH3OSQ=gu7FaOAMT0Vg@mail.gmail.com>
Subject: Re: [PATCH 03/46] kbuild: lto: preserve MAKEFLAGS for module linking
To:     "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc:     linux-kernel@vger.kernel.org, Martin Liska <mliska@suse.cz>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Jiri Slaby <jslaby@suse.cz>
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On Mon, Nov 14, 2022 at 8:44 PM Jiri Slaby (SUSE) <jirislaby@kernel.org> wr=
ote:
>
> From: Martin Liska <mliska@suse.cz>
>
> Prefix cc_o_c and ld_multi_m commands in makefile in order to preserve
> access to jobserver. This is needed for gcc LTO at least (enabled in
> later patches in this series). Note that both commands can invoke the
> linker (ld_single_m in the former case).
>
> Fixes this warning:
> lto-wrapper: warning: jobserver is not available: =E2=80=98--jobserver-au=
th=3D=E2=80=99 is not present in =E2=80=98MAKEFLAGS=E2=80=99
>
> Cc: Sedat Dilek <sedat.dilek@gmail.com>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Michal Marek <michal.lkml@markovi.net>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Fixes: 5d45950dfbb1 (kbuild: move vmlinux.o link to scripts/Makefile.vmli=
nux_o)


Same as 02.

Also, 5d45950dfbb1 did not touch scripts/Makefile.build at all.
Please stop adding random, wrong Fixes.


Make already compiles many files in parallel.
It does not make sense to request a jobserver for
a single C file compilation.

Is there any way to turn off this annoyance?


> Signed-off-by: Martin Liska <mliska@suse.cz>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> ---
>  scripts/Makefile.build | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 41f3602fc8de..564a20ce2667 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -247,7 +247,7 @@ endef
>
>  # Built-in and composite module parts
>  $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
> -       $(call if_changed_rule,cc_o_c)
> +       +$(call if_changed_rule,cc_o_c)
>         $(call cmd,force_checksrc)
>
>  # To make this rule robust against "Argument list too long" error,
> @@ -457,7 +457,7 @@ endef
>  $(multi-obj-m): objtool-enabled :=3D $(delay-objtool)
>  $(multi-obj-m): part-of-module :=3D y
>  $(multi-obj-m): %.o: %.mod FORCE
> -       $(call if_changed_rule,ld_multi_m)
> +       +$(call if_changed_rule,ld_multi_m)
>  $(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
>
>  # Add intermediate targets:
> --
> 2.38.1
>


--=20
Best Regards
Masahiro Yamada