On Tue, Nov 15, 2022 at 02:46:17AM +0900, Masahiro Yamada wrote:
> Prior to commit 5d45950dfbb1 ("kbuild: move vmlinux.o link to
> scripts/Makefile.vmlinux_o"), jobserver-exec was invoked from the shell
> script, link-vmlinux.sh. It can get access to the jobserver because
> Makefile adds '+' prefix, as in:
>
> +$(call if_changed_dep,link_vmlinux)
>
> Since 5d45950dfbb1, jobserver-exec is invoked from Makefile, but the
> '+' prefix is missing, hence jobserver-exec has no access to the
> jobserver.
>
> Fixes: 5d45950dfbb1 ("kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o")
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
At least it doesn't seem like compile times were majorly affected. I
benchmarked arm64 allmodconfig (worst case scenario with ThinLTO):
Benchmark 1: 094226ad94f4 ("Linux 6.1-rc5")
Time (mean ± σ): 899.036 s ± 1.133 s [User: 49314.495 s, System: 3840.796 s]
Range (min … max): 898.118 s … 900.302 s 3 runs
Benchmark 2: 0f45cbb5399b ("kbuild: revive parallel execution for .tmp_initcalls.lds rule")
Time (mean ± σ): 898.482 s ± 0.152 s [User: 49329.703 s, System: 3836.408 s]
Range (min … max): 898.306 s … 898.584 s 3 runs
Summary
'0f45cbb5399b ("kbuild: revive parallel execution for .tmp_initcalls.lds rule")' ran
1.00 ± 0.00 times faster than '094226ad94f4 ("Linux 6.1-rc5")'
> ---
>
> scripts/Makefile.vmlinux_o | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
> index 0edfdb40364b..ae52d3b3f063 100644
> --- a/scripts/Makefile.vmlinux_o
> +++ b/scripts/Makefile.vmlinux_o
> @@ -19,7 +19,7 @@ quiet_cmd_gen_initcalls_lds = GEN $@
>
> .tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
> vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
> - $(call if_changed,gen_initcalls_lds)
> + +$(call if_changed,gen_initcalls_lds)
>
> targets := .tmp_initcalls.lds
>
> --
> 2.34.1
>
