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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2017-11-13 19:29:37 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2017-11-16 09:07:35 +0900 |
| commit | 8a78756eb545a6fb8007fa154a626ca2bc208027 (patch) | |
| tree | a5f6f791cf742128df2d9af0cfba1393cae0b0c4 /arch/x86/entry/vdso | |
| parent | 591f66899784ae0afa13ff9a3eb5ce0a4358e48b (diff) | |
kbuild: create object directories simpler and faster
For the out-of-tree build, scripts/Makefile.build creates output
directories, but this operation is not efficient.
scripts/Makefile.lib calculates obj-dirs as follows:
obj-dirs := $(dir $(multi-objs) $(obj-y))
Please notice $(sort ...) is not used here. Usually the result is
as many "./" as objects here.
For a lot of duplicated paths, the following command is invoked.
_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
Then, the costly shell command is run over and over again.
I see many points for optimization:
[1] Use $(sort ...) to cut down duplicated paths before passing them
to system call
[2] Use single $(shell ...) instead of repeating it with $(foreach ...)
This will reduce forking.
[3] We can calculate obj-dirs more simply. Most of objects are already
accumulated in $(targets). So, $(dir $(targets)) is fine and more
comprehensive.
I also removed ugly code in arch/x86/entry/vdso/Makefile. This is now
really unnecessary.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Diffstat (limited to 'arch/x86/entry/vdso')
| -rw-r--r-- | arch/x86/entry/vdso/Makefile | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index d5409660f5de..f8e3d85256ad 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -129,10 +129,6 @@ $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1 -# This makes sure the $(obj) subdirectory exists even though vdso32/ -# is not a kbuild sub-make subdirectory. -override obj-dirs = $(dir $(obj)) $(obj)/vdso32/ - targets += vdso32/vdso32.lds targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o targets += vdso32/vclock_gettime.o |