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8a78756eb5
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>
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| arm | ||
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| c6x | ||
| cris | ||
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| h8300 | ||
| hexagon | ||
| ia64 | ||
| m32r | ||
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| metag | ||
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| mn10300 | ||
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| powerpc | ||
| s390 | ||
| score | ||
| sh | ||
| sparc | ||
| tile | ||
| um | ||
| unicore32 | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| Kconfig | ||