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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2017-11-13 11:29:37 +0100 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2017-11-16 01:07:35 +0100 |
| commit | 8a78756eb545a6fb8007fa154a626ca2bc208027 (patch) | |
| tree | a5f6f791cf742128df2d9af0cfba1393cae0b0c4 /scripts/Makefile.host | |
| parent | kbuild: filter-out PHONY targets from "targets" (diff) | |
| download | linux-8a78756eb545a6fb8007fa154a626ca2bc208027.tar.xz linux-8a78756eb545a6fb8007fa154a626ca2bc208027.zip | |
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 'scripts/Makefile.host')
| -rw-r--r-- | scripts/Makefile.host | 12 |
1 files changed, 0 insertions, 12 deletions
diff --git a/scripts/Makefile.host b/scripts/Makefile.host index 9cfd5c84d76f..a5e03838eca8 100644 --- a/scripts/Makefile.host +++ b/scripts/Makefile.host @@ -48,15 +48,6 @@ host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs))) host-cshobjs := $(sort $(foreach m,$(host-cshlib),$($(m:.so=-objs)))) host-cxxshobjs := $(sort $(foreach m,$(host-cxxshlib),$($(m:.so=-objs)))) -# output directory for programs/.o files -# hostprogs-y := tools/build may have been specified. -# Retrieve also directory of .o files from prog-objs or prog-cxxobjs notation -host-objdirs := $(dir $(__hostprogs) $(host-cobjs) $(host-cxxobjs)) - -host-objdirs := $(strip $(sort $(filter-out ./,$(host-objdirs)))) - - -__hostprogs := $(addprefix $(obj)/,$(__hostprogs)) host-csingle := $(addprefix $(obj)/,$(host-csingle)) host-cmulti := $(addprefix $(obj)/,$(host-cmulti)) host-cobjs := $(addprefix $(obj)/,$(host-cobjs)) @@ -66,9 +57,6 @@ host-cshlib := $(addprefix $(obj)/,$(host-cshlib)) host-cxxshlib := $(addprefix $(obj)/,$(host-cxxshlib)) host-cshobjs := $(addprefix $(obj)/,$(host-cshobjs)) host-cxxshobjs := $(addprefix $(obj)/,$(host-cxxshobjs)) -host-objdirs := $(addprefix $(obj)/,$(host-objdirs)) - -obj-dirs += $(host-objdirs) ##### # Handle options to gcc. Support building with separate output directory |