| Message ID | 20220505072244.1155033-16-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kbuild: yet another series of cleanups (modpost, LTO, MODULE_REL_CRCS) | expand |
On Thu, May 05, 2022 at 04:22:44PM +0900 Masahiro Yamada wrote: > Like built-in.a, the command length of the *.mod rule scales with > the depth of the directory times the number of objects in the Makefile. > > Add $(obj)/ by the shell command (awk) instead of by Make's builtin > function. > > In-tree modules still have some room to the limit (ARG_MAX=2097152), > but this is more future-proof for big modules in a deep directory. > > For example, you can build i915 as a module (CONFIG_DRM_I915=m) and > compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. > > The issue is more critical for external modules because the M= path > can be very long as Jeff Johnson reported before [1]. > > [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/ > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- > > (no changes since v2) > > Changes in v2: > - New patch > > scripts/Makefile.build | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index cea48762299c..e7b3f329d443 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -266,8 +266,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE > $(call if_changed_rule,cc_o_c) > $(call cmd,force_checksrc) > > -cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ > - $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ > +cmd_mod = echo $(call real-search, $*.o, .o, -objs -y -m) | \ > + $(AWK) -v RS='( |\n)' '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ > > $(obj)/%.mod: FORCE > $(call if_changed,mod) > -- > 2.32.0 Thanks! At work, some colleagues of mine stumbled over that problem, too. Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index cea48762299c..e7b3f329d443 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -266,8 +266,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) -cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ - $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ +cmd_mod = echo $(call real-search, $*.o, .o, -objs -y -m) | \ + $(AWK) -v RS='( |\n)' '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ $(obj)/%.mod: FORCE $(call if_changed,mod)
Like built-in.a, the command length of the *.mod rule scales with the depth of the directory times the number of objects in the Makefile. Add $(obj)/ by the shell command (awk) instead of by Make's builtin function. In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as a module (CONFIG_DRM_I915=m) and compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. The issue is more critical for external modules because the M= path can be very long as Jeff Johnson reported before [1]. [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- (no changes since v2) Changes in v2: - New patch scripts/Makefile.build | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)