| Message ID | 1610660990-18812-1-git-send-email-jjohnson@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
On Thu, Jan 14, 2021 at 1:50 PM Jeff Johnson <jjohnson@codeaurora.org> wrote: > > From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > > Modules with a large number of compilation units may be > exceeding AR and LD command argument list. Handle this gracefully by > writing the long argument list in a file. The command line options > read from file are inserted in place of the original @file option. > > The usage is well documented at > https://www.gnu.org/software/make/manual/html_node/File-Function.html > > Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org> > --- > > Changes in v2: > - Remove spurious endif > > scripts/Makefile.build | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 252b7d2..787dca2 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -425,7 +425,10 @@ $(obj)/lib.a: $(lib-y) FORCE > # module is turned into a multi object module, $^ will contain header file > # dependencies recorded in the .*.cmd file. > quiet_cmd_link_multi-m = LD [M] $@ > - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) > + cmd_link_multi-m = \ > + $(file >$@.in,$(filter %.o,$^)) \ > + $(LD) $(ld_flags) -r -o $@ @$@.in; \ > + rm -f $@.in The GNU Make docs linked above use an `@` before the invocation of `rm`. I don't know what that's about, but that or even this patch doesn't affect my ability to build negatively. LGTM Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> > > $(multi-used-m): FORCE > $(call if_changed,link_multi-m) > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
On Fri, Jan 15, 2021 at 6:50 AM Jeff Johnson <jjohnson@codeaurora.org> wrote: > > From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > > Modules with a large number of compilation units may be > exceeding AR and LD command argument list. Handle this gracefully by > writing the long argument list in a file. The command line options > read from file are inserted in place of the original @file option. > > The usage is well documented at > https://www.gnu.org/software/make/manual/html_node/File-Function.html > > Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org> > --- First, is this a real problem? If so, which module is exceeding the command line limit? $(file ) is only supported by GNU Make 4.0 or later. The current minimum version is GNU Make 3.81. If we need this feature, Documentation/process/changes.rst must be updated. But, more importantly, none of your patches works correctly. Since $(file ...) is evaluated into an empty string, your patches would break the Kbuild ability that detects the command changes. Steps to reproduce the problem ------------------------------ [1] add a module foo that consists of three objects foo1.o, foo2.o, foo3.o For example, like follows: obj-m += foo.o foo-objs := foo1.o foo2.o foo3.o [2] Run 'make modules' You will get the module foo. [3] Drop foo3.o from the module members Change Makefile as follows: obj-m += foo.o foo-objs := foo1.o foo2.o [4] Re-run 'make modules' The current build system cleverly notices the Makefile change, and correctly rebuilds the foo module. With your patch set applied, the build system would not rebuild the module. > Changes in v2: > - Remove spurious endif > > scripts/Makefile.build | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 252b7d2..787dca2 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -425,7 +425,10 @@ $(obj)/lib.a: $(lib-y) FORCE > # module is turned into a multi object module, $^ will contain header file > # dependencies recorded in the .*.cmd file. > quiet_cmd_link_multi-m = LD [M] $@ > - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) > + cmd_link_multi-m = \ > + $(file >$@.in,$(filter %.o,$^)) \ > + $(LD) $(ld_flags) -r -o $@ @$@.in; \ > + rm -f $@.in > > $(multi-used-m): FORCE > $(call if_changed,link_multi-m) > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
On Fri, Jan 15, 2021 at 10:01 AM Nick Desaulniers <ndesaulniers@google.com> wrote: > > On Thu, Jan 14, 2021 at 1:50 PM Jeff Johnson <jjohnson@codeaurora.org> wrote: > > > > From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > > > > Modules with a large number of compilation units may be > > exceeding AR and LD command argument list. Handle this gracefully by > > writing the long argument list in a file. The command line options > > read from file are inserted in place of the original @file option. > > > > The usage is well documented at > > https://www.gnu.org/software/make/manual/html_node/File-Function.html > > > > Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > > Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org> > > --- > > > > Changes in v2: > > - Remove spurious endif > > > > scripts/Makefile.build | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > > index 252b7d2..787dca2 100644 > > --- a/scripts/Makefile.build > > +++ b/scripts/Makefile.build > > @@ -425,7 +425,10 @@ $(obj)/lib.a: $(lib-y) FORCE > > # module is turned into a multi object module, $^ will contain header file > > # dependencies recorded in the .*.cmd file. > > quiet_cmd_link_multi-m = LD [M] $@ > > - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) > > + cmd_link_multi-m = \ > > + $(file >$@.in,$(filter %.o,$^)) \ > > + $(LD) $(ld_flags) -r -o $@ @$@.in; \ > > + rm -f $@.in > > The GNU Make docs linked above use an `@` before the invocation of > `rm`. I don't know what that's about, but that or even this patch > doesn't affect my ability to build negatively. LGTM See this: https://www.gnu.org/software/make/manual/html_node/Echoing.html#Echoing > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Tested-by: Nick Desaulniers <ndesaulniers@google.com> > > > > > $(multi-used-m): FORCE > > $(call if_changed,link_multi-m) > > -- > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > > a Linux Foundation Collaborative Project > > > > > -- > Thanks, > ~Nick Desaulniers
On 2021-01-14 17:12, Masahiro Yamada wrote: > On Fri, Jan 15, 2021 at 6:50 AM Jeff Johnson <jjohnson@codeaurora.org> > wrote: >> >> From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> >> >> Modules with a large number of compilation units may be >> exceeding AR and LD command argument list. Handle this gracefully by >> writing the long argument list in a file. The command line options >> read from file are inserted in place of the original @file option. >> >> The usage is well documented at >> https://www.gnu.org/software/make/manual/html_node/File-Function.html >> >> Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> >> Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org> >> --- > > > > > First, is this a real problem? > If so, which module is exceeding the command line limit? On 2021-01-14 17:12, Masahiro Yamada wrote: > First, is this a real problem? > If so, which module is exceeding the command line limit? Mahesh & I appreciate all of the feedback. The issue is seen in an Android environment with an out-of-tree driver. The combination of long path names and a large number of source files is leading to the issue. Since Mahesh & I are not Kbuild gurus, is there an alternative solution to this issue? Jeff -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
On Sat, Jan 16, 2021 at 5:15 AM <jjohnson@codeaurora.org> wrote: > > On 2021-01-14 17:12, Masahiro Yamada wrote: > > On Fri, Jan 15, 2021 at 6:50 AM Jeff Johnson <jjohnson@codeaurora.org> > > wrote: > >> > >> From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > >> > >> Modules with a large number of compilation units may be > >> exceeding AR and LD command argument list. Handle this gracefully by > >> writing the long argument list in a file. The command line options > >> read from file are inserted in place of the original @file option. > >> > >> The usage is well documented at > >> https://www.gnu.org/software/make/manual/html_node/File-Function.html > >> > >> Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> > >> Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org> > >> --- > > > > > > > > > > First, is this a real problem? > > If so, which module is exceeding the command line limit? > > On 2021-01-14 17:12, Masahiro Yamada wrote: > > First, is this a real problem? > > If so, which module is exceeding the command line limit? > > Mahesh & I appreciate all of the feedback. > > The issue is seen in an Android environment with an out-of-tree > driver. The combination of long path names and a large number > of source files is leading to the issue. > > Since Mahesh & I are not Kbuild gurus, is there an alternative > solution to this issue? > > Jeff I see. The support for out-of-tree modules is not nice in this regard, but fixing it would need many changes. The long-term solution might be to upstream your driver, but it might not be possible. One cheesy workaround might be to point the module path via a symbolic link. Let's say your module is located in a very deep directory, /home/foo/long/long/.../path/to/your/module make M=/home/foo/long/long/.../path/to/your/module modules would fail due to the too long command line. First, create a symbolic link as follows: ln -s /home/foo/long/long/.../path/to/your/module mod_dir Then, pass the symbolic link to M= option. make M=mod_dir modules
On 2021-01-15 13:53, Masahiro Yamada wrote: > On Sat, Jan 16, 2021 at 5:15 AM <jjohnson@codeaurora.org> wrote: >> >> On 2021-01-14 17:12, Masahiro Yamada wrote: >> > On Fri, Jan 15, 2021 at 6:50 AM Jeff Johnson <jjohnson@codeaurora.org> >> > wrote: >> >> >> >> From: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> >> >> >> >> Modules with a large number of compilation units may be >> >> exceeding AR and LD command argument list. Handle this gracefully by >> >> writing the long argument list in a file. The command line options >> >> read from file are inserted in place of the original @file option. >> >> >> >> The usage is well documented at >> >> https://www.gnu.org/software/make/manual/html_node/File-Function.html >> >> >> >> Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org> >> >> Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org> >> >> --- >> > >> > >> > >> > >> > First, is this a real problem? >> > If so, which module is exceeding the command line limit? >> >> On 2021-01-14 17:12, Masahiro Yamada wrote: >> > First, is this a real problem? >> > If so, which module is exceeding the command line limit? >> >> Mahesh & I appreciate all of the feedback. >> >> The issue is seen in an Android environment with an out-of-tree >> driver. The combination of long path names and a large number >> of source files is leading to the issue. >> >> Since Mahesh & I are not Kbuild gurus, is there an alternative >> solution to this issue? >> >> Jeff > > > I see. > > The support for out-of-tree modules > is not nice in this regard, but fixing it > would need many changes. > Agree with that. I checked the same after your first comment on this thread. It needs changes in multiple layers of makefiles. > > The long-term solution might be to upstream your driver, > but it might not be possible. > > > > > > > One cheesy workaround might be to point the module path > via a symbolic link. > > > Let's say your module is located in a very deep > directory, > /home/foo/long/long/.../path/to/your/module > > > make M=/home/foo/long/long/.../path/to/your/module modules > > would fail due to the too long command line. > > > > > First, create a symbolic link as follows: > > ln -s /home/foo/long/long/.../path/to/your/module mod_dir > > > Then, pass the symbolic link to M= option. > > make M=mod_dir modules Thanks for the suggestion. Earlier, we have used a similar workaround of using relative path instead of absolute to reduce the command line length. What's your input on the following approach where we link object files in different stages to reduce the command line length. ./Makefile # foo.c is combined and final module. obj-m = fooa.o foob.o fooc.o # link already combined object files fooc-y := fooa.o foob.o # combine into different groups fooa-y := foo1.o foo2.o foob-y := foo3.o foo4.o .... Note: We need to add MODULE_LICENSE in every group. make -C ../linux-kbuild M=/local/mnt2/workspace/dev/foo modules CC [M] /local/mnt2/workspace/dev/foo/foo1.o CC [M] /local/mnt2/workspace/dev/foo/foo2.o LD [M] /local/mnt2/workspace/dev/foo/fooa.o CC [M] /local/mnt2/workspace/dev/foo/foo3.o CC [M] /local/mnt2/workspace/dev/foo/foo4.o LD [M] /local/mnt2/workspace/dev/foo/foob.o LD [M] /local/mnt2/workspace/dev/foo/fooc.o MODPOST /local/mnt2/workspace/dev/foo/Module.symvers CC [M] /local/mnt2/workspace/dev/foo/fooa.mod.o LD [M] /local/mnt2/workspace/dev/foo/fooa.ko CC [M] /local/mnt2/workspace/dev/foo/foob.mod.o LD [M] /local/mnt2/workspace/dev/foo/foob.ko CC [M] /local/mnt2/workspace/dev/foo/fooc.mod.o LD [M] /local/mnt2/workspace/dev/foo/fooc.ko
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 252b7d2..787dca2 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -425,7 +425,10 @@ $(obj)/lib.a: $(lib-y) FORCE # module is turned into a multi object module, $^ will contain header file # dependencies recorded in the .*.cmd file. quiet_cmd_link_multi-m = LD [M] $@ - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) + cmd_link_multi-m = \ + $(file >$@.in,$(filter %.o,$^)) \ + $(LD) $(ld_flags) -r -o $@ @$@.in; \ + rm -f $@.in $(multi-used-m): FORCE $(call if_changed,link_multi-m)