Re: [patch] measurements, numbers about CONFIG_OPTIMIZE_INLINING=y impact

[Sam Ravnborg <sam@ravnborg.org>]

On Fri, Jan 09, 2009 at 11:44:10PM +0100, Andi Kleen wrote:
> > Fetch a gigabyte's worth of data for the debuginfo RPM? 
> 
> The suse 11.0 kernel debuginfo is ~120M.

How is this debuginfo generated?

Someone have posted the following patch which I did not apply in lack
of any real need. But maybe distroes have something similar already
so it makes sense to apply it.

	Sam

Subject: [PATCH] Kbuild: generate debug info in building

This patch will generate kernel debuginfo in Kbuild when invoking "make
debug_info". The separate debug files are in .debug under building tree.
They can help the cases of requiring debug info for tracing/debug tools,
especially cross-compilation. Moreover, it can simplify or standardize
the packaging process for the distributions those will provide
kernel-debuginfo.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
---
 Makefile                 |   14 ++++++++++++++
 scripts/Makefile.modpost |   14 ++++++++++++++
 2 files changed, 28 insertions(+), 0 deletions(-)


diff --git a/Makefile b/Makefile
index 7f9ff9b..eed7510 100644
--- a/Makefile
+++ b/Makefile
@@ -814,6 +814,20 @@ define rule_vmlinux-modpost
        $(Q)echo 'cmd_$@ := $(cmd_vmlinux-modpost)' > $(dot-target).cmd
 endef

+ifdef CONFIG_DEBUG_INFO
+quiet_cmd_vmlinux_debug = GEN     $<.debug
+      cmd_vmlinux_debug = mkdir -p .debug;                          \
+                          $(OBJCOPY) --only-keep-debug              \
+                                     $< .debug/$<.debug
+targets += vmlinux.debug
+endif
+
+debug_info: vmlinux FORCE
+ifdef CONFIG_DEBUG_INFO
+       $(call if_changed,vmlinux_debug)
+       $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $@
+endif
+
 # vmlinux image - including updated kernel symbols
 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o
$(kallsyms.o) FORCE
 ifdef CONFIG_HEADERS_CHECK
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index f4053dc..0df73b2 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -137,6 +137,20 @@ $(modules): %.ko :%.o %.mod.o FORCE

 targets += $(modules)

+modules-debug := $(modules:.ko=.ko.debug)
+ifdef CONFIG_DEBUG_INFO
+quiet_cmd_debug_ko = GEN     $@
+      cmd_debug_ko = mkdir -p .debug/`dirname $@`;                     \
+                    $(OBJCOPY) --only-keep-debug $< .debug/$@
+targets += $(modules-debug)
+endif
+
+debug_info: $(modules-debug) FORCE
+
+$(modules-debug): $(modules) FORCE
+ifdef CONFIG_DEBUG_INFO
+       $(call if_changed,debug_ko)
+endif

 # Add FORCE to the prequisites of a target to force it to be always
rebuilt.
 #
---------------------------------------------------------------------------