empty kbuild rebuilding all 2.6.13-mm3 ia64 sn2

empty kbuild rebuilding all 2.6.13-mm3 ia64 sn2

[Paul Jackson]

Using 2.6.13-mm3, building for SN2 (an ia64 arch) using sn2_defconfig,
after doing a full successful build, if I just issue another 'make',
it builds more or less every file all over again.  When I am just
working in one *.c file, this causes make to be much more expensive
than it should, rebuilding everything, instead of just that one file
and relinking (or close to that).

No doubt you will need some additional information, unless I get
lucky and you recognize the problem already.

But I don't know what you will be needing, so I'll just have to
wait for the request.

And there is a good chance that it's something bogus on my end.
I say this simply because I don't notice anyone else complaining
about this on lkml, so quite possibly it's just me seeing this.

An empty make begins with:

  CHK     include/linux/version.h
  CC      arch/ia64/kernel/asm-offsets.s
  GEN     include/asm-ia64/asm-offsets.h
  CHK     usr/initramfs_list
  CC      init/main.o
  CC      arch/ia64/mm/init.o
  AS      arch/ia64/ia32/ia32_entry.o
  CC      arch/ia64/sn/kernelsetup.o

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

Re: empty kbuild rebuilding all 2.6.13-mm3 ia64 sn2

[Sam Ravnborg]

On Fri, Sep 16, 2005 at 01:54:12AM -0700, Paul Jackson wrote:
> Using 2.6.13-mm3, building for SN2 (an ia64 arch) using sn2_defconfig,
> after doing a full successful build, if I just issue another 'make',
> it builds more or less every file all over again.  When I am just
> working in one *.c file, this causes make to be much more expensive
> than it should, rebuilding everything, instead of just that one file
> and relinking (or close to that).

You are hit by the circular dependency in asm-offsets.h.
Tony Luck posted a fix for this to the ia64 list yesterday.

The problem in short is that asm-offsets.c includes asm-offsets.h which it
is also used to generate. So unless they get same timestamp the
kernel will recompile.

	Sam