[Crash-utility] ARM support for CONFIG_SPARSEMEM: (was Re: DDimage)

[Dave Anderson]

----- Original Message -----
> ----- Original Message -----
> > Hi Dave,
> >
> > Now I am quite sure the definition of NR_SECTION_ROOTS() is wrong.
> > In the upstream kernel, I found the following
> > include/linux/mmzone.h
> > ...
> > 994 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
> > 995 #define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
> > 996 #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
> >
> > and include/kernel.h DIV_ROUND_UP is defined as follows,
> > 58 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
> >
> > I hope you can take care of this.
> >
> > By the way, I think _SECTION_SIZE_BITS issue is a separate issue.
> >
> > Best Regard,
> >
> > Takuo
> 
> Hello Takuo,

... [ cut ] ... 

> I'll test this out, and presuming that nothing breaks w/respect to
> backwards compatibility, I'll change the crash version of
> NR_SECTION_ROOTS.
> 
> But, as you state, the _SECTION_SIZE_BITS is based upon whatever your
> kernel is doing.
> 
> Thanks,
> Dave

Hello Takuo,

I have tested and queued this patch for the next release:

diff -u -r1.466 defs.h
--- defs.h      11 May 2011 13:24:36 -0000      1.466
+++ defs.h      25 May 2011 18:31:39 -0000
@@ -2184,7 +2184,8 @@
 #define _SECTIONS_PER_ROOT()   (1)
 
 #define SECTION_NR_TO_ROOT(sec)        ((sec) / SECTIONS_PER_ROOT())
-#define NR_SECTION_ROOTS()     (NR_MEM_SECTIONS() / SECTIONS_PER_ROOT())
+#define DIV_ROUND_UP(n,d)      (((n) + (d) - 1) / (d))
+#define NR_SECTION_ROOTS()     (DIV_ROUND_UP(NR_MEM_SECTIONS(), SECTIONS_PER_ROOT()))
 #define SECTION_ROOT_MASK()    (SECTIONS_PER_ROOT() - 1)
 
 /*

Thanks for catching this,
  Dave