[PATCH] ARM: mm: Regarding section when dealing with meminfo

Russell King - ARM Linux linux at arm.linux.org.uk
Sun Jan 23 13:05:32 EST 2011


On Thu, Jan 20, 2011 at 10:11:27AM -0800, Dave Hansen wrote:
> On Thu, 2011-01-20 at 18:01 +0000, Russell King - ARM Linux wrote:
> > > The x86 version of show_mem() actually manages to do this without any
> > > #ifdefs, and works for a ton of configuration options.  It uses
> > > pfn_valid() to tell whether it can touch a given pfn.
> > 
> > x86 memory layout tends to be very simple as it expects memory to
> > start at the beginning of every region described by a pgdat and extend
> > in one contiguous block.  I wish ARM was that simple.
> 
> x86 memory layouts can be pretty funky and have been that way for a long
> time.  That's why we *have* to handle holes in x86's show_mem().  My
> laptop even has a ~1GB hole in its ZONE_DMA32:

If x86 is soo funky, I suggest you try the x86 version of show_mem()
on an ARM platform with memory holes.  Make sure you try it with
sparsemem as well...



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