Re: [PATCH] SPARSEMEM + NUMA can't handle unaligned memory regions?

[Michael Ellerman]

On Tue, 2006-05-09 at 09:32 +0100, Andy Whitcroft wrote:
> Michael Ellerman wrote:
> > I can't believe I'm the first person to see this, so I imagine I'm missing
> > something. Perhaps it's only an issue on powerpc?
> > 
> > I have a machine with some memory at 0, then a hole, and then some more memory
> > which doesn't start on a section boundary. This is causing the following
> > crash:
> > 
> > add_region nid 1 start_pfn 0x77c0 pages 0x840
> > add_region nid 1 start_pfn 0x0 pages 0x6000
> 
> Nasty, could you send me your full boot log and your config and I'll
> have a look at it.  I can say this code has been booted on a lot of
> power boxes and I've never seen that before!  :)

Ah yeah, I seem to have neglected to mention it's a kdump boot :} Sorry.
That's why we get the strangely aligned memory sections. The section
starting at 0 is for the kdump kernel, the bit at 0x77c0 covers some
firmware that's allocated there by the first kernel.

I can still give you a .config and log if you want it, but not 'til
tomorrow morning.

> Anyhow, will take a look and see if we can avoid iterating over the area
> to find it.

Yeah it's a bit nasty having the loop. I figure on most configs it'll
pop on the first iteration, but still.

cheers

-- 
Michael Ellerman
IBM OzLabs

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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