Re: [uml-devel] [PATCH 9/10] UML - Big memory fixes

[Blaisorblade <blaisorblade@yahoo.it>]

On Monday 31 October 2005 05:39, Jeff Dike wrote:
> A number of fixes to improve behavior when large physical memory sizes
> are specified:
>     libc files need -D_FILE_OFFSET_BITS=64 because there are unavoidable
> uses of non-64 interfaces in libc
>     some %d need to be %u
>
> Signed-off-by: Jeff Dike <jdike@addtoit.com>

Jeff, please always make patch and ChangeLog match. Yes, it matters - when it 
doesn't happen there's always something bad going on.

> Index: linux-2.6.14/arch/um/kernel/mem.c
> ===================================================================
> --- linux-2.6.14.orig/arch/um/kernel/mem.c	2005-10-28 12:58:12.000000000
> -0400 +++ linux-2.6.14/arch/um/kernel/mem.c	2005-10-30 19:29:04.000000000
> -0500 @@ -235,7 +235,7 @@ void paging_init(void)
>  	for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++)
>  		zones_size[i] = 0;
>  	zones_size[0] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
> -	zones_size[2] = highmem >> PAGE_SHIFT;
> +	zones_size[3] = highmem >> PAGE_SHIFT;
>  	free_area_init(zones_size);

What's this? It's IMHO invalid. free_area_init() intereprets these values with 
include/linux/mmzone.h: ZONE_* constants.

Why those are not used here it's a nice question.

I think this came up because there's (in -mm) Andi Kleen created a new zone 
(ZONE_DMA32) for devices using 32-bit only DMA - but it seems it's not in 
mainline).  (I don't know if that patch is in -mm actually, but I guess it 
from this patch content).

Actually, since MAX_NR_ZONES is 3, and we are assigning to zones_size[3],
we're corrupting data:

        unsigned long zones_size[MAX_NR_ZONES], vaddr;

Don't drop the patch however, I'm fixing all this up.
-- 
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade

		
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