Re: [PATCH][ia64] Fix the difference between node_mem_map and node_start_pfn. (Re: makedumpfile fails on SGI machine)

[Jay Lan <jlan@sgi.com>]

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Ken'ichi Ohmichi wrote:
> Hi Bernhard, Jay,
> 
> Bernhard Walle wrote:
>> Hi Ken'ichi Ohmichi,
>>
>> * Jay Lan [2008-08-27 18:43]:
>>> Thanks for your patch!
>>>
>>> I am wondering if the discontigmem kernel has a legitimate bug,
>>> we probably should report it?
>>>
>>> I tested your patch on a machine that used to fail in executing
>>> 'makedumpfile'. It now generated a dump file fine.
>> thanks for the patch, I can also report that with the patch and with
>> vmlinux it works now.
> 
> Thank you for the report. It's a good news :-)
> 
> 
>> However, shouldn't we add that vmem_map to VMCOREINFO of the kernel?

Hmm, it failed on a shub2 machine. (The previous on that worked was a
shub1 machine, an A3700. An A4700 is a shub2.) I assumed the warning
about kernel version 2.6.27 not supported was harmless?

a4700rac:~ # /bin/makedumpfile-1.2.7-0.2 -c -d31 -x
/boot/vmlinux-2.6.27-rc4-vanilla /proc/vmcore /diskdump/dumpfile
Can't distinguish the pgtable.
The kernel version is not supported.
The created dumpfile may be incomplete.
Excluding unnecessary pages        : [  0 %] readmem: Can't convert a
virtual address(a07ffff9df8f5800) to offset.
create_2nd_bitmap: Can't exclude unnecessary pages.

makedumpfile Failed.
a4700rac:~ #

I will try your kernel patch next.

Regards,
 - jay

> 
> I think that we would rather fix the kernel bug than add vmem_map to
> VMCOREINFO of the kernel. If fixing it, makedumpfile does not need
> vmem_map.
> 
> The attached patch fixes the kernel bug, and makedumpfile can work without
> '-x' option. I tested it on my ia64 none-NUMA machine, and it works fine.
> Could you test the attached patch on your machine again ?
> 
> 
> Thanks
> Ken'ichi Ohmichi
> 
> ---
> [PATCH][ia64] Fix the difference between node_mem_map and node_start_pfn.
> 
> makedumpfile[1] cannot run on ia64 discontigmem kernel, because the member
> node_mem_map of struct pgdat_list has invalid value. This patch fixes it.
> 
> node_start_pfn shows the start pfn of each node, and node_mem_map should
> point 'struct page' of each node's node_start_pfn.
> On my machine, node0's node_start_pfn shows 0x400 and its node_mem_map points
> 0xa0007fffbf000000. This address is the same as vmem_map, so the node_mem_map
> points 'struct page' of pfn 0, even if its node_start_pfn shows 0x400.
> 
> The cause is due to the round down of min_pfn in count_node_pages().
> This patch fixes it.
> 
> 
> makedumpfile[1]: dump filtering command
> https://sourceforge.net/projects/makedumpfile/
> 
> Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
> ---
> --- a/arch/ia64/mm/discontig.c	2008-08-29 23:05:52.000000000 +0900
> +++ b/arch/ia64/mm/discontig.c	2008-08-29 23:06:59.000000000 +0900
> @@ -631,7 +631,6 @@ static __init int count_node_pages(unsig
>  			(min(end, __pa(MAX_DMA_ADDRESS)) - start) >>PAGE_SHIFT;
>  #endif
>  	start = GRANULEROUNDDOWN(start);
> -	start = ORDERROUNDDOWN(start);
>  	end = GRANULEROUNDUP(end);
>  	mem_data[node].max_pfn = max(mem_data[node].max_pfn,
>  				     end >> PAGE_SHIFT);
> --- a/include/asm-ia64/meminit.h	2008-08-29 23:06:36.000000000 +0900
> +++ b/include/asm-ia64/meminit.h	2008-08-29 23:06:48.000000000 +0900
> @@ -47,7 +47,6 @@ extern int reserve_elfcorehdr(unsigned l
>   */
>  #define GRANULEROUNDDOWN(n)	((n) & ~(IA64_GRANULE_SIZE-1))
>  #define GRANULEROUNDUP(n)	(((n)+IA64_GRANULE_SIZE-1) & ~(IA64_GRANULE_SIZE-1))
> -#define ORDERROUNDDOWN(n)	((n) & ~((PAGE_SIZE<<MAX_ORDER)-1))
>  
>  #ifdef CONFIG_NUMA
>    extern void call_pernode_memory (unsigned long start, unsigned long len, void *func);
> _
> 
> 
> 
> ------------------------------------------------------------------------
> 
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