Re: 05e0caad3b7bd0d0fbeff980bca22f186241a501 breaks ia64 kdump

[Christian Cotte-Barrot <Christian.Cotte-Barrot@bull.net>]

Why the above Bob's patch not included in 2.6.19 ?

It is still needed to boot ia64 platform.

Mel Gorman wrote:
>>>As you say, it's not clear why the normal discontig kernel boots because
>>>the regions should have been skipped by add_active_range().
>>>
>>
>>  I think that depends on the init value of memmap, if they are all zero,
>>  free_pages_check will be happy and not report any thing. So I guess we may
>>  see this bug in normal kernel with a warm reboot, or with a machine which
>>  PROM does not clear memory to all zero.
> 
> It could have been just luck. See more below
> 
>>
>>>Try your patch and see does it work for kdump. It should work fine in the
>>>normal case because at very worst, slightly more memmap is allocated than
>>>is strictly required.
>>>
>>
>>  It works for kdump.
>>
> 
> Can you try out the patch below please as a possibly simplier alternative? It's
> a patch from Bob Picco that addresses a similar problem with initmem on a
> kernel booting as normal. The only difference between Bob's original patch
> and this one is the addition of the CONFIG_KEXEC stuff from your patch. It
> survived a simply boot test.
> 
> Thanks
> 
>>>>Begin Bob's patch
> 
> While pursuing and unrelated issue with 64Mb granules I noticed a problem
> related to inconsistent use of add_active_range. There doesn't appear any
> reason to me why FLATMEM versus DISCONTIG_MEM should register memory
> to add_active_range with different code. So I've changed the code into
> a common implementation. 
> 
> The other subtle issue fixed by this patch was calling add_active_range
> in count_node_pages before granule aligning is performed. We were lucky with
> 16MB granules but not so with 64MB granules. count_node_pages has reserved
> regions filtered out and as a consequence linked kernel text and data
> aren't covered by calls to count_node_pages. So linked kernel regions
> wasn't reported to add_active_regions. This resulted in free_initmem causing
> numerous bad_page reports. This won't occur with this patch because now
> all known memory regions are reported by register_active_ranges.
> 
> Acked-by: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Bob Picco <bob.picco@hp.com>
> 
>  arch/ia64/mm/contig.c      |    3 +--
>  arch/ia64/mm/discontig.c   |    4 +++-
>  arch/ia64/mm/init.c        |   24 +++++++++++++++++-------
>  include/asm-ia64/meminit.h |    3 ++-
>  4 files changed, 23 insertions(+), 11 deletions(-)
> 
> diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/arch/ia64/mm/contig.c linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/contig.c
> --- linux-2.6.19-rc5-clean/arch/ia64/mm/contig.c	2006-11-08 02:24:20.000000000 +0000
> +++ linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/contig.c	2006-11-16 15:29:31.000000000 +0000
> @@ -226,7 +226,6 @@ void __init
>  paging_init (void)
>  {
>  	unsigned long max_dma;
> -	unsigned long nid = 0;
>  	unsigned long max_zone_pfns[MAX_NR_ZONES];
>  
>  	num_physpages = 0;
> @@ -238,7 +237,7 @@ paging_init (void)
>  	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
>  
>  #ifdef CONFIG_VIRTUAL_MEM_MAP
> -	efi_memmap_walk(register_active_ranges, &nid);
> +	efi_memmap_walk(register_active_ranges, NULL);
>  	efi_memmap_walk(find_largest_hole, (u64 *)&max_gap);
>  	if (max_gap < LARGE_GAP) {
>  		vmem_map = (struct page *) 0;
> diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/arch/ia64/mm/discontig.c linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/discontig.c
> --- linux-2.6.19-rc5-clean/arch/ia64/mm/discontig.c	2006-11-08 02:24:20.000000000 +0000
> +++ linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/discontig.c	2006-11-16 15:29:31.000000000 +0000
> @@ -473,6 +473,9 @@ void __init find_memory(void)
>  			node_clear(node, memory_less_mask);
>  			mem_data[node].min_pfn = ~0UL;
>  		}
> +
> +	efi_memmap_walk(register_active_ranges, NULL);
> +
>  	/*
>  	 * Initialize the boot memory maps in reverse order since that's
>  	 * what the bootmem allocator expects
> @@ -654,7 +657,6 @@ static __init int count_node_pages(unsig
>  {
>  	unsigned long end = start + len;
>  
> -	add_active_range(node, start >> PAGE_SHIFT, end >> PAGE_SHIFT);
>  	mem_data[node].num_physpages += len >> PAGE_SHIFT;
>  	if (start <= __pa(MAX_DMA_ADDRESS))
>  		mem_data[node].num_dma_physpages +> diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/arch/ia64/mm/init.c linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/init.c
> --- linux-2.6.19-rc5-clean/arch/ia64/mm/init.c	2006-11-08 02:24:20.000000000 +0000
> +++ linux-2.6.19-rc5-register_all_memory/arch/ia64/mm/init.c	2006-11-16 15:33:25.000000000 +0000
> @@ -594,18 +594,28 @@ find_largest_hole (u64 start, u64 end, v
>  	return 0;
>  }
>  
> +#endif /* CONFIG_VIRTUAL_MEM_MAP */
> +
>  int __init
> -register_active_ranges(u64 start, u64 end, void *nid)
> +register_active_ranges(u64 start, u64 end, void *arg)
>  {
> -	BUG_ON(nid = NULL);
> -	BUG_ON(*(unsigned long *)nid >= MAX_NUMNODES);
> +	int nid = paddr_to_nid(__pa(start));
> +
> +	if (nid < 0)
> +		nid = 0;
>  
> -	add_active_range(*(unsigned long *)nid,
> -				__pa(start) >> PAGE_SHIFT,
> -				__pa(end) >> PAGE_SHIFT);
> +#ifdef CONFIG_KEXEC
> +	if (start > crashk_res.start && start < crashk_res.end)
> +		start = max(start, crashk_res.end);
> +	if (end > crashk_res.start && end < crashk_res.end)
> +		end = min(end, crashk_res.start);
> +#endif
> +	
> +	if (start < end)
> +		add_active_range(nid, __pa(start) >> PAGE_SHIFT,
> +			__pa(end) >> PAGE_SHIFT);
>  	return 0;
>  }
> -#endif /* CONFIG_VIRTUAL_MEM_MAP */
>  
>  static int __init
>  count_reserved_pages (u64 start, u64 end, void *arg)
> diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.19-rc5-clean/include/asm-ia64/meminit.h linux-2.6.19-rc5-register_all_memory/include/asm-ia64/meminit.h
> --- linux-2.6.19-rc5-clean/include/asm-ia64/meminit.h	2006-11-08 02:24:20.000000000 +0000
> +++ linux-2.6.19-rc5-register_all_memory/include/asm-ia64/meminit.h	2006-11-16 15:29:31.000000000 +0000
> @@ -50,12 +50,13 @@ extern void efi_memmap_init(unsigned lon
>  
>  #define IGNORE_PFN0	1	/* XXX fix me: ignore pfn 0 until TLB miss handler is updated... */
>  
> +extern int register_active_ranges (u64 start, u64 end, void *arg);
> +
>  #ifdef CONFIG_VIRTUAL_MEM_MAP
>  # define LARGE_GAP	0x40000000 /* Use virtual mem map if hole is > than this */
>    extern unsigned long vmalloc_end;
>    extern struct page *vmem_map;
>    extern int find_largest_hole (u64 start, u64 end, void *arg);
> -  extern int register_active_ranges (u64 start, u64 end, void *arg);
>    extern int create_mem_map_page_table (u64 start, u64 end, void *arg);
>    extern int vmemmap_find_next_valid_pfn(int, int);
>  #else
> 
-- 
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