Re: [PATCH] mm: show node to memory section relationship with symlinks in sysfs

[Yasunori Goto]

> +#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
> +int register_mem_sect_under_node(struct memory_block *mem_blk)
        :

I think this patch is convenience even when memory hotplug is disabled.
CONFIG_SPARSEMEM seems better than CONFIG_MEMORY_HOTPLUG_SPARSE.


> +int register_mem_sect_under_node(struct memory_block *mem_blk)
> +{
> +	unsigned int nid;
> +
> +	if (!mem_blk)
> +		return -EFAULT;
> +	nid = section_nr_to_nid(mem_blk->phys_index);

(snip)

> +#define section_nr_to_nid(section_nr) pfn_to_nid(section_nr_to_pfn(section_nr))
>  #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */

If the first page of the section is not valid, then this section_nr_to_nid()
doesn't return correct value.

I tested this patch. In my box, the start_pfn of node 1 is 1200400, but 
section_nr_to_pfn(mem_blk->phys_index) returns 1200000. As a result,
the section is linked to node 0.

Bye.
-- 
Yasunori Goto 


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