Re: [PATCH v4 4/4] Use 2GB memory block size on large-memory x86-64 systems

[Ingo Molnar <mingo@kernel.org>]

* Yinghai Lu <yinghai@kernel.org> wrote:

> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -390,8 +390,14 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
>  	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
>  	sect_end_pfn += PAGES_PER_SECTION - 1;
>  	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
> -		int page_nid;
> +		int page_nid, scn_nr;
>  
> +		scn_nr = pfn_to_section_nr(pfn);
> +		if (!present_section_nr(scn_nr)) {
> +			pfn = round_down(pfn + PAGES_PER_SECTION,
> +					 PAGES_PER_SECTION) - 1;
> +			continue;
> +		}
>  		page_nid = get_nid_for_pfn(pfn);
>  		if (page_nid < 0)
>  			continue;
> @@ -426,10 +432,18 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
>  		return -ENOMEM;
>  	nodes_clear(*unlinked_nodes);
>  
> -	sect_start_pfn = section_nr_to_pfn(phys_index);
> -	sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
> +	sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
> +	sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
> +	sect_end_pfn += PAGES_PER_SECTION - 1;
>  	for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
> -		int nid;
> +		int nid, scn_nr;
> +
> +		scn_nr = pfn_to_section_nr(pfn);
> +		if (!present_section_nr(scn_nr)) {
> +			pfn = round_down(pfn + PAGES_PER_SECTION,
> +					 PAGES_PER_SECTION) - 1;
> +			continue;
> +		}

NAK due to lack of cleanliness: the two loops look almost identical - this sure 
can be factored out...

Thanks,

	Ingo