Re: [PATCH 1/2] mm/page_alloc.c: Implement an empty get_pfn_range_for_nid

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 06 Oct 2013 01:31:36 +0800 Zhang Yanfei <zhangyanfei.yes@gmail.com> wrote:

> From: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> 
> Implement an empty get_pfn_range_for_nid for !CONFIG_HAVE_MEMBLOCK_NODE_MAP,
> so that we could remove the #ifdef in free_area_init_node.
> 
> ...
>
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4566,6 +4566,11 @@ static unsigned long __meminit zone_absent_pages_in_node(int nid,
>  }
>  
>  #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
> +void __meminit get_pfn_range_for_nid(unsigned int nid,
> +			unsigned long *ignored, unsigned long *ignored)
> +{
> +}
> +
>  static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
>  					unsigned long zone_type,
>  					unsigned long node_start_pfn,
> @@ -4871,9 +4876,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
>  	pgdat->node_id = nid;
>  	pgdat->node_start_pfn = node_start_pfn;
>  	init_zone_allows_reclaim(nid);
> -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
>  	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
> -#endif
>  	calculate_node_totalpages(pgdat, start_pfn, end_pfn,
>  				  zones_size, zholes_size);

Dunno, really.  This will make the kernel a tiny bit larger by
generating an out-of-line empty function which nobody calls.  This
could be fixed by making this static inline, but it's strange to have
one version of get_pfn_range_for_nid() static inline and the other
global, uninlined.

Is it worth adding a few bytes to vmlinux just to make the source a little
tidier?

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