Re: [PATCH v2 2/4] mm/sparse: introduce alloc_usemap_and_memmap

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

On Tue, 20 Aug 2013 14:54:54 +0800 Wanpeng Li <liwanp@linux.vnet.ibm.com> wrote:

> v1 -> v2:
>  * add comments to describe alloc_usemap_and_memmap 
> 
> After commit 9bdac91424075("sparsemem: Put mem map for one node together."),
> vmemmap for one node will be allocated together, its logic is similar as
> memory allocation for pageblock flags. This patch introduce alloc_usemap_and_memmap
> to extract the same logic of memory alloction for pageblock flags and vmemmap.
> 

9bdac91424075 was written by Yinghai.  He is an excellent reviewer, as
long as people remember to cc him!

> ---
>  mm/sparse.c | 140 ++++++++++++++++++++++++++++--------------------------------
>  1 file changed, 66 insertions(+), 74 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 308d503..d27db9b 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -439,6 +439,14 @@ static void __init sparse_early_mem_maps_alloc_node(struct page **map_map,
>  					 map_count, nodeid);
>  }
>  #else
> +
> +static void __init sparse_early_mem_maps_alloc_node(struct page **map_map,
> +				unsigned long pnum_begin,
> +				unsigned long pnum_end,
> +				unsigned long map_count, int nodeid)
> +{
> +}
> +
>  static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
>  {
>  	struct page *map;
> @@ -460,6 +468,62 @@ void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
>  {
>  }
>  
> +/**
> + *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
> + *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
> + *  @use_map: true if memory allocated for pageblock flags, otherwise false
> + */
> +static void alloc_usemap_and_memmap(unsigned long **map, bool use_map)
> +{
> +	unsigned long pnum;
> +	unsigned long map_count;
> +	int nodeid_begin = 0;
> +	unsigned long pnum_begin = 0;
> +
> +	for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
> +		struct mem_section *ms;
> +
> +		if (!present_section_nr(pnum))
> +			continue;
> +		ms = __nr_to_section(pnum);
> +		nodeid_begin = sparse_early_nid(ms);
> +		pnum_begin = pnum;
> +		break;
> +	}
> +	map_count = 1;
> +	for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
> +		struct mem_section *ms;
> +		int nodeid;
> +
> +		if (!present_section_nr(pnum))
> +			continue;
> +		ms = __nr_to_section(pnum);
> +		nodeid = sparse_early_nid(ms);
> +		if (nodeid == nodeid_begin) {
> +			map_count++;
> +			continue;
> +		}
> +		/* ok, we need to take cake of from pnum_begin to pnum - 1*/
> +		if (use_map)
> +			sparse_early_usemaps_alloc_node(map, pnum_begin, pnum,
> +						 map_count, nodeid_begin);
> +		else
> +			sparse_early_mem_maps_alloc_node((struct page **)map,
> +				pnum_begin, pnum, map_count, nodeid_begin);
> +		/* new start, update count etc*/
> +		nodeid_begin = nodeid;
> +		pnum_begin = pnum;
> +		map_count = 1;
> +	}
> +	/* ok, last chunk */
> +	if (use_map)
> +		sparse_early_usemaps_alloc_node(map, pnum_begin,
> +				NR_MEM_SECTIONS, map_count, nodeid_begin);
> +	else
> +		sparse_early_mem_maps_alloc_node((struct page **)map,
> +			pnum_begin, NR_MEM_SECTIONS, map_count, nodeid_begin);
> +}
> +
>  /*
>   * Allocate the accumulated non-linear sections, allocate a mem_map
>   * for each and record the physical to section mapping.
> @@ -471,11 +535,7 @@ void __init sparse_init(void)
>  	unsigned long *usemap;
>  	unsigned long **usemap_map;
>  	int size;
> -	int nodeid_begin = 0;
> -	unsigned long pnum_begin = 0;
> -	unsigned long usemap_count;
>  #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
> -	unsigned long map_count;
>  	int size2;
>  	struct page **map_map;
>  #endif
> @@ -501,82 +561,14 @@ void __init sparse_init(void)
>  	usemap_map = alloc_bootmem(size);
>  	if (!usemap_map)
>  		panic("can not allocate usemap_map\n");
> -
> -	for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
> -		struct mem_section *ms;
> -
> -		if (!present_section_nr(pnum))
> -			continue;
> -		ms = __nr_to_section(pnum);
> -		nodeid_begin = sparse_early_nid(ms);
> -		pnum_begin = pnum;
> -		break;
> -	}
> -	usemap_count = 1;
> -	for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
> -		struct mem_section *ms;
> -		int nodeid;
> -
> -		if (!present_section_nr(pnum))
> -			continue;
> -		ms = __nr_to_section(pnum);
> -		nodeid = sparse_early_nid(ms);
> -		if (nodeid == nodeid_begin) {
> -			usemap_count++;
> -			continue;
> -		}
> -		/* ok, we need to take cake of from pnum_begin to pnum - 1*/
> -		sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, pnum,
> -						 usemap_count, nodeid_begin);
> -		/* new start, update count etc*/
> -		nodeid_begin = nodeid;
> -		pnum_begin = pnum;
> -		usemap_count = 1;
> -	}
> -	/* ok, last chunk */
> -	sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, NR_MEM_SECTIONS,
> -					 usemap_count, nodeid_begin);
> +	alloc_usemap_and_memmap(usemap_map, true);
>  
>  #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
>  	size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
>  	map_map = alloc_bootmem(size2);
>  	if (!map_map)
>  		panic("can not allocate map_map\n");
> -
> -	for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
> -		struct mem_section *ms;
> -
> -		if (!present_section_nr(pnum))
> -			continue;
> -		ms = __nr_to_section(pnum);
> -		nodeid_begin = sparse_early_nid(ms);
> -		pnum_begin = pnum;
> -		break;
> -	}
> -	map_count = 1;
> -	for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
> -		struct mem_section *ms;
> -		int nodeid;
> -
> -		if (!present_section_nr(pnum))
> -			continue;
> -		ms = __nr_to_section(pnum);
> -		nodeid = sparse_early_nid(ms);
> -		if (nodeid == nodeid_begin) {
> -			map_count++;
> -			continue;
> -		}
> -		/* ok, we need to take cake of from pnum_begin to pnum - 1*/
> -		sparse_early_mem_maps_alloc_node(map_map, pnum_begin, pnum,
> -						 map_count, nodeid_begin);
> -		/* new start, update count etc*/
> -		nodeid_begin = nodeid;
> -		pnum_begin = pnum;
> -		map_count = 1;
> -	}
> -	/* ok, last chunk */
> -	sparse_early_mem_maps_alloc_node(map_map, pnum_begin, NR_MEM_SECTIONS,
> -					 map_count, nodeid_begin);
> +	alloc_usemap_and_memmap((unsigned long **)map_map, false);
>  #endif
>  
>  	for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
> -- 
> 1.8.1.2

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