Re: [PATCH v2 3/5] page_alloc: Introduce zone_movable_limit[] to keep movable limit for nodes

[Jiang Liu <liuj97@gmail.com>]

On 11/23/2012 06:44 PM, Tang Chen wrote:
> This patch introduces a new array zone_movable_limit[] to store the
> ZONE_MOVABLE limit from movablecore_map boot option for all nodes.
> The function sanitize_zone_movable_limit() will find out to which
> node the ranges in movable_map.map[] belongs, and calculates the
> low boundary of ZONE_MOVABLE for each node.
> 
> Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
> Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> Tested-by: Lin Feng <linfeng@cn.fujitsu.com>
> ---
>  mm/page_alloc.c |   55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 55 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index fb5cf12..f23d76a 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -206,6 +206,7 @@ static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
>  static unsigned long __initdata required_kernelcore;
>  static unsigned long __initdata required_movablecore;
>  static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
> +static unsigned long __meminitdata zone_movable_limit[MAX_NUMNODES];
>  
>  /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
>  int movable_zone;
> @@ -4323,6 +4324,55 @@ static unsigned long __meminit zone_absent_pages_in_node(int nid,
>  	return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
>  }
>  
> +/**
> + * sanitize_zone_movable_limit - Sanitize the zone_movable_limit array.
> + *
> + * zone_movable_limit is initialized as 0. This function will try to get
> + * the first ZONE_MOVABLE pfn of each node from movablecore_map, and
> + * assigne them to zone_movable_limit.
> + * zone_movable_limit[nid] == 0 means no limit for the node.
> + *
> + * Note: Each range is represented as [start_pfn, end_pfn)
> + */
> +static void __meminit sanitize_zone_movable_limit(void)
> +{
> +	int map_pos = 0, i, nid;
> +	unsigned long start_pfn, end_pfn;
> +
> +	if (!movablecore_map.nr_map)
> +		return;
> +
> +	/* Iterate all ranges from minimum to maximum */
> +	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
> +		/*
> +		 * If we have found lowest pfn of ZONE_MOVABLE of the node
> +		 * specified by user, just go on to check next range.
> +		 */
> +		if (zone_movable_limit[nid])
> +			continue;
Need special handling of low memory here on systems with highmem, otherwise
it will cause us to configure both lowmem and highmem as movable_zone.

> +
> +		while (map_pos < movablecore_map.nr_map) {
> +			if (end_pfn <= movablecore_map.map[map_pos].start)
> +				break;
> +
> +			if (start_pfn >= movablecore_map.map[map_pos].end) {
> +				map_pos++;
> +				continue;
> +			}
> +
> +			/*
> +			 * The start_pfn of ZONE_MOVABLE is either the minimum
> +			 * pfn specified by movablecore_map, or 0, which means
> +			 * the node has no ZONE_MOVABLE.
> +			 */
> +			zone_movable_limit[nid] = max(start_pfn,
> +					movablecore_map.map[map_pos].start);
> +
> +			break;
> +		}
> +	}
> +}
> +
>  #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
>  static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
>  					unsigned long zone_type,
> @@ -4341,6 +4391,10 @@ static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
>  	return zholes_size[zone_type];
>  }
>  
> +static void __meminit sanitize_zone_movable_limit(void)
> +{
> +}
> +
>  #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
>  
>  static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
> @@ -4906,6 +4960,7 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
>  
>  	/* Find the PFNs that ZONE_MOVABLE begins at in each node */
>  	memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
> +	sanitize_zone_movable_limit();
>  	find_zone_movable_pfns_for_nodes();
>  
>  	/* Print out the zone ranges */
> 

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