Re: [PATCH v3 3/5] page_alloc: Introduce zone_movable_limit[] to keep movable limit for nodes

[Tang Chen <tangchen@cn.fujitsu.com>]

On 12/11/2012 11:07 AM, Jianguo Wu wrote:
> On 2012/12/11 10:33, 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>
>> Signed-off-by: Jiang Liu<jiang.liu@huawei.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 |   77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 files changed, 77 insertions(+), 0 deletions(-)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index 1c91d16..4853619 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;
>> @@ -4340,6 +4341,77 @@ 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;
>> +
>> +#ifdef CONFIG_ZONE_DMA
>> +		/* Skip DMA memory. */
>> +		if (start_pfn<  arch_zone_highest_possible_pfn[ZONE_DMA])
>> +			start_pfn = arch_zone_highest_possible_pfn[ZONE_DMA];
>> +#endif
>> +
>> +#ifdef CONFIG_ZONE_DMA32
>> +		/* Skip DMA32 memory. */
>> +		if (start_pfn<  arch_zone_highest_possible_pfn[ZONE_DMA32])
>> +			start_pfn = arch_zone_highest_possible_pfn[ZONE_DMA32];
>> +#endif
>> +
>> +#ifdef CONFIG_HIGHMEM
>> +		/* Skip lowmem if ZONE_MOVABLE is highmem. */
>> +		if (zone_movable_is_highmem()&&
>
> Hi Tang,
>
> I think zone_movable_is_highmem() is not work correctly here.
> 	sanitize_zone_movable_limit
> 		zone_movable_is_highmem<--using movable_zone here
> 	find_zone_movable_pfns_for_nodes
> 		find_usable_zone_for_movable<--movable_zone is specified here
>
> I think Jiang Liu's patch works fine for highmem, please refer to:
> http://marc.info/?l=linux-mm&m=135476085816087&w=2

Hi Wu,

Yes, I forgot movable_zone think. Thanks for reminding me. :)

But Liu's patch you just mentioned, I didn't use it because I
don't think we should skip kernelcore when movablecore_map is specified.
If these 2 options are not conflict, we should satisfy them both. :)

Of course, I also think Liu's suggestion is wonderful. But I think we
need more discussion on it. :)

I'll fix it soon.
Thanks. :)

>
> Thanks,
> Jianguo Wu
>
>> +		    start_pfn<  arch_zone_lowest_possible_pfn[ZONE_HIGHMEM])
>> +			start_pfn = arch_zone_lowest_possible_pfn[ZONE_HIGHMEM];
>> +#endif
>> +
>> +		if (start_pfn>= end_pfn)
>> +			continue;
>> +
>> +		while (map_pos<  movablecore_map.nr_map) {
>> +			if (end_pfn<= movablecore_map.map[map_pos].start_pfn)
>> +				break;
>> +
>> +			if (start_pfn>= movablecore_map.map[map_pos].end_pfn) {
>> +				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_pfn);
>> +
>> +			break;
>> +		}
>> +	}
>> +}
>> +
>>   #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
>>   static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
>>   					unsigned long zone_type,
>> @@ -4358,6 +4430,10 @@ 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,
>> @@ -4923,6 +4999,7 @@ 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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