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

[Jianguo Wu <wujianguo@huawei.com>]

On 2012/12/11 20:24, Simon Jeons wrote:

> On Tue, 2012-12-11 at 11:07 +0800, 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
>>
> 
> Hi Jiangguo and Chen,
> 
> - What's the meaning of zone_movable_is_highmem(), does it mean all zone
> highmem pages are zone movable pages or ....

Hi Simon,

zone_movable_is_highmem() means whether zone pages in ZONE_MOVABLE are taken from
highmem.

> - dmesg 
> 
>> 0.000000] Zone ranges:
>> [    0.000000]   DMA      [mem 0x00010000-0x00ffffff]
>> [    0.000000]   Normal   [mem 0x01000000-0x373fdfff]
>> [    0.000000]   HighMem  [mem 0x373fe000-0xb6cfffff]
>> [    0.000000] Movable zone start for each node
>> [    0.000000]   Node 0: 0x97800000
> 
> Why the start of zone movable is in the range of zone highmem, if all
> the pages of zone movable are from zone highmem? If the answer is yes, 

> zone movable and zone highmem are in the equal status or not?

The pages of zone_movable can be taken from zone_movalbe or zone_normal,
if we have highmem, then zone_movable will be taken from zone_highmem,
otherwise zone_movable will be taken from zone_normal.

you can refer to find_usable_zone_for_movable().

Thanks,
Jianguo Wu

> 
>> I think Jiang Liu's patch works fine for highmem, please refer to:
>> http://marc.info/?l=linux-mm&m=135476085816087&w=2
>>
>> 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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> 
> 
> 
> .
> 



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