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

[Jiang Liu <jiang.liu@huawei.com>]

On 2012-12-11 19:28, Simon Jeons wrote:
> On Tue, 2012-12-11 at 11:32 +0800, Tang Chen wrote:
>> 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.
> 
> What's the difference between zone_movable_limit[nid] and
> zone_movable_pfn[nid]?
zone_movable_limit[] is a temporary storage for zone_moveable_pfn[].
It's used to handle a special case if user specifies both movablecore_map
and movablecore/kernelcore on the kernel command line. 

> 
>>>>
>>>> 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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> 
> 
> 
> .
> 


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