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

[Tang Chen]

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@xxxxxxxxxxxxxx>
> > Signed-off-by: Jiang Liu<jiang.liu@xxxxxxxxxx>
> > Reviewed-by: Wen Congyang<wency@xxxxxxxxxxxxxx>
> > Reviewed-by: Lai Jiangshan<laijs@xxxxxxxxxxxxxx>
> > Tested-by: Lin Feng<linfeng@xxxxxxxxxxxxxx>
> > ---
> >   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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