create_zone_bm_rtree

Name:reate_zone_bm_rtree - Create a radix tree for one zone.* Allocated the mem_zone_bm_rtree structure and initializes it.* This function also allocated and builds the radix tree for the* zone.

Proto:static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask, int safe_needed, struct chain_allocator *ca, unsigned long start, unsigned long end)

Type:struct mem_zone_bm_rtree

Parameter:

Type	Parameter	Name
gfp_t	gfp_mask
int	safe_needed
struct chain_allocator *	ca
unsigned long	start
unsigned long	end

508

pages = end - start

509

zone = chain_alloc(ca, sizeof(structmem_zone_bm_rtree))

510

If Not zone Then Return NULL

513

Initialization list head

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Initialization list head

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Zone start page frame = start

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Zone end page frame + 1 = end

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nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK)

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When i < nr_blocks cycle

520

If add_rtree_block - Add a new leave node to the radix tree.* The leave nodes need to be allocated in order to keep the leaves* linked list in order. This is guaranteed by the zone->blocks* counter. Then

521

free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR)

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Return NULL

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Return zone

**Caller**
Name	Describe
memory_bm_create	memory_bm_create - Allocate memory for a memory bitmap.

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