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alistair23-linux/mm/sparse.c

86 lines
2.0 KiB
C

/*
* sparse memory mappings.
*/
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/bootmem.h>
#include <linux/module.h>
#include <asm/dma.h>
/*
* Permanent SPARSEMEM data:
*
* 1) mem_section - memory sections, mem_map's for valid memory
*/
struct mem_section mem_section[NR_MEM_SECTIONS];
EXPORT_SYMBOL(mem_section);
/* Record a memory area against a node. */
void memory_present(int nid, unsigned long start, unsigned long end)
{
unsigned long pfn;
start &= PAGE_SECTION_MASK;
for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
unsigned long section = pfn_to_section_nr(pfn);
if (!mem_section[section].section_mem_map)
mem_section[section].section_mem_map = (void *) -1;
}
}
/*
* Only used by the i386 NUMA architecures, but relatively
* generic code.
*/
unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long pfn;
unsigned long nr_pages = 0;
for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
if (nid != early_pfn_to_nid(pfn))
continue;
if (pfn_valid(pfn))
nr_pages += PAGES_PER_SECTION;
}
return nr_pages * sizeof(struct page);
}
/*
* Allocate the accumulated non-linear sections, allocate a mem_map
* for each and record the physical to section mapping.
*/
void sparse_init(void)
{
unsigned long pnum;
struct page *map;
int nid;
for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
if (!mem_section[pnum].section_mem_map)
continue;
nid = early_pfn_to_nid(section_nr_to_pfn(pnum));
map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
if (!map)
map = alloc_bootmem_node(NODE_DATA(nid),
sizeof(struct page) * PAGES_PER_SECTION);
if (!map) {
mem_section[pnum].section_mem_map = 0;
continue;
}
/*
* Subtle, we encode the real pfn into the mem_map such that
* the identity pfn - section_mem_map will return the actual
* physical page frame number.
*/
mem_section[pnum].section_mem_map = map -
section_nr_to_pfn(pnum);
}
}