init_bootmem_node

初始化pg_data_t->bdtat结构体，

/*
 * node_bootmem_map is a map pointer - the bits represent all physical 
 * memory pages (including holes) on the node.
 */
typedef struct bootmem_data {
    unsigned long node_min_pfn;
    unsigned long node_low_pfn;
    void *node_bootmem_map;
    unsigned long last_end_off;
    unsigned long hint_idx;
    struct list_head list;
} bootmem_data_t;

将不同node的bdata添加到以bdata_list为首的链表。

标记所有的bitmap位为1。

unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,    unsigned long startpfn, unsigned long endpfn)
    -->init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
        -->link_bootmem(bdata);
        /*标记所有内存页框为1，已使用*/
        -->mapsize = bootmap_bytes(end - start);
        -->memset(bdata->node_bootmem_map, 0xff, mapsize);

/*
 * Called once to set up the allocator itself.
 */
static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
    unsigned long mapstart, unsigned long start, unsigned long end)
{
    unsigned long mapsize;

    mminit_validate_memmodel_limits(&start, &end);
    bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
    bdata->node_min_pfn = start;
    bdata->node_low_pfn = end;
    link_bootmem(bdata);

    /*
     * Initially all pages are reserved - setup_arch() has to
     * register free RAM areas explicitly.
     */
    mapsize = bootmap_bytes(end - start);
    memset(bdata->node_bootmem_map, 0xff, mapsize);

    bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx
",
        bdata - bootmem_node_data, start, mapstart, end, mapsize);

    return mapsize;
}