zone_size_init

[분석 기준] 

 kernel version : linux kernel 4.16

 architecture : aarch64 (arm64)

memblock_init() 에서 zone_sizes_init() 함수를 분석한다. 분석 기준은 CONFIG_NUMA가 설정되어 있다는 가정하에 설정한다.

zone_sizes_init() 함수에 전달되는 min, max는 DRAM의 memblock 시작과 끝 주소를 전달한다.

#ifdef CONFIG_NUMA // IMRT >> yes!
 
static void __init zone_sizes_init(unsigned long min, unsigned long max)
{
    unsigned long max_zone_pfns[MAX_NR_ZONES]  = {0};
 
    if (IS_ENABLED(CONFIG_ZONE_DMA32))
        max_zone_pfns[ZONE_DMA32] = PFN_DOWN(max_zone_dma_phys());
    // IMRT >> DMA32 빼고 나머지 전부 NORMAL
    max_zone_pfns[ZONE_NORMAL] = max;
 
    free_area_init_nodes(max_zone_pfns);
}
 

line 12 :

 NUMA 시스템인 경우 전체 노드에 대해 초기화를 해야하므로 free_area_init_nodes() 함수를 호출한다. CONFIG_NUMA가 설정되지 않은 경우에는 free_area_init_node() 함수가 호출되서 하나의 노드만을 초기화한다.

memblock_init()

  -> zone_sizes_init()

    -> free_area_init_nodes()

/**
 * free_area_init_nodes - Initialise all pg_data_t and zone data
 * @max_zone_pfn: an array of max PFNs for each zone
 *
 * This will call free_area_init_node() for each active node in the system.
 * Using the page ranges provided by memblock_set_node(), the size of each
 * zone in each node and their holes is calculated. If the maximum PFN
 * between two adjacent zones match, it is assumed that the zone is empty.
 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
 * starts where the previous one ended. For example, ZONE_DMA32 starts
 * at arch_max_dma_pfn.
 */
void __init free_area_init_nodes(unsigned long *max_zone_pfn)
{
    unsigned long start_pfn, end_pfn;
    int i, nid;
 
    /* Record where the zone boundaries are */
    memset(arch_zone_lowest_possible_pfn, 0,
                sizeof(arch_zone_lowest_possible_pfn));
    memset(arch_zone_highest_possible_pfn, 0,
                sizeof(arch_zone_highest_possible_pfn));
 
 
    start_pfn = find_min_pfn_with_active_regions();
 
    for (i = 0; i < MAX_NR_ZONES; i++) {
        if (i == ZONE_MOVABLE)
            continue;
 
        end_pfn = max(max_zone_pfn[i], start_pfn);
        arch_zone_lowest_possible_pfn[i] = start_pfn;
        arch_zone_highest_possible_pfn[i] = end_pfn;
 
        start_pfn = end_pfn;
    }
 
    /* Find the PFNs that ZONE_MOVABLE begins at in each node */
    memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
    find_zone_movable_pfns_for_nodes();
 
    /* Print out the zone ranges */
    pr_info("Zone ranges:\n");
    for (i = 0; i < MAX_NR_ZONES; i++) {
        if (i == ZONE_MOVABLE)
            continue;
        pr_info("  %-8s ", zone_names[i]);
        if (arch_zone_lowest_possible_pfn[i] ==
                arch_zone_highest_possible_pfn[i])
            pr_cont("empty\n");
        else
            pr_cont("[mem %#018Lx-%#018Lx]\n",
                (u64)arch_zone_lowest_possible_pfn[i]
                    << PAGE_SHIFT,
                ((u64)arch_zone_highest_possible_pfn[i]
                    << PAGE_SHIFT) - 1);
    }
 
    /* Print out the PFNs ZONE_MOVABLE begins at in each node */
    pr_info("Movable zone start for each node\n");
    for (i = 0; i < MAX_NUMNODES; i++) {
        if (zone_movable_pfn[i])
            pr_info("  Node %d: %#018Lx\n", i,
                   (u64)zone_movable_pfn[i] << PAGE_SHIFT);
    }
 
    /* Print out the early node map */
    pr_info("Early memory node ranges\n");
    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
        pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
            (u64)start_pfn << PAGE_SHIFT,
            ((u64)end_pfn << PAGE_SHIFT) - 1);
 
    /* Initialise every node */
    mminit_verify_pageflags_layout();
    setup_nr_node_ids();
    for_each_online_node(nid) {
        pg_data_t *pgdat = NODE_DATA(nid);
        free_area_init_node(nid, NULL,
                find_min_pfn_for_node(nid), NULL);
 
        /* Any memory on that node */
        if (pgdat->node_present_pages)
            node_set_state(nid, N_MEMORY);
        check_for_memory(pgdat, nid);
    }
    zero_resv_unavail();
}