前面分析了memblock算法、内核页表的建立、内存管理框架的构建，这些都是x86处理的setup_arch()函数里面初始化的，因地制宜，具有明显处理器的特征。而start_kernel()接下来的初始化则是linux通用的内存管理算法框架了。

build_all_zonelists()用来初始化内存分配器使用的存储节点中的管理区链表，是为内存管理算法（伙伴管理算法）做准备工作的。具体实现：

【file：/mm/page_alloc.c】
/*
 * Called with zonelists_mutex held always
 * unless system_state == SYSTEM_BOOTING.
 */
void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
{
    set_zonelist_order();
 
    if (system_state == SYSTEM_BOOTING) {
        __build_all_zonelists(NULL);
        mminit_verify_zonelist();
        cpuset_init_current_mems_allowed();
    } else {
#ifdef CONFIG_MEMORY_HOTPLUG
        if (zone)
            setup_zone_pageset(zone);
#endif
        /* we have to stop all cpus to guarantee there is no user
           of zonelist */
        stop_machine(__build_all_zonelists, pgdat, NULL);
        /* cpuset refresh routine should be here */
    }
    vm_total_pages = nr_free_pagecache_pages();
    /*
     * Disable grouping by mobility if the number of pages in the
     * system is too low to allow the mechanism to work. It would be
     * more accurate, but expensive to check per-zone. This check is
     * made on memory-hotadd so a system can start with mobility
     * disabled and enable it later
     */
    if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
        page_group_by_mobility_disabled = 1;
    else
        page_group_by_mobility_disabled = 0;
 
    printk("Built %i zonelists in %s order, mobility grouping %s. "
        "Total pages: %ld\n",
            nr_online_nodes,
            zonelist_order_name[current_zonelist_order],
            page_group_by_mobility_disabled ? "off" : "on",
            vm_total_pages);
#ifdef CONFIG_NUMA
    printk("Policy zone: %s\n", zone_names[policy_zone]);
#endif
}

首先看到set_zonelist_order()：

【file：/mm/page_alloc.c】
static void set_zonelist_order(void)
{
    current_zonelist_order = ZONELIST_ORDER_ZONE;
}

此处用于设置zonelist的顺序，ZONELIST_ORDER_ZONE用于表示顺序(-zonetype, [node] distance)，另外还有ZONELIST_ORDER_NODE表示顺序([node] distance, -zonetype)。但其仅限于对NUMA环境存在区别，非NUMA环境则毫无差异。

如果系统状态system_state为SYSTEM_BOOTING，系统状态只有在start_kernel执行到最后一个函数rest_init后，才会进入SYSTEM_RUNNING，于是初始化时将会接着是__build_all_zonelists()函数:

【file：/mm/page_alloc.c】
/* return values int ....just for stop_machine() */
static int __build_all_zonelists(void *data)
{
    int nid;
    int cpu;
    pg_data_t *self = data;
 
#ifdef CONFIG_NUMA
    memset(node_load, 0, sizeof(node_load));
#endif
 
    if (self && !node_online(self->node_id)) {
        build_zonelists(self);
        build_zonelist_cache(self);
    }
 
    for_each_online_node(nid) {
        pg_data_t *pgdat = NODE_DATA(nid);
 
        build_zonelists(pgdat);
        build_zonelist_cache(pgdat);
    }
 
    /*
     * Initialize the boot_pagesets that are going to be used
     * for bootstrapping processors. The real pagesets for
     * each zone will be allocated later when the per cpu
     * allocator is available.
     *
     * boot_pagesets are used also for bootstrapping offline
     * cpus if the system is already booted because the pagesets
     * are needed to initialize allocators on a specific cpu too.
     * F.e. the percpu allocator needs the page allocator which
     * needs the percpu allocator in order to allocate its pagesets
     * (a chicken-egg dilemma).
     */
    for_each_possible_cpu(cpu) {
        setup_pageset(&per_cpu(boot_pageset, cpu), 0);
 
#ifdef CONFIG_HAVE_MEMORYLESS_NODES
        /*
         * We now know the "local memory node" for each node--
         * i.e., the node of the first zone in the generic zonelist.
         * Set