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硬件:E500v2内核PowerPC ,linux版本:2.6.35
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3. 全部内存初始化完毕,可以用cache和buddy分配内存。
相关常量定义: 26 #define NODE_DATA(nid) (node_data[nid]) 782 extern struct pglist_data contig_page_data; 783 #define NODE_DATA(nid) (&contig_page_data) 784 #define NODE_MEM_MAP(nid) mem_map4714 struct pglist_data __refdata contig_page_data = {4716 .bdata = &bootmem_node_data[0]4718 };
38 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;//
MAX_NUMNODES=0 31 typedef
struct bootmem_data {
32 unsigned long node_min_pfn;
33 unsigned long node_low_pfn;
34 void *node_bootmem_map;
35 unsigned long last_end_off;
36 unsigned long hint_idx;
37 struct list_head list;
38 } bootmem_data_t;
609 typedef
struct pglist_data {
610 struct zone node_zones[MAX_NR_ZONES];
611 struct zonelist node_zonelists[MAX_ZONELISTS];
612 int nr_zones;
613 #ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
614 struct page *node_mem_map;
615 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
616 struct page_cgroup *node_page_cgroup;
617 #endif
618 #endif
619 #ifndef CONFIG_NO_BOOTMEM
620 struct bootmem_data *bdata;
621 #endif
622 #ifdef CONFIG_MEMORY_HOTPLUG
623 /*
624 * Must be held any time you expect node_start_pfn, node_present_pages
625 * or node_spanned_pages stay constant. Holding this will also
626 * guarantee that any pfn_valid() stays that way.
627 *
628 * Nests above zone->lock and zone->size_seqlock.
629 */
630 spinlock_t node_size_lock;
631 #endif
632 unsigned long node_start_pfn;
633 unsigned long node_present_pages; /* total number of physical pages */
634 unsigned long node_spanned_pages; /* total size of physical page
635 range, including holes */
636 int node_id;
637 wait_queue_head_t kswapd_wait;
638 struct task_struct *kswapd;
639 int kswapd_max_order;
640 } pg_data_t;
576
struct zonelist {
577 struct zonelist_cache *zlcache_ptr; // NULL or &zlcache = NULL
578 struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];//MAX_ZONES_PER_ZONELIST=4
579 #ifdef CONFIG_NUMA
580 struct zonelist_cache zlcache; // optional ...
581 #endif
582 };
554
struct zoneref {
555 struct zone *zone; /* Pointer to actual zone */
556 int zone_idx; /* zone_idx(zoneref->zone) */
557 };
内存初始化步骤:
1. start_kernel---->setup_arch->pageing_init
|-->setup_per_cpu_areas
|-->build_all_zonelists
|-->mem_init
-->setup_per_cpu_pageset
start_kernel---->setup_arch->pageing_init代码如下:
- 273 /*
-
274 * paging_init() sets up the page tables - in fact we've already done this.
-
275 */
-
276 void __init paging_init(void)
-
277 {
-
278 unsigned long total_ram = memblock_phys_mem_size();
-
279 phys_addr_t top_of_ram = memblock_end_of_DRAM();
-
280 unsigned long max_zone_pfns[MAX_NR_ZONES];
-
281
-
282 #ifdef CONFIG_PPC32
-
283 unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
-
284 unsigned long end = __fix_to_virt(FIX_HOLE);
-
285
-
286 for (; v < end; v += PAGE_SIZE)
-
287 map_page(v, 0, 0); /* XXX gross */
-
288 #endif
-
289
-
290 #ifdef CONFIG_HIGHMEM
-
291 map_page(PKMAP_BASE, 0, 0); /* XXX gross */
-
292 pkmap_page_table = virt_to_kpte(PKMAP_BASE);
-
293
-
294 kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
-
295 kmap_prot = PAGE_KERNEL;
-
296 #endif /* CONFIG_HIGHMEM */
-
297
-
298 printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%lx\n",
-
299 (unsigned long long)top_of_ram, total_ram);
-
300 printk(KERN_DEBUG "Memory hole size: %ldMB\n",
-
301 (long int)((top_of_ram - total_ram) >> 20));
-
302 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
-
303 #ifdef CONFIG_HIGHMEM
-
304 max_zone_pfns[ZONE_DMA] = lowmem_end_addr >> PAGE_SHIFT;
-
305 max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT;
-
306 #else
-
307 max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
-
308 #endif
-
309 free_area_init_nodes(max_zone_pfns);
-
310
-
311 mark_nonram_nosave();
-
312 }
-
313 #endif /* ! CONFIG_NEED_MULTIPLE_NODES */
378-280:计算整个内存的大小,此处为:0x8000 0000
282-288: 映射临时映射空间,也称固定映射
290-196:映射高端内存PTE
307:最为重要,该函数清空bitmap区,把所有页设为保留。
|-->setup_per_cpu_areas
该函数当非SMP情况使用,此处为空。
|-->build_all_zonelists
函数代码为:
- 3031 void build_all_zonelists(void *data)
-
3032 {
-
3033 set_zonelist_order();
-
3034
-
3035 if (system_state == SYSTEM_BOOTING) {
-
3036 __build_all_zonelists(NULL);
-
3037 mminit_verify_zonelist();
-
3038 cpuset_init_current_mems_allowed();
-
3039 } else {
-
3040 /* we have to stop all cpus to guarantee there is no user
-
3041 of zonelist */
-
3042 stop_machine(__build_all_zonelists, data, NULL);
-
3043 /* cpuset refresh routine should be here */
-
3044 }
-
3045 vm_total_pages = nr_free_pagecache_pages();
-
3046 /*
-
3047 * Disable grouping by mobility if the number of pages in the
-
3048 * system is too low to allow the mechanism to work. It would be
-
3049 * more accurate, but expensive to check per-zone. This check is
-
3050 * made on memory-hotadd so a system can start with mobility
-
3051 * disabled and enable it later
-
3052 */
-
3053 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
-
3054 page_group_by_mobility_disabled = 1;
-
3055 else
-
3056 page_group_by_mobility_disabled = 0;
-
3057
-
3058 printk("Built %i zonelists in %s order, mobility grouping %s. "
-
3059 "Total pages: %ld\n",
-
3060 nr_online_nodes,
-
3061 zonelist_order_name[current_zonelist_order],
-
3062 page_group_by_mobility_disabled ? "off" : "on",
-
3063 vm_total_pages);
-
3064 #ifdef CONFIG_NUMA
-
3065 printk("Policy zone: %s\n", zone_names[policy_zone]);
-
3066 #endif
-
3067 }
函数中:__build_all_zonelists
函数建立了zone链表,当一个zone不能满足当前分配时会根据此链表来找到下一个可以分配的zone。当有多个节点时,建立后的结果为:
b2->b1->b0->a2->a1->a0 (b=node1,a=node0,2=highmem, 1=normal, 0=dma)
|-->mem_init函数代码为:
- 526 static void __init mm_init(void)
-
527 {
-
532 page_cgroup_init_flatmem();
-
533 mem_init();
-
534 kmem_cache_init();
-
535 pgtable_cache_init();
-
536 vmalloc_init();
-
537 }
532:为空函数
533:函数执行完毕后, mem_init_done = 1;即buddy系统分配内存内可以使用了。
534:用来初始化slab和cache,函数执行完后slab可以使用,可以分配少于1页的内存了。
535:空函数
536:vmalloc空间可以正常使用了。
整个内存的布局为:
Kernel virtual memory layout:
* 0xfffcf000..0xfffff000 : fixmap
* 0xff800000..0xffc00000 : highmem PTEs
* 0xff7d8000..0xff800000 : early ioremap
* 0xf1000000..0xff7d8000 : vmalloc & ioremap
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