drivers/base/node.c

   1 /*
   2  * Basic Node interface support
   3  */
   4
   5 #include <linux/module.h>
   6 #include <linux/init.h>
   7 #include <linux/mm.h>
   8 #include <linux/memory.h>
   9 #include <linux/vmstat.h>
  10 #include <linux/node.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/compaction.h>
  13 #include <linux/cpumask.h>
  14 #include <linux/topology.h>
  15 #include <linux/nodemask.h>
  16 #include <linux/cpu.h>
  17 #include <linux/device.h>
  18 #include <linux/swap.h>
  19 #include <linux/slab.h>
  20
  21 static struct bus_type node_subsys = {
  22         .name = "node",
  23         .dev_name = "node",
  24 };
  25
  26
  27 static ssize_t node_read_cpumap(struct device *dev, int type, char *buf)
  28 {
  29         struct node *node_dev = to_node(dev);
  30         const struct cpumask *mask = cpumask_of_node(node_dev->dev.id);
  31         int len;
  32
  33         /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
  34         BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
  35
  36         len = type?
  37                 cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
  38                 cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
  39         buf[len++] = '\n';
  40         buf[len] = '\0';
  41         return len;
  42 }
  43
  44 static inline ssize_t node_read_cpumask(struct device *dev,
  45                                 struct device_attribute *attr, char *buf)
  46 {
  47         return node_read_cpumap(dev, 0, buf);
  48 }
  49 static inline ssize_t node_read_cpulist(struct device *dev,
  50                                 struct device_attribute *attr, char *buf)
  51 {
  52         return node_read_cpumap(dev, 1, buf);
  53 }
  54
  55 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
  56 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
  57
  58 #define K(x) ((x) << (PAGE_SHIFT - 10))
  59 static ssize_t node_read_meminfo(struct device *dev,
  60                         struct device_attribute *attr, char *buf)
  61 {
  62         int n;
  63         int nid = dev->id;
  64         struct sysinfo i;
  65
  66         si_meminfo_node(&i, nid);
  67         n = sprintf(buf,
  68                        "Node %d MemTotal:       %8lu kB\n"
  69                        "Node %d MemFree:        %8lu kB\n"
  70                        "Node %d MemUsed:        %8lu kB\n"
  71                        "Node %d Active:         %8lu kB\n"
  72                        "Node %d Inactive:       %8lu kB\n"
  73                        "Node %d Active(anon):   %8lu kB\n"
  74                        "Node %d Inactive(anon): %8lu kB\n"
  75                        "Node %d Active(file):   %8lu kB\n"
  76                        "Node %d Inactive(file): %8lu kB\n"
  77                        "Node %d Unevictable:    %8lu kB\n"
  78                        "Node %d Mlocked:        %8lu kB\n",
  79                        nid, K(i.totalram),
  80                        nid, K(i.freeram),
  81                        nid, K(i.totalram - i.freeram),
  82                        nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
  83                                 node_page_state(nid, NR_ACTIVE_FILE)),
  84                        nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
  85                                 node_page_state(nid, NR_INACTIVE_FILE)),
  86                        nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
  87                        nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
  88                        nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
  89                        nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
  90                        nid, K(node_page_state(nid, NR_UNEVICTABLE)),
  91                        nid, K(node_page_state(nid, NR_MLOCK)));
  92
  93 #ifdef CONFIG_HIGHMEM
  94         n += sprintf(buf + n,
  95                        "Node %d HighTotal:      %8lu kB\n"
  96                        "Node %d HighFree:       %8lu kB\n"
  97                        "Node %d LowTotal:       %8lu kB\n"
  98                        "Node %d LowFree:        %8lu kB\n",
  99                        nid, K(i.totalhigh),
 100                        nid, K(i.freehigh),
 101                        nid, K(i.totalram - i.totalhigh),
 102                        nid, K(i.freeram - i.freehigh));
 103 #endif
 104         n += sprintf(buf + n,
 105                        "Node %d Dirty:          %8lu kB\n"
 106                        "Node %d Writeback:      %8lu kB\n"
 107                        "Node %d FilePages:      %8lu kB\n"
 108                        "Node %d Mapped:         %8lu kB\n"
 109                        "Node %d AnonPages:      %8lu kB\n"
 110                        "Node %d Shmem:          %8lu kB\n"
 111                        "Node %d KernelStack:    %8lu kB\n"
 112                        "Node %d PageTables:     %8lu kB\n"
 113                        "Node %d NFS_Unstable:   %8lu kB\n"
 114                        "Node %d Bounce:         %8lu kB\n"
 115                        "Node %d WritebackTmp:   %8lu kB\n"
 116                        "Node %d Slab:           %8lu kB\n"
 117                        "Node %d SReclaimable:   %8lu kB\n"
 118                        "Node %d SUnreclaim:     %8lu kB\n"
 119 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 120                        "Node %d AnonHugePages:  %8lu kB\n"
 121 #endif
 122                         ,
 123                        nid, K(node_page_state(nid, NR_FILE_DIRTY)),
 124                        nid, K(node_page_state(nid, NR_WRITEBACK)),
 125                        nid, K(node_page_state(nid, NR_FILE_PAGES)),
 126                        nid, K(node_page_state(nid, NR_FILE_MAPPED)),
 127 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 128                        nid, K(node_page_state(nid, NR_ANON_PAGES)
 129                         + node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
 130                         HPAGE_PMD_NR),
 131 #else
 132                        nid, K(node_page_state(nid, NR_ANON_PAGES)),
 133 #endif
 134                        nid, K(node_page_state(nid, NR_SHMEM)),
 135                        nid, node_page_state(nid, NR_KERNEL_STACK) *
 136                                 THREAD_SIZE / 1024,
 137                        nid, K(node_page_state(nid, NR_PAGETABLE)),
 138                        nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
 139                        nid, K(node_page_state(nid, NR_BOUNCE)),
 140                        nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
 141                        nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
 142                                 node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
 143                        nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
 144 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 145                        nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
 146                         , nid,
 147                         K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
 148                         HPAGE_PMD_NR));
 149 #else
 150                        nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
 151 #endif
 152         n += hugetlb_report_node_meminfo(nid, buf + n);
 153         return n;
 154 }
 155
 156 #undef K
 157 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 158
 159 static ssize_t node_read_numastat(struct device *dev,
 160                                 struct device_attribute *attr, char *buf)
 161 {
 162         return sprintf(buf,
 163                        "numa_hit %lu\n"
 164                        "numa_miss %lu\n"
 165                        "numa_foreign %lu\n"
 166                        "interleave_hit %lu\n"
 167                        "local_node %lu\n"
 168                        "other_node %lu\n",
 169                        node_page_state(dev->id, NUMA_HIT),
 170                        node_page_state(dev->id, NUMA_MISS),
 171                        node_page_state(dev->id, NUMA_FOREIGN),
 172                        node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
 173                        node_page_state(dev->id, NUMA_LOCAL),
 174                        node_page_state(dev->id, NUMA_OTHER));
 175 }
 176 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 177
 178 static ssize_t node_read_vmstat(struct device *dev,
 179                                 struct device_attribute *attr, char *buf)
 180 {
 181         int nid = dev->id;
 182         int i;
 183         int n = 0;
 184
 185         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 186                 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
 187                              node_page_state(nid, i));
 188
 189         return n;
 190 }
 191 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 192
 193 static ssize_t node_read_distance(struct device *dev,
 194                         struct device_attribute *attr, char * buf)
 195 {
 196         int nid = dev->id;
 197         int len = 0;
 198         int i;
 199
 200         /*
 201          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 202          * at the most (distance + space or newline).
 203          */
 204         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 205
 206         for_each_online_node(i)
 207                 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 208
 209         len += sprintf(buf + len, "\n");
 210         return len;
 211 }
 212 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 213
 214 #ifdef CONFIG_HUGETLBFS
 215 /*
 216  * hugetlbfs per node attributes registration interface:
 217  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 218  * it will register its per node attributes for all online nodes with
 219  * memory.  It will also call register_hugetlbfs_with_node(), below, to
 220  * register its attribute registration functions with this node driver.
 221  * Once these hooks have been initialized, the node driver will call into
 222  * the hugetlb module to [un]register attributes for hot-plugged nodes.
 223  */
 224 static node_registration_func_t __hugetlb_register_node;
 225 static node_registration_func_t __hugetlb_unregister_node;
 226
 227 static inline bool hugetlb_register_node(struct node *node)
 228 {
 229         if (__hugetlb_register_node &&
 230                         node_state(node->dev.id, N_MEMORY)) {
 231                 __hugetlb_register_node(node);
 232                 return true;
 233         }
 234         return false;
 235 }
 236
 237 static inline void hugetlb_unregister_node(struct node *node)
 238 {
 239         if (__hugetlb_unregister_node)
 240                 __hugetlb_unregister_node(node);
 241 }
 242
 243 void register_hugetlbfs_with_node(node_registration_func_t doregister,
 244                                   node_registration_func_t unregister)
 245 {
 246         __hugetlb_register_node   = doregister;
 247         __hugetlb_unregister_node = unregister;
 248 }
 249 #else
 250 static inline void hugetlb_register_node(struct node *node) {}
 251
 252 static inline void hugetlb_unregister_node(struct node *node) {}
 253 #endif
 254
 255 static void node_device_release(struct device *dev)
 256 {
 257         struct node *node = to_node(dev);
 258
 259 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 260         /*
 261          * We schedule the work only when a memory section is
 262          * onlined/offlined on this node. When we come here,
 263          * all the memory on this node has been offlined,
 264          * so we won't enqueue new work to this work.
 265          *
 266          * The work is using node->node_work, so we should
 267          * flush work before freeing the memory.
 268          */
 269         flush_work(&node->node_work);
 270 #endif
 271         kfree(node);
 272 }
 273
 274 /*
 275  * register_node - Setup a sysfs device for a node.
 276  * @num - Node number to use when creating the device.
 277  *
 278  * Initialize and register the node device.
 279  */
 280 static int register_node(struct node *node, int num, struct node *parent)
 281 {
 282         int error;
 283
 284         node->dev.id = num;
 285         node->dev.bus = &node_subsys;
 286         node->dev.release = node_device_release;
 287         error = device_register(&node->dev);
 288
 289         if (!error){
 290                 device_create_file(&node->dev, &dev_attr_cpumap);
 291                 device_create_file(&node->dev, &dev_attr_cpulist);
 292                 device_create_file(&node->dev, &dev_attr_meminfo);
 293                 device_create_file(&node->dev, &dev_attr_numastat);
 294                 device_create_file(&node->dev, &dev_attr_distance);
 295                 device_create_file(&node->dev, &dev_attr_vmstat);
 296
 297                 scan_unevictable_register_node(node);
 298
 299                 hugetlb_register_node(node);
 300
 301                 compaction_register_node(node);
 302         }
 303         return error;
 304 }
 305
 306 /**
 307  * unregister_node - unregister a node device
 308  * @node: node going away
 309  *
 310  * Unregisters a node device @node.  All the devices on the node must be
 311  * unregistered before calling this function.
 312  */
 313 void unregister_node(struct node *node)
 314 {
 315         device_remove_file(&node->dev, &dev_attr_cpumap);
 316         device_remove_file(&node->dev, &dev_attr_cpulist);
 317         device_remove_file(&node->dev, &dev_attr_meminfo);
 318         device_remove_file(&node->dev, &dev_attr_numastat);
 319         device_remove_file(&node->dev, &dev_attr_distance);
 320         device_remove_file(&node->dev, &dev_attr_vmstat);
 321
 322         scan_unevictable_unregister_node(node);
 323         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 324
 325         device_unregister(&node->dev);
 326 }
 327
 328 struct node *node_devices[MAX_NUMNODES];
 329
 330 /*
 331  * register cpu under node
 332  */
 333 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 334 {
 335         int ret;
 336         struct device *obj;
 337
 338         if (!node_online(nid))
 339                 return 0;
 340
 341         obj = get_cpu_device(cpu);
 342         if (!obj)
 343                 return 0;
 344
 345         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 346                                 &obj->kobj,
 347                                 kobject_name(&obj->kobj));
 348         if (ret)
 349                 return ret;
 350
 351         return sysfs_create_link(&obj->kobj,
 352                                  &node_devices[nid]->dev.kobj,
 353                                  kobject_name(&node_devices[nid]->dev.kobj));
 354 }
 355
 356 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 357 {
 358         struct device *obj;
 359
 360         if (!node_online(nid))
 361                 return 0;
 362
 363         obj = get_cpu_device(cpu);
 364         if (!obj)
 365                 return 0;
 366
 367         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 368                           kobject_name(&obj->kobj));
 369         sysfs_remove_link(&obj->kobj,
 370                           kobject_name(&node_devices[nid]->dev.kobj));
 371
 372         return 0;
 373 }
 374
 375 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 376 #define page_initialized(page)  (page->lru.next)
 377
 378 static int get_nid_for_pfn(unsigned long pfn)
 379 {
 380         struct page *page;
 381
 382         if (!pfn_valid_within(pfn))
 383                 return -1;
 384         page = pfn_to_page(pfn);
 385         if (!page_initialized(page))
 386                 return -1;
 387         return pfn_to_nid(pfn);
 388 }
 389
 390 /* register memory section under specified node if it spans that node */
 391 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 392 {
 393         int ret;
 394         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 395
 396         if (!mem_blk)
 397                 return -EFAULT;
 398         if (!node_online(nid))
 399                 return 0;
 400
 401         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 402         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 403         sect_end_pfn += PAGES_PER_SECTION - 1;
 404         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 405                 int page_nid;
 406
 407                 page_nid = get_nid_for_pfn(pfn);
 408                 if (page_nid < 0)
 409                         continue;
 410                 if (page_nid != nid)
 411                         continue;
 412                 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 413                                         &mem_blk->dev.kobj,
 414                                         kobject_name(&mem_blk->dev.kobj));
 415                 if (ret)
 416                         return ret;
 417
 418                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 419                                 &node_devices[nid]->dev.kobj,
 420                                 kobject_name(&node_devices[nid]->dev.kobj));
 421         }
 422         /* mem section does not span the specified node */
 423         return 0;
 424 }
 425
 426 /* unregister memory section under all nodes that it spans */
 427 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 428                                     unsigned long phys_index)
 429 {
 430         NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 431         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 432
 433         if (!mem_blk) {
 434                 NODEMASK_FREE(unlinked_nodes);
 435                 return -EFAULT;
 436         }
 437         if (!unlinked_nodes)
 438                 return -ENOMEM;
 439         nodes_clear(*unlinked_nodes);
 440
 441         sect_start_pfn = section_nr_to_pfn(phys_index);
 442         sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 443         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 444                 int nid;
 445
 446                 nid = get_nid_for_pfn(pfn);
 447                 if (nid < 0)
 448                         continue;
 449                 if (!node_online(nid))
 450                         continue;
 451                 if (node_test_and_set(nid, *unlinked_nodes))
 452                         continue;
 453                 sysfs_remove_link(&node_devices[nid]->dev.kobj,
 454                          kobject_name(&mem_blk->dev.kobj));
 455                 sysfs_remove_link(&mem_blk->dev.kobj,
 456                          kobject_name(&node_devices[nid]->dev.kobj));
 457         }
 458         NODEMASK_FREE(unlinked_nodes);
 459         return 0;
 460 }
 461
 462 static int link_mem_sections(int nid)
 463 {
 464         unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
 465         unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
 466         unsigned long pfn;
 467         struct memory_block *mem_blk = NULL;
 468         int err = 0;
 469
 470         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 471                 unsigned long section_nr = pfn_to_section_nr(pfn);
 472                 struct mem_section *mem_sect;
 473                 int ret;
 474
 475                 if (!present_section_nr(section_nr))
 476                         continue;
 477                 mem_sect = __nr_to_section(section_nr);
 478
 479                 /* same memblock ? */
 480                 if (mem_blk)
 481                         if ((section_nr >= mem_blk->start_section_nr) &&
 482                             (section_nr <= mem_blk->end_section_nr))
 483                                 continue;
 484
 485                 mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
 486
 487                 ret = register_mem_sect_under_node(mem_blk, nid);
 488                 if (!err)
 489                         err = ret;
 490
 491                 /* discard ref obtained in find_memory_block() */
 492         }
 493
 494         if (mem_blk)
 495                 kobject_put(&mem_blk->dev.kobj);
 496         return err;
 497 }
 498
 499 #ifdef CONFIG_HUGETLBFS
 500 /*
 501  * Handle per node hstate attribute [un]registration on transistions
 502  * to/from memoryless state.
 503  */
 504 static void node_hugetlb_work(struct work_struct *work)
 505 {
 506         struct node *node = container_of(work, struct node, node_work);
 507
 508         /*
 509          * We only get here when a node transitions to/from memoryless state.
 510          * We can detect which transition occurred by examining whether the
 511          * node has memory now.  hugetlb_register_node() already check this
 512          * so we try to register the attributes.  If that fails, then the
 513          * node has transitioned to memoryless, try to unregister the
 514          * attributes.
 515          */
 516         if (!hugetlb_register_node(node))
 517                 hugetlb_unregister_node(node);
 518 }
 519
 520 static void init_node_hugetlb_work(int nid)
 521 {
 522         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 523 }
 524
 525 static int node_memory_callback(struct notifier_block *self,
 526                                 unsigned long action, void *arg)
 527 {
 528         struct memory_notify *mnb = arg;
 529         int nid = mnb->status_change_nid;
 530
 531         switch (action) {
 532         case MEM_ONLINE:
 533         case MEM_OFFLINE:
 534                 /*
 535                  * offload per node hstate [un]registration to a work thread
 536                  * when transitioning to/from memoryless state.
 537                  */
 538                 if (nid != NUMA_NO_NODE)
 539                         schedule_work(&node_devices[nid]->node_work);
 540                 break;
 541
 542         case MEM_GOING_ONLINE:
 543         case MEM_GOING_OFFLINE:
 544         case MEM_CANCEL_ONLINE:
 545         case MEM_CANCEL_OFFLINE:
 546         default:
 547                 break;
 548         }
 549
 550         return NOTIFY_OK;
 551 }
 552 #endif  /* CONFIG_HUGETLBFS */
 553 #else   /* !CONFIG_MEMORY_HOTPLUG_SPARSE */
 554
 555 static int link_mem_sections(int nid) { return 0; }
 556 #endif  /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 557
 558 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 559     !defined(CONFIG_HUGETLBFS)
 560 static inline int node_memory_callback(struct notifier_block *self,
 561                                 unsigned long action, void *arg)
 562 {
 563         return NOTIFY_OK;
 564 }
 565
 566 static void init_node_hugetlb_work(int nid) { }
 567
 568 #endif
 569
 570 int register_one_node(int nid)
 571 {
 572         int error = 0;
 573         int cpu;
 574
 575         if (node_online(nid)) {
 576                 int p_node = parent_node(nid);
 577                 struct node *parent = NULL;
 578
 579                 if (p_node != nid)
 580                         parent = node_devices[p_node];
 581
 582                 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 583                 if (!node_devices[nid])
 584                         return -ENOMEM;
 585
 586                 error = register_node(node_devices[nid], nid, parent);
 587
 588                 /* link cpu under this node */
 589                 for_each_present_cpu(cpu) {
 590                         if (cpu_to_node(cpu) == nid)
 591                                 register_cpu_under_node(cpu, nid);
 592                 }
 593
 594                 /* link memory sections under this node */
 595                 error = link_mem_sections(nid);
 596
 597                 /* initialize work queue for memory hot plug */
 598                 init_node_hugetlb_work(nid);
 599         }
 600
 601         return error;
 602
 603 }
 604
 605 void unregister_one_node(int nid)
 606 {
 607         unregister_node(node_devices[nid]);
 608         node_devices[nid] = NULL;
 609 }
 610
 611 /*
 612  * node states attributes
 613  */
 614
 615 static ssize_t print_nodes_state(enum node_states state, char *buf)
 616 {
 617         int n;
 618
 619         n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]);
 620         buf[n++] = '\n';
 621         buf[n] = '\0';
 622         return n;
 623 }
 624
 625 struct node_attr {
 626         struct device_attribute attr;
 627         enum node_states state;
 628 };
 629
 630 static ssize_t show_node_state(struct device *dev,
 631                                struct device_attribute *attr, char *buf)
 632 {
 633         struct node_attr *na = container_of(attr, struct node_attr, attr);
 634         return print_nodes_state(na->state, buf);
 635 }
 636
 637 #define _NODE_ATTR(name, state) \
 638         { __ATTR(name, 0444, show_node_state, NULL), state }
 639
 640 static struct node_attr node_state_attr[] = {
 641         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 642         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 643         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 644 #ifdef CONFIG_HIGHMEM
 645         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 646 #endif
 647 #ifdef CONFIG_MOVABLE_NODE
 648         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 649 #endif
 650         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 651 };
 652
 653 static struct attribute *node_state_attrs[] = {
 654         &node_state_attr[N_POSSIBLE].attr.attr,
 655         &node_state_attr[N_ONLINE].attr.attr,
 656         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 657 #ifdef CONFIG_HIGHMEM
 658         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 659 #endif
 660 #ifdef CONFIG_MOVABLE_NODE
 661         &node_state_attr[N_MEMORY].attr.attr,
 662 #endif
 663         &node_state_attr[N_CPU].attr.attr,
 664         NULL
 665 };
 666
 667 static struct attribute_group memory_root_attr_group = {
 668         .attrs = node_state_attrs,
 669 };
 670
 671 static const struct attribute_group *cpu_root_attr_groups[] = {
 672         &memory_root_attr_group,
 673         NULL,
 674 };
 675
 676 #define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 677 static int __init register_node_type(void)
 678 {
 679         int ret;
 680
 681         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 682         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 683
 684         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 685         if (!ret) {
 686                 hotplug_memory_notifier(node_memory_callback,
 687                                         NODE_CALLBACK_PRI);
 688         }
 689
 690         /*
 691          * Note:  we're not going to unregister the node class if we fail
 692          * to register the node state class attribute files.
 693          */
 694         return ret;
 695 }
 696 postcore_initcall(register_node_type);