drivers/base/node.c

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