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