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