drivers/base/node.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Basic Node interface support
   4  */
   5
   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/notifier.h>
  12 #include <linux/node.h>
  13 #include <linux/hugetlb.h>
  14 #include <linux/compaction.h>
  15 #include <linux/cpumask.h>
  16 #include <linux/topology.h>
  17 #include <linux/nodemask.h>
  18 #include <linux/cpu.h>
  19 #include <linux/device.h>
  20 #include <linux/swap.h>
  21 #include <linux/slab.h>
  22
  23 static struct bus_type node_subsys = {
  24         .name = "node",
  25         .dev_name = "node",
  26 };
  27
  28
  29 static ssize_t node_read_cpumap(struct device *dev, bool list, char *buf)
  30 {
  31         ssize_t n;
  32         cpumask_var_t mask;
  33         struct node *node_dev = to_node(dev);
  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         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  39                 return 0;
  40
  41         cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
  42         n = cpumap_print_to_pagebuf(list, buf, mask);
  43         free_cpumask_var(mask);
  44
  45         return n;
  46 }
  47
  48 static inline ssize_t node_read_cpumask(struct device *dev,
  49                                 struct device_attribute *attr, char *buf)
  50 {
  51         return node_read_cpumap(dev, false, buf);
  52 }
  53 static inline ssize_t node_read_cpulist(struct device *dev,
  54                                 struct device_attribute *attr, char *buf)
  55 {
  56         return node_read_cpumap(dev, true, buf);
  57 }
  58
  59 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
  60 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
  61
  62 #define K(x) ((x) << (PAGE_SHIFT - 10))
  63 static ssize_t node_read_meminfo(struct device *dev,
  64                         struct device_attribute *attr, char *buf)
  65 {
  66         int n;
  67         int nid = dev->id;
  68         struct pglist_data *pgdat = NODE_DATA(nid);
  69         struct sysinfo i;
  70
  71         si_meminfo_node(&i, nid);
  72         n = sprintf(buf,
  73                        "Node %d MemTotal:       %8lu kB\n"
  74                        "Node %d MemFree:        %8lu kB\n"
  75                        "Node %d MemUsed:        %8lu kB\n"
  76                        "Node %d Active:         %8lu kB\n"
  77                        "Node %d Inactive:       %8lu kB\n"
  78                        "Node %d Active(anon):   %8lu kB\n"
  79                        "Node %d Inactive(anon): %8lu kB\n"
  80                        "Node %d Active(file):   %8lu kB\n"
  81                        "Node %d Inactive(file): %8lu kB\n"
  82                        "Node %d Unevictable:    %8lu kB\n"
  83                        "Node %d Mlocked:        %8lu kB\n",
  84                        nid, K(i.totalram),
  85                        nid, K(i.freeram),
  86                        nid, K(i.totalram - i.freeram),
  87                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
  88                                 node_page_state(pgdat, NR_ACTIVE_FILE)),
  89                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
  90                                 node_page_state(pgdat, NR_INACTIVE_FILE)),
  91                        nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
  92                        nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
  93                        nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
  94                        nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
  95                        nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
  96                        nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
  97
  98 #ifdef CONFIG_HIGHMEM
  99         n += sprintf(buf + n,
 100                        "Node %d HighTotal:      %8lu kB\n"
 101                        "Node %d HighFree:       %8lu kB\n"
 102                        "Node %d LowTotal:       %8lu kB\n"
 103                        "Node %d LowFree:        %8lu kB\n",
 104                        nid, K(i.totalhigh),
 105                        nid, K(i.freehigh),
 106                        nid, K(i.totalram - i.totalhigh),
 107                        nid, K(i.freeram - i.freehigh));
 108 #endif
 109         n += sprintf(buf + n,
 110                        "Node %d Dirty:          %8lu kB\n"
 111                        "Node %d Writeback:      %8lu kB\n"
 112                        "Node %d FilePages:      %8lu kB\n"
 113                        "Node %d Mapped:         %8lu kB\n"
 114                        "Node %d AnonPages:      %8lu kB\n"
 115                        "Node %d Shmem:          %8lu kB\n"
 116                        "Node %d KernelStack:    %8lu kB\n"
 117                        "Node %d PageTables:     %8lu kB\n"
 118                        "Node %d NFS_Unstable:   %8lu kB\n"
 119                        "Node %d Bounce:         %8lu kB\n"
 120                        "Node %d WritebackTmp:   %8lu kB\n"
 121                        "Node %d Slab:           %8lu kB\n"
 122                        "Node %d SReclaimable:   %8lu kB\n"
 123                        "Node %d SUnreclaim:     %8lu kB\n"
 124 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 125                        "Node %d AnonHugePages:  %8lu kB\n"
 126                        "Node %d ShmemHugePages: %8lu kB\n"
 127                        "Node %d ShmemPmdMapped: %8lu kB\n"
 128 #endif
 129                         ,
 130                        nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
 131                        nid, K(node_page_state(pgdat, NR_WRITEBACK)),
 132                        nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
 133                        nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
 134                        nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
 135                        nid, K(i.sharedram),
 136                        nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK_KB),
 137                        nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),
 138                        nid, K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
 139                        nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
 140                        nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
 141                        nid, K(node_page_state(pgdat, NR_SLAB_RECLAIMABLE) +
 142                               node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)),
 143                        nid, K(node_page_state(pgdat, NR_SLAB_RECLAIMABLE)),
 144 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 145                        nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)),
 146                        nid, K(node_page_state(pgdat, NR_ANON_THPS) *
 147                                        HPAGE_PMD_NR),
 148                        nid, K(node_page_state(pgdat, NR_SHMEM_THPS) *
 149                                        HPAGE_PMD_NR),
 150                        nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) *
 151                                        HPAGE_PMD_NR));
 152 #else
 153                        nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)));
 154 #endif
 155         n += hugetlb_report_node_meminfo(nid, buf + n);
 156         return n;
 157 }
 158
 159 #undef K
 160 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 161
 162 static ssize_t node_read_numastat(struct device *dev,
 163                                 struct device_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                        sum_zone_numa_state(dev->id, NUMA_HIT),
 173                        sum_zone_numa_state(dev->id, NUMA_MISS),
 174                        sum_zone_numa_state(dev->id, NUMA_FOREIGN),
 175                        sum_zone_numa_state(dev->id, NUMA_INTERLEAVE_HIT),
 176                        sum_zone_numa_state(dev->id, NUMA_LOCAL),
 177                        sum_zone_numa_state(dev->id, NUMA_OTHER));
 178 }
 179 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 180
 181 static ssize_t node_read_vmstat(struct device *dev,
 182                                 struct device_attribute *attr, char *buf)
 183 {
 184         int nid = dev->id;
 185         struct pglist_data *pgdat = NODE_DATA(nid);
 186         int i;
 187         int n = 0;
 188
 189         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 190                 n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
 191                              sum_zone_node_page_state(nid, i));
 192
 193 #ifdef CONFIG_NUMA
 194         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 195                 n += sprintf(buf+n, "%s %lu\n",
 196                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
 197                              sum_zone_numa_state(nid, i));
 198 #endif
 199
 200         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
 201                 /* Skip hidden vmstat items. */
 202                 if (*vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
 203                                  NR_VM_NUMA_STAT_ITEMS] == '\0')
 204                         continue;
 205                 n += sprintf(buf+n, "%s %lu\n",
 206                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
 207                              NR_VM_NUMA_STAT_ITEMS],
 208                              node_page_state(pgdat, i));
 209         }
 210
 211         return n;
 212 }
 213 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 214
 215 static ssize_t node_read_distance(struct device *dev,
 216                         struct device_attribute *attr, char *buf)
 217 {
 218         int nid = dev->id;
 219         int len = 0;
 220         int i;
 221
 222         /*
 223          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 224          * at the most (distance + space or newline).
 225          */
 226         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 227
 228         for_each_online_node(i)
 229                 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 230
 231         len += sprintf(buf + len, "\n");
 232         return len;
 233 }
 234 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 235
 236 static struct attribute *node_dev_attrs[] = {
 237         &dev_attr_cpumap.attr,
 238         &dev_attr_cpulist.attr,
 239         &dev_attr_meminfo.attr,
 240         &dev_attr_numastat.attr,
 241         &dev_attr_distance.attr,
 242         &dev_attr_vmstat.attr,
 243         NULL
 244 };
 245 ATTRIBUTE_GROUPS(node_dev);
 246
 247 #ifdef CONFIG_HUGETLBFS
 248 /*
 249  * hugetlbfs per node attributes registration interface:
 250  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 251  * it will register its per node attributes for all online nodes with
 252  * memory.  It will also call register_hugetlbfs_with_node(), below, to
 253  * register its attribute registration functions with this node driver.
 254  * Once these hooks have been initialized, the node driver will call into
 255  * the hugetlb module to [un]register attributes for hot-plugged nodes.
 256  */
 257 static node_registration_func_t __hugetlb_register_node;
 258 static node_registration_func_t __hugetlb_unregister_node;
 259
 260 static inline bool hugetlb_register_node(struct node *node)
 261 {
 262         if (__hugetlb_register_node &&
 263                         node_state(node->dev.id, N_MEMORY)) {
 264                 __hugetlb_register_node(node);
 265                 return true;
 266         }
 267         return false;
 268 }
 269
 270 static inline void hugetlb_unregister_node(struct node *node)
 271 {
 272         if (__hugetlb_unregister_node)
 273                 __hugetlb_unregister_node(node);
 274 }
 275
 276 void register_hugetlbfs_with_node(node_registration_func_t doregister,
 277                                   node_registration_func_t unregister)
 278 {
 279         __hugetlb_register_node   = doregister;
 280         __hugetlb_unregister_node = unregister;
 281 }
 282 #else
 283 static inline void hugetlb_register_node(struct node *node) {}
 284
 285 static inline void hugetlb_unregister_node(struct node *node) {}
 286 #endif
 287
 288 static void node_device_release(struct device *dev)
 289 {
 290         struct node *node = to_node(dev);
 291
 292 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 293         /*
 294          * We schedule the work only when a memory section is
 295          * onlined/offlined on this node. When we come here,
 296          * all the memory on this node has been offlined,
 297          * so we won't enqueue new work to this work.
 298          *
 299          * The work is using node->node_work, so we should
 300          * flush work before freeing the memory.
 301          */
 302         flush_work(&node->node_work);
 303 #endif
 304         kfree(node);
 305 }
 306
 307 /*
 308  * register_node - Setup a sysfs device for a node.
 309  * @num - Node number to use when creating the device.
 310  *
 311  * Initialize and register the node device.
 312  */
 313 static int register_node(struct node *node, int num)
 314 {
 315         int error;
 316
 317         node->dev.id = num;
 318         node->dev.bus = &node_subsys;
 319         node->dev.release = node_device_release;
 320         node->dev.groups = node_dev_groups;
 321         error = device_register(&node->dev);
 322
 323         if (!error){
 324                 hugetlb_register_node(node);
 325
 326                 compaction_register_node(node);
 327         }
 328         return error;
 329 }
 330
 331 /**
 332  * unregister_node - unregister a node device
 333  * @node: node going away
 334  *
 335  * Unregisters a node device @node.  All the devices on the node must be
 336  * unregistered before calling this function.
 337  */
 338 void unregister_node(struct node *node)
 339 {
 340         compaction_unregister_node(node);
 341         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 342
 343         device_unregister(&node->dev);
 344 }
 345
 346 struct node *node_devices[MAX_NUMNODES];
 347
 348 /*
 349  * register cpu under node
 350  */
 351 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 352 {
 353         int ret;
 354         struct device *obj;
 355
 356         if (!node_online(nid))
 357                 return 0;
 358
 359         obj = get_cpu_device(cpu);
 360         if (!obj)
 361                 return 0;
 362
 363         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 364                                 &obj->kobj,
 365                                 kobject_name(&obj->kobj));
 366         if (ret)
 367                 return ret;
 368
 369         return sysfs_create_link(&obj->kobj,
 370                                  &node_devices[nid]->dev.kobj,
 371                                  kobject_name(&node_devices[nid]->dev.kobj));
 372 }
 373
 374 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 375 {
 376         struct device *obj;
 377
 378         if (!node_online(nid))
 379                 return 0;
 380
 381         obj = get_cpu_device(cpu);
 382         if (!obj)
 383                 return 0;
 384
 385         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 386                           kobject_name(&obj->kobj));
 387         sysfs_remove_link(&obj->kobj,
 388                           kobject_name(&node_devices[nid]->dev.kobj));
 389
 390         return 0;
 391 }
 392
 393 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 394 static int __ref get_nid_for_pfn(unsigned long pfn)
 395 {
 396         if (!pfn_valid_within(pfn))
 397                 return -1;
 398 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 399         if (system_state < SYSTEM_RUNNING)
 400                 return early_pfn_to_nid(pfn);
 401 #endif
 402         return pfn_to_nid(pfn);
 403 }
 404
 405 /* register memory section under specified node if it spans that node */
 406 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 407 {
 408         int ret;
 409         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 410
 411         if (!mem_blk)
 412                 return -EFAULT;
 413         if (!node_online(nid))
 414                 return 0;
 415
 416         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 417         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 418         sect_end_pfn += PAGES_PER_SECTION - 1;
 419         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 420                 int page_nid;
 421
 422                 /*
 423                  * memory block could have several absent sections from start.
 424                  * skip pfn range from absent section
 425                  */
 426                 if (!pfn_present(pfn)) {
 427                         pfn = round_down(pfn + PAGES_PER_SECTION,
 428                                          PAGES_PER_SECTION) - 1;
 429                         continue;
 430                 }
 431
 432                 page_nid = get_nid_for_pfn(pfn);
 433                 if (page_nid < 0)
 434                         continue;
 435                 if (page_nid != nid)
 436                         continue;
 437                 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 438                                         &mem_blk->dev.kobj,
 439                                         kobject_name(&mem_blk->dev.kobj));
 440                 if (ret)
 441                         return ret;
 442
 443                 return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 444                                 &node_devices[nid]->dev.kobj,
 445                                 kobject_name(&node_devices[nid]->dev.kobj));
 446         }
 447         /* mem section does not span the specified node */
 448         return 0;
 449 }
 450
 451 /* unregister memory section under all nodes that it spans */
 452 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 453                                     unsigned long phys_index)
 454 {
 455         NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 456         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 457
 458         if (!mem_blk) {
 459                 NODEMASK_FREE(unlinked_nodes);
 460                 return -EFAULT;
 461         }
 462         if (!unlinked_nodes)
 463                 return -ENOMEM;
 464         nodes_clear(*unlinked_nodes);
 465
 466         sect_start_pfn = section_nr_to_pfn(phys_index);
 467         sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 468         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 469                 int nid;
 470
 471                 nid = get_nid_for_pfn(pfn);
 472                 if (nid < 0)
 473                         continue;
 474                 if (!node_online(nid))
 475                         continue;
 476                 if (node_test_and_set(nid, *unlinked_nodes))
 477                         continue;
 478                 sysfs_remove_link(&node_devices[nid]->dev.kobj,
 479                          kobject_name(&mem_blk->dev.kobj));
 480                 sysfs_remove_link(&mem_blk->dev.kobj,
 481                          kobject_name(&node_devices[nid]->dev.kobj));
 482         }
 483         NODEMASK_FREE(unlinked_nodes);
 484         return 0;
 485 }
 486
 487 int link_mem_sections(int nid, unsigned long start_pfn, unsigned long nr_pages)
 488 {
 489         unsigned long end_pfn = start_pfn + nr_pages;
 490         unsigned long pfn;
 491         struct memory_block *mem_blk = NULL;
 492         int err = 0;
 493
 494         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 495                 unsigned long section_nr = pfn_to_section_nr(pfn);
 496                 struct mem_section *mem_sect;
 497                 int ret;
 498
 499                 if (!present_section_nr(section_nr))
 500                         continue;
 501                 mem_sect = __nr_to_section(section_nr);
 502
 503                 /* same memblock ? */
 504                 if (mem_blk)
 505                         if ((section_nr >= mem_blk->start_section_nr) &&
 506                             (section_nr <= mem_blk->end_section_nr))
 507                                 continue;
 508
 509                 mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
 510
 511                 ret = register_mem_sect_under_node(mem_blk, nid);
 512                 if (!err)
 513                         err = ret;
 514
 515                 /* discard ref obtained in find_memory_block() */
 516         }
 517
 518         if (mem_blk)
 519                 kobject_put(&mem_blk->dev.kobj);
 520         return err;
 521 }
 522
 523 #ifdef CONFIG_HUGETLBFS
 524 /*
 525  * Handle per node hstate attribute [un]registration on transistions
 526  * to/from memoryless state.
 527  */
 528 static void node_hugetlb_work(struct work_struct *work)
 529 {
 530         struct node *node = container_of(work, struct node, node_work);
 531
 532         /*
 533          * We only get here when a node transitions to/from memoryless state.
 534          * We can detect which transition occurred by examining whether the
 535          * node has memory now.  hugetlb_register_node() already check this
 536          * so we try to register the attributes.  If that fails, then the
 537          * node has transitioned to memoryless, try to unregister the
 538          * attributes.
 539          */
 540         if (!hugetlb_register_node(node))
 541                 hugetlb_unregister_node(node);
 542 }
 543
 544 static void init_node_hugetlb_work(int nid)
 545 {
 546         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 547 }
 548
 549 static int node_memory_callback(struct notifier_block *self,
 550                                 unsigned long action, void *arg)
 551 {
 552         struct memory_notify *mnb = arg;
 553         int nid = mnb->status_change_nid;
 554
 555         switch (action) {
 556         case MEM_ONLINE:
 557         case MEM_OFFLINE:
 558                 /*
 559                  * offload per node hstate [un]registration to a work thread
 560                  * when transitioning to/from memoryless state.
 561                  */
 562                 if (nid != NUMA_NO_NODE)
 563                         schedule_work(&node_devices[nid]->node_work);
 564                 break;
 565
 566         case MEM_GOING_ONLINE:
 567         case MEM_GOING_OFFLINE:
 568         case MEM_CANCEL_ONLINE:
 569         case MEM_CANCEL_OFFLINE:
 570         default:
 571                 break;
 572         }
 573
 574         return NOTIFY_OK;
 575 }
 576 #endif  /* CONFIG_HUGETLBFS */
 577 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 578
 579 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 580     !defined(CONFIG_HUGETLBFS)
 581 static inline int node_memory_callback(struct notifier_block *self,
 582                                 unsigned long action, void *arg)
 583 {
 584         return NOTIFY_OK;
 585 }
 586
 587 static void init_node_hugetlb_work(int nid) { }
 588
 589 #endif
 590
 591 int __register_one_node(int nid)
 592 {
 593         int error;
 594         int cpu;
 595
 596         node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 597         if (!node_devices[nid])
 598                 return -ENOMEM;
 599
 600         error = register_node(node_devices[nid], nid);
 601
 602         /* link cpu under this node */
 603         for_each_present_cpu(cpu) {
 604                 if (cpu_to_node(cpu) == nid)
 605                         register_cpu_under_node(cpu, nid);
 606         }
 607
 608         /* initialize work queue for memory hot plug */
 609         init_node_hugetlb_work(nid);
 610
 611         return error;
 612 }
 613
 614 void unregister_one_node(int nid)
 615 {
 616         if (!node_devices[nid])
 617                 return;
 618
 619         unregister_node(node_devices[nid]);
 620         node_devices[nid] = NULL;
 621 }
 622
 623 /*
 624  * node states attributes
 625  */
 626
 627 static ssize_t print_nodes_state(enum node_states state, char *buf)
 628 {
 629         int n;
 630
 631         n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
 632                       nodemask_pr_args(&node_states[state]));
 633         buf[n++] = '\n';
 634         buf[n] = '\0';
 635         return n;
 636 }
 637
 638 struct node_attr {
 639         struct device_attribute attr;
 640         enum node_states state;
 641 };
 642
 643 static ssize_t show_node_state(struct device *dev,
 644                                struct device_attribute *attr, char *buf)
 645 {
 646         struct node_attr *na = container_of(attr, struct node_attr, attr);
 647         return print_nodes_state(na->state, buf);
 648 }
 649
 650 #define _NODE_ATTR(name, state) \
 651         { __ATTR(name, 0444, show_node_state, NULL), state }
 652
 653 static struct node_attr node_state_attr[] = {
 654         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 655         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 656         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 657 #ifdef CONFIG_HIGHMEM
 658         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 659 #endif
 660         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 661         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 662 };
 663
 664 static struct attribute *node_state_attrs[] = {
 665         &node_state_attr[N_POSSIBLE].attr.attr,
 666         &node_state_attr[N_ONLINE].attr.attr,
 667         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 668 #ifdef CONFIG_HIGHMEM
 669         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 670 #endif
 671         &node_state_attr[N_MEMORY].attr.attr,
 672         &node_state_attr[N_CPU].attr.attr,
 673         NULL
 674 };
 675
 676 static struct attribute_group memory_root_attr_group = {
 677         .attrs = node_state_attrs,
 678 };
 679
 680 static const struct attribute_group *cpu_root_attr_groups[] = {
 681         &memory_root_attr_group,
 682         NULL,
 683 };
 684
 685 #define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 686 static int __init register_node_type(void)
 687 {
 688         int ret;
 689
 690         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 691         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 692
 693         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 694         if (!ret) {
 695                 static struct notifier_block node_memory_callback_nb = {
 696                         .notifier_call = node_memory_callback,
 697                         .priority = NODE_CALLBACK_PRI,
 698                 };
 699                 register_hotmemory_notifier(&node_memory_callback_nb);
 700         }
 701
 702         /*
 703          * Note:  we're not going to unregister the node class if we fail
 704          * to register the node state class attribute files.
 705          */
 706         return ret;
 707 }
 708 postcore_initcall(register_node_type);