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                 n += sprintf(buf+n, "%s %lu\n",
 202                              vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
 203                              NR_VM_NUMA_STAT_ITEMS],
 204                              node_page_state(pgdat, i));
 205
 206         return n;
 207 }
 208 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 209
 210 static ssize_t node_read_distance(struct device *dev,
 211                         struct device_attribute *attr, char *buf)
 212 {
 213         int nid = dev->id;
 214         int len = 0;
 215         int i;
 216
 217         /*
 218          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 219          * at the most (distance + space or newline).
 220          */
 221         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 222
 223         for_each_online_node(i)
 224                 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 225
 226         len += sprintf(buf + len, "\n");
 227         return len;
 228 }
 229 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 230
 231 static struct attribute *node_dev_attrs[] = {
 232         &dev_attr_cpumap.attr,
 233         &dev_attr_cpulist.attr,
 234         &dev_attr_meminfo.attr,
 235         &dev_attr_numastat.attr,
 236         &dev_attr_distance.attr,
 237         &dev_attr_vmstat.attr,
 238         NULL
 239 };
 240 ATTRIBUTE_GROUPS(node_dev);
 241
 242 #ifdef CONFIG_HUGETLBFS
 243 /*
 244  * hugetlbfs per node attributes registration interface:
 245  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 246  * it will register its per node attributes for all online nodes with
 247  * memory.  It will also call register_hugetlbfs_with_node(), below, to
 248  * register its attribute registration functions with this node driver.
 249  * Once these hooks have been initialized, the node driver will call into
 250  * the hugetlb module to [un]register attributes for hot-plugged nodes.
 251  */
 252 static node_registration_func_t __hugetlb_register_node;
 253 static node_registration_func_t __hugetlb_unregister_node;
 254
 255 static inline bool hugetlb_register_node(struct node *node)
 256 {
 257         if (__hugetlb_register_node &&
 258                         node_state(node->dev.id, N_MEMORY)) {
 259                 __hugetlb_register_node(node);
 260                 return true;
 261         }
 262         return false;
 263 }
 264
 265 static inline void hugetlb_unregister_node(struct node *node)
 266 {
 267         if (__hugetlb_unregister_node)
 268                 __hugetlb_unregister_node(node);
 269 }
 270
 271 void register_hugetlbfs_with_node(node_registration_func_t doregister,
 272                                   node_registration_func_t unregister)
 273 {
 274         __hugetlb_register_node   = doregister;
 275         __hugetlb_unregister_node = unregister;
 276 }
 277 #else
 278 static inline void hugetlb_register_node(struct node *node) {}
 279
 280 static inline void hugetlb_unregister_node(struct node *node) {}
 281 #endif
 282
 283 static void node_device_release(struct device *dev)
 284 {
 285         struct node *node = to_node(dev);
 286
 287 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 288         /*
 289          * We schedule the work only when a memory section is
 290          * onlined/offlined on this node. When we come here,
 291          * all the memory on this node has been offlined,
 292          * so we won't enqueue new work to this work.
 293          *
 294          * The work is using node->node_work, so we should
 295          * flush work before freeing the memory.
 296          */
 297         flush_work(&node->node_work);
 298 #endif
 299         kfree(node);
 300 }
 301
 302 /*
 303  * register_node - Setup a sysfs device for a node.
 304  * @num - Node number to use when creating the device.
 305  *
 306  * Initialize and register the node device.
 307  */
 308 static int register_node(struct node *node, int num)
 309 {
 310         int error;
 311
 312         node->dev.id = num;
 313         node->dev.bus = &node_subsys;
 314         node->dev.release = node_device_release;
 315         node->dev.groups = node_dev_groups;
 316         error = device_register(&node->dev);
 317
 318         if (error)
 319                 put_device(&node->dev);
 320         else {
 321                 hugetlb_register_node(node);
 322
 323                 compaction_register_node(node);
 324         }
 325         return error;
 326 }
 327
 328 /**
 329  * unregister_node - unregister a node device
 330  * @node: node going away
 331  *
 332  * Unregisters a node device @node.  All the devices on the node must be
 333  * unregistered before calling this function.
 334  */
 335 void unregister_node(struct node *node)
 336 {
 337         hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 338
 339         device_unregister(&node->dev);
 340 }
 341
 342 struct node *node_devices[MAX_NUMNODES];
 343
 344 /*
 345  * register cpu under node
 346  */
 347 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 348 {
 349         int ret;
 350         struct device *obj;
 351
 352         if (!node_online(nid))
 353                 return 0;
 354
 355         obj = get_cpu_device(cpu);
 356         if (!obj)
 357                 return 0;
 358
 359         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 360                                 &obj->kobj,
 361                                 kobject_name(&obj->kobj));
 362         if (ret)
 363                 return ret;
 364
 365         return sysfs_create_link(&obj->kobj,
 366                                  &node_devices[nid]->dev.kobj,
 367                                  kobject_name(&node_devices[nid]->dev.kobj));
 368 }
 369
 370 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 371 {
 372         struct device *obj;
 373
 374         if (!node_online(nid))
 375                 return 0;
 376
 377         obj = get_cpu_device(cpu);
 378         if (!obj)
 379                 return 0;
 380
 381         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 382                           kobject_name(&obj->kobj));
 383         sysfs_remove_link(&obj->kobj,
 384                           kobject_name(&node_devices[nid]->dev.kobj));
 385
 386         return 0;
 387 }
 388
 389 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 390 static int __ref get_nid_for_pfn(unsigned long pfn)
 391 {
 392         if (!pfn_valid_within(pfn))
 393                 return -1;
 394 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 395         if (system_state < SYSTEM_RUNNING)
 396                 return early_pfn_to_nid(pfn);
 397 #endif
 398         return pfn_to_nid(pfn);
 399 }
 400
 401 /* register memory section under specified node if it spans that node */
 402 int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg)
 403 {
 404         int ret, nid = *(int *)arg;
 405         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 406
 407         mem_blk->nid = nid;
 408
 409         sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 410         sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 411         sect_end_pfn += PAGES_PER_SECTION - 1;
 412         for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 413                 int page_nid;
 414
 415                 /*
 416                  * memory block could have several absent sections from start.
 417                  * skip pfn range from absent section
 418                  */
 419                 if (!pfn_present(pfn)) {
 420                         pfn = round_down(pfn + PAGES_PER_SECTION,
 421                                          PAGES_PER_SECTION) - 1;
 422                         continue;
 423                 }
 424
 425                 /*
 426                  * We need to check if page belongs to nid only for the boot
 427                  * case, during hotplug we know that all pages in the memory
 428                  * block belong to the same node.
 429                  */
 430                 if (system_state == SYSTEM_BOOTING) {
 431                         page_nid = get_nid_for_pfn(pfn);
 432                         if (page_nid < 0)
 433                                 continue;
 434                         if (page_nid != nid)
 435                                 continue;
 436                 }
 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 end_pfn)
 488 {
 489         return walk_memory_range(start_pfn, end_pfn, (void *)&nid,
 490                                         register_mem_sect_under_node);
 491 }
 492
 493 #ifdef CONFIG_HUGETLBFS
 494 /*
 495  * Handle per node hstate attribute [un]registration on transistions
 496  * to/from memoryless state.
 497  */
 498 static void node_hugetlb_work(struct work_struct *work)
 499 {
 500         struct node *node = container_of(work, struct node, node_work);
 501
 502         /*
 503          * We only get here when a node transitions to/from memoryless state.
 504          * We can detect which transition occurred by examining whether the
 505          * node has memory now.  hugetlb_register_node() already check this
 506          * so we try to register the attributes.  If that fails, then the
 507          * node has transitioned to memoryless, try to unregister the
 508          * attributes.
 509          */
 510         if (!hugetlb_register_node(node))
 511                 hugetlb_unregister_node(node);
 512 }
 513
 514 static void init_node_hugetlb_work(int nid)
 515 {
 516         INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 517 }
 518
 519 static int node_memory_callback(struct notifier_block *self,
 520                                 unsigned long action, void *arg)
 521 {
 522         struct memory_notify *mnb = arg;
 523         int nid = mnb->status_change_nid;
 524
 525         switch (action) {
 526         case MEM_ONLINE:
 527         case MEM_OFFLINE:
 528                 /*
 529                  * offload per node hstate [un]registration to a work thread
 530                  * when transitioning to/from memoryless state.
 531                  */
 532                 if (nid != NUMA_NO_NODE)
 533                         schedule_work(&node_devices[nid]->node_work);
 534                 break;
 535
 536         case MEM_GOING_ONLINE:
 537         case MEM_GOING_OFFLINE:
 538         case MEM_CANCEL_ONLINE:
 539         case MEM_CANCEL_OFFLINE:
 540         default:
 541                 break;
 542         }
 543
 544         return NOTIFY_OK;
 545 }
 546 #endif  /* CONFIG_HUGETLBFS */
 547 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 548
 549 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 550     !defined(CONFIG_HUGETLBFS)
 551 static inline int node_memory_callback(struct notifier_block *self,
 552                                 unsigned long action, void *arg)
 553 {
 554         return NOTIFY_OK;
 555 }
 556
 557 static void init_node_hugetlb_work(int nid) { }
 558
 559 #endif
 560
 561 int __register_one_node(int nid)
 562 {
 563         int error;
 564         int cpu;
 565
 566         node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 567         if (!node_devices[nid])
 568                 return -ENOMEM;
 569
 570         error = register_node(node_devices[nid], nid);
 571
 572         /* link cpu under this node */
 573         for_each_present_cpu(cpu) {
 574                 if (cpu_to_node(cpu) == nid)
 575                         register_cpu_under_node(cpu, nid);
 576         }
 577
 578         /* initialize work queue for memory hot plug */
 579         init_node_hugetlb_work(nid);
 580
 581         return error;
 582 }
 583
 584 void unregister_one_node(int nid)
 585 {
 586         if (!node_devices[nid])
 587                 return;
 588
 589         unregister_node(node_devices[nid]);
 590         node_devices[nid] = NULL;
 591 }
 592
 593 /*
 594  * node states attributes
 595  */
 596
 597 static ssize_t print_nodes_state(enum node_states state, char *buf)
 598 {
 599         int n;
 600
 601         n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
 602                       nodemask_pr_args(&node_states[state]));
 603         buf[n++] = '\n';
 604         buf[n] = '\0';
 605         return n;
 606 }
 607
 608 struct node_attr {
 609         struct device_attribute attr;
 610         enum node_states state;
 611 };
 612
 613 static ssize_t show_node_state(struct device *dev,
 614                                struct device_attribute *attr, char *buf)
 615 {
 616         struct node_attr *na = container_of(attr, struct node_attr, attr);
 617         return print_nodes_state(na->state, buf);
 618 }
 619
 620 #define _NODE_ATTR(name, state) \
 621         { __ATTR(name, 0444, show_node_state, NULL), state }
 622
 623 static struct node_attr node_state_attr[] = {
 624         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 625         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 626         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 627 #ifdef CONFIG_HIGHMEM
 628         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 629 #endif
 630         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 631         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 632 };
 633
 634 static struct attribute *node_state_attrs[] = {
 635         &node_state_attr[N_POSSIBLE].attr.attr,
 636         &node_state_attr[N_ONLINE].attr.attr,
 637         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 638 #ifdef CONFIG_HIGHMEM
 639         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 640 #endif
 641         &node_state_attr[N_MEMORY].attr.attr,
 642         &node_state_attr[N_CPU].attr.attr,
 643         NULL
 644 };
 645
 646 static struct attribute_group memory_root_attr_group = {
 647         .attrs = node_state_attrs,
 648 };
 649
 650 static const struct attribute_group *cpu_root_attr_groups[] = {
 651         &memory_root_attr_group,
 652         NULL,
 653 };
 654
 655 #define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 656 static int __init register_node_type(void)
 657 {
 658         int ret;
 659
 660         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 661         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 662
 663         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 664         if (!ret) {
 665                 static struct notifier_block node_memory_callback_nb = {
 666                         .notifier_call = node_memory_callback,
 667                         .priority = NODE_CALLBACK_PRI,
 668                 };
 669                 register_hotmemory_notifier(&node_memory_callback_nb);
 670         }
 671
 672         /*
 673          * Note:  we're not going to unregister the node class if we fail
 674          * to register the node state class attribute files.
 675          */
 676         return ret;
 677 }
 678 postcore_initcall(register_node_type);