linux/drivers/base/node.c
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   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
  22static struct bus_type node_subsys = {
  23        .name = "node",
  24        .dev_name = "node",
  25};
  26
  27
  28static ssize_t node_read_cpumap(struct device *dev, int type, char *buf)
  29{
  30        struct node *node_dev = to_node(dev);
  31        const struct cpumask *mask = cpumask_of_node(node_dev->dev.id);
  32        int len;
  33
  34        /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
  35        BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
  36
  37        len = type?
  38                cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
  39                cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
  40        buf[len++] = '\n';
  41        buf[len] = '\0';
  42        return len;
  43}
  44
  45static inline ssize_t node_read_cpumask(struct device *dev,
  46                                struct device_attribute *attr, char *buf)
  47{
  48        return node_read_cpumap(dev, 0, buf);
  49}
  50static inline ssize_t node_read_cpulist(struct device *dev,
  51                                struct device_attribute *attr, char *buf)
  52{
  53        return node_read_cpumap(dev, 1, buf);
  54}
  55
  56static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
  57static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
  58
  59#define K(x) ((x) << (PAGE_SHIFT - 10))
  60static ssize_t node_read_meminfo(struct device *dev,
  61                        struct device_attribute *attr, char *buf)
  62{
  63        int n;
  64        int nid = dev->id;
  65        struct sysinfo i;
  66
  67        si_meminfo_node(&i, nid);
  68        n = sprintf(buf,
  69                       "Node %d MemTotal:       %8lu kB\n"
  70                       "Node %d MemFree:        %8lu kB\n"
  71                       "Node %d MemUsed:        %8lu kB\n"
  72                       "Node %d Active:         %8lu kB\n"
  73                       "Node %d Inactive:       %8lu kB\n"
  74                       "Node %d Active(anon):   %8lu kB\n"
  75                       "Node %d Inactive(anon): %8lu kB\n"
  76                       "Node %d Active(file):   %8lu kB\n"
  77                       "Node %d Inactive(file): %8lu kB\n"
  78                       "Node %d Unevictable:    %8lu kB\n"
  79                       "Node %d Mlocked:        %8lu kB\n",
  80                       nid, K(i.totalram),
  81                       nid, K(i.freeram),
  82                       nid, K(i.totalram - i.freeram),
  83                       nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
  84                                node_page_state(nid, NR_ACTIVE_FILE)),
  85                       nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
  86                                node_page_state(nid, NR_INACTIVE_FILE)),
  87                       nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
  88                       nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
  89                       nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
  90                       nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
  91                       nid, K(node_page_state(nid, NR_UNEVICTABLE)),
  92                       nid, K(node_page_state(nid, NR_MLOCK)));
  93
  94#ifdef CONFIG_HIGHMEM
  95        n += sprintf(buf + n,
  96                       "Node %d HighTotal:      %8lu kB\n"
  97                       "Node %d HighFree:       %8lu kB\n"
  98                       "Node %d LowTotal:       %8lu kB\n"
  99                       "Node %d LowFree:        %8lu kB\n",
 100                       nid, K(i.totalhigh),
 101                       nid, K(i.freehigh),
 102                       nid, K(i.totalram - i.totalhigh),
 103                       nid, K(i.freeram - i.freehigh));
 104#endif
 105        n += sprintf(buf + n,
 106                       "Node %d Dirty:          %8lu kB\n"
 107                       "Node %d Writeback:      %8lu kB\n"
 108                       "Node %d FilePages:      %8lu kB\n"
 109                       "Node %d Mapped:         %8lu kB\n"
 110                       "Node %d AnonPages:      %8lu kB\n"
 111                       "Node %d Shmem:          %8lu kB\n"
 112                       "Node %d KernelStack:    %8lu kB\n"
 113                       "Node %d PageTables:     %8lu kB\n"
 114                       "Node %d NFS_Unstable:   %8lu kB\n"
 115                       "Node %d Bounce:         %8lu kB\n"
 116                       "Node %d WritebackTmp:   %8lu kB\n"
 117                       "Node %d Slab:           %8lu kB\n"
 118                       "Node %d SReclaimable:   %8lu kB\n"
 119                       "Node %d SUnreclaim:     %8lu kB\n"
 120#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 121                       "Node %d AnonHugePages:  %8lu kB\n"
 122#endif
 123                        ,
 124                       nid, K(node_page_state(nid, NR_FILE_DIRTY)),
 125                       nid, K(node_page_state(nid, NR_WRITEBACK)),
 126                       nid, K(node_page_state(nid, NR_FILE_PAGES)),
 127                       nid, K(node_page_state(nid, NR_FILE_MAPPED)),
 128#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 129                       nid, K(node_page_state(nid, NR_ANON_PAGES)
 130                        + node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
 131                        HPAGE_PMD_NR),
 132#else
 133                       nid, K(node_page_state(nid, NR_ANON_PAGES)),
 134#endif
 135                       nid, K(node_page_state(nid, NR_SHMEM)),
 136                       nid, node_page_state(nid, NR_KERNEL_STACK) *
 137                                THREAD_SIZE / 1024,
 138                       nid, K(node_page_state(nid, NR_PAGETABLE)),
 139                       nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
 140                       nid, K(node_page_state(nid, NR_BOUNCE)),
 141                       nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
 142                       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
 143                                node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
 144                       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
 145#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 146                       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
 147                        , nid,
 148                        K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
 149                        HPAGE_PMD_NR));
 150#else
 151                       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
 152#endif
 153        n += hugetlb_report_node_meminfo(nid, buf + n);
 154        return n;
 155}
 156
 157#undef K
 158static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);
 159
 160static ssize_t node_read_numastat(struct device *dev,
 161                                struct device_attribute *attr, char *buf)
 162{
 163        return sprintf(buf,
 164                       "numa_hit %lu\n"
 165                       "numa_miss %lu\n"
 166                       "numa_foreign %lu\n"
 167                       "interleave_hit %lu\n"
 168                       "local_node %lu\n"
 169                       "other_node %lu\n",
 170                       node_page_state(dev->id, NUMA_HIT),
 171                       node_page_state(dev->id, NUMA_MISS),
 172                       node_page_state(dev->id, NUMA_FOREIGN),
 173                       node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
 174                       node_page_state(dev->id, NUMA_LOCAL),
 175                       node_page_state(dev->id, NUMA_OTHER));
 176}
 177static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 178
 179static ssize_t node_read_vmstat(struct device *dev,
 180                                struct device_attribute *attr, char *buf)
 181{
 182        int nid = dev->id;
 183        int i;
 184        int n = 0;
 185
 186        for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 187                n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
 188                             node_page_state(nid, i));
 189
 190        return n;
 191}
 192static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);
 193
 194static ssize_t node_read_distance(struct device *dev,
 195                        struct device_attribute *attr, char * buf)
 196{
 197        int nid = dev->id;
 198        int len = 0;
 199        int i;
 200
 201        /*
 202         * buf is currently PAGE_SIZE in length and each node needs 4 chars
 203         * at the most (distance + space or newline).
 204         */
 205        BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 206
 207        for_each_online_node(i)
 208                len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
 209
 210        len += sprintf(buf + len, "\n");
 211        return len;
 212}
 213static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 214
 215#ifdef CONFIG_HUGETLBFS
 216/*
 217 * hugetlbfs per node attributes registration interface:
 218 * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 219 * it will register its per node attributes for all online nodes with
 220 * memory.  It will also call register_hugetlbfs_with_node(), below, to
 221 * register its attribute registration functions with this node driver.
 222 * Once these hooks have been initialized, the node driver will call into
 223 * the hugetlb module to [un]register attributes for hot-plugged nodes.
 224 */
 225static node_registration_func_t __hugetlb_register_node;
 226static node_registration_func_t __hugetlb_unregister_node;
 227
 228static inline bool hugetlb_register_node(struct node *node)
 229{
 230        if (__hugetlb_register_node &&
 231                        node_state(node->dev.id, N_MEMORY)) {
 232                __hugetlb_register_node(node);
 233                return true;
 234        }
 235        return false;
 236}
 237
 238static inline void hugetlb_unregister_node(struct node *node)
 239{
 240        if (__hugetlb_unregister_node)
 241                __hugetlb_unregister_node(node);
 242}
 243
 244void register_hugetlbfs_with_node(node_registration_func_t doregister,
 245                                  node_registration_func_t unregister)
 246{
 247        __hugetlb_register_node   = doregister;
 248        __hugetlb_unregister_node = unregister;
 249}
 250#else
 251static inline void hugetlb_register_node(struct node *node) {}
 252
 253static inline void hugetlb_unregister_node(struct node *node) {}
 254#endif
 255
 256static void node_device_release(struct device *dev)
 257{
 258        struct node *node = to_node(dev);
 259
 260#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
 261        /*
 262         * We schedule the work only when a memory section is
 263         * onlined/offlined on this node. When we come here,
 264         * all the memory on this node has been offlined,
 265         * so we won't enqueue new work to this work.
 266         *
 267         * The work is using node->node_work, so we should
 268         * flush work before freeing the memory.
 269         */
 270        flush_work(&node->node_work);
 271#endif
 272        kfree(node);
 273}
 274
 275/*
 276 * register_node - Setup a sysfs device for a node.
 277 * @num - Node number to use when creating the device.
 278 *
 279 * Initialize and register the node device.
 280 */
 281static int register_node(struct node *node, int num, struct node *parent)
 282{
 283        int error;
 284
 285        node->dev.id = num;
 286        node->dev.bus = &node_subsys;
 287        node->dev.release = node_device_release;
 288        error = device_register(&node->dev);
 289
 290        if (!error){
 291                device_create_file(&node->dev, &dev_attr_cpumap);
 292                device_create_file(&node->dev, &dev_attr_cpulist);
 293                device_create_file(&node->dev, &dev_attr_meminfo);
 294                device_create_file(&node->dev, &dev_attr_numastat);
 295                device_create_file(&node->dev, &dev_attr_distance);
 296                device_create_file(&node->dev, &dev_attr_vmstat);
 297
 298                scan_unevictable_register_node(node);
 299
 300                hugetlb_register_node(node);
 301
 302                compaction_register_node(node);
 303        }
 304        return error;
 305}
 306
 307/**
 308 * unregister_node - unregister a node device
 309 * @node: node going away
 310 *
 311 * Unregisters a node device @node.  All the devices on the node must be
 312 * unregistered before calling this function.
 313 */
 314void unregister_node(struct node *node)
 315{
 316        device_remove_file(&node->dev, &dev_attr_cpumap);
 317        device_remove_file(&node->dev, &dev_attr_cpulist);
 318        device_remove_file(&node->dev, &dev_attr_meminfo);
 319        device_remove_file(&node->dev, &dev_attr_numastat);
 320        device_remove_file(&node->dev, &dev_attr_distance);
 321        device_remove_file(&node->dev, &dev_attr_vmstat);
 322
 323        scan_unevictable_unregister_node(node);
 324        hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 325
 326        device_unregister(&node->dev);
 327}
 328
 329struct node *node_devices[MAX_NUMNODES];
 330
 331/*
 332 * register cpu under node
 333 */
 334int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 335{
 336        int ret;
 337        struct device *obj;
 338
 339        if (!node_online(nid))
 340                return 0;
 341
 342        obj = get_cpu_device(cpu);
 343        if (!obj)
 344                return 0;
 345
 346        ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 347                                &obj->kobj,
 348                                kobject_name(&obj->kobj));
 349        if (ret)
 350                return ret;
 351
 352        return sysfs_create_link(&obj->kobj,
 353                                 &node_devices[nid]->dev.kobj,
 354                                 kobject_name(&node_devices[nid]->dev.kobj));
 355}
 356
 357int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 358{
 359        struct device *obj;
 360
 361        if (!node_online(nid))
 362                return 0;
 363
 364        obj = get_cpu_device(cpu);
 365        if (!obj)
 366                return 0;
 367
 368        sysfs_remove_link(&node_devices[nid]->dev.kobj,
 369                          kobject_name(&obj->kobj));
 370        sysfs_remove_link(&obj->kobj,
 371                          kobject_name(&node_devices[nid]->dev.kobj));
 372
 373        return 0;
 374}
 375
 376#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 377#define page_initialized(page)  (page->lru.next)
 378
 379static int get_nid_for_pfn(unsigned long pfn)
 380{
 381        struct page *page;
 382
 383        if (!pfn_valid_within(pfn))
 384                return -1;
 385        page = pfn_to_page(pfn);
 386        if (!page_initialized(page))
 387                return -1;
 388        return pfn_to_nid(pfn);
 389}
 390
 391/* register memory section under specified node if it spans that node */
 392int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 393{
 394        int ret;
 395        unsigned long pfn, sect_start_pfn, sect_end_pfn;
 396
 397        if (!mem_blk)
 398                return -EFAULT;
 399        if (!node_online(nid))
 400                return 0;
 401
 402        sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 403        sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
 404        sect_end_pfn += PAGES_PER_SECTION - 1;
 405        for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 406                int page_nid;
 407
 408                page_nid = get_nid_for_pfn(pfn);
 409                if (page_nid < 0)
 410                        continue;
 411                if (page_nid != nid)
 412                        continue;
 413                ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 414                                        &mem_blk->dev.kobj,
 415                                        kobject_name(&mem_blk->dev.kobj));
 416                if (ret)
 417                        return ret;
 418
 419                return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 420                                &node_devices[nid]->dev.kobj,
 421                                kobject_name(&node_devices[nid]->dev.kobj));
 422        }
 423        /* mem section does not span the specified node */
 424        return 0;
 425}
 426
 427/* unregister memory section under all nodes that it spans */
 428int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
 429                                    unsigned long phys_index)
 430{
 431        NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
 432        unsigned long pfn, sect_start_pfn, sect_end_pfn;
 433
 434        if (!mem_blk) {
 435                NODEMASK_FREE(unlinked_nodes);
 436                return -EFAULT;
 437        }
 438        if (!unlinked_nodes)
 439                return -ENOMEM;
 440        nodes_clear(*unlinked_nodes);
 441
 442        sect_start_pfn = section_nr_to_pfn(phys_index);
 443        sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
 444        for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
 445                int nid;
 446
 447                nid = get_nid_for_pfn(pfn);
 448                if (nid < 0)
 449                        continue;
 450                if (!node_online(nid))
 451                        continue;
 452                if (node_test_and_set(nid, *unlinked_nodes))
 453                        continue;
 454                sysfs_remove_link(&node_devices[nid]->dev.kobj,
 455                         kobject_name(&mem_blk->dev.kobj));
 456                sysfs_remove_link(&mem_blk->dev.kobj,
 457                         kobject_name(&node_devices[nid]->dev.kobj));
 458        }
 459        NODEMASK_FREE(unlinked_nodes);
 460        return 0;
 461}
 462
 463static int link_mem_sections(int nid)
 464{
 465        unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
 466        unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_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 */
 505static 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
 521static void init_node_hugetlb_work(int nid)
 522{
 523        INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work);
 524}
 525
 526static 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#else   /* !CONFIG_MEMORY_HOTPLUG_SPARSE */
 555
 556static int link_mem_sections(int nid) { return 0; }
 557#endif  /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 558
 559#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
 560    !defined(CONFIG_HUGETLBFS)
 561static inline int node_memory_callback(struct notifier_block *self,
 562                                unsigned long action, void *arg)
 563{
 564        return NOTIFY_OK;
 565}
 566
 567static void init_node_hugetlb_work(int nid) { }
 568
 569#endif
 570
 571int register_one_node(int nid)
 572{
 573        int error = 0;
 574        int cpu;
 575
 576        if (node_online(nid)) {
 577                int p_node = parent_node(nid);
 578                struct node *parent = NULL;
 579
 580                if (p_node != nid)
 581                        parent = node_devices[p_node];
 582
 583                node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 584                if (!node_devices[nid])
 585                        return -ENOMEM;
 586
 587                error = register_node(node_devices[nid], nid, parent);
 588
 589                /* link cpu under this node */
 590                for_each_present_cpu(cpu) {
 591                        if (cpu_to_node(cpu) == nid)
 592                                register_cpu_under_node(cpu, nid);
 593                }
 594
 595                /* link memory sections under this node */
 596                error = link_mem_sections(nid);
 597
 598                /* initialize work queue for memory hot plug */
 599                init_node_hugetlb_work(nid);
 600        }
 601
 602        return error;
 603
 604}
 605
 606void unregister_one_node(int nid)
 607{
 608        unregister_node(node_devices[nid]);
 609        node_devices[nid] = NULL;
 610}
 611
 612/*
 613 * node states attributes
 614 */
 615
 616static ssize_t print_nodes_state(enum node_states state, char *buf)
 617{
 618        int n;
 619
 620        n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]);
 621        buf[n++] = '\n';
 622        buf[n] = '\0';
 623        return n;
 624}
 625
 626struct node_attr {
 627        struct device_attribute attr;
 628        enum node_states state;
 629};
 630
 631static ssize_t show_node_state(struct device *dev,
 632                               struct device_attribute *attr, char *buf)
 633{
 634        struct node_attr *na = container_of(attr, struct node_attr, attr);
 635        return print_nodes_state(na->state, buf);
 636}
 637
 638#define _NODE_ATTR(name, state) \
 639        { __ATTR(name, 0444, show_node_state, NULL), state }
 640
 641static struct node_attr node_state_attr[] = {
 642        [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 643        [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 644        [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 645#ifdef CONFIG_HIGHMEM
 646        [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 647#endif
 648#ifdef CONFIG_MOVABLE_NODE
 649        [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 650#endif
 651        [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 652};
 653
 654static struct attribute *node_state_attrs[] = {
 655        &node_state_attr[N_POSSIBLE].attr.attr,
 656        &node_state_attr[N_ONLINE].attr.attr,
 657        &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 658#ifdef CONFIG_HIGHMEM
 659        &node_state_attr[N_HIGH_MEMORY].attr.attr,
 660#endif
 661#ifdef CONFIG_MOVABLE_NODE
 662        &node_state_attr[N_MEMORY].attr.attr,
 663#endif
 664        &node_state_attr[N_CPU].attr.attr,
 665        NULL
 666};
 667
 668static struct attribute_group memory_root_attr_group = {
 669        .attrs = node_state_attrs,
 670};
 671
 672static const struct attribute_group *cpu_root_attr_groups[] = {
 673        &memory_root_attr_group,
 674        NULL,
 675};
 676
 677#define NODE_CALLBACK_PRI       2       /* lower than SLAB */
 678static int __init register_node_type(void)
 679{
 680        int ret;
 681
 682        BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 683        BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 684
 685        ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 686        if (!ret) {
 687                static struct notifier_block node_memory_callback_nb = {
 688                        .notifier_call = node_memory_callback,
 689                        .priority = NODE_CALLBACK_PRI,
 690                };
 691                register_hotmemory_notifier(&node_memory_callback_nb);
 692        }
 693
 694        /*
 695         * Note:  we're not going to unregister the node class if we fail
 696         * to register the node state class attribute files.
 697         */
 698        return ret;
 699}
 700postcore_initcall(register_node_type);
 701
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