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, 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 45 static 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 } 50 static 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 56 static DEVICE_ATTR(cpumap, S_IRUGO, node_read_cpumask, NULL); 57 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL); 58 59 #define K(x) ((x) << (PAGE_SHIFT - 10)) 60 static 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 nid, K(node_page_state(nid, NR_ANON_PAGES)), 129 nid, K(node_page_state(nid, NR_SHMEM)), 130 nid, node_page_state(nid, NR_KERNEL_STACK) * 131 THREAD_SIZE / 1024, 132 nid, K(node_page_state(nid, NR_PAGETABLE)), 133 nid, K(node_page_state(nid, NR_UNSTABLE_NFS)), 134 nid, K(node_page_state(nid, NR_BOUNCE)), 135 nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)), 136 nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) + 137 node_page_state(nid, NR_SLAB_UNRECLAIMABLE)), 138 nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)), 139 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 140 nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)) 141 , nid, 142 K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) * 143 HPAGE_PMD_NR)); 144 #else 145 nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))); 146 #endif 147 n += hugetlb_report_node_meminfo(nid, buf + n); 148 return n; 149 } 150 151 #undef K 152 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL); 153 154 static ssize_t node_read_numastat(struct device *dev, 155 struct device_attribute *attr, char *buf) 156 { 157 return sprintf(buf, 158 "numa_hit %lu\n" 159 "numa_miss %lu\n" 160 "numa_foreign %lu\n" 161 "interleave_hit %lu\n" 162 "local_node %lu\n" 163 "other_node %lu\n", 164 node_page_state(dev->id, NUMA_HIT), 165 node_page_state(dev->id, NUMA_MISS), 166 node_page_state(dev->id, NUMA_FOREIGN), 167 node_page_state(dev->id, NUMA_INTERLEAVE_HIT), 168 node_page_state(dev->id, NUMA_LOCAL), 169 node_page_state(dev->id, NUMA_OTHER)); 170 } 171 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL); 172 173 static ssize_t node_read_vmstat(struct device *dev, 174 struct device_attribute *attr, char *buf) 175 { 176 int nid = dev->id; 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 node_page_state(nid, i)); 183 184 return n; 185 } 186 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL); 187 188 static ssize_t node_read_distance(struct device *dev, 189 struct device_attribute *attr, char * buf) 190 { 191 int nid = dev->id; 192 int len = 0; 193 int i; 194 195 /* 196 * buf is currently PAGE_SIZE in length and each node needs 4 chars 197 * at the most (distance + space or newline). 198 */ 199 BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE); 200 201 for_each_online_node(i) 202 len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i)); 203 204 len += sprintf(buf + len, "\n"); 205 return len; 206 } 207 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL); 208 209 #ifdef CONFIG_HUGETLBFS 210 /* 211 * hugetlbfs per node attributes registration interface: 212 * When/if hugetlb[fs] subsystem initializes [sometime after this module], 213 * it will register its per node attributes for all online nodes with 214 * memory. It will also call register_hugetlbfs_with_node(), below, to 215 * register its attribute registration functions with this node driver. 216 * Once these hooks have been initialized, the node driver will call into 217 * the hugetlb module to [un]register attributes for hot-plugged nodes. 218 */ 219 static node_registration_func_t __hugetlb_register_node; 220 static node_registration_func_t __hugetlb_unregister_node; 221 222 static inline bool hugetlb_register_node(struct node *node) 223 { 224 if (__hugetlb_register_node && 225 node_state(node->dev.id, N_MEMORY)) { 226 __hugetlb_register_node(node); 227 return true; 228 } 229 return false; 230 } 231 232 static inline void hugetlb_unregister_node(struct node *node) 233 { 234 if (__hugetlb_unregister_node) 235 __hugetlb_unregister_node(node); 236 } 237 238 void register_hugetlbfs_with_node(node_registration_func_t doregister, 239 node_registration_func_t unregister) 240 { 241 __hugetlb_register_node = doregister; 242 __hugetlb_unregister_node = unregister; 243 } 244 #else 245 static inline void hugetlb_register_node(struct node *node) {} 246 247 static inline void hugetlb_unregister_node(struct node *node) {} 248 #endif 249 250 static void node_device_release(struct device *dev) 251 { 252 struct node *node = to_node(dev); 253 254 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS) 255 /* 256 * We schedule the work only when a memory section is 257 * onlined/offlined on this node. When we come here, 258 * all the memory on this node has been offlined, 259 * so we won't enqueue new work to this work. 260 * 261 * The work is using node->node_work, so we should 262 * flush work before freeing the memory. 263 */ 264 flush_work(&node->node_work); 265 #endif 266 kfree(node); 267 } 268 269 /* 270 * register_node - Setup a sysfs device for a node. 271 * @num - Node number to use when creating the device. 272 * 273 * Initialize and register the node device. 274 */ 275 static int register_node(struct node *node, int num, struct node *parent) 276 { 277 int error; 278 279 node->dev.id = num; 280 node->dev.bus = &node_subsys; 281 node->dev.release = node_device_release; 282 error = device_register(&node->dev); 283 284 if (!error){ 285 device_create_file(&node->dev, &dev_attr_cpumap); 286 device_create_file(&node->dev, &dev_attr_cpulist); 287 device_create_file(&node->dev, &dev_attr_meminfo); 288 device_create_file(&node->dev, &dev_attr_numastat); 289 device_create_file(&node->dev, &dev_attr_distance); 290 device_create_file(&node->dev, &dev_attr_vmstat); 291 292 scan_unevictable_register_node(node); 293 294 hugetlb_register_node(node); 295 296 compaction_register_node(node); 297 } 298 return error; 299 } 300 301 /** 302 * unregister_node - unregister a node device 303 * @node: node going away 304 * 305 * Unregisters a node device @node. All the devices on the node must be 306 * unregistered before calling this function. 307 */ 308 void unregister_node(struct node *node) 309 { 310 device_remove_file(&node->dev, &dev_attr_cpumap); 311 device_remove_file(&node->dev, &dev_attr_cpulist); 312 device_remove_file(&node->dev, &dev_attr_meminfo); 313 device_remove_file(&node->dev, &dev_attr_numastat); 314 device_remove_file(&node->dev, &dev_attr_distance); 315 device_remove_file(&node->dev, &dev_attr_vmstat); 316 317 scan_unevictable_unregister_node(node); 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 #define page_initialized(page) (page->lru.next) 372 373 static int get_nid_for_pfn(unsigned long pfn) 374 { 375 struct page *page; 376 377 if (!pfn_valid_within(pfn)) 378 return -1; 379 page = pfn_to_page(pfn); 380 if (!page_initialized(page)) 381 return -1; 382 return pfn_to_nid(pfn); 383 } 384 385 /* register memory section under specified node if it spans that node */ 386 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid) 387 { 388 int ret; 389 unsigned long pfn, sect_start_pfn, sect_end_pfn; 390 391 if (!mem_blk) 392 return -EFAULT; 393 if (!node_online(nid)) 394 return 0; 395 396 sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); 397 sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); 398 sect_end_pfn += PAGES_PER_SECTION - 1; 399 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 400 int page_nid; 401 402 page_nid = get_nid_for_pfn(pfn); 403 if (page_nid < 0) 404 continue; 405 if (page_nid != nid) 406 continue; 407 ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj, 408 &mem_blk->dev.kobj, 409 kobject_name(&mem_blk->dev.kobj)); 410 if (ret) 411 return ret; 412 413 return sysfs_create_link_nowarn(&mem_blk->dev.kobj, 414 &node_devices[nid]->dev.kobj, 415 kobject_name(&node_devices[nid]->dev.kobj)); 416 } 417 /* mem section does not span the specified node */ 418 return 0; 419 } 420 421 /* unregister memory section under all nodes that it spans */ 422 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk, 423 unsigned long phys_index) 424 { 425 NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL); 426 unsigned long pfn, sect_start_pfn, sect_end_pfn; 427 428 if (!mem_blk) { 429 NODEMASK_FREE(unlinked_nodes); 430 return -EFAULT; 431 } 432 if (!unlinked_nodes) 433 return -ENOMEM; 434 nodes_clear(*unlinked_nodes); 435 436 sect_start_pfn = section_nr_to_pfn(phys_index); 437 sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1; 438 for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { 439 int nid; 440 441 nid = get_nid_for_pfn(pfn); 442 if (nid < 0) 443 continue; 444 if (!node_online(nid)) 445 continue; 446 if (node_test_and_set(nid, *unlinked_nodes)) 447 continue; 448 sysfs_remove_link(&node_devices[nid]->dev.kobj, 449 kobject_name(&mem_blk->dev.kobj)); 450 sysfs_remove_link(&mem_blk->dev.kobj, 451 kobject_name(&node_devices[nid]->dev.kobj)); 452 } 453 NODEMASK_FREE(unlinked_nodes); 454 return 0; 455 } 456 457 static int link_mem_sections(int nid) 458 { 459 unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn; 460 unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages; 461 unsigned long pfn; 462 struct memory_block *mem_blk = NULL; 463 int err = 0; 464 465 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 466 unsigned long section_nr = pfn_to_section_nr(pfn); 467 struct mem_section *mem_sect; 468 int ret; 469 470 if (!present_section_nr(section_nr)) 471 continue; 472 mem_sect = __nr_to_section(section_nr); 473 474 /* same memblock ? */ 475 if (mem_blk) 476 if ((section_nr >= mem_blk->start_section_nr) && 477 (section_nr <= mem_blk->end_section_nr)) 478 continue; 479 480 mem_blk = find_memory_block_hinted(mem_sect, mem_blk); 481 482 ret = register_mem_sect_under_node(mem_blk, nid); 483 if (!err) 484 err = ret; 485 486 /* discard ref obtained in find_memory_block() */ 487 } 488 489 if (mem_blk) 490 kobject_put(&mem_blk->dev.kobj); 491 return err; 492 } 493 494 #ifdef CONFIG_HUGETLBFS 495 /* 496 * Handle per node hstate attribute [un]registration on transistions 497 * to/from memoryless state. 498 */ 499 static void node_hugetlb_work(struct work_struct *work) 500 { 501 struct node *node = container_of(work, struct node, node_work); 502 503 /* 504 * We only get here when a node transitions to/from memoryless state. 505 * We can detect which transition occurred by examining whether the 506 * node has memory now. hugetlb_register_node() already check this 507 * so we try to register the attributes. If that fails, then the 508 * node has transitioned to memoryless, try to unregister the 509 * attributes. 510 */ 511 if (!hugetlb_register_node(node)) 512 hugetlb_unregister_node(node); 513 } 514 515 static void init_node_hugetlb_work(int nid) 516 { 517 INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work); 518 } 519 520 static int node_memory_callback(struct notifier_block *self, 521 unsigned long action, void *arg) 522 { 523 struct memory_notify *mnb = arg; 524 int nid = mnb->status_change_nid; 525 526 switch (action) { 527 case MEM_ONLINE: 528 case MEM_OFFLINE: 529 /* 530 * offload per node hstate [un]registration to a work thread 531 * when transitioning to/from memoryless state. 532 */ 533 if (nid != NUMA_NO_NODE) 534 schedule_work(&node_devices[nid]->node_work); 535 break; 536 537 case MEM_GOING_ONLINE: 538 case MEM_GOING_OFFLINE: 539 case MEM_CANCEL_ONLINE: 540 case MEM_CANCEL_OFFLINE: 541 default: 542 break; 543 } 544 545 return NOTIFY_OK; 546 } 547 #endif /* CONFIG_HUGETLBFS */ 548 #else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */ 549 550 static int link_mem_sections(int nid) { return 0; } 551 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 552 553 #if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \ 554 !defined(CONFIG_HUGETLBFS) 555 static inline int node_memory_callback(struct notifier_block *self, 556 unsigned long action, void *arg) 557 { 558 return NOTIFY_OK; 559 } 560 561 static void init_node_hugetlb_work(int nid) { } 562 563 #endif 564 565 int register_one_node(int nid) 566 { 567 int error = 0; 568 int cpu; 569 570 if (node_online(nid)) { 571 int p_node = parent_node(nid); 572 struct node *parent = NULL; 573 574 if (p_node != nid) 575 parent = node_devices[p_node]; 576 577 node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL); 578 if (!node_devices[nid]) 579 return -ENOMEM; 580 581 error = register_node(node_devices[nid], nid, parent); 582 583 /* link cpu under this node */ 584 for_each_present_cpu(cpu) { 585 if (cpu_to_node(cpu) == nid) 586 register_cpu_under_node(cpu, nid); 587 } 588 589 /* link memory sections under this node */ 590 error = link_mem_sections(nid); 591 592 /* initialize work queue for memory hot plug */ 593 init_node_hugetlb_work(nid); 594 } 595 596 return error; 597 598 } 599 600 void unregister_one_node(int nid) 601 { 602 if (!node_devices[nid]) 603 return; 604 605 unregister_node(node_devices[nid]); 606 kfree(node_devices[nid]); 607 node_devices[nid] = NULL; 608 } 609 610 /* 611 * node states attributes 612 */ 613 614 static ssize_t print_nodes_state(enum node_states state, char *buf) 615 { 616 int n; 617 618 n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]); 619 buf[n++] = '\n'; 620 buf[n] = '\0'; 621 return n; 622 } 623 624 struct node_attr { 625 struct device_attribute attr; 626 enum node_states state; 627 }; 628 629 static ssize_t show_node_state(struct device *dev, 630 struct device_attribute *attr, char *buf) 631 { 632 struct node_attr *na = container_of(attr, struct node_attr, attr); 633 return print_nodes_state(na->state, buf); 634 } 635 636 #define _NODE_ATTR(name, state) \ 637 { __ATTR(name, 0444, show_node_state, NULL), state } 638 639 static struct node_attr node_state_attr[] = { 640 [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE), 641 [N_ONLINE] = _NODE_ATTR(online, N_ONLINE), 642 [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY), 643 #ifdef CONFIG_HIGHMEM 644 [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY), 645 #endif 646 #ifdef CONFIG_MOVABLE_NODE 647 [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY), 648 #endif 649 [N_CPU] = _NODE_ATTR(has_cpu, N_CPU), 650 }; 651 652 static struct attribute *node_state_attrs[] = { 653 &node_state_attr[N_POSSIBLE].attr.attr, 654 &node_state_attr[N_ONLINE].attr.attr, 655 &node_state_attr[N_NORMAL_MEMORY].attr.attr, 656 #ifdef CONFIG_HIGHMEM 657 &node_state_attr[N_HIGH_MEMORY].attr.attr, 658 #endif 659 #ifdef CONFIG_MOVABLE_NODE 660 &node_state_attr[N_MEMORY].attr.attr, 661 #endif 662 &node_state_attr[N_CPU].attr.attr, 663 NULL 664 }; 665 666 static struct attribute_group memory_root_attr_group = { 667 .attrs = node_state_attrs, 668 }; 669 670 static const struct attribute_group *cpu_root_attr_groups[] = { 671 &memory_root_attr_group, 672 NULL, 673 }; 674 675 #define NODE_CALLBACK_PRI 2 /* lower than SLAB */ 676 static int __init register_node_type(void) 677 { 678 int ret; 679 680 BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES); 681 BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES); 682 683 ret = subsys_system_register(&node_subsys, cpu_root_attr_groups); 684 if (!ret) { 685 static struct notifier_block node_memory_callback_nb = { 686 .notifier_call = node_memory_callback, 687 .priority = NODE_CALLBACK_PRI, 688 }; 689 register_hotmemory_notifier(&node_memory_callback_nb); 690 } 691 692 /* 693 * Note: we're not going to unregister the node class if we fail 694 * to register the node state class attribute files. 695 */ 696 return ret; 697 } 698 postcore_initcall(register_node_type); 699