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 #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 158 static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL); 159 160 static 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 } 177 static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL); 178 179 static 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 } 192 static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL); 193 194 static 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 } 213 static 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 */ 225 static node_registration_func_t __hugetlb_register_node; 226 static node_registration_func_t __hugetlb_unregister_node; 227 228 static 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 } 237 238 static inline void hugetlb_unregister_node(struct node *node) 239 { 240 if (__hugetlb_unregister_node) 241 __hugetlb_unregister_node(node); 242 } 243 244 void 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 251 static inline void hugetlb_register_node(struct node *node) {} 252 253 static inline void hugetlb_unregister_node(struct node *node) {} 254 #endif 255 256 static 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 */ 281 static 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 */ 314 void 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 } 328 329 struct node *node_devices[MAX_NUMNODES]; 330 331 /* 332 * register cpu under node 333 */ 334 int 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 } 356 357 int 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) 378 379 static 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 */ 392 int 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 */ 428 int 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 } 462 463 static 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 */ 505 static void node_hugetlb_work(struct work_struct *work) 506 { 507 struct node *node = container_of(work, struct node, node_work); 508 509 /* 510 * We only get here when a node transitions to/from memoryless state. 511 * We can detect which transition occurred by examining whether the 512 * node has memory now. hugetlb_register_node() already check this 513 * so we try to register the attributes. If that fails, then the 514 * node has transitioned to memoryless, try to unregister the 515 * attributes. 516 */ 517 if (!hugetlb_register_node(node)) 518 hugetlb_unregister_node(node); 519 } 520 521 static void init_node_hugetlb_work(int nid) 522 { 523 INIT_WORK(&node_devices[nid]->node_work, node_hugetlb_work); 524 } 525 526 static int node_memory_callback(struct notifier_block *self, 527 unsigned long action, void *arg) 528 { 529 struct memory_notify *mnb = arg; 530 int nid = mnb->status_change_nid; 531 532 switch (action) { 533 case MEM_ONLINE: 534 case MEM_OFFLINE: 535 /* 536 * offload per node hstate [un]registration to a work thread 537 * when transitioning to/from memoryless state. 538 */ 539 if (nid != NUMA_NO_NODE) 540 schedule_work(&node_devices[nid]->node_work); 541 break; 542 543 case MEM_GOING_ONLINE: 544 case MEM_GOING_OFFLINE: 545 case MEM_CANCEL_ONLINE: 546 case MEM_CANCEL_OFFLINE: 547 default: 548 break; 549 } 550 551 return NOTIFY_OK; 552 } 553 #endif /* CONFIG_HUGETLBFS */ 554 #else /* !CONFIG_MEMORY_HOTPLUG_SPARSE */ 555 556 static 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) 561 static inline int node_memory_callback(struct notifier_block *self, 562 unsigned long action, void *arg) 563 { 564 return NOTIFY_OK; 565 } 566 567 static void init_node_hugetlb_work(int nid) { } 568 569 #endif 570 571 int 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 } 605 606 void 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 */ 615 616 static 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 } 625 626 struct node_attr { 627 struct device_attribute attr; 628 enum node_states state; 629 }; 630 631 static 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 } 640 641 static 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 }; 653 654 static 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 }; 667 668 static struct attribute_group memory_root_attr_group = { 669 .attrs = node_state_attrs, 670 }; 671 672 static 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 */ 678 static 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 } 700 postcore_initcall(register_node_type); 701