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/pm_runtime.h>
  21 #include <linux/swap.h>
  22 #include <linux/slab.h>
  23 #include <linux/hugetlb.h>
  24
  25 static struct bus_type node_subsys = {
  26         .name = "node",
  27         .dev_name = "node",
  28 };
  29
  30 static inline ssize_t cpumap_read(struct file *file, struct kobject *kobj,
  31                                   struct bin_attribute *attr, char *buf,
  32                                   loff_t off, size_t count)
  33 {
  34         struct device *dev = kobj_to_dev(kobj);
  35         struct node *node_dev = to_node(dev);
  36         cpumask_var_t mask;
  37         ssize_t n;
  38
  39         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  40                 return 0;
  41
  42         cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
  43         n = cpumap_print_bitmask_to_buf(buf, mask, off, count);
  44         free_cpumask_var(mask);
  45
  46         return n;
  47 }
  48
  49 static BIN_ATTR_RO(cpumap, CPUMAP_FILE_MAX_BYTES);
  50
  51 static inline ssize_t cpulist_read(struct file *file, struct kobject *kobj,
  52                                    struct bin_attribute *attr, char *buf,
  53                                    loff_t off, size_t count)
  54 {
  55         struct device *dev = kobj_to_dev(kobj);
  56         struct node *node_dev = to_node(dev);
  57         cpumask_var_t mask;
  58         ssize_t n;
  59
  60         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  61                 return 0;
  62
  63         cpumask_and(mask, cpumask_of_node(node_dev->dev.id), cpu_online_mask);
  64         n = cpumap_print_list_to_buf(buf, mask, off, count);
  65         free_cpumask_var(mask);
  66
  67         return n;
  68 }
  69
  70 static BIN_ATTR_RO(cpulist, CPULIST_FILE_MAX_BYTES);
  71
  72 /**
  73  * struct node_access_nodes - Access class device to hold user visible
  74  *                            relationships to other nodes.
  75  * @dev:        Device for this memory access class
  76  * @list_node:  List element in the node's access list
  77  * @access:     The access class rank
  78  * @hmem_attrs: Heterogeneous memory performance attributes
  79  */
  80 struct node_access_nodes {
  81         struct device           dev;
  82         struct list_head        list_node;
  83         unsigned int            access;
  84 #ifdef CONFIG_HMEM_REPORTING
  85         struct node_hmem_attrs  hmem_attrs;
  86 #endif
  87 };
  88 #define to_access_nodes(dev) container_of(dev, struct node_access_nodes, dev)
  89
  90 static struct attribute *node_init_access_node_attrs[] = {
  91         NULL,
  92 };
  93
  94 static struct attribute *node_targ_access_node_attrs[] = {
  95         NULL,
  96 };
  97
  98 static const struct attribute_group initiators = {
  99         .name   = "initiators",
 100         .attrs  = node_init_access_node_attrs,
 101 };
 102
 103 static const struct attribute_group targets = {
 104         .name   = "targets",
 105         .attrs  = node_targ_access_node_attrs,
 106 };
 107
 108 static const struct attribute_group *node_access_node_groups[] = {
 109         &initiators,
 110         &targets,
 111         NULL,
 112 };
 113
 114 static void node_remove_accesses(struct node *node)
 115 {
 116         struct node_access_nodes *c, *cnext;
 117
 118         list_for_each_entry_safe(c, cnext, &node->access_list, list_node) {
 119                 list_del(&c->list_node);
 120                 device_unregister(&c->dev);
 121         }
 122 }
 123
 124 static void node_access_release(struct device *dev)
 125 {
 126         kfree(to_access_nodes(dev));
 127 }
 128
 129 static struct node_access_nodes *node_init_node_access(struct node *node,
 130                                                        unsigned int access)
 131 {
 132         struct node_access_nodes *access_node;
 133         struct device *dev;
 134
 135         list_for_each_entry(access_node, &node->access_list, list_node)
 136                 if (access_node->access == access)
 137                         return access_node;
 138
 139         access_node = kzalloc(sizeof(*access_node), GFP_KERNEL);
 140         if (!access_node)
 141                 return NULL;
 142
 143         access_node->access = access;
 144         dev = &access_node->dev;
 145         dev->parent = &node->dev;
 146         dev->release = node_access_release;
 147         dev->groups = node_access_node_groups;
 148         if (dev_set_name(dev, "access%u", access))
 149                 goto free;
 150
 151         if (device_register(dev))
 152                 goto free_name;
 153
 154         pm_runtime_no_callbacks(dev);
 155         list_add_tail(&access_node->list_node, &node->access_list);
 156         return access_node;
 157 free_name:
 158         kfree_const(dev->kobj.name);
 159 free:
 160         kfree(access_node);
 161         return NULL;
 162 }
 163
 164 #ifdef CONFIG_HMEM_REPORTING
 165 #define ACCESS_ATTR(name)                                               \
 166 static ssize_t name##_show(struct device *dev,                          \
 167                            struct device_attribute *attr,               \
 168                            char *buf)                                   \
 169 {                                                                       \
 170         return sysfs_emit(buf, "%u\n",                                  \
 171                           to_access_nodes(dev)->hmem_attrs.name);       \
 172 }                                                                       \
 173 static DEVICE_ATTR_RO(name)
 174
 175 ACCESS_ATTR(read_bandwidth);
 176 ACCESS_ATTR(read_latency);
 177 ACCESS_ATTR(write_bandwidth);
 178 ACCESS_ATTR(write_latency);
 179
 180 static struct attribute *access_attrs[] = {
 181         &dev_attr_read_bandwidth.attr,
 182         &dev_attr_read_latency.attr,
 183         &dev_attr_write_bandwidth.attr,
 184         &dev_attr_write_latency.attr,
 185         NULL,
 186 };
 187
 188 /**
 189  * node_set_perf_attrs - Set the performance values for given access class
 190  * @nid: Node identifier to be set
 191  * @hmem_attrs: Heterogeneous memory performance attributes
 192  * @access: The access class the for the given attributes
 193  */
 194 void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs,
 195                          unsigned int access)
 196 {
 197         struct node_access_nodes *c;
 198         struct node *node;
 199         int i;
 200
 201         if (WARN_ON_ONCE(!node_online(nid)))
 202                 return;
 203
 204         node = node_devices[nid];
 205         c = node_init_node_access(node, access);
 206         if (!c)
 207                 return;
 208
 209         c->hmem_attrs = *hmem_attrs;
 210         for (i = 0; access_attrs[i] != NULL; i++) {
 211                 if (sysfs_add_file_to_group(&c->dev.kobj, access_attrs[i],
 212                                             "initiators")) {
 213                         pr_info("failed to add performance attribute to node %d\n",
 214                                 nid);
 215                         break;
 216                 }
 217         }
 218 }
 219
 220 /**
 221  * struct node_cache_info - Internal tracking for memory node caches
 222  * @dev:        Device represeting the cache level
 223  * @node:       List element for tracking in the node
 224  * @cache_attrs:Attributes for this cache level
 225  */
 226 struct node_cache_info {
 227         struct device dev;
 228         struct list_head node;
 229         struct node_cache_attrs cache_attrs;
 230 };
 231 #define to_cache_info(device) container_of(device, struct node_cache_info, dev)
 232
 233 #define CACHE_ATTR(name, fmt)                                           \
 234 static ssize_t name##_show(struct device *dev,                          \
 235                            struct device_attribute *attr,               \
 236                            char *buf)                                   \
 237 {                                                                       \
 238         return sysfs_emit(buf, fmt "\n",                                \
 239                           to_cache_info(dev)->cache_attrs.name);        \
 240 }                                                                       \
 241 static DEVICE_ATTR_RO(name);
 242
 243 CACHE_ATTR(size, "%llu")
 244 CACHE_ATTR(line_size, "%u")
 245 CACHE_ATTR(indexing, "%u")
 246 CACHE_ATTR(write_policy, "%u")
 247
 248 static struct attribute *cache_attrs[] = {
 249         &dev_attr_indexing.attr,
 250         &dev_attr_size.attr,
 251         &dev_attr_line_size.attr,
 252         &dev_attr_write_policy.attr,
 253         NULL,
 254 };
 255 ATTRIBUTE_GROUPS(cache);
 256
 257 static void node_cache_release(struct device *dev)
 258 {
 259         kfree(dev);
 260 }
 261
 262 static void node_cacheinfo_release(struct device *dev)
 263 {
 264         struct node_cache_info *info = to_cache_info(dev);
 265         kfree(info);
 266 }
 267
 268 static void node_init_cache_dev(struct node *node)
 269 {
 270         struct device *dev;
 271
 272         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 273         if (!dev)
 274                 return;
 275
 276         device_initialize(dev);
 277         dev->parent = &node->dev;
 278         dev->release = node_cache_release;
 279         if (dev_set_name(dev, "memory_side_cache"))
 280                 goto put_device;
 281
 282         if (device_add(dev))
 283                 goto put_device;
 284
 285         pm_runtime_no_callbacks(dev);
 286         node->cache_dev = dev;
 287         return;
 288 put_device:
 289         put_device(dev);
 290 }
 291
 292 /**
 293  * node_add_cache() - add cache attribute to a memory node
 294  * @nid: Node identifier that has new cache attributes
 295  * @cache_attrs: Attributes for the cache being added
 296  */
 297 void node_add_cache(unsigned int nid, struct node_cache_attrs *cache_attrs)
 298 {
 299         struct node_cache_info *info;
 300         struct device *dev;
 301         struct node *node;
 302
 303         if (!node_online(nid) || !node_devices[nid])
 304                 return;
 305
 306         node = node_devices[nid];
 307         list_for_each_entry(info, &node->cache_attrs, node) {
 308                 if (info->cache_attrs.level == cache_attrs->level) {
 309                         dev_warn(&node->dev,
 310                                 "attempt to add duplicate cache level:%d\n",
 311                                 cache_attrs->level);
 312                         return;
 313                 }
 314         }
 315
 316         if (!node->cache_dev)
 317                 node_init_cache_dev(node);
 318         if (!node->cache_dev)
 319                 return;
 320
 321         info = kzalloc(sizeof(*info), GFP_KERNEL);
 322         if (!info)
 323                 return;
 324
 325         dev = &info->dev;
 326         device_initialize(dev);
 327         dev->parent = node->cache_dev;
 328         dev->release = node_cacheinfo_release;
 329         dev->groups = cache_groups;
 330         if (dev_set_name(dev, "index%d", cache_attrs->level))
 331                 goto put_device;
 332
 333         info->cache_attrs = *cache_attrs;
 334         if (device_add(dev)) {
 335                 dev_warn(&node->dev, "failed to add cache level:%d\n",
 336                          cache_attrs->level);
 337                 goto put_device;
 338         }
 339         pm_runtime_no_callbacks(dev);
 340         list_add_tail(&info->node, &node->cache_attrs);
 341         return;
 342 put_device:
 343         put_device(dev);
 344 }
 345
 346 static void node_remove_caches(struct node *node)
 347 {
 348         struct node_cache_info *info, *next;
 349
 350         if (!node->cache_dev)
 351                 return;
 352
 353         list_for_each_entry_safe(info, next, &node->cache_attrs, node) {
 354                 list_del(&info->node);
 355                 device_unregister(&info->dev);
 356         }
 357         device_unregister(node->cache_dev);
 358 }
 359
 360 static void node_init_caches(unsigned int nid)
 361 {
 362         INIT_LIST_HEAD(&node_devices[nid]->cache_attrs);
 363 }
 364 #else
 365 static void node_init_caches(unsigned int nid) { }
 366 static void node_remove_caches(struct node *node) { }
 367 #endif
 368
 369 #define K(x) ((x) << (PAGE_SHIFT - 10))
 370 static ssize_t node_read_meminfo(struct device *dev,
 371                         struct device_attribute *attr, char *buf)
 372 {
 373         int len = 0;
 374         int nid = dev->id;
 375         struct pglist_data *pgdat = NODE_DATA(nid);
 376         struct sysinfo i;
 377         unsigned long sreclaimable, sunreclaimable;
 378         unsigned long swapcached = 0;
 379
 380         si_meminfo_node(&i, nid);
 381         sreclaimable = node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B);
 382         sunreclaimable = node_page_state_pages(pgdat, NR_SLAB_UNRECLAIMABLE_B);
 383 #ifdef CONFIG_SWAP
 384         swapcached = node_page_state_pages(pgdat, NR_SWAPCACHE);
 385 #endif
 386         len = sysfs_emit_at(buf, len,
 387                             "Node %d MemTotal:       %8lu kB\n"
 388                             "Node %d MemFree:        %8lu kB\n"
 389                             "Node %d MemUsed:        %8lu kB\n"
 390                             "Node %d SwapCached:     %8lu kB\n"
 391                             "Node %d Active:         %8lu kB\n"
 392                             "Node %d Inactive:       %8lu kB\n"
 393                             "Node %d Active(anon):   %8lu kB\n"
 394                             "Node %d Inactive(anon): %8lu kB\n"
 395                             "Node %d Active(file):   %8lu kB\n"
 396                             "Node %d Inactive(file): %8lu kB\n"
 397                             "Node %d Unevictable:    %8lu kB\n"
 398                             "Node %d Mlocked:        %8lu kB\n",
 399                             nid, K(i.totalram),
 400                             nid, K(i.freeram),
 401                             nid, K(i.totalram - i.freeram),
 402                             nid, K(swapcached),
 403                             nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
 404                                    node_page_state(pgdat, NR_ACTIVE_FILE)),
 405                             nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
 406                                    node_page_state(pgdat, NR_INACTIVE_FILE)),
 407                             nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
 408                             nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
 409                             nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
 410                             nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
 411                             nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
 412                             nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
 413
 414 #ifdef CONFIG_HIGHMEM
 415         len += sysfs_emit_at(buf, len,
 416                              "Node %d HighTotal:      %8lu kB\n"
 417                              "Node %d HighFree:       %8lu kB\n"
 418                              "Node %d LowTotal:       %8lu kB\n"
 419                              "Node %d LowFree:        %8lu kB\n",
 420                              nid, K(i.totalhigh),
 421                              nid, K(i.freehigh),
 422                              nid, K(i.totalram - i.totalhigh),
 423                              nid, K(i.freeram - i.freehigh));
 424 #endif
 425         len += sysfs_emit_at(buf, len,
 426                              "Node %d Dirty:          %8lu kB\n"
 427                              "Node %d Writeback:      %8lu kB\n"
 428                              "Node %d FilePages:      %8lu kB\n"
 429                              "Node %d Mapped:         %8lu kB\n"
 430                              "Node %d AnonPages:      %8lu kB\n"
 431                              "Node %d Shmem:          %8lu kB\n"
 432                              "Node %d KernelStack:    %8lu kB\n"
 433 #ifdef CONFIG_SHADOW_CALL_STACK
 434                              "Node %d ShadowCallStack:%8lu kB\n"
 435 #endif
 436                              "Node %d PageTables:     %8lu kB\n"
 437                              "Node %d SecPageTables:  %8lu kB\n"
 438                              "Node %d NFS_Unstable:   %8lu kB\n"
 439                              "Node %d Bounce:         %8lu kB\n"
 440                              "Node %d WritebackTmp:   %8lu kB\n"
 441                              "Node %d KReclaimable:   %8lu kB\n"
 442                              "Node %d Slab:           %8lu kB\n"
 443                              "Node %d SReclaimable:   %8lu kB\n"
 444                              "Node %d SUnreclaim:     %8lu kB\n"
 445 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 446                              "Node %d AnonHugePages:  %8lu kB\n"
 447                              "Node %d ShmemHugePages: %8lu kB\n"
 448                              "Node %d ShmemPmdMapped: %8lu kB\n"
 449                              "Node %d FileHugePages: %8lu kB\n"
 450                              "Node %d FilePmdMapped: %8lu kB\n"
 451 #endif
 452                              ,
 453                              nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
 454                              nid, K(node_page_state(pgdat, NR_WRITEBACK)),
 455                              nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
 456                              nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
 457                              nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
 458                              nid, K(i.sharedram),
 459                              nid, node_page_state(pgdat, NR_KERNEL_STACK_KB),
 460 #ifdef CONFIG_SHADOW_CALL_STACK
 461                              nid, node_page_state(pgdat, NR_KERNEL_SCS_KB),
 462 #endif
 463                              nid, K(node_page_state(pgdat, NR_PAGETABLE)),
 464                              nid, K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)),
 465                              nid, 0UL,
 466                              nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
 467                              nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
 468                              nid, K(sreclaimable +
 469                                     node_page_state(pgdat, NR_KERNEL_MISC_RECLAIMABLE)),
 470                              nid, K(sreclaimable + sunreclaimable),
 471                              nid, K(sreclaimable),
 472                              nid, K(sunreclaimable)
 473 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 474                              ,
 475                              nid, K(node_page_state(pgdat, NR_ANON_THPS)),
 476                              nid, K(node_page_state(pgdat, NR_SHMEM_THPS)),
 477                              nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)),
 478                              nid, K(node_page_state(pgdat, NR_FILE_THPS)),
 479                              nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED))
 480 #endif
 481                             );
 482         len += hugetlb_report_node_meminfo(buf, len, nid);
 483         return len;
 484 }
 485
 486 #undef K
 487 static DEVICE_ATTR(meminfo, 0444, node_read_meminfo, NULL);
 488
 489 static ssize_t node_read_numastat(struct device *dev,
 490                                   struct device_attribute *attr, char *buf)
 491 {
 492         fold_vm_numa_events();
 493         return sysfs_emit(buf,
 494                           "numa_hit %lu\n"
 495                           "numa_miss %lu\n"
 496                           "numa_foreign %lu\n"
 497                           "interleave_hit %lu\n"
 498                           "local_node %lu\n"
 499                           "other_node %lu\n",
 500                           sum_zone_numa_event_state(dev->id, NUMA_HIT),
 501                           sum_zone_numa_event_state(dev->id, NUMA_MISS),
 502                           sum_zone_numa_event_state(dev->id, NUMA_FOREIGN),
 503                           sum_zone_numa_event_state(dev->id, NUMA_INTERLEAVE_HIT),
 504                           sum_zone_numa_event_state(dev->id, NUMA_LOCAL),
 505                           sum_zone_numa_event_state(dev->id, NUMA_OTHER));
 506 }
 507 static DEVICE_ATTR(numastat, 0444, node_read_numastat, NULL);
 508
 509 static ssize_t node_read_vmstat(struct device *dev,
 510                                 struct device_attribute *attr, char *buf)
 511 {
 512         int nid = dev->id;
 513         struct pglist_data *pgdat = NODE_DATA(nid);
 514         int i;
 515         int len = 0;
 516
 517         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 518                 len += sysfs_emit_at(buf, len, "%s %lu\n",
 519                                      zone_stat_name(i),
 520                                      sum_zone_node_page_state(nid, i));
 521
 522 #ifdef CONFIG_NUMA
 523         fold_vm_numa_events();
 524         for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
 525                 len += sysfs_emit_at(buf, len, "%s %lu\n",
 526                                      numa_stat_name(i),
 527                                      sum_zone_numa_event_state(nid, i));
 528
 529 #endif
 530         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
 531                 unsigned long pages = node_page_state_pages(pgdat, i);
 532
 533                 if (vmstat_item_print_in_thp(i))
 534                         pages /= HPAGE_PMD_NR;
 535                 len += sysfs_emit_at(buf, len, "%s %lu\n", node_stat_name(i),
 536                                      pages);
 537         }
 538
 539         return len;
 540 }
 541 static DEVICE_ATTR(vmstat, 0444, node_read_vmstat, NULL);
 542
 543 static ssize_t node_read_distance(struct device *dev,
 544                                   struct device_attribute *attr, char *buf)
 545 {
 546         int nid = dev->id;
 547         int len = 0;
 548         int i;
 549
 550         /*
 551          * buf is currently PAGE_SIZE in length and each node needs 4 chars
 552          * at the most (distance + space or newline).
 553          */
 554         BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 555
 556         for_each_online_node(i) {
 557                 len += sysfs_emit_at(buf, len, "%s%d",
 558                                      i ? " " : "", node_distance(nid, i));
 559         }
 560
 561         len += sysfs_emit_at(buf, len, "\n");
 562         return len;
 563 }
 564 static DEVICE_ATTR(distance, 0444, node_read_distance, NULL);
 565
 566 static struct attribute *node_dev_attrs[] = {
 567         &dev_attr_meminfo.attr,
 568         &dev_attr_numastat.attr,
 569         &dev_attr_distance.attr,
 570         &dev_attr_vmstat.attr,
 571         NULL
 572 };
 573
 574 static struct bin_attribute *node_dev_bin_attrs[] = {
 575         &bin_attr_cpumap,
 576         &bin_attr_cpulist,
 577         NULL
 578 };
 579
 580 static const struct attribute_group node_dev_group = {
 581         .attrs = node_dev_attrs,
 582         .bin_attrs = node_dev_bin_attrs
 583 };
 584
 585 static const struct attribute_group *node_dev_groups[] = {
 586         &node_dev_group,
 587 #ifdef CONFIG_HAVE_ARCH_NODE_DEV_GROUP
 588         &arch_node_dev_group,
 589 #endif
 590 #ifdef CONFIG_MEMORY_FAILURE
 591         &memory_failure_attr_group,
 592 #endif
 593         NULL
 594 };
 595
 596 static void node_device_release(struct device *dev)
 597 {
 598         kfree(to_node(dev));
 599 }
 600
 601 /*
 602  * register_node - Setup a sysfs device for a node.
 603  * @num - Node number to use when creating the device.
 604  *
 605  * Initialize and register the node device.
 606  */
 607 static int register_node(struct node *node, int num)
 608 {
 609         int error;
 610
 611         node->dev.id = num;
 612         node->dev.bus = &node_subsys;
 613         node->dev.release = node_device_release;
 614         node->dev.groups = node_dev_groups;
 615         error = device_register(&node->dev);
 616
 617         if (error) {
 618                 put_device(&node->dev);
 619         } else {
 620                 hugetlb_register_node(node);
 621                 compaction_register_node(node);
 622         }
 623
 624         return error;
 625 }
 626
 627 /**
 628  * unregister_node - unregister a node device
 629  * @node: node going away
 630  *
 631  * Unregisters a node device @node.  All the devices on the node must be
 632  * unregistered before calling this function.
 633  */
 634 void unregister_node(struct node *node)
 635 {
 636         hugetlb_unregister_node(node);
 637         compaction_unregister_node(node);
 638         node_remove_accesses(node);
 639         node_remove_caches(node);
 640         device_unregister(&node->dev);
 641 }
 642
 643 struct node *node_devices[MAX_NUMNODES];
 644
 645 /*
 646  * register cpu under node
 647  */
 648 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 649 {
 650         int ret;
 651         struct device *obj;
 652
 653         if (!node_online(nid))
 654                 return 0;
 655
 656         obj = get_cpu_device(cpu);
 657         if (!obj)
 658                 return 0;
 659
 660         ret = sysfs_create_link(&node_devices[nid]->dev.kobj,
 661                                 &obj->kobj,
 662                                 kobject_name(&obj->kobj));
 663         if (ret)
 664                 return ret;
 665
 666         return sysfs_create_link(&obj->kobj,
 667                                  &node_devices[nid]->dev.kobj,
 668                                  kobject_name(&node_devices[nid]->dev.kobj));
 669 }
 670
 671 /**
 672  * register_memory_node_under_compute_node - link memory node to its compute
 673  *                                           node for a given access class.
 674  * @mem_nid:    Memory node number
 675  * @cpu_nid:    Cpu  node number
 676  * @access:     Access class to register
 677  *
 678  * Description:
 679  *      For use with platforms that may have separate memory and compute nodes.
 680  *      This function will export node relationships linking which memory
 681  *      initiator nodes can access memory targets at a given ranked access
 682  *      class.
 683  */
 684 int register_memory_node_under_compute_node(unsigned int mem_nid,
 685                                             unsigned int cpu_nid,
 686                                             unsigned int access)
 687 {
 688         struct node *init_node, *targ_node;
 689         struct node_access_nodes *initiator, *target;
 690         int ret;
 691
 692         if (!node_online(cpu_nid) || !node_online(mem_nid))
 693                 return -ENODEV;
 694
 695         init_node = node_devices[cpu_nid];
 696         targ_node = node_devices[mem_nid];
 697         initiator = node_init_node_access(init_node, access);
 698         target = node_init_node_access(targ_node, access);
 699         if (!initiator || !target)
 700                 return -ENOMEM;
 701
 702         ret = sysfs_add_link_to_group(&initiator->dev.kobj, "targets",
 703                                       &targ_node->dev.kobj,
 704                                       dev_name(&targ_node->dev));
 705         if (ret)
 706                 return ret;
 707
 708         ret = sysfs_add_link_to_group(&target->dev.kobj, "initiators",
 709                                       &init_node->dev.kobj,
 710                                       dev_name(&init_node->dev));
 711         if (ret)
 712                 goto err;
 713
 714         return 0;
 715  err:
 716         sysfs_remove_link_from_group(&initiator->dev.kobj, "targets",
 717                                      dev_name(&targ_node->dev));
 718         return ret;
 719 }
 720
 721 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 722 {
 723         struct device *obj;
 724
 725         if (!node_online(nid))
 726                 return 0;
 727
 728         obj = get_cpu_device(cpu);
 729         if (!obj)
 730                 return 0;
 731
 732         sysfs_remove_link(&node_devices[nid]->dev.kobj,
 733                           kobject_name(&obj->kobj));
 734         sysfs_remove_link(&obj->kobj,
 735                           kobject_name(&node_devices[nid]->dev.kobj));
 736
 737         return 0;
 738 }
 739
 740 #ifdef CONFIG_MEMORY_HOTPLUG
 741 static int __ref get_nid_for_pfn(unsigned long pfn)
 742 {
 743 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 744         if (system_state < SYSTEM_RUNNING)
 745                 return early_pfn_to_nid(pfn);
 746 #endif
 747         return pfn_to_nid(pfn);
 748 }
 749
 750 static void do_register_memory_block_under_node(int nid,
 751                                                 struct memory_block *mem_blk,
 752                                                 enum meminit_context context)
 753 {
 754         int ret;
 755
 756         memory_block_add_nid(mem_blk, nid, context);
 757
 758         ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
 759                                        &mem_blk->dev.kobj,
 760                                        kobject_name(&mem_blk->dev.kobj));
 761         if (ret && ret != -EEXIST)
 762                 dev_err_ratelimited(&node_devices[nid]->dev,
 763                                     "can't create link to %s in sysfs (%d)\n",
 764                                     kobject_name(&mem_blk->dev.kobj), ret);
 765
 766         ret = sysfs_create_link_nowarn(&mem_blk->dev.kobj,
 767                                 &node_devices[nid]->dev.kobj,
 768                                 kobject_name(&node_devices[nid]->dev.kobj));
 769         if (ret && ret != -EEXIST)
 770                 dev_err_ratelimited(&mem_blk->dev,
 771                                     "can't create link to %s in sysfs (%d)\n",
 772                                     kobject_name(&node_devices[nid]->dev.kobj),
 773                                     ret);
 774 }
 775
 776 /* register memory section under specified node if it spans that node */
 777 static int register_mem_block_under_node_early(struct memory_block *mem_blk,
 778                                                void *arg)
 779 {
 780         unsigned long memory_block_pfns = memory_block_size_bytes() / PAGE_SIZE;
 781         unsigned long start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
 782         unsigned long end_pfn = start_pfn + memory_block_pfns - 1;
 783         int nid = *(int *)arg;
 784         unsigned long pfn;
 785
 786         for (pfn = start_pfn; pfn <= end_pfn; pfn++) {
 787                 int page_nid;
 788
 789                 /*
 790                  * memory block could have several absent sections from start.
 791                  * skip pfn range from absent section
 792                  */
 793                 if (!pfn_in_present_section(pfn)) {
 794                         pfn = round_down(pfn + PAGES_PER_SECTION,
 795                                          PAGES_PER_SECTION) - 1;
 796                         continue;
 797                 }
 798
 799                 /*
 800                  * We need to check if page belongs to nid only at the boot
 801                  * case because node's ranges can be interleaved.
 802                  */
 803                 page_nid = get_nid_for_pfn(pfn);
 804                 if (page_nid < 0)
 805                         continue;
 806                 if (page_nid != nid)
 807                         continue;
 808
 809                 do_register_memory_block_under_node(nid, mem_blk, MEMINIT_EARLY);
 810                 return 0;
 811         }
 812         /* mem section does not span the specified node */
 813         return 0;
 814 }
 815
 816 /*
 817  * During hotplug we know that all pages in the memory block belong to the same
 818  * node.
 819  */
 820 static int register_mem_block_under_node_hotplug(struct memory_block *mem_blk,
 821                                                  void *arg)
 822 {
 823         int nid = *(int *)arg;
 824
 825         do_register_memory_block_under_node(nid, mem_blk, MEMINIT_HOTPLUG);
 826         return 0;
 827 }
 828
 829 /*
 830  * Unregister a memory block device under the node it spans. Memory blocks
 831  * with multiple nodes cannot be offlined and therefore also never be removed.
 832  */
 833 void unregister_memory_block_under_nodes(struct memory_block *mem_blk)
 834 {
 835         if (mem_blk->nid == NUMA_NO_NODE)
 836                 return;
 837
 838         sysfs_remove_link(&node_devices[mem_blk->nid]->dev.kobj,
 839                           kobject_name(&mem_blk->dev.kobj));
 840         sysfs_remove_link(&mem_blk->dev.kobj,
 841                           kobject_name(&node_devices[mem_blk->nid]->dev.kobj));
 842 }
 843
 844 void register_memory_blocks_under_node(int nid, unsigned long start_pfn,
 845                                        unsigned long end_pfn,
 846                                        enum meminit_context context)
 847 {
 848         walk_memory_blocks_func_t func;
 849
 850         if (context == MEMINIT_HOTPLUG)
 851                 func = register_mem_block_under_node_hotplug;
 852         else
 853                 func = register_mem_block_under_node_early;
 854
 855         walk_memory_blocks(PFN_PHYS(start_pfn), PFN_PHYS(end_pfn - start_pfn),
 856                            (void *)&nid, func);
 857         return;
 858 }
 859 #endif /* CONFIG_MEMORY_HOTPLUG */
 860
 861 int __register_one_node(int nid)
 862 {
 863         int error;
 864         int cpu;
 865
 866         node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 867         if (!node_devices[nid])
 868                 return -ENOMEM;
 869
 870         error = register_node(node_devices[nid], nid);
 871
 872         /* link cpu under this node */
 873         for_each_present_cpu(cpu) {
 874                 if (cpu_to_node(cpu) == nid)
 875                         register_cpu_under_node(cpu, nid);
 876         }
 877
 878         INIT_LIST_HEAD(&node_devices[nid]->access_list);
 879         node_init_caches(nid);
 880
 881         return error;
 882 }
 883
 884 void unregister_one_node(int nid)
 885 {
 886         if (!node_devices[nid])
 887                 return;
 888
 889         unregister_node(node_devices[nid]);
 890         node_devices[nid] = NULL;
 891 }
 892
 893 /*
 894  * node states attributes
 895  */
 896
 897 struct node_attr {
 898         struct device_attribute attr;
 899         enum node_states state;
 900 };
 901
 902 static ssize_t show_node_state(struct device *dev,
 903                                struct device_attribute *attr, char *buf)
 904 {
 905         struct node_attr *na = container_of(attr, struct node_attr, attr);
 906
 907         return sysfs_emit(buf, "%*pbl\n",
 908                           nodemask_pr_args(&node_states[na->state]));
 909 }
 910
 911 #define _NODE_ATTR(name, state) \
 912         { __ATTR(name, 0444, show_node_state, NULL), state }
 913
 914 static struct node_attr node_state_attr[] = {
 915         [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
 916         [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
 917         [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
 918 #ifdef CONFIG_HIGHMEM
 919         [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 920 #endif
 921         [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 922         [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
 923         [N_GENERIC_INITIATOR] = _NODE_ATTR(has_generic_initiator,
 924                                            N_GENERIC_INITIATOR),
 925 };
 926
 927 static struct attribute *node_state_attrs[] = {
 928         &node_state_attr[N_POSSIBLE].attr.attr,
 929         &node_state_attr[N_ONLINE].attr.attr,
 930         &node_state_attr[N_NORMAL_MEMORY].attr.attr,
 931 #ifdef CONFIG_HIGHMEM
 932         &node_state_attr[N_HIGH_MEMORY].attr.attr,
 933 #endif
 934         &node_state_attr[N_MEMORY].attr.attr,
 935         &node_state_attr[N_CPU].attr.attr,
 936         &node_state_attr[N_GENERIC_INITIATOR].attr.attr,
 937         NULL
 938 };
 939
 940 static const struct attribute_group memory_root_attr_group = {
 941         .attrs = node_state_attrs,
 942 };
 943
 944 static const struct attribute_group *cpu_root_attr_groups[] = {
 945         &memory_root_attr_group,
 946         NULL,
 947 };
 948
 949 void __init node_dev_init(void)
 950 {
 951         int ret, i;
 952
 953         BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
 954         BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 955
 956         ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
 957         if (ret)
 958                 panic("%s() failed to register subsystem: %d\n", __func__, ret);
 959
 960         /*
 961          * Create all node devices, which will properly link the node
 962          * to applicable memory block devices and already created cpu devices.
 963          */
 964         for_each_online_node(i) {
 965                 ret = register_one_node(i);
 966                 if (ret)
 967                         panic("%s() failed to add node: %d\n", __func__, ret);
 968         }
 969 }