arch/x86/mm/numa_64.c

   1 /*
   2  * Generic VM initialization for x86-64 NUMA setups.
   3  * Copyright 2002,2003 Andi Kleen, SuSE Labs.
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/mm.h>
   7 #include <linux/string.h>
   8 #include <linux/init.h>
   9 #include <linux/bootmem.h>
  10 #include <linux/mmzone.h>
  11 #include <linux/ctype.h>
  12 #include <linux/module.h>
  13 #include <linux/nodemask.h>
  14 #include <linux/sched.h>
  15
  16 #include <asm/e820.h>
  17 #include <asm/proto.h>
  18 #include <asm/dma.h>
  19 #include <asm/numa.h>
  20 #include <asm/acpi.h>
  21 #include <asm/k8.h>
  22
  23 #ifndef Dprintk
  24 #define Dprintk(x...)
  25 #endif
  26
  27 struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
  28 EXPORT_SYMBOL(node_data);
  29
  30 bootmem_data_t plat_node_bdata[MAX_NUMNODES];
  31
  32 struct memnode memnode;
  33
  34 int x86_cpu_to_node_map_init[NR_CPUS] = {
  35         [0 ... NR_CPUS-1] = NUMA_NO_NODE
  36 };
  37 void *x86_cpu_to_node_map_early_ptr;
  38 DEFINE_PER_CPU(int, x86_cpu_to_node_map) = NUMA_NO_NODE;
  39 EXPORT_PER_CPU_SYMBOL(x86_cpu_to_node_map);
  40 EXPORT_SYMBOL(x86_cpu_to_node_map_early_ptr);
  41
  42 s16 apicid_to_node[MAX_LOCAL_APIC] __cpuinitdata = {
  43         [0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE
  44 };
  45
  46 cpumask_t node_to_cpumask_map[MAX_NUMNODES] __read_mostly;
  47 EXPORT_SYMBOL(node_to_cpumask_map);
  48
  49 int numa_off __initdata;
  50 unsigned long __initdata nodemap_addr;
  51 unsigned long __initdata nodemap_size;
  52
  53 /*
  54  * Given a shift value, try to populate memnodemap[]
  55  * Returns :
  56  * 1 if OK
  57  * 0 if memnodmap[] too small (of shift too small)
  58  * -1 if node overlap or lost ram (shift too big)
  59  */
  60 static int __init populate_memnodemap(const struct bootnode *nodes,
  61                                       int numnodes, int shift)
  62 {
  63         unsigned long addr, end;
  64         int i, res = -1;
  65
  66         memset(memnodemap, 0xff, sizeof(s16)*memnodemapsize);
  67         for (i = 0; i < numnodes; i++) {
  68                 addr = nodes[i].start;
  69                 end = nodes[i].end;
  70                 if (addr >= end)
  71                         continue;
  72                 if ((end >> shift) >= memnodemapsize)
  73                         return 0;
  74                 do {
  75                         if (memnodemap[addr >> shift] != NUMA_NO_NODE)
  76                                 return -1;
  77                         memnodemap[addr >> shift] = i;
  78                         addr += (1UL << shift);
  79                 } while (addr < end);
  80                 res = 1;
  81         }
  82         return res;
  83 }
  84
  85 static int __init allocate_cachealigned_memnodemap(void)
  86 {
  87         unsigned long addr;
  88
  89         memnodemap = memnode.embedded_map;
  90         if (memnodemapsize <= ARRAY_SIZE(memnode.embedded_map))
  91                 return 0;
  92
  93         addr = 0x8000;
  94         nodemap_size = round_up(sizeof(s16) * memnodemapsize, L1_CACHE_BYTES);
  95         nodemap_addr = find_e820_area(addr, end_pfn<<PAGE_SHIFT,
  96                                       nodemap_size, L1_CACHE_BYTES);
  97         if (nodemap_addr == -1UL) {
  98                 printk(KERN_ERR
  99                        "NUMA: Unable to allocate Memory to Node hash map\n");
 100                 nodemap_addr = nodemap_size = 0;
 101                 return -1;
 102         }
 103         memnodemap = phys_to_virt(nodemap_addr);
 104         reserve_early(nodemap_addr, nodemap_addr + nodemap_size, "MEMNODEMAP");
 105
 106         printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
 107                nodemap_addr, nodemap_addr + nodemap_size);
 108         return 0;
 109 }
 110
 111 /*
 112  * The LSB of all start and end addresses in the node map is the value of the
 113  * maximum possible shift.
 114  */
 115 static int __init extract_lsb_from_nodes(const struct bootnode *nodes,
 116                                          int numnodes)
 117 {
 118         int i, nodes_used = 0;
 119         unsigned long start, end;
 120         unsigned long bitfield = 0, memtop = 0;
 121
 122         for (i = 0; i < numnodes; i++) {
 123                 start = nodes[i].start;
 124                 end = nodes[i].end;
 125                 if (start >= end)
 126                         continue;
 127                 bitfield |= start;
 128                 nodes_used++;
 129                 if (end > memtop)
 130                         memtop = end;
 131         }
 132         if (nodes_used <= 1)
 133                 i = 63;
 134         else
 135                 i = find_first_bit(&bitfield, sizeof(unsigned long)*8);
 136         memnodemapsize = (memtop >> i)+1;
 137         return i;
 138 }
 139
 140 int __init compute_hash_shift(struct bootnode *nodes, int numnodes)
 141 {
 142         int shift;
 143
 144         shift = extract_lsb_from_nodes(nodes, numnodes);
 145         if (allocate_cachealigned_memnodemap())
 146                 return -1;
 147         printk(KERN_DEBUG "NUMA: Using %d for the hash shift.\n",
 148                 shift);
 149
 150         if (populate_memnodemap(nodes, numnodes, shift) != 1) {
 151                 printk(KERN_INFO "Your memory is not aligned you need to "
 152                        "rebuild your kernel with a bigger NODEMAPSIZE "
 153                        "shift=%d\n", shift);
 154                 return -1;
 155         }
 156         return shift;
 157 }
 158
 159 int early_pfn_to_nid(unsigned long pfn)
 160 {
 161         return phys_to_nid(pfn << PAGE_SHIFT);
 162 }
 163
 164 static void * __init early_node_mem(int nodeid, unsigned long start,
 165                                     unsigned long end, unsigned long size,
 166                                     unsigned long align)
 167 {
 168         unsigned long mem = find_e820_area(start, end, size, align);
 169         void *ptr;
 170
 171         if (mem != -1L)
 172                 return __va(mem);
 173
 174         ptr = __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
 175         if (ptr == NULL) {
 176                 printk(KERN_ERR "Cannot find %lu bytes in node %d\n",
 177                        size, nodeid);
 178                 return NULL;
 179         }
 180         return ptr;
 181 }
 182
 183 /* Initialize bootmem allocator for a node */
 184 void __init setup_node_bootmem(int nodeid, unsigned long start,
 185                                unsigned long end)
 186 {
 187         unsigned long start_pfn, end_pfn, bootmap_pages, bootmap_size;
 188         unsigned long bootmap_start, nodedata_phys;
 189         void *bootmap;
 190         const int pgdat_size = round_up(sizeof(pg_data_t), PAGE_SIZE);
 191
 192         start = round_up(start, ZONE_ALIGN);
 193
 194         printk(KERN_INFO "Bootmem setup node %d %016lx-%016lx\n", nodeid,
 195                start, end);
 196
 197         start_pfn = start >> PAGE_SHIFT;
 198         end_pfn = end >> PAGE_SHIFT;
 199
 200         node_data[nodeid] = early_node_mem(nodeid, start, end, pgdat_size,
 201                                            SMP_CACHE_BYTES);
 202         if (node_data[nodeid] == NULL)
 203                 return;
 204         nodedata_phys = __pa(node_data[nodeid]);
 205         printk(KERN_INFO "  NODE_DATA [%016lx - %016lx]\n", nodedata_phys,
 206                 nodedata_phys + pgdat_size - 1);
 207
 208         memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t));
 209         NODE_DATA(nodeid)->bdata = &plat_node_bdata[nodeid];
 210         NODE_DATA(nodeid)->node_start_pfn = start_pfn;
 211         NODE_DATA(nodeid)->node_spanned_pages = end_pfn - start_pfn;
 212
 213         /* Find a place for the bootmem map */
 214         bootmap_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
 215         bootmap_start = round_up(nodedata_phys + pgdat_size, PAGE_SIZE);
 216         /*
 217          * SMP_CAHCE_BYTES could be enough, but init_bootmem_node like
 218          * to use that to align to PAGE_SIZE
 219          */
 220         bootmap = early_node_mem(nodeid, bootmap_start, end,
 221                                  bootmap_pages<<PAGE_SHIFT, PAGE_SIZE);
 222         if (bootmap == NULL)  {
 223                 if (nodedata_phys < start || nodedata_phys >= end)
 224                         free_bootmem((unsigned long)node_data[nodeid],
 225                                      pgdat_size);
 226                 node_data[nodeid] = NULL;
 227                 return;
 228         }
 229         bootmap_start = __pa(bootmap);
 230
 231         bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
 232                                          bootmap_start >> PAGE_SHIFT,
 233                                          start_pfn, end_pfn);
 234
 235         printk(KERN_INFO "  bootmap [%016lx -  %016lx] pages %lx\n",
 236                  bootmap_start, bootmap_start + bootmap_size - 1,
 237                  bootmap_pages);
 238
 239         free_bootmem_with_active_regions(nodeid, end);
 240
 241         reserve_bootmem_node(NODE_DATA(nodeid), nodedata_phys, pgdat_size,
 242                         BOOTMEM_DEFAULT);
 243         reserve_bootmem_node(NODE_DATA(nodeid), bootmap_start,
 244                         bootmap_pages<<PAGE_SHIFT, BOOTMEM_DEFAULT);
 245 #ifdef CONFIG_ACPI_NUMA
 246         srat_reserve_add_area(nodeid);
 247 #endif
 248         node_set_online(nodeid);
 249 }
 250
 251 /*
 252  * There are unfortunately some poorly designed mainboards around that
 253  * only connect memory to a single CPU. This breaks the 1:1 cpu->node
 254  * mapping. To avoid this fill in the mapping for all possible CPUs,
 255  * as the number of CPUs is not known yet. We round robin the existing
 256  * nodes.
 257  */
 258 void __init numa_init_array(void)
 259 {
 260         int rr, i;
 261
 262         rr = first_node(node_online_map);
 263         for (i = 0; i < NR_CPUS; i++) {
 264                 if (early_cpu_to_node(i) != NUMA_NO_NODE)
 265                         continue;
 266                 numa_set_node(i, rr);
 267                 rr = next_node(rr, node_online_map);
 268                 if (rr == MAX_NUMNODES)
 269                         rr = first_node(node_online_map);
 270         }
 271 }
 272
 273 #ifdef CONFIG_NUMA_EMU
 274 /* Numa emulation */
 275 char *cmdline __initdata;
 276
 277 /*
 278  * Setups up nid to range from addr to addr + size.  If the end
 279  * boundary is greater than max_addr, then max_addr is used instead.
 280  * The return value is 0 if there is additional memory left for
 281  * allocation past addr and -1 otherwise.  addr is adjusted to be at
 282  * the end of the node.
 283  */
 284 static int __init setup_node_range(int nid, struct bootnode *nodes, u64 *addr,
 285                                    u64 size, u64 max_addr)
 286 {
 287         int ret = 0;
 288
 289         nodes[nid].start = *addr;
 290         *addr += size;
 291         if (*addr >= max_addr) {
 292                 *addr = max_addr;
 293                 ret = -1;
 294         }
 295         nodes[nid].end = *addr;
 296         node_set(nid, node_possible_map);
 297         printk(KERN_INFO "Faking node %d at %016Lx-%016Lx (%LuMB)\n", nid,
 298                nodes[nid].start, nodes[nid].end,
 299                (nodes[nid].end - nodes[nid].start) >> 20);
 300         return ret;
 301 }
 302
 303 /*
 304  * Splits num_nodes nodes up equally starting at node_start.  The return value
 305  * is the number of nodes split up and addr is adjusted to be at the end of the
 306  * last node allocated.
 307  */
 308 static int __init split_nodes_equally(struct bootnode *nodes, u64 *addr,
 309                                       u64 max_addr, int node_start,
 310                                       int num_nodes)
 311 {
 312         unsigned int big;
 313         u64 size;
 314         int i;
 315
 316         if (num_nodes <= 0)
 317                 return -1;
 318         if (num_nodes > MAX_NUMNODES)
 319                 num_nodes = MAX_NUMNODES;
 320         size = (max_addr - *addr - e820_hole_size(*addr, max_addr)) /
 321                num_nodes;
 322         /*
 323          * Calculate the number of big nodes that can be allocated as a result
 324          * of consolidating the leftovers.
 325          */
 326         big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * num_nodes) /
 327               FAKE_NODE_MIN_SIZE;
 328
 329         /* Round down to nearest FAKE_NODE_MIN_SIZE. */
 330         size &= FAKE_NODE_MIN_HASH_MASK;
 331         if (!size) {
 332                 printk(KERN_ERR "Not enough memory for each node.  "
 333                        "NUMA emulation disabled.\n");
 334                 return -1;
 335         }
 336
 337         for (i = node_start; i < num_nodes + node_start; i++) {
 338                 u64 end = *addr + size;
 339
 340                 if (i < big)
 341                         end += FAKE_NODE_MIN_SIZE;
 342                 /*
 343                  * The final node can have the remaining system RAM.  Other
 344                  * nodes receive roughly the same amount of available pages.
 345                  */
 346                 if (i == num_nodes + node_start - 1)
 347                         end = max_addr;
 348                 else
 349                         while (end - *addr - e820_hole_size(*addr, end) <
 350                                size) {
 351                                 end += FAKE_NODE_MIN_SIZE;
 352                                 if (end > max_addr) {
 353                                         end = max_addr;
 354                                         break;
 355                                 }
 356                         }
 357                 if (setup_node_range(i, nodes, addr, end - *addr, max_addr) < 0)
 358                         break;
 359         }
 360         return i - node_start + 1;
 361 }
 362
 363 /*
 364  * Splits the remaining system RAM into chunks of size.  The remaining memory is
 365  * always assigned to a final node and can be asymmetric.  Returns the number of
 366  * nodes split.
 367  */
 368 static int __init split_nodes_by_size(struct bootnode *nodes, u64 *addr,
 369                                       u64 max_addr, int node_start, u64 size)
 370 {
 371         int i = node_start;
 372         size = (size << 20) & FAKE_NODE_MIN_HASH_MASK;
 373         while (!setup_node_range(i++, nodes, addr, size, max_addr))
 374                 ;
 375         return i - node_start;
 376 }
 377
 378 /*
 379  * Sets up the system RAM area from start_pfn to end_pfn according to the
 380  * numa=fake command-line option.
 381  */
 382 static int __init numa_emulation(unsigned long start_pfn, unsigned long end_pfn)
 383 {
 384         struct bootnode nodes[MAX_NUMNODES];
 385         u64 size, addr = start_pfn << PAGE_SHIFT;
 386         u64 max_addr = end_pfn << PAGE_SHIFT;
 387         int num_nodes = 0, num = 0, coeff_flag, coeff = -1, i;
 388
 389         memset(&nodes, 0, sizeof(nodes));
 390         /*
 391          * If the numa=fake command-line is just a single number N, split the
 392          * system RAM into N fake nodes.
 393          */
 394         if (!strchr(cmdline, '*') && !strchr(cmdline, ',')) {
 395                 long n = simple_strtol(cmdline, NULL, 0);
 396
 397                 num_nodes = split_nodes_equally(nodes, &addr, max_addr, 0, n);
 398                 if (num_nodes < 0)
 399                         return num_nodes;
 400                 goto out;
 401         }
 402
 403         /* Parse the command line. */
 404         for (coeff_flag = 0; ; cmdline++) {
 405                 if (*cmdline && isdigit(*cmdline)) {
 406                         num = num * 10 + *cmdline - '0';
 407                         continue;
 408                 }
 409                 if (*cmdline == '*') {
 410                         if (num > 0)
 411                                 coeff = num;
 412                         coeff_flag = 1;
 413                 }
 414                 if (!*cmdline || *cmdline == ',') {
 415                         if (!coeff_flag)
 416                                 coeff = 1;
 417                         /*
 418                          * Round down to the nearest FAKE_NODE_MIN_SIZE.
 419                          * Command-line coefficients are in megabytes.
 420                          */
 421                         size = ((u64)num << 20) & FAKE_NODE_MIN_HASH_MASK;
 422                         if (size)
 423                                 for (i = 0; i < coeff; i++, num_nodes++)
 424                                         if (setup_node_range(num_nodes, nodes,
 425                                                 &addr, size, max_addr) < 0)
 426                                                 goto done;
 427                         if (!*cmdline)
 428                                 break;
 429                         coeff_flag = 0;
 430                         coeff = -1;
 431                 }
 432                 num = 0;
 433         }
 434 done:
 435         if (!num_nodes)
 436                 return -1;
 437         /* Fill remainder of system RAM, if appropriate. */
 438         if (addr < max_addr) {
 439                 if (coeff_flag && coeff < 0) {
 440                         /* Split remaining nodes into num-sized chunks */
 441                         num_nodes += split_nodes_by_size(nodes, &addr, max_addr,
 442                                                          num_nodes, num);
 443                         goto out;
 444                 }
 445                 switch (*(cmdline - 1)) {
 446                 case '*':
 447                         /* Split remaining nodes into coeff chunks */
 448                         if (coeff <= 0)
 449                                 break;
 450                         num_nodes += split_nodes_equally(nodes, &addr, max_addr,
 451                                                          num_nodes, coeff);
 452                         break;
 453                 case ',':
 454                         /* Do not allocate remaining system RAM */
 455                         break;
 456                 default:
 457                         /* Give one final node */
 458                         setup_node_range(num_nodes, nodes, &addr,
 459                                          max_addr - addr, max_addr);
 460                         num_nodes++;
 461                 }
 462         }
 463 out:
 464         memnode_shift = compute_hash_shift(nodes, num_nodes);
 465         if (memnode_shift < 0) {
 466                 memnode_shift = 0;
 467                 printk(KERN_ERR "No NUMA hash function found.  NUMA emulation "
 468                        "disabled.\n");
 469                 return -1;
 470         }
 471
 472         /*
 473          * We need to vacate all active ranges that may have been registered by
 474          * SRAT and set acpi_numa to -1 so that srat_disabled() always returns
 475          * true.  NUMA emulation has succeeded so we will not scan ACPI nodes.
 476          */
 477         remove_all_active_ranges();
 478 #ifdef CONFIG_ACPI_NUMA
 479         acpi_numa = -1;
 480 #endif
 481         for_each_node_mask(i, node_possible_map) {
 482                 e820_register_active_regions(i, nodes[i].start >> PAGE_SHIFT,
 483                                                 nodes[i].end >> PAGE_SHIFT);
 484                 setup_node_bootmem(i, nodes[i].start, nodes[i].end);
 485         }
 486         acpi_fake_nodes(nodes, num_nodes);
 487         numa_init_array();
 488         return 0;
 489 }
 490 #endif /* CONFIG_NUMA_EMU */
 491
 492 void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
 493 {
 494         int i;
 495
 496         nodes_clear(node_possible_map);
 497         nodes_clear(node_online_map);
 498
 499 #ifdef CONFIG_NUMA_EMU
 500         if (cmdline && !numa_emulation(start_pfn, end_pfn))
 501                 return;
 502         nodes_clear(node_possible_map);
 503         nodes_clear(node_online_map);
 504 #endif
 505
 506 #ifdef CONFIG_ACPI_NUMA
 507         if (!numa_off && !acpi_scan_nodes(start_pfn << PAGE_SHIFT,
 508                                           end_pfn << PAGE_SHIFT))
 509                 return;
 510         nodes_clear(node_possible_map);
 511         nodes_clear(node_online_map);
 512 #endif
 513
 514 #ifdef CONFIG_K8_NUMA
 515         if (!numa_off && !k8_scan_nodes(start_pfn<<PAGE_SHIFT,
 516                                         end_pfn<<PAGE_SHIFT))
 517                 return;
 518         nodes_clear(node_possible_map);
 519         nodes_clear(node_online_map);
 520 #endif
 521         printk(KERN_INFO "%s\n",
 522                numa_off ? "NUMA turned off" : "No NUMA configuration found");
 523
 524         printk(KERN_INFO "Faking a node at %016lx-%016lx\n",
 525                start_pfn << PAGE_SHIFT,
 526                end_pfn << PAGE_SHIFT);
 527         /* setup dummy node covering all memory */
 528         memnode_shift = 63;
 529         memnodemap = memnode.embedded_map;
 530         memnodemap[0] = 0;
 531         node_set_online(0);
 532         node_set(0, node_possible_map);
 533         for (i = 0; i < NR_CPUS; i++)
 534                 numa_set_node(i, 0);
 535         /* cpumask_of_cpu() may not be available during early startup */
 536         memset(&node_to_cpumask_map[0], 0, sizeof(node_to_cpumask_map[0]));
 537         cpu_set(0, node_to_cpumask_map[0]);
 538         e820_register_active_regions(0, start_pfn, end_pfn);
 539         setup_node_bootmem(0, start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
 540 }
 541
 542 __cpuinit void numa_add_cpu(int cpu)
 543 {
 544         set_bit(cpu,
 545                 (unsigned long *)&node_to_cpumask_map[early_cpu_to_node(cpu)]);
 546 }
 547
 548 void __cpuinit numa_set_node(int cpu, int node)
 549 {
 550         int *cpu_to_node_map = x86_cpu_to_node_map_early_ptr;
 551
 552         cpu_pda(cpu)->nodenumber = node;
 553
 554         if(cpu_to_node_map)
 555                 cpu_to_node_map[cpu] = node;
 556         else if(per_cpu_offset(cpu))
 557                 per_cpu(x86_cpu_to_node_map, cpu) = node;
 558         else
 559                 Dprintk(KERN_INFO "Setting node for non-present cpu %d\n", cpu);
 560 }
 561
 562 unsigned long __init numa_free_all_bootmem(void)
 563 {
 564         unsigned long pages = 0;
 565         int i;
 566
 567         for_each_online_node(i)
 568                 pages += free_all_bootmem_node(NODE_DATA(i));
 569
 570         return pages;
 571 }
 572
 573 void __init paging_init(void)
 574 {
 575         unsigned long max_zone_pfns[MAX_NR_ZONES];
 576
 577         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 578         max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
 579         max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
 580         max_zone_pfns[ZONE_NORMAL] = end_pfn;
 581
 582         sparse_memory_present_with_active_regions(MAX_NUMNODES);
 583         sparse_init();
 584
 585         free_area_init_nodes(max_zone_pfns);
 586 }
 587
 588 static __init int numa_setup(char *opt)
 589 {
 590         if (!opt)
 591                 return -EINVAL;
 592         if (!strncmp(opt, "off", 3))
 593                 numa_off = 1;
 594 #ifdef CONFIG_NUMA_EMU
 595         if (!strncmp(opt, "fake=", 5))
 596                 cmdline = opt + 5;
 597 #endif
 598 #ifdef CONFIG_ACPI_NUMA
 599         if (!strncmp(opt, "noacpi", 6))
 600                 acpi_numa = -1;
 601         if (!strncmp(opt, "hotadd=", 7))
 602                 hotadd_percent = simple_strtoul(opt+7, NULL, 10);
 603 #endif
 604         return 0;
 605 }
 606 early_param("numa", numa_setup);
 607
 608 /*
 609  * Setup early cpu_to_node.
 610  *
 611  * Populate cpu_to_node[] only if x86_cpu_to_apicid[],
 612  * and apicid_to_node[] tables have valid entries for a CPU.
 613  * This means we skip cpu_to_node[] initialisation for NUMA
 614  * emulation and faking node case (when running a kernel compiled
 615  * for NUMA on a non NUMA box), which is OK as cpu_to_node[]
 616  * is already initialized in a round robin manner at numa_init_array,
 617  * prior to this call, and this initialization is good enough
 618  * for the fake NUMA cases.
 619  */
 620 void __init init_cpu_to_node(void)
 621 {
 622         int i;
 623
 624         for (i = 0; i < NR_CPUS; i++) {
 625                 int node;
 626                 u16 apicid = x86_cpu_to_apicid_init[i];
 627
 628                 if (apicid == BAD_APICID)
 629                         continue;
 630                 node = apicid_to_node[apicid];
 631                 if (node == NUMA_NO_NODE)
 632                         continue;
 633                 if (!node_online(node))
 634                         continue;
 635                 numa_set_node(i, node);
 636         }
 637 }
 638
 639