mm/sparse.c

   1 /*
   2  * sparse memory mappings.
   3  */
   4 #include <linux/mm.h>
   5 #include <linux/slab.h>
   6 #include <linux/mmzone.h>
   7 #include <linux/bootmem.h>
   8 #include <linux/compiler.h>
   9 #include <linux/highmem.h>
  10 #include <linux/export.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/vmalloc.h>
  13
  14 #include "internal.h"
  15 #include <asm/dma.h>
  16 #include <asm/pgalloc.h>
  17 #include <asm/pgtable.h>
  18
  19 /*
  20  * Permanent SPARSEMEM data:
  21  *
  22  * 1) mem_section       - memory sections, mem_map's for valid memory
  23  */
  24 #ifdef CONFIG_SPARSEMEM_EXTREME
  25 struct mem_section *mem_section[NR_SECTION_ROOTS]
  26         ____cacheline_internodealigned_in_smp;
  27 #else
  28 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
  29         ____cacheline_internodealigned_in_smp;
  30 #endif
  31 EXPORT_SYMBOL(mem_section);
  32
  33 #ifdef NODE_NOT_IN_PAGE_FLAGS
  34 /*
  35  * If we did not store the node number in the page then we have to
  36  * do a lookup in the section_to_node_table in order to find which
  37  * node the page belongs to.
  38  */
  39 #if MAX_NUMNODES <= 256
  40 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
  41 #else
  42 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
  43 #endif
  44
  45 int page_to_nid(const struct page *page)
  46 {
  47         return section_to_node_table[page_to_section(page)];
  48 }
  49 EXPORT_SYMBOL(page_to_nid);
  50
  51 static void set_section_nid(unsigned long section_nr, int nid)
  52 {
  53         section_to_node_table[section_nr] = nid;
  54 }
  55 #else /* !NODE_NOT_IN_PAGE_FLAGS */
  56 static inline void set_section_nid(unsigned long section_nr, int nid)
  57 {
  58 }
  59 #endif
  60
  61 #ifdef CONFIG_SPARSEMEM_EXTREME
  62 static struct mem_section noinline __init_refok *sparse_index_alloc(int nid)
  63 {
  64         struct mem_section *section = NULL;
  65         unsigned long array_size = SECTIONS_PER_ROOT *
  66                                    sizeof(struct mem_section);
  67
  68         if (slab_is_available()) {
  69                 if (node_state(nid, N_HIGH_MEMORY))
  70                         section = kzalloc_node(array_size, GFP_KERNEL, nid);
  71                 else
  72                         section = kzalloc(array_size, GFP_KERNEL);
  73         } else {
  74                 section = memblock_virt_alloc_node(array_size, nid);
  75         }
  76
  77         return section;
  78 }
  79
  80 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
  81 {
  82         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
  83         struct mem_section *section;
  84
  85         if (mem_section[root])
  86                 return -EEXIST;
  87
  88         section = sparse_index_alloc(nid);
  89         if (!section)
  90                 return -ENOMEM;
  91
  92         mem_section[root] = section;
  93
  94         return 0;
  95 }
  96 #else /* !SPARSEMEM_EXTREME */
  97 static inline int sparse_index_init(unsigned long section_nr, int nid)
  98 {
  99         return 0;
 100 }
 101 #endif
 102
 103 /*
 104  * Although written for the SPARSEMEM_EXTREME case, this happens
 105  * to also work for the flat array case because
 106  * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
 107  */
 108 int __section_nr(struct mem_section* ms)
 109 {
 110         unsigned long root_nr;
 111         struct mem_section* root;
 112
 113         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
 114                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
 115                 if (!root)
 116                         continue;
 117
 118                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
 119                      break;
 120         }
 121
 122         VM_BUG_ON(root_nr == NR_SECTION_ROOTS);
 123
 124         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
 125 }
 126
 127 /*
 128  * During early boot, before section_mem_map is used for an actual
 129  * mem_map, we use section_mem_map to store the section's NUMA
 130  * node.  This keeps us from having to use another data structure.  The
 131  * node information is cleared just before we store the real mem_map.
 132  */
 133 static inline unsigned long sparse_encode_early_nid(int nid)
 134 {
 135         return (nid << SECTION_NID_SHIFT);
 136 }
 137
 138 static inline int sparse_early_nid(struct mem_section *section)
 139 {
 140         return (section->section_mem_map >> SECTION_NID_SHIFT);
 141 }
 142
 143 /* Validate the physical addressing limitations of the model */
 144 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
 145                                                 unsigned long *end_pfn)
 146 {
 147         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
 148
 149         /*
 150          * Sanity checks - do not allow an architecture to pass
 151          * in larger pfns than the maximum scope of sparsemem:
 152          */
 153         if (*start_pfn > max_sparsemem_pfn) {
 154                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 155                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 156                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 157                 WARN_ON_ONCE(1);
 158                 *start_pfn = max_sparsemem_pfn;
 159                 *end_pfn = max_sparsemem_pfn;
 160         } else if (*end_pfn > max_sparsemem_pfn) {
 161                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 162                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 163                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 164                 WARN_ON_ONCE(1);
 165                 *end_pfn = max_sparsemem_pfn;
 166         }
 167 }
 168
 169 /* Record a memory area against a node. */
 170 void __init memory_present(int nid, unsigned long start, unsigned long end)
 171 {
 172         unsigned long pfn;
 173
 174         start &= PAGE_SECTION_MASK;
 175         mminit_validate_memmodel_limits(&start, &end);
 176         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
 177                 unsigned long section = pfn_to_section_nr(pfn);
 178                 struct mem_section *ms;
 179
 180                 sparse_index_init(section, nid);
 181                 set_section_nid(section, nid);
 182
 183                 ms = __nr_to_section(section);
 184                 if (!ms->section_mem_map)
 185                         ms->section_mem_map = sparse_encode_early_nid(nid) |
 186                                                         SECTION_MARKED_PRESENT;
 187         }
 188 }
 189
 190 /*
 191  * Only used by the i386 NUMA architecures, but relatively
 192  * generic code.
 193  */
 194 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
 195                                                      unsigned long end_pfn)
 196 {
 197         unsigned long pfn;
 198         unsigned long nr_pages = 0;
 199
 200         mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
 201         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 202                 if (nid != early_pfn_to_nid(pfn))
 203                         continue;
 204
 205                 if (pfn_present(pfn))
 206                         nr_pages += PAGES_PER_SECTION;
 207         }
 208
 209         return nr_pages * sizeof(struct page);
 210 }
 211
 212 /*
 213  * Subtle, we encode the real pfn into the mem_map such that
 214  * the identity pfn - section_mem_map will return the actual
 215  * physical page frame number.
 216  */
 217 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
 218 {
 219         return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
 220 }
 221
 222 /*
 223  * Decode mem_map from the coded memmap
 224  */
 225 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
 226 {
 227         /* mask off the extra low bits of information */
 228         coded_mem_map &= SECTION_MAP_MASK;
 229         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
 230 }
 231
 232 static int __meminit sparse_init_one_section(struct mem_section *ms,
 233                 unsigned long pnum, struct page *mem_map,
 234                 unsigned long *pageblock_bitmap)
 235 {
 236         if (!present_section(ms))
 237                 return -EINVAL;
 238
 239         ms->section_mem_map &= ~SECTION_MAP_MASK;
 240         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
 241                                                         SECTION_HAS_MEM_MAP;
 242         ms->pageblock_flags = pageblock_bitmap;
 243
 244         return 1;
 245 }
 246
 247 unsigned long usemap_size(void)
 248 {
 249         unsigned long size_bytes;
 250         size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
 251         size_bytes = roundup(size_bytes, sizeof(unsigned long));
 252         return size_bytes;
 253 }
 254
 255 #ifdef CONFIG_MEMORY_HOTPLUG
 256 static unsigned long *__kmalloc_section_usemap(void)
 257 {
 258         return kmalloc(usemap_size(), GFP_KERNEL);
 259 }
 260 #endif /* CONFIG_MEMORY_HOTPLUG */
 261
 262 #ifdef CONFIG_MEMORY_HOTREMOVE
 263 static unsigned long * __init
 264 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 265                                          unsigned long size)
 266 {
 267         unsigned long goal, limit;
 268         unsigned long *p;
 269         int nid;
 270         /*
 271          * A page may contain usemaps for other sections preventing the
 272          * page being freed and making a section unremovable while
 273          * other sections referencing the usemap remain active. Similarly,
 274          * a pgdat can prevent a section being removed. If section A
 275          * contains a pgdat and section B contains the usemap, both
 276          * sections become inter-dependent. This allocates usemaps
 277          * from the same section as the pgdat where possible to avoid
 278          * this problem.
 279          */
 280         goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
 281         limit = goal + (1UL << PA_SECTION_SHIFT);
 282         nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
 283 again:
 284         p = memblock_virt_alloc_try_nid_nopanic(size,
 285                                                 SMP_CACHE_BYTES, goal, limit,
 286                                                 nid);
 287         if (!p && limit) {
 288                 limit = 0;
 289                 goto again;
 290         }
 291         return p;
 292 }
 293
 294 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 295 {
 296         unsigned long usemap_snr, pgdat_snr;
 297         static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
 298         static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
 299         struct pglist_data *pgdat = NODE_DATA(nid);
 300         int usemap_nid;
 301
 302         usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
 303         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
 304         if (usemap_snr == pgdat_snr)
 305                 return;
 306
 307         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
 308                 /* skip redundant message */
 309                 return;
 310
 311         old_usemap_snr = usemap_snr;
 312         old_pgdat_snr = pgdat_snr;
 313
 314         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
 315         if (usemap_nid != nid) {
 316                 printk(KERN_INFO
 317                        "node %d must be removed before remove section %ld\n",
 318                        nid, usemap_snr);
 319                 return;
 320         }
 321         /*
 322          * There is a circular dependency.
 323          * Some platforms allow un-removable section because they will just
 324          * gather other removable sections for dynamic partitioning.
 325          * Just notify un-removable section's number here.
 326          */
 327         printk(KERN_INFO "Section %ld and %ld (node %d)", usemap_snr,
 328                pgdat_snr, nid);
 329         printk(KERN_CONT
 330                " have a circular dependency on usemap and pgdat allocations\n");
 331 }
 332 #else
 333 static unsigned long * __init
 334 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 335                                          unsigned long size)
 336 {
 337         return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
 338 }
 339
 340 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 341 {
 342 }
 343 #endif /* CONFIG_MEMORY_HOTREMOVE */
 344
 345 static void __init sparse_early_usemaps_alloc_node(void *data,
 346                                  unsigned long pnum_begin,
 347                                  unsigned long pnum_end,
 348                                  unsigned long usemap_count, int nodeid)
 349 {
 350         void *usemap;
 351         unsigned long pnum;
 352         unsigned long **usemap_map = (unsigned long **)data;
 353         int size = usemap_size();
 354
 355         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
 356                                                           size * usemap_count);
 357         if (!usemap) {
 358                 printk(KERN_WARNING "%s: allocation failed\n", __func__);
 359                 return;
 360         }
 361
 362         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 363                 if (!present_section_nr(pnum))
 364                         continue;
 365                 usemap_map[pnum] = usemap;
 366                 usemap += size;
 367                 check_usemap_section_nr(nodeid, usemap_map[pnum]);
 368         }
 369 }
 370
 371 #ifndef CONFIG_SPARSEMEM_VMEMMAP
 372 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
 373 {
 374         struct page *map;
 375         unsigned long size;
 376
 377         map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
 378         if (map)
 379                 return map;
 380
 381         size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 382         map = memblock_virt_alloc_try_nid(size,
 383                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 384                                           BOOTMEM_ALLOC_ACCESSIBLE, nid);
 385         return map;
 386 }
 387 void __init sparse_mem_maps_populate_node(struct page **map_map,
 388                                           unsigned long pnum_begin,
 389                                           unsigned long pnum_end,
 390                                           unsigned long map_count, int nodeid)
 391 {
 392         void *map;
 393         unsigned long pnum;
 394         unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
 395
 396         map = alloc_remap(nodeid, size * map_count);
 397         if (map) {
 398                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 399                         if (!present_section_nr(pnum))
 400                                 continue;
 401                         map_map[pnum] = map;
 402                         map += size;
 403                 }
 404                 return;
 405         }
 406
 407         size = PAGE_ALIGN(size);
 408         map = memblock_virt_alloc_try_nid(size * map_count,
 409                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 410                                           BOOTMEM_ALLOC_ACCESSIBLE, nodeid);
 411         if (map) {
 412                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 413                         if (!present_section_nr(pnum))
 414                                 continue;
 415                         map_map[pnum] = map;
 416                         map += size;
 417                 }
 418                 return;
 419         }
 420
 421         /* fallback */
 422         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 423                 struct mem_section *ms;
 424
 425                 if (!present_section_nr(pnum))
 426                         continue;
 427                 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
 428                 if (map_map[pnum])
 429                         continue;
 430                 ms = __nr_to_section(pnum);
 431                 printk(KERN_ERR "%s: sparsemem memory map backing failed "
 432                         "some memory will not be available.\n", __func__);
 433                 ms->section_mem_map = 0;
 434         }
 435 }
 436 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 437
 438 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 439 static void __init sparse_early_mem_maps_alloc_node(void *data,
 440                                  unsigned long pnum_begin,
 441                                  unsigned long pnum_end,
 442                                  unsigned long map_count, int nodeid)
 443 {
 444         struct page **map_map = (struct page **)data;
 445         sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
 446                                          map_count, nodeid);
 447 }
 448 #else
 449 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
 450 {
 451         struct page *map;
 452         struct mem_section *ms = __nr_to_section(pnum);
 453         int nid = sparse_early_nid(ms);
 454
 455         map = sparse_mem_map_populate(pnum, nid);
 456         if (map)
 457                 return map;
 458
 459         printk(KERN_ERR "%s: sparsemem memory map backing failed "
 460                         "some memory will not be available.\n", __func__);
 461         ms->section_mem_map = 0;
 462         return NULL;
 463 }
 464 #endif
 465
 466 void __weak __meminit vmemmap_populate_print_last(void)
 467 {
 468 }
 469
 470 /**
 471  *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
 472  *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
 473  */
 474 static void __init alloc_usemap_and_memmap(void (*alloc_func)
 475                                         (void *, unsigned long, unsigned long,
 476                                         unsigned long, int), void *data)
 477 {
 478         unsigned long pnum;
 479         unsigned long map_count;
 480         int nodeid_begin = 0;
 481         unsigned long pnum_begin = 0;
 482
 483         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 484                 struct mem_section *ms;
 485
 486                 if (!present_section_nr(pnum))
 487                         continue;
 488                 ms = __nr_to_section(pnum);
 489                 nodeid_begin = sparse_early_nid(ms);
 490                 pnum_begin = pnum;
 491                 break;
 492         }
 493         map_count = 1;
 494         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
 495                 struct mem_section *ms;
 496                 int nodeid;
 497
 498                 if (!present_section_nr(pnum))
 499                         continue;
 500                 ms = __nr_to_section(pnum);
 501                 nodeid = sparse_early_nid(ms);
 502                 if (nodeid == nodeid_begin) {
 503                         map_count++;
 504                         continue;
 505                 }
 506                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
 507                 alloc_func(data, pnum_begin, pnum,
 508                                                 map_count, nodeid_begin);
 509                 /* new start, update count etc*/
 510                 nodeid_begin = nodeid;
 511                 pnum_begin = pnum;
 512                 map_count = 1;
 513         }
 514         /* ok, last chunk */
 515         alloc_func(data, pnum_begin, NR_MEM_SECTIONS,
 516                                                 map_count, nodeid_begin);
 517 }
 518
 519 /*
 520  * Allocate the accumulated non-linear sections, allocate a mem_map
 521  * for each and record the physical to section mapping.
 522  */
 523 void __init sparse_init(void)
 524 {
 525         unsigned long pnum;
 526         struct page *map;
 527         unsigned long *usemap;
 528         unsigned long **usemap_map;
 529         int size;
 530 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 531         int size2;
 532         struct page **map_map;
 533 #endif
 534
 535         /* see include/linux/mmzone.h 'struct mem_section' definition */
 536         BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
 537
 538         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
 539         set_pageblock_order();
 540
 541         /*
 542          * map is using big page (aka 2M in x86 64 bit)
 543          * usemap is less one page (aka 24 bytes)
 544          * so alloc 2M (with 2M align) and 24 bytes in turn will
 545          * make next 2M slip to one more 2M later.
 546          * then in big system, the memory will have a lot of holes...
 547          * here try to allocate 2M pages continuously.
 548          *
 549          * powerpc need to call sparse_init_one_section right after each
 550          * sparse_early_mem_map_alloc, so allocate usemap_map at first.
 551          */
 552         size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
 553         usemap_map = memblock_virt_alloc(size, 0);
 554         if (!usemap_map)
 555                 panic("can not allocate usemap_map\n");
 556         alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
 557                                                         (void *)usemap_map);
 558
 559 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 560         size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
 561         map_map = memblock_virt_alloc(size2, 0);
 562         if (!map_map)
 563                 panic("can not allocate map_map\n");
 564         alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
 565                                                         (void *)map_map);
 566 #endif
 567
 568         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 569                 if (!present_section_nr(pnum))
 570                         continue;
 571
 572                 usemap = usemap_map[pnum];
 573                 if (!usemap)
 574                         continue;
 575
 576 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 577                 map = map_map[pnum];
 578 #else
 579                 map = sparse_early_mem_map_alloc(pnum);
 580 #endif
 581                 if (!map)
 582                         continue;
 583
 584                 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
 585                                                                 usemap);
 586         }
 587
 588         vmemmap_populate_print_last();
 589
 590 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 591         memblock_free_early(__pa(map_map), size2);
 592 #endif
 593         memblock_free_early(__pa(usemap_map), size);
 594 }
 595
 596 #ifdef CONFIG_MEMORY_HOTPLUG
 597 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 598 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
 599 {
 600         /* This will make the necessary allocations eventually. */
 601         return sparse_mem_map_populate(pnum, nid);
 602 }
 603 static void __kfree_section_memmap(struct page *memmap)
 604 {
 605         unsigned long start = (unsigned long)memmap;
 606         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 607
 608         vmemmap_free(start, end);
 609 }
 610 #ifdef CONFIG_MEMORY_HOTREMOVE
 611 static void free_map_bootmem(struct page *memmap)
 612 {
 613         unsigned long start = (unsigned long)memmap;
 614         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 615
 616         vmemmap_free(start, end);
 617 }
 618 #endif /* CONFIG_MEMORY_HOTREMOVE */
 619 #else
 620 static struct page *__kmalloc_section_memmap(void)
 621 {
 622         struct page *page, *ret;
 623         unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
 624
 625         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 626         if (page)
 627                 goto got_map_page;
 628
 629         ret = vmalloc(memmap_size);
 630         if (ret)
 631                 goto got_map_ptr;
 632
 633         return NULL;
 634 got_map_page:
 635         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
 636 got_map_ptr:
 637
 638         return ret;
 639 }
 640
 641 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
 642 {
 643         return __kmalloc_section_memmap();
 644 }
 645
 646 static void __kfree_section_memmap(struct page *memmap)
 647 {
 648         if (is_vmalloc_addr(memmap))
 649                 vfree(memmap);
 650         else
 651                 free_pages((unsigned long)memmap,
 652                            get_order(sizeof(struct page) * PAGES_PER_SECTION));
 653 }
 654
 655 #ifdef CONFIG_MEMORY_HOTREMOVE
 656 static void free_map_bootmem(struct page *memmap)
 657 {
 658         unsigned long maps_section_nr, removing_section_nr, i;
 659         unsigned long magic, nr_pages;
 660         struct page *page = virt_to_page(memmap);
 661
 662         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 663                 >> PAGE_SHIFT;
 664
 665         for (i = 0; i < nr_pages; i++, page++) {
 666                 magic = (unsigned long) page->lru.next;
 667
 668                 BUG_ON(magic == NODE_INFO);
 669
 670                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
 671                 removing_section_nr = page->private;
 672
 673                 /*
 674                  * When this function is called, the removing section is
 675                  * logical offlined state. This means all pages are isolated
 676                  * from page allocator. If removing section's memmap is placed
 677                  * on the same section, it must not be freed.
 678                  * If it is freed, page allocator may allocate it which will
 679                  * be removed physically soon.
 680                  */
 681                 if (maps_section_nr != removing_section_nr)
 682                         put_page_bootmem(page);
 683         }
 684 }
 685 #endif /* CONFIG_MEMORY_HOTREMOVE */
 686 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 687
 688 /*
 689  * returns the number of sections whose mem_maps were properly
 690  * set.  If this is <=0, then that means that the passed-in
 691  * map was not consumed and must be freed.
 692  */
 693 int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 694 {
 695         unsigned long section_nr = pfn_to_section_nr(start_pfn);
 696         struct pglist_data *pgdat = zone->zone_pgdat;
 697         struct mem_section *ms;
 698         struct page *memmap;
 699         unsigned long *usemap;
 700         unsigned long flags;
 701         int ret;
 702
 703         /*
 704          * no locking for this, because it does its own
 705          * plus, it does a kmalloc
 706          */
 707         ret = sparse_index_init(section_nr, pgdat->node_id);
 708         if (ret < 0 && ret != -EEXIST)
 709                 return ret;
 710         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id);
 711         if (!memmap)
 712                 return -ENOMEM;
 713         usemap = __kmalloc_section_usemap();
 714         if (!usemap) {
 715                 __kfree_section_memmap(memmap);
 716                 return -ENOMEM;
 717         }
 718
 719         pgdat_resize_lock(pgdat, &flags);
 720
 721         ms = __pfn_to_section(start_pfn);
 722         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
 723                 ret = -EEXIST;
 724                 goto out;
 725         }
 726
 727         memset(memmap, 0, sizeof(struct page) * PAGES_PER_SECTION);
 728
 729         ms->section_mem_map |= SECTION_MARKED_PRESENT;
 730
 731         ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
 732
 733 out:
 734         pgdat_resize_unlock(pgdat, &flags);
 735         if (ret <= 0) {
 736                 kfree(usemap);
 737                 __kfree_section_memmap(memmap);
 738         }
 739         return ret;
 740 }
 741
 742 #ifdef CONFIG_MEMORY_HOTREMOVE
 743 #ifdef CONFIG_MEMORY_FAILURE
 744 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 745 {
 746         int i;
 747
 748         if (!memmap)
 749                 return;
 750
 751         for (i = 0; i < PAGES_PER_SECTION; i++) {
 752                 if (PageHWPoison(&memmap[i])) {
 753                         atomic_long_sub(1, &num_poisoned_pages);
 754                         ClearPageHWPoison(&memmap[i]);
 755                 }
 756         }
 757 }
 758 #else
 759 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 760 {
 761 }
 762 #endif
 763
 764 static void free_section_usemap(struct page *memmap, unsigned long *usemap)
 765 {
 766         struct page *usemap_page;
 767
 768         if (!usemap)
 769                 return;
 770
 771         usemap_page = virt_to_page(usemap);
 772         /*
 773          * Check to see if allocation came from hot-plug-add
 774          */
 775         if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
 776                 kfree(usemap);
 777                 if (memmap)
 778                         __kfree_section_memmap(memmap);
 779                 return;
 780         }
 781
 782         /*
 783          * The usemap came from bootmem. This is packed with other usemaps
 784          * on the section which has pgdat at boot time. Just keep it as is now.
 785          */
 786
 787         if (memmap)
 788                 free_map_bootmem(memmap);
 789 }
 790
 791 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
 792 {
 793         struct page *memmap = NULL;
 794         unsigned long *usemap = NULL, flags;
 795         struct pglist_data *pgdat = zone->zone_pgdat;
 796
 797         pgdat_resize_lock(pgdat, &flags);
 798         if (ms->section_mem_map) {
 799                 usemap = ms->pageblock_flags;
 800                 memmap = sparse_decode_mem_map(ms->section_mem_map,
 801                                                 __section_nr(ms));
 802                 ms->section_mem_map = 0;
 803                 ms->pageblock_flags = NULL;
 804         }
 805         pgdat_resize_unlock(pgdat, &flags);
 806
 807         clear_hwpoisoned_pages(memmap, PAGES_PER_SECTION);
 808         free_section_usemap(memmap, usemap);
 809 }
 810 #endif /* CONFIG_MEMORY_HOTREMOVE */
 811 #endif /* CONFIG_MEMORY_HOTPLUG */