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                 pr_info("node %d must be removed before remove section %ld\n",
 317                         nid, usemap_snr);
 318                 return;
 319         }
 320         /*
 321          * There is a circular dependency.
 322          * Some platforms allow un-removable section because they will just
 323          * gather other removable sections for dynamic partitioning.
 324          * Just notify un-removable section's number here.
 325          */
 326         pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n",
 327                 usemap_snr, pgdat_snr, nid);
 328 }
 329 #else
 330 static unsigned long * __init
 331 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 332                                          unsigned long size)
 333 {
 334         return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
 335 }
 336
 337 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 338 {
 339 }
 340 #endif /* CONFIG_MEMORY_HOTREMOVE */
 341
 342 static void __init sparse_early_usemaps_alloc_node(void *data,
 343                                  unsigned long pnum_begin,
 344                                  unsigned long pnum_end,
 345                                  unsigned long usemap_count, int nodeid)
 346 {
 347         void *usemap;
 348         unsigned long pnum;
 349         unsigned long **usemap_map = (unsigned long **)data;
 350         int size = usemap_size();
 351
 352         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
 353                                                           size * usemap_count);
 354         if (!usemap) {
 355                 pr_warn("%s: allocation failed\n", __func__);
 356                 return;
 357         }
 358
 359         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 360                 if (!present_section_nr(pnum))
 361                         continue;
 362                 usemap_map[pnum] = usemap;
 363                 usemap += size;
 364                 check_usemap_section_nr(nodeid, usemap_map[pnum]);
 365         }
 366 }
 367
 368 #ifndef CONFIG_SPARSEMEM_VMEMMAP
 369 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
 370 {
 371         struct page *map;
 372         unsigned long size;
 373
 374         map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
 375         if (map)
 376                 return map;
 377
 378         size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 379         map = memblock_virt_alloc_try_nid(size,
 380                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 381                                           BOOTMEM_ALLOC_ACCESSIBLE, nid);
 382         return map;
 383 }
 384 void __init sparse_mem_maps_populate_node(struct page **map_map,
 385                                           unsigned long pnum_begin,
 386                                           unsigned long pnum_end,
 387                                           unsigned long map_count, int nodeid)
 388 {
 389         void *map;
 390         unsigned long pnum;
 391         unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
 392
 393         map = alloc_remap(nodeid, size * map_count);
 394         if (map) {
 395                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 396                         if (!present_section_nr(pnum))
 397                                 continue;
 398                         map_map[pnum] = map;
 399                         map += size;
 400                 }
 401                 return;
 402         }
 403
 404         size = PAGE_ALIGN(size);
 405         map = memblock_virt_alloc_try_nid(size * map_count,
 406                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 407                                           BOOTMEM_ALLOC_ACCESSIBLE, nodeid);
 408         if (map) {
 409                 for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 410                         if (!present_section_nr(pnum))
 411                                 continue;
 412                         map_map[pnum] = map;
 413                         map += size;
 414                 }
 415                 return;
 416         }
 417
 418         /* fallback */
 419         for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 420                 struct mem_section *ms;
 421
 422                 if (!present_section_nr(pnum))
 423                         continue;
 424                 map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
 425                 if (map_map[pnum])
 426                         continue;
 427                 ms = __nr_to_section(pnum);
 428                 pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
 429                        __func__);
 430                 ms->section_mem_map = 0;
 431         }
 432 }
 433 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 434
 435 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 436 static void __init sparse_early_mem_maps_alloc_node(void *data,
 437                                  unsigned long pnum_begin,
 438                                  unsigned long pnum_end,
 439                                  unsigned long map_count, int nodeid)
 440 {
 441         struct page **map_map = (struct page **)data;
 442         sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
 443                                          map_count, nodeid);
 444 }
 445 #else
 446 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
 447 {
 448         struct page *map;
 449         struct mem_section *ms = __nr_to_section(pnum);
 450         int nid = sparse_early_nid(ms);
 451
 452         map = sparse_mem_map_populate(pnum, nid);
 453         if (map)
 454                 return map;
 455
 456         pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
 457                __func__);
 458         ms->section_mem_map = 0;
 459         return NULL;
 460 }
 461 #endif
 462
 463 void __weak __meminit vmemmap_populate_print_last(void)
 464 {
 465 }
 466
 467 /**
 468  *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
 469  *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
 470  */
 471 static void __init alloc_usemap_and_memmap(void (*alloc_func)
 472                                         (void *, unsigned long, unsigned long,
 473                                         unsigned long, int), void *data)
 474 {
 475         unsigned long pnum;
 476         unsigned long map_count;
 477         int nodeid_begin = 0;
 478         unsigned long pnum_begin = 0;
 479
 480         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 481                 struct mem_section *ms;
 482
 483                 if (!present_section_nr(pnum))
 484                         continue;
 485                 ms = __nr_to_section(pnum);
 486                 nodeid_begin = sparse_early_nid(ms);
 487                 pnum_begin = pnum;
 488                 break;
 489         }
 490         map_count = 1;
 491         for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
 492                 struct mem_section *ms;
 493                 int nodeid;
 494
 495                 if (!present_section_nr(pnum))
 496                         continue;
 497                 ms = __nr_to_section(pnum);
 498                 nodeid = sparse_early_nid(ms);
 499                 if (nodeid == nodeid_begin) {
 500                         map_count++;
 501                         continue;
 502                 }
 503                 /* ok, we need to take cake of from pnum_begin to pnum - 1*/
 504                 alloc_func(data, pnum_begin, pnum,
 505                                                 map_count, nodeid_begin);
 506                 /* new start, update count etc*/
 507                 nodeid_begin = nodeid;
 508                 pnum_begin = pnum;
 509                 map_count = 1;
 510         }
 511         /* ok, last chunk */
 512         alloc_func(data, pnum_begin, NR_MEM_SECTIONS,
 513                                                 map_count, nodeid_begin);
 514 }
 515
 516 /*
 517  * Allocate the accumulated non-linear sections, allocate a mem_map
 518  * for each and record the physical to section mapping.
 519  */
 520 void __init sparse_init(void)
 521 {
 522         unsigned long pnum;
 523         struct page *map;
 524         unsigned long *usemap;
 525         unsigned long **usemap_map;
 526         int size;
 527 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 528         int size2;
 529         struct page **map_map;
 530 #endif
 531
 532         /* see include/linux/mmzone.h 'struct mem_section' definition */
 533         BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
 534
 535         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
 536         set_pageblock_order();
 537
 538         /*
 539          * map is using big page (aka 2M in x86 64 bit)
 540          * usemap is less one page (aka 24 bytes)
 541          * so alloc 2M (with 2M align) and 24 bytes in turn will
 542          * make next 2M slip to one more 2M later.
 543          * then in big system, the memory will have a lot of holes...
 544          * here try to allocate 2M pages continuously.
 545          *
 546          * powerpc need to call sparse_init_one_section right after each
 547          * sparse_early_mem_map_alloc, so allocate usemap_map at first.
 548          */
 549         size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
 550         usemap_map = memblock_virt_alloc(size, 0);
 551         if (!usemap_map)
 552                 panic("can not allocate usemap_map\n");
 553         alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
 554                                                         (void *)usemap_map);
 555
 556 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 557         size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
 558         map_map = memblock_virt_alloc(size2, 0);
 559         if (!map_map)
 560                 panic("can not allocate map_map\n");
 561         alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
 562                                                         (void *)map_map);
 563 #endif
 564
 565         for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 566                 if (!present_section_nr(pnum))
 567                         continue;
 568
 569                 usemap = usemap_map[pnum];
 570                 if (!usemap)
 571                         continue;
 572
 573 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 574                 map = map_map[pnum];
 575 #else
 576                 map = sparse_early_mem_map_alloc(pnum);
 577 #endif
 578                 if (!map)
 579                         continue;
 580
 581                 sparse_init_one_section(__nr_to_section(pnum), pnum, map,
 582                                                                 usemap);
 583         }
 584
 585         vmemmap_populate_print_last();
 586
 587 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 588         memblock_free_early(__pa(map_map), size2);
 589 #endif
 590         memblock_free_early(__pa(usemap_map), size);
 591 }
 592
 593 #ifdef CONFIG_MEMORY_HOTPLUG
 594 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 595 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
 596 {
 597         /* This will make the necessary allocations eventually. */
 598         return sparse_mem_map_populate(pnum, nid);
 599 }
 600 static void __kfree_section_memmap(struct page *memmap)
 601 {
 602         unsigned long start = (unsigned long)memmap;
 603         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 604
 605         vmemmap_free(start, end);
 606 }
 607 #ifdef CONFIG_MEMORY_HOTREMOVE
 608 static void free_map_bootmem(struct page *memmap)
 609 {
 610         unsigned long start = (unsigned long)memmap;
 611         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 612
 613         vmemmap_free(start, end);
 614 }
 615 #endif /* CONFIG_MEMORY_HOTREMOVE */
 616 #else
 617 static struct page *__kmalloc_section_memmap(void)
 618 {
 619         struct page *page, *ret;
 620         unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
 621
 622         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 623         if (page)
 624                 goto got_map_page;
 625
 626         ret = vmalloc(memmap_size);
 627         if (ret)
 628                 goto got_map_ptr;
 629
 630         return NULL;
 631 got_map_page:
 632         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
 633 got_map_ptr:
 634
 635         return ret;
 636 }
 637
 638 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
 639 {
 640         return __kmalloc_section_memmap();
 641 }
 642
 643 static void __kfree_section_memmap(struct page *memmap)
 644 {
 645         if (is_vmalloc_addr(memmap))
 646                 vfree(memmap);
 647         else
 648                 free_pages((unsigned long)memmap,
 649                            get_order(sizeof(struct page) * PAGES_PER_SECTION));
 650 }
 651
 652 #ifdef CONFIG_MEMORY_HOTREMOVE
 653 static void free_map_bootmem(struct page *memmap)
 654 {
 655         unsigned long maps_section_nr, removing_section_nr, i;
 656         unsigned long magic, nr_pages;
 657         struct page *page = virt_to_page(memmap);
 658
 659         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 660                 >> PAGE_SHIFT;
 661
 662         for (i = 0; i < nr_pages; i++, page++) {
 663                 magic = (unsigned long) page->lru.next;
 664
 665                 BUG_ON(magic == NODE_INFO);
 666
 667                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
 668                 removing_section_nr = page->private;
 669
 670                 /*
 671                  * When this function is called, the removing section is
 672                  * logical offlined state. This means all pages are isolated
 673                  * from page allocator. If removing section's memmap is placed
 674                  * on the same section, it must not be freed.
 675                  * If it is freed, page allocator may allocate it which will
 676                  * be removed physically soon.
 677                  */
 678                 if (maps_section_nr != removing_section_nr)
 679                         put_page_bootmem(page);
 680         }
 681 }
 682 #endif /* CONFIG_MEMORY_HOTREMOVE */
 683 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 684
 685 /*
 686  * returns the number of sections whose mem_maps were properly
 687  * set.  If this is <=0, then that means that the passed-in
 688  * map was not consumed and must be freed.
 689  */
 690 int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn)
 691 {
 692         unsigned long section_nr = pfn_to_section_nr(start_pfn);
 693         struct pglist_data *pgdat = zone->zone_pgdat;
 694         struct mem_section *ms;
 695         struct page *memmap;
 696         unsigned long *usemap;
 697         unsigned long flags;
 698         int ret;
 699
 700         /*
 701          * no locking for this, because it does its own
 702          * plus, it does a kmalloc
 703          */
 704         ret = sparse_index_init(section_nr, pgdat->node_id);
 705         if (ret < 0 && ret != -EEXIST)
 706                 return ret;
 707         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id);
 708         if (!memmap)
 709                 return -ENOMEM;
 710         usemap = __kmalloc_section_usemap();
 711         if (!usemap) {
 712                 __kfree_section_memmap(memmap);
 713                 return -ENOMEM;
 714         }
 715
 716         pgdat_resize_lock(pgdat, &flags);
 717
 718         ms = __pfn_to_section(start_pfn);
 719         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
 720                 ret = -EEXIST;
 721                 goto out;
 722         }
 723
 724         memset(memmap, 0, sizeof(struct page) * PAGES_PER_SECTION);
 725
 726         ms->section_mem_map |= SECTION_MARKED_PRESENT;
 727
 728         ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
 729
 730 out:
 731         pgdat_resize_unlock(pgdat, &flags);
 732         if (ret <= 0) {
 733                 kfree(usemap);
 734                 __kfree_section_memmap(memmap);
 735         }
 736         return ret;
 737 }
 738
 739 #ifdef CONFIG_MEMORY_HOTREMOVE
 740 #ifdef CONFIG_MEMORY_FAILURE
 741 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 742 {
 743         int i;
 744
 745         if (!memmap)
 746                 return;
 747
 748         for (i = 0; i < nr_pages; i++) {
 749                 if (PageHWPoison(&memmap[i])) {
 750                         atomic_long_sub(1, &num_poisoned_pages);
 751                         ClearPageHWPoison(&memmap[i]);
 752                 }
 753         }
 754 }
 755 #else
 756 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 757 {
 758 }
 759 #endif
 760
 761 static void free_section_usemap(struct page *memmap, unsigned long *usemap)
 762 {
 763         struct page *usemap_page;
 764
 765         if (!usemap)
 766                 return;
 767
 768         usemap_page = virt_to_page(usemap);
 769         /*
 770          * Check to see if allocation came from hot-plug-add
 771          */
 772         if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
 773                 kfree(usemap);
 774                 if (memmap)
 775                         __kfree_section_memmap(memmap);
 776                 return;
 777         }
 778
 779         /*
 780          * The usemap came from bootmem. This is packed with other usemaps
 781          * on the section which has pgdat at boot time. Just keep it as is now.
 782          */
 783
 784         if (memmap)
 785                 free_map_bootmem(memmap);
 786 }
 787
 788 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
 789                 unsigned long map_offset)
 790 {
 791         struct page *memmap = NULL;
 792         unsigned long *usemap = NULL, flags;
 793         struct pglist_data *pgdat = zone->zone_pgdat;
 794
 795         pgdat_resize_lock(pgdat, &flags);
 796         if (ms->section_mem_map) {
 797                 usemap = ms->pageblock_flags;
 798                 memmap = sparse_decode_mem_map(ms->section_mem_map,
 799                                                 __section_nr(ms));
 800                 ms->section_mem_map = 0;
 801                 ms->pageblock_flags = NULL;
 802         }
 803         pgdat_resize_unlock(pgdat, &flags);
 804
 805         clear_hwpoisoned_pages(memmap + map_offset,
 806                         PAGES_PER_SECTION - map_offset);
 807         free_section_usemap(memmap, usemap);
 808 }
 809 #endif /* CONFIG_MEMORY_HOTREMOVE */
 810 #endif /* CONFIG_MEMORY_HOTPLUG */