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