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