mm/sparse.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * sparse memory mappings.
   4  */
   5 #include <linux/mm.h>
   6 #include <linux/slab.h>
   7 #include <linux/mmzone.h>
   8 #include <linux/bootmem.h>
   9 #include <linux/compiler.h>
  10 #include <linux/highmem.h>
  11 #include <linux/export.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/vmalloc.h>
  14
  15 #include "internal.h"
  16 #include <asm/dma.h>
  17 #include <asm/pgalloc.h>
  18 #include <asm/pgtable.h>
  19
  20 /*
  21  * Permanent SPARSEMEM data:
  22  *
  23  * 1) mem_section       - memory sections, mem_map's for valid memory
  24  */
  25 #ifdef CONFIG_SPARSEMEM_EXTREME
  26 struct mem_section **mem_section;
  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 noinline struct mem_section __ref *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                 section = kzalloc_node(array_size, GFP_KERNEL, nid);
  70         else
  71                 section = memblock_virt_alloc_node(array_size, nid);
  72
  73         return section;
  74 }
  75
  76 static int __meminit sparse_index_init(unsigned long section_nr, int nid)
  77 {
  78         unsigned long root = SECTION_NR_TO_ROOT(section_nr);
  79         struct mem_section *section;
  80
  81         if (mem_section[root])
  82                 return -EEXIST;
  83
  84         section = sparse_index_alloc(nid);
  85         if (!section)
  86                 return -ENOMEM;
  87
  88         mem_section[root] = section;
  89
  90         return 0;
  91 }
  92 #else /* !SPARSEMEM_EXTREME */
  93 static inline int sparse_index_init(unsigned long section_nr, int nid)
  94 {
  95         return 0;
  96 }
  97 #endif
  98
  99 #ifdef CONFIG_SPARSEMEM_EXTREME
 100 int __section_nr(struct mem_section* ms)
 101 {
 102         unsigned long root_nr;
 103         struct mem_section *root = NULL;
 104
 105         for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
 106                 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
 107                 if (!root)
 108                         continue;
 109
 110                 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
 111                      break;
 112         }
 113
 114         VM_BUG_ON(!root);
 115
 116         return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
 117 }
 118 #else
 119 int __section_nr(struct mem_section* ms)
 120 {
 121         return (int)(ms - mem_section[0]);
 122 }
 123 #endif
 124
 125 /*
 126  * During early boot, before section_mem_map is used for an actual
 127  * mem_map, we use section_mem_map to store the section's NUMA
 128  * node.  This keeps us from having to use another data structure.  The
 129  * node information is cleared just before we store the real mem_map.
 130  */
 131 static inline unsigned long sparse_encode_early_nid(int nid)
 132 {
 133         return (nid << SECTION_NID_SHIFT);
 134 }
 135
 136 static inline int sparse_early_nid(struct mem_section *section)
 137 {
 138         return (section->section_mem_map >> SECTION_NID_SHIFT);
 139 }
 140
 141 /* Validate the physical addressing limitations of the model */
 142 void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
 143                                                 unsigned long *end_pfn)
 144 {
 145         unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
 146
 147         /*
 148          * Sanity checks - do not allow an architecture to pass
 149          * in larger pfns than the maximum scope of sparsemem:
 150          */
 151         if (*start_pfn > max_sparsemem_pfn) {
 152                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 153                         "Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 154                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 155                 WARN_ON_ONCE(1);
 156                 *start_pfn = max_sparsemem_pfn;
 157                 *end_pfn = max_sparsemem_pfn;
 158         } else if (*end_pfn > max_sparsemem_pfn) {
 159                 mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
 160                         "End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
 161                         *start_pfn, *end_pfn, max_sparsemem_pfn);
 162                 WARN_ON_ONCE(1);
 163                 *end_pfn = max_sparsemem_pfn;
 164         }
 165 }
 166
 167 /*
 168  * There are a number of times that we loop over NR_MEM_SECTIONS,
 169  * looking for section_present() on each.  But, when we have very
 170  * large physical address spaces, NR_MEM_SECTIONS can also be
 171  * very large which makes the loops quite long.
 172  *
 173  * Keeping track of this gives us an easy way to break out of
 174  * those loops early.
 175  */
 176 int __highest_present_section_nr;
 177 static void section_mark_present(struct mem_section *ms)
 178 {
 179         int section_nr = __section_nr(ms);
 180
 181         if (section_nr > __highest_present_section_nr)
 182                 __highest_present_section_nr = section_nr;
 183
 184         ms->section_mem_map |= SECTION_MARKED_PRESENT;
 185 }
 186
 187 static inline int next_present_section_nr(int section_nr)
 188 {
 189         do {
 190                 section_nr++;
 191                 if (present_section_nr(section_nr))
 192                         return section_nr;
 193         } while ((section_nr <= __highest_present_section_nr));
 194
 195         return -1;
 196 }
 197 #define for_each_present_section_nr(start, section_nr)          \
 198         for (section_nr = next_present_section_nr(start-1);     \
 199              ((section_nr >= 0) &&                              \
 200               (section_nr <= __highest_present_section_nr));    \
 201              section_nr = next_present_section_nr(section_nr))
 202
 203 static inline unsigned long first_present_section_nr(void)
 204 {
 205         return next_present_section_nr(-1);
 206 }
 207
 208 /* Record a memory area against a node. */
 209 void __init memory_present(int nid, unsigned long start, unsigned long end)
 210 {
 211         unsigned long pfn;
 212
 213 #ifdef CONFIG_SPARSEMEM_EXTREME
 214         if (unlikely(!mem_section)) {
 215                 unsigned long size, align;
 216
 217                 size = sizeof(struct mem_section*) * NR_SECTION_ROOTS;
 218                 align = 1 << (INTERNODE_CACHE_SHIFT);
 219                 mem_section = memblock_virt_alloc(size, align);
 220         }
 221 #endif
 222
 223         start &= PAGE_SECTION_MASK;
 224         mminit_validate_memmodel_limits(&start, &end);
 225         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
 226                 unsigned long section = pfn_to_section_nr(pfn);
 227                 struct mem_section *ms;
 228
 229                 sparse_index_init(section, nid);
 230                 set_section_nid(section, nid);
 231
 232                 ms = __nr_to_section(section);
 233                 if (!ms->section_mem_map) {
 234                         ms->section_mem_map = sparse_encode_early_nid(nid) |
 235                                                         SECTION_IS_ONLINE;
 236                         section_mark_present(ms);
 237                 }
 238         }
 239 }
 240
 241 /*
 242  * Subtle, we encode the real pfn into the mem_map such that
 243  * the identity pfn - section_mem_map will return the actual
 244  * physical page frame number.
 245  */
 246 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
 247 {
 248         unsigned long coded_mem_map =
 249                 (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
 250         BUILD_BUG_ON(SECTION_MAP_LAST_BIT > (1UL<<PFN_SECTION_SHIFT));
 251         BUG_ON(coded_mem_map & ~SECTION_MAP_MASK);
 252         return coded_mem_map;
 253 }
 254
 255 /*
 256  * Decode mem_map from the coded memmap
 257  */
 258 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
 259 {
 260         /* mask off the extra low bits of information */
 261         coded_mem_map &= SECTION_MAP_MASK;
 262         return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
 263 }
 264
 265 static void __meminit sparse_init_one_section(struct mem_section *ms,
 266                 unsigned long pnum, struct page *mem_map,
 267                 unsigned long *pageblock_bitmap)
 268 {
 269         ms->section_mem_map &= ~SECTION_MAP_MASK;
 270         ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
 271                                                         SECTION_HAS_MEM_MAP;
 272         ms->pageblock_flags = pageblock_bitmap;
 273 }
 274
 275 unsigned long usemap_size(void)
 276 {
 277         return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
 278 }
 279
 280 #ifdef CONFIG_MEMORY_HOTPLUG
 281 static unsigned long *__kmalloc_section_usemap(void)
 282 {
 283         return kmalloc(usemap_size(), GFP_KERNEL);
 284 }
 285 #endif /* CONFIG_MEMORY_HOTPLUG */
 286
 287 #ifdef CONFIG_MEMORY_HOTREMOVE
 288 static unsigned long * __init
 289 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 290                                          unsigned long size)
 291 {
 292         unsigned long goal, limit;
 293         unsigned long *p;
 294         int nid;
 295         /*
 296          * A page may contain usemaps for other sections preventing the
 297          * page being freed and making a section unremovable while
 298          * other sections referencing the usemap remain active. Similarly,
 299          * a pgdat can prevent a section being removed. If section A
 300          * contains a pgdat and section B contains the usemap, both
 301          * sections become inter-dependent. This allocates usemaps
 302          * from the same section as the pgdat where possible to avoid
 303          * this problem.
 304          */
 305         goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
 306         limit = goal + (1UL << PA_SECTION_SHIFT);
 307         nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
 308 again:
 309         p = memblock_virt_alloc_try_nid_nopanic(size,
 310                                                 SMP_CACHE_BYTES, goal, limit,
 311                                                 nid);
 312         if (!p && limit) {
 313                 limit = 0;
 314                 goto again;
 315         }
 316         return p;
 317 }
 318
 319 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 320 {
 321         unsigned long usemap_snr, pgdat_snr;
 322         static unsigned long old_usemap_snr;
 323         static unsigned long old_pgdat_snr;
 324         struct pglist_data *pgdat = NODE_DATA(nid);
 325         int usemap_nid;
 326
 327         /* First call */
 328         if (!old_usemap_snr) {
 329                 old_usemap_snr = NR_MEM_SECTIONS;
 330                 old_pgdat_snr = NR_MEM_SECTIONS;
 331         }
 332
 333         usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
 334         pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
 335         if (usemap_snr == pgdat_snr)
 336                 return;
 337
 338         if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
 339                 /* skip redundant message */
 340                 return;
 341
 342         old_usemap_snr = usemap_snr;
 343         old_pgdat_snr = pgdat_snr;
 344
 345         usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
 346         if (usemap_nid != nid) {
 347                 pr_info("node %d must be removed before remove section %ld\n",
 348                         nid, usemap_snr);
 349                 return;
 350         }
 351         /*
 352          * There is a circular dependency.
 353          * Some platforms allow un-removable section because they will just
 354          * gather other removable sections for dynamic partitioning.
 355          * Just notify un-removable section's number here.
 356          */
 357         pr_info("Section %ld and %ld (node %d) have a circular dependency on usemap and pgdat allocations\n",
 358                 usemap_snr, pgdat_snr, nid);
 359 }
 360 #else
 361 static unsigned long * __init
 362 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 363                                          unsigned long size)
 364 {
 365         return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
 366 }
 367
 368 static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 369 {
 370 }
 371 #endif /* CONFIG_MEMORY_HOTREMOVE */
 372
 373 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 374 static unsigned long __init section_map_size(void)
 375 {
 376         return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE);
 377 }
 378
 379 #else
 380 static unsigned long __init section_map_size(void)
 381 {
 382         return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 383 }
 384
 385 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid,
 386                 struct vmem_altmap *altmap)
 387 {
 388         unsigned long size = section_map_size();
 389         struct page *map = sparse_buffer_alloc(size);
 390
 391         if (map)
 392                 return map;
 393
 394         map = memblock_virt_alloc_try_nid(size,
 395                                           PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
 396                                           BOOTMEM_ALLOC_ACCESSIBLE, nid);
 397         return map;
 398 }
 399 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 400
 401 static void *sparsemap_buf __meminitdata;
 402 static void *sparsemap_buf_end __meminitdata;
 403
 404 static void __init sparse_buffer_init(unsigned long size, int nid)
 405 {
 406         WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */
 407         sparsemap_buf =
 408                 memblock_virt_alloc_try_nid_raw(size, PAGE_SIZE,
 409                                                 __pa(MAX_DMA_ADDRESS),
 410                                                 BOOTMEM_ALLOC_ACCESSIBLE, nid);
 411         sparsemap_buf_end = sparsemap_buf + size;
 412 }
 413
 414 static void __init sparse_buffer_fini(void)
 415 {
 416         unsigned long size = sparsemap_buf_end - sparsemap_buf;
 417
 418         if (sparsemap_buf && size > 0)
 419                 memblock_free_early(__pa(sparsemap_buf), size);
 420         sparsemap_buf = NULL;
 421 }
 422
 423 void * __meminit sparse_buffer_alloc(unsigned long size)
 424 {
 425         void *ptr = NULL;
 426
 427         if (sparsemap_buf) {
 428                 ptr = PTR_ALIGN(sparsemap_buf, size);
 429                 if (ptr + size > sparsemap_buf_end)
 430                         ptr = NULL;
 431                 else
 432                         sparsemap_buf = ptr + size;
 433         }
 434         return ptr;
 435 }
 436
 437 void __weak __meminit vmemmap_populate_print_last(void)
 438 {
 439 }
 440
 441 /*
 442  * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end)
 443  * And number of present sections in this node is map_count.
 444  */
 445 static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 446                                    unsigned long pnum_end,
 447                                    unsigned long map_count)
 448 {
 449         unsigned long pnum, usemap_longs, *usemap;
 450         struct page *map;
 451
 452         usemap_longs = BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS);
 453         usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid),
 454                                                           usemap_size() *
 455                                                           map_count);
 456         if (!usemap) {
 457                 pr_err("%s: node[%d] usemap allocation failed", __func__, nid);
 458                 goto failed;
 459         }
 460         sparse_buffer_init(map_count * section_map_size(), nid);
 461         for_each_present_section_nr(pnum_begin, pnum) {
 462                 if (pnum >= pnum_end)
 463                         break;
 464
 465                 map = sparse_mem_map_populate(pnum, nid, NULL);
 466                 if (!map) {
 467                         pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.",
 468                                __func__, nid);
 469                         pnum_begin = pnum;
 470                         goto failed;
 471                 }
 472                 check_usemap_section_nr(nid, usemap);
 473                 sparse_init_one_section(__nr_to_section(pnum), pnum, map, usemap);
 474                 usemap += usemap_longs;
 475         }
 476         sparse_buffer_fini();
 477         return;
 478 failed:
 479         /* We failed to allocate, mark all the following pnums as not present */
 480         for_each_present_section_nr(pnum_begin, pnum) {
 481                 struct mem_section *ms;
 482
 483                 if (pnum >= pnum_end)
 484                         break;
 485                 ms = __nr_to_section(pnum);
 486                 ms->section_mem_map = 0;
 487         }
 488 }
 489
 490 /*
 491  * Allocate the accumulated non-linear sections, allocate a mem_map
 492  * for each and record the physical to section mapping.
 493  */
 494 void __init sparse_init(void)
 495 {
 496         unsigned long pnum_begin = first_present_section_nr();
 497         int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
 498         unsigned long pnum_end, map_count = 1;
 499
 500         /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
 501         set_pageblock_order();
 502
 503         for_each_present_section_nr(pnum_begin + 1, pnum_end) {
 504                 int nid = sparse_early_nid(__nr_to_section(pnum_end));
 505
 506                 if (nid == nid_begin) {
 507                         map_count++;
 508                         continue;
 509                 }
 510                 /* Init node with sections in range [pnum_begin, pnum_end) */
 511                 sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
 512                 nid_begin = nid;
 513                 pnum_begin = pnum_end;
 514                 map_count = 1;
 515         }
 516         /* cover the last node */
 517         sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
 518         vmemmap_populate_print_last();
 519 }
 520
 521 #ifdef CONFIG_MEMORY_HOTPLUG
 522
 523 /* Mark all memory sections within the pfn range as online */
 524 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 525 {
 526         unsigned long pfn;
 527
 528         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 529                 unsigned long section_nr = pfn_to_section_nr(pfn);
 530                 struct mem_section *ms;
 531
 532                 /* onlining code should never touch invalid ranges */
 533                 if (WARN_ON(!valid_section_nr(section_nr)))
 534                         continue;
 535
 536                 ms = __nr_to_section(section_nr);
 537                 ms->section_mem_map |= SECTION_IS_ONLINE;
 538         }
 539 }
 540
 541 #ifdef CONFIG_MEMORY_HOTREMOVE
 542 /* Mark all memory sections within the pfn range as online */
 543 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 544 {
 545         unsigned long pfn;
 546
 547         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 548                 unsigned long section_nr = pfn_to_section_nr(pfn);
 549                 struct mem_section *ms;
 550
 551                 /*
 552                  * TODO this needs some double checking. Offlining code makes
 553                  * sure to check pfn_valid but those checks might be just bogus
 554                  */
 555                 if (WARN_ON(!valid_section_nr(section_nr)))
 556                         continue;
 557
 558                 ms = __nr_to_section(section_nr);
 559                 ms->section_mem_map &= ~SECTION_IS_ONLINE;
 560         }
 561 }
 562 #endif
 563
 564 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 565 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 566                 struct vmem_altmap *altmap)
 567 {
 568         /* This will make the necessary allocations eventually. */
 569         return sparse_mem_map_populate(pnum, nid, altmap);
 570 }
 571 static void __kfree_section_memmap(struct page *memmap,
 572                 struct vmem_altmap *altmap)
 573 {
 574         unsigned long start = (unsigned long)memmap;
 575         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 576
 577         vmemmap_free(start, end, altmap);
 578 }
 579 #ifdef CONFIG_MEMORY_HOTREMOVE
 580 static void free_map_bootmem(struct page *memmap)
 581 {
 582         unsigned long start = (unsigned long)memmap;
 583         unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
 584
 585         vmemmap_free(start, end, NULL);
 586 }
 587 #endif /* CONFIG_MEMORY_HOTREMOVE */
 588 #else
 589 static struct page *__kmalloc_section_memmap(void)
 590 {
 591         struct page *page, *ret;
 592         unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
 593
 594         page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 595         if (page)
 596                 goto got_map_page;
 597
 598         ret = vmalloc(memmap_size);
 599         if (ret)
 600                 goto got_map_ptr;
 601
 602         return NULL;
 603 got_map_page:
 604         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
 605 got_map_ptr:
 606
 607         return ret;
 608 }
 609
 610 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 611                 struct vmem_altmap *altmap)
 612 {
 613         return __kmalloc_section_memmap();
 614 }
 615
 616 static void __kfree_section_memmap(struct page *memmap,
 617                 struct vmem_altmap *altmap)
 618 {
 619         if (is_vmalloc_addr(memmap))
 620                 vfree(memmap);
 621         else
 622                 free_pages((unsigned long)memmap,
 623                            get_order(sizeof(struct page) * PAGES_PER_SECTION));
 624 }
 625
 626 #ifdef CONFIG_MEMORY_HOTREMOVE
 627 static void free_map_bootmem(struct page *memmap)
 628 {
 629         unsigned long maps_section_nr, removing_section_nr, i;
 630         unsigned long magic, nr_pages;
 631         struct page *page = virt_to_page(memmap);
 632
 633         nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 634                 >> PAGE_SHIFT;
 635
 636         for (i = 0; i < nr_pages; i++, page++) {
 637                 magic = (unsigned long) page->freelist;
 638
 639                 BUG_ON(magic == NODE_INFO);
 640
 641                 maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
 642                 removing_section_nr = page_private(page);
 643
 644                 /*
 645                  * When this function is called, the removing section is
 646                  * logical offlined state. This means all pages are isolated
 647                  * from page allocator. If removing section's memmap is placed
 648                  * on the same section, it must not be freed.
 649                  * If it is freed, page allocator may allocate it which will
 650                  * be removed physically soon.
 651                  */
 652                 if (maps_section_nr != removing_section_nr)
 653                         put_page_bootmem(page);
 654         }
 655 }
 656 #endif /* CONFIG_MEMORY_HOTREMOVE */
 657 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 658
 659 /*
 660  * returns the number of sections whose mem_maps were properly
 661  * set.  If this is <=0, then that means that the passed-in
 662  * map was not consumed and must be freed.
 663  */
 664 int __meminit sparse_add_one_section(struct pglist_data *pgdat,
 665                 unsigned long start_pfn, struct vmem_altmap *altmap)
 666 {
 667         unsigned long section_nr = pfn_to_section_nr(start_pfn);
 668         struct mem_section *ms;
 669         struct page *memmap;
 670         unsigned long *usemap;
 671         unsigned long flags;
 672         int ret;
 673
 674         /*
 675          * no locking for this, because it does its own
 676          * plus, it does a kmalloc
 677          */
 678         ret = sparse_index_init(section_nr, pgdat->node_id);
 679         if (ret < 0 && ret != -EEXIST)
 680                 return ret;
 681         ret = 0;
 682         memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, altmap);
 683         if (!memmap)
 684                 return -ENOMEM;
 685         usemap = __kmalloc_section_usemap();
 686         if (!usemap) {
 687                 __kfree_section_memmap(memmap, altmap);
 688                 return -ENOMEM;
 689         }
 690
 691         pgdat_resize_lock(pgdat, &flags);
 692
 693         ms = __pfn_to_section(start_pfn);
 694         if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
 695                 ret = -EEXIST;
 696                 goto out;
 697         }
 698
 699 #ifdef CONFIG_DEBUG_VM
 700         /*
 701          * Poison uninitialized struct pages in order to catch invalid flags
 702          * combinations.
 703          */
 704         memset(memmap, PAGE_POISON_PATTERN, sizeof(struct page) * PAGES_PER_SECTION);
 705 #endif
 706
 707         section_mark_present(ms);
 708         sparse_init_one_section(ms, section_nr, memmap, usemap);
 709
 710 out:
 711         pgdat_resize_unlock(pgdat, &flags);
 712         if (ret < 0) {
 713                 kfree(usemap);
 714                 __kfree_section_memmap(memmap, altmap);
 715         }
 716         return ret;
 717 }
 718
 719 #ifdef CONFIG_MEMORY_HOTREMOVE
 720 #ifdef CONFIG_MEMORY_FAILURE
 721 static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 722 {
 723         int i;
 724
 725         if (!memmap)
 726                 return;
 727
 728         for (i = 0; i < nr_pages; i++) {
 729                 if (PageHWPoison(&memmap[i])) {
 730                         atomic_long_sub(1, &num_poisoned_pages);
 731                         ClearPageHWPoison(&memmap[i]);
 732                 }
 733         }
 734 }
 735 #else
 736 static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 737 {
 738 }
 739 #endif
 740
 741 static void free_section_usemap(struct page *memmap, unsigned long *usemap,
 742                 struct vmem_altmap *altmap)
 743 {
 744         struct page *usemap_page;
 745
 746         if (!usemap)
 747                 return;
 748
 749         usemap_page = virt_to_page(usemap);
 750         /*
 751          * Check to see if allocation came from hot-plug-add
 752          */
 753         if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
 754                 kfree(usemap);
 755                 if (memmap)
 756                         __kfree_section_memmap(memmap, altmap);
 757                 return;
 758         }
 759
 760         /*
 761          * The usemap came from bootmem. This is packed with other usemaps
 762          * on the section which has pgdat at boot time. Just keep it as is now.
 763          */
 764
 765         if (memmap)
 766                 free_map_bootmem(memmap);
 767 }
 768
 769 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
 770                 unsigned long map_offset, struct vmem_altmap *altmap)
 771 {
 772         struct page *memmap = NULL;
 773         unsigned long *usemap = NULL, flags;
 774         struct pglist_data *pgdat = zone->zone_pgdat;
 775
 776         pgdat_resize_lock(pgdat, &flags);
 777         if (ms->section_mem_map) {
 778                 usemap = ms->pageblock_flags;
 779                 memmap = sparse_decode_mem_map(ms->section_mem_map,
 780                                                 __section_nr(ms));
 781                 ms->section_mem_map = 0;
 782                 ms->pageblock_flags = NULL;
 783         }
 784         pgdat_resize_unlock(pgdat, &flags);
 785
 786         clear_hwpoisoned_pages(memmap + map_offset,
 787                         PAGES_PER_SECTION - map_offset);
 788         free_section_usemap(memmap, usemap, altmap);
 789 }
 790 #endif /* CONFIG_MEMORY_HOTREMOVE */
 791 #endif /* CONFIG_MEMORY_HOTPLUG */