linux/mm/sparse.c
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   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
  23struct mem_section *mem_section[NR_SECTION_ROOTS]
  24        ____cacheline_internodealigned_in_smp;
  25#else
  26struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
  27        ____cacheline_internodealigned_in_smp;
  28#endif
  29EXPORT_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
  38static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
  39#else
  40static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
  41#endif
  42
  43int page_to_nid(const struct page *page)
  44{
  45        return section_to_node_table[page_to_section(page)];
  46}
  47EXPORT_SYMBOL(page_to_nid);
  48
  49static 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 */
  54static inline void set_section_nid(unsigned long section_nr, int nid)
  55{
  56}
  57#endif
  58
  59#ifdef CONFIG_SPARSEMEM_EXTREME
  60static 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
  78static int __meminit sparse_index_init(unsigned long section_nr, int nid)
  79{
  80        unsigned long root = SECTION_NR_TO_ROOT(section_nr);
  81        struct mem_section *section;
  82
  83        if (mem_section[root])
  84                return -EEXIST;
  85
  86        section = sparse_index_alloc(nid);
  87        if (!section)
  88                return -ENOMEM;
  89
  90        mem_section[root] = section;
  91
  92        return 0;
  93}
  94#else /* !SPARSEMEM_EXTREME */
  95static inline int sparse_index_init(unsigned long section_nr, int nid)
  96{
  97        return 0;
  98}
  99#endif
 100
 101/*
 102 * Although written for the SPARSEMEM_EXTREME case, this happens
 103 * to also work for the flat array case because
 104 * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
 105 */
 106int __section_nr(struct mem_section* ms)
 107{
 108        unsigned long root_nr;
 109        struct mem_section* root;
 110
 111        for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {
 112                root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);
 113                if (!root)
 114                        continue;
 115
 116                if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))
 117                     break;
 118        }
 119
 120        VM_BUG_ON(root_nr == NR_SECTION_ROOTS);
 121
 122        return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
 123}
 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 */
 131static inline unsigned long sparse_encode_early_nid(int nid)
 132{
 133        return (nid << SECTION_NID_SHIFT);
 134}
 135
 136static 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 */
 142void __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/* Record a memory area against a node. */
 168void __init memory_present(int nid, unsigned long start, unsigned long end)
 169{
 170        unsigned long pfn;
 171
 172        start &= PAGE_SECTION_MASK;
 173        mminit_validate_memmodel_limits(&start, &end);
 174        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
 175                unsigned long section = pfn_to_section_nr(pfn);
 176                struct mem_section *ms;
 177
 178                sparse_index_init(section, nid);
 179                set_section_nid(section, nid);
 180
 181                ms = __nr_to_section(section);
 182                if (!ms->section_mem_map)
 183                        ms->section_mem_map = sparse_encode_early_nid(nid) |
 184                                                        SECTION_MARKED_PRESENT;
 185        }
 186}
 187
 188/*
 189 * Only used by the i386 NUMA architecures, but relatively
 190 * generic code.
 191 */
 192unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,
 193                                                     unsigned long end_pfn)
 194{
 195        unsigned long pfn;
 196        unsigned long nr_pages = 0;
 197
 198        mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
 199        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 200                if (nid != early_pfn_to_nid(pfn))
 201                        continue;
 202
 203                if (pfn_present(pfn))
 204                        nr_pages += PAGES_PER_SECTION;
 205        }
 206
 207        return nr_pages * sizeof(struct page);
 208}
 209
 210/*
 211 * Subtle, we encode the real pfn into the mem_map such that
 212 * the identity pfn - section_mem_map will return the actual
 213 * physical page frame number.
 214 */
 215static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
 216{
 217        return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
 218}
 219
 220/*
 221 * Decode mem_map from the coded memmap
 222 */
 223struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
 224{
 225        /* mask off the extra low bits of information */
 226        coded_mem_map &= SECTION_MAP_MASK;
 227        return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
 228}
 229
 230static int __meminit sparse_init_one_section(struct mem_section *ms,
 231                unsigned long pnum, struct page *mem_map,
 232                unsigned long *pageblock_bitmap)
 233{
 234        if (!present_section(ms))
 235                return -EINVAL;
 236
 237        ms->section_mem_map &= ~SECTION_MAP_MASK;
 238        ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
 239                                                        SECTION_HAS_MEM_MAP;
 240        ms->pageblock_flags = pageblock_bitmap;
 241
 242        return 1;
 243}
 244
 245unsigned long usemap_size(void)
 246{
 247        unsigned long size_bytes;
 248        size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
 249        size_bytes = roundup(size_bytes, sizeof(unsigned long));
 250        return size_bytes;
 251}
 252
 253#ifdef CONFIG_MEMORY_HOTPLUG
 254static unsigned long *__kmalloc_section_usemap(void)
 255{
 256        return kmalloc(usemap_size(), GFP_KERNEL);
 257}
 258#endif /* CONFIG_MEMORY_HOTPLUG */
 259
 260#ifdef CONFIG_MEMORY_HOTREMOVE
 261static unsigned long * __init
 262sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 263                                         unsigned long size)
 264{
 265        unsigned long goal, limit;
 266        unsigned long *p;
 267        int nid;
 268        /*
 269         * A page may contain usemaps for other sections preventing the
 270         * page being freed and making a section unremovable while
 271         * other sections referencing the usemap retmain active. Similarly,
 272         * a pgdat can prevent a section being removed. If section A
 273         * contains a pgdat and section B contains the usemap, both
 274         * sections become inter-dependent. This allocates usemaps
 275         * from the same section as the pgdat where possible to avoid
 276         * this problem.
 277         */
 278        goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
 279        limit = goal + (1UL << PA_SECTION_SHIFT);
 280        nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
 281again:
 282        p = ___alloc_bootmem_node_nopanic(NODE_DATA(nid), size,
 283                                          SMP_CACHE_BYTES, goal, limit);
 284        if (!p && limit) {
 285                limit = 0;
 286                goto again;
 287        }
 288        return p;
 289}
 290
 291static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 292{
 293        unsigned long usemap_snr, pgdat_snr;
 294        static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
 295        static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
 296        struct pglist_data *pgdat = NODE_DATA(nid);
 297        int usemap_nid;
 298
 299        usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
 300        pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
 301        if (usemap_snr == pgdat_snr)
 302                return;
 303
 304        if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
 305                /* skip redundant message */
 306                return;
 307
 308        old_usemap_snr = usemap_snr;
 309        old_pgdat_snr = pgdat_snr;
 310
 311        usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
 312        if (usemap_nid != nid) {
 313                printk(KERN_INFO
 314                       "node %d must be removed before remove section %ld\n",
 315                       nid, usemap_snr);
 316                return;
 317        }
 318        /*
 319         * There is a circular dependency.
 320         * Some platforms allow un-removable section because they will just
 321         * gather other removable sections for dynamic partitioning.
 322         * Just notify un-removable section's number here.
 323         */
 324        printk(KERN_INFO "Section %ld and %ld (node %d)", usemap_snr,
 325               pgdat_snr, nid);
 326        printk(KERN_CONT
 327               " have a circular dependency on usemap and pgdat allocations\n");
 328}
 329#else
 330static unsigned long * __init
 331sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 332                                         unsigned long size)
 333{
 334        return alloc_bootmem_node_nopanic(pgdat, size);
 335}
 336
 337static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 338{
 339}
 340#endif /* CONFIG_MEMORY_HOTREMOVE */
 341
 342static void __init sparse_early_usemaps_alloc_node(unsigned long**usemap_map,
 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        int size = usemap_size();
 350
 351        usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
 352                                                          size * usemap_count);
 353        if (!usemap) {
 354                printk(KERN_WARNING "%s: allocation failed\n", __func__);
 355                return;
 356        }
 357
 358        for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 359                if (!present_section_nr(pnum))
 360                        continue;
 361                usemap_map[pnum] = usemap;
 362                usemap += size;
 363                check_usemap_section_nr(nodeid, usemap_map[pnum]);
 364        }
 365}
 366
 367#ifndef CONFIG_SPARSEMEM_VMEMMAP
 368struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
 369{
 370        struct page *map;
 371        unsigned long size;
 372
 373        map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
 374        if (map)
 375                return map;
 376
 377        size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 378        map = __alloc_bootmem_node_high(NODE_DATA(nid), size,
 379                                         PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
 380        return map;
 381}
 382void __init sparse_mem_maps_populate_node(struct page **map_map,
 383                                          unsigned long pnum_begin,
 384                                          unsigned long pnum_end,
 385                                          unsigned long map_count, int nodeid)
 386{
 387        void *map;
 388        unsigned long pnum;
 389        unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
 390
 391        map = alloc_remap(nodeid, size * map_count);
 392        if (map) {
 393                for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 394                        if (!present_section_nr(pnum))
 395                                continue;
 396                        map_map[pnum] = map;
 397                        map += size;
 398                }
 399                return;
 400        }
 401
 402        size = PAGE_ALIGN(size);
 403        map = __alloc_bootmem_node_high(NODE_DATA(nodeid), size * map_count,
 404                                         PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
 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        /* fallback */
 416        for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 417                struct mem_section *ms;
 418
 419                if (!present_section_nr(pnum))
 420                        continue;
 421                map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
 422                if (map_map[pnum])
 423                        continue;
 424                ms = __nr_to_section(pnum);
 425                printk(KERN_ERR "%s: sparsemem memory map backing failed "
 426                        "some memory will not be available.\n", __func__);
 427                ms->section_mem_map = 0;
 428        }
 429}
 430#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 431
 432#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 433static void __init sparse_early_mem_maps_alloc_node(struct page **map_map,
 434                                 unsigned long pnum_begin,
 435                                 unsigned long pnum_end,
 436                                 unsigned long map_count, int nodeid)
 437{
 438        sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
 439                                         map_count, nodeid);
 440}
 441#else
 442static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
 443{
 444        struct page *map;
 445        struct mem_section *ms = __nr_to_section(pnum);
 446        int nid = sparse_early_nid(ms);
 447
 448        map = sparse_mem_map_populate(pnum, nid);
 449        if (map)
 450                return map;
 451
 452        printk(KERN_ERR "%s: sparsemem memory map backing failed "
 453                        "some memory will not be available.\n", __func__);
 454        ms->section_mem_map = 0;
 455        return NULL;
 456}
 457#endif
 458
 459void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
 460{
 461}
 462
 463/*
 464 * Allocate the accumulated non-linear sections, allocate a mem_map
 465 * for each and record the physical to section mapping.
 466 */
 467void __init sparse_init(void)
 468{
 469        unsigned long pnum;
 470        struct page *map;
 471        unsigned long *usemap;
 472        unsigned long **usemap_map;
 473        int size;
 474        int nodeid_begin = 0;
 475        unsigned long pnum_begin = 0;
 476        unsigned long usemap_count;
 477#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 478        unsigned long map_count;
 479        int size2;
 480        struct page **map_map;
 481#endif
 482
 483        /* see include/linux/mmzone.h 'struct mem_section' definition */
 484        BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
 485
 486        /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
 487        set_pageblock_order();
 488
 489        /*
 490         * map is using big page (aka 2M in x86 64 bit)
 491         * usemap is less one page (aka 24 bytes)
 492         * so alloc 2M (with 2M align) and 24 bytes in turn will
 493         * make next 2M slip to one more 2M later.
 494         * then in big system, the memory will have a lot of holes...
 495         * here try to allocate 2M pages continuously.
 496         *
 497         * powerpc need to call sparse_init_one_section right after each
 498         * sparse_early_mem_map_alloc, so allocate usemap_map at first.
 499         */
 500        size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
 501        usemap_map = alloc_bootmem(size);
 502        if (!usemap_map)
 503                panic("can not allocate usemap_map\n");
 504
 505        for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 506                struct mem_section *ms;
 507
 508                if (!present_section_nr(pnum))
 509                        continue;
 510                ms = __nr_to_section(pnum);
 511                nodeid_begin = sparse_early_nid(ms);
 512                pnum_begin = pnum;
 513                break;
 514        }
 515        usemap_count = 1;
 516        for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
 517                struct mem_section *ms;
 518                int nodeid;
 519
 520                if (!present_section_nr(pnum))
 521                        continue;
 522                ms = __nr_to_section(pnum);
 523                nodeid = sparse_early_nid(ms);
 524                if (nodeid == nodeid_begin) {
 525                        usemap_count++;
 526                        continue;
 527                }
 528                /* ok, we need to take cake of from pnum_begin to pnum - 1*/
 529                sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, pnum,
 530                                                 usemap_count, nodeid_begin);
 531                /* new start, update count etc*/
 532                nodeid_begin = nodeid;
 533                pnum_begin = pnum;
 534                usemap_count = 1;
 535        }
 536        /* ok, last chunk */
 537        sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, NR_MEM_SECTIONS,
 538                                         usemap_count, nodeid_begin);
 539
 540#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 541        size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
 542        map_map = alloc_bootmem(size2);
 543        if (!map_map)
 544                panic("can not allocate map_map\n");
 545
 546        for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 547                struct mem_section *ms;
 548
 549                if (!present_section_nr(pnum))
 550                        continue;
 551                ms = __nr_to_section(pnum);
 552                nodeid_begin = sparse_early_nid(ms);
 553                pnum_begin = pnum;
 554                break;
 555        }
 556        map_count = 1;
 557        for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
 558                struct mem_section *ms;
 559                int nodeid;
 560
 561                if (!present_section_nr(pnum))
 562                        continue;
 563                ms = __nr_to_section(pnum);
 564                nodeid = sparse_early_nid(ms);
 565                if (nodeid == nodeid_begin) {
 566                        map_count++;
 567                        continue;
 568                }
 569                /* ok, we need to take cake of from pnum_begin to pnum - 1*/
 570                sparse_early_mem_maps_alloc_node(map_map, pnum_begin, pnum,
 571                                                 map_count, nodeid_begin);
 572                /* new start, update count etc*/
 573                nodeid_begin = nodeid;
 574                pnum_begin = pnum;
 575                map_count = 1;
 576        }
 577        /* ok, last chunk */
 578        sparse_early_mem_maps_alloc_node(map_map, pnum_begin, NR_MEM_SECTIONS,
 579                                         map_count, nodeid_begin);
 580#endif
 581
 582        for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
 583                if (!present_section_nr(pnum))
 584                        continue;
 585
 586                usemap = usemap_map[pnum];
 587                if (!usemap)
 588                        continue;
 589
 590#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 591                map = map_map[pnum];
 592#else
 593                map = sparse_early_mem_map_alloc(pnum);
 594#endif
 595                if (!map)
 596                        continue;
 597
 598                sparse_init_one_section(__nr_to_section(pnum), pnum, map,
 599                                                                usemap);
 600        }
 601
 602        vmemmap_populate_print_last();
 603
 604#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
 605        free_bootmem(__pa(map_map), size2);
 606#endif
 607        free_bootmem(__pa(usemap_map), size);
 608}
 609
 610#ifdef CONFIG_MEMORY_HOTPLUG
 611#ifdef CONFIG_SPARSEMEM_VMEMMAP
 612static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 613                                                 unsigned long nr_pages)
 614{
 615        /* This will make the necessary allocations eventually. */
 616        return sparse_mem_map_populate(pnum, nid);
 617}
 618static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
 619{
 620        unsigned long start = (unsigned long)memmap;
 621        unsigned long end = (unsigned long)(memmap + nr_pages);
 622
 623        vmemmap_free(start, end);
 624}
 625#ifdef CONFIG_MEMORY_HOTREMOVE
 626static void free_map_bootmem(struct page *memmap, unsigned long nr_pages)
 627{
 628        unsigned long start = (unsigned long)memmap;
 629        unsigned long end = (unsigned long)(memmap + nr_pages);
 630
 631        vmemmap_free(start, end);
 632}
 633#endif /* CONFIG_MEMORY_HOTREMOVE */
 634#else
 635static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
 636{
 637        struct page *page, *ret;
 638        unsigned long memmap_size = sizeof(struct page) * nr_pages;
 639
 640        page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 641        if (page)
 642                goto got_map_page;
 643
 644        ret = vmalloc(memmap_size);
 645        if (ret)
 646                goto got_map_ptr;
 647
 648        return NULL;
 649got_map_page:
 650        ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
 651got_map_ptr:
 652
 653        return ret;
 654}
 655
 656static 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
 662static 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#ifdef CONFIG_MEMORY_HOTREMOVE
 672static void free_map_bootmem(struct page *memmap, unsigned long nr_pages)
 673{
 674        unsigned long maps_section_nr, removing_section_nr, i;
 675        unsigned long magic;
 676        struct page *page = virt_to_page(memmap);
 677
 678        for (i = 0; i < nr_pages; i++, page++) {
 679                magic = (unsigned long) page->lru.next;
 680
 681                BUG_ON(magic == NODE_INFO);
 682
 683                maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
 684                removing_section_nr = page->private;
 685
 686                /*
 687                 * When this function is called, the removing section is
 688                 * logical offlined state. This means all pages are isolated
 689                 * from page allocator. If removing section's memmap is placed
 690                 * on the same section, it must not be freed.
 691                 * If it is freed, page allocator may allocate it which will
 692                 * be removed physically soon.
 693                 */
 694                if (maps_section_nr != removing_section_nr)
 695                        put_page_bootmem(page);
 696        }
 697}
 698#endif /* CONFIG_MEMORY_HOTREMOVE */
 699#endif /* CONFIG_SPARSEMEM_VMEMMAP */
 700
 701/*
 702 * returns the number of sections whose mem_maps were properly
 703 * set.  If this is <=0, then that means that the passed-in
 704 * map was not consumed and must be freed.
 705 */
 706int __meminit sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
 707                           int nr_pages)
 708{
 709        unsigned long section_nr = pfn_to_section_nr(start_pfn);
 710        struct pglist_data *pgdat = zone->zone_pgdat;
 711        struct mem_section *ms;
 712        struct page *memmap;
 713        unsigned long *usemap;
 714        unsigned long flags;
 715        int ret;
 716
 717        /*
 718         * no locking for this, because it does its own
 719         * plus, it does a kmalloc
 720         */
 721        ret = sparse_index_init(section_nr, pgdat->node_id);
 722        if (ret < 0 && ret != -EEXIST)
 723                return ret;
 724        memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, nr_pages);
 725        if (!memmap)
 726                return -ENOMEM;
 727        usemap = __kmalloc_section_usemap();
 728        if (!usemap) {
 729                __kfree_section_memmap(memmap, nr_pages);
 730                return -ENOMEM;
 731        }
 732
 733        pgdat_resize_lock(pgdat, &flags);
 734
 735        ms = __pfn_to_section(start_pfn);
 736        if (ms->section_mem_map & SECTION_MARKED_PRESENT) {
 737                ret = -EEXIST;
 738                goto out;
 739        }
 740
 741        memset(memmap, 0, sizeof(struct page) * nr_pages);
 742
 743        ms->section_mem_map |= SECTION_MARKED_PRESENT;
 744
 745        ret = sparse_init_one_section(ms, section_nr, memmap, usemap);
 746
 747out:
 748        pgdat_resize_unlock(pgdat, &flags);
 749        if (ret <= 0) {
 750                kfree(usemap);
 751                __kfree_section_memmap(memmap, nr_pages);
 752        }
 753        return ret;
 754}
 755
 756#ifdef CONFIG_MEMORY_HOTREMOVE
 757#ifdef CONFIG_MEMORY_FAILURE
 758static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 759{
 760        int i;
 761
 762        if (!memmap)
 763                return;
 764
 765        for (i = 0; i < PAGES_PER_SECTION; i++) {
 766                if (PageHWPoison(&memmap[i])) {
 767                        atomic_long_sub(1, &num_poisoned_pages);
 768                        ClearPageHWPoison(&memmap[i]);
 769                }
 770        }
 771}
 772#else
 773static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 774{
 775}
 776#endif
 777
 778static void free_section_usemap(struct page *memmap, unsigned long *usemap)
 779{
 780        struct page *usemap_page;
 781        unsigned long nr_pages;
 782
 783        if (!usemap)
 784                return;
 785
 786        usemap_page = virt_to_page(usemap);
 787        /*
 788         * Check to see if allocation came from hot-plug-add
 789         */
 790        if (PageSlab(usemap_page) || PageCompound(usemap_page)) {
 791                kfree(usemap);
 792                if (memmap)
 793                        __kfree_section_memmap(memmap, PAGES_PER_SECTION);
 794                return;
 795        }
 796
 797        /*
 798         * The usemap came from bootmem. This is packed with other usemaps
 799         * on the section which has pgdat at boot time. Just keep it as is now.
 800         */
 801
 802        if (memmap) {
 803                nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 804                        >> PAGE_SHIFT;
 805
 806                free_map_bootmem(memmap, nr_pages);
 807        }
 808}
 809
 810void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
 811{
 812        struct page *memmap = NULL;
 813        unsigned long *usemap = NULL, flags;
 814        struct pglist_data *pgdat = zone->zone_pgdat;
 815
 816        pgdat_resize_lock(pgdat, &flags);
 817        if (ms->section_mem_map) {
 818                usemap = ms->pageblock_flags;
 819                memmap = sparse_decode_mem_map(ms->section_mem_map,
 820                                                __section_nr(ms));
 821                ms->section_mem_map = 0;
 822                ms->pageblock_flags = NULL;
 823        }
 824        pgdat_resize_unlock(pgdat, &flags);
 825
 826        clear_hwpoisoned_pages(memmap, PAGES_PER_SECTION);
 827        free_section_usemap(memmap, usemap);
 828}
 829#endif /* CONFIG_MEMORY_HOTREMOVE */
 830#endif /* CONFIG_MEMORY_HOTPLUG */
 831
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