linux/mm/memory_hotplug.c
<<
>>
Prefs
   1/*
   2 *  linux/mm/memory_hotplug.c
   3 *
   4 *  Copyright (C)
   5 */
   6
   7#include <linux/stddef.h>
   8#include <linux/mm.h>
   9#include <linux/swap.h>
  10#include <linux/interrupt.h>
  11#include <linux/pagemap.h>
  12#include <linux/bootmem.h>
  13#include <linux/compiler.h>
  14#include <linux/export.h>
  15#include <linux/pagevec.h>
  16#include <linux/writeback.h>
  17#include <linux/slab.h>
  18#include <linux/sysctl.h>
  19#include <linux/cpu.h>
  20#include <linux/memory.h>
  21#include <linux/memory_hotplug.h>
  22#include <linux/highmem.h>
  23#include <linux/vmalloc.h>
  24#include <linux/ioport.h>
  25#include <linux/delay.h>
  26#include <linux/migrate.h>
  27#include <linux/page-isolation.h>
  28#include <linux/pfn.h>
  29#include <linux/suspend.h>
  30#include <linux/mm_inline.h>
  31#include <linux/firmware-map.h>
  32#include <linux/stop_machine.h>
  33
  34#include <asm/tlbflush.h>
  35
  36#include "internal.h"
  37
  38/*
  39 * online_page_callback contains pointer to current page onlining function.
  40 * Initially it is generic_online_page(). If it is required it could be
  41 * changed by calling set_online_page_callback() for callback registration
  42 * and restore_online_page_callback() for generic callback restore.
  43 */
  44
  45static void generic_online_page(struct page *page);
  46
  47static online_page_callback_t online_page_callback = generic_online_page;
  48
  49DEFINE_MUTEX(mem_hotplug_mutex);
  50
  51void lock_memory_hotplug(void)
  52{
  53        mutex_lock(&mem_hotplug_mutex);
  54
  55        /* for exclusive hibernation if CONFIG_HIBERNATION=y */
  56        lock_system_sleep();
  57}
  58
  59void unlock_memory_hotplug(void)
  60{
  61        unlock_system_sleep();
  62        mutex_unlock(&mem_hotplug_mutex);
  63}
  64
  65
  66/* add this memory to iomem resource */
  67static struct resource *register_memory_resource(u64 start, u64 size)
  68{
  69        struct resource *res;
  70        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
  71        BUG_ON(!res);
  72
  73        res->name = "System RAM";
  74        res->start = start;
  75        res->end = start + size - 1;
  76        res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  77        if (request_resource(&iomem_resource, res) < 0) {
  78                printk("System RAM resource %pR cannot be added\n", res);
  79                kfree(res);
  80                res = NULL;
  81        }
  82        return res;
  83}
  84
  85static void release_memory_resource(struct resource *res)
  86{
  87        if (!res)
  88                return;
  89        release_resource(res);
  90        kfree(res);
  91        return;
  92}
  93
  94#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
  95void get_page_bootmem(unsigned long info,  struct page *page,
  96                      unsigned long type)
  97{
  98        page->lru.next = (struct list_head *) type;
  99        SetPagePrivate(page);
 100        set_page_private(page, info);
 101        atomic_inc(&page->_count);
 102}
 103
 104/* reference to __meminit __free_pages_bootmem is valid
 105 * so use __ref to tell modpost not to generate a warning */
 106void __ref put_page_bootmem(struct page *page)
 107{
 108        unsigned long type;
 109        static DEFINE_MUTEX(ppb_lock);
 110
 111        type = (unsigned long) page->lru.next;
 112        BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
 113               type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
 114
 115        if (atomic_dec_return(&page->_count) == 1) {
 116                ClearPagePrivate(page);
 117                set_page_private(page, 0);
 118                INIT_LIST_HEAD(&page->lru);
 119
 120                /*
 121                 * Please refer to comment for __free_pages_bootmem()
 122                 * for why we serialize here.
 123                 */
 124                mutex_lock(&ppb_lock);
 125                __free_pages_bootmem(page, 0);
 126                mutex_unlock(&ppb_lock);
 127                totalram_pages++;
 128        }
 129
 130}
 131
 132#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
 133#ifndef CONFIG_SPARSEMEM_VMEMMAP
 134static void register_page_bootmem_info_section(unsigned long start_pfn)
 135{
 136        unsigned long *usemap, mapsize, section_nr, i;
 137        struct mem_section *ms;
 138        struct page *page, *memmap;
 139
 140        section_nr = pfn_to_section_nr(start_pfn);
 141        ms = __nr_to_section(section_nr);
 142
 143        /* Get section's memmap address */
 144        memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 145
 146        /*
 147         * Get page for the memmap's phys address
 148         * XXX: need more consideration for sparse_vmemmap...
 149         */
 150        page = virt_to_page(memmap);
 151        mapsize = sizeof(struct page) * PAGES_PER_SECTION;
 152        mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
 153
 154        /* remember memmap's page */
 155        for (i = 0; i < mapsize; i++, page++)
 156                get_page_bootmem(section_nr, page, SECTION_INFO);
 157
 158        usemap = __nr_to_section(section_nr)->pageblock_flags;
 159        page = virt_to_page(usemap);
 160
 161        mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 162
 163        for (i = 0; i < mapsize; i++, page++)
 164                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 165
 166}
 167#else /* CONFIG_SPARSEMEM_VMEMMAP */
 168static void register_page_bootmem_info_section(unsigned long start_pfn)
 169{
 170        unsigned long *usemap, mapsize, section_nr, i;
 171        struct mem_section *ms;
 172        struct page *page, *memmap;
 173
 174        if (!pfn_valid(start_pfn))
 175                return;
 176
 177        section_nr = pfn_to_section_nr(start_pfn);
 178        ms = __nr_to_section(section_nr);
 179
 180        memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 181
 182        register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
 183
 184        usemap = __nr_to_section(section_nr)->pageblock_flags;
 185        page = virt_to_page(usemap);
 186
 187        mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 188
 189        for (i = 0; i < mapsize; i++, page++)
 190                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 191}
 192#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 193
 194void register_page_bootmem_info_node(struct pglist_data *pgdat)
 195{
 196        unsigned long i, pfn, end_pfn, nr_pages;
 197        int node = pgdat->node_id;
 198        struct page *page;
 199        struct zone *zone;
 200
 201        nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
 202        page = virt_to_page(pgdat);
 203
 204        for (i = 0; i < nr_pages; i++, page++)
 205                get_page_bootmem(node, page, NODE_INFO);
 206
 207        zone = &pgdat->node_zones[0];
 208        for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
 209                if (zone->wait_table) {
 210                        nr_pages = zone->wait_table_hash_nr_entries
 211                                * sizeof(wait_queue_head_t);
 212                        nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
 213                        page = virt_to_page(zone->wait_table);
 214
 215                        for (i = 0; i < nr_pages; i++, page++)
 216                                get_page_bootmem(node, page, NODE_INFO);
 217                }
 218        }
 219
 220        pfn = pgdat->node_start_pfn;
 221        end_pfn = pgdat_end_pfn(pgdat);
 222
 223        /* register_section info */
 224        for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 225                /*
 226                 * Some platforms can assign the same pfn to multiple nodes - on
 227                 * node0 as well as nodeN.  To avoid registering a pfn against
 228                 * multiple nodes we check that this pfn does not already
 229                 * reside in some other node.
 230                 */
 231                if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
 232                        register_page_bootmem_info_section(pfn);
 233        }
 234}
 235#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
 236
 237static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
 238                           unsigned long end_pfn)
 239{
 240        unsigned long old_zone_end_pfn;
 241
 242        zone_span_writelock(zone);
 243
 244        old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 245        if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
 246                zone->zone_start_pfn = start_pfn;
 247
 248        zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
 249                                zone->zone_start_pfn;
 250
 251        zone_span_writeunlock(zone);
 252}
 253
 254static void resize_zone(struct zone *zone, unsigned long start_pfn,
 255                unsigned long end_pfn)
 256{
 257        zone_span_writelock(zone);
 258
 259        if (end_pfn - start_pfn) {
 260                zone->zone_start_pfn = start_pfn;
 261                zone->spanned_pages = end_pfn - start_pfn;
 262        } else {
 263                /*
 264                 * make it consist as free_area_init_core(),
 265                 * if spanned_pages = 0, then keep start_pfn = 0
 266                 */
 267                zone->zone_start_pfn = 0;
 268                zone->spanned_pages = 0;
 269        }
 270
 271        zone_span_writeunlock(zone);
 272}
 273
 274static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
 275                unsigned long end_pfn)
 276{
 277        enum zone_type zid = zone_idx(zone);
 278        int nid = zone->zone_pgdat->node_id;
 279        unsigned long pfn;
 280
 281        for (pfn = start_pfn; pfn < end_pfn; pfn++)
 282                set_page_links(pfn_to_page(pfn), zid, nid, pfn);
 283}
 284
 285/* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
 286 * alloc_bootmem_node_nopanic() */
 287static int __ref ensure_zone_is_initialized(struct zone *zone,
 288                        unsigned long start_pfn, unsigned long num_pages)
 289{
 290        if (!zone_is_initialized(zone))
 291                return init_currently_empty_zone(zone, start_pfn, num_pages,
 292                                                 MEMMAP_HOTPLUG);
 293        return 0;
 294}
 295
 296static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
 297                unsigned long start_pfn, unsigned long end_pfn)
 298{
 299        int ret;
 300        unsigned long flags;
 301        unsigned long z1_start_pfn;
 302
 303        ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
 304        if (ret)
 305                return ret;
 306
 307        pgdat_resize_lock(z1->zone_pgdat, &flags);
 308
 309        /* can't move pfns which are higher than @z2 */
 310        if (end_pfn > zone_end_pfn(z2))
 311                goto out_fail;
 312        /* the move out part mast at the left most of @z2 */
 313        if (start_pfn > z2->zone_start_pfn)
 314                goto out_fail;
 315        /* must included/overlap */
 316        if (end_pfn <= z2->zone_start_pfn)
 317                goto out_fail;
 318
 319        /* use start_pfn for z1's start_pfn if z1 is empty */
 320        if (z1->spanned_pages)
 321                z1_start_pfn = z1->zone_start_pfn;
 322        else
 323                z1_start_pfn = start_pfn;
 324
 325        resize_zone(z1, z1_start_pfn, end_pfn);
 326        resize_zone(z2, end_pfn, zone_end_pfn(z2));
 327
 328        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 329
 330        fix_zone_id(z1, start_pfn, end_pfn);
 331
 332        return 0;
 333out_fail:
 334        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 335        return -1;
 336}
 337
 338static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
 339                unsigned long start_pfn, unsigned long end_pfn)
 340{
 341        int ret;
 342        unsigned long flags;
 343        unsigned long z2_end_pfn;
 344
 345        ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
 346        if (ret)
 347                return ret;
 348
 349        pgdat_resize_lock(z1->zone_pgdat, &flags);
 350
 351        /* can't move pfns which are lower than @z1 */
 352        if (z1->zone_start_pfn > start_pfn)
 353                goto out_fail;
 354        /* the move out part mast at the right most of @z1 */
 355        if (zone_end_pfn(z1) >  end_pfn)
 356                goto out_fail;
 357        /* must included/overlap */
 358        if (start_pfn >= zone_end_pfn(z1))
 359                goto out_fail;
 360
 361        /* use end_pfn for z2's end_pfn if z2 is empty */
 362        if (z2->spanned_pages)
 363                z2_end_pfn = zone_end_pfn(z2);
 364        else
 365                z2_end_pfn = end_pfn;
 366
 367        resize_zone(z1, z1->zone_start_pfn, start_pfn);
 368        resize_zone(z2, start_pfn, z2_end_pfn);
 369
 370        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 371
 372        fix_zone_id(z2, start_pfn, end_pfn);
 373
 374        return 0;
 375out_fail:
 376        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 377        return -1;
 378}
 379
 380static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
 381                            unsigned long end_pfn)
 382{
 383        unsigned long old_pgdat_end_pfn =
 384                pgdat->node_start_pfn + pgdat->node_spanned_pages;
 385
 386        if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
 387                pgdat->node_start_pfn = start_pfn;
 388
 389        pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
 390                                        pgdat->node_start_pfn;
 391}
 392
 393static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 394{
 395        struct pglist_data *pgdat = zone->zone_pgdat;
 396        int nr_pages = PAGES_PER_SECTION;
 397        int nid = pgdat->node_id;
 398        int zone_type;
 399        unsigned long flags;
 400        int ret;
 401
 402        zone_type = zone - pgdat->node_zones;
 403        ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
 404        if (ret)
 405                return ret;
 406
 407        pgdat_resize_lock(zone->zone_pgdat, &flags);
 408        grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
 409        grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
 410                        phys_start_pfn + nr_pages);
 411        pgdat_resize_unlock(zone->zone_pgdat, &flags);
 412        memmap_init_zone(nr_pages, nid, zone_type,
 413                         phys_start_pfn, MEMMAP_HOTPLUG);
 414        return 0;
 415}
 416
 417static int __meminit __add_section(int nid, struct zone *zone,
 418                                        unsigned long phys_start_pfn)
 419{
 420        int nr_pages = PAGES_PER_SECTION;
 421        int ret;
 422
 423        if (pfn_valid(phys_start_pfn))
 424                return -EEXIST;
 425
 426        ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
 427
 428        if (ret < 0)
 429                return ret;
 430
 431        ret = __add_zone(zone, phys_start_pfn);
 432
 433        if (ret < 0)
 434                return ret;
 435
 436        return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 437}
 438
 439/*
 440 * Reasonably generic function for adding memory.  It is
 441 * expected that archs that support memory hotplug will
 442 * call this function after deciding the zone to which to
 443 * add the new pages.
 444 */
 445int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 446                        unsigned long nr_pages)
 447{
 448        unsigned long i;
 449        int err = 0;
 450        int start_sec, end_sec;
 451        /* during initialize mem_map, align hot-added range to section */
 452        start_sec = pfn_to_section_nr(phys_start_pfn);
 453        end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 454
 455        for (i = start_sec; i <= end_sec; i++) {
 456                err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
 457
 458                /*
 459                 * EEXIST is finally dealt with by ioresource collision
 460                 * check. see add_memory() => register_memory_resource()
 461                 * Warning will be printed if there is collision.
 462                 */
 463                if (err && (err != -EEXIST))
 464                        break;
 465                err = 0;
 466        }
 467
 468        return err;
 469}
 470EXPORT_SYMBOL_GPL(__add_pages);
 471
 472#ifdef CONFIG_MEMORY_HOTREMOVE
 473/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
 474static int find_smallest_section_pfn(int nid, struct zone *zone,
 475                                     unsigned long start_pfn,
 476                                     unsigned long end_pfn)
 477{
 478        struct mem_section *ms;
 479
 480        for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
 481                ms = __pfn_to_section(start_pfn);
 482
 483                if (unlikely(!valid_section(ms)))
 484                        continue;
 485
 486                if (unlikely(pfn_to_nid(start_pfn) != nid))
 487                        continue;
 488
 489                if (zone && zone != page_zone(pfn_to_page(start_pfn)))
 490                        continue;
 491
 492                return start_pfn;
 493        }
 494
 495        return 0;
 496}
 497
 498/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
 499static int find_biggest_section_pfn(int nid, struct zone *zone,
 500                                    unsigned long start_pfn,
 501                                    unsigned long end_pfn)
 502{
 503        struct mem_section *ms;
 504        unsigned long pfn;
 505
 506        /* pfn is the end pfn of a memory section. */
 507        pfn = end_pfn - 1;
 508        for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
 509                ms = __pfn_to_section(pfn);
 510
 511                if (unlikely(!valid_section(ms)))
 512                        continue;
 513
 514                if (unlikely(pfn_to_nid(pfn) != nid))
 515                        continue;
 516
 517                if (zone && zone != page_zone(pfn_to_page(pfn)))
 518                        continue;
 519
 520                return pfn;
 521        }
 522
 523        return 0;
 524}
 525
 526static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
 527                             unsigned long end_pfn)
 528{
 529        unsigned long zone_start_pfn =  zone->zone_start_pfn;
 530        unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 531        unsigned long pfn;
 532        struct mem_section *ms;
 533        int nid = zone_to_nid(zone);
 534
 535        zone_span_writelock(zone);
 536        if (zone_start_pfn == start_pfn) {
 537                /*
 538                 * If the section is smallest section in the zone, it need
 539                 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
 540                 * In this case, we find second smallest valid mem_section
 541                 * for shrinking zone.
 542                 */
 543                pfn = find_smallest_section_pfn(nid, zone, end_pfn,
 544                                                zone_end_pfn);
 545                if (pfn) {
 546                        zone->zone_start_pfn = pfn;
 547                        zone->spanned_pages = zone_end_pfn - pfn;
 548                }
 549        } else if (zone_end_pfn == end_pfn) {
 550                /*
 551                 * If the section is biggest section in the zone, it need
 552                 * shrink zone->spanned_pages.
 553                 * In this case, we find second biggest valid mem_section for
 554                 * shrinking zone.
 555                 */
 556                pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
 557                                               start_pfn);
 558                if (pfn)
 559                        zone->spanned_pages = pfn - zone_start_pfn + 1;
 560        }
 561
 562        /*
 563         * The section is not biggest or smallest mem_section in the zone, it
 564         * only creates a hole in the zone. So in this case, we need not
 565         * change the zone. But perhaps, the zone has only hole data. Thus
 566         * it check the zone has only hole or not.
 567         */
 568        pfn = zone_start_pfn;
 569        for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
 570                ms = __pfn_to_section(pfn);
 571
 572                if (unlikely(!valid_section(ms)))
 573                        continue;
 574
 575                if (page_zone(pfn_to_page(pfn)) != zone)
 576                        continue;
 577
 578                 /* If the section is current section, it continues the loop */
 579                if (start_pfn == pfn)
 580                        continue;
 581
 582                /* If we find valid section, we have nothing to do */
 583                zone_span_writeunlock(zone);
 584                return;
 585        }
 586
 587        /* The zone has no valid section */
 588        zone->zone_start_pfn = 0;
 589        zone->spanned_pages = 0;
 590        zone_span_writeunlock(zone);
 591}
 592
 593static void shrink_pgdat_span(struct pglist_data *pgdat,
 594                              unsigned long start_pfn, unsigned long end_pfn)
 595{
 596        unsigned long pgdat_start_pfn =  pgdat->node_start_pfn;
 597        unsigned long pgdat_end_pfn =
 598                pgdat->node_start_pfn + pgdat->node_spanned_pages;
 599        unsigned long pfn;
 600        struct mem_section *ms;
 601        int nid = pgdat->node_id;
 602
 603        if (pgdat_start_pfn == start_pfn) {
 604                /*
 605                 * If the section is smallest section in the pgdat, it need
 606                 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
 607                 * In this case, we find second smallest valid mem_section
 608                 * for shrinking zone.
 609                 */
 610                pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
 611                                                pgdat_end_pfn);
 612                if (pfn) {
 613                        pgdat->node_start_pfn = pfn;
 614                        pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
 615                }
 616        } else if (pgdat_end_pfn == end_pfn) {
 617                /*
 618                 * If the section is biggest section in the pgdat, it need
 619                 * shrink pgdat->node_spanned_pages.
 620                 * In this case, we find second biggest valid mem_section for
 621                 * shrinking zone.
 622                 */
 623                pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
 624                                               start_pfn);
 625                if (pfn)
 626                        pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
 627        }
 628
 629        /*
 630         * If the section is not biggest or smallest mem_section in the pgdat,
 631         * it only creates a hole in the pgdat. So in this case, we need not
 632         * change the pgdat.
 633         * But perhaps, the pgdat has only hole data. Thus it check the pgdat
 634         * has only hole or not.
 635         */
 636        pfn = pgdat_start_pfn;
 637        for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
 638                ms = __pfn_to_section(pfn);
 639
 640                if (unlikely(!valid_section(ms)))
 641                        continue;
 642
 643                if (pfn_to_nid(pfn) != nid)
 644                        continue;
 645
 646                 /* If the section is current section, it continues the loop */
 647                if (start_pfn == pfn)
 648                        continue;
 649
 650                /* If we find valid section, we have nothing to do */
 651                return;
 652        }
 653
 654        /* The pgdat has no valid section */
 655        pgdat->node_start_pfn = 0;
 656        pgdat->node_spanned_pages = 0;
 657}
 658
 659static void __remove_zone(struct zone *zone, unsigned long start_pfn)
 660{
 661        struct pglist_data *pgdat = zone->zone_pgdat;
 662        int nr_pages = PAGES_PER_SECTION;
 663        int zone_type;
 664        unsigned long flags;
 665
 666        zone_type = zone - pgdat->node_zones;
 667
 668        pgdat_resize_lock(zone->zone_pgdat, &flags);
 669        shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
 670        shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
 671        pgdat_resize_unlock(zone->zone_pgdat, &flags);
 672}
 673
 674static int __remove_section(struct zone *zone, struct mem_section *ms)
 675{
 676        unsigned long start_pfn;
 677        int scn_nr;
 678        int ret = -EINVAL;
 679
 680        if (!valid_section(ms))
 681                return ret;
 682
 683        ret = unregister_memory_section(ms);
 684        if (ret)
 685                return ret;
 686
 687        scn_nr = __section_nr(ms);
 688        start_pfn = section_nr_to_pfn(scn_nr);
 689        __remove_zone(zone, start_pfn);
 690
 691        sparse_remove_one_section(zone, ms);
 692        return 0;
 693}
 694
 695/**
 696 * __remove_pages() - remove sections of pages from a zone
 697 * @zone: zone from which pages need to be removed
 698 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
 699 * @nr_pages: number of pages to remove (must be multiple of section size)
 700 *
 701 * Generic helper function to remove section mappings and sysfs entries
 702 * for the section of the memory we are removing. Caller needs to make
 703 * sure that pages are marked reserved and zones are adjust properly by
 704 * calling offline_pages().
 705 */
 706int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 707                 unsigned long nr_pages)
 708{
 709        unsigned long i;
 710        int sections_to_remove;
 711        resource_size_t start, size;
 712        int ret = 0;
 713
 714        /*
 715         * We can only remove entire sections
 716         */
 717        BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 718        BUG_ON(nr_pages % PAGES_PER_SECTION);
 719
 720        start = phys_start_pfn << PAGE_SHIFT;
 721        size = nr_pages * PAGE_SIZE;
 722        ret = release_mem_region_adjustable(&iomem_resource, start, size);
 723        if (ret) {
 724                resource_size_t endres = start + size - 1;
 725
 726                pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
 727                                &start, &endres, ret);
 728        }
 729
 730        sections_to_remove = nr_pages / PAGES_PER_SECTION;
 731        for (i = 0; i < sections_to_remove; i++) {
 732                unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 733                ret = __remove_section(zone, __pfn_to_section(pfn));
 734                if (ret)
 735                        break;
 736        }
 737        return ret;
 738}
 739EXPORT_SYMBOL_GPL(__remove_pages);
 740#endif /* CONFIG_MEMORY_HOTREMOVE */
 741
 742int set_online_page_callback(online_page_callback_t callback)
 743{
 744        int rc = -EINVAL;
 745
 746        lock_memory_hotplug();
 747
 748        if (online_page_callback == generic_online_page) {
 749                online_page_callback = callback;
 750                rc = 0;
 751        }
 752
 753        unlock_memory_hotplug();
 754
 755        return rc;
 756}
 757EXPORT_SYMBOL_GPL(set_online_page_callback);
 758
 759int restore_online_page_callback(online_page_callback_t callback)
 760{
 761        int rc = -EINVAL;
 762
 763        lock_memory_hotplug();
 764
 765        if (online_page_callback == callback) {
 766                online_page_callback = generic_online_page;
 767                rc = 0;
 768        }
 769
 770        unlock_memory_hotplug();
 771
 772        return rc;
 773}
 774EXPORT_SYMBOL_GPL(restore_online_page_callback);
 775
 776void __online_page_set_limits(struct page *page)
 777{
 778        unsigned long pfn = page_to_pfn(page);
 779
 780        if (pfn >= num_physpages)
 781                num_physpages = pfn + 1;
 782}
 783EXPORT_SYMBOL_GPL(__online_page_set_limits);
 784
 785void __online_page_increment_counters(struct page *page)
 786{
 787        totalram_pages++;
 788
 789#ifdef CONFIG_HIGHMEM
 790        if (PageHighMem(page))
 791                totalhigh_pages++;
 792#endif
 793}
 794EXPORT_SYMBOL_GPL(__online_page_increment_counters);
 795
 796void __online_page_free(struct page *page)
 797{
 798        ClearPageReserved(page);
 799        init_page_count(page);
 800        __free_page(page);
 801}
 802EXPORT_SYMBOL_GPL(__online_page_free);
 803
 804static void generic_online_page(struct page *page)
 805{
 806        __online_page_set_limits(page);
 807        __online_page_increment_counters(page);
 808        __online_page_free(page);
 809}
 810
 811static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 812                        void *arg)
 813{
 814        unsigned long i;
 815        unsigned long onlined_pages = *(unsigned long *)arg;
 816        struct page *page;
 817        if (PageReserved(pfn_to_page(start_pfn)))
 818                for (i = 0; i < nr_pages; i++) {
 819                        page = pfn_to_page(start_pfn + i);
 820                        (*online_page_callback)(page);
 821                        onlined_pages++;
 822                }
 823        *(unsigned long *)arg = onlined_pages;
 824        return 0;
 825}
 826
 827#ifdef CONFIG_MOVABLE_NODE
 828/*
 829 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
 830 * normal memory.
 831 */
 832static bool can_online_high_movable(struct zone *zone)
 833{
 834        return true;
 835}
 836#else /* CONFIG_MOVABLE_NODE */
 837/* ensure every online node has NORMAL memory */
 838static bool can_online_high_movable(struct zone *zone)
 839{
 840        return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
 841}
 842#endif /* CONFIG_MOVABLE_NODE */
 843
 844/* check which state of node_states will be changed when online memory */
 845static void node_states_check_changes_online(unsigned long nr_pages,
 846        struct zone *zone, struct memory_notify *arg)
 847{
 848        int nid = zone_to_nid(zone);
 849        enum zone_type zone_last = ZONE_NORMAL;
 850
 851        /*
 852         * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
 853         * contains nodes which have zones of 0...ZONE_NORMAL,
 854         * set zone_last to ZONE_NORMAL.
 855         *
 856         * If we don't have HIGHMEM nor movable node,
 857         * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
 858         * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
 859         */
 860        if (N_MEMORY == N_NORMAL_MEMORY)
 861                zone_last = ZONE_MOVABLE;
 862
 863        /*
 864         * if the memory to be online is in a zone of 0...zone_last, and
 865         * the zones of 0...zone_last don't have memory before online, we will
 866         * need to set the node to node_states[N_NORMAL_MEMORY] after
 867         * the memory is online.
 868         */
 869        if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
 870                arg->status_change_nid_normal = nid;
 871        else
 872                arg->status_change_nid_normal = -1;
 873
 874#ifdef CONFIG_HIGHMEM
 875        /*
 876         * If we have movable node, node_states[N_HIGH_MEMORY]
 877         * contains nodes which have zones of 0...ZONE_HIGHMEM,
 878         * set zone_last to ZONE_HIGHMEM.
 879         *
 880         * If we don't have movable node, node_states[N_NORMAL_MEMORY]
 881         * contains nodes which have zones of 0...ZONE_MOVABLE,
 882         * set zone_last to ZONE_MOVABLE.
 883         */
 884        zone_last = ZONE_HIGHMEM;
 885        if (N_MEMORY == N_HIGH_MEMORY)
 886                zone_last = ZONE_MOVABLE;
 887
 888        if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
 889                arg->status_change_nid_high = nid;
 890        else
 891                arg->status_change_nid_high = -1;
 892#else
 893        arg->status_change_nid_high = arg->status_change_nid_normal;
 894#endif
 895
 896        /*
 897         * if the node don't have memory befor online, we will need to
 898         * set the node to node_states[N_MEMORY] after the memory
 899         * is online.
 900         */
 901        if (!node_state(nid, N_MEMORY))
 902                arg->status_change_nid = nid;
 903        else
 904                arg->status_change_nid = -1;
 905}
 906
 907static void node_states_set_node(int node, struct memory_notify *arg)
 908{
 909        if (arg->status_change_nid_normal >= 0)
 910                node_set_state(node, N_NORMAL_MEMORY);
 911
 912        if (arg->status_change_nid_high >= 0)
 913                node_set_state(node, N_HIGH_MEMORY);
 914
 915        node_set_state(node, N_MEMORY);
 916}
 917
 918
 919int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
 920{
 921        unsigned long onlined_pages = 0;
 922        struct zone *zone;
 923        int need_zonelists_rebuild = 0;
 924        int nid;
 925        int ret;
 926        struct memory_notify arg;
 927
 928        lock_memory_hotplug();
 929        /*
 930         * This doesn't need a lock to do pfn_to_page().
 931         * The section can't be removed here because of the
 932         * memory_block->state_mutex.
 933         */
 934        zone = page_zone(pfn_to_page(pfn));
 935
 936        if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
 937            !can_online_high_movable(zone)) {
 938                unlock_memory_hotplug();
 939                return -1;
 940        }
 941
 942        if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
 943                if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
 944                        unlock_memory_hotplug();
 945                        return -1;
 946                }
 947        }
 948        if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
 949                if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
 950                        unlock_memory_hotplug();
 951                        return -1;
 952                }
 953        }
 954
 955        /* Previous code may changed the zone of the pfn range */
 956        zone = page_zone(pfn_to_page(pfn));
 957
 958        arg.start_pfn = pfn;
 959        arg.nr_pages = nr_pages;
 960        node_states_check_changes_online(nr_pages, zone, &arg);
 961
 962        nid = page_to_nid(pfn_to_page(pfn));
 963
 964        ret = memory_notify(MEM_GOING_ONLINE, &arg);
 965        ret = notifier_to_errno(ret);
 966        if (ret) {
 967                memory_notify(MEM_CANCEL_ONLINE, &arg);
 968                unlock_memory_hotplug();
 969                return ret;
 970        }
 971        /*
 972         * If this zone is not populated, then it is not in zonelist.
 973         * This means the page allocator ignores this zone.
 974         * So, zonelist must be updated after online.
 975         */
 976        mutex_lock(&zonelists_mutex);
 977        if (!populated_zone(zone)) {
 978                need_zonelists_rebuild = 1;
 979                build_all_zonelists(NULL, zone);
 980        }
 981
 982        ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
 983                online_pages_range);
 984        if (ret) {
 985                if (need_zonelists_rebuild)
 986                        zone_pcp_reset(zone);
 987                mutex_unlock(&zonelists_mutex);
 988                printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
 989                       (unsigned long long) pfn << PAGE_SHIFT,
 990                       (((unsigned long long) pfn + nr_pages)
 991                            << PAGE_SHIFT) - 1);
 992                memory_notify(MEM_CANCEL_ONLINE, &arg);
 993                unlock_memory_hotplug();
 994                return ret;
 995        }
 996
 997        zone->managed_pages += onlined_pages;
 998        zone->present_pages += onlined_pages;
 999        zone->zone_pgdat->node_present_pages += onlined_pages;
1000        if (onlined_pages) {
1001                node_states_set_node(zone_to_nid(zone), &arg);
1002                if (need_zonelists_rebuild)
1003                        build_all_zonelists(NULL, NULL);
1004                else
1005                        zone_pcp_update(zone);
1006        }
1007
1008        mutex_unlock(&zonelists_mutex);
1009
1010        init_per_zone_wmark_min();
1011
1012        if (onlined_pages)
1013                kswapd_run(zone_to_nid(zone));
1014
1015        vm_total_pages = nr_free_pagecache_pages();
1016
1017        writeback_set_ratelimit();
1018
1019        if (onlined_pages)
1020                memory_notify(MEM_ONLINE, &arg);
1021        unlock_memory_hotplug();
1022
1023        return 0;
1024}
1025#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1026
1027/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1028static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1029{
1030        struct pglist_data *pgdat;
1031        unsigned long zones_size[MAX_NR_ZONES] = {0};
1032        unsigned long zholes_size[MAX_NR_ZONES] = {0};
1033        unsigned long start_pfn = start >> PAGE_SHIFT;
1034
1035        pgdat = NODE_DATA(nid);
1036        if (!pgdat) {
1037                pgdat = arch_alloc_nodedata(nid);
1038                if (!pgdat)
1039                        return NULL;
1040
1041                arch_refresh_nodedata(nid, pgdat);
1042        }
1043
1044        /* we can use NODE_DATA(nid) from here */
1045
1046        /* init node's zones as empty zones, we don't have any present pages.*/
1047        free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1048
1049        /*
1050         * The node we allocated has no zone fallback lists. For avoiding
1051         * to access not-initialized zonelist, build here.
1052         */
1053        mutex_lock(&zonelists_mutex);
1054        build_all_zonelists(pgdat, NULL);
1055        mutex_unlock(&zonelists_mutex);
1056
1057        return pgdat;
1058}
1059
1060static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1061{
1062        arch_refresh_nodedata(nid, NULL);
1063        arch_free_nodedata(pgdat);
1064        return;
1065}
1066
1067
1068/*
1069 * called by cpu_up() to online a node without onlined memory.
1070 */
1071int mem_online_node(int nid)
1072{
1073        pg_data_t       *pgdat;
1074        int     ret;
1075
1076        lock_memory_hotplug();
1077        pgdat = hotadd_new_pgdat(nid, 0);
1078        if (!pgdat) {
1079                ret = -ENOMEM;
1080                goto out;
1081        }
1082        node_set_online(nid);
1083        ret = register_one_node(nid);
1084        BUG_ON(ret);
1085
1086out:
1087        unlock_memory_hotplug();
1088        return ret;
1089}
1090
1091/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1092int __ref add_memory(int nid, u64 start, u64 size)
1093{
1094        pg_data_t *pgdat = NULL;
1095        bool new_pgdat;
1096        bool new_node;
1097        struct resource *res;
1098        int ret;
1099
1100        lock_memory_hotplug();
1101
1102        res = register_memory_resource(start, size);
1103        ret = -EEXIST;
1104        if (!res)
1105                goto out;
1106
1107        {       /* Stupid hack to suppress address-never-null warning */
1108                void *p = NODE_DATA(nid);
1109                new_pgdat = !p;
1110        }
1111        new_node = !node_online(nid);
1112        if (new_node) {
1113                pgdat = hotadd_new_pgdat(nid, start);
1114                ret = -ENOMEM;
1115                if (!pgdat)
1116                        goto error;
1117        }
1118
1119        /* call arch's memory hotadd */
1120        ret = arch_add_memory(nid, start, size);
1121
1122        if (ret < 0)
1123                goto error;
1124
1125        /* we online node here. we can't roll back from here. */
1126        node_set_online(nid);
1127
1128        if (new_node) {
1129                ret = register_one_node(nid);
1130                /*
1131                 * If sysfs file of new node can't create, cpu on the node
1132                 * can't be hot-added. There is no rollback way now.
1133                 * So, check by BUG_ON() to catch it reluctantly..
1134                 */
1135                BUG_ON(ret);
1136        }
1137
1138        /* create new memmap entry */
1139        firmware_map_add_hotplug(start, start + size, "System RAM");
1140
1141        goto out;
1142
1143error:
1144        /* rollback pgdat allocation and others */
1145        if (new_pgdat)
1146                rollback_node_hotadd(nid, pgdat);
1147        release_memory_resource(res);
1148
1149out:
1150        unlock_memory_hotplug();
1151        return ret;
1152}
1153EXPORT_SYMBOL_GPL(add_memory);
1154
1155#ifdef CONFIG_MEMORY_HOTREMOVE
1156/*
1157 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1158 * set and the size of the free page is given by page_order(). Using this,
1159 * the function determines if the pageblock contains only free pages.
1160 * Due to buddy contraints, a free page at least the size of a pageblock will
1161 * be located at the start of the pageblock
1162 */
1163static inline int pageblock_free(struct page *page)
1164{
1165        return PageBuddy(page) && page_order(page) >= pageblock_order;
1166}
1167
1168/* Return the start of the next active pageblock after a given page */
1169static struct page *next_active_pageblock(struct page *page)
1170{
1171        /* Ensure the starting page is pageblock-aligned */
1172        BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1173
1174        /* If the entire pageblock is free, move to the end of free page */
1175        if (pageblock_free(page)) {
1176                int order;
1177                /* be careful. we don't have locks, page_order can be changed.*/
1178                order = page_order(page);
1179                if ((order < MAX_ORDER) && (order >= pageblock_order))
1180                        return page + (1 << order);
1181        }
1182
1183        return page + pageblock_nr_pages;
1184}
1185
1186/* Checks if this range of memory is likely to be hot-removable. */
1187int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1188{
1189        struct page *page = pfn_to_page(start_pfn);
1190        struct page *end_page = page + nr_pages;
1191
1192        /* Check the starting page of each pageblock within the range */
1193        for (; page < end_page; page = next_active_pageblock(page)) {
1194                if (!is_pageblock_removable_nolock(page))
1195                        return 0;
1196                cond_resched();
1197        }
1198
1199        /* All pageblocks in the memory block are likely to be hot-removable */
1200        return 1;
1201}
1202
1203/*
1204 * Confirm all pages in a range [start, end) is belongs to the same zone.
1205 */
1206static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
1207{
1208        unsigned long pfn;
1209        struct zone *zone = NULL;
1210        struct page *page;
1211        int i;
1212        for (pfn = start_pfn;
1213             pfn < end_pfn;
1214             pfn += MAX_ORDER_NR_PAGES) {
1215                i = 0;
1216                /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1217                while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
1218                        i++;
1219                if (i == MAX_ORDER_NR_PAGES)
1220                        continue;
1221                page = pfn_to_page(pfn + i);
1222                if (zone && page_zone(page) != zone)
1223                        return 0;
1224                zone = page_zone(page);
1225        }
1226        return 1;
1227}
1228
1229/*
1230 * Scanning pfn is much easier than scanning lru list.
1231 * Scan pfn from start to end and Find LRU page.
1232 */
1233static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
1234{
1235        unsigned long pfn;
1236        struct page *page;
1237        for (pfn = start; pfn < end; pfn++) {
1238                if (pfn_valid(pfn)) {
1239                        page = pfn_to_page(pfn);
1240                        if (PageLRU(page))
1241                                return pfn;
1242                }
1243        }
1244        return 0;
1245}
1246
1247#define NR_OFFLINE_AT_ONCE_PAGES        (256)
1248static int
1249do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1250{
1251        unsigned long pfn;
1252        struct page *page;
1253        int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1254        int not_managed = 0;
1255        int ret = 0;
1256        LIST_HEAD(source);
1257
1258        for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1259                if (!pfn_valid(pfn))
1260                        continue;
1261                page = pfn_to_page(pfn);
1262                if (!get_page_unless_zero(page))
1263                        continue;
1264                /*
1265                 * We can skip free pages. And we can only deal with pages on
1266                 * LRU.
1267                 */
1268                ret = isolate_lru_page(page);
1269                if (!ret) { /* Success */
1270                        put_page(page);
1271                        list_add_tail(&page->lru, &source);
1272                        move_pages--;
1273                        inc_zone_page_state(page, NR_ISOLATED_ANON +
1274                                            page_is_file_cache(page));
1275
1276                } else {
1277#ifdef CONFIG_DEBUG_VM
1278                        printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
1279                               pfn);
1280                        dump_page(page);
1281#endif
1282                        put_page(page);
1283                        /* Because we don't have big zone->lock. we should
1284                           check this again here. */
1285                        if (page_count(page)) {
1286                                not_managed++;
1287                                ret = -EBUSY;
1288                                break;
1289                        }
1290                }
1291        }
1292        if (!list_empty(&source)) {
1293                if (not_managed) {
1294                        putback_lru_pages(&source);
1295                        goto out;
1296                }
1297
1298                /*
1299                 * alloc_migrate_target should be improooooved!!
1300                 * migrate_pages returns # of failed pages.
1301                 */
1302                ret = migrate_pages(&source, alloc_migrate_target, 0,
1303                                        MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1304                if (ret)
1305                        putback_lru_pages(&source);
1306        }
1307out:
1308        return ret;
1309}
1310
1311/*
1312 * remove from free_area[] and mark all as Reserved.
1313 */
1314static int
1315offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1316                        void *data)
1317{
1318        __offline_isolated_pages(start, start + nr_pages);
1319        return 0;
1320}
1321
1322static void
1323offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1324{
1325        walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1326                                offline_isolated_pages_cb);
1327}
1328
1329/*
1330 * Check all pages in range, recoreded as memory resource, are isolated.
1331 */
1332static int
1333check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1334                        void *data)
1335{
1336        int ret;
1337        long offlined = *(long *)data;
1338        ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1339        offlined = nr_pages;
1340        if (!ret)
1341                *(long *)data += offlined;
1342        return ret;
1343}
1344
1345static long
1346check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1347{
1348        long offlined = 0;
1349        int ret;
1350
1351        ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1352                        check_pages_isolated_cb);
1353        if (ret < 0)
1354                offlined = (long)ret;
1355        return offlined;
1356}
1357
1358#ifdef CONFIG_MOVABLE_NODE
1359/*
1360 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1361 * normal memory.
1362 */
1363static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1364{
1365        return true;
1366}
1367#else /* CONFIG_MOVABLE_NODE */
1368/* ensure the node has NORMAL memory if it is still online */
1369static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1370{
1371        struct pglist_data *pgdat = zone->zone_pgdat;
1372        unsigned long present_pages = 0;
1373        enum zone_type zt;
1374
1375        for (zt = 0; zt <= ZONE_NORMAL; zt++)
1376                present_pages += pgdat->node_zones[zt].present_pages;
1377
1378        if (present_pages > nr_pages)
1379                return true;
1380
1381        present_pages = 0;
1382        for (; zt <= ZONE_MOVABLE; zt++)
1383                present_pages += pgdat->node_zones[zt].present_pages;
1384
1385        /*
1386         * we can't offline the last normal memory until all
1387         * higher memory is offlined.
1388         */
1389        return present_pages == 0;
1390}
1391#endif /* CONFIG_MOVABLE_NODE */
1392
1393/* check which state of node_states will be changed when offline memory */
1394static void node_states_check_changes_offline(unsigned long nr_pages,
1395                struct zone *zone, struct memory_notify *arg)
1396{
1397        struct pglist_data *pgdat = zone->zone_pgdat;
1398        unsigned long present_pages = 0;
1399        enum zone_type zt, zone_last = ZONE_NORMAL;
1400
1401        /*
1402         * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1403         * contains nodes which have zones of 0...ZONE_NORMAL,
1404         * set zone_last to ZONE_NORMAL.
1405         *
1406         * If we don't have HIGHMEM nor movable node,
1407         * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1408         * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1409         */
1410        if (N_MEMORY == N_NORMAL_MEMORY)
1411                zone_last = ZONE_MOVABLE;
1412
1413        /*
1414         * check whether node_states[N_NORMAL_MEMORY] will be changed.
1415         * If the memory to be offline is in a zone of 0...zone_last,
1416         * and it is the last present memory, 0...zone_last will
1417         * become empty after offline , thus we can determind we will
1418         * need to clear the node from node_states[N_NORMAL_MEMORY].
1419         */
1420        for (zt = 0; zt <= zone_last; zt++)
1421                present_pages += pgdat->node_zones[zt].present_pages;
1422        if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1423                arg->status_change_nid_normal = zone_to_nid(zone);
1424        else
1425                arg->status_change_nid_normal = -1;
1426
1427#ifdef CONFIG_HIGHMEM
1428        /*
1429         * If we have movable node, node_states[N_HIGH_MEMORY]
1430         * contains nodes which have zones of 0...ZONE_HIGHMEM,
1431         * set zone_last to ZONE_HIGHMEM.
1432         *
1433         * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1434         * contains nodes which have zones of 0...ZONE_MOVABLE,
1435         * set zone_last to ZONE_MOVABLE.
1436         */
1437        zone_last = ZONE_HIGHMEM;
1438        if (N_MEMORY == N_HIGH_MEMORY)
1439                zone_last = ZONE_MOVABLE;
1440
1441        for (; zt <= zone_last; zt++)
1442                present_pages += pgdat->node_zones[zt].present_pages;
1443        if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1444                arg->status_change_nid_high = zone_to_nid(zone);
1445        else
1446                arg->status_change_nid_high = -1;
1447#else
1448        arg->status_change_nid_high = arg->status_change_nid_normal;
1449#endif
1450
1451        /*
1452         * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1453         */
1454        zone_last = ZONE_MOVABLE;
1455
1456        /*
1457         * check whether node_states[N_HIGH_MEMORY] will be changed
1458         * If we try to offline the last present @nr_pages from the node,
1459         * we can determind we will need to clear the node from
1460         * node_states[N_HIGH_MEMORY].
1461         */
1462        for (; zt <= zone_last; zt++)
1463                present_pages += pgdat->node_zones[zt].present_pages;
1464        if (nr_pages >= present_pages)
1465                arg->status_change_nid = zone_to_nid(zone);
1466        else
1467                arg->status_change_nid = -1;
1468}
1469
1470static void node_states_clear_node(int node, struct memory_notify *arg)
1471{
1472        if (arg->status_change_nid_normal >= 0)
1473                node_clear_state(node, N_NORMAL_MEMORY);
1474
1475        if ((N_MEMORY != N_NORMAL_MEMORY) &&
1476            (arg->status_change_nid_high >= 0))
1477                node_clear_state(node, N_HIGH_MEMORY);
1478
1479        if ((N_MEMORY != N_HIGH_MEMORY) &&
1480            (arg->status_change_nid >= 0))
1481                node_clear_state(node, N_MEMORY);
1482}
1483
1484static int __ref __offline_pages(unsigned long start_pfn,
1485                  unsigned long end_pfn, unsigned long timeout)
1486{
1487        unsigned long pfn, nr_pages, expire;
1488        long offlined_pages;
1489        int ret, drain, retry_max, node;
1490        struct zone *zone;
1491        struct memory_notify arg;
1492
1493        BUG_ON(start_pfn >= end_pfn);
1494        /* at least, alignment against pageblock is necessary */
1495        if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1496                return -EINVAL;
1497        if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1498                return -EINVAL;
1499        /* This makes hotplug much easier...and readable.
1500           we assume this for now. .*/
1501        if (!test_pages_in_a_zone(start_pfn, end_pfn))
1502                return -EINVAL;
1503
1504        lock_memory_hotplug();
1505
1506        zone = page_zone(pfn_to_page(start_pfn));
1507        node = zone_to_nid(zone);
1508        nr_pages = end_pfn - start_pfn;
1509
1510        ret = -EINVAL;
1511        if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1512                goto out;
1513
1514        /* set above range as isolated */
1515        ret = start_isolate_page_range(start_pfn, end_pfn,
1516                                       MIGRATE_MOVABLE, true);
1517        if (ret)
1518                goto out;
1519
1520        arg.start_pfn = start_pfn;
1521        arg.nr_pages = nr_pages;
1522        node_states_check_changes_offline(nr_pages, zone, &arg);
1523
1524        ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1525        ret = notifier_to_errno(ret);
1526        if (ret)
1527                goto failed_removal;
1528
1529        pfn = start_pfn;
1530        expire = jiffies + timeout;
1531        drain = 0;
1532        retry_max = 5;
1533repeat:
1534        /* start memory hot removal */
1535        ret = -EAGAIN;
1536        if (time_after(jiffies, expire))
1537                goto failed_removal;
1538        ret = -EINTR;
1539        if (signal_pending(current))
1540                goto failed_removal;
1541        ret = 0;
1542        if (drain) {
1543                lru_add_drain_all();
1544                cond_resched();
1545                drain_all_pages();
1546        }
1547
1548        pfn = scan_lru_pages(start_pfn, end_pfn);
1549        if (pfn) { /* We have page on LRU */
1550                ret = do_migrate_range(pfn, end_pfn);
1551                if (!ret) {
1552                        drain = 1;
1553                        goto repeat;
1554                } else {
1555                        if (ret < 0)
1556                                if (--retry_max == 0)
1557                                        goto failed_removal;
1558                        yield();
1559                        drain = 1;
1560                        goto repeat;
1561                }
1562        }
1563        /* drain all zone's lru pagevec, this is asynchronous... */
1564        lru_add_drain_all();
1565        yield();
1566        /* drain pcp pages, this is synchronous. */
1567        drain_all_pages();
1568        /* check again */
1569        offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1570        if (offlined_pages < 0) {
1571                ret = -EBUSY;
1572                goto failed_removal;
1573        }
1574        printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1575        /* Ok, all of our target is isolated.
1576           We cannot do rollback at this point. */
1577        offline_isolated_pages(start_pfn, end_pfn);
1578        /* reset pagetype flags and makes migrate type to be MOVABLE */
1579        undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1580        /* removal success */
1581        zone->managed_pages -= offlined_pages;
1582        zone->present_pages -= offlined_pages;
1583        zone->zone_pgdat->node_present_pages -= offlined_pages;
1584        totalram_pages -= offlined_pages;
1585
1586        init_per_zone_wmark_min();
1587
1588        if (!populated_zone(zone)) {
1589                zone_pcp_reset(zone);
1590                mutex_lock(&zonelists_mutex);
1591                build_all_zonelists(NULL, NULL);
1592                mutex_unlock(&zonelists_mutex);
1593        } else
1594                zone_pcp_update(zone);
1595
1596        node_states_clear_node(node, &arg);
1597        if (arg.status_change_nid >= 0)
1598                kswapd_stop(node);
1599
1600        vm_total_pages = nr_free_pagecache_pages();
1601        writeback_set_ratelimit();
1602
1603        memory_notify(MEM_OFFLINE, &arg);
1604        unlock_memory_hotplug();
1605        return 0;
1606
1607failed_removal:
1608        printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1609               (unsigned long long) start_pfn << PAGE_SHIFT,
1610               ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1611        memory_notify(MEM_CANCEL_OFFLINE, &arg);
1612        /* pushback to free area */
1613        undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1614
1615out:
1616        unlock_memory_hotplug();
1617        return ret;
1618}
1619
1620int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1621{
1622        return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1623}
1624
1625/**
1626 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1627 * @start_pfn: start pfn of the memory range
1628 * @end_pfn: end pfn of the memory range
1629 * @arg: argument passed to func
1630 * @func: callback for each memory section walked
1631 *
1632 * This function walks through all present mem sections in range
1633 * [start_pfn, end_pfn) and call func on each mem section.
1634 *
1635 * Returns the return value of func.
1636 */
1637static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1638                void *arg, int (*func)(struct memory_block *, void *))
1639{
1640        struct memory_block *mem = NULL;
1641        struct mem_section *section;
1642        unsigned long pfn, section_nr;
1643        int ret;
1644
1645        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1646                section_nr = pfn_to_section_nr(pfn);
1647                if (!present_section_nr(section_nr))
1648                        continue;
1649
1650                section = __nr_to_section(section_nr);
1651                /* same memblock? */
1652                if (mem)
1653                        if ((section_nr >= mem->start_section_nr) &&
1654                            (section_nr <= mem->end_section_nr))
1655                                continue;
1656
1657                mem = find_memory_block_hinted(section, mem);
1658                if (!mem)
1659                        continue;
1660
1661                ret = func(mem, arg);
1662                if (ret) {
1663                        kobject_put(&mem->dev.kobj);
1664                        return ret;
1665                }
1666        }
1667
1668        if (mem)
1669                kobject_put(&mem->dev.kobj);
1670
1671        return 0;
1672}
1673
1674/**
1675 * offline_memory_block_cb - callback function for offlining memory block
1676 * @mem: the memory block to be offlined
1677 * @arg: buffer to hold error msg
1678 *
1679 * Always return 0, and put the error msg in arg if any.
1680 */
1681static int offline_memory_block_cb(struct memory_block *mem, void *arg)
1682{
1683        int *ret = arg;
1684        int error = offline_memory_block(mem);
1685
1686        if (error != 0 && *ret == 0)
1687                *ret = error;
1688
1689        return 0;
1690}
1691
1692static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
1693{
1694        int ret = !is_memblock_offlined(mem);
1695
1696        if (unlikely(ret)) {
1697                phys_addr_t beginpa, endpa;
1698
1699                beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1700                endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1701                pr_warn("removing memory fails, because memory "
1702                        "[%pa-%pa] is onlined\n",
1703                        &beginpa, &endpa);
1704        }
1705
1706        return ret;
1707}
1708
1709static int check_cpu_on_node(void *data)
1710{
1711        struct pglist_data *pgdat = data;
1712        int cpu;
1713
1714        for_each_present_cpu(cpu) {
1715                if (cpu_to_node(cpu) == pgdat->node_id)
1716                        /*
1717                         * the cpu on this node isn't removed, and we can't
1718                         * offline this node.
1719                         */
1720                        return -EBUSY;
1721        }
1722
1723        return 0;
1724}
1725
1726static void unmap_cpu_on_node(void *data)
1727{
1728#ifdef CONFIG_ACPI_NUMA
1729        struct pglist_data *pgdat = data;
1730        int cpu;
1731
1732        for_each_possible_cpu(cpu)
1733                if (cpu_to_node(cpu) == pgdat->node_id)
1734                        numa_clear_node(cpu);
1735#endif
1736}
1737
1738static int check_and_unmap_cpu_on_node(void *data)
1739{
1740        int ret = check_cpu_on_node(data);
1741
1742        if (ret)
1743                return ret;
1744
1745        /*
1746         * the node will be offlined when we come here, so we can clear
1747         * the cpu_to_node() now.
1748         */
1749
1750        unmap_cpu_on_node(data);
1751        return 0;
1752}
1753
1754/* offline the node if all memory sections of this node are removed */
1755void try_offline_node(int nid)
1756{
1757        pg_data_t *pgdat = NODE_DATA(nid);
1758        unsigned long start_pfn = pgdat->node_start_pfn;
1759        unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1760        unsigned long pfn;
1761        struct page *pgdat_page = virt_to_page(pgdat);
1762        int i;
1763
1764        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1765                unsigned long section_nr = pfn_to_section_nr(pfn);
1766
1767                if (!present_section_nr(section_nr))
1768                        continue;
1769
1770                if (pfn_to_nid(pfn) != nid)
1771                        continue;
1772
1773                /*
1774                 * some memory sections of this node are not removed, and we
1775                 * can't offline node now.
1776                 */
1777                return;
1778        }
1779
1780        if (stop_machine(check_and_unmap_cpu_on_node, pgdat, NULL))
1781                return;
1782
1783        /*
1784         * all memory/cpu of this node are removed, we can offline this
1785         * node now.
1786         */
1787        node_set_offline(nid);
1788        unregister_one_node(nid);
1789
1790        if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
1791                /* node data is allocated from boot memory */
1792                return;
1793
1794        /* free waittable in each zone */
1795        for (i = 0; i < MAX_NR_ZONES; i++) {
1796                struct zone *zone = pgdat->node_zones + i;
1797
1798                /*
1799                 * wait_table may be allocated from boot memory,
1800                 * here only free if it's allocated by vmalloc.
1801                 */
1802                if (is_vmalloc_addr(zone->wait_table))
1803                        vfree(zone->wait_table);
1804        }
1805
1806        /*
1807         * Since there is no way to guarentee the address of pgdat/zone is not
1808         * on stack of any kernel threads or used by other kernel objects
1809         * without reference counting or other symchronizing method, do not
1810         * reset node_data and free pgdat here. Just reset it to 0 and reuse
1811         * the memory when the node is online again.
1812         */
1813        memset(pgdat, 0, sizeof(*pgdat));
1814}
1815EXPORT_SYMBOL(try_offline_node);
1816
1817int __ref remove_memory(int nid, u64 start, u64 size)
1818{
1819        unsigned long start_pfn, end_pfn;
1820        int ret = 0;
1821        int retry = 1;
1822
1823        start_pfn = PFN_DOWN(start);
1824        end_pfn = PFN_UP(start + size - 1);
1825
1826        /*
1827         * When CONFIG_MEMCG is on, one memory block may be used by other
1828         * blocks to store page cgroup when onlining pages. But we don't know
1829         * in what order pages are onlined. So we iterate twice to offline
1830         * memory:
1831         * 1st iterate: offline every non primary memory block.
1832         * 2nd iterate: offline primary (i.e. first added) memory block.
1833         */
1834repeat:
1835        walk_memory_range(start_pfn, end_pfn, &ret,
1836                          offline_memory_block_cb);
1837        if (ret) {
1838                if (!retry)
1839                        return ret;
1840
1841                retry = 0;
1842                ret = 0;
1843                goto repeat;
1844        }
1845
1846        lock_memory_hotplug();
1847
1848        /*
1849         * we have offlined all memory blocks like this:
1850         *   1. lock memory hotplug
1851         *   2. offline a memory block
1852         *   3. unlock memory hotplug
1853         *
1854         * repeat step1-3 to offline the memory block. All memory blocks
1855         * must be offlined before removing memory. But we don't hold the
1856         * lock in the whole operation. So we should check whether all
1857         * memory blocks are offlined.
1858         */
1859
1860        ret = walk_memory_range(start_pfn, end_pfn, NULL,
1861                                is_memblock_offlined_cb);
1862        if (ret) {
1863                unlock_memory_hotplug();
1864                return ret;
1865        }
1866
1867        /* remove memmap entry */
1868        firmware_map_remove(start, start + size, "System RAM");
1869
1870        arch_remove_memory(start, size);
1871
1872        try_offline_node(nid);
1873
1874        unlock_memory_hotplug();
1875
1876        return 0;
1877}
1878#else
1879int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1880{
1881        return -EINVAL;
1882}
1883int remove_memory(int nid, u64 start, u64 size)
1884{
1885        return -EINVAL;
1886}
1887#endif /* CONFIG_MEMORY_HOTREMOVE */
1888EXPORT_SYMBOL_GPL(remove_memory);
1889
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.