linux/mm/memory_hotplug.c
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   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
  33#include <asm/tlbflush.h>
  34
  35#include "internal.h"
  36
  37/*
  38 * online_page_callback contains pointer to current page onlining function.
  39 * Initially it is generic_online_page(). If it is required it could be
  40 * changed by calling set_online_page_callback() for callback registration
  41 * and restore_online_page_callback() for generic callback restore.
  42 */
  43
  44static void generic_online_page(struct page *page);
  45
  46static online_page_callback_t online_page_callback = generic_online_page;
  47
  48DEFINE_MUTEX(mem_hotplug_mutex);
  49
  50void lock_memory_hotplug(void)
  51{
  52        mutex_lock(&mem_hotplug_mutex);
  53
  54        /* for exclusive hibernation if CONFIG_HIBERNATION=y */
  55        lock_system_sleep();
  56}
  57
  58void unlock_memory_hotplug(void)
  59{
  60        unlock_system_sleep();
  61        mutex_unlock(&mem_hotplug_mutex);
  62}
  63
  64
  65/* add this memory to iomem resource */
  66static struct resource *register_memory_resource(u64 start, u64 size)
  67{
  68        struct resource *res;
  69        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
  70        BUG_ON(!res);
  71
  72        res->name = "System RAM";
  73        res->start = start;
  74        res->end = start + size - 1;
  75        res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  76        if (request_resource(&iomem_resource, res) < 0) {
  77                printk("System RAM resource %pR cannot be added\n", res);
  78                kfree(res);
  79                res = NULL;
  80        }
  81        return res;
  82}
  83
  84static void release_memory_resource(struct resource *res)
  85{
  86        if (!res)
  87                return;
  88        release_resource(res);
  89        kfree(res);
  90        return;
  91}
  92
  93#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
  94#ifndef CONFIG_SPARSEMEM_VMEMMAP
  95static void 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        }
 128
 129}
 130
 131static void register_page_bootmem_info_section(unsigned long start_pfn)
 132{
 133        unsigned long *usemap, mapsize, section_nr, i;
 134        struct mem_section *ms;
 135        struct page *page, *memmap;
 136
 137        section_nr = pfn_to_section_nr(start_pfn);
 138        ms = __nr_to_section(section_nr);
 139
 140        /* Get section's memmap address */
 141        memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 142
 143        /*
 144         * Get page for the memmap's phys address
 145         * XXX: need more consideration for sparse_vmemmap...
 146         */
 147        page = virt_to_page(memmap);
 148        mapsize = sizeof(struct page) * PAGES_PER_SECTION;
 149        mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
 150
 151        /* remember memmap's page */
 152        for (i = 0; i < mapsize; i++, page++)
 153                get_page_bootmem(section_nr, page, SECTION_INFO);
 154
 155        usemap = __nr_to_section(section_nr)->pageblock_flags;
 156        page = virt_to_page(usemap);
 157
 158        mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 159
 160        for (i = 0; i < mapsize; i++, page++)
 161                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 162
 163}
 164
 165void register_page_bootmem_info_node(struct pglist_data *pgdat)
 166{
 167        unsigned long i, pfn, end_pfn, nr_pages;
 168        int node = pgdat->node_id;
 169        struct page *page;
 170        struct zone *zone;
 171
 172        nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
 173        page = virt_to_page(pgdat);
 174
 175        for (i = 0; i < nr_pages; i++, page++)
 176                get_page_bootmem(node, page, NODE_INFO);
 177
 178        zone = &pgdat->node_zones[0];
 179        for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
 180                if (zone->wait_table) {
 181                        nr_pages = zone->wait_table_hash_nr_entries
 182                                * sizeof(wait_queue_head_t);
 183                        nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
 184                        page = virt_to_page(zone->wait_table);
 185
 186                        for (i = 0; i < nr_pages; i++, page++)
 187                                get_page_bootmem(node, page, NODE_INFO);
 188                }
 189        }
 190
 191        pfn = pgdat->node_start_pfn;
 192        end_pfn = pfn + pgdat->node_spanned_pages;
 193
 194        /* register_section info */
 195        for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 196                /*
 197                 * Some platforms can assign the same pfn to multiple nodes - on
 198                 * node0 as well as nodeN.  To avoid registering a pfn against
 199                 * multiple nodes we check that this pfn does not already
 200                 * reside in some other node.
 201                 */
 202                if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
 203                        register_page_bootmem_info_section(pfn);
 204        }
 205}
 206#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 207
 208static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
 209                           unsigned long end_pfn)
 210{
 211        unsigned long old_zone_end_pfn;
 212
 213        zone_span_writelock(zone);
 214
 215        old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 216        if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
 217                zone->zone_start_pfn = start_pfn;
 218
 219        zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
 220                                zone->zone_start_pfn;
 221
 222        zone_span_writeunlock(zone);
 223}
 224
 225static void resize_zone(struct zone *zone, unsigned long start_pfn,
 226                unsigned long end_pfn)
 227{
 228        zone_span_writelock(zone);
 229
 230        if (end_pfn - start_pfn) {
 231                zone->zone_start_pfn = start_pfn;
 232                zone->spanned_pages = end_pfn - start_pfn;
 233        } else {
 234                /*
 235                 * make it consist as free_area_init_core(),
 236                 * if spanned_pages = 0, then keep start_pfn = 0
 237                 */
 238                zone->zone_start_pfn = 0;
 239                zone->spanned_pages = 0;
 240        }
 241
 242        zone_span_writeunlock(zone);
 243}
 244
 245static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
 246                unsigned long end_pfn)
 247{
 248        enum zone_type zid = zone_idx(zone);
 249        int nid = zone->zone_pgdat->node_id;
 250        unsigned long pfn;
 251
 252        for (pfn = start_pfn; pfn < end_pfn; pfn++)
 253                set_page_links(pfn_to_page(pfn), zid, nid, pfn);
 254}
 255
 256static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
 257                unsigned long start_pfn, unsigned long end_pfn)
 258{
 259        int ret;
 260        unsigned long flags;
 261        unsigned long z1_start_pfn;
 262
 263        if (!z1->wait_table) {
 264                ret = init_currently_empty_zone(z1, start_pfn,
 265                        end_pfn - start_pfn, MEMMAP_HOTPLUG);
 266                if (ret)
 267                        return ret;
 268        }
 269
 270        pgdat_resize_lock(z1->zone_pgdat, &flags);
 271
 272        /* can't move pfns which are higher than @z2 */
 273        if (end_pfn > z2->zone_start_pfn + z2->spanned_pages)
 274                goto out_fail;
 275        /* the move out part mast at the left most of @z2 */
 276        if (start_pfn > z2->zone_start_pfn)
 277                goto out_fail;
 278        /* must included/overlap */
 279        if (end_pfn <= z2->zone_start_pfn)
 280                goto out_fail;
 281
 282        /* use start_pfn for z1's start_pfn if z1 is empty */
 283        if (z1->spanned_pages)
 284                z1_start_pfn = z1->zone_start_pfn;
 285        else
 286                z1_start_pfn = start_pfn;
 287
 288        resize_zone(z1, z1_start_pfn, end_pfn);
 289        resize_zone(z2, end_pfn, z2->zone_start_pfn + z2->spanned_pages);
 290
 291        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 292
 293        fix_zone_id(z1, start_pfn, end_pfn);
 294
 295        return 0;
 296out_fail:
 297        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 298        return -1;
 299}
 300
 301static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
 302                unsigned long start_pfn, unsigned long end_pfn)
 303{
 304        int ret;
 305        unsigned long flags;
 306        unsigned long z2_end_pfn;
 307
 308        if (!z2->wait_table) {
 309                ret = init_currently_empty_zone(z2, start_pfn,
 310                        end_pfn - start_pfn, MEMMAP_HOTPLUG);
 311                if (ret)
 312                        return ret;
 313        }
 314
 315        pgdat_resize_lock(z1->zone_pgdat, &flags);
 316
 317        /* can't move pfns which are lower than @z1 */
 318        if (z1->zone_start_pfn > start_pfn)
 319                goto out_fail;
 320        /* the move out part mast at the right most of @z1 */
 321        if (z1->zone_start_pfn + z1->spanned_pages >  end_pfn)
 322                goto out_fail;
 323        /* must included/overlap */
 324        if (start_pfn >= z1->zone_start_pfn + z1->spanned_pages)
 325                goto out_fail;
 326
 327        /* use end_pfn for z2's end_pfn if z2 is empty */
 328        if (z2->spanned_pages)
 329                z2_end_pfn = z2->zone_start_pfn + z2->spanned_pages;
 330        else
 331                z2_end_pfn = end_pfn;
 332
 333        resize_zone(z1, z1->zone_start_pfn, start_pfn);
 334        resize_zone(z2, start_pfn, z2_end_pfn);
 335
 336        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 337
 338        fix_zone_id(z2, start_pfn, end_pfn);
 339
 340        return 0;
 341out_fail:
 342        pgdat_resize_unlock(z1->zone_pgdat, &flags);
 343        return -1;
 344}
 345
 346static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
 347                            unsigned long end_pfn)
 348{
 349        unsigned long old_pgdat_end_pfn =
 350                pgdat->node_start_pfn + pgdat->node_spanned_pages;
 351
 352        if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
 353                pgdat->node_start_pfn = start_pfn;
 354
 355        pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
 356                                        pgdat->node_start_pfn;
 357}
 358
 359static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 360{
 361        struct pglist_data *pgdat = zone->zone_pgdat;
 362        int nr_pages = PAGES_PER_SECTION;
 363        int nid = pgdat->node_id;
 364        int zone_type;
 365        unsigned long flags;
 366
 367        zone_type = zone - pgdat->node_zones;
 368        if (!zone->wait_table) {
 369                int ret;
 370
 371                ret = init_currently_empty_zone(zone, phys_start_pfn,
 372                                                nr_pages, MEMMAP_HOTPLUG);
 373                if (ret)
 374                        return ret;
 375        }
 376        pgdat_resize_lock(zone->zone_pgdat, &flags);
 377        grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
 378        grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
 379                        phys_start_pfn + nr_pages);
 380        pgdat_resize_unlock(zone->zone_pgdat, &flags);
 381        memmap_init_zone(nr_pages, nid, zone_type,
 382                         phys_start_pfn, MEMMAP_HOTPLUG);
 383        return 0;
 384}
 385
 386static int __meminit __add_section(int nid, struct zone *zone,
 387                                        unsigned long phys_start_pfn)
 388{
 389        int nr_pages = PAGES_PER_SECTION;
 390        int ret;
 391
 392        if (pfn_valid(phys_start_pfn))
 393                return -EEXIST;
 394
 395        ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
 396
 397        if (ret < 0)
 398                return ret;
 399
 400        ret = __add_zone(zone, phys_start_pfn);
 401
 402        if (ret < 0)
 403                return ret;
 404
 405        return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 406}
 407
 408#ifdef CONFIG_SPARSEMEM_VMEMMAP
 409static int __remove_section(struct zone *zone, struct mem_section *ms)
 410{
 411        /*
 412         * XXX: Freeing memmap with vmemmap is not implement yet.
 413         *      This should be removed later.
 414         */
 415        return -EBUSY;
 416}
 417#else
 418static int __remove_section(struct zone *zone, struct mem_section *ms)
 419{
 420        unsigned long flags;
 421        struct pglist_data *pgdat = zone->zone_pgdat;
 422        int ret = -EINVAL;
 423
 424        if (!valid_section(ms))
 425                return ret;
 426
 427        ret = unregister_memory_section(ms);
 428        if (ret)
 429                return ret;
 430
 431        pgdat_resize_lock(pgdat, &flags);
 432        sparse_remove_one_section(zone, ms);
 433        pgdat_resize_unlock(pgdat, &flags);
 434        return 0;
 435}
 436#endif
 437
 438/*
 439 * Reasonably generic function for adding memory.  It is
 440 * expected that archs that support memory hotplug will
 441 * call this function after deciding the zone to which to
 442 * add the new pages.
 443 */
 444int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 445                        unsigned long nr_pages)
 446{
 447        unsigned long i;
 448        int err = 0;
 449        int start_sec, end_sec;
 450        /* during initialize mem_map, align hot-added range to section */
 451        start_sec = pfn_to_section_nr(phys_start_pfn);
 452        end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 453
 454        for (i = start_sec; i <= end_sec; i++) {
 455                err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
 456
 457                /*
 458                 * EEXIST is finally dealt with by ioresource collision
 459                 * check. see add_memory() => register_memory_resource()
 460                 * Warning will be printed if there is collision.
 461                 */
 462                if (err && (err != -EEXIST))
 463                        break;
 464                err = 0;
 465        }
 466
 467        return err;
 468}
 469EXPORT_SYMBOL_GPL(__add_pages);
 470
 471/**
 472 * __remove_pages() - remove sections of pages from a zone
 473 * @zone: zone from which pages need to be removed
 474 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
 475 * @nr_pages: number of pages to remove (must be multiple of section size)
 476 *
 477 * Generic helper function to remove section mappings and sysfs entries
 478 * for the section of the memory we are removing. Caller needs to make
 479 * sure that pages are marked reserved and zones are adjust properly by
 480 * calling offline_pages().
 481 */
 482int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 483                 unsigned long nr_pages)
 484{
 485        unsigned long i, ret = 0;
 486        int sections_to_remove;
 487
 488        /*
 489         * We can only remove entire sections
 490         */
 491        BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 492        BUG_ON(nr_pages % PAGES_PER_SECTION);
 493
 494        release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
 495
 496        sections_to_remove = nr_pages / PAGES_PER_SECTION;
 497        for (i = 0; i < sections_to_remove; i++) {
 498                unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 499                ret = __remove_section(zone, __pfn_to_section(pfn));
 500                if (ret)
 501                        break;
 502        }
 503        return ret;
 504}
 505EXPORT_SYMBOL_GPL(__remove_pages);
 506
 507int set_online_page_callback(online_page_callback_t callback)
 508{
 509        int rc = -EINVAL;
 510
 511        lock_memory_hotplug();
 512
 513        if (online_page_callback == generic_online_page) {
 514                online_page_callback = callback;
 515                rc = 0;
 516        }
 517
 518        unlock_memory_hotplug();
 519
 520        return rc;
 521}
 522EXPORT_SYMBOL_GPL(set_online_page_callback);
 523
 524int restore_online_page_callback(online_page_callback_t callback)
 525{
 526        int rc = -EINVAL;
 527
 528        lock_memory_hotplug();
 529
 530        if (online_page_callback == callback) {
 531                online_page_callback = generic_online_page;
 532                rc = 0;
 533        }
 534
 535        unlock_memory_hotplug();
 536
 537        return rc;
 538}
 539EXPORT_SYMBOL_GPL(restore_online_page_callback);
 540
 541void __online_page_set_limits(struct page *page)
 542{
 543        unsigned long pfn = page_to_pfn(page);
 544
 545        if (pfn >= num_physpages)
 546                num_physpages = pfn + 1;
 547}
 548EXPORT_SYMBOL_GPL(__online_page_set_limits);
 549
 550void __online_page_increment_counters(struct page *page)
 551{
 552        totalram_pages++;
 553
 554#ifdef CONFIG_HIGHMEM
 555        if (PageHighMem(page))
 556                totalhigh_pages++;
 557#endif
 558}
 559EXPORT_SYMBOL_GPL(__online_page_increment_counters);
 560
 561void __online_page_free(struct page *page)
 562{
 563        ClearPageReserved(page);
 564        init_page_count(page);
 565        __free_page(page);
 566}
 567EXPORT_SYMBOL_GPL(__online_page_free);
 568
 569static void generic_online_page(struct page *page)
 570{
 571        __online_page_set_limits(page);
 572        __online_page_increment_counters(page);
 573        __online_page_free(page);
 574}
 575
 576static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 577                        void *arg)
 578{
 579        unsigned long i;
 580        unsigned long onlined_pages = *(unsigned long *)arg;
 581        struct page *page;
 582        if (PageReserved(pfn_to_page(start_pfn)))
 583                for (i = 0; i < nr_pages; i++) {
 584                        page = pfn_to_page(start_pfn + i);
 585                        (*online_page_callback)(page);
 586                        onlined_pages++;
 587                }
 588        *(unsigned long *)arg = onlined_pages;
 589        return 0;
 590}
 591
 592#ifdef CONFIG_MOVABLE_NODE
 593/*
 594 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
 595 * normal memory.
 596 */
 597static bool can_online_high_movable(struct zone *zone)
 598{
 599        return true;
 600}
 601#else /* CONFIG_MOVABLE_NODE */
 602/* ensure every online node has NORMAL memory */
 603static bool can_online_high_movable(struct zone *zone)
 604{
 605        return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
 606}
 607#endif /* CONFIG_MOVABLE_NODE */
 608
 609/* check which state of node_states will be changed when online memory */
 610static void node_states_check_changes_online(unsigned long nr_pages,
 611        struct zone *zone, struct memory_notify *arg)
 612{
 613        int nid = zone_to_nid(zone);
 614        enum zone_type zone_last = ZONE_NORMAL;
 615
 616        /*
 617         * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
 618         * contains nodes which have zones of 0...ZONE_NORMAL,
 619         * set zone_last to ZONE_NORMAL.
 620         *
 621         * If we don't have HIGHMEM nor movable node,
 622         * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
 623         * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
 624         */
 625        if (N_MEMORY == N_NORMAL_MEMORY)
 626                zone_last = ZONE_MOVABLE;
 627
 628        /*
 629         * if the memory to be online is in a zone of 0...zone_last, and
 630         * the zones of 0...zone_last don't have memory before online, we will
 631         * need to set the node to node_states[N_NORMAL_MEMORY] after
 632         * the memory is online.
 633         */
 634        if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
 635                arg->status_change_nid_normal = nid;
 636        else
 637                arg->status_change_nid_normal = -1;
 638
 639#ifdef CONFIG_HIGHMEM
 640        /*
 641         * If we have movable node, node_states[N_HIGH_MEMORY]
 642         * contains nodes which have zones of 0...ZONE_HIGHMEM,
 643         * set zone_last to ZONE_HIGHMEM.
 644         *
 645         * If we don't have movable node, node_states[N_NORMAL_MEMORY]
 646         * contains nodes which have zones of 0...ZONE_MOVABLE,
 647         * set zone_last to ZONE_MOVABLE.
 648         */
 649        zone_last = ZONE_HIGHMEM;
 650        if (N_MEMORY == N_HIGH_MEMORY)
 651                zone_last = ZONE_MOVABLE;
 652
 653        if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
 654                arg->status_change_nid_high = nid;
 655        else
 656                arg->status_change_nid_high = -1;
 657#else
 658        arg->status_change_nid_high = arg->status_change_nid_normal;
 659#endif
 660
 661        /*
 662         * if the node don't have memory befor online, we will need to
 663         * set the node to node_states[N_MEMORY] after the memory
 664         * is online.
 665         */
 666        if (!node_state(nid, N_MEMORY))
 667                arg->status_change_nid = nid;
 668        else
 669                arg->status_change_nid = -1;
 670}
 671
 672static void node_states_set_node(int node, struct memory_notify *arg)
 673{
 674        if (arg->status_change_nid_normal >= 0)
 675                node_set_state(node, N_NORMAL_MEMORY);
 676
 677        if (arg->status_change_nid_high >= 0)
 678                node_set_state(node, N_HIGH_MEMORY);
 679
 680        node_set_state(node, N_MEMORY);
 681}
 682
 683
 684int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
 685{
 686        unsigned long onlined_pages = 0;
 687        struct zone *zone;
 688        int need_zonelists_rebuild = 0;
 689        int nid;
 690        int ret;
 691        struct memory_notify arg;
 692
 693        lock_memory_hotplug();
 694        /*
 695         * This doesn't need a lock to do pfn_to_page().
 696         * The section can't be removed here because of the
 697         * memory_block->state_mutex.
 698         */
 699        zone = page_zone(pfn_to_page(pfn));
 700
 701        if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
 702            !can_online_high_movable(zone)) {
 703                unlock_memory_hotplug();
 704                return -1;
 705        }
 706
 707        if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
 708                if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
 709                        unlock_memory_hotplug();
 710                        return -1;
 711                }
 712        }
 713        if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
 714                if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
 715                        unlock_memory_hotplug();
 716                        return -1;
 717                }
 718        }
 719
 720        /* Previous code may changed the zone of the pfn range */
 721        zone = page_zone(pfn_to_page(pfn));
 722
 723        arg.start_pfn = pfn;
 724        arg.nr_pages = nr_pages;
 725        node_states_check_changes_online(nr_pages, zone, &arg);
 726
 727        nid = page_to_nid(pfn_to_page(pfn));
 728
 729        ret = memory_notify(MEM_GOING_ONLINE, &arg);
 730        ret = notifier_to_errno(ret);
 731        if (ret) {
 732                memory_notify(MEM_CANCEL_ONLINE, &arg);
 733                unlock_memory_hotplug();
 734                return ret;
 735        }
 736        /*
 737         * If this zone is not populated, then it is not in zonelist.
 738         * This means the page allocator ignores this zone.
 739         * So, zonelist must be updated after online.
 740         */
 741        mutex_lock(&zonelists_mutex);
 742        if (!populated_zone(zone)) {
 743                need_zonelists_rebuild = 1;
 744                build_all_zonelists(NULL, zone);
 745        }
 746
 747        ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
 748                online_pages_range);
 749        if (ret) {
 750                if (need_zonelists_rebuild)
 751                        zone_pcp_reset(zone);
 752                mutex_unlock(&zonelists_mutex);
 753                printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
 754                       (unsigned long long) pfn << PAGE_SHIFT,
 755                       (((unsigned long long) pfn + nr_pages)
 756                            << PAGE_SHIFT) - 1);
 757                memory_notify(MEM_CANCEL_ONLINE, &arg);
 758                unlock_memory_hotplug();
 759                return ret;
 760        }
 761
 762        zone->managed_pages += onlined_pages;
 763        zone->present_pages += onlined_pages;
 764        zone->zone_pgdat->node_present_pages += onlined_pages;
 765        if (onlined_pages) {
 766                node_states_set_node(zone_to_nid(zone), &arg);
 767                if (need_zonelists_rebuild)
 768                        build_all_zonelists(NULL, NULL);
 769                else
 770                        zone_pcp_update(zone);
 771        }
 772
 773        mutex_unlock(&zonelists_mutex);
 774
 775        init_per_zone_wmark_min();
 776
 777        if (onlined_pages)
 778                kswapd_run(zone_to_nid(zone));
 779
 780        vm_total_pages = nr_free_pagecache_pages();
 781
 782        writeback_set_ratelimit();
 783
 784        if (onlined_pages)
 785                memory_notify(MEM_ONLINE, &arg);
 786        unlock_memory_hotplug();
 787
 788        return 0;
 789}
 790#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 791
 792/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
 793static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 794{
 795        struct pglist_data *pgdat;
 796        unsigned long zones_size[MAX_NR_ZONES] = {0};
 797        unsigned long zholes_size[MAX_NR_ZONES] = {0};
 798        unsigned long start_pfn = start >> PAGE_SHIFT;
 799
 800        pgdat = arch_alloc_nodedata(nid);
 801        if (!pgdat)
 802                return NULL;
 803
 804        arch_refresh_nodedata(nid, pgdat);
 805
 806        /* we can use NODE_DATA(nid) from here */
 807
 808        /* init node's zones as empty zones, we don't have any present pages.*/
 809        free_area_init_node(nid, zones_size, start_pfn, zholes_size);
 810
 811        /*
 812         * The node we allocated has no zone fallback lists. For avoiding
 813         * to access not-initialized zonelist, build here.
 814         */
 815        mutex_lock(&zonelists_mutex);
 816        build_all_zonelists(pgdat, NULL);
 817        mutex_unlock(&zonelists_mutex);
 818
 819        return pgdat;
 820}
 821
 822static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 823{
 824        arch_refresh_nodedata(nid, NULL);
 825        arch_free_nodedata(pgdat);
 826        return;
 827}
 828
 829
 830/*
 831 * called by cpu_up() to online a node without onlined memory.
 832 */
 833int mem_online_node(int nid)
 834{
 835        pg_data_t       *pgdat;
 836        int     ret;
 837
 838        lock_memory_hotplug();
 839        pgdat = hotadd_new_pgdat(nid, 0);
 840        if (!pgdat) {
 841                ret = -ENOMEM;
 842                goto out;
 843        }
 844        node_set_online(nid);
 845        ret = register_one_node(nid);
 846        BUG_ON(ret);
 847
 848out:
 849        unlock_memory_hotplug();
 850        return ret;
 851}
 852
 853/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
 854int __ref add_memory(int nid, u64 start, u64 size)
 855{
 856        pg_data_t *pgdat = NULL;
 857        int new_pgdat = 0;
 858        struct resource *res;
 859        int ret;
 860
 861        lock_memory_hotplug();
 862
 863        res = register_memory_resource(start, size);
 864        ret = -EEXIST;
 865        if (!res)
 866                goto out;
 867
 868        if (!node_online(nid)) {
 869                pgdat = hotadd_new_pgdat(nid, start);
 870                ret = -ENOMEM;
 871                if (!pgdat)
 872                        goto error;
 873                new_pgdat = 1;
 874        }
 875
 876        /* call arch's memory hotadd */
 877        ret = arch_add_memory(nid, start, size);
 878
 879        if (ret < 0)
 880                goto error;
 881
 882        /* we online node here. we can't roll back from here. */
 883        node_set_online(nid);
 884
 885        if (new_pgdat) {
 886                ret = register_one_node(nid);
 887                /*
 888                 * If sysfs file of new node can't create, cpu on the node
 889                 * can't be hot-added. There is no rollback way now.
 890                 * So, check by BUG_ON() to catch it reluctantly..
 891                 */
 892                BUG_ON(ret);
 893        }
 894
 895        /* create new memmap entry */
 896        firmware_map_add_hotplug(start, start + size, "System RAM");
 897
 898        goto out;
 899
 900error:
 901        /* rollback pgdat allocation and others */
 902        if (new_pgdat)
 903                rollback_node_hotadd(nid, pgdat);
 904        if (res)
 905                release_memory_resource(res);
 906
 907out:
 908        unlock_memory_hotplug();
 909        return ret;
 910}
 911EXPORT_SYMBOL_GPL(add_memory);
 912
 913#ifdef CONFIG_MEMORY_HOTREMOVE
 914/*
 915 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
 916 * set and the size of the free page is given by page_order(). Using this,
 917 * the function determines if the pageblock contains only free pages.
 918 * Due to buddy contraints, a free page at least the size of a pageblock will
 919 * be located at the start of the pageblock
 920 */
 921static inline int pageblock_free(struct page *page)
 922{
 923        return PageBuddy(page) && page_order(page) >= pageblock_order;
 924}
 925
 926/* Return the start of the next active pageblock after a given page */
 927static struct page *next_active_pageblock(struct page *page)
 928{
 929        /* Ensure the starting page is pageblock-aligned */
 930        BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
 931
 932        /* If the entire pageblock is free, move to the end of free page */
 933        if (pageblock_free(page)) {
 934                int order;
 935                /* be careful. we don't have locks, page_order can be changed.*/
 936                order = page_order(page);
 937                if ((order < MAX_ORDER) && (order >= pageblock_order))
 938                        return page + (1 << order);
 939        }
 940
 941        return page + pageblock_nr_pages;
 942}
 943
 944/* Checks if this range of memory is likely to be hot-removable. */
 945int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
 946{
 947        struct page *page = pfn_to_page(start_pfn);
 948        struct page *end_page = page + nr_pages;
 949
 950        /* Check the starting page of each pageblock within the range */
 951        for (; page < end_page; page = next_active_pageblock(page)) {
 952                if (!is_pageblock_removable_nolock(page))
 953                        return 0;
 954                cond_resched();
 955        }
 956
 957        /* All pageblocks in the memory block are likely to be hot-removable */
 958        return 1;
 959}
 960
 961/*
 962 * Confirm all pages in a range [start, end) is belongs to the same zone.
 963 */
 964static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
 965{
 966        unsigned long pfn;
 967        struct zone *zone = NULL;
 968        struct page *page;
 969        int i;
 970        for (pfn = start_pfn;
 971             pfn < end_pfn;
 972             pfn += MAX_ORDER_NR_PAGES) {
 973                i = 0;
 974                /* This is just a CONFIG_HOLES_IN_ZONE check.*/
 975                while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
 976                        i++;
 977                if (i == MAX_ORDER_NR_PAGES)
 978                        continue;
 979                page = pfn_to_page(pfn + i);
 980                if (zone && page_zone(page) != zone)
 981                        return 0;
 982                zone = page_zone(page);
 983        }
 984        return 1;
 985}
 986
 987/*
 988 * Scanning pfn is much easier than scanning lru list.
 989 * Scan pfn from start to end and Find LRU page.
 990 */
 991static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
 992{
 993        unsigned long pfn;
 994        struct page *page;
 995        for (pfn = start; pfn < end; pfn++) {
 996                if (pfn_valid(pfn)) {
 997                        page = pfn_to_page(pfn);
 998                        if (PageLRU(page))
 999                                return pfn;
1000                }
1001        }
1002        return 0;
1003}
1004
1005#define NR_OFFLINE_AT_ONCE_PAGES        (256)
1006static int
1007do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1008{
1009        unsigned long pfn;
1010        struct page *page;
1011        int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1012        int not_managed = 0;
1013        int ret = 0;
1014        LIST_HEAD(source);
1015
1016        for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1017                if (!pfn_valid(pfn))
1018                        continue;
1019                page = pfn_to_page(pfn);
1020                if (!get_page_unless_zero(page))
1021                        continue;
1022                /*
1023                 * We can skip free pages. And we can only deal with pages on
1024                 * LRU.
1025                 */
1026                ret = isolate_lru_page(page);
1027                if (!ret) { /* Success */
1028                        put_page(page);
1029                        list_add_tail(&page->lru, &source);
1030                        move_pages--;
1031                        inc_zone_page_state(page, NR_ISOLATED_ANON +
1032                                            page_is_file_cache(page));
1033
1034                } else {
1035#ifdef CONFIG_DEBUG_VM
1036                        printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
1037                               pfn);
1038                        dump_page(page);
1039#endif
1040                        put_page(page);
1041                        /* Because we don't have big zone->lock. we should
1042                           check this again here. */
1043                        if (page_count(page)) {
1044                                not_managed++;
1045                                ret = -EBUSY;
1046                                break;
1047                        }
1048                }
1049        }
1050        if (!list_empty(&source)) {
1051                if (not_managed) {
1052                        putback_lru_pages(&source);
1053                        goto out;
1054                }
1055
1056                /*
1057                 * alloc_migrate_target should be improooooved!!
1058                 * migrate_pages returns # of failed pages.
1059                 */
1060                ret = migrate_pages(&source, alloc_migrate_target, 0,
1061                                                        true, MIGRATE_SYNC,
1062                                                        MR_MEMORY_HOTPLUG);
1063                if (ret)
1064                        putback_lru_pages(&source);
1065        }
1066out:
1067        return ret;
1068}
1069
1070/*
1071 * remove from free_area[] and mark all as Reserved.
1072 */
1073static int
1074offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1075                        void *data)
1076{
1077        __offline_isolated_pages(start, start + nr_pages);
1078        return 0;
1079}
1080
1081static void
1082offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1083{
1084        walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1085                                offline_isolated_pages_cb);
1086}
1087
1088/*
1089 * Check all pages in range, recoreded as memory resource, are isolated.
1090 */
1091static int
1092check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1093                        void *data)
1094{
1095        int ret;
1096        long offlined = *(long *)data;
1097        ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1098        offlined = nr_pages;
1099        if (!ret)
1100                *(long *)data += offlined;
1101        return ret;
1102}
1103
1104static long
1105check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1106{
1107        long offlined = 0;
1108        int ret;
1109
1110        ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1111                        check_pages_isolated_cb);
1112        if (ret < 0)
1113                offlined = (long)ret;
1114        return offlined;
1115}
1116
1117#ifdef CONFIG_MOVABLE_NODE
1118/*
1119 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1120 * normal memory.
1121 */
1122static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1123{
1124        return true;
1125}
1126#else /* CONFIG_MOVABLE_NODE */
1127/* ensure the node has NORMAL memory if it is still online */
1128static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1129{
1130        struct pglist_data *pgdat = zone->zone_pgdat;
1131        unsigned long present_pages = 0;
1132        enum zone_type zt;
1133
1134        for (zt = 0; zt <= ZONE_NORMAL; zt++)
1135                present_pages += pgdat->node_zones[zt].present_pages;
1136
1137        if (present_pages > nr_pages)
1138                return true;
1139
1140        present_pages = 0;
1141        for (; zt <= ZONE_MOVABLE; zt++)
1142                present_pages += pgdat->node_zones[zt].present_pages;
1143
1144        /*
1145         * we can't offline the last normal memory until all
1146         * higher memory is offlined.
1147         */
1148        return present_pages == 0;
1149}
1150#endif /* CONFIG_MOVABLE_NODE */
1151
1152/* check which state of node_states will be changed when offline memory */
1153static void node_states_check_changes_offline(unsigned long nr_pages,
1154                struct zone *zone, struct memory_notify *arg)
1155{
1156        struct pglist_data *pgdat = zone->zone_pgdat;
1157        unsigned long present_pages = 0;
1158        enum zone_type zt, zone_last = ZONE_NORMAL;
1159
1160        /*
1161         * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1162         * contains nodes which have zones of 0...ZONE_NORMAL,
1163         * set zone_last to ZONE_NORMAL.
1164         *
1165         * If we don't have HIGHMEM nor movable node,
1166         * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1167         * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1168         */
1169        if (N_MEMORY == N_NORMAL_MEMORY)
1170                zone_last = ZONE_MOVABLE;
1171
1172        /*
1173         * check whether node_states[N_NORMAL_MEMORY] will be changed.
1174         * If the memory to be offline is in a zone of 0...zone_last,
1175         * and it is the last present memory, 0...zone_last will
1176         * become empty after offline , thus we can determind we will
1177         * need to clear the node from node_states[N_NORMAL_MEMORY].
1178         */
1179        for (zt = 0; zt <= zone_last; zt++)
1180                present_pages += pgdat->node_zones[zt].present_pages;
1181        if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1182                arg->status_change_nid_normal = zone_to_nid(zone);
1183        else
1184                arg->status_change_nid_normal = -1;
1185
1186#ifdef CONFIG_HIGHMEM
1187        /*
1188         * If we have movable node, node_states[N_HIGH_MEMORY]
1189         * contains nodes which have zones of 0...ZONE_HIGHMEM,
1190         * set zone_last to ZONE_HIGHMEM.
1191         *
1192         * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1193         * contains nodes which have zones of 0...ZONE_MOVABLE,
1194         * set zone_last to ZONE_MOVABLE.
1195         */
1196        zone_last = ZONE_HIGHMEM;
1197        if (N_MEMORY == N_HIGH_MEMORY)
1198                zone_last = ZONE_MOVABLE;
1199
1200        for (; zt <= zone_last; zt++)
1201                present_pages += pgdat->node_zones[zt].present_pages;
1202        if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1203                arg->status_change_nid_high = zone_to_nid(zone);
1204        else
1205                arg->status_change_nid_high = -1;
1206#else
1207        arg->status_change_nid_high = arg->status_change_nid_normal;
1208#endif
1209
1210        /*
1211         * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1212         */
1213        zone_last = ZONE_MOVABLE;
1214
1215        /*
1216         * check whether node_states[N_HIGH_MEMORY] will be changed
1217         * If we try to offline the last present @nr_pages from the node,
1218         * we can determind we will need to clear the node from
1219         * node_states[N_HIGH_MEMORY].
1220         */
1221        for (; zt <= zone_last; zt++)
1222                present_pages += pgdat->node_zones[zt].present_pages;
1223        if (nr_pages >= present_pages)
1224                arg->status_change_nid = zone_to_nid(zone);
1225        else
1226                arg->status_change_nid = -1;
1227}
1228
1229static void node_states_clear_node(int node, struct memory_notify *arg)
1230{
1231        if (arg->status_change_nid_normal >= 0)
1232                node_clear_state(node, N_NORMAL_MEMORY);
1233
1234        if ((N_MEMORY != N_NORMAL_MEMORY) &&
1235            (arg->status_change_nid_high >= 0))
1236                node_clear_state(node, N_HIGH_MEMORY);
1237
1238        if ((N_MEMORY != N_HIGH_MEMORY) &&
1239            (arg->status_change_nid >= 0))
1240                node_clear_state(node, N_MEMORY);
1241}
1242
1243static int __ref __offline_pages(unsigned long start_pfn,
1244                  unsigned long end_pfn, unsigned long timeout)
1245{
1246        unsigned long pfn, nr_pages, expire;
1247        long offlined_pages;
1248        int ret, drain, retry_max, node;
1249        struct zone *zone;
1250        struct memory_notify arg;
1251
1252        BUG_ON(start_pfn >= end_pfn);
1253        /* at least, alignment against pageblock is necessary */
1254        if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1255                return -EINVAL;
1256        if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1257                return -EINVAL;
1258        /* This makes hotplug much easier...and readable.
1259           we assume this for now. .*/
1260        if (!test_pages_in_a_zone(start_pfn, end_pfn))
1261                return -EINVAL;
1262
1263        lock_memory_hotplug();
1264
1265        zone = page_zone(pfn_to_page(start_pfn));
1266        node = zone_to_nid(zone);
1267        nr_pages = end_pfn - start_pfn;
1268
1269        ret = -EINVAL;
1270        if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1271                goto out;
1272
1273        /* set above range as isolated */
1274        ret = start_isolate_page_range(start_pfn, end_pfn,
1275                                       MIGRATE_MOVABLE, true);
1276        if (ret)
1277                goto out;
1278
1279        arg.start_pfn = start_pfn;
1280        arg.nr_pages = nr_pages;
1281        node_states_check_changes_offline(nr_pages, zone, &arg);
1282
1283        ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1284        ret = notifier_to_errno(ret);
1285        if (ret)
1286                goto failed_removal;
1287
1288        pfn = start_pfn;
1289        expire = jiffies + timeout;
1290        drain = 0;
1291        retry_max = 5;
1292repeat:
1293        /* start memory hot removal */
1294        ret = -EAGAIN;
1295        if (time_after(jiffies, expire))
1296                goto failed_removal;
1297        ret = -EINTR;
1298        if (signal_pending(current))
1299                goto failed_removal;
1300        ret = 0;
1301        if (drain) {
1302                lru_add_drain_all();
1303                cond_resched();
1304                drain_all_pages();
1305        }
1306
1307        pfn = scan_lru_pages(start_pfn, end_pfn);
1308        if (pfn) { /* We have page on LRU */
1309                ret = do_migrate_range(pfn, end_pfn);
1310                if (!ret) {
1311                        drain = 1;
1312                        goto repeat;
1313                } else {
1314                        if (ret < 0)
1315                                if (--retry_max == 0)
1316                                        goto failed_removal;
1317                        yield();
1318                        drain = 1;
1319                        goto repeat;
1320                }
1321        }
1322        /* drain all zone's lru pagevec, this is asynchronous... */
1323        lru_add_drain_all();
1324        yield();
1325        /* drain pcp pages, this is synchronous. */
1326        drain_all_pages();
1327        /* check again */
1328        offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1329        if (offlined_pages < 0) {
1330                ret = -EBUSY;
1331                goto failed_removal;
1332        }
1333        printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1334        /* Ok, all of our target is isolated.
1335           We cannot do rollback at this point. */
1336        offline_isolated_pages(start_pfn, end_pfn);
1337        /* reset pagetype flags and makes migrate type to be MOVABLE */
1338        undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1339        /* removal success */
1340        zone->managed_pages -= offlined_pages;
1341        zone->present_pages -= offlined_pages;
1342        zone->zone_pgdat->node_present_pages -= offlined_pages;
1343        totalram_pages -= offlined_pages;
1344
1345        init_per_zone_wmark_min();
1346
1347        if (!populated_zone(zone)) {
1348                zone_pcp_reset(zone);
1349                mutex_lock(&zonelists_mutex);
1350                build_all_zonelists(NULL, NULL);
1351                mutex_unlock(&zonelists_mutex);
1352        } else
1353                zone_pcp_update(zone);
1354
1355        node_states_clear_node(node, &arg);
1356        if (arg.status_change_nid >= 0)
1357                kswapd_stop(node);
1358
1359        vm_total_pages = nr_free_pagecache_pages();
1360        writeback_set_ratelimit();
1361
1362        memory_notify(MEM_OFFLINE, &arg);
1363        unlock_memory_hotplug();
1364        return 0;
1365
1366failed_removal:
1367        printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1368               (unsigned long long) start_pfn << PAGE_SHIFT,
1369               ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1370        memory_notify(MEM_CANCEL_OFFLINE, &arg);
1371        /* pushback to free area */
1372        undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1373
1374out:
1375        unlock_memory_hotplug();
1376        return ret;
1377}
1378
1379int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1380{
1381        return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1382}
1383
1384int remove_memory(u64 start, u64 size)
1385{
1386        struct memory_block *mem = NULL;
1387        struct mem_section *section;
1388        unsigned long start_pfn, end_pfn;
1389        unsigned long pfn, section_nr;
1390        int ret;
1391
1392        start_pfn = PFN_DOWN(start);
1393        end_pfn = start_pfn + PFN_DOWN(size);
1394
1395        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1396                section_nr = pfn_to_section_nr(pfn);
1397                if (!present_section_nr(section_nr))
1398                        continue;
1399
1400                section = __nr_to_section(section_nr);
1401                /* same memblock? */
1402                if (mem)
1403                        if ((section_nr >= mem->start_section_nr) &&
1404                            (section_nr <= mem->end_section_nr))
1405                                continue;
1406
1407                mem = find_memory_block_hinted(section, mem);
1408                if (!mem)
1409                        continue;
1410
1411                ret = offline_memory_block(mem);
1412                if (ret) {
1413                        kobject_put(&mem->dev.kobj);
1414                        return ret;
1415                }
1416        }
1417
1418        if (mem)
1419                kobject_put(&mem->dev.kobj);
1420
1421        return 0;
1422}
1423#else
1424int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1425{
1426        return -EINVAL;
1427}
1428int remove_memory(u64 start, u64 size)
1429{
1430        return -EINVAL;
1431}
1432#endif /* CONFIG_MEMORY_HOTREMOVE */
1433EXPORT_SYMBOL_GPL(remove_memory);
1434
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