mm/memory_hotplug.c

   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
  45 static void generic_online_page(struct page *page);
  46
  47 static online_page_callback_t online_page_callback = generic_online_page;
  48
  49 DEFINE_MUTEX(mem_hotplug_mutex);
  50
  51 void 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
  59 void 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 */
  67 static 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
  85 static 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
  95 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 */
 106 void __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
 134 static 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 */
 168 static 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
 194 void 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
 237 static 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
 254 static 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
 274 static 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() */
 287 static 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
 296 static 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;
 333 out_fail:
 334         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 335         return -1;
 336 }
 337
 338 static 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;
 375 out_fail:
 376         pgdat_resize_unlock(z1->zone_pgdat, &flags);
 377         return -1;
 378 }
 379
 380 static 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
 393 static 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
 417 static 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  */
 445 int __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 }
 470 EXPORT_SYMBOL_GPL(__add_pages);
 471
 472 #ifdef CONFIG_MEMORY_HOTREMOVE
 473 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
 474 static 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). */
 499 static 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
 526 static 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
 593 static 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
 659 static 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
 674 static 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  */
 706 int __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 }
 739 EXPORT_SYMBOL_GPL(__remove_pages);
 740 #endif /* CONFIG_MEMORY_HOTREMOVE */
 741
 742 int 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 }
 757 EXPORT_SYMBOL_GPL(set_online_page_callback);
 758
 759 int 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 }
 774 EXPORT_SYMBOL_GPL(restore_online_page_callback);
 775
 776 void __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 }
 783 EXPORT_SYMBOL_GPL(__online_page_set_limits);
 784
 785 void __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 }
 794 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
 795
 796 void __online_page_free(struct page *page)
 797 {
 798         ClearPageReserved(page);
 799         init_page_count(page);
 800         __free_page(page);
 801 }
 802 EXPORT_SYMBOL_GPL(__online_page_free);
 803
 804 static 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
 811 static 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  */
 832 static 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 */
 838 static 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 */
 845 static 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
 907 static 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
 919 int __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 */
1028 static 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
1060 static 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  */
1071 int 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
1086 out:
1087         unlock_memory_hotplug();
1088         return ret;
1089 }
1090
1091 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1092 int __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
1143 error:
1144         /* rollback pgdat allocation and others */
1145         if (new_pgdat)
1146                 rollback_node_hotadd(nid, pgdat);
1147         release_memory_resource(res);
1148
1149 out:
1150         unlock_memory_hotplug();
1151         return ret;
1152 }
1153 EXPORT_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  */
1163 static 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 */
1169 static 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. */
1187 int 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  */
1206 static 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  */
1233 static 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)
1248 static int
1249 do_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         }
1307 out:
1308         return ret;
1309 }
1310
1311 /*
1312  * remove from free_area[] and mark all as Reserved.
1313  */
1314 static int
1315 offline_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
1322 static void
1323 offline_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  */
1332 static int
1333 check_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
1345 static long
1346 check_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  */
1363 static 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 */
1369 static 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 */
1394 static 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
1470 static 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
1484 static 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;
1533 repeat:
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
1607 failed_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
1615 out:
1616         unlock_memory_hotplug();
1617         return ret;
1618 }
1619
1620 int 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  */
1637 static 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  */
1681 static 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
1692 static 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
1709 static 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
1726 static 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
1738 static 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 */
1755 void 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 }
1815 EXPORT_SYMBOL(try_offline_node);
1816
1817 int __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          */
1834 repeat:
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
1879 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1880 {
1881         return -EINVAL;
1882 }
1883 int remove_memory(int nid, u64 start, u64 size)
1884 {
1885         return -EINVAL;
1886 }
1887 #endif /* CONFIG_MEMORY_HOTREMOVE */
1888 EXPORT_SYMBOL_GPL(remove_memory);