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/module.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
  32 #include <asm/tlbflush.h>
  33
  34 #include "internal.h"
  35
  36 /* add this memory to iomem resource */
  37 static struct resource *register_memory_resource(u64 start, u64 size)
  38 {
  39         struct resource *res;
  40         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
  41         BUG_ON(!res);
  42
  43         res->name = "System RAM";
  44         res->start = start;
  45         res->end = start + size - 1;
  46         res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  47         if (request_resource(&iomem_resource, res) < 0) {
  48                 printk("System RAM resource %llx - %llx cannot be added\n",
  49                 (unsigned long long)res->start, (unsigned long long)res->end);
  50                 kfree(res);
  51                 res = NULL;
  52         }
  53         return res;
  54 }
  55
  56 static void release_memory_resource(struct resource *res)
  57 {
  58         if (!res)
  59                 return;
  60         release_resource(res);
  61         kfree(res);
  62         return;
  63 }
  64
  65 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
  66 #ifndef CONFIG_SPARSEMEM_VMEMMAP
  67 static void get_page_bootmem(unsigned long info,  struct page *page, int type)
  68 {
  69         atomic_set(&page->_mapcount, type);
  70         SetPagePrivate(page);
  71         set_page_private(page, info);
  72         atomic_inc(&page->_count);
  73 }
  74
  75 void put_page_bootmem(struct page *page)
  76 {
  77         int type;
  78
  79         type = atomic_read(&page->_mapcount);
  80         BUG_ON(type >= -1);
  81
  82         if (atomic_dec_return(&page->_count) == 1) {
  83                 ClearPagePrivate(page);
  84                 set_page_private(page, 0);
  85                 reset_page_mapcount(page);
  86                 __free_pages_bootmem(page, 0);
  87         }
  88
  89 }
  90
  91 static void register_page_bootmem_info_section(unsigned long start_pfn)
  92 {
  93         unsigned long *usemap, mapsize, section_nr, i;
  94         struct mem_section *ms;
  95         struct page *page, *memmap;
  96
  97         if (!pfn_valid(start_pfn))
  98                 return;
  99
 100         section_nr = pfn_to_section_nr(start_pfn);
 101         ms = __nr_to_section(section_nr);
 102
 103         /* Get section's memmap address */
 104         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 105
 106         /*
 107          * Get page for the memmap's phys address
 108          * XXX: need more consideration for sparse_vmemmap...
 109          */
 110         page = virt_to_page(memmap);
 111         mapsize = sizeof(struct page) * PAGES_PER_SECTION;
 112         mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
 113
 114         /* remember memmap's page */
 115         for (i = 0; i < mapsize; i++, page++)
 116                 get_page_bootmem(section_nr, page, SECTION_INFO);
 117
 118         usemap = __nr_to_section(section_nr)->pageblock_flags;
 119         page = virt_to_page(usemap);
 120
 121         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 122
 123         for (i = 0; i < mapsize; i++, page++)
 124                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 125
 126 }
 127
 128 void register_page_bootmem_info_node(struct pglist_data *pgdat)
 129 {
 130         unsigned long i, pfn, end_pfn, nr_pages;
 131         int node = pgdat->node_id;
 132         struct page *page;
 133         struct zone *zone;
 134
 135         nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
 136         page = virt_to_page(pgdat);
 137
 138         for (i = 0; i < nr_pages; i++, page++)
 139                 get_page_bootmem(node, page, NODE_INFO);
 140
 141         zone = &pgdat->node_zones[0];
 142         for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
 143                 if (zone->wait_table) {
 144                         nr_pages = zone->wait_table_hash_nr_entries
 145                                 * sizeof(wait_queue_head_t);
 146                         nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
 147                         page = virt_to_page(zone->wait_table);
 148
 149                         for (i = 0; i < nr_pages; i++, page++)
 150                                 get_page_bootmem(node, page, NODE_INFO);
 151                 }
 152         }
 153
 154         pfn = pgdat->node_start_pfn;
 155         end_pfn = pfn + pgdat->node_spanned_pages;
 156
 157         /* register_section info */
 158         for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
 159                 register_page_bootmem_info_section(pfn);
 160
 161 }
 162 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 163
 164 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
 165                            unsigned long end_pfn)
 166 {
 167         unsigned long old_zone_end_pfn;
 168
 169         zone_span_writelock(zone);
 170
 171         old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 172         if (start_pfn < zone->zone_start_pfn)
 173                 zone->zone_start_pfn = start_pfn;
 174
 175         zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
 176                                 zone->zone_start_pfn;
 177
 178         zone_span_writeunlock(zone);
 179 }
 180
 181 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
 182                             unsigned long end_pfn)
 183 {
 184         unsigned long old_pgdat_end_pfn =
 185                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
 186
 187         if (start_pfn < pgdat->node_start_pfn)
 188                 pgdat->node_start_pfn = start_pfn;
 189
 190         pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
 191                                         pgdat->node_start_pfn;
 192 }
 193
 194 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 195 {
 196         struct pglist_data *pgdat = zone->zone_pgdat;
 197         int nr_pages = PAGES_PER_SECTION;
 198         int nid = pgdat->node_id;
 199         int zone_type;
 200         unsigned long flags;
 201
 202         zone_type = zone - pgdat->node_zones;
 203         if (!zone->wait_table) {
 204                 int ret;
 205
 206                 ret = init_currently_empty_zone(zone, phys_start_pfn,
 207                                                 nr_pages, MEMMAP_HOTPLUG);
 208                 if (ret)
 209                         return ret;
 210         }
 211         pgdat_resize_lock(zone->zone_pgdat, &flags);
 212         grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
 213         grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
 214                         phys_start_pfn + nr_pages);
 215         pgdat_resize_unlock(zone->zone_pgdat, &flags);
 216         memmap_init_zone(nr_pages, nid, zone_type,
 217                          phys_start_pfn, MEMMAP_HOTPLUG);
 218         return 0;
 219 }
 220
 221 static int __meminit __add_section(int nid, struct zone *zone,
 222                                         unsigned long phys_start_pfn)
 223 {
 224         int nr_pages = PAGES_PER_SECTION;
 225         int ret;
 226
 227         if (pfn_valid(phys_start_pfn))
 228                 return -EEXIST;
 229
 230         ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
 231
 232         if (ret < 0)
 233                 return ret;
 234
 235         ret = __add_zone(zone, phys_start_pfn);
 236
 237         if (ret < 0)
 238                 return ret;
 239
 240         return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 241 }
 242
 243 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 244 static int __remove_section(struct zone *zone, struct mem_section *ms)
 245 {
 246         /*
 247          * XXX: Freeing memmap with vmemmap is not implement yet.
 248          *      This should be removed later.
 249          */
 250         return -EBUSY;
 251 }
 252 #else
 253 static int __remove_section(struct zone *zone, struct mem_section *ms)
 254 {
 255         unsigned long flags;
 256         struct pglist_data *pgdat = zone->zone_pgdat;
 257         int ret = -EINVAL;
 258
 259         if (!valid_section(ms))
 260                 return ret;
 261
 262         ret = unregister_memory_section(ms);
 263         if (ret)
 264                 return ret;
 265
 266         pgdat_resize_lock(pgdat, &flags);
 267         sparse_remove_one_section(zone, ms);
 268         pgdat_resize_unlock(pgdat, &flags);
 269         return 0;
 270 }
 271 #endif
 272
 273 /*
 274  * Reasonably generic function for adding memory.  It is
 275  * expected that archs that support memory hotplug will
 276  * call this function after deciding the zone to which to
 277  * add the new pages.
 278  */
 279 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 280                         unsigned long nr_pages)
 281 {
 282         unsigned long i;
 283         int err = 0;
 284         int start_sec, end_sec;
 285         /* during initialize mem_map, align hot-added range to section */
 286         start_sec = pfn_to_section_nr(phys_start_pfn);
 287         end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 288
 289         for (i = start_sec; i <= end_sec; i++) {
 290                 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
 291
 292                 /*
 293                  * EEXIST is finally dealt with by ioresource collision
 294                  * check. see add_memory() => register_memory_resource()
 295                  * Warning will be printed if there is collision.
 296                  */
 297                 if (err && (err != -EEXIST))
 298                         break;
 299                 err = 0;
 300         }
 301
 302         return err;
 303 }
 304 EXPORT_SYMBOL_GPL(__add_pages);
 305
 306 /**
 307  * __remove_pages() - remove sections of pages from a zone
 308  * @zone: zone from which pages need to be removed
 309  * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
 310  * @nr_pages: number of pages to remove (must be multiple of section size)
 311  *
 312  * Generic helper function to remove section mappings and sysfs entries
 313  * for the section of the memory we are removing. Caller needs to make
 314  * sure that pages are marked reserved and zones are adjust properly by
 315  * calling offline_pages().
 316  */
 317 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 318                  unsigned long nr_pages)
 319 {
 320         unsigned long i, ret = 0;
 321         int sections_to_remove;
 322
 323         /*
 324          * We can only remove entire sections
 325          */
 326         BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 327         BUG_ON(nr_pages % PAGES_PER_SECTION);
 328
 329         sections_to_remove = nr_pages / PAGES_PER_SECTION;
 330         for (i = 0; i < sections_to_remove; i++) {
 331                 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 332                 release_mem_region(pfn << PAGE_SHIFT,
 333                                    PAGES_PER_SECTION << PAGE_SHIFT);
 334                 ret = __remove_section(zone, __pfn_to_section(pfn));
 335                 if (ret)
 336                         break;
 337         }
 338         return ret;
 339 }
 340 EXPORT_SYMBOL_GPL(__remove_pages);
 341
 342 void online_page(struct page *page)
 343 {
 344         unsigned long pfn = page_to_pfn(page);
 345
 346         totalram_pages++;
 347         if (pfn >= num_physpages)
 348                 num_physpages = pfn + 1;
 349
 350 #ifdef CONFIG_HIGHMEM
 351         if (PageHighMem(page))
 352                 totalhigh_pages++;
 353 #endif
 354
 355 #ifdef CONFIG_FLATMEM
 356         max_mapnr = max(page_to_pfn(page), max_mapnr);
 357 #endif
 358
 359         ClearPageReserved(page);
 360         init_page_count(page);
 361         __free_page(page);
 362 }
 363
 364 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 365                         void *arg)
 366 {
 367         unsigned long i;
 368         unsigned long onlined_pages = *(unsigned long *)arg;
 369         struct page *page;
 370         if (PageReserved(pfn_to_page(start_pfn)))
 371                 for (i = 0; i < nr_pages; i++) {
 372                         page = pfn_to_page(start_pfn + i);
 373                         online_page(page);
 374                         onlined_pages++;
 375                 }
 376         *(unsigned long *)arg = onlined_pages;
 377         return 0;
 378 }
 379
 380
 381 int online_pages(unsigned long pfn, unsigned long nr_pages)
 382 {
 383         unsigned long onlined_pages = 0;
 384         struct zone *zone;
 385         int need_zonelists_rebuild = 0;
 386         int nid;
 387         int ret;
 388         struct memory_notify arg;
 389
 390         arg.start_pfn = pfn;
 391         arg.nr_pages = nr_pages;
 392         arg.status_change_nid = -1;
 393
 394         nid = page_to_nid(pfn_to_page(pfn));
 395         if (node_present_pages(nid) == 0)
 396                 arg.status_change_nid = nid;
 397
 398         ret = memory_notify(MEM_GOING_ONLINE, &arg);
 399         ret = notifier_to_errno(ret);
 400         if (ret) {
 401                 memory_notify(MEM_CANCEL_ONLINE, &arg);
 402                 return ret;
 403         }
 404         /*
 405          * This doesn't need a lock to do pfn_to_page().
 406          * The section can't be removed here because of the
 407          * memory_block->state_mutex.
 408          */
 409         zone = page_zone(pfn_to_page(pfn));
 410         /*
 411          * If this zone is not populated, then it is not in zonelist.
 412          * This means the page allocator ignores this zone.
 413          * So, zonelist must be updated after online.
 414          */
 415         if (!populated_zone(zone))
 416                 need_zonelists_rebuild = 1;
 417
 418         ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
 419                 online_pages_range);
 420         if (ret) {
 421                 printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
 422                         nr_pages, pfn);
 423                 memory_notify(MEM_CANCEL_ONLINE, &arg);
 424                 return ret;
 425         }
 426
 427         zone->present_pages += onlined_pages;
 428         zone->zone_pgdat->node_present_pages += onlined_pages;
 429
 430         zone_pcp_update(zone);
 431         setup_per_zone_wmarks();
 432         calculate_zone_inactive_ratio(zone);
 433         if (onlined_pages) {
 434                 kswapd_run(zone_to_nid(zone));
 435                 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
 436         }
 437
 438         if (need_zonelists_rebuild)
 439                 build_all_zonelists();
 440         else
 441                 vm_total_pages = nr_free_pagecache_pages();
 442
 443         writeback_set_ratelimit();
 444
 445         if (onlined_pages)
 446                 memory_notify(MEM_ONLINE, &arg);
 447
 448         return 0;
 449 }
 450 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 451
 452 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
 453 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 454 {
 455         struct pglist_data *pgdat;
 456         unsigned long zones_size[MAX_NR_ZONES] = {0};
 457         unsigned long zholes_size[MAX_NR_ZONES] = {0};
 458         unsigned long start_pfn = start >> PAGE_SHIFT;
 459
 460         pgdat = arch_alloc_nodedata(nid);
 461         if (!pgdat)
 462                 return NULL;
 463
 464         arch_refresh_nodedata(nid, pgdat);
 465
 466         /* we can use NODE_DATA(nid) from here */
 467
 468         /* init node's zones as empty zones, we don't have any present pages.*/
 469         free_area_init_node(nid, zones_size, start_pfn, zholes_size);
 470
 471         return pgdat;
 472 }
 473
 474 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 475 {
 476         arch_refresh_nodedata(nid, NULL);
 477         arch_free_nodedata(pgdat);
 478         return;
 479 }
 480
 481
 482 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
 483 int __ref add_memory(int nid, u64 start, u64 size)
 484 {
 485         pg_data_t *pgdat = NULL;
 486         int new_pgdat = 0;
 487         struct resource *res;
 488         int ret;
 489
 490         lock_system_sleep();
 491
 492         res = register_memory_resource(start, size);
 493         ret = -EEXIST;
 494         if (!res)
 495                 goto out;
 496
 497         if (!node_online(nid)) {
 498                 pgdat = hotadd_new_pgdat(nid, start);
 499                 ret = -ENOMEM;
 500                 if (!pgdat)
 501                         goto out;
 502                 new_pgdat = 1;
 503         }
 504
 505         /* call arch's memory hotadd */
 506         ret = arch_add_memory(nid, start, size);
 507
 508         if (ret < 0)
 509                 goto error;
 510
 511         /* we online node here. we can't roll back from here. */
 512         node_set_online(nid);
 513
 514         if (new_pgdat) {
 515                 ret = register_one_node(nid);
 516                 /*
 517                  * If sysfs file of new node can't create, cpu on the node
 518                  * can't be hot-added. There is no rollback way now.
 519                  * So, check by BUG_ON() to catch it reluctantly..
 520                  */
 521                 BUG_ON(ret);
 522         }
 523
 524         goto out;
 525
 526 error:
 527         /* rollback pgdat allocation and others */
 528         if (new_pgdat)
 529                 rollback_node_hotadd(nid, pgdat);
 530         if (res)
 531                 release_memory_resource(res);
 532
 533 out:
 534         unlock_system_sleep();
 535         return ret;
 536 }
 537 EXPORT_SYMBOL_GPL(add_memory);
 538
 539 #ifdef CONFIG_MEMORY_HOTREMOVE
 540 /*
 541  * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
 542  * set and the size of the free page is given by page_order(). Using this,
 543  * the function determines if the pageblock contains only free pages.
 544  * Due to buddy contraints, a free page at least the size of a pageblock will
 545  * be located at the start of the pageblock
 546  */
 547 static inline int pageblock_free(struct page *page)
 548 {
 549         return PageBuddy(page) && page_order(page) >= pageblock_order;
 550 }
 551
 552 /* Return the start of the next active pageblock after a given page */
 553 static struct page *next_active_pageblock(struct page *page)
 554 {
 555         int pageblocks_stride;
 556
 557         /* Ensure the starting page is pageblock-aligned */
 558         BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
 559
 560         /* Move forward by at least 1 * pageblock_nr_pages */
 561         pageblocks_stride = 1;
 562
 563         /* If the entire pageblock is free, move to the end of free page */
 564         if (pageblock_free(page))
 565                 pageblocks_stride += page_order(page) - pageblock_order;
 566
 567         return page + (pageblocks_stride * pageblock_nr_pages);
 568 }
 569
 570 /* Checks if this range of memory is likely to be hot-removable. */
 571 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
 572 {
 573         int type;
 574         struct page *page = pfn_to_page(start_pfn);
 575         struct page *end_page = page + nr_pages;
 576
 577         /* Check the starting page of each pageblock within the range */
 578         for (; page < end_page; page = next_active_pageblock(page)) {
 579                 type = get_pageblock_migratetype(page);
 580
 581                 /*
 582                  * A pageblock containing MOVABLE or free pages is considered
 583                  * removable
 584                  */
 585                 if (type != MIGRATE_MOVABLE && !pageblock_free(page))
 586                         return 0;
 587
 588                 /*
 589                  * A pageblock starting with a PageReserved page is not
 590                  * considered removable.
 591                  */
 592                 if (PageReserved(page))
 593                         return 0;
 594         }
 595
 596         /* All pageblocks in the memory block are likely to be hot-removable */
 597         return 1;
 598 }
 599
 600 /*
 601  * Confirm all pages in a range [start, end) is belongs to the same zone.
 602  */
 603 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
 604 {
 605         unsigned long pfn;
 606         struct zone *zone = NULL;
 607         struct page *page;
 608         int i;
 609         for (pfn = start_pfn;
 610              pfn < end_pfn;
 611              pfn += MAX_ORDER_NR_PAGES) {
 612                 i = 0;
 613                 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
 614                 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
 615                         i++;
 616                 if (i == MAX_ORDER_NR_PAGES)
 617                         continue;
 618                 page = pfn_to_page(pfn + i);
 619                 if (zone && page_zone(page) != zone)
 620                         return 0;
 621                 zone = page_zone(page);
 622         }
 623         return 1;
 624 }
 625
 626 /*
 627  * Scanning pfn is much easier than scanning lru list.
 628  * Scan pfn from start to end and Find LRU page.
 629  */
 630 int scan_lru_pages(unsigned long start, unsigned long end)
 631 {
 632         unsigned long pfn;
 633         struct page *page;
 634         for (pfn = start; pfn < end; pfn++) {
 635                 if (pfn_valid(pfn)) {
 636                         page = pfn_to_page(pfn);
 637                         if (PageLRU(page))
 638                                 return pfn;
 639                 }
 640         }
 641         return 0;
 642 }
 643
 644 static struct page *
 645 hotremove_migrate_alloc(struct page *page, unsigned long private, int **x)
 646 {
 647         /* This should be improooooved!! */
 648         return alloc_page(GFP_HIGHUSER_MOVABLE);
 649 }
 650
 651 #define NR_OFFLINE_AT_ONCE_PAGES        (256)
 652 static int
 653 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 654 {
 655         unsigned long pfn;
 656         struct page *page;
 657         int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
 658         int not_managed = 0;
 659         int ret = 0;
 660         LIST_HEAD(source);
 661
 662         for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
 663                 if (!pfn_valid(pfn))
 664                         continue;
 665                 page = pfn_to_page(pfn);
 666                 if (!page_count(page))
 667                         continue;
 668                 /*
 669                  * We can skip free pages. And we can only deal with pages on
 670                  * LRU.
 671                  */
 672                 ret = isolate_lru_page(page);
 673                 if (!ret) { /* Success */
 674                         list_add_tail(&page->lru, &source);
 675                         move_pages--;
 676                         inc_zone_page_state(page, NR_ISOLATED_ANON +
 677                                             page_is_file_cache(page));
 678
 679                 } else {
 680                         /* Becasue we don't have big zone->lock. we should
 681                            check this again here. */
 682                         if (page_count(page))
 683                                 not_managed++;
 684 #ifdef CONFIG_DEBUG_VM
 685                         printk(KERN_INFO "removing from LRU failed"
 686                                          " %lx/%d/%lx\n",
 687                                 pfn, page_count(page), page->flags);
 688 #endif
 689                 }
 690         }
 691         ret = -EBUSY;
 692         if (not_managed) {
 693                 if (!list_empty(&source))
 694                         putback_lru_pages(&source);
 695                 goto out;
 696         }
 697         ret = 0;
 698         if (list_empty(&source))
 699                 goto out;
 700         /* this function returns # of failed pages */
 701         ret = migrate_pages(&source, hotremove_migrate_alloc, 0, 1);
 702
 703 out:
 704         return ret;
 705 }
 706
 707 /*
 708  * remove from free_area[] and mark all as Reserved.
 709  */
 710 static int
 711 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
 712                         void *data)
 713 {
 714         __offline_isolated_pages(start, start + nr_pages);
 715         return 0;
 716 }
 717
 718 static void
 719 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 720 {
 721         walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
 722                                 offline_isolated_pages_cb);
 723 }
 724
 725 /*
 726  * Check all pages in range, recoreded as memory resource, are isolated.
 727  */
 728 static int
 729 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
 730                         void *data)
 731 {
 732         int ret;
 733         long offlined = *(long *)data;
 734         ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
 735         offlined = nr_pages;
 736         if (!ret)
 737                 *(long *)data += offlined;
 738         return ret;
 739 }
 740
 741 static long
 742 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
 743 {
 744         long offlined = 0;
 745         int ret;
 746
 747         ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
 748                         check_pages_isolated_cb);
 749         if (ret < 0)
 750                 offlined = (long)ret;
 751         return offlined;
 752 }
 753
 754 int offline_pages(unsigned long start_pfn,
 755                   unsigned long end_pfn, unsigned long timeout)
 756 {
 757         unsigned long pfn, nr_pages, expire;
 758         long offlined_pages;
 759         int ret, drain, retry_max, node;
 760         struct zone *zone;
 761         struct memory_notify arg;
 762
 763         BUG_ON(start_pfn >= end_pfn);
 764         /* at least, alignment against pageblock is necessary */
 765         if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
 766                 return -EINVAL;
 767         if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
 768                 return -EINVAL;
 769         /* This makes hotplug much easier...and readable.
 770            we assume this for now. .*/
 771         if (!test_pages_in_a_zone(start_pfn, end_pfn))
 772                 return -EINVAL;
 773
 774         lock_system_sleep();
 775
 776         zone = page_zone(pfn_to_page(start_pfn));
 777         node = zone_to_nid(zone);
 778         nr_pages = end_pfn - start_pfn;
 779
 780         /* set above range as isolated */
 781         ret = start_isolate_page_range(start_pfn, end_pfn);
 782         if (ret)
 783                 goto out;
 784
 785         arg.start_pfn = start_pfn;
 786         arg.nr_pages = nr_pages;
 787         arg.status_change_nid = -1;
 788         if (nr_pages >= node_present_pages(node))
 789                 arg.status_change_nid = node;
 790
 791         ret = memory_notify(MEM_GOING_OFFLINE, &arg);
 792         ret = notifier_to_errno(ret);
 793         if (ret)
 794                 goto failed_removal;
 795
 796         pfn = start_pfn;
 797         expire = jiffies + timeout;
 798         drain = 0;
 799         retry_max = 5;
 800 repeat:
 801         /* start memory hot removal */
 802         ret = -EAGAIN;
 803         if (time_after(jiffies, expire))
 804                 goto failed_removal;
 805         ret = -EINTR;
 806         if (signal_pending(current))
 807                 goto failed_removal;
 808         ret = 0;
 809         if (drain) {
 810                 lru_add_drain_all();
 811                 flush_scheduled_work();
 812                 cond_resched();
 813                 drain_all_pages();
 814         }
 815
 816         pfn = scan_lru_pages(start_pfn, end_pfn);
 817         if (pfn) { /* We have page on LRU */
 818                 ret = do_migrate_range(pfn, end_pfn);
 819                 if (!ret) {
 820                         drain = 1;
 821                         goto repeat;
 822                 } else {
 823                         if (ret < 0)
 824                                 if (--retry_max == 0)
 825                                         goto failed_removal;
 826                         yield();
 827                         drain = 1;
 828                         goto repeat;
 829                 }
 830         }
 831         /* drain all zone's lru pagevec, this is asyncronous... */
 832         lru_add_drain_all();
 833         flush_scheduled_work();
 834         yield();
 835         /* drain pcp pages , this is synchrouns. */
 836         drain_all_pages();
 837         /* check again */
 838         offlined_pages = check_pages_isolated(start_pfn, end_pfn);
 839         if (offlined_pages < 0) {
 840                 ret = -EBUSY;
 841                 goto failed_removal;
 842         }
 843         printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
 844         /* Ok, all of our target is islaoted.
 845            We cannot do rollback at this point. */
 846         offline_isolated_pages(start_pfn, end_pfn);
 847         /* reset pagetype flags and makes migrate type to be MOVABLE */
 848         undo_isolate_page_range(start_pfn, end_pfn);
 849         /* removal success */
 850         zone->present_pages -= offlined_pages;
 851         zone->zone_pgdat->node_present_pages -= offlined_pages;
 852         totalram_pages -= offlined_pages;
 853
 854         setup_per_zone_wmarks();
 855         calculate_zone_inactive_ratio(zone);
 856         if (!node_present_pages(node)) {
 857                 node_clear_state(node, N_HIGH_MEMORY);
 858                 kswapd_stop(node);
 859         }
 860
 861         vm_total_pages = nr_free_pagecache_pages();
 862         writeback_set_ratelimit();
 863
 864         memory_notify(MEM_OFFLINE, &arg);
 865         unlock_system_sleep();
 866         return 0;
 867
 868 failed_removal:
 869         printk(KERN_INFO "memory offlining %lx to %lx failed\n",
 870                 start_pfn, end_pfn);
 871         memory_notify(MEM_CANCEL_OFFLINE, &arg);
 872         /* pushback to free area */
 873         undo_isolate_page_range(start_pfn, end_pfn);
 874
 875 out:
 876         unlock_system_sleep();
 877         return ret;
 878 }
 879
 880 int remove_memory(u64 start, u64 size)
 881 {
 882         unsigned long start_pfn, end_pfn;
 883
 884         start_pfn = PFN_DOWN(start);
 885         end_pfn = start_pfn + PFN_DOWN(size);
 886         return offline_pages(start_pfn, end_pfn, 120 * HZ);
 887 }
 888 #else
 889 int remove_memory(u64 start, u64 size)
 890 {
 891         return -EINVAL;
 892 }
 893 #endif /* CONFIG_MEMORY_HOTREMOVE */
 894 EXPORT_SYMBOL_GPL(remove_memory);