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/cpuset.h> 26 #include <linux/delay.h> 27 #include <linux/migrate.h> 28 #include <linux/page-isolation.h> 29 30 #include <asm/tlbflush.h> 31 32 /* add this memory to iomem resource */ 33 static struct resource *register_memory_resource(u64 start, u64 size) 34 { 35 struct resource *res; 36 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 37 BUG_ON(!res); 38 39 res->name = "System RAM"; 40 res->start = start; 41 res->end = start + size - 1; 42 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 43 if (request_resource(&iomem_resource, res) < 0) { 44 printk("System RAM resource %llx - %llx cannot be added\n", 45 (unsigned long long)res->start, (unsigned long long)res->end); 46 kfree(res); 47 res = NULL; 48 } 49 return res; 50 } 51 52 static void release_memory_resource(struct resource *res) 53 { 54 if (!res) 55 return; 56 release_resource(res); 57 kfree(res); 58 return; 59 } 60 61 62 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 63 static int __add_zone(struct zone *zone, unsigned long phys_start_pfn) 64 { 65 struct pglist_data *pgdat = zone->zone_pgdat; 66 int nr_pages = PAGES_PER_SECTION; 67 int nid = pgdat->node_id; 68 int zone_type; 69 70 zone_type = zone - pgdat->node_zones; 71 if (!zone->wait_table) { 72 int ret = 0; 73 ret = init_currently_empty_zone(zone, phys_start_pfn, 74 nr_pages, MEMMAP_HOTPLUG); 75 if (ret < 0) 76 return ret; 77 } 78 memmap_init_zone(nr_pages, nid, zone_type, 79 phys_start_pfn, MEMMAP_HOTPLUG); 80 return 0; 81 } 82 83 static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 84 { 85 int nr_pages = PAGES_PER_SECTION; 86 int ret; 87 88 if (pfn_valid(phys_start_pfn)) 89 return -EEXIST; 90 91 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 92 93 if (ret < 0) 94 return ret; 95 96 ret = __add_zone(zone, phys_start_pfn); 97 98 if (ret < 0) 99 return ret; 100 101 return register_new_memory(__pfn_to_section(phys_start_pfn)); 102 } 103 104 /* 105 * Reasonably generic function for adding memory. It is 106 * expected that archs that support memory hotplug will 107 * call this function after deciding the zone to which to 108 * add the new pages. 109 */ 110 int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 111 unsigned long nr_pages) 112 { 113 unsigned long i; 114 int err = 0; 115 int start_sec, end_sec; 116 /* during initialize mem_map, align hot-added range to section */ 117 start_sec = pfn_to_section_nr(phys_start_pfn); 118 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 119 120 for (i = start_sec; i <= end_sec; i++) { 121 err = __add_section(zone, i << PFN_SECTION_SHIFT); 122 123 /* 124 * EEXIST is finally dealt with by ioresource collision 125 * check. see add_memory() => register_memory_resource() 126 * Warning will be printed if there is collision. 127 */ 128 if (err && (err != -EEXIST)) 129 break; 130 err = 0; 131 } 132 133 return err; 134 } 135 EXPORT_SYMBOL_GPL(__add_pages); 136 137 static void grow_zone_span(struct zone *zone, 138 unsigned long start_pfn, unsigned long end_pfn) 139 { 140 unsigned long old_zone_end_pfn; 141 142 zone_span_writelock(zone); 143 144 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 145 if (start_pfn < zone->zone_start_pfn) 146 zone->zone_start_pfn = start_pfn; 147 148 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 149 zone->zone_start_pfn; 150 151 zone_span_writeunlock(zone); 152 } 153 154 static void grow_pgdat_span(struct pglist_data *pgdat, 155 unsigned long start_pfn, unsigned long end_pfn) 156 { 157 unsigned long old_pgdat_end_pfn = 158 pgdat->node_start_pfn + pgdat->node_spanned_pages; 159 160 if (start_pfn < pgdat->node_start_pfn) 161 pgdat->node_start_pfn = start_pfn; 162 163 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 164 pgdat->node_start_pfn; 165 } 166 167 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 168 void *arg) 169 { 170 unsigned long i; 171 unsigned long onlined_pages = *(unsigned long *)arg; 172 struct page *page; 173 if (PageReserved(pfn_to_page(start_pfn))) 174 for (i = 0; i < nr_pages; i++) { 175 page = pfn_to_page(start_pfn + i); 176 online_page(page); 177 onlined_pages++; 178 } 179 *(unsigned long *)arg = onlined_pages; 180 return 0; 181 } 182 183 184 int online_pages(unsigned long pfn, unsigned long nr_pages) 185 { 186 unsigned long flags; 187 unsigned long onlined_pages = 0; 188 struct zone *zone; 189 int need_zonelists_rebuild = 0; 190 int nid; 191 int ret; 192 struct memory_notify arg; 193 194 arg.start_pfn = pfn; 195 arg.nr_pages = nr_pages; 196 arg.status_change_nid = -1; 197 198 nid = page_to_nid(pfn_to_page(pfn)); 199 if (node_present_pages(nid) == 0) 200 arg.status_change_nid = nid; 201 202 ret = memory_notify(MEM_GOING_ONLINE, &arg); 203 ret = notifier_to_errno(ret); 204 if (ret) { 205 memory_notify(MEM_CANCEL_ONLINE, &arg); 206 return ret; 207 } 208 /* 209 * This doesn't need a lock to do pfn_to_page(). 210 * The section can't be removed here because of the 211 * memory_block->state_sem. 212 */ 213 zone = page_zone(pfn_to_page(pfn)); 214 pgdat_resize_lock(zone->zone_pgdat, &flags); 215 grow_zone_span(zone, pfn, pfn + nr_pages); 216 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); 217 pgdat_resize_unlock(zone->zone_pgdat, &flags); 218 219 /* 220 * If this zone is not populated, then it is not in zonelist. 221 * This means the page allocator ignores this zone. 222 * So, zonelist must be updated after online. 223 */ 224 if (!populated_zone(zone)) 225 need_zonelists_rebuild = 1; 226 227 walk_memory_resource(pfn, nr_pages, &onlined_pages, 228 online_pages_range); 229 zone->present_pages += onlined_pages; 230 zone->zone_pgdat->node_present_pages += onlined_pages; 231 232 setup_per_zone_pages_min(); 233 if (onlined_pages) { 234 kswapd_run(zone_to_nid(zone)); 235 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 236 } 237 238 if (need_zonelists_rebuild) 239 build_all_zonelists(); 240 vm_total_pages = nr_free_pagecache_pages(); 241 writeback_set_ratelimit(); 242 243 if (onlined_pages) 244 memory_notify(MEM_ONLINE, &arg); 245 246 return 0; 247 } 248 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 249 250 static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 251 { 252 struct pglist_data *pgdat; 253 unsigned long zones_size[MAX_NR_ZONES] = {0}; 254 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 255 unsigned long start_pfn = start >> PAGE_SHIFT; 256 257 pgdat = arch_alloc_nodedata(nid); 258 if (!pgdat) 259 return NULL; 260 261 arch_refresh_nodedata(nid, pgdat); 262 263 /* we can use NODE_DATA(nid) from here */ 264 265 /* init node's zones as empty zones, we don't have any present pages.*/ 266 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 267 268 return pgdat; 269 } 270 271 static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 272 { 273 arch_refresh_nodedata(nid, NULL); 274 arch_free_nodedata(pgdat); 275 return; 276 } 277 278 279 int add_memory(int nid, u64 start, u64 size) 280 { 281 pg_data_t *pgdat = NULL; 282 int new_pgdat = 0; 283 struct resource *res; 284 int ret; 285 286 res = register_memory_resource(start, size); 287 if (!res) 288 return -EEXIST; 289 290 if (!node_online(nid)) { 291 pgdat = hotadd_new_pgdat(nid, start); 292 if (!pgdat) 293 return -ENOMEM; 294 new_pgdat = 1; 295 } 296 297 /* call arch's memory hotadd */ 298 ret = arch_add_memory(nid, start, size); 299 300 if (ret < 0) 301 goto error; 302 303 /* we online node here. we can't roll back from here. */ 304 node_set_online(nid); 305 306 cpuset_track_online_nodes(); 307 308 if (new_pgdat) { 309 ret = register_one_node(nid); 310 /* 311 * If sysfs file of new node can't create, cpu on the node 312 * can't be hot-added. There is no rollback way now. 313 * So, check by BUG_ON() to catch it reluctantly.. 314 */ 315 BUG_ON(ret); 316 } 317 318 return ret; 319 error: 320 /* rollback pgdat allocation and others */ 321 if (new_pgdat) 322 rollback_node_hotadd(nid, pgdat); 323 if (res) 324 release_memory_resource(res); 325 326 return ret; 327 } 328 EXPORT_SYMBOL_GPL(add_memory); 329 330 #ifdef CONFIG_MEMORY_HOTREMOVE 331 /* 332 * Confirm all pages in a range [start, end) is belongs to the same zone. 333 */ 334 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 335 { 336 unsigned long pfn; 337 struct zone *zone = NULL; 338 struct page *page; 339 int i; 340 for (pfn = start_pfn; 341 pfn < end_pfn; 342 pfn += MAX_ORDER_NR_PAGES) { 343 i = 0; 344 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 345 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 346 i++; 347 if (i == MAX_ORDER_NR_PAGES) 348 continue; 349 page = pfn_to_page(pfn + i); 350 if (zone && page_zone(page) != zone) 351 return 0; 352 zone = page_zone(page); 353 } 354 return 1; 355 } 356 357 /* 358 * Scanning pfn is much easier than scanning lru list. 359 * Scan pfn from start to end and Find LRU page. 360 */ 361 int scan_lru_pages(unsigned long start, unsigned long end) 362 { 363 unsigned long pfn; 364 struct page *page; 365 for (pfn = start; pfn < end; pfn++) { 366 if (pfn_valid(pfn)) { 367 page = pfn_to_page(pfn); 368 if (PageLRU(page)) 369 return pfn; 370 } 371 } 372 return 0; 373 } 374 375 static struct page * 376 hotremove_migrate_alloc(struct page *page, 377 unsigned long private, 378 int **x) 379 { 380 /* This should be improoooooved!! */ 381 return alloc_page(GFP_HIGHUSER_PAGECACHE); 382 } 383 384 385 #define NR_OFFLINE_AT_ONCE_PAGES (256) 386 static int 387 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 388 { 389 unsigned long pfn; 390 struct page *page; 391 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 392 int not_managed = 0; 393 int ret = 0; 394 LIST_HEAD(source); 395 396 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 397 if (!pfn_valid(pfn)) 398 continue; 399 page = pfn_to_page(pfn); 400 if (!page_count(page)) 401 continue; 402 /* 403 * We can skip free pages. And we can only deal with pages on 404 * LRU. 405 */ 406 ret = isolate_lru_page(page, &source); 407 if (!ret) { /* Success */ 408 move_pages--; 409 } else { 410 /* Becasue we don't have big zone->lock. we should 411 check this again here. */ 412 if (page_count(page)) 413 not_managed++; 414 #ifdef CONFIG_DEBUG_VM 415 printk(KERN_INFO "removing from LRU failed" 416 " %lx/%d/%lx\n", 417 pfn, page_count(page), page->flags); 418 #endif 419 } 420 } 421 ret = -EBUSY; 422 if (not_managed) { 423 if (!list_empty(&source)) 424 putback_lru_pages(&source); 425 goto out; 426 } 427 ret = 0; 428 if (list_empty(&source)) 429 goto out; 430 /* this function returns # of failed pages */ 431 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 432 433 out: 434 return ret; 435 } 436 437 /* 438 * remove from free_area[] and mark all as Reserved. 439 */ 440 static int 441 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 442 void *data) 443 { 444 __offline_isolated_pages(start, start + nr_pages); 445 return 0; 446 } 447 448 static void 449 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 450 { 451 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 452 offline_isolated_pages_cb); 453 } 454 455 /* 456 * Check all pages in range, recoreded as memory resource, are isolated. 457 */ 458 static int 459 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 460 void *data) 461 { 462 int ret; 463 long offlined = *(long *)data; 464 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 465 offlined = nr_pages; 466 if (!ret) 467 *(long *)data += offlined; 468 return ret; 469 } 470 471 static long 472 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 473 { 474 long offlined = 0; 475 int ret; 476 477 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 478 check_pages_isolated_cb); 479 if (ret < 0) 480 offlined = (long)ret; 481 return offlined; 482 } 483 484 extern void drain_all_local_pages(void); 485 486 int offline_pages(unsigned long start_pfn, 487 unsigned long end_pfn, unsigned long timeout) 488 { 489 unsigned long pfn, nr_pages, expire; 490 long offlined_pages; 491 int ret, drain, retry_max, node; 492 struct zone *zone; 493 struct memory_notify arg; 494 495 BUG_ON(start_pfn >= end_pfn); 496 /* at least, alignment against pageblock is necessary */ 497 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 498 return -EINVAL; 499 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 500 return -EINVAL; 501 /* This makes hotplug much easier...and readable. 502 we assume this for now. .*/ 503 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 504 return -EINVAL; 505 506 zone = page_zone(pfn_to_page(start_pfn)); 507 node = zone_to_nid(zone); 508 nr_pages = end_pfn - start_pfn; 509 510 /* set above range as isolated */ 511 ret = start_isolate_page_range(start_pfn, end_pfn); 512 if (ret) 513 return ret; 514 515 arg.start_pfn = start_pfn; 516 arg.nr_pages = nr_pages; 517 arg.status_change_nid = -1; 518 if (nr_pages >= node_present_pages(node)) 519 arg.status_change_nid = node; 520 521 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 522 ret = notifier_to_errno(ret); 523 if (ret) 524 goto failed_removal; 525 526 pfn = start_pfn; 527 expire = jiffies + timeout; 528 drain = 0; 529 retry_max = 5; 530 repeat: 531 /* start memory hot removal */ 532 ret = -EAGAIN; 533 if (time_after(jiffies, expire)) 534 goto failed_removal; 535 ret = -EINTR; 536 if (signal_pending(current)) 537 goto failed_removal; 538 ret = 0; 539 if (drain) { 540 lru_add_drain_all(); 541 flush_scheduled_work(); 542 cond_resched(); 543 drain_all_local_pages(); 544 } 545 546 pfn = scan_lru_pages(start_pfn, end_pfn); 547 if (pfn) { /* We have page on LRU */ 548 ret = do_migrate_range(pfn, end_pfn); 549 if (!ret) { 550 drain = 1; 551 goto repeat; 552 } else { 553 if (ret < 0) 554 if (--retry_max == 0) 555 goto failed_removal; 556 yield(); 557 drain = 1; 558 goto repeat; 559 } 560 } 561 /* drain all zone's lru pagevec, this is asyncronous... */ 562 lru_add_drain_all(); 563 flush_scheduled_work(); 564 yield(); 565 /* drain pcp pages , this is synchrouns. */ 566 drain_all_local_pages(); 567 /* check again */ 568 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 569 if (offlined_pages < 0) { 570 ret = -EBUSY; 571 goto failed_removal; 572 } 573 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 574 /* Ok, all of our target is islaoted. 575 We cannot do rollback at this point. */ 576 offline_isolated_pages(start_pfn, end_pfn); 577 /* reset pagetype flags and makes migrate type to be MOVABLE */ 578 undo_isolate_page_range(start_pfn, end_pfn); 579 /* removal success */ 580 zone->present_pages -= offlined_pages; 581 zone->zone_pgdat->node_present_pages -= offlined_pages; 582 totalram_pages -= offlined_pages; 583 num_physpages -= offlined_pages; 584 585 vm_total_pages = nr_free_pagecache_pages(); 586 writeback_set_ratelimit(); 587 588 memory_notify(MEM_OFFLINE, &arg); 589 return 0; 590 591 failed_removal: 592 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 593 start_pfn, end_pfn); 594 memory_notify(MEM_CANCEL_OFFLINE, &arg); 595 /* pushback to free area */ 596 undo_isolate_page_range(start_pfn, end_pfn); 597 598 return ret; 599 } 600 #else 601 int remove_memory(u64 start, u64 size) 602 { 603 return -EINVAL; 604 } 605 EXPORT_SYMBOL_GPL(remove_memory); 606 #endif /* CONFIG_MEMORY_HOTREMOVE */ 607