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; 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 dealed 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; 190 191 /* 192 * This doesn't need a lock to do pfn_to_page(). 193 * The section can't be removed here because of the 194 * memory_block->state_sem. 195 */ 196 zone = page_zone(pfn_to_page(pfn)); 197 pgdat_resize_lock(zone->zone_pgdat, &flags); 198 grow_zone_span(zone, pfn, pfn + nr_pages); 199 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); 200 pgdat_resize_unlock(zone->zone_pgdat, &flags); 201 202 /* 203 * If this zone is not populated, then it is not in zonelist. 204 * This means the page allocator ignores this zone. 205 * So, zonelist must be updated after online. 206 */ 207 if (!populated_zone(zone)) 208 need_zonelists_rebuild = 1; 209 210 walk_memory_resource(pfn, nr_pages, &onlined_pages, 211 online_pages_range); 212 zone->present_pages += onlined_pages; 213 zone->zone_pgdat->node_present_pages += onlined_pages; 214 215 setup_per_zone_pages_min(); 216 if (onlined_pages) { 217 kswapd_run(zone_to_nid(zone)); 218 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 219 } 220 221 if (need_zonelists_rebuild) 222 build_all_zonelists(); 223 vm_total_pages = nr_free_pagecache_pages(); 224 writeback_set_ratelimit(); 225 return 0; 226 } 227 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 228 229 static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 230 { 231 struct pglist_data *pgdat; 232 unsigned long zones_size[MAX_NR_ZONES] = {0}; 233 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 234 unsigned long start_pfn = start >> PAGE_SHIFT; 235 236 pgdat = arch_alloc_nodedata(nid); 237 if (!pgdat) 238 return NULL; 239 240 arch_refresh_nodedata(nid, pgdat); 241 242 /* we can use NODE_DATA(nid) from here */ 243 244 /* init node's zones as empty zones, we don't have any present pages.*/ 245 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 246 247 return pgdat; 248 } 249 250 static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 251 { 252 arch_refresh_nodedata(nid, NULL); 253 arch_free_nodedata(pgdat); 254 return; 255 } 256 257 258 int add_memory(int nid, u64 start, u64 size) 259 { 260 pg_data_t *pgdat = NULL; 261 int new_pgdat = 0; 262 struct resource *res; 263 int ret; 264 265 res = register_memory_resource(start, size); 266 if (!res) 267 return -EEXIST; 268 269 if (!node_online(nid)) { 270 pgdat = hotadd_new_pgdat(nid, start); 271 if (!pgdat) 272 return -ENOMEM; 273 new_pgdat = 1; 274 } 275 276 /* call arch's memory hotadd */ 277 ret = arch_add_memory(nid, start, size); 278 279 if (ret < 0) 280 goto error; 281 282 /* we online node here. we can't roll back from here. */ 283 node_set_online(nid); 284 285 cpuset_track_online_nodes(); 286 287 if (new_pgdat) { 288 ret = register_one_node(nid); 289 /* 290 * If sysfs file of new node can't create, cpu on the node 291 * can't be hot-added. There is no rollback way now. 292 * So, check by BUG_ON() to catch it reluctantly.. 293 */ 294 BUG_ON(ret); 295 } 296 297 return ret; 298 error: 299 /* rollback pgdat allocation and others */ 300 if (new_pgdat) 301 rollback_node_hotadd(nid, pgdat); 302 if (res) 303 release_memory_resource(res); 304 305 return ret; 306 } 307 EXPORT_SYMBOL_GPL(add_memory); 308 309 #ifdef CONFIG_MEMORY_HOTREMOVE 310 /* 311 * Confirm all pages in a range [start, end) is belongs to the same zone. 312 */ 313 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 314 { 315 unsigned long pfn; 316 struct zone *zone = NULL; 317 struct page *page; 318 int i; 319 for (pfn = start_pfn; 320 pfn < end_pfn; 321 pfn += MAX_ORDER_NR_PAGES) { 322 i = 0; 323 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 324 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 325 i++; 326 if (i == MAX_ORDER_NR_PAGES) 327 continue; 328 page = pfn_to_page(pfn + i); 329 if (zone && page_zone(page) != zone) 330 return 0; 331 zone = page_zone(page); 332 } 333 return 1; 334 } 335 336 /* 337 * Scanning pfn is much easier than scanning lru list. 338 * Scan pfn from start to end and Find LRU page. 339 */ 340 int scan_lru_pages(unsigned long start, unsigned long end) 341 { 342 unsigned long pfn; 343 struct page *page; 344 for (pfn = start; pfn < end; pfn++) { 345 if (pfn_valid(pfn)) { 346 page = pfn_to_page(pfn); 347 if (PageLRU(page)) 348 return pfn; 349 } 350 } 351 return 0; 352 } 353 354 static struct page * 355 hotremove_migrate_alloc(struct page *page, 356 unsigned long private, 357 int **x) 358 { 359 /* This should be improoooooved!! */ 360 return alloc_page(GFP_HIGHUSER_PAGECACHE); 361 } 362 363 364 #define NR_OFFLINE_AT_ONCE_PAGES (256) 365 static int 366 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 367 { 368 unsigned long pfn; 369 struct page *page; 370 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 371 int not_managed = 0; 372 int ret = 0; 373 LIST_HEAD(source); 374 375 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 376 if (!pfn_valid(pfn)) 377 continue; 378 page = pfn_to_page(pfn); 379 if (!page_count(page)) 380 continue; 381 /* 382 * We can skip free pages. And we can only deal with pages on 383 * LRU. 384 */ 385 ret = isolate_lru_page(page, &source); 386 if (!ret) { /* Success */ 387 move_pages--; 388 } else { 389 /* Becasue we don't have big zone->lock. we should 390 check this again here. */ 391 if (page_count(page)) 392 not_managed++; 393 #ifdef CONFIG_DEBUG_VM 394 printk(KERN_INFO "removing from LRU failed" 395 " %lx/%d/%lx\n", 396 pfn, page_count(page), page->flags); 397 #endif 398 } 399 } 400 ret = -EBUSY; 401 if (not_managed) { 402 if (!list_empty(&source)) 403 putback_lru_pages(&source); 404 goto out; 405 } 406 ret = 0; 407 if (list_empty(&source)) 408 goto out; 409 /* this function returns # of failed pages */ 410 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 411 412 out: 413 return ret; 414 } 415 416 /* 417 * remove from free_area[] and mark all as Reserved. 418 */ 419 static int 420 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 421 void *data) 422 { 423 __offline_isolated_pages(start, start + nr_pages); 424 return 0; 425 } 426 427 static void 428 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 429 { 430 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 431 offline_isolated_pages_cb); 432 } 433 434 /* 435 * Check all pages in range, recoreded as memory resource, are isolated. 436 */ 437 static int 438 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 439 void *data) 440 { 441 int ret; 442 long offlined = *(long *)data; 443 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 444 offlined = nr_pages; 445 if (!ret) 446 *(long *)data += offlined; 447 return ret; 448 } 449 450 static long 451 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 452 { 453 long offlined = 0; 454 int ret; 455 456 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 457 check_pages_isolated_cb); 458 if (ret < 0) 459 offlined = (long)ret; 460 return offlined; 461 } 462 463 extern void drain_all_local_pages(void); 464 465 int offline_pages(unsigned long start_pfn, 466 unsigned long end_pfn, unsigned long timeout) 467 { 468 unsigned long pfn, nr_pages, expire; 469 long offlined_pages; 470 int ret, drain, retry_max; 471 struct zone *zone; 472 473 BUG_ON(start_pfn >= end_pfn); 474 /* at least, alignment against pageblock is necessary */ 475 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 476 return -EINVAL; 477 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 478 return -EINVAL; 479 /* This makes hotplug much easier...and readable. 480 we assume this for now. .*/ 481 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 482 return -EINVAL; 483 /* set above range as isolated */ 484 ret = start_isolate_page_range(start_pfn, end_pfn); 485 if (ret) 486 return ret; 487 nr_pages = end_pfn - start_pfn; 488 pfn = start_pfn; 489 expire = jiffies + timeout; 490 drain = 0; 491 retry_max = 5; 492 repeat: 493 /* start memory hot removal */ 494 ret = -EAGAIN; 495 if (time_after(jiffies, expire)) 496 goto failed_removal; 497 ret = -EINTR; 498 if (signal_pending(current)) 499 goto failed_removal; 500 ret = 0; 501 if (drain) { 502 lru_add_drain_all(); 503 flush_scheduled_work(); 504 cond_resched(); 505 drain_all_local_pages(); 506 } 507 508 pfn = scan_lru_pages(start_pfn, end_pfn); 509 if (pfn) { /* We have page on LRU */ 510 ret = do_migrate_range(pfn, end_pfn); 511 if (!ret) { 512 drain = 1; 513 goto repeat; 514 } else { 515 if (ret < 0) 516 if (--retry_max == 0) 517 goto failed_removal; 518 yield(); 519 drain = 1; 520 goto repeat; 521 } 522 } 523 /* drain all zone's lru pagevec, this is asyncronous... */ 524 lru_add_drain_all(); 525 flush_scheduled_work(); 526 yield(); 527 /* drain pcp pages , this is synchrouns. */ 528 drain_all_local_pages(); 529 /* check again */ 530 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 531 if (offlined_pages < 0) { 532 ret = -EBUSY; 533 goto failed_removal; 534 } 535 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 536 /* Ok, all of our target is islaoted. 537 We cannot do rollback at this point. */ 538 offline_isolated_pages(start_pfn, end_pfn); 539 /* reset pagetype flags */ 540 start_isolate_page_range(start_pfn, end_pfn); 541 /* removal success */ 542 zone = page_zone(pfn_to_page(start_pfn)); 543 zone->present_pages -= offlined_pages; 544 zone->zone_pgdat->node_present_pages -= offlined_pages; 545 totalram_pages -= offlined_pages; 546 num_physpages -= offlined_pages; 547 vm_total_pages = nr_free_pagecache_pages(); 548 writeback_set_ratelimit(); 549 return 0; 550 551 failed_removal: 552 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 553 start_pfn, end_pfn); 554 /* pushback to free area */ 555 undo_isolate_page_range(start_pfn, end_pfn); 556 return ret; 557 } 558 #else 559 int remove_memory(u64 start, u64 size) 560 { 561 return -EINVAL; 562 } 563 EXPORT_SYMBOL_GPL(remove_memory); 564 #endif /* CONFIG_MEMORY_HOTREMOVE */ 565