memory_hotplug.c 18.6 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
/*
 *  linux/mm/memory_hotplug.c
 *
 *  Copyright (C)
 */

#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/pagevec.h>
16
#include <linux/writeback.h>
17 18 19 20 21 22 23
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/highmem.h>
#include <linux/vmalloc.h>
24
#include <linux/ioport.h>
25
#include <linux/cpuset.h>
K
KAMEZAWA Hiroyuki 已提交
26 27 28
#include <linux/delay.h>
#include <linux/migrate.h>
#include <linux/page-isolation.h>
29 30 31

#include <asm/tlbflush.h>

32 33
#include "internal.h"

34 35 36 37 38 39 40 41 42 43
/* add this memory to iomem resource */
static struct resource *register_memory_resource(u64 start, u64 size)
{
	struct resource *res;
	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
	BUG_ON(!res);

	res->name = "System RAM";
	res->start = start;
	res->end = start + size - 1;
44
	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62
	if (request_resource(&iomem_resource, res) < 0) {
		printk("System RAM resource %llx - %llx cannot be added\n",
		(unsigned long long)res->start, (unsigned long long)res->end);
		kfree(res);
		res = NULL;
	}
	return res;
}

static void release_memory_resource(struct resource *res)
{
	if (!res)
		return;
	release_resource(res);
	kfree(res);
	return;
}

63
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161
#ifndef CONFIG_SPARSEMEM_VMEMMAP
static void get_page_bootmem(unsigned long info,  struct page *page, int magic)
{
	atomic_set(&page->_mapcount, magic);
	SetPagePrivate(page);
	set_page_private(page, info);
	atomic_inc(&page->_count);
}

void put_page_bootmem(struct page *page)
{
	int magic;

	magic = atomic_read(&page->_mapcount);
	BUG_ON(magic >= -1);

	if (atomic_dec_return(&page->_count) == 1) {
		ClearPagePrivate(page);
		set_page_private(page, 0);
		reset_page_mapcount(page);
		__free_pages_bootmem(page, 0);
	}

}

void register_page_bootmem_info_section(unsigned long start_pfn)
{
	unsigned long *usemap, mapsize, section_nr, i;
	struct mem_section *ms;
	struct page *page, *memmap;

	if (!pfn_valid(start_pfn))
		return;

	section_nr = pfn_to_section_nr(start_pfn);
	ms = __nr_to_section(section_nr);

	/* Get section's memmap address */
	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);

	/*
	 * Get page for the memmap's phys address
	 * XXX: need more consideration for sparse_vmemmap...
	 */
	page = virt_to_page(memmap);
	mapsize = sizeof(struct page) * PAGES_PER_SECTION;
	mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;

	/* remember memmap's page */
	for (i = 0; i < mapsize; i++, page++)
		get_page_bootmem(section_nr, page, SECTION_INFO);

	usemap = __nr_to_section(section_nr)->pageblock_flags;
	page = virt_to_page(usemap);

	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;

	for (i = 0; i < mapsize; i++, page++)
		get_page_bootmem(section_nr, page, MIX_INFO);

}

void register_page_bootmem_info_node(struct pglist_data *pgdat)
{
	unsigned long i, pfn, end_pfn, nr_pages;
	int node = pgdat->node_id;
	struct page *page;
	struct zone *zone;

	nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
	page = virt_to_page(pgdat);

	for (i = 0; i < nr_pages; i++, page++)
		get_page_bootmem(node, page, NODE_INFO);

	zone = &pgdat->node_zones[0];
	for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
		if (zone->wait_table) {
			nr_pages = zone->wait_table_hash_nr_entries
				* sizeof(wait_queue_head_t);
			nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
			page = virt_to_page(zone->wait_table);

			for (i = 0; i < nr_pages; i++, page++)
				get_page_bootmem(node, page, NODE_INFO);
		}
	}

	pfn = pgdat->node_start_pfn;
	end_pfn = pfn + pgdat->node_spanned_pages;

	/* register_section info */
	for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
		register_page_bootmem_info_section(pfn);

}
#endif /* !CONFIG_SPARSEMEM_VMEMMAP */

162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191
static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
			   unsigned long end_pfn)
{
	unsigned long old_zone_end_pfn;

	zone_span_writelock(zone);

	old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
	if (start_pfn < zone->zone_start_pfn)
		zone->zone_start_pfn = start_pfn;

	zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
				zone->zone_start_pfn;

	zone_span_writeunlock(zone);
}

static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
			    unsigned long end_pfn)
{
	unsigned long old_pgdat_end_pfn =
		pgdat->node_start_pfn + pgdat->node_spanned_pages;

	if (start_pfn < pgdat->node_start_pfn)
		pgdat->node_start_pfn = start_pfn;

	pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
					pgdat->node_start_pfn;
}

192
static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
193 194 195 196 197
{
	struct pglist_data *pgdat = zone->zone_pgdat;
	int nr_pages = PAGES_PER_SECTION;
	int nid = pgdat->node_id;
	int zone_type;
198
	unsigned long flags;
199 200

	zone_type = zone - pgdat->node_zones;
201 202 203 204 205 206 207 208 209 210 211 212 213
	if (!zone->wait_table) {
		int ret;

		ret = init_currently_empty_zone(zone, phys_start_pfn,
						nr_pages, MEMMAP_HOTPLUG);
		if (ret)
			return ret;
	}
	pgdat_resize_lock(zone->zone_pgdat, &flags);
	grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
	grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
			phys_start_pfn + nr_pages);
	pgdat_resize_unlock(zone->zone_pgdat, &flags);
D
Dave Hansen 已提交
214 215
	memmap_init_zone(nr_pages, nid, zone_type,
			 phys_start_pfn, MEMMAP_HOTPLUG);
216
	return 0;
217 218 219 220 221 222 223
}

static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
{
	int nr_pages = PAGES_PER_SECTION;
	int ret;

224 225 226
	if (pfn_valid(phys_start_pfn))
		return -EEXIST;

227
	ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
228 229 230 231

	if (ret < 0)
		return ret;

232 233 234 235 236
	ret = __add_zone(zone, phys_start_pfn);

	if (ret < 0)
		return ret;

237 238 239
	return register_new_memory(__pfn_to_section(phys_start_pfn));
}

240 241 242 243 244 245 246 247 248 249
#ifdef CONFIG_SPARSEMEM_VMEMMAP
static int __remove_section(struct zone *zone, struct mem_section *ms)
{
	/*
	 * XXX: Freeing memmap with vmemmap is not implement yet.
	 *      This should be removed later.
	 */
	return -EBUSY;
}
#else
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
static int __remove_section(struct zone *zone, struct mem_section *ms)
{
	unsigned long flags;
	struct pglist_data *pgdat = zone->zone_pgdat;
	int ret = -EINVAL;

	if (!valid_section(ms))
		return ret;

	ret = unregister_memory_section(ms);
	if (ret)
		return ret;

	pgdat_resize_lock(pgdat, &flags);
	sparse_remove_one_section(zone, ms);
	pgdat_resize_unlock(pgdat, &flags);
	return 0;
}
268
#endif
269

270 271 272 273 274 275 276 277 278 279 280
/*
 * Reasonably generic function for adding memory.  It is
 * expected that archs that support memory hotplug will
 * call this function after deciding the zone to which to
 * add the new pages.
 */
int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
		 unsigned long nr_pages)
{
	unsigned long i;
	int err = 0;
281 282 283 284
	int start_sec, end_sec;
	/* during initialize mem_map, align hot-added range to section */
	start_sec = pfn_to_section_nr(phys_start_pfn);
	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
285

286 287
	for (i = start_sec; i <= end_sec; i++) {
		err = __add_section(zone, i << PFN_SECTION_SHIFT);
288

289
		/*
S
Simon Arlott 已提交
290
		 * EEXIST is finally dealt with by ioresource collision
291 292
		 * check. see add_memory() => register_memory_resource()
		 * Warning will be printed if there is collision.
293 294
		 */
		if (err && (err != -EEXIST))
295
			break;
296
		err = 0;
297 298 299 300
	}

	return err;
}
301
EXPORT_SYMBOL_GPL(__add_pages);
302

303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338
/**
 * __remove_pages() - remove sections of pages from a zone
 * @zone: zone from which pages need to be removed
 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
 * @nr_pages: number of pages to remove (must be multiple of section size)
 *
 * Generic helper function to remove section mappings and sysfs entries
 * for the section of the memory we are removing. Caller needs to make
 * sure that pages are marked reserved and zones are adjust properly by
 * calling offline_pages().
 */
int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
		 unsigned long nr_pages)
{
	unsigned long i, ret = 0;
	int sections_to_remove;

	/*
	 * We can only remove entire sections
	 */
	BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
	BUG_ON(nr_pages % PAGES_PER_SECTION);

	release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);

	sections_to_remove = nr_pages / PAGES_PER_SECTION;
	for (i = 0; i < sections_to_remove; i++) {
		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
		ret = __remove_section(zone, __pfn_to_section(pfn));
		if (ret)
			break;
	}
	return ret;
}
EXPORT_SYMBOL_GPL(__remove_pages);

339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357
void online_page(struct page *page)
{
	totalram_pages++;
	num_physpages++;

#ifdef CONFIG_HIGHMEM
	if (PageHighMem(page))
		totalhigh_pages++;
#endif

#ifdef CONFIG_FLATMEM
	max_mapnr = max(page_to_pfn(page), max_mapnr);
#endif

	ClearPageReserved(page);
	init_page_count(page);
	__free_page(page);
}

358 359
static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
			void *arg)
360 361
{
	unsigned long i;
362 363 364 365 366 367 368 369 370 371 372 373 374 375 376
	unsigned long onlined_pages = *(unsigned long *)arg;
	struct page *page;
	if (PageReserved(pfn_to_page(start_pfn)))
		for (i = 0; i < nr_pages; i++) {
			page = pfn_to_page(start_pfn + i);
			online_page(page);
			onlined_pages++;
		}
	*(unsigned long *)arg = onlined_pages;
	return 0;
}


int online_pages(unsigned long pfn, unsigned long nr_pages)
{
377 378
	unsigned long onlined_pages = 0;
	struct zone *zone;
379
	int need_zonelists_rebuild = 0;
380 381 382 383 384 385 386 387 388 389 390
	int nid;
	int ret;
	struct memory_notify arg;

	arg.start_pfn = pfn;
	arg.nr_pages = nr_pages;
	arg.status_change_nid = -1;

	nid = page_to_nid(pfn_to_page(pfn));
	if (node_present_pages(nid) == 0)
		arg.status_change_nid = nid;
391

392 393 394 395 396 397
	ret = memory_notify(MEM_GOING_ONLINE, &arg);
	ret = notifier_to_errno(ret);
	if (ret) {
		memory_notify(MEM_CANCEL_ONLINE, &arg);
		return ret;
	}
398 399 400
	/*
	 * This doesn't need a lock to do pfn_to_page().
	 * The section can't be removed here because of the
401
	 * memory_block->state_mutex.
402 403
	 */
	zone = page_zone(pfn_to_page(pfn));
404 405 406 407 408 409 410 411
	/*
	 * If this zone is not populated, then it is not in zonelist.
	 * This means the page allocator ignores this zone.
	 * So, zonelist must be updated after online.
	 */
	if (!populated_zone(zone))
		need_zonelists_rebuild = 1;

412
	ret = walk_memory_resource(pfn, nr_pages, &onlined_pages,
413
		online_pages_range);
414 415 416 417 418 419 420
	if (ret) {
		printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
			nr_pages, pfn);
		memory_notify(MEM_CANCEL_ONLINE, &arg);
		return ret;
	}

421
	zone->present_pages += onlined_pages;
422
	zone->zone_pgdat->node_present_pages += onlined_pages;
423

424
	setup_per_zone_pages_min();
425 426 427 428
	if (onlined_pages) {
		kswapd_run(zone_to_nid(zone));
		node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
	}
429

430 431
	if (need_zonelists_rebuild)
		build_all_zonelists();
432
	vm_total_pages = nr_free_pagecache_pages();
433
	writeback_set_ratelimit();
434 435 436 437

	if (onlined_pages)
		memory_notify(MEM_ONLINE, &arg);

438 439
	return 0;
}
440
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
441

442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457
static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
{
	struct pglist_data *pgdat;
	unsigned long zones_size[MAX_NR_ZONES] = {0};
	unsigned long zholes_size[MAX_NR_ZONES] = {0};
	unsigned long start_pfn = start >> PAGE_SHIFT;

	pgdat = arch_alloc_nodedata(nid);
	if (!pgdat)
		return NULL;

	arch_refresh_nodedata(nid, pgdat);

	/* we can use NODE_DATA(nid) from here */

	/* init node's zones as empty zones, we don't have any present pages.*/
458
	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
459 460 461 462 463 464 465 466 467 468 469

	return pgdat;
}

static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
{
	arch_refresh_nodedata(nid, NULL);
	arch_free_nodedata(pgdat);
	return;
}

470

471 472
int add_memory(int nid, u64 start, u64 size)
{
473 474
	pg_data_t *pgdat = NULL;
	int new_pgdat = 0;
475
	struct resource *res;
476 477
	int ret;

478 479 480 481
	res = register_memory_resource(start, size);
	if (!res)
		return -EEXIST;

482 483 484 485 486 487 488
	if (!node_online(nid)) {
		pgdat = hotadd_new_pgdat(nid, start);
		if (!pgdat)
			return -ENOMEM;
		new_pgdat = 1;
	}

489 490 491
	/* call arch's memory hotadd */
	ret = arch_add_memory(nid, start, size);

492 493 494
	if (ret < 0)
		goto error;

495
	/* we online node here. we can't roll back from here. */
496 497
	node_set_online(nid);

498 499
	cpuset_track_online_nodes();

500 501 502 503 504 505 506 507 508 509
	if (new_pgdat) {
		ret = register_one_node(nid);
		/*
		 * If sysfs file of new node can't create, cpu on the node
		 * can't be hot-added. There is no rollback way now.
		 * So, check by BUG_ON() to catch it reluctantly..
		 */
		BUG_ON(ret);
	}

510 511 512 513 514
	return ret;
error:
	/* rollback pgdat allocation and others */
	if (new_pgdat)
		rollback_node_hotadd(nid, pgdat);
515 516
	if (res)
		release_memory_resource(res);
517

518 519 520
	return ret;
}
EXPORT_SYMBOL_GPL(add_memory);
K
KAMEZAWA Hiroyuki 已提交
521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680

#ifdef CONFIG_MEMORY_HOTREMOVE
/*
 * Confirm all pages in a range [start, end) is belongs to the same zone.
 */
static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
{
	unsigned long pfn;
	struct zone *zone = NULL;
	struct page *page;
	int i;
	for (pfn = start_pfn;
	     pfn < end_pfn;
	     pfn += MAX_ORDER_NR_PAGES) {
		i = 0;
		/* This is just a CONFIG_HOLES_IN_ZONE check.*/
		while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
			i++;
		if (i == MAX_ORDER_NR_PAGES)
			continue;
		page = pfn_to_page(pfn + i);
		if (zone && page_zone(page) != zone)
			return 0;
		zone = page_zone(page);
	}
	return 1;
}

/*
 * Scanning pfn is much easier than scanning lru list.
 * Scan pfn from start to end and Find LRU page.
 */
int scan_lru_pages(unsigned long start, unsigned long end)
{
	unsigned long pfn;
	struct page *page;
	for (pfn = start; pfn < end; pfn++) {
		if (pfn_valid(pfn)) {
			page = pfn_to_page(pfn);
			if (PageLRU(page))
				return pfn;
		}
	}
	return 0;
}

static struct page *
hotremove_migrate_alloc(struct page *page,
			unsigned long private,
			int **x)
{
	/* This should be improoooooved!! */
	return alloc_page(GFP_HIGHUSER_PAGECACHE);
}


#define NR_OFFLINE_AT_ONCE_PAGES	(256)
static int
do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
{
	unsigned long pfn;
	struct page *page;
	int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
	int not_managed = 0;
	int ret = 0;
	LIST_HEAD(source);

	for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
		if (!pfn_valid(pfn))
			continue;
		page = pfn_to_page(pfn);
		if (!page_count(page))
			continue;
		/*
		 * We can skip free pages. And we can only deal with pages on
		 * LRU.
		 */
		ret = isolate_lru_page(page, &source);
		if (!ret) { /* Success */
			move_pages--;
		} else {
			/* Becasue we don't have big zone->lock. we should
			   check this again here. */
			if (page_count(page))
				not_managed++;
#ifdef CONFIG_DEBUG_VM
			printk(KERN_INFO "removing from LRU failed"
					 " %lx/%d/%lx\n",
				pfn, page_count(page), page->flags);
#endif
		}
	}
	ret = -EBUSY;
	if (not_managed) {
		if (!list_empty(&source))
			putback_lru_pages(&source);
		goto out;
	}
	ret = 0;
	if (list_empty(&source))
		goto out;
	/* this function returns # of failed pages */
	ret = migrate_pages(&source, hotremove_migrate_alloc, 0);

out:
	return ret;
}

/*
 * remove from free_area[] and mark all as Reserved.
 */
static int
offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
			void *data)
{
	__offline_isolated_pages(start, start + nr_pages);
	return 0;
}

static void
offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
{
	walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
				offline_isolated_pages_cb);
}

/*
 * Check all pages in range, recoreded as memory resource, are isolated.
 */
static int
check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
			void *data)
{
	int ret;
	long offlined = *(long *)data;
	ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
	offlined = nr_pages;
	if (!ret)
		*(long *)data += offlined;
	return ret;
}

static long
check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
{
	long offlined = 0;
	int ret;

	ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
			check_pages_isolated_cb);
	if (ret < 0)
		offlined = (long)ret;
	return offlined;
}

int offline_pages(unsigned long start_pfn,
		  unsigned long end_pfn, unsigned long timeout)
{
	unsigned long pfn, nr_pages, expire;
	long offlined_pages;
681
	int ret, drain, retry_max, node;
K
KAMEZAWA Hiroyuki 已提交
682
	struct zone *zone;
683
	struct memory_notify arg;
K
KAMEZAWA Hiroyuki 已提交
684 685 686 687 688 689 690 691 692 693 694

	BUG_ON(start_pfn >= end_pfn);
	/* at least, alignment against pageblock is necessary */
	if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
		return -EINVAL;
	if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
		return -EINVAL;
	/* This makes hotplug much easier...and readable.
	   we assume this for now. .*/
	if (!test_pages_in_a_zone(start_pfn, end_pfn))
		return -EINVAL;
695 696 697 698 699

	zone = page_zone(pfn_to_page(start_pfn));
	node = zone_to_nid(zone);
	nr_pages = end_pfn - start_pfn;

K
KAMEZAWA Hiroyuki 已提交
700 701 702 703
	/* set above range as isolated */
	ret = start_isolate_page_range(start_pfn, end_pfn);
	if (ret)
		return ret;
704 705 706 707 708 709 710 711 712 713 714 715

	arg.start_pfn = start_pfn;
	arg.nr_pages = nr_pages;
	arg.status_change_nid = -1;
	if (nr_pages >= node_present_pages(node))
		arg.status_change_nid = node;

	ret = memory_notify(MEM_GOING_OFFLINE, &arg);
	ret = notifier_to_errno(ret);
	if (ret)
		goto failed_removal;

K
KAMEZAWA Hiroyuki 已提交
716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732
	pfn = start_pfn;
	expire = jiffies + timeout;
	drain = 0;
	retry_max = 5;
repeat:
	/* start memory hot removal */
	ret = -EAGAIN;
	if (time_after(jiffies, expire))
		goto failed_removal;
	ret = -EINTR;
	if (signal_pending(current))
		goto failed_removal;
	ret = 0;
	if (drain) {
		lru_add_drain_all();
		flush_scheduled_work();
		cond_resched();
733
		drain_all_pages();
K
KAMEZAWA Hiroyuki 已提交
734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755
	}

	pfn = scan_lru_pages(start_pfn, end_pfn);
	if (pfn) { /* We have page on LRU */
		ret = do_migrate_range(pfn, end_pfn);
		if (!ret) {
			drain = 1;
			goto repeat;
		} else {
			if (ret < 0)
				if (--retry_max == 0)
					goto failed_removal;
			yield();
			drain = 1;
			goto repeat;
		}
	}
	/* drain all zone's lru pagevec, this is asyncronous... */
	lru_add_drain_all();
	flush_scheduled_work();
	yield();
	/* drain pcp pages , this is synchrouns. */
756
	drain_all_pages();
K
KAMEZAWA Hiroyuki 已提交
757 758 759 760 761 762 763 764 765 766
	/* check again */
	offlined_pages = check_pages_isolated(start_pfn, end_pfn);
	if (offlined_pages < 0) {
		ret = -EBUSY;
		goto failed_removal;
	}
	printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
	/* Ok, all of our target is islaoted.
	   We cannot do rollback at this point. */
	offline_isolated_pages(start_pfn, end_pfn);
767 768
	/* reset pagetype flags and makes migrate type to be MOVABLE */
	undo_isolate_page_range(start_pfn, end_pfn);
K
KAMEZAWA Hiroyuki 已提交
769 770 771 772 773
	/* removal success */
	zone->present_pages -= offlined_pages;
	zone->zone_pgdat->node_present_pages -= offlined_pages;
	totalram_pages -= offlined_pages;
	num_physpages -= offlined_pages;
774

K
KAMEZAWA Hiroyuki 已提交
775 776
	vm_total_pages = nr_free_pagecache_pages();
	writeback_set_ratelimit();
777 778

	memory_notify(MEM_OFFLINE, &arg);
K
KAMEZAWA Hiroyuki 已提交
779 780 781 782 783
	return 0;

failed_removal:
	printk(KERN_INFO "memory offlining %lx to %lx failed\n",
		start_pfn, end_pfn);
784
	memory_notify(MEM_CANCEL_OFFLINE, &arg);
K
KAMEZAWA Hiroyuki 已提交
785 786
	/* pushback to free area */
	undo_isolate_page_range(start_pfn, end_pfn);
787

K
KAMEZAWA Hiroyuki 已提交
788 789
	return ret;
}
790 791 792 793 794 795
#else
int remove_memory(u64 start, u64 size)
{
	return -EINVAL;
}
EXPORT_SYMBOL_GPL(remove_memory);
K
KAMEZAWA Hiroyuki 已提交
796
#endif /* CONFIG_MEMORY_HOTREMOVE */