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/compiler.h>
  13#include <linux/export.h>
  14#include <linux/pagevec.h>
  15#include <linux/writeback.h>
  16#include <linux/slab.h>
  17#include <linux/sysctl.h>
  18#include <linux/cpu.h>
  19#include <linux/memory.h>
  20#include <linux/memremap.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#include <linux/hugetlb.h>
  34#include <linux/memblock.h>
  35#include <linux/bootmem.h>
  36#include <linux/compaction.h>
  37
  38#include <asm/tlbflush.h>
  39
  40#include "internal.h"
  41
  42/*
  43 * online_page_callback contains pointer to current page onlining function.
  44 * Initially it is generic_online_page(). If it is required it could be
  45 * changed by calling set_online_page_callback() for callback registration
  46 * and restore_online_page_callback() for generic callback restore.
  47 */
  48
  49static void generic_online_page(struct page *page);
  50
  51static online_page_callback_t online_page_callback = generic_online_page;
  52static DEFINE_MUTEX(online_page_callback_lock);
  53
  54/* The same as the cpu_hotplug lock, but for memory hotplug. */
  55static struct {
  56	struct task_struct *active_writer;
  57	struct mutex lock; /* Synchronizes accesses to refcount, */
  58	/*
  59	 * Also blocks the new readers during
  60	 * an ongoing mem hotplug operation.
  61	 */
  62	int refcount;
  63
  64#ifdef CONFIG_DEBUG_LOCK_ALLOC
  65	struct lockdep_map dep_map;
  66#endif
  67} mem_hotplug = {
  68	.active_writer = NULL,
  69	.lock = __MUTEX_INITIALIZER(mem_hotplug.lock),
  70	.refcount = 0,
  71#ifdef CONFIG_DEBUG_LOCK_ALLOC
  72	.dep_map = {.name = "mem_hotplug.lock" },
  73#endif
  74};
  75
  76/* Lockdep annotations for get/put_online_mems() and mem_hotplug_begin/end() */
  77#define memhp_lock_acquire_read() lock_map_acquire_read(&mem_hotplug.dep_map)
  78#define memhp_lock_acquire()      lock_map_acquire(&mem_hotplug.dep_map)
  79#define memhp_lock_release()      lock_map_release(&mem_hotplug.dep_map)
  80
 
  81bool memhp_auto_online;
 
 
 
  82EXPORT_SYMBOL_GPL(memhp_auto_online);
  83
 
 
 
 
 
 
 
 
 
 
 
  84void get_online_mems(void)
  85{
  86	might_sleep();
  87	if (mem_hotplug.active_writer == current)
  88		return;
  89	memhp_lock_acquire_read();
  90	mutex_lock(&mem_hotplug.lock);
  91	mem_hotplug.refcount++;
  92	mutex_unlock(&mem_hotplug.lock);
  93
  94}
  95
  96void put_online_mems(void)
  97{
  98	if (mem_hotplug.active_writer == current)
  99		return;
 100	mutex_lock(&mem_hotplug.lock);
 101
 102	if (WARN_ON(!mem_hotplug.refcount))
 103		mem_hotplug.refcount++; /* try to fix things up */
 104
 105	if (!--mem_hotplug.refcount && unlikely(mem_hotplug.active_writer))
 106		wake_up_process(mem_hotplug.active_writer);
 107	mutex_unlock(&mem_hotplug.lock);
 108	memhp_lock_release();
 109
 110}
 111
 112void mem_hotplug_begin(void)
 113{
 114	mem_hotplug.active_writer = current;
 115
 116	memhp_lock_acquire();
 117	for (;;) {
 118		mutex_lock(&mem_hotplug.lock);
 119		if (likely(!mem_hotplug.refcount))
 120			break;
 121		__set_current_state(TASK_UNINTERRUPTIBLE);
 122		mutex_unlock(&mem_hotplug.lock);
 123		schedule();
 124	}
 125}
 126
 127void mem_hotplug_done(void)
 128{
 129	mem_hotplug.active_writer = NULL;
 130	mutex_unlock(&mem_hotplug.lock);
 131	memhp_lock_release();
 132}
 133
 134/* add this memory to iomem resource */
 135static struct resource *register_memory_resource(u64 start, u64 size)
 136{
 137	struct resource *res;
 138	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 139	if (!res)
 140		return ERR_PTR(-ENOMEM);
 141
 142	res->name = "System RAM";
 143	res->start = start;
 144	res->end = start + size - 1;
 145	res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 146	if (request_resource(&iomem_resource, res) < 0) {
 147		pr_debug("System RAM resource %pR cannot be added\n", res);
 148		kfree(res);
 149		return ERR_PTR(-EEXIST);
 150	}
 151	return res;
 152}
 153
 154static void release_memory_resource(struct resource *res)
 155{
 156	if (!res)
 157		return;
 158	release_resource(res);
 159	kfree(res);
 160	return;
 161}
 162
 163#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 164void get_page_bootmem(unsigned long info,  struct page *page,
 165		      unsigned long type)
 166{
 167	page->lru.next = (struct list_head *) type;
 168	SetPagePrivate(page);
 169	set_page_private(page, info);
 170	page_ref_inc(page);
 171}
 172
 173void put_page_bootmem(struct page *page)
 174{
 175	unsigned long type;
 176
 177	type = (unsigned long) page->lru.next;
 178	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
 179	       type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
 180
 181	if (page_ref_dec_return(page) == 1) {
 182		ClearPagePrivate(page);
 183		set_page_private(page, 0);
 184		INIT_LIST_HEAD(&page->lru);
 185		free_reserved_page(page);
 186	}
 187}
 188
 189#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
 190#ifndef CONFIG_SPARSEMEM_VMEMMAP
 191static void register_page_bootmem_info_section(unsigned long start_pfn)
 192{
 193	unsigned long *usemap, mapsize, section_nr, i;
 194	struct mem_section *ms;
 195	struct page *page, *memmap;
 196
 197	section_nr = pfn_to_section_nr(start_pfn);
 198	ms = __nr_to_section(section_nr);
 199
 200	/* Get section's memmap address */
 201	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 202
 203	/*
 204	 * Get page for the memmap's phys address
 205	 * XXX: need more consideration for sparse_vmemmap...
 206	 */
 207	page = virt_to_page(memmap);
 208	mapsize = sizeof(struct page) * PAGES_PER_SECTION;
 209	mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
 210
 211	/* remember memmap's page */
 212	for (i = 0; i < mapsize; i++, page++)
 213		get_page_bootmem(section_nr, page, SECTION_INFO);
 214
 215	usemap = __nr_to_section(section_nr)->pageblock_flags;
 216	page = virt_to_page(usemap);
 217
 218	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 219
 220	for (i = 0; i < mapsize; i++, page++)
 221		get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 222
 223}
 224#else /* CONFIG_SPARSEMEM_VMEMMAP */
 225static void register_page_bootmem_info_section(unsigned long start_pfn)
 226{
 227	unsigned long *usemap, mapsize, section_nr, i;
 228	struct mem_section *ms;
 229	struct page *page, *memmap;
 230
 231	if (!pfn_valid(start_pfn))
 232		return;
 233
 234	section_nr = pfn_to_section_nr(start_pfn);
 235	ms = __nr_to_section(section_nr);
 236
 237	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
 238
 239	register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
 240
 241	usemap = __nr_to_section(section_nr)->pageblock_flags;
 242	page = virt_to_page(usemap);
 243
 244	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 245
 246	for (i = 0; i < mapsize; i++, page++)
 247		get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 248}
 249#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 250
 251void register_page_bootmem_info_node(struct pglist_data *pgdat)
 252{
 253	unsigned long i, pfn, end_pfn, nr_pages;
 254	int node = pgdat->node_id;
 255	struct page *page;
 256	struct zone *zone;
 257
 258	nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
 259	page = virt_to_page(pgdat);
 260
 261	for (i = 0; i < nr_pages; i++, page++)
 262		get_page_bootmem(node, page, NODE_INFO);
 263
 264	zone = &pgdat->node_zones[0];
 265	for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
 266		if (zone_is_initialized(zone)) {
 267			nr_pages = zone->wait_table_hash_nr_entries
 268				* sizeof(wait_queue_head_t);
 269			nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
 270			page = virt_to_page(zone->wait_table);
 271
 272			for (i = 0; i < nr_pages; i++, page++)
 273				get_page_bootmem(node, page, NODE_INFO);
 274		}
 275	}
 276
 277	pfn = pgdat->node_start_pfn;
 278	end_pfn = pgdat_end_pfn(pgdat);
 279
 280	/* register section info */
 281	for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 282		/*
 283		 * Some platforms can assign the same pfn to multiple nodes - on
 284		 * node0 as well as nodeN.  To avoid registering a pfn against
 285		 * multiple nodes we check that this pfn does not already
 286		 * reside in some other nodes.
 287		 */
 288		if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
 289			register_page_bootmem_info_section(pfn);
 290	}
 291}
 292#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
 293
 294static void __meminit grow_zone_span(struct zone *zone, unsigned long start_pfn,
 295				     unsigned long end_pfn)
 296{
 297	unsigned long old_zone_end_pfn;
 298
 299	zone_span_writelock(zone);
 300
 301	old_zone_end_pfn = zone_end_pfn(zone);
 302	if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
 303		zone->zone_start_pfn = start_pfn;
 304
 305	zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
 306				zone->zone_start_pfn;
 307
 308	zone_span_writeunlock(zone);
 309}
 310
 311static void resize_zone(struct zone *zone, unsigned long start_pfn,
 312		unsigned long end_pfn)
 313{
 314	zone_span_writelock(zone);
 315
 316	if (end_pfn - start_pfn) {
 317		zone->zone_start_pfn = start_pfn;
 318		zone->spanned_pages = end_pfn - start_pfn;
 319	} else {
 320		/*
 321		 * make it consist as free_area_init_core(),
 322		 * if spanned_pages = 0, then keep start_pfn = 0
 323		 */
 324		zone->zone_start_pfn = 0;
 325		zone->spanned_pages = 0;
 326	}
 327
 328	zone_span_writeunlock(zone);
 329}
 330
 331static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
 332		unsigned long end_pfn)
 333{
 334	enum zone_type zid = zone_idx(zone);
 335	int nid = zone->zone_pgdat->node_id;
 336	unsigned long pfn;
 337
 338	for (pfn = start_pfn; pfn < end_pfn; pfn++)
 339		set_page_links(pfn_to_page(pfn), zid, nid, pfn);
 340}
 341
 342/* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
 343 * alloc_bootmem_node_nopanic()/memblock_virt_alloc_node_nopanic() */
 344static int __ref ensure_zone_is_initialized(struct zone *zone,
 345			unsigned long start_pfn, unsigned long num_pages)
 346{
 347	if (!zone_is_initialized(zone))
 348		return init_currently_empty_zone(zone, start_pfn, num_pages);
 349
 350	return 0;
 351}
 352
 353static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
 354		unsigned long start_pfn, unsigned long end_pfn)
 355{
 356	int ret;
 357	unsigned long flags;
 358	unsigned long z1_start_pfn;
 359
 360	ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
 361	if (ret)
 362		return ret;
 363
 364	pgdat_resize_lock(z1->zone_pgdat, &flags);
 365
 366	/* can't move pfns which are higher than @z2 */
 367	if (end_pfn > zone_end_pfn(z2))
 368		goto out_fail;
 369	/* the move out part must be at the left most of @z2 */
 370	if (start_pfn > z2->zone_start_pfn)
 371		goto out_fail;
 372	/* must included/overlap */
 373	if (end_pfn <= z2->zone_start_pfn)
 374		goto out_fail;
 375
 376	/* use start_pfn for z1's start_pfn if z1 is empty */
 377	if (!zone_is_empty(z1))
 378		z1_start_pfn = z1->zone_start_pfn;
 379	else
 380		z1_start_pfn = start_pfn;
 381
 382	resize_zone(z1, z1_start_pfn, end_pfn);
 383	resize_zone(z2, end_pfn, zone_end_pfn(z2));
 384
 385	pgdat_resize_unlock(z1->zone_pgdat, &flags);
 386
 387	fix_zone_id(z1, start_pfn, end_pfn);
 388
 389	return 0;
 390out_fail:
 391	pgdat_resize_unlock(z1->zone_pgdat, &flags);
 392	return -1;
 393}
 394
 395static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
 396		unsigned long start_pfn, unsigned long end_pfn)
 397{
 398	int ret;
 399	unsigned long flags;
 400	unsigned long z2_end_pfn;
 401
 402	ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
 403	if (ret)
 404		return ret;
 405
 406	pgdat_resize_lock(z1->zone_pgdat, &flags);
 407
 408	/* can't move pfns which are lower than @z1 */
 409	if (z1->zone_start_pfn > start_pfn)
 410		goto out_fail;
 411	/* the move out part mast at the right most of @z1 */
 412	if (zone_end_pfn(z1) >  end_pfn)
 413		goto out_fail;
 414	/* must included/overlap */
 415	if (start_pfn >= zone_end_pfn(z1))
 416		goto out_fail;
 417
 418	/* use end_pfn for z2's end_pfn if z2 is empty */
 419	if (!zone_is_empty(z2))
 420		z2_end_pfn = zone_end_pfn(z2);
 421	else
 422		z2_end_pfn = end_pfn;
 423
 424	resize_zone(z1, z1->zone_start_pfn, start_pfn);
 425	resize_zone(z2, start_pfn, z2_end_pfn);
 426
 427	pgdat_resize_unlock(z1->zone_pgdat, &flags);
 428
 429	fix_zone_id(z2, start_pfn, end_pfn);
 430
 431	return 0;
 432out_fail:
 433	pgdat_resize_unlock(z1->zone_pgdat, &flags);
 434	return -1;
 435}
 436
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 437static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
 438				      unsigned long end_pfn)
 439{
 440	unsigned long old_pgdat_end_pfn = pgdat_end_pfn(pgdat);
 441
 442	if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
 443		pgdat->node_start_pfn = start_pfn;
 444
 445	pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
 446					pgdat->node_start_pfn;
 447}
 448
 449static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 450{
 451	struct pglist_data *pgdat = zone->zone_pgdat;
 452	int nr_pages = PAGES_PER_SECTION;
 453	int nid = pgdat->node_id;
 454	int zone_type;
 455	unsigned long flags, pfn;
 456	int ret;
 457
 458	zone_type = zone - pgdat->node_zones;
 459	ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
 460	if (ret)
 461		return ret;
 462
 463	pgdat_resize_lock(zone->zone_pgdat, &flags);
 464	grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
 465	grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
 466			phys_start_pfn + nr_pages);
 467	pgdat_resize_unlock(zone->zone_pgdat, &flags);
 468	memmap_init_zone(nr_pages, nid, zone_type,
 469			 phys_start_pfn, MEMMAP_HOTPLUG);
 470
 471	/* online_page_range is called later and expects pages reserved */
 472	for (pfn = phys_start_pfn; pfn < phys_start_pfn + nr_pages; pfn++) {
 473		if (!pfn_valid(pfn))
 474			continue;
 475
 476		SetPageReserved(pfn_to_page(pfn));
 477	}
 478	return 0;
 479}
 480
 481static int __meminit __add_section(int nid, struct zone *zone,
 482					unsigned long phys_start_pfn)
 483{
 484	int ret;
 485
 486	if (pfn_valid(phys_start_pfn))
 487		return -EEXIST;
 488
 489	ret = sparse_add_one_section(zone, phys_start_pfn);
 490
 491	if (ret < 0)
 492		return ret;
 493
 494	ret = __add_zone(zone, phys_start_pfn);
 495
 496	if (ret < 0)
 497		return ret;
 498
 499	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
 500}
 501
 502/*
 503 * Reasonably generic function for adding memory.  It is
 504 * expected that archs that support memory hotplug will
 505 * call this function after deciding the zone to which to
 506 * add the new pages.
 507 */
 508int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 509			unsigned long nr_pages)
 510{
 511	unsigned long i;
 512	int err = 0;
 513	int start_sec, end_sec;
 514	struct vmem_altmap *altmap;
 515
 516	clear_zone_contiguous(zone);
 517
 518	/* during initialize mem_map, align hot-added range to section */
 519	start_sec = pfn_to_section_nr(phys_start_pfn);
 520	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 521
 522	altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
 523	if (altmap) {
 524		/*
 525		 * Validate altmap is within bounds of the total request
 526		 */
 527		if (altmap->base_pfn != phys_start_pfn
 528				|| vmem_altmap_offset(altmap) > nr_pages) {
 529			pr_warn_once("memory add fail, invalid altmap\n");
 530			err = -EINVAL;
 531			goto out;
 532		}
 533		altmap->alloc = 0;
 534	}
 535
 536	for (i = start_sec; i <= end_sec; i++) {
 537		err = __add_section(nid, zone, section_nr_to_pfn(i));
 538
 539		/*
 540		 * EEXIST is finally dealt with by ioresource collision
 541		 * check. see add_memory() => register_memory_resource()
 542		 * Warning will be printed if there is collision.
 543		 */
 544		if (err && (err != -EEXIST))
 545			break;
 546		err = 0;
 547	}
 548	vmemmap_populate_print_last();
 549out:
 550	set_zone_contiguous(zone);
 551	return err;
 552}
 553EXPORT_SYMBOL_GPL(__add_pages);
 554
 555#ifdef CONFIG_MEMORY_HOTREMOVE
 556/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
 557static int find_smallest_section_pfn(int nid, struct zone *zone,
 558				     unsigned long start_pfn,
 559				     unsigned long end_pfn)
 560{
 561	struct mem_section *ms;
 562
 563	for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
 564		ms = __pfn_to_section(start_pfn);
 565
 566		if (unlikely(!valid_section(ms)))
 567			continue;
 568
 569		if (unlikely(pfn_to_nid(start_pfn) != nid))
 570			continue;
 571
 572		if (zone && zone != page_zone(pfn_to_page(start_pfn)))
 573			continue;
 574
 575		return start_pfn;
 576	}
 577
 578	return 0;
 579}
 580
 581/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
 582static int find_biggest_section_pfn(int nid, struct zone *zone,
 583				    unsigned long start_pfn,
 584				    unsigned long end_pfn)
 585{
 586	struct mem_section *ms;
 587	unsigned long pfn;
 588
 589	/* pfn is the end pfn of a memory section. */
 590	pfn = end_pfn - 1;
 591	for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
 592		ms = __pfn_to_section(pfn);
 593
 594		if (unlikely(!valid_section(ms)))
 595			continue;
 596
 597		if (unlikely(pfn_to_nid(pfn) != nid))
 598			continue;
 599
 600		if (zone && zone != page_zone(pfn_to_page(pfn)))
 601			continue;
 602
 603		return pfn;
 604	}
 605
 606	return 0;
 607}
 608
 609static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
 610			     unsigned long end_pfn)
 611{
 612	unsigned long zone_start_pfn = zone->zone_start_pfn;
 613	unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
 614	unsigned long zone_end_pfn = z;
 615	unsigned long pfn;
 616	struct mem_section *ms;
 617	int nid = zone_to_nid(zone);
 618
 619	zone_span_writelock(zone);
 620	if (zone_start_pfn == start_pfn) {
 621		/*
 622		 * If the section is smallest section in the zone, it need
 623		 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
 624		 * In this case, we find second smallest valid mem_section
 625		 * for shrinking zone.
 626		 */
 627		pfn = find_smallest_section_pfn(nid, zone, end_pfn,
 628						zone_end_pfn);
 629		if (pfn) {
 630			zone->zone_start_pfn = pfn;
 631			zone->spanned_pages = zone_end_pfn - pfn;
 632		}
 633	} else if (zone_end_pfn == end_pfn) {
 634		/*
 635		 * If the section is biggest section in the zone, it need
 636		 * shrink zone->spanned_pages.
 637		 * In this case, we find second biggest valid mem_section for
 638		 * shrinking zone.
 639		 */
 640		pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
 641					       start_pfn);
 642		if (pfn)
 643			zone->spanned_pages = pfn - zone_start_pfn + 1;
 644	}
 645
 646	/*
 647	 * The section is not biggest or smallest mem_section in the zone, it
 648	 * only creates a hole in the zone. So in this case, we need not
 649	 * change the zone. But perhaps, the zone has only hole data. Thus
 650	 * it check the zone has only hole or not.
 651	 */
 652	pfn = zone_start_pfn;
 653	for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
 654		ms = __pfn_to_section(pfn);
 655
 656		if (unlikely(!valid_section(ms)))
 657			continue;
 658
 659		if (page_zone(pfn_to_page(pfn)) != zone)
 660			continue;
 661
 662		 /* If the section is current section, it continues the loop */
 663		if (start_pfn == pfn)
 664			continue;
 665
 666		/* If we find valid section, we have nothing to do */
 667		zone_span_writeunlock(zone);
 668		return;
 669	}
 670
 671	/* The zone has no valid section */
 672	zone->zone_start_pfn = 0;
 673	zone->spanned_pages = 0;
 674	zone_span_writeunlock(zone);
 675}
 676
 677static void shrink_pgdat_span(struct pglist_data *pgdat,
 678			      unsigned long start_pfn, unsigned long end_pfn)
 679{
 680	unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
 681	unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
 682	unsigned long pgdat_end_pfn = p;
 683	unsigned long pfn;
 684	struct mem_section *ms;
 685	int nid = pgdat->node_id;
 686
 687	if (pgdat_start_pfn == start_pfn) {
 688		/*
 689		 * If the section is smallest section in the pgdat, it need
 690		 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
 691		 * In this case, we find second smallest valid mem_section
 692		 * for shrinking zone.
 693		 */
 694		pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
 695						pgdat_end_pfn);
 696		if (pfn) {
 697			pgdat->node_start_pfn = pfn;
 698			pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
 699		}
 700	} else if (pgdat_end_pfn == end_pfn) {
 701		/*
 702		 * If the section is biggest section in the pgdat, it need
 703		 * shrink pgdat->node_spanned_pages.
 704		 * In this case, we find second biggest valid mem_section for
 705		 * shrinking zone.
 706		 */
 707		pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
 708					       start_pfn);
 709		if (pfn)
 710			pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
 711	}
 712
 713	/*
 714	 * If the section is not biggest or smallest mem_section in the pgdat,
 715	 * it only creates a hole in the pgdat. So in this case, we need not
 716	 * change the pgdat.
 717	 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
 718	 * has only hole or not.
 719	 */
 720	pfn = pgdat_start_pfn;
 721	for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
 722		ms = __pfn_to_section(pfn);
 723
 724		if (unlikely(!valid_section(ms)))
 725			continue;
 726
 727		if (pfn_to_nid(pfn) != nid)
 728			continue;
 729
 730		 /* If the section is current section, it continues the loop */
 731		if (start_pfn == pfn)
 732			continue;
 733
 734		/* If we find valid section, we have nothing to do */
 735		return;
 736	}
 737
 738	/* The pgdat has no valid section */
 739	pgdat->node_start_pfn = 0;
 740	pgdat->node_spanned_pages = 0;
 741}
 742
 743static void __remove_zone(struct zone *zone, unsigned long start_pfn)
 744{
 745	struct pglist_data *pgdat = zone->zone_pgdat;
 746	int nr_pages = PAGES_PER_SECTION;
 747	int zone_type;
 748	unsigned long flags;
 749
 750	zone_type = zone - pgdat->node_zones;
 751
 752	pgdat_resize_lock(zone->zone_pgdat, &flags);
 753	shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
 754	shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
 755	pgdat_resize_unlock(zone->zone_pgdat, &flags);
 756}
 757
 758static int __remove_section(struct zone *zone, struct mem_section *ms,
 759		unsigned long map_offset)
 760{
 761	unsigned long start_pfn;
 762	int scn_nr;
 763	int ret = -EINVAL;
 764
 765	if (!valid_section(ms))
 766		return ret;
 767
 768	ret = unregister_memory_section(ms);
 769	if (ret)
 770		return ret;
 771
 772	scn_nr = __section_nr(ms);
 773	start_pfn = section_nr_to_pfn(scn_nr);
 774	__remove_zone(zone, start_pfn);
 775
 776	sparse_remove_one_section(zone, ms, map_offset);
 777	return 0;
 778}
 779
 780/**
 781 * __remove_pages() - remove sections of pages from a zone
 782 * @zone: zone from which pages need to be removed
 783 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
 784 * @nr_pages: number of pages to remove (must be multiple of section size)
 785 *
 786 * Generic helper function to remove section mappings and sysfs entries
 787 * for the section of the memory we are removing. Caller needs to make
 788 * sure that pages are marked reserved and zones are adjust properly by
 789 * calling offline_pages().
 790 */
 791int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 792		 unsigned long nr_pages)
 793{
 794	unsigned long i;
 795	unsigned long map_offset = 0;
 796	int sections_to_remove, ret = 0;
 797
 798	/* In the ZONE_DEVICE case device driver owns the memory region */
 799	if (is_dev_zone(zone)) {
 800		struct page *page = pfn_to_page(phys_start_pfn);
 801		struct vmem_altmap *altmap;
 802
 803		altmap = to_vmem_altmap((unsigned long) page);
 804		if (altmap)
 805			map_offset = vmem_altmap_offset(altmap);
 806	} else {
 807		resource_size_t start, size;
 808
 809		start = phys_start_pfn << PAGE_SHIFT;
 810		size = nr_pages * PAGE_SIZE;
 811
 812		ret = release_mem_region_adjustable(&iomem_resource, start,
 813					size);
 814		if (ret) {
 815			resource_size_t endres = start + size - 1;
 816
 817			pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
 818					&start, &endres, ret);
 819		}
 820	}
 821
 822	clear_zone_contiguous(zone);
 823
 824	/*
 825	 * We can only remove entire sections
 826	 */
 827	BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 828	BUG_ON(nr_pages % PAGES_PER_SECTION);
 829
 830	sections_to_remove = nr_pages / PAGES_PER_SECTION;
 831	for (i = 0; i < sections_to_remove; i++) {
 832		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
 833
 834		ret = __remove_section(zone, __pfn_to_section(pfn), map_offset);
 835		map_offset = 0;
 836		if (ret)
 837			break;
 838	}
 839
 840	set_zone_contiguous(zone);
 841
 842	return ret;
 843}
 844EXPORT_SYMBOL_GPL(__remove_pages);
 845#endif /* CONFIG_MEMORY_HOTREMOVE */
 846
 847int set_online_page_callback(online_page_callback_t callback)
 848{
 849	int rc = -EINVAL;
 850
 851	get_online_mems();
 852	mutex_lock(&online_page_callback_lock);
 853
 854	if (online_page_callback == generic_online_page) {
 855		online_page_callback = callback;
 856		rc = 0;
 857	}
 858
 859	mutex_unlock(&online_page_callback_lock);
 860	put_online_mems();
 861
 862	return rc;
 863}
 864EXPORT_SYMBOL_GPL(set_online_page_callback);
 865
 866int restore_online_page_callback(online_page_callback_t callback)
 867{
 868	int rc = -EINVAL;
 869
 870	get_online_mems();
 871	mutex_lock(&online_page_callback_lock);
 872
 873	if (online_page_callback == callback) {
 874		online_page_callback = generic_online_page;
 875		rc = 0;
 876	}
 877
 878	mutex_unlock(&online_page_callback_lock);
 879	put_online_mems();
 880
 881	return rc;
 882}
 883EXPORT_SYMBOL_GPL(restore_online_page_callback);
 884
 885void __online_page_set_limits(struct page *page)
 886{
 887}
 888EXPORT_SYMBOL_GPL(__online_page_set_limits);
 889
 890void __online_page_increment_counters(struct page *page)
 891{
 892	adjust_managed_page_count(page, 1);
 893}
 894EXPORT_SYMBOL_GPL(__online_page_increment_counters);
 895
 896void __online_page_free(struct page *page)
 897{
 898	__free_reserved_page(page);
 899}
 900EXPORT_SYMBOL_GPL(__online_page_free);
 901
 902static void generic_online_page(struct page *page)
 903{
 904	__online_page_set_limits(page);
 905	__online_page_increment_counters(page);
 906	__online_page_free(page);
 907}
 908
 909static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 910			void *arg)
 911{
 912	unsigned long i;
 913	unsigned long onlined_pages = *(unsigned long *)arg;
 914	struct page *page;
 915	if (PageReserved(pfn_to_page(start_pfn)))
 916		for (i = 0; i < nr_pages; i++) {
 917			page = pfn_to_page(start_pfn + i);
 918			(*online_page_callback)(page);
 919			onlined_pages++;
 920		}
 921	*(unsigned long *)arg = onlined_pages;
 922	return 0;
 923}
 924
 925#ifdef CONFIG_MOVABLE_NODE
 926/*
 927 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
 928 * normal memory.
 929 */
 930static bool can_online_high_movable(struct zone *zone)
 931{
 932	return true;
 933}
 934#else /* CONFIG_MOVABLE_NODE */
 935/* ensure every online node has NORMAL memory */
 936static bool can_online_high_movable(struct zone *zone)
 937{
 938	return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
 939}
 940#endif /* CONFIG_MOVABLE_NODE */
 941
 942/* check which state of node_states will be changed when online memory */
 943static void node_states_check_changes_online(unsigned long nr_pages,
 944	struct zone *zone, struct memory_notify *arg)
 945{
 946	int nid = zone_to_nid(zone);
 947	enum zone_type zone_last = ZONE_NORMAL;
 948
 949	/*
 950	 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
 951	 * contains nodes which have zones of 0...ZONE_NORMAL,
 952	 * set zone_last to ZONE_NORMAL.
 953	 *
 954	 * If we don't have HIGHMEM nor movable node,
 955	 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
 956	 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
 957	 */
 958	if (N_MEMORY == N_NORMAL_MEMORY)
 959		zone_last = ZONE_MOVABLE;
 960
 961	/*
 962	 * if the memory to be online is in a zone of 0...zone_last, and
 963	 * the zones of 0...zone_last don't have memory before online, we will
 964	 * need to set the node to node_states[N_NORMAL_MEMORY] after
 965	 * the memory is online.
 966	 */
 967	if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
 968		arg->status_change_nid_normal = nid;
 969	else
 970		arg->status_change_nid_normal = -1;
 971
 972#ifdef CONFIG_HIGHMEM
 973	/*
 974	 * If we have movable node, node_states[N_HIGH_MEMORY]
 975	 * contains nodes which have zones of 0...ZONE_HIGHMEM,
 976	 * set zone_last to ZONE_HIGHMEM.
 977	 *
 978	 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
 979	 * contains nodes which have zones of 0...ZONE_MOVABLE,
 980	 * set zone_last to ZONE_MOVABLE.
 981	 */
 982	zone_last = ZONE_HIGHMEM;
 983	if (N_MEMORY == N_HIGH_MEMORY)
 984		zone_last = ZONE_MOVABLE;
 985
 986	if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
 987		arg->status_change_nid_high = nid;
 988	else
 989		arg->status_change_nid_high = -1;
 990#else
 991	arg->status_change_nid_high = arg->status_change_nid_normal;
 992#endif
 993
 994	/*
 995	 * if the node don't have memory befor online, we will need to
 996	 * set the node to node_states[N_MEMORY] after the memory
 997	 * is online.
 998	 */
 999	if (!node_state(nid, N_MEMORY))
1000		arg->status_change_nid = nid;
1001	else
1002		arg->status_change_nid = -1;
1003}
1004
1005static void node_states_set_node(int node, struct memory_notify *arg)
1006{
1007	if (arg->status_change_nid_normal >= 0)
1008		node_set_state(node, N_NORMAL_MEMORY);
1009
1010	if (arg->status_change_nid_high >= 0)
1011		node_set_state(node, N_HIGH_MEMORY);
1012
1013	node_set_state(node, N_MEMORY);
1014}
1015
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1016
1017/* Must be protected by mem_hotplug_begin() */
1018int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
1019{
1020	unsigned long flags;
1021	unsigned long onlined_pages = 0;
1022	struct zone *zone;
1023	int need_zonelists_rebuild = 0;
1024	int nid;
1025	int ret;
1026	struct memory_notify arg;
 
1027
1028	/*
1029	 * This doesn't need a lock to do pfn_to_page().
1030	 * The section can't be removed here because of the
1031	 * memory_block->state_mutex.
1032	 */
1033	zone = page_zone(pfn_to_page(pfn));
1034
1035	if ((zone_idx(zone) > ZONE_NORMAL ||
1036	    online_type == MMOP_ONLINE_MOVABLE) &&
1037	    !can_online_high_movable(zone))
1038		return -EINVAL;
1039
1040	if (online_type == MMOP_ONLINE_KERNEL &&
1041	    zone_idx(zone) == ZONE_MOVABLE) {
1042		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
1043			return -EINVAL;
1044	}
1045	if (online_type == MMOP_ONLINE_MOVABLE &&
1046	    zone_idx(zone) == ZONE_MOVABLE - 1) {
1047		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
1048			return -EINVAL;
1049	}
1050
1051	/* Previous code may changed the zone of the pfn range */
1052	zone = page_zone(pfn_to_page(pfn));
 
1053
1054	arg.start_pfn = pfn;
1055	arg.nr_pages = nr_pages;
1056	node_states_check_changes_online(nr_pages, zone, &arg);
1057
1058	nid = zone_to_nid(zone);
1059
1060	ret = memory_notify(MEM_GOING_ONLINE, &arg);
1061	ret = notifier_to_errno(ret);
1062	if (ret)
1063		goto failed_addition;
1064
1065	/*
1066	 * If this zone is not populated, then it is not in zonelist.
1067	 * This means the page allocator ignores this zone.
1068	 * So, zonelist must be updated after online.
1069	 */
1070	mutex_lock(&zonelists_mutex);
1071	if (!populated_zone(zone)) {
1072		need_zonelists_rebuild = 1;
1073		build_all_zonelists(NULL, zone);
1074	}
1075
1076	ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
1077		online_pages_range);
1078	if (ret) {
1079		if (need_zonelists_rebuild)
1080			zone_pcp_reset(zone);
1081		mutex_unlock(&zonelists_mutex);
1082		goto failed_addition;
1083	}
1084
1085	zone->present_pages += onlined_pages;
1086
1087	pgdat_resize_lock(zone->zone_pgdat, &flags);
1088	zone->zone_pgdat->node_present_pages += onlined_pages;
1089	pgdat_resize_unlock(zone->zone_pgdat, &flags);
1090
1091	if (onlined_pages) {
1092		node_states_set_node(nid, &arg);
1093		if (need_zonelists_rebuild)
1094			build_all_zonelists(NULL, NULL);
1095		else
1096			zone_pcp_update(zone);
1097	}
1098
1099	mutex_unlock(&zonelists_mutex);
1100
1101	init_per_zone_wmark_min();
1102
1103	if (onlined_pages) {
1104		kswapd_run(nid);
1105		kcompactd_run(nid);
1106	}
1107
1108	vm_total_pages = nr_free_pagecache_pages();
1109
1110	writeback_set_ratelimit();
1111
1112	if (onlined_pages)
1113		memory_notify(MEM_ONLINE, &arg);
1114	return 0;
1115
1116failed_addition:
1117	pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1118		 (unsigned long long) pfn << PAGE_SHIFT,
1119		 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1120	memory_notify(MEM_CANCEL_ONLINE, &arg);
1121	return ret;
1122}
1123#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1124
1125static void reset_node_present_pages(pg_data_t *pgdat)
1126{
1127	struct zone *z;
1128
1129	for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
1130		z->present_pages = 0;
1131
1132	pgdat->node_present_pages = 0;
1133}
1134
1135/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1136static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1137{
1138	struct pglist_data *pgdat;
1139	unsigned long zones_size[MAX_NR_ZONES] = {0};
1140	unsigned long zholes_size[MAX_NR_ZONES] = {0};
1141	unsigned long start_pfn = PFN_DOWN(start);
1142
1143	pgdat = NODE_DATA(nid);
1144	if (!pgdat) {
1145		pgdat = arch_alloc_nodedata(nid);
1146		if (!pgdat)
1147			return NULL;
1148
1149		arch_refresh_nodedata(nid, pgdat);
1150	} else {
1151		/* Reset the nr_zones and classzone_idx to 0 before reuse */
1152		pgdat->nr_zones = 0;
1153		pgdat->classzone_idx = 0;
 
1154	}
1155
1156	/* we can use NODE_DATA(nid) from here */
1157
1158	/* init node's zones as empty zones, we don't have any present pages.*/
1159	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
 
1160
1161	/*
1162	 * The node we allocated has no zone fallback lists. For avoiding
1163	 * to access not-initialized zonelist, build here.
1164	 */
1165	mutex_lock(&zonelists_mutex);
1166	build_all_zonelists(pgdat, NULL);
1167	mutex_unlock(&zonelists_mutex);
1168
1169	/*
1170	 * zone->managed_pages is set to an approximate value in
1171	 * free_area_init_core(), which will cause
1172	 * /sys/device/system/node/nodeX/meminfo has wrong data.
1173	 * So reset it to 0 before any memory is onlined.
1174	 */
1175	reset_node_managed_pages(pgdat);
1176
1177	/*
1178	 * When memory is hot-added, all the memory is in offline state. So
1179	 * clear all zones' present_pages because they will be updated in
1180	 * online_pages() and offline_pages().
1181	 */
1182	reset_node_present_pages(pgdat);
1183
1184	return pgdat;
1185}
1186
1187static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1188{
1189	arch_refresh_nodedata(nid, NULL);
 
1190	arch_free_nodedata(pgdat);
1191	return;
1192}
1193
1194
1195/**
1196 * try_online_node - online a node if offlined
1197 *
1198 * called by cpu_up() to online a node without onlined memory.
1199 */
1200int try_online_node(int nid)
1201{
1202	pg_data_t	*pgdat;
1203	int	ret;
1204
1205	if (node_online(nid))
1206		return 0;
1207
1208	mem_hotplug_begin();
1209	pgdat = hotadd_new_pgdat(nid, 0);
1210	if (!pgdat) {
1211		pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1212		ret = -ENOMEM;
1213		goto out;
1214	}
1215	node_set_online(nid);
1216	ret = register_one_node(nid);
1217	BUG_ON(ret);
1218
1219	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
1220		mutex_lock(&zonelists_mutex);
1221		build_all_zonelists(NULL, NULL);
1222		mutex_unlock(&zonelists_mutex);
1223	}
1224
1225out:
1226	mem_hotplug_done();
1227	return ret;
1228}
1229
1230static int check_hotplug_memory_range(u64 start, u64 size)
1231{
1232	u64 start_pfn = PFN_DOWN(start);
1233	u64 nr_pages = size >> PAGE_SHIFT;
1234
1235	/* Memory range must be aligned with section */
1236	if ((start_pfn & ~PAGE_SECTION_MASK) ||
1237	    (nr_pages % PAGES_PER_SECTION) || (!nr_pages)) {
1238		pr_err("Section-unaligned hotplug range: start 0x%llx, size 0x%llx\n",
1239				(unsigned long long)start,
1240				(unsigned long long)size);
1241		return -EINVAL;
1242	}
1243
1244	return 0;
1245}
1246
1247/*
1248 * If movable zone has already been setup, newly added memory should be check.
1249 * If its address is higher than movable zone, it should be added as movable.
1250 * Without this check, movable zone may overlap with other zone.
1251 */
1252static int should_add_memory_movable(int nid, u64 start, u64 size)
1253{
1254	unsigned long start_pfn = start >> PAGE_SHIFT;
1255	pg_data_t *pgdat = NODE_DATA(nid);
1256	struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
1257
1258	if (zone_is_empty(movable_zone))
1259		return 0;
1260
1261	if (movable_zone->zone_start_pfn <= start_pfn)
1262		return 1;
1263
1264	return 0;
1265}
1266
1267int zone_for_memory(int nid, u64 start, u64 size, int zone_default,
1268		bool for_device)
1269{
1270#ifdef CONFIG_ZONE_DEVICE
1271	if (for_device)
1272		return ZONE_DEVICE;
1273#endif
1274	if (should_add_memory_movable(nid, start, size))
1275		return ZONE_MOVABLE;
1276
1277	return zone_default;
1278}
1279
1280static int online_memory_block(struct memory_block *mem, void *arg)
1281{
1282	return memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
1283}
1284
1285/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1286int __ref add_memory_resource(int nid, struct resource *res, bool online)
1287{
1288	u64 start, size;
1289	pg_data_t *pgdat = NULL;
1290	bool new_pgdat;
1291	bool new_node;
1292	int ret;
1293
1294	start = res->start;
1295	size = resource_size(res);
1296
1297	ret = check_hotplug_memory_range(start, size);
1298	if (ret)
1299		return ret;
1300
1301	{	/* Stupid hack to suppress address-never-null warning */
1302		void *p = NODE_DATA(nid);
1303		new_pgdat = !p;
1304	}
1305
1306	mem_hotplug_begin();
1307
1308	/*
1309	 * Add new range to memblock so that when hotadd_new_pgdat() is called
1310	 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1311	 * this new range and calculate total pages correctly.  The range will
1312	 * be removed at hot-remove time.
1313	 */
1314	memblock_add_node(start, size, nid);
1315
1316	new_node = !node_online(nid);
1317	if (new_node) {
1318		pgdat = hotadd_new_pgdat(nid, start);
1319		ret = -ENOMEM;
1320		if (!pgdat)
1321			goto error;
1322	}
1323
1324	/* call arch's memory hotadd */
1325	ret = arch_add_memory(nid, start, size, false);
1326
1327	if (ret < 0)
1328		goto error;
1329
1330	/* we online node here. we can't roll back from here. */
1331	node_set_online(nid);
1332
1333	if (new_node) {
1334		ret = register_one_node(nid);
1335		/*
1336		 * If sysfs file of new node can't create, cpu on the node
1337		 * can't be hot-added. There is no rollback way now.
1338		 * So, check by BUG_ON() to catch it reluctantly..
1339		 */
1340		BUG_ON(ret);
1341	}
1342
1343	/* create new memmap entry */
1344	firmware_map_add_hotplug(start, start + size, "System RAM");
1345
1346	/* online pages if requested */
1347	if (online)
1348		walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
1349				  NULL, online_memory_block);
1350
1351	goto out;
1352
1353error:
1354	/* rollback pgdat allocation and others */
1355	if (new_pgdat)
1356		rollback_node_hotadd(nid, pgdat);
1357	memblock_remove(start, size);
1358
1359out:
1360	mem_hotplug_done();
1361	return ret;
1362}
1363EXPORT_SYMBOL_GPL(add_memory_resource);
1364
1365int __ref add_memory(int nid, u64 start, u64 size)
1366{
1367	struct resource *res;
1368	int ret;
1369
1370	res = register_memory_resource(start, size);
1371	if (IS_ERR(res))
1372		return PTR_ERR(res);
1373
1374	ret = add_memory_resource(nid, res, memhp_auto_online);
1375	if (ret < 0)
1376		release_memory_resource(res);
1377	return ret;
1378}
1379EXPORT_SYMBOL_GPL(add_memory);
1380
1381#ifdef CONFIG_MEMORY_HOTREMOVE
1382/*
1383 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1384 * set and the size of the free page is given by page_order(). Using this,
1385 * the function determines if the pageblock contains only free pages.
1386 * Due to buddy contraints, a free page at least the size of a pageblock will
1387 * be located at the start of the pageblock
1388 */
1389static inline int pageblock_free(struct page *page)
1390{
1391	return PageBuddy(page) && page_order(page) >= pageblock_order;
1392}
1393
1394/* Return the start of the next active pageblock after a given page */
1395static struct page *next_active_pageblock(struct page *page)
1396{
1397	/* Ensure the starting page is pageblock-aligned */
1398	BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1399
1400	/* If the entire pageblock is free, move to the end of free page */
1401	if (pageblock_free(page)) {
1402		int order;
1403		/* be careful. we don't have locks, page_order can be changed.*/
1404		order = page_order(page);
1405		if ((order < MAX_ORDER) && (order >= pageblock_order))
1406			return page + (1 << order);
1407	}
1408
1409	return page + pageblock_nr_pages;
1410}
1411
1412/* Checks if this range of memory is likely to be hot-removable. */
1413int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1414{
1415	struct page *page = pfn_to_page(start_pfn);
1416	struct page *end_page = page + nr_pages;
1417
1418	/* Check the starting page of each pageblock within the range */
1419	for (; page < end_page; page = next_active_pageblock(page)) {
1420		if (!is_pageblock_removable_nolock(page))
1421			return 0;
1422		cond_resched();
1423	}
1424
1425	/* All pageblocks in the memory block are likely to be hot-removable */
1426	return 1;
1427}
1428
1429/*
1430 * Confirm all pages in a range [start, end) is belongs to the same zone.
 
1431 */
1432int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
 
1433{
1434	unsigned long pfn, sec_end_pfn;
 
1435	struct zone *zone = NULL;
1436	struct page *page;
1437	int i;
1438	for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn);
1439	     pfn < end_pfn;
1440	     pfn = sec_end_pfn + 1, sec_end_pfn += PAGES_PER_SECTION) {
1441		/* Make sure the memory section is present first */
1442		if (!present_section_nr(pfn_to_section_nr(pfn)))
1443			continue;
1444		for (; pfn < sec_end_pfn && pfn < end_pfn;
1445		     pfn += MAX_ORDER_NR_PAGES) {
1446			i = 0;
1447			/* This is just a CONFIG_HOLES_IN_ZONE check.*/
1448			while ((i < MAX_ORDER_NR_PAGES) &&
1449				!pfn_valid_within(pfn + i))
1450				i++;
1451			if (i == MAX_ORDER_NR_PAGES)
1452				continue;
1453			page = pfn_to_page(pfn + i);
1454			if (zone && page_zone(page) != zone)
1455				return 0;
 
 
1456			zone = page_zone(page);
 
1457		}
1458	}
1459	return 1;
 
 
 
 
 
 
 
1460}
1461
1462/*
1463 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages
1464 * and hugepages). We scan pfn because it's much easier than scanning over
1465 * linked list. This function returns the pfn of the first found movable
1466 * page if it's found, otherwise 0.
1467 */
1468static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1469{
1470	unsigned long pfn;
1471	struct page *page;
1472	for (pfn = start; pfn < end; pfn++) {
1473		if (pfn_valid(pfn)) {
1474			page = pfn_to_page(pfn);
1475			if (PageLRU(page))
1476				return pfn;
1477			if (PageHuge(page)) {
1478				if (page_huge_active(page))
1479					return pfn;
1480				else
1481					pfn = round_up(pfn + 1,
1482						1 << compound_order(page)) - 1;
1483			}
1484		}
1485	}
1486	return 0;
1487}
1488
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1489#define NR_OFFLINE_AT_ONCE_PAGES	(256)
1490static int
1491do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1492{
1493	unsigned long pfn;
1494	struct page *page;
1495	int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1496	int not_managed = 0;
1497	int ret = 0;
1498	LIST_HEAD(source);
1499
1500	for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1501		if (!pfn_valid(pfn))
1502			continue;
1503		page = pfn_to_page(pfn);
1504
1505		if (PageHuge(page)) {
1506			struct page *head = compound_head(page);
1507			pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1508			if (compound_order(head) > PFN_SECTION_SHIFT) {
1509				ret = -EBUSY;
1510				break;
1511			}
1512			if (isolate_huge_page(page, &source))
1513				move_pages -= 1 << compound_order(head);
1514			continue;
1515		}
1516
1517		if (!get_page_unless_zero(page))
1518			continue;
1519		/*
1520		 * We can skip free pages. And we can only deal with pages on
1521		 * LRU.
1522		 */
1523		ret = isolate_lru_page(page);
1524		if (!ret) { /* Success */
1525			put_page(page);
1526			list_add_tail(&page->lru, &source);
1527			move_pages--;
1528			inc_zone_page_state(page, NR_ISOLATED_ANON +
1529					    page_is_file_cache(page));
1530
1531		} else {
1532#ifdef CONFIG_DEBUG_VM
1533			pr_alert("removing pfn %lx from LRU failed\n", pfn);
1534			dump_page(page, "failed to remove from LRU");
1535#endif
1536			put_page(page);
1537			/* Because we don't have big zone->lock. we should
1538			   check this again here. */
1539			if (page_count(page)) {
1540				not_managed++;
1541				ret = -EBUSY;
1542				break;
1543			}
1544		}
1545	}
1546	if (!list_empty(&source)) {
1547		if (not_managed) {
1548			putback_movable_pages(&source);
1549			goto out;
1550		}
1551
1552		/*
1553		 * alloc_migrate_target should be improooooved!!
1554		 * migrate_pages returns # of failed pages.
1555		 */
1556		ret = migrate_pages(&source, alloc_migrate_target, NULL, 0,
1557					MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1558		if (ret)
1559			putback_movable_pages(&source);
1560	}
1561out:
1562	return ret;
1563}
1564
1565/*
1566 * remove from free_area[] and mark all as Reserved.
1567 */
1568static int
1569offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1570			void *data)
1571{
1572	__offline_isolated_pages(start, start + nr_pages);
1573	return 0;
1574}
1575
1576static void
1577offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1578{
1579	walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1580				offline_isolated_pages_cb);
1581}
1582
1583/*
1584 * Check all pages in range, recoreded as memory resource, are isolated.
1585 */
1586static int
1587check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1588			void *data)
1589{
1590	int ret;
1591	long offlined = *(long *)data;
1592	ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1593	offlined = nr_pages;
1594	if (!ret)
1595		*(long *)data += offlined;
1596	return ret;
1597}
1598
1599static long
1600check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1601{
1602	long offlined = 0;
1603	int ret;
1604
1605	ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1606			check_pages_isolated_cb);
1607	if (ret < 0)
1608		offlined = (long)ret;
1609	return offlined;
1610}
1611
1612#ifdef CONFIG_MOVABLE_NODE
1613/*
1614 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1615 * normal memory.
1616 */
1617static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1618{
1619	return true;
1620}
1621#else /* CONFIG_MOVABLE_NODE */
1622/* ensure the node has NORMAL memory if it is still online */
1623static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1624{
1625	struct pglist_data *pgdat = zone->zone_pgdat;
1626	unsigned long present_pages = 0;
1627	enum zone_type zt;
1628
1629	for (zt = 0; zt <= ZONE_NORMAL; zt++)
1630		present_pages += pgdat->node_zones[zt].present_pages;
1631
1632	if (present_pages > nr_pages)
1633		return true;
1634
1635	present_pages = 0;
1636	for (; zt <= ZONE_MOVABLE; zt++)
1637		present_pages += pgdat->node_zones[zt].present_pages;
1638
1639	/*
1640	 * we can't offline the last normal memory until all
1641	 * higher memory is offlined.
1642	 */
1643	return present_pages == 0;
1644}
1645#endif /* CONFIG_MOVABLE_NODE */
1646
1647static int __init cmdline_parse_movable_node(char *p)
1648{
1649#ifdef CONFIG_MOVABLE_NODE
1650	/*
1651	 * Memory used by the kernel cannot be hot-removed because Linux
1652	 * cannot migrate the kernel pages. When memory hotplug is
1653	 * enabled, we should prevent memblock from allocating memory
1654	 * for the kernel.
1655	 *
1656	 * ACPI SRAT records all hotpluggable memory ranges. But before
1657	 * SRAT is parsed, we don't know about it.
1658	 *
1659	 * The kernel image is loaded into memory at very early time. We
1660	 * cannot prevent this anyway. So on NUMA system, we set any
1661	 * node the kernel resides in as un-hotpluggable.
1662	 *
1663	 * Since on modern servers, one node could have double-digit
1664	 * gigabytes memory, we can assume the memory around the kernel
1665	 * image is also un-hotpluggable. So before SRAT is parsed, just
1666	 * allocate memory near the kernel image to try the best to keep
1667	 * the kernel away from hotpluggable memory.
1668	 */
1669	memblock_set_bottom_up(true);
1670	movable_node_enabled = true;
1671#else
1672	pr_warn("movable_node option not supported\n");
1673#endif
1674	return 0;
1675}
1676early_param("movable_node", cmdline_parse_movable_node);
1677
1678/* check which state of node_states will be changed when offline memory */
1679static void node_states_check_changes_offline(unsigned long nr_pages,
1680		struct zone *zone, struct memory_notify *arg)
1681{
1682	struct pglist_data *pgdat = zone->zone_pgdat;
1683	unsigned long present_pages = 0;
1684	enum zone_type zt, zone_last = ZONE_NORMAL;
1685
1686	/*
1687	 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1688	 * contains nodes which have zones of 0...ZONE_NORMAL,
1689	 * set zone_last to ZONE_NORMAL.
1690	 *
1691	 * If we don't have HIGHMEM nor movable node,
1692	 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1693	 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1694	 */
1695	if (N_MEMORY == N_NORMAL_MEMORY)
1696		zone_last = ZONE_MOVABLE;
1697
1698	/*
1699	 * check whether node_states[N_NORMAL_MEMORY] will be changed.
1700	 * If the memory to be offline is in a zone of 0...zone_last,
1701	 * and it is the last present memory, 0...zone_last will
1702	 * become empty after offline , thus we can determind we will
1703	 * need to clear the node from node_states[N_NORMAL_MEMORY].
1704	 */
1705	for (zt = 0; zt <= zone_last; zt++)
1706		present_pages += pgdat->node_zones[zt].present_pages;
1707	if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1708		arg->status_change_nid_normal = zone_to_nid(zone);
1709	else
1710		arg->status_change_nid_normal = -1;
1711
1712#ifdef CONFIG_HIGHMEM
1713	/*
1714	 * If we have movable node, node_states[N_HIGH_MEMORY]
1715	 * contains nodes which have zones of 0...ZONE_HIGHMEM,
1716	 * set zone_last to ZONE_HIGHMEM.
1717	 *
1718	 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1719	 * contains nodes which have zones of 0...ZONE_MOVABLE,
1720	 * set zone_last to ZONE_MOVABLE.
1721	 */
1722	zone_last = ZONE_HIGHMEM;
1723	if (N_MEMORY == N_HIGH_MEMORY)
1724		zone_last = ZONE_MOVABLE;
1725
1726	for (; zt <= zone_last; zt++)
1727		present_pages += pgdat->node_zones[zt].present_pages;
1728	if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1729		arg->status_change_nid_high = zone_to_nid(zone);
1730	else
1731		arg->status_change_nid_high = -1;
1732#else
1733	arg->status_change_nid_high = arg->status_change_nid_normal;
1734#endif
1735
1736	/*
1737	 * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1738	 */
1739	zone_last = ZONE_MOVABLE;
1740
1741	/*
1742	 * check whether node_states[N_HIGH_MEMORY] will be changed
1743	 * If we try to offline the last present @nr_pages from the node,
1744	 * we can determind we will need to clear the node from
1745	 * node_states[N_HIGH_MEMORY].
1746	 */
1747	for (; zt <= zone_last; zt++)
1748		present_pages += pgdat->node_zones[zt].present_pages;
1749	if (nr_pages >= present_pages)
1750		arg->status_change_nid = zone_to_nid(zone);
1751	else
1752		arg->status_change_nid = -1;
1753}
1754
1755static void node_states_clear_node(int node, struct memory_notify *arg)
1756{
1757	if (arg->status_change_nid_normal >= 0)
1758		node_clear_state(node, N_NORMAL_MEMORY);
1759
1760	if ((N_MEMORY != N_NORMAL_MEMORY) &&
1761	    (arg->status_change_nid_high >= 0))
1762		node_clear_state(node, N_HIGH_MEMORY);
1763
1764	if ((N_MEMORY != N_HIGH_MEMORY) &&
1765	    (arg->status_change_nid >= 0))
1766		node_clear_state(node, N_MEMORY);
1767}
1768
1769static int __ref __offline_pages(unsigned long start_pfn,
1770		  unsigned long end_pfn, unsigned long timeout)
1771{
1772	unsigned long pfn, nr_pages, expire;
1773	long offlined_pages;
1774	int ret, drain, retry_max, node;
1775	unsigned long flags;
 
1776	struct zone *zone;
1777	struct memory_notify arg;
1778
1779	/* at least, alignment against pageblock is necessary */
1780	if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1781		return -EINVAL;
1782	if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1783		return -EINVAL;
1784	/* This makes hotplug much easier...and readable.
1785	   we assume this for now. .*/
1786	if (!test_pages_in_a_zone(start_pfn, end_pfn))
1787		return -EINVAL;
1788
1789	zone = page_zone(pfn_to_page(start_pfn));
1790	node = zone_to_nid(zone);
1791	nr_pages = end_pfn - start_pfn;
1792
1793	if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1794		return -EINVAL;
1795
1796	/* set above range as isolated */
1797	ret = start_isolate_page_range(start_pfn, end_pfn,
1798				       MIGRATE_MOVABLE, true);
1799	if (ret)
1800		return ret;
1801
1802	arg.start_pfn = start_pfn;
1803	arg.nr_pages = nr_pages;
1804	node_states_check_changes_offline(nr_pages, zone, &arg);
1805
1806	ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1807	ret = notifier_to_errno(ret);
1808	if (ret)
1809		goto failed_removal;
1810
1811	pfn = start_pfn;
1812	expire = jiffies + timeout;
1813	drain = 0;
1814	retry_max = 5;
1815repeat:
1816	/* start memory hot removal */
1817	ret = -EAGAIN;
1818	if (time_after(jiffies, expire))
1819		goto failed_removal;
1820	ret = -EINTR;
1821	if (signal_pending(current))
1822		goto failed_removal;
1823	ret = 0;
1824	if (drain) {
1825		lru_add_drain_all();
1826		cond_resched();
1827		drain_all_pages(zone);
1828	}
1829
1830	pfn = scan_movable_pages(start_pfn, end_pfn);
1831	if (pfn) { /* We have movable pages */
1832		ret = do_migrate_range(pfn, end_pfn);
1833		if (!ret) {
1834			drain = 1;
1835			goto repeat;
1836		} else {
1837			if (ret < 0)
1838				if (--retry_max == 0)
1839					goto failed_removal;
1840			yield();
1841			drain = 1;
1842			goto repeat;
1843		}
1844	}
1845	/* drain all zone's lru pagevec, this is asynchronous... */
1846	lru_add_drain_all();
1847	yield();
1848	/* drain pcp pages, this is synchronous. */
1849	drain_all_pages(zone);
1850	/*
1851	 * dissolve free hugepages in the memory block before doing offlining
1852	 * actually in order to make hugetlbfs's object counting consistent.
1853	 */
1854	dissolve_free_huge_pages(start_pfn, end_pfn);
 
 
1855	/* check again */
1856	offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1857	if (offlined_pages < 0) {
1858		ret = -EBUSY;
1859		goto failed_removal;
1860	}
1861	pr_info("Offlined Pages %ld\n", offlined_pages);
1862	/* Ok, all of our target is isolated.
1863	   We cannot do rollback at this point. */
1864	offline_isolated_pages(start_pfn, end_pfn);
1865	/* reset pagetype flags and makes migrate type to be MOVABLE */
1866	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1867	/* removal success */
1868	adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1869	zone->present_pages -= offlined_pages;
1870
1871	pgdat_resize_lock(zone->zone_pgdat, &flags);
1872	zone->zone_pgdat->node_present_pages -= offlined_pages;
1873	pgdat_resize_unlock(zone->zone_pgdat, &flags);
1874
1875	init_per_zone_wmark_min();
1876
1877	if (!populated_zone(zone)) {
1878		zone_pcp_reset(zone);
1879		mutex_lock(&zonelists_mutex);
1880		build_all_zonelists(NULL, NULL);
1881		mutex_unlock(&zonelists_mutex);
1882	} else
1883		zone_pcp_update(zone);
1884
1885	node_states_clear_node(node, &arg);
1886	if (arg.status_change_nid >= 0) {
1887		kswapd_stop(node);
1888		kcompactd_stop(node);
1889	}
1890
1891	vm_total_pages = nr_free_pagecache_pages();
1892	writeback_set_ratelimit();
1893
1894	memory_notify(MEM_OFFLINE, &arg);
1895	return 0;
1896
1897failed_removal:
1898	pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n",
1899		 (unsigned long long) start_pfn << PAGE_SHIFT,
1900		 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1901	memory_notify(MEM_CANCEL_OFFLINE, &arg);
1902	/* pushback to free area */
1903	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1904	return ret;
1905}
1906
1907/* Must be protected by mem_hotplug_begin() */
1908int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1909{
1910	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1911}
1912#endif /* CONFIG_MEMORY_HOTREMOVE */
1913
1914/**
1915 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1916 * @start_pfn: start pfn of the memory range
1917 * @end_pfn: end pfn of the memory range
1918 * @arg: argument passed to func
1919 * @func: callback for each memory section walked
1920 *
1921 * This function walks through all present mem sections in range
1922 * [start_pfn, end_pfn) and call func on each mem section.
1923 *
1924 * Returns the return value of func.
1925 */
1926int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1927		void *arg, int (*func)(struct memory_block *, void *))
1928{
1929	struct memory_block *mem = NULL;
1930	struct mem_section *section;
1931	unsigned long pfn, section_nr;
1932	int ret;
1933
1934	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1935		section_nr = pfn_to_section_nr(pfn);
1936		if (!present_section_nr(section_nr))
1937			continue;
1938
1939		section = __nr_to_section(section_nr);
1940		/* same memblock? */
1941		if (mem)
1942			if ((section_nr >= mem->start_section_nr) &&
1943			    (section_nr <= mem->end_section_nr))
1944				continue;
1945
1946		mem = find_memory_block_hinted(section, mem);
1947		if (!mem)
1948			continue;
1949
1950		ret = func(mem, arg);
1951		if (ret) {
1952			kobject_put(&mem->dev.kobj);
1953			return ret;
1954		}
1955	}
1956
1957	if (mem)
1958		kobject_put(&mem->dev.kobj);
1959
1960	return 0;
1961}
1962
1963#ifdef CONFIG_MEMORY_HOTREMOVE
1964static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1965{
1966	int ret = !is_memblock_offlined(mem);
1967
1968	if (unlikely(ret)) {
1969		phys_addr_t beginpa, endpa;
1970
1971		beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1972		endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1973		pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1974			&beginpa, &endpa);
1975	}
1976
1977	return ret;
1978}
1979
1980static int check_cpu_on_node(pg_data_t *pgdat)
1981{
1982	int cpu;
1983
1984	for_each_present_cpu(cpu) {
1985		if (cpu_to_node(cpu) == pgdat->node_id)
1986			/*
1987			 * the cpu on this node isn't removed, and we can't
1988			 * offline this node.
1989			 */
1990			return -EBUSY;
1991	}
1992
1993	return 0;
1994}
1995
1996static void unmap_cpu_on_node(pg_data_t *pgdat)
1997{
1998#ifdef CONFIG_ACPI_NUMA
1999	int cpu;
2000
2001	for_each_possible_cpu(cpu)
2002		if (cpu_to_node(cpu) == pgdat->node_id)
2003			numa_clear_node(cpu);
2004#endif
2005}
2006
2007static int check_and_unmap_cpu_on_node(pg_data_t *pgdat)
2008{
2009	int ret;
2010
2011	ret = check_cpu_on_node(pgdat);
2012	if (ret)
2013		return ret;
2014
2015	/*
2016	 * the node will be offlined when we come here, so we can clear
2017	 * the cpu_to_node() now.
2018	 */
2019
2020	unmap_cpu_on_node(pgdat);
2021	return 0;
2022}
2023
2024/**
2025 * try_offline_node
2026 *
2027 * Offline a node if all memory sections and cpus of the node are removed.
2028 *
2029 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2030 * and online/offline operations before this call.
2031 */
2032void try_offline_node(int nid)
2033{
2034	pg_data_t *pgdat = NODE_DATA(nid);
2035	unsigned long start_pfn = pgdat->node_start_pfn;
2036	unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
2037	unsigned long pfn;
2038	int i;
2039
2040	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
2041		unsigned long section_nr = pfn_to_section_nr(pfn);
2042
2043		if (!present_section_nr(section_nr))
2044			continue;
2045
2046		if (pfn_to_nid(pfn) != nid)
2047			continue;
2048
2049		/*
2050		 * some memory sections of this node are not removed, and we
2051		 * can't offline node now.
2052		 */
2053		return;
2054	}
2055
2056	if (check_and_unmap_cpu_on_node(pgdat))
2057		return;
2058
2059	/*
2060	 * all memory/cpu of this node are removed, we can offline this
2061	 * node now.
2062	 */
2063	node_set_offline(nid);
2064	unregister_one_node(nid);
2065
2066	/* free waittable in each zone */
2067	for (i = 0; i < MAX_NR_ZONES; i++) {
2068		struct zone *zone = pgdat->node_zones + i;
2069
2070		/*
2071		 * wait_table may be allocated from boot memory,
2072		 * here only free if it's allocated by vmalloc.
2073		 */
2074		if (is_vmalloc_addr(zone->wait_table)) {
2075			vfree(zone->wait_table);
2076			zone->wait_table = NULL;
2077		}
2078	}
2079}
2080EXPORT_SYMBOL(try_offline_node);
2081
2082/**
2083 * remove_memory
2084 *
2085 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2086 * and online/offline operations before this call, as required by
2087 * try_offline_node().
2088 */
2089void __ref remove_memory(int nid, u64 start, u64 size)
2090{
2091	int ret;
2092
2093	BUG_ON(check_hotplug_memory_range(start, size));
2094
2095	mem_hotplug_begin();
2096
2097	/*
2098	 * All memory blocks must be offlined before removing memory.  Check
2099	 * whether all memory blocks in question are offline and trigger a BUG()
2100	 * if this is not the case.
2101	 */
2102	ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
2103				check_memblock_offlined_cb);
2104	if (ret)
2105		BUG();
2106
2107	/* remove memmap entry */
2108	firmware_map_remove(start, start + size, "System RAM");
2109	memblock_free(start, size);
2110	memblock_remove(start, size);
2111
2112	arch_remove_memory(start, size);
2113
2114	try_offline_node(nid);
2115
2116	mem_hotplug_done();
2117}
2118EXPORT_SYMBOL_GPL(remove_memory);
2119#endif /* CONFIG_MEMORY_HOTREMOVE */