include/linux/mmzone.h

   1 #ifndef _LINUX_MMZONE_H
   2 #define _LINUX_MMZONE_H
   3
   4 #ifdef __KERNEL__
   5 #ifndef __ASSEMBLY__
   6
   7 #include <linux/config.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/list.h>
  10 #include <linux/wait.h>
  11 #include <linux/cache.h>
  12 #include <linux/threads.h>
  13 #include <linux/numa.h>
  14 #include <linux/init.h>
  15 #include <linux/seqlock.h>
  16 #include <linux/nodemask.h>
  17 #include <asm/atomic.h>
  18 #include <asm/page.h>
  19
  20 /* Free memory management - zoned buddy allocator.  */
  21 #ifndef CONFIG_FORCE_MAX_ZONEORDER
  22 #define MAX_ORDER 11
  23 #else
  24 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
  25 #endif
  26 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
  27
  28 struct free_area {
  29         struct list_head        free_list;
  30         unsigned long           nr_free;
  31 };
  32
  33 struct pglist_data;
  34
  35 /*
  36  * zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
  37  * So add a wild amount of padding here to ensure that they fall into separate
  38  * cachelines.  There are very few zone structures in the machine, so space
  39  * consumption is not a concern here.
  40  */
  41 #if defined(CONFIG_SMP)
  42 struct zone_padding {
  43         char x[0];
  44 } ____cacheline_internodealigned_in_smp;
  45 #define ZONE_PADDING(name)      struct zone_padding name;
  46 #else
  47 #define ZONE_PADDING(name)
  48 #endif
  49
  50 struct per_cpu_pages {
  51         int count;              /* number of pages in the list */
  52         int high;               /* high watermark, emptying needed */
  53         int batch;              /* chunk size for buddy add/remove */
  54         struct list_head list;  /* the list of pages */
  55 };
  56
  57 struct per_cpu_pageset {
  58         struct per_cpu_pages pcp[2];    /* 0: hot.  1: cold */
  59 #ifdef CONFIG_NUMA
  60         unsigned long numa_hit;         /* allocated in intended node */
  61         unsigned long numa_miss;        /* allocated in non intended node */
  62         unsigned long numa_foreign;     /* was intended here, hit elsewhere */
  63         unsigned long interleave_hit;   /* interleaver prefered this zone */
  64         unsigned long local_node;       /* allocation from local node */
  65         unsigned long other_node;       /* allocation from other node */
  66 #endif
  67 } ____cacheline_aligned_in_smp;
  68
  69 #ifdef CONFIG_NUMA
  70 #define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)])
  71 #else
  72 #define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])
  73 #endif
  74
  75 #define ZONE_DMA                0
  76 #define ZONE_DMA32              1
  77 #define ZONE_NORMAL             2
  78 #define ZONE_HIGHMEM            3
  79
  80 #define MAX_NR_ZONES            4       /* Sync this with ZONES_SHIFT */
  81 #define ZONES_SHIFT             2       /* ceil(log2(MAX_NR_ZONES)) */
  82
  83
  84 /*
  85  * When a memory allocation must conform to specific limitations (such
  86  * as being suitable for DMA) the caller will pass in hints to the
  87  * allocator in the gfp_mask, in the zone modifier bits.  These bits
  88  * are used to select a priority ordered list of memory zones which
  89  * match the requested limits.  GFP_ZONEMASK defines which bits within
  90  * the gfp_mask should be considered as zone modifiers.  Each valid
  91  * combination of the zone modifier bits has a corresponding list
  92  * of zones (in node_zonelists).  Thus for two zone modifiers there
  93  * will be a maximum of 4 (2 ** 2) zonelists, for 3 modifiers there will
  94  * be 8 (2 ** 3) zonelists.  GFP_ZONETYPES defines the number of possible
  95  * combinations of zone modifiers in "zone modifier space".
  96  *
  97  * As an optimisation any zone modifier bits which are only valid when
  98  * no other zone modifier bits are set (loners) should be placed in
  99  * the highest order bits of this field.  This allows us to reduce the
 100  * extent of the zonelists thus saving space.  For example in the case
 101  * of three zone modifier bits, we could require up to eight zonelists.
 102  * If the left most zone modifier is a "loner" then the highest valid
 103  * zonelist would be four allowing us to allocate only five zonelists.
 104  * Use the first form for GFP_ZONETYPES when the left most bit is not
 105  * a "loner", otherwise use the second.
 106  *
 107  * NOTE! Make sure this matches the zones in <linux/gfp.h>
 108  */
 109 #define GFP_ZONEMASK    0x07
 110 /* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */
 111 #define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */
 112
 113 /*
 114  * On machines where it is needed (eg PCs) we divide physical memory
 115  * into multiple physical zones. On a 32bit PC we have 4 zones:
 116  *
 117  * ZONE_DMA       < 16 MB       ISA DMA capable memory
 118  * ZONE_DMA32        0 MB       Empty
 119  * ZONE_NORMAL  16-896 MB       direct mapped by the kernel
 120  * ZONE_HIGHMEM  > 896 MB       only page cache and user processes
 121  */
 122
 123 struct zone {
 124         /* Fields commonly accessed by the page allocator */
 125         unsigned long           free_pages;
 126         unsigned long           pages_min, pages_low, pages_high;
 127         /*
 128          * We don't know if the memory that we're going to allocate will be freeable
 129          * or/and it will be released eventually, so to avoid totally wasting several
 130          * GB of ram we must reserve some of the lower zone memory (otherwise we risk
 131          * to run OOM on the lower zones despite there's tons of freeable ram
 132          * on the higher zones). This array is recalculated at runtime if the
 133          * sysctl_lowmem_reserve_ratio sysctl changes.
 134          */
 135         unsigned long           lowmem_reserve[MAX_NR_ZONES];
 136
 137 #ifdef CONFIG_NUMA
 138         struct per_cpu_pageset  *pageset[NR_CPUS];
 139 #else
 140         struct per_cpu_pageset  pageset[NR_CPUS];
 141 #endif
 142         /*
 143          * free areas of different sizes
 144          */
 145         spinlock_t              lock;
 146 #ifdef CONFIG_MEMORY_HOTPLUG
 147         /* see spanned/present_pages for more description */
 148         seqlock_t               span_seqlock;
 149 #endif
 150         struct free_area        free_area[MAX_ORDER];
 151
 152
 153         ZONE_PADDING(_pad1_)
 154
 155         /* Fields commonly accessed by the page reclaim scanner */
 156         spinlock_t              lru_lock;
 157         struct list_head        active_list;
 158         struct list_head        inactive_list;
 159         unsigned long           nr_scan_active;
 160         unsigned long           nr_scan_inactive;
 161         unsigned long           nr_active;
 162         unsigned long           nr_inactive;
 163         unsigned long           pages_scanned;     /* since last reclaim */
 164         int                     all_unreclaimable; /* All pages pinned */
 165
 166         /* A count of how many reclaimers are scanning this zone */
 167         atomic_t                reclaim_in_progress;
 168
 169         /*
 170          * timestamp (in jiffies) of the last zone reclaim that did not
 171          * result in freeing of pages. This is used to avoid repeated scans
 172          * if all memory in the zone is in use.
 173          */
 174         unsigned long           last_unsuccessful_zone_reclaim;
 175
 176         /*
 177          * prev_priority holds the scanning priority for this zone.  It is
 178          * defined as the scanning priority at which we achieved our reclaim
 179          * target at the previous try_to_free_pages() or balance_pgdat()
 180          * invokation.
 181          *
 182          * We use prev_priority as a measure of how much stress page reclaim is
 183          * under - it drives the swappiness decision: whether to unmap mapped
 184          * pages.
 185          *
 186          * temp_priority is used to remember the scanning priority at which
 187          * this zone was successfully refilled to free_pages == pages_high.
 188          *
 189          * Access to both these fields is quite racy even on uniprocessor.  But
 190          * it is expected to average out OK.
 191          */
 192         int temp_priority;
 193         int prev_priority;
 194
 195
 196         ZONE_PADDING(_pad2_)
 197         /* Rarely used or read-mostly fields */
 198
 199         /*
 200          * wait_table           -- the array holding the hash table
 201          * wait_table_size      -- the size of the hash table array
 202          * wait_table_bits      -- wait_table_size == (1 << wait_table_bits)
 203          *
 204          * The purpose of all these is to keep track of the people
 205          * waiting for a page to become available and make them
 206          * runnable again when possible. The trouble is that this
 207          * consumes a lot of space, especially when so few things
 208          * wait on pages at a given time. So instead of using
 209          * per-page waitqueues, we use a waitqueue hash table.
 210          *
 211          * The bucket discipline is to sleep on the same queue when
 212          * colliding and wake all in that wait queue when removing.
 213          * When something wakes, it must check to be sure its page is
 214          * truly available, a la thundering herd. The cost of a
 215          * collision is great, but given the expected load of the
 216          * table, they should be so rare as to be outweighed by the
 217          * benefits from the saved space.
 218          *
 219          * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
 220          * primary users of these fields, and in mm/page_alloc.c
 221          * free_area_init_core() performs the initialization of them.
 222          */
 223         wait_queue_head_t       * wait_table;
 224         unsigned long           wait_table_size;
 225         unsigned long           wait_table_bits;
 226
 227         /*
 228          * Discontig memory support fields.
 229          */
 230         struct pglist_data      *zone_pgdat;
 231         /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
 232         unsigned long           zone_start_pfn;
 233
 234         /*
 235          * zone_start_pfn, spanned_pages and present_pages are all
 236          * protected by span_seqlock.  It is a seqlock because it has
 237          * to be read outside of zone->lock, and it is done in the main
 238          * allocator path.  But, it is written quite infrequently.
 239          *
 240          * The lock is declared along with zone->lock because it is
 241          * frequently read in proximity to zone->lock.  It's good to
 242          * give them a chance of being in the same cacheline.
 243          */
 244         unsigned long           spanned_pages;  /* total size, including holes */
 245         unsigned long           present_pages;  /* amount of memory (excluding holes) */
 246
 247         /*
 248          * rarely used fields:
 249          */
 250         char                    *name;
 251 } ____cacheline_internodealigned_in_smp;
 252
 253
 254 /*
 255  * The "priority" of VM scanning is how much of the queues we will scan in one
 256  * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
 257  * queues ("queue_length >> 12") during an aging round.
 258  */
 259 #define DEF_PRIORITY 12
 260
 261 /*
 262  * One allocation request operates on a zonelist. A zonelist
 263  * is a list of zones, the first one is the 'goal' of the
 264  * allocation, the other zones are fallback zones, in decreasing
 265  * priority.
 266  *
 267  * Right now a zonelist takes up less than a cacheline. We never
 268  * modify it apart from boot-up, and only a few indices are used,
 269  * so despite the zonelist table being relatively big, the cache
 270  * footprint of this construct is very small.
 271  */
 272 struct zonelist {
 273         struct zone *zones[MAX_NUMNODES * MAX_NR_ZONES + 1]; // NULL delimited
 274 };
 275
 276
 277 /*
 278  * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
 279  * (mostly NUMA machines?) to denote a higher-level memory zone than the
 280  * zone denotes.
 281  *
 282  * On NUMA machines, each NUMA node would have a pg_data_t to describe
 283  * it's memory layout.
 284  *
 285  * Memory statistics and page replacement data structures are maintained on a
 286  * per-zone basis.
 287  */
 288 struct bootmem_data;
 289 typedef struct pglist_data {
 290         struct zone node_zones[MAX_NR_ZONES];
 291         struct zonelist node_zonelists[GFP_ZONETYPES];
 292         int nr_zones;
 293 #ifdef CONFIG_FLAT_NODE_MEM_MAP
 294         struct page *node_mem_map;
 295 #endif
 296         struct bootmem_data *bdata;
 297 #ifdef CONFIG_MEMORY_HOTPLUG
 298         /*
 299          * Must be held any time you expect node_start_pfn, node_present_pages
 300          * or node_spanned_pages stay constant.  Holding this will also
 301          * guarantee that any pfn_valid() stays that way.
 302          *
 303          * Nests above zone->lock and zone->size_seqlock.
 304          */
 305         spinlock_t node_size_lock;
 306 #endif
 307         unsigned long node_start_pfn;
 308         unsigned long node_present_pages; /* total number of physical pages */
 309         unsigned long node_spanned_pages; /* total size of physical page
 310                                              range, including holes */
 311         int node_id;
 312         wait_queue_head_t kswapd_wait;
 313         struct task_struct *kswapd;
 314         int kswapd_max_order;
 315 } pg_data_t;
 316
 317 #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
 318 #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
 319 #ifdef CONFIG_FLAT_NODE_MEM_MAP
 320 #define pgdat_page_nr(pgdat, pagenr)    ((pgdat)->node_mem_map + (pagenr))
 321 #else
 322 #define pgdat_page_nr(pgdat, pagenr)    pfn_to_page((pgdat)->node_start_pfn + (pagenr))
 323 #endif
 324 #define nid_page_nr(nid, pagenr)        pgdat_page_nr(NODE_DATA(nid),(pagenr))
 325
 326 #include <linux/memory_hotplug.h>
 327
 328 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
 329                         unsigned long *free, struct pglist_data *pgdat);
 330 void get_zone_counts(unsigned long *active, unsigned long *inactive,
 331                         unsigned long *free);
 332 void build_all_zonelists(void);
 333 void wakeup_kswapd(struct zone *zone, int order);
 334 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
 335                 int classzone_idx, int alloc_flags);
 336
 337 #ifdef CONFIG_HAVE_MEMORY_PRESENT
 338 void memory_present(int nid, unsigned long start, unsigned long end);
 339 #else
 340 static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
 341 #endif
 342
 343 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
 344 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
 345 #endif
 346
 347 /*
 348  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
 349  */
 350 #define zone_idx(zone)          ((zone) - (zone)->zone_pgdat->node_zones)
 351
 352 static inline int populated_zone(struct zone *zone)
 353 {
 354         return (!!zone->present_pages);
 355 }
 356
 357 static inline int is_highmem_idx(int idx)
 358 {
 359         return (idx == ZONE_HIGHMEM);
 360 }
 361
 362 static inline int is_normal_idx(int idx)
 363 {
 364         return (idx == ZONE_NORMAL);
 365 }
 366
 367 /**
 368  * is_highmem - helper function to quickly check if a struct zone is a
 369  *              highmem zone or not.  This is an attempt to keep references
 370  *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
 371  * @zone - pointer to struct zone variable
 372  */
 373 static inline int is_highmem(struct zone *zone)
 374 {
 375         return zone == zone->zone_pgdat->node_zones + ZONE_HIGHMEM;
 376 }
 377
 378 static inline int is_normal(struct zone *zone)
 379 {
 380         return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
 381 }
 382
 383 static inline int is_dma32(struct zone *zone)
 384 {
 385         return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
 386 }
 387
 388 static inline int is_dma(struct zone *zone)
 389 {
 390         return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
 391 }
 392
 393 /* These two functions are used to setup the per zone pages min values */
 394 struct ctl_table;
 395 struct file;
 396 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *,
 397                                         void __user *, size_t *, loff_t *);
 398 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
 399 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *,
 400                                         void __user *, size_t *, loff_t *);
 401 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file *,
 402                                         void __user *, size_t *, loff_t *);
 403
 404 #include <linux/topology.h>
 405 /* Returns the number of the current Node. */
 406 #ifndef numa_node_id
 407 #define numa_node_id()          (cpu_to_node(raw_smp_processor_id()))
 408 #endif
 409
 410 #ifndef CONFIG_NEED_MULTIPLE_NODES
 411
 412 extern struct pglist_data contig_page_data;
 413 #define NODE_DATA(nid)          (&contig_page_data)
 414 #define NODE_MEM_MAP(nid)       mem_map
 415 #define MAX_NODES_SHIFT         1
 416
 417 #else /* CONFIG_NEED_MULTIPLE_NODES */
 418
 419 #include <asm/mmzone.h>
 420
 421 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 422
 423 extern struct pglist_data *first_online_pgdat(void);
 424 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
 425 extern struct zone *next_zone(struct zone *zone);
 426
 427 /**
 428  * for_each_pgdat - helper macro to iterate over all nodes
 429  * @pgdat - pointer to a pg_data_t variable
 430  */
 431 #define for_each_online_pgdat(pgdat)                    \
 432         for (pgdat = first_online_pgdat();              \
 433              pgdat;                                     \
 434              pgdat = next_online_pgdat(pgdat))
 435 /**
 436  * for_each_zone - helper macro to iterate over all memory zones
 437  * @zone - pointer to struct zone variable
 438  *
 439  * The user only needs to declare the zone variable, for_each_zone
 440  * fills it in.
 441  */
 442 #define for_each_zone(zone)                             \
 443         for (zone = (first_online_pgdat())->node_zones; \
 444              zone;                                      \
 445              zone = next_zone(zone))
 446
 447 #ifdef CONFIG_SPARSEMEM
 448 #include <asm/sparsemem.h>
 449 #endif
 450
 451 #if BITS_PER_LONG == 32
 452 /*
 453  * with 32 bit page->flags field, we reserve 9 bits for node/zone info.
 454  * there are 4 zones (3 bits) and this leaves 9-3=6 bits for nodes.
 455  */
 456 #define FLAGS_RESERVED          9
 457
 458 #elif BITS_PER_LONG == 64
 459 /*
 460  * with 64 bit flags field, there's plenty of room.
 461  */
 462 #define FLAGS_RESERVED          32
 463
 464 #else
 465
 466 #error BITS_PER_LONG not defined
 467
 468 #endif
 469
 470 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
 471 #define early_pfn_to_nid(nid)  (0UL)
 472 #endif
 473
 474 #ifdef CONFIG_FLATMEM
 475 #define pfn_to_nid(pfn)         (0)
 476 #endif
 477
 478 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
 479 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
 480
 481 #ifdef CONFIG_SPARSEMEM
 482
 483 /*
 484  * SECTION_SHIFT                #bits space required to store a section #
 485  *
 486  * PA_SECTION_SHIFT             physical address to/from section number
 487  * PFN_SECTION_SHIFT            pfn to/from section number
 488  */
 489 #define SECTIONS_SHIFT          (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
 490
 491 #define PA_SECTION_SHIFT        (SECTION_SIZE_BITS)
 492 #define PFN_SECTION_SHIFT       (SECTION_SIZE_BITS - PAGE_SHIFT)
 493
 494 #define NR_MEM_SECTIONS         (1UL << SECTIONS_SHIFT)
 495
 496 #define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
 497 #define PAGE_SECTION_MASK       (~(PAGES_PER_SECTION-1))
 498
 499 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
 500 #error Allocator MAX_ORDER exceeds SECTION_SIZE
 501 #endif
 502
 503 struct page;
 504 struct mem_section {
 505         /*
 506          * This is, logically, a pointer to an array of struct
 507          * pages.  However, it is stored with some other magic.
 508          * (see sparse.c::sparse_init_one_section())
 509          *
 510          * Making it a UL at least makes someone do a cast
 511          * before using it wrong.
 512          */
 513         unsigned long section_mem_map;
 514 };
 515
 516 #ifdef CONFIG_SPARSEMEM_EXTREME
 517 #define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
 518 #else
 519 #define SECTIONS_PER_ROOT       1
 520 #endif
 521
 522 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
 523 #define NR_SECTION_ROOTS        (NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
 524 #define SECTION_ROOT_MASK       (SECTIONS_PER_ROOT - 1)
 525
 526 #ifdef CONFIG_SPARSEMEM_EXTREME
 527 extern struct mem_section *mem_section[NR_SECTION_ROOTS];
 528 #else
 529 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
 530 #endif
 531
 532 static inline struct mem_section *__nr_to_section(unsigned long nr)
 533 {
 534         if (!mem_section[SECTION_NR_TO_ROOT(nr)])
 535                 return NULL;
 536         return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
 537 }
 538 extern int __section_nr(struct mem_section* ms);
 539
 540 /*
 541  * We use the lower bits of the mem_map pointer to store
 542  * a little bit of information.  There should be at least
 543  * 3 bits here due to 32-bit alignment.
 544  */
 545 #define SECTION_MARKED_PRESENT  (1UL<<0)
 546 #define SECTION_HAS_MEM_MAP     (1UL<<1)
 547 #define SECTION_MAP_LAST_BIT    (1UL<<2)
 548 #define SECTION_MAP_MASK        (~(SECTION_MAP_LAST_BIT-1))
 549
 550 static inline struct page *__section_mem_map_addr(struct mem_section *section)
 551 {
 552         unsigned long map = section->section_mem_map;
 553         map &= SECTION_MAP_MASK;
 554         return (struct page *)map;
 555 }
 556
 557 static inline int valid_section(struct mem_section *section)
 558 {
 559         return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
 560 }
 561
 562 static inline int section_has_mem_map(struct mem_section *section)
 563 {
 564         return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
 565 }
 566
 567 static inline int valid_section_nr(unsigned long nr)
 568 {
 569         return valid_section(__nr_to_section(nr));
 570 }
 571
 572 static inline struct mem_section *__pfn_to_section(unsigned long pfn)
 573 {
 574         return __nr_to_section(pfn_to_section_nr(pfn));
 575 }
 576
 577 static inline int pfn_valid(unsigned long pfn)
 578 {
 579         if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
 580                 return 0;
 581         return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
 582 }
 583
 584 /*
 585  * These are _only_ used during initialisation, therefore they
 586  * can use __initdata ...  They could have names to indicate
 587  * this restriction.
 588  */
 589 #ifdef CONFIG_NUMA
 590 #define pfn_to_nid(pfn)                                                 \
 591 ({                                                                      \
 592         unsigned long __pfn_to_nid_pfn = (pfn);                         \
 593         page_to_nid(pfn_to_page(__pfn_to_nid_pfn));                     \
 594 })
 595 #else
 596 #define pfn_to_nid(pfn)         (0)
 597 #endif
 598
 599 #define early_pfn_valid(pfn)    pfn_valid(pfn)
 600 void sparse_init(void);
 601 #else
 602 #define sparse_init()   do {} while (0)
 603 #define sparse_index_init(_sec, _nid)  do {} while (0)
 604 #endif /* CONFIG_SPARSEMEM */
 605
 606 #ifndef early_pfn_valid
 607 #define early_pfn_valid(pfn)    (1)
 608 #endif
 609
 610 void memory_present(int nid, unsigned long start, unsigned long end);
 611 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
 612
 613 #endif /* !__ASSEMBLY__ */
 614 #endif /* __KERNEL__ */
 615 #endif /* _LINUX_MMZONE_H */