linux/include/linux/mmzone.h
<<
>>
Prefs
   1#ifndef _LINUX_MMZONE_H
   2#define _LINUX_MMZONE_H
   3
   4#ifndef __ASSEMBLY__
   5#ifndef __GENERATING_BOUNDS_H
   6
   7#include <linux/spinlock.h>
   8#include <linux/list.h>
   9#include <linux/wait.h>
  10#include <linux/bitops.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 <linux/pageblock-flags.h>
  18#include <linux/bounds.h>
  19#include <asm/atomic.h>
  20#include <asm/page.h>
  21
  22/* Free memory management - zoned buddy allocator.  */
  23#ifndef CONFIG_FORCE_MAX_ZONEORDER
  24#define MAX_ORDER 11
  25#else
  26#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
  27#endif
  28#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
  29
  30/*
  31 * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
  32 * costly to service.  That is between allocation orders which should
  33 * coelesce naturally under reasonable reclaim pressure and those which
  34 * will not.
  35 */
  36#define PAGE_ALLOC_COSTLY_ORDER 3
  37
  38#define MIGRATE_UNMOVABLE     0
  39#define MIGRATE_RECLAIMABLE   1
  40#define MIGRATE_MOVABLE       2
  41#define MIGRATE_PCPTYPES      3 /* the number of types on the pcp lists */
  42#define MIGRATE_RESERVE       3
  43#define MIGRATE_ISOLATE       4 /* can't allocate from here */
  44#define MIGRATE_TYPES         5
  45
  46#define for_each_migratetype_order(order, type) \
  47        for (order = 0; order < MAX_ORDER; order++) \
  48                for (type = 0; type < MIGRATE_TYPES; type++)
  49
  50extern int page_group_by_mobility_disabled;
  51
  52static inline int get_pageblock_migratetype(struct page *page)
  53{
  54        return get_pageblock_flags_group(page, PB_migrate, PB_migrate_end);
  55}
  56
  57struct free_area {
  58        struct list_head        free_list[MIGRATE_TYPES];
  59        unsigned long           nr_free;
  60};
  61
  62struct pglist_data;
  63
  64/*
  65 * zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
  66 * So add a wild amount of padding here to ensure that they fall into separate
  67 * cachelines.  There are very few zone structures in the machine, so space
  68 * consumption is not a concern here.
  69 */
  70#if defined(CONFIG_SMP)
  71struct zone_padding {
  72        char x[0];
  73} ____cacheline_internodealigned_in_smp;
  74#define ZONE_PADDING(name)      struct zone_padding name;
  75#else
  76#define ZONE_PADDING(name)
  77#endif
  78
  79enum zone_stat_item {
  80        /* First 128 byte cacheline (assuming 64 bit words) */
  81        NR_FREE_PAGES,
  82        NR_LRU_BASE,
  83        NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
  84        NR_ACTIVE_ANON,         /*  "     "     "   "       "         */
  85        NR_INACTIVE_FILE,       /*  "     "     "   "       "         */
  86        NR_ACTIVE_FILE,         /*  "     "     "   "       "         */
  87        NR_UNEVICTABLE,         /*  "     "     "   "       "         */
  88        NR_MLOCK,               /* mlock()ed pages found and moved off LRU */
  89        NR_ANON_PAGES,  /* Mapped anonymous pages */
  90        NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
  91                           only modified from process context */
  92        NR_FILE_PAGES,
  93        NR_FILE_DIRTY,
  94        NR_WRITEBACK,
  95        NR_SLAB_RECLAIMABLE,
  96        NR_SLAB_UNRECLAIMABLE,
  97        NR_PAGETABLE,           /* used for pagetables */
  98        NR_KERNEL_STACK,
  99        /* Second 128 byte cacheline */
 100        NR_UNSTABLE_NFS,        /* NFS unstable pages */
 101        NR_BOUNCE,
 102        NR_VMSCAN_WRITE,
 103        NR_WRITEBACK_TEMP,      /* Writeback using temporary buffers */
 104        NR_ISOLATED_ANON,       /* Temporary isolated pages from anon lru */
 105        NR_ISOLATED_FILE,       /* Temporary isolated pages from file lru */
 106        NR_SHMEM,               /* shmem pages (included tmpfs/GEM pages) */
 107#ifdef CONFIG_NUMA
 108        NUMA_HIT,               /* allocated in intended node */
 109        NUMA_MISS,              /* allocated in non intended node */
 110        NUMA_FOREIGN,           /* was intended here, hit elsewhere */
 111        NUMA_INTERLEAVE_HIT,    /* interleaver preferred this zone */
 112        NUMA_LOCAL,             /* allocation from local node */
 113        NUMA_OTHER,             /* allocation from other node */
 114#endif
 115        NR_VM_ZONE_STAT_ITEMS };
 116
 117/*
 118 * We do arithmetic on the LRU lists in various places in the code,
 119 * so it is important to keep the active lists LRU_ACTIVE higher in
 120 * the array than the corresponding inactive lists, and to keep
 121 * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
 122 *
 123 * This has to be kept in sync with the statistics in zone_stat_item
 124 * above and the descriptions in vmstat_text in mm/vmstat.c
 125 */
 126#define LRU_BASE 0
 127#define LRU_ACTIVE 1
 128#define LRU_FILE 2
 129
 130enum lru_list {
 131        LRU_INACTIVE_ANON = LRU_BASE,
 132        LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
 133        LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
 134        LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
 135        LRU_UNEVICTABLE,
 136        NR_LRU_LISTS
 137};
 138
 139#define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
 140
 141#define for_each_evictable_lru(l) for (l = 0; l <= LRU_ACTIVE_FILE; l++)
 142
 143static inline int is_file_lru(enum lru_list l)
 144{
 145        return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
 146}
 147
 148static inline int is_active_lru(enum lru_list l)
 149{
 150        return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
 151}
 152
 153static inline int is_unevictable_lru(enum lru_list l)
 154{
 155        return (l == LRU_UNEVICTABLE);
 156}
 157
 158enum zone_watermarks {
 159        WMARK_MIN,
 160        WMARK_LOW,
 161        WMARK_HIGH,
 162        NR_WMARK
 163};
 164
 165#define min_wmark_pages(z) (z->watermark[WMARK_MIN])
 166#define low_wmark_pages(z) (z->watermark[WMARK_LOW])
 167#define high_wmark_pages(z) (z->watermark[WMARK_HIGH])
 168
 169struct per_cpu_pages {
 170        int count;              /* number of pages in the list */
 171        int high;               /* high watermark, emptying needed */
 172        int batch;              /* chunk size for buddy add/remove */
 173
 174        /* Lists of pages, one per migrate type stored on the pcp-lists */
 175        struct list_head lists[MIGRATE_PCPTYPES];
 176};
 177
 178struct per_cpu_pageset {
 179        struct per_cpu_pages pcp;
 180#ifdef CONFIG_NUMA
 181        s8 expire;
 182#endif
 183#ifdef CONFIG_SMP
 184        s8 stat_threshold;
 185        s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
 186#endif
 187} ____cacheline_aligned_in_smp;
 188
 189#ifdef CONFIG_NUMA
 190#define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)])
 191#else
 192#define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])
 193#endif
 194
 195#endif /* !__GENERATING_BOUNDS.H */
 196
 197enum zone_type {
 198#ifdef CONFIG_ZONE_DMA
 199        /*
 200         * ZONE_DMA is used when there are devices that are not able
 201         * to do DMA to all of addressable memory (ZONE_NORMAL). Then we
 202         * carve out the portion of memory that is needed for these devices.
 203         * The range is arch specific.
 204         *
 205         * Some examples
 206         *
 207         * Architecture         Limit
 208         * ---------------------------
 209         * parisc, ia64, sparc  <4G
 210         * s390                 <2G
 211         * arm                  Various
 212         * alpha                Unlimited or 0-16MB.
 213         *
 214         * i386, x86_64 and multiple other arches
 215         *                      <16M.
 216         */
 217        ZONE_DMA,
 218#endif
 219#ifdef CONFIG_ZONE_DMA32
 220        /*
 221         * x86_64 needs two ZONE_DMAs because it supports devices that are
 222         * only able to do DMA to the lower 16M but also 32 bit devices that
 223         * can only do DMA areas below 4G.
 224         */
 225        ZONE_DMA32,
 226#endif
 227        /*
 228         * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
 229         * performed on pages in ZONE_NORMAL if the DMA devices support
 230         * transfers to all addressable memory.
 231         */
 232        ZONE_NORMAL,
 233#ifdef CONFIG_HIGHMEM
 234        /*
 235         * A memory area that is only addressable by the kernel through
 236         * mapping portions into its own address space. This is for example
 237         * used by i386 to allow the kernel to address the memory beyond
 238         * 900MB. The kernel will set up special mappings (page
 239         * table entries on i386) for each page that the kernel needs to
 240         * access.
 241         */
 242        ZONE_HIGHMEM,
 243#endif
 244        ZONE_MOVABLE,
 245        __MAX_NR_ZONES
 246};
 247
 248#ifndef __GENERATING_BOUNDS_H
 249
 250/*
 251 * When a memory allocation must conform to specific limitations (such
 252 * as being suitable for DMA) the caller will pass in hints to the
 253 * allocator in the gfp_mask, in the zone modifier bits.  These bits
 254 * are used to select a priority ordered list of memory zones which
 255 * match the requested limits. See gfp_zone() in include/linux/gfp.h
 256 */
 257
 258#if MAX_NR_ZONES < 2
 259#define ZONES_SHIFT 0
 260#elif MAX_NR_ZONES <= 2
 261#define ZONES_SHIFT 1
 262#elif MAX_NR_ZONES <= 4
 263#define ZONES_SHIFT 2
 264#else
 265#error ZONES_SHIFT -- too many zones configured adjust calculation
 266#endif
 267
 268struct zone_reclaim_stat {
 269        /*
 270         * The pageout code in vmscan.c keeps track of how many of the
 271         * mem/swap backed and file backed pages are refeferenced.
 272         * The higher the rotated/scanned ratio, the more valuable
 273         * that cache is.
 274         *
 275         * The anon LRU stats live in [0], file LRU stats in [1]
 276         */
 277        unsigned long           recent_rotated[2];
 278        unsigned long           recent_scanned[2];
 279
 280        /*
 281         * accumulated for batching
 282         */
 283        unsigned long           nr_saved_scan[NR_LRU_LISTS];
 284};
 285
 286struct zone {
 287        /* Fields commonly accessed by the page allocator */
 288
 289        /* zone watermarks, access with *_wmark_pages(zone) macros */
 290        unsigned long watermark[NR_WMARK];
 291
 292        /*
 293         * We don't know if the memory that we're going to allocate will be freeable
 294         * or/and it will be released eventually, so to avoid totally wasting several
 295         * GB of ram we must reserve some of the lower zone memory (otherwise we risk
 296         * to run OOM on the lower zones despite there's tons of freeable ram
 297         * on the higher zones). This array is recalculated at runtime if the
 298         * sysctl_lowmem_reserve_ratio sysctl changes.
 299         */
 300        unsigned long           lowmem_reserve[MAX_NR_ZONES];
 301
 302#ifdef CONFIG_NUMA
 303        int node;
 304        /*
 305         * zone reclaim becomes active if more unmapped pages exist.
 306         */
 307        unsigned long           min_unmapped_pages;
 308        unsigned long           min_slab_pages;
 309        struct per_cpu_pageset  *pageset[NR_CPUS];
 310#else
 311        struct per_cpu_pageset  pageset[NR_CPUS];
 312#endif
 313        /*
 314         * free areas of different sizes
 315         */
 316        spinlock_t              lock;
 317#ifdef CONFIG_MEMORY_HOTPLUG
 318        /* see spanned/present_pages for more description */
 319        seqlock_t               span_seqlock;
 320#endif
 321        struct free_area        free_area[MAX_ORDER];
 322
 323#ifndef CONFIG_SPARSEMEM
 324        /*
 325         * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
 326         * In SPARSEMEM, this map is stored in struct mem_section
 327         */
 328        unsigned long           *pageblock_flags;
 329#endif /* CONFIG_SPARSEMEM */
 330
 331
 332        ZONE_PADDING(_pad1_)
 333
 334        /* Fields commonly accessed by the page reclaim scanner */
 335        spinlock_t              lru_lock;       
 336        struct zone_lru {
 337                struct list_head list;
 338        } lru[NR_LRU_LISTS];
 339
 340        struct zone_reclaim_stat reclaim_stat;
 341
 342        unsigned long           pages_scanned;     /* since last reclaim */
 343        unsigned long           flags;             /* zone flags, see below */
 344
 345        /* Zone statistics */
 346        atomic_long_t           vm_stat[NR_VM_ZONE_STAT_ITEMS];
 347
 348        /*
 349         * prev_priority holds the scanning priority for this zone.  It is
 350         * defined as the scanning priority at which we achieved our reclaim
 351         * target at the previous try_to_free_pages() or balance_pgdat()
 352         * invokation.
 353         *
 354         * We use prev_priority as a measure of how much stress page reclaim is
 355         * under - it drives the swappiness decision: whether to unmap mapped
 356         * pages.
 357         *
 358         * Access to both this field is quite racy even on uniprocessor.  But
 359         * it is expected to average out OK.
 360         */
 361        int prev_priority;
 362
 363        /*
 364         * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
 365         * this zone's LRU.  Maintained by the pageout code.
 366         */
 367        unsigned int inactive_ratio;
 368
 369
 370        ZONE_PADDING(_pad2_)
 371        /* Rarely used or read-mostly fields */
 372
 373        /*
 374         * wait_table           -- the array holding the hash table
 375         * wait_table_hash_nr_entries   -- the size of the hash table array
 376         * wait_table_bits      -- wait_table_size == (1 << wait_table_bits)
 377         *
 378         * The purpose of all these is to keep track of the people
 379         * waiting for a page to become available and make them
 380         * runnable again when possible. The trouble is that this
 381         * consumes a lot of space, especially when so few things
 382         * wait on pages at a given time. So instead of using
 383         * per-page waitqueues, we use a waitqueue hash table.
 384         *
 385         * The bucket discipline is to sleep on the same queue when
 386         * colliding and wake all in that wait queue when removing.
 387         * When something wakes, it must check to be sure its page is
 388         * truly available, a la thundering herd. The cost of a
 389         * collision is great, but given the expected load of the
 390         * table, they should be so rare as to be outweighed by the
 391         * benefits from the saved space.
 392         *
 393         * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
 394         * primary users of these fields, and in mm/page_alloc.c
 395         * free_area_init_core() performs the initialization of them.
 396         */
 397        wait_queue_head_t       * wait_table;
 398        unsigned long           wait_table_hash_nr_entries;
 399        unsigned long           wait_table_bits;
 400
 401        /*
 402         * Discontig memory support fields.
 403         */
 404        struct pglist_data      *zone_pgdat;
 405        /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
 406        unsigned long           zone_start_pfn;
 407
 408        /*
 409         * zone_start_pfn, spanned_pages and present_pages are all
 410         * protected by span_seqlock.  It is a seqlock because it has
 411         * to be read outside of zone->lock, and it is done in the main
 412         * allocator path.  But, it is written quite infrequently.
 413         *
 414         * The lock is declared along with zone->lock because it is
 415         * frequently read in proximity to zone->lock.  It's good to
 416         * give them a chance of being in the same cacheline.
 417         */
 418        unsigned long           spanned_pages;  /* total size, including holes */
 419        unsigned long           present_pages;  /* amount of memory (excluding holes) */
 420
 421        /*
 422         * rarely used fields:
 423         */
 424        const char              *name;
 425} ____cacheline_internodealigned_in_smp;
 426
 427typedef enum {
 428        ZONE_ALL_UNRECLAIMABLE,         /* all pages pinned */
 429        ZONE_RECLAIM_LOCKED,            /* prevents concurrent reclaim */
 430        ZONE_OOM_LOCKED,                /* zone is in OOM killer zonelist */
 431} zone_flags_t;
 432
 433static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
 434{
 435        set_bit(flag, &zone->flags);
 436}
 437
 438static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
 439{
 440        return test_and_set_bit(flag, &zone->flags);
 441}
 442
 443static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
 444{
 445        clear_bit(flag, &zone->flags);
 446}
 447
 448static inline int zone_is_all_unreclaimable(const struct zone *zone)
 449{
 450        return test_bit(ZONE_ALL_UNRECLAIMABLE, &zone->flags);
 451}
 452
 453static inline int zone_is_reclaim_locked(const struct zone *zone)
 454{
 455        return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
 456}
 457
 458static inline int zone_is_oom_locked(const struct zone *zone)
 459{
 460        return test_bit(ZONE_OOM_LOCKED, &zone->flags);
 461}
 462
 463/*
 464 * The "priority" of VM scanning is how much of the queues we will scan in one
 465 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
 466 * queues ("queue_length >> 12") during an aging round.
 467 */
 468#define DEF_PRIORITY 12
 469
 470/* Maximum number of zones on a zonelist */
 471#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
 472
 473#ifdef CONFIG_NUMA
 474
 475/*
 476 * The NUMA zonelists are doubled becausse we need zonelists that restrict the
 477 * allocations to a single node for GFP_THISNODE.
 478 *
 479 * [0]  : Zonelist with fallback
 480 * [1]  : No fallback (GFP_THISNODE)
 481 */
 482#define MAX_ZONELISTS 2
 483
 484
 485/*
 486 * We cache key information from each zonelist for smaller cache
 487 * footprint when scanning for free pages in get_page_from_freelist().
 488 *
 489 * 1) The BITMAP fullzones tracks which zones in a zonelist have come
 490 *    up short of free memory since the last time (last_fullzone_zap)
 491 *    we zero'd fullzones.
 492 * 2) The array z_to_n[] maps each zone in the zonelist to its node
 493 *    id, so that we can efficiently evaluate whether that node is
 494 *    set in the current tasks mems_allowed.
 495 *
 496 * Both fullzones and z_to_n[] are one-to-one with the zonelist,
 497 * indexed by a zones offset in the zonelist zones[] array.
 498 *
 499 * The get_page_from_freelist() routine does two scans.  During the
 500 * first scan, we skip zones whose corresponding bit in 'fullzones'
 501 * is set or whose corresponding node in current->mems_allowed (which
 502 * comes from cpusets) is not set.  During the second scan, we bypass
 503 * this zonelist_cache, to ensure we look methodically at each zone.
 504 *
 505 * Once per second, we zero out (zap) fullzones, forcing us to
 506 * reconsider nodes that might have regained more free memory.
 507 * The field last_full_zap is the time we last zapped fullzones.
 508 *
 509 * This mechanism reduces the amount of time we waste repeatedly
 510 * reexaming zones for free memory when they just came up low on
 511 * memory momentarilly ago.
 512 *
 513 * The zonelist_cache struct members logically belong in struct
 514 * zonelist.  However, the mempolicy zonelists constructed for
 515 * MPOL_BIND are intentionally variable length (and usually much
 516 * shorter).  A general purpose mechanism for handling structs with
 517 * multiple variable length members is more mechanism than we want
 518 * here.  We resort to some special case hackery instead.
 519 *
 520 * The MPOL_BIND zonelists don't need this zonelist_cache (in good
 521 * part because they are shorter), so we put the fixed length stuff
 522 * at the front of the zonelist struct, ending in a variable length
 523 * zones[], as is needed by MPOL_BIND.
 524 *
 525 * Then we put the optional zonelist cache on the end of the zonelist
 526 * struct.  This optional stuff is found by a 'zlcache_ptr' pointer in
 527 * the fixed length portion at the front of the struct.  This pointer
 528 * both enables us to find the zonelist cache, and in the case of
 529 * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL)
 530 * to know that the zonelist cache is not there.
 531 *
 532 * The end result is that struct zonelists come in two flavors:
 533 *  1) The full, fixed length version, shown below, and
 534 *  2) The custom zonelists for MPOL_BIND.
 535 * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache.
 536 *
 537 * Even though there may be multiple CPU cores on a node modifying
 538 * fullzones or last_full_zap in the same zonelist_cache at the same
 539 * time, we don't lock it.  This is just hint data - if it is wrong now
 540 * and then, the allocator will still function, perhaps a bit slower.
 541 */
 542
 543
 544struct zonelist_cache {
 545        unsigned short z_to_n[MAX_ZONES_PER_ZONELIST];          /* zone->nid */
 546        DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST);      /* zone full? */
 547        unsigned long last_full_zap;            /* when last zap'd (jiffies) */
 548};
 549#else
 550#define MAX_ZONELISTS 1
 551struct zonelist_cache;
 552#endif
 553
 554/*
 555 * This struct contains information about a zone in a zonelist. It is stored
 556 * here to avoid dereferences into large structures and lookups of tables
 557 */
 558struct zoneref {
 559        struct zone *zone;      /* Pointer to actual zone */
 560        int zone_idx;           /* zone_idx(zoneref->zone) */
 561};
 562
 563/*
 564 * One allocation request operates on a zonelist. A zonelist
 565 * is a list of zones, the first one is the 'goal' of the
 566 * allocation, the other zones are fallback zones, in decreasing
 567 * priority.
 568 *
 569 * If zlcache_ptr is not NULL, then it is just the address of zlcache,
 570 * as explained above.  If zlcache_ptr is NULL, there is no zlcache.
 571 * *
 572 * To speed the reading of the zonelist, the zonerefs contain the zone index
 573 * of the entry being read. Helper functions to access information given
 574 * a struct zoneref are
 575 *
 576 * zonelist_zone()      - Return the struct zone * for an entry in _zonerefs
 577 * zonelist_zone_idx()  - Return the index of the zone for an entry
 578 * zonelist_node_idx()  - Return the index of the node for an entry
 579 */
 580struct zonelist {
 581        struct zonelist_cache *zlcache_ptr;                  // NULL or &zlcache
 582        struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
 583#ifdef CONFIG_NUMA
 584        struct zonelist_cache zlcache;                       // optional ...
 585#endif
 586};
 587
 588#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
 589struct node_active_region {
 590        unsigned long start_pfn;
 591        unsigned long end_pfn;
 592        int nid;
 593};
 594#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
 595
 596#ifndef CONFIG_DISCONTIGMEM
 597/* The array of struct pages - for discontigmem use pgdat->lmem_map */
 598extern struct page *mem_map;
 599#endif
 600
 601/*
 602 * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
 603 * (mostly NUMA machines?) to denote a higher-level memory zone than the
 604 * zone denotes.
 605 *
 606 * On NUMA machines, each NUMA node would have a pg_data_t to describe
 607 * it's memory layout.
 608 *
 609 * Memory statistics and page replacement data structures are maintained on a
 610 * per-zone basis.
 611 */
 612struct bootmem_data;
 613typedef struct pglist_data {
 614        struct zone node_zones[MAX_NR_ZONES];
 615        struct zonelist node_zonelists[MAX_ZONELISTS];
 616        int nr_zones;
 617#ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
 618        struct page *node_mem_map;
 619#ifdef CONFIG_CGROUP_MEM_RES_CTLR
 620        struct page_cgroup *node_page_cgroup;
 621#endif
 622#endif
 623        struct bootmem_data *bdata;
 624#ifdef CONFIG_MEMORY_HOTPLUG
 625        /*
 626         * Must be held any time you expect node_start_pfn, node_present_pages
 627         * or node_spanned_pages stay constant.  Holding this will also
 628         * guarantee that any pfn_valid() stays that way.
 629         *
 630         * Nests above zone->lock and zone->size_seqlock.
 631         */
 632        spinlock_t node_size_lock;
 633#endif
 634        unsigned long node_start_pfn;
 635        unsigned long node_present_pages; /* total number of physical pages */
 636        unsigned long node_spanned_pages; /* total size of physical page
 637                                             range, including holes */
 638        int node_id;
 639        wait_queue_head_t kswapd_wait;
 640        struct task_struct *kswapd;
 641        int kswapd_max_order;
 642} pg_data_t;
 643
 644#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
 645#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
 646#ifdef CONFIG_FLAT_NODE_MEM_MAP
 647#define pgdat_page_nr(pgdat, pagenr)    ((pgdat)->node_mem_map + (pagenr))
 648#else
 649#define pgdat_page_nr(pgdat, pagenr)    pfn_to_page((pgdat)->node_start_pfn + (pagenr))
 650#endif
 651#define nid_page_nr(nid, pagenr)        pgdat_page_nr(NODE_DATA(nid),(pagenr))
 652
 653#include <linux/memory_hotplug.h>
 654
 655void get_zone_counts(unsigned long *active, unsigned long *inactive,
 656                        unsigned long *free);
 657void build_all_zonelists(void);
 658void wakeup_kswapd(struct zone *zone, int order);
 659int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
 660                int classzone_idx, int alloc_flags);
 661enum memmap_context {
 662        MEMMAP_EARLY,
 663        MEMMAP_HOTPLUG,
 664};
 665extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
 666                                     unsigned long size,
 667                                     enum memmap_context context);
 668
 669#ifdef CONFIG_HAVE_MEMORY_PRESENT
 670void memory_present(int nid, unsigned long start, unsigned long end);
 671#else
 672static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
 673#endif
 674
 675#ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
 676unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
 677#endif
 678
 679/*
 680 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
 681 */
 682#define zone_idx(zone)          ((zone) - (zone)->zone_pgdat->node_zones)
 683
 684static inline int populated_zone(struct zone *zone)
 685{
 686        return (!!zone->present_pages);
 687}
 688
 689extern int movable_zone;
 690
 691static inline int zone_movable_is_highmem(void)
 692{
 693#if defined(CONFIG_HIGHMEM) && defined(CONFIG_ARCH_POPULATES_NODE_MAP)
 694        return movable_zone == ZONE_HIGHMEM;
 695#else
 696        return 0;
 697#endif
 698}
 699
 700static inline int is_highmem_idx(enum zone_type idx)
 701{
 702#ifdef CONFIG_HIGHMEM
 703        return (idx == ZONE_HIGHMEM ||
 704                (idx == ZONE_MOVABLE && zone_movable_is_highmem()));
 705#else
 706        return 0;
 707#endif
 708}
 709
 710static inline int is_normal_idx(enum zone_type idx)
 711{
 712        return (idx == ZONE_NORMAL);
 713}
 714
 715/**
 716 * is_highmem - helper function to quickly check if a struct zone is a 
 717 *              highmem zone or not.  This is an attempt to keep references
 718 *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
 719 * @zone - pointer to struct zone variable
 720 */
 721static inline int is_highmem(struct zone *zone)
 722{
 723#ifdef CONFIG_HIGHMEM
 724        int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
 725        return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
 726               (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
 727                zone_movable_is_highmem());
 728#else
 729        return 0;
 730#endif
 731}
 732
 733static inline int is_normal(struct zone *zone)
 734{
 735        return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
 736}
 737
 738static inline int is_dma32(struct zone *zone)
 739{
 740#ifdef CONFIG_ZONE_DMA32
 741        return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
 742#else
 743        return 0;
 744#endif
 745}
 746
 747static inline int is_dma(struct zone *zone)
 748{
 749#ifdef CONFIG_ZONE_DMA
 750        return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
 751#else
 752        return 0;
 753#endif
 754}
 755
 756/* These two functions are used to setup the per zone pages min values */
 757struct ctl_table;
 758int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
 759                                        void __user *, size_t *, loff_t *);
 760extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
 761int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
 762                                        void __user *, size_t *, loff_t *);
 763int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
 764                                        void __user *, size_t *, loff_t *);
 765int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
 766                        void __user *, size_t *, loff_t *);
 767int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
 768                        void __user *, size_t *, loff_t *);
 769
 770extern int numa_zonelist_order_handler(struct ctl_table *, int,
 771                        void __user *, size_t *, loff_t *);
 772extern char numa_zonelist_order[];
 773#define NUMA_ZONELIST_ORDER_LEN 16      /* string buffer size */
 774
 775#ifndef CONFIG_NEED_MULTIPLE_NODES
 776
 777extern struct pglist_data contig_page_data;
 778#define NODE_DATA(nid)          (&contig_page_data)
 779#define NODE_MEM_MAP(nid)       mem_map
 780
 781#else /* CONFIG_NEED_MULTIPLE_NODES */
 782
 783#include <asm/mmzone.h>
 784
 785#endif /* !CONFIG_NEED_MULTIPLE_NODES */
 786
 787extern struct pglist_data *first_online_pgdat(void);
 788extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
 789extern struct zone *next_zone(struct zone *zone);
 790
 791/**
 792 * for_each_online_pgdat - helper macro to iterate over all online nodes
 793 * @pgdat - pointer to a pg_data_t variable
 794 */
 795#define for_each_online_pgdat(pgdat)                    \
 796        for (pgdat = first_online_pgdat();              \
 797             pgdat;                                     \
 798             pgdat = next_online_pgdat(pgdat))
 799/**
 800 * for_each_zone - helper macro to iterate over all memory zones
 801 * @zone - pointer to struct zone variable
 802 *
 803 * The user only needs to declare the zone variable, for_each_zone
 804 * fills it in.
 805 */
 806#define for_each_zone(zone)                             \
 807        for (zone = (first_online_pgdat())->node_zones; \
 808             zone;                                      \
 809             zone = next_zone(zone))
 810
 811#define for_each_populated_zone(zone)                   \
 812        for (zone = (first_online_pgdat())->node_zones; \
 813             zone;                                      \
 814             zone = next_zone(zone))                    \
 815                if (!populated_zone(zone))              \
 816                        ; /* do nothing */              \
 817                else
 818
 819static inline struct zone *zonelist_zone(struct zoneref *zoneref)
 820{
 821        return zoneref->zone;
 822}
 823
 824static inline int zonelist_zone_idx(struct zoneref *zoneref)
 825{
 826        return zoneref->zone_idx;
 827}
 828
 829static inline int zonelist_node_idx(struct zoneref *zoneref)
 830{
 831#ifdef CONFIG_NUMA
 832        /* zone_to_nid not available in this context */
 833        return zoneref->zone->node;
 834#else
 835        return 0;
 836#endif /* CONFIG_NUMA */
 837}
 838
 839/**
 840 * next_zones_zonelist - Returns the next zone at or below highest_zoneidx within the allowed nodemask using a cursor within a zonelist as a starting point
 841 * @z - The cursor used as a starting point for the search
 842 * @highest_zoneidx - The zone index of the highest zone to return
 843 * @nodes - An optional nodemask to filter the zonelist with
 844 * @zone - The first suitable zone found is returned via this parameter
 845 *
 846 * This function returns the next zone at or below a given zone index that is
 847 * within the allowed nodemask using a cursor as the starting point for the
 848 * search. The zoneref returned is a cursor that represents the current zone
 849 * being examined. It should be advanced by one before calling
 850 * next_zones_zonelist again.
 851 */
 852struct zoneref *next_zones_zonelist(struct zoneref *z,
 853                                        enum zone_type highest_zoneidx,
 854                                        nodemask_t *nodes,
 855                                        struct zone **zone);
 856
 857/**
 858 * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
 859 * @zonelist - The zonelist to search for a suitable zone
 860 * @highest_zoneidx - The zone index of the highest zone to return
 861 * @nodes - An optional nodemask to filter the zonelist with
 862 * @zone - The first suitable zone found is returned via this parameter
 863 *
 864 * This function returns the first zone at or below a given zone index that is
 865 * within the allowed nodemask. The zoneref returned is a cursor that can be
 866 * used to iterate the zonelist with next_zones_zonelist by advancing it by
 867 * one before calling.
 868 */
 869static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
 870                                        enum zone_type highest_zoneidx,
 871                                        nodemask_t *nodes,
 872                                        struct zone **zone)
 873{
 874        return next_zones_zonelist(zonelist->_zonerefs, highest_zoneidx, nodes,
 875                                                                zone);
 876}
 877
 878/**
 879 * for_each_zone_zonelist_nodemask - helper macro to iterate over valid zones in a zonelist at or below a given zone index and within a nodemask
 880 * @zone - The current zone in the iterator
 881 * @z - The current pointer within zonelist->zones being iterated
 882 * @zlist - The zonelist being iterated
 883 * @highidx - The zone index of the highest zone to return
 884 * @nodemask - Nodemask allowed by the allocator
 885 *
 886 * This iterator iterates though all zones at or below a given zone index and
 887 * within a given nodemask
 888 */
 889#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
 890        for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone); \
 891                zone;                                                   \
 892                z = next_zones_zonelist(++z, highidx, nodemask, &zone)) \
 893
 894/**
 895 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
 896 * @zone - The current zone in the iterator
 897 * @z - The current pointer within zonelist->zones being iterated
 898 * @zlist - The zonelist being iterated
 899 * @highidx - The zone index of the highest zone to return
 900 *
 901 * This iterator iterates though all zones at or below a given zone index.
 902 */
 903#define for_each_zone_zonelist(zone, z, zlist, highidx) \
 904        for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
 905
 906#ifdef CONFIG_SPARSEMEM
 907#include <asm/sparsemem.h>
 908#endif
 909
 910#if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
 911        !defined(CONFIG_ARCH_POPULATES_NODE_MAP)
 912static inline unsigned long early_pfn_to_nid(unsigned long pfn)
 913{
 914        return 0;
 915}
 916#endif
 917
 918#ifdef CONFIG_FLATMEM
 919#define pfn_to_nid(pfn)         (0)
 920#endif
 921
 922#define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
 923#define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
 924
 925#ifdef CONFIG_SPARSEMEM
 926
 927/*
 928 * SECTION_SHIFT                #bits space required to store a section #
 929 *
 930 * PA_SECTION_SHIFT             physical address to/from section number
 931 * PFN_SECTION_SHIFT            pfn to/from section number
 932 */
 933#define SECTIONS_SHIFT          (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
 934
 935#define PA_SECTION_SHIFT        (SECTION_SIZE_BITS)
 936#define PFN_SECTION_SHIFT       (SECTION_SIZE_BITS - PAGE_SHIFT)
 937
 938#define NR_MEM_SECTIONS         (1UL << SECTIONS_SHIFT)
 939
 940#define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
 941#define PAGE_SECTION_MASK       (~(PAGES_PER_SECTION-1))
 942
 943#define SECTION_BLOCKFLAGS_BITS \
 944        ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
 945
 946#if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
 947#error Allocator MAX_ORDER exceeds SECTION_SIZE
 948#endif
 949
 950struct page;
 951struct page_cgroup;
 952struct mem_section {
 953        /*
 954         * This is, logically, a pointer to an array of struct
 955         * pages.  However, it is stored with some other magic.
 956         * (see sparse.c::sparse_init_one_section())
 957         *
 958         * Additionally during early boot we encode node id of
 959         * the location of the section here to guide allocation.
 960         * (see sparse.c::memory_present())
 961         *
 962         * Making it a UL at least makes someone do a cast
 963         * before using it wrong.
 964         */
 965        unsigned long section_mem_map;
 966
 967        /* See declaration of similar field in struct zone */
 968        unsigned long *pageblock_flags;
 969#ifdef CONFIG_CGROUP_MEM_RES_CTLR
 970        /*
 971         * If !SPARSEMEM, pgdat doesn't have page_cgroup pointer. We use
 972         * section. (see memcontrol.h/page_cgroup.h about this.)
 973         */
 974        struct page_cgroup *page_cgroup;
 975        unsigned long pad;
 976#endif
 977};
 978
 979#ifdef CONFIG_SPARSEMEM_EXTREME
 980#define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
 981#else
 982#define SECTIONS_PER_ROOT       1
 983#endif
 984
 985#define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
 986#define NR_SECTION_ROOTS        (NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
 987#define SECTION_ROOT_MASK       (SECTIONS_PER_ROOT - 1)
 988
 989#ifdef CONFIG_SPARSEMEM_EXTREME
 990extern struct mem_section *mem_section[NR_SECTION_ROOTS];
 991#else
 992extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
 993#endif
 994
 995static inline struct mem_section *__nr_to_section(unsigned long nr)
 996{
 997        if (!mem_section[SECTION_NR_TO_ROOT(nr)])
 998                return NULL;
 999        return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
1000}
1001extern int __section_nr(struct mem_section* ms);
1002extern unsigned long usemap_size(void);
1003
1004/*
1005 * We use the lower bits of the mem_map pointer to store
1006 * a little bit of information.  There should be at least
1007 * 3 bits here due to 32-bit alignment.
1008 */
1009#define SECTION_MARKED_PRESENT  (1UL<<0)
1010#define SECTION_HAS_MEM_MAP     (1UL<<1)
1011#define SECTION_MAP_LAST_BIT    (1UL<<2)
1012#define SECTION_MAP_MASK        (~(SECTION_MAP_LAST_BIT-1))
1013#define SECTION_NID_SHIFT       2
1014
1015static inline struct page *__section_mem_map_addr(struct mem_section *section)
1016{
1017        unsigned long map = section->section_mem_map;
1018        map &= SECTION_MAP_MASK;
1019        return (struct page *)map;
1020}
1021
1022static inline int present_section(struct mem_section *section)
1023{
1024        return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1025}
1026
1027static inline int present_section_nr(unsigned long nr)
1028{
1029        return present_section(__nr_to_section(nr));
1030}
1031
1032static inline int valid_section(struct mem_section *section)
1033{
1034        return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1035}
1036
1037static inline int valid_section_nr(unsigned long nr)
1038{
1039        return valid_section(__nr_to_section(nr));
1040}
1041
1042static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1043{
1044        return __nr_to_section(pfn_to_section_nr(pfn));
1045}
1046
1047static inline int pfn_valid(unsigned long pfn)
1048{
1049        if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1050                return 0;
1051        return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
1052}
1053
1054static inline int pfn_present(unsigned long pfn)
1055{
1056        if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1057                return 0;
1058        return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
1059}
1060
1061/*
1062 * These are _only_ used during initialisation, therefore they
1063 * can use __initdata ...  They could have names to indicate
1064 * this restriction.
1065 */
1066#ifdef CONFIG_NUMA
1067#define pfn_to_nid(pfn)                                                 \
1068({                                                                      \
1069        unsigned long __pfn_to_nid_pfn = (pfn);                         \
1070        page_to_nid(pfn_to_page(__pfn_to_nid_pfn));                     \
1071})
1072#else
1073#define pfn_to_nid(pfn)         (0)
1074#endif
1075
1076#define early_pfn_valid(pfn)    pfn_valid(pfn)
1077void sparse_init(void);
1078#else
1079#define sparse_init()   do {} while (0)
1080#define sparse_index_init(_sec, _nid)  do {} while (0)
1081#endif /* CONFIG_SPARSEMEM */
1082
1083#ifdef CONFIG_NODES_SPAN_OTHER_NODES
1084bool early_pfn_in_nid(unsigned long pfn, int nid);
1085#else
1086#define early_pfn_in_nid(pfn, nid)      (1)
1087#endif
1088
1089#ifndef early_pfn_valid
1090#define early_pfn_valid(pfn)    (1)
1091#endif
1092
1093void memory_present(int nid, unsigned long start, unsigned long end);
1094unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
1095
1096/*
1097 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
1098 * need to check pfn validility within that MAX_ORDER_NR_PAGES block.
1099 * pfn_valid_within() should be used in this case; we optimise this away
1100 * when we have no holes within a MAX_ORDER_NR_PAGES block.
1101 */
1102#ifdef CONFIG_HOLES_IN_ZONE
1103#define pfn_valid_within(pfn) pfn_valid(pfn)
1104#else
1105#define pfn_valid_within(pfn) (1)
1106#endif
1107
1108#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
1109/*
1110 * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
1111 * associated with it or not. In FLATMEM, it is expected that holes always
1112 * have valid memmap as long as there is valid PFNs either side of the hole.
1113 * In SPARSEMEM, it is assumed that a valid section has a memmap for the
1114 * entire section.
1115 *
1116 * However, an ARM, and maybe other embedded architectures in the future
1117 * free memmap backing holes to save memory on the assumption the memmap is
1118 * never used. The page_zone linkages are then broken even though pfn_valid()
1119 * returns true. A walker of the full memmap must then do this additional
1120 * check to ensure the memmap they are looking at is sane by making sure
1121 * the zone and PFN linkages are still valid. This is expensive, but walkers
1122 * of the full memmap are extremely rare.
1123 */
1124int memmap_valid_within(unsigned long pfn,
1125                                        struct page *page, struct zone *zone);
1126#else
1127static inline int memmap_valid_within(unsigned long pfn,
1128                                        struct page *page, struct zone *zone)
1129{
1130        return 1;
1131}
1132#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
1133
1134#endif /* !__GENERATING_BOUNDS.H */
1135#endif /* !__ASSEMBLY__ */
1136#endif /* _LINUX_MMZONE_H */
1137