LCOV - code coverage report
Current view: top level - include/linux - mmzone.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 10 10 100.0 %
Date: 2017-01-25 Functions: 3 3 100.0 %

          Line data    Source code
       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 <generated/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             : 
      50             : extern int page_group_by_mobility_disabled;
      51             : 
      52             : static inline int get_pageblock_migratetype(struct page *page)
      53             : {
      54             :         return get_pageblock_flags_group(page, PB_migrate, PB_migrate_end);
      55             : }
      56             : 
      57             : struct free_area {
      58             :         struct list_head        free_list[MIGRATE_TYPES];
      59             :         unsigned long           nr_free;
      60             : };
      61             : 
      62             : struct 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)
      71             : struct 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             : 
      79             : enum 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             : 
     130             : enum 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             : 
     143             : static inline int is_file_lru(enum lru_list l)
     144             : {
     145             :         return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
     146             : }
     147             : 
     148             : static inline int is_active_lru(enum lru_list l)
     149             : {
     150             :         return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
     151             : }
     152             : 
     153             : static inline int is_unevictable_lru(enum lru_list l)
     154             : {
     155             :         return (l == LRU_UNEVICTABLE);
     156             : }
     157             : 
     158             : enum 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             : 
     169             : struct 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             : 
     178             : struct 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             : 
     197             : enum 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             : 
     268             : struct 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             : 
     286             : struct 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             :          * When free pages are below this point, additional steps are taken
     294             :          * when reading the number of free pages to avoid per-cpu counter
     295             :          * drift allowing watermarks to be breached
     296             :          */
     297             :         unsigned long percpu_drift_mark;
     298             : 
     299             :         /*
     300             :          * We don't know if the memory that we're going to allocate will be freeable
     301             :          * or/and it will be released eventually, so to avoid totally wasting several
     302             :          * GB of ram we must reserve some of the lower zone memory (otherwise we risk
     303             :          * to run OOM on the lower zones despite there's tons of freeable ram
     304             :          * on the higher zones). This array is recalculated at runtime if the
     305             :          * sysctl_lowmem_reserve_ratio sysctl changes.
     306             :          */
     307             :         unsigned long           lowmem_reserve[MAX_NR_ZONES];
     308             : 
     309             : #ifdef CONFIG_NUMA
     310             :         int node;
     311             :         /*
     312             :          * zone reclaim becomes active if more unmapped pages exist.
     313             :          */
     314             :         unsigned long           min_unmapped_pages;
     315             :         unsigned long           min_slab_pages;
     316             :         struct per_cpu_pageset  *pageset[NR_CPUS];
     317             : #else
     318             :         struct per_cpu_pageset  pageset[NR_CPUS];
     319             : #endif
     320             :         /*
     321             :          * free areas of different sizes
     322             :          */
     323             :         spinlock_t              lock;
     324             : #ifdef CONFIG_MEMORY_HOTPLUG
     325             :         /* see spanned/present_pages for more description */
     326             :         seqlock_t               span_seqlock;
     327             : #endif
     328             :         struct free_area        free_area[MAX_ORDER];
     329             : 
     330             : #ifndef CONFIG_SPARSEMEM
     331             :         /*
     332             :          * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
     333             :          * In SPARSEMEM, this map is stored in struct mem_section
     334             :          */
     335             :         unsigned long           *pageblock_flags;
     336             : #endif /* CONFIG_SPARSEMEM */
     337             : 
     338             : 
     339             :         ZONE_PADDING(_pad1_)
     340             : 
     341             :         /* Fields commonly accessed by the page reclaim scanner */
     342             :         spinlock_t              lru_lock;       
     343             :         struct zone_lru {
     344             :                 struct list_head list;
     345             :         } lru[NR_LRU_LISTS];
     346             : 
     347             :         struct zone_reclaim_stat reclaim_stat;
     348             : 
     349             :         unsigned long           pages_scanned;     /* since last reclaim */
     350             :         unsigned long           flags;             /* zone flags, see below */
     351             : 
     352             :         /* Zone statistics */
     353             :         atomic_long_t           vm_stat[NR_VM_ZONE_STAT_ITEMS];
     354             : 
     355             :         /*
     356             :          * prev_priority holds the scanning priority for this zone.  It is
     357             :          * defined as the scanning priority at which we achieved our reclaim
     358             :          * target at the previous try_to_free_pages() or balance_pgdat()
     359             :          * invokation.
     360             :          *
     361             :          * We use prev_priority as a measure of how much stress page reclaim is
     362             :          * under - it drives the swappiness decision: whether to unmap mapped
     363             :          * pages.
     364             :          *
     365             :          * Access to both this field is quite racy even on uniprocessor.  But
     366             :          * it is expected to average out OK.
     367             :          */
     368             :         int prev_priority;
     369             : 
     370             :         /*
     371             :          * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
     372             :          * this zone's LRU.  Maintained by the pageout code.
     373             :          */
     374             :         unsigned int inactive_ratio;
     375             : 
     376             : 
     377             :         ZONE_PADDING(_pad2_)
     378             :         /* Rarely used or read-mostly fields */
     379             : 
     380             :         /*
     381             :          * wait_table           -- the array holding the hash table
     382             :          * wait_table_hash_nr_entries   -- the size of the hash table array
     383             :          * wait_table_bits      -- wait_table_size == (1 << wait_table_bits)
     384             :          *
     385             :          * The purpose of all these is to keep track of the people
     386             :          * waiting for a page to become available and make them
     387             :          * runnable again when possible. The trouble is that this
     388             :          * consumes a lot of space, especially when so few things
     389             :          * wait on pages at a given time. So instead of using
     390             :          * per-page waitqueues, we use a waitqueue hash table.
     391             :          *
     392             :          * The bucket discipline is to sleep on the same queue when
     393             :          * colliding and wake all in that wait queue when removing.
     394             :          * When something wakes, it must check to be sure its page is
     395             :          * truly available, a la thundering herd. The cost of a
     396             :          * collision is great, but given the expected load of the
     397             :          * table, they should be so rare as to be outweighed by the
     398             :          * benefits from the saved space.
     399             :          *
     400             :          * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
     401             :          * primary users of these fields, and in mm/page_alloc.c
     402             :          * free_area_init_core() performs the initialization of them.
     403             :          */
     404             :         wait_queue_head_t       * wait_table;
     405             :         unsigned long           wait_table_hash_nr_entries;
     406             :         unsigned long           wait_table_bits;
     407             : 
     408             :         /*
     409             :          * Discontig memory support fields.
     410             :          */
     411             :         struct pglist_data      *zone_pgdat;
     412             :         /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
     413             :         unsigned long           zone_start_pfn;
     414             : 
     415             :         /*
     416             :          * zone_start_pfn, spanned_pages and present_pages are all
     417             :          * protected by span_seqlock.  It is a seqlock because it has
     418             :          * to be read outside of zone->lock, and it is done in the main
     419             :          * allocator path.  But, it is written quite infrequently.
     420             :          *
     421             :          * The lock is declared along with zone->lock because it is
     422             :          * frequently read in proximity to zone->lock.  It's good to
     423             :          * give them a chance of being in the same cacheline.
     424             :          */
     425             :         unsigned long           spanned_pages;  /* total size, including holes */
     426             :         unsigned long           present_pages;  /* amount of memory (excluding holes) */
     427             : 
     428             :         /*
     429             :          * rarely used fields:
     430             :          */
     431             :         const char              *name;
     432             : } ____cacheline_internodealigned_in_smp;
     433             : 
     434             : typedef enum {
     435             :         ZONE_ALL_UNRECLAIMABLE,         /* all pages pinned */
     436             :         ZONE_RECLAIM_LOCKED,            /* prevents concurrent reclaim */
     437             :         ZONE_OOM_LOCKED,                /* zone is in OOM killer zonelist */
     438             : } zone_flags_t;
     439             : 
     440             : static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
     441             : {
     442             :         set_bit(flag, &zone->flags);
     443             : }
     444             : 
     445             : static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
     446             : {
     447             :         return test_and_set_bit(flag, &zone->flags);
     448             : }
     449             : 
     450             : static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
     451             : {
     452             :         clear_bit(flag, &zone->flags);
     453             : }
     454             : 
     455             : static inline int zone_is_all_unreclaimable(const struct zone *zone)
     456             : {
     457             :         return test_bit(ZONE_ALL_UNRECLAIMABLE, &zone->flags);
     458             : }
     459             : 
     460             : static inline int zone_is_reclaim_locked(const struct zone *zone)
     461             : {
     462             :         return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
     463             : }
     464             : 
     465             : static inline int zone_is_oom_locked(const struct zone *zone)
     466             : {
     467             :         return test_bit(ZONE_OOM_LOCKED, &zone->flags);
     468             : }
     469             : 
     470             : #ifdef CONFIG_SMP
     471             : unsigned long zone_nr_free_pages(struct zone *zone);
     472             : #else
     473             : #define zone_nr_free_pages(zone) zone_page_state(zone, NR_FREE_PAGES)
     474             : #endif /* CONFIG_SMP */
     475             : 
     476             : /*
     477             :  * The "priority" of VM scanning is how much of the queues we will scan in one
     478             :  * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
     479             :  * queues ("queue_length >> 12") during an aging round.
     480             :  */
     481             : #define DEF_PRIORITY 12
     482             : 
     483             : /* Maximum number of zones on a zonelist */
     484             : #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
     485             : 
     486             : #ifdef CONFIG_NUMA
     487             : 
     488             : /*
     489             :  * The NUMA zonelists are doubled becausse we need zonelists that restrict the
     490             :  * allocations to a single node for GFP_THISNODE.
     491             :  *
     492             :  * [0]  : Zonelist with fallback
     493             :  * [1]  : No fallback (GFP_THISNODE)
     494             :  */
     495             : #define MAX_ZONELISTS 2
     496             : 
     497             : 
     498             : /*
     499             :  * We cache key information from each zonelist for smaller cache
     500             :  * footprint when scanning for free pages in get_page_from_freelist().
     501             :  *
     502             :  * 1) The BITMAP fullzones tracks which zones in a zonelist have come
     503             :  *    up short of free memory since the last time (last_fullzone_zap)
     504             :  *    we zero'd fullzones.
     505             :  * 2) The array z_to_n[] maps each zone in the zonelist to its node
     506             :  *    id, so that we can efficiently evaluate whether that node is
     507             :  *    set in the current tasks mems_allowed.
     508             :  *
     509             :  * Both fullzones and z_to_n[] are one-to-one with the zonelist,
     510             :  * indexed by a zones offset in the zonelist zones[] array.
     511             :  *
     512             :  * The get_page_from_freelist() routine does two scans.  During the
     513             :  * first scan, we skip zones whose corresponding bit in 'fullzones'
     514             :  * is set or whose corresponding node in current->mems_allowed (which
     515             :  * comes from cpusets) is not set.  During the second scan, we bypass
     516             :  * this zonelist_cache, to ensure we look methodically at each zone.
     517             :  *
     518             :  * Once per second, we zero out (zap) fullzones, forcing us to
     519             :  * reconsider nodes that might have regained more free memory.
     520             :  * The field last_full_zap is the time we last zapped fullzones.
     521             :  *
     522             :  * This mechanism reduces the amount of time we waste repeatedly
     523             :  * reexaming zones for free memory when they just came up low on
     524             :  * memory momentarilly ago.
     525             :  *
     526             :  * The zonelist_cache struct members logically belong in struct
     527             :  * zonelist.  However, the mempolicy zonelists constructed for
     528             :  * MPOL_BIND are intentionally variable length (and usually much
     529             :  * shorter).  A general purpose mechanism for handling structs with
     530             :  * multiple variable length members is more mechanism than we want
     531             :  * here.  We resort to some special case hackery instead.
     532             :  *
     533             :  * The MPOL_BIND zonelists don't need this zonelist_cache (in good
     534             :  * part because they are shorter), so we put the fixed length stuff
     535             :  * at the front of the zonelist struct, ending in a variable length
     536             :  * zones[], as is needed by MPOL_BIND.
     537             :  *
     538             :  * Then we put the optional zonelist cache on the end of the zonelist
     539             :  * struct.  This optional stuff is found by a 'zlcache_ptr' pointer in
     540             :  * the fixed length portion at the front of the struct.  This pointer
     541             :  * both enables us to find the zonelist cache, and in the case of
     542             :  * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL)
     543             :  * to know that the zonelist cache is not there.
     544             :  *
     545             :  * The end result is that struct zonelists come in two flavors:
     546             :  *  1) The full, fixed length version, shown below, and
     547             :  *  2) The custom zonelists for MPOL_BIND.
     548             :  * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache.
     549             :  *
     550             :  * Even though there may be multiple CPU cores on a node modifying
     551             :  * fullzones or last_full_zap in the same zonelist_cache at the same
     552             :  * time, we don't lock it.  This is just hint data - if it is wrong now
     553             :  * and then, the allocator will still function, perhaps a bit slower.
     554             :  */
     555             : 
     556             : 
     557             : struct zonelist_cache {
     558             :         unsigned short z_to_n[MAX_ZONES_PER_ZONELIST];          /* zone->nid */
     559             :         DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST);      /* zone full? */
     560             :         unsigned long last_full_zap;            /* when last zap'd (jiffies) */
     561             : };
     562             : #else
     563             : #define MAX_ZONELISTS 1
     564             : struct zonelist_cache;
     565             : #endif
     566             : 
     567             : /*
     568             :  * This struct contains information about a zone in a zonelist. It is stored
     569             :  * here to avoid dereferences into large structures and lookups of tables
     570             :  */
     571             : struct zoneref {
     572             :         struct zone *zone;      /* Pointer to actual zone */
     573             :         int zone_idx;           /* zone_idx(zoneref->zone) */
     574             : };
     575             : 
     576             : /*
     577             :  * One allocation request operates on a zonelist. A zonelist
     578             :  * is a list of zones, the first one is the 'goal' of the
     579             :  * allocation, the other zones are fallback zones, in decreasing
     580             :  * priority.
     581             :  *
     582             :  * If zlcache_ptr is not NULL, then it is just the address of zlcache,
     583             :  * as explained above.  If zlcache_ptr is NULL, there is no zlcache.
     584             :  * *
     585             :  * To speed the reading of the zonelist, the zonerefs contain the zone index
     586             :  * of the entry being read. Helper functions to access information given
     587             :  * a struct zoneref are
     588             :  *
     589             :  * zonelist_zone()      - Return the struct zone * for an entry in _zonerefs
     590             :  * zonelist_zone_idx()  - Return the index of the zone for an entry
     591             :  * zonelist_node_idx()  - Return the index of the node for an entry
     592             :  */
     593             : struct zonelist {
     594             :         struct zonelist_cache *zlcache_ptr;                  // NULL or &zlcache
     595             :         struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
     596             : #ifdef CONFIG_NUMA
     597             :         struct zonelist_cache zlcache;                       // optional ...
     598             : #endif
     599             : };
     600             : 
     601             : #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
     602             : struct node_active_region {
     603             :         unsigned long start_pfn;
     604             :         unsigned long end_pfn;
     605             :         int nid;
     606             : };
     607             : #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
     608             : 
     609             : #ifndef CONFIG_DISCONTIGMEM
     610             : /* The array of struct pages - for discontigmem use pgdat->lmem_map */
     611             : extern struct page *mem_map;
     612             : #endif
     613             : 
     614             : /*
     615             :  * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
     616             :  * (mostly NUMA machines?) to denote a higher-level memory zone than the
     617             :  * zone denotes.
     618             :  *
     619             :  * On NUMA machines, each NUMA node would have a pg_data_t to describe
     620             :  * it's memory layout.
     621             :  *
     622             :  * Memory statistics and page replacement data structures are maintained on a
     623             :  * per-zone basis.
     624             :  */
     625             : struct bootmem_data;
     626             : typedef struct pglist_data {
     627             :         struct zone node_zones[MAX_NR_ZONES];
     628             :         struct zonelist node_zonelists[MAX_ZONELISTS];
     629             :         int nr_zones;
     630             : #ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
     631             :         struct page *node_mem_map;
     632             : #ifdef CONFIG_CGROUP_MEM_RES_CTLR
     633             :         struct page_cgroup *node_page_cgroup;
     634             : #endif
     635             : #endif
     636             :         struct bootmem_data *bdata;
     637             : #ifdef CONFIG_MEMORY_HOTPLUG
     638             :         /*
     639             :          * Must be held any time you expect node_start_pfn, node_present_pages
     640             :          * or node_spanned_pages stay constant.  Holding this will also
     641             :          * guarantee that any pfn_valid() stays that way.
     642             :          *
     643             :          * Nests above zone->lock and zone->size_seqlock.
     644             :          */
     645             :         spinlock_t node_size_lock;
     646             : #endif
     647             :         unsigned long node_start_pfn;
     648             :         unsigned long node_present_pages; /* total number of physical pages */
     649             :         unsigned long node_spanned_pages; /* total size of physical page
     650             :                                              range, including holes */
     651             :         int node_id;
     652             :         wait_queue_head_t kswapd_wait;
     653             :         struct task_struct *kswapd;
     654             :         int kswapd_max_order;
     655             : } pg_data_t;
     656           1 : 
     657             : #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
     658             : #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
     659             : #ifdef CONFIG_FLAT_NODE_MEM_MAP
     660             : #define pgdat_page_nr(pgdat, pagenr)    ((pgdat)->node_mem_map + (pagenr))
     661             : #else
     662             : #define pgdat_page_nr(pgdat, pagenr)    pfn_to_page((pgdat)->node_start_pfn + (pagenr))
     663             : #endif
     664             : #define nid_page_nr(nid, pagenr)        pgdat_page_nr(NODE_DATA(nid),(pagenr))
     665             : 
     666             : #include <linux/memory_hotplug.h>
     667             : 
     668             : void get_zone_counts(unsigned long *active, unsigned long *inactive,
     669             :                         unsigned long *free);
     670             : void build_all_zonelists(void);
     671             : void wakeup_kswapd(struct zone *zone, int order);
     672             : int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
     673             :                 int classzone_idx, int alloc_flags);
     674             : enum memmap_context {
     675             :         MEMMAP_EARLY,
     676             :         MEMMAP_HOTPLUG,
     677             : };
     678             : extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
     679             :                                      unsigned long size,
     680             :                                      enum memmap_context context);
     681             : 
     682             : #ifdef CONFIG_HAVE_MEMORY_PRESENT
     683             : void memory_present(int nid, unsigned long start, unsigned long end);
     684             : #else
     685             : static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
     686             : #endif
     687             : 
     688             : #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
     689             : unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
     690             : #endif
     691             : 
     692             : /*
     693             :  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
     694             :  */
     695             : #define zone_idx(zone)          ((zone) - (zone)->zone_pgdat->node_zones)
     696             : 
     697             : static inline int populated_zone(struct zone *zone)
     698             : {
     699             :         return (!!zone->present_pages);
     700             : }
     701             : 
     702             : extern int movable_zone;
     703             : 
     704             : static inline int zone_movable_is_highmem(void)
     705             : {
     706             : #if defined(CONFIG_HIGHMEM) && defined(CONFIG_ARCH_POPULATES_NODE_MAP)
     707             :         return movable_zone == ZONE_HIGHMEM;
     708             : #else
     709             :         return 0;
     710             : #endif
     711             : }
     712             : 
     713             : static inline int is_highmem_idx(enum zone_type idx)
     714             : {
     715             : #ifdef CONFIG_HIGHMEM
     716             :         return (idx == ZONE_HIGHMEM ||
     717             :                 (idx == ZONE_MOVABLE && zone_movable_is_highmem()));
     718             : #else
     719             :         return 0;
     720             : #endif
     721             : }
     722             : 
     723             : static inline int is_normal_idx(enum zone_type idx)
     724             : {
     725             :         return (idx == ZONE_NORMAL);
     726             : }
     727             : 
     728             : /**
     729             :  * is_highmem - helper function to quickly check if a struct zone is a 
     730             :  *              highmem zone or not.  This is an attempt to keep references
     731             :  *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
     732             :  * @zone - pointer to struct zone variable
     733             :  */
     734             : static inline int is_highmem(struct zone *zone)
     735             : {
     736             : #ifdef CONFIG_HIGHMEM
     737             :         int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
     738             :         return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
     739             :                (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
     740             :                 zone_movable_is_highmem());
     741             : #else
     742             :         return 0;
     743             : #endif
     744             : }
     745             : 
     746             : static inline int is_normal(struct zone *zone)
     747             : {
     748             :         return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
     749             : }
     750             : 
     751             : static inline int is_dma32(struct zone *zone)
     752             : {
     753             : #ifdef CONFIG_ZONE_DMA32
     754             :         return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
     755             : #else
     756             :         return 0;
     757             : #endif
     758             : }
     759             : 
     760             : static inline int is_dma(struct zone *zone)
     761             : {
     762             : #ifdef CONFIG_ZONE_DMA
     763             :         return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
     764             : #else
     765             :         return 0;
     766             : #endif
     767             : }
     768             : 
     769             : /* These two functions are used to setup the per zone pages min values */
     770             : struct ctl_table;
     771             : int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
     772             :                                         void __user *, size_t *, loff_t *);
     773             : extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
     774             : int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
     775             :                                         void __user *, size_t *, loff_t *);
     776             : int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
     777             :                                         void __user *, size_t *, loff_t *);
     778             : int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
     779             :                         void __user *, size_t *, loff_t *);
     780             : int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
     781             :                         void __user *, size_t *, loff_t *);
     782             : 
     783             : extern int numa_zonelist_order_handler(struct ctl_table *, int,
     784             :                         void __user *, size_t *, loff_t *);
     785             : extern char numa_zonelist_order[];
     786             : #define NUMA_ZONELIST_ORDER_LEN 16      /* string buffer size */
     787             : 
     788             : #ifndef CONFIG_NEED_MULTIPLE_NODES
     789             : 
     790             : extern struct pglist_data contig_page_data;
     791             : #define NODE_DATA(nid)          (&contig_page_data)
     792             : #define NODE_MEM_MAP(nid)       mem_map
     793             : 
     794             : #else /* CONFIG_NEED_MULTIPLE_NODES */
     795             : 
     796             : #include <asm/mmzone.h>
     797             : 
     798             : #endif /* !CONFIG_NEED_MULTIPLE_NODES */
     799             : 
     800             : extern struct pglist_data *first_online_pgdat(void);
     801             : extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
     802             : extern struct zone *next_zone(struct zone *zone);
     803             : 
     804             : /**
     805             :  * for_each_online_pgdat - helper macro to iterate over all online nodes
     806             :  * @pgdat - pointer to a pg_data_t variable
     807             :  */
     808             : #define for_each_online_pgdat(pgdat)                    \
     809             :         for (pgdat = first_online_pgdat();              \
     810             :              pgdat;                                     \
     811             :              pgdat = next_online_pgdat(pgdat))
     812             : /**
     813             :  * for_each_zone - helper macro to iterate over all memory zones
     814             :  * @zone - pointer to struct zone variable
     815             :  *
     816             :  * The user only needs to declare the zone variable, for_each_zone
     817             :  * fills it in.
     818             :  */
     819             : #define for_each_zone(zone)                             \
     820             :         for (zone = (first_online_pgdat())->node_zones; \
     821             :              zone;                                      \
     822             :              zone = next_zone(zone))
     823             : 
     824             : #define for_each_populated_zone(zone)                   \
     825             :         for (zone = (first_online_pgdat())->node_zones; \
     826             :              zone;                                      \
     827             :              zone = next_zone(zone))                    \
     828             :                 if (!populated_zone(zone))              \
     829             :                         ; /* do nothing */              \
     830             :                 else
     831             : 
     832             : static inline struct zone *zonelist_zone(struct zoneref *zoneref)
     833             : {
     834             :         return zoneref->zone;
     835             : }
     836             : 
     837             : static inline int zonelist_zone_idx(struct zoneref *zoneref)
     838             : {
     839             :         return zoneref->zone_idx;
     840             : }
     841             : 
     842             : static inline int zonelist_node_idx(struct zoneref *zoneref)
     843             : {
     844             : #ifdef CONFIG_NUMA
     845             :         /* zone_to_nid not available in this context */
     846             :         return zoneref->zone->node;
     847             : #else
     848             :         return 0;
     849             : #endif /* CONFIG_NUMA */
     850             : }
     851             : 
     852             : /**
     853             :  * 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
     854             :  * @z - The cursor used as a starting point for the search
     855             :  * @highest_zoneidx - The zone index of the highest zone to return
     856             :  * @nodes - An optional nodemask to filter the zonelist with
     857             :  * @zone - The first suitable zone found is returned via this parameter
     858             :  *
     859             :  * This function returns the next zone at or below a given zone index that is
     860             :  * within the allowed nodemask using a cursor as the starting point for the
     861             :  * search. The zoneref returned is a cursor that represents the current zone
     862             :  * being examined. It should be advanced by one before calling
     863             :  * next_zones_zonelist again.
     864             :  */
     865             : struct zoneref *next_zones_zonelist(struct zoneref *z,
     866             :                                         enum zone_type highest_zoneidx,
     867             :                                         nodemask_t *nodes,
     868             :                                         struct zone **zone);
     869             : 
     870             : /**
     871             :  * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
     872             :  * @zonelist - The zonelist to search for a suitable zone
     873             :  * @highest_zoneidx - The zone index of the highest zone to return
     874             :  * @nodes - An optional nodemask to filter the zonelist with
     875             :  * @zone - The first suitable zone found is returned via this parameter
     876             :  *
     877             :  * This function returns the first zone at or below a given zone index that is
     878             :  * within the allowed nodemask. The zoneref returned is a cursor that can be
     879             :  * used to iterate the zonelist with next_zones_zonelist by advancing it by
     880             :  * one before calling.
     881             :  */
     882             : static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
     883             :                                         enum zone_type highest_zoneidx,
     884             :                                         nodemask_t *nodes,
     885             :                                         struct zone **zone)
     886             : {
     887             :         return next_zones_zonelist(zonelist->_zonerefs, highest_zoneidx, nodes,
     888             :                                                                 zone);
     889             : }
     890           1 : 
     891             : /**
     892             :  * 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
     893             :  * @zone - The current zone in the iterator
     894             :  * @z - The current pointer within zonelist->zones being iterated
     895             :  * @zlist - The zonelist being iterated
     896             :  * @highidx - The zone index of the highest zone to return
     897             :  * @nodemask - Nodemask allowed by the allocator
     898             :  *
     899             :  * This iterator iterates though all zones at or below a given zone index and
     900             :  * within a given nodemask
     901             :  */
     902             : #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
     903             :         for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone);     \
     904             :                 zone;                                                   \
     905             :                 z = next_zones_zonelist(++z, highidx, nodemask, &zone))     \
     906             : 
     907             : /**
     908             :  * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
     909             :  * @zone - The current zone in the iterator
     910             :  * @z - The current pointer within zonelist->zones being iterated
     911             :  * @zlist - The zonelist being iterated
     912             :  * @highidx - The zone index of the highest zone to return
     913             :  *
     914             :  * This iterator iterates though all zones at or below a given zone index.
     915             :  */
     916             : #define for_each_zone_zonelist(zone, z, zlist, highidx) \
     917             :         for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
     918             : 
     919             : #ifdef CONFIG_SPARSEMEM
     920             : #include <asm/sparsemem.h>
     921             : #endif
     922             : 
     923             : #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
     924             :         !defined(CONFIG_ARCH_POPULATES_NODE_MAP)
     925             : static inline unsigned long early_pfn_to_nid(unsigned long pfn)
     926             : {
     927             :         return 0;
     928             : }
     929             : #endif
     930             : 
     931             : #ifdef CONFIG_FLATMEM
     932             : #define pfn_to_nid(pfn)         (0)
     933             : #endif
     934             : 
     935             : #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
     936             : #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
     937             : 
     938             : #ifdef CONFIG_SPARSEMEM
     939             : 
     940             : /*
     941             :  * SECTION_SHIFT                #bits space required to store a section #
     942             :  *
     943             :  * PA_SECTION_SHIFT             physical address to/from section number
     944             :  * PFN_SECTION_SHIFT            pfn to/from section number
     945             :  */
     946             : #define SECTIONS_SHIFT          (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
     947             : 
     948             : #define PA_SECTION_SHIFT        (SECTION_SIZE_BITS)
     949             : #define PFN_SECTION_SHIFT       (SECTION_SIZE_BITS - PAGE_SHIFT)
     950             : 
     951             : #define NR_MEM_SECTIONS         (1UL << SECTIONS_SHIFT)
     952             : 
     953             : #define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
     954             : #define PAGE_SECTION_MASK       (~(PAGES_PER_SECTION-1))
     955             : 
     956             : #define SECTION_BLOCKFLAGS_BITS \
     957             :         ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
     958             : 
     959             : #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
     960             : #error Allocator MAX_ORDER exceeds SECTION_SIZE
     961             : #endif
     962             : 
     963             : struct page;
     964             : struct page_cgroup;
     965             : struct mem_section {
     966             :         /*
     967             :          * This is, logically, a pointer to an array of struct
     968             :          * pages.  However, it is stored with some other magic.
     969             :          * (see sparse.c::sparse_init_one_section())
     970             :          *
     971             :          * Additionally during early boot we encode node id of
     972             :          * the location of the section here to guide allocation.
     973             :          * (see sparse.c::memory_present())
     974             :          *
     975             :          * Making it a UL at least makes someone do a cast
     976             :          * before using it wrong.
     977             :          */
     978             :         unsigned long section_mem_map;
     979             : 
     980             :         /* See declaration of similar field in struct zone */
     981             :         unsigned long *pageblock_flags;
     982             : #ifdef CONFIG_CGROUP_MEM_RES_CTLR
     983             :         /*
     984             :          * If !SPARSEMEM, pgdat doesn't have page_cgroup pointer. We use
     985             :          * section. (see memcontrol.h/page_cgroup.h about this.)
     986             :          */
     987             :         struct page_cgroup *page_cgroup;
     988             :         unsigned long pad;
     989             : #endif
     990             : };
     991             : 
     992             : #ifdef CONFIG_SPARSEMEM_EXTREME
     993             : #define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
     994             : #else
     995             : #define SECTIONS_PER_ROOT       1
     996             : #endif
     997             : 
     998             : #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
     999             : #define NR_SECTION_ROOTS        (NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
    1000             : #define SECTION_ROOT_MASK       (SECTIONS_PER_ROOT - 1)
    1001             : 
    1002             : #ifdef CONFIG_SPARSEMEM_EXTREME
    1003           1 : extern struct mem_section *mem_section[NR_SECTION_ROOTS];
    1004             : #else
    1005             : extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
    1006             : #endif
    1007             : 
    1008             : static inline struct mem_section *__nr_to_section(unsigned long nr)
    1009             : {
    1010           8 :         if (!mem_section[SECTION_NR_TO_ROOT(nr)])
    1011           4 :                 return NULL;
    1012           4 :         return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
    1013             : }
    1014             : extern int __section_nr(struct mem_section* ms);
    1015             : extern unsigned long usemap_size(void);
    1016             : 
    1017             : /*
    1018             :  * We use the lower bits of the mem_map pointer to store
    1019             :  * a little bit of information.  There should be at least
    1020             :  * 3 bits here due to 32-bit alignment.
    1021             :  */
    1022             : #define SECTION_MARKED_PRESENT  (1UL<<0)
    1023             : #define SECTION_HAS_MEM_MAP     (1UL<<1)
    1024             : #define SECTION_MAP_LAST_BIT    (1UL<<2)
    1025             : #define SECTION_MAP_MASK        (~(SECTION_MAP_LAST_BIT-1))
    1026             : #define SECTION_NID_SHIFT       2
    1027             : 
    1028             : static inline struct page *__section_mem_map_addr(struct mem_section *section)
    1029             : {
    1030           8 :         unsigned long map = section->section_mem_map;
    1031           4 :         map &= SECTION_MAP_MASK;
    1032           4 :         return (struct page *)map;
    1033             : }
    1034             : 
    1035             : static inline int present_section(struct mem_section *section)
    1036             : {
    1037             :         return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
    1038             : }
    1039             : 
    1040             : static inline int present_section_nr(unsigned long nr)
    1041             : {
    1042             :         return present_section(__nr_to_section(nr));
    1043             : }
    1044             : 
    1045             : static inline int valid_section(struct mem_section *section)
    1046             : {
    1047             :         return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
    1048             : }
    1049             : 
    1050             : static inline int valid_section_nr(unsigned long nr)
    1051             : {
    1052             :         return valid_section(__nr_to_section(nr));
    1053             : }
    1054             : 
    1055             : static inline struct mem_section *__pfn_to_section(unsigned long pfn)
    1056             : {
    1057           4 :         return __nr_to_section(pfn_to_section_nr(pfn));
    1058             : }
    1059             : 
    1060             : static inline int pfn_valid(unsigned long pfn)
    1061             : {
    1062             :         if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
    1063             :                 return 0;
    1064             :         return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
    1065             : }
    1066             : 
    1067             : static inline int pfn_present(unsigned long pfn)
    1068             : {
    1069             :         if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
    1070             :                 return 0;
    1071             :         return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
    1072             : }
    1073             : 
    1074             : /*
    1075             :  * These are _only_ used during initialisation, therefore they
    1076             :  * can use __initdata ...  They could have names to indicate
    1077             :  * this restriction.
    1078             :  */
    1079             : #ifdef CONFIG_NUMA
    1080             : #define pfn_to_nid(pfn)                                                 \
    1081             : ({                                                                      \
    1082             :         unsigned long __pfn_to_nid_pfn = (pfn);                         \
    1083             :         page_to_nid(pfn_to_page(__pfn_to_nid_pfn));                     \
    1084             : })
    1085             : #else
    1086             : #define pfn_to_nid(pfn)         (0)
    1087             : #endif
    1088             : 
    1089             : #define early_pfn_valid(pfn)    pfn_valid(pfn)
    1090             : void sparse_init(void);
    1091             : #else
    1092             : #define sparse_init()   do {} while (0)
    1093             : #define sparse_index_init(_sec, _nid)  do {} while (0)
    1094             : #endif /* CONFIG_SPARSEMEM */
    1095             : 
    1096             : #ifdef CONFIG_NODES_SPAN_OTHER_NODES
    1097             : bool early_pfn_in_nid(unsigned long pfn, int nid);
    1098             : #else
    1099             : #define early_pfn_in_nid(pfn, nid)      (1)
    1100             : #endif
    1101             : 
    1102             : #ifndef early_pfn_valid
    1103             : #define early_pfn_valid(pfn)    (1)
    1104             : #endif
    1105             : 
    1106             : void memory_present(int nid, unsigned long start, unsigned long end);
    1107             : unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
    1108             : 
    1109             : /*
    1110             :  * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
    1111             :  * need to check pfn validility within that MAX_ORDER_NR_PAGES block.
    1112             :  * pfn_valid_within() should be used in this case; we optimise this away
    1113             :  * when we have no holes within a MAX_ORDER_NR_PAGES block.
    1114             :  */
    1115             : #ifdef CONFIG_HOLES_IN_ZONE
    1116             : #define pfn_valid_within(pfn) pfn_valid(pfn)
    1117             : #else
    1118             : #define pfn_valid_within(pfn) (1)
    1119             : #endif
    1120             : 
    1121             : #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
    1122             : /*
    1123             :  * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
    1124             :  * associated with it or not. In FLATMEM, it is expected that holes always
    1125             :  * have valid memmap as long as there is valid PFNs either side of the hole.
    1126             :  * In SPARSEMEM, it is assumed that a valid section has a memmap for the
    1127             :  * entire section.
    1128             :  *
    1129             :  * However, an ARM, and maybe other embedded architectures in the future
    1130             :  * free memmap backing holes to save memory on the assumption the memmap is
    1131             :  * never used. The page_zone linkages are then broken even though pfn_valid()
    1132             :  * returns true. A walker of the full memmap must then do this additional
    1133             :  * check to ensure the memmap they are looking at is sane by making sure
    1134             :  * the zone and PFN linkages are still valid. This is expensive, but walkers
    1135             :  * of the full memmap are extremely rare.
    1136             :  */
    1137             : int memmap_valid_within(unsigned long pfn,
    1138             :                                         struct page *page, struct zone *zone);
    1139             : #else
    1140             : static inline int memmap_valid_within(unsigned long pfn,
    1141             :                                         struct page *page, struct zone *zone)
    1142             : {
    1143             :         return 1;
    1144             : }
    1145             : #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
    1146             : 
    1147             : #endif /* !__GENERATING_BOUNDS.H */
    1148             : #endif /* !__ASSEMBLY__ */
    1149             : #endif /* _LINUX_MMZONE_H */

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