linux/include/linux/mm_types.h
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   1#ifndef _LINUX_MM_TYPES_H
   2#define _LINUX_MM_TYPES_H
   3
   4#include <linux/auxvec.h>
   5#include <linux/types.h>
   6#include <linux/threads.h>
   7#include <linux/list.h>
   8#include <linux/spinlock.h>
   9#include <linux/prio_tree.h>
  10#include <linux/rbtree.h>
  11#include <linux/rwsem.h>
  12#include <linux/completion.h>
  13#include <asm/page.h>
  14#include <asm/mmu.h>
  15
  16#ifndef AT_VECTOR_SIZE_ARCH
  17#define AT_VECTOR_SIZE_ARCH 0
  18#endif
  19#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
  20
  21struct address_space;
  22
  23#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
  24typedef atomic_long_t mm_counter_t;
  25#else  /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
  26typedef unsigned long mm_counter_t;
  27#endif /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
  28
  29/*
  30 * Each physical page in the system has a struct page associated with
  31 * it to keep track of whatever it is we are using the page for at the
  32 * moment. Note that we have no way to track which tasks are using
  33 * a page, though if it is a pagecache page, rmap structures can tell us
  34 * who is mapping it.
  35 */
  36struct page {
  37        unsigned long flags;            /* Atomic flags, some possibly
  38                                         * updated asynchronously */
  39        atomic_t _count;                /* Usage count, see below. */
  40        union {
  41                atomic_t _mapcount;     /* Count of ptes mapped in mms,
  42                                         * to show when page is mapped
  43                                         * & limit reverse map searches.
  44                                         */
  45                unsigned int inuse;     /* SLUB: Nr of objects */
  46        };
  47        union {
  48            struct {
  49                unsigned long private;          /* Mapping-private opaque data:
  50                                                 * usually used for buffer_heads
  51                                                 * if PagePrivate set; used for
  52                                                 * swp_entry_t if PageSwapCache;
  53                                                 * indicates order in the buddy
  54                                                 * system if PG_buddy is set.
  55                                                 */
  56                struct address_space *mapping;  /* If low bit clear, points to
  57                                                 * inode address_space, or NULL.
  58                                                 * If page mapped as anonymous
  59                                                 * memory, low bit is set, and
  60                                                 * it points to anon_vma object:
  61                                                 * see PAGE_MAPPING_ANON below.
  62                                                 */
  63            };
  64#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
  65            spinlock_t ptl;
  66#endif
  67            struct kmem_cache *slab;    /* SLUB: Pointer to slab */
  68            struct page *first_page;    /* Compound tail pages */
  69        };
  70        union {
  71                pgoff_t index;          /* Our offset within mapping. */
  72                void *freelist;         /* SLUB: freelist req. slab lock */
  73        };
  74        struct list_head lru;           /* Pageout list, eg. active_list
  75                                         * protected by zone->lru_lock !
  76                                         */
  77        /*
  78         * On machines where all RAM is mapped into kernel address space,
  79         * we can simply calculate the virtual address. On machines with
  80         * highmem some memory is mapped into kernel virtual memory
  81         * dynamically, so we need a place to store that address.
  82         * Note that this field could be 16 bits on x86 ... ;)
  83         *
  84         * Architectures with slow multiplication can define
  85         * WANT_PAGE_VIRTUAL in asm/page.h
  86         */
  87#if defined(WANT_PAGE_VIRTUAL)
  88        void *virtual;                  /* Kernel virtual address (NULL if
  89                                           not kmapped, ie. highmem) */
  90#endif /* WANT_PAGE_VIRTUAL */
  91};
  92
  93/*
  94 * This struct defines a memory VMM memory area. There is one of these
  95 * per VM-area/task.  A VM area is any part of the process virtual memory
  96 * space that has a special rule for the page-fault handlers (ie a shared
  97 * library, the executable area etc).
  98 */
  99struct vm_area_struct {
 100        struct mm_struct * vm_mm;       /* The address space we belong to. */
 101        unsigned long vm_start;         /* Our start address within vm_mm. */
 102        unsigned long vm_end;           /* The first byte after our end address
 103                                           within vm_mm. */
 104
 105        /* linked list of VM areas per task, sorted by address */
 106        struct vm_area_struct *vm_next;
 107
 108        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 109        unsigned long vm_flags;         /* Flags, listed below. */
 110
 111        struct rb_node vm_rb;
 112
 113        /*
 114         * For areas with an address space and backing store,
 115         * linkage into the address_space->i_mmap prio tree, or
 116         * linkage to the list of like vmas hanging off its node, or
 117         * linkage of vma in the address_space->i_mmap_nonlinear list.
 118         */
 119        union {
 120                struct {
 121                        struct list_head list;
 122                        void *parent;   /* aligns with prio_tree_node parent */
 123                        struct vm_area_struct *head;
 124                } vm_set;
 125
 126                struct raw_prio_tree_node prio_tree_node;
 127        } shared;
 128
 129        /*
 130         * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 131         * list, after a COW of one of the file pages.  A MAP_SHARED vma
 132         * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 133         * or brk vma (with NULL file) can only be in an anon_vma list.
 134         */
 135        struct list_head anon_vma_node; /* Serialized by anon_vma->lock */
 136        struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 137
 138        /* Function pointers to deal with this struct. */
 139        struct vm_operations_struct * vm_ops;
 140
 141        /* Information about our backing store: */
 142        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 143                                           units, *not* PAGE_CACHE_SIZE */
 144        struct file * vm_file;          /* File we map to (can be NULL). */
 145        void * vm_private_data;         /* was vm_pte (shared mem) */
 146        unsigned long vm_truncate_count;/* truncate_count or restart_addr */
 147
 148#ifndef CONFIG_MMU
 149        atomic_t vm_usage;              /* refcount (VMAs shared if !MMU) */
 150#endif
 151#ifdef CONFIG_NUMA
 152        struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 153#endif
 154};
 155
 156struct mm_struct {
 157        struct vm_area_struct * mmap;           /* list of VMAs */
 158        struct rb_root mm_rb;
 159        struct vm_area_struct * mmap_cache;     /* last find_vma result */
 160        unsigned long (*get_unmapped_area) (struct file *filp,
 161                                unsigned long addr, unsigned long len,
 162                                unsigned long pgoff, unsigned long flags);
 163        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 164        unsigned long mmap_base;                /* base of mmap area */
 165        unsigned long task_size;                /* size of task vm space */
 166        unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 167        unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 168        pgd_t * pgd;
 169        atomic_t mm_users;                      /* How many users with user space? */
 170        atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 171        int map_count;                          /* number of VMAs */
 172        struct rw_semaphore mmap_sem;
 173        spinlock_t page_table_lock;             /* Protects page tables and some counters */
 174
 175        struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 176                                                 * together off init_mm.mmlist, and are protected
 177                                                 * by mmlist_lock
 178                                                 */
 179
 180        /* Special counters, in some configurations protected by the
 181         * page_table_lock, in other configurations by being atomic.
 182         */
 183        mm_counter_t _file_rss;
 184        mm_counter_t _anon_rss;
 185
 186        unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 187        unsigned long hiwater_vm;       /* High-water virtual memory usage */
 188
 189        unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 190        unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 191        unsigned long start_code, end_code, start_data, end_data;
 192        unsigned long start_brk, brk, start_stack;
 193        unsigned long arg_start, arg_end, env_start, env_end;
 194
 195        unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 196
 197        cpumask_t cpu_vm_mask;
 198
 199        /* Architecture-specific MM context */
 200        mm_context_t context;
 201
 202        /* Swap token stuff */
 203        /*
 204         * Last value of global fault stamp as seen by this process.
 205         * In other words, this value gives an indication of how long
 206         * it has been since this task got the token.
 207         * Look at mm/thrash.c
 208         */
 209        unsigned int faultstamp;
 210        unsigned int token_priority;
 211        unsigned int last_interval;
 212
 213        unsigned long flags; /* Must use atomic bitops to access the bits */
 214
 215        /* coredumping support */
 216        int core_waiters;
 217        struct completion *core_startup_done, core_done;
 218
 219        /* aio bits */
 220        rwlock_t                ioctx_list_lock;
 221        struct kioctx           *ioctx_list;
 222};
 223
 224#endif /* _LINUX_MM_TYPES_H */
 225