include/linux/mm_types.h

   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
  21 struct address_space;
  22
  23 #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
  24 typedef atomic_long_t mm_counter_t;
  25 #else  /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
  26 typedef 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  */
  36 struct 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  */
  99 struct 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
 156 struct 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 */