include/linux/mm_types.h

   1 #ifndef _LINUX_MM_TYPES_H
   2 #define _LINUX_MM_TYPES_H
   3
   4 #include <linux/auxvec.h>       /* For AT_VECTOR_SIZE */
   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 struct address_space;
  17
  18 #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
  19 typedef atomic_long_t mm_counter_t;
  20 #else  /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
  21 typedef unsigned long mm_counter_t;
  22 #endif /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
  23
  24 /*
  25  * Each physical page in the system has a struct page associated with
  26  * it to keep track of whatever it is we are using the page for at the
  27  * moment. Note that we have no way to track which tasks are using
  28  * a page, though if it is a pagecache page, rmap structures can tell us
  29  * who is mapping it.
  30  */
  31 struct page {
  32         unsigned long flags;            /* Atomic flags, some possibly
  33                                          * updated asynchronously */
  34         atomic_t _count;                /* Usage count, see below. */
  35         union {
  36                 atomic_t _mapcount;     /* Count of ptes mapped in mms,
  37                                          * to show when page is mapped
  38                                          * & limit reverse map searches.
  39                                          */
  40                 struct {        /* SLUB uses */
  41                         short unsigned int inuse;
  42                         short unsigned int offset;
  43                 };
  44         };
  45         union {
  46             struct {
  47                 unsigned long private;          /* Mapping-private opaque data:
  48                                                  * usually used for buffer_heads
  49                                                  * if PagePrivate set; used for
  50                                                  * swp_entry_t if PageSwapCache;
  51                                                  * indicates order in the buddy
  52                                                  * system if PG_buddy is set.
  53                                                  */
  54                 struct address_space *mapping;  /* If low bit clear, points to
  55                                                  * inode address_space, or NULL.
  56                                                  * If page mapped as anonymous
  57                                                  * memory, low bit is set, and
  58                                                  * it points to anon_vma object:
  59                                                  * see PAGE_MAPPING_ANON below.
  60                                                  */
  61             };
  62 #if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
  63             spinlock_t ptl;
  64 #endif
  65             struct {                    /* SLUB uses */
  66                 void **lockless_freelist;
  67                 struct kmem_cache *slab;        /* Pointer to slab */
  68             };
  69             struct {
  70                 struct page *first_page;        /* Compound pages */
  71             };
  72         };
  73         union {
  74                 pgoff_t index;          /* Our offset within mapping. */
  75                 void *freelist;         /* SLUB: freelist req. slab lock */
  76         };
  77         struct list_head lru;           /* Pageout list, eg. active_list
  78                                          * protected by zone->lru_lock !
  79                                          */
  80         /*
  81          * On machines where all RAM is mapped into kernel address space,
  82          * we can simply calculate the virtual address. On machines with
  83          * highmem some memory is mapped into kernel virtual memory
  84          * dynamically, so we need a place to store that address.
  85          * Note that this field could be 16 bits on x86 ... ;)
  86          *
  87          * Architectures with slow multiplication can define
  88          * WANT_PAGE_VIRTUAL in asm/page.h
  89          */
  90 #if defined(WANT_PAGE_VIRTUAL)
  91         void *virtual;                  /* Kernel virtual address (NULL if
  92                                            not kmapped, ie. highmem) */
  93 #endif /* WANT_PAGE_VIRTUAL */
  94 };
  95
  96 /*
  97  * This struct defines a memory VMM memory area. There is one of these
  98  * per VM-area/task.  A VM area is any part of the process virtual memory
  99  * space that has a special rule for the page-fault handlers (ie a shared
 100  * library, the executable area etc).
 101  */
 102 struct vm_area_struct {
 103         struct mm_struct * vm_mm;       /* The address space we belong to. */
 104         unsigned long vm_start;         /* Our start address within vm_mm. */
 105         unsigned long vm_end;           /* The first byte after our end address
 106                                            within vm_mm. */
 107
 108         /* linked list of VM areas per task, sorted by address */
 109         struct vm_area_struct *vm_next;
 110
 111         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 112         unsigned long vm_flags;         /* Flags, listed below. */
 113
 114         struct rb_node vm_rb;
 115
 116         /*
 117          * For areas with an address space and backing store,
 118          * linkage into the address_space->i_mmap prio tree, or
 119          * linkage to the list of like vmas hanging off its node, or
 120          * linkage of vma in the address_space->i_mmap_nonlinear list.
 121          */
 122         union {
 123                 struct {
 124                         struct list_head list;
 125                         void *parent;   /* aligns with prio_tree_node parent */
 126                         struct vm_area_struct *head;
 127                 } vm_set;
 128
 129                 struct raw_prio_tree_node prio_tree_node;
 130         } shared;
 131
 132         /*
 133          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 134          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 135          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 136          * or brk vma (with NULL file) can only be in an anon_vma list.
 137          */
 138         struct list_head anon_vma_node; /* Serialized by anon_vma->lock */
 139         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 140
 141         /* Function pointers to deal with this struct. */
 142         struct vm_operations_struct * vm_ops;
 143
 144         /* Information about our backing store: */
 145         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 146                                            units, *not* PAGE_CACHE_SIZE */
 147         struct file * vm_file;          /* File we map to (can be NULL). */
 148         void * vm_private_data;         /* was vm_pte (shared mem) */
 149         unsigned long vm_truncate_count;/* truncate_count or restart_addr */
 150
 151 #ifndef CONFIG_MMU
 152         atomic_t vm_usage;              /* refcount (VMAs shared if !MMU) */
 153 #endif
 154 #ifdef CONFIG_NUMA
 155         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 156 #endif
 157 };
 158
 159 struct mm_struct {
 160         struct vm_area_struct * mmap;           /* list of VMAs */
 161         struct rb_root mm_rb;
 162         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 163         unsigned long (*get_unmapped_area) (struct file *filp,
 164                                 unsigned long addr, unsigned long len,
 165                                 unsigned long pgoff, unsigned long flags);
 166         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 167         unsigned long mmap_base;                /* base of mmap area */
 168         unsigned long task_size;                /* size of task vm space */
 169         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 170         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 171         pgd_t * pgd;
 172         atomic_t mm_users;                      /* How many users with user space? */
 173         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 174         int map_count;                          /* number of VMAs */
 175         struct rw_semaphore mmap_sem;
 176         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 177
 178         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 179                                                  * together off init_mm.mmlist, and are protected
 180                                                  * by mmlist_lock
 181                                                  */
 182
 183         /* Special counters, in some configurations protected by the
 184          * page_table_lock, in other configurations by being atomic.
 185          */
 186         mm_counter_t _file_rss;
 187         mm_counter_t _anon_rss;
 188
 189         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 190         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 191
 192         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 193         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 194         unsigned long start_code, end_code, start_data, end_data;
 195         unsigned long start_brk, brk, start_stack;
 196         unsigned long arg_start, arg_end, env_start, env_end;
 197
 198         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 199
 200         cpumask_t cpu_vm_mask;
 201
 202         /* Architecture-specific MM context */
 203         mm_context_t context;
 204
 205         /* Swap token stuff */
 206         /*
 207          * Last value of global fault stamp as seen by this process.
 208          * In other words, this value gives an indication of how long
 209          * it has been since this task got the token.
 210          * Look at mm/thrash.c
 211          */
 212         unsigned int faultstamp;
 213         unsigned int token_priority;
 214         unsigned int last_interval;
 215
 216         unsigned long flags; /* Must use atomic bitops to access the bits */
 217
 218         /* coredumping support */
 219         int core_waiters;
 220         struct completion *core_startup_done, core_done;
 221
 222         /* aio bits */
 223         rwlock_t                ioctx_list_lock;
 224         struct kioctx           *ioctx_list;
 225 };
 226
 227 #endif /* _LINUX_MM_TYPES_H */