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 <linux/cpumask.h>
  14 #include <linux/page-debug-flags.h>
  15 #include <asm/page.h>
  16 #include <asm/mmu.h>
  17
  18 #ifndef AT_VECTOR_SIZE_ARCH
  19 #define AT_VECTOR_SIZE_ARCH 0
  20 #endif
  21 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
  22
  23 struct address_space;
  24
  25 #define USE_SPLIT_PTLOCKS       (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
  26
  27 #if USE_SPLIT_PTLOCKS
  28 typedef atomic_long_t mm_counter_t;
  29 #else  /* !USE_SPLIT_PTLOCKS */
  30 typedef unsigned long mm_counter_t;
  31 #endif /* !USE_SPLIT_PTLOCKS */
  32
  33 /*
  34  * Each physical page in the system has a struct page associated with
  35  * it to keep track of whatever it is we are using the page for at the
  36  * moment. Note that we have no way to track which tasks are using
  37  * a page, though if it is a pagecache page, rmap structures can tell us
  38  * who is mapping it.
  39  */
  40 struct page {
  41         unsigned long flags;            /* Atomic flags, some possibly
  42                                          * updated asynchronously */
  43         atomic_t _count;                /* Usage count, see below. */
  44         union {
  45                 atomic_t _mapcount;     /* Count of ptes mapped in mms,
  46                                          * to show when page is mapped
  47                                          * & limit reverse map searches.
  48                                          */
  49                 struct {                /* SLUB */
  50                         u16 inuse;
  51                         u16 objects;
  52                 };
  53         };
  54         union {
  55             struct {
  56                 unsigned long private;          /* Mapping-private opaque data:
  57                                                  * usually used for buffer_heads
  58                                                  * if PagePrivate set; used for
  59                                                  * swp_entry_t if PageSwapCache;
  60                                                  * indicates order in the buddy
  61                                                  * system if PG_buddy is set.
  62                                                  */
  63                 struct address_space *mapping;  /* If low bit clear, points to
  64                                                  * inode address_space, or NULL.
  65                                                  * If page mapped as anonymous
  66                                                  * memory, low bit is set, and
  67                                                  * it points to anon_vma object:
  68                                                  * see PAGE_MAPPING_ANON below.
  69                                                  */
  70             };
  71 #if USE_SPLIT_PTLOCKS
  72             spinlock_t ptl;
  73 #endif
  74             struct kmem_cache *slab;    /* SLUB: Pointer to slab */
  75             struct page *first_page;    /* Compound tail pages */
  76         };
  77         union {
  78                 pgoff_t index;          /* Our offset within mapping. */
  79                 void *freelist;         /* SLUB: freelist req. slab lock */
  80         };
  81         struct list_head lru;           /* Pageout list, eg. active_list
  82                                          * protected by zone->lru_lock !
  83                                          */
  84         /*
  85          * On machines where all RAM is mapped into kernel address space,
  86          * we can simply calculate the virtual address. On machines with
  87          * highmem some memory is mapped into kernel virtual memory
  88          * dynamically, so we need a place to store that address.
  89          * Note that this field could be 16 bits on x86 ... ;)
  90          *
  91          * Architectures with slow multiplication can define
  92          * WANT_PAGE_VIRTUAL in asm/page.h
  93          */
  94 #if defined(WANT_PAGE_VIRTUAL)
  95         void *virtual;                  /* Kernel virtual address (NULL if
  96                                            not kmapped, ie. highmem) */
  97 #endif /* WANT_PAGE_VIRTUAL */
  98 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
  99         unsigned long debug_flags;      /* Use atomic bitops on this */
 100 #endif
 101
 102 #ifdef CONFIG_KMEMCHECK
 103         /*
 104          * kmemcheck wants to track the status of each byte in a page; this
 105          * is a pointer to such a status block. NULL if not tracked.
 106          */
 107         void *shadow;
 108 #endif
 109 };
 110
 111 /*
 112  * A region containing a mapping of a non-memory backed file under NOMMU
 113  * conditions.  These are held in a global tree and are pinned by the VMAs that
 114  * map parts of them.
 115  */
 116 struct vm_region {
 117         struct rb_node  vm_rb;          /* link in global region tree */
 118         unsigned long   vm_flags;       /* VMA vm_flags */
 119         unsigned long   vm_start;       /* start address of region */
 120         unsigned long   vm_end;         /* region initialised to here */
 121         unsigned long   vm_top;         /* region allocated to here */
 122         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 123         struct file     *vm_file;       /* the backing file or NULL */
 124
 125         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 126         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 127                                                 * this region */
 128 };
 129
 130 /*
 131  * This struct defines a memory VMM memory area. There is one of these
 132  * per VM-area/task.  A VM area is any part of the process virtual memory
 133  * space that has a special rule for the page-fault handlers (ie a shared
 134  * library, the executable area etc).
 135  */
 136 struct vm_area_struct {
 137         struct mm_struct * vm_mm;       /* The address space we belong to. */
 138         unsigned long vm_start;         /* Our start address within vm_mm. */
 139         unsigned long vm_end;           /* The first byte after our end address
 140                                            within vm_mm. */
 141
 142         /* linked list of VM areas per task, sorted by address */
 143         struct vm_area_struct *vm_next;
 144
 145         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 146         unsigned long vm_flags;         /* Flags, see mm.h. */
 147
 148         struct rb_node vm_rb;
 149
 150         /*
 151          * For areas with an address space and backing store,
 152          * linkage into the address_space->i_mmap prio tree, or
 153          * linkage to the list of like vmas hanging off its node, or
 154          * linkage of vma in the address_space->i_mmap_nonlinear list.
 155          */
 156         union {
 157                 struct {
 158                         struct list_head list;
 159                         void *parent;   /* aligns with prio_tree_node parent */
 160                         struct vm_area_struct *head;
 161                 } vm_set;
 162
 163                 struct raw_prio_tree_node prio_tree_node;
 164         } shared;
 165
 166         /*
 167          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 168          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 169          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 170          * or brk vma (with NULL file) can only be in an anon_vma list.
 171          */
 172         struct list_head anon_vma_node; /* Serialized by anon_vma->lock */
 173         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 174
 175         /* Function pointers to deal with this struct. */
 176         const struct vm_operations_struct *vm_ops;
 177
 178         /* Information about our backing store: */
 179         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 180                                            units, *not* PAGE_CACHE_SIZE */
 181         struct file * vm_file;          /* File we map to (can be NULL). */
 182         void * vm_private_data;         /* was vm_pte (shared mem) */
 183         unsigned long vm_truncate_count;/* truncate_count or restart_addr */
 184
 185 #ifndef CONFIG_MMU
 186         struct vm_region *vm_region;    /* NOMMU mapping region */
 187 #endif
 188 #ifdef CONFIG_NUMA
 189         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 190 #endif
 191 };
 192
 193 struct core_thread {
 194         struct task_struct *task;
 195         struct core_thread *next;
 196 };
 197
 198 struct core_state {
 199         atomic_t nr_threads;
 200         struct core_thread dumper;
 201         struct completion startup;
 202 };
 203
 204 struct mm_struct {
 205         struct vm_area_struct * mmap;           /* list of VMAs */
 206         struct rb_root mm_rb;
 207         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 208 #ifdef CONFIG_MMU
 209         unsigned long (*get_unmapped_area) (struct file *filp,
 210                                 unsigned long addr, unsigned long len,
 211                                 unsigned long pgoff, unsigned long flags);
 212         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 213 #endif
 214         unsigned long mmap_base;                /* base of mmap area */
 215         unsigned long task_size;                /* size of task vm space */
 216         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 217         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 218         pgd_t * pgd;
 219         atomic_t mm_users;                      /* How many users with user space? */
 220         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 221         int map_count;                          /* number of VMAs */
 222         struct rw_semaphore mmap_sem;
 223         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 224
 225         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 226                                                  * together off init_mm.mmlist, and are protected
 227                                                  * by mmlist_lock
 228                                                  */
 229
 230         /* Special counters, in some configurations protected by the
 231          * page_table_lock, in other configurations by being atomic.
 232          */
 233         mm_counter_t _file_rss;
 234         mm_counter_t _anon_rss;
 235
 236         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 237         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 238
 239         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 240         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 241         unsigned long start_code, end_code, start_data, end_data;
 242         unsigned long start_brk, brk, start_stack;
 243         unsigned long arg_start, arg_end, env_start, env_end;
 244
 245         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 246
 247         struct linux_binfmt *binfmt;
 248
 249         cpumask_t cpu_vm_mask;
 250
 251         /* Architecture-specific MM context */
 252         mm_context_t context;
 253
 254         /* Swap token stuff */
 255         /*
 256          * Last value of global fault stamp as seen by this process.
 257          * In other words, this value gives an indication of how long
 258          * it has been since this task got the token.
 259          * Look at mm/thrash.c
 260          */
 261         unsigned int faultstamp;
 262         unsigned int token_priority;
 263         unsigned int last_interval;
 264
 265         unsigned long flags; /* Must use atomic bitops to access the bits */
 266
 267         struct core_state *core_state; /* coredumping support */
 268 #ifdef CONFIG_AIO
 269         spinlock_t              ioctx_lock;
 270         struct hlist_head       ioctx_list;
 271 #endif
 272 #ifdef CONFIG_MM_OWNER
 273         /*
 274          * "owner" points to a task that is regarded as the canonical
 275          * user/owner of this mm. All of the following must be true in
 276          * order for it to be changed:
 277          *
 278          * current == mm->owner
 279          * current->mm != mm
 280          * new_owner->mm == mm
 281          * new_owner->alloc_lock is held
 282          */
 283         struct task_struct *owner;
 284 #endif
 285
 286 #ifdef CONFIG_PROC_FS
 287         /* store ref to file /proc/<pid>/exe symlink points to */
 288         struct file *exe_file;
 289         unsigned long num_exe_file_vmas;
 290 #endif
 291 #ifdef CONFIG_MMU_NOTIFIER
 292         struct mmu_notifier_mm *mmu_notifier_mm;
 293 #endif
 294 };
 295
 296 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 297 #define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
 298
 299 #endif /* _LINUX_MM_TYPES_H */