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 /*
  28  * Each physical page in the system has a struct page associated with
  29  * it to keep track of whatever it is we are using the page for at the
  30  * moment. Note that we have no way to track which tasks are using
  31  * a page, though if it is a pagecache page, rmap structures can tell us
  32  * who is mapping it.
  33  */
  34 struct page {
  35         unsigned long flags;            /* Atomic flags, some possibly
  36                                          * updated asynchronously */
  37         atomic_t _count;                /* Usage count, see below. */
  38         union {
  39                 /*
  40                  * Count of ptes mapped in
  41                  * mms, to show when page is
  42                  * mapped & limit reverse map
  43                  * searches.
  44                  *
  45                  * Used also for tail pages
  46                  * refcounting instead of
  47                  * _count. Tail pages cannot
  48                  * be mapped and keeping the
  49                  * tail page _count zero at
  50                  * all times guarantees
  51                  * get_page_unless_zero() will
  52                  * never succeed on tail
  53                  * pages.
  54                  */
  55                 atomic_t _mapcount;
  56
  57                 struct {                /* SLUB */
  58                         u16 inuse;
  59                         u16 objects;
  60                 };
  61         };
  62         union {
  63             struct {
  64                 unsigned long private;          /* Mapping-private opaque data:
  65                                                  * usually used for buffer_heads
  66                                                  * if PagePrivate set; used for
  67                                                  * swp_entry_t if PageSwapCache;
  68                                                  * indicates order in the buddy
  69                                                  * system if PG_buddy is set.
  70                                                  */
  71                 struct address_space *mapping;  /* If low bit clear, points to
  72                                                  * inode address_space, or NULL.
  73                                                  * If page mapped as anonymous
  74                                                  * memory, low bit is set, and
  75                                                  * it points to anon_vma object:
  76                                                  * see PAGE_MAPPING_ANON below.
  77                                                  */
  78             };
  79 #if USE_SPLIT_PTLOCKS
  80             spinlock_t ptl;
  81 #endif
  82             struct kmem_cache *slab;    /* SLUB: Pointer to slab */
  83             struct page *first_page;    /* Compound tail pages */
  84         };
  85         union {
  86                 pgoff_t index;          /* Our offset within mapping. */
  87                 void *freelist;         /* SLUB: freelist req. slab lock */
  88         };
  89         struct list_head lru;           /* Pageout list, eg. active_list
  90                                          * protected by zone->lru_lock !
  91                                          */
  92         /*
  93          * On machines where all RAM is mapped into kernel address space,
  94          * we can simply calculate the virtual address. On machines with
  95          * highmem some memory is mapped into kernel virtual memory
  96          * dynamically, so we need a place to store that address.
  97          * Note that this field could be 16 bits on x86 ... ;)
  98          *
  99          * Architectures with slow multiplication can define
 100          * WANT_PAGE_VIRTUAL in asm/page.h
 101          */
 102 #if defined(WANT_PAGE_VIRTUAL)
 103         void *virtual;                  /* Kernel virtual address (NULL if
 104                                            not kmapped, ie. highmem) */
 105 #endif /* WANT_PAGE_VIRTUAL */
 106 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 107         unsigned long debug_flags;      /* Use atomic bitops on this */
 108 #endif
 109
 110 #ifdef CONFIG_KMEMCHECK
 111         /*
 112          * kmemcheck wants to track the status of each byte in a page; this
 113          * is a pointer to such a status block. NULL if not tracked.
 114          */
 115         void *shadow;
 116 #endif
 117 };
 118
 119 typedef unsigned long __nocast vm_flags_t;
 120
 121 /*
 122  * A region containing a mapping of a non-memory backed file under NOMMU
 123  * conditions.  These are held in a global tree and are pinned by the VMAs that
 124  * map parts of them.
 125  */
 126 struct vm_region {
 127         struct rb_node  vm_rb;          /* link in global region tree */
 128         vm_flags_t      vm_flags;       /* VMA vm_flags */
 129         unsigned long   vm_start;       /* start address of region */
 130         unsigned long   vm_end;         /* region initialised to here */
 131         unsigned long   vm_top;         /* region allocated to here */
 132         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 133         struct file     *vm_file;       /* the backing file or NULL */
 134
 135         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 136         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 137                                                 * this region */
 138 };
 139
 140 /*
 141  * This struct defines a memory VMM memory area. There is one of these
 142  * per VM-area/task.  A VM area is any part of the process virtual memory
 143  * space that has a special rule for the page-fault handlers (ie a shared
 144  * library, the executable area etc).
 145  */
 146 struct vm_area_struct {
 147         struct mm_struct * vm_mm;       /* The address space we belong to. */
 148         unsigned long vm_start;         /* Our start address within vm_mm. */
 149         unsigned long vm_end;           /* The first byte after our end address
 150                                            within vm_mm. */
 151
 152         /* linked list of VM areas per task, sorted by address */
 153         struct vm_area_struct *vm_next, *vm_prev;
 154
 155         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 156         unsigned long vm_flags;         /* Flags, see mm.h. */
 157
 158         struct rb_node vm_rb;
 159
 160         /*
 161          * For areas with an address space and backing store,
 162          * linkage into the address_space->i_mmap prio tree, or
 163          * linkage to the list of like vmas hanging off its node, or
 164          * linkage of vma in the address_space->i_mmap_nonlinear list.
 165          */
 166         union {
 167                 struct {
 168                         struct list_head list;
 169                         void *parent;   /* aligns with prio_tree_node parent */
 170                         struct vm_area_struct *head;
 171                 } vm_set;
 172
 173                 struct raw_prio_tree_node prio_tree_node;
 174         } shared;
 175
 176         /*
 177          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 178          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 179          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 180          * or brk vma (with NULL file) can only be in an anon_vma list.
 181          */
 182         struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 183                                           * page_table_lock */
 184         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 185
 186         /* Function pointers to deal with this struct. */
 187         const struct vm_operations_struct *vm_ops;
 188
 189         /* Information about our backing store: */
 190         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 191                                            units, *not* PAGE_CACHE_SIZE */
 192         struct file * vm_file;          /* File we map to (can be NULL). */
 193         void * vm_private_data;         /* was vm_pte (shared mem) */
 194
 195 #ifndef CONFIG_MMU
 196         struct vm_region *vm_region;    /* NOMMU mapping region */
 197 #endif
 198 #ifdef CONFIG_NUMA
 199         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 200 #endif
 201 };
 202
 203 struct core_thread {
 204         struct task_struct *task;
 205         struct core_thread *next;
 206 };
 207
 208 struct core_state {
 209         atomic_t nr_threads;
 210         struct core_thread dumper;
 211         struct completion startup;
 212 };
 213
 214 enum {
 215         MM_FILEPAGES,
 216         MM_ANONPAGES,
 217         MM_SWAPENTS,
 218         NR_MM_COUNTERS
 219 };
 220
 221 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 222 #define SPLIT_RSS_COUNTING
 223 /* per-thread cached information, */
 224 struct task_rss_stat {
 225         int events;     /* for synchronization threshold */
 226         int count[NR_MM_COUNTERS];
 227 };
 228 #endif /* USE_SPLIT_PTLOCKS */
 229
 230 struct mm_rss_stat {
 231         atomic_long_t count[NR_MM_COUNTERS];
 232 };
 233
 234 struct mm_struct {
 235         struct vm_area_struct * mmap;           /* list of VMAs */
 236         struct rb_root mm_rb;
 237         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 238 #ifdef CONFIG_MMU
 239         unsigned long (*get_unmapped_area) (struct file *filp,
 240                                 unsigned long addr, unsigned long len,
 241                                 unsigned long pgoff, unsigned long flags);
 242         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 243 #endif
 244         unsigned long mmap_base;                /* base of mmap area */
 245         unsigned long task_size;                /* size of task vm space */
 246         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 247         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 248         pgd_t * pgd;
 249         atomic_t mm_users;                      /* How many users with user space? */
 250         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 251         int map_count;                          /* number of VMAs */
 252
 253         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 254         struct rw_semaphore mmap_sem;
 255
 256         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 257                                                  * together off init_mm.mmlist, and are protected
 258                                                  * by mmlist_lock
 259                                                  */
 260
 261
 262         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 263         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 264
 265         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 266         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 267         unsigned long start_code, end_code, start_data, end_data;
 268         unsigned long start_brk, brk, start_stack;
 269         unsigned long arg_start, arg_end, env_start, env_end;
 270
 271         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 272
 273         /*
 274          * Special counters, in some configurations protected by the
 275          * page_table_lock, in other configurations by being atomic.
 276          */
 277         struct mm_rss_stat rss_stat;
 278
 279         struct linux_binfmt *binfmt;
 280
 281         cpumask_var_t cpu_vm_mask_var;
 282
 283         /* Architecture-specific MM context */
 284         mm_context_t context;
 285
 286         /* Swap token stuff */
 287         /*
 288          * Last value of global fault stamp as seen by this process.
 289          * In other words, this value gives an indication of how long
 290          * it has been since this task got the token.
 291          * Look at mm/thrash.c
 292          */
 293         unsigned int faultstamp;
 294         unsigned int token_priority;
 295         unsigned int last_interval;
 296
 297         /* How many tasks sharing this mm are OOM_DISABLE */
 298         atomic_t oom_disable_count;
 299
 300         unsigned long flags; /* Must use atomic bitops to access the bits */
 301
 302         struct core_state *core_state; /* coredumping support */
 303 #ifdef CONFIG_AIO
 304         spinlock_t              ioctx_lock;
 305         struct hlist_head       ioctx_list;
 306 #endif
 307 #ifdef CONFIG_MM_OWNER
 308         /*
 309          * "owner" points to a task that is regarded as the canonical
 310          * user/owner of this mm. All of the following must be true in
 311          * order for it to be changed:
 312          *
 313          * current == mm->owner
 314          * current->mm != mm
 315          * new_owner->mm == mm
 316          * new_owner->alloc_lock is held
 317          */
 318         struct task_struct __rcu *owner;
 319 #endif
 320
 321         /* store ref to file /proc/<pid>/exe symlink points to */
 322         struct file *exe_file;
 323         unsigned long num_exe_file_vmas;
 324 #ifdef CONFIG_MMU_NOTIFIER
 325         struct mmu_notifier_mm *mmu_notifier_mm;
 326 #endif
 327 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 328         pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 329 #endif
 330 #ifdef CONFIG_CPUMASK_OFFSTACK
 331         struct cpumask cpumask_allocation;
 332 #endif
 333 };
 334
 335 static inline void mm_init_cpumask(struct mm_struct *mm)
 336 {
 337 #ifdef CONFIG_CPUMASK_OFFSTACK
 338         mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 339 #endif
 340 }
 341
 342 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 343 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 344 {
 345         return mm->cpu_vm_mask_var;
 346 }
 347
 348 #endif /* _LINUX_MM_TYPES_H */