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  * The objects in struct page are organized in double word blocks in
  35  * order to allows us to use atomic double word operations on portions
  36  * of struct page. That is currently only used by slub but the arrangement
  37  * allows the use of atomic double word operations on the flags/mapping
  38  * and lru list pointers also.
  39  */
  40 struct page {
  41         /* First double word block */
  42         unsigned long flags;            /* Atomic flags, some possibly
  43                                          * updated asynchronously */
  44         struct address_space *mapping;  /* If low bit clear, points to
  45                                          * inode address_space, or NULL.
  46                                          * If page mapped as anonymous
  47                                          * memory, low bit is set, and
  48                                          * it points to anon_vma object:
  49                                          * see PAGE_MAPPING_ANON below.
  50                                          */
  51         /* Second double word */
  52         struct {
  53                 union {
  54                         pgoff_t index;          /* Our offset within mapping. */
  55                         void *freelist;         /* slub first free object */
  56                 };
  57
  58                 union {
  59                         /* Used for cmpxchg_double in slub */
  60                         unsigned long counters;
  61
  62                         struct {
  63
  64                                 union {
  65                                         atomic_t _mapcount;     /* Count of ptes mapped in mms,
  66                                                          * to show when page is mapped
  67                                                          * & limit reverse map searches.
  68                                                          */
  69
  70                                         struct {
  71                                                 unsigned inuse:16;
  72                                                 unsigned objects:15;
  73                                                 unsigned frozen:1;
  74                                         };
  75                                 };
  76                                 atomic_t _count;                /* Usage count, see below. */
  77                         };
  78                 };
  79         };
  80
  81         /* Third double word block */
  82         struct list_head lru;           /* Pageout list, eg. active_list
  83                                          * protected by zone->lru_lock !
  84                                          */
  85
  86         /* Remainder is not double word aligned */
  87         union {
  88                 unsigned long private;          /* Mapping-private opaque data:
  89                                                  * usually used for buffer_heads
  90                                                  * if PagePrivate set; used for
  91                                                  * swp_entry_t if PageSwapCache;
  92                                                  * indicates order in the buddy
  93                                                  * system if PG_buddy is set.
  94                                                  */
  95 #if USE_SPLIT_PTLOCKS
  96                 spinlock_t ptl;
  97 #endif
  98                 struct kmem_cache *slab;        /* SLUB: Pointer to slab */
  99                 struct page *first_page;        /* Compound tail pages */
 100         };
 101
 102         /*
 103          * On machines where all RAM is mapped into kernel address space,
 104          * we can simply calculate the virtual address. On machines with
 105          * highmem some memory is mapped into kernel virtual memory
 106          * dynamically, so we need a place to store that address.
 107          * Note that this field could be 16 bits on x86 ... ;)
 108          *
 109          * Architectures with slow multiplication can define
 110          * WANT_PAGE_VIRTUAL in asm/page.h
 111          */
 112 #if defined(WANT_PAGE_VIRTUAL)
 113         void *virtual;                  /* Kernel virtual address (NULL if
 114                                            not kmapped, ie. highmem) */
 115 #endif /* WANT_PAGE_VIRTUAL */
 116 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 117         unsigned long debug_flags;      /* Use atomic bitops on this */
 118 #endif
 119
 120 #ifdef CONFIG_KMEMCHECK
 121         /*
 122          * kmemcheck wants to track the status of each byte in a page; this
 123          * is a pointer to such a status block. NULL if not tracked.
 124          */
 125         void *shadow;
 126 #endif
 127 }
 128 /*
 129  * If another subsystem starts using the double word pairing for atomic
 130  * operations on struct page then it must change the #if to ensure
 131  * proper alignment of the page struct.
 132  */
 133 #if defined(CONFIG_SLUB) && defined(CONFIG_CMPXCHG_LOCAL)
 134         __attribute__((__aligned__(2*sizeof(unsigned long))))
 135 #endif
 136 ;
 137
 138 typedef unsigned long __nocast vm_flags_t;
 139
 140 /*
 141  * A region containing a mapping of a non-memory backed file under NOMMU
 142  * conditions.  These are held in a global tree and are pinned by the VMAs that
 143  * map parts of them.
 144  */
 145 struct vm_region {
 146         struct rb_node  vm_rb;          /* link in global region tree */
 147         vm_flags_t      vm_flags;       /* VMA vm_flags */
 148         unsigned long   vm_start;       /* start address of region */
 149         unsigned long   vm_end;         /* region initialised to here */
 150         unsigned long   vm_top;         /* region allocated to here */
 151         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 152         struct file     *vm_file;       /* the backing file or NULL */
 153
 154         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 155         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 156                                                 * this region */
 157 };
 158
 159 /*
 160  * This struct defines a memory VMM memory area. There is one of these
 161  * per VM-area/task.  A VM area is any part of the process virtual memory
 162  * space that has a special rule for the page-fault handlers (ie a shared
 163  * library, the executable area etc).
 164  */
 165 struct vm_area_struct {
 166         struct mm_struct * vm_mm;       /* The address space we belong to. */
 167         unsigned long vm_start;         /* Our start address within vm_mm. */
 168         unsigned long vm_end;           /* The first byte after our end address
 169                                            within vm_mm. */
 170
 171         /* linked list of VM areas per task, sorted by address */
 172         struct vm_area_struct *vm_next, *vm_prev;
 173
 174         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 175         unsigned long vm_flags;         /* Flags, see mm.h. */
 176
 177         struct rb_node vm_rb;
 178
 179         /*
 180          * For areas with an address space and backing store,
 181          * linkage into the address_space->i_mmap prio tree, or
 182          * linkage to the list of like vmas hanging off its node, or
 183          * linkage of vma in the address_space->i_mmap_nonlinear list.
 184          */
 185         union {
 186                 struct {
 187                         struct list_head list;
 188                         void *parent;   /* aligns with prio_tree_node parent */
 189                         struct vm_area_struct *head;
 190                 } vm_set;
 191
 192                 struct raw_prio_tree_node prio_tree_node;
 193         } shared;
 194
 195         /*
 196          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 197          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 198          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 199          * or brk vma (with NULL file) can only be in an anon_vma list.
 200          */
 201         struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 202                                           * page_table_lock */
 203         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 204
 205         /* Function pointers to deal with this struct. */
 206         const struct vm_operations_struct *vm_ops;
 207
 208         /* Information about our backing store: */
 209         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 210                                            units, *not* PAGE_CACHE_SIZE */
 211         struct file * vm_file;          /* File we map to (can be NULL). */
 212         void * vm_private_data;         /* was vm_pte (shared mem) */
 213
 214 #ifndef CONFIG_MMU
 215         struct vm_region *vm_region;    /* NOMMU mapping region */
 216 #endif
 217 #ifdef CONFIG_NUMA
 218         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 219 #endif
 220 };
 221
 222 struct core_thread {
 223         struct task_struct *task;
 224         struct core_thread *next;
 225 };
 226
 227 struct core_state {
 228         atomic_t nr_threads;
 229         struct core_thread dumper;
 230         struct completion startup;
 231 };
 232
 233 enum {
 234         MM_FILEPAGES,
 235         MM_ANONPAGES,
 236         MM_SWAPENTS,
 237         NR_MM_COUNTERS
 238 };
 239
 240 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 241 #define SPLIT_RSS_COUNTING
 242 /* per-thread cached information, */
 243 struct task_rss_stat {
 244         int events;     /* for synchronization threshold */
 245         int count[NR_MM_COUNTERS];
 246 };
 247 #endif /* USE_SPLIT_PTLOCKS */
 248
 249 struct mm_rss_stat {
 250         atomic_long_t count[NR_MM_COUNTERS];
 251 };
 252
 253 struct mm_struct {
 254         struct vm_area_struct * mmap;           /* list of VMAs */
 255         struct rb_root mm_rb;
 256         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 257 #ifdef CONFIG_MMU
 258         unsigned long (*get_unmapped_area) (struct file *filp,
 259                                 unsigned long addr, unsigned long len,
 260                                 unsigned long pgoff, unsigned long flags);
 261         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 262 #endif
 263         unsigned long mmap_base;                /* base of mmap area */
 264         unsigned long task_size;                /* size of task vm space */
 265         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 266         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 267         pgd_t * pgd;
 268         atomic_t mm_users;                      /* How many users with user space? */
 269         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 270         int map_count;                          /* number of VMAs */
 271
 272         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 273         struct rw_semaphore mmap_sem;
 274
 275         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 276                                                  * together off init_mm.mmlist, and are protected
 277                                                  * by mmlist_lock
 278                                                  */
 279
 280
 281         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 282         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 283
 284         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 285         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 286         unsigned long start_code, end_code, start_data, end_data;
 287         unsigned long start_brk, brk, start_stack;
 288         unsigned long arg_start, arg_end, env_start, env_end;
 289
 290         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 291
 292         /*
 293          * Special counters, in some configurations protected by the
 294          * page_table_lock, in other configurations by being atomic.
 295          */
 296         struct mm_rss_stat rss_stat;
 297
 298         struct linux_binfmt *binfmt;
 299
 300         cpumask_var_t cpu_vm_mask_var;
 301
 302         /* Architecture-specific MM context */
 303         mm_context_t context;
 304
 305         /* Swap token stuff */
 306         /*
 307          * Last value of global fault stamp as seen by this process.
 308          * In other words, this value gives an indication of how long
 309          * it has been since this task got the token.
 310          * Look at mm/thrash.c
 311          */
 312         unsigned int faultstamp;
 313         unsigned int token_priority;
 314         unsigned int last_interval;
 315
 316         /* How many tasks sharing this mm are OOM_DISABLE */
 317         atomic_t oom_disable_count;
 318
 319         unsigned long flags; /* Must use atomic bitops to access the bits */
 320
 321         struct core_state *core_state; /* coredumping support */
 322 #ifdef CONFIG_AIO
 323         spinlock_t              ioctx_lock;
 324         struct hlist_head       ioctx_list;
 325 #endif
 326 #ifdef CONFIG_MM_OWNER
 327         /*
 328          * "owner" points to a task that is regarded as the canonical
 329          * user/owner of this mm. All of the following must be true in
 330          * order for it to be changed:
 331          *
 332          * current == mm->owner
 333          * current->mm != mm
 334          * new_owner->mm == mm
 335          * new_owner->alloc_lock is held
 336          */
 337         struct task_struct __rcu *owner;
 338 #endif
 339
 340         /* store ref to file /proc/<pid>/exe symlink points to */
 341         struct file *exe_file;
 342         unsigned long num_exe_file_vmas;
 343 #ifdef CONFIG_MMU_NOTIFIER
 344         struct mmu_notifier_mm *mmu_notifier_mm;
 345 #endif
 346 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 347         pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 348 #endif
 349 #ifdef CONFIG_CPUMASK_OFFSTACK
 350         struct cpumask cpumask_allocation;
 351 #endif
 352 };
 353
 354 static inline void mm_init_cpumask(struct mm_struct *mm)
 355 {
 356 #ifdef CONFIG_CPUMASK_OFFSTACK
 357         mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 358 #endif
 359 }
 360
 361 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 362 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 363 {
 364         return mm->cpu_vm_mask_var;
 365 }
 366
 367 #endif /* _LINUX_MM_TYPES_H */