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                                         /*
  66                                          * Count of ptes mapped in
  67                                          * mms, to show when page is
  68                                          * mapped & limit reverse map
  69                                          * searches.
  70                                          *
  71                                          * Used also for tail pages
  72                                          * refcounting instead of
  73                                          * _count. Tail pages cannot
  74                                          * be mapped and keeping the
  75                                          * tail page _count zero at
  76                                          * all times guarantees
  77                                          * get_page_unless_zero() will
  78                                          * never succeed on tail
  79                                          * pages.
  80                                          */
  81                                         atomic_t _mapcount;
  82
  83                                         struct {
  84                                                 unsigned inuse:16;
  85                                                 unsigned objects:15;
  86                                                 unsigned frozen:1;
  87                                         };
  88                                 };
  89                                 atomic_t _count;                /* Usage count, see below. */
  90                         };
  91                 };
  92         };
  93
  94         /* Third double word block */
  95         union {
  96                 struct list_head lru;   /* Pageout list, eg. active_list
  97                                          * protected by zone->lru_lock !
  98                                          */
  99                 struct {                /* slub per cpu partial pages */
 100                         struct page *next;      /* Next partial slab */
 101 #ifdef CONFIG_64BIT
 102                         int pages;      /* Nr of partial slabs left */
 103                         int pobjects;   /* Approximate # of objects */
 104 #else
 105                         short int pages;
 106                         short int pobjects;
 107 #endif
 108                 };
 109         };
 110
 111         /* Remainder is not double word aligned */
 112         union {
 113                 unsigned long private;          /* Mapping-private opaque data:
 114                                                  * usually used for buffer_heads
 115                                                  * if PagePrivate set; used for
 116                                                  * swp_entry_t if PageSwapCache;
 117                                                  * indicates order in the buddy
 118                                                  * system if PG_buddy is set.
 119                                                  */
 120 #if USE_SPLIT_PTLOCKS
 121                 spinlock_t ptl;
 122 #endif
 123                 struct kmem_cache *slab;        /* SLUB: Pointer to slab */
 124                 struct page *first_page;        /* Compound tail pages */
 125         };
 126
 127         /*
 128          * On machines where all RAM is mapped into kernel address space,
 129          * we can simply calculate the virtual address. On machines with
 130          * highmem some memory is mapped into kernel virtual memory
 131          * dynamically, so we need a place to store that address.
 132          * Note that this field could be 16 bits on x86 ... ;)
 133          *
 134          * Architectures with slow multiplication can define
 135          * WANT_PAGE_VIRTUAL in asm/page.h
 136          */
 137 #if defined(WANT_PAGE_VIRTUAL)
 138         void *virtual;                  /* Kernel virtual address (NULL if
 139                                            not kmapped, ie. highmem) */
 140 #endif /* WANT_PAGE_VIRTUAL */
 141 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 142         unsigned long debug_flags;      /* Use atomic bitops on this */
 143 #endif
 144
 145 #ifdef CONFIG_KMEMCHECK
 146         /*
 147          * kmemcheck wants to track the status of each byte in a page; this
 148          * is a pointer to such a status block. NULL if not tracked.
 149          */
 150         void *shadow;
 151 #endif
 152 }
 153 /*
 154  * If another subsystem starts using the double word pairing for atomic
 155  * operations on struct page then it must change the #if to ensure
 156  * proper alignment of the page struct.
 157  */
 158 #if defined(CONFIG_SLUB) && defined(CONFIG_CMPXCHG_LOCAL)
 159         __attribute__((__aligned__(2*sizeof(unsigned long))))
 160 #endif
 161 ;
 162
 163 struct page_frag {
 164         struct page *page;
 165 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
 166         __u32 offset;
 167         __u32 size;
 168 #else
 169         __u16 offset;
 170         __u16 size;
 171 #endif
 172 };
 173
 174 typedef unsigned long __nocast vm_flags_t;
 175
 176 /*
 177  * A region containing a mapping of a non-memory backed file under NOMMU
 178  * conditions.  These are held in a global tree and are pinned by the VMAs that
 179  * map parts of them.
 180  */
 181 struct vm_region {
 182         struct rb_node  vm_rb;          /* link in global region tree */
 183         vm_flags_t      vm_flags;       /* VMA vm_flags */
 184         unsigned long   vm_start;       /* start address of region */
 185         unsigned long   vm_end;         /* region initialised to here */
 186         unsigned long   vm_top;         /* region allocated to here */
 187         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 188         struct file     *vm_file;       /* the backing file or NULL */
 189
 190         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 191         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 192                                                 * this region */
 193 };
 194
 195 /*
 196  * This struct defines a memory VMM memory area. There is one of these
 197  * per VM-area/task.  A VM area is any part of the process virtual memory
 198  * space that has a special rule for the page-fault handlers (ie a shared
 199  * library, the executable area etc).
 200  */
 201 struct vm_area_struct {
 202         struct mm_struct * vm_mm;       /* The address space we belong to. */
 203         unsigned long vm_start;         /* Our start address within vm_mm. */
 204         unsigned long vm_end;           /* The first byte after our end address
 205                                            within vm_mm. */
 206
 207         /* linked list of VM areas per task, sorted by address */
 208         struct vm_area_struct *vm_next, *vm_prev;
 209
 210         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 211         unsigned long vm_flags;         /* Flags, see mm.h. */
 212
 213         struct rb_node vm_rb;
 214
 215         /*
 216          * For areas with an address space and backing store,
 217          * linkage into the address_space->i_mmap prio tree, or
 218          * linkage to the list of like vmas hanging off its node, or
 219          * linkage of vma in the address_space->i_mmap_nonlinear list.
 220          */
 221         union {
 222                 struct {
 223                         struct list_head list;
 224                         void *parent;   /* aligns with prio_tree_node parent */
 225                         struct vm_area_struct *head;
 226                 } vm_set;
 227
 228                 struct raw_prio_tree_node prio_tree_node;
 229         } shared;
 230
 231         /*
 232          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 233          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 234          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 235          * or brk vma (with NULL file) can only be in an anon_vma list.
 236          */
 237         struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 238                                           * page_table_lock */
 239         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 240
 241         /* Function pointers to deal with this struct. */
 242         const struct vm_operations_struct *vm_ops;
 243
 244         /* Information about our backing store: */
 245         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 246                                            units, *not* PAGE_CACHE_SIZE */
 247         struct file * vm_file;          /* File we map to (can be NULL). */
 248         void * vm_private_data;         /* was vm_pte (shared mem) */
 249
 250 #ifndef CONFIG_MMU
 251         struct vm_region *vm_region;    /* NOMMU mapping region */
 252 #endif
 253 #ifdef CONFIG_NUMA
 254         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 255 #endif
 256 };
 257
 258 struct core_thread {
 259         struct task_struct *task;
 260         struct core_thread *next;
 261 };
 262
 263 struct core_state {
 264         atomic_t nr_threads;
 265         struct core_thread dumper;
 266         struct completion startup;
 267 };
 268
 269 enum {
 270         MM_FILEPAGES,
 271         MM_ANONPAGES,
 272         MM_SWAPENTS,
 273         NR_MM_COUNTERS
 274 };
 275
 276 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 277 #define SPLIT_RSS_COUNTING
 278 /* per-thread cached information, */
 279 struct task_rss_stat {
 280         int events;     /* for synchronization threshold */
 281         int count[NR_MM_COUNTERS];
 282 };
 283 #endif /* USE_SPLIT_PTLOCKS */
 284
 285 struct mm_rss_stat {
 286         atomic_long_t count[NR_MM_COUNTERS];
 287 };
 288
 289 struct mm_struct {
 290         struct vm_area_struct * mmap;           /* list of VMAs */
 291         struct rb_root mm_rb;
 292         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 293 #ifdef CONFIG_MMU
 294         unsigned long (*get_unmapped_area) (struct file *filp,
 295                                 unsigned long addr, unsigned long len,
 296                                 unsigned long pgoff, unsigned long flags);
 297         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 298 #endif
 299         unsigned long mmap_base;                /* base of mmap area */
 300         unsigned long task_size;                /* size of task vm space */
 301         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 302         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 303         pgd_t * pgd;
 304         atomic_t mm_users;                      /* How many users with user space? */
 305         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 306         int map_count;                          /* number of VMAs */
 307
 308         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 309         struct rw_semaphore mmap_sem;
 310
 311         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 312                                                  * together off init_mm.mmlist, and are protected
 313                                                  * by mmlist_lock
 314                                                  */
 315
 316
 317         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 318         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 319
 320         unsigned long total_vm;         /* Total pages mapped */
 321         unsigned long locked_vm;        /* Pages that have PG_mlocked set */
 322         unsigned long pinned_vm;        /* Refcount permanently increased */
 323         unsigned long shared_vm;        /* Shared pages (files) */
 324         unsigned long exec_vm;          /* VM_EXEC & ~VM_WRITE */
 325         unsigned long stack_vm;         /* VM_GROWSUP/DOWN */
 326         unsigned long reserved_vm;      /* VM_RESERVED|VM_IO pages */
 327         unsigned long def_flags;
 328         unsigned long nr_ptes;          /* Page table pages */
 329         unsigned long start_code, end_code, start_data, end_data;
 330         unsigned long start_brk, brk, start_stack;
 331         unsigned long arg_start, arg_end, env_start, env_end;
 332
 333         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 334
 335         /*
 336          * Special counters, in some configurations protected by the
 337          * page_table_lock, in other configurations by being atomic.
 338          */
 339         struct mm_rss_stat rss_stat;
 340
 341         struct linux_binfmt *binfmt;
 342
 343         cpumask_var_t cpu_vm_mask_var;
 344
 345         /* Architecture-specific MM context */
 346         mm_context_t context;
 347
 348         /* Swap token stuff */
 349         /*
 350          * Last value of global fault stamp as seen by this process.
 351          * In other words, this value gives an indication of how long
 352          * it has been since this task got the token.
 353          * Look at mm/thrash.c
 354          */
 355         unsigned int faultstamp;
 356         unsigned int token_priority;
 357         unsigned int last_interval;
 358
 359         unsigned long flags; /* Must use atomic bitops to access the bits */
 360
 361         struct core_state *core_state; /* coredumping support */
 362 #ifdef CONFIG_AIO
 363         spinlock_t              ioctx_lock;
 364         struct hlist_head       ioctx_list;
 365 #endif
 366 #ifdef CONFIG_MM_OWNER
 367         /*
 368          * "owner" points to a task that is regarded as the canonical
 369          * user/owner of this mm. All of the following must be true in
 370          * order for it to be changed:
 371          *
 372          * current == mm->owner
 373          * current->mm != mm
 374          * new_owner->mm == mm
 375          * new_owner->alloc_lock is held
 376          */
 377         struct task_struct __rcu *owner;
 378 #endif
 379
 380         /* store ref to file /proc/<pid>/exe symlink points to */
 381         struct file *exe_file;
 382         unsigned long num_exe_file_vmas;
 383 #ifdef CONFIG_MMU_NOTIFIER
 384         struct mmu_notifier_mm *mmu_notifier_mm;
 385 #endif
 386 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 387         pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 388 #endif
 389 #ifdef CONFIG_CPUMASK_OFFSTACK
 390         struct cpumask cpumask_allocation;
 391 #endif
 392 };
 393
 394 static inline void mm_init_cpumask(struct mm_struct *mm)
 395 {
 396 #ifdef CONFIG_CPUMASK_OFFSTACK
 397         mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 398 #endif
 399 }
 400
 401 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 402 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 403 {
 404         return mm->cpu_vm_mask_var;
 405 }
 406
 407 #endif /* _LINUX_MM_TYPES_H */