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