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 typedef unsigned long __nocast vm_flags_t;
 151
 152 /*
 153  * A region containing a mapping of a non-memory backed file under NOMMU
 154  * conditions.  These are held in a global tree and are pinned by the VMAs that
 155  * map parts of them.
 156  */
 157 struct vm_region {
 158         struct rb_node  vm_rb;          /* link in global region tree */
 159         vm_flags_t      vm_flags;       /* VMA vm_flags */
 160         unsigned long   vm_start;       /* start address of region */
 161         unsigned long   vm_end;         /* region initialised to here */
 162         unsigned long   vm_top;         /* region allocated to here */
 163         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 164         struct file     *vm_file;       /* the backing file or NULL */
 165
 166         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 167         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 168                                                 * this region */
 169 };
 170
 171 /*
 172  * This struct defines a memory VMM memory area. There is one of these
 173  * per VM-area/task.  A VM area is any part of the process virtual memory
 174  * space that has a special rule for the page-fault handlers (ie a shared
 175  * library, the executable area etc).
 176  */
 177 struct vm_area_struct {
 178         struct mm_struct * vm_mm;       /* The address space we belong to. */
 179         unsigned long vm_start;         /* Our start address within vm_mm. */
 180         unsigned long vm_end;           /* The first byte after our end address
 181                                            within vm_mm. */
 182
 183         /* linked list of VM areas per task, sorted by address */
 184         struct vm_area_struct *vm_next, *vm_prev;
 185
 186         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 187         unsigned long vm_flags;         /* Flags, see mm.h. */
 188
 189         struct rb_node vm_rb;
 190
 191         /*
 192          * For areas with an address space and backing store,
 193          * linkage into the address_space->i_mmap prio tree, or
 194          * linkage to the list of like vmas hanging off its node, or
 195          * linkage of vma in the address_space->i_mmap_nonlinear list.
 196          */
 197         union {
 198                 struct {
 199                         struct list_head list;
 200                         void *parent;   /* aligns with prio_tree_node parent */
 201                         struct vm_area_struct *head;
 202                 } vm_set;
 203
 204                 struct raw_prio_tree_node prio_tree_node;
 205         } shared;
 206
 207         /*
 208          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 209          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 210          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 211          * or brk vma (with NULL file) can only be in an anon_vma list.
 212          */
 213         struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 214                                           * page_table_lock */
 215         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 216
 217         /* Function pointers to deal with this struct. */
 218         const struct vm_operations_struct *vm_ops;
 219
 220         /* Information about our backing store: */
 221         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 222                                            units, *not* PAGE_CACHE_SIZE */
 223         struct file * vm_file;          /* File we map to (can be NULL). */
 224         void * vm_private_data;         /* was vm_pte (shared mem) */
 225
 226 #ifndef CONFIG_MMU
 227         struct vm_region *vm_region;    /* NOMMU mapping region */
 228 #endif
 229 #ifdef CONFIG_NUMA
 230         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 231 #endif
 232 };
 233
 234 struct core_thread {
 235         struct task_struct *task;
 236         struct core_thread *next;
 237 };
 238
 239 struct core_state {
 240         atomic_t nr_threads;
 241         struct core_thread dumper;
 242         struct completion startup;
 243 };
 244
 245 enum {
 246         MM_FILEPAGES,
 247         MM_ANONPAGES,
 248         MM_SWAPENTS,
 249         NR_MM_COUNTERS
 250 };
 251
 252 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 253 #define SPLIT_RSS_COUNTING
 254 /* per-thread cached information, */
 255 struct task_rss_stat {
 256         int events;     /* for synchronization threshold */
 257         int count[NR_MM_COUNTERS];
 258 };
 259 #endif /* USE_SPLIT_PTLOCKS */
 260
 261 struct mm_rss_stat {
 262         atomic_long_t count[NR_MM_COUNTERS];
 263 };
 264
 265 struct mm_struct {
 266         struct vm_area_struct * mmap;           /* list of VMAs */
 267         struct rb_root mm_rb;
 268         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 269 #ifdef CONFIG_MMU
 270         unsigned long (*get_unmapped_area) (struct file *filp,
 271                                 unsigned long addr, unsigned long len,
 272                                 unsigned long pgoff, unsigned long flags);
 273         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 274 #endif
 275         unsigned long mmap_base;                /* base of mmap area */
 276         unsigned long task_size;                /* size of task vm space */
 277         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 278         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 279         pgd_t * pgd;
 280         atomic_t mm_users;                      /* How many users with user space? */
 281         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 282         int map_count;                          /* number of VMAs */
 283
 284         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 285         struct rw_semaphore mmap_sem;
 286
 287         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 288                                                  * together off init_mm.mmlist, and are protected
 289                                                  * by mmlist_lock
 290                                                  */
 291
 292
 293         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 294         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 295
 296         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 297         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 298         unsigned long start_code, end_code, start_data, end_data;
 299         unsigned long start_brk, brk, start_stack;
 300         unsigned long arg_start, arg_end, env_start, env_end;
 301
 302         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 303
 304         /*
 305          * Special counters, in some configurations protected by the
 306          * page_table_lock, in other configurations by being atomic.
 307          */
 308         struct mm_rss_stat rss_stat;
 309
 310         struct linux_binfmt *binfmt;
 311
 312         cpumask_var_t cpu_vm_mask_var;
 313
 314         /* Architecture-specific MM context */
 315         mm_context_t context;
 316
 317         /* Swap token stuff */
 318         /*
 319          * Last value of global fault stamp as seen by this process.
 320          * In other words, this value gives an indication of how long
 321          * it has been since this task got the token.
 322          * Look at mm/thrash.c
 323          */
 324         unsigned int faultstamp;
 325         unsigned int token_priority;
 326         unsigned int last_interval;
 327
 328         /* How many tasks sharing this mm are OOM_DISABLE */
 329         atomic_t oom_disable_count;
 330
 331         unsigned long flags; /* Must use atomic bitops to access the bits */
 332
 333         struct core_state *core_state; /* coredumping support */
 334 #ifdef CONFIG_AIO
 335         spinlock_t              ioctx_lock;
 336         struct hlist_head       ioctx_list;
 337 #endif
 338 #ifdef CONFIG_MM_OWNER
 339         /*
 340          * "owner" points to a task that is regarded as the canonical
 341          * user/owner of this mm. All of the following must be true in
 342          * order for it to be changed:
 343          *
 344          * current == mm->owner
 345          * current->mm != mm
 346          * new_owner->mm == mm
 347          * new_owner->alloc_lock is held
 348          */
 349         struct task_struct __rcu *owner;
 350 #endif
 351
 352         /* store ref to file /proc/<pid>/exe symlink points to */
 353         struct file *exe_file;
 354         unsigned long num_exe_file_vmas;
 355 #ifdef CONFIG_MMU_NOTIFIER
 356         struct mmu_notifier_mm *mmu_notifier_mm;
 357 #endif
 358 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 359         pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 360 #endif
 361 #ifdef CONFIG_CPUMASK_OFFSTACK
 362         struct cpumask cpumask_allocation;
 363 #endif
 364 };
 365
 366 static inline void mm_init_cpumask(struct mm_struct *mm)
 367 {
 368 #ifdef CONFIG_CPUMASK_OFFSTACK
 369         mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 370 #endif
 371 }
 372
 373 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 374 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 375 {
 376         return mm->cpu_vm_mask_var;
 377 }
 378
 379 #endif /* _LINUX_MM_TYPES_H */