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