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 struct page {
  35         unsigned long flags;            /* Atomic flags, some possibly
  36                                          * updated asynchronously */
  37         atomic_t _count;                /* Usage count, see below. */
  38         union {
  39                 atomic_t _mapcount;     /* Count of ptes mapped in mms,
  40                                          * to show when page is mapped
  41                                          * & limit reverse map searches.
  42                                          */
  43                 struct {                /* SLUB */
  44                         u16 inuse;
  45                         u16 objects;
  46                 };
  47         };
  48         union {
  49             struct {
  50                 unsigned long private;          /* Mapping-private opaque data:
  51                                                  * usually used for buffer_heads
  52                                                  * if PagePrivate set; used for
  53                                                  * swp_entry_t if PageSwapCache;
  54                                                  * indicates order in the buddy
  55                                                  * system if PG_buddy is set.
  56                                                  */
  57                 struct address_space *mapping;  /* If low bit clear, points to
  58                                                  * inode address_space, or NULL.
  59                                                  * If page mapped as anonymous
  60                                                  * memory, low bit is set, and
  61                                                  * it points to anon_vma object:
  62                                                  * see PAGE_MAPPING_ANON below.
  63                                                  */
  64             };
  65 #if USE_SPLIT_PTLOCKS
  66             spinlock_t ptl;
  67 #endif
  68             struct kmem_cache *slab;    /* SLUB: Pointer to slab */
  69             struct page *first_page;    /* Compound tail pages */
  70         };
  71         union {
  72                 pgoff_t index;          /* Our offset within mapping. */
  73                 void *freelist;         /* SLUB: freelist req. slab lock */
  74         };
  75         struct list_head lru;           /* Pageout list, eg. active_list
  76                                          * protected by zone->lru_lock !
  77                                          */
  78         /*
  79          * On machines where all RAM is mapped into kernel address space,
  80          * we can simply calculate the virtual address. On machines with
  81          * highmem some memory is mapped into kernel virtual memory
  82          * dynamically, so we need a place to store that address.
  83          * Note that this field could be 16 bits on x86 ... ;)
  84          *
  85          * Architectures with slow multiplication can define
  86          * WANT_PAGE_VIRTUAL in asm/page.h
  87          */
  88 #if defined(WANT_PAGE_VIRTUAL)
  89         void *virtual;                  /* Kernel virtual address (NULL if
  90                                            not kmapped, ie. highmem) */
  91 #endif /* WANT_PAGE_VIRTUAL */
  92 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
  93         unsigned long debug_flags;      /* Use atomic bitops on this */
  94 #endif
  95
  96 #ifdef CONFIG_KMEMCHECK
  97         /*
  98          * kmemcheck wants to track the status of each byte in a page; this
  99          * is a pointer to such a status block. NULL if not tracked.
 100          */
 101         void *shadow;
 102 #endif
 103 };
 104
 105 /*
 106  * A region containing a mapping of a non-memory backed file under NOMMU
 107  * conditions.  These are held in a global tree and are pinned by the VMAs that
 108  * map parts of them.
 109  */
 110 struct vm_region {
 111         struct rb_node  vm_rb;          /* link in global region tree */
 112         unsigned long   vm_flags;       /* VMA vm_flags */
 113         unsigned long   vm_start;       /* start address of region */
 114         unsigned long   vm_end;         /* region initialised to here */
 115         unsigned long   vm_top;         /* region allocated to here */
 116         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 117         struct file     *vm_file;       /* the backing file or NULL */
 118
 119         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 120         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 121                                                 * this region */
 122 };
 123
 124 /*
 125  * This struct defines a memory VMM memory area. There is one of these
 126  * per VM-area/task.  A VM area is any part of the process virtual memory
 127  * space that has a special rule for the page-fault handlers (ie a shared
 128  * library, the executable area etc).
 129  */
 130 struct vm_area_struct {
 131         struct mm_struct * vm_mm;       /* The address space we belong to. */
 132         unsigned long vm_start;         /* Our start address within vm_mm. */
 133         unsigned long vm_end;           /* The first byte after our end address
 134                                            within vm_mm. */
 135
 136         /* linked list of VM areas per task, sorted by address */
 137         struct vm_area_struct *vm_next, *vm_prev;
 138
 139         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 140         unsigned long vm_flags;         /* Flags, see mm.h. */
 141
 142         struct rb_node vm_rb;
 143
 144         /*
 145          * For areas with an address space and backing store,
 146          * linkage into the address_space->i_mmap prio tree, or
 147          * linkage to the list of like vmas hanging off its node, or
 148          * linkage of vma in the address_space->i_mmap_nonlinear list.
 149          */
 150         union {
 151                 struct {
 152                         struct list_head list;
 153                         void *parent;   /* aligns with prio_tree_node parent */
 154                         struct vm_area_struct *head;
 155                 } vm_set;
 156
 157                 struct raw_prio_tree_node prio_tree_node;
 158         } shared;
 159
 160         /*
 161          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 162          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 163          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 164          * or brk vma (with NULL file) can only be in an anon_vma list.
 165          */
 166         struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 167                                           * page_table_lock */
 168         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 169
 170         /* Function pointers to deal with this struct. */
 171         const struct vm_operations_struct *vm_ops;
 172
 173         /* Information about our backing store: */
 174         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 175                                            units, *not* PAGE_CACHE_SIZE */
 176         struct file * vm_file;          /* File we map to (can be NULL). */
 177         void * vm_private_data;         /* was vm_pte (shared mem) */
 178         unsigned long vm_truncate_count;/* truncate_count or restart_addr */
 179
 180 #ifndef CONFIG_MMU
 181         struct vm_region *vm_region;    /* NOMMU mapping region */
 182 #endif
 183 #ifdef CONFIG_NUMA
 184         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 185 #endif
 186 };
 187
 188 struct core_thread {
 189         struct task_struct *task;
 190         struct core_thread *next;
 191 };
 192
 193 struct core_state {
 194         atomic_t nr_threads;
 195         struct core_thread dumper;
 196         struct completion startup;
 197 };
 198
 199 enum {
 200         MM_FILEPAGES,
 201         MM_ANONPAGES,
 202         MM_SWAPENTS,
 203         NR_MM_COUNTERS
 204 };
 205
 206 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 207 #define SPLIT_RSS_COUNTING
 208 struct mm_rss_stat {
 209         atomic_long_t count[NR_MM_COUNTERS];
 210 };
 211 /* per-thread cached information, */
 212 struct task_rss_stat {
 213         int events;     /* for synchronization threshold */
 214         int count[NR_MM_COUNTERS];
 215 };
 216 #else  /* !USE_SPLIT_PTLOCKS */
 217 struct mm_rss_stat {
 218         unsigned long count[NR_MM_COUNTERS];
 219 };
 220 #endif /* !USE_SPLIT_PTLOCKS */
 221
 222 struct mm_struct {
 223         struct vm_area_struct * mmap;           /* list of VMAs */
 224         struct rb_root mm_rb;
 225         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 226 #ifdef CONFIG_MMU
 227         unsigned long (*get_unmapped_area) (struct file *filp,
 228                                 unsigned long addr, unsigned long len,
 229                                 unsigned long pgoff, unsigned long flags);
 230         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 231 #endif
 232         unsigned long mmap_base;                /* base of mmap area */
 233         unsigned long task_size;                /* size of task vm space */
 234         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 235         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 236         pgd_t * pgd;
 237         atomic_t mm_users;                      /* How many users with user space? */
 238         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 239         int map_count;                          /* number of VMAs */
 240
 241         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 242         struct rw_semaphore mmap_sem;
 243
 244         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 245                                                  * together off init_mm.mmlist, and are protected
 246                                                  * by mmlist_lock
 247                                                  */
 248
 249
 250         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 251         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 252
 253         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 254         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 255         unsigned long start_code, end_code, start_data, end_data;
 256         unsigned long start_brk, brk, start_stack;
 257         unsigned long arg_start, arg_end, env_start, env_end;
 258
 259         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 260
 261         /*
 262          * Special counters, in some configurations protected by the
 263          * page_table_lock, in other configurations by being atomic.
 264          */
 265         struct mm_rss_stat rss_stat;
 266
 267         struct linux_binfmt *binfmt;
 268
 269         cpumask_t cpu_vm_mask;
 270
 271         /* Architecture-specific MM context */
 272         mm_context_t context;
 273
 274         /* Swap token stuff */
 275         /*
 276          * Last value of global fault stamp as seen by this process.
 277          * In other words, this value gives an indication of how long
 278          * it has been since this task got the token.
 279          * Look at mm/thrash.c
 280          */
 281         unsigned int faultstamp;
 282         unsigned int token_priority;
 283         unsigned int last_interval;
 284
 285         /* How many tasks sharing this mm are OOM_DISABLE */
 286         atomic_t oom_disable_count;
 287
 288         unsigned long flags; /* Must use atomic bitops to access the bits */
 289
 290         struct core_state *core_state; /* coredumping support */
 291 #ifdef CONFIG_AIO
 292         spinlock_t              ioctx_lock;
 293         struct hlist_head       ioctx_list;
 294 #endif
 295 #ifdef CONFIG_MM_OWNER
 296         /*
 297          * "owner" points to a task that is regarded as the canonical
 298          * user/owner of this mm. All of the following must be true in
 299          * order for it to be changed:
 300          *
 301          * current == mm->owner
 302          * current->mm != mm
 303          * new_owner->mm == mm
 304          * new_owner->alloc_lock is held
 305          */
 306         struct task_struct __rcu *owner;
 307 #endif
 308
 309 #ifdef CONFIG_PROC_FS
 310         /* store ref to file /proc/<pid>/exe symlink points to */
 311         struct file *exe_file;
 312         unsigned long num_exe_file_vmas;
 313 #endif
 314 #ifdef CONFIG_MMU_NOTIFIER
 315         struct mmu_notifier_mm *mmu_notifier_mm;
 316 #endif
 317 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 318         pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 319 #endif
 320 };
 321
 322 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 323 #define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
 324
 325 #endif /* _LINUX_MM_TYPES_H */