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 <asm/page.h>
  15 #include <asm/mmu.h>
  16
  17 #ifndef AT_VECTOR_SIZE_ARCH
  18 #define AT_VECTOR_SIZE_ARCH 0
  19 #endif
  20 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
  21
  22 struct address_space;
  23
  24 #define USE_SPLIT_PTLOCKS       (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
  25
  26 #if USE_SPLIT_PTLOCKS
  27 typedef atomic_long_t mm_counter_t;
  28 #else  /* !USE_SPLIT_PTLOCKS */
  29 typedef unsigned long mm_counter_t;
  30 #endif /* !USE_SPLIT_PTLOCKS */
  31
  32 /*
  33  * Each physical page in the system has a struct page associated with
  34  * it to keep track of whatever it is we are using the page for at the
  35  * moment. Note that we have no way to track which tasks are using
  36  * a page, though if it is a pagecache page, rmap structures can tell us
  37  * who is mapping it.
  38  */
  39 struct page {
  40         unsigned long flags;            /* Atomic flags, some possibly
  41                                          * updated asynchronously */
  42         atomic_t _count;                /* Usage count, see below. */
  43         union {
  44                 atomic_t _mapcount;     /* Count of ptes mapped in mms,
  45                                          * to show when page is mapped
  46                                          * & limit reverse map searches.
  47                                          */
  48                 struct {                /* SLUB */
  49                         u16 inuse;
  50                         u16 objects;
  51                 };
  52         };
  53         union {
  54             struct {
  55                 unsigned long private;          /* Mapping-private opaque data:
  56                                                  * usually used for buffer_heads
  57                                                  * if PagePrivate set; used for
  58                                                  * swp_entry_t if PageSwapCache;
  59                                                  * indicates order in the buddy
  60                                                  * system if PG_buddy is set.
  61                                                  */
  62                 struct address_space *mapping;  /* If low bit clear, points to
  63                                                  * inode address_space, or NULL.
  64                                                  * If page mapped as anonymous
  65                                                  * memory, low bit is set, and
  66                                                  * it points to anon_vma object:
  67                                                  * see PAGE_MAPPING_ANON below.
  68                                                  */
  69             };
  70 #if USE_SPLIT_PTLOCKS
  71 #ifndef CONFIG_PREEMPT_RT
  72             spinlock_t ptl;
  73 #else
  74             spinlock_t *ptl;
  75 #endif
  76 #endif
  77             struct kmem_cache *slab;    /* SLUB: Pointer to slab */
  78             struct page *first_page;    /* Compound tail pages */
  79         };
  80         union {
  81                 pgoff_t index;          /* Our offset within mapping. */
  82                 void *freelist;         /* SLUB: freelist req. slab lock */
  83         };
  84         struct list_head lru;           /* Pageout list, eg. active_list
  85                                          * protected by zone->lru_lock !
  86                                          */
  87         /*
  88          * On machines where all RAM is mapped into kernel address space,
  89          * we can simply calculate the virtual address. On machines with
  90          * highmem some memory is mapped into kernel virtual memory
  91          * dynamically, so we need a place to store that address.
  92          * Note that this field could be 16 bits on x86 ... ;)
  93          *
  94          * Architectures with slow multiplication can define
  95          * WANT_PAGE_VIRTUAL in asm/page.h
  96          */
  97 #if defined(WANT_PAGE_VIRTUAL)
  98         void *virtual;                  /* Kernel virtual address (NULL if
  99                                            not kmapped, ie. highmem) */
 100 #endif /* WANT_PAGE_VIRTUAL */
 101
 102 #ifdef CONFIG_KMEMCHECK
 103         /*
 104          * kmemcheck wants to track the status of each byte in a page; this
 105          * is a pointer to such a status block. NULL if not tracked.
 106          */
 107         void *shadow;
 108 #endif
 109 };
 110
 111 /*
 112  * A region containing a mapping of a non-memory backed file under NOMMU
 113  * conditions.  These are held in a global tree and are pinned by the VMAs that
 114  * map parts of them.
 115  */
 116 struct vm_region {
 117         struct rb_node  vm_rb;          /* link in global region tree */
 118         unsigned long   vm_flags;       /* VMA vm_flags */
 119         unsigned long   vm_start;       /* start address of region */
 120         unsigned long   vm_end;         /* region initialised to here */
 121         unsigned long   vm_top;         /* region allocated to here */
 122         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 123         struct file     *vm_file;       /* the backing file or NULL */
 124
 125         atomic_t        vm_usage;       /* region usage count */
 126 };
 127
 128 /*
 129  * This struct defines a memory VMM memory area. There is one of these
 130  * per VM-area/task.  A VM area is any part of the process virtual memory
 131  * space that has a special rule for the page-fault handlers (ie a shared
 132  * library, the executable area etc).
 133  */
 134 struct vm_area_struct {
 135         struct mm_struct * vm_mm;       /* The address space we belong to. */
 136         unsigned long vm_start;         /* Our start address within vm_mm. */
 137         unsigned long vm_end;           /* The first byte after our end address
 138                                            within vm_mm. */
 139
 140         /* linked list of VM areas per task, sorted by address */
 141         struct vm_area_struct *vm_next;
 142
 143         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 144         unsigned long vm_flags;         /* Flags, see mm.h. */
 145
 146         struct rb_node vm_rb;
 147
 148         /*
 149          * For areas with an address space and backing store,
 150          * linkage into the address_space->i_mmap prio tree, or
 151          * linkage to the list of like vmas hanging off its node, or
 152          * linkage of vma in the address_space->i_mmap_nonlinear list.
 153          */
 154         union {
 155                 struct {
 156                         struct list_head list;
 157                         void *parent;   /* aligns with prio_tree_node parent */
 158                         struct vm_area_struct *head;
 159                 } vm_set;
 160
 161                 struct raw_prio_tree_node prio_tree_node;
 162         } shared;
 163
 164         /*
 165          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 166          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 167          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 168          * or brk vma (with NULL file) can only be in an anon_vma list.
 169          */
 170         struct list_head anon_vma_node; /* Serialized by anon_vma->lock */
 171         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 172
 173         /* Function pointers to deal with this struct. */
 174         struct vm_operations_struct * vm_ops;
 175
 176         /* Information about our backing store: */
 177         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 178                                            units, *not* PAGE_CACHE_SIZE */
 179         struct file * vm_file;          /* File we map to (can be NULL). */
 180         void * vm_private_data;         /* was vm_pte (shared mem) */
 181         unsigned long vm_truncate_count;/* truncate_count or restart_addr */
 182
 183 #ifndef CONFIG_MMU
 184         struct vm_region *vm_region;    /* NOMMU mapping region */
 185 #endif
 186 #ifdef CONFIG_NUMA
 187         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 188 #endif
 189 };
 190
 191 struct core_thread {
 192         struct task_struct *task;
 193         struct core_thread *next;
 194 };
 195
 196 struct core_state {
 197         atomic_t nr_threads;
 198         struct core_thread dumper;
 199         struct completion startup;
 200 };
 201
 202 struct mm_struct {
 203         struct vm_area_struct * mmap;           /* list of VMAs */
 204         struct rb_root mm_rb;
 205         struct vm_area_struct * mmap_cache;     /* last find_vma result */
 206         unsigned long (*get_unmapped_area) (struct file *filp,
 207                                 unsigned long addr, unsigned long len,
 208                                 unsigned long pgoff, unsigned long flags);
 209         void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 210         unsigned long mmap_base;                /* base of mmap area */
 211         unsigned long task_size;                /* size of task vm space */
 212         unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 213         unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 214         pgd_t * pgd;
 215         atomic_t mm_users;                      /* How many users with user space? */
 216         atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 217         int map_count;                          /* number of VMAs */
 218         struct rw_semaphore mmap_sem;
 219         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 220
 221         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 222                                                  * together off init_mm.mmlist, and are protected
 223                                                  * by mmlist_lock
 224                                                  */
 225
 226         /* Special counters, in some configurations protected by the
 227          * page_table_lock, in other configurations by being atomic.
 228          */
 229         mm_counter_t _file_rss;
 230         mm_counter_t _anon_rss;
 231
 232         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 233         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 234
 235         unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 236         unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 237         unsigned long start_code, end_code, start_data, end_data;
 238         unsigned long start_brk, brk, start_stack;
 239         unsigned long arg_start, arg_end, env_start, env_end;
 240
 241         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 242
 243         cpumask_t cpu_vm_mask;
 244
 245         /* Architecture-specific MM context */
 246         mm_context_t context;
 247
 248         /* realtime bits */
 249         struct list_head        delayed_drop;
 250
 251         /* Swap token stuff */
 252         /*
 253          * Last value of global fault stamp as seen by this process.
 254          * In other words, this value gives an indication of how long
 255          * it has been since this task got the token.
 256          * Look at mm/thrash.c
 257          */
 258         unsigned int faultstamp;
 259         unsigned int token_priority;
 260         unsigned int last_interval;
 261
 262         unsigned long flags; /* Must use atomic bitops to access the bits */
 263
 264         struct core_state *core_state; /* coredumping support */
 265
 266         /* aio bits */
 267         spinlock_t              ioctx_lock;
 268         struct hlist_head       ioctx_list;
 269
 270 #ifdef CONFIG_MM_OWNER
 271         /*
 272          * "owner" points to a task that is regarded as the canonical
 273          * user/owner of this mm. All of the following must be true in
 274          * order for it to be changed:
 275          *
 276          * current == mm->owner
 277          * current->mm != mm
 278          * new_owner->mm == mm
 279          * new_owner->alloc_lock is held
 280          */
 281         struct task_struct *owner;
 282 #endif
 283
 284 #ifdef CONFIG_PROC_FS
 285         /* store ref to file /proc/<pid>/exe symlink points to */
 286         struct file *exe_file;
 287         unsigned long num_exe_file_vmas;
 288 #endif
 289 #ifdef CONFIG_MMU_NOTIFIER
 290         struct mmu_notifier_mm *mmu_notifier_mm;
 291 #endif
 292 };
 293
 294 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 295 #define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
 296
 297 #endif /* _LINUX_MM_TYPES_H */