linux/include/linux/mm_types.h
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   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
  23struct 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 */
  40struct 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        struct list_head lru;           /* Pageout list, eg. active_list
  83                                         * protected by zone->lru_lock !
  84                                         */
  85
  86        /* Remainder is not double word aligned */
  87        union {
  88                unsigned long private;          /* Mapping-private opaque data:
  89                                                 * usually used for buffer_heads
  90                                                 * if PagePrivate set; used for
  91                                                 * swp_entry_t if PageSwapCache;
  92                                                 * indicates order in the buddy
  93                                                 * system if PG_buddy is set.
  94                                                 */
  95#if USE_SPLIT_PTLOCKS
  96                spinlock_t ptl;
  97#endif
  98                struct kmem_cache *slab;        /* SLUB: Pointer to slab */
  99                struct page *first_page;        /* Compound tail pages */
 100        };
 101
 102        /*
 103         * On machines where all RAM is mapped into kernel address space,
 104         * we can simply calculate the virtual address. On machines with
 105         * highmem some memory is mapped into kernel virtual memory
 106         * dynamically, so we need a place to store that address.
 107         * Note that this field could be 16 bits on x86 ... ;)
 108         *
 109         * Architectures with slow multiplication can define
 110         * WANT_PAGE_VIRTUAL in asm/page.h
 111         */
 112#if defined(WANT_PAGE_VIRTUAL)
 113        void *virtual;                  /* Kernel virtual address (NULL if
 114                                           not kmapped, ie. highmem) */
 115#endif /* WANT_PAGE_VIRTUAL */
 116#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 117        unsigned long debug_flags;      /* Use atomic bitops on this */
 118#endif
 119
 120#ifdef CONFIG_KMEMCHECK
 121        /*
 122         * kmemcheck wants to track the status of each byte in a page; this
 123         * is a pointer to such a status block. NULL if not tracked.
 124         */
 125        void *shadow;
 126#endif
 127}
 128/*
 129 * If another subsystem starts using the double word pairing for atomic
 130 * operations on struct page then it must change the #if to ensure
 131 * proper alignment of the page struct.
 132 */
 133#if defined(CONFIG_SLUB) && defined(CONFIG_CMPXCHG_LOCAL)
 134        __attribute__((__aligned__(2*sizeof(unsigned long))))
 135#endif
 136;
 137
 138typedef unsigned long __nocast vm_flags_t;
 139
 140/*
 141 * A region containing a mapping of a non-memory backed file under NOMMU
 142 * conditions.  These are held in a global tree and are pinned by the VMAs that
 143 * map parts of them.
 144 */
 145struct vm_region {
 146        struct rb_node  vm_rb;          /* link in global region tree */
 147        vm_flags_t      vm_flags;       /* VMA vm_flags */
 148        unsigned long   vm_start;       /* start address of region */
 149        unsigned long   vm_end;         /* region initialised to here */
 150        unsigned long   vm_top;         /* region allocated to here */
 151        unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 152        struct file     *vm_file;       /* the backing file or NULL */
 153
 154        int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 155        bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 156                                                * this region */
 157};
 158
 159/*
 160 * This struct defines a memory VMM memory area. There is one of these
 161 * per VM-area/task.  A VM area is any part of the process virtual memory
 162 * space that has a special rule for the page-fault handlers (ie a shared
 163 * library, the executable area etc).
 164 */
 165struct vm_area_struct {
 166        struct mm_struct * vm_mm;       /* The address space we belong to. */
 167        unsigned long vm_start;         /* Our start address within vm_mm. */
 168        unsigned long vm_end;           /* The first byte after our end address
 169                                           within vm_mm. */
 170
 171        /* linked list of VM areas per task, sorted by address */
 172        struct vm_area_struct *vm_next, *vm_prev;
 173
 174        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 175        unsigned long vm_flags;         /* Flags, see mm.h. */
 176
 177        struct rb_node vm_rb;
 178
 179        /*
 180         * For areas with an address space and backing store,
 181         * linkage into the address_space->i_mmap prio tree, or
 182         * linkage to the list of like vmas hanging off its node, or
 183         * linkage of vma in the address_space->i_mmap_nonlinear list.
 184         */
 185        union {
 186                struct {
 187                        struct list_head list;
 188                        void *parent;   /* aligns with prio_tree_node parent */
 189                        struct vm_area_struct *head;
 190                } vm_set;
 191
 192                struct raw_prio_tree_node prio_tree_node;
 193        } shared;
 194
 195        /*
 196         * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 197         * list, after a COW of one of the file pages.  A MAP_SHARED vma
 198         * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 199         * or brk vma (with NULL file) can only be in an anon_vma list.
 200         */
 201        struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 202                                          * page_table_lock */
 203        struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 204
 205        /* Function pointers to deal with this struct. */
 206        const struct vm_operations_struct *vm_ops;
 207
 208        /* Information about our backing store: */
 209        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 210                                           units, *not* PAGE_CACHE_SIZE */
 211        struct file * vm_file;          /* File we map to (can be NULL). */
 212        void * vm_private_data;         /* was vm_pte (shared mem) */
 213
 214#ifndef CONFIG_MMU
 215        struct vm_region *vm_region;    /* NOMMU mapping region */
 216#endif
 217#ifdef CONFIG_NUMA
 218        struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 219#endif
 220};
 221
 222struct core_thread {
 223        struct task_struct *task;
 224        struct core_thread *next;
 225};
 226
 227struct core_state {
 228        atomic_t nr_threads;
 229        struct core_thread dumper;
 230        struct completion startup;
 231};
 232
 233enum {
 234        MM_FILEPAGES,
 235        MM_ANONPAGES,
 236        MM_SWAPENTS,
 237        NR_MM_COUNTERS
 238};
 239
 240#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 241#define SPLIT_RSS_COUNTING
 242/* per-thread cached information, */
 243struct task_rss_stat {
 244        int events;     /* for synchronization threshold */
 245        int count[NR_MM_COUNTERS];
 246};
 247#endif /* USE_SPLIT_PTLOCKS */
 248
 249struct mm_rss_stat {
 250        atomic_long_t count[NR_MM_COUNTERS];
 251};
 252
 253struct mm_struct {
 254        struct vm_area_struct * mmap;           /* list of VMAs */
 255        struct rb_root mm_rb;
 256        struct vm_area_struct * mmap_cache;     /* last find_vma result */
 257#ifdef CONFIG_MMU
 258        unsigned long (*get_unmapped_area) (struct file *filp,
 259                                unsigned long addr, unsigned long len,
 260                                unsigned long pgoff, unsigned long flags);
 261        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 262#endif
 263        unsigned long mmap_base;                /* base of mmap area */
 264        unsigned long task_size;                /* size of task vm space */
 265        unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 266        unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 267        pgd_t * pgd;
 268        atomic_t mm_users;                      /* How many users with user space? */
 269        atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 270        int map_count;                          /* number of VMAs */
 271
 272        spinlock_t page_table_lock;             /* Protects page tables and some counters */
 273        struct rw_semaphore mmap_sem;
 274
 275        struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 276                                                 * together off init_mm.mmlist, and are protected
 277                                                 * by mmlist_lock
 278                                                 */
 279
 280
 281        unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 282        unsigned long hiwater_vm;       /* High-water virtual memory usage */
 283
 284        unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 285        unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 286        unsigned long start_code, end_code, start_data, end_data;
 287        unsigned long start_brk, brk, start_stack;
 288        unsigned long arg_start, arg_end, env_start, env_end;
 289
 290        unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 291
 292        /*
 293         * Special counters, in some configurations protected by the
 294         * page_table_lock, in other configurations by being atomic.
 295         */
 296        struct mm_rss_stat rss_stat;
 297
 298        struct linux_binfmt *binfmt;
 299
 300        cpumask_var_t cpu_vm_mask_var;
 301
 302        /* Architecture-specific MM context */
 303        mm_context_t context;
 304
 305        /* Swap token stuff */
 306        /*
 307         * Last value of global fault stamp as seen by this process.
 308         * In other words, this value gives an indication of how long
 309         * it has been since this task got the token.
 310         * Look at mm/thrash.c
 311         */
 312        unsigned int faultstamp;
 313        unsigned int token_priority;
 314        unsigned int last_interval;
 315
 316        /* How many tasks sharing this mm are OOM_DISABLE */
 317        atomic_t oom_disable_count;
 318
 319        unsigned long flags; /* Must use atomic bitops to access the bits */
 320
 321        struct core_state *core_state; /* coredumping support */
 322#ifdef CONFIG_AIO
 323        spinlock_t              ioctx_lock;
 324        struct hlist_head       ioctx_list;
 325#endif
 326#ifdef CONFIG_MM_OWNER
 327        /*
 328         * "owner" points to a task that is regarded as the canonical
 329         * user/owner of this mm. All of the following must be true in
 330         * order for it to be changed:
 331         *
 332         * current == mm->owner
 333         * current->mm != mm
 334         * new_owner->mm == mm
 335         * new_owner->alloc_lock is held
 336         */
 337        struct task_struct __rcu *owner;
 338#endif
 339
 340        /* store ref to file /proc/<pid>/exe symlink points to */
 341        struct file *exe_file;
 342        unsigned long num_exe_file_vmas;
 343#ifdef CONFIG_MMU_NOTIFIER
 344        struct mmu_notifier_mm *mmu_notifier_mm;
 345#endif
 346#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 347        pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 348#endif
 349#ifdef CONFIG_CPUMASK_OFFSTACK
 350        struct cpumask cpumask_allocation;
 351#endif
 352};
 353
 354static inline void mm_init_cpumask(struct mm_struct *mm)
 355{
 356#ifdef CONFIG_CPUMASK_OFFSTACK
 357        mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 358#endif
 359}
 360
 361/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 362static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 363{
 364        return mm->cpu_vm_mask_var;
 365}
 366
 367#endif /* _LINUX_MM_TYPES_H */
 368