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 <linux/uprobes.h>
  16#include <asm/page.h>
  17#include <asm/mmu.h>
  18
  19#ifndef AT_VECTOR_SIZE_ARCH
  20#define AT_VECTOR_SIZE_ARCH 0
  21#endif
  22#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
  23
  24struct address_space;
  25
  26#define USE_SPLIT_PTLOCKS       (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
  27
  28/*
  29 * Each physical page in the system has a struct page associated with
  30 * it to keep track of whatever it is we are using the page for at the
  31 * moment. Note that we have no way to track which tasks are using
  32 * a page, though if it is a pagecache page, rmap structures can tell us
  33 * who is mapping it.
  34 *
  35 * The objects in struct page are organized in double word blocks in
  36 * order to allows us to use atomic double word operations on portions
  37 * of struct page. That is currently only used by slub but the arrangement
  38 * allows the use of atomic double word operations on the flags/mapping
  39 * and lru list pointers also.
  40 */
  41struct page {
  42        /* First double word block */
  43        unsigned long flags;            /* Atomic flags, some possibly
  44                                         * updated asynchronously */
  45        struct address_space *mapping;  /* If low bit clear, points to
  46                                         * inode address_space, or NULL.
  47                                         * If page mapped as anonymous
  48                                         * memory, low bit is set, and
  49                                         * it points to anon_vma object:
  50                                         * see PAGE_MAPPING_ANON below.
  51                                         */
  52        /* Second double word */
  53        struct {
  54                union {
  55                        pgoff_t index;          /* Our offset within mapping. */
  56                        void *freelist;         /* slub first free object */
  57                };
  58
  59                union {
  60#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
  61        defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
  62                        /* Used for cmpxchg_double in slub */
  63                        unsigned long counters;
  64#else
  65                        /*
  66                         * Keep _count separate from slub cmpxchg_double data.
  67                         * As the rest of the double word is protected by
  68                         * slab_lock but _count is not.
  69                         */
  70                        unsigned counters;
  71#endif
  72
  73                        struct {
  74
  75                                union {
  76                                        /*
  77                                         * Count of ptes mapped in
  78                                         * mms, to show when page is
  79                                         * mapped & limit reverse map
  80                                         * searches.
  81                                         *
  82                                         * Used also for tail pages
  83                                         * refcounting instead of
  84                                         * _count. Tail pages cannot
  85                                         * be mapped and keeping the
  86                                         * tail page _count zero at
  87                                         * all times guarantees
  88                                         * get_page_unless_zero() will
  89                                         * never succeed on tail
  90                                         * pages.
  91                                         */
  92                                        atomic_t _mapcount;
  93
  94                                        struct {
  95                                                unsigned inuse:16;
  96                                                unsigned objects:15;
  97                                                unsigned frozen:1;
  98                                        };
  99                                };
 100                                atomic_t _count;                /* Usage count, see below. */
 101                        };
 102                };
 103        };
 104
 105        /* Third double word block */
 106        union {
 107                struct list_head lru;   /* Pageout list, eg. active_list
 108                                         * protected by zone->lru_lock !
 109                                         */
 110                struct {                /* slub per cpu partial pages */
 111                        struct page *next;      /* Next partial slab */
 112#ifdef CONFIG_64BIT
 113                        int pages;      /* Nr of partial slabs left */
 114                        int pobjects;   /* Approximate # of objects */
 115#else
 116                        short int pages;
 117                        short int pobjects;
 118#endif
 119                };
 120        };
 121
 122        /* Remainder is not double word aligned */
 123        union {
 124                unsigned long private;          /* Mapping-private opaque data:
 125                                                 * usually used for buffer_heads
 126                                                 * if PagePrivate set; used for
 127                                                 * swp_entry_t if PageSwapCache;
 128                                                 * indicates order in the buddy
 129                                                 * system if PG_buddy is set.
 130                                                 */
 131#if USE_SPLIT_PTLOCKS
 132                spinlock_t ptl;
 133#endif
 134                struct kmem_cache *slab;        /* SLUB: Pointer to slab */
 135                struct page *first_page;        /* Compound tail pages */
 136        };
 137
 138        /*
 139         * On machines where all RAM is mapped into kernel address space,
 140         * we can simply calculate the virtual address. On machines with
 141         * highmem some memory is mapped into kernel virtual memory
 142         * dynamically, so we need a place to store that address.
 143         * Note that this field could be 16 bits on x86 ... ;)
 144         *
 145         * Architectures with slow multiplication can define
 146         * WANT_PAGE_VIRTUAL in asm/page.h
 147         */
 148#if defined(WANT_PAGE_VIRTUAL)
 149        void *virtual;                  /* Kernel virtual address (NULL if
 150                                           not kmapped, ie. highmem) */
 151#endif /* WANT_PAGE_VIRTUAL */
 152#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 153        unsigned long debug_flags;      /* Use atomic bitops on this */
 154#endif
 155
 156#ifdef CONFIG_KMEMCHECK
 157        /*
 158         * kmemcheck wants to track the status of each byte in a page; this
 159         * is a pointer to such a status block. NULL if not tracked.
 160         */
 161        void *shadow;
 162#endif
 163}
 164/*
 165 * The struct page can be forced to be double word aligned so that atomic ops
 166 * on double words work. The SLUB allocator can make use of such a feature.
 167 */
 168#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
 169        __aligned(2 * sizeof(unsigned long))
 170#endif
 171;
 172
 173struct page_frag {
 174        struct page *page;
 175#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
 176        __u32 offset;
 177        __u32 size;
 178#else
 179        __u16 offset;
 180        __u16 size;
 181#endif
 182};
 183
 184typedef unsigned long __nocast vm_flags_t;
 185
 186/*
 187 * A region containing a mapping of a non-memory backed file under NOMMU
 188 * conditions.  These are held in a global tree and are pinned by the VMAs that
 189 * map parts of them.
 190 */
 191struct vm_region {
 192        struct rb_node  vm_rb;          /* link in global region tree */
 193        vm_flags_t      vm_flags;       /* VMA vm_flags */
 194        unsigned long   vm_start;       /* start address of region */
 195        unsigned long   vm_end;         /* region initialised to here */
 196        unsigned long   vm_top;         /* region allocated to here */
 197        unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 198        struct file     *vm_file;       /* the backing file or NULL */
 199
 200        int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 201        bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 202                                                * this region */
 203};
 204
 205/*
 206 * This struct defines a memory VMM memory area. There is one of these
 207 * per VM-area/task.  A VM area is any part of the process virtual memory
 208 * space that has a special rule for the page-fault handlers (ie a shared
 209 * library, the executable area etc).
 210 */
 211struct vm_area_struct {
 212        struct mm_struct * vm_mm;       /* The address space we belong to. */
 213        unsigned long vm_start;         /* Our start address within vm_mm. */
 214        unsigned long vm_end;           /* The first byte after our end address
 215                                           within vm_mm. */
 216
 217        /* linked list of VM areas per task, sorted by address */
 218        struct vm_area_struct *vm_next, *vm_prev;
 219
 220        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 221        unsigned long vm_flags;         /* Flags, see mm.h. */
 222
 223        struct rb_node vm_rb;
 224
 225        /*
 226         * For areas with an address space and backing store,
 227         * linkage into the address_space->i_mmap prio tree, or
 228         * linkage to the list of like vmas hanging off its node, or
 229         * linkage of vma in the address_space->i_mmap_nonlinear list.
 230         */
 231        union {
 232                struct {
 233                        struct list_head list;
 234                        void *parent;   /* aligns with prio_tree_node parent */
 235                        struct vm_area_struct *head;
 236                } vm_set;
 237
 238                struct raw_prio_tree_node prio_tree_node;
 239        } shared;
 240
 241        /*
 242         * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 243         * list, after a COW of one of the file pages.  A MAP_SHARED vma
 244         * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 245         * or brk vma (with NULL file) can only be in an anon_vma list.
 246         */
 247        struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 248                                          * page_table_lock */
 249        struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 250
 251        /* Function pointers to deal with this struct. */
 252        const struct vm_operations_struct *vm_ops;
 253
 254        /* Information about our backing store: */
 255        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 256                                           units, *not* PAGE_CACHE_SIZE */
 257        struct file * vm_file;          /* File we map to (can be NULL). */
 258        void * vm_private_data;         /* was vm_pte (shared mem) */
 259
 260#ifndef CONFIG_MMU
 261        struct vm_region *vm_region;    /* NOMMU mapping region */
 262#endif
 263#ifdef CONFIG_NUMA
 264        struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 265#endif
 266};
 267
 268struct core_thread {
 269        struct task_struct *task;
 270        struct core_thread *next;
 271};
 272
 273struct core_state {
 274        atomic_t nr_threads;
 275        struct core_thread dumper;
 276        struct completion startup;
 277};
 278
 279enum {
 280        MM_FILEPAGES,
 281        MM_ANONPAGES,
 282        MM_SWAPENTS,
 283        NR_MM_COUNTERS
 284};
 285
 286#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 287#define SPLIT_RSS_COUNTING
 288/* per-thread cached information, */
 289struct task_rss_stat {
 290        int events;     /* for synchronization threshold */
 291        int count[NR_MM_COUNTERS];
 292};
 293#endif /* USE_SPLIT_PTLOCKS */
 294
 295struct mm_rss_stat {
 296        atomic_long_t count[NR_MM_COUNTERS];
 297};
 298
 299struct mm_struct {
 300        struct vm_area_struct * mmap;           /* list of VMAs */
 301        struct rb_root mm_rb;
 302        struct vm_area_struct * mmap_cache;     /* last find_vma result */
 303#ifdef CONFIG_MMU
 304        unsigned long (*get_unmapped_area) (struct file *filp,
 305                                unsigned long addr, unsigned long len,
 306                                unsigned long pgoff, unsigned long flags);
 307        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 308#endif
 309        unsigned long mmap_base;                /* base of mmap area */
 310        unsigned long task_size;                /* size of task vm space */
 311        unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 312        unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 313        pgd_t * pgd;
 314        atomic_t mm_users;                      /* How many users with user space? */
 315        atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 316        int map_count;                          /* number of VMAs */
 317
 318        spinlock_t page_table_lock;             /* Protects page tables and some counters */
 319        struct rw_semaphore mmap_sem;
 320
 321        struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 322                                                 * together off init_mm.mmlist, and are protected
 323                                                 * by mmlist_lock
 324                                                 */
 325
 326
 327        unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 328        unsigned long hiwater_vm;       /* High-water virtual memory usage */
 329
 330        unsigned long total_vm;         /* Total pages mapped */
 331        unsigned long locked_vm;        /* Pages that have PG_mlocked set */
 332        unsigned long pinned_vm;        /* Refcount permanently increased */
 333        unsigned long shared_vm;        /* Shared pages (files) */
 334        unsigned long exec_vm;          /* VM_EXEC & ~VM_WRITE */
 335        unsigned long stack_vm;         /* VM_GROWSUP/DOWN */
 336        unsigned long reserved_vm;      /* VM_RESERVED|VM_IO pages */
 337        unsigned long def_flags;
 338        unsigned long nr_ptes;          /* Page table pages */
 339        unsigned long start_code, end_code, start_data, end_data;
 340        unsigned long start_brk, brk, start_stack;
 341        unsigned long arg_start, arg_end, env_start, env_end;
 342
 343        unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 344
 345        /*
 346         * Special counters, in some configurations protected by the
 347         * page_table_lock, in other configurations by being atomic.
 348         */
 349        struct mm_rss_stat rss_stat;
 350
 351        struct linux_binfmt *binfmt;
 352
 353        cpumask_var_t cpu_vm_mask_var;
 354
 355        /* Architecture-specific MM context */
 356        mm_context_t context;
 357
 358        unsigned long flags; /* Must use atomic bitops to access the bits */
 359
 360        struct core_state *core_state; /* coredumping support */
 361#ifdef CONFIG_AIO
 362        spinlock_t              ioctx_lock;
 363        struct hlist_head       ioctx_list;
 364#endif
 365#ifdef CONFIG_MM_OWNER
 366        /*
 367         * "owner" points to a task that is regarded as the canonical
 368         * user/owner of this mm. All of the following must be true in
 369         * order for it to be changed:
 370         *
 371         * current == mm->owner
 372         * current->mm != mm
 373         * new_owner->mm == mm
 374         * new_owner->alloc_lock is held
 375         */
 376        struct task_struct __rcu *owner;
 377#endif
 378
 379        /* store ref to file /proc/<pid>/exe symlink points to */
 380        struct file *exe_file;
 381        unsigned long num_exe_file_vmas;
 382#ifdef CONFIG_MMU_NOTIFIER
 383        struct mmu_notifier_mm *mmu_notifier_mm;
 384#endif
 385#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 386        pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 387#endif
 388#ifdef CONFIG_CPUMASK_OFFSTACK
 389        struct cpumask cpumask_allocation;
 390#endif
 391        struct uprobes_state uprobes_state;
 392};
 393
 394static inline void mm_init_cpumask(struct mm_struct *mm)
 395{
 396#ifdef CONFIG_CPUMASK_OFFSTACK
 397        mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 398#endif
 399}
 400
 401/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 402static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 403{
 404        return mm->cpu_vm_mask_var;
 405}
 406
 407#endif /* _LINUX_MM_TYPES_H */
 408