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/slob first free object */
  57                        bool pfmemalloc;        /* If set by the page allocator,
  58                                                 * ALLOC_NO_WATERMARKS was set
  59                                                 * and the low watermark was not
  60                                                 * met implying that the system
  61                                                 * is under some pressure. The
  62                                                 * caller should try ensure
  63                                                 * this page is only used to
  64                                                 * free other pages.
  65                                                 */
  66                };
  67
  68                union {
  69#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
  70        defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
  71                        /* Used for cmpxchg_double in slub */
  72                        unsigned long counters;
  73#else
  74                        /*
  75                         * Keep _count separate from slub cmpxchg_double data.
  76                         * As the rest of the double word is protected by
  77                         * slab_lock but _count is not.
  78                         */
  79                        unsigned counters;
  80#endif
  81
  82                        struct {
  83
  84                                union {
  85                                        /*
  86                                         * Count of ptes mapped in
  87                                         * mms, to show when page is
  88                                         * mapped & limit reverse map
  89                                         * searches.
  90                                         *
  91                                         * Used also for tail pages
  92                                         * refcounting instead of
  93                                         * _count. Tail pages cannot
  94                                         * be mapped and keeping the
  95                                         * tail page _count zero at
  96                                         * all times guarantees
  97                                         * get_page_unless_zero() will
  98                                         * never succeed on tail
  99                                         * pages.
 100                                         */
 101                                        atomic_t _mapcount;
 102
 103                                        struct { /* SLUB */
 104                                                unsigned inuse:16;
 105                                                unsigned objects:15;
 106                                                unsigned frozen:1;
 107                                        };
 108                                        int units;      /* SLOB */
 109                                };
 110                                atomic_t _count;                /* Usage count, see below. */
 111                        };
 112                };
 113        };
 114
 115        /* Third double word block */
 116        union {
 117                struct list_head lru;   /* Pageout list, eg. active_list
 118                                         * protected by zone->lru_lock !
 119                                         */
 120                struct {                /* slub per cpu partial pages */
 121                        struct page *next;      /* Next partial slab */
 122#ifdef CONFIG_64BIT
 123                        int pages;      /* Nr of partial slabs left */
 124                        int pobjects;   /* Approximate # of objects */
 125#else
 126                        short int pages;
 127                        short int pobjects;
 128#endif
 129                };
 130
 131                struct list_head list;  /* slobs list of pages */
 132                struct {                /* slab fields */
 133                        struct kmem_cache *slab_cache;
 134                        struct slab *slab_page;
 135                };
 136        };
 137
 138        /* Remainder is not double word aligned */
 139        union {
 140                unsigned long private;          /* Mapping-private opaque data:
 141                                                 * usually used for buffer_heads
 142                                                 * if PagePrivate set; used for
 143                                                 * swp_entry_t if PageSwapCache;
 144                                                 * indicates order in the buddy
 145                                                 * system if PG_buddy is set.
 146                                                 */
 147#if USE_SPLIT_PTLOCKS
 148                spinlock_t ptl;
 149#endif
 150                struct kmem_cache *slab;        /* SLUB: Pointer to slab */
 151                struct page *first_page;        /* Compound tail pages */
 152        };
 153
 154        /*
 155         * On machines where all RAM is mapped into kernel address space,
 156         * we can simply calculate the virtual address. On machines with
 157         * highmem some memory is mapped into kernel virtual memory
 158         * dynamically, so we need a place to store that address.
 159         * Note that this field could be 16 bits on x86 ... ;)
 160         *
 161         * Architectures with slow multiplication can define
 162         * WANT_PAGE_VIRTUAL in asm/page.h
 163         */
 164#if defined(WANT_PAGE_VIRTUAL)
 165        void *virtual;                  /* Kernel virtual address (NULL if
 166                                           not kmapped, ie. highmem) */
 167#endif /* WANT_PAGE_VIRTUAL */
 168#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 169        unsigned long debug_flags;      /* Use atomic bitops on this */
 170#endif
 171
 172#ifdef CONFIG_KMEMCHECK
 173        /*
 174         * kmemcheck wants to track the status of each byte in a page; this
 175         * is a pointer to such a status block. NULL if not tracked.
 176         */
 177        void *shadow;
 178#endif
 179}
 180/*
 181 * The struct page can be forced to be double word aligned so that atomic ops
 182 * on double words work. The SLUB allocator can make use of such a feature.
 183 */
 184#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
 185        __aligned(2 * sizeof(unsigned long))
 186#endif
 187;
 188
 189struct page_frag {
 190        struct page *page;
 191#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
 192        __u32 offset;
 193        __u32 size;
 194#else
 195        __u16 offset;
 196        __u16 size;
 197#endif
 198};
 199
 200typedef unsigned long __nocast vm_flags_t;
 201
 202/*
 203 * A region containing a mapping of a non-memory backed file under NOMMU
 204 * conditions.  These are held in a global tree and are pinned by the VMAs that
 205 * map parts of them.
 206 */
 207struct vm_region {
 208        struct rb_node  vm_rb;          /* link in global region tree */
 209        vm_flags_t      vm_flags;       /* VMA vm_flags */
 210        unsigned long   vm_start;       /* start address of region */
 211        unsigned long   vm_end;         /* region initialised to here */
 212        unsigned long   vm_top;         /* region allocated to here */
 213        unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 214        struct file     *vm_file;       /* the backing file or NULL */
 215
 216        int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 217        bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 218                                                * this region */
 219};
 220
 221/*
 222 * This struct defines a memory VMM memory area. There is one of these
 223 * per VM-area/task.  A VM area is any part of the process virtual memory
 224 * space that has a special rule for the page-fault handlers (ie a shared
 225 * library, the executable area etc).
 226 */
 227struct vm_area_struct {
 228        struct mm_struct * vm_mm;       /* The address space we belong to. */
 229        unsigned long vm_start;         /* Our start address within vm_mm. */
 230        unsigned long vm_end;           /* The first byte after our end address
 231                                           within vm_mm. */
 232
 233        /* linked list of VM areas per task, sorted by address */
 234        struct vm_area_struct *vm_next, *vm_prev;
 235
 236        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 237        unsigned long vm_flags;         /* Flags, see mm.h. */
 238
 239        struct rb_node vm_rb;
 240
 241        /*
 242         * For areas with an address space and backing store,
 243         * linkage into the address_space->i_mmap prio tree, or
 244         * linkage to the list of like vmas hanging off its node, or
 245         * linkage of vma in the address_space->i_mmap_nonlinear list.
 246         */
 247        union {
 248                struct {
 249                        struct list_head list;
 250                        void *parent;   /* aligns with prio_tree_node parent */
 251                        struct vm_area_struct *head;
 252                } vm_set;
 253
 254                struct raw_prio_tree_node prio_tree_node;
 255        } shared;
 256
 257        /*
 258         * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 259         * list, after a COW of one of the file pages.  A MAP_SHARED vma
 260         * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 261         * or brk vma (with NULL file) can only be in an anon_vma list.
 262         */
 263        struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 264                                          * page_table_lock */
 265        struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 266
 267        /* Function pointers to deal with this struct. */
 268        const struct vm_operations_struct *vm_ops;
 269
 270        /* Information about our backing store: */
 271        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 272                                           units, *not* PAGE_CACHE_SIZE */
 273        struct file * vm_file;          /* File we map to (can be NULL). */
 274        void * vm_private_data;         /* was vm_pte (shared mem) */
 275
 276#ifndef CONFIG_MMU
 277        struct vm_region *vm_region;    /* NOMMU mapping region */
 278#endif
 279#ifdef CONFIG_NUMA
 280        struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 281#endif
 282};
 283
 284struct core_thread {
 285        struct task_struct *task;
 286        struct core_thread *next;
 287};
 288
 289struct core_state {
 290        atomic_t nr_threads;
 291        struct core_thread dumper;
 292        struct completion startup;
 293};
 294
 295enum {
 296        MM_FILEPAGES,
 297        MM_ANONPAGES,
 298        MM_SWAPENTS,
 299        NR_MM_COUNTERS
 300};
 301
 302#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 303#define SPLIT_RSS_COUNTING
 304/* per-thread cached information, */
 305struct task_rss_stat {
 306        int events;     /* for synchronization threshold */
 307        int count[NR_MM_COUNTERS];
 308};
 309#endif /* USE_SPLIT_PTLOCKS */
 310
 311struct mm_rss_stat {
 312        atomic_long_t count[NR_MM_COUNTERS];
 313};
 314
 315struct mm_struct {
 316        struct vm_area_struct * mmap;           /* list of VMAs */
 317        struct rb_root mm_rb;
 318        struct vm_area_struct * mmap_cache;     /* last find_vma result */
 319#ifdef CONFIG_MMU
 320        unsigned long (*get_unmapped_area) (struct file *filp,
 321                                unsigned long addr, unsigned long len,
 322                                unsigned long pgoff, unsigned long flags);
 323        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 324#endif
 325        unsigned long mmap_base;                /* base of mmap area */
 326        unsigned long task_size;                /* size of task vm space */
 327        unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 328        unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 329        pgd_t * pgd;
 330        atomic_t mm_users;                      /* How many users with user space? */
 331        atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 332        int map_count;                          /* number of VMAs */
 333
 334        spinlock_t page_table_lock;             /* Protects page tables and some counters */
 335        struct rw_semaphore mmap_sem;
 336
 337        struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 338                                                 * together off init_mm.mmlist, and are protected
 339                                                 * by mmlist_lock
 340                                                 */
 341
 342
 343        unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 344        unsigned long hiwater_vm;       /* High-water virtual memory usage */
 345
 346        unsigned long total_vm;         /* Total pages mapped */
 347        unsigned long locked_vm;        /* Pages that have PG_mlocked set */
 348        unsigned long pinned_vm;        /* Refcount permanently increased */
 349        unsigned long shared_vm;        /* Shared pages (files) */
 350        unsigned long exec_vm;          /* VM_EXEC & ~VM_WRITE */
 351        unsigned long stack_vm;         /* VM_GROWSUP/DOWN */
 352        unsigned long reserved_vm;      /* VM_RESERVED|VM_IO pages */
 353        unsigned long def_flags;
 354        unsigned long nr_ptes;          /* Page table pages */
 355        unsigned long start_code, end_code, start_data, end_data;
 356        unsigned long start_brk, brk, start_stack;
 357        unsigned long arg_start, arg_end, env_start, env_end;
 358
 359        unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 360
 361        /*
 362         * Special counters, in some configurations protected by the
 363         * page_table_lock, in other configurations by being atomic.
 364         */
 365        struct mm_rss_stat rss_stat;
 366
 367        struct linux_binfmt *binfmt;
 368
 369        cpumask_var_t cpu_vm_mask_var;
 370
 371        /* Architecture-specific MM context */
 372        mm_context_t context;
 373
 374        unsigned long flags; /* Must use atomic bitops to access the bits */
 375
 376        struct core_state *core_state; /* coredumping support */
 377#ifdef CONFIG_AIO
 378        spinlock_t              ioctx_lock;
 379        struct hlist_head       ioctx_list;
 380#endif
 381#ifdef CONFIG_MM_OWNER
 382        /*
 383         * "owner" points to a task that is regarded as the canonical
 384         * user/owner of this mm. All of the following must be true in
 385         * order for it to be changed:
 386         *
 387         * current == mm->owner
 388         * current->mm != mm
 389         * new_owner->mm == mm
 390         * new_owner->alloc_lock is held
 391         */
 392        struct task_struct __rcu *owner;
 393#endif
 394
 395        /* store ref to file /proc/<pid>/exe symlink points to */
 396        struct file *exe_file;
 397        unsigned long num_exe_file_vmas;
 398#ifdef CONFIG_MMU_NOTIFIER
 399        struct mmu_notifier_mm *mmu_notifier_mm;
 400#endif
 401#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 402        pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 403#endif
 404#ifdef CONFIG_CPUMASK_OFFSTACK
 405        struct cpumask cpumask_allocation;
 406#endif
 407        struct uprobes_state uprobes_state;
 408};
 409
 410static inline void mm_init_cpumask(struct mm_struct *mm)
 411{
 412#ifdef CONFIG_CPUMASK_OFFSTACK
 413        mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 414#endif
 415}
 416
 417/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 418static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 419{
 420        return mm->cpu_vm_mask_var;
 421}
 422
 423#endif /* _LINUX_MM_TYPES_H */
 424
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