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