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        struct list_head lru;           /* Pageout list, eg. active_list
  96                                         * protected by zone->lru_lock !
  97                                         */
  98
  99        /* Remainder is not double word aligned */
 100        union {
 101                unsigned long private;          /* Mapping-private opaque data:
 102                                                 * usually used for buffer_heads
 103                                                 * if PagePrivate set; used for
 104                                                 * swp_entry_t if PageSwapCache;
 105                                                 * indicates order in the buddy
 106                                                 * system if PG_buddy is set.
 107                                                 */
 108#if USE_SPLIT_PTLOCKS
 109                spinlock_t ptl;
 110#endif
 111                struct kmem_cache *slab;        /* SLUB: Pointer to slab */
 112                struct page *first_page;        /* Compound tail pages */
 113        };
 114
 115        /*
 116         * On machines where all RAM is mapped into kernel address space,
 117         * we can simply calculate the virtual address. On machines with
 118         * highmem some memory is mapped into kernel virtual memory
 119         * dynamically, so we need a place to store that address.
 120         * Note that this field could be 16 bits on x86 ... ;)
 121         *
 122         * Architectures with slow multiplication can define
 123         * WANT_PAGE_VIRTUAL in asm/page.h
 124         */
 125#if defined(WANT_PAGE_VIRTUAL)
 126        void *virtual;                  /* Kernel virtual address (NULL if
 127                                           not kmapped, ie. highmem) */
 128#endif /* WANT_PAGE_VIRTUAL */
 129#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
 130        unsigned long debug_flags;      /* Use atomic bitops on this */
 131#endif
 132
 133#ifdef CONFIG_KMEMCHECK
 134        /*
 135         * kmemcheck wants to track the status of each byte in a page; this
 136         * is a pointer to such a status block. NULL if not tracked.
 137         */
 138        void *shadow;
 139#endif
 140}
 141/*
 142 * If another subsystem starts using the double word pairing for atomic
 143 * operations on struct page then it must change the #if to ensure
 144 * proper alignment of the page struct.
 145 */
 146#if defined(CONFIG_SLUB) && defined(CONFIG_CMPXCHG_LOCAL)
 147        __attribute__((__aligned__(2*sizeof(unsigned long))))
 148#endif
 149;
 150
 151typedef unsigned long __nocast vm_flags_t;
 152
 153/*
 154 * A region containing a mapping of a non-memory backed file under NOMMU
 155 * conditions.  These are held in a global tree and are pinned by the VMAs that
 156 * map parts of them.
 157 */
 158struct vm_region {
 159        struct rb_node  vm_rb;          /* link in global region tree */
 160        vm_flags_t      vm_flags;       /* VMA vm_flags */
 161        unsigned long   vm_start;       /* start address of region */
 162        unsigned long   vm_end;         /* region initialised to here */
 163        unsigned long   vm_top;         /* region allocated to here */
 164        unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 165        struct file     *vm_file;       /* the backing file or NULL */
 166
 167        int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 168        bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 169                                                * this region */
 170};
 171
 172/*
 173 * This struct defines a memory VMM memory area. There is one of these
 174 * per VM-area/task.  A VM area is any part of the process virtual memory
 175 * space that has a special rule for the page-fault handlers (ie a shared
 176 * library, the executable area etc).
 177 */
 178struct vm_area_struct {
 179        struct mm_struct * vm_mm;       /* The address space we belong to. */
 180        unsigned long vm_start;         /* Our start address within vm_mm. */
 181        unsigned long vm_end;           /* The first byte after our end address
 182                                           within vm_mm. */
 183
 184        /* linked list of VM areas per task, sorted by address */
 185        struct vm_area_struct *vm_next, *vm_prev;
 186
 187        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 188        unsigned long vm_flags;         /* Flags, see mm.h. */
 189
 190        struct rb_node vm_rb;
 191
 192        /*
 193         * For areas with an address space and backing store,
 194         * linkage into the address_space->i_mmap prio tree, or
 195         * linkage to the list of like vmas hanging off its node, or
 196         * linkage of vma in the address_space->i_mmap_nonlinear list.
 197         */
 198        union {
 199                struct {
 200                        struct list_head list;
 201                        void *parent;   /* aligns with prio_tree_node parent */
 202                        struct vm_area_struct *head;
 203                } vm_set;
 204
 205                struct raw_prio_tree_node prio_tree_node;
 206        } shared;
 207
 208        /*
 209         * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 210         * list, after a COW of one of the file pages.  A MAP_SHARED vma
 211         * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 212         * or brk vma (with NULL file) can only be in an anon_vma list.
 213         */
 214        struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 215                                          * page_table_lock */
 216        struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 217
 218        /* Function pointers to deal with this struct. */
 219        const struct vm_operations_struct *vm_ops;
 220
 221        /* Information about our backing store: */
 222        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 223                                           units, *not* PAGE_CACHE_SIZE */
 224        struct file * vm_file;          /* File we map to (can be NULL). */
 225        void * vm_private_data;         /* was vm_pte (shared mem) */
 226
 227#ifndef CONFIG_MMU
 228        struct vm_region *vm_region;    /* NOMMU mapping region */
 229#endif
 230#ifdef CONFIG_NUMA
 231        struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 232#endif
 233};
 234
 235struct core_thread {
 236        struct task_struct *task;
 237        struct core_thread *next;
 238};
 239
 240struct core_state {
 241        atomic_t nr_threads;
 242        struct core_thread dumper;
 243        struct completion startup;
 244};
 245
 246enum {
 247        MM_FILEPAGES,
 248        MM_ANONPAGES,
 249        MM_SWAPENTS,
 250        NR_MM_COUNTERS
 251};
 252
 253#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 254#define SPLIT_RSS_COUNTING
 255/* per-thread cached information, */
 256struct task_rss_stat {
 257        int events;     /* for synchronization threshold */
 258        int count[NR_MM_COUNTERS];
 259};
 260#endif /* USE_SPLIT_PTLOCKS */
 261
 262struct mm_rss_stat {
 263        atomic_long_t count[NR_MM_COUNTERS];
 264};
 265
 266struct mm_struct {
 267        struct vm_area_struct * mmap;           /* list of VMAs */
 268        struct rb_root mm_rb;
 269        struct vm_area_struct * mmap_cache;     /* last find_vma result */
 270#ifdef CONFIG_MMU
 271        unsigned long (*get_unmapped_area) (struct file *filp,
 272                                unsigned long addr, unsigned long len,
 273                                unsigned long pgoff, unsigned long flags);
 274        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 275#endif
 276        unsigned long mmap_base;                /* base of mmap area */
 277        unsigned long task_size;                /* size of task vm space */
 278        unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 279        unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 280        pgd_t * pgd;
 281        atomic_t mm_users;                      /* How many users with user space? */
 282        atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 283        int map_count;                          /* number of VMAs */
 284
 285        spinlock_t page_table_lock;             /* Protects page tables and some counters */
 286        struct rw_semaphore mmap_sem;
 287
 288        struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 289                                                 * together off init_mm.mmlist, and are protected
 290                                                 * by mmlist_lock
 291                                                 */
 292
 293
 294        unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 295        unsigned long hiwater_vm;       /* High-water virtual memory usage */
 296
 297        unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 298        unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 299        unsigned long start_code, end_code, start_data, end_data;
 300        unsigned long start_brk, brk, start_stack;
 301        unsigned long arg_start, arg_end, env_start, env_end;
 302
 303        unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 304
 305        /*
 306         * Special counters, in some configurations protected by the
 307         * page_table_lock, in other configurations by being atomic.
 308         */
 309        struct mm_rss_stat rss_stat;
 310
 311        struct linux_binfmt *binfmt;
 312
 313        cpumask_var_t cpu_vm_mask_var;
 314
 315        /* Architecture-specific MM context */
 316        mm_context_t context;
 317
 318        /* Swap token stuff */
 319        /*
 320         * Last value of global fault stamp as seen by this process.
 321         * In other words, this value gives an indication of how long
 322         * it has been since this task got the token.
 323         * Look at mm/thrash.c
 324         */
 325        unsigned int faultstamp;
 326        unsigned int token_priority;
 327        unsigned int last_interval;
 328
 329        /* How many tasks sharing this mm are OOM_DISABLE */
 330        atomic_t oom_disable_count;
 331
 332        unsigned long flags; /* Must use atomic bitops to access the bits */
 333
 334        struct core_state *core_state; /* coredumping support */
 335#ifdef CONFIG_AIO
 336        spinlock_t              ioctx_lock;
 337        struct hlist_head       ioctx_list;
 338#endif
 339#ifdef CONFIG_MM_OWNER
 340        /*
 341         * "owner" points to a task that is regarded as the canonical
 342         * user/owner of this mm. All of the following must be true in
 343         * order for it to be changed:
 344         *
 345         * current == mm->owner
 346         * current->mm != mm
 347         * new_owner->mm == mm
 348         * new_owner->alloc_lock is held
 349         */
 350        struct task_struct __rcu *owner;
 351#endif
 352
 353        /* store ref to file /proc/<pid>/exe symlink points to */
 354        struct file *exe_file;
 355        unsigned long num_exe_file_vmas;
 356#ifdef CONFIG_MMU_NOTIFIER
 357        struct mmu_notifier_mm *mmu_notifier_mm;
 358#endif
 359#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 360        pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 361#endif
 362#ifdef CONFIG_CPUMASK_OFFSTACK
 363        struct cpumask cpumask_allocation;
 364#endif
 365};
 366
 367static inline void mm_init_cpumask(struct mm_struct *mm)
 368{
 369#ifdef CONFIG_CPUMASK_OFFSTACK
 370        mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 371#endif
 372}
 373
 374/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 375static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 376{
 377        return mm->cpu_vm_mask_var;
 378}
 379
 380#endif /* _LINUX_MM_TYPES_H */
 381
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