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 */
  34struct page {
  35        unsigned long flags;            /* Atomic flags, some possibly
  36                                         * updated asynchronously */
  37        atomic_t _count;                /* Usage count, see below. */
  38        union {
  39                atomic_t _mapcount;     /* Count of ptes mapped in mms,
  40                                         * to show when page is mapped
  41                                         * & limit reverse map searches.
  42                                         */
  43                struct {                /* SLUB */
  44                        u16 inuse;
  45                        u16 objects;
  46                };
  47        };
  48        union {
  49            struct {
  50                unsigned long private;          /* Mapping-private opaque data:
  51                                                 * usually used for buffer_heads
  52                                                 * if PagePrivate set; used for
  53                                                 * swp_entry_t if PageSwapCache;
  54                                                 * indicates order in the buddy
  55                                                 * system if PG_buddy is set.
  56                                                 */
  57                struct address_space *mapping;  /* If low bit clear, points to
  58                                                 * inode address_space, or NULL.
  59                                                 * If page mapped as anonymous
  60                                                 * memory, low bit is set, and
  61                                                 * it points to anon_vma object:
  62                                                 * see PAGE_MAPPING_ANON below.
  63                                                 */
  64            };
  65#if USE_SPLIT_PTLOCKS
  66            spinlock_t ptl;
  67#endif
  68            struct kmem_cache *slab;    /* SLUB: Pointer to slab */
  69            struct page *first_page;    /* Compound tail pages */
  70        };
  71        union {
  72                pgoff_t index;          /* Our offset within mapping. */
  73                void *freelist;         /* SLUB: freelist req. slab lock */
  74        };
  75        struct list_head lru;           /* Pageout list, eg. active_list
  76                                         * protected by zone->lru_lock !
  77                                         */
  78        /*
  79         * On machines where all RAM is mapped into kernel address space,
  80         * we can simply calculate the virtual address. On machines with
  81         * highmem some memory is mapped into kernel virtual memory
  82         * dynamically, so we need a place to store that address.
  83         * Note that this field could be 16 bits on x86 ... ;)
  84         *
  85         * Architectures with slow multiplication can define
  86         * WANT_PAGE_VIRTUAL in asm/page.h
  87         */
  88#if defined(WANT_PAGE_VIRTUAL)
  89        void *virtual;                  /* Kernel virtual address (NULL if
  90                                           not kmapped, ie. highmem) */
  91#endif /* WANT_PAGE_VIRTUAL */
  92#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
  93        unsigned long debug_flags;      /* Use atomic bitops on this */
  94#endif
  95
  96#ifdef CONFIG_KMEMCHECK
  97        /*
  98         * kmemcheck wants to track the status of each byte in a page; this
  99         * is a pointer to such a status block. NULL if not tracked.
 100         */
 101        void *shadow;
 102#endif
 103};
 104
 105/*
 106 * A region containing a mapping of a non-memory backed file under NOMMU
 107 * conditions.  These are held in a global tree and are pinned by the VMAs that
 108 * map parts of them.
 109 */
 110struct vm_region {
 111        struct rb_node  vm_rb;          /* link in global region tree */
 112        unsigned long   vm_flags;       /* VMA vm_flags */
 113        unsigned long   vm_start;       /* start address of region */
 114        unsigned long   vm_end;         /* region initialised to here */
 115        unsigned long   vm_top;         /* region allocated to here */
 116        unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 117        struct file     *vm_file;       /* the backing file or NULL */
 118
 119        int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 120        bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 121                                                * this region */
 122};
 123
 124/*
 125 * This struct defines a memory VMM memory area. There is one of these
 126 * per VM-area/task.  A VM area is any part of the process virtual memory
 127 * space that has a special rule for the page-fault handlers (ie a shared
 128 * library, the executable area etc).
 129 */
 130struct vm_area_struct {
 131        struct mm_struct * vm_mm;       /* The address space we belong to. */
 132        unsigned long vm_start;         /* Our start address within vm_mm. */
 133        unsigned long vm_end;           /* The first byte after our end address
 134                                           within vm_mm. */
 135
 136        /* linked list of VM areas per task, sorted by address */
 137        struct vm_area_struct *vm_next, *vm_prev;
 138
 139        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 140        unsigned long vm_flags;         /* Flags, see mm.h. */
 141
 142        struct rb_node vm_rb;
 143
 144        /*
 145         * For areas with an address space and backing store,
 146         * linkage into the address_space->i_mmap prio tree, or
 147         * linkage to the list of like vmas hanging off its node, or
 148         * linkage of vma in the address_space->i_mmap_nonlinear list.
 149         */
 150        union {
 151                struct {
 152                        struct list_head list;
 153                        void *parent;   /* aligns with prio_tree_node parent */
 154                        struct vm_area_struct *head;
 155                } vm_set;
 156
 157                struct raw_prio_tree_node prio_tree_node;
 158        } shared;
 159
 160        /*
 161         * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 162         * list, after a COW of one of the file pages.  A MAP_SHARED vma
 163         * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 164         * or brk vma (with NULL file) can only be in an anon_vma list.
 165         */
 166        struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 167                                          * page_table_lock */
 168        struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 169
 170        /* Function pointers to deal with this struct. */
 171        const struct vm_operations_struct *vm_ops;
 172
 173        /* Information about our backing store: */
 174        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 175                                           units, *not* PAGE_CACHE_SIZE */
 176        struct file * vm_file;          /* File we map to (can be NULL). */
 177        void * vm_private_data;         /* was vm_pte (shared mem) */
 178        unsigned long vm_truncate_count;/* truncate_count or restart_addr */
 179
 180#ifndef CONFIG_MMU
 181        struct vm_region *vm_region;    /* NOMMU mapping region */
 182#endif
 183#ifdef CONFIG_NUMA
 184        struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 185#endif
 186};
 187
 188struct core_thread {
 189        struct task_struct *task;
 190        struct core_thread *next;
 191};
 192
 193struct core_state {
 194        atomic_t nr_threads;
 195        struct core_thread dumper;
 196        struct completion startup;
 197};
 198
 199enum {
 200        MM_FILEPAGES,
 201        MM_ANONPAGES,
 202        MM_SWAPENTS,
 203        NR_MM_COUNTERS
 204};
 205
 206#if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
 207#define SPLIT_RSS_COUNTING
 208struct mm_rss_stat {
 209        atomic_long_t count[NR_MM_COUNTERS];
 210};
 211/* per-thread cached information, */
 212struct task_rss_stat {
 213        int events;     /* for synchronization threshold */
 214        int count[NR_MM_COUNTERS];
 215};
 216#else  /* !USE_SPLIT_PTLOCKS */
 217struct mm_rss_stat {
 218        unsigned long count[NR_MM_COUNTERS];
 219};
 220#endif /* !USE_SPLIT_PTLOCKS */
 221
 222struct mm_struct {
 223        struct vm_area_struct * mmap;           /* list of VMAs */
 224        struct rb_root mm_rb;
 225        struct vm_area_struct * mmap_cache;     /* last find_vma result */
 226#ifdef CONFIG_MMU
 227        unsigned long (*get_unmapped_area) (struct file *filp,
 228                                unsigned long addr, unsigned long len,
 229                                unsigned long pgoff, unsigned long flags);
 230        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
 231#endif
 232        unsigned long mmap_base;                /* base of mmap area */
 233        unsigned long task_size;                /* size of task vm space */
 234        unsigned long cached_hole_size;         /* if non-zero, the largest hole below free_area_cache */
 235        unsigned long free_area_cache;          /* first hole of size cached_hole_size or larger */
 236        pgd_t * pgd;
 237        atomic_t mm_users;                      /* How many users with user space? */
 238        atomic_t mm_count;                      /* How many references to "struct mm_struct" (users count as 1) */
 239        int map_count;                          /* number of VMAs */
 240        struct rw_semaphore mmap_sem;
 241        spinlock_t page_table_lock;             /* Protects page tables and some counters */
 242
 243        struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 244                                                 * together off init_mm.mmlist, and are protected
 245                                                 * by mmlist_lock
 246                                                 */
 247
 248
 249        unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 250        unsigned long hiwater_vm;       /* High-water virtual memory usage */
 251
 252        unsigned long total_vm, locked_vm, shared_vm, exec_vm;
 253        unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
 254        unsigned long start_code, end_code, start_data, end_data;
 255        unsigned long start_brk, brk, start_stack;
 256        unsigned long arg_start, arg_end, env_start, env_end;
 257
 258        unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 259
 260        /*
 261         * Special counters, in some configurations protected by the
 262         * page_table_lock, in other configurations by being atomic.
 263         */
 264        struct mm_rss_stat rss_stat;
 265
 266        struct linux_binfmt *binfmt;
 267
 268        cpumask_t cpu_vm_mask;
 269
 270        /* Architecture-specific MM context */
 271        mm_context_t context;
 272
 273        /* Swap token stuff */
 274        /*
 275         * Last value of global fault stamp as seen by this process.
 276         * In other words, this value gives an indication of how long
 277         * it has been since this task got the token.
 278         * Look at mm/thrash.c
 279         */
 280        unsigned int faultstamp;
 281        unsigned int token_priority;
 282        unsigned int last_interval;
 283
 284        unsigned long flags; /* Must use atomic bitops to access the bits */
 285
 286        struct core_state *core_state; /* coredumping support */
 287#ifdef CONFIG_AIO
 288        spinlock_t              ioctx_lock;
 289        struct hlist_head       ioctx_list;
 290#endif
 291#ifdef CONFIG_MM_OWNER
 292        /*
 293         * "owner" points to a task that is regarded as the canonical
 294         * user/owner of this mm. All of the following must be true in
 295         * order for it to be changed:
 296         *
 297         * current == mm->owner
 298         * current->mm != mm
 299         * new_owner->mm == mm
 300         * new_owner->alloc_lock is held
 301         */
 302        struct task_struct __rcu *owner;
 303#endif
 304
 305#ifdef CONFIG_PROC_FS
 306        /* store ref to file /proc/<pid>/exe symlink points to */
 307        struct file *exe_file;
 308        unsigned long num_exe_file_vmas;
 309#endif
 310#ifdef CONFIG_MMU_NOTIFIER
 311        struct mmu_notifier_mm *mmu_notifier_mm;
 312#endif
 313        /* How many tasks sharing this mm are OOM_DISABLE */
 314        atomic_t oom_disable_count;
 315};
 316
 317/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 318#define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
 319
 320#endif /* _LINUX_MM_TYPES_H */
 321
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