include/linux/mm_types.h

   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/rbtree.h>
  10 #include <linux/rwsem.h>
  11 #include <linux/completion.h>
  12 #include <linux/cpumask.h>
  13 #include <linux/uprobes.h>
  14 #include <linux/page-flags-layout.h>
  15 #include <linux/workqueue.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
  24 struct address_space;
  25 struct mem_cgroup;
  26
  27 #define USE_SPLIT_PTE_PTLOCKS   (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
  28 #define USE_SPLIT_PMD_PTLOCKS   (USE_SPLIT_PTE_PTLOCKS && \
  29                 IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
  30 #define ALLOC_SPLIT_PTLOCKS     (SPINLOCK_SIZE > BITS_PER_LONG/8)
  31
  32 /*
  33  * Each physical page in the system has a struct page associated with
  34  * it to keep track of whatever it is we are using the page for at the
  35  * moment. Note that we have no way to track which tasks are using
  36  * a page, though if it is a pagecache page, rmap structures can tell us
  37  * who is mapping it.
  38  *
  39  * The objects in struct page are organized in double word blocks in
  40  * order to allows us to use atomic double word operations on portions
  41  * of struct page. That is currently only used by slub but the arrangement
  42  * allows the use of atomic double word operations on the flags/mapping
  43  * and lru list pointers also.
  44  */
  45 struct page {
  46         /* First double word block */
  47         unsigned long flags;            /* Atomic flags, some possibly
  48                                          * updated asynchronously */
  49         union {
  50                 struct address_space *mapping;  /* If low bit clear, points to
  51                                                  * inode address_space, or NULL.
  52                                                  * If page mapped as anonymous
  53                                                  * memory, low bit is set, and
  54                                                  * it points to anon_vma object:
  55                                                  * see PAGE_MAPPING_ANON below.
  56                                                  */
  57                 void *s_mem;                    /* slab first object */
  58                 atomic_t compound_mapcount;     /* first tail page */
  59                 /* page_deferred_list().next     -- second tail page */
  60         };
  61
  62         /* Second double word */
  63         union {
  64                 pgoff_t index;          /* Our offset within mapping. */
  65                 void *freelist;         /* sl[aou]b first free object */
  66                 /* page_deferred_list().prev    -- second tail page */
  67         };
  68
  69         union {
  70 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
  71         defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
  72                 /* Used for cmpxchg_double in slub */
  73                 unsigned long counters;
  74 #else
  75                 /*
  76                  * Keep _refcount separate from slub cmpxchg_double data.
  77                  * As the rest of the double word is protected by slab_lock
  78                  * but _refcount is not.
  79                  */
  80                 unsigned counters;
  81 #endif
  82                 struct {
  83
  84                         union {
  85                                 /*
  86                                  * Count of ptes mapped in mms, to show when
  87                                  * page is mapped & limit reverse map searches.
  88                                  *
  89                                  * Extra information about page type may be
  90                                  * stored here for pages that are never mapped,
  91                                  * in which case the value MUST BE <= -2.
  92                                  * See page-flags.h for more details.
  93                                  */
  94                                 atomic_t _mapcount;
  95
  96                                 unsigned int active;            /* SLAB */
  97                                 struct {                        /* SLUB */
  98                                         unsigned inuse:16;
  99                                         unsigned objects:15;
 100                                         unsigned frozen:1;
 101                                 };
 102                                 int units;                      /* SLOB */
 103                         };
 104                         /*
 105                          * Usage count, *USE WRAPPER FUNCTION* when manual
 106                          * accounting. See page_ref.h
 107                          */
 108                         atomic_t _refcount;
 109                 };
 110         };
 111
 112         /*
 113          * Third double word block
 114          *
 115          * WARNING: bit 0 of the first word encode PageTail(). That means
 116          * the rest users of the storage space MUST NOT use the bit to
 117          * avoid collision and false-positive PageTail().
 118          */
 119         union {
 120                 struct list_head lru;   /* Pageout list, eg. active_list
 121                                          * protected by zone_lru_lock !
 122                                          * Can be used as a generic list
 123                                          * by the page owner.
 124                                          */
 125                 struct dev_pagemap *pgmap; /* ZONE_DEVICE pages are never on an
 126                                             * lru or handled by a slab
 127                                             * allocator, this points to the
 128                                             * hosting device page map.
 129                                             */
 130                 struct {                /* slub per cpu partial pages */
 131                         struct page *next;      /* Next partial slab */
 132 #ifdef CONFIG_64BIT
 133                         int pages;      /* Nr of partial slabs left */
 134                         int pobjects;   /* Approximate # of objects */
 135 #else
 136                         short int pages;
 137                         short int pobjects;
 138 #endif
 139                 };
 140
 141                 struct rcu_head rcu_head;       /* Used by SLAB
 142                                                  * when destroying via RCU
 143                                                  */
 144                 /* Tail pages of compound page */
 145                 struct {
 146                         unsigned long compound_head; /* If bit zero is set */
 147
 148                         /* First tail page only */
 149 #ifdef CONFIG_64BIT
 150                         /*
 151                          * On 64 bit system we have enough space in struct page
 152                          * to encode compound_dtor and compound_order with
 153                          * unsigned int. It can help compiler generate better or
 154                          * smaller code on some archtectures.
 155                          */
 156                         unsigned int compound_dtor;
 157                         unsigned int compound_order;
 158 #else
 159                         unsigned short int compound_dtor;
 160                         unsigned short int compound_order;
 161 #endif
 162                 };
 163
 164 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
 165                 struct {
 166                         unsigned long __pad;    /* do not overlay pmd_huge_pte
 167                                                  * with compound_head to avoid
 168                                                  * possible bit 0 collision.
 169                                                  */
 170                         pgtable_t pmd_huge_pte; /* protected by page->ptl */
 171                 };
 172 #endif
 173         };
 174
 175         /* Remainder is not double word aligned */
 176         union {
 177                 unsigned long private;          /* Mapping-private opaque data:
 178                                                  * usually used for buffer_heads
 179                                                  * if PagePrivate set; used for
 180                                                  * swp_entry_t if PageSwapCache;
 181                                                  * indicates order in the buddy
 182                                                  * system if PG_buddy is set.
 183                                                  */
 184 #if USE_SPLIT_PTE_PTLOCKS
 185 #if ALLOC_SPLIT_PTLOCKS
 186                 spinlock_t *ptl;
 187 #else
 188                 spinlock_t ptl;
 189 #endif
 190 #endif
 191                 struct kmem_cache *slab_cache;  /* SL[AU]B: Pointer to slab */
 192         };
 193
 194 #ifdef CONFIG_MEMCG
 195         struct mem_cgroup *mem_cgroup;
 196 #endif
 197
 198         /*
 199          * On machines where all RAM is mapped into kernel address space,
 200          * we can simply calculate the virtual address. On machines with
 201          * highmem some memory is mapped into kernel virtual memory
 202          * dynamically, so we need a place to store that address.
 203          * Note that this field could be 16 bits on x86 ... ;)
 204          *
 205          * Architectures with slow multiplication can define
 206          * WANT_PAGE_VIRTUAL in asm/page.h
 207          */
 208 #if defined(WANT_PAGE_VIRTUAL)
 209         void *virtual;                  /* Kernel virtual address (NULL if
 210                                            not kmapped, ie. highmem) */
 211 #endif /* WANT_PAGE_VIRTUAL */
 212
 213 #ifdef CONFIG_KMEMCHECK
 214         /*
 215          * kmemcheck wants to track the status of each byte in a page; this
 216          * is a pointer to such a status block. NULL if not tracked.
 217          */
 218         void *shadow;
 219 #endif
 220
 221 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
 222         int _last_cpupid;
 223 #endif
 224 }
 225 /*
 226  * The struct page can be forced to be double word aligned so that atomic ops
 227  * on double words work. The SLUB allocator can make use of such a feature.
 228  */
 229 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
 230         __aligned(2 * sizeof(unsigned long))
 231 #endif
 232 ;
 233
 234 struct page_frag {
 235         struct page *page;
 236 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
 237         __u32 offset;
 238         __u32 size;
 239 #else
 240         __u16 offset;
 241         __u16 size;
 242 #endif
 243 };
 244
 245 #define PAGE_FRAG_CACHE_MAX_SIZE        __ALIGN_MASK(32768, ~PAGE_MASK)
 246 #define PAGE_FRAG_CACHE_MAX_ORDER       get_order(PAGE_FRAG_CACHE_MAX_SIZE)
 247
 248 struct page_frag_cache {
 249         void * va;
 250 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
 251         __u16 offset;
 252         __u16 size;
 253 #else
 254         __u32 offset;
 255 #endif
 256         /* we maintain a pagecount bias, so that we dont dirty cache line
 257          * containing page->_refcount every time we allocate a fragment.
 258          */
 259         unsigned int            pagecnt_bias;
 260         bool pfmemalloc;
 261 };
 262
 263 typedef unsigned long vm_flags_t;
 264
 265 /*
 266  * A region containing a mapping of a non-memory backed file under NOMMU
 267  * conditions.  These are held in a global tree and are pinned by the VMAs that
 268  * map parts of them.
 269  */
 270 struct vm_region {
 271         struct rb_node  vm_rb;          /* link in global region tree */
 272         vm_flags_t      vm_flags;       /* VMA vm_flags */
 273         unsigned long   vm_start;       /* start address of region */
 274         unsigned long   vm_end;         /* region initialised to here */
 275         unsigned long   vm_top;         /* region allocated to here */
 276         unsigned long   vm_pgoff;       /* the offset in vm_file corresponding to vm_start */
 277         struct file     *vm_file;       /* the backing file or NULL */
 278
 279         int             vm_usage;       /* region usage count (access under nommu_region_sem) */
 280         bool            vm_icache_flushed : 1; /* true if the icache has been flushed for
 281                                                 * this region */
 282 };
 283
 284 #ifdef CONFIG_USERFAULTFD
 285 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
 286 struct vm_userfaultfd_ctx {
 287         struct userfaultfd_ctx *ctx;
 288 };
 289 #else /* CONFIG_USERFAULTFD */
 290 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
 291 struct vm_userfaultfd_ctx {};
 292 #endif /* CONFIG_USERFAULTFD */
 293
 294 /*
 295  * This struct defines a memory VMM memory area. There is one of these
 296  * per VM-area/task.  A VM area is any part of the process virtual memory
 297  * space that has a special rule for the page-fault handlers (ie a shared
 298  * library, the executable area etc).
 299  */
 300 struct vm_area_struct {
 301         /* The first cache line has the info for VMA tree walking. */
 302
 303         unsigned long vm_start;         /* Our start address within vm_mm. */
 304         unsigned long vm_end;           /* The first byte after our end address
 305                                            within vm_mm. */
 306
 307         /* linked list of VM areas per task, sorted by address */
 308         struct vm_area_struct *vm_next, *vm_prev;
 309
 310         struct rb_node vm_rb;
 311
 312         /*
 313          * Largest free memory gap in bytes to the left of this VMA.
 314          * Either between this VMA and vma->vm_prev, or between one of the
 315          * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
 316          * get_unmapped_area find a free area of the right size.
 317          */
 318         unsigned long rb_subtree_gap;
 319
 320         /* Second cache line starts here. */
 321
 322         struct mm_struct *vm_mm;        /* The address space we belong to. */
 323         pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
 324         unsigned long vm_flags;         /* Flags, see mm.h. */
 325
 326         /*
 327          * For areas with an address space and backing store,
 328          * linkage into the address_space->i_mmap interval tree.
 329          */
 330         struct {
 331                 struct rb_node rb;
 332                 unsigned long rb_subtree_last;
 333         } shared;
 334
 335         /*
 336          * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 337          * list, after a COW of one of the file pages.  A MAP_SHARED vma
 338          * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
 339          * or brk vma (with NULL file) can only be in an anon_vma list.
 340          */
 341         struct list_head anon_vma_chain; /* Serialized by mmap_sem &
 342                                           * page_table_lock */
 343         struct anon_vma *anon_vma;      /* Serialized by page_table_lock */
 344
 345         /* Function pointers to deal with this struct. */
 346         const struct vm_operations_struct *vm_ops;
 347
 348         /* Information about our backing store: */
 349         unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
 350                                            units */
 351         struct file * vm_file;          /* File we map to (can be NULL). */
 352         void * vm_private_data;         /* was vm_pte (shared mem) */
 353
 354 #ifndef CONFIG_MMU
 355         struct vm_region *vm_region;    /* NOMMU mapping region */
 356 #endif
 357 #ifdef CONFIG_NUMA
 358         struct mempolicy *vm_policy;    /* NUMA policy for the VMA */
 359 #endif
 360         struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
 361 };
 362
 363 struct core_thread {
 364         struct task_struct *task;
 365         struct core_thread *next;
 366 };
 367
 368 struct core_state {
 369         atomic_t nr_threads;
 370         struct core_thread dumper;
 371         struct completion startup;
 372 };
 373
 374 enum {
 375         MM_FILEPAGES,   /* Resident file mapping pages */
 376         MM_ANONPAGES,   /* Resident anonymous pages */
 377         MM_SWAPENTS,    /* Anonymous swap entries */
 378         MM_SHMEMPAGES,  /* Resident shared memory pages */
 379         NR_MM_COUNTERS
 380 };
 381
 382 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
 383 #define SPLIT_RSS_COUNTING
 384 /* per-thread cached information, */
 385 struct task_rss_stat {
 386         int events;     /* for synchronization threshold */
 387         int count[NR_MM_COUNTERS];
 388 };
 389 #endif /* USE_SPLIT_PTE_PTLOCKS */
 390
 391 struct mm_rss_stat {
 392         atomic_long_t count[NR_MM_COUNTERS];
 393 };
 394
 395 struct kioctx_table;
 396 struct mm_struct {
 397         struct vm_area_struct *mmap;            /* list of VMAs */
 398         struct rb_root mm_rb;
 399         u32 vmacache_seqnum;                   /* per-thread vmacache */
 400 #ifdef CONFIG_MMU
 401         unsigned long (*get_unmapped_area) (struct file *filp,
 402                                 unsigned long addr, unsigned long len,
 403                                 unsigned long pgoff, unsigned long flags);
 404 #endif
 405         unsigned long mmap_base;                /* base of mmap area */
 406         unsigned long mmap_legacy_base;         /* base of mmap area in bottom-up allocations */
 407         unsigned long task_size;                /* size of task vm space */
 408         unsigned long highest_vm_end;           /* highest vma end address */
 409         pgd_t * pgd;
 410
 411         /**
 412          * @mm_users: The number of users including userspace.
 413          *
 414          * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops
 415          * to 0 (i.e. when the task exits and there are no other temporary
 416          * reference holders), we also release a reference on @mm_count
 417          * (which may then free the &struct mm_struct if @mm_count also
 418          * drops to 0).
 419          */
 420         atomic_t mm_users;
 421
 422         /**
 423          * @mm_count: The number of references to &struct mm_struct
 424          * (@mm_users count as 1).
 425          *
 426          * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
 427          * &struct mm_struct is freed.
 428          */
 429         atomic_t mm_count;
 430
 431         atomic_long_t nr_ptes;                  /* PTE page table pages */
 432 #if CONFIG_PGTABLE_LEVELS > 2
 433         atomic_long_t nr_pmds;                  /* PMD page table pages */
 434 #endif
 435         int map_count;                          /* number of VMAs */
 436
 437         spinlock_t page_table_lock;             /* Protects page tables and some counters */
 438         struct rw_semaphore mmap_sem;
 439
 440         struct list_head mmlist;                /* List of maybe swapped mm's.  These are globally strung
 441                                                  * together off init_mm.mmlist, and are protected
 442                                                  * by mmlist_lock
 443                                                  */
 444
 445
 446         unsigned long hiwater_rss;      /* High-watermark of RSS usage */
 447         unsigned long hiwater_vm;       /* High-water virtual memory usage */
 448
 449         unsigned long total_vm;         /* Total pages mapped */
 450         unsigned long locked_vm;        /* Pages that have PG_mlocked set */
 451         unsigned long pinned_vm;        /* Refcount permanently increased */
 452         unsigned long data_vm;          /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
 453         unsigned long exec_vm;          /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
 454         unsigned long stack_vm;         /* VM_STACK */
 455         unsigned long def_flags;
 456         unsigned long start_code, end_code, start_data, end_data;
 457         unsigned long start_brk, brk, start_stack;
 458         unsigned long arg_start, arg_end, env_start, env_end;
 459
 460         unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
 461
 462         /*
 463          * Special counters, in some configurations protected by the
 464          * page_table_lock, in other configurations by being atomic.
 465          */
 466         struct mm_rss_stat rss_stat;
 467
 468         struct linux_binfmt *binfmt;
 469
 470         cpumask_var_t cpu_vm_mask_var;
 471
 472         /* Architecture-specific MM context */
 473         mm_context_t context;
 474
 475         unsigned long flags; /* Must use atomic bitops to access the bits */
 476
 477         struct core_state *core_state; /* coredumping support */
 478 #ifdef CONFIG_AIO
 479         spinlock_t                      ioctx_lock;
 480         struct kioctx_table __rcu       *ioctx_table;
 481 #endif
 482 #ifdef CONFIG_MEMCG
 483         /*
 484          * "owner" points to a task that is regarded as the canonical
 485          * user/owner of this mm. All of the following must be true in
 486          * order for it to be changed:
 487          *
 488          * current == mm->owner
 489          * current->mm != mm
 490          * new_owner->mm == mm
 491          * new_owner->alloc_lock is held
 492          */
 493         struct task_struct __rcu *owner;
 494 #endif
 495         struct user_namespace *user_ns;
 496
 497         /* store ref to file /proc/<pid>/exe symlink points to */
 498         struct file __rcu *exe_file;
 499 #ifdef CONFIG_MMU_NOTIFIER
 500         struct mmu_notifier_mm *mmu_notifier_mm;
 501 #endif
 502 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
 503         pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 504 #endif
 505 #ifdef CONFIG_CPUMASK_OFFSTACK
 506         struct cpumask cpumask_allocation;
 507 #endif
 508 #ifdef CONFIG_NUMA_BALANCING
 509         /*
 510          * numa_next_scan is the next time that the PTEs will be marked
 511          * pte_numa. NUMA hinting faults will gather statistics and migrate
 512          * pages to new nodes if necessary.
 513          */
 514         unsigned long numa_next_scan;
 515
 516         /* Restart point for scanning and setting pte_numa */
 517         unsigned long numa_scan_offset;
 518
 519         /* numa_scan_seq prevents two threads setting pte_numa */
 520         int numa_scan_seq;
 521 #endif
 522 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
 523         /*
 524          * An operation with batched TLB flushing is going on. Anything that
 525          * can move process memory needs to flush the TLB when moving a
 526          * PROT_NONE or PROT_NUMA mapped page.
 527          */
 528         bool tlb_flush_pending;
 529 #endif
 530         struct uprobes_state uprobes_state;
 531 #ifdef CONFIG_HUGETLB_PAGE
 532         atomic_long_t hugetlb_usage;
 533 #endif
 534         struct work_struct async_put_work;
 535 };
 536
 537 static inline void mm_init_cpumask(struct mm_struct *mm)
 538 {
 539 #ifdef CONFIG_CPUMASK_OFFSTACK
 540         mm->cpu_vm_mask_var = &mm->cpumask_allocation;
 541 #endif
 542         cpumask_clear(mm->cpu_vm_mask_var);
 543 }
 544
 545 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
 546 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 547 {
 548         return mm->cpu_vm_mask_var;
 549 }
 550
 551 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
 552 /*
 553  * Memory barriers to keep this state in sync are graciously provided by
 554  * the page table locks, outside of which no page table modifications happen.
 555  * The barriers below prevent the compiler from re-ordering the instructions
 556  * around the memory barriers that are already present in the code.
 557  */
 558 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
 559 {
 560         barrier();
 561         return mm->tlb_flush_pending;
 562 }
 563 static inline void set_tlb_flush_pending(struct mm_struct *mm)
 564 {
 565         mm->tlb_flush_pending = true;
 566
 567         /*
 568          * Guarantee that the tlb_flush_pending store does not leak into the
 569          * critical section updating the page tables
 570          */
 571         smp_mb__before_spinlock();
 572 }
 573 /* Clearing is done after a TLB flush, which also provides a barrier. */
 574 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
 575 {
 576         barrier();
 577         mm->tlb_flush_pending = false;
 578 }
 579 #else
 580 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
 581 {
 582         return false;
 583 }
 584 static inline void set_tlb_flush_pending(struct mm_struct *mm)
 585 {
 586 }
 587 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
 588 {
 589 }
 590 #endif
 591
 592 struct vm_fault;
 593
 594 struct vm_special_mapping {
 595         const char *name;       /* The name, e.g. "[vdso]". */
 596
 597         /*
 598          * If .fault is not provided, this points to a
 599          * NULL-terminated array of pages that back the special mapping.
 600          *
 601          * This must not be NULL unless .fault is provided.
 602          */
 603         struct page **pages;
 604
 605         /*
 606          * If non-NULL, then this is called to resolve page faults
 607          * on the special mapping.  If used, .pages is not checked.
 608          */
 609         int (*fault)(const struct vm_special_mapping *sm,
 610                      struct vm_area_struct *vma,
 611                      struct vm_fault *vmf);
 612
 613         int (*mremap)(const struct vm_special_mapping *sm,
 614                      struct vm_area_struct *new_vma);
 615 };
 616
 617 enum tlb_flush_reason {
 618         TLB_FLUSH_ON_TASK_SWITCH,
 619         TLB_REMOTE_SHOOTDOWN,
 620         TLB_LOCAL_SHOOTDOWN,
 621         TLB_LOCAL_MM_SHOOTDOWN,
 622         TLB_REMOTE_SEND_IPI,
 623         NR_TLB_FLUSH_REASONS,
 624 };
 625
 626  /*
 627   * A swap entry has to fit into a "unsigned long", as the entry is hidden
 628   * in the "index" field of the swapper address space.
 629   */
 630 typedef struct {
 631         unsigned long val;
 632 } swp_entry_t;
 633
 634 #endif /* _LINUX_MM_TYPES_H */