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/page-debug-flags.h> 14 #include <linux/uprobes.h> 15 #include <linux/page-flags-layout.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 26 #define USE_SPLIT_PTE_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS) 27 #define USE_SPLIT_PMD_PTLOCKS (USE_SPLIT_PTE_PTLOCKS && \ 28 IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK)) 29 #define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8) 30 31 /* 32 * Each physical page in the system has a struct page associated with 33 * it to keep track of whatever it is we are using the page for at the 34 * moment. Note that we have no way to track which tasks are using 35 * a page, though if it is a pagecache page, rmap structures can tell us 36 * who is mapping it. 37 * 38 * The objects in struct page are organized in double word blocks in 39 * order to allows us to use atomic double word operations on portions 40 * of struct page. That is currently only used by slub but the arrangement 41 * allows the use of atomic double word operations on the flags/mapping 42 * and lru list pointers also. 43 */ 44 struct page { 45 /* First double word block */ 46 unsigned long flags; /* Atomic flags, some possibly 47 * updated asynchronously */ 48 union { 49 struct address_space *mapping; /* If low bit clear, points to 50 * inode address_space, or NULL. 51 * If page mapped as anonymous 52 * memory, low bit is set, and 53 * it points to anon_vma object: 54 * see PAGE_MAPPING_ANON below. 55 */ 56 void *s_mem; /* slab first object */ 57 }; 58 59 /* Second double word */ 60 struct { 61 union { 62 pgoff_t index; /* Our offset within mapping. */ 63 void *freelist; /* sl[aou]b first free object */ 64 bool pfmemalloc; /* If set by the page allocator, 65 * ALLOC_NO_WATERMARKS was set 66 * and the low watermark was not 67 * met implying that the system 68 * is under some pressure. The 69 * caller should try ensure 70 * this page is only used to 71 * free other pages. 72 */ 73 }; 74 75 union { 76 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ 77 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 78 /* Used for cmpxchg_double in slub */ 79 unsigned long counters; 80 #else 81 /* 82 * Keep _count separate from slub cmpxchg_double data. 83 * As the rest of the double word is protected by 84 * slab_lock but _count is not. 85 */ 86 unsigned counters; 87 #endif 88 89 struct { 90 91 union { 92 /* 93 * Count of ptes mapped in 94 * mms, to show when page is 95 * mapped & limit reverse map 96 * searches. 97 * 98 * Used also for tail pages 99 * refcounting instead of 100 * _count. Tail pages cannot 101 * be mapped and keeping the 102 * tail page _count zero at 103 * all times guarantees 104 * get_page_unless_zero() will 105 * never succeed on tail 106 * pages. 107 */ 108 atomic_t _mapcount; 109 110 struct { /* SLUB */ 111 unsigned inuse:16; 112 unsigned objects:15; 113 unsigned frozen:1; 114 }; 115 int units; /* SLOB */ 116 }; 117 atomic_t _count; /* Usage count, see below. */ 118 }; 119 unsigned int active; /* SLAB */ 120 }; 121 }; 122 123 /* Third double word block */ 124 union { 125 struct list_head lru; /* Pageout list, eg. active_list 126 * protected by zone->lru_lock ! 127 */ 128 struct { /* slub per cpu partial pages */ 129 struct page *next; /* Next partial slab */ 130 #ifdef CONFIG_64BIT 131 int pages; /* Nr of partial slabs left */ 132 int pobjects; /* Approximate # of objects */ 133 #else 134 short int pages; 135 short int pobjects; 136 #endif 137 }; 138 139 struct list_head list; /* slobs list of pages */ 140 struct slab *slab_page; /* slab fields */ 141 struct rcu_head rcu_head; /* Used by SLAB 142 * when destroying via RCU 143 */ 144 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS 145 pgtable_t pmd_huge_pte; /* protected by page->ptl */ 146 #endif 147 }; 148 149 /* Remainder is not double word aligned */ 150 union { 151 unsigned long private; /* Mapping-private opaque data: 152 * usually used for buffer_heads 153 * if PagePrivate set; used for 154 * swp_entry_t if PageSwapCache; 155 * indicates order in the buddy 156 * system if PG_buddy is set. 157 */ 158 #if USE_SPLIT_PTE_PTLOCKS 159 #if ALLOC_SPLIT_PTLOCKS 160 spinlock_t *ptl; 161 #else 162 spinlock_t ptl; 163 #endif 164 #endif 165 struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */ 166 struct page *first_page; /* Compound tail pages */ 167 }; 168 169 /* 170 * On machines where all RAM is mapped into kernel address space, 171 * we can simply calculate the virtual address. On machines with 172 * highmem some memory is mapped into kernel virtual memory 173 * dynamically, so we need a place to store that address. 174 * Note that this field could be 16 bits on x86 ... ;) 175 * 176 * Architectures with slow multiplication can define 177 * WANT_PAGE_VIRTUAL in asm/page.h 178 */ 179 #if defined(WANT_PAGE_VIRTUAL) 180 void *virtual; /* Kernel virtual address (NULL if 181 not kmapped, ie. highmem) */ 182 #endif /* WANT_PAGE_VIRTUAL */ 183 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS 184 unsigned long debug_flags; /* Use atomic bitops on this */ 185 #endif 186 187 #ifdef CONFIG_KMEMCHECK 188 /* 189 * kmemcheck wants to track the status of each byte in a page; this 190 * is a pointer to such a status block. NULL if not tracked. 191 */ 192 void *shadow; 193 #endif 194 195 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 196 int _last_cpupid; 197 #endif 198 } 199 /* 200 * The struct page can be forced to be double word aligned so that atomic ops 201 * on double words work. The SLUB allocator can make use of such a feature. 202 */ 203 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 204 __aligned(2 * sizeof(unsigned long)) 205 #endif 206 ; 207 208 struct page_frag { 209 struct page *page; 210 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536) 211 __u32 offset; 212 __u32 size; 213 #else 214 __u16 offset; 215 __u16 size; 216 #endif 217 }; 218 219 typedef unsigned long __nocast vm_flags_t; 220 221 /* 222 * A region containing a mapping of a non-memory backed file under NOMMU 223 * conditions. These are held in a global tree and are pinned by the VMAs that 224 * map parts of them. 225 */ 226 struct vm_region { 227 struct rb_node vm_rb; /* link in global region tree */ 228 vm_flags_t vm_flags; /* VMA vm_flags */ 229 unsigned long vm_start; /* start address of region */ 230 unsigned long vm_end; /* region initialised to here */ 231 unsigned long vm_top; /* region allocated to here */ 232 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 233 struct file *vm_file; /* the backing file or NULL */ 234 235 int vm_usage; /* region usage count (access under nommu_region_sem) */ 236 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 237 * this region */ 238 }; 239 240 /* 241 * This struct defines a memory VMM memory area. There is one of these 242 * per VM-area/task. A VM area is any part of the process virtual memory 243 * space that has a special rule for the page-fault handlers (ie a shared 244 * library, the executable area etc). 245 */ 246 struct vm_area_struct { 247 /* The first cache line has the info for VMA tree walking. */ 248 249 unsigned long vm_start; /* Our start address within vm_mm. */ 250 unsigned long vm_end; /* The first byte after our end address 251 within vm_mm. */ 252 253 /* linked list of VM areas per task, sorted by address */ 254 struct vm_area_struct *vm_next, *vm_prev; 255 256 struct rb_node vm_rb; 257 258 /* 259 * Largest free memory gap in bytes to the left of this VMA. 260 * Either between this VMA and vma->vm_prev, or between one of the 261 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps 262 * get_unmapped_area find a free area of the right size. 263 */ 264 unsigned long rb_subtree_gap; 265 266 /* Second cache line starts here. */ 267 268 struct mm_struct *vm_mm; /* The address space we belong to. */ 269 pgprot_t vm_page_prot; /* Access permissions of this VMA. */ 270 unsigned long vm_flags; /* Flags, see mm.h. */ 271 272 /* 273 * For areas with an address space and backing store, 274 * linkage into the address_space->i_mmap interval tree, or 275 * linkage of vma in the address_space->i_mmap_nonlinear list. 276 */ 277 union { 278 struct { 279 struct rb_node rb; 280 unsigned long rb_subtree_last; 281 } linear; 282 struct list_head nonlinear; 283 } shared; 284 285 /* 286 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 287 * list, after a COW of one of the file pages. A MAP_SHARED vma 288 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 289 * or brk vma (with NULL file) can only be in an anon_vma list. 290 */ 291 struct list_head anon_vma_chain; /* Serialized by mmap_sem & 292 * page_table_lock */ 293 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 294 295 /* Function pointers to deal with this struct. */ 296 const struct vm_operations_struct *vm_ops; 297 298 /* Information about our backing store: */ 299 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 300 units, *not* PAGE_CACHE_SIZE */ 301 struct file * vm_file; /* File we map to (can be NULL). */ 302 void * vm_private_data; /* was vm_pte (shared mem) */ 303 304 #ifndef CONFIG_MMU 305 struct vm_region *vm_region; /* NOMMU mapping region */ 306 #endif 307 #ifdef CONFIG_NUMA 308 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 309 #endif 310 }; 311 312 struct core_thread { 313 struct task_struct *task; 314 struct core_thread *next; 315 }; 316 317 struct core_state { 318 atomic_t nr_threads; 319 struct core_thread dumper; 320 struct completion startup; 321 }; 322 323 enum { 324 MM_FILEPAGES, 325 MM_ANONPAGES, 326 MM_SWAPENTS, 327 NR_MM_COUNTERS 328 }; 329 330 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU) 331 #define SPLIT_RSS_COUNTING 332 /* per-thread cached information, */ 333 struct task_rss_stat { 334 int events; /* for synchronization threshold */ 335 int count[NR_MM_COUNTERS]; 336 }; 337 #endif /* USE_SPLIT_PTE_PTLOCKS */ 338 339 struct mm_rss_stat { 340 atomic_long_t count[NR_MM_COUNTERS]; 341 }; 342 343 struct kioctx_table; 344 struct mm_struct { 345 struct vm_area_struct * mmap; /* list of VMAs */ 346 struct rb_root mm_rb; 347 struct vm_area_struct * mmap_cache; /* last find_vma result */ 348 #ifdef CONFIG_MMU 349 unsigned long (*get_unmapped_area) (struct file *filp, 350 unsigned long addr, unsigned long len, 351 unsigned long pgoff, unsigned long flags); 352 #endif 353 unsigned long mmap_base; /* base of mmap area */ 354 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ 355 unsigned long task_size; /* size of task vm space */ 356 unsigned long highest_vm_end; /* highest vma end address */ 357 pgd_t * pgd; 358 atomic_t mm_users; /* How many users with user space? */ 359 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */ 360 atomic_long_t nr_ptes; /* Page table pages */ 361 int map_count; /* number of VMAs */ 362 363 spinlock_t page_table_lock; /* Protects page tables and some counters */ 364 struct rw_semaphore mmap_sem; 365 366 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung 367 * together off init_mm.mmlist, and are protected 368 * by mmlist_lock 369 */ 370 371 372 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 373 unsigned long hiwater_vm; /* High-water virtual memory usage */ 374 375 unsigned long total_vm; /* Total pages mapped */ 376 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 377 unsigned long pinned_vm; /* Refcount permanently increased */ 378 unsigned long shared_vm; /* Shared pages (files) */ 379 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */ 380 unsigned long stack_vm; /* VM_GROWSUP/DOWN */ 381 unsigned long def_flags; 382 unsigned long start_code, end_code, start_data, end_data; 383 unsigned long start_brk, brk, start_stack; 384 unsigned long arg_start, arg_end, env_start, env_end; 385 386 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 387 388 /* 389 * Special counters, in some configurations protected by the 390 * page_table_lock, in other configurations by being atomic. 391 */ 392 struct mm_rss_stat rss_stat; 393 394 struct linux_binfmt *binfmt; 395 396 cpumask_var_t cpu_vm_mask_var; 397 398 /* Architecture-specific MM context */ 399 mm_context_t context; 400 401 unsigned long flags; /* Must use atomic bitops to access the bits */ 402 403 struct core_state *core_state; /* coredumping support */ 404 #ifdef CONFIG_AIO 405 spinlock_t ioctx_lock; 406 struct kioctx_table __rcu *ioctx_table; 407 #endif 408 #ifdef CONFIG_MM_OWNER 409 /* 410 * "owner" points to a task that is regarded as the canonical 411 * user/owner of this mm. All of the following must be true in 412 * order for it to be changed: 413 * 414 * current == mm->owner 415 * current->mm != mm 416 * new_owner->mm == mm 417 * new_owner->alloc_lock is held 418 */ 419 struct task_struct __rcu *owner; 420 #endif 421 422 /* store ref to file /proc/<pid>/exe symlink points to */ 423 struct file *exe_file; 424 #ifdef CONFIG_MMU_NOTIFIER 425 struct mmu_notifier_mm *mmu_notifier_mm; 426 #endif 427 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS 428 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 429 #endif 430 #ifdef CONFIG_CPUMASK_OFFSTACK 431 struct cpumask cpumask_allocation; 432 #endif 433 #ifdef CONFIG_NUMA_BALANCING 434 /* 435 * numa_next_scan is the next time that the PTEs will be marked 436 * pte_numa. NUMA hinting faults will gather statistics and migrate 437 * pages to new nodes if necessary. 438 */ 439 unsigned long numa_next_scan; 440 441 /* Restart point for scanning and setting pte_numa */ 442 unsigned long numa_scan_offset; 443 444 /* numa_scan_seq prevents two threads setting pte_numa */ 445 int numa_scan_seq; 446 #endif 447 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION) 448 /* 449 * An operation with batched TLB flushing is going on. Anything that 450 * can move process memory needs to flush the TLB when moving a 451 * PROT_NONE or PROT_NUMA mapped page. 452 */ 453 bool tlb_flush_pending; 454 #endif 455 struct uprobes_state uprobes_state; 456 }; 457 458 static inline void mm_init_cpumask(struct mm_struct *mm) 459 { 460 #ifdef CONFIG_CPUMASK_OFFSTACK 461 mm->cpu_vm_mask_var = &mm->cpumask_allocation; 462 #endif 463 } 464 465 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 466 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 467 { 468 return mm->cpu_vm_mask_var; 469 } 470 471 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION) 472 /* 473 * Memory barriers to keep this state in sync are graciously provided by 474 * the page table locks, outside of which no page table modifications happen. 475 * The barriers below prevent the compiler from re-ordering the instructions 476 * around the memory barriers that are already present in the code. 477 */ 478 static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 479 { 480 barrier(); 481 return mm->tlb_flush_pending; 482 } 483 static inline void set_tlb_flush_pending(struct mm_struct *mm) 484 { 485 mm->tlb_flush_pending = true; 486 487 /* 488 * Guarantee that the tlb_flush_pending store does not leak into the 489 * critical section updating the page tables 490 */ 491 smp_mb__before_spinlock(); 492 } 493 /* Clearing is done after a TLB flush, which also provides a barrier. */ 494 static inline void clear_tlb_flush_pending(struct mm_struct *mm) 495 { 496 barrier(); 497 mm->tlb_flush_pending = false; 498 } 499 #else 500 static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 501 { 502 return false; 503 } 504 static inline void set_tlb_flush_pending(struct mm_struct *mm) 505 { 506 } 507 static inline void clear_tlb_flush_pending(struct mm_struct *mm) 508 { 509 } 510 #endif 511 512 #endif /* _LINUX_MM_TYPES_H */ 513