mm/internal.h

   1 /* internal.h: mm/ internal definitions
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #ifndef __MM_INTERNAL_H
  12 #define __MM_INTERNAL_H
  13
  14 #include <linux/fs.h>
  15 #include <linux/mm.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/tracepoint-defs.h>
  18
  19 /*
  20  * The set of flags that only affect watermark checking and reclaim
  21  * behaviour. This is used by the MM to obey the caller constraints
  22  * about IO, FS and watermark checking while ignoring placement
  23  * hints such as HIGHMEM usage.
  24  */
  25 #define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\
  26                         __GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\
  27                         __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC)
  28
  29 /* The GFP flags allowed during early boot */
  30 #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
  31
  32 /* Control allocation cpuset and node placement constraints */
  33 #define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
  34
  35 /* Do not use these with a slab allocator */
  36 #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
  37
  38 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  39                 unsigned long floor, unsigned long ceiling);
  40
  41 extern int __do_page_cache_readahead(struct address_space *mapping,
  42                 struct file *filp, pgoff_t offset, unsigned long nr_to_read,
  43                 unsigned long lookahead_size);
  44
  45 /*
  46  * Submit IO for the read-ahead request in file_ra_state.
  47  */
  48 static inline unsigned long ra_submit(struct file_ra_state *ra,
  49                 struct address_space *mapping, struct file *filp)
  50 {
  51         return __do_page_cache_readahead(mapping, filp,
  52                                         ra->start, ra->size, ra->async_size);
  53 }
  54
  55 /*
  56  * Turn a non-refcounted page (->_count == 0) into refcounted with
  57  * a count of one.
  58  */
  59 static inline void set_page_refcounted(struct page *page)
  60 {
  61         VM_BUG_ON_PAGE(PageTail(page), page);
  62         VM_BUG_ON_PAGE(page_ref_count(page), page);
  63         set_page_count(page, 1);
  64 }
  65
  66 extern unsigned long highest_memmap_pfn;
  67
  68 /*
  69  * in mm/vmscan.c:
  70  */
  71 extern int isolate_lru_page(struct page *page);
  72 extern void putback_lru_page(struct page *page);
  73 extern bool zone_reclaimable(struct zone *zone);
  74
  75 /*
  76  * in mm/rmap.c:
  77  */
  78 extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
  79
  80 /*
  81  * in mm/page_alloc.c
  82  */
  83
  84 /*
  85  * Structure for holding the mostly immutable allocation parameters passed
  86  * between functions involved in allocations, including the alloc_pages*
  87  * family of functions.
  88  *
  89  * nodemask, migratetype and high_zoneidx are initialized only once in
  90  * __alloc_pages_nodemask() and then never change.
  91  *
  92  * zonelist, preferred_zone and classzone_idx are set first in
  93  * __alloc_pages_nodemask() for the fast path, and might be later changed
  94  * in __alloc_pages_slowpath(). All other functions pass the whole strucure
  95  * by a const pointer.
  96  */
  97 struct alloc_context {
  98         struct zonelist *zonelist;
  99         nodemask_t *nodemask;
 100         struct zone *preferred_zone;
 101         int classzone_idx;
 102         int migratetype;
 103         enum zone_type high_zoneidx;
 104         bool spread_dirty_pages;
 105 };
 106
 107 /*
 108  * Locate the struct page for both the matching buddy in our
 109  * pair (buddy1) and the combined O(n+1) page they form (page).
 110  *
 111  * 1) Any buddy B1 will have an order O twin B2 which satisfies
 112  * the following equation:
 113  *     B2 = B1 ^ (1 << O)
 114  * For example, if the starting buddy (buddy2) is #8 its order
 115  * 1 buddy is #10:
 116  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 117  *
 118  * 2) Any buddy B will have an order O+1 parent P which
 119  * satisfies the following equation:
 120  *     P = B & ~(1 << O)
 121  *
 122  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
 123  */
 124 static inline unsigned long
 125 __find_buddy_index(unsigned long page_idx, unsigned int order)
 126 {
 127         return page_idx ^ (1 << order);
 128 }
 129
 130 extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
 131                                 unsigned long end_pfn, struct zone *zone);
 132
 133 static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
 134                                 unsigned long end_pfn, struct zone *zone)
 135 {
 136         if (zone->contiguous)
 137                 return pfn_to_page(start_pfn);
 138
 139         return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
 140 }
 141
 142 extern int __isolate_free_page(struct page *page, unsigned int order);
 143 extern void __free_pages_bootmem(struct page *page, unsigned long pfn,
 144                                         unsigned int order);
 145 extern void prep_compound_page(struct page *page, unsigned int order);
 146 extern int user_min_free_kbytes;
 147
 148 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 149
 150 /*
 151  * in mm/compaction.c
 152  */
 153 /*
 154  * compact_control is used to track pages being migrated and the free pages
 155  * they are being migrated to during memory compaction. The free_pfn starts
 156  * at the end of a zone and migrate_pfn begins at the start. Movable pages
 157  * are moved to the end of a zone during a compaction run and the run
 158  * completes when free_pfn <= migrate_pfn
 159  */
 160 struct compact_control {
 161         struct list_head freepages;     /* List of free pages to migrate to */
 162         struct list_head migratepages;  /* List of pages being migrated */
 163         unsigned long nr_freepages;     /* Number of isolated free pages */
 164         unsigned long nr_migratepages;  /* Number of pages to migrate */
 165         unsigned long free_pfn;         /* isolate_freepages search base */
 166         unsigned long migrate_pfn;      /* isolate_migratepages search base */
 167         unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
 168         enum migrate_mode mode;         /* Async or sync migration mode */
 169         bool ignore_skip_hint;          /* Scan blocks even if marked skip */
 170         bool direct_compaction;         /* False from kcompactd or /proc/... */
 171         int order;                      /* order a direct compactor needs */
 172         const gfp_t gfp_mask;           /* gfp mask of a direct compactor */
 173         const int alloc_flags;          /* alloc flags of a direct compactor */
 174         const int classzone_idx;        /* zone index of a direct compactor */
 175         struct zone *zone;
 176         int contended;                  /* Signal need_sched() or lock
 177                                          * contention detected during
 178                                          * compaction
 179                                          */
 180 };
 181
 182 unsigned long
 183 isolate_freepages_range(struct compact_control *cc,
 184                         unsigned long start_pfn, unsigned long end_pfn);
 185 unsigned long
 186 isolate_migratepages_range(struct compact_control *cc,
 187                            unsigned long low_pfn, unsigned long end_pfn);
 188 int find_suitable_fallback(struct free_area *area, unsigned int order,
 189                         int migratetype, bool only_stealable, bool *can_steal);
 190
 191 #endif
 192
 193 /*
 194  * This function returns the order of a free page in the buddy system. In
 195  * general, page_zone(page)->lock must be held by the caller to prevent the
 196  * page from being allocated in parallel and returning garbage as the order.
 197  * If a caller does not hold page_zone(page)->lock, it must guarantee that the
 198  * page cannot be allocated or merged in parallel. Alternatively, it must
 199  * handle invalid values gracefully, and use page_order_unsafe() below.
 200  */
 201 static inline unsigned int page_order(struct page *page)
 202 {
 203         /* PageBuddy() must be checked by the caller */
 204         return page_private(page);
 205 }
 206
 207 /*
 208  * Like page_order(), but for callers who cannot afford to hold the zone lock.
 209  * PageBuddy() should be checked first by the caller to minimize race window,
 210  * and invalid values must be handled gracefully.
 211  *
 212  * READ_ONCE is used so that if the caller assigns the result into a local
 213  * variable and e.g. tests it for valid range before using, the compiler cannot
 214  * decide to remove the variable and inline the page_private(page) multiple
 215  * times, potentially observing different values in the tests and the actual
 216  * use of the result.
 217  */
 218 #define page_order_unsafe(page)         READ_ONCE(page_private(page))
 219
 220 static inline bool is_cow_mapping(vm_flags_t flags)
 221 {
 222         return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 223 }
 224
 225 /*
 226  * These three helpers classifies VMAs for virtual memory accounting.
 227  */
 228
 229 /*
 230  * Executable code area - executable, not writable, not stack
 231  */
 232 static inline bool is_exec_mapping(vm_flags_t flags)
 233 {
 234         return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
 235 }
 236
 237 /*
 238  * Stack area - atomatically grows in one direction
 239  *
 240  * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
 241  * do_mmap() forbids all other combinations.
 242  */
 243 static inline bool is_stack_mapping(vm_flags_t flags)
 244 {
 245         return (flags & VM_STACK) == VM_STACK;
 246 }
 247
 248 /*
 249  * Data area - private, writable, not stack
 250  */
 251 static inline bool is_data_mapping(vm_flags_t flags)
 252 {
 253         return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
 254 }
 255
 256 /* mm/util.c */
 257 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 258                 struct vm_area_struct *prev, struct rb_node *rb_parent);
 259
 260 #ifdef CONFIG_MMU
 261 extern long populate_vma_page_range(struct vm_area_struct *vma,
 262                 unsigned long start, unsigned long end, int *nonblocking);
 263 extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 264                         unsigned long start, unsigned long end);
 265 static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 266 {
 267         munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 268 }
 269
 270 /*
 271  * must be called with vma's mmap_sem held for read or write, and page locked.
 272  */
 273 extern void mlock_vma_page(struct page *page);
 274 extern unsigned int munlock_vma_page(struct page *page);
 275
 276 /*
 277  * Clear the page's PageMlocked().  This can be useful in a situation where
 278  * we want to unconditionally remove a page from the pagecache -- e.g.,
 279  * on truncation or freeing.
 280  *
 281  * It is legal to call this function for any page, mlocked or not.
 282  * If called for a page that is still mapped by mlocked vmas, all we do
 283  * is revert to lazy LRU behaviour -- semantics are not broken.
 284  */
 285 extern void clear_page_mlock(struct page *page);
 286
 287 /*
 288  * mlock_migrate_page - called only from migrate_misplaced_transhuge_page()
 289  * (because that does not go through the full procedure of migration ptes):
 290  * to migrate the Mlocked page flag; update statistics.
 291  */
 292 static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 293 {
 294         if (TestClearPageMlocked(page)) {
 295                 int nr_pages = hpage_nr_pages(page);
 296
 297                 /* Holding pmd lock, no change in irq context: __mod is safe */
 298                 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 299                 SetPageMlocked(newpage);
 300                 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
 301         }
 302 }
 303
 304 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 305
 306 /*
 307  * At what user virtual address is page expected in @vma?
 308  */
 309 static inline unsigned long
 310 __vma_address(struct page *page, struct vm_area_struct *vma)
 311 {
 312         pgoff_t pgoff = page_to_pgoff(page);
 313         return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
 314 }
 315
 316 static inline unsigned long
 317 vma_address(struct page *page, struct vm_area_struct *vma)
 318 {
 319         unsigned long address = __vma_address(page, vma);
 320
 321         /* page should be within @vma mapping range */
 322         VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
 323
 324         return address;
 325 }
 326
 327 #else /* !CONFIG_MMU */
 328 static inline void clear_page_mlock(struct page *page) { }
 329 static inline void mlock_vma_page(struct page *page) { }
 330 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 331
 332 #endif /* !CONFIG_MMU */
 333
 334 /*
 335  * Return the mem_map entry representing the 'offset' subpage within
 336  * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 337  * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 338  */
 339 static inline struct page *mem_map_offset(struct page *base, int offset)
 340 {
 341         if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 342                 return nth_page(base, offset);
 343         return base + offset;
 344 }
 345
 346 /*
 347  * Iterator over all subpages within the maximally aligned gigantic
 348  * page 'base'.  Handle any discontiguity in the mem_map.
 349  */
 350 static inline struct page *mem_map_next(struct page *iter,
 351                                                 struct page *base, int offset)
 352 {
 353         if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 354                 unsigned long pfn = page_to_pfn(base) + offset;
 355                 if (!pfn_valid(pfn))
 356                         return NULL;
 357                 return pfn_to_page(pfn);
 358         }
 359         return iter + 1;
 360 }
 361
 362 /*
 363  * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 364  * so all functions starting at paging_init should be marked __init
 365  * in those cases. SPARSEMEM, however, allows for memory hotplug,
 366  * and alloc_bootmem_node is not used.
 367  */
 368 #ifdef CONFIG_SPARSEMEM
 369 #define __paginginit __meminit
 370 #else
 371 #define __paginginit __init
 372 #endif
 373
 374 /* Memory initialisation debug and verification */
 375 enum mminit_level {
 376         MMINIT_WARNING,
 377         MMINIT_VERIFY,
 378         MMINIT_TRACE
 379 };
 380
 381 #ifdef CONFIG_DEBUG_MEMORY_INIT
 382
 383 extern int mminit_loglevel;
 384
 385 #define mminit_dprintk(level, prefix, fmt, arg...) \
 386 do { \
 387         if (level < mminit_loglevel) { \
 388                 if (level <= MMINIT_WARNING) \
 389                         pr_warn("mminit::" prefix " " fmt, ##arg);      \
 390                 else \
 391                         printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
 392         } \
 393 } while (0)
 394
 395 extern void mminit_verify_pageflags_layout(void);
 396 extern void mminit_verify_zonelist(void);
 397 #else
 398
 399 static inline void mminit_dprintk(enum mminit_level level,
 400                                 const char *prefix, const char *fmt, ...)
 401 {
 402 }
 403
 404 static inline void mminit_verify_pageflags_layout(void)
 405 {
 406 }
 407
 408 static inline void mminit_verify_zonelist(void)
 409 {
 410 }
 411 #endif /* CONFIG_DEBUG_MEMORY_INIT */
 412
 413 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 414 #if defined(CONFIG_SPARSEMEM)
 415 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 416                                 unsigned long *end_pfn);
 417 #else
 418 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 419                                 unsigned long *end_pfn)
 420 {
 421 }
 422 #endif /* CONFIG_SPARSEMEM */
 423
 424 #define ZONE_RECLAIM_NOSCAN     -2
 425 #define ZONE_RECLAIM_FULL       -1
 426 #define ZONE_RECLAIM_SOME       0
 427 #define ZONE_RECLAIM_SUCCESS    1
 428
 429 extern int hwpoison_filter(struct page *p);
 430
 431 extern u32 hwpoison_filter_dev_major;
 432 extern u32 hwpoison_filter_dev_minor;
 433 extern u64 hwpoison_filter_flags_mask;
 434 extern u64 hwpoison_filter_flags_value;
 435 extern u64 hwpoison_filter_memcg;
 436 extern u32 hwpoison_filter_enable;
 437
 438 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
 439         unsigned long, unsigned long,
 440         unsigned long, unsigned long);
 441
 442 extern void set_pageblock_order(void);
 443 unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 444                                             struct list_head *page_list);
 445 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
 446 #define ALLOC_WMARK_MIN         WMARK_MIN
 447 #define ALLOC_WMARK_LOW         WMARK_LOW
 448 #define ALLOC_WMARK_HIGH        WMARK_HIGH
 449 #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 450
 451 /* Mask to get the watermark bits */
 452 #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 453
 454 #define ALLOC_HARDER            0x10 /* try to alloc harder */
 455 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 456 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 457 #define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 458 #define ALLOC_FAIR              0x100 /* fair zone allocation */
 459
 460 enum ttu_flags;
 461 struct tlbflush_unmap_batch;
 462
 463 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 464 void try_to_unmap_flush(void);
 465 void try_to_unmap_flush_dirty(void);
 466 #else
 467 static inline void try_to_unmap_flush(void)
 468 {
 469 }
 470 static inline void try_to_unmap_flush_dirty(void)
 471 {
 472 }
 473
 474 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
 475
 476 extern const struct trace_print_flags pageflag_names[];
 477 extern const struct trace_print_flags vmaflag_names[];
 478 extern const struct trace_print_flags gfpflag_names[];
 479
 480 #endif  /* __MM_INTERNAL_H */