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
  17 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  18                 unsigned long floor, unsigned long ceiling);
  19
  20 static inline void set_page_count(struct page *page, int v)
  21 {
  22         atomic_set(&page->_count, v);
  23 }
  24
  25 extern int __do_page_cache_readahead(struct address_space *mapping,
  26                 struct file *filp, pgoff_t offset, unsigned long nr_to_read,
  27                 unsigned long lookahead_size);
  28
  29 /*
  30  * Submit IO for the read-ahead request in file_ra_state.
  31  */
  32 static inline unsigned long ra_submit(struct file_ra_state *ra,
  33                 struct address_space *mapping, struct file *filp)
  34 {
  35         return __do_page_cache_readahead(mapping, filp,
  36                                         ra->start, ra->size, ra->async_size);
  37 }
  38
  39 /*
  40  * Turn a non-refcounted page (->_count == 0) into refcounted with
  41  * a count of one.
  42  */
  43 static inline void set_page_refcounted(struct page *page)
  44 {
  45         VM_BUG_ON_PAGE(PageTail(page), page);
  46         VM_BUG_ON_PAGE(atomic_read(&page->_count), page);
  47         set_page_count(page, 1);
  48 }
  49
  50 static inline void __get_page_tail_foll(struct page *page,
  51                                         bool get_page_head)
  52 {
  53         /*
  54          * If we're getting a tail page, the elevated page->_count is
  55          * required only in the head page and we will elevate the head
  56          * page->_count and tail page->_mapcount.
  57          *
  58          * We elevate page_tail->_mapcount for tail pages to force
  59          * page_tail->_count to be zero at all times to avoid getting
  60          * false positives from get_page_unless_zero() with
  61          * speculative page access (like in
  62          * page_cache_get_speculative()) on tail pages.
  63          */
  64         VM_BUG_ON_PAGE(atomic_read(&page->first_page->_count) <= 0, page);
  65         if (get_page_head)
  66                 atomic_inc(&page->first_page->_count);
  67         get_huge_page_tail(page);
  68 }
  69
  70 /*
  71  * This is meant to be called as the FOLL_GET operation of
  72  * follow_page() and it must be called while holding the proper PT
  73  * lock while the pte (or pmd_trans_huge) is still mapping the page.
  74  */
  75 static inline void get_page_foll(struct page *page)
  76 {
  77         if (unlikely(PageTail(page)))
  78                 /*
  79                  * This is safe only because
  80                  * __split_huge_page_refcount() can't run under
  81                  * get_page_foll() because we hold the proper PT lock.
  82                  */
  83                 __get_page_tail_foll(page, true);
  84         else {
  85                 /*
  86                  * Getting a normal page or the head of a compound page
  87                  * requires to already have an elevated page->_count.
  88                  */
  89                 VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);
  90                 atomic_inc(&page->_count);
  91         }
  92 }
  93
  94 extern unsigned long highest_memmap_pfn;
  95
  96 /*
  97  * in mm/vmscan.c:
  98  */
  99 extern int isolate_lru_page(struct page *page);
 100 extern void putback_lru_page(struct page *page);
 101 extern bool zone_reclaimable(struct zone *zone);
 102
 103 /*
 104  * in mm/rmap.c:
 105  */
 106 extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
 107
 108 /*
 109  * in mm/page_alloc.c
 110  */
 111
 112 /*
 113  * Locate the struct page for both the matching buddy in our
 114  * pair (buddy1) and the combined O(n+1) page they form (page).
 115  *
 116  * 1) Any buddy B1 will have an order O twin B2 which satisfies
 117  * the following equation:
 118  *     B2 = B1 ^ (1 << O)
 119  * For example, if the starting buddy (buddy2) is #8 its order
 120  * 1 buddy is #10:
 121  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 122  *
 123  * 2) Any buddy B will have an order O+1 parent P which
 124  * satisfies the following equation:
 125  *     P = B & ~(1 << O)
 126  *
 127  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
 128  */
 129 static inline unsigned long
 130 __find_buddy_index(unsigned long page_idx, unsigned int order)
 131 {
 132         return page_idx ^ (1 << order);
 133 }
 134
 135 extern int __isolate_free_page(struct page *page, unsigned int order);
 136 extern void __free_pages_bootmem(struct page *page, unsigned long pfn,
 137                                         unsigned int order);
 138 extern void prep_compound_page(struct page *page, unsigned int order);
 139 #ifdef CONFIG_MEMORY_FAILURE
 140 extern bool is_free_buddy_page(struct page *page);
 141 #endif
 142 extern int user_min_free_kbytes;
 143
 144 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 145
 146 /*
 147  * in mm/compaction.c
 148  */
 149 /*
 150  * compact_control is used to track pages being migrated and the free pages
 151  * they are being migrated to during memory compaction. The free_pfn starts
 152  * at the end of a zone and migrate_pfn begins at the start. Movable pages
 153  * are moved to the end of a zone during a compaction run and the run
 154  * completes when free_pfn <= migrate_pfn
 155  */
 156 struct compact_control {
 157         struct list_head freepages;     /* List of free pages to migrate to */
 158         struct list_head migratepages;  /* List of pages being migrated */
 159         unsigned long nr_freepages;     /* Number of isolated free pages */
 160         unsigned long nr_migratepages;  /* Number of pages to migrate */
 161         unsigned long free_pfn;         /* isolate_freepages search base */
 162         unsigned long migrate_pfn;      /* isolate_migratepages search base */
 163         enum migrate_mode mode;         /* Async or sync migration mode */
 164         bool ignore_skip_hint;          /* Scan blocks even if marked skip */
 165         bool finished_update_free;      /* True when the zone cached pfns are
 166                                          * no longer being updated
 167                                          */
 168         bool finished_update_migrate;
 169
 170         int order;                      /* order a direct compactor needs */
 171         const gfp_t gfp_mask;           /* gfp mask of a direct compactor */
 172         struct zone *zone;
 173         int contended;                  /* Signal need_sched() or lock
 174                                          * contention detected during
 175                                          * compaction
 176                                          */
 177 };
 178
 179 unsigned long
 180 isolate_freepages_range(struct compact_control *cc,
 181                         unsigned long start_pfn, unsigned long end_pfn);
 182 unsigned long
 183 isolate_migratepages_range(struct compact_control *cc,
 184                            unsigned long low_pfn, unsigned long end_pfn);
 185
 186 #endif
 187
 188 /*
 189  * This function returns the order of a free page in the buddy system. In
 190  * general, page_zone(page)->lock must be held by the caller to prevent the
 191  * page from being allocated in parallel and returning garbage as the order.
 192  * If a caller does not hold page_zone(page)->lock, it must guarantee that the
 193  * page cannot be allocated or merged in parallel. Alternatively, it must
 194  * handle invalid values gracefully, and use page_order_unsafe() below.
 195  */
 196 static inline unsigned int page_order(struct page *page)
 197 {
 198         /* PageBuddy() must be checked by the caller */
 199         return page_private(page);
 200 }
 201
 202 /*
 203  * Like page_order(), but for callers who cannot afford to hold the zone lock.
 204  * PageBuddy() should be checked first by the caller to minimize race window,
 205  * and invalid values must be handled gracefully.
 206  *
 207  * ACCESS_ONCE is used so that if the caller assigns the result into a local
 208  * variable and e.g. tests it for valid range before using, the compiler cannot
 209  * decide to remove the variable and inline the page_private(page) multiple
 210  * times, potentially observing different values in the tests and the actual
 211  * use of the result.
 212  */
 213 #define page_order_unsafe(page)         ACCESS_ONCE(page_private(page))
 214
 215 static inline bool is_cow_mapping(vm_flags_t flags)
 216 {
 217         return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 218 }
 219
 220 /* mm/util.c */
 221 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 222                 struct vm_area_struct *prev, struct rb_node *rb_parent);
 223
 224 #ifdef CONFIG_MMU
 225 extern long __mlock_vma_pages_range(struct vm_area_struct *vma,
 226                 unsigned long start, unsigned long end, int *nonblocking);
 227 extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 228                         unsigned long start, unsigned long end);
 229 static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 230 {
 231         munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 232 }
 233
 234 /*
 235  * must be called with vma's mmap_sem held for read or write, and page locked.
 236  */
 237 extern void mlock_vma_page(struct page *page);
 238 extern unsigned int munlock_vma_page(struct page *page);
 239
 240 /*
 241  * Clear the page's PageMlocked().  This can be useful in a situation where
 242  * we want to unconditionally remove a page from the pagecache -- e.g.,
 243  * on truncation or freeing.
 244  *
 245  * It is legal to call this function for any page, mlocked or not.
 246  * If called for a page that is still mapped by mlocked vmas, all we do
 247  * is revert to lazy LRU behaviour -- semantics are not broken.
 248  */
 249 extern void clear_page_mlock(struct page *page);
 250
 251 /*
 252  * mlock_migrate_page - called only from migrate_page_copy() to
 253  * migrate the Mlocked page flag; update statistics.
 254  */
 255 static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 256 {
 257         if (TestClearPageMlocked(page)) {
 258                 unsigned long flags;
 259                 int nr_pages = hpage_nr_pages(page);
 260
 261                 local_irq_save(flags);
 262                 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 263                 SetPageMlocked(newpage);
 264                 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
 265                 local_irq_restore(flags);
 266         }
 267 }
 268
 269 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 270
 271 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 272 extern unsigned long vma_address(struct page *page,
 273                                  struct vm_area_struct *vma);
 274 #endif
 275 #else /* !CONFIG_MMU */
 276 static inline void clear_page_mlock(struct page *page) { }
 277 static inline void mlock_vma_page(struct page *page) { }
 278 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 279
 280 #endif /* !CONFIG_MMU */
 281
 282 /*
 283  * Return the mem_map entry representing the 'offset' subpage within
 284  * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 285  * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 286  */
 287 static inline struct page *mem_map_offset(struct page *base, int offset)
 288 {
 289         if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 290                 return nth_page(base, offset);
 291         return base + offset;
 292 }
 293
 294 /*
 295  * Iterator over all subpages within the maximally aligned gigantic
 296  * page 'base'.  Handle any discontiguity in the mem_map.
 297  */
 298 static inline struct page *mem_map_next(struct page *iter,
 299                                                 struct page *base, int offset)
 300 {
 301         if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 302                 unsigned long pfn = page_to_pfn(base) + offset;
 303                 if (!pfn_valid(pfn))
 304                         return NULL;
 305                 return pfn_to_page(pfn);
 306         }
 307         return iter + 1;
 308 }
 309
 310 /*
 311  * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 312  * so all functions starting at paging_init should be marked __init
 313  * in those cases. SPARSEMEM, however, allows for memory hotplug,
 314  * and alloc_bootmem_node is not used.
 315  */
 316 #ifdef CONFIG_SPARSEMEM
 317 #define __paginginit __meminit
 318 #else
 319 #define __paginginit __init
 320 #endif
 321
 322 /* Memory initialisation debug and verification */
 323 enum mminit_level {
 324         MMINIT_WARNING,
 325         MMINIT_VERIFY,
 326         MMINIT_TRACE
 327 };
 328
 329 #ifdef CONFIG_DEBUG_MEMORY_INIT
 330
 331 extern int mminit_loglevel;
 332
 333 #define mminit_dprintk(level, prefix, fmt, arg...) \
 334 do { \
 335         if (level < mminit_loglevel) { \
 336                 printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
 337                 printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
 338         } \
 339 } while (0)
 340
 341 extern void mminit_verify_pageflags_layout(void);
 342 extern void mminit_verify_page_links(struct page *page,
 343                 enum zone_type zone, unsigned long nid, unsigned long pfn);
 344 extern void mminit_verify_zonelist(void);
 345
 346 #else
 347
 348 static inline void mminit_dprintk(enum mminit_level level,
 349                                 const char *prefix, const char *fmt, ...)
 350 {
 351 }
 352
 353 static inline void mminit_verify_pageflags_layout(void)
 354 {
 355 }
 356
 357 static inline void mminit_verify_page_links(struct page *page,
 358                 enum zone_type zone, unsigned long nid, unsigned long pfn)
 359 {
 360 }
 361
 362 static inline void mminit_verify_zonelist(void)
 363 {
 364 }
 365 #endif /* CONFIG_DEBUG_MEMORY_INIT */
 366
 367 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 368 #if defined(CONFIG_SPARSEMEM)
 369 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 370                                 unsigned long *end_pfn);
 371 #else
 372 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 373                                 unsigned long *end_pfn)
 374 {
 375 }
 376 #endif /* CONFIG_SPARSEMEM */
 377
 378 #define ZONE_RECLAIM_NOSCAN     -2
 379 #define ZONE_RECLAIM_FULL       -1
 380 #define ZONE_RECLAIM_SOME       0
 381 #define ZONE_RECLAIM_SUCCESS    1
 382
 383 extern int hwpoison_filter(struct page *p);
 384
 385 extern u32 hwpoison_filter_dev_major;
 386 extern u32 hwpoison_filter_dev_minor;
 387 extern u64 hwpoison_filter_flags_mask;
 388 extern u64 hwpoison_filter_flags_value;
 389 extern u64 hwpoison_filter_memcg;
 390 extern u32 hwpoison_filter_enable;
 391
 392 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
 393         unsigned long, unsigned long,
 394         unsigned long, unsigned long);
 395
 396 extern void set_pageblock_order(void);
 397 unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 398                                             struct list_head *page_list);
 399 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
 400 #define ALLOC_WMARK_MIN         WMARK_MIN
 401 #define ALLOC_WMARK_LOW         WMARK_LOW
 402 #define ALLOC_WMARK_HIGH        WMARK_HIGH
 403 #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 404
 405 /* Mask to get the watermark bits */
 406 #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 407
 408 #define ALLOC_HARDER            0x10 /* try to alloc harder */
 409 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 410 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 411 #define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 412 #define ALLOC_FAIR              0x100 /* fair zone allocation */
 413
 414 #endif  /* __MM_INTERNAL_H */