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