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 * Structure for holding the mostly immutable allocation parameters passed 114 * between functions involved in allocations, including the alloc_pages* 115 * family of functions. 116 * 117 * nodemask, migratetype and high_zoneidx are initialized only once in 118 * __alloc_pages_nodemask() and then never change. 119 * 120 * zonelist, preferred_zone and classzone_idx are set first in 121 * __alloc_pages_nodemask() for the fast path, and might be later changed 122 * in __alloc_pages_slowpath(). All other functions pass the whole strucure 123 * by a const pointer. 124 */ 125 struct alloc_context { 126 struct zonelist *zonelist; 127 nodemask_t *nodemask; 128 struct zone *preferred_zone; 129 int classzone_idx; 130 int migratetype; 131 enum zone_type high_zoneidx; 132 }; 133 134 /* 135 * Locate the struct page for both the matching buddy in our 136 * pair (buddy1) and the combined O(n+1) page they form (page). 137 * 138 * 1) Any buddy B1 will have an order O twin B2 which satisfies 139 * the following equation: 140 * B2 = B1 ^ (1 << O) 141 * For example, if the starting buddy (buddy2) is #8 its order 142 * 1 buddy is #10: 143 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10 144 * 145 * 2) Any buddy B will have an order O+1 parent P which 146 * satisfies the following equation: 147 * P = B & ~(1 << O) 148 * 149 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER 150 */ 151 static inline unsigned long 152 __find_buddy_index(unsigned long page_idx, unsigned int order) 153 { 154 return page_idx ^ (1 << order); 155 } 156 157 extern int __isolate_free_page(struct page *page, unsigned int order); 158 extern void __free_pages_bootmem(struct page *page, unsigned long pfn, 159 unsigned int order); 160 extern void prep_compound_page(struct page *page, unsigned long order); 161 #ifdef CONFIG_MEMORY_FAILURE 162 extern bool is_free_buddy_page(struct page *page); 163 #endif 164 extern int user_min_free_kbytes; 165 166 #if defined CONFIG_COMPACTION || defined CONFIG_CMA 167 168 /* 169 * in mm/compaction.c 170 */ 171 /* 172 * compact_control is used to track pages being migrated and the free pages 173 * they are being migrated to during memory compaction. The free_pfn starts 174 * at the end of a zone and migrate_pfn begins at the start. Movable pages 175 * are moved to the end of a zone during a compaction run and the run 176 * completes when free_pfn <= migrate_pfn 177 */ 178 struct compact_control { 179 struct list_head freepages; /* List of free pages to migrate to */ 180 struct list_head migratepages; /* List of pages being migrated */ 181 unsigned long nr_freepages; /* Number of isolated free pages */ 182 unsigned long nr_migratepages; /* Number of pages to migrate */ 183 unsigned long free_pfn; /* isolate_freepages search base */ 184 unsigned long migrate_pfn; /* isolate_migratepages search base */ 185 enum migrate_mode mode; /* Async or sync migration mode */ 186 bool ignore_skip_hint; /* Scan blocks even if marked skip */ 187 int order; /* order a direct compactor needs */ 188 const gfp_t gfp_mask; /* gfp mask of a direct compactor */ 189 const int alloc_flags; /* alloc flags of a direct compactor */ 190 const int classzone_idx; /* zone index of a direct compactor */ 191 struct zone *zone; 192 int contended; /* Signal need_sched() or lock 193 * contention detected during 194 * compaction 195 */ 196 }; 197 198 unsigned long 199 isolate_freepages_range(struct compact_control *cc, 200 unsigned long start_pfn, unsigned long end_pfn); 201 unsigned long 202 isolate_migratepages_range(struct compact_control *cc, 203 unsigned long low_pfn, unsigned long end_pfn); 204 int find_suitable_fallback(struct free_area *area, unsigned int order, 205 int migratetype, bool only_stealable, bool *can_steal); 206 207 #endif 208 209 /* 210 * This function returns the order of a free page in the buddy system. In 211 * general, page_zone(page)->lock must be held by the caller to prevent the 212 * page from being allocated in parallel and returning garbage as the order. 213 * If a caller does not hold page_zone(page)->lock, it must guarantee that the 214 * page cannot be allocated or merged in parallel. Alternatively, it must 215 * handle invalid values gracefully, and use page_order_unsafe() below. 216 */ 217 static inline unsigned long page_order(struct page *page) 218 { 219 /* PageBuddy() must be checked by the caller */ 220 return page_private(page); 221 } 222 223 /* 224 * Like page_order(), but for callers who cannot afford to hold the zone lock. 225 * PageBuddy() should be checked first by the caller to minimize race window, 226 * and invalid values must be handled gracefully. 227 * 228 * READ_ONCE is used so that if the caller assigns the result into a local 229 * variable and e.g. tests it for valid range before using, the compiler cannot 230 * decide to remove the variable and inline the page_private(page) multiple 231 * times, potentially observing different values in the tests and the actual 232 * use of the result. 233 */ 234 #define page_order_unsafe(page) READ_ONCE(page_private(page)) 235 236 static inline bool is_cow_mapping(vm_flags_t flags) 237 { 238 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 239 } 240 241 /* mm/util.c */ 242 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, 243 struct vm_area_struct *prev, struct rb_node *rb_parent); 244 245 #ifdef CONFIG_MMU 246 extern long populate_vma_page_range(struct vm_area_struct *vma, 247 unsigned long start, unsigned long end, int *nonblocking); 248 extern void munlock_vma_pages_range(struct vm_area_struct *vma, 249 unsigned long start, unsigned long end); 250 static inline void munlock_vma_pages_all(struct vm_area_struct *vma) 251 { 252 munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end); 253 } 254 255 /* 256 * must be called with vma's mmap_sem held for read or write, and page locked. 257 */ 258 extern void mlock_vma_page(struct page *page); 259 extern unsigned int munlock_vma_page(struct page *page); 260 261 /* 262 * Clear the page's PageMlocked(). This can be useful in a situation where 263 * we want to unconditionally remove a page from the pagecache -- e.g., 264 * on truncation or freeing. 265 * 266 * It is legal to call this function for any page, mlocked or not. 267 * If called for a page that is still mapped by mlocked vmas, all we do 268 * is revert to lazy LRU behaviour -- semantics are not broken. 269 */ 270 extern void clear_page_mlock(struct page *page); 271 272 /* 273 * mlock_migrate_page - called only from migrate_page_copy() to 274 * migrate the Mlocked page flag; update statistics. 275 */ 276 static inline void mlock_migrate_page(struct page *newpage, struct page *page) 277 { 278 if (TestClearPageMlocked(page)) { 279 unsigned long flags; 280 int nr_pages = hpage_nr_pages(page); 281 282 local_irq_save(flags); 283 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); 284 SetPageMlocked(newpage); 285 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages); 286 local_irq_restore(flags); 287 } 288 } 289 290 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); 291 292 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 293 extern unsigned long vma_address(struct page *page, 294 struct vm_area_struct *vma); 295 #endif 296 #else /* !CONFIG_MMU */ 297 static inline void clear_page_mlock(struct page *page) { } 298 static inline void mlock_vma_page(struct page *page) { } 299 static inline void mlock_migrate_page(struct page *new, struct page *old) { } 300 301 #endif /* !CONFIG_MMU */ 302 303 /* 304 * Return the mem_map entry representing the 'offset' subpage within 305 * the maximally aligned gigantic page 'base'. Handle any discontiguity 306 * in the mem_map at MAX_ORDER_NR_PAGES boundaries. 307 */ 308 static inline struct page *mem_map_offset(struct page *base, int offset) 309 { 310 if (unlikely(offset >= MAX_ORDER_NR_PAGES)) 311 return nth_page(base, offset); 312 return base + offset; 313 } 314 315 /* 316 * Iterator over all subpages within the maximally aligned gigantic 317 * page 'base'. Handle any discontiguity in the mem_map. 318 */ 319 static inline struct page *mem_map_next(struct page *iter, 320 struct page *base, int offset) 321 { 322 if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) { 323 unsigned long pfn = page_to_pfn(base) + offset; 324 if (!pfn_valid(pfn)) 325 return NULL; 326 return pfn_to_page(pfn); 327 } 328 return iter + 1; 329 } 330 331 /* 332 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node, 333 * so all functions starting at paging_init should be marked __init 334 * in those cases. SPARSEMEM, however, allows for memory hotplug, 335 * and alloc_bootmem_node is not used. 336 */ 337 #ifdef CONFIG_SPARSEMEM 338 #define __paginginit __meminit 339 #else 340 #define __paginginit __init 341 #endif 342 343 /* Memory initialisation debug and verification */ 344 enum mminit_level { 345 MMINIT_WARNING, 346 MMINIT_VERIFY, 347 MMINIT_TRACE 348 }; 349 350 #ifdef CONFIG_DEBUG_MEMORY_INIT 351 352 extern int mminit_loglevel; 353 354 #define mminit_dprintk(level, prefix, fmt, arg...) \ 355 do { \ 356 if (level < mminit_loglevel) { \ 357 if (level <= MMINIT_WARNING) \ 358 printk(KERN_WARNING "mminit::" prefix " " fmt, ##arg); \ 359 else \ 360 printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \ 361 } \ 362 } while (0) 363 364 extern void mminit_verify_pageflags_layout(void); 365 extern void mminit_verify_zonelist(void); 366 #else 367 368 static inline void mminit_dprintk(enum mminit_level level, 369 const char *prefix, const char *fmt, ...) 370 { 371 } 372 373 static inline void mminit_verify_pageflags_layout(void) 374 { 375 } 376 377 static inline void mminit_verify_zonelist(void) 378 { 379 } 380 #endif /* CONFIG_DEBUG_MEMORY_INIT */ 381 382 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */ 383 #if defined(CONFIG_SPARSEMEM) 384 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn, 385 unsigned long *end_pfn); 386 #else 387 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn, 388 unsigned long *end_pfn) 389 { 390 } 391 #endif /* CONFIG_SPARSEMEM */ 392 393 #define ZONE_RECLAIM_NOSCAN -2 394 #define ZONE_RECLAIM_FULL -1 395 #define ZONE_RECLAIM_SOME 0 396 #define ZONE_RECLAIM_SUCCESS 1 397 398 extern int hwpoison_filter(struct page *p); 399 400 extern u32 hwpoison_filter_dev_major; 401 extern u32 hwpoison_filter_dev_minor; 402 extern u64 hwpoison_filter_flags_mask; 403 extern u64 hwpoison_filter_flags_value; 404 extern u64 hwpoison_filter_memcg; 405 extern u32 hwpoison_filter_enable; 406 407 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long, 408 unsigned long, unsigned long, 409 unsigned long, unsigned long); 410 411 extern void set_pageblock_order(void); 412 unsigned long reclaim_clean_pages_from_list(struct zone *zone, 413 struct list_head *page_list); 414 /* The ALLOC_WMARK bits are used as an index to zone->watermark */ 415 #define ALLOC_WMARK_MIN WMARK_MIN 416 #define ALLOC_WMARK_LOW WMARK_LOW 417 #define ALLOC_WMARK_HIGH WMARK_HIGH 418 #define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */ 419 420 /* Mask to get the watermark bits */ 421 #define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1) 422 423 #define ALLOC_HARDER 0x10 /* try to alloc harder */ 424 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */ 425 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */ 426 #define ALLOC_CMA 0x80 /* allow allocations from CMA areas */ 427 #define ALLOC_FAIR 0x100 /* fair zone allocation */ 428 429 #endif /* __MM_INTERNAL_H */ 430