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 unsigned long last_migrated_pfn;/* Not yet flushed page being freed */ 186 enum migrate_mode mode; /* Async or sync migration mode */ 187 bool ignore_skip_hint; /* Scan blocks even if marked skip */ 188 int order; /* order a direct compactor needs */ 189 const gfp_t gfp_mask; /* gfp mask of a direct compactor */ 190 const int alloc_flags; /* alloc flags of a direct compactor */ 191 const int classzone_idx; /* zone index of a direct compactor */ 192 struct zone *zone; 193 int contended; /* Signal need_sched() or lock 194 * contention detected during 195 * compaction 196 */ 197 }; 198 199 unsigned long 200 isolate_freepages_range(struct compact_control *cc, 201 unsigned long start_pfn, unsigned long end_pfn); 202 unsigned long 203 isolate_migratepages_range(struct compact_control *cc, 204 unsigned long low_pfn, unsigned long end_pfn); 205 int find_suitable_fallback(struct free_area *area, unsigned int order, 206 int migratetype, bool only_stealable, bool *can_steal); 207 208 #endif 209 210 /* 211 * This function returns the order of a free page in the buddy system. In 212 * general, page_zone(page)->lock must be held by the caller to prevent the 213 * page from being allocated in parallel and returning garbage as the order. 214 * If a caller does not hold page_zone(page)->lock, it must guarantee that the 215 * page cannot be allocated or merged in parallel. Alternatively, it must 216 * handle invalid values gracefully, and use page_order_unsafe() below. 217 */ 218 static inline unsigned long page_order(struct page *page) 219 { 220 /* PageBuddy() must be checked by the caller */ 221 return page_private(page); 222 } 223 224 /* 225 * Like page_order(), but for callers who cannot afford to hold the zone lock. 226 * PageBuddy() should be checked first by the caller to minimize race window, 227 * and invalid values must be handled gracefully. 228 * 229 * READ_ONCE is used so that if the caller assigns the result into a local 230 * variable and e.g. tests it for valid range before using, the compiler cannot 231 * decide to remove the variable and inline the page_private(page) multiple 232 * times, potentially observing different values in the tests and the actual 233 * use of the result. 234 */ 235 #define page_order_unsafe(page) READ_ONCE(page_private(page)) 236 237 static inline bool is_cow_mapping(vm_flags_t flags) 238 { 239 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 240 } 241 242 /* mm/util.c */ 243 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, 244 struct vm_area_struct *prev, struct rb_node *rb_parent); 245 246 #ifdef CONFIG_MMU 247 extern long populate_vma_page_range(struct vm_area_struct *vma, 248 unsigned long start, unsigned long end, int *nonblocking); 249 extern void munlock_vma_pages_range(struct vm_area_struct *vma, 250 unsigned long start, unsigned long end); 251 static inline void munlock_vma_pages_all(struct vm_area_struct *vma) 252 { 253 munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end); 254 } 255 256 /* 257 * must be called with vma's mmap_sem held for read or write, and page locked. 258 */ 259 extern void mlock_vma_page(struct page *page); 260 extern unsigned int munlock_vma_page(struct page *page); 261 262 /* 263 * Clear the page's PageMlocked(). This can be useful in a situation where 264 * we want to unconditionally remove a page from the pagecache -- e.g., 265 * on truncation or freeing. 266 * 267 * It is legal to call this function for any page, mlocked or not. 268 * If called for a page that is still mapped by mlocked vmas, all we do 269 * is revert to lazy LRU behaviour -- semantics are not broken. 270 */ 271 extern void clear_page_mlock(struct page *page); 272 273 /* 274 * mlock_migrate_page - called only from migrate_page_copy() to 275 * migrate the Mlocked page flag; update statistics. 276 */ 277 static inline void mlock_migrate_page(struct page *newpage, struct page *page) 278 { 279 if (TestClearPageMlocked(page)) { 280 unsigned long flags; 281 int nr_pages = hpage_nr_pages(page); 282 283 local_irq_save(flags); 284 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); 285 SetPageMlocked(newpage); 286 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages); 287 local_irq_restore(flags); 288 } 289 } 290 291 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); 292 293 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 294 extern unsigned long vma_address(struct page *page, 295 struct vm_area_struct *vma); 296 #endif 297 #else /* !CONFIG_MMU */ 298 static inline void clear_page_mlock(struct page *page) { } 299 static inline void mlock_vma_page(struct page *page) { } 300 static inline void mlock_migrate_page(struct page *new, struct page *old) { } 301 302 #endif /* !CONFIG_MMU */ 303 304 /* 305 * Return the mem_map entry representing the 'offset' subpage within 306 * the maximally aligned gigantic page 'base'. Handle any discontiguity 307 * in the mem_map at MAX_ORDER_NR_PAGES boundaries. 308 */ 309 static inline struct page *mem_map_offset(struct page *base, int offset) 310 { 311 if (unlikely(offset >= MAX_ORDER_NR_PAGES)) 312 return nth_page(base, offset); 313 return base + offset; 314 } 315 316 /* 317 * Iterator over all subpages within the maximally aligned gigantic 318 * page 'base'. Handle any discontiguity in the mem_map. 319 */ 320 static inline struct page *mem_map_next(struct page *iter, 321 struct page *base, int offset) 322 { 323 if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) { 324 unsigned long pfn = page_to_pfn(base) + offset; 325 if (!pfn_valid(pfn)) 326 return NULL; 327 return pfn_to_page(pfn); 328 } 329 return iter + 1; 330 } 331 332 /* 333 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node, 334 * so all functions starting at paging_init should be marked __init 335 * in those cases. SPARSEMEM, however, allows for memory hotplug, 336 * and alloc_bootmem_node is not used. 337 */ 338 #ifdef CONFIG_SPARSEMEM 339 #define __paginginit __meminit 340 #else 341 #define __paginginit __init 342 #endif 343 344 /* Memory initialisation debug and verification */ 345 enum mminit_level { 346 MMINIT_WARNING, 347 MMINIT_VERIFY, 348 MMINIT_TRACE 349 }; 350 351 #ifdef CONFIG_DEBUG_MEMORY_INIT 352 353 extern int mminit_loglevel; 354 355 #define mminit_dprintk(level, prefix, fmt, arg...) \ 356 do { \ 357 if (level < mminit_loglevel) { \ 358 if (level <= MMINIT_WARNING) \ 359 printk(KERN_WARNING "mminit::" prefix " " fmt, ##arg); \ 360 else \ 361 printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \ 362 } \ 363 } while (0) 364 365 extern void mminit_verify_pageflags_layout(void); 366 extern void mminit_verify_zonelist(void); 367 #else 368 369 static inline void mminit_dprintk(enum mminit_level level, 370 const char *prefix, const char *fmt, ...) 371 { 372 } 373 374 static inline void mminit_verify_pageflags_layout(void) 375 { 376 } 377 378 static inline void mminit_verify_zonelist(void) 379 { 380 } 381 #endif /* CONFIG_DEBUG_MEMORY_INIT */ 382 383 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */ 384 #if defined(CONFIG_SPARSEMEM) 385 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn, 386 unsigned long *end_pfn); 387 #else 388 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn, 389 unsigned long *end_pfn) 390 { 391 } 392 #endif /* CONFIG_SPARSEMEM */ 393 394 #define ZONE_RECLAIM_NOSCAN -2 395 #define ZONE_RECLAIM_FULL -1 396 #define ZONE_RECLAIM_SOME 0 397 #define ZONE_RECLAIM_SUCCESS 1 398 399 extern int hwpoison_filter(struct page *p); 400 401 extern u32 hwpoison_filter_dev_major; 402 extern u32 hwpoison_filter_dev_minor; 403 extern u64 hwpoison_filter_flags_mask; 404 extern u64 hwpoison_filter_flags_value; 405 extern u64 hwpoison_filter_memcg; 406 extern u32 hwpoison_filter_enable; 407 408 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long, 409 unsigned long, unsigned long, 410 unsigned long, unsigned long); 411 412 extern void set_pageblock_order(void); 413 unsigned long reclaim_clean_pages_from_list(struct zone *zone, 414 struct list_head *page_list); 415 /* The ALLOC_WMARK bits are used as an index to zone->watermark */ 416 #define ALLOC_WMARK_MIN WMARK_MIN 417 #define ALLOC_WMARK_LOW WMARK_LOW 418 #define ALLOC_WMARK_HIGH WMARK_HIGH 419 #define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */ 420 421 /* Mask to get the watermark bits */ 422 #define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1) 423 424 #define ALLOC_HARDER 0x10 /* try to alloc harder */ 425 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */ 426 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */ 427 #define ALLOC_CMA 0x80 /* allow allocations from CMA areas */ 428 #define ALLOC_FAIR 0x100 /* fair zone allocation */ 429 430 enum ttu_flags; 431 struct tlbflush_unmap_batch; 432 433 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 434 void try_to_unmap_flush(void); 435 void try_to_unmap_flush_dirty(void); 436 #else 437 static inline void try_to_unmap_flush(void) 438 { 439 } 440 static inline void try_to_unmap_flush_dirty(void) 441 { 442 } 443 444 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ 445 #endif /* __MM_INTERNAL_H */ 446