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Linux/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                         __GFP_ATOMIC)
 29 
 30 /* The GFP flags allowed during early boot */
 31 #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
 32 
 33 /* Control allocation cpuset and node placement constraints */
 34 #define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
 35 
 36 /* Do not use these with a slab allocator */
 37 #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
 38 
 39 void page_writeback_init(void);
 40 
 41 int do_swap_page(struct vm_fault *vmf);
 42 
 43 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
 44                 unsigned long floor, unsigned long ceiling);
 45 
 46 void unmap_page_range(struct mmu_gather *tlb,
 47                              struct vm_area_struct *vma,
 48                              unsigned long addr, unsigned long end,
 49                              struct zap_details *details);
 50 
 51 extern int __do_page_cache_readahead(struct address_space *mapping,
 52                 struct file *filp, pgoff_t offset, unsigned long nr_to_read,
 53                 unsigned long lookahead_size);
 54 
 55 /*
 56  * Submit IO for the read-ahead request in file_ra_state.
 57  */
 58 static inline unsigned long ra_submit(struct file_ra_state *ra,
 59                 struct address_space *mapping, struct file *filp)
 60 {
 61         return __do_page_cache_readahead(mapping, filp,
 62                                         ra->start, ra->size, ra->async_size);
 63 }
 64 
 65 /*
 66  * Turn a non-refcounted page (->_refcount == 0) into refcounted with
 67  * a count of one.
 68  */
 69 static inline void set_page_refcounted(struct page *page)
 70 {
 71         VM_BUG_ON_PAGE(PageTail(page), page);
 72         VM_BUG_ON_PAGE(page_ref_count(page), page);
 73         set_page_count(page, 1);
 74 }
 75 
 76 extern unsigned long highest_memmap_pfn;
 77 
 78 /*
 79  * in mm/vmscan.c:
 80  */
 81 extern int isolate_lru_page(struct page *page);
 82 extern void putback_lru_page(struct page *page);
 83 extern bool pgdat_reclaimable(struct pglist_data *pgdat);
 84 
 85 /*
 86  * in mm/rmap.c:
 87  */
 88 extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
 89 
 90 /*
 91  * in mm/page_alloc.c
 92  */
 93 
 94 /*
 95  * Structure for holding the mostly immutable allocation parameters passed
 96  * between functions involved in allocations, including the alloc_pages*
 97  * family of functions.
 98  *
 99  * nodemask, migratetype and high_zoneidx are initialized only once in
100  * __alloc_pages_nodemask() and then never change.
101  *
102  * zonelist, preferred_zone and classzone_idx are set first in
103  * __alloc_pages_nodemask() for the fast path, and might be later changed
104  * in __alloc_pages_slowpath(). All other functions pass the whole strucure
105  * by a const pointer.
106  */
107 struct alloc_context {
108         struct zonelist *zonelist;
109         nodemask_t *nodemask;
110         struct zoneref *preferred_zoneref;
111         int migratetype;
112         enum zone_type high_zoneidx;
113         bool spread_dirty_pages;
114 };
115 
116 #define ac_classzone_idx(ac) zonelist_zone_idx(ac->preferred_zoneref)
117 
118 /*
119  * Locate the struct page for both the matching buddy in our
120  * pair (buddy1) and the combined O(n+1) page they form (page).
121  *
122  * 1) Any buddy B1 will have an order O twin B2 which satisfies
123  * the following equation:
124  *     B2 = B1 ^ (1 << O)
125  * For example, if the starting buddy (buddy2) is #8 its order
126  * 1 buddy is #10:
127  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
128  *
129  * 2) Any buddy B will have an order O+1 parent P which
130  * satisfies the following equation:
131  *     P = B & ~(1 << O)
132  *
133  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
134  */
135 static inline unsigned long
136 __find_buddy_index(unsigned long page_idx, unsigned int order)
137 {
138         return page_idx ^ (1 << order);
139 }
140 
141 extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
142                                 unsigned long end_pfn, struct zone *zone);
143 
144 static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
145                                 unsigned long end_pfn, struct zone *zone)
146 {
147         if (zone->contiguous)
148                 return pfn_to_page(start_pfn);
149 
150         return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
151 }
152 
153 extern int __isolate_free_page(struct page *page, unsigned int order);
154 extern void __free_pages_bootmem(struct page *page, unsigned long pfn,
155                                         unsigned int order);
156 extern void prep_compound_page(struct page *page, unsigned int order);
157 extern void post_alloc_hook(struct page *page, unsigned int order,
158                                         gfp_t gfp_flags);
159 extern int user_min_free_kbytes;
160 
161 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
162 
163 /*
164  * in mm/compaction.c
165  */
166 /*
167  * compact_control is used to track pages being migrated and the free pages
168  * they are being migrated to during memory compaction. The free_pfn starts
169  * at the end of a zone and migrate_pfn begins at the start. Movable pages
170  * are moved to the end of a zone during a compaction run and the run
171  * completes when free_pfn <= migrate_pfn
172  */
173 struct compact_control {
174         struct list_head freepages;     /* List of free pages to migrate to */
175         struct list_head migratepages;  /* List of pages being migrated */
176         unsigned long nr_freepages;     /* Number of isolated free pages */
177         unsigned long nr_migratepages;  /* Number of pages to migrate */
178         unsigned long free_pfn;         /* isolate_freepages search base */
179         unsigned long migrate_pfn;      /* isolate_migratepages search base */
180         unsigned long last_migrated_pfn;/* Not yet flushed page being freed */
181         enum migrate_mode mode;         /* Async or sync migration mode */
182         bool ignore_skip_hint;          /* Scan blocks even if marked skip */
183         bool ignore_block_suitable;     /* Scan blocks considered unsuitable */
184         bool direct_compaction;         /* False from kcompactd or /proc/... */
185         bool whole_zone;                /* Whole zone should/has been scanned */
186         int order;                      /* order a direct compactor needs */
187         const gfp_t gfp_mask;           /* gfp mask of a direct compactor */
188         const unsigned int alloc_flags; /* alloc flags of a direct compactor */
189         const int classzone_idx;        /* zone index of a direct compactor */
190         struct zone *zone;
191         bool contended;                 /* Signal lock or sched contention */
192 };
193 
194 unsigned long
195 isolate_freepages_range(struct compact_control *cc,
196                         unsigned long start_pfn, unsigned long end_pfn);
197 unsigned long
198 isolate_migratepages_range(struct compact_control *cc,
199                            unsigned long low_pfn, unsigned long end_pfn);
200 int find_suitable_fallback(struct free_area *area, unsigned int order,
201                         int migratetype, bool only_stealable, bool *can_steal);
202 
203 #endif
204 
205 /*
206  * This function returns the order of a free page in the buddy system. In
207  * general, page_zone(page)->lock must be held by the caller to prevent the
208  * page from being allocated in parallel and returning garbage as the order.
209  * If a caller does not hold page_zone(page)->lock, it must guarantee that the
210  * page cannot be allocated or merged in parallel. Alternatively, it must
211  * handle invalid values gracefully, and use page_order_unsafe() below.
212  */
213 static inline unsigned int page_order(struct page *page)
214 {
215         /* PageBuddy() must be checked by the caller */
216         return page_private(page);
217 }
218 
219 /*
220  * Like page_order(), but for callers who cannot afford to hold the zone lock.
221  * PageBuddy() should be checked first by the caller to minimize race window,
222  * and invalid values must be handled gracefully.
223  *
224  * READ_ONCE is used so that if the caller assigns the result into a local
225  * variable and e.g. tests it for valid range before using, the compiler cannot
226  * decide to remove the variable and inline the page_private(page) multiple
227  * times, potentially observing different values in the tests and the actual
228  * use of the result.
229  */
230 #define page_order_unsafe(page)         READ_ONCE(page_private(page))
231 
232 static inline bool is_cow_mapping(vm_flags_t flags)
233 {
234         return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
235 }
236 
237 /*
238  * These three helpers classifies VMAs for virtual memory accounting.
239  */
240 
241 /*
242  * Executable code area - executable, not writable, not stack
243  */
244 static inline bool is_exec_mapping(vm_flags_t flags)
245 {
246         return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
247 }
248 
249 /*
250  * Stack area - atomatically grows in one direction
251  *
252  * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
253  * do_mmap() forbids all other combinations.
254  */
255 static inline bool is_stack_mapping(vm_flags_t flags)
256 {
257         return (flags & VM_STACK) == VM_STACK;
258 }
259 
260 /*
261  * Data area - private, writable, not stack
262  */
263 static inline bool is_data_mapping(vm_flags_t flags)
264 {
265         return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
266 }
267 
268 /* mm/util.c */
269 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
270                 struct vm_area_struct *prev, struct rb_node *rb_parent);
271 
272 #ifdef CONFIG_MMU
273 extern long populate_vma_page_range(struct vm_area_struct *vma,
274                 unsigned long start, unsigned long end, int *nonblocking);
275 extern void munlock_vma_pages_range(struct vm_area_struct *vma,
276                         unsigned long start, unsigned long end);
277 static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
278 {
279         munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
280 }
281 
282 /*
283  * must be called with vma's mmap_sem held for read or write, and page locked.
284  */
285 extern void mlock_vma_page(struct page *page);
286 extern unsigned int munlock_vma_page(struct page *page);
287 
288 /*
289  * Clear the page's PageMlocked().  This can be useful in a situation where
290  * we want to unconditionally remove a page from the pagecache -- e.g.,
291  * on truncation or freeing.
292  *
293  * It is legal to call this function for any page, mlocked or not.
294  * If called for a page that is still mapped by mlocked vmas, all we do
295  * is revert to lazy LRU behaviour -- semantics are not broken.
296  */
297 extern void clear_page_mlock(struct page *page);
298 
299 /*
300  * mlock_migrate_page - called only from migrate_misplaced_transhuge_page()
301  * (because that does not go through the full procedure of migration ptes):
302  * to migrate the Mlocked page flag; update statistics.
303  */
304 static inline void mlock_migrate_page(struct page *newpage, struct page *page)
305 {
306         if (TestClearPageMlocked(page)) {
307                 int nr_pages = hpage_nr_pages(page);
308 
309                 /* Holding pmd lock, no change in irq context: __mod is safe */
310                 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
311                 SetPageMlocked(newpage);
312                 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
313         }
314 }
315 
316 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
317 
318 /*
319  * At what user virtual address is page expected in @vma?
320  */
321 static inline unsigned long
322 __vma_address(struct page *page, struct vm_area_struct *vma)
323 {
324         pgoff_t pgoff = page_to_pgoff(page);
325         return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
326 }
327 
328 static inline unsigned long
329 vma_address(struct page *page, struct vm_area_struct *vma)
330 {
331         unsigned long address = __vma_address(page, vma);
332 
333         /* page should be within @vma mapping range */
334         VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
335 
336         return address;
337 }
338 
339 #else /* !CONFIG_MMU */
340 static inline void clear_page_mlock(struct page *page) { }
341 static inline void mlock_vma_page(struct page *page) { }
342 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
343 
344 #endif /* !CONFIG_MMU */
345 
346 /*
347  * Return the mem_map entry representing the 'offset' subpage within
348  * the maximally aligned gigantic page 'base'.  Handle any discontiguity
349  * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
350  */
351 static inline struct page *mem_map_offset(struct page *base, int offset)
352 {
353         if (unlikely(offset >= MAX_ORDER_NR_PAGES))
354                 return nth_page(base, offset);
355         return base + offset;
356 }
357 
358 /*
359  * Iterator over all subpages within the maximally aligned gigantic
360  * page 'base'.  Handle any discontiguity in the mem_map.
361  */
362 static inline struct page *mem_map_next(struct page *iter,
363                                                 struct page *base, int offset)
364 {
365         if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
366                 unsigned long pfn = page_to_pfn(base) + offset;
367                 if (!pfn_valid(pfn))
368                         return NULL;
369                 return pfn_to_page(pfn);
370         }
371         return iter + 1;
372 }
373 
374 /*
375  * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
376  * so all functions starting at paging_init should be marked __init
377  * in those cases. SPARSEMEM, however, allows for memory hotplug,
378  * and alloc_bootmem_node is not used.
379  */
380 #ifdef CONFIG_SPARSEMEM
381 #define __paginginit __meminit
382 #else
383 #define __paginginit __init
384 #endif
385 
386 /* Memory initialisation debug and verification */
387 enum mminit_level {
388         MMINIT_WARNING,
389         MMINIT_VERIFY,
390         MMINIT_TRACE
391 };
392 
393 #ifdef CONFIG_DEBUG_MEMORY_INIT
394 
395 extern int mminit_loglevel;
396 
397 #define mminit_dprintk(level, prefix, fmt, arg...) \
398 do { \
399         if (level < mminit_loglevel) { \
400                 if (level <= MMINIT_WARNING) \
401                         pr_warn("mminit::" prefix " " fmt, ##arg);      \
402                 else \
403                         printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
404         } \
405 } while (0)
406 
407 extern void mminit_verify_pageflags_layout(void);
408 extern void mminit_verify_zonelist(void);
409 #else
410 
411 static inline void mminit_dprintk(enum mminit_level level,
412                                 const char *prefix, const char *fmt, ...)
413 {
414 }
415 
416 static inline void mminit_verify_pageflags_layout(void)
417 {
418 }
419 
420 static inline void mminit_verify_zonelist(void)
421 {
422 }
423 #endif /* CONFIG_DEBUG_MEMORY_INIT */
424 
425 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
426 #if defined(CONFIG_SPARSEMEM)
427 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
428                                 unsigned long *end_pfn);
429 #else
430 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
431                                 unsigned long *end_pfn)
432 {
433 }
434 #endif /* CONFIG_SPARSEMEM */
435 
436 #define NODE_RECLAIM_NOSCAN     -2
437 #define NODE_RECLAIM_FULL       -1
438 #define NODE_RECLAIM_SOME       0
439 #define NODE_RECLAIM_SUCCESS    1
440 
441 extern int hwpoison_filter(struct page *p);
442 
443 extern u32 hwpoison_filter_dev_major;
444 extern u32 hwpoison_filter_dev_minor;
445 extern u64 hwpoison_filter_flags_mask;
446 extern u64 hwpoison_filter_flags_value;
447 extern u64 hwpoison_filter_memcg;
448 extern u32 hwpoison_filter_enable;
449 
450 extern unsigned long  __must_check vm_mmap_pgoff(struct file *, unsigned long,
451         unsigned long, unsigned long,
452         unsigned long, unsigned long);
453 
454 extern void set_pageblock_order(void);
455 unsigned long reclaim_clean_pages_from_list(struct zone *zone,
456                                             struct list_head *page_list);
457 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
458 #define ALLOC_WMARK_MIN         WMARK_MIN
459 #define ALLOC_WMARK_LOW         WMARK_LOW
460 #define ALLOC_WMARK_HIGH        WMARK_HIGH
461 #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
462 
463 /* Mask to get the watermark bits */
464 #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
465 
466 #define ALLOC_HARDER            0x10 /* try to alloc harder */
467 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
468 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
469 #define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
470 
471 enum ttu_flags;
472 struct tlbflush_unmap_batch;
473 
474 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
475 void try_to_unmap_flush(void);
476 void try_to_unmap_flush_dirty(void);
477 #else
478 static inline void try_to_unmap_flush(void)
479 {
480 }
481 static inline void try_to_unmap_flush_dirty(void)
482 {
483 }
484 
485 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
486 
487 extern const struct trace_print_flags pageflag_names[];
488 extern const struct trace_print_flags vmaflag_names[];
489 extern const struct trace_print_flags gfpflag_names[];
490 
491 #endif  /* __MM_INTERNAL_H */
492 

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