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internal.h
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1 /* internal.h: mm/ internal definitions
2  *
3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells ([email protected])
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/mm.h>
15 
16 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
17  unsigned long floor, unsigned long ceiling);
18 
19 static inline void set_page_count(struct page *page, int v)
20 {
21  atomic_set(&page->_count, v);
22 }
23 
24 /*
25  * Turn a non-refcounted page (->_count == 0) into refcounted with
26  * a count of one.
27  */
28 static inline void set_page_refcounted(struct page *page)
29 {
30  VM_BUG_ON(PageTail(page));
31  VM_BUG_ON(atomic_read(&page->_count));
32  set_page_count(page, 1);
33 }
34 
35 static inline void __put_page(struct page *page)
36 {
37  atomic_dec(&page->_count);
38 }
39 
40 static inline void __get_page_tail_foll(struct page *page,
41  bool get_page_head)
42 {
43  /*
44  * If we're getting a tail page, the elevated page->_count is
45  * required only in the head page and we will elevate the head
46  * page->_count and tail page->_mapcount.
47  *
48  * We elevate page_tail->_mapcount for tail pages to force
49  * page_tail->_count to be zero at all times to avoid getting
50  * false positives from get_page_unless_zero() with
51  * speculative page access (like in
52  * page_cache_get_speculative()) on tail pages.
53  */
54  VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
55  VM_BUG_ON(atomic_read(&page->_count) != 0);
56  VM_BUG_ON(page_mapcount(page) < 0);
57  if (get_page_head)
58  atomic_inc(&page->first_page->_count);
59  atomic_inc(&page->_mapcount);
60 }
61 
62 /*
63  * This is meant to be called as the FOLL_GET operation of
64  * follow_page() and it must be called while holding the proper PT
65  * lock while the pte (or pmd_trans_huge) is still mapping the page.
66  */
67 static inline void get_page_foll(struct page *page)
68 {
69  if (unlikely(PageTail(page)))
70  /*
71  * This is safe only because
72  * __split_huge_page_refcount() can't run under
73  * get_page_foll() because we hold the proper PT lock.
74  */
75  __get_page_tail_foll(page, true);
76  else {
77  /*
78  * Getting a normal page or the head of a compound page
79  * requires to already have an elevated page->_count.
80  */
81  VM_BUG_ON(atomic_read(&page->_count) <= 0);
82  atomic_inc(&page->_count);
83  }
84 }
85 
86 extern unsigned long highest_memmap_pfn;
87 
88 /*
89  * in mm/vmscan.c:
90  */
91 extern int isolate_lru_page(struct page *page);
92 extern void putback_lru_page(struct page *page);
93 
94 /*
95  * in mm/page_alloc.c
96  */
97 extern void __free_pages_bootmem(struct page *page, unsigned int order);
98 extern void prep_compound_page(struct page *page, unsigned long order);
99 #ifdef CONFIG_MEMORY_FAILURE
100 extern bool is_free_buddy_page(struct page *page);
101 #endif
102 
103 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
104 
105 /*
106  * in mm/compaction.c
107  */
108 /*
109  * compact_control is used to track pages being migrated and the free pages
110  * they are being migrated to during memory compaction. The free_pfn starts
111  * at the end of a zone and migrate_pfn begins at the start. Movable pages
112  * are moved to the end of a zone during a compaction run and the run
113  * completes when free_pfn <= migrate_pfn
114  */
115 struct compact_control {
116  struct list_head freepages; /* List of free pages to migrate to */
117  struct list_head migratepages; /* List of pages being migrated */
118  unsigned long nr_freepages; /* Number of isolated free pages */
119  unsigned long nr_migratepages; /* Number of pages to migrate */
120  unsigned long free_pfn; /* isolate_freepages search base */
121  unsigned long migrate_pfn; /* isolate_migratepages search base */
122  bool sync; /* Synchronous migration */
123  bool ignore_skip_hint; /* Scan blocks even if marked skip */
124  bool finished_update_free; /* True when the zone cached pfns are
125  * no longer being updated
126  */
127  bool finished_update_migrate;
128 
129  int order; /* order a direct compactor needs */
130  int migratetype; /* MOVABLE, RECLAIMABLE etc */
131  struct zone *zone;
132  bool contended; /* True if a lock was contended */
133  struct page **page; /* Page captured of requested size */
134 };
135 
136 unsigned long
137 isolate_freepages_range(struct compact_control *cc,
138  unsigned long start_pfn, unsigned long end_pfn);
139 unsigned long
140 isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
141  unsigned long low_pfn, unsigned long end_pfn, bool unevictable);
142 
143 #endif
144 
145 /*
146  * function for dealing with page's order in buddy system.
147  * zone->lock is already acquired when we use these.
148  * So, we don't need atomic page->flags operations here.
149  */
150 static inline unsigned long page_order(struct page *page)
151 {
152  /* PageBuddy() must be checked by the caller */
153  return page_private(page);
154 }
155 
156 /* mm/util.c */
157 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
158  struct vm_area_struct *prev, struct rb_node *rb_parent);
159 
160 #ifdef CONFIG_MMU
161 extern long mlock_vma_pages_range(struct vm_area_struct *vma,
162  unsigned long start, unsigned long end);
163 extern void munlock_vma_pages_range(struct vm_area_struct *vma,
164  unsigned long start, unsigned long end);
165 static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
166 {
167  munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
168 }
169 
170 /*
171  * Called only in fault path, to determine if a new page is being
172  * mapped into a LOCKED vma. If it is, mark page as mlocked.
173  */
174 static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
175  struct page *page)
176 {
177  VM_BUG_ON(PageLRU(page));
178 
179  if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
180  return 0;
181 
182  if (!TestSetPageMlocked(page)) {
183  mod_zone_page_state(page_zone(page), NR_MLOCK,
184  hpage_nr_pages(page));
185  count_vm_event(UNEVICTABLE_PGMLOCKED);
186  }
187  return 1;
188 }
189 
190 /*
191  * must be called with vma's mmap_sem held for read or write, and page locked.
192  */
193 extern void mlock_vma_page(struct page *page);
194 extern void munlock_vma_page(struct page *page);
195 
196 /*
197  * Clear the page's PageMlocked(). This can be useful in a situation where
198  * we want to unconditionally remove a page from the pagecache -- e.g.,
199  * on truncation or freeing.
200  *
201  * It is legal to call this function for any page, mlocked or not.
202  * If called for a page that is still mapped by mlocked vmas, all we do
203  * is revert to lazy LRU behaviour -- semantics are not broken.
204  */
205 extern void clear_page_mlock(struct page *page);
206 
207 /*
208  * mlock_migrate_page - called only from migrate_page_copy() to
209  * migrate the Mlocked page flag; update statistics.
210  */
211 static inline void mlock_migrate_page(struct page *newpage, struct page *page)
212 {
213  if (TestClearPageMlocked(page)) {
214  unsigned long flags;
215 
216  local_irq_save(flags);
217  __dec_zone_page_state(page, NR_MLOCK);
218  SetPageMlocked(newpage);
219  __inc_zone_page_state(newpage, NR_MLOCK);
220  local_irq_restore(flags);
221  }
222 }
223 
224 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
225 extern unsigned long vma_address(struct page *page,
226  struct vm_area_struct *vma);
227 #endif
228 #else /* !CONFIG_MMU */
229 static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
230 {
231  return 0;
232 }
233 static inline void clear_page_mlock(struct page *page) { }
234 static inline void mlock_vma_page(struct page *page) { }
235 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
236 
237 #endif /* !CONFIG_MMU */
238 
239 /*
240  * Return the mem_map entry representing the 'offset' subpage within
241  * the maximally aligned gigantic page 'base'. Handle any discontiguity
242  * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
243  */
244 static inline struct page *mem_map_offset(struct page *base, int offset)
245 {
246  if (unlikely(offset >= MAX_ORDER_NR_PAGES))
247  return pfn_to_page(page_to_pfn(base) + offset);
248  return base + offset;
249 }
250 
251 /*
252  * Iterator over all subpages within the maximally aligned gigantic
253  * page 'base'. Handle any discontiguity in the mem_map.
254  */
255 static inline struct page *mem_map_next(struct page *iter,
256  struct page *base, int offset)
257 {
258  if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
259  unsigned long pfn = page_to_pfn(base) + offset;
260  if (!pfn_valid(pfn))
261  return NULL;
262  return pfn_to_page(pfn);
263  }
264  return iter + 1;
265 }
266 
267 /*
268  * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
269  * so all functions starting at paging_init should be marked __init
270  * in those cases. SPARSEMEM, however, allows for memory hotplug,
271  * and alloc_bootmem_node is not used.
272  */
273 #ifdef CONFIG_SPARSEMEM
274 #define __paginginit __meminit
275 #else
276 #define __paginginit __init
277 #endif
278 
279 /* Memory initialisation debug and verification */
284 };
285 
286 #ifdef CONFIG_DEBUG_MEMORY_INIT
287 
288 extern int mminit_loglevel;
289 
290 #define mminit_dprintk(level, prefix, fmt, arg...) \
291 do { \
292  if (level < mminit_loglevel) { \
293  printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
294  printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
295  } \
296 } while (0)
297 
298 extern void mminit_verify_pageflags_layout(void);
299 extern void mminit_verify_page_links(struct page *page,
300  enum zone_type zone, unsigned long nid, unsigned long pfn);
301 extern void mminit_verify_zonelist(void);
302 
303 #else
304 
305 static inline void mminit_dprintk(enum mminit_level level,
306  const char *prefix, const char *fmt, ...)
307 {
308 }
309 
310 static inline void mminit_verify_pageflags_layout(void)
311 {
312 }
313 
314 static inline void mminit_verify_page_links(struct page *page,
315  enum zone_type zone, unsigned long nid, unsigned long pfn)
316 {
317 }
318 
319 static inline void mminit_verify_zonelist(void)
320 {
321 }
322 #endif /* CONFIG_DEBUG_MEMORY_INIT */
323 
324 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
325 #if defined(CONFIG_SPARSEMEM)
326 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
327  unsigned long *end_pfn);
328 #else
329 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
330  unsigned long *end_pfn)
331 {
332 }
333 #endif /* CONFIG_SPARSEMEM */
334 
335 #define ZONE_RECLAIM_NOSCAN -2
336 #define ZONE_RECLAIM_FULL -1
337 #define ZONE_RECLAIM_SOME 0
338 #define ZONE_RECLAIM_SUCCESS 1
339 
340 extern int hwpoison_filter(struct page *p);
341 
348 
349 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
350  unsigned long, unsigned long,
351  unsigned long, unsigned long);
352 
353 extern void set_pageblock_order(void);
354 unsigned long reclaim_clean_pages_from_list(struct zone *zone,
355  struct list_head *page_list);
356 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
357 #define ALLOC_WMARK_MIN WMARK_MIN
358 #define ALLOC_WMARK_LOW WMARK_LOW
359 #define ALLOC_WMARK_HIGH WMARK_HIGH
360 #define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
361 
362 /* Mask to get the watermark bits */
363 #define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
364 
365 #define ALLOC_HARDER 0x10 /* try to alloc harder */
366 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
367 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
368 #define ALLOC_CMA 0x80 /* allow allocations from CMA areas */
369 
370 #endif /* __MM_INTERNAL_H */