Root/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/mm.h>
15
16void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
17        unsigned long floor, unsigned long ceiling);
18
19static 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 */
28static 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
35static inline void __put_page(struct page *page)
36{
37    atomic_dec(&page->_count);
38}
39
40static 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 */
67static 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
86extern unsigned long highest_memmap_pfn;
87
88/*
89 * in mm/vmscan.c:
90 */
91extern int isolate_lru_page(struct page *page);
92extern void putback_lru_page(struct page *page);
93
94/*
95 * in mm/page_alloc.c
96 */
97extern void __free_pages_bootmem(struct page *page, unsigned int order);
98extern void prep_compound_page(struct page *page, unsigned long order);
99#ifdef CONFIG_MEMORY_FAILURE
100extern 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 */
115struct 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 start_free_pfn; /* where we started the search */
122    unsigned long migrate_pfn; /* isolate_migratepages search base */
123    bool sync; /* Synchronous migration */
124    bool wrapped; /* Order > 0 compactions are
125                       incremental, once free_pfn
126                       and migrate_pfn meet, we restart
127                       from the top of the zone;
128                       remember we wrapped around. */
129
130    int order; /* order a direct compactor needs */
131    int migratetype; /* MOVABLE, RECLAIMABLE etc */
132    struct zone *zone;
133};
134
135unsigned long
136isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn);
137unsigned long
138isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
139               unsigned long low_pfn, unsigned long end_pfn);
140
141#endif
142
143/*
144 * function for dealing with page's order in buddy system.
145 * zone->lock is already acquired when we use these.
146 * So, we don't need atomic page->flags operations here.
147 */
148static inline unsigned long page_order(struct page *page)
149{
150    /* PageBuddy() must be checked by the caller */
151    return page_private(page);
152}
153
154/* mm/util.c */
155void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
156        struct vm_area_struct *prev, struct rb_node *rb_parent);
157
158#ifdef CONFIG_MMU
159extern long mlock_vma_pages_range(struct vm_area_struct *vma,
160            unsigned long start, unsigned long end);
161extern void munlock_vma_pages_range(struct vm_area_struct *vma,
162            unsigned long start, unsigned long end);
163static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
164{
165    munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
166}
167
168/*
169 * Called only in fault path via page_evictable() for a new page
170 * to determine if it's being mapped into a LOCKED vma.
171 * If so, mark page as mlocked.
172 */
173static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
174                    struct page *page)
175{
176    VM_BUG_ON(PageLRU(page));
177
178    if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
179        return 0;
180
181    if (!TestSetPageMlocked(page)) {
182        inc_zone_page_state(page, NR_MLOCK);
183        count_vm_event(UNEVICTABLE_PGMLOCKED);
184    }
185    return 1;
186}
187
188/*
189 * must be called with vma's mmap_sem held for read or write, and page locked.
190 */
191extern void mlock_vma_page(struct page *page);
192extern void munlock_vma_page(struct page *page);
193
194/*
195 * Clear the page's PageMlocked(). This can be useful in a situation where
196 * we want to unconditionally remove a page from the pagecache -- e.g.,
197 * on truncation or freeing.
198 *
199 * It is legal to call this function for any page, mlocked or not.
200 * If called for a page that is still mapped by mlocked vmas, all we do
201 * is revert to lazy LRU behaviour -- semantics are not broken.
202 */
203extern void __clear_page_mlock(struct page *page);
204static inline void clear_page_mlock(struct page *page)
205{
206    if (unlikely(TestClearPageMlocked(page)))
207        __clear_page_mlock(page);
208}
209
210/*
211 * mlock_migrate_page - called only from migrate_page_copy() to
212 * migrate the Mlocked page flag; update statistics.
213 */
214static inline void mlock_migrate_page(struct page *newpage, struct page *page)
215{
216    if (TestClearPageMlocked(page)) {
217        unsigned long flags;
218
219        local_irq_save(flags);
220        __dec_zone_page_state(page, NR_MLOCK);
221        SetPageMlocked(newpage);
222        __inc_zone_page_state(newpage, NR_MLOCK);
223        local_irq_restore(flags);
224    }
225}
226
227#ifdef CONFIG_TRANSPARENT_HUGEPAGE
228extern unsigned long vma_address(struct page *page,
229                 struct vm_area_struct *vma);
230#endif
231#else /* !CONFIG_MMU */
232static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
233{
234    return 0;
235}
236static inline void clear_page_mlock(struct page *page) { }
237static inline void mlock_vma_page(struct page *page) { }
238static inline void mlock_migrate_page(struct page *new, struct page *old) { }
239
240#endif /* !CONFIG_MMU */
241
242/*
243 * Return the mem_map entry representing the 'offset' subpage within
244 * the maximally aligned gigantic page 'base'. Handle any discontiguity
245 * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
246 */
247static inline struct page *mem_map_offset(struct page *base, int offset)
248{
249    if (unlikely(offset >= MAX_ORDER_NR_PAGES))
250        return pfn_to_page(page_to_pfn(base) + offset);
251    return base + offset;
252}
253
254/*
255 * Iterator over all subpages within the maximally aligned gigantic
256 * page 'base'. Handle any discontiguity in the mem_map.
257 */
258static inline struct page *mem_map_next(struct page *iter,
259                        struct page *base, int offset)
260{
261    if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
262        unsigned long pfn = page_to_pfn(base) + offset;
263        if (!pfn_valid(pfn))
264            return NULL;
265        return pfn_to_page(pfn);
266    }
267    return iter + 1;
268}
269
270/*
271 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
272 * so all functions starting at paging_init should be marked __init
273 * in those cases. SPARSEMEM, however, allows for memory hotplug,
274 * and alloc_bootmem_node is not used.
275 */
276#ifdef CONFIG_SPARSEMEM
277#define __paginginit __meminit
278#else
279#define __paginginit __init
280#endif
281
282/* Memory initialisation debug and verification */
283enum mminit_level {
284    MMINIT_WARNING,
285    MMINIT_VERIFY,
286    MMINIT_TRACE
287};
288
289#ifdef CONFIG_DEBUG_MEMORY_INIT
290
291extern int mminit_loglevel;
292
293#define mminit_dprintk(level, prefix, fmt, arg...) \
294do { \
295    if (level < mminit_loglevel) { \
296        printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
297        printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
298    } \
299} while (0)
300
301extern void mminit_verify_pageflags_layout(void);
302extern void mminit_verify_page_links(struct page *page,
303        enum zone_type zone, unsigned long nid, unsigned long pfn);
304extern void mminit_verify_zonelist(void);
305
306#else
307
308static inline void mminit_dprintk(enum mminit_level level,
309                const char *prefix, const char *fmt, ...)
310{
311}
312
313static inline void mminit_verify_pageflags_layout(void)
314{
315}
316
317static inline void mminit_verify_page_links(struct page *page,
318        enum zone_type zone, unsigned long nid, unsigned long pfn)
319{
320}
321
322static inline void mminit_verify_zonelist(void)
323{
324}
325#endif /* CONFIG_DEBUG_MEMORY_INIT */
326
327/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
328#if defined(CONFIG_SPARSEMEM)
329extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
330                unsigned long *end_pfn);
331#else
332static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
333                unsigned long *end_pfn)
334{
335}
336#endif /* CONFIG_SPARSEMEM */
337
338#define ZONE_RECLAIM_NOSCAN -2
339#define ZONE_RECLAIM_FULL -1
340#define ZONE_RECLAIM_SOME 0
341#define ZONE_RECLAIM_SUCCESS 1
342#endif
343
344extern int hwpoison_filter(struct page *p);
345
346extern u32 hwpoison_filter_dev_major;
347extern u32 hwpoison_filter_dev_minor;
348extern u64 hwpoison_filter_flags_mask;
349extern u64 hwpoison_filter_flags_value;
350extern u64 hwpoison_filter_memcg;
351extern u32 hwpoison_filter_enable;
352
353extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
354        unsigned long, unsigned long,
355        unsigned long, unsigned long);
356
357extern void set_pageblock_order(void);
358

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