linux/mm/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 (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 __get_page_tail_foll(struct page *page,
  36                                        bool get_page_head)
  37{
  38        /*
  39         * If we're getting a tail page, the elevated page->_count is
  40         * required only in the head page and we will elevate the head
  41         * page->_count and tail page->_mapcount.
  42         *
  43         * We elevate page_tail->_mapcount for tail pages to force
  44         * page_tail->_count to be zero at all times to avoid getting
  45         * false positives from get_page_unless_zero() with
  46         * speculative page access (like in
  47         * page_cache_get_speculative()) on tail pages.
  48         */
  49        VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
  50        VM_BUG_ON(atomic_read(&page->_count) != 0);
  51        VM_BUG_ON(page_mapcount(page) < 0);
  52        if (get_page_head)
  53                atomic_inc(&page->first_page->_count);
  54        atomic_inc(&page->_mapcount);
  55}
  56
  57/*
  58 * This is meant to be called as the FOLL_GET operation of
  59 * follow_page() and it must be called while holding the proper PT
  60 * lock while the pte (or pmd_trans_huge) is still mapping the page.
  61 */
  62static inline void get_page_foll(struct page *page)
  63{
  64        if (unlikely(PageTail(page)))
  65                /*
  66                 * This is safe only because
  67                 * __split_huge_page_refcount() can't run under
  68                 * get_page_foll() because we hold the proper PT lock.
  69                 */
  70                __get_page_tail_foll(page, true);
  71        else {
  72                /*
  73                 * Getting a normal page or the head of a compound page
  74                 * requires to already have an elevated page->_count.
  75                 */
  76                VM_BUG_ON(atomic_read(&page->_count) <= 0);
  77                atomic_inc(&page->_count);
  78        }
  79}
  80
  81extern unsigned long highest_memmap_pfn;
  82
  83/*
  84 * in mm/vmscan.c:
  85 */
  86extern int isolate_lru_page(struct page *page);
  87extern void putback_lru_page(struct page *page);
  88extern unsigned long zone_reclaimable_pages(struct zone *zone);
  89extern bool zone_reclaimable(struct zone *zone);
  90
  91/*
  92 * in mm/rmap.c:
  93 */
  94extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
  95
  96/*
  97 * in mm/page_alloc.c
  98 */
  99extern void __free_pages_bootmem(struct page *page, unsigned int order);
 100extern void prep_compound_page(struct page *page, unsigned long order);
 101#ifdef CONFIG_MEMORY_FAILURE
 102extern bool is_free_buddy_page(struct page *page);
 103#endif
 104
 105#if defined CONFIG_COMPACTION || defined CONFIG_CMA
 106
 107/*
 108 * in mm/compaction.c
 109 */
 110/*
 111 * compact_control is used to track pages being migrated and the free pages
 112 * they are being migrated to during memory compaction. The free_pfn starts
 113 * at the end of a zone and migrate_pfn begins at the start. Movable pages
 114 * are moved to the end of a zone during a compaction run and the run
 115 * completes when free_pfn <= migrate_pfn
 116 */
 117struct compact_control {
 118        struct list_head freepages;     /* List of free pages to migrate to */
 119        struct list_head migratepages;  /* List of pages being migrated */
 120        unsigned long nr_freepages;     /* Number of isolated free pages */
 121        unsigned long nr_migratepages;  /* Number of pages to migrate */
 122        unsigned long free_pfn;         /* isolate_freepages search base */
 123        unsigned long migrate_pfn;      /* isolate_migratepages search base */
 124        bool sync;                      /* Synchronous migration */
 125        bool ignore_skip_hint;          /* Scan blocks even if marked skip */
 126        bool finished_update_free;      /* True when the zone cached pfns are
 127                                         * no longer being updated
 128                                         */
 129        bool finished_update_migrate;
 130
 131        int order;                      /* order a direct compactor needs */
 132        int migratetype;                /* MOVABLE, RECLAIMABLE etc */
 133        struct zone *zone;
 134        bool contended;                 /* True if a lock was contended */
 135};
 136
 137unsigned long
 138isolate_freepages_range(struct compact_control *cc,
 139                        unsigned long start_pfn, unsigned long end_pfn);
 140unsigned long
 141isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 142        unsigned long low_pfn, unsigned long end_pfn, bool unevictable);
 143
 144#endif
 145
 146/*
 147 * function for dealing with page's order in buddy system.
 148 * zone->lock is already acquired when we use these.
 149 * So, we don't need atomic page->flags operations here.
 150 */
 151static inline unsigned long page_order(struct page *page)
 152{
 153        /* PageBuddy() must be checked by the caller */
 154        return page_private(page);
 155}
 156
 157/* mm/util.c */
 158void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 159                struct vm_area_struct *prev, struct rb_node *rb_parent);
 160
 161#ifdef CONFIG_MMU
 162extern long __mlock_vma_pages_range(struct vm_area_struct *vma,
 163                unsigned long start, unsigned long end, int *nonblocking);
 164extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 165                        unsigned long start, unsigned long end);
 166static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 167{
 168        munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 169}
 170
 171/*
 172 * Called only in fault path, to determine if a new page is being
 173 * mapped into a LOCKED vma.  If it is, mark page as mlocked.
 174 */
 175static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
 176                                    struct page *page)
 177{
 178        VM_BUG_ON(PageLRU(page));
 179
 180        if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
 181                return 0;
 182
 183        if (!TestSetPageMlocked(page)) {
 184                mod_zone_page_state(page_zone(page), NR_MLOCK,
 185                                    hpage_nr_pages(page));
 186                count_vm_event(UNEVICTABLE_PGMLOCKED);
 187        }
 188        return 1;
 189}
 190
 191/*
 192 * must be called with vma's mmap_sem held for read or write, and page locked.
 193 */
 194extern void mlock_vma_page(struct page *page);
 195extern unsigned int munlock_vma_page(struct page *page);
 196
 197/*
 198 * Clear the page's PageMlocked().  This can be useful in a situation where
 199 * we want to unconditionally remove a page from the pagecache -- e.g.,
 200 * on truncation or freeing.
 201 *
 202 * It is legal to call this function for any page, mlocked or not.
 203 * If called for a page that is still mapped by mlocked vmas, all we do
 204 * is revert to lazy LRU behaviour -- semantics are not broken.
 205 */
 206extern void clear_page_mlock(struct page *page);
 207
 208/*
 209 * mlock_migrate_page - called only from migrate_page_copy() to
 210 * migrate the Mlocked page flag; update statistics.
 211 */
 212static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 213{
 214        if (TestClearPageMlocked(page)) {
 215                unsigned long flags;
 216                int nr_pages = hpage_nr_pages(page);
 217
 218                local_irq_save(flags);
 219                __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 220                SetPageMlocked(newpage);
 221                __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
 222                local_irq_restore(flags);
 223        }
 224}
 225
 226extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 227
 228#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 229extern unsigned long vma_address(struct page *page,
 230                                 struct vm_area_struct *vma);
 231#endif
 232#else /* !CONFIG_MMU */
 233static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
 234{
 235        return 0;
 236}
 237static inline void clear_page_mlock(struct page *page) { }
 238static inline void mlock_vma_page(struct page *page) { }
 239static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 240
 241#endif /* !CONFIG_MMU */
 242
 243/*
 244 * Return the mem_map entry representing the 'offset' subpage within
 245 * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 246 * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 247 */
 248static inline struct page *mem_map_offset(struct page *base, int offset)
 249{
 250        if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 251                return pfn_to_page(page_to_pfn(base) + offset);
 252        return base + offset;
 253}
 254
 255/*
 256 * Iterator over all subpages within the maximally aligned gigantic
 257 * page 'base'.  Handle any discontiguity in the mem_map.
 258 */
 259static inline struct page *mem_map_next(struct page *iter,
 260                                                struct page *base, int offset)
 261{
 262        if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 263                unsigned long pfn = page_to_pfn(base) + offset;
 264                if (!pfn_valid(pfn))
 265                        return NULL;
 266                return pfn_to_page(pfn);
 267        }
 268        return iter + 1;
 269}
 270
 271/*
 272 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 273 * so all functions starting at paging_init should be marked __init
 274 * in those cases. SPARSEMEM, however, allows for memory hotplug,
 275 * and alloc_bootmem_node is not used.
 276 */
 277#ifdef CONFIG_SPARSEMEM
 278#define __paginginit __meminit
 279#else
 280#define __paginginit __init
 281#endif
 282
 283/* Memory initialisation debug and verification */
 284enum mminit_level {
 285        MMINIT_WARNING,
 286        MMINIT_VERIFY,
 287        MMINIT_TRACE
 288};
 289
 290#ifdef CONFIG_DEBUG_MEMORY_INIT
 291
 292extern int mminit_loglevel;
 293
 294#define mminit_dprintk(level, prefix, fmt, arg...) \
 295do { \
 296        if (level < mminit_loglevel) { \
 297                printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
 298                printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
 299        } \
 300} while (0)
 301
 302extern void mminit_verify_pageflags_layout(void);
 303extern void mminit_verify_page_links(struct page *page,
 304                enum zone_type zone, unsigned long nid, unsigned long pfn);
 305extern void mminit_verify_zonelist(void);
 306
 307#else
 308
 309static inline void mminit_dprintk(enum mminit_level level,
 310                                const char *prefix, const char *fmt, ...)
 311{
 312}
 313
 314static inline void mminit_verify_pageflags_layout(void)
 315{
 316}
 317
 318static inline void mminit_verify_page_links(struct page *page,
 319                enum zone_type zone, unsigned long nid, unsigned long pfn)
 320{
 321}
 322
 323static inline void mminit_verify_zonelist(void)
 324{
 325}
 326#endif /* CONFIG_DEBUG_MEMORY_INIT */
 327
 328/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 329#if defined(CONFIG_SPARSEMEM)
 330extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 331                                unsigned long *end_pfn);
 332#else
 333static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 334                                unsigned long *end_pfn)
 335{
 336}
 337#endif /* CONFIG_SPARSEMEM */
 338
 339#define ZONE_RECLAIM_NOSCAN     -2
 340#define ZONE_RECLAIM_FULL       -1
 341#define ZONE_RECLAIM_SOME       0
 342#define ZONE_RECLAIM_SUCCESS    1
 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);
 358unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 359                                            struct list_head *page_list);
 360/* The ALLOC_WMARK bits are used as an index to zone->watermark */
 361#define ALLOC_WMARK_MIN         WMARK_MIN
 362#define ALLOC_WMARK_LOW         WMARK_LOW
 363#define ALLOC_WMARK_HIGH        WMARK_HIGH
 364#define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 365
 366/* Mask to get the watermark bits */
 367#define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 368
 369#define ALLOC_HARDER            0x10 /* try to alloc harder */
 370#define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 371#define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 372#define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 373
 374#endif  /* __MM_INTERNAL_H */
 375
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