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);
  88
  89/*
  90 * in mm/rmap.c:
  91 */
  92extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
  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 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};
 134
 135unsigned long
 136isolate_freepages_range(struct compact_control *cc,
 137                        unsigned long start_pfn, unsigned long end_pfn);
 138unsigned long
 139isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 140        unsigned long low_pfn, unsigned long end_pfn, bool unevictable);
 141
 142#endif
 143
 144/*
 145 * function for dealing with page's order in buddy system.
 146 * zone->lock is already acquired when we use these.
 147 * So, we don't need atomic page->flags operations here.
 148 */
 149static inline unsigned long page_order(struct page *page)
 150{
 151        /* PageBuddy() must be checked by the caller */
 152        return page_private(page);
 153}
 154
 155/* mm/util.c */
 156void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 157                struct vm_area_struct *prev, struct rb_node *rb_parent);
 158
 159#ifdef CONFIG_MMU
 160extern long __mlock_vma_pages_range(struct vm_area_struct *vma,
 161                unsigned long start, unsigned long end, int *nonblocking);
 162extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 163                        unsigned long start, unsigned long end);
 164static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 165{
 166        munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 167}
 168
 169/*
 170 * Called only in fault path, to determine if a new page is being
 171 * mapped into a LOCKED vma.  If it is, 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                mod_zone_page_state(page_zone(page), NR_MLOCK,
 183                                    hpage_nr_pages(page));
 184                count_vm_event(UNEVICTABLE_PGMLOCKED);
 185        }
 186        return 1;
 187}
 188
 189/*
 190 * must be called with vma's mmap_sem held for read or write, and page locked.
 191 */
 192extern void mlock_vma_page(struct page *page);
 193extern unsigned int munlock_vma_page(struct page *page);
 194
 195/*
 196 * Clear the page's PageMlocked().  This can be useful in a situation where
 197 * we want to unconditionally remove a page from the pagecache -- e.g.,
 198 * on truncation or freeing.
 199 *
 200 * It is legal to call this function for any page, mlocked or not.
 201 * If called for a page that is still mapped by mlocked vmas, all we do
 202 * is revert to lazy LRU behaviour -- semantics are not broken.
 203 */
 204extern void clear_page_mlock(struct page *page);
 205
 206/*
 207 * mlock_migrate_page - called only from migrate_page_copy() to
 208 * migrate the Mlocked page flag; update statistics.
 209 */
 210static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 211{
 212        if (TestClearPageMlocked(page)) {
 213                unsigned long flags;
 214                int nr_pages = hpage_nr_pages(page);
 215
 216                local_irq_save(flags);
 217                __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 218                SetPageMlocked(newpage);
 219                __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
 220                local_irq_restore(flags);
 221        }
 222}
 223
 224extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 225
 226#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 227extern unsigned long vma_address(struct page *page,
 228                                 struct vm_area_struct *vma);
 229#endif
 230#else /* !CONFIG_MMU */
 231static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
 232{
 233        return 0;
 234}
 235static inline void clear_page_mlock(struct page *page) { }
 236static inline void mlock_vma_page(struct page *page) { }
 237static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 238
 239#endif /* !CONFIG_MMU */
 240
 241/*
 242 * Return the mem_map entry representing the 'offset' subpage within
 243 * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 244 * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 245 */
 246static inline struct page *mem_map_offset(struct page *base, int offset)
 247{
 248        if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 249                return pfn_to_page(page_to_pfn(base) + offset);
 250        return base + offset;
 251}
 252
 253/*
 254 * Iterator over all subpages within the maximally aligned gigantic
 255 * page 'base'.  Handle any discontiguity in the mem_map.
 256 */
 257static inline struct page *mem_map_next(struct page *iter,
 258                                                struct page *base, int offset)
 259{
 260        if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 261                unsigned long pfn = page_to_pfn(base) + offset;
 262                if (!pfn_valid(pfn))
 263                        return NULL;
 264                return pfn_to_page(pfn);
 265        }
 266        return iter + 1;
 267}
 268
 269/*
 270 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 271 * so all functions starting at paging_init should be marked __init
 272 * in those cases. SPARSEMEM, however, allows for memory hotplug,
 273 * and alloc_bootmem_node is not used.
 274 */
 275#ifdef CONFIG_SPARSEMEM
 276#define __paginginit __meminit
 277#else
 278#define __paginginit __init
 279#endif
 280
 281/* Memory initialisation debug and verification */
 282enum mminit_level {
 283        MMINIT_WARNING,
 284        MMINIT_VERIFY,
 285        MMINIT_TRACE
 286};
 287
 288#ifdef CONFIG_DEBUG_MEMORY_INIT
 289
 290extern int mminit_loglevel;
 291
 292#define mminit_dprintk(level, prefix, fmt, arg...) \
 293do { \
 294        if (level < mminit_loglevel) { \
 295                printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
 296                printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
 297        } \
 298} while (0)
 299
 300extern void mminit_verify_pageflags_layout(void);
 301extern void mminit_verify_page_links(struct page *page,
 302                enum zone_type zone, unsigned long nid, unsigned long pfn);
 303extern void mminit_verify_zonelist(void);
 304
 305#else
 306
 307static inline void mminit_dprintk(enum mminit_level level,
 308                                const char *prefix, const char *fmt, ...)
 309{
 310}
 311
 312static inline void mminit_verify_pageflags_layout(void)
 313{
 314}
 315
 316static inline void mminit_verify_page_links(struct page *page,
 317                enum zone_type zone, unsigned long nid, unsigned long pfn)
 318{
 319}
 320
 321static inline void mminit_verify_zonelist(void)
 322{
 323}
 324#endif /* CONFIG_DEBUG_MEMORY_INIT */
 325
 326/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 327#if defined(CONFIG_SPARSEMEM)
 328extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 329                                unsigned long *end_pfn);
 330#else
 331static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 332                                unsigned long *end_pfn)
 333{
 334}
 335#endif /* CONFIG_SPARSEMEM */
 336
 337#define ZONE_RECLAIM_NOSCAN     -2
 338#define ZONE_RECLAIM_FULL       -1
 339#define ZONE_RECLAIM_SOME       0
 340#define ZONE_RECLAIM_SUCCESS    1
 341
 342extern int hwpoison_filter(struct page *p);
 343
 344extern u32 hwpoison_filter_dev_major;
 345extern u32 hwpoison_filter_dev_minor;
 346extern u64 hwpoison_filter_flags_mask;
 347extern u64 hwpoison_filter_flags_value;
 348extern u64 hwpoison_filter_memcg;
 349extern u32 hwpoison_filter_enable;
 350
 351extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
 352        unsigned long, unsigned long,
 353        unsigned long, unsigned long);
 354
 355extern void set_pageblock_order(void);
 356unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 357                                            struct list_head *page_list);
 358/* The ALLOC_WMARK bits are used as an index to zone->watermark */
 359#define ALLOC_WMARK_MIN         WMARK_MIN
 360#define ALLOC_WMARK_LOW         WMARK_LOW
 361#define ALLOC_WMARK_HIGH        WMARK_HIGH
 362#define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 363
 364/* Mask to get the watermark bits */
 365#define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 366
 367#define ALLOC_HARDER            0x10 /* try to alloc harder */
 368#define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 369#define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 370#define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 371
 372#endif  /* __MM_INTERNAL_H */
 373
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