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 __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/rmap.c:
  96 */
  97extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
  98
  99/*
 100 * in mm/page_alloc.c
 101 */
 102extern void __free_pages_bootmem(struct page *page, unsigned int order);
 103extern void prep_compound_page(struct page *page, unsigned long order);
 104#ifdef CONFIG_MEMORY_FAILURE
 105extern bool is_free_buddy_page(struct page *page);
 106#endif
 107
 108#if defined CONFIG_COMPACTION || defined CONFIG_CMA
 109
 110/*
 111 * in mm/compaction.c
 112 */
 113/*
 114 * compact_control is used to track pages being migrated and the free pages
 115 * they are being migrated to during memory compaction. The free_pfn starts
 116 * at the end of a zone and migrate_pfn begins at the start. Movable pages
 117 * are moved to the end of a zone during a compaction run and the run
 118 * completes when free_pfn <= migrate_pfn
 119 */
 120struct compact_control {
 121        struct list_head freepages;     /* List of free pages to migrate to */
 122        struct list_head migratepages;  /* List of pages being migrated */
 123        unsigned long nr_freepages;     /* Number of isolated free pages */
 124        unsigned long nr_migratepages;  /* Number of pages to migrate */
 125        unsigned long free_pfn;         /* isolate_freepages search base */
 126        unsigned long migrate_pfn;      /* isolate_migratepages search base */
 127        bool sync;                      /* Synchronous migration */
 128        bool ignore_skip_hint;          /* Scan blocks even if marked skip */
 129        bool finished_update_free;      /* True when the zone cached pfns are
 130                                         * no longer being updated
 131                                         */
 132        bool finished_update_migrate;
 133
 134        int order;                      /* order a direct compactor needs */
 135        int migratetype;                /* MOVABLE, RECLAIMABLE etc */
 136        struct zone *zone;
 137        bool contended;                 /* True if a lock was contended */
 138};
 139
 140unsigned long
 141isolate_freepages_range(struct compact_control *cc,
 142                        unsigned long start_pfn, unsigned long end_pfn);
 143unsigned long
 144isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 145        unsigned long low_pfn, unsigned long end_pfn, bool unevictable);
 146
 147#endif
 148
 149/*
 150 * function for dealing with page's order in buddy system.
 151 * zone->lock is already acquired when we use these.
 152 * So, we don't need atomic page->flags operations here.
 153 */
 154static inline unsigned long page_order(struct page *page)
 155{
 156        /* PageBuddy() must be checked by the caller */
 157        return page_private(page);
 158}
 159
 160/* mm/util.c */
 161void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 162                struct vm_area_struct *prev, struct rb_node *rb_parent);
 163
 164#ifdef CONFIG_MMU
 165extern long mlock_vma_pages_range(struct vm_area_struct *vma,
 166                        unsigned long start, unsigned long end);
 167extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 168                        unsigned long start, unsigned long end);
 169static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 170{
 171        munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 172}
 173
 174/*
 175 * Called only in fault path, to determine if a new page is being
 176 * mapped into a LOCKED vma.  If it is, mark page as mlocked.
 177 */
 178static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
 179                                    struct page *page)
 180{
 181        VM_BUG_ON(PageLRU(page));
 182
 183        if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
 184                return 0;
 185
 186        if (!TestSetPageMlocked(page)) {
 187                mod_zone_page_state(page_zone(page), NR_MLOCK,
 188                                    hpage_nr_pages(page));
 189                count_vm_event(UNEVICTABLE_PGMLOCKED);
 190        }
 191        return 1;
 192}
 193
 194/*
 195 * must be called with vma's mmap_sem held for read or write, and page locked.
 196 */
 197extern void mlock_vma_page(struct page *page);
 198extern void munlock_vma_page(struct page *page);
 199
 200/*
 201 * Clear the page's PageMlocked().  This can be useful in a situation where
 202 * we want to unconditionally remove a page from the pagecache -- e.g.,
 203 * on truncation or freeing.
 204 *
 205 * It is legal to call this function for any page, mlocked or not.
 206 * If called for a page that is still mapped by mlocked vmas, all we do
 207 * is revert to lazy LRU behaviour -- semantics are not broken.
 208 */
 209extern void clear_page_mlock(struct page *page);
 210
 211/*
 212 * mlock_migrate_page - called only from migrate_page_copy() to
 213 * migrate the Mlocked page flag; update statistics.
 214 */
 215static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 216{
 217        if (TestClearPageMlocked(page)) {
 218                unsigned long flags;
 219                int nr_pages = hpage_nr_pages(page);
 220
 221                local_irq_save(flags);
 222                __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 223                SetPageMlocked(newpage);
 224                __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
 225                local_irq_restore(flags);
 226        }
 227}
 228
 229extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 230
 231#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 232extern unsigned long vma_address(struct page *page,
 233                                 struct vm_area_struct *vma);
 234#endif
 235#else /* !CONFIG_MMU */
 236static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
 237{
 238        return 0;
 239}
 240static inline void clear_page_mlock(struct page *page) { }
 241static inline void mlock_vma_page(struct page *page) { }
 242static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 243
 244#endif /* !CONFIG_MMU */
 245
 246/*
 247 * Return the mem_map entry representing the 'offset' subpage within
 248 * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 249 * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 250 */
 251static inline struct page *mem_map_offset(struct page *base, int offset)
 252{
 253        if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 254                return pfn_to_page(page_to_pfn(base) + offset);
 255        return base + offset;
 256}
 257
 258/*
 259 * Iterator over all subpages within the maximally aligned gigantic
 260 * page 'base'.  Handle any discontiguity in the mem_map.
 261 */
 262static inline struct page *mem_map_next(struct page *iter,
 263                                                struct page *base, int offset)
 264{
 265        if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 266                unsigned long pfn = page_to_pfn(base) + offset;
 267                if (!pfn_valid(pfn))
 268                        return NULL;
 269                return pfn_to_page(pfn);
 270        }
 271        return iter + 1;
 272}
 273
 274/*
 275 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 276 * so all functions starting at paging_init should be marked __init
 277 * in those cases. SPARSEMEM, however, allows for memory hotplug,
 278 * and alloc_bootmem_node is not used.
 279 */
 280#ifdef CONFIG_SPARSEMEM
 281#define __paginginit __meminit
 282#else
 283#define __paginginit __init
 284#endif
 285
 286/* Memory initialisation debug and verification */
 287enum mminit_level {
 288        MMINIT_WARNING,
 289        MMINIT_VERIFY,
 290        MMINIT_TRACE
 291};
 292
 293#ifdef CONFIG_DEBUG_MEMORY_INIT
 294
 295extern int mminit_loglevel;
 296
 297#define mminit_dprintk(level, prefix, fmt, arg...) \
 298do { \
 299        if (level < mminit_loglevel) { \
 300                printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
 301                printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
 302        } \
 303} while (0)
 304
 305extern void mminit_verify_pageflags_layout(void);
 306extern void mminit_verify_page_links(struct page *page,
 307                enum zone_type zone, unsigned long nid, unsigned long pfn);
 308extern void mminit_verify_zonelist(void);
 309
 310#else
 311
 312static inline void mminit_dprintk(enum mminit_level level,
 313                                const char *prefix, const char *fmt, ...)
 314{
 315}
 316
 317static inline void mminit_verify_pageflags_layout(void)
 318{
 319}
 320
 321static inline void mminit_verify_page_links(struct page *page,
 322                enum zone_type zone, unsigned long nid, unsigned long pfn)
 323{
 324}
 325
 326static inline void mminit_verify_zonelist(void)
 327{
 328}
 329#endif /* CONFIG_DEBUG_MEMORY_INIT */
 330
 331/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 332#if defined(CONFIG_SPARSEMEM)
 333extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 334                                unsigned long *end_pfn);
 335#else
 336static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 337                                unsigned long *end_pfn)
 338{
 339}
 340#endif /* CONFIG_SPARSEMEM */
 341
 342#define ZONE_RECLAIM_NOSCAN     -2
 343#define ZONE_RECLAIM_FULL       -1
 344#define ZONE_RECLAIM_SOME       0
 345#define ZONE_RECLAIM_SUCCESS    1
 346
 347extern int hwpoison_filter(struct page *p);
 348
 349extern u32 hwpoison_filter_dev_major;
 350extern u32 hwpoison_filter_dev_minor;
 351extern u64 hwpoison_filter_flags_mask;
 352extern u64 hwpoison_filter_flags_value;
 353extern u64 hwpoison_filter_memcg;
 354extern u32 hwpoison_filter_enable;
 355
 356extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
 357        unsigned long, unsigned long,
 358        unsigned long, unsigned long);
 359
 360extern void set_pageblock_order(void);
 361unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 362                                            struct list_head *page_list);
 363/* The ALLOC_WMARK bits are used as an index to zone->watermark */
 364#define ALLOC_WMARK_MIN         WMARK_MIN
 365#define ALLOC_WMARK_LOW         WMARK_LOW
 366#define ALLOC_WMARK_HIGH        WMARK_HIGH
 367#define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 368
 369/* Mask to get the watermark bits */
 370#define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 371
 372#define ALLOC_HARDER            0x10 /* try to alloc harder */
 373#define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 374#define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 375#define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 376
 377#endif  /* __MM_INTERNAL_H */
 378
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