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/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
 104/*
 105 * function for dealing with page's order in buddy system.
 106 * zone->lock is already acquired when we use these.
 107 * So, we don't need atomic page->flags operations here.
 108 */
 109static inline unsigned long page_order(struct page *page)
 110{
 111        /* PageBuddy() must be checked by the caller */
 112        return page_private(page);
 113}
 114
 115/* mm/util.c */
 116void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 117                struct vm_area_struct *prev, struct rb_node *rb_parent);
 118
 119#ifdef CONFIG_MMU
 120extern long mlock_vma_pages_range(struct vm_area_struct *vma,
 121                        unsigned long start, unsigned long end);
 122extern void munlock_vma_pages_range(struct vm_area_struct *vma,
 123                        unsigned long start, unsigned long end);
 124static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
 125{
 126        munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
 127}
 128
 129/*
 130 * Called only in fault path via page_evictable() for a new page
 131 * to determine if it's being mapped into a LOCKED vma.
 132 * If so, mark page as mlocked.
 133 */
 134static inline int is_mlocked_vma(struct vm_area_struct *vma, struct page *page)
 135{
 136        VM_BUG_ON(PageLRU(page));
 137
 138        if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
 139                return 0;
 140
 141        if (!TestSetPageMlocked(page)) {
 142                inc_zone_page_state(page, NR_MLOCK);
 143                count_vm_event(UNEVICTABLE_PGMLOCKED);
 144        }
 145        return 1;
 146}
 147
 148/*
 149 * must be called with vma's mmap_sem held for read or write, and page locked.
 150 */
 151extern void mlock_vma_page(struct page *page);
 152extern void munlock_vma_page(struct page *page);
 153
 154/*
 155 * Clear the page's PageMlocked().  This can be useful in a situation where
 156 * we want to unconditionally remove a page from the pagecache -- e.g.,
 157 * on truncation or freeing.
 158 *
 159 * It is legal to call this function for any page, mlocked or not.
 160 * If called for a page that is still mapped by mlocked vmas, all we do
 161 * is revert to lazy LRU behaviour -- semantics are not broken.
 162 */
 163extern void __clear_page_mlock(struct page *page);
 164static inline void clear_page_mlock(struct page *page)
 165{
 166        if (unlikely(TestClearPageMlocked(page)))
 167                __clear_page_mlock(page);
 168}
 169
 170/*
 171 * mlock_migrate_page - called only from migrate_page_copy() to
 172 * migrate the Mlocked page flag; update statistics.
 173 */
 174static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 175{
 176        if (TestClearPageMlocked(page)) {
 177                unsigned long flags;
 178
 179                local_irq_save(flags);
 180                __dec_zone_page_state(page, NR_MLOCK);
 181                SetPageMlocked(newpage);
 182                __inc_zone_page_state(newpage, NR_MLOCK);
 183                local_irq_restore(flags);
 184        }
 185}
 186
 187#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 188extern unsigned long vma_address(struct page *page,
 189                                 struct vm_area_struct *vma);
 190#endif
 191#else /* !CONFIG_MMU */
 192static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
 193{
 194        return 0;
 195}
 196static inline void clear_page_mlock(struct page *page) { }
 197static inline void mlock_vma_page(struct page *page) { }
 198static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 199
 200#endif /* !CONFIG_MMU */
 201
 202/*
 203 * Return the mem_map entry representing the 'offset' subpage within
 204 * the maximally aligned gigantic page 'base'.  Handle any discontiguity
 205 * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
 206 */
 207static inline struct page *mem_map_offset(struct page *base, int offset)
 208{
 209        if (unlikely(offset >= MAX_ORDER_NR_PAGES))
 210                return pfn_to_page(page_to_pfn(base) + offset);
 211        return base + offset;
 212}
 213
 214/*
 215 * Iterator over all subpages within the maximally aligned gigantic
 216 * page 'base'.  Handle any discontiguity in the mem_map.
 217 */
 218static inline struct page *mem_map_next(struct page *iter,
 219                                                struct page *base, int offset)
 220{
 221        if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
 222                unsigned long pfn = page_to_pfn(base) + offset;
 223                if (!pfn_valid(pfn))
 224                        return NULL;
 225                return pfn_to_page(pfn);
 226        }
 227        return iter + 1;
 228}
 229
 230/*
 231 * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
 232 * so all functions starting at paging_init should be marked __init
 233 * in those cases. SPARSEMEM, however, allows for memory hotplug,
 234 * and alloc_bootmem_node is not used.
 235 */
 236#ifdef CONFIG_SPARSEMEM
 237#define __paginginit __meminit
 238#else
 239#define __paginginit __init
 240#endif
 241
 242/* Memory initialisation debug and verification */
 243enum mminit_level {
 244        MMINIT_WARNING,
 245        MMINIT_VERIFY,
 246        MMINIT_TRACE
 247};
 248
 249#ifdef CONFIG_DEBUG_MEMORY_INIT
 250
 251extern int mminit_loglevel;
 252
 253#define mminit_dprintk(level, prefix, fmt, arg...) \
 254do { \
 255        if (level < mminit_loglevel) { \
 256                printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
 257                printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
 258        } \
 259} while (0)
 260
 261extern void mminit_verify_pageflags_layout(void);
 262extern void mminit_verify_page_links(struct page *page,
 263                enum zone_type zone, unsigned long nid, unsigned long pfn);
 264extern void mminit_verify_zonelist(void);
 265
 266#else
 267
 268static inline void mminit_dprintk(enum mminit_level level,
 269                                const char *prefix, const char *fmt, ...)
 270{
 271}
 272
 273static inline void mminit_verify_pageflags_layout(void)
 274{
 275}
 276
 277static inline void mminit_verify_page_links(struct page *page,
 278                enum zone_type zone, unsigned long nid, unsigned long pfn)
 279{
 280}
 281
 282static inline void mminit_verify_zonelist(void)
 283{
 284}
 285#endif /* CONFIG_DEBUG_MEMORY_INIT */
 286
 287/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
 288#if defined(CONFIG_SPARSEMEM)
 289extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 290                                unsigned long *end_pfn);
 291#else
 292static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
 293                                unsigned long *end_pfn)
 294{
 295}
 296#endif /* CONFIG_SPARSEMEM */
 297
 298#define ZONE_RECLAIM_NOSCAN     -2
 299#define ZONE_RECLAIM_FULL       -1
 300#define ZONE_RECLAIM_SOME       0
 301#define ZONE_RECLAIM_SUCCESS    1
 302#endif
 303
 304extern int hwpoison_filter(struct page *p);
 305
 306extern u32 hwpoison_filter_dev_major;
 307extern u32 hwpoison_filter_dev_minor;
 308extern u64 hwpoison_filter_flags_mask;
 309extern u64 hwpoison_filter_flags_value;
 310extern u64 hwpoison_filter_memcg;
 311extern u32 hwpoison_filter_enable;
 312
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