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