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 start_free_pfn;   /* where we started the search */
 122        unsigned long migrate_pfn;      /* isolate_migratepages search base */
 123        bool sync;                      /* Synchronous migration */
 124        bool wrapped;                   /* Order > 0 compactions are
 125                                           incremental, once free_pfn
 126                                           and migrate_pfn meet, we restart
 127                                           from the top of the zone;
 128                                           remember we wrapped around. */
 129
 130        int order;                      /* order a direct compactor needs */
 131        int migratetype;                /* MOVABLE, RECLAIMABLE etc */
 132        struct zone *zone;
 133        bool *contended;                /* True if a lock was contended */
 134};
 135
 136unsigned long
 137isolate_freepages_range(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);
 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);
 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 via page_evictable() for a new page
 171 * to determine if it's being mapped into a LOCKED vma.
 172 * If so, mark page as mlocked.
 173 */
 174static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
 175                                    struct page *page)
 176{
 177        VM_BUG_ON(PageLRU(page));
 178
 179        if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
 180                return 0;
 181
 182        if (!TestSetPageMlocked(page)) {
 183                inc_zone_page_state(page, NR_MLOCK);
 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 void 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);
 205static inline void clear_page_mlock(struct page *page)
 206{
 207        if (unlikely(TestClearPageMlocked(page)))
 208                __clear_page_mlock(page);
 209}
 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
 220                local_irq_save(flags);
 221                __dec_zone_page_state(page, NR_MLOCK);
 222                SetPageMlocked(newpage);
 223                __inc_zone_page_state(newpage, NR_MLOCK);
 224                local_irq_restore(flags);
 225        }
 226}
 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#endif
 344
 345extern int hwpoison_filter(struct page *p);
 346
 347extern u32 hwpoison_filter_dev_major;
 348extern u32 hwpoison_filter_dev_minor;
 349extern u64 hwpoison_filter_flags_mask;
 350extern u64 hwpoison_filter_flags_value;
 351extern u64 hwpoison_filter_memcg;
 352extern u32 hwpoison_filter_enable;
 353
 354extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
 355        unsigned long, unsigned long,
 356        unsigned long, unsigned long);
 357
 358extern void set_pageblock_order(void);
 359
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