FreeBSD/Linux Kernel Cross Reference
sys/mm/internal.h

     /* internal.h: mm/ internal definitions
      *
      * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
      * Written by David Howells (dhowells@redhat.com)
      *
      * This program is free software; you can redistribute it and/or
      * modify it under the terms of the GNU General Public License
      * as published by the Free Software Foundation; either version
      * 2 of the License, or (at your option) any later version.
     */
    #ifndef __MM_INTERNAL_H
    #define __MM_INTERNAL_H
    
    #include <linux/mm.h>
    
    void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
                    unsigned long floor, unsigned long ceiling);
    
    static inline void set_page_count(struct page *page, int v)
    {
            atomic_set(&page->_count, v);
    }
    
    /*
     * Turn a non-refcounted page (->_count == 0) into refcounted with
     * a count of one.
     */
    static inline void set_page_refcounted(struct page *page)
    {
            VM_BUG_ON(PageTail(page));
            VM_BUG_ON(atomic_read(&page->_count));
            set_page_count(page, 1);
    }
    
    static inline void __put_page(struct page *page)
    {
            atomic_dec(&page->_count);
    }
    
    static inline void __get_page_tail_foll(struct page *page,
                                            bool get_page_head)
    {
            /*
             * If we're getting a tail page, the elevated page->_count is
             * required only in the head page and we will elevate the head
             * page->_count and tail page->_mapcount.
             *
             * We elevate page_tail->_mapcount for tail pages to force
             * page_tail->_count to be zero at all times to avoid getting
             * false positives from get_page_unless_zero() with
             * speculative page access (like in
             * page_cache_get_speculative()) on tail pages.
             */
            VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0);
            VM_BUG_ON(atomic_read(&page->_count) != 0);
            VM_BUG_ON(page_mapcount(page) < 0);
            if (get_page_head)
                    atomic_inc(&page->first_page->_count);
            atomic_inc(&page->_mapcount);
    }
    
    /*
     * This is meant to be called as the FOLL_GET operation of
     * follow_page() and it must be called while holding the proper PT
     * lock while the pte (or pmd_trans_huge) is still mapping the page.
     */
    static inline void get_page_foll(struct page *page)
    {
            if (unlikely(PageTail(page)))
                    /*
                     * This is safe only because
                     * __split_huge_page_refcount() can't run under
                     * get_page_foll() because we hold the proper PT lock.
                     */
                    __get_page_tail_foll(page, true);
            else {
                    /*
                     * Getting a normal page or the head of a compound page
                     * requires to already have an elevated page->_count.
                     */
                    VM_BUG_ON(atomic_read(&page->_count) <= 0);
                    atomic_inc(&page->_count);
            }
    }
    
    extern unsigned long highest_memmap_pfn;
    
    /*
     * in mm/vmscan.c:
     */
    extern int isolate_lru_page(struct page *page);
    extern void putback_lru_page(struct page *page);
    
    /*
     * in mm/rmap.c:
     */
    extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
    
    /*
    * in mm/page_alloc.c
    */
   extern void __free_pages_bootmem(struct page *page, unsigned int order);
   extern void prep_compound_page(struct page *page, unsigned long order);
   #ifdef CONFIG_MEMORY_FAILURE
   extern bool is_free_buddy_page(struct page *page);
   #endif
   
   #if defined CONFIG_COMPACTION || defined CONFIG_CMA
   
   /*
    * in mm/compaction.c
    */
   /*
    * compact_control is used to track pages being migrated and the free pages
    * they are being migrated to during memory compaction. The free_pfn starts
    * at the end of a zone and migrate_pfn begins at the start. Movable pages
    * are moved to the end of a zone during a compaction run and the run
    * completes when free_pfn <= migrate_pfn
    */
   struct compact_control {
           struct list_head freepages;     /* List of free pages to migrate to */
           struct list_head migratepages;  /* List of pages being migrated */
           unsigned long nr_freepages;     /* Number of isolated free pages */
           unsigned long nr_migratepages;  /* Number of pages to migrate */
           unsigned long free_pfn;         /* isolate_freepages search base */
           unsigned long migrate_pfn;      /* isolate_migratepages search base */
           bool sync;                      /* Synchronous migration */
           bool ignore_skip_hint;          /* Scan blocks even if marked skip */
           bool finished_update_free;      /* True when the zone cached pfns are
                                            * no longer being updated
                                            */
           bool finished_update_migrate;
   
           int order;                      /* order a direct compactor needs */
           int migratetype;                /* MOVABLE, RECLAIMABLE etc */
           struct zone *zone;
           bool contended;                 /* True if a lock was contended */
   };
   
   unsigned long
   isolate_freepages_range(struct compact_control *cc,
                           unsigned long start_pfn, unsigned long end_pfn);
   unsigned long
   isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
           unsigned long low_pfn, unsigned long end_pfn, bool unevictable);
   
   #endif
   
   /*
    * function for dealing with page's order in buddy system.
    * zone->lock is already acquired when we use these.
    * So, we don't need atomic page->flags operations here.
    */
   static inline unsigned long page_order(struct page *page)
   {
           /* PageBuddy() must be checked by the caller */
           return page_private(page);
   }
   
   /* mm/util.c */
   void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
                   struct vm_area_struct *prev, struct rb_node *rb_parent);
   
   #ifdef CONFIG_MMU
   extern long mlock_vma_pages_range(struct vm_area_struct *vma,
                           unsigned long start, unsigned long end);
   extern void munlock_vma_pages_range(struct vm_area_struct *vma,
                           unsigned long start, unsigned long end);
   static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
   {
           munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
   }
   
   /*
    * Called only in fault path, to determine if a new page is being
    * mapped into a LOCKED vma.  If it is, mark page as mlocked.
    */
   static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
                                       struct page *page)
   {
           VM_BUG_ON(PageLRU(page));
   
           if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
                   return 0;
   
           if (!TestSetPageMlocked(page)) {
                   mod_zone_page_state(page_zone(page), NR_MLOCK,
                                       hpage_nr_pages(page));
                   count_vm_event(UNEVICTABLE_PGMLOCKED);
           }
           return 1;
   }
   
   /*
    * must be called with vma's mmap_sem held for read or write, and page locked.
    */
   extern void mlock_vma_page(struct page *page);
   extern void munlock_vma_page(struct page *page);
   
   /*
    * Clear the page's PageMlocked().  This can be useful in a situation where
    * we want to unconditionally remove a page from the pagecache -- e.g.,
    * on truncation or freeing.
    *
    * It is legal to call this function for any page, mlocked or not.
    * If called for a page that is still mapped by mlocked vmas, all we do
    * is revert to lazy LRU behaviour -- semantics are not broken.
    */
   extern void clear_page_mlock(struct page *page);
   
   /*
    * mlock_migrate_page - called only from migrate_page_copy() to
    * migrate the Mlocked page flag; update statistics.
    */
   static inline void mlock_migrate_page(struct page *newpage, struct page *page)
   {
           if (TestClearPageMlocked(page)) {
                   unsigned long flags;
                   int nr_pages = hpage_nr_pages(page);
   
                   local_irq_save(flags);
                   __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
                   SetPageMlocked(newpage);
                   __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
                   local_irq_restore(flags);
           }
   }
   
   extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
   
   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
   extern unsigned long vma_address(struct page *page,
                                    struct vm_area_struct *vma);
   #endif
   #else /* !CONFIG_MMU */
   static inline int mlocked_vma_newpage(struct vm_area_struct *v, struct page *p)
   {
           return 0;
   }
   static inline void clear_page_mlock(struct page *page) { }
   static inline void mlock_vma_page(struct page *page) { }
   static inline void mlock_migrate_page(struct page *new, struct page *old) { }
   
   #endif /* !CONFIG_MMU */
   
   /*
    * Return the mem_map entry representing the 'offset' subpage within
    * the maximally aligned gigantic page 'base'.  Handle any discontiguity
    * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
    */
   static inline struct page *mem_map_offset(struct page *base, int offset)
   {
           if (unlikely(offset >= MAX_ORDER_NR_PAGES))
                   return pfn_to_page(page_to_pfn(base) + offset);
           return base + offset;
   }
   
   /*
    * Iterator over all subpages within the maximally aligned gigantic
    * page 'base'.  Handle any discontiguity in the mem_map.
    */
   static inline struct page *mem_map_next(struct page *iter,
                                                   struct page *base, int offset)
   {
           if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
                   unsigned long pfn = page_to_pfn(base) + offset;
                   if (!pfn_valid(pfn))
                           return NULL;
                   return pfn_to_page(pfn);
           }
           return iter + 1;
   }
   
   /*
    * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
    * so all functions starting at paging_init should be marked __init
    * in those cases. SPARSEMEM, however, allows for memory hotplug,
    * and alloc_bootmem_node is not used.
    */
   #ifdef CONFIG_SPARSEMEM
   #define __paginginit __meminit
   #else
   #define __paginginit __init
   #endif
   
   /* Memory initialisation debug and verification */
   enum mminit_level {
           MMINIT_WARNING,
           MMINIT_VERIFY,
           MMINIT_TRACE
   };
   
   #ifdef CONFIG_DEBUG_MEMORY_INIT
   
   extern int mminit_loglevel;
   
   #define mminit_dprintk(level, prefix, fmt, arg...) \
   do { \
           if (level < mminit_loglevel) { \
                   printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
                   printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
           } \
   } while (0)
   
   extern void mminit_verify_pageflags_layout(void);
   extern void mminit_verify_page_links(struct page *page,
                   enum zone_type zone, unsigned long nid, unsigned long pfn);
   extern void mminit_verify_zonelist(void);
   
   #else
   
   static inline void mminit_dprintk(enum mminit_level level,
                                   const char *prefix, const char *fmt, ...)
   {
   }
   
   static inline void mminit_verify_pageflags_layout(void)
   {
   }
   
   static inline void mminit_verify_page_links(struct page *page,
                   enum zone_type zone, unsigned long nid, unsigned long pfn)
   {
   }
   
   static inline void mminit_verify_zonelist(void)
   {
   }
   #endif /* CONFIG_DEBUG_MEMORY_INIT */
   
   /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
   #if defined(CONFIG_SPARSEMEM)
   extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
                                   unsigned long *end_pfn);
   #else
   static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
                                   unsigned long *end_pfn)
   {
   }
   #endif /* CONFIG_SPARSEMEM */
   
   #define ZONE_RECLAIM_NOSCAN     -2
   #define ZONE_RECLAIM_FULL       -1
   #define ZONE_RECLAIM_SOME       0
   #define ZONE_RECLAIM_SUCCESS    1
   
   extern int hwpoison_filter(struct page *p);
   
   extern u32 hwpoison_filter_dev_major;
   extern u32 hwpoison_filter_dev_minor;
   extern u64 hwpoison_filter_flags_mask;
   extern u64 hwpoison_filter_flags_value;
   extern u64 hwpoison_filter_memcg;
   extern u32 hwpoison_filter_enable;
   
   extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
           unsigned long, unsigned long,
           unsigned long, unsigned long);
   
   extern void set_pageblock_order(void);
   unsigned long reclaim_clean_pages_from_list(struct zone *zone,
                                               struct list_head *page_list);
   /* The ALLOC_WMARK bits are used as an index to zone->watermark */
   #define ALLOC_WMARK_MIN         WMARK_MIN
   #define ALLOC_WMARK_LOW         WMARK_LOW
   #define ALLOC_WMARK_HIGH        WMARK_HIGH
   #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
   
   /* Mask to get the watermark bits */
   #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
   
   #define ALLOC_HARDER            0x10 /* try to alloc harder */
   #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
   #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
   #define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
   
   #endif  /* __MM_INTERNAL_H */

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