#ifndef _LINUX_RMAP_H #define _LINUX_RMAP_H /* * Declarations for Reverse Mapping functions in mm/rmap.c */ #include <linux/list.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/spinlock.h> #include <linux/memcontrol.h> /* * The anon_vma heads a list of private "related" vmas, to scan if * an anonymous page pointing to this anon_vma needs to be unmapped: * the vmas on the list will be related by forking, or by splitting. * * Since vmas come and go as they are split and merged (particularly * in mprotect), the mapping field of an anonymous page cannot point * directly to a vma: instead it points to an anon_vma, on whose list * the related vmas can be easily linked or unlinked. * * After unlinking the last vma on the list, we must garbage collect * the anon_vma object itself: we're guaranteed no page can be * pointing to this anon_vma once its vma list is empty. */ struct anon_vma { struct anon_vma *root; /* Root of this anon_vma tree */ spinlock_t lock; /* Serialize access to vma list */ #if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION) /* * The external_refcount is taken by either KSM or page migration * to take a reference to an anon_vma when there is no * guarantee that the vma of page tables will exist for * the duration of the operation. A caller that takes * the reference is responsible for clearing up the * anon_vma if they are the last user on release */ atomic_t external_refcount; #endif /* * NOTE: the LSB of the head.next is set by * mm_take_all_locks() _after_ taking the above lock. So the * head must only be read/written after taking the above lock * to be sure to see a valid next pointer. The LSB bit itself * is serialized by a system wide lock only visible to * mm_take_all_locks() (mm_all_locks_mutex). */ struct list_head head; /* Chain of private "related" vmas */ }; /* * The copy-on-write semantics of fork mean that an anon_vma * can become associated with multiple processes. Furthermore, * each child process will have its own anon_vma, where new * pages for that process are instantiated. * * This structure allows us to find the anon_vmas associated * with a VMA, or the VMAs associated with an anon_vma. * The "same_vma" list contains the anon_vma_chains linking * all the anon_vmas associated with this VMA. * The "same_anon_vma" list contains the anon_vma_chains * which link all the VMAs associated with this anon_vma. */ struct anon_vma_chain { struct vm_area_struct *vma; struct anon_vma *anon_vma; struct list_head same_vma; /* locked by mmap_sem & page_table_lock */ struct list_head same_anon_vma; /* locked by anon_vma->lock */ }; #ifdef CONFIG_MMU #if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION) static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma) { atomic_set(&anon_vma->external_refcount, 0); } static inline int anonvma_external_refcount(struct anon_vma *anon_vma) { return atomic_read(&anon_vma->external_refcount); } static inline void get_anon_vma(struct anon_vma *anon_vma) { atomic_inc(&anon_vma->external_refcount); } void drop_anon_vma(struct anon_vma *); #else static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma) { } static inline int anonvma_external_refcount(struct anon_vma *anon_vma) { return 0; } static inline void get_anon_vma(struct anon_vma *anon_vma) { } static inline void drop_anon_vma(struct anon_vma *anon_vma) { } #endif /* CONFIG_KSM */ static inline struct anon_vma *page_anon_vma(struct page *page) { if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON) return NULL; return page_rmapping(page); } static inline void vma_lock_anon_vma(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) spin_lock(&anon_vma->root->lock); } static inline void vma_unlock_anon_vma(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) spin_unlock(&anon_vma->root->lock); } static inline void anon_vma_lock(struct anon_vma *anon_vma) { spin_lock(&anon_vma->root->lock); } static inline void anon_vma_unlock(struct anon_vma *anon_vma) { spin_unlock(&anon_vma->root->lock); } /* * anon_vma helper functions. */ void anon_vma_init(void); /* create anon_vma_cachep */ int anon_vma_prepare(struct vm_area_struct *); void unlink_anon_vmas(struct vm_area_struct *); int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); void __anon_vma_link(struct vm_area_struct *); void anon_vma_free(struct anon_vma *); static inline void anon_vma_merge(struct vm_area_struct *vma, struct vm_area_struct *next) { VM_BUG_ON(vma->anon_vma != next->anon_vma); unlink_anon_vmas(next); } /* * rmap interfaces called when adding or removing pte of page */ void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void do_page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long, int); void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void page_add_file_rmap(struct page *); void page_remove_rmap(struct page *); void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); static inline void page_dup_rmap(struct page *page) { atomic_inc(&page->_mapcount); } /* * Called from mm/vmscan.c to handle paging out */ int page_referenced(struct page *, int is_locked, struct mem_cgroup *cnt, unsigned long *vm_flags); int page_referenced_one(struct page *, struct vm_area_struct *, unsigned long address, unsigned int *mapcount, unsigned long *vm_flags); enum ttu_flags { TTU_UNMAP = 0, /* unmap mode */ TTU_MIGRATION = 1, /* migration mode */ TTU_MUNLOCK = 2, /* munlock mode */ TTU_ACTION_MASK = 0xff, TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ }; #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK) bool is_vma_temporary_stack(struct vm_area_struct *vma); int try_to_unmap(struct page *, enum ttu_flags flags); int try_to_unmap_one(struct page *, struct vm_area_struct *, unsigned long address, enum ttu_flags flags); /* * Called from mm/filemap_xip.c to unmap empty zero page */ pte_t *__page_check_address(struct page *, struct mm_struct *, unsigned long, spinlock_t **, int); static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm, unsigned long address, spinlock_t **ptlp, int sync) { pte_t *ptep; __cond_lock(*ptlp, ptep = __page_check_address(page, mm, address, ptlp, sync)); return ptep; } /* * Used by swapoff to help locate where page is expected in vma. */ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); /* * Cleans the PTEs of shared mappings. * (and since clean PTEs should also be readonly, write protects them too) * * returns the number of cleaned PTEs. */ int page_mkclean(struct page *); /* * called in munlock()/munmap() path to check for other vmas holding * the page mlocked. */ int try_to_munlock(struct page *); /* * Called by memory-failure.c to kill processes. */ struct anon_vma *__page_lock_anon_vma(struct page *page); static inline struct anon_vma *page_lock_anon_vma(struct page *page) { struct anon_vma *anon_vma; __cond_lock(RCU, anon_vma = __page_lock_anon_vma(page)); /* (void) is needed to make gcc happy */ (void) __cond_lock(&anon_vma->root->lock, anon_vma); return anon_vma; } void page_unlock_anon_vma(struct anon_vma *anon_vma); int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); /* * Called by migrate.c to remove migration ptes, but might be used more later. */ int rmap_walk(struct page *page, int (*rmap_one)(struct page *, struct vm_area_struct *, unsigned long, void *), void *arg); #else /* !CONFIG_MMU */ #define anon_vma_init() do {} while (0) #define anon_vma_prepare(vma) (0) #define anon_vma_link(vma) do {} while (0) static inline int page_referenced(struct page *page, int is_locked, struct mem_cgroup *cnt, unsigned long *vm_flags) { *vm_flags = 0; return 0; } #define try_to_unmap(page, refs) SWAP_FAIL static inline int page_mkclean(struct page *page) { return 0; } #endif /* CONFIG_MMU */ /* * Return values of try_to_unmap */ #define SWAP_SUCCESS 0 #define SWAP_AGAIN 1 #define SWAP_FAIL 2 #define SWAP_MLOCK 3 #endif /* _LINUX_RMAP_H */