| #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 { |
| spinlock_t lock; /* Serialize access to vma list */ |
| /* |
| * 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; /* List of private "related" vmas */ |
| }; |
| |
| #ifdef CONFIG_MMU |
| |
| static inline void anon_vma_lock(struct vm_area_struct *vma) |
| { |
| struct anon_vma *anon_vma = vma->anon_vma; |
| if (anon_vma) |
| spin_lock(&anon_vma->lock); |
| } |
| |
| static inline void anon_vma_unlock(struct vm_area_struct *vma) |
| { |
| struct anon_vma *anon_vma = vma->anon_vma; |
| if (anon_vma) |
| spin_unlock(&anon_vma->lock); |
| } |
| |
| /* |
| * anon_vma helper functions. |
| */ |
| void anon_vma_init(void); /* create anon_vma_cachep */ |
| int anon_vma_prepare(struct vm_area_struct *); |
| void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *); |
| void anon_vma_unlink(struct vm_area_struct *); |
| void anon_vma_link(struct vm_area_struct *); |
| void __anon_vma_link(struct vm_area_struct *); |
| |
| /* |
| * rmap interfaces called when adding or removing pte of page |
| */ |
| void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
| 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 *, struct vm_area_struct *); |
| |
| #ifdef CONFIG_DEBUG_VM |
| void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address); |
| #else |
| static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) |
| { |
| atomic_inc(&page->_mapcount); |
| } |
| #endif |
| |
| /* |
| * Called from mm/vmscan.c to handle paging out |
| */ |
| int page_referenced(struct page *, int is_locked, struct mem_cgroup *cnt); |
| int try_to_unmap(struct page *, int ignore_refs); |
| |
| /* |
| * 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); |
| |
| /* |
| * 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 *); |
| |
| #ifdef CONFIG_UNEVICTABLE_LRU |
| /* |
| * called in munlock()/munmap() path to check for other vmas holding |
| * the page mlocked. |
| */ |
| int try_to_munlock(struct page *); |
| #else |
| static inline int try_to_munlock(struct page *page) |
| { |
| return 0; /* a.k.a. SWAP_SUCCESS */ |
| } |
| #endif |
| |
| #else /* !CONFIG_MMU */ |
| |
| #define anon_vma_init() do {} while (0) |
| #define anon_vma_prepare(vma) (0) |
| #define anon_vma_link(vma) do {} while (0) |
| |
| #define page_referenced(page,l,cnt) TestClearPageReferenced(page) |
| #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 */ |