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-rw-r--r--include/linux/mm.h25
1 files changed, 20 insertions, 5 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 24c395694f4..9d65ae4ba0e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -620,13 +620,22 @@ void page_address_init(void);
/*
* On an anonymous page mapped into a user virtual memory area,
* page->mapping points to its anon_vma, not to a struct address_space;
- * with the PAGE_MAPPING_ANON bit set to distinguish it.
+ * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
+ *
+ * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
+ * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
+ * and then page->mapping points, not to an anon_vma, but to a private
+ * structure which KSM associates with that merged page. See ksm.h.
+ *
+ * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
*
* Please note that, confusingly, "page_mapping" refers to the inode
* address_space which maps the page from disk; whereas "page_mapped"
* refers to user virtual address space into which the page is mapped.
*/
#define PAGE_MAPPING_ANON 1
+#define PAGE_MAPPING_KSM 2
+#define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
extern struct address_space swapper_space;
static inline struct address_space *page_mapping(struct page *page)
@@ -634,16 +643,19 @@ static inline struct address_space *page_mapping(struct page *page)
struct address_space *mapping = page->mapping;
VM_BUG_ON(PageSlab(page));
-#ifdef CONFIG_SWAP
if (unlikely(PageSwapCache(page)))
mapping = &swapper_space;
- else
-#endif
- if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
+ else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
mapping = NULL;
return mapping;
}
+/* Neutral page->mapping pointer to address_space or anon_vma or other */
+static inline void *page_rmapping(struct page *page)
+{
+ return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS);
+}
+
static inline int PageAnon(struct page *page)
{
return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
@@ -758,6 +770,7 @@ unsigned long unmap_vmas(struct mmu_gather **tlb,
* @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
* @pte_entry: if set, called for each non-empty PTE (4th-level) entry
* @pte_hole: if set, called for each hole at all levels
+ * @hugetlb_entry: if set, called for each hugetlb entry
*
* (see walk_page_range for more details)
*/
@@ -767,6 +780,8 @@ struct mm_walk {
int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, struct mm_walk *);
int (*pte_entry)(pte_t *, unsigned long, unsigned long, struct mm_walk *);
int (*pte_hole)(unsigned long, unsigned long, struct mm_walk *);
+ int (*hugetlb_entry)(pte_t *, unsigned long, unsigned long,
+ struct mm_walk *);
struct mm_struct *mm;
void *private;
};