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Diffstat (limited to 'include/linux/ksm.h')
-rw-r--r--include/linux/ksm.h24
1 files changed, 17 insertions, 7 deletions
diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 1401a313fa77..ef55ce14a2ce 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -12,6 +12,8 @@
#include <linux/sched.h>
#include <linux/vmstat.h>
+struct stable_node;
+
#ifdef CONFIG_KSM
int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
unsigned long end, int advice, unsigned long *vm_flags);
@@ -34,7 +36,8 @@ static inline void ksm_exit(struct mm_struct *mm)
/*
* A KSM page is one of those write-protected "shared pages" or "merged pages"
* which KSM maps into multiple mms, wherever identical anonymous page content
- * is found in VM_MERGEABLE vmas. It's a PageAnon page, with NULL anon_vma.
+ * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
+ * anon_vma, but to that page's node of the stable tree.
*/
static inline int PageKsm(struct page *page)
{
@@ -42,15 +45,22 @@ static inline int PageKsm(struct page *page)
(PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
}
-/*
- * But we have to avoid the checking which page_add_anon_rmap() performs.
- */
+static inline struct stable_node *page_stable_node(struct page *page)
+{
+ return PageKsm(page) ? page_rmapping(page) : NULL;
+}
+
+static inline void set_page_stable_node(struct page *page,
+ struct stable_node *stable_node)
+{
+ page->mapping = (void *)stable_node +
+ (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
+}
+
static inline void page_add_ksm_rmap(struct page *page)
{
- if (atomic_inc_and_test(&page->_mapcount)) {
- page->mapping = (void *) (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
+ if (atomic_inc_and_test(&page->_mapcount))
__inc_zone_page_state(page, NR_ANON_PAGES);
- }
}
#else /* !CONFIG_KSM */