diff options
Diffstat (limited to 'include/linux/ksm.h')
| -rw-r--r-- | include/linux/ksm.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/ksm.h b/include/linux/ksm.h index eb2a448981ee..a485c14ecd5d 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -10,6 +10,7 @@ #include <linux/bitops.h> #include <linux/mm.h> #include <linux/sched.h> +#include <linux/vmstat.h> #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, @@ -29,6 +30,27 @@ static inline void ksm_exit(struct mm_struct *mm) if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) __ksm_exit(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. + */ +static inline int PageKsm(struct page *page) +{ + return ((unsigned long)page->mapping == PAGE_MAPPING_ANON); +} + +/* + * But we have to avoid the checking which page_add_anon_rmap() performs. + */ +static inline void page_add_ksm_rmap(struct page *page) +{ + if (atomic_inc_and_test(&page->_mapcount)) { + page->mapping = (void *) PAGE_MAPPING_ANON; + __inc_zone_page_state(page, NR_ANON_PAGES); + } +} #else /* !CONFIG_KSM */ static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, @@ -45,6 +67,13 @@ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) static inline void ksm_exit(struct mm_struct *mm) { } + +static inline int PageKsm(struct page *page) +{ + return 0; +} + +/* No stub required for page_add_ksm_rmap(page) */ #endif /* !CONFIG_KSM */ #endif |