diff options
Diffstat (limited to 'include/linux/ksm.h')
| -rw-r--r-- | include/linux/ksm.h | 54 |
1 files changed, 48 insertions, 6 deletions
diff --git a/include/linux/ksm.h b/include/linux/ksm.h index ef55ce14a2c..157d83dbaef 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -9,10 +9,12 @@ #include <linux/bitops.h> #include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/rmap.h> #include <linux/sched.h> -#include <linux/vmstat.h> struct stable_node; +struct mem_cgroup; #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, @@ -57,11 +59,36 @@ static inline void set_page_stable_node(struct page *page, (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); } -static inline void page_add_ksm_rmap(struct page *page) +/* + * When do_swap_page() first faults in from swap what used to be a KSM page, + * no problem, it will be assigned to this vma's anon_vma; but thereafter, + * it might be faulted into a different anon_vma (or perhaps to a different + * offset in the same anon_vma). do_swap_page() cannot do all the locking + * needed to reconstitute a cross-anon_vma KSM page: for now it has to make + * a copy, and leave remerging the pages to a later pass of ksmd. + * + * We'd like to make this conditional on vma->vm_flags & VM_MERGEABLE, + * but what if the vma was unmerged while the page was swapped out? + */ +struct page *ksm_does_need_to_copy(struct page *page, + struct vm_area_struct *vma, unsigned long address); +static inline struct page *ksm_might_need_to_copy(struct page *page, + struct vm_area_struct *vma, unsigned long address) { - if (atomic_inc_and_test(&page->_mapcount)) - __inc_zone_page_state(page, NR_ANON_PAGES); + struct anon_vma *anon_vma = page_anon_vma(page); + + if (!anon_vma || + (anon_vma == vma->anon_vma && + page->index == linear_page_index(vma, address))) + return page; + + return ksm_does_need_to_copy(page, vma, address); } + +int page_referenced_ksm(struct page *page, + struct mem_cgroup *memcg, unsigned long *vm_flags); +int try_to_unmap_ksm(struct page *page, enum ttu_flags flags); + #else /* !CONFIG_KSM */ static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, @@ -84,7 +111,22 @@ static inline int PageKsm(struct page *page) return 0; } -/* No stub required for page_add_ksm_rmap(page) */ +static inline struct page *ksm_might_need_to_copy(struct page *page, + struct vm_area_struct *vma, unsigned long address) +{ + return page; +} + +static inline int page_referenced_ksm(struct page *page, + struct mem_cgroup *memcg, unsigned long *vm_flags) +{ + return 0; +} + +static inline int try_to_unmap_ksm(struct page *page, enum ttu_flags flags) +{ + return 0; +} #endif /* !CONFIG_KSM */ -#endif +#endif /* __LINUX_KSM_H */ |