diff options
| -rw-r--r-- | include/linux/ksm.h | 5 | ||||
| -rw-r--r-- | include/linux/mm.h | 17 | ||||
| -rw-r--r-- | include/linux/rmap.h | 8 | ||||
| -rw-r--r-- | mm/migrate.c | 11 | ||||
| -rw-r--r-- | mm/rmap.c | 7 | ||||
| -rw-r--r-- | mm/swapfile.c | 2 |
6 files changed, 35 insertions, 15 deletions
diff --git a/include/linux/ksm.h b/include/linux/ksm.h index a485c14ecd5..1401a313fa7 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -38,7 +38,8 @@ static inline void ksm_exit(struct mm_struct *mm) */ static inline int PageKsm(struct page *page) { - return ((unsigned long)page->mapping == PAGE_MAPPING_ANON); + return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == + (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); } /* @@ -47,7 +48,7 @@ static inline int PageKsm(struct page *page) 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 = (void *) (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); __inc_zone_page_state(page, NR_ANON_PAGES); } } diff --git a/include/linux/mm.h b/include/linux/mm.h index 24c395694f4..1202cd3121e 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) @@ -644,6 +653,12 @@ static inline struct address_space *page_mapping(struct page *page) 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; diff --git a/include/linux/rmap.h b/include/linux/rmap.h index cb0ba703260..1f65af44c6d 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -39,6 +39,14 @@ struct anon_vma { #ifdef CONFIG_MMU +static inline struct anon_vma *page_anon_vma(struct page *page) +{ + if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != + PAGE_MAPPING_ANON) + return NULL; + return page_rmapping(page); +} + static inline void anon_vma_lock(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; diff --git a/mm/migrate.c b/mm/migrate.c index 576c25eeb1c..367272d0442 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -172,17 +172,14 @@ static void remove_anon_migration_ptes(struct page *old, struct page *new) { struct anon_vma *anon_vma; struct vm_area_struct *vma; - unsigned long mapping; - - mapping = (unsigned long)new->mapping; - - if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0) - return; /* * We hold the mmap_sem lock. So no need to call page_lock_anon_vma. */ - anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON); + anon_vma = page_anon_vma(new); + if (!anon_vma) + return; + spin_lock(&anon_vma->lock); list_for_each_entry(vma, &anon_vma->head, anon_vma_node) diff --git a/mm/rmap.c b/mm/rmap.c index 1a0ee6e634c..f06cee48eca 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -203,7 +203,7 @@ struct anon_vma *page_lock_anon_vma(struct page *page) rcu_read_lock(); anon_mapping = (unsigned long) page->mapping; - if (!(anon_mapping & PAGE_MAPPING_ANON)) + if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON) goto out; if (!page_mapped(page)) goto out; @@ -248,8 +248,7 @@ vma_address(struct page *page, struct vm_area_struct *vma) unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { if (PageAnon(page)) { - if ((void *)vma->anon_vma != - (void *)page->mapping - PAGE_MAPPING_ANON) + if (vma->anon_vma != page_anon_vma(page)) return -EFAULT; } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { if (!vma->vm_file || @@ -513,7 +512,7 @@ int page_referenced(struct page *page, referenced++; *vm_flags = 0; - if (page_mapped(page) && page->mapping) { + if (page_mapped(page) && page_rmapping(page)) { if (PageAnon(page)) referenced += page_referenced_anon(page, mem_cont, vm_flags); diff --git a/mm/swapfile.c b/mm/swapfile.c index d5eb2e85600..e74112e8e5f 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -938,7 +938,7 @@ static int unuse_vma(struct vm_area_struct *vma, unsigned long addr, end, next; int ret; - if (page->mapping) { + if (page_anon_vma(page)) { addr = page_address_in_vma(page, vma); if (addr == -EFAULT) return 0; |