diff options
Diffstat (limited to 'include/linux/migrate.h')
| -rw-r--r-- | include/linux/migrate.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index ce7e6671968b..0b5865c61efd 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -7,9 +7,27 @@ typedef struct page *new_page_t(struct page *, unsigned long private, int **); +/* + * Return values from addresss_space_operations.migratepage(): + * - negative errno on page migration failure; + * - zero on page migration success; + * + * The balloon page migration introduces this special case where a 'distinct' + * return code is used to flag a successful page migration to unmap_and_move(). + * This approach is necessary because page migration can race against balloon + * deflation procedure, and for such case we could introduce a nasty page leak + * if a successfully migrated balloon page gets released concurrently with + * migration's unmap_and_move() wrap-up steps. + */ +#define MIGRATEPAGE_SUCCESS 0 +#define MIGRATEPAGE_BALLOON_SUCCESS 1 /* special ret code for balloon page + * sucessful migration case. + */ + #ifdef CONFIG_MIGRATION extern void putback_lru_pages(struct list_head *l); +extern void putback_movable_pages(struct list_head *l); extern int migrate_page(struct address_space *, struct page *, struct page *, enum migrate_mode); extern int migrate_pages(struct list_head *l, new_page_t x, @@ -33,6 +51,7 @@ extern int migrate_huge_page_move_mapping(struct address_space *mapping, #else static inline void putback_lru_pages(struct list_head *l) {} +static inline void putback_movable_pages(struct list_head *l) {} static inline int migrate_pages(struct list_head *l, new_page_t x, unsigned long private, bool offlining, enum migrate_mode mode) { return -ENOSYS; } |