| #ifndef __LINUX_PAGE_EXT_H |
| #define __LINUX_PAGE_EXT_H |
| |
| struct pglist_data; |
| struct page_ext_operations { |
| bool (*need)(void); |
| void (*init)(void); |
| }; |
| |
| #ifdef CONFIG_PAGE_EXTENSION |
| |
| /* |
| * page_ext->flags bits: |
| * |
| * PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to |
| * implement generic debug pagealloc feature. The pages are filled with |
| * poison patterns and set this flag after free_pages(). The poisoned |
| * pages are verified whether the patterns are not corrupted and clear |
| * the flag before alloc_pages(). |
| */ |
| |
| enum page_ext_flags { |
| PAGE_EXT_DEBUG_POISON, /* Page is poisoned */ |
| PAGE_EXT_DEBUG_GUARD, |
| }; |
| |
| /* |
| * Page Extension can be considered as an extended mem_map. |
| * A page_ext page is associated with every page descriptor. The |
| * page_ext helps us add more information about the page. |
| * All page_ext are allocated at boot or memory hotplug event, |
| * then the page_ext for pfn always exists. |
| */ |
| struct page_ext { |
| unsigned long flags; |
| }; |
| |
| extern void pgdat_page_ext_init(struct pglist_data *pgdat); |
| |
| #ifdef CONFIG_SPARSEMEM |
| static inline void page_ext_init_flatmem(void) |
| { |
| } |
| extern void page_ext_init(void); |
| #else |
| extern void page_ext_init_flatmem(void); |
| static inline void page_ext_init(void) |
| { |
| } |
| #endif |
| |
| struct page_ext *lookup_page_ext(struct page *page); |
| |
| #else /* !CONFIG_PAGE_EXTENSION */ |
| struct page_ext; |
| |
| static inline void pgdat_page_ext_init(struct pglist_data *pgdat) |
| { |
| } |
| |
| static inline struct page_ext *lookup_page_ext(struct page *page) |
| { |
| return NULL; |
| } |
| |
| static inline void page_ext_init(void) |
| { |
| } |
| |
| static inline void page_ext_init_flatmem(void) |
| { |
| } |
| #endif /* CONFIG_PAGE_EXTENSION */ |
| #endif /* __LINUX_PAGE_EXT_H */ |