1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_PAGE_EXT_H 3 #define __LINUX_PAGE_EXT_H 4 5 #include <linux/types.h> 6 #include <linux/stacktrace.h> 7 #include <linux/stackdepot.h> 8 9 struct pglist_data; 10 struct page_ext_operations { 11 size_t offset; 12 size_t size; 13 bool (*need)(void); 14 void (*init)(void); 15 }; 16 17 #ifdef CONFIG_PAGE_EXTENSION 18 19 enum page_ext_flags { 20 PAGE_EXT_OWNER, 21 #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) 22 PAGE_EXT_YOUNG, 23 PAGE_EXT_IDLE, 24 #endif 25 }; 26 27 /* 28 * Page Extension can be considered as an extended mem_map. 29 * A page_ext page is associated with every page descriptor. The 30 * page_ext helps us add more information about the page. 31 * All page_ext are allocated at boot or memory hotplug event, 32 * then the page_ext for pfn always exists. 33 */ 34 struct page_ext { 35 unsigned long flags; 36 }; 37 38 extern void pgdat_page_ext_init(struct pglist_data *pgdat); 39 40 #ifdef CONFIG_SPARSEMEM 41 static inline void page_ext_init_flatmem(void) 42 { 43 } 44 extern void page_ext_init(void); 45 #else 46 extern void page_ext_init_flatmem(void); 47 static inline void page_ext_init(void) 48 { 49 } 50 #endif 51 52 struct page_ext *lookup_page_ext(const struct page *page); 53 54 #else /* !CONFIG_PAGE_EXTENSION */ 55 struct page_ext; 56 57 static inline void pgdat_page_ext_init(struct pglist_data *pgdat) 58 { 59 } 60 61 static inline struct page_ext *lookup_page_ext(const struct page *page) 62 { 63 return NULL; 64 } 65 66 static inline void page_ext_init(void) 67 { 68 } 69 70 static inline void page_ext_init_flatmem(void) 71 { 72 } 73 #endif /* CONFIG_PAGE_EXTENSION */ 74 #endif /* __LINUX_PAGE_EXT_H */ 75