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 PAGE_EXT_OWNER_ALLOCATED, 22 #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) 23 PAGE_EXT_YOUNG, 24 PAGE_EXT_IDLE, 25 #endif 26 }; 27 28 /* 29 * Page Extension can be considered as an extended mem_map. 30 * A page_ext page is associated with every page descriptor. The 31 * page_ext helps us add more information about the page. 32 * All page_ext are allocated at boot or memory hotplug event, 33 * then the page_ext for pfn always exists. 34 */ 35 struct page_ext { 36 unsigned long flags; 37 }; 38 39 extern unsigned long page_ext_size; 40 extern void pgdat_page_ext_init(struct pglist_data *pgdat); 41 42 #ifdef CONFIG_SPARSEMEM page_ext_init_flatmem(void)43static inline void page_ext_init_flatmem(void) 44 { 45 } 46 extern void page_ext_init(void); 47 #else 48 extern void page_ext_init_flatmem(void); page_ext_init(void)49static inline void page_ext_init(void) 50 { 51 } 52 #endif 53 54 struct page_ext *lookup_page_ext(const struct page *page); 55 page_ext_next(struct page_ext * curr)56static inline struct page_ext *page_ext_next(struct page_ext *curr) 57 { 58 void *next = curr; 59 next += page_ext_size; 60 return next; 61 } 62 63 #else /* !CONFIG_PAGE_EXTENSION */ 64 struct page_ext; 65 pgdat_page_ext_init(struct pglist_data * pgdat)66static inline void pgdat_page_ext_init(struct pglist_data *pgdat) 67 { 68 } 69 lookup_page_ext(const struct page * page)70static inline struct page_ext *lookup_page_ext(const struct page *page) 71 { 72 return NULL; 73 } 74 page_ext_init(void)75static inline void page_ext_init(void) 76 { 77 } 78 page_ext_init_flatmem(void)79static inline void page_ext_init_flatmem(void) 80 { 81 } 82 #endif /* CONFIG_PAGE_EXTENSION */ 83 #endif /* __LINUX_PAGE_EXT_H */ 84