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_PAGE_PINNER) 23 /* page refcount was increased by GUP or follow_page(FOLL_GET) */ 24 PAGE_EXT_GET, 25 /* page migration failed */ 26 PAGE_EXT_PINNER_MIGRATION_FAILED, 27 #endif 28 #if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT) 29 PAGE_EXT_YOUNG, 30 PAGE_EXT_IDLE, 31 #endif 32 }; 33 34 /* 35 * Page Extension can be considered as an extended mem_map. 36 * A page_ext page is associated with every page descriptor. The 37 * page_ext helps us add more information about the page. 38 * All page_ext are allocated at boot or memory hotplug event, 39 * then the page_ext for pfn always exists. 40 */ 41 struct page_ext { 42 unsigned long flags; 43 }; 44 45 extern unsigned long page_ext_size; 46 extern void pgdat_page_ext_init(struct pglist_data *pgdat); 47 48 #ifdef CONFIG_SPARSEMEM page_ext_init_flatmem(void)49static inline void page_ext_init_flatmem(void) 50 { 51 } 52 extern void page_ext_init(void); 53 #else 54 extern void page_ext_init_flatmem(void); page_ext_init(void)55static inline void page_ext_init(void) 56 { 57 } 58 #endif 59 struct page_ext *lookup_page_ext(const struct page *page); 60 extern struct page_ext *page_ext_get(struct page *page); 61 extern void page_ext_put(struct page_ext *page_ext); 62 page_ext_next(struct page_ext * curr)63static inline struct page_ext *page_ext_next(struct page_ext *curr) 64 { 65 void *next = curr; 66 next += page_ext_size; 67 return next; 68 } 69 70 #else /* !CONFIG_PAGE_EXTENSION */ 71 struct page_ext; 72 pgdat_page_ext_init(struct pglist_data * pgdat)73static inline void pgdat_page_ext_init(struct pglist_data *pgdat) 74 { 75 } 76 page_ext_init(void)77static inline void page_ext_init(void) 78 { 79 } 80 page_ext_init_flatmem(void)81static inline void page_ext_init_flatmem(void) 82 { 83 } 84 page_ext_get(struct page * page)85static inline struct page_ext *page_ext_get(struct page *page) 86 { 87 return NULL; 88 } 89 page_ext_put(struct page_ext * page_ext)90static inline void page_ext_put(struct page_ext *page_ext) 91 { 92 } 93 #endif /* CONFIG_PAGE_EXTENSION */ 94 #endif /* __LINUX_PAGE_EXT_H */ 95