1 #ifndef __LINUX_PAGE_EXT_H 2 #define __LINUX_PAGE_EXT_H 3 4 #include <linux/types.h> 5 #include <linux/stacktrace.h> 6 7 struct pglist_data; 8 struct page_ext_operations { 9 bool (*need)(void); 10 void (*init)(void); 11 }; 12 13 #ifdef CONFIG_PAGE_EXTENSION 14 15 /* 16 * page_ext->flags bits: 17 * 18 * PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to 19 * implement generic debug pagealloc feature. The pages are filled with 20 * poison patterns and set this flag after free_pages(). The poisoned 21 * pages are verified whether the patterns are not corrupted and clear 22 * the flag before alloc_pages(). 23 */ 24 25 enum page_ext_flags { 26 PAGE_EXT_DEBUG_POISON, /* Page is poisoned */ 27 PAGE_EXT_DEBUG_GUARD, 28 PAGE_EXT_OWNER, 29 #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) 30 PAGE_EXT_YOUNG, 31 PAGE_EXT_IDLE, 32 #endif 33 }; 34 35 /* 36 * Page Extension can be considered as an extended mem_map. 37 * A page_ext page is associated with every page descriptor. The 38 * page_ext helps us add more information about the page. 39 * All page_ext are allocated at boot or memory hotplug event, 40 * then the page_ext for pfn always exists. 41 */ 42 struct page_ext { 43 unsigned long flags; 44 #ifdef CONFIG_PAGE_OWNER 45 unsigned int order; 46 gfp_t gfp_mask; 47 unsigned int nr_entries; 48 int last_migrate_reason; 49 unsigned long trace_entries[8]; 50 #endif 51 }; 52 53 extern void pgdat_page_ext_init(struct pglist_data *pgdat); 54 55 #ifdef CONFIG_SPARSEMEM 56 static inline void page_ext_init_flatmem(void) 57 { 58 } 59 extern void page_ext_init(void); 60 #else 61 extern void page_ext_init_flatmem(void); 62 static inline void page_ext_init(void) 63 { 64 } 65 #endif 66 67 struct page_ext *lookup_page_ext(struct page *page); 68 69 #else /* !CONFIG_PAGE_EXTENSION */ 70 struct page_ext; 71 72 static inline void pgdat_page_ext_init(struct pglist_data *pgdat) 73 { 74 } 75 76 static inline struct page_ext *lookup_page_ext(struct page *page) 77 { 78 return NULL; 79 } 80 81 static inline void page_ext_init(void) 82 { 83 } 84 85 static inline void page_ext_init_flatmem(void) 86 { 87 } 88 #endif /* CONFIG_PAGE_EXTENSION */ 89 #endif /* __LINUX_PAGE_EXT_H */ 90