1#ifndef __LINUX_PAGE_EXT_H 2#define __LINUX_PAGE_EXT_H 3 4#include <linux/types.h> 5#include <linux/stacktrace.h> 6 7struct pglist_data; 8struct 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 25enum page_ext_flags { 26 PAGE_EXT_DEBUG_POISON, /* Page is poisoned */ 27 PAGE_EXT_DEBUG_GUARD, 28 PAGE_EXT_OWNER, 29}; 30 31/* 32 * Page Extension can be considered as an extended mem_map. 33 * A page_ext page is associated with every page descriptor. The 34 * page_ext helps us add more information about the page. 35 * All page_ext are allocated at boot or memory hotplug event, 36 * then the page_ext for pfn always exists. 37 */ 38struct page_ext { 39 unsigned long flags; 40#ifdef CONFIG_PAGE_OWNER 41 unsigned int order; 42 gfp_t gfp_mask; 43 unsigned int nr_entries; 44 unsigned long trace_entries[8]; 45#endif 46}; 47 48extern void pgdat_page_ext_init(struct pglist_data *pgdat); 49 50#ifdef CONFIG_SPARSEMEM 51static inline void page_ext_init_flatmem(void) 52{ 53} 54extern void page_ext_init(void); 55#else 56extern void page_ext_init_flatmem(void); 57static inline void page_ext_init(void) 58{ 59} 60#endif 61 62struct page_ext *lookup_page_ext(struct page *page); 63 64#else /* !CONFIG_PAGE_EXTENSION */ 65struct page_ext; 66 67static inline void pgdat_page_ext_init(struct pglist_data *pgdat) 68{ 69} 70 71static inline struct page_ext *lookup_page_ext(struct page *page) 72{ 73 return NULL; 74} 75 76static inline void page_ext_init(void) 77{ 78} 79 80static inline void page_ext_init_flatmem(void) 81{ 82} 83#endif /* CONFIG_PAGE_EXTENSION */ 84#endif /* __LINUX_PAGE_EXT_H */ 85