include/linux/page_ext.h

   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 */