diff options
Diffstat (limited to 'kernel/include/linux/page_ext.h')
-rw-r--r-- | kernel/include/linux/page_ext.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/kernel/include/linux/page_ext.h b/kernel/include/linux/page_ext.h new file mode 100644 index 000000000..c42981cd9 --- /dev/null +++ b/kernel/include/linux/page_ext.h @@ -0,0 +1,84 @@ +#ifndef __LINUX_PAGE_EXT_H +#define __LINUX_PAGE_EXT_H + +#include <linux/types.h> +#include <linux/stacktrace.h> + +struct pglist_data; +struct page_ext_operations { + bool (*need)(void); + void (*init)(void); +}; + +#ifdef CONFIG_PAGE_EXTENSION + +/* + * page_ext->flags bits: + * + * PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to + * implement generic debug pagealloc feature. The pages are filled with + * poison patterns and set this flag after free_pages(). The poisoned + * pages are verified whether the patterns are not corrupted and clear + * the flag before alloc_pages(). + */ + +enum page_ext_flags { + PAGE_EXT_DEBUG_POISON, /* Page is poisoned */ + PAGE_EXT_DEBUG_GUARD, + PAGE_EXT_OWNER, +}; + +/* + * Page Extension can be considered as an extended mem_map. + * A page_ext page is associated with every page descriptor. The + * page_ext helps us add more information about the page. + * All page_ext are allocated at boot or memory hotplug event, + * then the page_ext for pfn always exists. + */ +struct page_ext { + unsigned long flags; +#ifdef CONFIG_PAGE_OWNER + unsigned int order; + gfp_t gfp_mask; + unsigned int nr_entries; + unsigned long trace_entries[8]; +#endif +}; + +extern void pgdat_page_ext_init(struct pglist_data *pgdat); + +#ifdef CONFIG_SPARSEMEM +static inline void page_ext_init_flatmem(void) +{ +} +extern void page_ext_init(void); +#else +extern void page_ext_init_flatmem(void); +static inline void page_ext_init(void) +{ +} +#endif + +struct page_ext *lookup_page_ext(struct page *page); + +#else /* !CONFIG_PAGE_EXTENSION */ +struct page_ext; + +static inline void pgdat_page_ext_init(struct pglist_data *pgdat) +{ +} + +static inline struct page_ext *lookup_page_ext(struct page *page) +{ + return NULL; +} + +static inline void page_ext_init(void) +{ +} + +static inline void page_ext_init_flatmem(void) +{ +} +#endif /* CONFIG_PAGE_EXTENSION */ +#endif /* __LINUX_PAGE_EXT_H */ |