[linux-2.6-block.git] / include / linux / page_ext.h

#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 */
Commit	Line	Data
eefa864b JK	1	#ifndef __LINUX_PAGE_EXT_H
	2	#define __LINUX_PAGE_EXT_H
	3
48c96a36 JK	4	#include <linux/types.h>
	5	#include <linux/stacktrace.h>
	6
eefa864b JK	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
e30825f1 JK	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,
48c96a36	28	PAGE_EXT_OWNER,
e30825f1 JK	29	};
e30825f1 JK	30
eefa864b JK	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	*/
	38	struct page_ext {
	39	unsigned long flags;
48c96a36 JK	40	#ifdef CONFIG_PAGE_OWNER
	41	unsigned int order;
	42	gfp_t gfp_mask;
94f759d6	43	unsigned int nr_entries;
48c96a36 JK	44	unsigned long trace_entries[8];
48c96a36 JK	45	#endif
eefa864b JK	46	};
	47
	48	extern void pgdat_page_ext_init(struct pglist_data *pgdat);
	49
	50	#ifdef CONFIG_SPARSEMEM
	51	static inline void page_ext_init_flatmem(void)
	52	{
	53	}
	54	extern void page_ext_init(void);
	55	#else
	56	extern void page_ext_init_flatmem(void);
	57	static inline void page_ext_init(void)
	58	{
	59	}
	60	#endif
	61
	62	struct page_ext lookup_page_ext(struct page page);
	63
	64	#else /* !CONFIG_PAGE_EXTENSION */
	65	struct page_ext;
	66
	67	static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
	68	{
	69	}
	70
	71	static inline struct page_ext lookup_page_ext(struct page page)
	72	{
	73	return NULL;
	74	}
	75
	76	static inline void page_ext_init(void)
	77	{
	78	}
	79
	80	static inline void page_ext_init_flatmem(void)
	81	{
	82	}
	83	#endif /* CONFIG_PAGE_EXTENSION */
	84	#endif /* __LINUX_PAGE_EXT_H */