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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_PAGE_EXT_H
#define __LINUX_PAGE_EXT_H
#include <linux/types.h>
#include <linux/stacktrace.h>
#include <linux/stackdepot.h>
struct pglist_data;
struct page_ext_operations {
size_t offset;
size_t size;
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,
#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
PAGE_EXT_YOUNG,
PAGE_EXT_IDLE,
#endif
};
/*
* 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;
};
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 */
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