1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_PAGE_EXT_H
3 #define __LINUX_PAGE_EXT_H
5 #include <linux/types.h>
6 #include <linux/stacktrace.h>
7 #include <linux/stackdepot.h>
12 * struct page_ext_operations - per page_ext client operations
13 * @offset: Offset to the client's data within page_ext. Offset is returned to
14 * the client by page_ext_init.
15 * @size: The size of the client data within page_ext.
16 * @need: Function that returns true if client requires page_ext.
17 * @init: (optional) Called to initialize client once page_exts are allocated.
18 * @need_shared_flags: True when client is using shared page_ext->flags
21 * Each Page Extension client must define page_ext_operations in
24 struct page_ext_operations {
29 bool need_shared_flags;
32 extern bool deferred_struct_pages;
34 #ifdef CONFIG_PAGE_EXTENSION
37 * The page_ext_flags users must set need_shared_flags to true.
41 PAGE_EXT_OWNER_ALLOCATED,
42 #if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
49 * Page Extension can be considered as an extended mem_map.
50 * A page_ext page is associated with every page descriptor. The
51 * page_ext helps us add more information about the page.
52 * All page_ext are allocated at boot or memory hotplug event,
53 * then the page_ext for pfn always exists.
59 extern bool early_page_ext;
60 extern unsigned long page_ext_size;
61 extern void pgdat_page_ext_init(struct pglist_data *pgdat);
63 static inline bool early_page_ext_enabled(void)
65 return early_page_ext;
68 #ifdef CONFIG_SPARSEMEM
69 static inline void page_ext_init_flatmem(void)
72 extern void page_ext_init(void);
73 static inline void page_ext_init_flatmem_late(void)
77 extern void page_ext_init_flatmem(void);
78 extern void page_ext_init_flatmem_late(void);
79 static inline void page_ext_init(void)
84 extern struct page_ext *page_ext_get(struct page *page);
85 extern void page_ext_put(struct page_ext *page_ext);
87 static inline struct page_ext *page_ext_next(struct page_ext *curr)
90 next += page_ext_size;
94 #else /* !CONFIG_PAGE_EXTENSION */
97 static inline bool early_page_ext_enabled(void)
102 static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
106 static inline void page_ext_init(void)
110 static inline void page_ext_init_flatmem_late(void)
114 static inline void page_ext_init_flatmem(void)
118 static inline struct page_ext *page_ext_get(struct page *page)
123 static inline void page_ext_put(struct page_ext *page_ext)
126 #endif /* CONFIG_PAGE_EXTENSION */
127 #endif /* __LINUX_PAGE_EXT_H */