1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_PAGE_EXT_H
3#define __LINUX_PAGE_EXT_H
4
5#include <linux/types.h>
6#include <linux/stacktrace.h>
7#include <linux/stackdepot.h>
8
9struct pglist_data;
10struct page_ext_operations {
11 size_t offset;
12 size_t size;
13 bool (*need)(void);
14 void (*init)(void);
15};
16
17#ifdef CONFIG_PAGE_EXTENSION
18
19enum page_ext_flags {
20 PAGE_EXT_DEBUG_GUARD,
21 PAGE_EXT_OWNER,
22#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
23 PAGE_EXT_YOUNG,
24 PAGE_EXT_IDLE,
25#endif
26};
27
28/*
29 * Page Extension can be considered as an extended mem_map.
30 * A page_ext page is associated with every page descriptor. The
31 * page_ext helps us add more information about the page.
32 * All page_ext are allocated at boot or memory hotplug event,
33 * then the page_ext for pfn always exists.
34 */
35struct page_ext {
36 unsigned long flags;
37};
38
39extern void pgdat_page_ext_init(struct pglist_data *pgdat);
40
41#ifdef CONFIG_SPARSEMEM
42static inline void page_ext_init_flatmem(void)
43{
44}
45extern void page_ext_init(void);
46#else
47extern void page_ext_init_flatmem(void);
48static inline void page_ext_init(void)
49{
50}
51#endif
52
53struct page_ext *lookup_page_ext(const struct page *page);
54
55#else /* !CONFIG_PAGE_EXTENSION */
56struct page_ext;
57
58static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
59{
60}
61
62static inline struct page_ext *lookup_page_ext(const struct page *page)
63{
64 return NULL;
65}
66
67static inline void page_ext_init(void)
68{
69}
70
71static inline void page_ext_init_flatmem(void)
72{
73}
74#endif /* CONFIG_PAGE_EXTENSION */
75#endif /* __LINUX_PAGE_EXT_H */
76