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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_OWNER,
21 PAGE_EXT_OWNER_ALLOCATED,
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 unsigned long page_ext_size;
40extern void pgdat_page_ext_init(struct pglist_data *pgdat);
41
42#ifdef CONFIG_SPARSEMEM
43static inline void page_ext_init_flatmem(void)
44{
45}
46extern void page_ext_init(void);
47static inline void page_ext_init_flatmem_late(void)
48{
49}
50#else
51extern void page_ext_init_flatmem(void);
52extern void page_ext_init_flatmem_late(void);
53static inline void page_ext_init(void)
54{
55}
56#endif
57
58struct page_ext *lookup_page_ext(const struct page *page);
59
60static inline struct page_ext *page_ext_next(struct page_ext *curr)
61{
62 void *next = curr;
63 next += page_ext_size;
64 return next;
65}
66
67#else /* !CONFIG_PAGE_EXTENSION */
68struct page_ext;
69
70static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
71{
72}
73
74static inline struct page_ext *lookup_page_ext(const struct page *page)
75{
76 return NULL;
77}
78
79static inline void page_ext_init(void)
80{
81}
82
83static inline void page_ext_init_flatmem_late(void)
84{
85}
86
87static inline void page_ext_init_flatmem(void)
88{
89}
90#endif /* CONFIG_PAGE_EXTENSION */
91#endif /* __LINUX_PAGE_EXT_H */
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;
10
11#ifdef CONFIG_PAGE_EXTENSION
12/**
13 * struct page_ext_operations - per page_ext client operations
14 * @offset: Offset to the client's data within page_ext. Offset is returned to
15 * the client by page_ext_init.
16 * @size: The size of the client data within page_ext.
17 * @need: Function that returns true if client requires page_ext.
18 * @init: (optional) Called to initialize client once page_exts are allocated.
19 * @need_shared_flags: True when client is using shared page_ext->flags
20 * field.
21 *
22 * Each Page Extension client must define page_ext_operations in
23 * page_ext_ops array.
24 */
25struct page_ext_operations {
26 size_t offset;
27 size_t size;
28 bool (*need)(void);
29 void (*init)(void);
30 bool need_shared_flags;
31};
32
33/*
34 * The page_ext_flags users must set need_shared_flags to true.
35 */
36enum page_ext_flags {
37 PAGE_EXT_OWNER,
38 PAGE_EXT_OWNER_ALLOCATED,
39#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
40 PAGE_EXT_YOUNG,
41 PAGE_EXT_IDLE,
42#endif
43};
44
45/*
46 * Page Extension can be considered as an extended mem_map.
47 * A page_ext page is associated with every page descriptor. The
48 * page_ext helps us add more information about the page.
49 * All page_ext are allocated at boot or memory hotplug event,
50 * then the page_ext for pfn always exists.
51 */
52struct page_ext {
53 unsigned long flags;
54};
55
56extern bool early_page_ext;
57extern unsigned long page_ext_size;
58extern void pgdat_page_ext_init(struct pglist_data *pgdat);
59
60static inline bool early_page_ext_enabled(void)
61{
62 return early_page_ext;
63}
64
65#ifdef CONFIG_SPARSEMEM
66static inline void page_ext_init_flatmem(void)
67{
68}
69extern void page_ext_init(void);
70static inline void page_ext_init_flatmem_late(void)
71{
72}
73#else
74extern void page_ext_init_flatmem(void);
75extern void page_ext_init_flatmem_late(void);
76static inline void page_ext_init(void)
77{
78}
79#endif
80
81extern struct page_ext *page_ext_get(struct page *page);
82extern void page_ext_put(struct page_ext *page_ext);
83
84static inline void *page_ext_data(struct page_ext *page_ext,
85 struct page_ext_operations *ops)
86{
87 return (void *)(page_ext) + ops->offset;
88}
89
90static inline struct page_ext *page_ext_next(struct page_ext *curr)
91{
92 void *next = curr;
93 next += page_ext_size;
94 return next;
95}
96
97#else /* !CONFIG_PAGE_EXTENSION */
98struct page_ext;
99
100static inline bool early_page_ext_enabled(void)
101{
102 return false;
103}
104
105static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
106{
107}
108
109static inline void page_ext_init(void)
110{
111}
112
113static inline void page_ext_init_flatmem_late(void)
114{
115}
116
117static inline void page_ext_init_flatmem(void)
118{
119}
120
121static inline struct page_ext *page_ext_get(struct page *page)
122{
123 return NULL;
124}
125
126static inline void page_ext_put(struct page_ext *page_ext)
127{
128}
129#endif /* CONFIG_PAGE_EXTENSION */
130#endif /* __LINUX_PAGE_EXT_H */