Linux kernel mirror (for testing)
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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_PAGE_IDLE_FLAG) && !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 bool early_page_ext;
40extern unsigned long page_ext_size;
41extern void pgdat_page_ext_init(struct pglist_data *pgdat);
42
43static inline bool early_page_ext_enabled(void)
44{
45 return early_page_ext;
46}
47
48#ifdef CONFIG_SPARSEMEM
49static inline void page_ext_init_flatmem(void)
50{
51}
52extern void page_ext_init(void);
53static inline void page_ext_init_flatmem_late(void)
54{
55}
56#else
57extern void page_ext_init_flatmem(void);
58extern void page_ext_init_flatmem_late(void);
59static inline void page_ext_init(void)
60{
61}
62#endif
63
64extern struct page_ext *page_ext_get(struct page *page);
65extern void page_ext_put(struct page_ext *page_ext);
66
67static inline struct page_ext *page_ext_next(struct page_ext *curr)
68{
69 void *next = curr;
70 next += page_ext_size;
71 return next;
72}
73
74#else /* !CONFIG_PAGE_EXTENSION */
75struct page_ext;
76
77static inline bool early_page_ext_enabled(void)
78{
79 return false;
80}
81
82static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
83{
84}
85
86static inline void page_ext_init(void)
87{
88}
89
90static inline void page_ext_init_flatmem_late(void)
91{
92}
93
94static inline void page_ext_init_flatmem(void)
95{
96}
97
98static inline struct page_ext *page_ext_get(struct page *page)
99{
100 return NULL;
101}
102
103static inline void page_ext_put(struct page_ext *page_ext)
104{
105}
106#endif /* CONFIG_PAGE_EXTENSION */
107#endif /* __LINUX_PAGE_EXT_H */