Linux kernel mirror (for testing)
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1#ifndef __LINUX_PAGE_EXT_H
2#define __LINUX_PAGE_EXT_H
3
4#include <linux/types.h>
5#include <linux/stacktrace.h>
6#include <linux/stackdepot.h>
7
8struct pglist_data;
9struct page_ext_operations {
10 size_t offset;
11 size_t size;
12 bool (*need)(void);
13 void (*init)(void);
14};
15
16#ifdef CONFIG_PAGE_EXTENSION
17
18/*
19 * page_ext->flags bits:
20 *
21 * PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to
22 * implement generic debug pagealloc feature. The pages are filled with
23 * poison patterns and set this flag after free_pages(). The poisoned
24 * pages are verified whether the patterns are not corrupted and clear
25 * the flag before alloc_pages().
26 */
27
28enum page_ext_flags {
29 PAGE_EXT_DEBUG_POISON, /* Page is poisoned */
30 PAGE_EXT_DEBUG_GUARD,
31 PAGE_EXT_OWNER,
32#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
33 PAGE_EXT_YOUNG,
34 PAGE_EXT_IDLE,
35#endif
36};
37
38/*
39 * Page Extension can be considered as an extended mem_map.
40 * A page_ext page is associated with every page descriptor. The
41 * page_ext helps us add more information about the page.
42 * All page_ext are allocated at boot or memory hotplug event,
43 * then the page_ext for pfn always exists.
44 */
45struct page_ext {
46 unsigned long flags;
47};
48
49extern void pgdat_page_ext_init(struct pglist_data *pgdat);
50
51#ifdef CONFIG_SPARSEMEM
52static inline void page_ext_init_flatmem(void)
53{
54}
55extern void page_ext_init(void);
56#else
57extern void page_ext_init_flatmem(void);
58static inline void page_ext_init(void)
59{
60}
61#endif
62
63struct page_ext *lookup_page_ext(struct page *page);
64
65#else /* !CONFIG_PAGE_EXTENSION */
66struct page_ext;
67
68static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
69{
70}
71
72static inline struct page_ext *lookup_page_ext(struct page *page)
73{
74 return NULL;
75}
76
77static inline void page_ext_init(void)
78{
79}
80
81static inline void page_ext_init_flatmem(void)
82{
83}
84#endif /* CONFIG_PAGE_EXTENSION */
85#endif /* __LINUX_PAGE_EXT_H */