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eefa864b JK |
1 | #ifndef __LINUX_PAGE_EXT_H |
2 | #define __LINUX_PAGE_EXT_H | |
3 | ||
4 | struct pglist_data; | |
5 | struct page_ext_operations { | |
6 | bool (*need)(void); | |
7 | void (*init)(void); | |
8 | }; | |
9 | ||
10 | #ifdef CONFIG_PAGE_EXTENSION | |
11 | ||
e30825f1 JK |
12 | /* |
13 | * page_ext->flags bits: | |
14 | * | |
15 | * PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to | |
16 | * implement generic debug pagealloc feature. The pages are filled with | |
17 | * poison patterns and set this flag after free_pages(). The poisoned | |
18 | * pages are verified whether the patterns are not corrupted and clear | |
19 | * the flag before alloc_pages(). | |
20 | */ | |
21 | ||
22 | enum page_ext_flags { | |
23 | PAGE_EXT_DEBUG_POISON, /* Page is poisoned */ | |
24 | PAGE_EXT_DEBUG_GUARD, | |
25 | }; | |
26 | ||
eefa864b JK |
27 | /* |
28 | * Page Extension can be considered as an extended mem_map. | |
29 | * A page_ext page is associated with every page descriptor. The | |
30 | * page_ext helps us add more information about the page. | |
31 | * All page_ext are allocated at boot or memory hotplug event, | |
32 | * then the page_ext for pfn always exists. | |
33 | */ | |
34 | struct page_ext { | |
35 | unsigned long flags; | |
36 | }; | |
37 | ||
38 | extern void pgdat_page_ext_init(struct pglist_data *pgdat); | |
39 | ||
40 | #ifdef CONFIG_SPARSEMEM | |
41 | static inline void page_ext_init_flatmem(void) | |
42 | { | |
43 | } | |
44 | extern void page_ext_init(void); | |
45 | #else | |
46 | extern void page_ext_init_flatmem(void); | |
47 | static inline void page_ext_init(void) | |
48 | { | |
49 | } | |
50 | #endif | |
51 | ||
52 | struct page_ext *lookup_page_ext(struct page *page); | |
53 | ||
54 | #else /* !CONFIG_PAGE_EXTENSION */ | |
55 | struct page_ext; | |
56 | ||
57 | static inline void pgdat_page_ext_init(struct pglist_data *pgdat) | |
58 | { | |
59 | } | |
60 | ||
61 | static inline struct page_ext *lookup_page_ext(struct page *page) | |
62 | { | |
63 | return NULL; | |
64 | } | |
65 | ||
66 | static inline void page_ext_init(void) | |
67 | { | |
68 | } | |
69 | ||
70 | static inline void page_ext_init_flatmem(void) | |
71 | { | |
72 | } | |
73 | #endif /* CONFIG_PAGE_EXTENSION */ | |
74 | #endif /* __LINUX_PAGE_EXT_H */ |