summaryrefslogtreecommitdiff
path: root/include/linux/page_ext.h
blob: ed27198cdaf46709423c33eeb8a16451747ec993 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_PAGE_EXT_H
#define __LINUX_PAGE_EXT_H

#include <linux/types.h>
#include <linux/stacktrace.h>
#include <linux/stackdepot.h>

struct pglist_data;
struct page_ext_operations {
	size_t offset;
	size_t size;
	bool (*need)(void);
	void (*init)(void);
};

#ifdef CONFIG_PAGE_EXTENSION

enum page_ext_flags {
	PAGE_EXT_OWNER,
	PAGE_EXT_OWNER_ALLOCATED,
#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
	PAGE_EXT_YOUNG,
	PAGE_EXT_IDLE,
#endif
};

/*
 * Page Extension can be considered as an extended mem_map.
 * A page_ext page is associated with every page descriptor. The
 * page_ext helps us add more information about the page.
 * All page_ext are allocated at boot or memory hotplug event,
 * then the page_ext for pfn always exists.
 */
struct page_ext {
	unsigned long flags;
};

extern unsigned long page_ext_size;
extern void pgdat_page_ext_init(struct pglist_data *pgdat);

#ifdef CONFIG_SPARSEMEM
static inline void page_ext_init_flatmem(void)
{
}
extern void page_ext_init(void);
static inline void page_ext_init_flatmem_late(void)
{
}
#else
extern void page_ext_init_flatmem(void);
extern void page_ext_init_flatmem_late(void);
static inline void page_ext_init(void)
{
}
#endif

extern struct page_ext *page_ext_get(struct page *page);
extern void page_ext_put(struct page_ext *page_ext);

static inline struct page_ext *page_ext_next(struct page_ext *curr)
{
	void *next = curr;
	next += page_ext_size;
	return next;
}

#else /* !CONFIG_PAGE_EXTENSION */
struct page_ext;

static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
{
}

static inline void page_ext_init(void)
{
}

static inline void page_ext_init_flatmem_late(void)
{
}

static inline void page_ext_init_flatmem(void)
{
}

static inline struct page_ext *page_ext_get(struct page *page)
{
	return NULL;
}

static inline void page_ext_put(struct page_ext *page_ext)
{
}
#endif /* CONFIG_PAGE_EXTENSION */
#endif /* __LINUX_PAGE_EXT_H */