2 * swapcache pages are stored in the swapper_space radix tree. We want to
3 * get good packing density in that tree, so the index should be dense in
6 * We arrange the `type' and `offset' fields so that `type' is at the five
7 * high-order bits of the swp_entry_t and `offset' is right-aligned in the
10 * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
12 #define SWP_TYPE_SHIFT(e) (sizeof(e.val) * 8 - MAX_SWAPFILES_SHIFT)
13 #define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1)
16 * Store a type+offset into a swp_entry_t in an arch-independent format
18 static inline swp_entry_t
swp_entry(unsigned long type
, pgoff_t offset
)
22 ret
.val
= (type
<< SWP_TYPE_SHIFT(ret
)) |
23 (offset
& SWP_OFFSET_MASK(ret
));
28 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
29 * arch-independent format
31 static inline unsigned swp_type(swp_entry_t entry
)
33 return (entry
.val
>> SWP_TYPE_SHIFT(entry
));
37 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
38 * arch-independent format
40 static inline pgoff_t
swp_offset(swp_entry_t entry
)
42 return entry
.val
& SWP_OFFSET_MASK(entry
);
46 /* check whether a pte points to a swap entry */
47 static inline int is_swap_pte(pte_t pte
)
49 return !pte_none(pte
) && !pte_present(pte
) && !pte_file(pte
);
54 * Convert the arch-dependent pte representation of a swp_entry_t into an
55 * arch-independent swp_entry_t.
57 static inline swp_entry_t
pte_to_swp_entry(pte_t pte
)
59 swp_entry_t arch_entry
;
61 BUG_ON(pte_file(pte
));
62 arch_entry
= __pte_to_swp_entry(pte
);
63 return swp_entry(__swp_type(arch_entry
), __swp_offset(arch_entry
));
67 * Convert the arch-independent representation of a swp_entry_t into the
68 * arch-dependent pte representation.
70 static inline pte_t
swp_entry_to_pte(swp_entry_t entry
)
72 swp_entry_t arch_entry
;
74 arch_entry
= __swp_entry(swp_type(entry
), swp_offset(entry
));
75 BUG_ON(pte_file(__swp_entry_to_pte(arch_entry
)));
76 return __swp_entry_to_pte(arch_entry
);
79 #ifdef CONFIG_MIGRATION
80 static inline swp_entry_t
make_migration_entry(struct page
*page
, int write
)
82 BUG_ON(!PageLocked(page
));
83 return swp_entry(write
? SWP_MIGRATION_WRITE
: SWP_MIGRATION_READ
,
87 static inline int is_migration_entry(swp_entry_t entry
)
89 return unlikely(swp_type(entry
) == SWP_MIGRATION_READ
||
90 swp_type(entry
) == SWP_MIGRATION_WRITE
);
93 static inline int is_write_migration_entry(swp_entry_t entry
)
95 return unlikely(swp_type(entry
) == SWP_MIGRATION_WRITE
);
98 static inline struct page
*migration_entry_to_page(swp_entry_t entry
)
100 struct page
*p
= pfn_to_page(swp_offset(entry
));
102 * Any use of migration entries may only occur while the
103 * corresponding page is locked
105 BUG_ON(!PageLocked(p
));
109 static inline void make_migration_entry_read(swp_entry_t
*entry
)
111 *entry
= swp_entry(SWP_MIGRATION_READ
, swp_offset(*entry
));
114 extern void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
115 unsigned long address
);
118 #define make_migration_entry(page, write) swp_entry(0, 0)
119 static inline int is_migration_entry(swp_entry_t swp
)
123 #define migration_entry_to_page(swp) NULL
124 static inline void make_migration_entry_read(swp_entry_t
*entryp
) { }
125 static inline void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
126 unsigned long address
) { }
127 static inline int is_write_migration_entry(swp_entry_t entry
)
134 #ifdef CONFIG_MEMORY_FAILURE
136 * Support for hardware poisoned pages
138 static inline swp_entry_t
make_hwpoison_entry(struct page
*page
)
140 BUG_ON(!PageLocked(page
));
141 return swp_entry(SWP_HWPOISON
, page_to_pfn(page
));
144 static inline int is_hwpoison_entry(swp_entry_t entry
)
146 return swp_type(entry
) == SWP_HWPOISON
;
150 static inline swp_entry_t
make_hwpoison_entry(struct page
*page
)
152 return swp_entry(0, 0);
155 static inline int is_hwpoison_entry(swp_entry_t swp
)
161 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION)
162 static inline int non_swap_entry(swp_entry_t entry
)
164 return swp_type(entry
) >= MAX_SWAPFILES
;
167 static inline int non_swap_entry(swp_entry_t entry
)
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