1 /*
2 * Macros for manipulating and testing flags related to a
3 * pageblock_nr_pages number of pages.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation version 2 of the License
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2006
19 *
20 * Original author, Mel Gorman
21 * Major cleanups and reduction of bit operations, Andy Whitcroft
22 */
23 #ifndef PAGEBLOCK_FLAGS_H
24 #define PAGEBLOCK_FLAGS_H
25
26 #include <linux/types.h>
27
28 /* Bit indices that affect a whole block of pages */
29 enum pageblock_bits {
30 PB_migrate,
31 PB_migrate_end = PB_migrate + 3 - 1,
32 /* 3 bits required for migrate types */
33 PB_migrate_skip,/* If set the block is skipped by compaction */
34
35 /*
36 * Assume the bits will always align on a word. If this assumption
37 * changes then get/set pageblock needs updating.
38 */
39 NR_PAGEBLOCK_BITS
40 };
41
42 #ifdef CONFIG_HUGETLB_PAGE
43
44 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
45
46 /* Huge page sizes are variable */
47 extern unsigned int pageblock_order;
48
49 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
50
51 /* Huge pages are a constant size */
52 #define pageblock_order HUGETLB_PAGE_ORDER
53
54 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
55
56 #else /* CONFIG_HUGETLB_PAGE */
57
58 /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
59 #define pageblock_order (MAX_ORDER-1)
60
61 #endif /* CONFIG_HUGETLB_PAGE */
62
63 #define pageblock_nr_pages (1UL << pageblock_order)
64
65 /* Forward declaration */
66 struct page;
67
68 unsigned long get_pfnblock_flags_mask(struct page *page,
69 unsigned long pfn,
70 unsigned long end_bitidx,
71 unsigned long mask);
72
73 void set_pfnblock_flags_mask(struct page *page,
74 unsigned long flags,
75 unsigned long pfn,
76 unsigned long end_bitidx,
77 unsigned long mask);
78
79 /* Declarations for getting and setting flags. See mm/page_alloc.c */
80 #define get_pageblock_flags_group(page, start_bitidx, end_bitidx) \
81 get_pfnblock_flags_mask(page, page_to_pfn(page), \
82 end_bitidx, \
83 (1 << (end_bitidx - start_bitidx + 1)) - 1)
84 #define set_pageblock_flags_group(page, flags, start_bitidx, end_bitidx) \
85 set_pfnblock_flags_mask(page, flags, page_to_pfn(page), \
86 end_bitidx, \
87 (1 << (end_bitidx - start_bitidx + 1)) - 1)
88
89 #ifdef CONFIG_COMPACTION
90 #define get_pageblock_skip(page) \
91 get_pageblock_flags_group(page, PB_migrate_skip, \
92 PB_migrate_skip)
93 #define clear_pageblock_skip(page) \
94 set_pageblock_flags_group(page, 0, PB_migrate_skip, \
95 PB_migrate_skip)
96 #define set_pageblock_skip(page) \
97 set_pageblock_flags_group(page, 1, PB_migrate_skip, \
98 PB_migrate_skip)
99 #else
get_pageblock_skip(struct page * page)100 static inline bool get_pageblock_skip(struct page *page)
101 {
102 return false;
103 }
clear_pageblock_skip(struct page * page)104 static inline void clear_pageblock_skip(struct page *page)
105 {
106 }
set_pageblock_skip(struct page * page)107 static inline void set_pageblock_skip(struct page *page)
108 {
109 }
110 #endif /* CONFIG_COMPACTION */
111
112 #endif /* PAGEBLOCK_FLAGS_H */
113