Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[linux-2.6-microblaze.git] / include / linux / pageblock-flags.h
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 #endif /* CONFIG_COMPACTION */
100
101 #endif  /* PAGEBLOCK_FLAGS_H */