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#define PB_migratetype_bits 3
29/* Bit indices that affect a whole block of pages */
30enum pageblock_bits {
31 PB_migrate,
32 PB_migrate_end = PB_migrate + PB_migratetype_bits - 1,
33 /* 3 bits required for migrate types */
34 PB_migrate_skip,/* If set the block is skipped by compaction */
35
36 /*
37 * Assume the bits will always align on a word. If this assumption
38 * changes then get/set pageblock needs updating.
39 */
40 NR_PAGEBLOCK_BITS
41};
42
43#ifdef CONFIG_HUGETLB_PAGE
44
45#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
46
47/* Huge page sizes are variable */
48extern unsigned int pageblock_order;
49
50#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
51
52/* Huge pages are a constant size */
53#define pageblock_order HUGETLB_PAGE_ORDER
54
55#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
56
57#else /* CONFIG_HUGETLB_PAGE */
58
59/* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
60#define pageblock_order (MAX_ORDER-1)
61
62#endif /* CONFIG_HUGETLB_PAGE */
63
64#define pageblock_nr_pages (1UL << pageblock_order)
65
66/* Forward declaration */
67struct page;
68
69unsigned long get_pfnblock_flags_mask(struct page *page,
70 unsigned long pfn,
71 unsigned long end_bitidx,
72 unsigned long mask);
73
74void set_pfnblock_flags_mask(struct page *page,
75 unsigned long flags,
76 unsigned long pfn,
77 unsigned long end_bitidx,
78 unsigned long mask);
79
80/* Declarations for getting and setting flags. See mm/page_alloc.c */
81#define get_pageblock_flags_group(page, start_bitidx, end_bitidx) \
82 get_pfnblock_flags_mask(page, page_to_pfn(page), \
83 end_bitidx, \
84 (1 << (end_bitidx - start_bitidx + 1)) - 1)
85#define set_pageblock_flags_group(page, flags, start_bitidx, end_bitidx) \
86 set_pfnblock_flags_mask(page, flags, page_to_pfn(page), \
87 end_bitidx, \
88 (1 << (end_bitidx - start_bitidx + 1)) - 1)
89
90#ifdef CONFIG_COMPACTION
91#define get_pageblock_skip(page) \
92 get_pageblock_flags_group(page, PB_migrate_skip, \
93 PB_migrate_skip)
94#define clear_pageblock_skip(page) \
95 set_pageblock_flags_group(page, 0, PB_migrate_skip, \
96 PB_migrate_skip)
97#define set_pageblock_skip(page) \
98 set_pageblock_flags_group(page, 1, PB_migrate_skip, \
99 PB_migrate_skip)
100#else
101static inline bool get_pageblock_skip(struct page *page)
102{
103 return false;
104}
105static inline void clear_pageblock_skip(struct page *page)
106{
107}
108static inline void set_pageblock_skip(struct page *page)
109{
110}
111#endif /* CONFIG_COMPACTION */
112
113#endif /* PAGEBLOCK_FLAGS_H */
114