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 */
29enum 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 */
47extern 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 */
66struct page;
67
68unsigned long get_pfnblock_flags_mask(struct page *page,
69				unsigned long pfn,
70				unsigned long end_bitidx,
71				unsigned long mask);
72
73void 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 */
102