/*
* Macros for manipulating and testing flags related to a
* pageblock_nr_pages number of pages.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2006
*
* Original author, Mel Gorman
* Major cleanups and reduction of bit operations, Andy Whitcroft
*/
#ifndef PAGEBLOCK_FLAGS_H
#define PAGEBLOCK_FLAGS_H

#include <linux/types.h>

/* Bit indices that affect a whole block of pages */
enum pageblock_bits {
PB_migrate,
PB_migrate_end = PB_migrate + 3 - 1,
/* 3 bits required for migrate types */
#ifdef CONFIG_COMPACTION
PB_migrate_skip,/* If set the block is skipped by compaction */
#endif /* CONFIG_COMPACTION */
NR_PAGEBLOCK_BITS
};

#ifdef CONFIG_HUGETLB_PAGE

#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE

/* Huge page sizes are variable */
extern int pageblock_order;

#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */

/* Huge pages are a constant size */
#define pageblock_order HUGETLB_PAGE_ORDER

#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */

#else /* CONFIG_HUGETLB_PAGE */

/* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
#define pageblock_order (MAX_ORDER-1)

#endif /* CONFIG_HUGETLB_PAGE */

#define pageblock_nr_pages (1UL << pageblock_order)

/* Forward declaration */
struct page;

/* Declarations for getting and setting flags. See mm/page_alloc.c */
unsigned long get_pageblock_flags_group(struct page *page,
int start_bitidx, int end_bitidx);
void set_pageblock_flags_group(struct page *page, unsigned long flags,
int start_bitidx, int end_bitidx);

#ifdef CONFIG_COMPACTION
#define get_pageblock_skip(page) \
get_pageblock_flags_group(page, PB_migrate_skip, \
PB_migrate_skip)
#define clear_pageblock_skip(page) \
set_pageblock_flags_group(page, 0, PB_migrate_skip, \
PB_migrate_skip)
#define set_pageblock_skip(page) \
set_pageblock_flags_group(page, 1, PB_migrate_skip, \
PB_migrate_skip)
#endif /* CONFIG_COMPACTION */

#endif /* PAGEBLOCK_FLAGS_H */