pageblock-flags.h
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/*
* 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 */
PB_migrate_skip,/* If set the block is skipped by compaction */
/*
* Assume the bits will always align on a word. If this assumption
* changes then get/set pageblock needs updating.
*/
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;
unsigned long get_pageblock_flags_mask(struct page *page,
unsigned long end_bitidx,
unsigned long mask);
void set_pageblock_flags_mask(struct page *page,
unsigned long flags,
unsigned long end_bitidx,
unsigned long mask);
/* Declarations for getting and setting flags. See mm/page_alloc.c */
static inline unsigned long get_pageblock_flags_group(struct page *page,
int start_bitidx, int end_bitidx)
{
unsigned long nr_flag_bits = end_bitidx - start_bitidx + 1;
unsigned long mask = (1 << nr_flag_bits) - 1;
return get_pageblock_flags_mask(page, end_bitidx, mask);
}
static inline void set_pageblock_flags_group(struct page *page,
unsigned long flags,
int start_bitidx, int end_bitidx)
{
unsigned long nr_flag_bits = end_bitidx - start_bitidx + 1;
unsigned long mask = (1 << nr_flag_bits) - 1;
set_pageblock_flags_mask(page, flags, end_bitidx, mask);
}
#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 */