linux/include/linux/pageblock-flags.h
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   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#ifdef CONFIG_COMPACTION
  34        PB_migrate_skip,/* If set the block is skipped by compaction */
  35#endif /* CONFIG_COMPACTION */
  36        NR_PAGEBLOCK_BITS
  37};
  38
  39#ifdef CONFIG_HUGETLB_PAGE
  40
  41#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  42
  43/* Huge page sizes are variable */
  44extern int pageblock_order;
  45
  46#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  47
  48/* Huge pages are a constant size */
  49#define pageblock_order         HUGETLB_PAGE_ORDER
  50
  51#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  52
  53#else /* CONFIG_HUGETLB_PAGE */
  54
  55/* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
  56#define pageblock_order         (MAX_ORDER-1)
  57
  58#endif /* CONFIG_HUGETLB_PAGE */
  59
  60#define pageblock_nr_pages      (1UL << pageblock_order)
  61
  62/* Forward declaration */
  63struct page;
  64
  65/* Declarations for getting and setting flags. See mm/page_alloc.c */
  66unsigned long get_pageblock_flags_group(struct page *page,
  67                                        int start_bitidx, int end_bitidx);
  68void set_pageblock_flags_group(struct page *page, unsigned long flags,
  69                                        int start_bitidx, int end_bitidx);
  70
  71#ifdef CONFIG_COMPACTION
  72#define get_pageblock_skip(page) \
  73                        get_pageblock_flags_group(page, PB_migrate_skip,     \
  74                                                        PB_migrate_skip)
  75#define clear_pageblock_skip(page) \
  76                        set_pageblock_flags_group(page, 0, PB_migrate_skip,  \
  77                                                        PB_migrate_skip)
  78#define set_pageblock_skip(page) \
  79                        set_pageblock_flags_group(page, 1, PB_migrate_skip,  \
  80                                                        PB_migrate_skip)
  81#endif /* CONFIG_COMPACTION */
  82
  83#define get_pageblock_flags(page) \
  84                        get_pageblock_flags_group(page, 0, PB_migrate_end)
  85#define set_pageblock_flags(page, flags) \
  86                        set_pageblock_flags_group(page, flags,  \
  87                                                  0, PB_migrate_end)
  88
  89#endif  /* PAGEBLOCK_FLAGS_H */
  90
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