include/linux/pageblock-flags.h

   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 */
  29 enum 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 */
  44 extern 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 */
  63 struct page;
  64
  65 /* Declarations for getting and setting flags. See mm/page_alloc.c */
  66 unsigned long get_pageblock_flags_group(struct page *page,
  67                                         int start_bitidx, int end_bitidx);
  68 void 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 #endif  /* PAGEBLOCK_FLAGS_H */