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         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 */
  47 extern 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 */
  66 struct page;
  67
  68 unsigned long get_pfnblock_flags_mask(struct page *page,
  69                                 unsigned long pfn,
  70                                 unsigned long end_bitidx,
  71                                 unsigned long mask);
  72
  73 void 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 #else
 100 static inline bool get_pageblock_skip(struct page *page)
 101 {
 102         return false;
 103 }
 104 static inline void clear_pageblock_skip(struct page *page)
 105 {
 106 }
 107 static inline void set_pageblock_skip(struct page *page)
 108 {
 109 }
 110 #endif /* CONFIG_COMPACTION */
 111
 112 #endif  /* PAGEBLOCK_FLAGS_H */