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 #define PB_migratetype_bits 3
  29 /* Bit indices that affect a whole block of pages */
  30 enum pageblock_bits {
  31         PB_migrate,
  32         PB_migrate_end = PB_migrate + PB_migratetype_bits - 1,
  33                         /* 3 bits required for migrate types */
  34         PB_migrate_skip,/* If set the block is skipped by compaction */
  35
  36         /*
  37          * Assume the bits will always align on a word. If this assumption
  38          * changes then get/set pageblock needs updating.
  39          */
  40         NR_PAGEBLOCK_BITS
  41 };
  42
  43 #ifdef CONFIG_HUGETLB_PAGE
  44
  45 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  46
  47 /* Huge page sizes are variable */
  48 extern unsigned int pageblock_order;
  49
  50 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  51
  52 /* Huge pages are a constant size */
  53 #define pageblock_order         HUGETLB_PAGE_ORDER
  54
  55 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  56
  57 #else /* CONFIG_HUGETLB_PAGE */
  58
  59 /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
  60 #define pageblock_order         (MAX_ORDER-1)
  61
  62 #endif /* CONFIG_HUGETLB_PAGE */
  63
  64 #define pageblock_nr_pages      (1UL << pageblock_order)
  65
  66 /* Forward declaration */
  67 struct page;
  68
  69 unsigned long get_pfnblock_flags_mask(struct page *page,
  70                                 unsigned long pfn,
  71                                 unsigned long end_bitidx,
  72                                 unsigned long mask);
  73
  74 void set_pfnblock_flags_mask(struct page *page,
  75                                 unsigned long flags,
  76                                 unsigned long pfn,
  77                                 unsigned long end_bitidx,
  78                                 unsigned long mask);
  79
  80 /* Declarations for getting and setting flags. See mm/page_alloc.c */
  81 #define get_pageblock_flags_group(page, start_bitidx, end_bitidx) \
  82         get_pfnblock_flags_mask(page, page_to_pfn(page),                \
  83                         end_bitidx,                                     \
  84                         (1 << (end_bitidx - start_bitidx + 1)) - 1)
  85 #define set_pageblock_flags_group(page, flags, start_bitidx, end_bitidx) \
  86         set_pfnblock_flags_mask(page, flags, page_to_pfn(page),         \
  87                         end_bitidx,                                     \
  88                         (1 << (end_bitidx - start_bitidx + 1)) - 1)
  89
  90 #ifdef CONFIG_COMPACTION
  91 #define get_pageblock_skip(page) \
  92                         get_pageblock_flags_group(page, PB_migrate_skip,     \
  93                                                         PB_migrate_skip)
  94 #define clear_pageblock_skip(page) \
  95                         set_pageblock_flags_group(page, 0, PB_migrate_skip,  \
  96                                                         PB_migrate_skip)
  97 #define set_pageblock_skip(page) \
  98                         set_pageblock_flags_group(page, 1, PB_migrate_skip,  \
  99                                                         PB_migrate_skip)
 100 #else
 101 static inline bool get_pageblock_skip(struct page *page)
 102 {
 103         return false;
 104 }
 105 static inline void clear_pageblock_skip(struct page *page)
 106 {
 107 }
 108 static inline void set_pageblock_skip(struct page *page)
 109 {
 110 }
 111 #endif /* CONFIG_COMPACTION */
 112
 113 #endif  /* PAGEBLOCK_FLAGS_H */